Greg Kroah-Hartman | b244131 | 2017-11-01 15:07:57 +0100 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2 | /* |
| 3 | * INET An implementation of the TCP/IP protocol suite for the LINUX |
| 4 | * operating system. INET is implemented using the BSD Socket |
| 5 | * interface as the means of communication with the user level. |
| 6 | * |
| 7 | * Implementation of the Transmission Control Protocol(TCP). |
| 8 | * |
Jesper Juhl | 02c30a8 | 2005-05-05 16:16:16 -0700 | [diff] [blame] | 9 | * Authors: Ross Biro |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 10 | * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> |
| 11 | * Mark Evans, <evansmp@uhura.aston.ac.uk> |
| 12 | * Corey Minyard <wf-rch!minyard@relay.EU.net> |
| 13 | * Florian La Roche, <flla@stud.uni-sb.de> |
| 14 | * Charles Hedrick, <hedrick@klinzhai.rutgers.edu> |
| 15 | * Linus Torvalds, <torvalds@cs.helsinki.fi> |
| 16 | * Alan Cox, <gw4pts@gw4pts.ampr.org> |
| 17 | * Matthew Dillon, <dillon@apollo.west.oic.com> |
| 18 | * Arnt Gulbrandsen, <agulbra@nvg.unit.no> |
| 19 | * Jorge Cwik, <jorge@laser.satlink.net> |
| 20 | */ |
| 21 | |
| 22 | /* |
| 23 | * Changes: |
| 24 | * Pedro Roque : Fast Retransmit/Recovery. |
| 25 | * Two receive queues. |
| 26 | * Retransmit queue handled by TCP. |
| 27 | * Better retransmit timer handling. |
| 28 | * New congestion avoidance. |
| 29 | * Header prediction. |
| 30 | * Variable renaming. |
| 31 | * |
| 32 | * Eric : Fast Retransmit. |
| 33 | * Randy Scott : MSS option defines. |
| 34 | * Eric Schenk : Fixes to slow start algorithm. |
| 35 | * Eric Schenk : Yet another double ACK bug. |
| 36 | * Eric Schenk : Delayed ACK bug fixes. |
| 37 | * Eric Schenk : Floyd style fast retrans war avoidance. |
| 38 | * David S. Miller : Don't allow zero congestion window. |
| 39 | * Eric Schenk : Fix retransmitter so that it sends |
| 40 | * next packet on ack of previous packet. |
| 41 | * Andi Kleen : Moved open_request checking here |
| 42 | * and process RSTs for open_requests. |
| 43 | * Andi Kleen : Better prune_queue, and other fixes. |
Stephen Hemminger | caa20d9a | 2005-11-10 17:13:47 -0800 | [diff] [blame] | 44 | * Andrey Savochkin: Fix RTT measurements in the presence of |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 45 | * timestamps. |
| 46 | * Andrey Savochkin: Check sequence numbers correctly when |
| 47 | * removing SACKs due to in sequence incoming |
| 48 | * data segments. |
| 49 | * Andi Kleen: Make sure we never ack data there is not |
| 50 | * enough room for. Also make this condition |
| 51 | * a fatal error if it might still happen. |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 52 | * Andi Kleen: Add tcp_measure_rcv_mss to make |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 53 | * connections with MSS<min(MTU,ann. MSS) |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 54 | * work without delayed acks. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 55 | * Andi Kleen: Process packets with PSH set in the |
| 56 | * fast path. |
| 57 | * J Hadi Salim: ECN support |
| 58 | * Andrei Gurtov, |
| 59 | * Pasi Sarolahti, |
| 60 | * Panu Kuhlberg: Experimental audit of TCP (re)transmission |
| 61 | * engine. Lots of bugs are found. |
| 62 | * Pasi Sarolahti: F-RTO for dealing with spurious RTOs |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 63 | */ |
| 64 | |
Joe Perches | afd46503 | 2012-03-12 07:03:32 +0000 | [diff] [blame] | 65 | #define pr_fmt(fmt) "TCP: " fmt |
| 66 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 67 | #include <linux/mm.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 68 | #include <linux/slab.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 69 | #include <linux/module.h> |
| 70 | #include <linux/sysctl.h> |
Ilpo Järvinen | a0bffff | 2009-03-21 13:36:17 -0700 | [diff] [blame] | 71 | #include <linux/kernel.h> |
Eric Dumazet | ad971f6 | 2014-10-11 15:17:29 -0700 | [diff] [blame] | 72 | #include <linux/prefetch.h> |
Satoru SATOH | 5ffc02a | 2008-05-04 22:14:42 -0700 | [diff] [blame] | 73 | #include <net/dst.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 74 | #include <net/tcp.h> |
| 75 | #include <net/inet_common.h> |
| 76 | #include <linux/ipsec.h> |
| 77 | #include <asm/unaligned.h> |
Willem de Bruijn | e1c8a60 | 2014-08-04 22:11:50 -0400 | [diff] [blame] | 78 | #include <linux/errqueue.h> |
Song Liu | 5941521 | 2017-10-23 09:20:25 -0700 | [diff] [blame] | 79 | #include <trace/events/tcp.h> |
Ursula Braun | 60e2a77 | 2017-10-25 11:01:45 +0200 | [diff] [blame] | 80 | #include <linux/static_key.h> |
Amritha Nambiar | c6345ce | 2018-06-29 21:26:57 -0700 | [diff] [blame] | 81 | #include <net/busy_poll.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 82 | |
Brian Haley | ab32ea5 | 2006-09-22 14:15:41 -0700 | [diff] [blame] | 83 | int sysctl_tcp_max_orphans __read_mostly = NR_FILE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 84 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 85 | #define FLAG_DATA 0x01 /* Incoming frame contained data. */ |
| 86 | #define FLAG_WIN_UPDATE 0x02 /* Incoming ACK was a window update. */ |
| 87 | #define FLAG_DATA_ACKED 0x04 /* This ACK acknowledged new data. */ |
| 88 | #define FLAG_RETRANS_DATA_ACKED 0x08 /* "" "" some of which was retransmitted. */ |
| 89 | #define FLAG_SYN_ACKED 0x10 /* This ACK acknowledged SYN. */ |
| 90 | #define FLAG_DATA_SACKED 0x20 /* New SACK. */ |
| 91 | #define FLAG_ECE 0x40 /* ECE in this ACK */ |
Yuchung Cheng | 291a00d | 2015-07-01 14:11:14 -0700 | [diff] [blame] | 92 | #define FLAG_LOST_RETRANS 0x80 /* This ACK marks some retransmission lost */ |
Florian Westphal | 31770e3 | 2017-08-30 19:24:58 +0200 | [diff] [blame] | 93 | #define FLAG_SLOWPATH 0x100 /* Do not skip RFC checks for window update.*/ |
Yuchung Cheng | e33099f | 2013-03-20 13:33:00 +0000 | [diff] [blame] | 94 | #define FLAG_ORIG_SACK_ACKED 0x200 /* Never retransmitted data are (s)acked */ |
Ilpo Järvinen | 2e60529 | 2007-08-02 19:46:58 -0700 | [diff] [blame] | 95 | #define FLAG_SND_UNA_ADVANCED 0x400 /* Snd_una was changed (!= FLAG_DATA_ACKED) */ |
Ryousei Takano | 564262c | 2007-10-25 23:03:52 -0700 | [diff] [blame] | 96 | #define FLAG_DSACKING_ACK 0x800 /* SACK blocks contained D-SACK info */ |
Neal Cardwell | df92c83 | 2017-08-03 09:19:54 -0400 | [diff] [blame] | 97 | #define FLAG_SET_XMIT_TIMER 0x1000 /* Set TLP or RTO timer */ |
Ilpo Järvinen | cadbd03 | 2007-12-31 04:49:21 -0800 | [diff] [blame] | 98 | #define FLAG_SACK_RENEGING 0x2000 /* snd_una advanced to a sacked seq */ |
Eric Dumazet | 12fb3dd | 2013-04-19 07:19:48 +0000 | [diff] [blame] | 99 | #define FLAG_UPDATE_TS_RECENT 0x4000 /* tcp_replace_ts_recent() */ |
Eric Dumazet | d0e1a1b | 2017-05-23 15:24:46 -0700 | [diff] [blame] | 100 | #define FLAG_NO_CHALLENGE_ACK 0x8000 /* do not call tcp_send_challenge_ack() */ |
Yuchung Cheng | eb36be0 | 2018-01-17 12:11:00 -0800 | [diff] [blame] | 101 | #define FLAG_ACK_MAYBE_DELAYED 0x10000 /* Likely a delayed ACK */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 102 | |
| 103 | #define FLAG_ACKED (FLAG_DATA_ACKED|FLAG_SYN_ACKED) |
| 104 | #define FLAG_NOT_DUP (FLAG_DATA|FLAG_WIN_UPDATE|FLAG_ACKED) |
Priyaranjan Jha | d09b9e6 | 2017-11-03 17:46:55 -0700 | [diff] [blame] | 105 | #define FLAG_CA_ALERT (FLAG_DATA_SACKED|FLAG_ECE|FLAG_DSACKING_ACK) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 106 | #define FLAG_FORWARD_PROGRESS (FLAG_ACKED|FLAG_DATA_SACKED) |
| 107 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 108 | #define TCP_REMNANT (TCP_FLAG_FIN|TCP_FLAG_URG|TCP_FLAG_SYN|TCP_FLAG_PSH) |
Ilpo Järvinen | bdf1ee5 | 2007-05-27 02:04:16 -0700 | [diff] [blame] | 109 | #define TCP_HP_BITS (~(TCP_RESERVED_BITS|TCP_FLAG_PSH)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 110 | |
Yuchung Cheng | e662ca4 | 2016-02-02 10:33:04 -0800 | [diff] [blame] | 111 | #define REXMIT_NONE 0 /* no loss recovery to do */ |
| 112 | #define REXMIT_LOST 1 /* retransmit packets marked lost */ |
| 113 | #define REXMIT_NEW 2 /* FRTO-style transmit of unsent/new packets */ |
| 114 | |
Ilya Lesokhin | 6dac152 | 2018-04-30 10:16:10 +0300 | [diff] [blame] | 115 | #if IS_ENABLED(CONFIG_TLS_DEVICE) |
| 116 | static DEFINE_STATIC_KEY_FALSE(clean_acked_data_enabled); |
| 117 | |
| 118 | void clean_acked_data_enable(struct inet_connection_sock *icsk, |
| 119 | void (*cad)(struct sock *sk, u32 ack_seq)) |
| 120 | { |
| 121 | icsk->icsk_clean_acked = cad; |
| 122 | static_branch_inc(&clean_acked_data_enabled); |
| 123 | } |
| 124 | EXPORT_SYMBOL_GPL(clean_acked_data_enable); |
| 125 | |
| 126 | void clean_acked_data_disable(struct inet_connection_sock *icsk) |
| 127 | { |
| 128 | static_branch_dec(&clean_acked_data_enabled); |
| 129 | icsk->icsk_clean_acked = NULL; |
| 130 | } |
| 131 | EXPORT_SYMBOL_GPL(clean_acked_data_disable); |
| 132 | #endif |
| 133 | |
Marcelo Ricardo Leitner | 0b9aefe | 2017-04-01 11:00:21 -0300 | [diff] [blame] | 134 | static void tcp_gro_dev_warn(struct sock *sk, const struct sk_buff *skb, |
| 135 | unsigned int len) |
Marcelo Ricardo Leitner | dcb17d2 | 2016-12-05 18:37:13 -0200 | [diff] [blame] | 136 | { |
| 137 | static bool __once __read_mostly; |
| 138 | |
| 139 | if (!__once) { |
| 140 | struct net_device *dev; |
| 141 | |
| 142 | __once = true; |
| 143 | |
| 144 | rcu_read_lock(); |
| 145 | dev = dev_get_by_index_rcu(sock_net(sk), skb->skb_iif); |
Marcelo Ricardo Leitner | 0b9aefe | 2017-04-01 11:00:21 -0300 | [diff] [blame] | 146 | if (!dev || len >= dev->mtu) |
| 147 | pr_warn("%s: Driver has suspect GRO implementation, TCP performance may be compromised.\n", |
| 148 | dev ? dev->name : "Unknown driver"); |
Marcelo Ricardo Leitner | dcb17d2 | 2016-12-05 18:37:13 -0200 | [diff] [blame] | 149 | rcu_read_unlock(); |
| 150 | } |
| 151 | } |
| 152 | |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 153 | /* Adapt the MSS value used to make delayed ack decision to the |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 154 | * real world. |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 155 | */ |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 156 | static void tcp_measure_rcv_mss(struct sock *sk, const struct sk_buff *skb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 157 | { |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 158 | struct inet_connection_sock *icsk = inet_csk(sk); |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 159 | const unsigned int lss = icsk->icsk_ack.last_seg_size; |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 160 | unsigned int len; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 161 | |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 162 | icsk->icsk_ack.last_seg_size = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 163 | |
| 164 | /* skb->len may jitter because of SACKs, even if peer |
| 165 | * sends good full-sized frames. |
| 166 | */ |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 167 | len = skb_shinfo(skb)->gso_size ? : skb->len; |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 168 | if (len >= icsk->icsk_ack.rcv_mss) { |
Marcelo Ricardo Leitner | dcb17d2 | 2016-12-05 18:37:13 -0200 | [diff] [blame] | 169 | icsk->icsk_ack.rcv_mss = min_t(unsigned int, len, |
| 170 | tcp_sk(sk)->advmss); |
Marcelo Ricardo Leitner | 0b9aefe | 2017-04-01 11:00:21 -0300 | [diff] [blame] | 171 | /* Account for possibly-removed options */ |
| 172 | if (unlikely(len > icsk->icsk_ack.rcv_mss + |
| 173 | MAX_TCP_OPTION_SPACE)) |
| 174 | tcp_gro_dev_warn(sk, skb, len); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 175 | } else { |
| 176 | /* Otherwise, we make more careful check taking into account, |
| 177 | * that SACKs block is variable. |
| 178 | * |
| 179 | * "len" is invariant segment length, including TCP header. |
| 180 | */ |
Arnaldo Carvalho de Melo | 9c70220 | 2007-04-25 18:04:18 -0700 | [diff] [blame] | 181 | len += skb->data - skb_transport_header(skb); |
William Allen Simpson | bee7ca9 | 2009-11-10 09:51:18 +0000 | [diff] [blame] | 182 | if (len >= TCP_MSS_DEFAULT + sizeof(struct tcphdr) || |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 183 | /* If PSH is not set, packet should be |
| 184 | * full sized, provided peer TCP is not badly broken. |
| 185 | * This observation (if it is correct 8)) allows |
| 186 | * to handle super-low mtu links fairly. |
| 187 | */ |
| 188 | (len >= TCP_MIN_MSS + sizeof(struct tcphdr) && |
Arnaldo Carvalho de Melo | aa8223c | 2007-04-10 21:04:22 -0700 | [diff] [blame] | 189 | !(tcp_flag_word(tcp_hdr(skb)) & TCP_REMNANT))) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 190 | /* Subtract also invariant (if peer is RFC compliant), |
| 191 | * tcp header plus fixed timestamp option length. |
| 192 | * Resulting "len" is MSS free of SACK jitter. |
| 193 | */ |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 194 | len -= tcp_sk(sk)->tcp_header_len; |
| 195 | icsk->icsk_ack.last_seg_size = len; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 196 | if (len == lss) { |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 197 | icsk->icsk_ack.rcv_mss = len; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 198 | return; |
| 199 | } |
| 200 | } |
Alexey Kuznetsov | 1ef9696 | 2006-09-19 12:52:50 -0700 | [diff] [blame] | 201 | if (icsk->icsk_ack.pending & ICSK_ACK_PUSHED) |
| 202 | icsk->icsk_ack.pending |= ICSK_ACK_PUSHED2; |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 203 | icsk->icsk_ack.pending |= ICSK_ACK_PUSHED; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 204 | } |
| 205 | } |
| 206 | |
Eric Dumazet | 9a9c9b5 | 2018-05-21 15:08:56 -0700 | [diff] [blame] | 207 | static void tcp_incr_quickack(struct sock *sk, unsigned int max_quickacks) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 208 | { |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 209 | struct inet_connection_sock *icsk = inet_csk(sk); |
Eric Dumazet | 95c9617 | 2012-04-15 05:58:06 +0000 | [diff] [blame] | 210 | unsigned int quickacks = tcp_sk(sk)->rcv_wnd / (2 * icsk->icsk_ack.rcv_mss); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 211 | |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 212 | if (quickacks == 0) |
| 213 | quickacks = 2; |
Eric Dumazet | 9a9c9b5 | 2018-05-21 15:08:56 -0700 | [diff] [blame] | 214 | quickacks = min(quickacks, max_quickacks); |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 215 | if (quickacks > icsk->icsk_ack.quick) |
Eric Dumazet | 9a9c9b5 | 2018-05-21 15:08:56 -0700 | [diff] [blame] | 216 | icsk->icsk_ack.quick = quickacks; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 217 | } |
| 218 | |
Yuchung Cheng | a0496ef2 | 2018-07-18 13:56:36 -0700 | [diff] [blame] | 219 | void tcp_enter_quickack_mode(struct sock *sk, unsigned int max_quickacks) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 220 | { |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 221 | struct inet_connection_sock *icsk = inet_csk(sk); |
Eric Dumazet | 9a9c9b5 | 2018-05-21 15:08:56 -0700 | [diff] [blame] | 222 | |
| 223 | tcp_incr_quickack(sk, max_quickacks); |
Wei Wang | 31954cd | 2019-01-25 10:53:19 -0800 | [diff] [blame] | 224 | inet_csk_exit_pingpong_mode(sk); |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 225 | icsk->icsk_ack.ato = TCP_ATO_MIN; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 226 | } |
Yuchung Cheng | a0496ef2 | 2018-07-18 13:56:36 -0700 | [diff] [blame] | 227 | EXPORT_SYMBOL(tcp_enter_quickack_mode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 228 | |
| 229 | /* Send ACKs quickly, if "quick" count is not exhausted |
| 230 | * and the session is not interactive. |
| 231 | */ |
| 232 | |
Jon Maxwell | 2251ae4 | 2015-07-08 10:12:28 +1000 | [diff] [blame] | 233 | static bool tcp_in_quickack_mode(struct sock *sk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 234 | { |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 235 | const struct inet_connection_sock *icsk = inet_csk(sk); |
Jon Maxwell | 2251ae4 | 2015-07-08 10:12:28 +1000 | [diff] [blame] | 236 | const struct dst_entry *dst = __sk_dst_get(sk); |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 237 | |
Jon Maxwell | 2251ae4 | 2015-07-08 10:12:28 +1000 | [diff] [blame] | 238 | return (dst && dst_metric(dst, RTAX_QUICKACK)) || |
Wei Wang | 31954cd | 2019-01-25 10:53:19 -0800 | [diff] [blame] | 239 | (icsk->icsk_ack.quick && !inet_csk_in_pingpong_mode(sk)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 240 | } |
| 241 | |
Florian Westphal | 735d383 | 2014-09-29 13:08:30 +0200 | [diff] [blame] | 242 | static void tcp_ecn_queue_cwr(struct tcp_sock *tp) |
Ilpo Järvinen | bdf1ee5 | 2007-05-27 02:04:16 -0700 | [diff] [blame] | 243 | { |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 244 | if (tp->ecn_flags & TCP_ECN_OK) |
Ilpo Järvinen | bdf1ee5 | 2007-05-27 02:04:16 -0700 | [diff] [blame] | 245 | tp->ecn_flags |= TCP_ECN_QUEUE_CWR; |
| 246 | } |
| 247 | |
Yuchung Cheng | fd2123a | 2018-08-09 09:38:12 -0700 | [diff] [blame] | 248 | static void tcp_ecn_accept_cwr(struct sock *sk, const struct sk_buff *skb) |
Ilpo Järvinen | bdf1ee5 | 2007-05-27 02:04:16 -0700 | [diff] [blame] | 249 | { |
Lawrence Brakmo | 9aee400 | 2018-07-23 17:49:39 -0700 | [diff] [blame] | 250 | if (tcp_hdr(skb)->cwr) { |
Yuchung Cheng | fd2123a | 2018-08-09 09:38:12 -0700 | [diff] [blame] | 251 | tcp_sk(sk)->ecn_flags &= ~TCP_ECN_DEMAND_CWR; |
Lawrence Brakmo | 9aee400 | 2018-07-23 17:49:39 -0700 | [diff] [blame] | 252 | |
| 253 | /* If the sender is telling us it has entered CWR, then its |
| 254 | * cwnd may be very low (even just 1 packet), so we should ACK |
| 255 | * immediately. |
| 256 | */ |
Yuchung Cheng | fd2123a | 2018-08-09 09:38:12 -0700 | [diff] [blame] | 257 | inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_NOW; |
Lawrence Brakmo | 9aee400 | 2018-07-23 17:49:39 -0700 | [diff] [blame] | 258 | } |
Ilpo Järvinen | bdf1ee5 | 2007-05-27 02:04:16 -0700 | [diff] [blame] | 259 | } |
| 260 | |
Florian Westphal | 735d383 | 2014-09-29 13:08:30 +0200 | [diff] [blame] | 261 | static void tcp_ecn_withdraw_cwr(struct tcp_sock *tp) |
Ilpo Järvinen | bdf1ee5 | 2007-05-27 02:04:16 -0700 | [diff] [blame] | 262 | { |
| 263 | tp->ecn_flags &= ~TCP_ECN_DEMAND_CWR; |
| 264 | } |
| 265 | |
Yousuk Seung | f4c9f85 | 2018-06-04 15:29:51 -0700 | [diff] [blame] | 266 | static void __tcp_ecn_check_ce(struct sock *sk, const struct sk_buff *skb) |
Ilpo Järvinen | bdf1ee5 | 2007-05-27 02:04:16 -0700 | [diff] [blame] | 267 | { |
Yousuk Seung | f4c9f85 | 2018-06-04 15:29:51 -0700 | [diff] [blame] | 268 | struct tcp_sock *tp = tcp_sk(sk); |
| 269 | |
Eric Dumazet | b82d1bb | 2011-09-27 02:20:08 -0400 | [diff] [blame] | 270 | switch (TCP_SKB_CB(skb)->ip_dsfield & INET_ECN_MASK) { |
Eric Dumazet | 7a269ff | 2011-09-22 20:02:19 +0000 | [diff] [blame] | 271 | case INET_ECN_NOT_ECT: |
Ilpo Järvinen | bdf1ee5 | 2007-05-27 02:04:16 -0700 | [diff] [blame] | 272 | /* Funny extension: if ECT is not set on a segment, |
Eric Dumazet | 7a269ff | 2011-09-22 20:02:19 +0000 | [diff] [blame] | 273 | * and we already seen ECT on a previous segment, |
| 274 | * it is probably a retransmit. |
| 275 | */ |
| 276 | if (tp->ecn_flags & TCP_ECN_SEEN) |
Eric Dumazet | 15ecbe9 | 2018-06-27 08:47:21 -0700 | [diff] [blame] | 277 | tcp_enter_quickack_mode(sk, 2); |
Eric Dumazet | 7a269ff | 2011-09-22 20:02:19 +0000 | [diff] [blame] | 278 | break; |
| 279 | case INET_ECN_CE: |
Yousuk Seung | f4c9f85 | 2018-06-04 15:29:51 -0700 | [diff] [blame] | 280 | if (tcp_ca_needs_ecn(sk)) |
| 281 | tcp_ca_event(sk, CA_EVENT_ECN_IS_CE); |
Florian Westphal | 9890092 | 2014-09-26 22:37:35 +0200 | [diff] [blame] | 282 | |
Eric Dumazet | aae06bf | 2012-08-06 11:04:43 +0000 | [diff] [blame] | 283 | if (!(tp->ecn_flags & TCP_ECN_DEMAND_CWR)) { |
| 284 | /* Better not delay acks, sender can have a very low cwnd */ |
Eric Dumazet | 15ecbe9 | 2018-06-27 08:47:21 -0700 | [diff] [blame] | 285 | tcp_enter_quickack_mode(sk, 2); |
Eric Dumazet | aae06bf | 2012-08-06 11:04:43 +0000 | [diff] [blame] | 286 | tp->ecn_flags |= TCP_ECN_DEMAND_CWR; |
| 287 | } |
Eric Dumazet | 7a269ff | 2011-09-22 20:02:19 +0000 | [diff] [blame] | 288 | tp->ecn_flags |= TCP_ECN_SEEN; |
Florian Westphal | 9890092 | 2014-09-26 22:37:35 +0200 | [diff] [blame] | 289 | break; |
| 290 | default: |
Yousuk Seung | f4c9f85 | 2018-06-04 15:29:51 -0700 | [diff] [blame] | 291 | if (tcp_ca_needs_ecn(sk)) |
| 292 | tcp_ca_event(sk, CA_EVENT_ECN_NO_CE); |
Florian Westphal | 9890092 | 2014-09-26 22:37:35 +0200 | [diff] [blame] | 293 | tp->ecn_flags |= TCP_ECN_SEEN; |
| 294 | break; |
Ilpo Järvinen | bdf1ee5 | 2007-05-27 02:04:16 -0700 | [diff] [blame] | 295 | } |
| 296 | } |
| 297 | |
Yousuk Seung | f4c9f85 | 2018-06-04 15:29:51 -0700 | [diff] [blame] | 298 | static void tcp_ecn_check_ce(struct sock *sk, const struct sk_buff *skb) |
Florian Westphal | 735d383 | 2014-09-29 13:08:30 +0200 | [diff] [blame] | 299 | { |
Yousuk Seung | f4c9f85 | 2018-06-04 15:29:51 -0700 | [diff] [blame] | 300 | if (tcp_sk(sk)->ecn_flags & TCP_ECN_OK) |
| 301 | __tcp_ecn_check_ce(sk, skb); |
Florian Westphal | 735d383 | 2014-09-29 13:08:30 +0200 | [diff] [blame] | 302 | } |
| 303 | |
| 304 | static void tcp_ecn_rcv_synack(struct tcp_sock *tp, const struct tcphdr *th) |
Ilpo Järvinen | bdf1ee5 | 2007-05-27 02:04:16 -0700 | [diff] [blame] | 305 | { |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 306 | if ((tp->ecn_flags & TCP_ECN_OK) && (!th->ece || th->cwr)) |
Ilpo Järvinen | bdf1ee5 | 2007-05-27 02:04:16 -0700 | [diff] [blame] | 307 | tp->ecn_flags &= ~TCP_ECN_OK; |
| 308 | } |
| 309 | |
Florian Westphal | 735d383 | 2014-09-29 13:08:30 +0200 | [diff] [blame] | 310 | static void tcp_ecn_rcv_syn(struct tcp_sock *tp, const struct tcphdr *th) |
Ilpo Järvinen | bdf1ee5 | 2007-05-27 02:04:16 -0700 | [diff] [blame] | 311 | { |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 312 | if ((tp->ecn_flags & TCP_ECN_OK) && (!th->ece || !th->cwr)) |
Ilpo Järvinen | bdf1ee5 | 2007-05-27 02:04:16 -0700 | [diff] [blame] | 313 | tp->ecn_flags &= ~TCP_ECN_OK; |
| 314 | } |
| 315 | |
Florian Westphal | 735d383 | 2014-09-29 13:08:30 +0200 | [diff] [blame] | 316 | static bool tcp_ecn_rcv_ecn_echo(const struct tcp_sock *tp, const struct tcphdr *th) |
Ilpo Järvinen | bdf1ee5 | 2007-05-27 02:04:16 -0700 | [diff] [blame] | 317 | { |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 318 | if (th->ece && !th->syn && (tp->ecn_flags & TCP_ECN_OK)) |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 319 | return true; |
| 320 | return false; |
Ilpo Järvinen | bdf1ee5 | 2007-05-27 02:04:16 -0700 | [diff] [blame] | 321 | } |
| 322 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 323 | /* Buffer size and advertised window tuning. |
| 324 | * |
| 325 | * 1. Tuning sk->sk_sndbuf, when connection enters established state. |
| 326 | */ |
| 327 | |
Eric Dumazet | 6ae7053 | 2013-10-01 10:23:44 -0700 | [diff] [blame] | 328 | static void tcp_sndbuf_expand(struct sock *sk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 329 | { |
Eric Dumazet | 6ae7053 | 2013-10-01 10:23:44 -0700 | [diff] [blame] | 330 | const struct tcp_sock *tp = tcp_sk(sk); |
Yuchung Cheng | 77bfc17 | 2016-09-19 23:39:20 -0400 | [diff] [blame] | 331 | const struct tcp_congestion_ops *ca_ops = inet_csk(sk)->icsk_ca_ops; |
Eric Dumazet | 6ae7053 | 2013-10-01 10:23:44 -0700 | [diff] [blame] | 332 | int sndmem, per_mss; |
| 333 | u32 nr_segs; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 334 | |
Eric Dumazet | 6ae7053 | 2013-10-01 10:23:44 -0700 | [diff] [blame] | 335 | /* Worst case is non GSO/TSO : each frame consumes one skb |
| 336 | * and skb->head is kmalloced using power of two area of memory |
| 337 | */ |
| 338 | per_mss = max_t(u32, tp->rx_opt.mss_clamp, tp->mss_cache) + |
| 339 | MAX_TCP_HEADER + |
| 340 | SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); |
| 341 | |
| 342 | per_mss = roundup_pow_of_two(per_mss) + |
| 343 | SKB_DATA_ALIGN(sizeof(struct sk_buff)); |
| 344 | |
| 345 | nr_segs = max_t(u32, TCP_INIT_CWND, tp->snd_cwnd); |
| 346 | nr_segs = max_t(u32, nr_segs, tp->reordering + 1); |
| 347 | |
| 348 | /* Fast Recovery (RFC 5681 3.2) : |
| 349 | * Cubic needs 1.7 factor, rounded to 2 to include |
Linus Torvalds | a9a0884 | 2018-02-11 14:34:03 -0800 | [diff] [blame] | 350 | * extra cushion (application might react slowly to EPOLLOUT) |
Eric Dumazet | 6ae7053 | 2013-10-01 10:23:44 -0700 | [diff] [blame] | 351 | */ |
Yuchung Cheng | 77bfc17 | 2016-09-19 23:39:20 -0400 | [diff] [blame] | 352 | sndmem = ca_ops->sndbuf_expand ? ca_ops->sndbuf_expand(sk) : 2; |
| 353 | sndmem *= nr_segs * per_mss; |
Eric Dumazet | 6ae7053 | 2013-10-01 10:23:44 -0700 | [diff] [blame] | 354 | |
Eric Dumazet | 06a59ec | 2011-10-13 18:24:42 +0000 | [diff] [blame] | 355 | if (sk->sk_sndbuf < sndmem) |
Eric Dumazet | 356d183 | 2017-11-07 00:29:28 -0800 | [diff] [blame] | 356 | sk->sk_sndbuf = min(sndmem, sock_net(sk)->ipv4.sysctl_tcp_wmem[2]); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 357 | } |
| 358 | |
| 359 | /* 2. Tuning advertised window (window_clamp, rcv_ssthresh) |
| 360 | * |
| 361 | * All tcp_full_space() is split to two parts: "network" buffer, allocated |
| 362 | * forward and advertised in receiver window (tp->rcv_wnd) and |
| 363 | * "application buffer", required to isolate scheduling/application |
| 364 | * latencies from network. |
| 365 | * window_clamp is maximal advertised window. It can be less than |
| 366 | * tcp_full_space(), in this case tcp_full_space() - window_clamp |
| 367 | * is reserved for "application" buffer. The less window_clamp is |
| 368 | * the smoother our behaviour from viewpoint of network, but the lower |
| 369 | * throughput and the higher sensitivity of the connection to losses. 8) |
| 370 | * |
| 371 | * rcv_ssthresh is more strict window_clamp used at "slow start" |
| 372 | * phase to predict further behaviour of this connection. |
| 373 | * It is used for two goals: |
| 374 | * - to enforce header prediction at sender, even when application |
| 375 | * requires some significant "application buffer". It is check #1. |
| 376 | * - to prevent pruning of receive queue because of misprediction |
| 377 | * of receiver window. Check #2. |
| 378 | * |
| 379 | * The scheme does not work when sender sends good segments opening |
Stephen Hemminger | caa20d9a | 2005-11-10 17:13:47 -0800 | [diff] [blame] | 380 | * window and then starts to feed us spaghetti. But it should work |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 381 | * in common situations. Otherwise, we have to rely on queue collapsing. |
| 382 | */ |
| 383 | |
| 384 | /* Slow part of check#2. */ |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 385 | static int __tcp_grow_window(const struct sock *sk, const struct sk_buff *skb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 386 | { |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 387 | struct tcp_sock *tp = tcp_sk(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 388 | /* Optimize this! */ |
Eric Dumazet | 94f0893 | 2017-10-26 21:55:09 -0700 | [diff] [blame] | 389 | int truesize = tcp_win_from_space(sk, skb->truesize) >> 1; |
Eric Dumazet | 356d183 | 2017-11-07 00:29:28 -0800 | [diff] [blame] | 390 | int window = tcp_win_from_space(sk, sock_net(sk)->ipv4.sysctl_tcp_rmem[2]) >> 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 391 | |
| 392 | while (tp->rcv_ssthresh <= window) { |
| 393 | if (truesize <= skb->len) |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 394 | return 2 * inet_csk(sk)->icsk_ack.rcv_mss; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 395 | |
| 396 | truesize >>= 1; |
| 397 | window >>= 1; |
| 398 | } |
| 399 | return 0; |
| 400 | } |
| 401 | |
Eric Dumazet | cf533ea | 2011-10-21 05:22:42 -0400 | [diff] [blame] | 402 | static void tcp_grow_window(struct sock *sk, const struct sk_buff *skb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 403 | { |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 404 | struct tcp_sock *tp = tcp_sk(sk); |
| 405 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 406 | /* Check #1 */ |
| 407 | if (tp->rcv_ssthresh < tp->window_clamp && |
| 408 | (int)tp->rcv_ssthresh < tcp_space(sk) && |
Eric Dumazet | b8da51e | 2015-05-15 12:39:27 -0700 | [diff] [blame] | 409 | !tcp_under_memory_pressure(sk)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 410 | int incr; |
| 411 | |
| 412 | /* Check #2. Increase window, if skb with such overhead |
| 413 | * will fit to rcvbuf in future. |
| 414 | */ |
Eric Dumazet | 94f0893 | 2017-10-26 21:55:09 -0700 | [diff] [blame] | 415 | if (tcp_win_from_space(sk, skb->truesize) <= skb->len) |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 416 | incr = 2 * tp->advmss; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 417 | else |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 418 | incr = __tcp_grow_window(sk, skb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 419 | |
| 420 | if (incr) { |
Eric Dumazet | 4d846f0 | 2012-04-16 23:28:07 +0000 | [diff] [blame] | 421 | incr = max_t(int, incr, 2 * skb->len); |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 422 | tp->rcv_ssthresh = min(tp->rcv_ssthresh + incr, |
| 423 | tp->window_clamp); |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 424 | inet_csk(sk)->icsk_ack.quick |= 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 425 | } |
| 426 | } |
| 427 | } |
| 428 | |
Yuchung Cheng | a337531 | 2018-09-27 11:21:19 -0700 | [diff] [blame] | 429 | /* 3. Try to fixup all. It is made immediately after connection enters |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 430 | * established state. |
| 431 | */ |
Jerry Chu | 1046716 | 2012-08-31 12:29:11 +0000 | [diff] [blame] | 432 | void tcp_init_buffer_space(struct sock *sk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 433 | { |
Eric Dumazet | 0c12654 | 2017-10-26 21:55:08 -0700 | [diff] [blame] | 434 | int tcp_app_win = sock_net(sk)->ipv4.sysctl_tcp_app_win; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 435 | struct tcp_sock *tp = tcp_sk(sk); |
| 436 | int maxwin; |
| 437 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 438 | if (!(sk->sk_userlocks & SOCK_SNDBUF_LOCK)) |
Eric Dumazet | 6ae7053 | 2013-10-01 10:23:44 -0700 | [diff] [blame] | 439 | tcp_sndbuf_expand(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 440 | |
Yuchung Cheng | 041a14d | 2018-10-01 15:42:32 -0700 | [diff] [blame] | 441 | tp->rcvq_space.space = min_t(u32, tp->rcv_wnd, TCP_INIT_CWND * tp->advmss); |
Eric Dumazet | 9a568de | 2017-05-16 14:00:14 -0700 | [diff] [blame] | 442 | tcp_mstamp_refresh(tp); |
Eric Dumazet | 645f4c6 | 2017-04-25 10:15:41 -0700 | [diff] [blame] | 443 | tp->rcvq_space.time = tp->tcp_mstamp; |
Eric Dumazet | b0983d3 | 2013-09-20 13:56:58 -0700 | [diff] [blame] | 444 | tp->rcvq_space.seq = tp->copied_seq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 445 | |
| 446 | maxwin = tcp_full_space(sk); |
| 447 | |
| 448 | if (tp->window_clamp >= maxwin) { |
| 449 | tp->window_clamp = maxwin; |
| 450 | |
Eric Dumazet | 0c12654 | 2017-10-26 21:55:08 -0700 | [diff] [blame] | 451 | if (tcp_app_win && maxwin > 4 * tp->advmss) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 452 | tp->window_clamp = max(maxwin - |
Eric Dumazet | 0c12654 | 2017-10-26 21:55:08 -0700 | [diff] [blame] | 453 | (maxwin >> tcp_app_win), |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 454 | 4 * tp->advmss); |
| 455 | } |
| 456 | |
| 457 | /* Force reservation of one segment. */ |
Eric Dumazet | 0c12654 | 2017-10-26 21:55:08 -0700 | [diff] [blame] | 458 | if (tcp_app_win && |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 459 | tp->window_clamp > 2 * tp->advmss && |
| 460 | tp->window_clamp + tp->advmss > maxwin) |
| 461 | tp->window_clamp = max(2 * tp->advmss, maxwin - tp->advmss); |
| 462 | |
| 463 | tp->rcv_ssthresh = min(tp->rcv_ssthresh, tp->window_clamp); |
Eric Dumazet | c2203cf | 2017-05-16 14:00:04 -0700 | [diff] [blame] | 464 | tp->snd_cwnd_stamp = tcp_jiffies32; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 465 | } |
| 466 | |
Yuchung Cheng | a337531 | 2018-09-27 11:21:19 -0700 | [diff] [blame] | 467 | /* 4. Recalculate window clamp after socket hit its memory bounds. */ |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 468 | static void tcp_clamp_window(struct sock *sk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 469 | { |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 470 | struct tcp_sock *tp = tcp_sk(sk); |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 471 | struct inet_connection_sock *icsk = inet_csk(sk); |
Eric Dumazet | 356d183 | 2017-11-07 00:29:28 -0800 | [diff] [blame] | 472 | struct net *net = sock_net(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 473 | |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 474 | icsk->icsk_ack.quick = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 475 | |
Eric Dumazet | 356d183 | 2017-11-07 00:29:28 -0800 | [diff] [blame] | 476 | if (sk->sk_rcvbuf < net->ipv4.sysctl_tcp_rmem[2] && |
John Heffner | 326f36e | 2005-11-10 17:11:48 -0800 | [diff] [blame] | 477 | !(sk->sk_userlocks & SOCK_RCVBUF_LOCK) && |
Eric Dumazet | b8da51e | 2015-05-15 12:39:27 -0700 | [diff] [blame] | 478 | !tcp_under_memory_pressure(sk) && |
Glauber Costa | 180d8cd | 2011-12-11 21:47:02 +0000 | [diff] [blame] | 479 | sk_memory_allocated(sk) < sk_prot_mem_limits(sk, 0)) { |
John Heffner | 326f36e | 2005-11-10 17:11:48 -0800 | [diff] [blame] | 480 | sk->sk_rcvbuf = min(atomic_read(&sk->sk_rmem_alloc), |
Eric Dumazet | 356d183 | 2017-11-07 00:29:28 -0800 | [diff] [blame] | 481 | net->ipv4.sysctl_tcp_rmem[2]); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 482 | } |
John Heffner | 326f36e | 2005-11-10 17:11:48 -0800 | [diff] [blame] | 483 | if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf) |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 484 | tp->rcv_ssthresh = min(tp->window_clamp, 2U * tp->advmss); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 485 | } |
| 486 | |
Stephen Hemminger | 40efc6f | 2006-01-03 16:03:49 -0800 | [diff] [blame] | 487 | /* Initialize RCV_MSS value. |
| 488 | * RCV_MSS is an our guess about MSS used by the peer. |
| 489 | * We haven't any direct information about the MSS. |
| 490 | * It's better to underestimate the RCV_MSS rather than overestimate. |
| 491 | * Overestimations make us ACKing less frequently than needed. |
| 492 | * Underestimations are more easy to detect and fix by tcp_measure_rcv_mss(). |
| 493 | */ |
| 494 | void tcp_initialize_rcv_mss(struct sock *sk) |
| 495 | { |
Eric Dumazet | cf533ea | 2011-10-21 05:22:42 -0400 | [diff] [blame] | 496 | const struct tcp_sock *tp = tcp_sk(sk); |
Stephen Hemminger | 40efc6f | 2006-01-03 16:03:49 -0800 | [diff] [blame] | 497 | unsigned int hint = min_t(unsigned int, tp->advmss, tp->mss_cache); |
| 498 | |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 499 | hint = min(hint, tp->rcv_wnd / 2); |
William Allen Simpson | bee7ca9 | 2009-11-10 09:51:18 +0000 | [diff] [blame] | 500 | hint = min(hint, TCP_MSS_DEFAULT); |
Stephen Hemminger | 40efc6f | 2006-01-03 16:03:49 -0800 | [diff] [blame] | 501 | hint = max(hint, TCP_MIN_MSS); |
| 502 | |
| 503 | inet_csk(sk)->icsk_ack.rcv_mss = hint; |
| 504 | } |
Eric Dumazet | 4bc2f18 | 2010-07-09 21:22:10 +0000 | [diff] [blame] | 505 | EXPORT_SYMBOL(tcp_initialize_rcv_mss); |
Stephen Hemminger | 40efc6f | 2006-01-03 16:03:49 -0800 | [diff] [blame] | 506 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 507 | /* Receiver "autotuning" code. |
| 508 | * |
| 509 | * The algorithm for RTT estimation w/o timestamps is based on |
| 510 | * Dynamic Right-Sizing (DRS) by Wu Feng and Mike Fisk of LANL. |
Justin P. Mattock | 631dd1a | 2010-10-18 11:03:14 +0200 | [diff] [blame] | 511 | * <http://public.lanl.gov/radiant/pubs.html#DRS> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 512 | * |
| 513 | * More detail on this code can be found at |
Justin P. Mattock | 631dd1a | 2010-10-18 11:03:14 +0200 | [diff] [blame] | 514 | * <http://staff.psc.edu/jheffner/>, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 515 | * though this reference is out of date. A new paper |
| 516 | * is pending. |
| 517 | */ |
| 518 | static void tcp_rcv_rtt_update(struct tcp_sock *tp, u32 sample, int win_dep) |
| 519 | { |
Eric Dumazet | 645f4c6 | 2017-04-25 10:15:41 -0700 | [diff] [blame] | 520 | u32 new_sample = tp->rcv_rtt_est.rtt_us; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 521 | long m = sample; |
| 522 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 523 | if (new_sample != 0) { |
| 524 | /* If we sample in larger samples in the non-timestamp |
| 525 | * case, we could grossly overestimate the RTT especially |
| 526 | * with chatty applications or bulk transfer apps which |
| 527 | * are stalled on filesystem I/O. |
| 528 | * |
| 529 | * Also, since we are only going for a minimum in the |
Stephen Hemminger | 31f3426 | 2005-11-15 15:17:10 -0800 | [diff] [blame] | 530 | * non-timestamp case, we do not smooth things out |
Stephen Hemminger | caa20d9a | 2005-11-10 17:13:47 -0800 | [diff] [blame] | 531 | * else with timestamps disabled convergence takes too |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 532 | * long. |
| 533 | */ |
| 534 | if (!win_dep) { |
| 535 | m -= (new_sample >> 3); |
| 536 | new_sample += m; |
Neal Cardwell | 18a223e | 2012-04-10 07:59:20 +0000 | [diff] [blame] | 537 | } else { |
| 538 | m <<= 3; |
| 539 | if (m < new_sample) |
| 540 | new_sample = m; |
| 541 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 542 | } else { |
Stephen Hemminger | caa20d9a | 2005-11-10 17:13:47 -0800 | [diff] [blame] | 543 | /* No previous measure. */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 544 | new_sample = m << 3; |
| 545 | } |
| 546 | |
Eric Dumazet | 645f4c6 | 2017-04-25 10:15:41 -0700 | [diff] [blame] | 547 | tp->rcv_rtt_est.rtt_us = new_sample; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 548 | } |
| 549 | |
| 550 | static inline void tcp_rcv_rtt_measure(struct tcp_sock *tp) |
| 551 | { |
Eric Dumazet | 645f4c6 | 2017-04-25 10:15:41 -0700 | [diff] [blame] | 552 | u32 delta_us; |
| 553 | |
Eric Dumazet | 9a568de | 2017-05-16 14:00:14 -0700 | [diff] [blame] | 554 | if (tp->rcv_rtt_est.time == 0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 555 | goto new_measure; |
| 556 | if (before(tp->rcv_nxt, tp->rcv_rtt_est.seq)) |
| 557 | return; |
Eric Dumazet | 9a568de | 2017-05-16 14:00:14 -0700 | [diff] [blame] | 558 | delta_us = tcp_stamp_us_delta(tp->tcp_mstamp, tp->rcv_rtt_est.time); |
Wei Wang | 9ee11bd | 2017-12-12 16:28:58 -0800 | [diff] [blame] | 559 | if (!delta_us) |
| 560 | delta_us = 1; |
Eric Dumazet | 645f4c6 | 2017-04-25 10:15:41 -0700 | [diff] [blame] | 561 | tcp_rcv_rtt_update(tp, delta_us, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 562 | |
| 563 | new_measure: |
| 564 | tp->rcv_rtt_est.seq = tp->rcv_nxt + tp->rcv_wnd; |
Eric Dumazet | 645f4c6 | 2017-04-25 10:15:41 -0700 | [diff] [blame] | 565 | tp->rcv_rtt_est.time = tp->tcp_mstamp; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 566 | } |
| 567 | |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 568 | static inline void tcp_rcv_rtt_measure_ts(struct sock *sk, |
| 569 | const struct sk_buff *skb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 570 | { |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 571 | struct tcp_sock *tp = tcp_sk(sk); |
Eric Dumazet | 9a568de | 2017-05-16 14:00:14 -0700 | [diff] [blame] | 572 | |
Wei Wang | 3f6c65d | 2018-06-19 21:42:50 -0700 | [diff] [blame] | 573 | if (tp->rx_opt.rcv_tsecr == tp->rcv_rtt_last_tsecr) |
| 574 | return; |
| 575 | tp->rcv_rtt_last_tsecr = tp->rx_opt.rcv_tsecr; |
| 576 | |
| 577 | if (TCP_SKB_CB(skb)->end_seq - |
| 578 | TCP_SKB_CB(skb)->seq >= inet_csk(sk)->icsk_ack.rcv_mss) { |
Eric Dumazet | 9a568de | 2017-05-16 14:00:14 -0700 | [diff] [blame] | 579 | u32 delta = tcp_time_stamp(tp) - tp->rx_opt.rcv_tsecr; |
Wei Wang | 9ee11bd | 2017-12-12 16:28:58 -0800 | [diff] [blame] | 580 | u32 delta_us; |
Eric Dumazet | 9a568de | 2017-05-16 14:00:14 -0700 | [diff] [blame] | 581 | |
Eric Dumazet | 9efdda4 | 2018-11-24 09:12:24 -0800 | [diff] [blame] | 582 | if (likely(delta < INT_MAX / (USEC_PER_SEC / TCP_TS_HZ))) { |
| 583 | if (!delta) |
| 584 | delta = 1; |
| 585 | delta_us = delta * (USEC_PER_SEC / TCP_TS_HZ); |
| 586 | tcp_rcv_rtt_update(tp, delta_us, 0); |
| 587 | } |
Eric Dumazet | 9a568de | 2017-05-16 14:00:14 -0700 | [diff] [blame] | 588 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 589 | } |
| 590 | |
| 591 | /* |
| 592 | * This function should be called every time data is copied to user space. |
| 593 | * It calculates the appropriate TCP receive buffer space. |
| 594 | */ |
| 595 | void tcp_rcv_space_adjust(struct sock *sk) |
| 596 | { |
| 597 | struct tcp_sock *tp = tcp_sk(sk); |
Eric Dumazet | 607065b | 2017-12-10 17:55:03 -0800 | [diff] [blame] | 598 | u32 copied; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 599 | int time; |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 600 | |
Yafang Shao | 6163849 | 2018-04-20 23:18:26 +0800 | [diff] [blame] | 601 | trace_tcp_rcv_space_adjust(sk); |
| 602 | |
Eric Dumazet | 8632385 | 2017-12-06 11:08:19 -0800 | [diff] [blame] | 603 | tcp_mstamp_refresh(tp); |
Eric Dumazet | 9a568de | 2017-05-16 14:00:14 -0700 | [diff] [blame] | 604 | time = tcp_stamp_us_delta(tp->tcp_mstamp, tp->rcvq_space.time); |
Eric Dumazet | 645f4c6 | 2017-04-25 10:15:41 -0700 | [diff] [blame] | 605 | if (time < (tp->rcv_rtt_est.rtt_us >> 3) || tp->rcv_rtt_est.rtt_us == 0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 606 | return; |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 607 | |
Eric Dumazet | b0983d3 | 2013-09-20 13:56:58 -0700 | [diff] [blame] | 608 | /* Number of bytes copied to user in last RTT */ |
| 609 | copied = tp->copied_seq - tp->rcvq_space.seq; |
| 610 | if (copied <= tp->rcvq_space.space) |
| 611 | goto new_measure; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 612 | |
Eric Dumazet | b0983d3 | 2013-09-20 13:56:58 -0700 | [diff] [blame] | 613 | /* A bit of theory : |
| 614 | * copied = bytes received in previous RTT, our base window |
| 615 | * To cope with packet losses, we need a 2x factor |
| 616 | * To cope with slow start, and sender growing its cwin by 100 % |
| 617 | * every RTT, we need a 4x factor, because the ACK we are sending |
| 618 | * now is for the next RTT, not the current one : |
| 619 | * <prev RTT . ><current RTT .. ><next RTT .... > |
| 620 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 621 | |
Eric Dumazet | 4540c0c | 2017-10-27 07:47:22 -0700 | [diff] [blame] | 622 | if (sock_net(sk)->ipv4.sysctl_tcp_moderate_rcvbuf && |
Eric Dumazet | b0983d3 | 2013-09-20 13:56:58 -0700 | [diff] [blame] | 623 | !(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) { |
Eric Dumazet | 607065b | 2017-12-10 17:55:03 -0800 | [diff] [blame] | 624 | int rcvmem, rcvbuf; |
Eric Dumazet | c3916ad | 2017-12-10 17:55:04 -0800 | [diff] [blame] | 625 | u64 rcvwin, grow; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 626 | |
Eric Dumazet | b0983d3 | 2013-09-20 13:56:58 -0700 | [diff] [blame] | 627 | /* minimal window to cope with packet losses, assuming |
| 628 | * steady state. Add some cushion because of small variations. |
| 629 | */ |
Eric Dumazet | 607065b | 2017-12-10 17:55:03 -0800 | [diff] [blame] | 630 | rcvwin = ((u64)copied << 1) + 16 * tp->advmss; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 631 | |
Eric Dumazet | c3916ad | 2017-12-10 17:55:04 -0800 | [diff] [blame] | 632 | /* Accommodate for sender rate increase (eg. slow start) */ |
| 633 | grow = rcvwin * (copied - tp->rcvq_space.space); |
| 634 | do_div(grow, tp->rcvq_space.space); |
| 635 | rcvwin += (grow << 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 636 | |
Eric Dumazet | b0983d3 | 2013-09-20 13:56:58 -0700 | [diff] [blame] | 637 | rcvmem = SKB_TRUESIZE(tp->advmss + MAX_TCP_HEADER); |
Eric Dumazet | 94f0893 | 2017-10-26 21:55:09 -0700 | [diff] [blame] | 638 | while (tcp_win_from_space(sk, rcvmem) < tp->advmss) |
Eric Dumazet | b0983d3 | 2013-09-20 13:56:58 -0700 | [diff] [blame] | 639 | rcvmem += 128; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 640 | |
Eric Dumazet | 607065b | 2017-12-10 17:55:03 -0800 | [diff] [blame] | 641 | do_div(rcvwin, tp->advmss); |
| 642 | rcvbuf = min_t(u64, rcvwin * rcvmem, |
| 643 | sock_net(sk)->ipv4.sysctl_tcp_rmem[2]); |
Eric Dumazet | b0983d3 | 2013-09-20 13:56:58 -0700 | [diff] [blame] | 644 | if (rcvbuf > sk->sk_rcvbuf) { |
| 645 | sk->sk_rcvbuf = rcvbuf; |
| 646 | |
| 647 | /* Make the window clamp follow along. */ |
Eric Dumazet | 02db557 | 2017-12-10 17:55:02 -0800 | [diff] [blame] | 648 | tp->window_clamp = tcp_win_from_space(sk, rcvbuf); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 649 | } |
| 650 | } |
Eric Dumazet | b0983d3 | 2013-09-20 13:56:58 -0700 | [diff] [blame] | 651 | tp->rcvq_space.space = copied; |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 652 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 653 | new_measure: |
| 654 | tp->rcvq_space.seq = tp->copied_seq; |
Eric Dumazet | 645f4c6 | 2017-04-25 10:15:41 -0700 | [diff] [blame] | 655 | tp->rcvq_space.time = tp->tcp_mstamp; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 656 | } |
| 657 | |
| 658 | /* There is something which you must keep in mind when you analyze the |
| 659 | * behavior of the tp->ato delayed ack timeout interval. When a |
| 660 | * connection starts up, we want to ack as quickly as possible. The |
| 661 | * problem is that "good" TCP's do slow start at the beginning of data |
| 662 | * transmission. The means that until we send the first few ACK's the |
| 663 | * sender will sit on his end and only queue most of his data, because |
| 664 | * he can only send snd_cwnd unacked packets at any given time. For |
| 665 | * each ACK we send, he increments snd_cwnd and transmits more of his |
| 666 | * queue. -DaveM |
| 667 | */ |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 668 | static void tcp_event_data_recv(struct sock *sk, struct sk_buff *skb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 669 | { |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 670 | struct tcp_sock *tp = tcp_sk(sk); |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 671 | struct inet_connection_sock *icsk = inet_csk(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 672 | u32 now; |
| 673 | |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 674 | inet_csk_schedule_ack(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 675 | |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 676 | tcp_measure_rcv_mss(sk, skb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 677 | |
| 678 | tcp_rcv_rtt_measure(tp); |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 679 | |
Eric Dumazet | 70eabf0 | 2017-05-16 14:00:07 -0700 | [diff] [blame] | 680 | now = tcp_jiffies32; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 681 | |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 682 | if (!icsk->icsk_ack.ato) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 683 | /* The _first_ data packet received, initialize |
| 684 | * delayed ACK engine. |
| 685 | */ |
Eric Dumazet | 9a9c9b5 | 2018-05-21 15:08:56 -0700 | [diff] [blame] | 686 | tcp_incr_quickack(sk, TCP_MAX_QUICKACKS); |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 687 | icsk->icsk_ack.ato = TCP_ATO_MIN; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 688 | } else { |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 689 | int m = now - icsk->icsk_ack.lrcvtime; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 690 | |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 691 | if (m <= TCP_ATO_MIN / 2) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 692 | /* The fastest case is the first. */ |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 693 | icsk->icsk_ack.ato = (icsk->icsk_ack.ato >> 1) + TCP_ATO_MIN / 2; |
| 694 | } else if (m < icsk->icsk_ack.ato) { |
| 695 | icsk->icsk_ack.ato = (icsk->icsk_ack.ato >> 1) + m; |
| 696 | if (icsk->icsk_ack.ato > icsk->icsk_rto) |
| 697 | icsk->icsk_ack.ato = icsk->icsk_rto; |
| 698 | } else if (m > icsk->icsk_rto) { |
Stephen Hemminger | caa20d9a | 2005-11-10 17:13:47 -0800 | [diff] [blame] | 699 | /* Too long gap. Apparently sender failed to |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 700 | * restart window, so that we send ACKs quickly. |
| 701 | */ |
Eric Dumazet | 9a9c9b5 | 2018-05-21 15:08:56 -0700 | [diff] [blame] | 702 | tcp_incr_quickack(sk, TCP_MAX_QUICKACKS); |
Hideo Aoki | 3ab224b | 2007-12-31 00:11:19 -0800 | [diff] [blame] | 703 | sk_mem_reclaim(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 704 | } |
| 705 | } |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 706 | icsk->icsk_ack.lrcvtime = now; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 707 | |
Yousuk Seung | f4c9f85 | 2018-06-04 15:29:51 -0700 | [diff] [blame] | 708 | tcp_ecn_check_ce(sk, skb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 709 | |
| 710 | if (skb->len >= 128) |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 711 | tcp_grow_window(sk, skb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 712 | } |
| 713 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 714 | /* Called to compute a smoothed rtt estimate. The data fed to this |
| 715 | * routine either comes from timestamps, or from segments that were |
| 716 | * known _not_ to have been retransmitted [see Karn/Partridge |
| 717 | * Proceedings SIGCOMM 87]. The algorithm is from the SIGCOMM 88 |
| 718 | * piece by Van Jacobson. |
| 719 | * NOTE: the next three routines used to be one big routine. |
| 720 | * To save cycles in the RFC 1323 implementation it was better to break |
| 721 | * it up into three procedures. -- erics |
| 722 | */ |
Eric Dumazet | 740b0f1 | 2014-02-26 14:02:48 -0800 | [diff] [blame] | 723 | static void tcp_rtt_estimator(struct sock *sk, long mrtt_us) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 724 | { |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 725 | struct tcp_sock *tp = tcp_sk(sk); |
Eric Dumazet | 740b0f1 | 2014-02-26 14:02:48 -0800 | [diff] [blame] | 726 | long m = mrtt_us; /* RTT */ |
| 727 | u32 srtt = tp->srtt_us; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 728 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 729 | /* The following amusing code comes from Jacobson's |
| 730 | * article in SIGCOMM '88. Note that rtt and mdev |
| 731 | * are scaled versions of rtt and mean deviation. |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 732 | * This is designed to be as fast as possible |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 733 | * m stands for "measurement". |
| 734 | * |
| 735 | * On a 1990 paper the rto value is changed to: |
| 736 | * RTO = rtt + 4 * mdev |
| 737 | * |
| 738 | * Funny. This algorithm seems to be very broken. |
| 739 | * These formulae increase RTO, when it should be decreased, increase |
Stephen Hemminger | 31f3426 | 2005-11-15 15:17:10 -0800 | [diff] [blame] | 740 | * too slowly, when it should be increased quickly, decrease too quickly |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 741 | * etc. I guess in BSD RTO takes ONE value, so that it is absolutely |
| 742 | * does not matter how to _calculate_ it. Seems, it was trap |
| 743 | * that VJ failed to avoid. 8) |
| 744 | */ |
Eric Dumazet | 4a5ab4e | 2014-02-06 15:57:10 -0800 | [diff] [blame] | 745 | if (srtt != 0) { |
| 746 | m -= (srtt >> 3); /* m is now error in rtt est */ |
| 747 | srtt += m; /* rtt = 7/8 rtt + 1/8 new */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 748 | if (m < 0) { |
| 749 | m = -m; /* m is now abs(error) */ |
Eric Dumazet | 740b0f1 | 2014-02-26 14:02:48 -0800 | [diff] [blame] | 750 | m -= (tp->mdev_us >> 2); /* similar update on mdev */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 751 | /* This is similar to one of Eifel findings. |
| 752 | * Eifel blocks mdev updates when rtt decreases. |
| 753 | * This solution is a bit different: we use finer gain |
| 754 | * for mdev in this case (alpha*beta). |
| 755 | * Like Eifel it also prevents growth of rto, |
| 756 | * but also it limits too fast rto decreases, |
| 757 | * happening in pure Eifel. |
| 758 | */ |
| 759 | if (m > 0) |
| 760 | m >>= 3; |
| 761 | } else { |
Eric Dumazet | 740b0f1 | 2014-02-26 14:02:48 -0800 | [diff] [blame] | 762 | m -= (tp->mdev_us >> 2); /* similar update on mdev */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 763 | } |
Eric Dumazet | 740b0f1 | 2014-02-26 14:02:48 -0800 | [diff] [blame] | 764 | tp->mdev_us += m; /* mdev = 3/4 mdev + 1/4 new */ |
| 765 | if (tp->mdev_us > tp->mdev_max_us) { |
| 766 | tp->mdev_max_us = tp->mdev_us; |
| 767 | if (tp->mdev_max_us > tp->rttvar_us) |
| 768 | tp->rttvar_us = tp->mdev_max_us; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 769 | } |
| 770 | if (after(tp->snd_una, tp->rtt_seq)) { |
Eric Dumazet | 740b0f1 | 2014-02-26 14:02:48 -0800 | [diff] [blame] | 771 | if (tp->mdev_max_us < tp->rttvar_us) |
| 772 | tp->rttvar_us -= (tp->rttvar_us - tp->mdev_max_us) >> 2; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 773 | tp->rtt_seq = tp->snd_nxt; |
Eric Dumazet | 740b0f1 | 2014-02-26 14:02:48 -0800 | [diff] [blame] | 774 | tp->mdev_max_us = tcp_rto_min_us(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 775 | } |
| 776 | } else { |
| 777 | /* no previous measure. */ |
Eric Dumazet | 4a5ab4e | 2014-02-06 15:57:10 -0800 | [diff] [blame] | 778 | srtt = m << 3; /* take the measured time to be rtt */ |
Eric Dumazet | 740b0f1 | 2014-02-26 14:02:48 -0800 | [diff] [blame] | 779 | tp->mdev_us = m << 1; /* make sure rto = 3*rtt */ |
| 780 | tp->rttvar_us = max(tp->mdev_us, tcp_rto_min_us(sk)); |
| 781 | tp->mdev_max_us = tp->rttvar_us; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 782 | tp->rtt_seq = tp->snd_nxt; |
| 783 | } |
Eric Dumazet | 740b0f1 | 2014-02-26 14:02:48 -0800 | [diff] [blame] | 784 | tp->srtt_us = max(1U, srtt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 785 | } |
| 786 | |
Eric Dumazet | 95bd09e | 2013-08-27 05:46:32 -0700 | [diff] [blame] | 787 | static void tcp_update_pacing_rate(struct sock *sk) |
| 788 | { |
| 789 | const struct tcp_sock *tp = tcp_sk(sk); |
| 790 | u64 rate; |
| 791 | |
| 792 | /* set sk_pacing_rate to 200 % of current rate (mss * cwnd / srtt) */ |
Eric Dumazet | 43e122b | 2015-08-21 17:38:02 -0700 | [diff] [blame] | 793 | rate = (u64)tp->mss_cache * ((USEC_PER_SEC / 100) << 3); |
| 794 | |
| 795 | /* current rate is (cwnd * mss) / srtt |
| 796 | * In Slow Start [1], set sk_pacing_rate to 200 % the current rate. |
| 797 | * In Congestion Avoidance phase, set it to 120 % the current rate. |
| 798 | * |
| 799 | * [1] : Normal Slow Start condition is (tp->snd_cwnd < tp->snd_ssthresh) |
| 800 | * If snd_cwnd >= (tp->snd_ssthresh / 2), we are approaching |
| 801 | * end of slow start and should slow down. |
| 802 | */ |
| 803 | if (tp->snd_cwnd < tp->snd_ssthresh / 2) |
Eric Dumazet | 23a7102a | 2017-10-27 07:47:31 -0700 | [diff] [blame] | 804 | rate *= sock_net(sk)->ipv4.sysctl_tcp_pacing_ss_ratio; |
Eric Dumazet | 43e122b | 2015-08-21 17:38:02 -0700 | [diff] [blame] | 805 | else |
Eric Dumazet | c26e91f | 2017-10-27 07:47:32 -0700 | [diff] [blame] | 806 | rate *= sock_net(sk)->ipv4.sysctl_tcp_pacing_ca_ratio; |
Eric Dumazet | 95bd09e | 2013-08-27 05:46:32 -0700 | [diff] [blame] | 807 | |
| 808 | rate *= max(tp->snd_cwnd, tp->packets_out); |
| 809 | |
Eric Dumazet | 740b0f1 | 2014-02-26 14:02:48 -0800 | [diff] [blame] | 810 | if (likely(tp->srtt_us)) |
| 811 | do_div(rate, tp->srtt_us); |
Eric Dumazet | 95bd09e | 2013-08-27 05:46:32 -0700 | [diff] [blame] | 812 | |
Mark Rutland | a9da6f2 | 2017-10-23 14:07:18 -0700 | [diff] [blame] | 813 | /* WRITE_ONCE() is needed because sch_fq fetches sk_pacing_rate |
Eric Dumazet | ba53742 | 2013-10-09 17:14:52 -0700 | [diff] [blame] | 814 | * without any lock. We want to make sure compiler wont store |
| 815 | * intermediate values in this location. |
| 816 | */ |
Mark Rutland | a9da6f2 | 2017-10-23 14:07:18 -0700 | [diff] [blame] | 817 | WRITE_ONCE(sk->sk_pacing_rate, min_t(u64, rate, |
| 818 | sk->sk_max_pacing_rate)); |
Eric Dumazet | 95bd09e | 2013-08-27 05:46:32 -0700 | [diff] [blame] | 819 | } |
| 820 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 821 | /* Calculate rto without backoff. This is the second half of Van Jacobson's |
| 822 | * routine referred to above. |
| 823 | */ |
stephen hemminger | f7e56a7 | 2013-12-29 11:39:51 -0800 | [diff] [blame] | 824 | static void tcp_set_rto(struct sock *sk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 825 | { |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 826 | const struct tcp_sock *tp = tcp_sk(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 827 | /* Old crap is replaced with new one. 8) |
| 828 | * |
| 829 | * More seriously: |
| 830 | * 1. If rtt variance happened to be less 50msec, it is hallucination. |
| 831 | * It cannot be less due to utterly erratic ACK generation made |
| 832 | * at least by solaris and freebsd. "Erratic ACKs" has _nothing_ |
| 833 | * to do with delayed acks, because at cwnd>2 true delack timeout |
| 834 | * is invisible. Actually, Linux-2.4 also generates erratic |
Stephen Hemminger | caa20d9a | 2005-11-10 17:13:47 -0800 | [diff] [blame] | 835 | * ACKs in some circumstances. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 836 | */ |
Damian Lukowski | f1ecd5d | 2009-08-26 00:16:31 +0000 | [diff] [blame] | 837 | inet_csk(sk)->icsk_rto = __tcp_set_rto(tp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 838 | |
| 839 | /* 2. Fixups made earlier cannot be right. |
| 840 | * If we do not estimate RTO correctly without them, |
| 841 | * all the algo is pure shit and should be replaced |
Stephen Hemminger | caa20d9a | 2005-11-10 17:13:47 -0800 | [diff] [blame] | 842 | * with correct one. It is exactly, which we pretend to do. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 843 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 844 | |
Ilpo Järvinen | ee6aac5 | 2008-12-05 22:43:08 -0800 | [diff] [blame] | 845 | /* NOTE: clamping at TCP_RTO_MIN is not required, current algo |
| 846 | * guarantees that rto is higher. |
| 847 | */ |
Damian Lukowski | f1ecd5d | 2009-08-26 00:16:31 +0000 | [diff] [blame] | 848 | tcp_bound_rto(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 849 | } |
| 850 | |
Eric Dumazet | cf533ea | 2011-10-21 05:22:42 -0400 | [diff] [blame] | 851 | __u32 tcp_init_cwnd(const struct tcp_sock *tp, const struct dst_entry *dst) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 852 | { |
| 853 | __u32 cwnd = (dst ? dst_metric(dst, RTAX_INITCWND) : 0); |
| 854 | |
Gerrit Renker | 22b71c8 | 2010-08-29 19:23:12 +0000 | [diff] [blame] | 855 | if (!cwnd) |
David S. Miller | 442b963 | 2011-02-02 17:05:11 -0800 | [diff] [blame] | 856 | cwnd = TCP_INIT_CWND; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 857 | return min_t(__u32, cwnd, tp->snd_cwnd_clamp); |
| 858 | } |
| 859 | |
Ryousei Takano | 564262c | 2007-10-25 23:03:52 -0700 | [diff] [blame] | 860 | /* Take a notice that peer is sending D-SACKs */ |
Ilpo Järvinen | e60402d | 2007-08-09 15:14:46 +0300 | [diff] [blame] | 861 | static void tcp_dsack_seen(struct tcp_sock *tp) |
| 862 | { |
Vijay Subramanian | ab56222 | 2011-12-20 13:23:24 +0000 | [diff] [blame] | 863 | tp->rx_opt.sack_ok |= TCP_DSACK_SEEN; |
Priyaranjan Jha | 1f25569 | 2017-11-03 16:38:48 -0700 | [diff] [blame] | 864 | tp->rack.dsack_seen = 1; |
Wei Wang | 7e10b65 | 2018-07-31 17:46:23 -0700 | [diff] [blame] | 865 | tp->dsack_dups++; |
Ilpo Järvinen | e60402d | 2007-08-09 15:14:46 +0300 | [diff] [blame] | 866 | } |
| 867 | |
Yuchung Cheng | 737ff31 | 2017-11-08 13:01:27 -0800 | [diff] [blame] | 868 | /* It's reordering when higher sequence was delivered (i.e. sacked) before |
| 869 | * some lower never-retransmitted sequence ("low_seq"). The maximum reordering |
| 870 | * distance is approximated in full-mss packet distance ("reordering"). |
| 871 | */ |
| 872 | static void tcp_check_sack_reordering(struct sock *sk, const u32 low_seq, |
| 873 | const int ts) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 874 | { |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 875 | struct tcp_sock *tp = tcp_sk(sk); |
Yuchung Cheng | 737ff31 | 2017-11-08 13:01:27 -0800 | [diff] [blame] | 876 | const u32 mss = tp->mss_cache; |
| 877 | u32 fack, metric; |
Pavel Emelyanov | 40b215e | 2008-07-03 01:05:41 -0700 | [diff] [blame] | 878 | |
Yuchung Cheng | 737ff31 | 2017-11-08 13:01:27 -0800 | [diff] [blame] | 879 | fack = tcp_highest_sack_seq(tp); |
| 880 | if (!before(low_seq, fack)) |
Soheil Hassas Yeganeh | 6f5b24e | 2017-05-16 17:39:02 -0400 | [diff] [blame] | 881 | return; |
| 882 | |
Yuchung Cheng | 737ff31 | 2017-11-08 13:01:27 -0800 | [diff] [blame] | 883 | metric = fack - low_seq; |
| 884 | if ((metric > tp->reordering * mss) && mss) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 885 | #if FASTRETRANS_DEBUG > 1 |
Joe Perches | 91df42b | 2012-05-15 14:11:54 +0000 | [diff] [blame] | 886 | pr_debug("Disorder%d %d %u f%u s%u rr%d\n", |
| 887 | tp->rx_opt.sack_ok, inet_csk(sk)->icsk_ca_state, |
| 888 | tp->reordering, |
Yuchung Cheng | 737ff31 | 2017-11-08 13:01:27 -0800 | [diff] [blame] | 889 | 0, |
Joe Perches | 91df42b | 2012-05-15 14:11:54 +0000 | [diff] [blame] | 890 | tp->sacked_out, |
| 891 | tp->undo_marker ? tp->undo_retrans : 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 892 | #endif |
Yuchung Cheng | 737ff31 | 2017-11-08 13:01:27 -0800 | [diff] [blame] | 893 | tp->reordering = min_t(u32, (metric + mss - 1) / mss, |
| 894 | sock_net(sk)->ipv4.sysctl_tcp_max_reordering); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 895 | } |
Yuchung Cheng | eed530b | 2012-05-02 13:30:03 +0000 | [diff] [blame] | 896 | |
Yuchung Cheng | 2d2517e | 2017-04-04 14:15:40 -0700 | [diff] [blame] | 897 | /* This exciting event is worth to be remembered. 8) */ |
Wei Wang | 7ec6537 | 2018-07-31 17:46:24 -0700 | [diff] [blame] | 898 | tp->reord_seen++; |
Yuchung Cheng | 737ff31 | 2017-11-08 13:01:27 -0800 | [diff] [blame] | 899 | NET_INC_STATS(sock_net(sk), |
| 900 | ts ? LINUX_MIB_TCPTSREORDER : LINUX_MIB_TCPSACKREORDER); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 901 | } |
| 902 | |
Ilpo Järvinen | 006f582 | 2008-09-20 21:20:20 -0700 | [diff] [blame] | 903 | /* This must be called before lost_out is incremented */ |
Ilpo Järvinen | c8c213f | 2008-09-20 21:18:55 -0700 | [diff] [blame] | 904 | static void tcp_verify_retransmit_hint(struct tcp_sock *tp, struct sk_buff *skb) |
| 905 | { |
Ian Morris | 51456b2 | 2015-04-03 09:17:26 +0100 | [diff] [blame] | 906 | if (!tp->retransmit_skb_hint || |
Ilpo Järvinen | c8c213f | 2008-09-20 21:18:55 -0700 | [diff] [blame] | 907 | before(TCP_SKB_CB(skb)->seq, |
| 908 | TCP_SKB_CB(tp->retransmit_skb_hint)->seq)) |
Ilpo Järvinen | 006f582 | 2008-09-20 21:20:20 -0700 | [diff] [blame] | 909 | tp->retransmit_skb_hint = skb; |
Ilpo Järvinen | c8c213f | 2008-09-20 21:18:55 -0700 | [diff] [blame] | 910 | } |
| 911 | |
Neal Cardwell | 0682e69 | 2016-09-19 23:39:13 -0400 | [diff] [blame] | 912 | /* Sum the number of packets on the wire we have marked as lost. |
| 913 | * There are two cases we care about here: |
| 914 | * a) Packet hasn't been marked lost (nor retransmitted), |
| 915 | * and this is the first loss. |
| 916 | * b) Packet has been marked both lost and retransmitted, |
| 917 | * and this means we think it was lost again. |
| 918 | */ |
| 919 | static void tcp_sum_lost(struct tcp_sock *tp, struct sk_buff *skb) |
| 920 | { |
| 921 | __u8 sacked = TCP_SKB_CB(skb)->sacked; |
| 922 | |
| 923 | if (!(sacked & TCPCB_LOST) || |
| 924 | ((sacked & TCPCB_LOST) && (sacked & TCPCB_SACKED_RETRANS))) |
| 925 | tp->lost += tcp_skb_pcount(skb); |
| 926 | } |
| 927 | |
Ilpo Järvinen | 41ea36e | 2008-09-20 21:19:22 -0700 | [diff] [blame] | 928 | static void tcp_skb_mark_lost(struct tcp_sock *tp, struct sk_buff *skb) |
| 929 | { |
| 930 | if (!(TCP_SKB_CB(skb)->sacked & (TCPCB_LOST|TCPCB_SACKED_ACKED))) { |
| 931 | tcp_verify_retransmit_hint(tp, skb); |
| 932 | |
| 933 | tp->lost_out += tcp_skb_pcount(skb); |
Neal Cardwell | 0682e69 | 2016-09-19 23:39:13 -0400 | [diff] [blame] | 934 | tcp_sum_lost(tp, skb); |
Ilpo Järvinen | 41ea36e | 2008-09-20 21:19:22 -0700 | [diff] [blame] | 935 | TCP_SKB_CB(skb)->sacked |= TCPCB_LOST; |
| 936 | } |
| 937 | } |
| 938 | |
Yuchung Cheng | 4f41b1c | 2015-10-16 21:57:47 -0700 | [diff] [blame] | 939 | void tcp_skb_mark_lost_uncond_verify(struct tcp_sock *tp, struct sk_buff *skb) |
Ilpo Järvinen | 006f582 | 2008-09-20 21:20:20 -0700 | [diff] [blame] | 940 | { |
| 941 | tcp_verify_retransmit_hint(tp, skb); |
| 942 | |
Neal Cardwell | 0682e69 | 2016-09-19 23:39:13 -0400 | [diff] [blame] | 943 | tcp_sum_lost(tp, skb); |
Ilpo Järvinen | 006f582 | 2008-09-20 21:20:20 -0700 | [diff] [blame] | 944 | if (!(TCP_SKB_CB(skb)->sacked & (TCPCB_LOST|TCPCB_SACKED_ACKED))) { |
| 945 | tp->lost_out += tcp_skb_pcount(skb); |
| 946 | TCP_SKB_CB(skb)->sacked |= TCPCB_LOST; |
| 947 | } |
| 948 | } |
| 949 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 950 | /* This procedure tags the retransmission queue when SACKs arrive. |
| 951 | * |
| 952 | * We have three tag bits: SACKED(S), RETRANS(R) and LOST(L). |
| 953 | * Packets in queue with these bits set are counted in variables |
| 954 | * sacked_out, retrans_out and lost_out, correspondingly. |
| 955 | * |
| 956 | * Valid combinations are: |
| 957 | * Tag InFlight Description |
| 958 | * 0 1 - orig segment is in flight. |
| 959 | * S 0 - nothing flies, orig reached receiver. |
| 960 | * L 0 - nothing flies, orig lost by net. |
| 961 | * R 2 - both orig and retransmit are in flight. |
| 962 | * L|R 1 - orig is lost, retransmit is in flight. |
| 963 | * S|R 1 - orig reached receiver, retrans is still in flight. |
| 964 | * (L|S|R is logically valid, it could occur when L|R is sacked, |
| 965 | * but it is equivalent to plain S and code short-curcuits it to S. |
| 966 | * L|S is logically invalid, it would mean -1 packet in flight 8)) |
| 967 | * |
| 968 | * These 6 states form finite state machine, controlled by the following events: |
| 969 | * 1. New ACK (+SACK) arrives. (tcp_sacktag_write_queue()) |
| 970 | * 2. Retransmission. (tcp_retransmit_skb(), tcp_xmit_retransmit_queue()) |
Yuchung Cheng | 974c123 | 2012-01-19 14:42:21 +0000 | [diff] [blame] | 971 | * 3. Loss detection event of two flavors: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 972 | * A. Scoreboard estimator decided the packet is lost. |
| 973 | * A'. Reno "three dupacks" marks head of queue lost. |
Yuchung Cheng | 974c123 | 2012-01-19 14:42:21 +0000 | [diff] [blame] | 974 | * B. SACK arrives sacking SND.NXT at the moment, when the |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 975 | * segment was retransmitted. |
| 976 | * 4. D-SACK added new rule: D-SACK changes any tag to S. |
| 977 | * |
| 978 | * It is pleasant to note, that state diagram turns out to be commutative, |
| 979 | * so that we are allowed not to be bothered by order of our actions, |
| 980 | * when multiple events arrive simultaneously. (see the function below). |
| 981 | * |
| 982 | * Reordering detection. |
| 983 | * -------------------- |
| 984 | * Reordering metric is maximal distance, which a packet can be displaced |
| 985 | * in packet stream. With SACKs we can estimate it: |
| 986 | * |
| 987 | * 1. SACK fills old hole and the corresponding segment was not |
| 988 | * ever retransmitted -> reordering. Alas, we cannot use it |
| 989 | * when segment was retransmitted. |
| 990 | * 2. The last flaw is solved with D-SACK. D-SACK arrives |
| 991 | * for retransmitted and already SACKed segment -> reordering.. |
| 992 | * Both of these heuristics are not used in Loss state, when we cannot |
| 993 | * account for retransmits accurately. |
Ilpo Järvinen | 5b3c988 | 2007-08-24 22:54:44 -0700 | [diff] [blame] | 994 | * |
| 995 | * SACK block validation. |
| 996 | * ---------------------- |
| 997 | * |
| 998 | * SACK block range validation checks that the received SACK block fits to |
| 999 | * the expected sequence limits, i.e., it is between SND.UNA and SND.NXT. |
| 1000 | * Note that SND.UNA is not included to the range though being valid because |
Ilpo Järvinen | 0e83533 | 2007-10-01 15:28:17 -0700 | [diff] [blame] | 1001 | * it means that the receiver is rather inconsistent with itself reporting |
| 1002 | * SACK reneging when it should advance SND.UNA. Such SACK block this is |
| 1003 | * perfectly valid, however, in light of RFC2018 which explicitly states |
| 1004 | * that "SACK block MUST reflect the newest segment. Even if the newest |
| 1005 | * segment is going to be discarded ...", not that it looks very clever |
| 1006 | * in case of head skb. Due to potentional receiver driven attacks, we |
| 1007 | * choose to avoid immediate execution of a walk in write queue due to |
| 1008 | * reneging and defer head skb's loss recovery to standard loss recovery |
| 1009 | * procedure that will eventually trigger (nothing forbids us doing this). |
Ilpo Järvinen | 5b3c988 | 2007-08-24 22:54:44 -0700 | [diff] [blame] | 1010 | * |
| 1011 | * Implements also blockage to start_seq wrap-around. Problem lies in the |
| 1012 | * fact that though start_seq (s) is before end_seq (i.e., not reversed), |
| 1013 | * there's no guarantee that it will be before snd_nxt (n). The problem |
| 1014 | * happens when start_seq resides between end_seq wrap (e_w) and snd_nxt |
| 1015 | * wrap (s_w): |
| 1016 | * |
| 1017 | * <- outs wnd -> <- wrapzone -> |
| 1018 | * u e n u_w e_w s n_w |
| 1019 | * | | | | | | | |
| 1020 | * |<------------+------+----- TCP seqno space --------------+---------->| |
| 1021 | * ...-- <2^31 ->| |<--------... |
| 1022 | * ...---- >2^31 ------>| |<--------... |
| 1023 | * |
| 1024 | * Current code wouldn't be vulnerable but it's better still to discard such |
| 1025 | * crazy SACK blocks. Doing this check for start_seq alone closes somewhat |
| 1026 | * similar case (end_seq after snd_nxt wrap) as earlier reversed check in |
| 1027 | * snd_nxt wrap -> snd_una region will then become "well defined", i.e., |
| 1028 | * equal to the ideal case (infinite seqno space without wrap caused issues). |
| 1029 | * |
| 1030 | * With D-SACK the lower bound is extended to cover sequence space below |
| 1031 | * SND.UNA down to undo_marker, which is the last point of interest. Yet |
Ryousei Takano | 564262c | 2007-10-25 23:03:52 -0700 | [diff] [blame] | 1032 | * again, D-SACK block must not to go across snd_una (for the same reason as |
Ilpo Järvinen | 5b3c988 | 2007-08-24 22:54:44 -0700 | [diff] [blame] | 1033 | * for the normal SACK blocks, explained above). But there all simplicity |
| 1034 | * ends, TCP might receive valid D-SACKs below that. As long as they reside |
| 1035 | * fully below undo_marker they do not affect behavior in anyway and can |
| 1036 | * therefore be safely ignored. In rare cases (which are more or less |
| 1037 | * theoretical ones), the D-SACK will nicely cross that boundary due to skb |
| 1038 | * fragmentation and packet reordering past skb's retransmission. To consider |
| 1039 | * them correctly, the acceptable range must be extended even more though |
| 1040 | * the exact amount is rather hard to quantify. However, tp->max_window can |
| 1041 | * be used as an exaggerated estimate. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1042 | */ |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 1043 | static bool tcp_is_sackblock_valid(struct tcp_sock *tp, bool is_dsack, |
| 1044 | u32 start_seq, u32 end_seq) |
Ilpo Järvinen | 5b3c988 | 2007-08-24 22:54:44 -0700 | [diff] [blame] | 1045 | { |
| 1046 | /* Too far in future, or reversed (interpretation is ambiguous) */ |
| 1047 | if (after(end_seq, tp->snd_nxt) || !before(start_seq, end_seq)) |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 1048 | return false; |
Ilpo Järvinen | 5b3c988 | 2007-08-24 22:54:44 -0700 | [diff] [blame] | 1049 | |
| 1050 | /* Nasty start_seq wrap-around check (see comments above) */ |
| 1051 | if (!before(start_seq, tp->snd_nxt)) |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 1052 | return false; |
Ilpo Järvinen | 5b3c988 | 2007-08-24 22:54:44 -0700 | [diff] [blame] | 1053 | |
Ryousei Takano | 564262c | 2007-10-25 23:03:52 -0700 | [diff] [blame] | 1054 | /* In outstanding window? ...This is valid exit for D-SACKs too. |
Ilpo Järvinen | 5b3c988 | 2007-08-24 22:54:44 -0700 | [diff] [blame] | 1055 | * start_seq == snd_una is non-sensical (see comments above) |
| 1056 | */ |
| 1057 | if (after(start_seq, tp->snd_una)) |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 1058 | return true; |
Ilpo Järvinen | 5b3c988 | 2007-08-24 22:54:44 -0700 | [diff] [blame] | 1059 | |
| 1060 | if (!is_dsack || !tp->undo_marker) |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 1061 | return false; |
Ilpo Järvinen | 5b3c988 | 2007-08-24 22:54:44 -0700 | [diff] [blame] | 1062 | |
| 1063 | /* ...Then it's D-SACK, and must reside below snd_una completely */ |
Zheng Yan | f779b2d | 2011-09-18 22:37:34 -0400 | [diff] [blame] | 1064 | if (after(end_seq, tp->snd_una)) |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 1065 | return false; |
Ilpo Järvinen | 5b3c988 | 2007-08-24 22:54:44 -0700 | [diff] [blame] | 1066 | |
| 1067 | if (!before(start_seq, tp->undo_marker)) |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 1068 | return true; |
Ilpo Järvinen | 5b3c988 | 2007-08-24 22:54:44 -0700 | [diff] [blame] | 1069 | |
| 1070 | /* Too old */ |
| 1071 | if (!after(end_seq, tp->undo_marker)) |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 1072 | return false; |
Ilpo Järvinen | 5b3c988 | 2007-08-24 22:54:44 -0700 | [diff] [blame] | 1073 | |
| 1074 | /* Undo_marker boundary crossing (overestimates a lot). Known already: |
| 1075 | * start_seq < undo_marker and end_seq >= undo_marker. |
| 1076 | */ |
| 1077 | return !before(start_seq, end_seq - tp->max_window); |
| 1078 | } |
| 1079 | |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 1080 | static bool tcp_check_dsack(struct sock *sk, const struct sk_buff *ack_skb, |
| 1081 | struct tcp_sack_block_wire *sp, int num_sacks, |
| 1082 | u32 prior_snd_una) |
David S. Miller | d06e021 | 2007-06-18 22:43:06 -0700 | [diff] [blame] | 1083 | { |
Pavel Emelyanov | 1ed8346 | 2008-07-16 20:29:51 -0700 | [diff] [blame] | 1084 | struct tcp_sock *tp = tcp_sk(sk); |
Harvey Harrison | d3e2ce3 | 2008-05-02 16:26:16 -0700 | [diff] [blame] | 1085 | u32 start_seq_0 = get_unaligned_be32(&sp[0].start_seq); |
| 1086 | u32 end_seq_0 = get_unaligned_be32(&sp[0].end_seq); |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 1087 | bool dup_sack = false; |
David S. Miller | d06e021 | 2007-06-18 22:43:06 -0700 | [diff] [blame] | 1088 | |
| 1089 | if (before(start_seq_0, TCP_SKB_CB(ack_skb)->ack_seq)) { |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 1090 | dup_sack = true; |
Ilpo Järvinen | e60402d | 2007-08-09 15:14:46 +0300 | [diff] [blame] | 1091 | tcp_dsack_seen(tp); |
Eric Dumazet | c10d931 | 2016-04-29 14:16:47 -0700 | [diff] [blame] | 1092 | NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPDSACKRECV); |
David S. Miller | d06e021 | 2007-06-18 22:43:06 -0700 | [diff] [blame] | 1093 | } else if (num_sacks > 1) { |
Harvey Harrison | d3e2ce3 | 2008-05-02 16:26:16 -0700 | [diff] [blame] | 1094 | u32 end_seq_1 = get_unaligned_be32(&sp[1].end_seq); |
| 1095 | u32 start_seq_1 = get_unaligned_be32(&sp[1].start_seq); |
David S. Miller | d06e021 | 2007-06-18 22:43:06 -0700 | [diff] [blame] | 1096 | |
| 1097 | if (!after(end_seq_0, end_seq_1) && |
| 1098 | !before(start_seq_0, start_seq_1)) { |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 1099 | dup_sack = true; |
Ilpo Järvinen | e60402d | 2007-08-09 15:14:46 +0300 | [diff] [blame] | 1100 | tcp_dsack_seen(tp); |
Eric Dumazet | c10d931 | 2016-04-29 14:16:47 -0700 | [diff] [blame] | 1101 | NET_INC_STATS(sock_net(sk), |
Pavel Emelyanov | de0744a | 2008-07-16 20:31:16 -0700 | [diff] [blame] | 1102 | LINUX_MIB_TCPDSACKOFORECV); |
David S. Miller | d06e021 | 2007-06-18 22:43:06 -0700 | [diff] [blame] | 1103 | } |
| 1104 | } |
| 1105 | |
| 1106 | /* D-SACK for already forgotten data... Do dumb counting. */ |
Yuchung Cheng | 6e08d5e | 2014-07-02 12:07:16 -0700 | [diff] [blame] | 1107 | if (dup_sack && tp->undo_marker && tp->undo_retrans > 0 && |
David S. Miller | d06e021 | 2007-06-18 22:43:06 -0700 | [diff] [blame] | 1108 | !after(end_seq_0, prior_snd_una) && |
| 1109 | after(end_seq_0, tp->undo_marker)) |
| 1110 | tp->undo_retrans--; |
| 1111 | |
| 1112 | return dup_sack; |
| 1113 | } |
| 1114 | |
Ilpo Järvinen | a1197f5 | 2008-12-05 22:42:22 -0800 | [diff] [blame] | 1115 | struct tcp_sacktag_state { |
Yuchung Cheng | 737ff31 | 2017-11-08 13:01:27 -0800 | [diff] [blame] | 1116 | u32 reord; |
Kenneth Klette Jonassen | 31231a8 | 2015-05-01 01:10:58 +0200 | [diff] [blame] | 1117 | /* Timestamps for earliest and latest never-retransmitted segment |
| 1118 | * that was SACKed. RTO needs the earliest RTT to stay conservative, |
| 1119 | * but congestion control should still get an accurate delay signal. |
| 1120 | */ |
Eric Dumazet | 9a568de | 2017-05-16 14:00:14 -0700 | [diff] [blame] | 1121 | u64 first_sackt; |
| 1122 | u64 last_sackt; |
Yuchung Cheng | b9f6482 | 2016-09-19 23:39:14 -0400 | [diff] [blame] | 1123 | struct rate_sample *rate; |
Eric Dumazet | 740b0f1 | 2014-02-26 14:02:48 -0800 | [diff] [blame] | 1124 | int flag; |
Eric Dumazet | 75c119a | 2017-10-05 22:21:27 -0700 | [diff] [blame] | 1125 | unsigned int mss_now; |
Ilpo Järvinen | a1197f5 | 2008-12-05 22:42:22 -0800 | [diff] [blame] | 1126 | }; |
| 1127 | |
Ilpo Järvinen | d193594 | 2007-10-11 17:34:25 -0700 | [diff] [blame] | 1128 | /* Check if skb is fully within the SACK block. In presence of GSO skbs, |
| 1129 | * the incoming SACK may not exactly match but we can find smaller MSS |
| 1130 | * aligned portion of it that matches. Therefore we might need to fragment |
| 1131 | * which may fail and creates some hassle (caller must handle error case |
| 1132 | * returns). |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1133 | * |
| 1134 | * FIXME: this could be merged to shift decision code |
Ilpo Järvinen | d193594 | 2007-10-11 17:34:25 -0700 | [diff] [blame] | 1135 | */ |
Adrian Bunk | 0f79efd | 2007-10-26 03:57:36 -0700 | [diff] [blame] | 1136 | static int tcp_match_skb_to_sack(struct sock *sk, struct sk_buff *skb, |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 1137 | u32 start_seq, u32 end_seq) |
Ilpo Järvinen | d193594 | 2007-10-11 17:34:25 -0700 | [diff] [blame] | 1138 | { |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 1139 | int err; |
| 1140 | bool in_sack; |
Ilpo Järvinen | d193594 | 2007-10-11 17:34:25 -0700 | [diff] [blame] | 1141 | unsigned int pkt_len; |
Ilpo Järvinen | adb92db | 2008-11-24 21:13:50 -0800 | [diff] [blame] | 1142 | unsigned int mss; |
Ilpo Järvinen | d193594 | 2007-10-11 17:34:25 -0700 | [diff] [blame] | 1143 | |
| 1144 | in_sack = !after(start_seq, TCP_SKB_CB(skb)->seq) && |
| 1145 | !before(end_seq, TCP_SKB_CB(skb)->end_seq); |
| 1146 | |
| 1147 | if (tcp_skb_pcount(skb) > 1 && !in_sack && |
| 1148 | after(TCP_SKB_CB(skb)->end_seq, start_seq)) { |
Ilpo Järvinen | adb92db | 2008-11-24 21:13:50 -0800 | [diff] [blame] | 1149 | mss = tcp_skb_mss(skb); |
Ilpo Järvinen | d193594 | 2007-10-11 17:34:25 -0700 | [diff] [blame] | 1150 | in_sack = !after(start_seq, TCP_SKB_CB(skb)->seq); |
| 1151 | |
Ilpo Järvinen | adb92db | 2008-11-24 21:13:50 -0800 | [diff] [blame] | 1152 | if (!in_sack) { |
Ilpo Järvinen | d193594 | 2007-10-11 17:34:25 -0700 | [diff] [blame] | 1153 | pkt_len = start_seq - TCP_SKB_CB(skb)->seq; |
Ilpo Järvinen | adb92db | 2008-11-24 21:13:50 -0800 | [diff] [blame] | 1154 | if (pkt_len < mss) |
| 1155 | pkt_len = mss; |
| 1156 | } else { |
Ilpo Järvinen | d193594 | 2007-10-11 17:34:25 -0700 | [diff] [blame] | 1157 | pkt_len = end_seq - TCP_SKB_CB(skb)->seq; |
Ilpo Järvinen | adb92db | 2008-11-24 21:13:50 -0800 | [diff] [blame] | 1158 | if (pkt_len < mss) |
| 1159 | return -EINVAL; |
| 1160 | } |
| 1161 | |
| 1162 | /* Round if necessary so that SACKs cover only full MSSes |
| 1163 | * and/or the remaining small portion (if present) |
| 1164 | */ |
| 1165 | if (pkt_len > mss) { |
| 1166 | unsigned int new_len = (pkt_len / mss) * mss; |
Yuchung Cheng | b451e5d | 2017-05-10 17:01:27 -0700 | [diff] [blame] | 1167 | if (!in_sack && new_len < pkt_len) |
Ilpo Järvinen | adb92db | 2008-11-24 21:13:50 -0800 | [diff] [blame] | 1168 | new_len += mss; |
Ilpo Järvinen | adb92db | 2008-11-24 21:13:50 -0800 | [diff] [blame] | 1169 | pkt_len = new_len; |
| 1170 | } |
Yuchung Cheng | b451e5d | 2017-05-10 17:01:27 -0700 | [diff] [blame] | 1171 | |
| 1172 | if (pkt_len >= skb->len && !in_sack) |
| 1173 | return 0; |
| 1174 | |
Eric Dumazet | 75c119a | 2017-10-05 22:21:27 -0700 | [diff] [blame] | 1175 | err = tcp_fragment(sk, TCP_FRAG_IN_RTX_QUEUE, skb, |
| 1176 | pkt_len, mss, GFP_ATOMIC); |
Ilpo Järvinen | d193594 | 2007-10-11 17:34:25 -0700 | [diff] [blame] | 1177 | if (err < 0) |
| 1178 | return err; |
| 1179 | } |
| 1180 | |
| 1181 | return in_sack; |
| 1182 | } |
| 1183 | |
Neal Cardwell | cc9a672 | 2012-02-12 18:37:09 +0000 | [diff] [blame] | 1184 | /* Mark the given newly-SACKed range as such, adjusting counters and hints. */ |
| 1185 | static u8 tcp_sacktag_one(struct sock *sk, |
| 1186 | struct tcp_sacktag_state *state, u8 sacked, |
| 1187 | u32 start_seq, u32 end_seq, |
Eric Dumazet | 740b0f1 | 2014-02-26 14:02:48 -0800 | [diff] [blame] | 1188 | int dup_sack, int pcount, |
Eric Dumazet | 9a568de | 2017-05-16 14:00:14 -0700 | [diff] [blame] | 1189 | u64 xmit_time) |
Ilpo Järvinen | 9e10c47c | 2007-11-15 19:44:56 -0800 | [diff] [blame] | 1190 | { |
Ilpo Järvinen | 6859d49 | 2007-12-02 00:48:06 +0200 | [diff] [blame] | 1191 | struct tcp_sock *tp = tcp_sk(sk); |
Ilpo Järvinen | 9e10c47c | 2007-11-15 19:44:56 -0800 | [diff] [blame] | 1192 | |
| 1193 | /* Account D-SACK for retransmitted packet. */ |
| 1194 | if (dup_sack && (sacked & TCPCB_RETRANS)) { |
Yuchung Cheng | 6e08d5e | 2014-07-02 12:07:16 -0700 | [diff] [blame] | 1195 | if (tp->undo_marker && tp->undo_retrans > 0 && |
Neal Cardwell | cc9a672 | 2012-02-12 18:37:09 +0000 | [diff] [blame] | 1196 | after(end_seq, tp->undo_marker)) |
Ilpo Järvinen | 9e10c47c | 2007-11-15 19:44:56 -0800 | [diff] [blame] | 1197 | tp->undo_retrans--; |
Yuchung Cheng | 737ff31 | 2017-11-08 13:01:27 -0800 | [diff] [blame] | 1198 | if ((sacked & TCPCB_SACKED_ACKED) && |
| 1199 | before(start_seq, state->reord)) |
| 1200 | state->reord = start_seq; |
Ilpo Järvinen | 9e10c47c | 2007-11-15 19:44:56 -0800 | [diff] [blame] | 1201 | } |
| 1202 | |
| 1203 | /* Nothing to do; acked frame is about to be dropped (was ACKed). */ |
Neal Cardwell | cc9a672 | 2012-02-12 18:37:09 +0000 | [diff] [blame] | 1204 | if (!after(end_seq, tp->snd_una)) |
Ilpo Järvinen | a1197f5 | 2008-12-05 22:42:22 -0800 | [diff] [blame] | 1205 | return sacked; |
Ilpo Järvinen | 9e10c47c | 2007-11-15 19:44:56 -0800 | [diff] [blame] | 1206 | |
| 1207 | if (!(sacked & TCPCB_SACKED_ACKED)) { |
Eric Dumazet | d2329f1 | 2017-04-25 10:15:38 -0700 | [diff] [blame] | 1208 | tcp_rack_advance(tp, sacked, end_seq, xmit_time); |
Yuchung Cheng | 659a8ad | 2015-10-16 21:57:46 -0700 | [diff] [blame] | 1209 | |
Ilpo Järvinen | 9e10c47c | 2007-11-15 19:44:56 -0800 | [diff] [blame] | 1210 | if (sacked & TCPCB_SACKED_RETRANS) { |
| 1211 | /* If the segment is not tagged as lost, |
| 1212 | * we do not clear RETRANS, believing |
| 1213 | * that retransmission is still in flight. |
| 1214 | */ |
| 1215 | if (sacked & TCPCB_LOST) { |
Ilpo Järvinen | a1197f5 | 2008-12-05 22:42:22 -0800 | [diff] [blame] | 1216 | sacked &= ~(TCPCB_LOST|TCPCB_SACKED_RETRANS); |
Ilpo Järvinen | f58b22f | 2008-11-24 21:14:43 -0800 | [diff] [blame] | 1217 | tp->lost_out -= pcount; |
| 1218 | tp->retrans_out -= pcount; |
Ilpo Järvinen | 9e10c47c | 2007-11-15 19:44:56 -0800 | [diff] [blame] | 1219 | } |
| 1220 | } else { |
| 1221 | if (!(sacked & TCPCB_RETRANS)) { |
| 1222 | /* New sack for not retransmitted frame, |
| 1223 | * which was in hole. It is reordering. |
| 1224 | */ |
Neal Cardwell | cc9a672 | 2012-02-12 18:37:09 +0000 | [diff] [blame] | 1225 | if (before(start_seq, |
Yuchung Cheng | 737ff31 | 2017-11-08 13:01:27 -0800 | [diff] [blame] | 1226 | tcp_highest_sack_seq(tp)) && |
| 1227 | before(start_seq, state->reord)) |
| 1228 | state->reord = start_seq; |
| 1229 | |
Yuchung Cheng | e33099f | 2013-03-20 13:33:00 +0000 | [diff] [blame] | 1230 | if (!after(end_seq, tp->high_seq)) |
| 1231 | state->flag |= FLAG_ORIG_SACK_ACKED; |
Eric Dumazet | 9a568de | 2017-05-16 14:00:14 -0700 | [diff] [blame] | 1232 | if (state->first_sackt == 0) |
| 1233 | state->first_sackt = xmit_time; |
| 1234 | state->last_sackt = xmit_time; |
Ilpo Järvinen | 9e10c47c | 2007-11-15 19:44:56 -0800 | [diff] [blame] | 1235 | } |
| 1236 | |
| 1237 | if (sacked & TCPCB_LOST) { |
Ilpo Järvinen | a1197f5 | 2008-12-05 22:42:22 -0800 | [diff] [blame] | 1238 | sacked &= ~TCPCB_LOST; |
Ilpo Järvinen | f58b22f | 2008-11-24 21:14:43 -0800 | [diff] [blame] | 1239 | tp->lost_out -= pcount; |
Ilpo Järvinen | 9e10c47c | 2007-11-15 19:44:56 -0800 | [diff] [blame] | 1240 | } |
| 1241 | } |
| 1242 | |
Ilpo Järvinen | a1197f5 | 2008-12-05 22:42:22 -0800 | [diff] [blame] | 1243 | sacked |= TCPCB_SACKED_ACKED; |
| 1244 | state->flag |= FLAG_DATA_SACKED; |
Ilpo Järvinen | f58b22f | 2008-11-24 21:14:43 -0800 | [diff] [blame] | 1245 | tp->sacked_out += pcount; |
Yuchung Cheng | ddf1af6 | 2016-02-02 10:33:06 -0800 | [diff] [blame] | 1246 | tp->delivered += pcount; /* Out-of-order packets delivered */ |
Ilpo Järvinen | 9e10c47c | 2007-11-15 19:44:56 -0800 | [diff] [blame] | 1247 | |
Ilpo Järvinen | 9e10c47c | 2007-11-15 19:44:56 -0800 | [diff] [blame] | 1248 | /* Lost marker hint past SACKed? Tweak RFC3517 cnt */ |
Yuchung Cheng | 713bafe | 2017-11-08 13:01:26 -0800 | [diff] [blame] | 1249 | if (tp->lost_skb_hint && |
Neal Cardwell | cc9a672 | 2012-02-12 18:37:09 +0000 | [diff] [blame] | 1250 | before(start_seq, TCP_SKB_CB(tp->lost_skb_hint)->seq)) |
Ilpo Järvinen | f58b22f | 2008-11-24 21:14:43 -0800 | [diff] [blame] | 1251 | tp->lost_cnt_hint += pcount; |
Ilpo Järvinen | 9e10c47c | 2007-11-15 19:44:56 -0800 | [diff] [blame] | 1252 | } |
| 1253 | |
| 1254 | /* D-SACK. We can detect redundant retransmission in S|R and plain R |
| 1255 | * frames and clear it. undo_retrans is decreased above, L|R frames |
| 1256 | * are accounted above as well. |
| 1257 | */ |
Ilpo Järvinen | a1197f5 | 2008-12-05 22:42:22 -0800 | [diff] [blame] | 1258 | if (dup_sack && (sacked & TCPCB_SACKED_RETRANS)) { |
| 1259 | sacked &= ~TCPCB_SACKED_RETRANS; |
Ilpo Järvinen | f58b22f | 2008-11-24 21:14:43 -0800 | [diff] [blame] | 1260 | tp->retrans_out -= pcount; |
Ilpo Järvinen | 9e10c47c | 2007-11-15 19:44:56 -0800 | [diff] [blame] | 1261 | } |
| 1262 | |
Ilpo Järvinen | a1197f5 | 2008-12-05 22:42:22 -0800 | [diff] [blame] | 1263 | return sacked; |
Ilpo Järvinen | 9e10c47c | 2007-11-15 19:44:56 -0800 | [diff] [blame] | 1264 | } |
| 1265 | |
Neal Cardwell | daef52b | 2012-02-12 18:37:10 +0000 | [diff] [blame] | 1266 | /* Shift newly-SACKed bytes from this skb to the immediately previous |
| 1267 | * already-SACKed sk_buff. Mark the newly-SACKed bytes as such. |
| 1268 | */ |
Eric Dumazet | f331981 | 2017-10-05 22:21:26 -0700 | [diff] [blame] | 1269 | static bool tcp_shifted_skb(struct sock *sk, struct sk_buff *prev, |
| 1270 | struct sk_buff *skb, |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 1271 | struct tcp_sacktag_state *state, |
| 1272 | unsigned int pcount, int shifted, int mss, |
| 1273 | bool dup_sack) |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1274 | { |
| 1275 | struct tcp_sock *tp = tcp_sk(sk); |
Neal Cardwell | daef52b | 2012-02-12 18:37:10 +0000 | [diff] [blame] | 1276 | u32 start_seq = TCP_SKB_CB(skb)->seq; /* start of newly-SACKed */ |
| 1277 | u32 end_seq = start_seq + shifted; /* end of newly-SACKed */ |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1278 | |
| 1279 | BUG_ON(!pcount); |
| 1280 | |
Neal Cardwell | 4c90d3b | 2012-02-26 10:06:19 +0000 | [diff] [blame] | 1281 | /* Adjust counters and hints for the newly sacked sequence |
| 1282 | * range but discard the return value since prev is already |
| 1283 | * marked. We must tag the range first because the seq |
| 1284 | * advancement below implicitly advances |
| 1285 | * tcp_highest_sack_seq() when skb is highest_sack. |
| 1286 | */ |
| 1287 | tcp_sacktag_one(sk, state, TCP_SKB_CB(skb)->sacked, |
Yuchung Cheng | 59c9af4 | 2013-07-22 16:20:47 -0700 | [diff] [blame] | 1288 | start_seq, end_seq, dup_sack, pcount, |
Eric Dumazet | 2fd66ff | 2018-09-21 08:51:47 -0700 | [diff] [blame] | 1289 | tcp_skb_timestamp_us(skb)); |
Yuchung Cheng | b9f6482 | 2016-09-19 23:39:14 -0400 | [diff] [blame] | 1290 | tcp_rate_skb_delivered(sk, skb, state->rate); |
Neal Cardwell | 4c90d3b | 2012-02-26 10:06:19 +0000 | [diff] [blame] | 1291 | |
| 1292 | if (skb == tp->lost_skb_hint) |
Neal Cardwell | 0af2a0d | 2012-02-13 20:22:08 +0000 | [diff] [blame] | 1293 | tp->lost_cnt_hint += pcount; |
| 1294 | |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1295 | TCP_SKB_CB(prev)->end_seq += shifted; |
| 1296 | TCP_SKB_CB(skb)->seq += shifted; |
| 1297 | |
Eric Dumazet | cd7d849 | 2014-09-24 04:11:22 -0700 | [diff] [blame] | 1298 | tcp_skb_pcount_add(prev, pcount); |
| 1299 | BUG_ON(tcp_skb_pcount(skb) < pcount); |
| 1300 | tcp_skb_pcount_add(skb, -pcount); |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1301 | |
| 1302 | /* When we're adding to gso_segs == 1, gso_size will be zero, |
| 1303 | * in theory this shouldn't be necessary but as long as DSACK |
| 1304 | * code can come after this skb later on it's better to keep |
| 1305 | * setting gso_size to something. |
| 1306 | */ |
Eric Dumazet | f69ad29 | 2015-06-11 09:15:18 -0700 | [diff] [blame] | 1307 | if (!TCP_SKB_CB(prev)->tcp_gso_size) |
| 1308 | TCP_SKB_CB(prev)->tcp_gso_size = mss; |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1309 | |
| 1310 | /* CHECKME: To clear or not to clear? Mimics normal skb currently */ |
Eric Dumazet | 51466a7 | 2015-06-11 09:15:16 -0700 | [diff] [blame] | 1311 | if (tcp_skb_pcount(skb) <= 1) |
Eric Dumazet | f69ad29 | 2015-06-11 09:15:18 -0700 | [diff] [blame] | 1312 | TCP_SKB_CB(skb)->tcp_gso_size = 0; |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1313 | |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1314 | /* Difference in this won't matter, both ACKed by the same cumul. ACK */ |
| 1315 | TCP_SKB_CB(prev)->sacked |= (TCP_SKB_CB(skb)->sacked & TCPCB_EVER_RETRANS); |
| 1316 | |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1317 | if (skb->len > 0) { |
| 1318 | BUG_ON(!tcp_skb_pcount(skb)); |
Eric Dumazet | c10d931 | 2016-04-29 14:16:47 -0700 | [diff] [blame] | 1319 | NET_INC_STATS(sock_net(sk), LINUX_MIB_SACKSHIFTED); |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 1320 | return false; |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1321 | } |
| 1322 | |
| 1323 | /* Whole SKB was eaten :-) */ |
| 1324 | |
Ilpo Järvinen | 92ee76b | 2008-11-24 21:26:56 -0800 | [diff] [blame] | 1325 | if (skb == tp->retransmit_skb_hint) |
| 1326 | tp->retransmit_skb_hint = prev; |
Ilpo Järvinen | 92ee76b | 2008-11-24 21:26:56 -0800 | [diff] [blame] | 1327 | if (skb == tp->lost_skb_hint) { |
| 1328 | tp->lost_skb_hint = prev; |
| 1329 | tp->lost_cnt_hint -= tcp_skb_pcount(prev); |
| 1330 | } |
| 1331 | |
Eric Dumazet | 5e8a402f | 2013-10-04 10:31:41 -0700 | [diff] [blame] | 1332 | TCP_SKB_CB(prev)->tcp_flags |= TCP_SKB_CB(skb)->tcp_flags; |
Martin KaFai Lau | a643b5d | 2016-04-25 14:44:49 -0700 | [diff] [blame] | 1333 | TCP_SKB_CB(prev)->eor = TCP_SKB_CB(skb)->eor; |
Eric Dumazet | 5e8a402f | 2013-10-04 10:31:41 -0700 | [diff] [blame] | 1334 | if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) |
| 1335 | TCP_SKB_CB(prev)->end_seq++; |
| 1336 | |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1337 | if (skb == tcp_highest_sack(sk)) |
| 1338 | tcp_advance_highest_sack(sk, skb); |
| 1339 | |
Martin KaFai Lau | cfea5a6 | 2016-04-19 22:39:29 -0700 | [diff] [blame] | 1340 | tcp_skb_collapse_tstamp(prev, skb); |
Eric Dumazet | 9a568de | 2017-05-16 14:00:14 -0700 | [diff] [blame] | 1341 | if (unlikely(TCP_SKB_CB(prev)->tx.delivered_mstamp)) |
| 1342 | TCP_SKB_CB(prev)->tx.delivered_mstamp = 0; |
Yuchung Cheng | b9f6482 | 2016-09-19 23:39:14 -0400 | [diff] [blame] | 1343 | |
Eric Dumazet | 75c119a | 2017-10-05 22:21:27 -0700 | [diff] [blame] | 1344 | tcp_rtx_queue_unlink_and_free(skb, sk); |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1345 | |
Eric Dumazet | c10d931 | 2016-04-29 14:16:47 -0700 | [diff] [blame] | 1346 | NET_INC_STATS(sock_net(sk), LINUX_MIB_SACKMERGED); |
Ilpo Järvinen | 111cc8b | 2008-11-24 21:27:22 -0800 | [diff] [blame] | 1347 | |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 1348 | return true; |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1349 | } |
| 1350 | |
| 1351 | /* I wish gso_size would have a bit more sane initialization than |
| 1352 | * something-or-zero which complicates things |
| 1353 | */ |
Eric Dumazet | cf533ea | 2011-10-21 05:22:42 -0400 | [diff] [blame] | 1354 | static int tcp_skb_seglen(const struct sk_buff *skb) |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1355 | { |
Ilpo Järvinen | 775ffab | 2008-12-05 22:41:26 -0800 | [diff] [blame] | 1356 | return tcp_skb_pcount(skb) == 1 ? skb->len : tcp_skb_mss(skb); |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1357 | } |
| 1358 | |
| 1359 | /* Shifting pages past head area doesn't work */ |
Eric Dumazet | cf533ea | 2011-10-21 05:22:42 -0400 | [diff] [blame] | 1360 | static int skb_can_shift(const struct sk_buff *skb) |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1361 | { |
| 1362 | return !skb_headlen(skb) && skb_is_nonlinear(skb); |
| 1363 | } |
| 1364 | |
| 1365 | /* Try collapsing SACK blocks spanning across multiple skbs to a single |
| 1366 | * skb. |
| 1367 | */ |
| 1368 | static struct sk_buff *tcp_shift_skb_data(struct sock *sk, struct sk_buff *skb, |
Ilpo Järvinen | a1197f5 | 2008-12-05 22:42:22 -0800 | [diff] [blame] | 1369 | struct tcp_sacktag_state *state, |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1370 | u32 start_seq, u32 end_seq, |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 1371 | bool dup_sack) |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1372 | { |
| 1373 | struct tcp_sock *tp = tcp_sk(sk); |
| 1374 | struct sk_buff *prev; |
| 1375 | int mss; |
| 1376 | int pcount = 0; |
| 1377 | int len; |
| 1378 | int in_sack; |
| 1379 | |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1380 | /* Normally R but no L won't result in plain S */ |
| 1381 | if (!dup_sack && |
Ilpo Järvinen | 9969ca5 | 2008-12-05 22:41:06 -0800 | [diff] [blame] | 1382 | (TCP_SKB_CB(skb)->sacked & (TCPCB_LOST|TCPCB_SACKED_RETRANS)) == TCPCB_SACKED_RETRANS) |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1383 | goto fallback; |
| 1384 | if (!skb_can_shift(skb)) |
| 1385 | goto fallback; |
| 1386 | /* This frame is about to be dropped (was ACKed). */ |
| 1387 | if (!after(TCP_SKB_CB(skb)->end_seq, tp->snd_una)) |
| 1388 | goto fallback; |
| 1389 | |
| 1390 | /* Can only happen with delayed DSACK + discard craziness */ |
Eric Dumazet | 75c119a | 2017-10-05 22:21:27 -0700 | [diff] [blame] | 1391 | prev = skb_rb_prev(skb); |
| 1392 | if (!prev) |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1393 | goto fallback; |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1394 | |
| 1395 | if ((TCP_SKB_CB(prev)->sacked & TCPCB_TAGBITS) != TCPCB_SACKED_ACKED) |
| 1396 | goto fallback; |
| 1397 | |
Martin KaFai Lau | a643b5d | 2016-04-25 14:44:49 -0700 | [diff] [blame] | 1398 | if (!tcp_skb_can_collapse_to(prev)) |
| 1399 | goto fallback; |
| 1400 | |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1401 | in_sack = !after(start_seq, TCP_SKB_CB(skb)->seq) && |
| 1402 | !before(end_seq, TCP_SKB_CB(skb)->end_seq); |
| 1403 | |
| 1404 | if (in_sack) { |
| 1405 | len = skb->len; |
| 1406 | pcount = tcp_skb_pcount(skb); |
Ilpo Järvinen | 775ffab | 2008-12-05 22:41:26 -0800 | [diff] [blame] | 1407 | mss = tcp_skb_seglen(skb); |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1408 | |
| 1409 | /* TODO: Fix DSACKs to not fragment already SACKed and we can |
| 1410 | * drop this restriction as unnecessary |
| 1411 | */ |
Ilpo Järvinen | 775ffab | 2008-12-05 22:41:26 -0800 | [diff] [blame] | 1412 | if (mss != tcp_skb_seglen(prev)) |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1413 | goto fallback; |
| 1414 | } else { |
| 1415 | if (!after(TCP_SKB_CB(skb)->end_seq, start_seq)) |
| 1416 | goto noop; |
| 1417 | /* CHECKME: This is non-MSS split case only?, this will |
| 1418 | * cause skipped skbs due to advancing loop btw, original |
| 1419 | * has that feature too |
| 1420 | */ |
| 1421 | if (tcp_skb_pcount(skb) <= 1) |
| 1422 | goto noop; |
| 1423 | |
| 1424 | in_sack = !after(start_seq, TCP_SKB_CB(skb)->seq); |
| 1425 | if (!in_sack) { |
| 1426 | /* TODO: head merge to next could be attempted here |
| 1427 | * if (!after(TCP_SKB_CB(skb)->end_seq, end_seq)), |
| 1428 | * though it might not be worth of the additional hassle |
| 1429 | * |
| 1430 | * ...we can probably just fallback to what was done |
| 1431 | * previously. We could try merging non-SACKed ones |
| 1432 | * as well but it probably isn't going to buy off |
| 1433 | * because later SACKs might again split them, and |
| 1434 | * it would make skb timestamp tracking considerably |
| 1435 | * harder problem. |
| 1436 | */ |
| 1437 | goto fallback; |
| 1438 | } |
| 1439 | |
| 1440 | len = end_seq - TCP_SKB_CB(skb)->seq; |
| 1441 | BUG_ON(len < 0); |
| 1442 | BUG_ON(len > skb->len); |
| 1443 | |
| 1444 | /* MSS boundaries should be honoured or else pcount will |
| 1445 | * severely break even though it makes things bit trickier. |
| 1446 | * Optimize common case to avoid most of the divides |
| 1447 | */ |
| 1448 | mss = tcp_skb_mss(skb); |
| 1449 | |
| 1450 | /* TODO: Fix DSACKs to not fragment already SACKed and we can |
| 1451 | * drop this restriction as unnecessary |
| 1452 | */ |
Ilpo Järvinen | 775ffab | 2008-12-05 22:41:26 -0800 | [diff] [blame] | 1453 | if (mss != tcp_skb_seglen(prev)) |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1454 | goto fallback; |
| 1455 | |
| 1456 | if (len == mss) { |
| 1457 | pcount = 1; |
| 1458 | } else if (len < mss) { |
| 1459 | goto noop; |
| 1460 | } else { |
| 1461 | pcount = len / mss; |
| 1462 | len = pcount * mss; |
| 1463 | } |
| 1464 | } |
| 1465 | |
Neal Cardwell | 4648dc9 | 2012-03-05 19:35:04 +0000 | [diff] [blame] | 1466 | /* tcp_sacktag_one() won't SACK-tag ranges below snd_una */ |
| 1467 | if (!after(TCP_SKB_CB(skb)->seq + len, tp->snd_una)) |
| 1468 | goto fallback; |
| 1469 | |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1470 | if (!skb_shift(prev, skb, len)) |
| 1471 | goto fallback; |
Eric Dumazet | f331981 | 2017-10-05 22:21:26 -0700 | [diff] [blame] | 1472 | if (!tcp_shifted_skb(sk, prev, skb, state, pcount, len, mss, dup_sack)) |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1473 | goto out; |
| 1474 | |
| 1475 | /* Hole filled allows collapsing with the next as well, this is very |
| 1476 | * useful when hole on every nth skb pattern happens |
| 1477 | */ |
Eric Dumazet | 75c119a | 2017-10-05 22:21:27 -0700 | [diff] [blame] | 1478 | skb = skb_rb_next(prev); |
| 1479 | if (!skb) |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1480 | goto out; |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1481 | |
Ilpo Järvinen | f0bc52f | 2008-12-05 22:40:47 -0800 | [diff] [blame] | 1482 | if (!skb_can_shift(skb) || |
Ilpo Järvinen | f0bc52f | 2008-12-05 22:40:47 -0800 | [diff] [blame] | 1483 | ((TCP_SKB_CB(skb)->sacked & TCPCB_TAGBITS) != TCPCB_SACKED_ACKED) || |
Ilpo Järvinen | 775ffab | 2008-12-05 22:41:26 -0800 | [diff] [blame] | 1484 | (mss != tcp_skb_seglen(skb))) |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1485 | goto out; |
| 1486 | |
| 1487 | len = skb->len; |
| 1488 | if (skb_shift(prev, skb, len)) { |
| 1489 | pcount += tcp_skb_pcount(skb); |
Eric Dumazet | f331981 | 2017-10-05 22:21:26 -0700 | [diff] [blame] | 1490 | tcp_shifted_skb(sk, prev, skb, state, tcp_skb_pcount(skb), |
| 1491 | len, mss, 0); |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1492 | } |
| 1493 | |
| 1494 | out: |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1495 | return prev; |
| 1496 | |
| 1497 | noop: |
| 1498 | return skb; |
| 1499 | |
| 1500 | fallback: |
Eric Dumazet | c10d931 | 2016-04-29 14:16:47 -0700 | [diff] [blame] | 1501 | NET_INC_STATS(sock_net(sk), LINUX_MIB_SACKSHIFTFALLBACK); |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1502 | return NULL; |
| 1503 | } |
| 1504 | |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1505 | static struct sk_buff *tcp_sacktag_walk(struct sk_buff *skb, struct sock *sk, |
| 1506 | struct tcp_sack_block *next_dup, |
Ilpo Järvinen | a1197f5 | 2008-12-05 22:42:22 -0800 | [diff] [blame] | 1507 | struct tcp_sacktag_state *state, |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1508 | u32 start_seq, u32 end_seq, |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 1509 | bool dup_sack_in) |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1510 | { |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1511 | struct tcp_sock *tp = tcp_sk(sk); |
| 1512 | struct sk_buff *tmp; |
| 1513 | |
Eric Dumazet | 75c119a | 2017-10-05 22:21:27 -0700 | [diff] [blame] | 1514 | skb_rbtree_walk_from(skb) { |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1515 | int in_sack = 0; |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 1516 | bool dup_sack = dup_sack_in; |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1517 | |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1518 | /* queue is in-order => we can short-circuit the walk early */ |
| 1519 | if (!before(TCP_SKB_CB(skb)->seq, end_seq)) |
| 1520 | break; |
| 1521 | |
Ian Morris | 00db412 | 2015-04-03 09:17:27 +0100 | [diff] [blame] | 1522 | if (next_dup && |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1523 | before(TCP_SKB_CB(skb)->seq, next_dup->end_seq)) { |
| 1524 | in_sack = tcp_match_skb_to_sack(sk, skb, |
| 1525 | next_dup->start_seq, |
| 1526 | next_dup->end_seq); |
| 1527 | if (in_sack > 0) |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 1528 | dup_sack = true; |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1529 | } |
| 1530 | |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1531 | /* skb reference here is a bit tricky to get right, since |
| 1532 | * shifting can eat and free both this skb and the next, |
| 1533 | * so not even _safe variant of the loop is enough. |
| 1534 | */ |
| 1535 | if (in_sack <= 0) { |
Ilpo Järvinen | a1197f5 | 2008-12-05 22:42:22 -0800 | [diff] [blame] | 1536 | tmp = tcp_shift_skb_data(sk, skb, state, |
| 1537 | start_seq, end_seq, dup_sack); |
Ian Morris | 00db412 | 2015-04-03 09:17:27 +0100 | [diff] [blame] | 1538 | if (tmp) { |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1539 | if (tmp != skb) { |
| 1540 | skb = tmp; |
| 1541 | continue; |
| 1542 | } |
| 1543 | |
| 1544 | in_sack = 0; |
| 1545 | } else { |
| 1546 | in_sack = tcp_match_skb_to_sack(sk, skb, |
| 1547 | start_seq, |
| 1548 | end_seq); |
| 1549 | } |
| 1550 | } |
| 1551 | |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1552 | if (unlikely(in_sack < 0)) |
| 1553 | break; |
| 1554 | |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1555 | if (in_sack) { |
Neal Cardwell | cc9a672 | 2012-02-12 18:37:09 +0000 | [diff] [blame] | 1556 | TCP_SKB_CB(skb)->sacked = |
| 1557 | tcp_sacktag_one(sk, |
| 1558 | state, |
| 1559 | TCP_SKB_CB(skb)->sacked, |
| 1560 | TCP_SKB_CB(skb)->seq, |
| 1561 | TCP_SKB_CB(skb)->end_seq, |
| 1562 | dup_sack, |
Yuchung Cheng | 59c9af4 | 2013-07-22 16:20:47 -0700 | [diff] [blame] | 1563 | tcp_skb_pcount(skb), |
Eric Dumazet | 2fd66ff | 2018-09-21 08:51:47 -0700 | [diff] [blame] | 1564 | tcp_skb_timestamp_us(skb)); |
Yuchung Cheng | b9f6482 | 2016-09-19 23:39:14 -0400 | [diff] [blame] | 1565 | tcp_rate_skb_delivered(sk, skb, state->rate); |
Eric Dumazet | e208007 | 2017-10-04 12:59:58 -0700 | [diff] [blame] | 1566 | if (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED) |
| 1567 | list_del_init(&skb->tcp_tsorted_anchor); |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1568 | |
Ilpo Järvinen | 832d11c | 2008-11-24 21:20:15 -0800 | [diff] [blame] | 1569 | if (!before(TCP_SKB_CB(skb)->seq, |
| 1570 | tcp_highest_sack_seq(tp))) |
| 1571 | tcp_advance_highest_sack(sk, skb); |
| 1572 | } |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1573 | } |
| 1574 | return skb; |
| 1575 | } |
| 1576 | |
Taehee Yoo | 4bfabc4 | 2019-02-25 18:42:33 +0900 | [diff] [blame] | 1577 | static struct sk_buff *tcp_sacktag_bsearch(struct sock *sk, u32 seq) |
Eric Dumazet | 75c119a | 2017-10-05 22:21:27 -0700 | [diff] [blame] | 1578 | { |
| 1579 | struct rb_node *parent, **p = &sk->tcp_rtx_queue.rb_node; |
| 1580 | struct sk_buff *skb; |
Eric Dumazet | 75c119a | 2017-10-05 22:21:27 -0700 | [diff] [blame] | 1581 | |
| 1582 | while (*p) { |
| 1583 | parent = *p; |
| 1584 | skb = rb_to_skb(parent); |
| 1585 | if (before(seq, TCP_SKB_CB(skb)->seq)) { |
| 1586 | p = &parent->rb_left; |
| 1587 | continue; |
| 1588 | } |
| 1589 | if (!before(seq, TCP_SKB_CB(skb)->end_seq)) { |
| 1590 | p = &parent->rb_right; |
| 1591 | continue; |
| 1592 | } |
Eric Dumazet | 75c119a | 2017-10-05 22:21:27 -0700 | [diff] [blame] | 1593 | return skb; |
| 1594 | } |
| 1595 | return NULL; |
| 1596 | } |
| 1597 | |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1598 | static struct sk_buff *tcp_sacktag_skip(struct sk_buff *skb, struct sock *sk, |
Ilpo Järvinen | a1197f5 | 2008-12-05 22:42:22 -0800 | [diff] [blame] | 1599 | u32 skip_to_seq) |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1600 | { |
Eric Dumazet | 75c119a | 2017-10-05 22:21:27 -0700 | [diff] [blame] | 1601 | if (skb && after(TCP_SKB_CB(skb)->seq, skip_to_seq)) |
| 1602 | return skb; |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1603 | |
Taehee Yoo | 4bfabc4 | 2019-02-25 18:42:33 +0900 | [diff] [blame] | 1604 | return tcp_sacktag_bsearch(sk, skip_to_seq); |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1605 | } |
| 1606 | |
| 1607 | static struct sk_buff *tcp_maybe_skipping_dsack(struct sk_buff *skb, |
| 1608 | struct sock *sk, |
| 1609 | struct tcp_sack_block *next_dup, |
Ilpo Järvinen | a1197f5 | 2008-12-05 22:42:22 -0800 | [diff] [blame] | 1610 | struct tcp_sacktag_state *state, |
| 1611 | u32 skip_to_seq) |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1612 | { |
Ian Morris | 51456b2 | 2015-04-03 09:17:26 +0100 | [diff] [blame] | 1613 | if (!next_dup) |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1614 | return skb; |
| 1615 | |
| 1616 | if (before(next_dup->start_seq, skip_to_seq)) { |
Taehee Yoo | 4bfabc4 | 2019-02-25 18:42:33 +0900 | [diff] [blame] | 1617 | skb = tcp_sacktag_skip(skb, sk, next_dup->start_seq); |
Ilpo Järvinen | a1197f5 | 2008-12-05 22:42:22 -0800 | [diff] [blame] | 1618 | skb = tcp_sacktag_walk(skb, sk, NULL, state, |
| 1619 | next_dup->start_seq, next_dup->end_seq, |
| 1620 | 1); |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1621 | } |
| 1622 | |
| 1623 | return skb; |
| 1624 | } |
| 1625 | |
Eric Dumazet | cf533ea | 2011-10-21 05:22:42 -0400 | [diff] [blame] | 1626 | static int tcp_sack_cache_ok(const struct tcp_sock *tp, const struct tcp_sack_block *cache) |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1627 | { |
| 1628 | return cache < tp->recv_sack_cache + ARRAY_SIZE(tp->recv_sack_cache); |
| 1629 | } |
| 1630 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1631 | static int |
Eric Dumazet | cf533ea | 2011-10-21 05:22:42 -0400 | [diff] [blame] | 1632 | tcp_sacktag_write_queue(struct sock *sk, const struct sk_buff *ack_skb, |
Kenneth Klette Jonassen | 196da97 | 2015-05-01 01:10:57 +0200 | [diff] [blame] | 1633 | u32 prior_snd_una, struct tcp_sacktag_state *state) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1634 | { |
| 1635 | struct tcp_sock *tp = tcp_sk(sk); |
Eric Dumazet | cf533ea | 2011-10-21 05:22:42 -0400 | [diff] [blame] | 1636 | const unsigned char *ptr = (skb_transport_header(ack_skb) + |
| 1637 | TCP_SKB_CB(ack_skb)->sacked); |
Ilpo Järvinen | fd6dad6 | 2007-11-15 19:49:47 -0800 | [diff] [blame] | 1638 | struct tcp_sack_block_wire *sp_wire = (struct tcp_sack_block_wire *)(ptr+2); |
Adam Langley | 4389dde | 2008-07-19 00:07:02 -0700 | [diff] [blame] | 1639 | struct tcp_sack_block sp[TCP_NUM_SACKS]; |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1640 | struct tcp_sack_block *cache; |
| 1641 | struct sk_buff *skb; |
Adam Langley | 4389dde | 2008-07-19 00:07:02 -0700 | [diff] [blame] | 1642 | int num_sacks = min(TCP_NUM_SACKS, (ptr[1] - TCPOLEN_SACK_BASE) >> 3); |
Ilpo Järvinen | fd6dad6 | 2007-11-15 19:49:47 -0800 | [diff] [blame] | 1643 | int used_sacks; |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 1644 | bool found_dup_sack = false; |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1645 | int i, j; |
Baruch Even | fda03fb | 2007-02-04 23:35:57 -0800 | [diff] [blame] | 1646 | int first_sack_index; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1647 | |
Kenneth Klette Jonassen | 196da97 | 2015-05-01 01:10:57 +0200 | [diff] [blame] | 1648 | state->flag = 0; |
Yuchung Cheng | 737ff31 | 2017-11-08 13:01:27 -0800 | [diff] [blame] | 1649 | state->reord = tp->snd_nxt; |
Ilpo Järvinen | a1197f5 | 2008-12-05 22:42:22 -0800 | [diff] [blame] | 1650 | |
Yuchung Cheng | 737ff31 | 2017-11-08 13:01:27 -0800 | [diff] [blame] | 1651 | if (!tp->sacked_out) |
Ilpo Järvinen | 6859d49 | 2007-12-02 00:48:06 +0200 | [diff] [blame] | 1652 | tcp_highest_sack_reset(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1653 | |
Pavel Emelyanov | 1ed8346 | 2008-07-16 20:29:51 -0700 | [diff] [blame] | 1654 | found_dup_sack = tcp_check_dsack(sk, ack_skb, sp_wire, |
David S. Miller | d06e021 | 2007-06-18 22:43:06 -0700 | [diff] [blame] | 1655 | num_sacks, prior_snd_una); |
Yuchung Cheng | b9f6482 | 2016-09-19 23:39:14 -0400 | [diff] [blame] | 1656 | if (found_dup_sack) { |
Kenneth Klette Jonassen | 196da97 | 2015-05-01 01:10:57 +0200 | [diff] [blame] | 1657 | state->flag |= FLAG_DSACKING_ACK; |
Yuchung Cheng | b9f6482 | 2016-09-19 23:39:14 -0400 | [diff] [blame] | 1658 | tp->delivered++; /* A spurious retransmission is delivered */ |
| 1659 | } |
Baruch Even | 6f74651 | 2007-02-04 23:36:42 -0800 | [diff] [blame] | 1660 | |
| 1661 | /* Eliminate too old ACKs, but take into |
| 1662 | * account more or less fresh ones, they can |
| 1663 | * contain valid SACK info. |
| 1664 | */ |
| 1665 | if (before(TCP_SKB_CB(ack_skb)->ack_seq, prior_snd_una - tp->max_window)) |
| 1666 | return 0; |
| 1667 | |
Ilpo Järvinen | 96a2d41 | 2007-11-14 15:47:18 -0800 | [diff] [blame] | 1668 | if (!tp->packets_out) |
| 1669 | goto out; |
| 1670 | |
Ilpo Järvinen | fd6dad6 | 2007-11-15 19:49:47 -0800 | [diff] [blame] | 1671 | used_sacks = 0; |
| 1672 | first_sack_index = 0; |
| 1673 | for (i = 0; i < num_sacks; i++) { |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 1674 | bool dup_sack = !i && found_dup_sack; |
Ilpo Järvinen | fd6dad6 | 2007-11-15 19:49:47 -0800 | [diff] [blame] | 1675 | |
Harvey Harrison | d3e2ce3 | 2008-05-02 16:26:16 -0700 | [diff] [blame] | 1676 | sp[used_sacks].start_seq = get_unaligned_be32(&sp_wire[i].start_seq); |
| 1677 | sp[used_sacks].end_seq = get_unaligned_be32(&sp_wire[i].end_seq); |
Ilpo Järvinen | fd6dad6 | 2007-11-15 19:49:47 -0800 | [diff] [blame] | 1678 | |
| 1679 | if (!tcp_is_sackblock_valid(tp, dup_sack, |
| 1680 | sp[used_sacks].start_seq, |
| 1681 | sp[used_sacks].end_seq)) { |
Pavel Emelyanov | 40b215e | 2008-07-03 01:05:41 -0700 | [diff] [blame] | 1682 | int mib_idx; |
| 1683 | |
Ilpo Järvinen | fd6dad6 | 2007-11-15 19:49:47 -0800 | [diff] [blame] | 1684 | if (dup_sack) { |
| 1685 | if (!tp->undo_marker) |
Pavel Emelyanov | 40b215e | 2008-07-03 01:05:41 -0700 | [diff] [blame] | 1686 | mib_idx = LINUX_MIB_TCPDSACKIGNOREDNOUNDO; |
Ilpo Järvinen | fd6dad6 | 2007-11-15 19:49:47 -0800 | [diff] [blame] | 1687 | else |
Pavel Emelyanov | 40b215e | 2008-07-03 01:05:41 -0700 | [diff] [blame] | 1688 | mib_idx = LINUX_MIB_TCPDSACKIGNOREDOLD; |
Ilpo Järvinen | fd6dad6 | 2007-11-15 19:49:47 -0800 | [diff] [blame] | 1689 | } else { |
| 1690 | /* Don't count olds caused by ACK reordering */ |
| 1691 | if ((TCP_SKB_CB(ack_skb)->ack_seq != tp->snd_una) && |
| 1692 | !after(sp[used_sacks].end_seq, tp->snd_una)) |
| 1693 | continue; |
Pavel Emelyanov | 40b215e | 2008-07-03 01:05:41 -0700 | [diff] [blame] | 1694 | mib_idx = LINUX_MIB_TCPSACKDISCARD; |
Ilpo Järvinen | fd6dad6 | 2007-11-15 19:49:47 -0800 | [diff] [blame] | 1695 | } |
Pavel Emelyanov | 40b215e | 2008-07-03 01:05:41 -0700 | [diff] [blame] | 1696 | |
Eric Dumazet | c10d931 | 2016-04-29 14:16:47 -0700 | [diff] [blame] | 1697 | NET_INC_STATS(sock_net(sk), mib_idx); |
Ilpo Järvinen | fd6dad6 | 2007-11-15 19:49:47 -0800 | [diff] [blame] | 1698 | if (i == 0) |
| 1699 | first_sack_index = -1; |
| 1700 | continue; |
| 1701 | } |
| 1702 | |
| 1703 | /* Ignore very old stuff early */ |
| 1704 | if (!after(sp[used_sacks].end_seq, prior_snd_una)) |
| 1705 | continue; |
| 1706 | |
| 1707 | used_sacks++; |
| 1708 | } |
| 1709 | |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1710 | /* order SACK blocks to allow in order walk of the retrans queue */ |
| 1711 | for (i = used_sacks - 1; i > 0; i--) { |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 1712 | for (j = 0; j < i; j++) { |
| 1713 | if (after(sp[j].start_seq, sp[j + 1].start_seq)) { |
Ilpo Järvinen | a0bffff | 2009-03-21 13:36:17 -0700 | [diff] [blame] | 1714 | swap(sp[j], sp[j + 1]); |
Stephen Hemminger | 6a438bb | 2005-11-10 17:14:59 -0800 | [diff] [blame] | 1715 | |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1716 | /* Track where the first SACK block goes to */ |
| 1717 | if (j == first_sack_index) |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 1718 | first_sack_index = j + 1; |
Stephen Hemminger | 6a438bb | 2005-11-10 17:14:59 -0800 | [diff] [blame] | 1719 | } |
| 1720 | } |
| 1721 | } |
| 1722 | |
Eric Dumazet | 75c119a | 2017-10-05 22:21:27 -0700 | [diff] [blame] | 1723 | state->mss_now = tcp_current_mss(sk); |
Eric Dumazet | 75c119a | 2017-10-05 22:21:27 -0700 | [diff] [blame] | 1724 | skb = NULL; |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1725 | i = 0; |
| 1726 | |
| 1727 | if (!tp->sacked_out) { |
| 1728 | /* It's already past, so skip checking against it */ |
| 1729 | cache = tp->recv_sack_cache + ARRAY_SIZE(tp->recv_sack_cache); |
| 1730 | } else { |
| 1731 | cache = tp->recv_sack_cache; |
| 1732 | /* Skip empty blocks in at head of the cache */ |
| 1733 | while (tcp_sack_cache_ok(tp, cache) && !cache->start_seq && |
| 1734 | !cache->end_seq) |
| 1735 | cache++; |
Baruch Even | fda03fb | 2007-02-04 23:35:57 -0800 | [diff] [blame] | 1736 | } |
| 1737 | |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1738 | while (i < used_sacks) { |
Ilpo Järvinen | fd6dad6 | 2007-11-15 19:49:47 -0800 | [diff] [blame] | 1739 | u32 start_seq = sp[i].start_seq; |
| 1740 | u32 end_seq = sp[i].end_seq; |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 1741 | bool dup_sack = (found_dup_sack && (i == first_sack_index)); |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1742 | struct tcp_sack_block *next_dup = NULL; |
Ilpo Järvinen | e56d6cd | 2007-11-01 00:09:37 -0700 | [diff] [blame] | 1743 | |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1744 | if (found_dup_sack && ((i + 1) == first_sack_index)) |
| 1745 | next_dup = &sp[i + 1]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1746 | |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1747 | /* Skip too early cached blocks */ |
| 1748 | while (tcp_sack_cache_ok(tp, cache) && |
| 1749 | !before(start_seq, cache->end_seq)) |
| 1750 | cache++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1751 | |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1752 | /* Can skip some work by looking recv_sack_cache? */ |
| 1753 | if (tcp_sack_cache_ok(tp, cache) && !dup_sack && |
| 1754 | after(end_seq, cache->start_seq)) { |
David S. Miller | fe067e8 | 2007-03-07 12:12:44 -0800 | [diff] [blame] | 1755 | |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1756 | /* Head todo? */ |
| 1757 | if (before(start_seq, cache->start_seq)) { |
Taehee Yoo | 4bfabc4 | 2019-02-25 18:42:33 +0900 | [diff] [blame] | 1758 | skb = tcp_sacktag_skip(skb, sk, start_seq); |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 1759 | skb = tcp_sacktag_walk(skb, sk, next_dup, |
Kenneth Klette Jonassen | 196da97 | 2015-05-01 01:10:57 +0200 | [diff] [blame] | 1760 | state, |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 1761 | start_seq, |
| 1762 | cache->start_seq, |
Ilpo Järvinen | a1197f5 | 2008-12-05 22:42:22 -0800 | [diff] [blame] | 1763 | dup_sack); |
Baruch Even | fda03fb | 2007-02-04 23:35:57 -0800 | [diff] [blame] | 1764 | } |
Stephen Hemminger | 6a438bb | 2005-11-10 17:14:59 -0800 | [diff] [blame] | 1765 | |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1766 | /* Rest of the block already fully processed? */ |
Ilpo Järvinen | 20de20b | 2007-11-16 16:17:05 -0800 | [diff] [blame] | 1767 | if (!after(end_seq, cache->end_seq)) |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1768 | goto advance_sp; |
Ilpo Järvinen | 20de20b | 2007-11-16 16:17:05 -0800 | [diff] [blame] | 1769 | |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 1770 | skb = tcp_maybe_skipping_dsack(skb, sk, next_dup, |
Kenneth Klette Jonassen | 196da97 | 2015-05-01 01:10:57 +0200 | [diff] [blame] | 1771 | state, |
Ilpo Järvinen | a1197f5 | 2008-12-05 22:42:22 -0800 | [diff] [blame] | 1772 | cache->end_seq); |
Ilpo Järvinen | e56d6cd | 2007-11-01 00:09:37 -0700 | [diff] [blame] | 1773 | |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1774 | /* ...tail remains todo... */ |
Ilpo Järvinen | 6859d49 | 2007-12-02 00:48:06 +0200 | [diff] [blame] | 1775 | if (tcp_highest_sack_seq(tp) == cache->end_seq) { |
Ilpo Järvinen | 20de20b | 2007-11-16 16:17:05 -0800 | [diff] [blame] | 1776 | /* ...but better entrypoint exists! */ |
Ilpo Järvinen | 6859d49 | 2007-12-02 00:48:06 +0200 | [diff] [blame] | 1777 | skb = tcp_highest_sack(sk); |
Ian Morris | 51456b2 | 2015-04-03 09:17:26 +0100 | [diff] [blame] | 1778 | if (!skb) |
Ilpo Järvinen | 6859d49 | 2007-12-02 00:48:06 +0200 | [diff] [blame] | 1779 | break; |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1780 | cache++; |
| 1781 | goto walk; |
| 1782 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1783 | |
Taehee Yoo | 4bfabc4 | 2019-02-25 18:42:33 +0900 | [diff] [blame] | 1784 | skb = tcp_sacktag_skip(skb, sk, cache->end_seq); |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1785 | /* Check overlap against next cached too (past this one already) */ |
| 1786 | cache++; |
| 1787 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1788 | } |
Ilpo Järvinen | fbd52eb | 2007-11-10 21:24:19 -0800 | [diff] [blame] | 1789 | |
Ilpo Järvinen | 6859d49 | 2007-12-02 00:48:06 +0200 | [diff] [blame] | 1790 | if (!before(start_seq, tcp_highest_sack_seq(tp))) { |
| 1791 | skb = tcp_highest_sack(sk); |
Ian Morris | 51456b2 | 2015-04-03 09:17:26 +0100 | [diff] [blame] | 1792 | if (!skb) |
Ilpo Järvinen | 6859d49 | 2007-12-02 00:48:06 +0200 | [diff] [blame] | 1793 | break; |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1794 | } |
Taehee Yoo | 4bfabc4 | 2019-02-25 18:42:33 +0900 | [diff] [blame] | 1795 | skb = tcp_sacktag_skip(skb, sk, start_seq); |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1796 | |
| 1797 | walk: |
Kenneth Klette Jonassen | 196da97 | 2015-05-01 01:10:57 +0200 | [diff] [blame] | 1798 | skb = tcp_sacktag_walk(skb, sk, next_dup, state, |
Ilpo Järvinen | a1197f5 | 2008-12-05 22:42:22 -0800 | [diff] [blame] | 1799 | start_seq, end_seq, dup_sack); |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1800 | |
| 1801 | advance_sp: |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1802 | i++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1803 | } |
| 1804 | |
Ilpo Järvinen | 68f8353 | 2007-11-15 19:50:37 -0800 | [diff] [blame] | 1805 | /* Clear the head of the cache sack blocks so we can skip it next time */ |
| 1806 | for (i = 0; i < ARRAY_SIZE(tp->recv_sack_cache) - used_sacks; i++) { |
| 1807 | tp->recv_sack_cache[i].start_seq = 0; |
| 1808 | tp->recv_sack_cache[i].end_seq = 0; |
| 1809 | } |
| 1810 | for (j = 0; j < used_sacks; j++) |
| 1811 | tp->recv_sack_cache[i++] = sp[j]; |
| 1812 | |
Yuchung Cheng | 737ff31 | 2017-11-08 13:01:27 -0800 | [diff] [blame] | 1813 | if (inet_csk(sk)->icsk_ca_state != TCP_CA_Loss || tp->undo_marker) |
| 1814 | tcp_check_sack_reordering(sk, state->reord, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1815 | |
Yuchung Cheng | 9dac883 | 2015-04-29 11:28:30 -0700 | [diff] [blame] | 1816 | tcp_verify_left_out(tp); |
Ilpo Järvinen | 96a2d41 | 2007-11-14 15:47:18 -0800 | [diff] [blame] | 1817 | out: |
| 1818 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1819 | #if FASTRETRANS_DEBUG > 0 |
Ilpo Järvinen | 547b792 | 2008-07-25 21:43:18 -0700 | [diff] [blame] | 1820 | WARN_ON((int)tp->sacked_out < 0); |
| 1821 | WARN_ON((int)tp->lost_out < 0); |
| 1822 | WARN_ON((int)tp->retrans_out < 0); |
| 1823 | WARN_ON((int)tcp_packets_in_flight(tp) < 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1824 | #endif |
Kenneth Klette Jonassen | 196da97 | 2015-05-01 01:10:57 +0200 | [diff] [blame] | 1825 | return state->flag; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1826 | } |
| 1827 | |
Ilpo Järvinen | 882beba | 2008-04-07 22:33:07 -0700 | [diff] [blame] | 1828 | /* Limits sacked_out so that sum with lost_out isn't ever larger than |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 1829 | * packets_out. Returns false if sacked_out adjustement wasn't necessary. |
Ilpo Järvinen | 30935cf | 2007-02-21 23:01:36 -0800 | [diff] [blame] | 1830 | */ |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 1831 | static bool tcp_limit_reno_sacked(struct tcp_sock *tp) |
Ilpo Järvinen | 4ddf667 | 2007-05-27 01:52:00 -0700 | [diff] [blame] | 1832 | { |
Ilpo Järvinen | 4ddf667 | 2007-05-27 01:52:00 -0700 | [diff] [blame] | 1833 | u32 holes; |
| 1834 | |
| 1835 | holes = max(tp->lost_out, 1U); |
| 1836 | holes = min(holes, tp->packets_out); |
| 1837 | |
| 1838 | if ((tp->sacked_out + holes) > tp->packets_out) { |
| 1839 | tp->sacked_out = tp->packets_out - holes; |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 1840 | return true; |
Ilpo Järvinen | 4ddf667 | 2007-05-27 01:52:00 -0700 | [diff] [blame] | 1841 | } |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 1842 | return false; |
Ilpo Järvinen | 882beba | 2008-04-07 22:33:07 -0700 | [diff] [blame] | 1843 | } |
| 1844 | |
| 1845 | /* If we receive more dupacks than we expected counting segments |
| 1846 | * in assumption of absent reordering, interpret this as reordering. |
| 1847 | * The only another reason could be bug in receiver TCP. |
| 1848 | */ |
| 1849 | static void tcp_check_reno_reordering(struct sock *sk, const int addend) |
| 1850 | { |
| 1851 | struct tcp_sock *tp = tcp_sk(sk); |
Yuchung Cheng | 737ff31 | 2017-11-08 13:01:27 -0800 | [diff] [blame] | 1852 | |
| 1853 | if (!tcp_limit_reno_sacked(tp)) |
| 1854 | return; |
| 1855 | |
| 1856 | tp->reordering = min_t(u32, tp->packets_out + addend, |
| 1857 | sock_net(sk)->ipv4.sysctl_tcp_max_reordering); |
Wei Wang | 7ec6537 | 2018-07-31 17:46:24 -0700 | [diff] [blame] | 1858 | tp->reord_seen++; |
Yuchung Cheng | 737ff31 | 2017-11-08 13:01:27 -0800 | [diff] [blame] | 1859 | NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPRENOREORDER); |
Ilpo Järvinen | 4ddf667 | 2007-05-27 01:52:00 -0700 | [diff] [blame] | 1860 | } |
| 1861 | |
| 1862 | /* Emulate SACKs for SACKless connection: account for a new dupack. */ |
| 1863 | |
Eric Dumazet | 19119f2 | 2018-11-27 14:42:01 -0800 | [diff] [blame] | 1864 | static void tcp_add_reno_sack(struct sock *sk, int num_dupack) |
Ilpo Järvinen | 4ddf667 | 2007-05-27 01:52:00 -0700 | [diff] [blame] | 1865 | { |
Eric Dumazet | 19119f2 | 2018-11-27 14:42:01 -0800 | [diff] [blame] | 1866 | if (num_dupack) { |
| 1867 | struct tcp_sock *tp = tcp_sk(sk); |
| 1868 | u32 prior_sacked = tp->sacked_out; |
| 1869 | s32 delivered; |
Yuchung Cheng | ddf1af6 | 2016-02-02 10:33:06 -0800 | [diff] [blame] | 1870 | |
Eric Dumazet | 19119f2 | 2018-11-27 14:42:01 -0800 | [diff] [blame] | 1871 | tp->sacked_out += num_dupack; |
| 1872 | tcp_check_reno_reordering(sk, 0); |
| 1873 | delivered = tp->sacked_out - prior_sacked; |
| 1874 | if (delivered > 0) |
| 1875 | tp->delivered += delivered; |
| 1876 | tcp_verify_left_out(tp); |
| 1877 | } |
Ilpo Järvinen | 4ddf667 | 2007-05-27 01:52:00 -0700 | [diff] [blame] | 1878 | } |
| 1879 | |
| 1880 | /* Account for ACK, ACKing some data in Reno Recovery phase. */ |
| 1881 | |
| 1882 | static void tcp_remove_reno_sacks(struct sock *sk, int acked) |
| 1883 | { |
| 1884 | struct tcp_sock *tp = tcp_sk(sk); |
| 1885 | |
| 1886 | if (acked > 0) { |
| 1887 | /* One ACK acked hole. The rest eat duplicate ACKs. */ |
Yuchung Cheng | ddf1af6 | 2016-02-02 10:33:06 -0800 | [diff] [blame] | 1888 | tp->delivered += max_t(int, acked - tp->sacked_out, 1); |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 1889 | if (acked - 1 >= tp->sacked_out) |
Ilpo Järvinen | 4ddf667 | 2007-05-27 01:52:00 -0700 | [diff] [blame] | 1890 | tp->sacked_out = 0; |
| 1891 | else |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 1892 | tp->sacked_out -= acked - 1; |
Ilpo Järvinen | 4ddf667 | 2007-05-27 01:52:00 -0700 | [diff] [blame] | 1893 | } |
| 1894 | tcp_check_reno_reordering(sk, acked); |
Ilpo Järvinen | 005903b | 2007-08-09 14:44:16 +0300 | [diff] [blame] | 1895 | tcp_verify_left_out(tp); |
Ilpo Järvinen | 4ddf667 | 2007-05-27 01:52:00 -0700 | [diff] [blame] | 1896 | } |
| 1897 | |
| 1898 | static inline void tcp_reset_reno_sack(struct tcp_sock *tp) |
| 1899 | { |
| 1900 | tp->sacked_out = 0; |
Ilpo Järvinen | 4ddf667 | 2007-05-27 01:52:00 -0700 | [diff] [blame] | 1901 | } |
| 1902 | |
Yuchung Cheng | 989e04c | 2014-08-22 14:15:22 -0700 | [diff] [blame] | 1903 | void tcp_clear_retrans(struct tcp_sock *tp) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1904 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1905 | tp->retrans_out = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1906 | tp->lost_out = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1907 | tp->undo_marker = 0; |
Yuchung Cheng | 6e08d5e | 2014-07-02 12:07:16 -0700 | [diff] [blame] | 1908 | tp->undo_retrans = -1; |
Ilpo Järvinen | 4cd8299 | 2007-10-11 17:34:57 -0700 | [diff] [blame] | 1909 | tp->sacked_out = 0; |
| 1910 | } |
| 1911 | |
Yuchung Cheng | 989e04c | 2014-08-22 14:15:22 -0700 | [diff] [blame] | 1912 | static inline void tcp_init_undo(struct tcp_sock *tp) |
| 1913 | { |
| 1914 | tp->undo_marker = tp->snd_una; |
| 1915 | /* Retransmission still in flight may cause DSACKs later. */ |
| 1916 | tp->undo_retrans = tp->retrans_out ? : -1; |
| 1917 | } |
| 1918 | |
Yuchung Cheng | b8fef65 | 2018-05-16 16:40:16 -0700 | [diff] [blame] | 1919 | static bool tcp_is_rack(const struct sock *sk) |
| 1920 | { |
| 1921 | return sock_net(sk)->ipv4.sysctl_tcp_recovery & TCP_RACK_LOSS_DETECTION; |
| 1922 | } |
| 1923 | |
Yuchung Cheng | 2ad55f5 | 2018-05-16 16:40:14 -0700 | [diff] [blame] | 1924 | /* If we detect SACK reneging, forget all SACK information |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1925 | * and reset tags completely, otherwise preserve SACKs. If receiver |
| 1926 | * dropped its ofo queue, we will know this due to reneging detection. |
| 1927 | */ |
Yuchung Cheng | 2ad55f5 | 2018-05-16 16:40:14 -0700 | [diff] [blame] | 1928 | static void tcp_timeout_mark_lost(struct sock *sk) |
| 1929 | { |
| 1930 | struct tcp_sock *tp = tcp_sk(sk); |
Yuchung Cheng | 56f8c5d | 2018-05-16 16:40:17 -0700 | [diff] [blame] | 1931 | struct sk_buff *skb, *head; |
Yuchung Cheng | 2ad55f5 | 2018-05-16 16:40:14 -0700 | [diff] [blame] | 1932 | bool is_reneg; /* is receiver reneging on SACKs? */ |
| 1933 | |
Yuchung Cheng | 56f8c5d | 2018-05-16 16:40:17 -0700 | [diff] [blame] | 1934 | head = tcp_rtx_queue_head(sk); |
| 1935 | is_reneg = head && (TCP_SKB_CB(head)->sacked & TCPCB_SACKED_ACKED); |
Yuchung Cheng | 2ad55f5 | 2018-05-16 16:40:14 -0700 | [diff] [blame] | 1936 | if (is_reneg) { |
| 1937 | NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPSACKRENEGING); |
| 1938 | tp->sacked_out = 0; |
| 1939 | /* Mark SACK reneging until we recover from this loss event. */ |
| 1940 | tp->is_sack_reneg = 1; |
| 1941 | } else if (tcp_is_reno(tp)) { |
| 1942 | tcp_reset_reno_sack(tp); |
| 1943 | } |
| 1944 | |
Yuchung Cheng | 56f8c5d | 2018-05-16 16:40:17 -0700 | [diff] [blame] | 1945 | skb = head; |
Yuchung Cheng | 2ad55f5 | 2018-05-16 16:40:14 -0700 | [diff] [blame] | 1946 | skb_rbtree_walk_from(skb) { |
| 1947 | if (is_reneg) |
| 1948 | TCP_SKB_CB(skb)->sacked &= ~TCPCB_SACKED_ACKED; |
Yuchung Cheng | 56f8c5d | 2018-05-16 16:40:17 -0700 | [diff] [blame] | 1949 | else if (tcp_is_rack(sk) && skb != head && |
| 1950 | tcp_rack_skb_timeout(tp, skb, 0) > 0) |
| 1951 | continue; /* Don't mark recently sent ones lost yet */ |
Yuchung Cheng | 2ad55f5 | 2018-05-16 16:40:14 -0700 | [diff] [blame] | 1952 | tcp_mark_skb_lost(sk, skb); |
| 1953 | } |
| 1954 | tcp_verify_left_out(tp); |
| 1955 | tcp_clear_all_retrans_hints(tp); |
| 1956 | } |
| 1957 | |
| 1958 | /* Enter Loss state. */ |
Neal Cardwell | 5ae344c | 2014-08-04 19:12:29 -0400 | [diff] [blame] | 1959 | void tcp_enter_loss(struct sock *sk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1960 | { |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 1961 | const struct inet_connection_sock *icsk = inet_csk(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1962 | struct tcp_sock *tp = tcp_sk(sk); |
Nikolay Borisov | 1043e25 | 2016-02-03 09:46:52 +0200 | [diff] [blame] | 1963 | struct net *net = sock_net(sk); |
Yuchung Cheng | cc663f4 | 2017-04-07 11:42:05 -0700 | [diff] [blame] | 1964 | bool new_recovery = icsk->icsk_ca_state < TCP_CA_Recovery; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1965 | |
Yuchung Cheng | c77d62f | 2018-05-16 16:40:15 -0700 | [diff] [blame] | 1966 | tcp_timeout_mark_lost(sk); |
| 1967 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1968 | /* Reduce ssthresh if it has not yet been made inside this window. */ |
Yuchung Cheng | e33099f | 2013-03-20 13:33:00 +0000 | [diff] [blame] | 1969 | if (icsk->icsk_ca_state <= TCP_CA_Disorder || |
| 1970 | !after(tp->high_seq, tp->snd_una) || |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 1971 | (icsk->icsk_ca_state == TCP_CA_Loss && !icsk->icsk_retransmits)) { |
| 1972 | tp->prior_ssthresh = tcp_current_ssthresh(sk); |
Yuchung Cheng | 4faf783 | 2017-08-03 20:38:51 -0700 | [diff] [blame] | 1973 | tp->prior_cwnd = tp->snd_cwnd; |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 1974 | tp->snd_ssthresh = icsk->icsk_ca_ops->ssthresh(sk); |
| 1975 | tcp_ca_event(sk, CA_EVENT_LOSS); |
Yuchung Cheng | 989e04c | 2014-08-22 14:15:22 -0700 | [diff] [blame] | 1976 | tcp_init_undo(tp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1977 | } |
Yuchung Cheng | 56f8c5d | 2018-05-16 16:40:17 -0700 | [diff] [blame] | 1978 | tp->snd_cwnd = tcp_packets_in_flight(tp) + 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1979 | tp->snd_cwnd_cnt = 0; |
Eric Dumazet | c2203cf | 2017-05-16 14:00:04 -0700 | [diff] [blame] | 1980 | tp->snd_cwnd_stamp = tcp_jiffies32; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1981 | |
Yuchung Cheng | 74c181d | 2013-08-12 16:41:25 -0700 | [diff] [blame] | 1982 | /* Timeout in disordered state after receiving substantial DUPACKs |
| 1983 | * suggests that the degree of reordering is over-estimated. |
| 1984 | */ |
| 1985 | if (icsk->icsk_ca_state <= TCP_CA_Disorder && |
Nikolay Borisov | 1043e25 | 2016-02-03 09:46:52 +0200 | [diff] [blame] | 1986 | tp->sacked_out >= net->ipv4.sysctl_tcp_reordering) |
Yuchung Cheng | 74c181d | 2013-08-12 16:41:25 -0700 | [diff] [blame] | 1987 | tp->reordering = min_t(unsigned int, tp->reordering, |
Nikolay Borisov | 1043e25 | 2016-02-03 09:46:52 +0200 | [diff] [blame] | 1988 | net->ipv4.sysctl_tcp_reordering); |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 1989 | tcp_set_ca_state(sk, TCP_CA_Loss); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1990 | tp->high_seq = tp->snd_nxt; |
Florian Westphal | 735d383 | 2014-09-29 13:08:30 +0200 | [diff] [blame] | 1991 | tcp_ecn_queue_cwr(tp); |
Yuchung Cheng | e33099f | 2013-03-20 13:33:00 +0000 | [diff] [blame] | 1992 | |
Yuchung Cheng | cc663f4 | 2017-04-07 11:42:05 -0700 | [diff] [blame] | 1993 | /* F-RTO RFC5682 sec 3.1 step 1: retransmit SND.UNA if no previous |
| 1994 | * loss recovery is underway except recurring timeout(s) on |
| 1995 | * the same SND.UNA (sec 3.2). Disable F-RTO on path MTU probing |
Yuchung Cheng | e33099f | 2013-03-20 13:33:00 +0000 | [diff] [blame] | 1996 | */ |
Eric Dumazet | af9b69a | 2017-10-26 21:55:10 -0700 | [diff] [blame] | 1997 | tp->frto = net->ipv4.sysctl_tcp_frto && |
Yuchung Cheng | cc663f4 | 2017-04-07 11:42:05 -0700 | [diff] [blame] | 1998 | (new_recovery || icsk->icsk_retransmits) && |
| 1999 | !inet_csk(sk)->icsk_mtup.probe_size; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2000 | } |
| 2001 | |
Ilpo Järvinen | cadbd03 | 2007-12-31 04:49:21 -0800 | [diff] [blame] | 2002 | /* If ACK arrived pointing to a remembered SACK, it means that our |
| 2003 | * remembered SACKs do not reflect real state of receiver i.e. |
| 2004 | * receiver _host_ is heavily congested (or buggy). |
| 2005 | * |
Neal Cardwell | 5ae344c | 2014-08-04 19:12:29 -0400 | [diff] [blame] | 2006 | * To avoid big spurious retransmission bursts due to transient SACK |
| 2007 | * scoreboard oddities that look like reneging, we give the receiver a |
| 2008 | * little time (max(RTT/2, 10ms)) to send us some more ACKs that will |
| 2009 | * restore sanity to the SACK scoreboard. If the apparent reneging |
| 2010 | * persists until this RTO then we'll clear the SACK scoreboard. |
Ilpo Järvinen | cadbd03 | 2007-12-31 04:49:21 -0800 | [diff] [blame] | 2011 | */ |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 2012 | static bool tcp_check_sack_reneging(struct sock *sk, int flag) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2013 | { |
Ilpo Järvinen | cadbd03 | 2007-12-31 04:49:21 -0800 | [diff] [blame] | 2014 | if (flag & FLAG_SACK_RENEGING) { |
Neal Cardwell | 5ae344c | 2014-08-04 19:12:29 -0400 | [diff] [blame] | 2015 | struct tcp_sock *tp = tcp_sk(sk); |
| 2016 | unsigned long delay = max(usecs_to_jiffies(tp->srtt_us >> 4), |
| 2017 | msecs_to_jiffies(10)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2018 | |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 2019 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, |
Neal Cardwell | 5ae344c | 2014-08-04 19:12:29 -0400 | [diff] [blame] | 2020 | delay, TCP_RTO_MAX); |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 2021 | return true; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2022 | } |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 2023 | return false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2024 | } |
| 2025 | |
Ilpo Järvinen | 85cc391 | 2007-11-15 19:39:31 -0800 | [diff] [blame] | 2026 | /* Heurestics to calculate number of duplicate ACKs. There's no dupACKs |
| 2027 | * counter when SACK is enabled (without SACK, sacked_out is used for |
| 2028 | * that purpose). |
| 2029 | * |
Ilpo Järvinen | 85cc391 | 2007-11-15 19:39:31 -0800 | [diff] [blame] | 2030 | * With reordering, holes may still be in flight, so RFC3517 recovery |
| 2031 | * uses pure sacked_out (total number of SACKed segments) even though |
| 2032 | * it violates the RFC that uses duplicate ACKs, often these are equal |
| 2033 | * but when e.g. out-of-window ACKs or packet duplication occurs, |
| 2034 | * they differ. Since neither occurs due to loss, TCP should really |
| 2035 | * ignore them. |
| 2036 | */ |
Eric Dumazet | cf533ea | 2011-10-21 05:22:42 -0400 | [diff] [blame] | 2037 | static inline int tcp_dupack_heuristics(const struct tcp_sock *tp) |
Ilpo Järvinen | 85cc391 | 2007-11-15 19:39:31 -0800 | [diff] [blame] | 2038 | { |
Yuchung Cheng | 713bafe | 2017-11-08 13:01:26 -0800 | [diff] [blame] | 2039 | return tp->sacked_out + 1; |
Ilpo Järvinen | 85cc391 | 2007-11-15 19:39:31 -0800 | [diff] [blame] | 2040 | } |
| 2041 | |
Yuchung Cheng | 713bafe | 2017-11-08 13:01:26 -0800 | [diff] [blame] | 2042 | /* Linux NewReno/SACK/ECN state machine. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2043 | * -------------------------------------- |
| 2044 | * |
| 2045 | * "Open" Normal state, no dubious events, fast path. |
| 2046 | * "Disorder" In all the respects it is "Open", |
| 2047 | * but requires a bit more attention. It is entered when |
| 2048 | * we see some SACKs or dupacks. It is split of "Open" |
| 2049 | * mainly to move some processing from fast path to slow one. |
| 2050 | * "CWR" CWND was reduced due to some Congestion Notification event. |
| 2051 | * It can be ECN, ICMP source quench, local device congestion. |
| 2052 | * "Recovery" CWND was reduced, we are fast-retransmitting. |
| 2053 | * "Loss" CWND was reduced due to RTO timeout or SACK reneging. |
| 2054 | * |
| 2055 | * tcp_fastretrans_alert() is entered: |
| 2056 | * - each incoming ACK, if state is not "Open" |
| 2057 | * - when arrived ACK is unusual, namely: |
| 2058 | * * SACK |
| 2059 | * * Duplicate ACK. |
| 2060 | * * ECN ECE. |
| 2061 | * |
| 2062 | * Counting packets in flight is pretty simple. |
| 2063 | * |
| 2064 | * in_flight = packets_out - left_out + retrans_out |
| 2065 | * |
| 2066 | * packets_out is SND.NXT-SND.UNA counted in packets. |
| 2067 | * |
| 2068 | * retrans_out is number of retransmitted segments. |
| 2069 | * |
| 2070 | * left_out is number of segments left network, but not ACKed yet. |
| 2071 | * |
| 2072 | * left_out = sacked_out + lost_out |
| 2073 | * |
| 2074 | * sacked_out: Packets, which arrived to receiver out of order |
| 2075 | * and hence not ACKed. With SACKs this number is simply |
| 2076 | * amount of SACKed data. Even without SACKs |
| 2077 | * it is easy to give pretty reliable estimate of this number, |
| 2078 | * counting duplicate ACKs. |
| 2079 | * |
| 2080 | * lost_out: Packets lost by network. TCP has no explicit |
| 2081 | * "loss notification" feedback from network (for now). |
| 2082 | * It means that this number can be only _guessed_. |
| 2083 | * Actually, it is the heuristics to predict lossage that |
| 2084 | * distinguishes different algorithms. |
| 2085 | * |
| 2086 | * F.e. after RTO, when all the queue is considered as lost, |
| 2087 | * lost_out = packets_out and in_flight = retrans_out. |
| 2088 | * |
Yuchung Cheng | a0370b3 | 2017-01-12 22:11:36 -0800 | [diff] [blame] | 2089 | * Essentially, we have now a few algorithms detecting |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2090 | * lost packets. |
| 2091 | * |
Yuchung Cheng | a0370b3 | 2017-01-12 22:11:36 -0800 | [diff] [blame] | 2092 | * If the receiver supports SACK: |
| 2093 | * |
| 2094 | * RFC6675/3517: It is the conventional algorithm. A packet is |
| 2095 | * considered lost if the number of higher sequence packets |
| 2096 | * SACKed is greater than or equal the DUPACK thoreshold |
| 2097 | * (reordering). This is implemented in tcp_mark_head_lost and |
| 2098 | * tcp_update_scoreboard. |
| 2099 | * |
| 2100 | * RACK (draft-ietf-tcpm-rack-01): it is a newer algorithm |
| 2101 | * (2017-) that checks timing instead of counting DUPACKs. |
| 2102 | * Essentially a packet is considered lost if it's not S/ACKed |
| 2103 | * after RTT + reordering_window, where both metrics are |
| 2104 | * dynamically measured and adjusted. This is implemented in |
| 2105 | * tcp_rack_mark_lost. |
| 2106 | * |
Yuchung Cheng | a0370b3 | 2017-01-12 22:11:36 -0800 | [diff] [blame] | 2107 | * If the receiver does not support SACK: |
| 2108 | * |
| 2109 | * NewReno (RFC6582): in Recovery we assume that one segment |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2110 | * is lost (classic Reno). While we are in Recovery and |
| 2111 | * a partial ACK arrives, we assume that one more packet |
| 2112 | * is lost (NewReno). This heuristics are the same in NewReno |
| 2113 | * and SACK. |
| 2114 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2115 | * Really tricky (and requiring careful tuning) part of algorithm |
| 2116 | * is hidden in functions tcp_time_to_recover() and tcp_xmit_retransmit_queue(). |
| 2117 | * The first determines the moment _when_ we should reduce CWND and, |
| 2118 | * hence, slow down forward transmission. In fact, it determines the moment |
| 2119 | * when we decide that hole is caused by loss, rather than by a reorder. |
| 2120 | * |
| 2121 | * tcp_xmit_retransmit_queue() decides, _what_ we should retransmit to fill |
| 2122 | * holes, caused by lost packets. |
| 2123 | * |
| 2124 | * And the most logically complicated part of algorithm is undo |
| 2125 | * heuristics. We detect false retransmits due to both too early |
| 2126 | * fast retransmit (reordering) and underestimated RTO, analyzing |
| 2127 | * timestamps and D-SACKs. When we detect that some segments were |
| 2128 | * retransmitted by mistake and CWND reduction was wrong, we undo |
| 2129 | * window reduction and abort recovery phase. This logic is hidden |
| 2130 | * inside several functions named tcp_try_undo_<something>. |
| 2131 | */ |
| 2132 | |
| 2133 | /* This function decides, when we should leave Disordered state |
| 2134 | * and enter Recovery phase, reducing congestion window. |
| 2135 | * |
| 2136 | * Main question: may we further continue forward transmission |
| 2137 | * with the same cwnd? |
| 2138 | */ |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 2139 | static bool tcp_time_to_recover(struct sock *sk, int flag) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2140 | { |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 2141 | struct tcp_sock *tp = tcp_sk(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2142 | |
| 2143 | /* Trick#1: The loss is proven. */ |
| 2144 | if (tp->lost_out) |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 2145 | return true; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2146 | |
| 2147 | /* Not-A-Trick#2 : Classic rule... */ |
Yuchung Cheng | b38a51f | 2018-05-16 16:40:11 -0700 | [diff] [blame] | 2148 | if (!tcp_is_rack(sk) && tcp_dupack_heuristics(tp) > tp->reordering) |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 2149 | return true; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2150 | |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 2151 | return false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2152 | } |
| 2153 | |
Yuchung Cheng | 974c123 | 2012-01-19 14:42:21 +0000 | [diff] [blame] | 2154 | /* Detect loss in event "A" above by marking head of queue up as lost. |
Yuchung Cheng | 713bafe | 2017-11-08 13:01:26 -0800 | [diff] [blame] | 2155 | * For non-SACK(Reno) senders, the first "packets" number of segments |
Yuchung Cheng | 974c123 | 2012-01-19 14:42:21 +0000 | [diff] [blame] | 2156 | * are considered lost. For RFC3517 SACK, a segment is considered lost if it |
| 2157 | * has at least tp->reordering SACKed seqments above it; "packets" refers to |
| 2158 | * the maximum SACKed segments to pass before reaching this limit. |
Ilpo Järvinen | 85cc391 | 2007-11-15 19:39:31 -0800 | [diff] [blame] | 2159 | */ |
Ilpo Järvinen | 1fdb936 | 2010-10-14 01:42:30 +0000 | [diff] [blame] | 2160 | static void tcp_mark_head_lost(struct sock *sk, int packets, int mark_head) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2161 | { |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 2162 | struct tcp_sock *tp = tcp_sk(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2163 | struct sk_buff *skb; |
Neal Cardwell | d88270e | 2016-01-25 14:01:53 -0800 | [diff] [blame] | 2164 | int cnt, oldcnt, lost; |
Ilpo Järvinen | c137f3d | 2008-04-07 22:32:38 -0700 | [diff] [blame] | 2165 | unsigned int mss; |
Yuchung Cheng | 974c123 | 2012-01-19 14:42:21 +0000 | [diff] [blame] | 2166 | /* Use SACK to deduce losses of new sequences sent during recovery */ |
| 2167 | const u32 loss_high = tcp_is_sack(tp) ? tp->snd_nxt : tp->high_seq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2168 | |
Ilpo Järvinen | 547b792 | 2008-07-25 21:43:18 -0700 | [diff] [blame] | 2169 | WARN_ON(packets > tp->packets_out); |
Eric Dumazet | 5e76ee4 | 2017-10-05 22:21:24 -0700 | [diff] [blame] | 2170 | skb = tp->lost_skb_hint; |
| 2171 | if (skb) { |
Ilpo Järvinen | 1fdb936 | 2010-10-14 01:42:30 +0000 | [diff] [blame] | 2172 | /* Head already handled? */ |
Eric Dumazet | 5e76ee4 | 2017-10-05 22:21:24 -0700 | [diff] [blame] | 2173 | if (mark_head && after(TCP_SKB_CB(skb)->seq, tp->snd_una)) |
Ilpo Järvinen | 1fdb936 | 2010-10-14 01:42:30 +0000 | [diff] [blame] | 2174 | return; |
Eric Dumazet | 5e76ee4 | 2017-10-05 22:21:24 -0700 | [diff] [blame] | 2175 | cnt = tp->lost_cnt_hint; |
Stephen Hemminger | 6a438bb | 2005-11-10 17:14:59 -0800 | [diff] [blame] | 2176 | } else { |
Eric Dumazet | 75c119a | 2017-10-05 22:21:27 -0700 | [diff] [blame] | 2177 | skb = tcp_rtx_queue_head(sk); |
Stephen Hemminger | 6a438bb | 2005-11-10 17:14:59 -0800 | [diff] [blame] | 2178 | cnt = 0; |
| 2179 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2180 | |
Eric Dumazet | 75c119a | 2017-10-05 22:21:27 -0700 | [diff] [blame] | 2181 | skb_rbtree_walk_from(skb) { |
Stephen Hemminger | 6a438bb | 2005-11-10 17:14:59 -0800 | [diff] [blame] | 2182 | /* TODO: do this better */ |
| 2183 | /* this is not the most efficient way to do this... */ |
| 2184 | tp->lost_skb_hint = skb; |
| 2185 | tp->lost_cnt_hint = cnt; |
Ilpo Järvinen | 85cc391 | 2007-11-15 19:39:31 -0800 | [diff] [blame] | 2186 | |
Yuchung Cheng | 974c123 | 2012-01-19 14:42:21 +0000 | [diff] [blame] | 2187 | if (after(TCP_SKB_CB(skb)->end_seq, loss_high)) |
Ilpo Järvinen | c137f3d | 2008-04-07 22:32:38 -0700 | [diff] [blame] | 2188 | break; |
| 2189 | |
| 2190 | oldcnt = cnt; |
Yuchung Cheng | 713bafe | 2017-11-08 13:01:26 -0800 | [diff] [blame] | 2191 | if (tcp_is_reno(tp) || |
Ilpo Järvinen | 85cc391 | 2007-11-15 19:39:31 -0800 | [diff] [blame] | 2192 | (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED)) |
| 2193 | cnt += tcp_skb_pcount(skb); |
| 2194 | |
Ilpo Järvinen | c137f3d | 2008-04-07 22:32:38 -0700 | [diff] [blame] | 2195 | if (cnt > packets) { |
Yuchung Cheng | 713bafe | 2017-11-08 13:01:26 -0800 | [diff] [blame] | 2196 | if (tcp_is_sack(tp) || |
Neal Cardwell | c0638c2 | 2012-03-02 21:36:51 +0000 | [diff] [blame] | 2197 | (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED) || |
Yuchung Cheng | b3de7559 | 2010-09-24 13:22:06 +0000 | [diff] [blame] | 2198 | (oldcnt >= packets)) |
Ilpo Järvinen | c137f3d | 2008-04-07 22:32:38 -0700 | [diff] [blame] | 2199 | break; |
| 2200 | |
Eric Dumazet | f69ad29 | 2015-06-11 09:15:18 -0700 | [diff] [blame] | 2201 | mss = tcp_skb_mss(skb); |
Neal Cardwell | d88270e | 2016-01-25 14:01:53 -0800 | [diff] [blame] | 2202 | /* If needed, chop off the prefix to mark as lost. */ |
| 2203 | lost = (packets - oldcnt) * mss; |
| 2204 | if (lost < skb->len && |
Eric Dumazet | 75c119a | 2017-10-05 22:21:27 -0700 | [diff] [blame] | 2205 | tcp_fragment(sk, TCP_FRAG_IN_RTX_QUEUE, skb, |
| 2206 | lost, mss, GFP_ATOMIC) < 0) |
Ilpo Järvinen | c137f3d | 2008-04-07 22:32:38 -0700 | [diff] [blame] | 2207 | break; |
| 2208 | cnt = packets; |
| 2209 | } |
| 2210 | |
Ilpo Järvinen | 41ea36e | 2008-09-20 21:19:22 -0700 | [diff] [blame] | 2211 | tcp_skb_mark_lost(tp, skb); |
Ilpo Järvinen | 1fdb936 | 2010-10-14 01:42:30 +0000 | [diff] [blame] | 2212 | |
| 2213 | if (mark_head) |
| 2214 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2215 | } |
Ilpo Järvinen | 005903b | 2007-08-09 14:44:16 +0300 | [diff] [blame] | 2216 | tcp_verify_left_out(tp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2217 | } |
| 2218 | |
| 2219 | /* Account newly detected lost packet(s) */ |
| 2220 | |
Ilpo Järvinen | 85cc391 | 2007-11-15 19:39:31 -0800 | [diff] [blame] | 2221 | static void tcp_update_scoreboard(struct sock *sk, int fast_rexmit) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2222 | { |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 2223 | struct tcp_sock *tp = tcp_sk(sk); |
| 2224 | |
Yuchung Cheng | 6ac06ec | 2018-05-16 16:40:12 -0700 | [diff] [blame] | 2225 | if (tcp_is_sack(tp)) { |
Ilpo Järvinen | 85cc391 | 2007-11-15 19:39:31 -0800 | [diff] [blame] | 2226 | int sacked_upto = tp->sacked_out - tp->reordering; |
Ilpo Järvinen | 1fdb936 | 2010-10-14 01:42:30 +0000 | [diff] [blame] | 2227 | if (sacked_upto >= 0) |
| 2228 | tcp_mark_head_lost(sk, sacked_upto, 0); |
| 2229 | else if (fast_rexmit) |
| 2230 | tcp_mark_head_lost(sk, 1, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2231 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2232 | } |
| 2233 | |
Yuchung Cheng | 77c6312 | 2015-10-16 21:57:44 -0700 | [diff] [blame] | 2234 | static bool tcp_tsopt_ecr_before(const struct tcp_sock *tp, u32 when) |
| 2235 | { |
| 2236 | return tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr && |
| 2237 | before(tp->rx_opt.rcv_tsecr, when); |
| 2238 | } |
| 2239 | |
Yuchung Cheng | 659a8ad | 2015-10-16 21:57:46 -0700 | [diff] [blame] | 2240 | /* skb is spurious retransmitted if the returned timestamp echo |
| 2241 | * reply is prior to the skb transmission time |
| 2242 | */ |
| 2243 | static bool tcp_skb_spurious_retrans(const struct tcp_sock *tp, |
| 2244 | const struct sk_buff *skb) |
| 2245 | { |
| 2246 | return (TCP_SKB_CB(skb)->sacked & TCPCB_RETRANS) && |
| 2247 | tcp_tsopt_ecr_before(tp, tcp_skb_timestamp(skb)); |
| 2248 | } |
| 2249 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2250 | /* Nothing was retransmitted or returned timestamp is less |
| 2251 | * than timestamp of the first retransmission. |
| 2252 | */ |
Vijay Subramanian | 67b95bd | 2012-07-19 21:32:18 +0000 | [diff] [blame] | 2253 | static inline bool tcp_packet_delayed(const struct tcp_sock *tp) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2254 | { |
| 2255 | return !tp->retrans_stamp || |
Yuchung Cheng | 77c6312 | 2015-10-16 21:57:44 -0700 | [diff] [blame] | 2256 | tcp_tsopt_ecr_before(tp, tp->retrans_stamp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2257 | } |
| 2258 | |
| 2259 | /* Undo procedures. */ |
| 2260 | |
Marcelo Leitner | 1f37bf8 | 2014-11-04 17:15:08 -0200 | [diff] [blame] | 2261 | /* We can clear retrans_stamp when there are no retransmissions in the |
| 2262 | * window. It would seem that it is trivially available for us in |
| 2263 | * tp->retrans_out, however, that kind of assumptions doesn't consider |
| 2264 | * what will happen if errors occur when sending retransmission for the |
| 2265 | * second time. ...It could the that such segment has only |
| 2266 | * TCPCB_EVER_RETRANS set at the present time. It seems that checking |
| 2267 | * the head skb is enough except for some reneging corner cases that |
| 2268 | * are not worth the effort. |
| 2269 | * |
| 2270 | * Main reason for all this complexity is the fact that connection dying |
| 2271 | * time now depends on the validity of the retrans_stamp, in particular, |
| 2272 | * that successive retransmissions of a segment must not advance |
| 2273 | * retrans_stamp under any conditions. |
| 2274 | */ |
| 2275 | static bool tcp_any_retrans_done(const struct sock *sk) |
| 2276 | { |
| 2277 | const struct tcp_sock *tp = tcp_sk(sk); |
| 2278 | struct sk_buff *skb; |
| 2279 | |
| 2280 | if (tp->retrans_out) |
| 2281 | return true; |
| 2282 | |
Eric Dumazet | 75c119a | 2017-10-05 22:21:27 -0700 | [diff] [blame] | 2283 | skb = tcp_rtx_queue_head(sk); |
Marcelo Leitner | 1f37bf8 | 2014-11-04 17:15:08 -0200 | [diff] [blame] | 2284 | if (unlikely(skb && TCP_SKB_CB(skb)->sacked & TCPCB_EVER_RETRANS)) |
| 2285 | return true; |
| 2286 | |
| 2287 | return false; |
| 2288 | } |
| 2289 | |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 2290 | static void DBGUNDO(struct sock *sk, const char *msg) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2291 | { |
Joe Perches | 3934788 | 2017-09-10 19:02:25 -0700 | [diff] [blame] | 2292 | #if FASTRETRANS_DEBUG > 1 |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 2293 | struct tcp_sock *tp = tcp_sk(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2294 | struct inet_sock *inet = inet_sk(sk); |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 2295 | |
YOSHIFUJI Hideaki | 569508c | 2008-04-14 04:09:36 -0700 | [diff] [blame] | 2296 | if (sk->sk_family == AF_INET) { |
Joe Perches | 91df42b | 2012-05-15 14:11:54 +0000 | [diff] [blame] | 2297 | pr_debug("Undo %s %pI4/%u c%u l%u ss%u/%u p%u\n", |
| 2298 | msg, |
| 2299 | &inet->inet_daddr, ntohs(inet->inet_dport), |
| 2300 | tp->snd_cwnd, tcp_left_out(tp), |
| 2301 | tp->snd_ssthresh, tp->prior_ssthresh, |
| 2302 | tp->packets_out); |
YOSHIFUJI Hideaki | 569508c | 2008-04-14 04:09:36 -0700 | [diff] [blame] | 2303 | } |
Eric Dumazet | dfd56b8 | 2011-12-10 09:48:31 +0000 | [diff] [blame] | 2304 | #if IS_ENABLED(CONFIG_IPV6) |
YOSHIFUJI Hideaki | 569508c | 2008-04-14 04:09:36 -0700 | [diff] [blame] | 2305 | else if (sk->sk_family == AF_INET6) { |
Joe Perches | 91df42b | 2012-05-15 14:11:54 +0000 | [diff] [blame] | 2306 | pr_debug("Undo %s %pI6/%u c%u l%u ss%u/%u p%u\n", |
| 2307 | msg, |
Eric Dumazet | 019b1c9 | 2016-09-22 17:54:00 -0700 | [diff] [blame] | 2308 | &sk->sk_v6_daddr, ntohs(inet->inet_dport), |
Joe Perches | 91df42b | 2012-05-15 14:11:54 +0000 | [diff] [blame] | 2309 | tp->snd_cwnd, tcp_left_out(tp), |
| 2310 | tp->snd_ssthresh, tp->prior_ssthresh, |
| 2311 | tp->packets_out); |
YOSHIFUJI Hideaki | 569508c | 2008-04-14 04:09:36 -0700 | [diff] [blame] | 2312 | } |
| 2313 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2314 | #endif |
Joe Perches | 3934788 | 2017-09-10 19:02:25 -0700 | [diff] [blame] | 2315 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2316 | |
Yuchung Cheng | 7026b91 | 2013-05-29 14:20:13 +0000 | [diff] [blame] | 2317 | static void tcp_undo_cwnd_reduction(struct sock *sk, bool unmark_loss) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2318 | { |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 2319 | struct tcp_sock *tp = tcp_sk(sk); |
| 2320 | |
Yuchung Cheng | 6a63df4 | 2013-05-29 14:20:12 +0000 | [diff] [blame] | 2321 | if (unmark_loss) { |
| 2322 | struct sk_buff *skb; |
| 2323 | |
Eric Dumazet | 75c119a | 2017-10-05 22:21:27 -0700 | [diff] [blame] | 2324 | skb_rbtree_walk(skb, &sk->tcp_rtx_queue) { |
Yuchung Cheng | 6a63df4 | 2013-05-29 14:20:12 +0000 | [diff] [blame] | 2325 | TCP_SKB_CB(skb)->sacked &= ~TCPCB_LOST; |
| 2326 | } |
| 2327 | tp->lost_out = 0; |
| 2328 | tcp_clear_all_retrans_hints(tp); |
| 2329 | } |
| 2330 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2331 | if (tp->prior_ssthresh) { |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 2332 | const struct inet_connection_sock *icsk = inet_csk(sk); |
| 2333 | |
Florian Westphal | e979918 | 2016-11-21 14:18:38 +0100 | [diff] [blame] | 2334 | tp->snd_cwnd = icsk->icsk_ca_ops->undo_cwnd(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2335 | |
Yuchung Cheng | 7026b91 | 2013-05-29 14:20:13 +0000 | [diff] [blame] | 2336 | if (tp->prior_ssthresh > tp->snd_ssthresh) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2337 | tp->snd_ssthresh = tp->prior_ssthresh; |
Florian Westphal | 735d383 | 2014-09-29 13:08:30 +0200 | [diff] [blame] | 2338 | tcp_ecn_withdraw_cwr(tp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2339 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2340 | } |
Eric Dumazet | c2203cf | 2017-05-16 14:00:04 -0700 | [diff] [blame] | 2341 | tp->snd_cwnd_stamp = tcp_jiffies32; |
Yuchung Cheng | 7026b91 | 2013-05-29 14:20:13 +0000 | [diff] [blame] | 2342 | tp->undo_marker = 0; |
Yuchung Cheng | cd1fc85 | 2017-12-07 11:33:31 -0800 | [diff] [blame] | 2343 | tp->rack.advanced = 1; /* Force RACK to re-exam losses */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2344 | } |
| 2345 | |
Vijay Subramanian | 67b95bd | 2012-07-19 21:32:18 +0000 | [diff] [blame] | 2346 | static inline bool tcp_may_undo(const struct tcp_sock *tp) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2347 | { |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 2348 | return tp->undo_marker && (!tp->undo_retrans || tcp_packet_delayed(tp)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2349 | } |
| 2350 | |
| 2351 | /* People celebrate: "We love our President!" */ |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 2352 | static bool tcp_try_undo_recovery(struct sock *sk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2353 | { |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 2354 | struct tcp_sock *tp = tcp_sk(sk); |
| 2355 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2356 | if (tcp_may_undo(tp)) { |
Pavel Emelyanov | 40b215e | 2008-07-03 01:05:41 -0700 | [diff] [blame] | 2357 | int mib_idx; |
| 2358 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2359 | /* Happy end! We did not retransmit anything |
| 2360 | * or our original transmission succeeded. |
| 2361 | */ |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 2362 | DBGUNDO(sk, inet_csk(sk)->icsk_ca_state == TCP_CA_Loss ? "loss" : "retrans"); |
Yuchung Cheng | 7026b91 | 2013-05-29 14:20:13 +0000 | [diff] [blame] | 2363 | tcp_undo_cwnd_reduction(sk, false); |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 2364 | if (inet_csk(sk)->icsk_ca_state == TCP_CA_Loss) |
Pavel Emelyanov | 40b215e | 2008-07-03 01:05:41 -0700 | [diff] [blame] | 2365 | mib_idx = LINUX_MIB_TCPLOSSUNDO; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2366 | else |
Pavel Emelyanov | 40b215e | 2008-07-03 01:05:41 -0700 | [diff] [blame] | 2367 | mib_idx = LINUX_MIB_TCPFULLUNDO; |
| 2368 | |
Eric Dumazet | c10d931 | 2016-04-29 14:16:47 -0700 | [diff] [blame] | 2369 | NET_INC_STATS(sock_net(sk), mib_idx); |
Priyaranjan Jha | 1f25569 | 2017-11-03 16:38:48 -0700 | [diff] [blame] | 2370 | } else if (tp->rack.reo_wnd_persist) { |
| 2371 | tp->rack.reo_wnd_persist--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2372 | } |
Ilpo Järvinen | e60402d | 2007-08-09 15:14:46 +0300 | [diff] [blame] | 2373 | if (tp->snd_una == tp->high_seq && tcp_is_reno(tp)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2374 | /* Hold old state until something *above* high_seq |
| 2375 | * is ACKed. For Reno it is MUST to prevent false |
| 2376 | * fast retransmits (RFC2582). SACK TCP is safe. */ |
Marcelo Leitner | 1f37bf8 | 2014-11-04 17:15:08 -0200 | [diff] [blame] | 2377 | if (!tcp_any_retrans_done(sk)) |
| 2378 | tp->retrans_stamp = 0; |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 2379 | return true; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2380 | } |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 2381 | tcp_set_ca_state(sk, TCP_CA_Open); |
Yousuk Seung | d476175 | 2017-12-07 13:41:34 -0800 | [diff] [blame] | 2382 | tp->is_sack_reneg = 0; |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 2383 | return false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2384 | } |
| 2385 | |
| 2386 | /* Try to undo cwnd reduction, because D-SACKs acked all retransmitted data */ |
Yuchung Cheng | c7d9d6a | 2013-05-29 14:20:14 +0000 | [diff] [blame] | 2387 | static bool tcp_try_undo_dsack(struct sock *sk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2388 | { |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 2389 | struct tcp_sock *tp = tcp_sk(sk); |
| 2390 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2391 | if (tp->undo_marker && !tp->undo_retrans) { |
Priyaranjan Jha | 1f25569 | 2017-11-03 16:38:48 -0700 | [diff] [blame] | 2392 | tp->rack.reo_wnd_persist = min(TCP_RACK_RECOVERY_THRESH, |
| 2393 | tp->rack.reo_wnd_persist + 1); |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 2394 | DBGUNDO(sk, "D-SACK"); |
Yuchung Cheng | 7026b91 | 2013-05-29 14:20:13 +0000 | [diff] [blame] | 2395 | tcp_undo_cwnd_reduction(sk, false); |
Eric Dumazet | c10d931 | 2016-04-29 14:16:47 -0700 | [diff] [blame] | 2396 | NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPDSACKUNDO); |
Yuchung Cheng | c7d9d6a | 2013-05-29 14:20:14 +0000 | [diff] [blame] | 2397 | return true; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2398 | } |
Yuchung Cheng | c7d9d6a | 2013-05-29 14:20:14 +0000 | [diff] [blame] | 2399 | return false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2400 | } |
| 2401 | |
Yuchung Cheng | e33099f | 2013-03-20 13:33:00 +0000 | [diff] [blame] | 2402 | /* Undo during loss recovery after partial ACK or using F-RTO. */ |
| 2403 | static bool tcp_try_undo_loss(struct sock *sk, bool frto_undo) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2404 | { |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 2405 | struct tcp_sock *tp = tcp_sk(sk); |
| 2406 | |
Yuchung Cheng | e33099f | 2013-03-20 13:33:00 +0000 | [diff] [blame] | 2407 | if (frto_undo || tcp_may_undo(tp)) { |
Yuchung Cheng | 7026b91 | 2013-05-29 14:20:13 +0000 | [diff] [blame] | 2408 | tcp_undo_cwnd_reduction(sk, true); |
Stephen Hemminger | 6a438bb | 2005-11-10 17:14:59 -0800 | [diff] [blame] | 2409 | |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 2410 | DBGUNDO(sk, "partial loss"); |
Eric Dumazet | c10d931 | 2016-04-29 14:16:47 -0700 | [diff] [blame] | 2411 | NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPLOSSUNDO); |
Yuchung Cheng | e33099f | 2013-03-20 13:33:00 +0000 | [diff] [blame] | 2412 | if (frto_undo) |
Eric Dumazet | c10d931 | 2016-04-29 14:16:47 -0700 | [diff] [blame] | 2413 | NET_INC_STATS(sock_net(sk), |
Eric Dumazet | 02a1d6e | 2016-04-27 16:44:39 -0700 | [diff] [blame] | 2414 | LINUX_MIB_TCPSPURIOUSRTOS); |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 2415 | inet_csk(sk)->icsk_retransmits = 0; |
Yousuk Seung | d476175 | 2017-12-07 13:41:34 -0800 | [diff] [blame] | 2416 | if (frto_undo || tcp_is_sack(tp)) { |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 2417 | tcp_set_ca_state(sk, TCP_CA_Open); |
Yousuk Seung | d476175 | 2017-12-07 13:41:34 -0800 | [diff] [blame] | 2418 | tp->is_sack_reneg = 0; |
| 2419 | } |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 2420 | return true; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2421 | } |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 2422 | return false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2423 | } |
| 2424 | |
Yuchung Cheng | 3759824 | 2015-07-01 14:11:15 -0700 | [diff] [blame] | 2425 | /* The cwnd reduction in CWR and Recovery uses the PRR algorithm in RFC 6937. |
Yuchung Cheng | fb4d3d1 | 2012-09-02 17:38:03 +0000 | [diff] [blame] | 2426 | * It computes the number of packets to send (sndcnt) based on packets newly |
| 2427 | * delivered: |
| 2428 | * 1) If the packets in flight is larger than ssthresh, PRR spreads the |
| 2429 | * cwnd reductions across a full RTT. |
Yuchung Cheng | 3759824 | 2015-07-01 14:11:15 -0700 | [diff] [blame] | 2430 | * 2) Otherwise PRR uses packet conservation to send as much as delivered. |
| 2431 | * But when the retransmits are acked without further losses, PRR |
| 2432 | * slow starts cwnd up to ssthresh to speed up the recovery. |
Yuchung Cheng | fb4d3d1 | 2012-09-02 17:38:03 +0000 | [diff] [blame] | 2433 | */ |
Christoph Paasch | 5ee2c94 | 2014-07-14 16:58:32 +0200 | [diff] [blame] | 2434 | static void tcp_init_cwnd_reduction(struct sock *sk) |
Yuchung Cheng | 684bad1 | 2012-09-02 17:38:04 +0000 | [diff] [blame] | 2435 | { |
| 2436 | struct tcp_sock *tp = tcp_sk(sk); |
| 2437 | |
| 2438 | tp->high_seq = tp->snd_nxt; |
Nandita Dukkipati | 9b717a8 | 2013-03-11 10:00:44 +0000 | [diff] [blame] | 2439 | tp->tlp_high_seq = 0; |
Yuchung Cheng | 684bad1 | 2012-09-02 17:38:04 +0000 | [diff] [blame] | 2440 | tp->snd_cwnd_cnt = 0; |
| 2441 | tp->prior_cwnd = tp->snd_cwnd; |
| 2442 | tp->prr_delivered = 0; |
| 2443 | tp->prr_out = 0; |
Christoph Paasch | 5ee2c94 | 2014-07-14 16:58:32 +0200 | [diff] [blame] | 2444 | tp->snd_ssthresh = inet_csk(sk)->icsk_ca_ops->ssthresh(sk); |
Florian Westphal | 735d383 | 2014-09-29 13:08:30 +0200 | [diff] [blame] | 2445 | tcp_ecn_queue_cwr(tp); |
Yuchung Cheng | 684bad1 | 2012-09-02 17:38:04 +0000 | [diff] [blame] | 2446 | } |
| 2447 | |
Yuchung Cheng | 57dde7f | 2017-01-12 22:11:33 -0800 | [diff] [blame] | 2448 | void tcp_cwnd_reduction(struct sock *sk, int newly_acked_sacked, int flag) |
Yuchung Cheng | fb4d3d1 | 2012-09-02 17:38:03 +0000 | [diff] [blame] | 2449 | { |
| 2450 | struct tcp_sock *tp = tcp_sk(sk); |
| 2451 | int sndcnt = 0; |
| 2452 | int delta = tp->snd_ssthresh - tcp_packets_in_flight(tp); |
| 2453 | |
Yuchung Cheng | 8b8a321 | 2016-01-06 12:42:38 -0800 | [diff] [blame] | 2454 | if (newly_acked_sacked <= 0 || WARN_ON_ONCE(!tp->prior_cwnd)) |
| 2455 | return; |
| 2456 | |
Yuchung Cheng | 684bad1 | 2012-09-02 17:38:04 +0000 | [diff] [blame] | 2457 | tp->prr_delivered += newly_acked_sacked; |
Yuchung Cheng | 3759824 | 2015-07-01 14:11:15 -0700 | [diff] [blame] | 2458 | if (delta < 0) { |
Yuchung Cheng | fb4d3d1 | 2012-09-02 17:38:03 +0000 | [diff] [blame] | 2459 | u64 dividend = (u64)tp->snd_ssthresh * tp->prr_delivered + |
| 2460 | tp->prior_cwnd - 1; |
| 2461 | sndcnt = div_u64(dividend, tp->prior_cwnd) - tp->prr_out; |
Yafang Shao | 5e13a0d | 2018-11-11 20:10:10 +0800 | [diff] [blame] | 2462 | } else if ((flag & (FLAG_RETRANS_DATA_ACKED | FLAG_LOST_RETRANS)) == |
| 2463 | FLAG_RETRANS_DATA_ACKED) { |
Yuchung Cheng | fb4d3d1 | 2012-09-02 17:38:03 +0000 | [diff] [blame] | 2464 | sndcnt = min_t(int, delta, |
| 2465 | max_t(int, tp->prr_delivered - tp->prr_out, |
| 2466 | newly_acked_sacked) + 1); |
Yuchung Cheng | 3759824 | 2015-07-01 14:11:15 -0700 | [diff] [blame] | 2467 | } else { |
| 2468 | sndcnt = min(delta, newly_acked_sacked); |
Yuchung Cheng | fb4d3d1 | 2012-09-02 17:38:03 +0000 | [diff] [blame] | 2469 | } |
Yuchung Cheng | 31ba0c1 | 2016-02-02 10:33:05 -0800 | [diff] [blame] | 2470 | /* Force a fast retransmit upon entering fast recovery */ |
| 2471 | sndcnt = max(sndcnt, (tp->prr_out ? 0 : 1)); |
Yuchung Cheng | fb4d3d1 | 2012-09-02 17:38:03 +0000 | [diff] [blame] | 2472 | tp->snd_cwnd = tcp_packets_in_flight(tp) + sndcnt; |
| 2473 | } |
| 2474 | |
Yuchung Cheng | 684bad1 | 2012-09-02 17:38:04 +0000 | [diff] [blame] | 2475 | static inline void tcp_end_cwnd_reduction(struct sock *sk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2476 | { |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 2477 | struct tcp_sock *tp = tcp_sk(sk); |
Nandita Dukkipati | a262f0c | 2011-08-21 20:21:57 +0000 | [diff] [blame] | 2478 | |
Yuchung Cheng | c040276 | 2016-09-19 23:39:21 -0400 | [diff] [blame] | 2479 | if (inet_csk(sk)->icsk_ca_ops->cong_control) |
| 2480 | return; |
| 2481 | |
Yuchung Cheng | 684bad1 | 2012-09-02 17:38:04 +0000 | [diff] [blame] | 2482 | /* Reset cwnd to ssthresh in CWR or Recovery (unless it's undone) */ |
Yuchung Cheng | ed25497 | 2017-08-01 13:22:32 -0700 | [diff] [blame] | 2483 | if (tp->snd_ssthresh < TCP_INFINITE_SSTHRESH && |
| 2484 | (inet_csk(sk)->icsk_ca_state == TCP_CA_CWR || tp->undo_marker)) { |
Yuchung Cheng | 684bad1 | 2012-09-02 17:38:04 +0000 | [diff] [blame] | 2485 | tp->snd_cwnd = tp->snd_ssthresh; |
Eric Dumazet | c2203cf | 2017-05-16 14:00:04 -0700 | [diff] [blame] | 2486 | tp->snd_cwnd_stamp = tcp_jiffies32; |
Yuchung Cheng | 67d4120 | 2011-03-14 10:57:03 +0000 | [diff] [blame] | 2487 | } |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 2488 | tcp_ca_event(sk, CA_EVENT_COMPLETE_CWR); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2489 | } |
| 2490 | |
Yuchung Cheng | 684bad1 | 2012-09-02 17:38:04 +0000 | [diff] [blame] | 2491 | /* Enter CWR state. Disable cwnd undo since congestion is proven with ECN */ |
Christoph Paasch | 5ee2c94 | 2014-07-14 16:58:32 +0200 | [diff] [blame] | 2492 | void tcp_enter_cwr(struct sock *sk) |
Yuchung Cheng | 09484d1 | 2012-09-02 17:38:02 +0000 | [diff] [blame] | 2493 | { |
| 2494 | struct tcp_sock *tp = tcp_sk(sk); |
Yuchung Cheng | 09484d1 | 2012-09-02 17:38:02 +0000 | [diff] [blame] | 2495 | |
| 2496 | tp->prior_ssthresh = 0; |
Yuchung Cheng | 684bad1 | 2012-09-02 17:38:04 +0000 | [diff] [blame] | 2497 | if (inet_csk(sk)->icsk_ca_state < TCP_CA_CWR) { |
Yuchung Cheng | 09484d1 | 2012-09-02 17:38:02 +0000 | [diff] [blame] | 2498 | tp->undo_marker = 0; |
Christoph Paasch | 5ee2c94 | 2014-07-14 16:58:32 +0200 | [diff] [blame] | 2499 | tcp_init_cwnd_reduction(sk); |
Yuchung Cheng | 09484d1 | 2012-09-02 17:38:02 +0000 | [diff] [blame] | 2500 | tcp_set_ca_state(sk, TCP_CA_CWR); |
| 2501 | } |
| 2502 | } |
Kenneth Klette Jonassen | 7782ad8 | 2015-06-10 19:08:16 +0200 | [diff] [blame] | 2503 | EXPORT_SYMBOL(tcp_enter_cwr); |
Yuchung Cheng | 09484d1 | 2012-09-02 17:38:02 +0000 | [diff] [blame] | 2504 | |
Ilpo Järvinen | 8aca6cb | 2008-06-04 11:34:22 -0700 | [diff] [blame] | 2505 | static void tcp_try_keep_open(struct sock *sk) |
| 2506 | { |
| 2507 | struct tcp_sock *tp = tcp_sk(sk); |
| 2508 | int state = TCP_CA_Open; |
| 2509 | |
Neal Cardwell | f698204 | 2011-11-16 08:58:04 +0000 | [diff] [blame] | 2510 | if (tcp_left_out(tp) || tcp_any_retrans_done(sk)) |
Ilpo Järvinen | 8aca6cb | 2008-06-04 11:34:22 -0700 | [diff] [blame] | 2511 | state = TCP_CA_Disorder; |
| 2512 | |
| 2513 | if (inet_csk(sk)->icsk_ca_state != state) { |
| 2514 | tcp_set_ca_state(sk, state); |
| 2515 | tp->high_seq = tp->snd_nxt; |
| 2516 | } |
| 2517 | } |
| 2518 | |
Yuchung Cheng | 31ba0c1 | 2016-02-02 10:33:05 -0800 | [diff] [blame] | 2519 | static void tcp_try_to_open(struct sock *sk, int flag) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2520 | { |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 2521 | struct tcp_sock *tp = tcp_sk(sk); |
| 2522 | |
Ilpo Järvinen | 86426c2 | 2007-08-09 14:45:17 +0300 | [diff] [blame] | 2523 | tcp_verify_left_out(tp); |
| 2524 | |
Yuchung Cheng | 9b44190 | 2013-03-20 13:32:58 +0000 | [diff] [blame] | 2525 | if (!tcp_any_retrans_done(sk)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2526 | tp->retrans_stamp = 0; |
| 2527 | |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 2528 | if (flag & FLAG_ECE) |
Christoph Paasch | 5ee2c94 | 2014-07-14 16:58:32 +0200 | [diff] [blame] | 2529 | tcp_enter_cwr(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2530 | |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 2531 | if (inet_csk(sk)->icsk_ca_state != TCP_CA_CWR) { |
Ilpo Järvinen | 8aca6cb | 2008-06-04 11:34:22 -0700 | [diff] [blame] | 2532 | tcp_try_keep_open(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2533 | } |
| 2534 | } |
| 2535 | |
John Heffner | 5d424d5 | 2006-03-20 17:53:41 -0800 | [diff] [blame] | 2536 | static void tcp_mtup_probe_failed(struct sock *sk) |
| 2537 | { |
| 2538 | struct inet_connection_sock *icsk = inet_csk(sk); |
| 2539 | |
| 2540 | icsk->icsk_mtup.search_high = icsk->icsk_mtup.probe_size - 1; |
| 2541 | icsk->icsk_mtup.probe_size = 0; |
Eric Dumazet | c10d931 | 2016-04-29 14:16:47 -0700 | [diff] [blame] | 2542 | NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMTUPFAIL); |
John Heffner | 5d424d5 | 2006-03-20 17:53:41 -0800 | [diff] [blame] | 2543 | } |
| 2544 | |
Ilpo Järvinen | 72211e9 | 2009-03-14 14:23:04 +0000 | [diff] [blame] | 2545 | static void tcp_mtup_probe_success(struct sock *sk) |
John Heffner | 5d424d5 | 2006-03-20 17:53:41 -0800 | [diff] [blame] | 2546 | { |
| 2547 | struct tcp_sock *tp = tcp_sk(sk); |
| 2548 | struct inet_connection_sock *icsk = inet_csk(sk); |
| 2549 | |
| 2550 | /* FIXME: breaks with very large cwnd */ |
| 2551 | tp->prior_ssthresh = tcp_current_ssthresh(sk); |
| 2552 | tp->snd_cwnd = tp->snd_cwnd * |
| 2553 | tcp_mss_to_mtu(sk, tp->mss_cache) / |
| 2554 | icsk->icsk_mtup.probe_size; |
| 2555 | tp->snd_cwnd_cnt = 0; |
Eric Dumazet | c2203cf | 2017-05-16 14:00:04 -0700 | [diff] [blame] | 2556 | tp->snd_cwnd_stamp = tcp_jiffies32; |
John Heffner | 9c6d5e5 | 2010-10-06 21:18:02 -0700 | [diff] [blame] | 2557 | tp->snd_ssthresh = tcp_current_ssthresh(sk); |
John Heffner | 5d424d5 | 2006-03-20 17:53:41 -0800 | [diff] [blame] | 2558 | |
| 2559 | icsk->icsk_mtup.search_low = icsk->icsk_mtup.probe_size; |
| 2560 | icsk->icsk_mtup.probe_size = 0; |
| 2561 | tcp_sync_mss(sk, icsk->icsk_pmtu_cookie); |
Eric Dumazet | c10d931 | 2016-04-29 14:16:47 -0700 | [diff] [blame] | 2562 | NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMTUPSUCCESS); |
John Heffner | 5d424d5 | 2006-03-20 17:53:41 -0800 | [diff] [blame] | 2563 | } |
| 2564 | |
Ilpo Järvinen | e1aa680 | 2008-11-24 21:11:55 -0800 | [diff] [blame] | 2565 | /* Do a simple retransmit without using the backoff mechanisms in |
| 2566 | * tcp_timer. This is used for path mtu discovery. |
| 2567 | * The socket is already locked here. |
| 2568 | */ |
| 2569 | void tcp_simple_retransmit(struct sock *sk) |
| 2570 | { |
| 2571 | const struct inet_connection_sock *icsk = inet_csk(sk); |
| 2572 | struct tcp_sock *tp = tcp_sk(sk); |
| 2573 | struct sk_buff *skb; |
Ilpo Järvinen | 0c54b85 | 2009-03-14 14:23:05 +0000 | [diff] [blame] | 2574 | unsigned int mss = tcp_current_mss(sk); |
Ilpo Järvinen | e1aa680 | 2008-11-24 21:11:55 -0800 | [diff] [blame] | 2575 | |
Eric Dumazet | 75c119a | 2017-10-05 22:21:27 -0700 | [diff] [blame] | 2576 | skb_rbtree_walk(skb, &sk->tcp_rtx_queue) { |
Ilpo Järvinen | 775ffab | 2008-12-05 22:41:26 -0800 | [diff] [blame] | 2577 | if (tcp_skb_seglen(skb) > mss && |
Ilpo Järvinen | e1aa680 | 2008-11-24 21:11:55 -0800 | [diff] [blame] | 2578 | !(TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED)) { |
| 2579 | if (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_RETRANS) { |
| 2580 | TCP_SKB_CB(skb)->sacked &= ~TCPCB_SACKED_RETRANS; |
| 2581 | tp->retrans_out -= tcp_skb_pcount(skb); |
| 2582 | } |
| 2583 | tcp_skb_mark_lost_uncond_verify(tp, skb); |
| 2584 | } |
| 2585 | } |
| 2586 | |
| 2587 | tcp_clear_retrans_hints_partial(tp); |
| 2588 | |
Yuchung Cheng | 0eb96bf | 2017-11-07 15:33:43 -0800 | [diff] [blame] | 2589 | if (!tp->lost_out) |
Ilpo Järvinen | e1aa680 | 2008-11-24 21:11:55 -0800 | [diff] [blame] | 2590 | return; |
| 2591 | |
| 2592 | if (tcp_is_reno(tp)) |
| 2593 | tcp_limit_reno_sacked(tp); |
| 2594 | |
| 2595 | tcp_verify_left_out(tp); |
| 2596 | |
| 2597 | /* Don't muck with the congestion window here. |
| 2598 | * Reason is that we do not increase amount of _data_ |
| 2599 | * in network, but units changed and effective |
| 2600 | * cwnd/ssthresh really reduced now. |
| 2601 | */ |
| 2602 | if (icsk->icsk_ca_state != TCP_CA_Loss) { |
| 2603 | tp->high_seq = tp->snd_nxt; |
| 2604 | tp->snd_ssthresh = tcp_current_ssthresh(sk); |
| 2605 | tp->prior_ssthresh = 0; |
| 2606 | tp->undo_marker = 0; |
| 2607 | tcp_set_ca_state(sk, TCP_CA_Loss); |
| 2608 | } |
| 2609 | tcp_xmit_retransmit_queue(sk); |
| 2610 | } |
Eric Dumazet | 4bc2f18 | 2010-07-09 21:22:10 +0000 | [diff] [blame] | 2611 | EXPORT_SYMBOL(tcp_simple_retransmit); |
Ilpo Järvinen | e1aa680 | 2008-11-24 21:11:55 -0800 | [diff] [blame] | 2612 | |
Yuchung Cheng | 57dde7f | 2017-01-12 22:11:33 -0800 | [diff] [blame] | 2613 | void tcp_enter_recovery(struct sock *sk, bool ece_ack) |
Yuchung Cheng | 1fbc340 | 2012-05-02 13:30:02 +0000 | [diff] [blame] | 2614 | { |
| 2615 | struct tcp_sock *tp = tcp_sk(sk); |
| 2616 | int mib_idx; |
| 2617 | |
| 2618 | if (tcp_is_reno(tp)) |
| 2619 | mib_idx = LINUX_MIB_TCPRENORECOVERY; |
| 2620 | else |
| 2621 | mib_idx = LINUX_MIB_TCPSACKRECOVERY; |
| 2622 | |
Eric Dumazet | c10d931 | 2016-04-29 14:16:47 -0700 | [diff] [blame] | 2623 | NET_INC_STATS(sock_net(sk), mib_idx); |
Yuchung Cheng | 1fbc340 | 2012-05-02 13:30:02 +0000 | [diff] [blame] | 2624 | |
Yuchung Cheng | 1fbc340 | 2012-05-02 13:30:02 +0000 | [diff] [blame] | 2625 | tp->prior_ssthresh = 0; |
Yuchung Cheng | 989e04c | 2014-08-22 14:15:22 -0700 | [diff] [blame] | 2626 | tcp_init_undo(tp); |
Yuchung Cheng | 1fbc340 | 2012-05-02 13:30:02 +0000 | [diff] [blame] | 2627 | |
Yuchung Cheng | 291a00d | 2015-07-01 14:11:14 -0700 | [diff] [blame] | 2628 | if (!tcp_in_cwnd_reduction(sk)) { |
Yuchung Cheng | 1fbc340 | 2012-05-02 13:30:02 +0000 | [diff] [blame] | 2629 | if (!ece_ack) |
| 2630 | tp->prior_ssthresh = tcp_current_ssthresh(sk); |
Christoph Paasch | 5ee2c94 | 2014-07-14 16:58:32 +0200 | [diff] [blame] | 2631 | tcp_init_cwnd_reduction(sk); |
Yuchung Cheng | 1fbc340 | 2012-05-02 13:30:02 +0000 | [diff] [blame] | 2632 | } |
Yuchung Cheng | 1fbc340 | 2012-05-02 13:30:02 +0000 | [diff] [blame] | 2633 | tcp_set_ca_state(sk, TCP_CA_Recovery); |
| 2634 | } |
| 2635 | |
Yuchung Cheng | ab42d9e | 2013-03-20 13:32:59 +0000 | [diff] [blame] | 2636 | /* Process an ACK in CA_Loss state. Move to CA_Open if lost data are |
| 2637 | * recovered or spurious. Otherwise retransmits more on partial ACKs. |
| 2638 | */ |
Eric Dumazet | 19119f2 | 2018-11-27 14:42:01 -0800 | [diff] [blame] | 2639 | static void tcp_process_loss(struct sock *sk, int flag, int num_dupack, |
Yuchung Cheng | e662ca4 | 2016-02-02 10:33:04 -0800 | [diff] [blame] | 2640 | int *rexmit) |
Yuchung Cheng | ab42d9e | 2013-03-20 13:32:59 +0000 | [diff] [blame] | 2641 | { |
Yuchung Cheng | ab42d9e | 2013-03-20 13:32:59 +0000 | [diff] [blame] | 2642 | struct tcp_sock *tp = tcp_sk(sk); |
Yuchung Cheng | e33099f | 2013-03-20 13:33:00 +0000 | [diff] [blame] | 2643 | bool recovered = !before(tp->snd_una, tp->high_seq); |
Yuchung Cheng | ab42d9e | 2013-03-20 13:32:59 +0000 | [diff] [blame] | 2644 | |
Yuchung Cheng | da34ac7 | 2015-05-18 12:31:44 -0700 | [diff] [blame] | 2645 | if ((flag & FLAG_SND_UNA_ADVANCED) && |
| 2646 | tcp_try_undo_loss(sk, false)) |
| 2647 | return; |
| 2648 | |
Yuchung Cheng | 89fe18e | 2017-01-12 22:11:37 -0800 | [diff] [blame] | 2649 | if (tp->frto) { /* F-RTO RFC5682 sec 3.1 (sack enhanced version). */ |
Yuchung Cheng | fc68e17 | 2018-02-27 14:15:02 -0800 | [diff] [blame] | 2650 | /* Step 3.b. A timeout is spurious if not all data are |
| 2651 | * lost, i.e., never-retransmitted data are (s)acked. |
| 2652 | */ |
| 2653 | if ((flag & FLAG_ORIG_SACK_ACKED) && |
| 2654 | tcp_try_undo_loss(sk, true)) |
| 2655 | return; |
| 2656 | |
Yuchung Cheng | b7b0ed9 | 2015-05-18 12:31:45 -0700 | [diff] [blame] | 2657 | if (after(tp->snd_nxt, tp->high_seq)) { |
Eric Dumazet | 19119f2 | 2018-11-27 14:42:01 -0800 | [diff] [blame] | 2658 | if (flag & FLAG_DATA_SACKED || num_dupack) |
Yuchung Cheng | b7b0ed9 | 2015-05-18 12:31:45 -0700 | [diff] [blame] | 2659 | tp->frto = 0; /* Step 3.a. loss was real */ |
Yuchung Cheng | e33099f | 2013-03-20 13:33:00 +0000 | [diff] [blame] | 2660 | } else if (flag & FLAG_SND_UNA_ADVANCED && !recovered) { |
| 2661 | tp->high_seq = tp->snd_nxt; |
Yuchung Cheng | e662ca4 | 2016-02-02 10:33:04 -0800 | [diff] [blame] | 2662 | /* Step 2.b. Try send new data (but deferred until cwnd |
| 2663 | * is updated in tcp_ack()). Otherwise fall back to |
| 2664 | * the conventional recovery. |
| 2665 | */ |
Eric Dumazet | 75c119a | 2017-10-05 22:21:27 -0700 | [diff] [blame] | 2666 | if (!tcp_write_queue_empty(sk) && |
Yuchung Cheng | e662ca4 | 2016-02-02 10:33:04 -0800 | [diff] [blame] | 2667 | after(tcp_wnd_end(tp), tp->snd_nxt)) { |
| 2668 | *rexmit = REXMIT_NEW; |
| 2669 | return; |
| 2670 | } |
Yuchung Cheng | e33099f | 2013-03-20 13:33:00 +0000 | [diff] [blame] | 2671 | tp->frto = 0; |
| 2672 | } |
| 2673 | } |
| 2674 | |
| 2675 | if (recovered) { |
| 2676 | /* F-RTO RFC5682 sec 3.1 step 2.a and 1st part of step 3.a */ |
Yuchung Cheng | ab42d9e | 2013-03-20 13:32:59 +0000 | [diff] [blame] | 2677 | tcp_try_undo_recovery(sk); |
| 2678 | return; |
| 2679 | } |
Yuchung Cheng | e33099f | 2013-03-20 13:33:00 +0000 | [diff] [blame] | 2680 | if (tcp_is_reno(tp)) { |
| 2681 | /* A Reno DUPACK means new data in F-RTO step 2.b above are |
| 2682 | * delivered. Lower inflight to clock out (re)tranmissions. |
| 2683 | */ |
Eric Dumazet | 19119f2 | 2018-11-27 14:42:01 -0800 | [diff] [blame] | 2684 | if (after(tp->snd_nxt, tp->high_seq) && num_dupack) |
| 2685 | tcp_add_reno_sack(sk, num_dupack); |
Yuchung Cheng | e33099f | 2013-03-20 13:33:00 +0000 | [diff] [blame] | 2686 | else if (flag & FLAG_SND_UNA_ADVANCED) |
| 2687 | tcp_reset_reno_sack(tp); |
| 2688 | } |
Yuchung Cheng | e662ca4 | 2016-02-02 10:33:04 -0800 | [diff] [blame] | 2689 | *rexmit = REXMIT_LOST; |
Yuchung Cheng | ab42d9e | 2013-03-20 13:32:59 +0000 | [diff] [blame] | 2690 | } |
| 2691 | |
Yuchung Cheng | 6a63df4 | 2013-05-29 14:20:12 +0000 | [diff] [blame] | 2692 | /* Undo during fast recovery after partial ACK. */ |
Yuchung Cheng | 737ff31 | 2017-11-08 13:01:27 -0800 | [diff] [blame] | 2693 | static bool tcp_try_undo_partial(struct sock *sk, u32 prior_snd_una) |
Yuchung Cheng | 6a63df4 | 2013-05-29 14:20:12 +0000 | [diff] [blame] | 2694 | { |
| 2695 | struct tcp_sock *tp = tcp_sk(sk); |
Yuchung Cheng | 6a63df4 | 2013-05-29 14:20:12 +0000 | [diff] [blame] | 2696 | |
Yuchung Cheng | 7026b91 | 2013-05-29 14:20:13 +0000 | [diff] [blame] | 2697 | if (tp->undo_marker && tcp_packet_delayed(tp)) { |
Yuchung Cheng | 6a63df4 | 2013-05-29 14:20:12 +0000 | [diff] [blame] | 2698 | /* Plain luck! Hole if filled with delayed |
Yuchung Cheng | 737ff31 | 2017-11-08 13:01:27 -0800 | [diff] [blame] | 2699 | * packet, rather than with a retransmit. Check reordering. |
Yuchung Cheng | 6a63df4 | 2013-05-29 14:20:12 +0000 | [diff] [blame] | 2700 | */ |
Yuchung Cheng | 737ff31 | 2017-11-08 13:01:27 -0800 | [diff] [blame] | 2701 | tcp_check_sack_reordering(sk, prior_snd_una, 1); |
Yuchung Cheng | 7026b91 | 2013-05-29 14:20:13 +0000 | [diff] [blame] | 2702 | |
| 2703 | /* We are getting evidence that the reordering degree is higher |
| 2704 | * than we realized. If there are no retransmits out then we |
| 2705 | * can undo. Otherwise we clock out new packets but do not |
| 2706 | * mark more packets lost or retransmit more. |
| 2707 | */ |
Yuchung Cheng | 31ba0c1 | 2016-02-02 10:33:05 -0800 | [diff] [blame] | 2708 | if (tp->retrans_out) |
Yuchung Cheng | 7026b91 | 2013-05-29 14:20:13 +0000 | [diff] [blame] | 2709 | return true; |
Yuchung Cheng | 7026b91 | 2013-05-29 14:20:13 +0000 | [diff] [blame] | 2710 | |
Yuchung Cheng | 6a63df4 | 2013-05-29 14:20:12 +0000 | [diff] [blame] | 2711 | if (!tcp_any_retrans_done(sk)) |
| 2712 | tp->retrans_stamp = 0; |
| 2713 | |
Yuchung Cheng | 7026b91 | 2013-05-29 14:20:13 +0000 | [diff] [blame] | 2714 | DBGUNDO(sk, "partial recovery"); |
| 2715 | tcp_undo_cwnd_reduction(sk, true); |
Eric Dumazet | c10d931 | 2016-04-29 14:16:47 -0700 | [diff] [blame] | 2716 | NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPPARTIALUNDO); |
Yuchung Cheng | 7026b91 | 2013-05-29 14:20:13 +0000 | [diff] [blame] | 2717 | tcp_try_keep_open(sk); |
| 2718 | return true; |
Yuchung Cheng | 6a63df4 | 2013-05-29 14:20:12 +0000 | [diff] [blame] | 2719 | } |
Yuchung Cheng | 7026b91 | 2013-05-29 14:20:13 +0000 | [diff] [blame] | 2720 | return false; |
Yuchung Cheng | 6a63df4 | 2013-05-29 14:20:12 +0000 | [diff] [blame] | 2721 | } |
| 2722 | |
Yuchung Cheng | 6ac06ec | 2018-05-16 16:40:12 -0700 | [diff] [blame] | 2723 | static void tcp_identify_packet_loss(struct sock *sk, int *ack_flag) |
Yuchung Cheng | 98e36d4 | 2017-01-12 22:11:35 -0800 | [diff] [blame] | 2724 | { |
| 2725 | struct tcp_sock *tp = tcp_sk(sk); |
| 2726 | |
Yuchung Cheng | 6ac06ec | 2018-05-16 16:40:12 -0700 | [diff] [blame] | 2727 | if (tcp_rtx_queue_empty(sk)) |
| 2728 | return; |
| 2729 | |
| 2730 | if (unlikely(tcp_is_reno(tp))) { |
| 2731 | tcp_newreno_mark_lost(sk, *ack_flag & FLAG_SND_UNA_ADVANCED); |
| 2732 | } else if (tcp_is_rack(sk)) { |
Yuchung Cheng | 98e36d4 | 2017-01-12 22:11:35 -0800 | [diff] [blame] | 2733 | u32 prior_retrans = tp->retrans_out; |
| 2734 | |
Eric Dumazet | 128eda8 | 2017-04-25 10:15:34 -0700 | [diff] [blame] | 2735 | tcp_rack_mark_lost(sk); |
Yuchung Cheng | 98e36d4 | 2017-01-12 22:11:35 -0800 | [diff] [blame] | 2736 | if (prior_retrans > tp->retrans_out) |
| 2737 | *ack_flag |= FLAG_LOST_RETRANS; |
| 2738 | } |
| 2739 | } |
| 2740 | |
Yuchung Cheng | 737ff31 | 2017-11-08 13:01:27 -0800 | [diff] [blame] | 2741 | static bool tcp_force_fast_retransmit(struct sock *sk) |
| 2742 | { |
| 2743 | struct tcp_sock *tp = tcp_sk(sk); |
| 2744 | |
| 2745 | return after(tcp_highest_sack_seq(tp), |
| 2746 | tp->snd_una + tp->reordering * tp->mss_cache); |
| 2747 | } |
| 2748 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2749 | /* Process an event, which can update packets-in-flight not trivially. |
| 2750 | * Main goal of this function is to calculate new estimate for left_out, |
| 2751 | * taking into account both packets sitting in receiver's buffer and |
| 2752 | * packets lost by network. |
| 2753 | * |
Yuchung Cheng | 31ba0c1 | 2016-02-02 10:33:05 -0800 | [diff] [blame] | 2754 | * Besides that it updates the congestion state when packet loss or ECN |
| 2755 | * is detected. But it does not reduce the cwnd, it is done by the |
| 2756 | * congestion control later. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2757 | * |
| 2758 | * It does _not_ decide what to send, it is made in function |
| 2759 | * tcp_xmit_retransmit_queue(). |
| 2760 | */ |
Yuchung Cheng | 737ff31 | 2017-11-08 13:01:27 -0800 | [diff] [blame] | 2761 | static void tcp_fastretrans_alert(struct sock *sk, const u32 prior_snd_una, |
Eric Dumazet | 19119f2 | 2018-11-27 14:42:01 -0800 | [diff] [blame] | 2762 | int num_dupack, int *ack_flag, int *rexmit) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2763 | { |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 2764 | struct inet_connection_sock *icsk = inet_csk(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2765 | struct tcp_sock *tp = tcp_sk(sk); |
Yuchung Cheng | 31ba0c1 | 2016-02-02 10:33:05 -0800 | [diff] [blame] | 2766 | int fast_rexmit = 0, flag = *ack_flag; |
Eric Dumazet | 19119f2 | 2018-11-27 14:42:01 -0800 | [diff] [blame] | 2767 | bool do_lost = num_dupack || ((flag & FLAG_DATA_SACKED) && |
| 2768 | tcp_force_fast_retransmit(sk)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2769 | |
Eric Dumazet | 8ba6dda | 2017-10-05 22:21:25 -0700 | [diff] [blame] | 2770 | if (!tp->packets_out && tp->sacked_out) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2771 | tp->sacked_out = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2772 | |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 2773 | /* Now state machine starts. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2774 | * A. ECE, hence prohibit cwnd undoing, the reduction is required. */ |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 2775 | if (flag & FLAG_ECE) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2776 | tp->prior_ssthresh = 0; |
| 2777 | |
| 2778 | /* B. In all the states check for reneging SACKs. */ |
Ilpo Järvinen | cadbd03 | 2007-12-31 04:49:21 -0800 | [diff] [blame] | 2779 | if (tcp_check_sack_reneging(sk, flag)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2780 | return; |
| 2781 | |
Yuchung Cheng | 974c123 | 2012-01-19 14:42:21 +0000 | [diff] [blame] | 2782 | /* C. Check consistency of the current state. */ |
Ilpo Järvinen | 005903b | 2007-08-09 14:44:16 +0300 | [diff] [blame] | 2783 | tcp_verify_left_out(tp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2784 | |
Yuchung Cheng | 974c123 | 2012-01-19 14:42:21 +0000 | [diff] [blame] | 2785 | /* D. Check state exit conditions. State can be terminated |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2786 | * when high_seq is ACKed. */ |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 2787 | if (icsk->icsk_ca_state == TCP_CA_Open) { |
Ilpo Järvinen | 547b792 | 2008-07-25 21:43:18 -0700 | [diff] [blame] | 2788 | WARN_ON(tp->retrans_out != 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2789 | tp->retrans_stamp = 0; |
| 2790 | } else if (!before(tp->snd_una, tp->high_seq)) { |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 2791 | switch (icsk->icsk_ca_state) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2792 | case TCP_CA_CWR: |
| 2793 | /* CWR is to be held something *above* high_seq |
| 2794 | * is ACKed for CWR bit to reach receiver. */ |
| 2795 | if (tp->snd_una != tp->high_seq) { |
Yuchung Cheng | 684bad1 | 2012-09-02 17:38:04 +0000 | [diff] [blame] | 2796 | tcp_end_cwnd_reduction(sk); |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 2797 | tcp_set_ca_state(sk, TCP_CA_Open); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2798 | } |
| 2799 | break; |
| 2800 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2801 | case TCP_CA_Recovery: |
Ilpo Järvinen | e60402d | 2007-08-09 15:14:46 +0300 | [diff] [blame] | 2802 | if (tcp_is_reno(tp)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2803 | tcp_reset_reno_sack(tp); |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 2804 | if (tcp_try_undo_recovery(sk)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2805 | return; |
Yuchung Cheng | 684bad1 | 2012-09-02 17:38:04 +0000 | [diff] [blame] | 2806 | tcp_end_cwnd_reduction(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2807 | break; |
| 2808 | } |
| 2809 | } |
| 2810 | |
Yuchung Cheng | 974c123 | 2012-01-19 14:42:21 +0000 | [diff] [blame] | 2811 | /* E. Process state. */ |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 2812 | switch (icsk->icsk_ca_state) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2813 | case TCP_CA_Recovery: |
Ilpo Järvinen | 2e60529 | 2007-08-02 19:46:58 -0700 | [diff] [blame] | 2814 | if (!(flag & FLAG_SND_UNA_ADVANCED)) { |
Eric Dumazet | 19119f2 | 2018-11-27 14:42:01 -0800 | [diff] [blame] | 2815 | if (tcp_is_reno(tp)) |
| 2816 | tcp_add_reno_sack(sk, num_dupack); |
Yuchung Cheng | 7026b91 | 2013-05-29 14:20:13 +0000 | [diff] [blame] | 2817 | } else { |
Yuchung Cheng | 737ff31 | 2017-11-08 13:01:27 -0800 | [diff] [blame] | 2818 | if (tcp_try_undo_partial(sk, prior_snd_una)) |
Yuchung Cheng | 7026b91 | 2013-05-29 14:20:13 +0000 | [diff] [blame] | 2819 | return; |
| 2820 | /* Partial ACK arrived. Force fast retransmit. */ |
| 2821 | do_lost = tcp_is_reno(tp) || |
Yuchung Cheng | 737ff31 | 2017-11-08 13:01:27 -0800 | [diff] [blame] | 2822 | tcp_force_fast_retransmit(sk); |
Yuchung Cheng | 7026b91 | 2013-05-29 14:20:13 +0000 | [diff] [blame] | 2823 | } |
Yuchung Cheng | c7d9d6a | 2013-05-29 14:20:14 +0000 | [diff] [blame] | 2824 | if (tcp_try_undo_dsack(sk)) { |
| 2825 | tcp_try_keep_open(sk); |
| 2826 | return; |
| 2827 | } |
Yuchung Cheng | 6ac06ec | 2018-05-16 16:40:12 -0700 | [diff] [blame] | 2828 | tcp_identify_packet_loss(sk, ack_flag); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2829 | break; |
| 2830 | case TCP_CA_Loss: |
Eric Dumazet | 19119f2 | 2018-11-27 14:42:01 -0800 | [diff] [blame] | 2831 | tcp_process_loss(sk, flag, num_dupack, rexmit); |
Yuchung Cheng | 6ac06ec | 2018-05-16 16:40:12 -0700 | [diff] [blame] | 2832 | tcp_identify_packet_loss(sk, ack_flag); |
Yuchung Cheng | 98e36d4 | 2017-01-12 22:11:35 -0800 | [diff] [blame] | 2833 | if (!(icsk->icsk_ca_state == TCP_CA_Open || |
| 2834 | (*ack_flag & FLAG_LOST_RETRANS))) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2835 | return; |
Yuchung Cheng | 291a00d | 2015-07-01 14:11:14 -0700 | [diff] [blame] | 2836 | /* Change state if cwnd is undone or retransmits are lost */ |
Gustavo A. R. Silva | fcfd6df | 2017-10-16 15:48:55 -0500 | [diff] [blame] | 2837 | /* fall through */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2838 | default: |
Ilpo Järvinen | e60402d | 2007-08-09 15:14:46 +0300 | [diff] [blame] | 2839 | if (tcp_is_reno(tp)) { |
Ilpo Järvinen | 2e60529 | 2007-08-02 19:46:58 -0700 | [diff] [blame] | 2840 | if (flag & FLAG_SND_UNA_ADVANCED) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2841 | tcp_reset_reno_sack(tp); |
Eric Dumazet | 19119f2 | 2018-11-27 14:42:01 -0800 | [diff] [blame] | 2842 | tcp_add_reno_sack(sk, num_dupack); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2843 | } |
| 2844 | |
Neal Cardwell | f698204 | 2011-11-16 08:58:04 +0000 | [diff] [blame] | 2845 | if (icsk->icsk_ca_state <= TCP_CA_Disorder) |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 2846 | tcp_try_undo_dsack(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2847 | |
Yuchung Cheng | 6ac06ec | 2018-05-16 16:40:12 -0700 | [diff] [blame] | 2848 | tcp_identify_packet_loss(sk, ack_flag); |
Yuchung Cheng | 750ea2b | 2012-05-02 13:30:04 +0000 | [diff] [blame] | 2849 | if (!tcp_time_to_recover(sk, flag)) { |
Yuchung Cheng | 31ba0c1 | 2016-02-02 10:33:05 -0800 | [diff] [blame] | 2850 | tcp_try_to_open(sk, flag); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2851 | return; |
| 2852 | } |
| 2853 | |
John Heffner | 5d424d5 | 2006-03-20 17:53:41 -0800 | [diff] [blame] | 2854 | /* MTU probe failure: don't reduce cwnd */ |
| 2855 | if (icsk->icsk_ca_state < TCP_CA_CWR && |
| 2856 | icsk->icsk_mtup.probe_size && |
John Heffner | 0e7b1368 | 2006-03-20 21:32:58 -0800 | [diff] [blame] | 2857 | tp->snd_una == tp->mtu_probe.probe_seq_start) { |
John Heffner | 5d424d5 | 2006-03-20 17:53:41 -0800 | [diff] [blame] | 2858 | tcp_mtup_probe_failed(sk); |
| 2859 | /* Restores the reduction we did in tcp_mtup_probe() */ |
| 2860 | tp->snd_cwnd++; |
| 2861 | tcp_simple_retransmit(sk); |
| 2862 | return; |
| 2863 | } |
| 2864 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2865 | /* Otherwise enter Recovery state */ |
Yuchung Cheng | 1fbc340 | 2012-05-02 13:30:02 +0000 | [diff] [blame] | 2866 | tcp_enter_recovery(sk, (flag & FLAG_ECE)); |
Ilpo Järvinen | 85cc391 | 2007-11-15 19:39:31 -0800 | [diff] [blame] | 2867 | fast_rexmit = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2868 | } |
| 2869 | |
Yuchung Cheng | b38a51f | 2018-05-16 16:40:11 -0700 | [diff] [blame] | 2870 | if (!tcp_is_rack(sk) && do_lost) |
Ilpo Järvinen | 85cc391 | 2007-11-15 19:39:31 -0800 | [diff] [blame] | 2871 | tcp_update_scoreboard(sk, fast_rexmit); |
Yuchung Cheng | e662ca4 | 2016-02-02 10:33:04 -0800 | [diff] [blame] | 2872 | *rexmit = REXMIT_LOST; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2873 | } |
| 2874 | |
Yuchung Cheng | eb36be0 | 2018-01-17 12:11:00 -0800 | [diff] [blame] | 2875 | static void tcp_update_rtt_min(struct sock *sk, u32 rtt_us, const int flag) |
Yuchung Cheng | f672258 | 2015-10-16 21:57:42 -0700 | [diff] [blame] | 2876 | { |
Eric Dumazet | bd23970 | 2017-10-27 07:47:28 -0700 | [diff] [blame] | 2877 | u32 wlen = sock_net(sk)->ipv4.sysctl_tcp_min_rtt_wlen * HZ; |
Neal Cardwell | 6403389 | 2016-09-19 23:39:10 -0400 | [diff] [blame] | 2878 | struct tcp_sock *tp = tcp_sk(sk); |
Yuchung Cheng | f672258 | 2015-10-16 21:57:42 -0700 | [diff] [blame] | 2879 | |
Yuchung Cheng | eb36be0 | 2018-01-17 12:11:00 -0800 | [diff] [blame] | 2880 | if ((flag & FLAG_ACK_MAYBE_DELAYED) && rtt_us > tcp_min_rtt(tp)) { |
| 2881 | /* If the remote keeps returning delayed ACKs, eventually |
| 2882 | * the min filter would pick it up and overestimate the |
| 2883 | * prop. delay when it expires. Skip suspected delayed ACKs. |
| 2884 | */ |
| 2885 | return; |
| 2886 | } |
Eric Dumazet | ac9517f | 2017-05-16 14:00:13 -0700 | [diff] [blame] | 2887 | minmax_running_min(&tp->rtt_min, wlen, tcp_jiffies32, |
Neal Cardwell | 6403389 | 2016-09-19 23:39:10 -0400 | [diff] [blame] | 2888 | rtt_us ? : jiffies_to_usecs(1)); |
Yuchung Cheng | f672258 | 2015-10-16 21:57:42 -0700 | [diff] [blame] | 2889 | } |
| 2890 | |
Yuchung Cheng | 775e68a | 2017-05-31 11:30:53 -0700 | [diff] [blame] | 2891 | static bool tcp_ack_update_rtt(struct sock *sk, const int flag, |
| 2892 | long seq_rtt_us, long sack_rtt_us, |
| 2893 | long ca_rtt_us, struct rate_sample *rs) |
Ilpo Järvinen | 41834b7 | 2008-12-05 22:43:26 -0800 | [diff] [blame] | 2894 | { |
Yuchung Cheng | 5b08e47 | 2013-07-22 16:20:46 -0700 | [diff] [blame] | 2895 | const struct tcp_sock *tp = tcp_sk(sk); |
Ilpo Järvinen | 41834b7 | 2008-12-05 22:43:26 -0800 | [diff] [blame] | 2896 | |
Yuchung Cheng | 5b08e47 | 2013-07-22 16:20:46 -0700 | [diff] [blame] | 2897 | /* Prefer RTT measured from ACK's timing to TS-ECR. This is because |
| 2898 | * broken middle-boxes or peers may corrupt TS-ECR fields. But |
| 2899 | * Karn's algorithm forbids taking RTT if some retransmitted data |
| 2900 | * is acked (RFC6298). |
| 2901 | */ |
Eric Dumazet | 740b0f1 | 2014-02-26 14:02:48 -0800 | [diff] [blame] | 2902 | if (seq_rtt_us < 0) |
| 2903 | seq_rtt_us = sack_rtt_us; |
Yuchung Cheng | ed08495 | 2013-07-22 16:20:48 -0700 | [diff] [blame] | 2904 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2905 | /* RTTM Rule: A TSecr value received in a segment is used to |
| 2906 | * update the averaged RTT measurement only if the segment |
| 2907 | * acknowledges some new data, i.e., only if it advances the |
| 2908 | * left edge of the send window. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2909 | * See draft-ietf-tcplw-high-performance-00, section 3.3. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2910 | */ |
Eric Dumazet | 740b0f1 | 2014-02-26 14:02:48 -0800 | [diff] [blame] | 2911 | if (seq_rtt_us < 0 && tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr && |
Eric Dumazet | 9a568de | 2017-05-16 14:00:14 -0700 | [diff] [blame] | 2912 | flag & FLAG_ACKED) { |
| 2913 | u32 delta = tcp_time_stamp(tp) - tp->rx_opt.rcv_tsecr; |
Eric Dumazet | 9a568de | 2017-05-16 14:00:14 -0700 | [diff] [blame] | 2914 | |
Eric Dumazet | 9efdda4 | 2018-11-24 09:12:24 -0800 | [diff] [blame] | 2915 | if (likely(delta < INT_MAX / (USEC_PER_SEC / TCP_TS_HZ))) { |
| 2916 | seq_rtt_us = delta * (USEC_PER_SEC / TCP_TS_HZ); |
| 2917 | ca_rtt_us = seq_rtt_us; |
| 2918 | } |
Eric Dumazet | 9a568de | 2017-05-16 14:00:14 -0700 | [diff] [blame] | 2919 | } |
Yuchung Cheng | 775e68a | 2017-05-31 11:30:53 -0700 | [diff] [blame] | 2920 | rs->rtt_us = ca_rtt_us; /* RTT of last (S)ACKed packet (or -1) */ |
Eric Dumazet | 740b0f1 | 2014-02-26 14:02:48 -0800 | [diff] [blame] | 2921 | if (seq_rtt_us < 0) |
Yuchung Cheng | ed08495 | 2013-07-22 16:20:48 -0700 | [diff] [blame] | 2922 | return false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2923 | |
Yuchung Cheng | f672258 | 2015-10-16 21:57:42 -0700 | [diff] [blame] | 2924 | /* ca_rtt_us >= 0 is counting on the invariant that ca_rtt_us is |
| 2925 | * always taken together with ACK, SACK, or TS-opts. Any negative |
| 2926 | * values will be skipped with the seq_rtt_us < 0 check above. |
| 2927 | */ |
Yuchung Cheng | eb36be0 | 2018-01-17 12:11:00 -0800 | [diff] [blame] | 2928 | tcp_update_rtt_min(sk, ca_rtt_us, flag); |
Eric Dumazet | 740b0f1 | 2014-02-26 14:02:48 -0800 | [diff] [blame] | 2929 | tcp_rtt_estimator(sk, seq_rtt_us); |
Yuchung Cheng | 5b08e47 | 2013-07-22 16:20:46 -0700 | [diff] [blame] | 2930 | tcp_set_rto(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2931 | |
Yuchung Cheng | 5b08e47 | 2013-07-22 16:20:46 -0700 | [diff] [blame] | 2932 | /* RFC6298: only reset backoff on valid RTT measurement. */ |
| 2933 | inet_csk(sk)->icsk_backoff = 0; |
Yuchung Cheng | ed08495 | 2013-07-22 16:20:48 -0700 | [diff] [blame] | 2934 | return true; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2935 | } |
| 2936 | |
Yuchung Cheng | 375fe02 | 2013-07-22 16:20:45 -0700 | [diff] [blame] | 2937 | /* Compute time elapsed between (last) SYNACK and the ACK completing 3WHS. */ |
Yuchung Cheng | 0f1c28a | 2015-09-18 11:36:14 -0700 | [diff] [blame] | 2938 | void tcp_synack_rtt_meas(struct sock *sk, struct request_sock *req) |
Yuchung Cheng | 375fe02 | 2013-07-22 16:20:45 -0700 | [diff] [blame] | 2939 | { |
Yuchung Cheng | 775e68a | 2017-05-31 11:30:53 -0700 | [diff] [blame] | 2940 | struct rate_sample rs; |
Yuchung Cheng | 0f1c28a | 2015-09-18 11:36:14 -0700 | [diff] [blame] | 2941 | long rtt_us = -1L; |
Yuchung Cheng | 375fe02 | 2013-07-22 16:20:45 -0700 | [diff] [blame] | 2942 | |
Eric Dumazet | 9a568de | 2017-05-16 14:00:14 -0700 | [diff] [blame] | 2943 | if (req && !req->num_retrans && tcp_rsk(req)->snt_synack) |
| 2944 | rtt_us = tcp_stamp_us_delta(tcp_clock_us(), tcp_rsk(req)->snt_synack); |
Yuchung Cheng | 0f1c28a | 2015-09-18 11:36:14 -0700 | [diff] [blame] | 2945 | |
Yuchung Cheng | 775e68a | 2017-05-31 11:30:53 -0700 | [diff] [blame] | 2946 | tcp_ack_update_rtt(sk, FLAG_SYN_ACKED, rtt_us, -1L, rtt_us, &rs); |
Yuchung Cheng | 375fe02 | 2013-07-22 16:20:45 -0700 | [diff] [blame] | 2947 | } |
| 2948 | |
Yuchung Cheng | 0f1c28a | 2015-09-18 11:36:14 -0700 | [diff] [blame] | 2949 | |
Eric Dumazet | 2490155 | 2014-05-02 21:18:05 -0700 | [diff] [blame] | 2950 | static void tcp_cong_avoid(struct sock *sk, u32 ack, u32 acked) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2951 | { |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 2952 | const struct inet_connection_sock *icsk = inet_csk(sk); |
Eric Dumazet | 2490155 | 2014-05-02 21:18:05 -0700 | [diff] [blame] | 2953 | |
| 2954 | icsk->icsk_ca_ops->cong_avoid(sk, ack, acked); |
Eric Dumazet | c2203cf | 2017-05-16 14:00:04 -0700 | [diff] [blame] | 2955 | tcp_sk(sk)->snd_cwnd_stamp = tcp_jiffies32; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2956 | } |
| 2957 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2958 | /* Restart timer after forward progress on connection. |
| 2959 | * RFC2988 recommends to restart timer to now+rto. |
| 2960 | */ |
Yuchung Cheng | 750ea2b | 2012-05-02 13:30:04 +0000 | [diff] [blame] | 2961 | void tcp_rearm_rto(struct sock *sk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2962 | { |
Nandita Dukkipati | 6ba8a3b | 2013-03-11 10:00:43 +0000 | [diff] [blame] | 2963 | const struct inet_connection_sock *icsk = inet_csk(sk); |
Yuchung Cheng | 750ea2b | 2012-05-02 13:30:04 +0000 | [diff] [blame] | 2964 | struct tcp_sock *tp = tcp_sk(sk); |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 2965 | |
Jerry Chu | 168a8f5 | 2012-08-31 12:29:13 +0000 | [diff] [blame] | 2966 | /* If the retrans timer is currently being used by Fast Open |
| 2967 | * for SYN-ACK retrans purpose, stay put. |
| 2968 | */ |
| 2969 | if (tp->fastopen_rsk) |
| 2970 | return; |
| 2971 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2972 | if (!tp->packets_out) { |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 2973 | inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2974 | } else { |
Yuchung Cheng | 750ea2b | 2012-05-02 13:30:04 +0000 | [diff] [blame] | 2975 | u32 rto = inet_csk(sk)->icsk_rto; |
| 2976 | /* Offset the time elapsed after installing regular RTO */ |
Yuchung Cheng | bec41a1 | 2017-01-12 22:11:39 -0800 | [diff] [blame] | 2977 | if (icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT || |
Nandita Dukkipati | 6ba8a3b | 2013-03-11 10:00:43 +0000 | [diff] [blame] | 2978 | icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) { |
Neal Cardwell | e1a10ef | 2017-08-03 09:19:52 -0400 | [diff] [blame] | 2979 | s64 delta_us = tcp_rto_delta_us(sk); |
Eric Dumazet | b17b8a2 | 2017-05-18 09:15:58 -0700 | [diff] [blame] | 2980 | /* delta_us may not be positive if the socket is locked |
Nandita Dukkipati | 6ba8a3b | 2013-03-11 10:00:43 +0000 | [diff] [blame] | 2981 | * when the retrans timer fires and is rescheduled. |
Yuchung Cheng | 750ea2b | 2012-05-02 13:30:04 +0000 | [diff] [blame] | 2982 | */ |
Neal Cardwell | cdbeb63 | 2017-08-16 17:53:36 -0400 | [diff] [blame] | 2983 | rto = usecs_to_jiffies(max_t(int, delta_us, 1)); |
Yuchung Cheng | 750ea2b | 2012-05-02 13:30:04 +0000 | [diff] [blame] | 2984 | } |
Eric Dumazet | 3f80e08 | 2018-10-23 11:54:16 -0700 | [diff] [blame] | 2985 | tcp_reset_xmit_timer(sk, ICSK_TIME_RETRANS, rto, |
| 2986 | TCP_RTO_MAX, tcp_rtx_queue_head(sk)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2987 | } |
Yuchung Cheng | 750ea2b | 2012-05-02 13:30:04 +0000 | [diff] [blame] | 2988 | } |
| 2989 | |
Neal Cardwell | df92c83 | 2017-08-03 09:19:54 -0400 | [diff] [blame] | 2990 | /* Try to schedule a loss probe; if that doesn't work, then schedule an RTO. */ |
| 2991 | static void tcp_set_xmit_timer(struct sock *sk) |
| 2992 | { |
Neal Cardwell | ed66dfa | 2017-11-17 21:06:14 -0500 | [diff] [blame] | 2993 | if (!tcp_schedule_loss_probe(sk, true)) |
Neal Cardwell | df92c83 | 2017-08-03 09:19:54 -0400 | [diff] [blame] | 2994 | tcp_rearm_rto(sk); |
| 2995 | } |
| 2996 | |
Ilpo Järvinen | 7c46a03 | 2007-09-20 11:33:43 -0700 | [diff] [blame] | 2997 | /* If we get here, the whole TSO packet has not been acked. */ |
Ilpo Järvinen | 13fcf85 | 2007-10-09 01:28:45 -0700 | [diff] [blame] | 2998 | static u32 tcp_tso_acked(struct sock *sk, struct sk_buff *skb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2999 | { |
| 3000 | struct tcp_sock *tp = tcp_sk(sk); |
Ilpo Järvinen | 7c46a03 | 2007-09-20 11:33:43 -0700 | [diff] [blame] | 3001 | u32 packets_acked; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3002 | |
Ilpo Järvinen | 7c46a03 | 2007-09-20 11:33:43 -0700 | [diff] [blame] | 3003 | BUG_ON(!after(TCP_SKB_CB(skb)->end_seq, tp->snd_una)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3004 | |
| 3005 | packets_acked = tcp_skb_pcount(skb); |
Ilpo Järvinen | 7c46a03 | 2007-09-20 11:33:43 -0700 | [diff] [blame] | 3006 | if (tcp_trim_head(sk, skb, tp->snd_una - TCP_SKB_CB(skb)->seq)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3007 | return 0; |
| 3008 | packets_acked -= tcp_skb_pcount(skb); |
| 3009 | |
| 3010 | if (packets_acked) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3011 | BUG_ON(tcp_skb_pcount(skb) == 0); |
Ilpo Järvinen | 7c46a03 | 2007-09-20 11:33:43 -0700 | [diff] [blame] | 3012 | BUG_ON(!before(TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3013 | } |
| 3014 | |
Ilpo Järvinen | 13fcf85 | 2007-10-09 01:28:45 -0700 | [diff] [blame] | 3015 | return packets_acked; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3016 | } |
| 3017 | |
Eric Dumazet | ad971f6 | 2014-10-11 15:17:29 -0700 | [diff] [blame] | 3018 | static void tcp_ack_tstamp(struct sock *sk, struct sk_buff *skb, |
| 3019 | u32 prior_snd_una) |
| 3020 | { |
| 3021 | const struct skb_shared_info *shinfo; |
| 3022 | |
| 3023 | /* Avoid cache line misses to get skb_shinfo() and shinfo->tx_flags */ |
Soheil Hassas Yeganeh | 6b08492 | 2016-04-02 23:08:08 -0400 | [diff] [blame] | 3024 | if (likely(!TCP_SKB_CB(skb)->txstamp_ack)) |
Eric Dumazet | ad971f6 | 2014-10-11 15:17:29 -0700 | [diff] [blame] | 3025 | return; |
| 3026 | |
| 3027 | shinfo = skb_shinfo(skb); |
Soheil Hassas Yeganeh | 0a2cf20 | 2016-04-27 23:39:01 -0400 | [diff] [blame] | 3028 | if (!before(shinfo->tskey, prior_snd_una) && |
Eric Dumazet | e208007 | 2017-10-04 12:59:58 -0700 | [diff] [blame] | 3029 | before(shinfo->tskey, tcp_sk(sk)->snd_una)) { |
| 3030 | tcp_skb_tsorted_save(skb) { |
| 3031 | __skb_tstamp_tx(skb, NULL, sk, SCM_TSTAMP_ACK); |
| 3032 | } tcp_skb_tsorted_restore(skb); |
| 3033 | } |
Eric Dumazet | ad971f6 | 2014-10-11 15:17:29 -0700 | [diff] [blame] | 3034 | } |
| 3035 | |
Ilpo Järvinen | 7c46a03 | 2007-09-20 11:33:43 -0700 | [diff] [blame] | 3036 | /* Remove acknowledged frames from the retransmission queue. If our packet |
| 3037 | * is before the ack sequence we can discard it as it's confirmed to have |
| 3038 | * arrived at the other end. |
| 3039 | */ |
Yuchung Cheng | 737ff31 | 2017-11-08 13:01:27 -0800 | [diff] [blame] | 3040 | static int tcp_clean_rtx_queue(struct sock *sk, u32 prior_fack, |
| 3041 | u32 prior_snd_una, |
Yuchung Cheng | deed7be | 2017-01-12 22:11:32 -0800 | [diff] [blame] | 3042 | struct tcp_sacktag_state *sack) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3043 | { |
Stephen Hemminger | 2d2abba | 2005-11-10 16:56:12 -0800 | [diff] [blame] | 3044 | const struct inet_connection_sock *icsk = inet_csk(sk); |
Eric Dumazet | 9a568de | 2017-05-16 14:00:14 -0700 | [diff] [blame] | 3045 | u64 first_ackt, last_ackt; |
Eric Dumazet | 740b0f1 | 2014-02-26 14:02:48 -0800 | [diff] [blame] | 3046 | struct tcp_sock *tp = tcp_sk(sk); |
Ilpo Järvinen | 90638a0 | 2008-09-20 21:25:52 -0700 | [diff] [blame] | 3047 | u32 prior_sacked = tp->sacked_out; |
Yuchung Cheng | 737ff31 | 2017-11-08 13:01:27 -0800 | [diff] [blame] | 3048 | u32 reord = tp->snd_nxt; /* lowest acked un-retx un-sacked seq */ |
Eric Dumazet | 75c119a | 2017-10-05 22:21:27 -0700 | [diff] [blame] | 3049 | struct sk_buff *skb, *next; |
Eric Dumazet | 740b0f1 | 2014-02-26 14:02:48 -0800 | [diff] [blame] | 3050 | bool fully_acked = true; |
Kenneth Klette Jonassen | 31231a8 | 2015-05-01 01:10:58 +0200 | [diff] [blame] | 3051 | long sack_rtt_us = -1L; |
Eric Dumazet | 740b0f1 | 2014-02-26 14:02:48 -0800 | [diff] [blame] | 3052 | long seq_rtt_us = -1L; |
Kenneth Klette Jonassen | 31231a8 | 2015-05-01 01:10:58 +0200 | [diff] [blame] | 3053 | long ca_rtt_us = -1L; |
Eric Dumazet | 740b0f1 | 2014-02-26 14:02:48 -0800 | [diff] [blame] | 3054 | u32 pkts_acked = 0; |
Lawrence Brakmo | 6f094b9 | 2016-06-08 21:16:44 -0700 | [diff] [blame] | 3055 | u32 last_in_flight = 0; |
Yuchung Cheng | 2f715c1 | 2013-10-24 08:59:27 -0700 | [diff] [blame] | 3056 | bool rtt_update; |
Eric Dumazet | 740b0f1 | 2014-02-26 14:02:48 -0800 | [diff] [blame] | 3057 | int flag = 0; |
| 3058 | |
Eric Dumazet | 9a568de | 2017-05-16 14:00:14 -0700 | [diff] [blame] | 3059 | first_ackt = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3060 | |
Eric Dumazet | 75c119a | 2017-10-05 22:21:27 -0700 | [diff] [blame] | 3061 | for (skb = skb_rb_first(&sk->tcp_rtx_queue); skb; skb = next) { |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 3062 | struct tcp_skb_cb *scb = TCP_SKB_CB(skb); |
Yuchung Cheng | 737ff31 | 2017-11-08 13:01:27 -0800 | [diff] [blame] | 3063 | const u32 start_seq = scb->seq; |
Ilpo Järvinen | 7c46a03 | 2007-09-20 11:33:43 -0700 | [diff] [blame] | 3064 | u8 sacked = scb->sacked; |
Eric Dumazet | 740b0f1 | 2014-02-26 14:02:48 -0800 | [diff] [blame] | 3065 | u32 acked_pcount; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3066 | |
Eric Dumazet | ad971f6 | 2014-10-11 15:17:29 -0700 | [diff] [blame] | 3067 | tcp_ack_tstamp(sk, skb, prior_snd_una); |
Willem de Bruijn | 712a722 | 2014-08-12 14:53:16 -0400 | [diff] [blame] | 3068 | |
Gavin McCullagh | 2072c22 | 2007-12-29 19:11:21 -0800 | [diff] [blame] | 3069 | /* Determine how many packets and what bytes were acked, tso and else */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3070 | if (after(scb->end_seq, tp->snd_una)) { |
Ilpo Järvinen | 13fcf85 | 2007-10-09 01:28:45 -0700 | [diff] [blame] | 3071 | if (tcp_skb_pcount(skb) == 1 || |
| 3072 | !after(tp->snd_una, scb->seq)) |
| 3073 | break; |
| 3074 | |
Ilpo Järvinen | 7201883 | 2007-12-30 04:37:55 -0800 | [diff] [blame] | 3075 | acked_pcount = tcp_tso_acked(sk, skb); |
| 3076 | if (!acked_pcount) |
Ilpo Järvinen | 13fcf85 | 2007-10-09 01:28:45 -0700 | [diff] [blame] | 3077 | break; |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 3078 | fully_acked = false; |
Ilpo Järvinen | 13fcf85 | 2007-10-09 01:28:45 -0700 | [diff] [blame] | 3079 | } else { |
Ilpo Järvinen | 7201883 | 2007-12-30 04:37:55 -0800 | [diff] [blame] | 3080 | acked_pcount = tcp_skb_pcount(skb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3081 | } |
| 3082 | |
Eric Dumazet | ad971f6 | 2014-10-11 15:17:29 -0700 | [diff] [blame] | 3083 | if (unlikely(sacked & TCPCB_RETRANS)) { |
Ilpo Järvinen | 89d478f | 2007-12-30 04:35:27 -0800 | [diff] [blame] | 3084 | if (sacked & TCPCB_SACKED_RETRANS) |
Ilpo Järvinen | 7201883 | 2007-12-30 04:37:55 -0800 | [diff] [blame] | 3085 | tp->retrans_out -= acked_pcount; |
Ilpo Järvinen | 89d478f | 2007-12-30 04:35:27 -0800 | [diff] [blame] | 3086 | flag |= FLAG_RETRANS_DATA_ACKED; |
Kenneth Klette Jonassen | 3d0d26c | 2015-04-11 02:17:49 +0200 | [diff] [blame] | 3087 | } else if (!(sacked & TCPCB_SACKED_ACKED)) { |
Eric Dumazet | 2fd66ff | 2018-09-21 08:51:47 -0700 | [diff] [blame] | 3088 | last_ackt = tcp_skb_timestamp_us(skb); |
Eric Dumazet | 9a568de | 2017-05-16 14:00:14 -0700 | [diff] [blame] | 3089 | WARN_ON_ONCE(last_ackt == 0); |
| 3090 | if (!first_ackt) |
Eric Dumazet | 740b0f1 | 2014-02-26 14:02:48 -0800 | [diff] [blame] | 3091 | first_ackt = last_ackt; |
| 3092 | |
Lawrence Brakmo | 6f094b9 | 2016-06-08 21:16:44 -0700 | [diff] [blame] | 3093 | last_in_flight = TCP_SKB_CB(skb)->tx.in_flight; |
Yuchung Cheng | 737ff31 | 2017-11-08 13:01:27 -0800 | [diff] [blame] | 3094 | if (before(start_seq, reord)) |
| 3095 | reord = start_seq; |
Kenneth Klette Jonassen | 3d0d26c | 2015-04-11 02:17:49 +0200 | [diff] [blame] | 3096 | if (!after(scb->end_seq, tp->high_seq)) |
| 3097 | flag |= FLAG_ORIG_SACK_ACKED; |
Stephen Hemminger | 2d2abba | 2005-11-10 16:56:12 -0800 | [diff] [blame] | 3098 | } |
Ilpo Järvinen | 89d478f | 2007-12-30 04:35:27 -0800 | [diff] [blame] | 3099 | |
Yuchung Cheng | ddf1af6 | 2016-02-02 10:33:06 -0800 | [diff] [blame] | 3100 | if (sacked & TCPCB_SACKED_ACKED) { |
Ilpo Järvinen | 7201883 | 2007-12-30 04:37:55 -0800 | [diff] [blame] | 3101 | tp->sacked_out -= acked_pcount; |
Yuchung Cheng | ddf1af6 | 2016-02-02 10:33:06 -0800 | [diff] [blame] | 3102 | } else if (tcp_is_sack(tp)) { |
| 3103 | tp->delivered += acked_pcount; |
| 3104 | if (!tcp_skb_spurious_retrans(tp, skb)) |
Yuchung Cheng | 1d0833d | 2017-01-12 22:11:34 -0800 | [diff] [blame] | 3105 | tcp_rack_advance(tp, sacked, scb->end_seq, |
Eric Dumazet | 2fd66ff | 2018-09-21 08:51:47 -0700 | [diff] [blame] | 3106 | tcp_skb_timestamp_us(skb)); |
Yuchung Cheng | ddf1af6 | 2016-02-02 10:33:06 -0800 | [diff] [blame] | 3107 | } |
Ilpo Järvinen | 89d478f | 2007-12-30 04:35:27 -0800 | [diff] [blame] | 3108 | if (sacked & TCPCB_LOST) |
Ilpo Järvinen | 7201883 | 2007-12-30 04:37:55 -0800 | [diff] [blame] | 3109 | tp->lost_out -= acked_pcount; |
Ilpo Järvinen | 89d478f | 2007-12-30 04:35:27 -0800 | [diff] [blame] | 3110 | |
Ilpo Järvinen | 7201883 | 2007-12-30 04:37:55 -0800 | [diff] [blame] | 3111 | tp->packets_out -= acked_pcount; |
| 3112 | pkts_acked += acked_pcount; |
Yuchung Cheng | b9f6482 | 2016-09-19 23:39:14 -0400 | [diff] [blame] | 3113 | tcp_rate_skb_delivered(sk, skb, sack->rate); |
Ilpo Järvinen | 13fcf85 | 2007-10-09 01:28:45 -0700 | [diff] [blame] | 3114 | |
Ilpo Järvinen | 009a2e3 | 2007-09-20 11:34:38 -0700 | [diff] [blame] | 3115 | /* Initial outgoing SYN's get put onto the write_queue |
| 3116 | * just like anything else we transmit. It is not |
| 3117 | * true data, and if we misinform our callers that |
| 3118 | * this ACK acks real data, we will erroneously exit |
| 3119 | * connection startup slow start one packet too |
| 3120 | * quickly. This is severely frowned upon behavior. |
| 3121 | */ |
Eric Dumazet | ad971f6 | 2014-10-11 15:17:29 -0700 | [diff] [blame] | 3122 | if (likely(!(scb->tcp_flags & TCPHDR_SYN))) { |
Ilpo Järvinen | 009a2e3 | 2007-09-20 11:34:38 -0700 | [diff] [blame] | 3123 | flag |= FLAG_DATA_ACKED; |
| 3124 | } else { |
| 3125 | flag |= FLAG_SYN_ACKED; |
| 3126 | tp->retrans_stamp = 0; |
| 3127 | } |
| 3128 | |
Ilpo Järvinen | 13fcf85 | 2007-10-09 01:28:45 -0700 | [diff] [blame] | 3129 | if (!fully_acked) |
| 3130 | break; |
| 3131 | |
Eric Dumazet | 75c119a | 2017-10-05 22:21:27 -0700 | [diff] [blame] | 3132 | next = skb_rb_next(skb); |
Eric Dumazet | ad971f6 | 2014-10-11 15:17:29 -0700 | [diff] [blame] | 3133 | if (unlikely(skb == tp->retransmit_skb_hint)) |
Ilpo Järvinen | ef9da47 | 2008-09-20 21:25:15 -0700 | [diff] [blame] | 3134 | tp->retransmit_skb_hint = NULL; |
Eric Dumazet | ad971f6 | 2014-10-11 15:17:29 -0700 | [diff] [blame] | 3135 | if (unlikely(skb == tp->lost_skb_hint)) |
Ilpo Järvinen | 90638a0 | 2008-09-20 21:25:52 -0700 | [diff] [blame] | 3136 | tp->lost_skb_hint = NULL; |
Eric Dumazet | 75c119a | 2017-10-05 22:21:27 -0700 | [diff] [blame] | 3137 | tcp_rtx_queue_unlink_and_free(skb, sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3138 | } |
| 3139 | |
Francis Yan | 0f87230 | 2016-11-27 23:07:14 -0800 | [diff] [blame] | 3140 | if (!skb) |
| 3141 | tcp_chrono_stop(sk, TCP_CHRONO_BUSY); |
| 3142 | |
Ilpo Järvinen | 33f5f57 | 2008-10-07 14:43:06 -0700 | [diff] [blame] | 3143 | if (likely(between(tp->snd_up, prior_snd_una, tp->snd_una))) |
| 3144 | tp->snd_up = tp->snd_una; |
| 3145 | |
Ilpo Järvinen | cadbd03 | 2007-12-31 04:49:21 -0800 | [diff] [blame] | 3146 | if (skb && (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED)) |
| 3147 | flag |= FLAG_SACK_RENEGING; |
| 3148 | |
Eric Dumazet | 9a568de | 2017-05-16 14:00:14 -0700 | [diff] [blame] | 3149 | if (likely(first_ackt) && !(flag & FLAG_RETRANS_DATA_ACKED)) { |
| 3150 | seq_rtt_us = tcp_stamp_us_delta(tp->tcp_mstamp, first_ackt); |
| 3151 | ca_rtt_us = tcp_stamp_us_delta(tp->tcp_mstamp, last_ackt); |
Yuchung Cheng | eb36be0 | 2018-01-17 12:11:00 -0800 | [diff] [blame] | 3152 | |
| 3153 | if (pkts_acked == 1 && last_in_flight < tp->mss_cache && |
| 3154 | last_in_flight && !prior_sacked && fully_acked && |
| 3155 | sack->rate->prior_delivered + 1 == tp->delivered && |
| 3156 | !(flag & (FLAG_CA_ALERT | FLAG_SYN_ACKED))) { |
| 3157 | /* Conservatively mark a delayed ACK. It's typically |
| 3158 | * from a lone runt packet over the round trip to |
| 3159 | * a receiver w/o out-of-order or CE events. |
| 3160 | */ |
| 3161 | flag |= FLAG_ACK_MAYBE_DELAYED; |
| 3162 | } |
Kenneth Klette Jonassen | 31231a8 | 2015-05-01 01:10:58 +0200 | [diff] [blame] | 3163 | } |
Eric Dumazet | 9a568de | 2017-05-16 14:00:14 -0700 | [diff] [blame] | 3164 | if (sack->first_sackt) { |
| 3165 | sack_rtt_us = tcp_stamp_us_delta(tp->tcp_mstamp, sack->first_sackt); |
| 3166 | ca_rtt_us = tcp_stamp_us_delta(tp->tcp_mstamp, sack->last_sackt); |
Eric Dumazet | 740b0f1 | 2014-02-26 14:02:48 -0800 | [diff] [blame] | 3167 | } |
Yuchung Cheng | f672258 | 2015-10-16 21:57:42 -0700 | [diff] [blame] | 3168 | rtt_update = tcp_ack_update_rtt(sk, flag, seq_rtt_us, sack_rtt_us, |
Yuchung Cheng | 775e68a | 2017-05-31 11:30:53 -0700 | [diff] [blame] | 3169 | ca_rtt_us, sack->rate); |
Yuchung Cheng | ed08495 | 2013-07-22 16:20:48 -0700 | [diff] [blame] | 3170 | |
Ilpo Järvinen | 7c46a03 | 2007-09-20 11:33:43 -0700 | [diff] [blame] | 3171 | if (flag & FLAG_ACKED) { |
Neal Cardwell | df92c83 | 2017-08-03 09:19:54 -0400 | [diff] [blame] | 3172 | flag |= FLAG_SET_XMIT_TIMER; /* set TLP or RTO timer */ |
Ilpo Järvinen | 72211e9 | 2009-03-14 14:23:04 +0000 | [diff] [blame] | 3173 | if (unlikely(icsk->icsk_mtup.probe_size && |
| 3174 | !after(tp->mtu_probe.probe_seq_end, tp->snd_una))) { |
| 3175 | tcp_mtup_probe_success(sk); |
| 3176 | } |
| 3177 | |
Ilpo Järvinen | c7caf8d | 2007-11-10 21:22:18 -0800 | [diff] [blame] | 3178 | if (tcp_is_reno(tp)) { |
| 3179 | tcp_remove_reno_sacks(sk, pkts_acked); |
Ilpo Järvinen | 1236f22 | 2018-06-29 13:07:53 +0300 | [diff] [blame] | 3180 | |
| 3181 | /* If any of the cumulatively ACKed segments was |
| 3182 | * retransmitted, non-SACK case cannot confirm that |
| 3183 | * progress was due to original transmission due to |
| 3184 | * lack of TCPCB_SACKED_ACKED bits even if some of |
| 3185 | * the packets may have been never retransmitted. |
| 3186 | */ |
| 3187 | if (flag & FLAG_RETRANS_DATA_ACKED) |
| 3188 | flag &= ~FLAG_ORIG_SACK_ACKED; |
Ilpo Järvinen | c7caf8d | 2007-11-10 21:22:18 -0800 | [diff] [blame] | 3189 | } else { |
Ilpo Järvinen | 59a08cb | 2009-02-28 04:44:28 +0000 | [diff] [blame] | 3190 | int delta; |
| 3191 | |
Ilpo Järvinen | c7caf8d | 2007-11-10 21:22:18 -0800 | [diff] [blame] | 3192 | /* Non-retransmitted hole got filled? That's reordering */ |
Yuchung Cheng | 737ff31 | 2017-11-08 13:01:27 -0800 | [diff] [blame] | 3193 | if (before(reord, prior_fack)) |
| 3194 | tcp_check_sack_reordering(sk, reord, 0); |
Ilpo Järvinen | 90638a0 | 2008-09-20 21:25:52 -0700 | [diff] [blame] | 3195 | |
Yuchung Cheng | 713bafe | 2017-11-08 13:01:26 -0800 | [diff] [blame] | 3196 | delta = prior_sacked - tp->sacked_out; |
Ilpo Järvinen | 59a08cb | 2009-02-28 04:44:28 +0000 | [diff] [blame] | 3197 | tp->lost_cnt_hint -= min(tp->lost_cnt_hint, delta); |
Ilpo Järvinen | c7caf8d | 2007-11-10 21:22:18 -0800 | [diff] [blame] | 3198 | } |
Eric Dumazet | 740b0f1 | 2014-02-26 14:02:48 -0800 | [diff] [blame] | 3199 | } else if (skb && rtt_update && sack_rtt_us >= 0 && |
Eric Dumazet | 2fd66ff | 2018-09-21 08:51:47 -0700 | [diff] [blame] | 3200 | sack_rtt_us > tcp_stamp_us_delta(tp->tcp_mstamp, |
| 3201 | tcp_skb_timestamp_us(skb))) { |
Yuchung Cheng | 2f715c1 | 2013-10-24 08:59:27 -0700 | [diff] [blame] | 3202 | /* Do not re-arm RTO if the sack RTT is measured from data sent |
| 3203 | * after when the head was last (re)transmitted. Otherwise the |
| 3204 | * timeout may continue to extend in loss recovery. |
| 3205 | */ |
Neal Cardwell | df92c83 | 2017-08-03 09:19:54 -0400 | [diff] [blame] | 3206 | flag |= FLAG_SET_XMIT_TIMER; /* set TLP or RTO timer */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3207 | } |
| 3208 | |
Lawrence Brakmo | 756ee17 | 2016-05-11 10:02:13 -0700 | [diff] [blame] | 3209 | if (icsk->icsk_ca_ops->pkts_acked) { |
| 3210 | struct ack_sample sample = { .pkts_acked = pkts_acked, |
Yuchung Cheng | 775e68a | 2017-05-31 11:30:53 -0700 | [diff] [blame] | 3211 | .rtt_us = sack->rate->rtt_us, |
Lawrence Brakmo | 6f094b9 | 2016-06-08 21:16:44 -0700 | [diff] [blame] | 3212 | .in_flight = last_in_flight }; |
Lawrence Brakmo | 756ee17 | 2016-05-11 10:02:13 -0700 | [diff] [blame] | 3213 | |
| 3214 | icsk->icsk_ca_ops->pkts_acked(sk, &sample); |
| 3215 | } |
Kenneth Klette Jonassen | 138998f | 2015-05-01 01:10:59 +0200 | [diff] [blame] | 3216 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3217 | #if FASTRETRANS_DEBUG > 0 |
Ilpo Järvinen | 547b792 | 2008-07-25 21:43:18 -0700 | [diff] [blame] | 3218 | WARN_ON((int)tp->sacked_out < 0); |
| 3219 | WARN_ON((int)tp->lost_out < 0); |
| 3220 | WARN_ON((int)tp->retrans_out < 0); |
Ilpo Järvinen | e60402d | 2007-08-09 15:14:46 +0300 | [diff] [blame] | 3221 | if (!tp->packets_out && tcp_is_sack(tp)) { |
Stephen Hemminger | cfcabdc | 2007-10-09 01:59:42 -0700 | [diff] [blame] | 3222 | icsk = inet_csk(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3223 | if (tp->lost_out) { |
Joe Perches | 91df42b | 2012-05-15 14:11:54 +0000 | [diff] [blame] | 3224 | pr_debug("Leak l=%u %d\n", |
| 3225 | tp->lost_out, icsk->icsk_ca_state); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3226 | tp->lost_out = 0; |
| 3227 | } |
| 3228 | if (tp->sacked_out) { |
Joe Perches | 91df42b | 2012-05-15 14:11:54 +0000 | [diff] [blame] | 3229 | pr_debug("Leak s=%u %d\n", |
| 3230 | tp->sacked_out, icsk->icsk_ca_state); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3231 | tp->sacked_out = 0; |
| 3232 | } |
| 3233 | if (tp->retrans_out) { |
Joe Perches | 91df42b | 2012-05-15 14:11:54 +0000 | [diff] [blame] | 3234 | pr_debug("Leak r=%u %d\n", |
| 3235 | tp->retrans_out, icsk->icsk_ca_state); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3236 | tp->retrans_out = 0; |
| 3237 | } |
| 3238 | } |
| 3239 | #endif |
Ilpo Järvinen | 7c46a03 | 2007-09-20 11:33:43 -0700 | [diff] [blame] | 3240 | return flag; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3241 | } |
| 3242 | |
| 3243 | static void tcp_ack_probe(struct sock *sk) |
| 3244 | { |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 3245 | struct inet_connection_sock *icsk = inet_csk(sk); |
Eric Dumazet | 75c119a | 2017-10-05 22:21:27 -0700 | [diff] [blame] | 3246 | struct sk_buff *head = tcp_send_head(sk); |
| 3247 | const struct tcp_sock *tp = tcp_sk(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3248 | |
| 3249 | /* Was it a usable window open? */ |
Eric Dumazet | 75c119a | 2017-10-05 22:21:27 -0700 | [diff] [blame] | 3250 | if (!head) |
| 3251 | return; |
| 3252 | if (!after(TCP_SKB_CB(head)->end_seq, tcp_wnd_end(tp))) { |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 3253 | icsk->icsk_backoff = 0; |
| 3254 | inet_csk_clear_xmit_timer(sk, ICSK_TIME_PROBE0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3255 | /* Socket must be waked up by subsequent tcp_data_snd_check(). |
| 3256 | * This function is not for random using! |
| 3257 | */ |
| 3258 | } else { |
Eric Dumazet | 21c8fe9 | 2015-05-06 14:26:24 -0700 | [diff] [blame] | 3259 | unsigned long when = tcp_probe0_when(sk, TCP_RTO_MAX); |
Eric Dumazet | fcdd1cf | 2014-09-22 13:19:44 -0700 | [diff] [blame] | 3260 | |
Eric Dumazet | 3f80e08 | 2018-10-23 11:54:16 -0700 | [diff] [blame] | 3261 | tcp_reset_xmit_timer(sk, ICSK_TIME_PROBE0, |
| 3262 | when, TCP_RTO_MAX, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3263 | } |
| 3264 | } |
| 3265 | |
Vijay Subramanian | 67b95bd | 2012-07-19 21:32:18 +0000 | [diff] [blame] | 3266 | static inline bool tcp_ack_is_dubious(const struct sock *sk, const int flag) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3267 | { |
Eric Dumazet | a02cec2 | 2010-09-22 20:43:57 +0000 | [diff] [blame] | 3268 | return !(flag & FLAG_NOT_DUP) || (flag & FLAG_CA_ALERT) || |
| 3269 | inet_csk(sk)->icsk_ca_state != TCP_CA_Open; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3270 | } |
| 3271 | |
Yuchung Cheng | 0f7cc9a | 2013-08-21 17:29:23 -0700 | [diff] [blame] | 3272 | /* Decide wheather to run the increase function of congestion control. */ |
Vijay Subramanian | 67b95bd | 2012-07-19 21:32:18 +0000 | [diff] [blame] | 3273 | static inline bool tcp_may_raise_cwnd(const struct sock *sk, const int flag) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3274 | { |
Yuchung Cheng | 0f7cc9a | 2013-08-21 17:29:23 -0700 | [diff] [blame] | 3275 | /* If reordering is high then always grow cwnd whenever data is |
| 3276 | * delivered regardless of its ordering. Otherwise stay conservative |
Yuchung Cheng | 16edfe7 | 2013-09-05 15:36:09 -0700 | [diff] [blame] | 3277 | * and only grow cwnd on in-order delivery (RFC5681). A stretched ACK w/ |
Yuchung Cheng | 0f7cc9a | 2013-08-21 17:29:23 -0700 | [diff] [blame] | 3278 | * new SACK or ECE mark may first advance cwnd here and later reduce |
| 3279 | * cwnd in tcp_fastretrans_alert() based on more states. |
| 3280 | */ |
Nikolay Borisov | 1043e25 | 2016-02-03 09:46:52 +0200 | [diff] [blame] | 3281 | if (tcp_sk(sk)->reordering > sock_net(sk)->ipv4.sysctl_tcp_reordering) |
Yuchung Cheng | 0f7cc9a | 2013-08-21 17:29:23 -0700 | [diff] [blame] | 3282 | return flag & FLAG_FORWARD_PROGRESS; |
| 3283 | |
Yuchung Cheng | 16edfe7 | 2013-09-05 15:36:09 -0700 | [diff] [blame] | 3284 | return flag & FLAG_DATA_ACKED; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3285 | } |
| 3286 | |
Yuchung Cheng | d452e6c | 2016-02-02 10:33:09 -0800 | [diff] [blame] | 3287 | /* The "ultimate" congestion control function that aims to replace the rigid |
| 3288 | * cwnd increase and decrease control (tcp_cong_avoid,tcp_*cwnd_reduction). |
| 3289 | * It's called toward the end of processing an ACK with precise rate |
| 3290 | * information. All transmission or retransmission are delayed afterwards. |
| 3291 | */ |
| 3292 | static void tcp_cong_control(struct sock *sk, u32 ack, u32 acked_sacked, |
Yuchung Cheng | c040276 | 2016-09-19 23:39:21 -0400 | [diff] [blame] | 3293 | int flag, const struct rate_sample *rs) |
Yuchung Cheng | d452e6c | 2016-02-02 10:33:09 -0800 | [diff] [blame] | 3294 | { |
Yuchung Cheng | c040276 | 2016-09-19 23:39:21 -0400 | [diff] [blame] | 3295 | const struct inet_connection_sock *icsk = inet_csk(sk); |
| 3296 | |
| 3297 | if (icsk->icsk_ca_ops->cong_control) { |
| 3298 | icsk->icsk_ca_ops->cong_control(sk, rs); |
| 3299 | return; |
| 3300 | } |
| 3301 | |
Yuchung Cheng | d452e6c | 2016-02-02 10:33:09 -0800 | [diff] [blame] | 3302 | if (tcp_in_cwnd_reduction(sk)) { |
| 3303 | /* Reduce cwnd if state mandates */ |
| 3304 | tcp_cwnd_reduction(sk, acked_sacked, flag); |
| 3305 | } else if (tcp_may_raise_cwnd(sk, flag)) { |
| 3306 | /* Advance cwnd if state allows */ |
| 3307 | tcp_cong_avoid(sk, ack, acked_sacked); |
| 3308 | } |
| 3309 | tcp_update_pacing_rate(sk); |
| 3310 | } |
| 3311 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3312 | /* Check that window update is acceptable. |
| 3313 | * The function assumes that snd_una<=ack<=snd_next. |
| 3314 | */ |
Vijay Subramanian | 67b95bd | 2012-07-19 21:32:18 +0000 | [diff] [blame] | 3315 | static inline bool tcp_may_update_window(const struct tcp_sock *tp, |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 3316 | const u32 ack, const u32 ack_seq, |
| 3317 | const u32 nwin) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3318 | { |
Eric Dumazet | a02cec2 | 2010-09-22 20:43:57 +0000 | [diff] [blame] | 3319 | return after(ack, tp->snd_una) || |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3320 | after(ack_seq, tp->snd_wl1) || |
Eric Dumazet | a02cec2 | 2010-09-22 20:43:57 +0000 | [diff] [blame] | 3321 | (ack_seq == tp->snd_wl1 && nwin > tp->snd_wnd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3322 | } |
| 3323 | |
Eric Dumazet | 0df48c2 | 2015-04-28 15:28:17 -0700 | [diff] [blame] | 3324 | /* If we update tp->snd_una, also update tp->bytes_acked */ |
| 3325 | static void tcp_snd_una_update(struct tcp_sock *tp, u32 ack) |
| 3326 | { |
| 3327 | u32 delta = ack - tp->snd_una; |
| 3328 | |
Eric Dumazet | 46cc6e4 | 2016-05-03 16:56:03 -0700 | [diff] [blame] | 3329 | sock_owned_by_me((struct sock *)tp); |
Eric Dumazet | 0df48c2 | 2015-04-28 15:28:17 -0700 | [diff] [blame] | 3330 | tp->bytes_acked += delta; |
| 3331 | tp->snd_una = ack; |
| 3332 | } |
| 3333 | |
Eric Dumazet | bdd1f9e | 2015-04-28 15:28:18 -0700 | [diff] [blame] | 3334 | /* If we update tp->rcv_nxt, also update tp->bytes_received */ |
| 3335 | static void tcp_rcv_nxt_update(struct tcp_sock *tp, u32 seq) |
| 3336 | { |
| 3337 | u32 delta = seq - tp->rcv_nxt; |
| 3338 | |
Eric Dumazet | 46cc6e4 | 2016-05-03 16:56:03 -0700 | [diff] [blame] | 3339 | sock_owned_by_me((struct sock *)tp); |
Eric Dumazet | bdd1f9e | 2015-04-28 15:28:18 -0700 | [diff] [blame] | 3340 | tp->bytes_received += delta; |
| 3341 | tp->rcv_nxt = seq; |
| 3342 | } |
| 3343 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3344 | /* Update our send window. |
| 3345 | * |
| 3346 | * Window update algorithm, described in RFC793/RFC1122 (used in linux-2.2 |
| 3347 | * and in FreeBSD. NetBSD's one is even worse.) is wrong. |
| 3348 | */ |
Eric Dumazet | cf533ea | 2011-10-21 05:22:42 -0400 | [diff] [blame] | 3349 | static int tcp_ack_update_window(struct sock *sk, const struct sk_buff *skb, u32 ack, |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 3350 | u32 ack_seq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3351 | { |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 3352 | struct tcp_sock *tp = tcp_sk(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3353 | int flag = 0; |
Arnaldo Carvalho de Melo | aa8223c | 2007-04-10 21:04:22 -0700 | [diff] [blame] | 3354 | u32 nwin = ntohs(tcp_hdr(skb)->window); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3355 | |
Arnaldo Carvalho de Melo | aa8223c | 2007-04-10 21:04:22 -0700 | [diff] [blame] | 3356 | if (likely(!tcp_hdr(skb)->syn)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3357 | nwin <<= tp->rx_opt.snd_wscale; |
| 3358 | |
| 3359 | if (tcp_may_update_window(tp, ack, ack_seq, nwin)) { |
| 3360 | flag |= FLAG_WIN_UPDATE; |
Hantzis Fotis | ee7537b | 2009-03-02 22:42:02 -0800 | [diff] [blame] | 3361 | tcp_update_wl(tp, ack_seq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3362 | |
| 3363 | if (tp->snd_wnd != nwin) { |
| 3364 | tp->snd_wnd = nwin; |
| 3365 | |
Florian Westphal | 31770e3 | 2017-08-30 19:24:58 +0200 | [diff] [blame] | 3366 | /* Note, it is the only place, where |
| 3367 | * fast path is recovered for sending TCP. |
| 3368 | */ |
| 3369 | tp->pred_flags = 0; |
| 3370 | tcp_fast_path_check(sk); |
| 3371 | |
Eric Dumazet | 75c119a | 2017-10-05 22:21:27 -0700 | [diff] [blame] | 3372 | if (!tcp_write_queue_empty(sk)) |
Eric Dumazet | 6f021c6 | 2015-08-21 12:30:00 -0700 | [diff] [blame] | 3373 | tcp_slow_start_after_idle_check(sk); |
| 3374 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3375 | if (nwin > tp->max_window) { |
| 3376 | tp->max_window = nwin; |
Arnaldo Carvalho de Melo | d83d846 | 2005-12-13 23:26:10 -0800 | [diff] [blame] | 3377 | tcp_sync_mss(sk, inet_csk(sk)->icsk_pmtu_cookie); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3378 | } |
| 3379 | } |
| 3380 | } |
| 3381 | |
Eric Dumazet | 0df48c2 | 2015-04-28 15:28:17 -0700 | [diff] [blame] | 3382 | tcp_snd_una_update(tp, ack); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3383 | |
| 3384 | return flag; |
| 3385 | } |
| 3386 | |
Jason Baron | 083ae30 | 2016-07-14 11:38:40 -0400 | [diff] [blame] | 3387 | static bool __tcp_oow_rate_limited(struct net *net, int mib_idx, |
| 3388 | u32 *last_oow_ack_time) |
| 3389 | { |
| 3390 | if (*last_oow_ack_time) { |
Eric Dumazet | 594208a | 2017-05-16 14:00:10 -0700 | [diff] [blame] | 3391 | s32 elapsed = (s32)(tcp_jiffies32 - *last_oow_ack_time); |
Jason Baron | 083ae30 | 2016-07-14 11:38:40 -0400 | [diff] [blame] | 3392 | |
Eric Dumazet | 4170ba6 | 2017-10-27 07:47:30 -0700 | [diff] [blame] | 3393 | if (0 <= elapsed && elapsed < net->ipv4.sysctl_tcp_invalid_ratelimit) { |
Jason Baron | 083ae30 | 2016-07-14 11:38:40 -0400 | [diff] [blame] | 3394 | NET_INC_STATS(net, mib_idx); |
| 3395 | return true; /* rate-limited: don't send yet! */ |
| 3396 | } |
| 3397 | } |
| 3398 | |
Eric Dumazet | 594208a | 2017-05-16 14:00:10 -0700 | [diff] [blame] | 3399 | *last_oow_ack_time = tcp_jiffies32; |
Jason Baron | 083ae30 | 2016-07-14 11:38:40 -0400 | [diff] [blame] | 3400 | |
| 3401 | return false; /* not rate-limited: go ahead, send dupack now! */ |
| 3402 | } |
| 3403 | |
Eric Dumazet | 7970ddc | 2015-03-16 21:06:20 -0700 | [diff] [blame] | 3404 | /* Return true if we're currently rate-limiting out-of-window ACKs and |
| 3405 | * thus shouldn't send a dupack right now. We rate-limit dupacks in |
| 3406 | * response to out-of-window SYNs or ACKs to mitigate ACK loops or DoS |
| 3407 | * attacks that send repeated SYNs or ACKs for the same connection. To |
| 3408 | * do this, we do not send a duplicate SYNACK or ACK if the remote |
| 3409 | * endpoint is sending out-of-window SYNs or pure ACKs at a high rate. |
| 3410 | */ |
| 3411 | bool tcp_oow_rate_limited(struct net *net, const struct sk_buff *skb, |
| 3412 | int mib_idx, u32 *last_oow_ack_time) |
| 3413 | { |
| 3414 | /* Data packets without SYNs are not likely part of an ACK loop. */ |
| 3415 | if ((TCP_SKB_CB(skb)->seq != TCP_SKB_CB(skb)->end_seq) && |
| 3416 | !tcp_hdr(skb)->syn) |
Jason Baron | 083ae30 | 2016-07-14 11:38:40 -0400 | [diff] [blame] | 3417 | return false; |
Eric Dumazet | 7970ddc | 2015-03-16 21:06:20 -0700 | [diff] [blame] | 3418 | |
Jason Baron | 083ae30 | 2016-07-14 11:38:40 -0400 | [diff] [blame] | 3419 | return __tcp_oow_rate_limited(net, mib_idx, last_oow_ack_time); |
Eric Dumazet | 7970ddc | 2015-03-16 21:06:20 -0700 | [diff] [blame] | 3420 | } |
| 3421 | |
Eric Dumazet | 354e4aa | 2012-10-21 19:57:11 +0000 | [diff] [blame] | 3422 | /* RFC 5961 7 [ACK Throttling] */ |
Neal Cardwell | f2b2c58 | 2015-02-06 16:04:40 -0500 | [diff] [blame] | 3423 | static void tcp_send_challenge_ack(struct sock *sk, const struct sk_buff *skb) |
Eric Dumazet | 354e4aa | 2012-10-21 19:57:11 +0000 | [diff] [blame] | 3424 | { |
| 3425 | /* unprotected vars, we dont care of overwrites */ |
| 3426 | static u32 challenge_timestamp; |
| 3427 | static unsigned int challenge_count; |
Neal Cardwell | f2b2c58 | 2015-02-06 16:04:40 -0500 | [diff] [blame] | 3428 | struct tcp_sock *tp = tcp_sk(sk); |
Eric Dumazet | b530b68 | 2017-10-27 07:47:26 -0700 | [diff] [blame] | 3429 | struct net *net = sock_net(sk); |
Eric Dumazet | 75ff39c | 2016-07-10 10:04:02 +0200 | [diff] [blame] | 3430 | u32 count, now; |
Eric Dumazet | 354e4aa | 2012-10-21 19:57:11 +0000 | [diff] [blame] | 3431 | |
Neal Cardwell | f2b2c58 | 2015-02-06 16:04:40 -0500 | [diff] [blame] | 3432 | /* First check our per-socket dupack rate limit. */ |
Eric Dumazet | b530b68 | 2017-10-27 07:47:26 -0700 | [diff] [blame] | 3433 | if (__tcp_oow_rate_limited(net, |
Jason Baron | 083ae30 | 2016-07-14 11:38:40 -0400 | [diff] [blame] | 3434 | LINUX_MIB_TCPACKSKIPPEDCHALLENGE, |
| 3435 | &tp->last_oow_ack_time)) |
Neal Cardwell | f2b2c58 | 2015-02-06 16:04:40 -0500 | [diff] [blame] | 3436 | return; |
| 3437 | |
Eric Dumazet | 75ff39c | 2016-07-10 10:04:02 +0200 | [diff] [blame] | 3438 | /* Then check host-wide RFC 5961 rate limit. */ |
Neal Cardwell | f2b2c58 | 2015-02-06 16:04:40 -0500 | [diff] [blame] | 3439 | now = jiffies / HZ; |
Eric Dumazet | 354e4aa | 2012-10-21 19:57:11 +0000 | [diff] [blame] | 3440 | if (now != challenge_timestamp) { |
Eric Dumazet | b530b68 | 2017-10-27 07:47:26 -0700 | [diff] [blame] | 3441 | u32 ack_limit = net->ipv4.sysctl_tcp_challenge_ack_limit; |
| 3442 | u32 half = (ack_limit + 1) >> 1; |
Eric Dumazet | 75ff39c | 2016-07-10 10:04:02 +0200 | [diff] [blame] | 3443 | |
Eric Dumazet | 354e4aa | 2012-10-21 19:57:11 +0000 | [diff] [blame] | 3444 | challenge_timestamp = now; |
Eric Dumazet | b530b68 | 2017-10-27 07:47:26 -0700 | [diff] [blame] | 3445 | WRITE_ONCE(challenge_count, half + prandom_u32_max(ack_limit)); |
Eric Dumazet | 354e4aa | 2012-10-21 19:57:11 +0000 | [diff] [blame] | 3446 | } |
Eric Dumazet | 75ff39c | 2016-07-10 10:04:02 +0200 | [diff] [blame] | 3447 | count = READ_ONCE(challenge_count); |
| 3448 | if (count > 0) { |
| 3449 | WRITE_ONCE(challenge_count, count - 1); |
Eric Dumazet | b530b68 | 2017-10-27 07:47:26 -0700 | [diff] [blame] | 3450 | NET_INC_STATS(net, LINUX_MIB_TCPCHALLENGEACK); |
Eric Dumazet | 354e4aa | 2012-10-21 19:57:11 +0000 | [diff] [blame] | 3451 | tcp_send_ack(sk); |
| 3452 | } |
| 3453 | } |
| 3454 | |
Eric Dumazet | 12fb3dd | 2013-04-19 07:19:48 +0000 | [diff] [blame] | 3455 | static void tcp_store_ts_recent(struct tcp_sock *tp) |
| 3456 | { |
| 3457 | tp->rx_opt.ts_recent = tp->rx_opt.rcv_tsval; |
Arnd Bergmann | cca9bab | 2018-07-11 12:16:12 +0200 | [diff] [blame] | 3458 | tp->rx_opt.ts_recent_stamp = ktime_get_seconds(); |
Eric Dumazet | 12fb3dd | 2013-04-19 07:19:48 +0000 | [diff] [blame] | 3459 | } |
| 3460 | |
| 3461 | static void tcp_replace_ts_recent(struct tcp_sock *tp, u32 seq) |
| 3462 | { |
| 3463 | if (tp->rx_opt.saw_tstamp && !after(seq, tp->rcv_wup)) { |
| 3464 | /* PAWS bug workaround wrt. ACK frames, the PAWS discard |
| 3465 | * extra check below makes sure this can only happen |
| 3466 | * for pure ACK frames. -DaveM |
| 3467 | * |
| 3468 | * Not only, also it occurs for expired timestamps. |
| 3469 | */ |
| 3470 | |
| 3471 | if (tcp_paws_check(&tp->rx_opt, 0)) |
| 3472 | tcp_store_ts_recent(tp); |
| 3473 | } |
| 3474 | } |
| 3475 | |
Nandita Dukkipati | 9b717a8 | 2013-03-11 10:00:44 +0000 | [diff] [blame] | 3476 | /* This routine deals with acks during a TLP episode. |
Sébastien Barré | 08abdff | 2015-01-12 10:30:40 +0100 | [diff] [blame] | 3477 | * We mark the end of a TLP episode on receiving TLP dupack or when |
| 3478 | * ack is after tlp_high_seq. |
Nandita Dukkipati | 9b717a8 | 2013-03-11 10:00:44 +0000 | [diff] [blame] | 3479 | * Ref: loss detection algorithm in draft-dukkipati-tcpm-tcp-loss-probe. |
| 3480 | */ |
| 3481 | static void tcp_process_tlp_ack(struct sock *sk, u32 ack, int flag) |
| 3482 | { |
| 3483 | struct tcp_sock *tp = tcp_sk(sk); |
Nandita Dukkipati | 9b717a8 | 2013-03-11 10:00:44 +0000 | [diff] [blame] | 3484 | |
Sébastien Barré | 08abdff | 2015-01-12 10:30:40 +0100 | [diff] [blame] | 3485 | if (before(ack, tp->tlp_high_seq)) |
Nandita Dukkipati | 9b717a8 | 2013-03-11 10:00:44 +0000 | [diff] [blame] | 3486 | return; |
Nandita Dukkipati | 9b717a8 | 2013-03-11 10:00:44 +0000 | [diff] [blame] | 3487 | |
Sébastien Barré | 08abdff | 2015-01-12 10:30:40 +0100 | [diff] [blame] | 3488 | if (flag & FLAG_DSACKING_ACK) { |
| 3489 | /* This DSACK means original and TLP probe arrived; no loss */ |
Nandita Dukkipati | 9b717a8 | 2013-03-11 10:00:44 +0000 | [diff] [blame] | 3490 | tp->tlp_high_seq = 0; |
Sébastien Barré | 08abdff | 2015-01-12 10:30:40 +0100 | [diff] [blame] | 3491 | } else if (after(ack, tp->tlp_high_seq)) { |
| 3492 | /* ACK advances: there was a loss, so reduce cwnd. Reset |
| 3493 | * tlp_high_seq in tcp_init_cwnd_reduction() |
| 3494 | */ |
| 3495 | tcp_init_cwnd_reduction(sk); |
| 3496 | tcp_set_ca_state(sk, TCP_CA_CWR); |
| 3497 | tcp_end_cwnd_reduction(sk); |
| 3498 | tcp_try_keep_open(sk); |
Eric Dumazet | c10d931 | 2016-04-29 14:16:47 -0700 | [diff] [blame] | 3499 | NET_INC_STATS(sock_net(sk), |
Eric Dumazet | 02a1d6e | 2016-04-27 16:44:39 -0700 | [diff] [blame] | 3500 | LINUX_MIB_TCPLOSSPROBERECOVERY); |
Sébastien Barré | 08abdff | 2015-01-12 10:30:40 +0100 | [diff] [blame] | 3501 | } else if (!(flag & (FLAG_SND_UNA_ADVANCED | |
| 3502 | FLAG_NOT_DUP | FLAG_DATA_SACKED))) { |
| 3503 | /* Pure dupack: original and TLP probe arrived; no loss */ |
| 3504 | tp->tlp_high_seq = 0; |
Nandita Dukkipati | 9b717a8 | 2013-03-11 10:00:44 +0000 | [diff] [blame] | 3505 | } |
| 3506 | } |
| 3507 | |
Florian Westphal | 7354c8c | 2014-09-26 22:37:34 +0200 | [diff] [blame] | 3508 | static inline void tcp_in_ack_event(struct sock *sk, u32 flags) |
| 3509 | { |
| 3510 | const struct inet_connection_sock *icsk = inet_csk(sk); |
| 3511 | |
| 3512 | if (icsk->icsk_ca_ops->in_ack_event) |
| 3513 | icsk->icsk_ca_ops->in_ack_event(sk, flags); |
| 3514 | } |
| 3515 | |
Yuchung Cheng | e662ca4 | 2016-02-02 10:33:04 -0800 | [diff] [blame] | 3516 | /* Congestion control has updated the cwnd already. So if we're in |
| 3517 | * loss recovery then now we do any new sends (for FRTO) or |
| 3518 | * retransmits (for CA_Loss or CA_recovery) that make sense. |
| 3519 | */ |
| 3520 | static void tcp_xmit_recovery(struct sock *sk, int rexmit) |
| 3521 | { |
| 3522 | struct tcp_sock *tp = tcp_sk(sk); |
| 3523 | |
| 3524 | if (rexmit == REXMIT_NONE) |
| 3525 | return; |
| 3526 | |
| 3527 | if (unlikely(rexmit == 2)) { |
| 3528 | __tcp_push_pending_frames(sk, tcp_current_mss(sk), |
| 3529 | TCP_NAGLE_OFF); |
| 3530 | if (after(tp->snd_nxt, tp->high_seq)) |
| 3531 | return; |
| 3532 | tp->frto = 0; |
| 3533 | } |
| 3534 | tcp_xmit_retransmit_queue(sk); |
| 3535 | } |
| 3536 | |
Yuchung Cheng | a77fa01 | 2018-04-17 23:18:47 -0700 | [diff] [blame] | 3537 | /* Returns the number of packets newly acked or sacked by the current ACK */ |
| 3538 | static u32 tcp_newly_delivered(struct sock *sk, u32 prior_delivered, int flag) |
| 3539 | { |
Yuchung Cheng | feb5f2e | 2018-04-17 23:18:49 -0700 | [diff] [blame] | 3540 | const struct net *net = sock_net(sk); |
Yuchung Cheng | a77fa01 | 2018-04-17 23:18:47 -0700 | [diff] [blame] | 3541 | struct tcp_sock *tp = tcp_sk(sk); |
| 3542 | u32 delivered; |
| 3543 | |
| 3544 | delivered = tp->delivered - prior_delivered; |
Yuchung Cheng | feb5f2e | 2018-04-17 23:18:49 -0700 | [diff] [blame] | 3545 | NET_ADD_STATS(net, LINUX_MIB_TCPDELIVERED, delivered); |
| 3546 | if (flag & FLAG_ECE) { |
Yuchung Cheng | e21db6f | 2018-04-17 23:18:48 -0700 | [diff] [blame] | 3547 | tp->delivered_ce += delivered; |
Yuchung Cheng | feb5f2e | 2018-04-17 23:18:49 -0700 | [diff] [blame] | 3548 | NET_ADD_STATS(net, LINUX_MIB_TCPDELIVEREDCE, delivered); |
| 3549 | } |
Yuchung Cheng | a77fa01 | 2018-04-17 23:18:47 -0700 | [diff] [blame] | 3550 | return delivered; |
| 3551 | } |
| 3552 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3553 | /* This routine deals with incoming acks, but not outgoing ones. */ |
Eric Dumazet | cf533ea | 2011-10-21 05:22:42 -0400 | [diff] [blame] | 3554 | static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3555 | { |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 3556 | struct inet_connection_sock *icsk = inet_csk(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3557 | struct tcp_sock *tp = tcp_sk(sk); |
Kenneth Klette Jonassen | 196da97 | 2015-05-01 01:10:57 +0200 | [diff] [blame] | 3558 | struct tcp_sacktag_state sack_state; |
Yuchung Cheng | b9f6482 | 2016-09-19 23:39:14 -0400 | [diff] [blame] | 3559 | struct rate_sample rs = { .prior_delivered = 0 }; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3560 | u32 prior_snd_una = tp->snd_una; |
Yousuk Seung | d476175 | 2017-12-07 13:41:34 -0800 | [diff] [blame] | 3561 | bool is_sack_reneg = tp->is_sack_reneg; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3562 | u32 ack_seq = TCP_SKB_CB(skb)->seq; |
| 3563 | u32 ack = TCP_SKB_CB(skb)->ack_seq; |
Eric Dumazet | 19119f2 | 2018-11-27 14:42:01 -0800 | [diff] [blame] | 3564 | int num_dupack = 0; |
Nandita Dukkipati | 35f079e | 2013-05-21 15:12:07 +0000 | [diff] [blame] | 3565 | int prior_packets = tp->packets_out; |
Yuchung Cheng | b9f6482 | 2016-09-19 23:39:14 -0400 | [diff] [blame] | 3566 | u32 delivered = tp->delivered; |
| 3567 | u32 lost = tp->lost; |
Yuchung Cheng | e662ca4 | 2016-02-02 10:33:04 -0800 | [diff] [blame] | 3568 | int rexmit = REXMIT_NONE; /* Flag to (re)transmit to recover losses */ |
Yuchung Cheng | 737ff31 | 2017-11-08 13:01:27 -0800 | [diff] [blame] | 3569 | u32 prior_fack; |
Kenneth Klette Jonassen | 196da97 | 2015-05-01 01:10:57 +0200 | [diff] [blame] | 3570 | |
Eric Dumazet | 9a568de | 2017-05-16 14:00:14 -0700 | [diff] [blame] | 3571 | sack_state.first_sackt = 0; |
Yuchung Cheng | b9f6482 | 2016-09-19 23:39:14 -0400 | [diff] [blame] | 3572 | sack_state.rate = &rs; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3573 | |
Eric Dumazet | 75c119a | 2017-10-05 22:21:27 -0700 | [diff] [blame] | 3574 | /* We very likely will need to access rtx queue. */ |
| 3575 | prefetch(sk->tcp_rtx_queue.rb_node); |
Eric Dumazet | ad971f6 | 2014-10-11 15:17:29 -0700 | [diff] [blame] | 3576 | |
John Dykstra | 96e0bf4 | 2009-03-22 21:49:57 -0700 | [diff] [blame] | 3577 | /* If the ack is older than previous acks |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3578 | * then we can probably ignore it. |
| 3579 | */ |
Eric Dumazet | 354e4aa | 2012-10-21 19:57:11 +0000 | [diff] [blame] | 3580 | if (before(ack, prior_snd_una)) { |
| 3581 | /* RFC 5961 5.2 [Blind Data Injection Attack].[Mitigation] */ |
| 3582 | if (before(ack, prior_snd_una - tp->max_window)) { |
Eric Dumazet | d0e1a1b | 2017-05-23 15:24:46 -0700 | [diff] [blame] | 3583 | if (!(flag & FLAG_NO_CHALLENGE_ACK)) |
| 3584 | tcp_send_challenge_ack(sk, skb); |
Eric Dumazet | 354e4aa | 2012-10-21 19:57:11 +0000 | [diff] [blame] | 3585 | return -1; |
| 3586 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3587 | goto old_ack; |
Eric Dumazet | 354e4aa | 2012-10-21 19:57:11 +0000 | [diff] [blame] | 3588 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3589 | |
John Dykstra | 96e0bf4 | 2009-03-22 21:49:57 -0700 | [diff] [blame] | 3590 | /* If the ack includes data we haven't sent yet, discard |
| 3591 | * this segment (RFC793 Section 3.9). |
| 3592 | */ |
| 3593 | if (after(ack, tp->snd_nxt)) |
Yafang Shao | 9946b34 | 2019-02-25 18:33:48 +0800 | [diff] [blame] | 3594 | return -1; |
John Dykstra | 96e0bf4 | 2009-03-22 21:49:57 -0700 | [diff] [blame] | 3595 | |
Neal Cardwell | 0c9ab09 | 2014-08-14 16:13:07 -0400 | [diff] [blame] | 3596 | if (after(ack, prior_snd_una)) { |
Ilpo Järvinen | 2e60529 | 2007-08-02 19:46:58 -0700 | [diff] [blame] | 3597 | flag |= FLAG_SND_UNA_ADVANCED; |
Neal Cardwell | 0c9ab09 | 2014-08-14 16:13:07 -0400 | [diff] [blame] | 3598 | icsk->icsk_retransmits = 0; |
Ilya Lesokhin | 6dac152 | 2018-04-30 10:16:10 +0300 | [diff] [blame] | 3599 | |
| 3600 | #if IS_ENABLED(CONFIG_TLS_DEVICE) |
| 3601 | if (static_branch_unlikely(&clean_acked_data_enabled)) |
| 3602 | if (icsk->icsk_clean_acked) |
| 3603 | icsk->icsk_clean_acked(sk, ack); |
| 3604 | #endif |
Neal Cardwell | 0c9ab09 | 2014-08-14 16:13:07 -0400 | [diff] [blame] | 3605 | } |
Ilpo Järvinen | 2e60529 | 2007-08-02 19:46:58 -0700 | [diff] [blame] | 3606 | |
Eric Dumazet | 50895b9 | 2017-11-14 21:02:19 -0800 | [diff] [blame] | 3607 | prior_fack = tcp_is_sack(tp) ? tcp_highest_sack_seq(tp) : tp->snd_una; |
Yuchung Cheng | b9f6482 | 2016-09-19 23:39:14 -0400 | [diff] [blame] | 3608 | rs.prior_in_flight = tcp_packets_in_flight(tp); |
Ilpo Järvinen | c7caf8d | 2007-11-10 21:22:18 -0800 | [diff] [blame] | 3609 | |
Eric Dumazet | 12fb3dd | 2013-04-19 07:19:48 +0000 | [diff] [blame] | 3610 | /* ts_recent update must be made after we are sure that the packet |
| 3611 | * is in window. |
| 3612 | */ |
| 3613 | if (flag & FLAG_UPDATE_TS_RECENT) |
| 3614 | tcp_replace_ts_recent(tp, TCP_SKB_CB(skb)->seq); |
| 3615 | |
Yafang Shao | 5e13a0d | 2018-11-11 20:10:10 +0800 | [diff] [blame] | 3616 | if ((flag & (FLAG_SLOWPATH | FLAG_SND_UNA_ADVANCED)) == |
| 3617 | FLAG_SND_UNA_ADVANCED) { |
Florian Westphal | 31770e3 | 2017-08-30 19:24:58 +0200 | [diff] [blame] | 3618 | /* Window is constant, pure forward advance. |
| 3619 | * No more checks are required. |
| 3620 | * Note, we use the fact that SND.UNA>=SND.WL2. |
| 3621 | */ |
| 3622 | tcp_update_wl(tp, ack_seq); |
| 3623 | tcp_snd_una_update(tp, ack); |
| 3624 | flag |= FLAG_WIN_UPDATE; |
| 3625 | |
| 3626 | tcp_in_ack_event(sk, CA_ACK_WIN_UPDATE); |
| 3627 | |
| 3628 | NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPHPACKS); |
| 3629 | } else { |
Florian Westphal | c1d2b4c | 2017-08-30 19:24:57 +0200 | [diff] [blame] | 3630 | u32 ack_ev_flags = CA_ACK_SLOWPATH; |
Florian Westphal | 9890092 | 2014-09-26 22:37:35 +0200 | [diff] [blame] | 3631 | |
Florian Westphal | c1d2b4c | 2017-08-30 19:24:57 +0200 | [diff] [blame] | 3632 | if (ack_seq != TCP_SKB_CB(skb)->end_seq) |
| 3633 | flag |= FLAG_DATA; |
| 3634 | else |
| 3635 | NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPPUREACKS); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3636 | |
Florian Westphal | c1d2b4c | 2017-08-30 19:24:57 +0200 | [diff] [blame] | 3637 | flag |= tcp_ack_update_window(sk, skb, ack, ack_seq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3638 | |
Florian Westphal | c1d2b4c | 2017-08-30 19:24:57 +0200 | [diff] [blame] | 3639 | if (TCP_SKB_CB(skb)->sacked) |
| 3640 | flag |= tcp_sacktag_write_queue(sk, skb, prior_snd_una, |
| 3641 | &sack_state); |
| 3642 | |
| 3643 | if (tcp_ecn_rcv_ecn_echo(tp, tcp_hdr(skb))) { |
| 3644 | flag |= FLAG_ECE; |
| 3645 | ack_ev_flags |= CA_ACK_ECE; |
| 3646 | } |
| 3647 | |
| 3648 | if (flag & FLAG_WIN_UPDATE) |
| 3649 | ack_ev_flags |= CA_ACK_WIN_UPDATE; |
| 3650 | |
| 3651 | tcp_in_ack_event(sk, ack_ev_flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3652 | } |
| 3653 | |
| 3654 | /* We passed data and got it acked, remove any soft error |
| 3655 | * log. Something worked... |
| 3656 | */ |
| 3657 | sk->sk_err_soft = 0; |
David S. Miller | 4b53fb6 | 2008-07-23 16:38:45 -0700 | [diff] [blame] | 3658 | icsk->icsk_probes_out = 0; |
Eric Dumazet | 70eabf0 | 2017-05-16 14:00:07 -0700 | [diff] [blame] | 3659 | tp->rcv_tstamp = tcp_jiffies32; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3660 | if (!prior_packets) |
| 3661 | goto no_queue; |
| 3662 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3663 | /* See if we can take anything off of the retransmit queue. */ |
Yuchung Cheng | 737ff31 | 2017-11-08 13:01:27 -0800 | [diff] [blame] | 3664 | flag |= tcp_clean_rtx_queue(sk, prior_fack, prior_snd_una, &sack_state); |
Nandita Dukkipati | a262f0c | 2011-08-21 20:21:57 +0000 | [diff] [blame] | 3665 | |
Priyaranjan Jha | 1f25569 | 2017-11-03 16:38:48 -0700 | [diff] [blame] | 3666 | tcp_rack_update_reo_wnd(sk, &rs); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3667 | |
Neal Cardwell | df92c83 | 2017-08-03 09:19:54 -0400 | [diff] [blame] | 3668 | if (tp->tlp_high_seq) |
| 3669 | tcp_process_tlp_ack(sk, ack, flag); |
| 3670 | /* If needed, reset TLP/RTO timer; RACK may later override this. */ |
| 3671 | if (flag & FLAG_SET_XMIT_TIMER) |
| 3672 | tcp_set_xmit_timer(sk); |
| 3673 | |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 3674 | if (tcp_ack_is_dubious(sk, flag)) { |
Eric Dumazet | 19119f2 | 2018-11-27 14:42:01 -0800 | [diff] [blame] | 3675 | if (!(flag & (FLAG_SND_UNA_ADVANCED | FLAG_NOT_DUP))) { |
| 3676 | num_dupack = 1; |
| 3677 | /* Consider if pure acks were aggregated in tcp_add_backlog() */ |
| 3678 | if (!(flag & FLAG_DATA)) |
| 3679 | num_dupack = max_t(u16, 1, skb_shinfo(skb)->gso_segs); |
| 3680 | } |
| 3681 | tcp_fastretrans_alert(sk, prior_snd_una, num_dupack, &flag, |
Yuchung Cheng | 737ff31 | 2017-11-08 13:01:27 -0800 | [diff] [blame] | 3682 | &rexmit); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3683 | } |
Nandita Dukkipati | 9b717a8 | 2013-03-11 10:00:44 +0000 | [diff] [blame] | 3684 | |
Julian Anastasov | c3a2e83 | 2017-02-06 23:14:14 +0200 | [diff] [blame] | 3685 | if ((flag & FLAG_FORWARD_PROGRESS) || !(flag & FLAG_NOT_DUP)) |
| 3686 | sk_dst_confirm(sk); |
Nandita Dukkipati | 6ba8a3b | 2013-03-11 10:00:43 +0000 | [diff] [blame] | 3687 | |
Yuchung Cheng | a77fa01 | 2018-04-17 23:18:47 -0700 | [diff] [blame] | 3688 | delivered = tcp_newly_delivered(sk, delivered, flag); |
Yuchung Cheng | b9f6482 | 2016-09-19 23:39:14 -0400 | [diff] [blame] | 3689 | lost = tp->lost - lost; /* freshly marked lost */ |
Yuchung Cheng | e428660 | 2018-01-17 12:11:01 -0800 | [diff] [blame] | 3690 | rs.is_ack_delayed = !!(flag & FLAG_ACK_MAYBE_DELAYED); |
Yousuk Seung | d476175 | 2017-12-07 13:41:34 -0800 | [diff] [blame] | 3691 | tcp_rate_gen(sk, delivered, lost, is_sack_reneg, sack_state.rate); |
Yuchung Cheng | deed7be | 2017-01-12 22:11:32 -0800 | [diff] [blame] | 3692 | tcp_cong_control(sk, ack, delivered, flag, sack_state.rate); |
Yuchung Cheng | e662ca4 | 2016-02-02 10:33:04 -0800 | [diff] [blame] | 3693 | tcp_xmit_recovery(sk, rexmit); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3694 | return 1; |
| 3695 | |
| 3696 | no_queue: |
Neal Cardwell | 5628adf | 2011-11-16 08:58:02 +0000 | [diff] [blame] | 3697 | /* If data was DSACKed, see if we can undo a cwnd reduction. */ |
Yuchung Cheng | a77fa01 | 2018-04-17 23:18:47 -0700 | [diff] [blame] | 3698 | if (flag & FLAG_DSACKING_ACK) { |
Eric Dumazet | 19119f2 | 2018-11-27 14:42:01 -0800 | [diff] [blame] | 3699 | tcp_fastretrans_alert(sk, prior_snd_una, num_dupack, &flag, |
Yuchung Cheng | 737ff31 | 2017-11-08 13:01:27 -0800 | [diff] [blame] | 3700 | &rexmit); |
Yuchung Cheng | a77fa01 | 2018-04-17 23:18:47 -0700 | [diff] [blame] | 3701 | tcp_newly_delivered(sk, delivered, flag); |
| 3702 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3703 | /* If this ack opens up a zero window, clear backoff. It was |
| 3704 | * being used to time the probes, and is probably far higher than |
| 3705 | * it needs to be for normal retransmission. |
| 3706 | */ |
Eric Dumazet | 75c119a | 2017-10-05 22:21:27 -0700 | [diff] [blame] | 3707 | tcp_ack_probe(sk); |
Nandita Dukkipati | 9b717a8 | 2013-03-11 10:00:44 +0000 | [diff] [blame] | 3708 | |
| 3709 | if (tp->tlp_high_seq) |
| 3710 | tcp_process_tlp_ack(sk, ack, flag); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3711 | return 1; |
| 3712 | |
| 3713 | old_ack: |
Neal Cardwell | e95ae2f | 2011-11-16 08:58:03 +0000 | [diff] [blame] | 3714 | /* If data was SACKed, tag it and see if we should send more data. |
| 3715 | * If data was DSACKed, see if we can undo a cwnd reduction. |
| 3716 | */ |
Ilpo Järvinen | 8aca6cb | 2008-06-04 11:34:22 -0700 | [diff] [blame] | 3717 | if (TCP_SKB_CB(skb)->sacked) { |
Yuchung Cheng | 59c9af4 | 2013-07-22 16:20:47 -0700 | [diff] [blame] | 3718 | flag |= tcp_sacktag_write_queue(sk, skb, prior_snd_una, |
Kenneth Klette Jonassen | 196da97 | 2015-05-01 01:10:57 +0200 | [diff] [blame] | 3719 | &sack_state); |
Eric Dumazet | 19119f2 | 2018-11-27 14:42:01 -0800 | [diff] [blame] | 3720 | tcp_fastretrans_alert(sk, prior_snd_una, num_dupack, &flag, |
Yuchung Cheng | 737ff31 | 2017-11-08 13:01:27 -0800 | [diff] [blame] | 3721 | &rexmit); |
Yuchung Cheng | a77fa01 | 2018-04-17 23:18:47 -0700 | [diff] [blame] | 3722 | tcp_newly_delivered(sk, delivered, flag); |
Yuchung Cheng | e662ca4 | 2016-02-02 10:33:04 -0800 | [diff] [blame] | 3723 | tcp_xmit_recovery(sk, rexmit); |
Ilpo Järvinen | 8aca6cb | 2008-06-04 11:34:22 -0700 | [diff] [blame] | 3724 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3725 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3726 | return 0; |
| 3727 | } |
| 3728 | |
Daniel Lee | 7f9b838 | 2015-04-06 14:37:26 -0700 | [diff] [blame] | 3729 | static void tcp_parse_fastopen_option(int len, const unsigned char *cookie, |
| 3730 | bool syn, struct tcp_fastopen_cookie *foc, |
| 3731 | bool exp_opt) |
| 3732 | { |
| 3733 | /* Valid only in SYN or SYN-ACK with an even length. */ |
| 3734 | if (!foc || !syn || len < 0 || (len & 1)) |
| 3735 | return; |
| 3736 | |
| 3737 | if (len >= TCP_FASTOPEN_COOKIE_MIN && |
| 3738 | len <= TCP_FASTOPEN_COOKIE_MAX) |
| 3739 | memcpy(foc->val, cookie, len); |
| 3740 | else if (len != 0) |
| 3741 | len = -1; |
| 3742 | foc->len = len; |
| 3743 | foc->exp = exp_opt; |
| 3744 | } |
| 3745 | |
Ursula Braun | 60e2a77 | 2017-10-25 11:01:45 +0200 | [diff] [blame] | 3746 | static void smc_parse_options(const struct tcphdr *th, |
| 3747 | struct tcp_options_received *opt_rx, |
| 3748 | const unsigned char *ptr, |
| 3749 | int opsize) |
| 3750 | { |
| 3751 | #if IS_ENABLED(CONFIG_SMC) |
| 3752 | if (static_branch_unlikely(&tcp_have_smc)) { |
| 3753 | if (th->syn && !(opsize & 1) && |
| 3754 | opsize >= TCPOLEN_EXP_SMC_BASE && |
| 3755 | get_unaligned_be32(ptr) == TCPOPT_SMC_MAGIC) |
| 3756 | opt_rx->smc_ok = 1; |
| 3757 | } |
| 3758 | #endif |
| 3759 | } |
| 3760 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3761 | /* Look for tcp options. Normally only called on SYN and SYNACK packets. |
| 3762 | * But, this can also be called on packets in the established flow when |
| 3763 | * the fast version below fails. |
| 3764 | */ |
Eric Dumazet | eed29f1 | 2017-06-07 10:34:36 -0700 | [diff] [blame] | 3765 | void tcp_parse_options(const struct net *net, |
| 3766 | const struct sk_buff *skb, |
Christoph Paasch | 1a2c618 | 2013-03-17 08:23:34 +0000 | [diff] [blame] | 3767 | struct tcp_options_received *opt_rx, int estab, |
Yuchung Cheng | 2100c8d | 2012-07-19 06:43:05 +0000 | [diff] [blame] | 3768 | struct tcp_fastopen_cookie *foc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3769 | { |
Eric Dumazet | cf533ea | 2011-10-21 05:22:42 -0400 | [diff] [blame] | 3770 | const unsigned char *ptr; |
| 3771 | const struct tcphdr *th = tcp_hdr(skb); |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 3772 | int length = (th->doff * 4) - sizeof(struct tcphdr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3773 | |
Eric Dumazet | cf533ea | 2011-10-21 05:22:42 -0400 | [diff] [blame] | 3774 | ptr = (const unsigned char *)(th + 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3775 | opt_rx->saw_tstamp = 0; |
| 3776 | |
Stephen Hemminger | 2de979b | 2007-03-08 20:45:19 -0800 | [diff] [blame] | 3777 | while (length > 0) { |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 3778 | int opcode = *ptr++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3779 | int opsize; |
| 3780 | |
| 3781 | switch (opcode) { |
Ilpo Järvinen | f038ac8 | 2008-01-03 20:36:55 -0800 | [diff] [blame] | 3782 | case TCPOPT_EOL: |
| 3783 | return; |
| 3784 | case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */ |
| 3785 | length--; |
| 3786 | continue; |
| 3787 | default: |
| 3788 | opsize = *ptr++; |
| 3789 | if (opsize < 2) /* "silly options" */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3790 | return; |
Ilpo Järvinen | f038ac8 | 2008-01-03 20:36:55 -0800 | [diff] [blame] | 3791 | if (opsize > length) |
| 3792 | return; /* don't parse partial options */ |
| 3793 | switch (opcode) { |
| 3794 | case TCPOPT_MSS: |
| 3795 | if (opsize == TCPOLEN_MSS && th->syn && !estab) { |
Harvey Harrison | d3e2ce3 | 2008-05-02 16:26:16 -0700 | [diff] [blame] | 3796 | u16 in_mss = get_unaligned_be16(ptr); |
Ilpo Järvinen | f038ac8 | 2008-01-03 20:36:55 -0800 | [diff] [blame] | 3797 | if (in_mss) { |
| 3798 | if (opt_rx->user_mss && |
| 3799 | opt_rx->user_mss < in_mss) |
| 3800 | in_mss = opt_rx->user_mss; |
| 3801 | opt_rx->mss_clamp = in_mss; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3802 | } |
Stephen Hemminger | 3ff50b7 | 2007-04-20 17:09:22 -0700 | [diff] [blame] | 3803 | } |
Ilpo Järvinen | f038ac8 | 2008-01-03 20:36:55 -0800 | [diff] [blame] | 3804 | break; |
| 3805 | case TCPOPT_WINDOW: |
| 3806 | if (opsize == TCPOLEN_WINDOW && th->syn && |
Eric Dumazet | 9bb37ef | 2017-06-07 10:34:38 -0700 | [diff] [blame] | 3807 | !estab && net->ipv4.sysctl_tcp_window_scaling) { |
Ilpo Järvinen | f038ac8 | 2008-01-03 20:36:55 -0800 | [diff] [blame] | 3808 | __u8 snd_wscale = *(__u8 *)ptr; |
| 3809 | opt_rx->wscale_ok = 1; |
Gao Feng | 589c49c | 2017-04-04 21:09:48 +0800 | [diff] [blame] | 3810 | if (snd_wscale > TCP_MAX_WSCALE) { |
| 3811 | net_info_ratelimited("%s: Illegal window scaling value %d > %u received\n", |
Joe Perches | e87cc47 | 2012-05-13 21:56:26 +0000 | [diff] [blame] | 3812 | __func__, |
Gao Feng | 589c49c | 2017-04-04 21:09:48 +0800 | [diff] [blame] | 3813 | snd_wscale, |
| 3814 | TCP_MAX_WSCALE); |
| 3815 | snd_wscale = TCP_MAX_WSCALE; |
Ilpo Järvinen | f038ac8 | 2008-01-03 20:36:55 -0800 | [diff] [blame] | 3816 | } |
| 3817 | opt_rx->snd_wscale = snd_wscale; |
| 3818 | } |
| 3819 | break; |
| 3820 | case TCPOPT_TIMESTAMP: |
| 3821 | if ((opsize == TCPOLEN_TIMESTAMP) && |
| 3822 | ((estab && opt_rx->tstamp_ok) || |
Eric Dumazet | 5d2ed05 | 2017-06-07 10:34:39 -0700 | [diff] [blame] | 3823 | (!estab && net->ipv4.sysctl_tcp_timestamps))) { |
Ilpo Järvinen | f038ac8 | 2008-01-03 20:36:55 -0800 | [diff] [blame] | 3824 | opt_rx->saw_tstamp = 1; |
Harvey Harrison | d3e2ce3 | 2008-05-02 16:26:16 -0700 | [diff] [blame] | 3825 | opt_rx->rcv_tsval = get_unaligned_be32(ptr); |
| 3826 | opt_rx->rcv_tsecr = get_unaligned_be32(ptr + 4); |
Ilpo Järvinen | f038ac8 | 2008-01-03 20:36:55 -0800 | [diff] [blame] | 3827 | } |
| 3828 | break; |
| 3829 | case TCPOPT_SACK_PERM: |
| 3830 | if (opsize == TCPOLEN_SACK_PERM && th->syn && |
Eric Dumazet | f930103 | 2017-06-07 10:34:37 -0700 | [diff] [blame] | 3831 | !estab && net->ipv4.sysctl_tcp_sack) { |
Vijay Subramanian | ab56222 | 2011-12-20 13:23:24 +0000 | [diff] [blame] | 3832 | opt_rx->sack_ok = TCP_SACK_SEEN; |
Ilpo Järvinen | f038ac8 | 2008-01-03 20:36:55 -0800 | [diff] [blame] | 3833 | tcp_sack_reset(opt_rx); |
| 3834 | } |
| 3835 | break; |
Stephen Hemminger | 3ff50b7 | 2007-04-20 17:09:22 -0700 | [diff] [blame] | 3836 | |
Ilpo Järvinen | f038ac8 | 2008-01-03 20:36:55 -0800 | [diff] [blame] | 3837 | case TCPOPT_SACK: |
| 3838 | if ((opsize >= (TCPOLEN_SACK_BASE + TCPOLEN_SACK_PERBLOCK)) && |
| 3839 | !((opsize - TCPOLEN_SACK_BASE) % TCPOLEN_SACK_PERBLOCK) && |
| 3840 | opt_rx->sack_ok) { |
| 3841 | TCP_SKB_CB(skb)->sacked = (ptr - 2) - (unsigned char *)th; |
| 3842 | } |
| 3843 | break; |
| 3844 | #ifdef CONFIG_TCP_MD5SIG |
| 3845 | case TCPOPT_MD5SIG: |
| 3846 | /* |
| 3847 | * The MD5 Hash has already been |
| 3848 | * checked (see tcp_v{4,6}_do_rcv()). |
| 3849 | */ |
| 3850 | break; |
| 3851 | #endif |
Daniel Lee | 7f9b838 | 2015-04-06 14:37:26 -0700 | [diff] [blame] | 3852 | case TCPOPT_FASTOPEN: |
| 3853 | tcp_parse_fastopen_option( |
| 3854 | opsize - TCPOLEN_FASTOPEN_BASE, |
| 3855 | ptr, th->syn, foc, false); |
| 3856 | break; |
| 3857 | |
Yuchung Cheng | 2100c8d | 2012-07-19 06:43:05 +0000 | [diff] [blame] | 3858 | case TCPOPT_EXP: |
| 3859 | /* Fast Open option shares code 254 using a |
Daniel Lee | 7f9b838 | 2015-04-06 14:37:26 -0700 | [diff] [blame] | 3860 | * 16 bits magic number. |
Yuchung Cheng | 2100c8d | 2012-07-19 06:43:05 +0000 | [diff] [blame] | 3861 | */ |
Daniel Lee | 7f9b838 | 2015-04-06 14:37:26 -0700 | [diff] [blame] | 3862 | if (opsize >= TCPOLEN_EXP_FASTOPEN_BASE && |
| 3863 | get_unaligned_be16(ptr) == |
| 3864 | TCPOPT_FASTOPEN_MAGIC) |
| 3865 | tcp_parse_fastopen_option(opsize - |
| 3866 | TCPOLEN_EXP_FASTOPEN_BASE, |
| 3867 | ptr + 2, th->syn, foc, true); |
Ursula Braun | 60e2a77 | 2017-10-25 11:01:45 +0200 | [diff] [blame] | 3868 | else |
| 3869 | smc_parse_options(th, opt_rx, ptr, |
| 3870 | opsize); |
Yuchung Cheng | 2100c8d | 2012-07-19 06:43:05 +0000 | [diff] [blame] | 3871 | break; |
| 3872 | |
| 3873 | } |
Ilpo Järvinen | f038ac8 | 2008-01-03 20:36:55 -0800 | [diff] [blame] | 3874 | ptr += opsize-2; |
| 3875 | length -= opsize; |
Stephen Hemminger | 3ff50b7 | 2007-04-20 17:09:22 -0700 | [diff] [blame] | 3876 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3877 | } |
| 3878 | } |
Eric Dumazet | 4bc2f18 | 2010-07-09 21:22:10 +0000 | [diff] [blame] | 3879 | EXPORT_SYMBOL(tcp_parse_options); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3880 | |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 3881 | static bool tcp_parse_aligned_timestamp(struct tcp_sock *tp, const struct tcphdr *th) |
Ilpo Järvinen | a4356b2 | 2008-08-23 05:12:29 -0700 | [diff] [blame] | 3882 | { |
Eric Dumazet | cf533ea | 2011-10-21 05:22:42 -0400 | [diff] [blame] | 3883 | const __be32 *ptr = (const __be32 *)(th + 1); |
Ilpo Järvinen | a4356b2 | 2008-08-23 05:12:29 -0700 | [diff] [blame] | 3884 | |
| 3885 | if (*ptr == htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
| 3886 | | (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP)) { |
| 3887 | tp->rx_opt.saw_tstamp = 1; |
| 3888 | ++ptr; |
| 3889 | tp->rx_opt.rcv_tsval = ntohl(*ptr); |
| 3890 | ++ptr; |
Andrew Vagin | e3e1202 | 2013-08-27 12:21:55 +0400 | [diff] [blame] | 3891 | if (*ptr) |
| 3892 | tp->rx_opt.rcv_tsecr = ntohl(*ptr) - tp->tsoffset; |
| 3893 | else |
| 3894 | tp->rx_opt.rcv_tsecr = 0; |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 3895 | return true; |
Ilpo Järvinen | a4356b2 | 2008-08-23 05:12:29 -0700 | [diff] [blame] | 3896 | } |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 3897 | return false; |
Ilpo Järvinen | a4356b2 | 2008-08-23 05:12:29 -0700 | [diff] [blame] | 3898 | } |
| 3899 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3900 | /* Fast parse options. This hopes to only see timestamps. |
| 3901 | * If it is wrong it falls back on tcp_parse_options(). |
| 3902 | */ |
Eric Dumazet | eed29f1 | 2017-06-07 10:34:36 -0700 | [diff] [blame] | 3903 | static bool tcp_fast_parse_options(const struct net *net, |
| 3904 | const struct sk_buff *skb, |
Christoph Paasch | 1a2c618 | 2013-03-17 08:23:34 +0000 | [diff] [blame] | 3905 | const struct tcphdr *th, struct tcp_sock *tp) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3906 | { |
William Allen Simpson | 4957faade | 2009-12-02 18:25:27 +0000 | [diff] [blame] | 3907 | /* In the spirit of fast parsing, compare doff directly to constant |
| 3908 | * values. Because equality is used, short doff can be ignored here. |
| 3909 | */ |
| 3910 | if (th->doff == (sizeof(*th) / 4)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3911 | tp->rx_opt.saw_tstamp = 0; |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 3912 | return false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3913 | } else if (tp->rx_opt.tstamp_ok && |
William Allen Simpson | 4957faade | 2009-12-02 18:25:27 +0000 | [diff] [blame] | 3914 | th->doff == ((sizeof(*th) + TCPOLEN_TSTAMP_ALIGNED) / 4)) { |
Ilpo Järvinen | a4356b2 | 2008-08-23 05:12:29 -0700 | [diff] [blame] | 3915 | if (tcp_parse_aligned_timestamp(tp, th)) |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 3916 | return true; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3917 | } |
Andrey Vagin | ee684b6 | 2013-02-11 05:50:19 +0000 | [diff] [blame] | 3918 | |
Eric Dumazet | eed29f1 | 2017-06-07 10:34:36 -0700 | [diff] [blame] | 3919 | tcp_parse_options(net, skb, &tp->rx_opt, 1, NULL); |
Andrew Vagin | e3e1202 | 2013-08-27 12:21:55 +0400 | [diff] [blame] | 3920 | if (tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr) |
Andrey Vagin | ee684b6 | 2013-02-11 05:50:19 +0000 | [diff] [blame] | 3921 | tp->rx_opt.rcv_tsecr -= tp->tsoffset; |
| 3922 | |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 3923 | return true; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3924 | } |
| 3925 | |
YOSHIFUJI Hideaki | 7d5d552 | 2008-04-17 12:29:53 +0900 | [diff] [blame] | 3926 | #ifdef CONFIG_TCP_MD5SIG |
| 3927 | /* |
| 3928 | * Parse MD5 Signature option |
| 3929 | */ |
Eric Dumazet | cf533ea | 2011-10-21 05:22:42 -0400 | [diff] [blame] | 3930 | const u8 *tcp_parse_md5sig_option(const struct tcphdr *th) |
YOSHIFUJI Hideaki | 7d5d552 | 2008-04-17 12:29:53 +0900 | [diff] [blame] | 3931 | { |
Eric Dumazet | cf533ea | 2011-10-21 05:22:42 -0400 | [diff] [blame] | 3932 | int length = (th->doff << 2) - sizeof(*th); |
| 3933 | const u8 *ptr = (const u8 *)(th + 1); |
YOSHIFUJI Hideaki | 7d5d552 | 2008-04-17 12:29:53 +0900 | [diff] [blame] | 3934 | |
Jann Horn | 7e5a206 | 2018-04-20 15:57:30 +0200 | [diff] [blame] | 3935 | /* If not enough data remaining, we can short cut */ |
| 3936 | while (length >= TCPOLEN_MD5SIG) { |
YOSHIFUJI Hideaki | 7d5d552 | 2008-04-17 12:29:53 +0900 | [diff] [blame] | 3937 | int opcode = *ptr++; |
| 3938 | int opsize; |
| 3939 | |
Weilong Chen | a22318e | 2013-12-23 14:37:26 +0800 | [diff] [blame] | 3940 | switch (opcode) { |
YOSHIFUJI Hideaki | 7d5d552 | 2008-04-17 12:29:53 +0900 | [diff] [blame] | 3941 | case TCPOPT_EOL: |
| 3942 | return NULL; |
| 3943 | case TCPOPT_NOP: |
| 3944 | length--; |
| 3945 | continue; |
| 3946 | default: |
| 3947 | opsize = *ptr++; |
| 3948 | if (opsize < 2 || opsize > length) |
| 3949 | return NULL; |
| 3950 | if (opcode == TCPOPT_MD5SIG) |
Dmitry Popov | ba78e2d | 2010-08-07 20:24:28 -0700 | [diff] [blame] | 3951 | return opsize == TCPOLEN_MD5SIG ? ptr : NULL; |
YOSHIFUJI Hideaki | 7d5d552 | 2008-04-17 12:29:53 +0900 | [diff] [blame] | 3952 | } |
| 3953 | ptr += opsize - 2; |
| 3954 | length -= opsize; |
| 3955 | } |
| 3956 | return NULL; |
| 3957 | } |
Eric Dumazet | 4bc2f18 | 2010-07-09 21:22:10 +0000 | [diff] [blame] | 3958 | EXPORT_SYMBOL(tcp_parse_md5sig_option); |
YOSHIFUJI Hideaki | 7d5d552 | 2008-04-17 12:29:53 +0900 | [diff] [blame] | 3959 | #endif |
| 3960 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3961 | /* Sorry, PAWS as specified is broken wrt. pure-ACKs -DaveM |
| 3962 | * |
| 3963 | * It is not fatal. If this ACK does _not_ change critical state (seqs, window) |
| 3964 | * it can pass through stack. So, the following predicate verifies that |
| 3965 | * this segment is not used for anything but congestion avoidance or |
| 3966 | * fast retransmit. Moreover, we even are able to eliminate most of such |
| 3967 | * second order effects, if we apply some small "replay" window (~RTO) |
| 3968 | * to timestamp space. |
| 3969 | * |
| 3970 | * All these measures still do not guarantee that we reject wrapped ACKs |
| 3971 | * on networks with high bandwidth, when sequence space is recycled fastly, |
| 3972 | * but it guarantees that such events will be very rare and do not affect |
| 3973 | * connection seriously. This doesn't look nice, but alas, PAWS is really |
| 3974 | * buggy extension. |
| 3975 | * |
| 3976 | * [ Later note. Even worse! It is buggy for segments _with_ data. RFC |
| 3977 | * states that events when retransmit arrives after original data are rare. |
| 3978 | * It is a blatant lie. VJ forgot about fast retransmit! 8)8) It is |
| 3979 | * the biggest problem on large power networks even with minor reordering. |
| 3980 | * OK, let's give it small replay window. If peer clock is even 1hz, it is safe |
| 3981 | * up to bandwidth of 18Gigabit/sec. 8) ] |
| 3982 | */ |
| 3983 | |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 3984 | static int tcp_disordered_ack(const struct sock *sk, const struct sk_buff *skb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3985 | { |
Eric Dumazet | cf533ea | 2011-10-21 05:22:42 -0400 | [diff] [blame] | 3986 | const struct tcp_sock *tp = tcp_sk(sk); |
| 3987 | const struct tcphdr *th = tcp_hdr(skb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3988 | u32 seq = TCP_SKB_CB(skb)->seq; |
| 3989 | u32 ack = TCP_SKB_CB(skb)->ack_seq; |
| 3990 | |
| 3991 | return (/* 1. Pure ACK with correct sequence number. */ |
| 3992 | (th->ack && seq == TCP_SKB_CB(skb)->end_seq && seq == tp->rcv_nxt) && |
| 3993 | |
| 3994 | /* 2. ... and duplicate ACK. */ |
| 3995 | ack == tp->snd_una && |
| 3996 | |
| 3997 | /* 3. ... and does not update window. */ |
| 3998 | !tcp_may_update_window(tp, ack, seq, ntohs(th->window) << tp->rx_opt.snd_wscale) && |
| 3999 | |
| 4000 | /* 4. ... and sits in replay window. */ |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 4001 | (s32)(tp->rx_opt.ts_recent - tp->rx_opt.rcv_tsval) <= (inet_csk(sk)->icsk_rto * 1024) / HZ); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4002 | } |
| 4003 | |
Vijay Subramanian | 67b95bd | 2012-07-19 21:32:18 +0000 | [diff] [blame] | 4004 | static inline bool tcp_paws_discard(const struct sock *sk, |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 4005 | const struct sk_buff *skb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4006 | { |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 4007 | const struct tcp_sock *tp = tcp_sk(sk); |
Ilpo Järvinen | c887e6d | 2009-03-14 14:23:03 +0000 | [diff] [blame] | 4008 | |
| 4009 | return !tcp_paws_check(&tp->rx_opt, TCP_PAWS_WINDOW) && |
| 4010 | !tcp_disordered_ack(sk, skb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4011 | } |
| 4012 | |
| 4013 | /* Check segment sequence number for validity. |
| 4014 | * |
| 4015 | * Segment controls are considered valid, if the segment |
| 4016 | * fits to the window after truncation to the window. Acceptability |
| 4017 | * of data (and SYN, FIN, of course) is checked separately. |
| 4018 | * See tcp_data_queue(), for example. |
| 4019 | * |
| 4020 | * Also, controls (RST is main one) are accepted using RCV.WUP instead |
| 4021 | * of RCV.NXT. Peer still did not advance his SND.UNA when we |
| 4022 | * delayed ACK, so that hisSND.UNA<=ourRCV.WUP. |
| 4023 | * (borrowed from freebsd) |
| 4024 | */ |
| 4025 | |
Vijay Subramanian | 67b95bd | 2012-07-19 21:32:18 +0000 | [diff] [blame] | 4026 | static inline bool tcp_sequence(const struct tcp_sock *tp, u32 seq, u32 end_seq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4027 | { |
| 4028 | return !before(end_seq, tp->rcv_wup) && |
| 4029 | !after(seq, tp->rcv_nxt + tcp_receive_window(tp)); |
| 4030 | } |
| 4031 | |
| 4032 | /* When we get a reset we do this. */ |
Jerry Chu | 1046716 | 2012-08-31 12:29:11 +0000 | [diff] [blame] | 4033 | void tcp_reset(struct sock *sk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4034 | { |
Song Liu | 5941521 | 2017-10-23 09:20:25 -0700 | [diff] [blame] | 4035 | trace_tcp_receive_reset(sk); |
| 4036 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4037 | /* We want the right error as BSD sees it (and indeed as we do). */ |
| 4038 | switch (sk->sk_state) { |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 4039 | case TCP_SYN_SENT: |
| 4040 | sk->sk_err = ECONNREFUSED; |
| 4041 | break; |
| 4042 | case TCP_CLOSE_WAIT: |
| 4043 | sk->sk_err = EPIPE; |
| 4044 | break; |
| 4045 | case TCP_CLOSE: |
| 4046 | return; |
| 4047 | default: |
| 4048 | sk->sk_err = ECONNRESET; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4049 | } |
Tom Marshall | a4d2580 | 2010-09-20 15:42:05 -0700 | [diff] [blame] | 4050 | /* This barrier is coupled with smp_rmb() in tcp_poll() */ |
| 4051 | smp_wmb(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4052 | |
Soheil Hassas Yeganeh | a27fd7a | 2018-02-27 18:32:18 -0500 | [diff] [blame] | 4053 | tcp_write_queue_purge(sk); |
Eric Dumazet | 3d47626 | 2017-04-18 09:45:51 -0700 | [diff] [blame] | 4054 | tcp_done(sk); |
| 4055 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4056 | if (!sock_flag(sk, SOCK_DEAD)) |
| 4057 | sk->sk_error_report(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4058 | } |
| 4059 | |
| 4060 | /* |
| 4061 | * Process the FIN bit. This now behaves as it is supposed to work |
| 4062 | * and the FIN takes effect when it is validly part of sequence |
| 4063 | * space. Not before when we get holes. |
| 4064 | * |
| 4065 | * If we are ESTABLISHED, a received fin moves us to CLOSE-WAIT |
| 4066 | * (and thence onto LAST-ACK and finally, CLOSE, we never enter |
| 4067 | * TIME-WAIT) |
| 4068 | * |
| 4069 | * If we are in FINWAIT-1, a received FIN indicates simultaneous |
| 4070 | * close and we go into CLOSING (and later onto TIME-WAIT) |
| 4071 | * |
| 4072 | * If we are in FINWAIT-2, a received FIN moves us to TIME-WAIT. |
| 4073 | */ |
Eric Dumazet | e3e17b7 | 2016-02-06 11:16:28 -0800 | [diff] [blame] | 4074 | void tcp_fin(struct sock *sk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4075 | { |
| 4076 | struct tcp_sock *tp = tcp_sk(sk); |
| 4077 | |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 4078 | inet_csk_schedule_ack(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4079 | |
| 4080 | sk->sk_shutdown |= RCV_SHUTDOWN; |
| 4081 | sock_set_flag(sk, SOCK_DONE); |
| 4082 | |
| 4083 | switch (sk->sk_state) { |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 4084 | case TCP_SYN_RECV: |
| 4085 | case TCP_ESTABLISHED: |
| 4086 | /* Move to CLOSE_WAIT */ |
| 4087 | tcp_set_state(sk, TCP_CLOSE_WAIT); |
Wei Wang | 31954cd | 2019-01-25 10:53:19 -0800 | [diff] [blame] | 4088 | inet_csk_enter_pingpong_mode(sk); |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 4089 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4090 | |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 4091 | case TCP_CLOSE_WAIT: |
| 4092 | case TCP_CLOSING: |
| 4093 | /* Received a retransmission of the FIN, do |
| 4094 | * nothing. |
| 4095 | */ |
| 4096 | break; |
| 4097 | case TCP_LAST_ACK: |
| 4098 | /* RFC793: Remain in the LAST-ACK state. */ |
| 4099 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4100 | |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 4101 | case TCP_FIN_WAIT1: |
| 4102 | /* This case occurs when a simultaneous close |
| 4103 | * happens, we must ack the received FIN and |
| 4104 | * enter the CLOSING state. |
| 4105 | */ |
| 4106 | tcp_send_ack(sk); |
| 4107 | tcp_set_state(sk, TCP_CLOSING); |
| 4108 | break; |
| 4109 | case TCP_FIN_WAIT2: |
| 4110 | /* Received a FIN -- send ACK and enter TIME_WAIT. */ |
| 4111 | tcp_send_ack(sk); |
| 4112 | tcp_time_wait(sk, TCP_TIME_WAIT, 0); |
| 4113 | break; |
| 4114 | default: |
| 4115 | /* Only TCP_LISTEN and TCP_CLOSE are left, in these |
| 4116 | * cases we should never reach this piece of code. |
| 4117 | */ |
Joe Perches | 058bd4d | 2012-03-11 18:36:11 +0000 | [diff] [blame] | 4118 | pr_err("%s: Impossible, sk->sk_state=%d\n", |
Harvey Harrison | 0dc4787 | 2008-03-05 20:47:47 -0800 | [diff] [blame] | 4119 | __func__, sk->sk_state); |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 4120 | break; |
Stephen Hemminger | 3ff50b7 | 2007-04-20 17:09:22 -0700 | [diff] [blame] | 4121 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4122 | |
| 4123 | /* It _is_ possible, that we have something out-of-order _after_ FIN. |
| 4124 | * Probably, we should reset in this case. For now drop them. |
| 4125 | */ |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4126 | skb_rbtree_purge(&tp->out_of_order_queue); |
Ilpo Järvinen | e60402d | 2007-08-09 15:14:46 +0300 | [diff] [blame] | 4127 | if (tcp_is_sack(tp)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4128 | tcp_sack_reset(&tp->rx_opt); |
Hideo Aoki | 3ab224b | 2007-12-31 00:11:19 -0800 | [diff] [blame] | 4129 | sk_mem_reclaim(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4130 | |
| 4131 | if (!sock_flag(sk, SOCK_DEAD)) { |
| 4132 | sk->sk_state_change(sk); |
| 4133 | |
| 4134 | /* Do not send POLL_HUP for half duplex close. */ |
| 4135 | if (sk->sk_shutdown == SHUTDOWN_MASK || |
| 4136 | sk->sk_state == TCP_CLOSE) |
Pavel Emelyanov | 8d8ad9d | 2007-11-26 20:10:50 +0800 | [diff] [blame] | 4137 | sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4138 | else |
Pavel Emelyanov | 8d8ad9d | 2007-11-26 20:10:50 +0800 | [diff] [blame] | 4139 | sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4140 | } |
| 4141 | } |
| 4142 | |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 4143 | static inline bool tcp_sack_extend(struct tcp_sack_block *sp, u32 seq, |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 4144 | u32 end_seq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4145 | { |
| 4146 | if (!after(seq, sp->end_seq) && !after(sp->start_seq, end_seq)) { |
| 4147 | if (before(seq, sp->start_seq)) |
| 4148 | sp->start_seq = seq; |
| 4149 | if (after(end_seq, sp->end_seq)) |
| 4150 | sp->end_seq = end_seq; |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 4151 | return true; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4152 | } |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 4153 | return false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4154 | } |
| 4155 | |
Pavel Emelyanov | 1ed8346 | 2008-07-16 20:29:51 -0700 | [diff] [blame] | 4156 | static void tcp_dsack_set(struct sock *sk, u32 seq, u32 end_seq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4157 | { |
Pavel Emelyanov | 1ed8346 | 2008-07-16 20:29:51 -0700 | [diff] [blame] | 4158 | struct tcp_sock *tp = tcp_sk(sk); |
| 4159 | |
Eric Dumazet | 6496f6b | 2017-10-26 21:55:07 -0700 | [diff] [blame] | 4160 | if (tcp_is_sack(tp) && sock_net(sk)->ipv4.sysctl_tcp_dsack) { |
Pavel Emelyanov | 40b215e | 2008-07-03 01:05:41 -0700 | [diff] [blame] | 4161 | int mib_idx; |
| 4162 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4163 | if (before(seq, tp->rcv_nxt)) |
Pavel Emelyanov | 40b215e | 2008-07-03 01:05:41 -0700 | [diff] [blame] | 4164 | mib_idx = LINUX_MIB_TCPDSACKOLDSENT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4165 | else |
Pavel Emelyanov | 40b215e | 2008-07-03 01:05:41 -0700 | [diff] [blame] | 4166 | mib_idx = LINUX_MIB_TCPDSACKOFOSENT; |
| 4167 | |
Eric Dumazet | c10d931 | 2016-04-29 14:16:47 -0700 | [diff] [blame] | 4168 | NET_INC_STATS(sock_net(sk), mib_idx); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4169 | |
| 4170 | tp->rx_opt.dsack = 1; |
| 4171 | tp->duplicate_sack[0].start_seq = seq; |
| 4172 | tp->duplicate_sack[0].end_seq = end_seq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4173 | } |
| 4174 | } |
| 4175 | |
Pavel Emelyanov | 1ed8346 | 2008-07-16 20:29:51 -0700 | [diff] [blame] | 4176 | static void tcp_dsack_extend(struct sock *sk, u32 seq, u32 end_seq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4177 | { |
Pavel Emelyanov | 1ed8346 | 2008-07-16 20:29:51 -0700 | [diff] [blame] | 4178 | struct tcp_sock *tp = tcp_sk(sk); |
| 4179 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4180 | if (!tp->rx_opt.dsack) |
Pavel Emelyanov | 1ed8346 | 2008-07-16 20:29:51 -0700 | [diff] [blame] | 4181 | tcp_dsack_set(sk, seq, end_seq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4182 | else |
| 4183 | tcp_sack_extend(tp->duplicate_sack, seq, end_seq); |
| 4184 | } |
| 4185 | |
Yuchung Cheng | 7788174 | 2018-08-29 14:53:56 -0700 | [diff] [blame] | 4186 | static void tcp_rcv_spurious_retrans(struct sock *sk, const struct sk_buff *skb) |
| 4187 | { |
| 4188 | /* When the ACK path fails or drops most ACKs, the sender would |
| 4189 | * timeout and spuriously retransmit the same segment repeatedly. |
| 4190 | * The receiver remembers and reflects via DSACKs. Leverage the |
| 4191 | * DSACK state and change the txhash to re-route speculatively. |
| 4192 | */ |
| 4193 | if (TCP_SKB_CB(skb)->seq == tcp_sk(sk)->duplicate_sack[0].start_seq) |
| 4194 | sk_rethink_txhash(sk); |
| 4195 | } |
| 4196 | |
Eric Dumazet | cf533ea | 2011-10-21 05:22:42 -0400 | [diff] [blame] | 4197 | static void tcp_send_dupack(struct sock *sk, const struct sk_buff *skb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4198 | { |
| 4199 | struct tcp_sock *tp = tcp_sk(sk); |
| 4200 | |
| 4201 | if (TCP_SKB_CB(skb)->end_seq != TCP_SKB_CB(skb)->seq && |
| 4202 | before(TCP_SKB_CB(skb)->seq, tp->rcv_nxt)) { |
Eric Dumazet | c10d931 | 2016-04-29 14:16:47 -0700 | [diff] [blame] | 4203 | NET_INC_STATS(sock_net(sk), LINUX_MIB_DELAYEDACKLOST); |
Eric Dumazet | 9a9c9b5 | 2018-05-21 15:08:56 -0700 | [diff] [blame] | 4204 | tcp_enter_quickack_mode(sk, TCP_MAX_QUICKACKS); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4205 | |
Eric Dumazet | 6496f6b | 2017-10-26 21:55:07 -0700 | [diff] [blame] | 4206 | if (tcp_is_sack(tp) && sock_net(sk)->ipv4.sysctl_tcp_dsack) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4207 | u32 end_seq = TCP_SKB_CB(skb)->end_seq; |
| 4208 | |
Yuchung Cheng | 7788174 | 2018-08-29 14:53:56 -0700 | [diff] [blame] | 4209 | tcp_rcv_spurious_retrans(sk, skb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4210 | if (after(TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt)) |
| 4211 | end_seq = tp->rcv_nxt; |
Pavel Emelyanov | 1ed8346 | 2008-07-16 20:29:51 -0700 | [diff] [blame] | 4212 | tcp_dsack_set(sk, TCP_SKB_CB(skb)->seq, end_seq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4213 | } |
| 4214 | } |
| 4215 | |
| 4216 | tcp_send_ack(sk); |
| 4217 | } |
| 4218 | |
| 4219 | /* These routines update the SACK block as out-of-order packets arrive or |
| 4220 | * in-order packets close up the sequence space. |
| 4221 | */ |
| 4222 | static void tcp_sack_maybe_coalesce(struct tcp_sock *tp) |
| 4223 | { |
| 4224 | int this_sack; |
| 4225 | struct tcp_sack_block *sp = &tp->selective_acks[0]; |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 4226 | struct tcp_sack_block *swalk = sp + 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4227 | |
| 4228 | /* See if the recent change to the first SACK eats into |
| 4229 | * or hits the sequence space of other SACK blocks, if so coalesce. |
| 4230 | */ |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 4231 | for (this_sack = 1; this_sack < tp->rx_opt.num_sacks;) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4232 | if (tcp_sack_extend(sp, swalk->start_seq, swalk->end_seq)) { |
| 4233 | int i; |
| 4234 | |
| 4235 | /* Zap SWALK, by moving every further SACK up by one slot. |
| 4236 | * Decrease num_sacks. |
| 4237 | */ |
| 4238 | tp->rx_opt.num_sacks--; |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 4239 | for (i = this_sack; i < tp->rx_opt.num_sacks; i++) |
| 4240 | sp[i] = sp[i + 1]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4241 | continue; |
| 4242 | } |
| 4243 | this_sack++, swalk++; |
| 4244 | } |
| 4245 | } |
| 4246 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4247 | static void tcp_sack_new_ofo_skb(struct sock *sk, u32 seq, u32 end_seq) |
| 4248 | { |
| 4249 | struct tcp_sock *tp = tcp_sk(sk); |
| 4250 | struct tcp_sack_block *sp = &tp->selective_acks[0]; |
| 4251 | int cur_sacks = tp->rx_opt.num_sacks; |
| 4252 | int this_sack; |
| 4253 | |
| 4254 | if (!cur_sacks) |
| 4255 | goto new_sack; |
| 4256 | |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 4257 | for (this_sack = 0; this_sack < cur_sacks; this_sack++, sp++) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4258 | if (tcp_sack_extend(sp, seq, end_seq)) { |
| 4259 | /* Rotate this_sack to the first one. */ |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 4260 | for (; this_sack > 0; this_sack--, sp--) |
Ilpo Järvinen | a0bffff | 2009-03-21 13:36:17 -0700 | [diff] [blame] | 4261 | swap(*sp, *(sp - 1)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4262 | if (cur_sacks > 1) |
| 4263 | tcp_sack_maybe_coalesce(tp); |
| 4264 | return; |
| 4265 | } |
| 4266 | } |
| 4267 | |
| 4268 | /* Could not find an adjacent existing SACK, build a new one, |
| 4269 | * put it at the front, and shift everyone else down. We |
| 4270 | * always know there is at least one SACK present already here. |
| 4271 | * |
| 4272 | * If the sack array is full, forget about the last one. |
| 4273 | */ |
Adam Langley | 4389dde | 2008-07-19 00:07:02 -0700 | [diff] [blame] | 4274 | if (this_sack >= TCP_NUM_SACKS) { |
Eric Dumazet | 86de592 | 2018-11-20 05:53:59 -0800 | [diff] [blame] | 4275 | if (tp->compressed_ack > TCP_FASTRETRANS_THRESH) |
Eric Dumazet | 5d9f426 | 2018-05-17 14:47:26 -0700 | [diff] [blame] | 4276 | tcp_send_ack(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4277 | this_sack--; |
| 4278 | tp->rx_opt.num_sacks--; |
| 4279 | sp--; |
| 4280 | } |
Stephen Hemminger | 2de979b | 2007-03-08 20:45:19 -0800 | [diff] [blame] | 4281 | for (; this_sack > 0; this_sack--, sp--) |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 4282 | *sp = *(sp - 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4283 | |
| 4284 | new_sack: |
| 4285 | /* Build the new head SACK, and we're done. */ |
| 4286 | sp->start_seq = seq; |
| 4287 | sp->end_seq = end_seq; |
| 4288 | tp->rx_opt.num_sacks++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4289 | } |
| 4290 | |
| 4291 | /* RCV.NXT advances, some SACKs should be eaten. */ |
| 4292 | |
| 4293 | static void tcp_sack_remove(struct tcp_sock *tp) |
| 4294 | { |
| 4295 | struct tcp_sack_block *sp = &tp->selective_acks[0]; |
| 4296 | int num_sacks = tp->rx_opt.num_sacks; |
| 4297 | int this_sack; |
| 4298 | |
| 4299 | /* Empty ofo queue, hence, all the SACKs are eaten. Clear. */ |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4300 | if (RB_EMPTY_ROOT(&tp->out_of_order_queue)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4301 | tp->rx_opt.num_sacks = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4302 | return; |
| 4303 | } |
| 4304 | |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 4305 | for (this_sack = 0; this_sack < num_sacks;) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4306 | /* Check if the start of the sack is covered by RCV.NXT. */ |
| 4307 | if (!before(tp->rcv_nxt, sp->start_seq)) { |
| 4308 | int i; |
| 4309 | |
| 4310 | /* RCV.NXT must cover all the block! */ |
Ilpo Järvinen | 547b792 | 2008-07-25 21:43:18 -0700 | [diff] [blame] | 4311 | WARN_ON(before(tp->rcv_nxt, sp->end_seq)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4312 | |
| 4313 | /* Zap this SACK, by moving forward any other SACKS. */ |
Weilong Chen | a22318e | 2013-12-23 14:37:26 +0800 | [diff] [blame] | 4314 | for (i = this_sack+1; i < num_sacks; i++) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4315 | tp->selective_acks[i-1] = tp->selective_acks[i]; |
| 4316 | num_sacks--; |
| 4317 | continue; |
| 4318 | } |
| 4319 | this_sack++; |
| 4320 | sp++; |
| 4321 | } |
Ilpo Järvinen | 5861f8e | 2009-03-14 14:23:01 +0000 | [diff] [blame] | 4322 | tp->rx_opt.num_sacks = num_sacks; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4323 | } |
| 4324 | |
Eric Dumazet | 1402d36 | 2012-04-23 07:11:42 +0000 | [diff] [blame] | 4325 | /** |
| 4326 | * tcp_try_coalesce - try to merge skb to prior one |
| 4327 | * @sk: socket |
Mike Maloney | 98aaa91 | 2017-08-22 17:08:48 -0400 | [diff] [blame] | 4328 | * @dest: destination queue |
Eric Dumazet | 1402d36 | 2012-04-23 07:11:42 +0000 | [diff] [blame] | 4329 | * @to: prior buffer |
| 4330 | * @from: buffer to add in queue |
Eric Dumazet | 923dd34 | 2012-05-02 07:55:58 +0000 | [diff] [blame] | 4331 | * @fragstolen: pointer to boolean |
Eric Dumazet | 1402d36 | 2012-04-23 07:11:42 +0000 | [diff] [blame] | 4332 | * |
| 4333 | * Before queueing skb @from after @to, try to merge them |
| 4334 | * to reduce overall memory use and queue lengths, if cost is small. |
| 4335 | * Packets in ofo or receive queues can stay a long time. |
| 4336 | * Better try to coalesce them right now to avoid future collapses. |
Eric Dumazet | 783c175 | 2012-04-23 17:34:36 +0000 | [diff] [blame] | 4337 | * Returns true if caller should free @from instead of queueing it |
Eric Dumazet | 1402d36 | 2012-04-23 07:11:42 +0000 | [diff] [blame] | 4338 | */ |
Eric Dumazet | 783c175 | 2012-04-23 17:34:36 +0000 | [diff] [blame] | 4339 | static bool tcp_try_coalesce(struct sock *sk, |
| 4340 | struct sk_buff *to, |
Eric Dumazet | 329033f | 2012-04-27 00:38:33 +0000 | [diff] [blame] | 4341 | struct sk_buff *from, |
| 4342 | bool *fragstolen) |
Eric Dumazet | 1402d36 | 2012-04-23 07:11:42 +0000 | [diff] [blame] | 4343 | { |
Eric Dumazet | bad43ca | 2012-05-19 03:02:02 +0000 | [diff] [blame] | 4344 | int delta; |
Eric Dumazet | 1402d36 | 2012-04-23 07:11:42 +0000 | [diff] [blame] | 4345 | |
Eric Dumazet | 329033f | 2012-04-27 00:38:33 +0000 | [diff] [blame] | 4346 | *fragstolen = false; |
Alexander Duyck | 34a802a | 2012-05-02 21:19:09 +0000 | [diff] [blame] | 4347 | |
Eric Dumazet | 1ca7ee3 | 2012-05-23 17:51:37 +0000 | [diff] [blame] | 4348 | /* Its possible this segment overlaps with prior segment in queue */ |
| 4349 | if (TCP_SKB_CB(from)->seq != TCP_SKB_CB(to)->end_seq) |
| 4350 | return false; |
| 4351 | |
Boris Pismenny | 41ed9c0 | 2018-07-13 14:33:38 +0300 | [diff] [blame] | 4352 | #ifdef CONFIG_TLS_DEVICE |
| 4353 | if (from->decrypted != to->decrypted) |
| 4354 | return false; |
| 4355 | #endif |
| 4356 | |
Eric Dumazet | bad43ca | 2012-05-19 03:02:02 +0000 | [diff] [blame] | 4357 | if (!skb_try_coalesce(to, from, fragstolen, &delta)) |
Eric Dumazet | 783c175 | 2012-04-23 17:34:36 +0000 | [diff] [blame] | 4358 | return false; |
Alexander Duyck | 34a802a | 2012-05-02 21:19:09 +0000 | [diff] [blame] | 4359 | |
Alexander Duyck | 34a802a | 2012-05-02 21:19:09 +0000 | [diff] [blame] | 4360 | atomic_add(delta, &sk->sk_rmem_alloc); |
| 4361 | sk_mem_charge(sk, delta); |
Eric Dumazet | c10d931 | 2016-04-29 14:16:47 -0700 | [diff] [blame] | 4362 | NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPRCVCOALESCE); |
Alexander Duyck | 34a802a | 2012-05-02 21:19:09 +0000 | [diff] [blame] | 4363 | TCP_SKB_CB(to)->end_seq = TCP_SKB_CB(from)->end_seq; |
| 4364 | TCP_SKB_CB(to)->ack_seq = TCP_SKB_CB(from)->ack_seq; |
Eric Dumazet | e93a043 | 2014-09-15 04:19:52 -0700 | [diff] [blame] | 4365 | TCP_SKB_CB(to)->tcp_flags |= TCP_SKB_CB(from)->tcp_flags; |
Mike Maloney | 98aaa91 | 2017-08-22 17:08:48 -0400 | [diff] [blame] | 4366 | |
| 4367 | if (TCP_SKB_CB(from)->has_rxtstamp) { |
| 4368 | TCP_SKB_CB(to)->has_rxtstamp = true; |
Eric Dumazet | bffa72c | 2017-09-19 05:14:24 -0700 | [diff] [blame] | 4369 | to->tstamp = from->tstamp; |
Stephen Mallon | cadf9df | 2018-11-20 19:15:02 +1100 | [diff] [blame] | 4370 | skb_hwtstamps(to)->hwtstamp = skb_hwtstamps(from)->hwtstamp; |
Mike Maloney | 98aaa91 | 2017-08-22 17:08:48 -0400 | [diff] [blame] | 4371 | } |
| 4372 | |
Alexander Duyck | 34a802a | 2012-05-02 21:19:09 +0000 | [diff] [blame] | 4373 | return true; |
Eric Dumazet | 1402d36 | 2012-04-23 07:11:42 +0000 | [diff] [blame] | 4374 | } |
| 4375 | |
Eric Dumazet | 58152ec | 2018-07-23 09:28:21 -0700 | [diff] [blame] | 4376 | static bool tcp_ooo_try_coalesce(struct sock *sk, |
| 4377 | struct sk_buff *to, |
| 4378 | struct sk_buff *from, |
| 4379 | bool *fragstolen) |
| 4380 | { |
| 4381 | bool res = tcp_try_coalesce(sk, to, from, fragstolen); |
| 4382 | |
| 4383 | /* In case tcp_drop() is called later, update to->gso_segs */ |
| 4384 | if (res) { |
| 4385 | u32 gso_segs = max_t(u16, 1, skb_shinfo(to)->gso_segs) + |
| 4386 | max_t(u16, 1, skb_shinfo(from)->gso_segs); |
| 4387 | |
| 4388 | skb_shinfo(to)->gso_segs = min_t(u32, gso_segs, 0xFFFF); |
| 4389 | } |
| 4390 | return res; |
| 4391 | } |
| 4392 | |
Eric Dumazet | 532182c | 2016-04-01 08:52:19 -0700 | [diff] [blame] | 4393 | static void tcp_drop(struct sock *sk, struct sk_buff *skb) |
| 4394 | { |
| 4395 | sk_drops_add(sk, skb); |
| 4396 | __kfree_skb(skb); |
| 4397 | } |
| 4398 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4399 | /* This one checks to see if we can put data from the |
| 4400 | * out_of_order queue into the receive_queue. |
| 4401 | */ |
| 4402 | static void tcp_ofo_queue(struct sock *sk) |
| 4403 | { |
| 4404 | struct tcp_sock *tp = tcp_sk(sk); |
| 4405 | __u32 dsack_high = tp->rcv_nxt; |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4406 | bool fin, fragstolen, eaten; |
Eric Dumazet | bd1e75a | 2014-09-19 08:26:20 -0700 | [diff] [blame] | 4407 | struct sk_buff *skb, *tail; |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4408 | struct rb_node *p; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4409 | |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4410 | p = rb_first(&tp->out_of_order_queue); |
| 4411 | while (p) { |
Eric Dumazet | 18a4c0e | 2017-10-05 22:21:21 -0700 | [diff] [blame] | 4412 | skb = rb_to_skb(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4413 | if (after(TCP_SKB_CB(skb)->seq, tp->rcv_nxt)) |
| 4414 | break; |
| 4415 | |
| 4416 | if (before(TCP_SKB_CB(skb)->seq, dsack_high)) { |
| 4417 | __u32 dsack = dsack_high; |
| 4418 | if (before(TCP_SKB_CB(skb)->end_seq, dsack_high)) |
| 4419 | dsack_high = TCP_SKB_CB(skb)->end_seq; |
| 4420 | tcp_dsack_extend(sk, TCP_SKB_CB(skb)->seq, dsack); |
| 4421 | } |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4422 | p = rb_next(p); |
| 4423 | rb_erase(&skb->rbnode, &tp->out_of_order_queue); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4424 | |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4425 | if (unlikely(!after(TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt))) { |
Eric Dumazet | 532182c | 2016-04-01 08:52:19 -0700 | [diff] [blame] | 4426 | tcp_drop(sk, skb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4427 | continue; |
| 4428 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4429 | |
Eric Dumazet | bd1e75a | 2014-09-19 08:26:20 -0700 | [diff] [blame] | 4430 | tail = skb_peek_tail(&sk->sk_receive_queue); |
Eric Dumazet | bffa72c | 2017-09-19 05:14:24 -0700 | [diff] [blame] | 4431 | eaten = tail && tcp_try_coalesce(sk, tail, skb, &fragstolen); |
Eric Dumazet | bdd1f9e | 2015-04-28 15:28:18 -0700 | [diff] [blame] | 4432 | tcp_rcv_nxt_update(tp, TCP_SKB_CB(skb)->end_seq); |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4433 | fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN; |
Eric Dumazet | bd1e75a | 2014-09-19 08:26:20 -0700 | [diff] [blame] | 4434 | if (!eaten) |
| 4435 | __skb_queue_tail(&sk->sk_receive_queue, skb); |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4436 | else |
Eric Dumazet | bd1e75a | 2014-09-19 08:26:20 -0700 | [diff] [blame] | 4437 | kfree_skb_partial(skb, fragstolen); |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4438 | |
| 4439 | if (unlikely(fin)) { |
| 4440 | tcp_fin(sk); |
| 4441 | /* tcp_fin() purges tp->out_of_order_queue, |
| 4442 | * so we must end this loop right now. |
| 4443 | */ |
| 4444 | break; |
| 4445 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4446 | } |
| 4447 | } |
| 4448 | |
| 4449 | static bool tcp_prune_ofo_queue(struct sock *sk); |
| 4450 | static int tcp_prune_queue(struct sock *sk); |
| 4451 | |
| 4452 | static int tcp_try_rmem_schedule(struct sock *sk, struct sk_buff *skb, |
| 4453 | unsigned int size) |
| 4454 | { |
| 4455 | if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf || |
| 4456 | !sk_rmem_schedule(sk, skb, size)) { |
| 4457 | |
| 4458 | if (tcp_prune_queue(sk) < 0) |
| 4459 | return -1; |
Pavel Emelyanov | 1ed8346 | 2008-07-16 20:29:51 -0700 | [diff] [blame] | 4460 | |
Eric Dumazet | 36a6503 | 2016-08-17 14:17:09 -0700 | [diff] [blame] | 4461 | while (!sk_rmem_schedule(sk, skb, size)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4462 | if (!tcp_prune_ofo_queue(sk)) |
| 4463 | return -1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4464 | } |
| 4465 | } |
| 4466 | return 0; |
| 4467 | } |
| 4468 | |
Eric Dumazet | e86b2919 | 2012-03-18 11:06:44 +0000 | [diff] [blame] | 4469 | static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb) |
| 4470 | { |
| 4471 | struct tcp_sock *tp = tcp_sk(sk); |
Eric Dumazet | 18a4c0e | 2017-10-05 22:21:21 -0700 | [diff] [blame] | 4472 | struct rb_node **p, *parent; |
Eric Dumazet | e86b2919 | 2012-03-18 11:06:44 +0000 | [diff] [blame] | 4473 | struct sk_buff *skb1; |
| 4474 | u32 seq, end_seq; |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4475 | bool fragstolen; |
Eric Dumazet | e86b2919 | 2012-03-18 11:06:44 +0000 | [diff] [blame] | 4476 | |
Yousuk Seung | f4c9f85 | 2018-06-04 15:29:51 -0700 | [diff] [blame] | 4477 | tcp_ecn_check_ce(sk, skb); |
Eric Dumazet | e86b2919 | 2012-03-18 11:06:44 +0000 | [diff] [blame] | 4478 | |
Mel Gorman | c76562b | 2012-07-31 16:44:41 -0700 | [diff] [blame] | 4479 | if (unlikely(tcp_try_rmem_schedule(sk, skb, skb->truesize))) { |
Eric Dumazet | c10d931 | 2016-04-29 14:16:47 -0700 | [diff] [blame] | 4480 | NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPOFODROP); |
Eric Dumazet | 532182c | 2016-04-01 08:52:19 -0700 | [diff] [blame] | 4481 | tcp_drop(sk, skb); |
Eric Dumazet | e86b2919 | 2012-03-18 11:06:44 +0000 | [diff] [blame] | 4482 | return; |
| 4483 | } |
| 4484 | |
Florian Westphal | 31770e3 | 2017-08-30 19:24:58 +0200 | [diff] [blame] | 4485 | /* Disable header prediction. */ |
| 4486 | tp->pred_flags = 0; |
Eric Dumazet | e86b2919 | 2012-03-18 11:06:44 +0000 | [diff] [blame] | 4487 | inet_csk_schedule_ack(sk); |
| 4488 | |
Eric Dumazet | c10d931 | 2016-04-29 14:16:47 -0700 | [diff] [blame] | 4489 | NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPOFOQUEUE); |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4490 | seq = TCP_SKB_CB(skb)->seq; |
| 4491 | end_seq = TCP_SKB_CB(skb)->end_seq; |
Eric Dumazet | e86b2919 | 2012-03-18 11:06:44 +0000 | [diff] [blame] | 4492 | |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4493 | p = &tp->out_of_order_queue.rb_node; |
| 4494 | if (RB_EMPTY_ROOT(&tp->out_of_order_queue)) { |
Eric Dumazet | e86b2919 | 2012-03-18 11:06:44 +0000 | [diff] [blame] | 4495 | /* Initial out of order segment, build 1 SACK. */ |
| 4496 | if (tcp_is_sack(tp)) { |
| 4497 | tp->rx_opt.num_sacks = 1; |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4498 | tp->selective_acks[0].start_seq = seq; |
| 4499 | tp->selective_acks[0].end_seq = end_seq; |
Eric Dumazet | e86b2919 | 2012-03-18 11:06:44 +0000 | [diff] [blame] | 4500 | } |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4501 | rb_link_node(&skb->rbnode, NULL, p); |
| 4502 | rb_insert_color(&skb->rbnode, &tp->out_of_order_queue); |
| 4503 | tp->ooo_last_skb = skb; |
Eric Dumazet | e86b2919 | 2012-03-18 11:06:44 +0000 | [diff] [blame] | 4504 | goto end; |
| 4505 | } |
| 4506 | |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4507 | /* In the typical case, we are adding an skb to the end of the list. |
| 4508 | * Use of ooo_last_skb avoids the O(Log(N)) rbtree lookup. |
| 4509 | */ |
Eric Dumazet | 58152ec | 2018-07-23 09:28:21 -0700 | [diff] [blame] | 4510 | if (tcp_ooo_try_coalesce(sk, tp->ooo_last_skb, |
| 4511 | skb, &fragstolen)) { |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4512 | coalesce_done: |
| 4513 | tcp_grow_window(sk, skb); |
| 4514 | kfree_skb_partial(skb, fragstolen); |
| 4515 | skb = NULL; |
| 4516 | goto add_sack; |
Eric Dumazet | e86b2919 | 2012-03-18 11:06:44 +0000 | [diff] [blame] | 4517 | } |
Eric Dumazet | 2594a2a | 2016-09-09 14:22:45 -0700 | [diff] [blame] | 4518 | /* Can avoid an rbtree lookup if we are adding skb after ooo_last_skb */ |
| 4519 | if (!before(seq, TCP_SKB_CB(tp->ooo_last_skb)->end_seq)) { |
| 4520 | parent = &tp->ooo_last_skb->rbnode; |
| 4521 | p = &parent->rb_right; |
| 4522 | goto insert; |
Eric Dumazet | e86b2919 | 2012-03-18 11:06:44 +0000 | [diff] [blame] | 4523 | } |
| 4524 | |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4525 | /* Find place to insert this segment. Handle overlaps on the way. */ |
| 4526 | parent = NULL; |
| 4527 | while (*p) { |
| 4528 | parent = *p; |
Eric Dumazet | 18a4c0e | 2017-10-05 22:21:21 -0700 | [diff] [blame] | 4529 | skb1 = rb_to_skb(parent); |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4530 | if (before(seq, TCP_SKB_CB(skb1)->seq)) { |
| 4531 | p = &parent->rb_left; |
| 4532 | continue; |
Eric Dumazet | e86b2919 | 2012-03-18 11:06:44 +0000 | [diff] [blame] | 4533 | } |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4534 | if (before(seq, TCP_SKB_CB(skb1)->end_seq)) { |
| 4535 | if (!after(end_seq, TCP_SKB_CB(skb1)->end_seq)) { |
| 4536 | /* All the bits are present. Drop. */ |
| 4537 | NET_INC_STATS(sock_net(sk), |
| 4538 | LINUX_MIB_TCPOFOMERGE); |
Eric Dumazet | 8541b21 | 2018-07-23 09:28:20 -0700 | [diff] [blame] | 4539 | tcp_drop(sk, skb); |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4540 | skb = NULL; |
| 4541 | tcp_dsack_set(sk, seq, end_seq); |
| 4542 | goto add_sack; |
| 4543 | } |
| 4544 | if (after(seq, TCP_SKB_CB(skb1)->seq)) { |
| 4545 | /* Partial overlap. */ |
| 4546 | tcp_dsack_set(sk, seq, TCP_SKB_CB(skb1)->end_seq); |
| 4547 | } else { |
| 4548 | /* skb's seq == skb1's seq and skb covers skb1. |
| 4549 | * Replace skb1 with skb. |
| 4550 | */ |
| 4551 | rb_replace_node(&skb1->rbnode, &skb->rbnode, |
| 4552 | &tp->out_of_order_queue); |
| 4553 | tcp_dsack_extend(sk, |
| 4554 | TCP_SKB_CB(skb1)->seq, |
| 4555 | TCP_SKB_CB(skb1)->end_seq); |
| 4556 | NET_INC_STATS(sock_net(sk), |
| 4557 | LINUX_MIB_TCPOFOMERGE); |
Eric Dumazet | 8541b21 | 2018-07-23 09:28:20 -0700 | [diff] [blame] | 4558 | tcp_drop(sk, skb1); |
Eric Dumazet | 76f0dcb | 2016-09-13 22:55:05 -0700 | [diff] [blame] | 4559 | goto merge_right; |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4560 | } |
Eric Dumazet | 58152ec | 2018-07-23 09:28:21 -0700 | [diff] [blame] | 4561 | } else if (tcp_ooo_try_coalesce(sk, skb1, |
| 4562 | skb, &fragstolen)) { |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4563 | goto coalesce_done; |
| 4564 | } |
| 4565 | p = &parent->rb_right; |
Eric Dumazet | e86b2919 | 2012-03-18 11:06:44 +0000 | [diff] [blame] | 4566 | } |
Eric Dumazet | 2594a2a | 2016-09-09 14:22:45 -0700 | [diff] [blame] | 4567 | insert: |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4568 | /* Insert segment into RB tree. */ |
| 4569 | rb_link_node(&skb->rbnode, parent, p); |
| 4570 | rb_insert_color(&skb->rbnode, &tp->out_of_order_queue); |
Eric Dumazet | e86b2919 | 2012-03-18 11:06:44 +0000 | [diff] [blame] | 4571 | |
Eric Dumazet | 76f0dcb | 2016-09-13 22:55:05 -0700 | [diff] [blame] | 4572 | merge_right: |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4573 | /* Remove other segments covered by skb. */ |
Eric Dumazet | 18a4c0e | 2017-10-05 22:21:21 -0700 | [diff] [blame] | 4574 | while ((skb1 = skb_rb_next(skb)) != NULL) { |
Eric Dumazet | e86b2919 | 2012-03-18 11:06:44 +0000 | [diff] [blame] | 4575 | if (!after(end_seq, TCP_SKB_CB(skb1)->seq)) |
| 4576 | break; |
| 4577 | if (before(end_seq, TCP_SKB_CB(skb1)->end_seq)) { |
| 4578 | tcp_dsack_extend(sk, TCP_SKB_CB(skb1)->seq, |
| 4579 | end_seq); |
| 4580 | break; |
| 4581 | } |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4582 | rb_erase(&skb1->rbnode, &tp->out_of_order_queue); |
Eric Dumazet | e86b2919 | 2012-03-18 11:06:44 +0000 | [diff] [blame] | 4583 | tcp_dsack_extend(sk, TCP_SKB_CB(skb1)->seq, |
| 4584 | TCP_SKB_CB(skb1)->end_seq); |
Eric Dumazet | c10d931 | 2016-04-29 14:16:47 -0700 | [diff] [blame] | 4585 | NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPOFOMERGE); |
Eric Dumazet | 532182c | 2016-04-01 08:52:19 -0700 | [diff] [blame] | 4586 | tcp_drop(sk, skb1); |
Eric Dumazet | e86b2919 | 2012-03-18 11:06:44 +0000 | [diff] [blame] | 4587 | } |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4588 | /* If there is no skb after us, we are the last_skb ! */ |
Eric Dumazet | 18a4c0e | 2017-10-05 22:21:21 -0700 | [diff] [blame] | 4589 | if (!skb1) |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4590 | tp->ooo_last_skb = skb; |
Eric Dumazet | e86b2919 | 2012-03-18 11:06:44 +0000 | [diff] [blame] | 4591 | |
| 4592 | add_sack: |
| 4593 | if (tcp_is_sack(tp)) |
| 4594 | tcp_sack_new_ofo_skb(sk, seq, end_seq); |
| 4595 | end: |
Eric Dumazet | 4e4f1fc | 2013-09-06 10:35:58 -0700 | [diff] [blame] | 4596 | if (skb) { |
| 4597 | tcp_grow_window(sk, skb); |
Eric Dumazet | 60b1af3 | 2017-01-24 14:57:36 -0800 | [diff] [blame] | 4598 | skb_condense(skb); |
Eric Dumazet | e86b2919 | 2012-03-18 11:06:44 +0000 | [diff] [blame] | 4599 | skb_set_owner_r(skb, sk); |
Eric Dumazet | 4e4f1fc | 2013-09-06 10:35:58 -0700 | [diff] [blame] | 4600 | } |
Eric Dumazet | e86b2919 | 2012-03-18 11:06:44 +0000 | [diff] [blame] | 4601 | } |
| 4602 | |
Eric Dumazet | e7395f1f | 2018-11-26 14:49:12 -0800 | [diff] [blame] | 4603 | static int __must_check tcp_queue_rcv(struct sock *sk, struct sk_buff *skb, |
| 4604 | bool *fragstolen) |
Eric Dumazet | b081f85 | 2012-05-02 09:58:29 +0000 | [diff] [blame] | 4605 | { |
| 4606 | int eaten; |
| 4607 | struct sk_buff *tail = skb_peek_tail(&sk->sk_receive_queue); |
| 4608 | |
Eric Dumazet | b081f85 | 2012-05-02 09:58:29 +0000 | [diff] [blame] | 4609 | eaten = (tail && |
Eric Dumazet | bffa72c | 2017-09-19 05:14:24 -0700 | [diff] [blame] | 4610 | tcp_try_coalesce(sk, tail, |
Mike Maloney | 98aaa91 | 2017-08-22 17:08:48 -0400 | [diff] [blame] | 4611 | skb, fragstolen)) ? 1 : 0; |
Eric Dumazet | bdd1f9e | 2015-04-28 15:28:18 -0700 | [diff] [blame] | 4612 | tcp_rcv_nxt_update(tcp_sk(sk), TCP_SKB_CB(skb)->end_seq); |
Eric Dumazet | b081f85 | 2012-05-02 09:58:29 +0000 | [diff] [blame] | 4613 | if (!eaten) { |
| 4614 | __skb_queue_tail(&sk->sk_receive_queue, skb); |
| 4615 | skb_set_owner_r(skb, sk); |
| 4616 | } |
| 4617 | return eaten; |
| 4618 | } |
Eric Dumazet | e86b2919 | 2012-03-18 11:06:44 +0000 | [diff] [blame] | 4619 | |
Pavel Emelyanov | 292e8d8 | 2012-05-10 01:49:41 +0000 | [diff] [blame] | 4620 | int tcp_send_rcvq(struct sock *sk, struct msghdr *msg, size_t size) |
| 4621 | { |
Eric Dumazet | cb93471 | 2014-09-17 03:14:42 -0700 | [diff] [blame] | 4622 | struct sk_buff *skb; |
Eric Dumazet | 5d4c9bf | 2015-11-18 21:03:33 -0800 | [diff] [blame] | 4623 | int err = -ENOMEM; |
| 4624 | int data_len = 0; |
Pavel Emelyanov | 292e8d8 | 2012-05-10 01:49:41 +0000 | [diff] [blame] | 4625 | bool fragstolen; |
| 4626 | |
Pavel Emelyanov | c454e61 | 2012-10-29 05:05:33 +0000 | [diff] [blame] | 4627 | if (size == 0) |
| 4628 | return 0; |
| 4629 | |
Eric Dumazet | 5d4c9bf | 2015-11-18 21:03:33 -0800 | [diff] [blame] | 4630 | if (size > PAGE_SIZE) { |
| 4631 | int npages = min_t(size_t, size >> PAGE_SHIFT, MAX_SKB_FRAGS); |
| 4632 | |
| 4633 | data_len = npages << PAGE_SHIFT; |
| 4634 | size = data_len + (size & ~PAGE_MASK); |
| 4635 | } |
| 4636 | skb = alloc_skb_with_frags(size - data_len, data_len, |
| 4637 | PAGE_ALLOC_COSTLY_ORDER, |
| 4638 | &err, sk->sk_allocation); |
Pavel Emelyanov | 292e8d8 | 2012-05-10 01:49:41 +0000 | [diff] [blame] | 4639 | if (!skb) |
| 4640 | goto err; |
| 4641 | |
Eric Dumazet | 5d4c9bf | 2015-11-18 21:03:33 -0800 | [diff] [blame] | 4642 | skb_put(skb, size - data_len); |
| 4643 | skb->data_len = data_len; |
| 4644 | skb->len = size; |
| 4645 | |
Yafang Shao | ea5d0c3 | 2018-06-28 00:22:56 -0400 | [diff] [blame] | 4646 | if (tcp_try_rmem_schedule(sk, skb, skb->truesize)) { |
| 4647 | NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPRCVQDROP); |
Mel Gorman | c76562b | 2012-07-31 16:44:41 -0700 | [diff] [blame] | 4648 | goto err_free; |
Yafang Shao | ea5d0c3 | 2018-06-28 00:22:56 -0400 | [diff] [blame] | 4649 | } |
Mel Gorman | c76562b | 2012-07-31 16:44:41 -0700 | [diff] [blame] | 4650 | |
Eric Dumazet | 5d4c9bf | 2015-11-18 21:03:33 -0800 | [diff] [blame] | 4651 | err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, size); |
| 4652 | if (err) |
Pavel Emelyanov | 292e8d8 | 2012-05-10 01:49:41 +0000 | [diff] [blame] | 4653 | goto err_free; |
| 4654 | |
| 4655 | TCP_SKB_CB(skb)->seq = tcp_sk(sk)->rcv_nxt; |
| 4656 | TCP_SKB_CB(skb)->end_seq = TCP_SKB_CB(skb)->seq + size; |
| 4657 | TCP_SKB_CB(skb)->ack_seq = tcp_sk(sk)->snd_una - 1; |
| 4658 | |
Eric Dumazet | e7395f1f | 2018-11-26 14:49:12 -0800 | [diff] [blame] | 4659 | if (tcp_queue_rcv(sk, skb, &fragstolen)) { |
Pavel Emelyanov | 292e8d8 | 2012-05-10 01:49:41 +0000 | [diff] [blame] | 4660 | WARN_ON_ONCE(fragstolen); /* should not happen */ |
| 4661 | __kfree_skb(skb); |
| 4662 | } |
| 4663 | return size; |
| 4664 | |
| 4665 | err_free: |
| 4666 | kfree_skb(skb); |
| 4667 | err: |
Eric Dumazet | 5d4c9bf | 2015-11-18 21:03:33 -0800 | [diff] [blame] | 4668 | return err; |
| 4669 | |
Pavel Emelyanov | 292e8d8 | 2012-05-10 01:49:41 +0000 | [diff] [blame] | 4670 | } |
| 4671 | |
Eric Dumazet | 03f45c8 | 2018-04-16 10:33:37 -0700 | [diff] [blame] | 4672 | void tcp_data_ready(struct sock *sk) |
| 4673 | { |
| 4674 | const struct tcp_sock *tp = tcp_sk(sk); |
| 4675 | int avail = tp->rcv_nxt - tp->copied_seq; |
| 4676 | |
| 4677 | if (avail < sk->sk_rcvlowat && !sock_flag(sk, SOCK_DONE)) |
| 4678 | return; |
| 4679 | |
| 4680 | sk->sk_data_ready(sk); |
| 4681 | } |
| 4682 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4683 | static void tcp_data_queue(struct sock *sk, struct sk_buff *skb) |
| 4684 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4685 | struct tcp_sock *tp = tcp_sk(sk); |
Eric Dumazet | 5357f0b | 2017-08-01 07:02:44 -0700 | [diff] [blame] | 4686 | bool fragstolen; |
| 4687 | int eaten; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4688 | |
Eric Dumazet | 532182c | 2016-04-01 08:52:19 -0700 | [diff] [blame] | 4689 | if (TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq) { |
| 4690 | __kfree_skb(skb); |
| 4691 | return; |
| 4692 | } |
Eric Dumazet | f84af32 | 2010-04-28 15:31:51 -0700 | [diff] [blame] | 4693 | skb_dst_drop(skb); |
Peter Pan(潘卫平) | 155c6e1 | 2014-09-24 22:17:02 +0800 | [diff] [blame] | 4694 | __skb_pull(skb, tcp_hdr(skb)->doff * 4); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4695 | |
Yuchung Cheng | fd2123a | 2018-08-09 09:38:12 -0700 | [diff] [blame] | 4696 | tcp_ecn_accept_cwr(sk, skb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4697 | |
Ilpo Järvinen | 5861f8e | 2009-03-14 14:23:01 +0000 | [diff] [blame] | 4698 | tp->rx_opt.dsack = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4699 | |
| 4700 | /* Queue data for delivery to the user. |
| 4701 | * Packets in sequence go to the receive queue. |
| 4702 | * Out of sequence packets to the out_of_order_queue. |
| 4703 | */ |
| 4704 | if (TCP_SKB_CB(skb)->seq == tp->rcv_nxt) { |
Yafang Shao | fb22350 | 2018-06-24 10:02:54 -0400 | [diff] [blame] | 4705 | if (tcp_receive_window(tp) == 0) { |
| 4706 | NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPZEROWINDOWDROP); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4707 | goto out_of_window; |
Yafang Shao | fb22350 | 2018-06-24 10:02:54 -0400 | [diff] [blame] | 4708 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4709 | |
| 4710 | /* Ok. In sequence. In window. */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4711 | queue_and_out: |
Eric Dumazet | 5357f0b | 2017-08-01 07:02:44 -0700 | [diff] [blame] | 4712 | if (skb_queue_len(&sk->sk_receive_queue) == 0) |
| 4713 | sk_forced_mem_schedule(sk, skb->truesize); |
Yafang Shao | ea5d0c3 | 2018-06-28 00:22:56 -0400 | [diff] [blame] | 4714 | else if (tcp_try_rmem_schedule(sk, skb, skb->truesize)) { |
| 4715 | NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPRCVQDROP); |
Eric Dumazet | 5357f0b | 2017-08-01 07:02:44 -0700 | [diff] [blame] | 4716 | goto drop; |
Yafang Shao | ea5d0c3 | 2018-06-28 00:22:56 -0400 | [diff] [blame] | 4717 | } |
Eric Dumazet | 5357f0b | 2017-08-01 07:02:44 -0700 | [diff] [blame] | 4718 | |
Eric Dumazet | e7395f1f | 2018-11-26 14:49:12 -0800 | [diff] [blame] | 4719 | eaten = tcp_queue_rcv(sk, skb, &fragstolen); |
Stephen Hemminger | 2de979b | 2007-03-08 20:45:19 -0800 | [diff] [blame] | 4720 | if (skb->len) |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 4721 | tcp_event_data_recv(sk, skb); |
Peter Pan(潘卫平) | 155c6e1 | 2014-09-24 22:17:02 +0800 | [diff] [blame] | 4722 | if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) |
Eric Dumazet | 20c4cb7 | 2011-10-20 17:44:03 -0400 | [diff] [blame] | 4723 | tcp_fin(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4724 | |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4725 | if (!RB_EMPTY_ROOT(&tp->out_of_order_queue)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4726 | tcp_ofo_queue(sk); |
| 4727 | |
Yuchung Cheng | 15bdd56 | 2018-08-09 09:38:11 -0700 | [diff] [blame] | 4728 | /* RFC5681. 4.2. SHOULD send immediate ACK, when |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4729 | * gap in queue is filled. |
| 4730 | */ |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4731 | if (RB_EMPTY_ROOT(&tp->out_of_order_queue)) |
Yuchung Cheng | 15bdd56 | 2018-08-09 09:38:11 -0700 | [diff] [blame] | 4732 | inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_NOW; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4733 | } |
| 4734 | |
| 4735 | if (tp->rx_opt.num_sacks) |
| 4736 | tcp_sack_remove(tp); |
| 4737 | |
Florian Westphal | 31770e3 | 2017-08-30 19:24:58 +0200 | [diff] [blame] | 4738 | tcp_fast_path_check(sk); |
| 4739 | |
Eric Dumazet | 923dd34 | 2012-05-02 07:55:58 +0000 | [diff] [blame] | 4740 | if (eaten > 0) |
| 4741 | kfree_skb_partial(skb, fragstolen); |
Eric Dumazet | 1d57f19 | 2012-09-17 12:51:39 +0000 | [diff] [blame] | 4742 | if (!sock_flag(sk, SOCK_DEAD)) |
Eric Dumazet | 03f45c8 | 2018-04-16 10:33:37 -0700 | [diff] [blame] | 4743 | tcp_data_ready(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4744 | return; |
| 4745 | } |
| 4746 | |
| 4747 | if (!after(TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt)) { |
Yuchung Cheng | 7788174 | 2018-08-29 14:53:56 -0700 | [diff] [blame] | 4748 | tcp_rcv_spurious_retrans(sk, skb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4749 | /* A retransmit, 2nd most common case. Force an immediate ack. */ |
Eric Dumazet | c10d931 | 2016-04-29 14:16:47 -0700 | [diff] [blame] | 4750 | NET_INC_STATS(sock_net(sk), LINUX_MIB_DELAYEDACKLOST); |
Pavel Emelyanov | 1ed8346 | 2008-07-16 20:29:51 -0700 | [diff] [blame] | 4751 | tcp_dsack_set(sk, TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4752 | |
| 4753 | out_of_window: |
Eric Dumazet | 9a9c9b5 | 2018-05-21 15:08:56 -0700 | [diff] [blame] | 4754 | tcp_enter_quickack_mode(sk, TCP_MAX_QUICKACKS); |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 4755 | inet_csk_schedule_ack(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4756 | drop: |
Eric Dumazet | 532182c | 2016-04-01 08:52:19 -0700 | [diff] [blame] | 4757 | tcp_drop(sk, skb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4758 | return; |
| 4759 | } |
| 4760 | |
| 4761 | /* Out of window. F.e. zero window probe. */ |
| 4762 | if (!before(TCP_SKB_CB(skb)->seq, tp->rcv_nxt + tcp_receive_window(tp))) |
| 4763 | goto out_of_window; |
| 4764 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4765 | if (before(TCP_SKB_CB(skb)->seq, tp->rcv_nxt)) { |
| 4766 | /* Partial packet, seq < rcv_next < end_seq */ |
Pavel Emelyanov | 1ed8346 | 2008-07-16 20:29:51 -0700 | [diff] [blame] | 4767 | tcp_dsack_set(sk, TCP_SKB_CB(skb)->seq, tp->rcv_nxt); |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 4768 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4769 | /* If window is closed, drop tail of packet. But after |
| 4770 | * remembering D-SACK for its head made in previous line. |
| 4771 | */ |
Yafang Shao | fb22350 | 2018-06-24 10:02:54 -0400 | [diff] [blame] | 4772 | if (!tcp_receive_window(tp)) { |
| 4773 | NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPZEROWINDOWDROP); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4774 | goto out_of_window; |
Yafang Shao | fb22350 | 2018-06-24 10:02:54 -0400 | [diff] [blame] | 4775 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4776 | goto queue_and_out; |
| 4777 | } |
| 4778 | |
Eric Dumazet | e86b2919 | 2012-03-18 11:06:44 +0000 | [diff] [blame] | 4779 | tcp_data_queue_ofo(sk, skb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4780 | } |
| 4781 | |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4782 | static struct sk_buff *tcp_skb_next(struct sk_buff *skb, struct sk_buff_head *list) |
Ilpo Järvinen | 2cf4663 | 2008-08-23 05:11:41 -0700 | [diff] [blame] | 4783 | { |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4784 | if (list) |
| 4785 | return !skb_queue_is_last(list, skb) ? skb->next : NULL; |
David S. Miller | 9152194 | 2009-05-28 21:35:47 -0700 | [diff] [blame] | 4786 | |
Eric Dumazet | 18a4c0e | 2017-10-05 22:21:21 -0700 | [diff] [blame] | 4787 | return skb_rb_next(skb); |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4788 | } |
Ilpo Järvinen | 2cf4663 | 2008-08-23 05:11:41 -0700 | [diff] [blame] | 4789 | |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4790 | static struct sk_buff *tcp_collapse_one(struct sock *sk, struct sk_buff *skb, |
| 4791 | struct sk_buff_head *list, |
| 4792 | struct rb_root *root) |
| 4793 | { |
| 4794 | struct sk_buff *next = tcp_skb_next(skb, list); |
| 4795 | |
| 4796 | if (list) |
| 4797 | __skb_unlink(skb, list); |
| 4798 | else |
| 4799 | rb_erase(&skb->rbnode, root); |
| 4800 | |
Ilpo Järvinen | 2cf4663 | 2008-08-23 05:11:41 -0700 | [diff] [blame] | 4801 | __kfree_skb(skb); |
Eric Dumazet | c10d931 | 2016-04-29 14:16:47 -0700 | [diff] [blame] | 4802 | NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPRCVCOLLAPSED); |
Ilpo Järvinen | 2cf4663 | 2008-08-23 05:11:41 -0700 | [diff] [blame] | 4803 | |
| 4804 | return next; |
| 4805 | } |
| 4806 | |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4807 | /* Insert skb into rb tree, ordered by TCP_SKB_CB(skb)->seq */ |
Eric Dumazet | 75c119a | 2017-10-05 22:21:27 -0700 | [diff] [blame] | 4808 | void tcp_rbtree_insert(struct rb_root *root, struct sk_buff *skb) |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4809 | { |
| 4810 | struct rb_node **p = &root->rb_node; |
| 4811 | struct rb_node *parent = NULL; |
| 4812 | struct sk_buff *skb1; |
| 4813 | |
| 4814 | while (*p) { |
| 4815 | parent = *p; |
Eric Dumazet | 18a4c0e | 2017-10-05 22:21:21 -0700 | [diff] [blame] | 4816 | skb1 = rb_to_skb(parent); |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4817 | if (before(TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb1)->seq)) |
| 4818 | p = &parent->rb_left; |
| 4819 | else |
| 4820 | p = &parent->rb_right; |
| 4821 | } |
| 4822 | rb_link_node(&skb->rbnode, parent, p); |
| 4823 | rb_insert_color(&skb->rbnode, root); |
| 4824 | } |
| 4825 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4826 | /* Collapse contiguous sequence of skbs head..tail with |
| 4827 | * sequence numbers start..end. |
David S. Miller | 9152194 | 2009-05-28 21:35:47 -0700 | [diff] [blame] | 4828 | * |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4829 | * If tail is NULL, this means until the end of the queue. |
David S. Miller | 9152194 | 2009-05-28 21:35:47 -0700 | [diff] [blame] | 4830 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4831 | * Segments with FIN/SYN are not collapsed (only because this |
| 4832 | * simplifies code) |
| 4833 | */ |
| 4834 | static void |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4835 | tcp_collapse(struct sock *sk, struct sk_buff_head *list, struct rb_root *root, |
| 4836 | struct sk_buff *head, struct sk_buff *tail, u32 start, u32 end) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4837 | { |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4838 | struct sk_buff *skb = head, *n; |
| 4839 | struct sk_buff_head tmp; |
David S. Miller | 9152194 | 2009-05-28 21:35:47 -0700 | [diff] [blame] | 4840 | bool end_of_skbs; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4841 | |
Stephen Hemminger | caa20d9a | 2005-11-10 17:13:47 -0800 | [diff] [blame] | 4842 | /* First, check that queue is collapsible and find |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4843 | * the point where collapsing can be useful. |
| 4844 | */ |
David S. Miller | 9152194 | 2009-05-28 21:35:47 -0700 | [diff] [blame] | 4845 | restart: |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4846 | for (end_of_skbs = true; skb != NULL && skb != tail; skb = n) { |
| 4847 | n = tcp_skb_next(skb, list); |
| 4848 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4849 | /* No new bits? It is possible on ofo queue. */ |
| 4850 | if (!before(start, TCP_SKB_CB(skb)->end_seq)) { |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4851 | skb = tcp_collapse_one(sk, skb, list, root); |
David S. Miller | 9152194 | 2009-05-28 21:35:47 -0700 | [diff] [blame] | 4852 | if (!skb) |
| 4853 | break; |
| 4854 | goto restart; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4855 | } |
| 4856 | |
| 4857 | /* The first skb to collapse is: |
| 4858 | * - not SYN/FIN and |
| 4859 | * - bloated or contains data before "start" or |
| 4860 | * overlaps to the next one. |
| 4861 | */ |
Eric Dumazet | e11ecdd | 2014-09-15 04:19:51 -0700 | [diff] [blame] | 4862 | if (!(TCP_SKB_CB(skb)->tcp_flags & (TCPHDR_SYN | TCPHDR_FIN)) && |
Eric Dumazet | 94f0893 | 2017-10-26 21:55:09 -0700 | [diff] [blame] | 4863 | (tcp_win_from_space(sk, skb->truesize) > skb->len || |
David S. Miller | 9152194 | 2009-05-28 21:35:47 -0700 | [diff] [blame] | 4864 | before(TCP_SKB_CB(skb)->seq, start))) { |
| 4865 | end_of_skbs = false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4866 | break; |
David S. Miller | 9152194 | 2009-05-28 21:35:47 -0700 | [diff] [blame] | 4867 | } |
| 4868 | |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4869 | if (n && n != tail && |
| 4870 | TCP_SKB_CB(skb)->end_seq != TCP_SKB_CB(n)->seq) { |
| 4871 | end_of_skbs = false; |
| 4872 | break; |
David S. Miller | 9152194 | 2009-05-28 21:35:47 -0700 | [diff] [blame] | 4873 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4874 | |
| 4875 | /* Decided to skip this, advance start seq. */ |
| 4876 | start = TCP_SKB_CB(skb)->end_seq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4877 | } |
Eric Dumazet | e11ecdd | 2014-09-15 04:19:51 -0700 | [diff] [blame] | 4878 | if (end_of_skbs || |
| 4879 | (TCP_SKB_CB(skb)->tcp_flags & (TCPHDR_SYN | TCPHDR_FIN))) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4880 | return; |
| 4881 | |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4882 | __skb_queue_head_init(&tmp); |
| 4883 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4884 | while (before(start, end)) { |
Eric Dumazet | b3d6cb9 | 2014-09-15 04:19:53 -0700 | [diff] [blame] | 4885 | int copy = min_t(int, SKB_MAX_ORDER(0, 0), end - start); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4886 | struct sk_buff *nskb; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4887 | |
Eric Dumazet | b3d6cb9 | 2014-09-15 04:19:53 -0700 | [diff] [blame] | 4888 | nskb = alloc_skb(copy, GFP_ATOMIC); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4889 | if (!nskb) |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4890 | break; |
Arnaldo Carvalho de Melo | c51957d | 2007-03-10 12:47:22 -0300 | [diff] [blame] | 4891 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4892 | memcpy(nskb->cb, skb->cb, sizeof(skb->cb)); |
Boris Pismenny | 41ed9c0 | 2018-07-13 14:33:38 +0300 | [diff] [blame] | 4893 | #ifdef CONFIG_TLS_DEVICE |
| 4894 | nskb->decrypted = skb->decrypted; |
| 4895 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4896 | TCP_SKB_CB(nskb)->seq = TCP_SKB_CB(nskb)->end_seq = start; |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4897 | if (list) |
| 4898 | __skb_queue_before(list, skb, nskb); |
| 4899 | else |
| 4900 | __skb_queue_tail(&tmp, nskb); /* defer rbtree insertion */ |
Hideo Aoki | 3ab224b | 2007-12-31 00:11:19 -0800 | [diff] [blame] | 4901 | skb_set_owner_r(nskb, sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4902 | |
| 4903 | /* Copy data, releasing collapsed skbs. */ |
| 4904 | while (copy > 0) { |
| 4905 | int offset = start - TCP_SKB_CB(skb)->seq; |
| 4906 | int size = TCP_SKB_CB(skb)->end_seq - start; |
| 4907 | |
Kris Katterjohn | 09a6266 | 2006-01-08 22:24:28 -0800 | [diff] [blame] | 4908 | BUG_ON(offset < 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4909 | if (size > 0) { |
| 4910 | size = min(copy, size); |
| 4911 | if (skb_copy_bits(skb, offset, skb_put(nskb, size), size)) |
| 4912 | BUG(); |
| 4913 | TCP_SKB_CB(nskb)->end_seq += size; |
| 4914 | copy -= size; |
| 4915 | start += size; |
| 4916 | } |
| 4917 | if (!before(start, TCP_SKB_CB(skb)->end_seq)) { |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4918 | skb = tcp_collapse_one(sk, skb, list, root); |
David S. Miller | 9152194 | 2009-05-28 21:35:47 -0700 | [diff] [blame] | 4919 | if (!skb || |
| 4920 | skb == tail || |
Eric Dumazet | e11ecdd | 2014-09-15 04:19:51 -0700 | [diff] [blame] | 4921 | (TCP_SKB_CB(skb)->tcp_flags & (TCPHDR_SYN | TCPHDR_FIN))) |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4922 | goto end; |
Boris Pismenny | 41ed9c0 | 2018-07-13 14:33:38 +0300 | [diff] [blame] | 4923 | #ifdef CONFIG_TLS_DEVICE |
| 4924 | if (skb->decrypted != nskb->decrypted) |
| 4925 | goto end; |
| 4926 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4927 | } |
| 4928 | } |
| 4929 | } |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4930 | end: |
| 4931 | skb_queue_walk_safe(&tmp, skb, n) |
| 4932 | tcp_rbtree_insert(root, skb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4933 | } |
| 4934 | |
| 4935 | /* Collapse ofo queue. Algorithm: select contiguous sequence of skbs |
| 4936 | * and tcp_collapse() them until all the queue is collapsed. |
| 4937 | */ |
| 4938 | static void tcp_collapse_ofo_queue(struct sock *sk) |
| 4939 | { |
| 4940 | struct tcp_sock *tp = tcp_sk(sk); |
Eric Dumazet | 3d4bf93 | 2018-07-23 09:28:19 -0700 | [diff] [blame] | 4941 | u32 range_truesize, sum_tiny = 0; |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4942 | struct sk_buff *skb, *head; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4943 | u32 start, end; |
| 4944 | |
Eric Dumazet | 18a4c0e | 2017-10-05 22:21:21 -0700 | [diff] [blame] | 4945 | skb = skb_rb_first(&tp->out_of_order_queue); |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4946 | new_range: |
| 4947 | if (!skb) { |
Eric Dumazet | 18a4c0e | 2017-10-05 22:21:21 -0700 | [diff] [blame] | 4948 | tp->ooo_last_skb = skb_rb_last(&tp->out_of_order_queue); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4949 | return; |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4950 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4951 | start = TCP_SKB_CB(skb)->seq; |
| 4952 | end = TCP_SKB_CB(skb)->end_seq; |
Eric Dumazet | 3d4bf93 | 2018-07-23 09:28:19 -0700 | [diff] [blame] | 4953 | range_truesize = skb->truesize; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4954 | |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4955 | for (head = skb;;) { |
Eric Dumazet | 18a4c0e | 2017-10-05 22:21:21 -0700 | [diff] [blame] | 4956 | skb = skb_rb_next(skb); |
David S. Miller | 9152194 | 2009-05-28 21:35:47 -0700 | [diff] [blame] | 4957 | |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4958 | /* Range is terminated when we see a gap or when |
| 4959 | * we are at the queue end. |
| 4960 | */ |
David S. Miller | 9152194 | 2009-05-28 21:35:47 -0700 | [diff] [blame] | 4961 | if (!skb || |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4962 | after(TCP_SKB_CB(skb)->seq, end) || |
| 4963 | before(TCP_SKB_CB(skb)->end_seq, start)) { |
Eric Dumazet | 3d4bf93 | 2018-07-23 09:28:19 -0700 | [diff] [blame] | 4964 | /* Do not attempt collapsing tiny skbs */ |
| 4965 | if (range_truesize != head->truesize || |
| 4966 | end - start >= SKB_WITH_OVERHEAD(SK_MEM_QUANTUM)) { |
| 4967 | tcp_collapse(sk, NULL, &tp->out_of_order_queue, |
| 4968 | head, skb, start, end); |
| 4969 | } else { |
| 4970 | sum_tiny += range_truesize; |
| 4971 | if (sum_tiny > sk->sk_rcvbuf >> 3) |
| 4972 | return; |
| 4973 | } |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4974 | goto new_range; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4975 | } |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4976 | |
Eric Dumazet | 3d4bf93 | 2018-07-23 09:28:19 -0700 | [diff] [blame] | 4977 | range_truesize += skb->truesize; |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4978 | if (unlikely(before(TCP_SKB_CB(skb)->seq, start))) |
| 4979 | start = TCP_SKB_CB(skb)->seq; |
| 4980 | if (after(TCP_SKB_CB(skb)->end_seq, end)) |
| 4981 | end = TCP_SKB_CB(skb)->end_seq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4982 | } |
| 4983 | } |
| 4984 | |
Vitaliy Gusev | b000cd3 | 2008-04-15 00:33:38 -0700 | [diff] [blame] | 4985 | /* |
Eric Dumazet | 36a6503 | 2016-08-17 14:17:09 -0700 | [diff] [blame] | 4986 | * Clean the out-of-order queue to make room. |
| 4987 | * We drop high sequences packets to : |
| 4988 | * 1) Let a chance for holes to be filled. |
| 4989 | * 2) not add too big latencies if thousands of packets sit there. |
| 4990 | * (But if application shrinks SO_RCVBUF, we could still end up |
| 4991 | * freeing whole queue here) |
Eric Dumazet | 72cd43b | 2018-07-23 09:28:17 -0700 | [diff] [blame] | 4992 | * 3) Drop at least 12.5 % of sk_rcvbuf to avoid malicious attacks. |
Eric Dumazet | 36a6503 | 2016-08-17 14:17:09 -0700 | [diff] [blame] | 4993 | * |
| 4994 | * Return true if queue has shrunk. |
Vitaliy Gusev | b000cd3 | 2008-04-15 00:33:38 -0700 | [diff] [blame] | 4995 | */ |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 4996 | static bool tcp_prune_ofo_queue(struct sock *sk) |
Vitaliy Gusev | b000cd3 | 2008-04-15 00:33:38 -0700 | [diff] [blame] | 4997 | { |
| 4998 | struct tcp_sock *tp = tcp_sk(sk); |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 4999 | struct rb_node *node, *prev; |
Eric Dumazet | 72cd43b | 2018-07-23 09:28:17 -0700 | [diff] [blame] | 5000 | int goal; |
Vitaliy Gusev | b000cd3 | 2008-04-15 00:33:38 -0700 | [diff] [blame] | 5001 | |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 5002 | if (RB_EMPTY_ROOT(&tp->out_of_order_queue)) |
Eric Dumazet | 36a6503 | 2016-08-17 14:17:09 -0700 | [diff] [blame] | 5003 | return false; |
Vitaliy Gusev | b000cd3 | 2008-04-15 00:33:38 -0700 | [diff] [blame] | 5004 | |
Eric Dumazet | 36a6503 | 2016-08-17 14:17:09 -0700 | [diff] [blame] | 5005 | NET_INC_STATS(sock_net(sk), LINUX_MIB_OFOPRUNED); |
Eric Dumazet | 72cd43b | 2018-07-23 09:28:17 -0700 | [diff] [blame] | 5006 | goal = sk->sk_rcvbuf >> 3; |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 5007 | node = &tp->ooo_last_skb->rbnode; |
| 5008 | do { |
| 5009 | prev = rb_prev(node); |
| 5010 | rb_erase(node, &tp->out_of_order_queue); |
Eric Dumazet | 72cd43b | 2018-07-23 09:28:17 -0700 | [diff] [blame] | 5011 | goal -= rb_to_skb(node)->truesize; |
Eric Dumazet | 18a4c0e | 2017-10-05 22:21:21 -0700 | [diff] [blame] | 5012 | tcp_drop(sk, rb_to_skb(node)); |
Eric Dumazet | 72cd43b | 2018-07-23 09:28:17 -0700 | [diff] [blame] | 5013 | if (!prev || goal <= 0) { |
| 5014 | sk_mem_reclaim(sk); |
| 5015 | if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf && |
| 5016 | !tcp_under_memory_pressure(sk)) |
| 5017 | break; |
| 5018 | goal = sk->sk_rcvbuf >> 3; |
| 5019 | } |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 5020 | node = prev; |
| 5021 | } while (node); |
Eric Dumazet | 18a4c0e | 2017-10-05 22:21:21 -0700 | [diff] [blame] | 5022 | tp->ooo_last_skb = rb_to_skb(prev); |
Eric Dumazet | 36a6503 | 2016-08-17 14:17:09 -0700 | [diff] [blame] | 5023 | |
| 5024 | /* Reset SACK state. A conforming SACK implementation will |
| 5025 | * do the same at a timeout based retransmit. When a connection |
| 5026 | * is in a sad state like this, we care only about integrity |
| 5027 | * of the connection not performance. |
| 5028 | */ |
| 5029 | if (tp->rx_opt.sack_ok) |
| 5030 | tcp_sack_reset(&tp->rx_opt); |
| 5031 | return true; |
Vitaliy Gusev | b000cd3 | 2008-04-15 00:33:38 -0700 | [diff] [blame] | 5032 | } |
| 5033 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5034 | /* Reduce allocated memory if we can, trying to get |
| 5035 | * the socket within its memory limits again. |
| 5036 | * |
| 5037 | * Return less than zero if we should start dropping frames |
| 5038 | * until the socket owning process reads some of the data |
| 5039 | * to stabilize the situation. |
| 5040 | */ |
| 5041 | static int tcp_prune_queue(struct sock *sk) |
| 5042 | { |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 5043 | struct tcp_sock *tp = tcp_sk(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5044 | |
Eric Dumazet | c10d931 | 2016-04-29 14:16:47 -0700 | [diff] [blame] | 5045 | NET_INC_STATS(sock_net(sk), LINUX_MIB_PRUNECALLED); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5046 | |
| 5047 | if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf) |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 5048 | tcp_clamp_window(sk); |
Eric Dumazet | b8da51e | 2015-05-15 12:39:27 -0700 | [diff] [blame] | 5049 | else if (tcp_under_memory_pressure(sk)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5050 | tp->rcv_ssthresh = min(tp->rcv_ssthresh, 4U * tp->advmss); |
| 5051 | |
Eric Dumazet | f4a3313 | 2018-07-23 09:28:18 -0700 | [diff] [blame] | 5052 | if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf) |
| 5053 | return 0; |
| 5054 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5055 | tcp_collapse_ofo_queue(sk); |
David S. Miller | 9152194 | 2009-05-28 21:35:47 -0700 | [diff] [blame] | 5056 | if (!skb_queue_empty(&sk->sk_receive_queue)) |
Yaogong Wang | 9f5afea | 2016-09-07 14:49:28 -0700 | [diff] [blame] | 5057 | tcp_collapse(sk, &sk->sk_receive_queue, NULL, |
David S. Miller | 9152194 | 2009-05-28 21:35:47 -0700 | [diff] [blame] | 5058 | skb_peek(&sk->sk_receive_queue), |
| 5059 | NULL, |
| 5060 | tp->copied_seq, tp->rcv_nxt); |
Hideo Aoki | 3ab224b | 2007-12-31 00:11:19 -0800 | [diff] [blame] | 5061 | sk_mem_reclaim(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5062 | |
| 5063 | if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf) |
| 5064 | return 0; |
| 5065 | |
| 5066 | /* Collapsing did not help, destructive actions follow. |
| 5067 | * This must not ever occur. */ |
| 5068 | |
Vitaliy Gusev | b000cd3 | 2008-04-15 00:33:38 -0700 | [diff] [blame] | 5069 | tcp_prune_ofo_queue(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5070 | |
| 5071 | if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf) |
| 5072 | return 0; |
| 5073 | |
| 5074 | /* If we are really being abused, tell the caller to silently |
| 5075 | * drop receive data on the floor. It will get retransmitted |
| 5076 | * and hopefully then we'll have sufficient space. |
| 5077 | */ |
Eric Dumazet | c10d931 | 2016-04-29 14:16:47 -0700 | [diff] [blame] | 5078 | NET_INC_STATS(sock_net(sk), LINUX_MIB_RCVPRUNED); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5079 | |
| 5080 | /* Massive buffer overcommit. */ |
Florian Westphal | 31770e3 | 2017-08-30 19:24:58 +0200 | [diff] [blame] | 5081 | tp->pred_flags = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5082 | return -1; |
| 5083 | } |
| 5084 | |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 5085 | static bool tcp_should_expand_sndbuf(const struct sock *sk) |
David S. Miller | 0d9901d | 2005-07-05 15:21:10 -0700 | [diff] [blame] | 5086 | { |
Eric Dumazet | cf533ea | 2011-10-21 05:22:42 -0400 | [diff] [blame] | 5087 | const struct tcp_sock *tp = tcp_sk(sk); |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 5088 | |
David S. Miller | 0d9901d | 2005-07-05 15:21:10 -0700 | [diff] [blame] | 5089 | /* If the user specified a specific send buffer setting, do |
| 5090 | * not modify it. |
| 5091 | */ |
| 5092 | if (sk->sk_userlocks & SOCK_SNDBUF_LOCK) |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 5093 | return false; |
David S. Miller | 0d9901d | 2005-07-05 15:21:10 -0700 | [diff] [blame] | 5094 | |
| 5095 | /* If we are under global TCP memory pressure, do not expand. */ |
Eric Dumazet | b8da51e | 2015-05-15 12:39:27 -0700 | [diff] [blame] | 5096 | if (tcp_under_memory_pressure(sk)) |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 5097 | return false; |
David S. Miller | 0d9901d | 2005-07-05 15:21:10 -0700 | [diff] [blame] | 5098 | |
| 5099 | /* If we are under soft global TCP memory pressure, do not expand. */ |
Glauber Costa | 180d8cd | 2011-12-11 21:47:02 +0000 | [diff] [blame] | 5100 | if (sk_memory_allocated(sk) >= sk_prot_mem_limits(sk, 0)) |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 5101 | return false; |
David S. Miller | 0d9901d | 2005-07-05 15:21:10 -0700 | [diff] [blame] | 5102 | |
| 5103 | /* If we filled the congestion window, do not expand. */ |
Neal Cardwell | 6514890 | 2015-02-20 13:33:16 -0500 | [diff] [blame] | 5104 | if (tcp_packets_in_flight(tp) >= tp->snd_cwnd) |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 5105 | return false; |
David S. Miller | 0d9901d | 2005-07-05 15:21:10 -0700 | [diff] [blame] | 5106 | |
Eric Dumazet | a2a385d | 2012-05-16 23:15:34 +0000 | [diff] [blame] | 5107 | return true; |
David S. Miller | 0d9901d | 2005-07-05 15:21:10 -0700 | [diff] [blame] | 5108 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5109 | |
| 5110 | /* When incoming ACK allowed to free some skb from write_queue, |
| 5111 | * we remember this event in flag SOCK_QUEUE_SHRUNK and wake up socket |
| 5112 | * on the exit from tcp input handler. |
| 5113 | * |
| 5114 | * PROBLEM: sndbuf expansion does not work well with largesend. |
| 5115 | */ |
| 5116 | static void tcp_new_space(struct sock *sk) |
| 5117 | { |
| 5118 | struct tcp_sock *tp = tcp_sk(sk); |
| 5119 | |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 5120 | if (tcp_should_expand_sndbuf(sk)) { |
Eric Dumazet | 6ae7053 | 2013-10-01 10:23:44 -0700 | [diff] [blame] | 5121 | tcp_sndbuf_expand(sk); |
Eric Dumazet | c2203cf | 2017-05-16 14:00:04 -0700 | [diff] [blame] | 5122 | tp->snd_cwnd_stamp = tcp_jiffies32; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5123 | } |
| 5124 | |
| 5125 | sk->sk_write_space(sk); |
| 5126 | } |
| 5127 | |
Stephen Hemminger | 40efc6f | 2006-01-03 16:03:49 -0800 | [diff] [blame] | 5128 | static void tcp_check_space(struct sock *sk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5129 | { |
| 5130 | if (sock_flag(sk, SOCK_QUEUE_SHRUNK)) { |
| 5131 | sock_reset_flag(sk, SOCK_QUEUE_SHRUNK); |
jbaron@akamai.com | 3c71512 | 2015-04-20 20:05:07 +0000 | [diff] [blame] | 5132 | /* pairs with tcp_poll() */ |
Jason Baron | 56d8062 | 2017-01-24 21:49:41 -0500 | [diff] [blame] | 5133 | smp_mb(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5134 | if (sk->sk_socket && |
Francis Yan | b0f71bd | 2016-11-27 23:07:16 -0800 | [diff] [blame] | 5135 | test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5136 | tcp_new_space(sk); |
Francis Yan | b0f71bd | 2016-11-27 23:07:16 -0800 | [diff] [blame] | 5137 | if (!test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) |
| 5138 | tcp_chrono_stop(sk, TCP_CHRONO_SNDBUF_LIMITED); |
| 5139 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5140 | } |
| 5141 | } |
| 5142 | |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 5143 | static inline void tcp_data_snd_check(struct sock *sk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5144 | { |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 5145 | tcp_push_pending_frames(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5146 | tcp_check_space(sk); |
| 5147 | } |
| 5148 | |
| 5149 | /* |
| 5150 | * Check if sending an ack is needed. |
| 5151 | */ |
| 5152 | static void __tcp_ack_snd_check(struct sock *sk, int ofo_possible) |
| 5153 | { |
| 5154 | struct tcp_sock *tp = tcp_sk(sk); |
Eric Dumazet | 5d9f426 | 2018-05-17 14:47:26 -0700 | [diff] [blame] | 5155 | unsigned long rtt, delay; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5156 | |
| 5157 | /* More than one full frame received... */ |
Joe Perches | 9d4fb27 | 2009-11-23 10:41:23 -0800 | [diff] [blame] | 5158 | if (((tp->rcv_nxt - tp->rcv_wup) > inet_csk(sk)->icsk_ack.rcv_mss && |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5159 | /* ... and right edge of window advances far enough. |
Eric Dumazet | 796f82e | 2018-04-16 10:33:36 -0700 | [diff] [blame] | 5160 | * (tcp_recvmsg() will send ACK otherwise). |
| 5161 | * If application uses SO_RCVLOWAT, we want send ack now if |
| 5162 | * we have not received enough bytes to satisfy the condition. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5163 | */ |
Eric Dumazet | 796f82e | 2018-04-16 10:33:36 -0700 | [diff] [blame] | 5164 | (tp->rcv_nxt - tp->copied_seq < sk->sk_rcvlowat || |
| 5165 | __tcp_select_window(sk) >= tp->rcv_wnd)) || |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5166 | /* We ACK each frame or... */ |
Yuchung Cheng | 466466d | 2018-08-09 09:38:09 -0700 | [diff] [blame] | 5167 | tcp_in_quickack_mode(sk) || |
| 5168 | /* Protocol state mandates a one-time immediate ACK */ |
| 5169 | inet_csk(sk)->icsk_ack.pending & ICSK_ACK_NOW) { |
Eric Dumazet | 5d9f426 | 2018-05-17 14:47:26 -0700 | [diff] [blame] | 5170 | send_now: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5171 | tcp_send_ack(sk); |
Eric Dumazet | 5d9f426 | 2018-05-17 14:47:26 -0700 | [diff] [blame] | 5172 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5173 | } |
Eric Dumazet | 5d9f426 | 2018-05-17 14:47:26 -0700 | [diff] [blame] | 5174 | |
| 5175 | if (!ofo_possible || RB_EMPTY_ROOT(&tp->out_of_order_queue)) { |
| 5176 | tcp_send_delayed_ack(sk); |
| 5177 | return; |
| 5178 | } |
| 5179 | |
Eric Dumazet | 9c21d2f | 2018-05-17 14:47:29 -0700 | [diff] [blame] | 5180 | if (!tcp_is_sack(tp) || |
| 5181 | tp->compressed_ack >= sock_net(sk)->ipv4.sysctl_tcp_comp_sack_nr) |
Eric Dumazet | 5d9f426 | 2018-05-17 14:47:26 -0700 | [diff] [blame] | 5182 | goto send_now; |
Eric Dumazet | 86de592 | 2018-11-20 05:53:59 -0800 | [diff] [blame] | 5183 | |
| 5184 | if (tp->compressed_ack_rcv_nxt != tp->rcv_nxt) { |
| 5185 | tp->compressed_ack_rcv_nxt = tp->rcv_nxt; |
| 5186 | if (tp->compressed_ack > TCP_FASTRETRANS_THRESH) |
| 5187 | NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPACKCOMPRESSED, |
| 5188 | tp->compressed_ack - TCP_FASTRETRANS_THRESH); |
| 5189 | tp->compressed_ack = 0; |
| 5190 | } |
| 5191 | |
| 5192 | if (++tp->compressed_ack <= TCP_FASTRETRANS_THRESH) |
| 5193 | goto send_now; |
Eric Dumazet | 5d9f426 | 2018-05-17 14:47:26 -0700 | [diff] [blame] | 5194 | |
| 5195 | if (hrtimer_is_queued(&tp->compressed_ack_timer)) |
| 5196 | return; |
| 5197 | |
Eric Dumazet | 6d82aa2 | 2018-05-17 14:47:28 -0700 | [diff] [blame] | 5198 | /* compress ack timer : 5 % of rtt, but no more than tcp_comp_sack_delay_ns */ |
Eric Dumazet | 5d9f426 | 2018-05-17 14:47:26 -0700 | [diff] [blame] | 5199 | |
| 5200 | rtt = tp->rcv_rtt_est.rtt_us; |
| 5201 | if (tp->srtt_us && tp->srtt_us < rtt) |
| 5202 | rtt = tp->srtt_us; |
| 5203 | |
Eric Dumazet | 6d82aa2 | 2018-05-17 14:47:28 -0700 | [diff] [blame] | 5204 | delay = min_t(unsigned long, sock_net(sk)->ipv4.sysctl_tcp_comp_sack_delay_ns, |
Eric Dumazet | 5d9f426 | 2018-05-17 14:47:26 -0700 | [diff] [blame] | 5205 | rtt * (NSEC_PER_USEC >> 3)/20); |
| 5206 | sock_hold(sk); |
| 5207 | hrtimer_start(&tp->compressed_ack_timer, ns_to_ktime(delay), |
| 5208 | HRTIMER_MODE_REL_PINNED_SOFT); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5209 | } |
| 5210 | |
Stephen Hemminger | 40efc6f | 2006-01-03 16:03:49 -0800 | [diff] [blame] | 5211 | static inline void tcp_ack_snd_check(struct sock *sk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5212 | { |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 5213 | if (!inet_csk_ack_scheduled(sk)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5214 | /* We sent a data segment already. */ |
| 5215 | return; |
| 5216 | } |
| 5217 | __tcp_ack_snd_check(sk, 1); |
| 5218 | } |
| 5219 | |
| 5220 | /* |
| 5221 | * This routine is only called when we have urgent data |
Stephen Hemminger | caa20d9a | 2005-11-10 17:13:47 -0800 | [diff] [blame] | 5222 | * signaled. Its the 'slow' part of tcp_urg. It could be |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5223 | * moved inline now as tcp_urg is only called from one |
| 5224 | * place. We handle URGent data wrong. We have to - as |
| 5225 | * BSD still doesn't use the correction from RFC961. |
| 5226 | * For 1003.1g we should support a new option TCP_STDURG to permit |
| 5227 | * either form (or just set the sysctl tcp_stdurg). |
| 5228 | */ |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 5229 | |
Eric Dumazet | cf533ea | 2011-10-21 05:22:42 -0400 | [diff] [blame] | 5230 | static void tcp_check_urg(struct sock *sk, const struct tcphdr *th) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5231 | { |
| 5232 | struct tcp_sock *tp = tcp_sk(sk); |
| 5233 | u32 ptr = ntohs(th->urg_ptr); |
| 5234 | |
Eric Dumazet | 3f4c7c6 | 2017-10-26 21:55:01 -0700 | [diff] [blame] | 5235 | if (ptr && !sock_net(sk)->ipv4.sysctl_tcp_stdurg) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5236 | ptr--; |
| 5237 | ptr += ntohl(th->seq); |
| 5238 | |
| 5239 | /* Ignore urgent data that we've already seen and read. */ |
| 5240 | if (after(tp->copied_seq, ptr)) |
| 5241 | return; |
| 5242 | |
| 5243 | /* Do not replay urg ptr. |
| 5244 | * |
| 5245 | * NOTE: interesting situation not covered by specs. |
| 5246 | * Misbehaving sender may send urg ptr, pointing to segment, |
| 5247 | * which we already have in ofo queue. We are not able to fetch |
| 5248 | * such data and will stay in TCP_URG_NOTYET until will be eaten |
| 5249 | * by recvmsg(). Seems, we are not obliged to handle such wicked |
| 5250 | * situations. But it is worth to think about possibility of some |
| 5251 | * DoSes using some hypothetical application level deadlock. |
| 5252 | */ |
| 5253 | if (before(ptr, tp->rcv_nxt)) |
| 5254 | return; |
| 5255 | |
| 5256 | /* Do we already have a newer (or duplicate) urgent pointer? */ |
| 5257 | if (tp->urg_data && !after(ptr, tp->urg_seq)) |
| 5258 | return; |
| 5259 | |
| 5260 | /* Tell the world about our new urgent pointer. */ |
| 5261 | sk_send_sigurg(sk); |
| 5262 | |
| 5263 | /* We may be adding urgent data when the last byte read was |
| 5264 | * urgent. To do this requires some care. We cannot just ignore |
| 5265 | * tp->copied_seq since we would read the last urgent byte again |
| 5266 | * as data, nor can we alter copied_seq until this data arrives |
Stephen Hemminger | caa20d9a | 2005-11-10 17:13:47 -0800 | [diff] [blame] | 5267 | * or we break the semantics of SIOCATMARK (and thus sockatmark()) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5268 | * |
| 5269 | * NOTE. Double Dutch. Rendering to plain English: author of comment |
| 5270 | * above did something sort of send("A", MSG_OOB); send("B", MSG_OOB); |
| 5271 | * and expect that both A and B disappear from stream. This is _wrong_. |
| 5272 | * Though this happens in BSD with high probability, this is occasional. |
| 5273 | * Any application relying on this is buggy. Note also, that fix "works" |
| 5274 | * only in this artificial test. Insert some normal data between A and B and we will |
| 5275 | * decline of BSD again. Verdict: it is better to remove to trap |
| 5276 | * buggy users. |
| 5277 | */ |
| 5278 | if (tp->urg_seq == tp->copied_seq && tp->urg_data && |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 5279 | !sock_flag(sk, SOCK_URGINLINE) && tp->copied_seq != tp->rcv_nxt) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5280 | struct sk_buff *skb = skb_peek(&sk->sk_receive_queue); |
| 5281 | tp->copied_seq++; |
| 5282 | if (skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq)) { |
David S. Miller | 8728b83 | 2005-08-09 19:25:21 -0700 | [diff] [blame] | 5283 | __skb_unlink(skb, &sk->sk_receive_queue); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5284 | __kfree_skb(skb); |
| 5285 | } |
| 5286 | } |
| 5287 | |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 5288 | tp->urg_data = TCP_URG_NOTYET; |
| 5289 | tp->urg_seq = ptr; |
Florian Westphal | 31770e3 | 2017-08-30 19:24:58 +0200 | [diff] [blame] | 5290 | |
| 5291 | /* Disable header prediction. */ |
| 5292 | tp->pred_flags = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5293 | } |
| 5294 | |
| 5295 | /* This is the 'fast' part of urgent handling. */ |
Eric Dumazet | cf533ea | 2011-10-21 05:22:42 -0400 | [diff] [blame] | 5296 | static void tcp_urg(struct sock *sk, struct sk_buff *skb, const struct tcphdr *th) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5297 | { |
| 5298 | struct tcp_sock *tp = tcp_sk(sk); |
| 5299 | |
| 5300 | /* Check if we get a new urgent pointer - normally not. */ |
| 5301 | if (th->urg) |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 5302 | tcp_check_urg(sk, th); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5303 | |
| 5304 | /* Do we wait for any urgent data? - normally not... */ |
| 5305 | if (tp->urg_data == TCP_URG_NOTYET) { |
| 5306 | u32 ptr = tp->urg_seq - ntohl(th->seq) + (th->doff * 4) - |
| 5307 | th->syn; |
| 5308 | |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 5309 | /* Is the urgent pointer pointing into this packet? */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5310 | if (ptr < skb->len) { |
| 5311 | u8 tmp; |
| 5312 | if (skb_copy_bits(skb, ptr, &tmp, 1)) |
| 5313 | BUG(); |
| 5314 | tp->urg_data = TCP_URG_VALID | tmp; |
| 5315 | if (!sock_flag(sk, SOCK_DEAD)) |
David S. Miller | 676d236 | 2014-04-11 16:15:36 -0400 | [diff] [blame] | 5316 | sk->sk_data_ready(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5317 | } |
| 5318 | } |
| 5319 | } |
| 5320 | |
Jason Baron | 0e40f4c | 2017-01-17 13:37:19 -0500 | [diff] [blame] | 5321 | /* Accept RST for rcv_nxt - 1 after a FIN. |
| 5322 | * When tcp connections are abruptly terminated from Mac OSX (via ^C), a |
| 5323 | * FIN is sent followed by a RST packet. The RST is sent with the same |
| 5324 | * sequence number as the FIN, and thus according to RFC 5961 a challenge |
| 5325 | * ACK should be sent. However, Mac OSX rate limits replies to challenge |
| 5326 | * ACKs on the closed socket. In addition middleboxes can drop either the |
| 5327 | * challenge ACK or a subsequent RST. |
| 5328 | */ |
| 5329 | static bool tcp_reset_check(const struct sock *sk, const struct sk_buff *skb) |
| 5330 | { |
| 5331 | struct tcp_sock *tp = tcp_sk(sk); |
| 5332 | |
| 5333 | return unlikely(TCP_SKB_CB(skb)->seq == (tp->rcv_nxt - 1) && |
| 5334 | (1 << sk->sk_state) & (TCPF_CLOSE_WAIT | TCPF_LAST_ACK | |
| 5335 | TCPF_CLOSING)); |
| 5336 | } |
| 5337 | |
Ilpo Järvinen | cbe2d12 | 2008-08-23 05:10:12 -0700 | [diff] [blame] | 5338 | /* Does PAWS and seqno based validation of an incoming segment, flags will |
| 5339 | * play significant role here. |
| 5340 | */ |
Eric Dumazet | 0c24604 | 2012-07-17 01:41:30 +0000 | [diff] [blame] | 5341 | static bool tcp_validate_incoming(struct sock *sk, struct sk_buff *skb, |
| 5342 | const struct tcphdr *th, int syn_inerr) |
Ilpo Järvinen | cbe2d12 | 2008-08-23 05:10:12 -0700 | [diff] [blame] | 5343 | { |
| 5344 | struct tcp_sock *tp = tcp_sk(sk); |
Pau Espin Pedrol | e00431b | 2016-06-07 16:30:34 +0200 | [diff] [blame] | 5345 | bool rst_seq_match = false; |
Ilpo Järvinen | cbe2d12 | 2008-08-23 05:10:12 -0700 | [diff] [blame] | 5346 | |
| 5347 | /* RFC1323: H1. Apply PAWS check first. */ |
Eric Dumazet | eed29f1 | 2017-06-07 10:34:36 -0700 | [diff] [blame] | 5348 | if (tcp_fast_parse_options(sock_net(sk), skb, th, tp) && |
| 5349 | tp->rx_opt.saw_tstamp && |
Ilpo Järvinen | cbe2d12 | 2008-08-23 05:10:12 -0700 | [diff] [blame] | 5350 | tcp_paws_discard(sk, skb)) { |
| 5351 | if (!th->rst) { |
Eric Dumazet | c10d931 | 2016-04-29 14:16:47 -0700 | [diff] [blame] | 5352 | NET_INC_STATS(sock_net(sk), LINUX_MIB_PAWSESTABREJECTED); |
Neal Cardwell | f2b2c58 | 2015-02-06 16:04:40 -0500 | [diff] [blame] | 5353 | if (!tcp_oow_rate_limited(sock_net(sk), skb, |
| 5354 | LINUX_MIB_TCPACKSKIPPEDPAWS, |
| 5355 | &tp->last_oow_ack_time)) |
| 5356 | tcp_send_dupack(sk, skb); |
Ilpo Järvinen | cbe2d12 | 2008-08-23 05:10:12 -0700 | [diff] [blame] | 5357 | goto discard; |
| 5358 | } |
| 5359 | /* Reset is accepted even if it did not pass PAWS. */ |
| 5360 | } |
| 5361 | |
| 5362 | /* Step 1: check sequence number */ |
| 5363 | if (!tcp_sequence(tp, TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq)) { |
| 5364 | /* RFC793, page 37: "In all states except SYN-SENT, all reset |
| 5365 | * (RST) segments are validated by checking their SEQ-fields." |
| 5366 | * And page 69: "If an incoming segment is not acceptable, |
| 5367 | * an acknowledgment should be sent in reply (unless the RST |
| 5368 | * bit is set, if so drop the segment and return)". |
| 5369 | */ |
Eric Dumazet | e371589 | 2012-07-17 12:29:30 +0000 | [diff] [blame] | 5370 | if (!th->rst) { |
| 5371 | if (th->syn) |
| 5372 | goto syn_challenge; |
Neal Cardwell | f2b2c58 | 2015-02-06 16:04:40 -0500 | [diff] [blame] | 5373 | if (!tcp_oow_rate_limited(sock_net(sk), skb, |
| 5374 | LINUX_MIB_TCPACKSKIPPEDSEQ, |
| 5375 | &tp->last_oow_ack_time)) |
| 5376 | tcp_send_dupack(sk, skb); |
Jason Baron | 0e40f4c | 2017-01-17 13:37:19 -0500 | [diff] [blame] | 5377 | } else if (tcp_reset_check(sk, skb)) { |
| 5378 | tcp_reset(sk); |
Eric Dumazet | e371589 | 2012-07-17 12:29:30 +0000 | [diff] [blame] | 5379 | } |
Ilpo Järvinen | cbe2d12 | 2008-08-23 05:10:12 -0700 | [diff] [blame] | 5380 | goto discard; |
| 5381 | } |
| 5382 | |
| 5383 | /* Step 2: check RST bit */ |
| 5384 | if (th->rst) { |
Jason Baron | 0e40f4c | 2017-01-17 13:37:19 -0500 | [diff] [blame] | 5385 | /* RFC 5961 3.2 (extend to match against (RCV.NXT - 1) after a |
| 5386 | * FIN and SACK too if available): |
| 5387 | * If seq num matches RCV.NXT or (RCV.NXT - 1) after a FIN, or |
| 5388 | * the right-most SACK block, |
Pau Espin Pedrol | e00431b | 2016-06-07 16:30:34 +0200 | [diff] [blame] | 5389 | * then |
Eric Dumazet | 282f23c | 2012-07-17 10:13:05 +0200 | [diff] [blame] | 5390 | * RESET the connection |
| 5391 | * else |
| 5392 | * Send a challenge ACK |
| 5393 | */ |
Jason Baron | 0e40f4c | 2017-01-17 13:37:19 -0500 | [diff] [blame] | 5394 | if (TCP_SKB_CB(skb)->seq == tp->rcv_nxt || |
| 5395 | tcp_reset_check(sk, skb)) { |
Pau Espin Pedrol | e00431b | 2016-06-07 16:30:34 +0200 | [diff] [blame] | 5396 | rst_seq_match = true; |
| 5397 | } else if (tcp_is_sack(tp) && tp->rx_opt.num_sacks > 0) { |
| 5398 | struct tcp_sack_block *sp = &tp->selective_acks[0]; |
| 5399 | int max_sack = sp[0].end_seq; |
| 5400 | int this_sack; |
| 5401 | |
| 5402 | for (this_sack = 1; this_sack < tp->rx_opt.num_sacks; |
| 5403 | ++this_sack) { |
| 5404 | max_sack = after(sp[this_sack].end_seq, |
| 5405 | max_sack) ? |
| 5406 | sp[this_sack].end_seq : max_sack; |
| 5407 | } |
| 5408 | |
| 5409 | if (TCP_SKB_CB(skb)->seq == max_sack) |
| 5410 | rst_seq_match = true; |
| 5411 | } |
| 5412 | |
| 5413 | if (rst_seq_match) |
Eric Dumazet | 282f23c | 2012-07-17 10:13:05 +0200 | [diff] [blame] | 5414 | tcp_reset(sk); |
Wei Wang | cf1ef3f | 2017-04-20 14:45:46 -0700 | [diff] [blame] | 5415 | else { |
| 5416 | /* Disable TFO if RST is out-of-order |
| 5417 | * and no data has been received |
| 5418 | * for current active TFO socket |
| 5419 | */ |
| 5420 | if (tp->syn_fastopen && !tp->data_segs_in && |
| 5421 | sk->sk_state == TCP_ESTABLISHED) |
Wei Wang | 46c2fa3 | 2017-04-20 14:45:47 -0700 | [diff] [blame] | 5422 | tcp_fastopen_active_disable(sk); |
Neal Cardwell | f2b2c58 | 2015-02-06 16:04:40 -0500 | [diff] [blame] | 5423 | tcp_send_challenge_ack(sk, skb); |
Wei Wang | cf1ef3f | 2017-04-20 14:45:46 -0700 | [diff] [blame] | 5424 | } |
Ilpo Järvinen | cbe2d12 | 2008-08-23 05:10:12 -0700 | [diff] [blame] | 5425 | goto discard; |
| 5426 | } |
| 5427 | |
Ilpo Järvinen | cbe2d12 | 2008-08-23 05:10:12 -0700 | [diff] [blame] | 5428 | /* step 3: check security and precedence [ignored] */ |
| 5429 | |
Eric Dumazet | 0c24604 | 2012-07-17 01:41:30 +0000 | [diff] [blame] | 5430 | /* step 4: Check for a SYN |
Sowmini Varadhan | cd21453 | 2014-10-30 12:48:08 -0400 | [diff] [blame] | 5431 | * RFC 5961 4.2 : Send a challenge ack |
Eric Dumazet | 0c24604 | 2012-07-17 01:41:30 +0000 | [diff] [blame] | 5432 | */ |
| 5433 | if (th->syn) { |
Eric Dumazet | e371589 | 2012-07-17 12:29:30 +0000 | [diff] [blame] | 5434 | syn_challenge: |
Ilpo Järvinen | cbe2d12 | 2008-08-23 05:10:12 -0700 | [diff] [blame] | 5435 | if (syn_inerr) |
Eric Dumazet | c10d931 | 2016-04-29 14:16:47 -0700 | [diff] [blame] | 5436 | TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS); |
| 5437 | NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPSYNCHALLENGE); |
Neal Cardwell | f2b2c58 | 2015-02-06 16:04:40 -0500 | [diff] [blame] | 5438 | tcp_send_challenge_ack(sk, skb); |
Eric Dumazet | 0c24604 | 2012-07-17 01:41:30 +0000 | [diff] [blame] | 5439 | goto discard; |
Ilpo Järvinen | cbe2d12 | 2008-08-23 05:10:12 -0700 | [diff] [blame] | 5440 | } |
| 5441 | |
Eric Dumazet | 0c24604 | 2012-07-17 01:41:30 +0000 | [diff] [blame] | 5442 | return true; |
Ilpo Järvinen | cbe2d12 | 2008-08-23 05:10:12 -0700 | [diff] [blame] | 5443 | |
| 5444 | discard: |
Eric Dumazet | 532182c | 2016-04-01 08:52:19 -0700 | [diff] [blame] | 5445 | tcp_drop(sk, skb); |
Eric Dumazet | 0c24604 | 2012-07-17 01:41:30 +0000 | [diff] [blame] | 5446 | return false; |
Ilpo Järvinen | cbe2d12 | 2008-08-23 05:10:12 -0700 | [diff] [blame] | 5447 | } |
| 5448 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5449 | /* |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 5450 | * TCP receive function for the ESTABLISHED state. |
Florian Westphal | 31770e3 | 2017-08-30 19:24:58 +0200 | [diff] [blame] | 5451 | * |
| 5452 | * It is split into a fast path and a slow path. The fast path is |
| 5453 | * disabled when: |
| 5454 | * - A zero window was announced from us - zero window probing |
| 5455 | * is only handled properly in the slow path. |
| 5456 | * - Out of order segments arrived. |
| 5457 | * - Urgent data is expected. |
| 5458 | * - There is no buffer space left |
| 5459 | * - Unexpected TCP flags/window values/header lengths are received |
| 5460 | * (detected by checking the TCP header against pred_flags) |
| 5461 | * - Data is sent in both directions. Fast path only supports pure senders |
| 5462 | * or pure receivers (this means either the sequence number or the ack |
| 5463 | * value must stay constant) |
| 5464 | * - Unexpected TCP option. |
| 5465 | * |
| 5466 | * When these conditions are not satisfied it drops into a standard |
| 5467 | * receive procedure patterned after RFC793 to handle all cases. |
| 5468 | * The first three cases are guaranteed by proper pred_flags setting, |
| 5469 | * the rest is checked inline. Fast processing is turned on in |
| 5470 | * tcp_data_queue when everything is OK. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5471 | */ |
Yafang Shao | 3d97d88 | 2018-05-29 23:27:31 +0800 | [diff] [blame] | 5472 | void tcp_rcv_established(struct sock *sk, struct sk_buff *skb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5473 | { |
Yafang Shao | 3d97d88 | 2018-05-29 23:27:31 +0800 | [diff] [blame] | 5474 | const struct tcphdr *th = (const struct tcphdr *)skb->data; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5475 | struct tcp_sock *tp = tcp_sk(sk); |
Yafang Shao | 3d97d88 | 2018-05-29 23:27:31 +0800 | [diff] [blame] | 5476 | unsigned int len = skb->len; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5477 | |
Masami Hiramatsu | c3fde1b | 2017-12-29 11:45:51 +0900 | [diff] [blame] | 5478 | /* TCP congestion window tracking */ |
| 5479 | trace_tcp_probe(sk, skb); |
| 5480 | |
Eric Dumazet | 9a568de | 2017-05-16 14:00:14 -0700 | [diff] [blame] | 5481 | tcp_mstamp_refresh(tp); |
Ian Morris | 51456b2 | 2015-04-03 09:17:26 +0100 | [diff] [blame] | 5482 | if (unlikely(!sk->sk_rx_dst)) |
Eric Dumazet | 5d299f3 | 2012-08-06 05:09:33 +0000 | [diff] [blame] | 5483 | inet_csk(sk)->icsk_af_ops->sk_rx_dst_set(sk, skb); |
Florian Westphal | 31770e3 | 2017-08-30 19:24:58 +0200 | [diff] [blame] | 5484 | /* |
| 5485 | * Header prediction. |
| 5486 | * The code loosely follows the one in the famous |
| 5487 | * "30 instruction TCP receive" Van Jacobson mail. |
| 5488 | * |
| 5489 | * Van's trick is to deposit buffers into socket queue |
| 5490 | * on a device interrupt, to call tcp_recv function |
| 5491 | * on the receive process context and checksum and copy |
| 5492 | * the buffer to user space. smart... |
| 5493 | * |
| 5494 | * Our current scheme is not silly either but we take the |
| 5495 | * extra cost of the net_bh soft interrupt processing... |
| 5496 | * We do checksum and copy also but from device to kernel. |
| 5497 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5498 | |
| 5499 | tp->rx_opt.saw_tstamp = 0; |
| 5500 | |
Florian Westphal | 31770e3 | 2017-08-30 19:24:58 +0200 | [diff] [blame] | 5501 | /* pred_flags is 0xS?10 << 16 + snd_wnd |
| 5502 | * if header_prediction is to be made |
| 5503 | * 'S' will always be tp->tcp_header_len >> 2 |
| 5504 | * '?' will be 0 for the fast path, otherwise pred_flags is 0 to |
| 5505 | * turn it off (when there are holes in the receive |
| 5506 | * space for instance) |
| 5507 | * PSH flag is ignored. |
| 5508 | */ |
| 5509 | |
| 5510 | if ((tcp_flag_word(th) & TCP_HP_BITS) == tp->pred_flags && |
| 5511 | TCP_SKB_CB(skb)->seq == tp->rcv_nxt && |
| 5512 | !after(TCP_SKB_CB(skb)->ack_seq, tp->snd_nxt)) { |
| 5513 | int tcp_header_len = tp->tcp_header_len; |
| 5514 | |
| 5515 | /* Timestamp header prediction: tcp_header_len |
| 5516 | * is automatically equal to th->doff*4 due to pred_flags |
| 5517 | * match. |
| 5518 | */ |
| 5519 | |
| 5520 | /* Check timestamp */ |
| 5521 | if (tcp_header_len == sizeof(struct tcphdr) + TCPOLEN_TSTAMP_ALIGNED) { |
| 5522 | /* No? Slow path! */ |
| 5523 | if (!tcp_parse_aligned_timestamp(tp, th)) |
| 5524 | goto slow_path; |
| 5525 | |
| 5526 | /* If PAWS failed, check it more carefully in slow path */ |
| 5527 | if ((s32)(tp->rx_opt.rcv_tsval - tp->rx_opt.ts_recent) < 0) |
| 5528 | goto slow_path; |
| 5529 | |
| 5530 | /* DO NOT update ts_recent here, if checksum fails |
| 5531 | * and timestamp was corrupted part, it will result |
| 5532 | * in a hung connection since we will drop all |
| 5533 | * future packets due to the PAWS test. |
| 5534 | */ |
| 5535 | } |
| 5536 | |
| 5537 | if (len <= tcp_header_len) { |
| 5538 | /* Bulk data transfer: sender */ |
| 5539 | if (len == tcp_header_len) { |
| 5540 | /* Predicted packet is in window by definition. |
| 5541 | * seq == rcv_nxt and rcv_wup <= rcv_nxt. |
| 5542 | * Hence, check seq<=rcv_wup reduces to: |
| 5543 | */ |
| 5544 | if (tcp_header_len == |
| 5545 | (sizeof(struct tcphdr) + TCPOLEN_TSTAMP_ALIGNED) && |
| 5546 | tp->rcv_nxt == tp->rcv_wup) |
| 5547 | tcp_store_ts_recent(tp); |
| 5548 | |
| 5549 | /* We know that such packets are checksummed |
| 5550 | * on entry. |
| 5551 | */ |
| 5552 | tcp_ack(sk, skb, 0); |
| 5553 | __kfree_skb(skb); |
| 5554 | tcp_data_snd_check(sk); |
Wei Wang | 3f6c65d | 2018-06-19 21:42:50 -0700 | [diff] [blame] | 5555 | /* When receiving pure ack in fast path, update |
| 5556 | * last ts ecr directly instead of calling |
| 5557 | * tcp_rcv_rtt_measure_ts() |
| 5558 | */ |
| 5559 | tp->rcv_rtt_last_tsecr = tp->rx_opt.rcv_tsecr; |
Florian Westphal | 31770e3 | 2017-08-30 19:24:58 +0200 | [diff] [blame] | 5560 | return; |
| 5561 | } else { /* Header too small */ |
| 5562 | TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS); |
| 5563 | goto discard; |
| 5564 | } |
| 5565 | } else { |
| 5566 | int eaten = 0; |
| 5567 | bool fragstolen = false; |
| 5568 | |
| 5569 | if (tcp_checksum_complete(skb)) |
| 5570 | goto csum_error; |
| 5571 | |
| 5572 | if ((int)skb->truesize > sk->sk_forward_alloc) |
| 5573 | goto step5; |
| 5574 | |
| 5575 | /* Predicted packet is in window by definition. |
| 5576 | * seq == rcv_nxt and rcv_wup <= rcv_nxt. |
| 5577 | * Hence, check seq<=rcv_wup reduces to: |
| 5578 | */ |
| 5579 | if (tcp_header_len == |
| 5580 | (sizeof(struct tcphdr) + TCPOLEN_TSTAMP_ALIGNED) && |
| 5581 | tp->rcv_nxt == tp->rcv_wup) |
| 5582 | tcp_store_ts_recent(tp); |
| 5583 | |
| 5584 | tcp_rcv_rtt_measure_ts(sk, skb); |
| 5585 | |
| 5586 | NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPHPHITS); |
| 5587 | |
| 5588 | /* Bulk data transfer: receiver */ |
Eric Dumazet | e7395f1f | 2018-11-26 14:49:12 -0800 | [diff] [blame] | 5589 | __skb_pull(skb, tcp_header_len); |
| 5590 | eaten = tcp_queue_rcv(sk, skb, &fragstolen); |
Florian Westphal | 31770e3 | 2017-08-30 19:24:58 +0200 | [diff] [blame] | 5591 | |
| 5592 | tcp_event_data_recv(sk, skb); |
| 5593 | |
| 5594 | if (TCP_SKB_CB(skb)->ack_seq != tp->snd_una) { |
| 5595 | /* Well, only one small jumplet in fast path... */ |
| 5596 | tcp_ack(sk, skb, FLAG_DATA); |
| 5597 | tcp_data_snd_check(sk); |
| 5598 | if (!inet_csk_ack_scheduled(sk)) |
| 5599 | goto no_ack; |
| 5600 | } |
| 5601 | |
| 5602 | __tcp_ack_snd_check(sk, 0); |
| 5603 | no_ack: |
| 5604 | if (eaten) |
| 5605 | kfree_skb_partial(skb, fragstolen); |
Eric Dumazet | 03f45c8 | 2018-04-16 10:33:37 -0700 | [diff] [blame] | 5606 | tcp_data_ready(sk); |
Florian Westphal | 31770e3 | 2017-08-30 19:24:58 +0200 | [diff] [blame] | 5607 | return; |
| 5608 | } |
| 5609 | } |
| 5610 | |
| 5611 | slow_path: |
Eric Dumazet | fb3477c | 2016-04-29 14:16:48 -0700 | [diff] [blame] | 5612 | if (len < (th->doff << 2) || tcp_checksum_complete(skb)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5613 | goto csum_error; |
| 5614 | |
Calvin Owens | 0c228e8 | 2014-11-20 15:09:53 -0800 | [diff] [blame] | 5615 | if (!th->ack && !th->rst && !th->syn) |
Eric Dumazet | c3ae62af | 2012-12-26 12:44:34 +0000 | [diff] [blame] | 5616 | goto discard; |
| 5617 | |
Florian Westphal | 31770e3 | 2017-08-30 19:24:58 +0200 | [diff] [blame] | 5618 | /* |
| 5619 | * Standard slow path. |
| 5620 | */ |
| 5621 | |
Eric Dumazet | 0c24604 | 2012-07-17 01:41:30 +0000 | [diff] [blame] | 5622 | if (!tcp_validate_incoming(sk, skb, th, 1)) |
Vijay Subramanian | c995ae2 | 2013-09-03 12:23:22 -0700 | [diff] [blame] | 5623 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5624 | |
Florian Westphal | 31770e3 | 2017-08-30 19:24:58 +0200 | [diff] [blame] | 5625 | step5: |
| 5626 | if (tcp_ack(sk, skb, FLAG_SLOWPATH | FLAG_UPDATE_TS_RECENT) < 0) |
John Dykstra | 96e0bf4 | 2009-03-22 21:49:57 -0700 | [diff] [blame] | 5627 | goto discard; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5628 | |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 5629 | tcp_rcv_rtt_measure_ts(sk, skb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5630 | |
| 5631 | /* Process urgent data. */ |
| 5632 | tcp_urg(sk, skb, th); |
| 5633 | |
| 5634 | /* step 7: process the segment text */ |
| 5635 | tcp_data_queue(sk, skb); |
| 5636 | |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 5637 | tcp_data_snd_check(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5638 | tcp_ack_snd_check(sk); |
Vijay Subramanian | c995ae2 | 2013-09-03 12:23:22 -0700 | [diff] [blame] | 5639 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5640 | |
| 5641 | csum_error: |
Eric Dumazet | c10d931 | 2016-04-29 14:16:47 -0700 | [diff] [blame] | 5642 | TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS); |
| 5643 | TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5644 | |
| 5645 | discard: |
Eric Dumazet | 532182c | 2016-04-01 08:52:19 -0700 | [diff] [blame] | 5646 | tcp_drop(sk, skb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5647 | } |
Eric Dumazet | 4bc2f18 | 2010-07-09 21:22:10 +0000 | [diff] [blame] | 5648 | EXPORT_SYMBOL(tcp_rcv_established); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5649 | |
Pavel Emelyanov | 370816a | 2012-04-19 03:40:01 +0000 | [diff] [blame] | 5650 | void tcp_finish_connect(struct sock *sk, struct sk_buff *skb) |
| 5651 | { |
| 5652 | struct tcp_sock *tp = tcp_sk(sk); |
| 5653 | struct inet_connection_sock *icsk = inet_csk(sk); |
| 5654 | |
| 5655 | tcp_set_state(sk, TCP_ESTABLISHED); |
Eric Dumazet | 70eabf0 | 2017-05-16 14:00:07 -0700 | [diff] [blame] | 5656 | icsk->icsk_ack.lrcvtime = tcp_jiffies32; |
Pavel Emelyanov | 370816a | 2012-04-19 03:40:01 +0000 | [diff] [blame] | 5657 | |
Ian Morris | 00db412 | 2015-04-03 09:17:27 +0100 | [diff] [blame] | 5658 | if (skb) { |
Eric Dumazet | 5d299f3 | 2012-08-06 05:09:33 +0000 | [diff] [blame] | 5659 | icsk->icsk_af_ops->sk_rx_dst_set(sk, skb); |
Pavel Emelyanov | 370816a | 2012-04-19 03:40:01 +0000 | [diff] [blame] | 5660 | security_inet_conn_established(sk, skb); |
Amritha Nambiar | c6345ce | 2018-06-29 21:26:57 -0700 | [diff] [blame] | 5661 | sk_mark_napi_id(sk, skb); |
David S. Miller | 41063e9 | 2012-06-19 21:22:05 -0700 | [diff] [blame] | 5662 | } |
Pavel Emelyanov | 370816a | 2012-04-19 03:40:01 +0000 | [diff] [blame] | 5663 | |
Wei Wang | 27204aa | 2017-10-04 10:03:44 -0700 | [diff] [blame] | 5664 | tcp_init_transfer(sk, BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB); |
Pavel Emelyanov | 370816a | 2012-04-19 03:40:01 +0000 | [diff] [blame] | 5665 | |
| 5666 | /* Prevent spurious tcp_cwnd_restart() on first data |
| 5667 | * packet. |
| 5668 | */ |
Eric Dumazet | d635fbe | 2017-05-16 14:00:03 -0700 | [diff] [blame] | 5669 | tp->lsndtime = tcp_jiffies32; |
Pavel Emelyanov | 370816a | 2012-04-19 03:40:01 +0000 | [diff] [blame] | 5670 | |
Pavel Emelyanov | 370816a | 2012-04-19 03:40:01 +0000 | [diff] [blame] | 5671 | if (sock_flag(sk, SOCK_KEEPOPEN)) |
| 5672 | inet_csk_reset_keepalive_timer(sk, keepalive_time_when(tp)); |
Florian Westphal | 31770e3 | 2017-08-30 19:24:58 +0200 | [diff] [blame] | 5673 | |
| 5674 | if (!tp->rx_opt.snd_wscale) |
| 5675 | __tcp_fast_path_on(tp, tp->snd_wnd); |
| 5676 | else |
| 5677 | tp->pred_flags = 0; |
Pavel Emelyanov | 370816a | 2012-04-19 03:40:01 +0000 | [diff] [blame] | 5678 | } |
| 5679 | |
Yuchung Cheng | 8e4178c | 2012-07-19 06:43:08 +0000 | [diff] [blame] | 5680 | static bool tcp_rcv_fastopen_synack(struct sock *sk, struct sk_buff *synack, |
| 5681 | struct tcp_fastopen_cookie *cookie) |
| 5682 | { |
| 5683 | struct tcp_sock *tp = tcp_sk(sk); |
Eric Dumazet | 75c119a | 2017-10-05 22:21:27 -0700 | [diff] [blame] | 5684 | struct sk_buff *data = tp->syn_data ? tcp_rtx_queue_head(sk) : NULL; |
Daniel Lee | 2646c83 | 2015-04-06 14:37:27 -0700 | [diff] [blame] | 5685 | u16 mss = tp->rx_opt.mss_clamp, try_exp = 0; |
| 5686 | bool syn_drop = false; |
Yuchung Cheng | 8e4178c | 2012-07-19 06:43:08 +0000 | [diff] [blame] | 5687 | |
| 5688 | if (mss == tp->rx_opt.user_mss) { |
| 5689 | struct tcp_options_received opt; |
Yuchung Cheng | 8e4178c | 2012-07-19 06:43:08 +0000 | [diff] [blame] | 5690 | |
| 5691 | /* Get original SYNACK MSS value if user MSS sets mss_clamp */ |
| 5692 | tcp_clear_options(&opt); |
| 5693 | opt.user_mss = opt.mss_clamp = 0; |
Eric Dumazet | eed29f1 | 2017-06-07 10:34:36 -0700 | [diff] [blame] | 5694 | tcp_parse_options(sock_net(sk), synack, &opt, 0, NULL); |
Yuchung Cheng | 8e4178c | 2012-07-19 06:43:08 +0000 | [diff] [blame] | 5695 | mss = opt.mss_clamp; |
| 5696 | } |
| 5697 | |
Daniel Lee | 2646c83 | 2015-04-06 14:37:27 -0700 | [diff] [blame] | 5698 | if (!tp->syn_fastopen) { |
| 5699 | /* Ignore an unsolicited cookie */ |
Yuchung Cheng | 67da22d | 2012-07-19 06:43:11 +0000 | [diff] [blame] | 5700 | cookie->len = -1; |
Daniel Lee | 2646c83 | 2015-04-06 14:37:27 -0700 | [diff] [blame] | 5701 | } else if (tp->total_retrans) { |
| 5702 | /* SYN timed out and the SYN-ACK neither has a cookie nor |
| 5703 | * acknowledges data. Presumably the remote received only |
| 5704 | * the retransmitted (regular) SYNs: either the original |
| 5705 | * SYN-data or the corresponding SYN-ACK was dropped. |
| 5706 | */ |
| 5707 | syn_drop = (cookie->len < 0 && data); |
| 5708 | } else if (cookie->len < 0 && !tp->syn_data) { |
| 5709 | /* We requested a cookie but didn't get it. If we did not use |
| 5710 | * the (old) exp opt format then try so next time (try_exp=1). |
| 5711 | * Otherwise we go back to use the RFC7413 opt (try_exp=2). |
| 5712 | */ |
| 5713 | try_exp = tp->syn_fastopen_exp ? 2 : 1; |
| 5714 | } |
Yuchung Cheng | 67da22d | 2012-07-19 06:43:11 +0000 | [diff] [blame] | 5715 | |
Daniel Lee | 2646c83 | 2015-04-06 14:37:27 -0700 | [diff] [blame] | 5716 | tcp_fastopen_cache_set(sk, mss, cookie, syn_drop, try_exp); |
Yuchung Cheng | 8e4178c | 2012-07-19 06:43:08 +0000 | [diff] [blame] | 5717 | |
| 5718 | if (data) { /* Retransmit unacked data in SYN */ |
Eric Dumazet | 75c119a | 2017-10-05 22:21:27 -0700 | [diff] [blame] | 5719 | skb_rbtree_walk_from(data) { |
| 5720 | if (__tcp_retransmit_skb(sk, data, 1)) |
Yuchung Cheng | 93b174a | 2012-12-06 08:45:32 +0000 | [diff] [blame] | 5721 | break; |
| 5722 | } |
Yuchung Cheng | 8e4178c | 2012-07-19 06:43:08 +0000 | [diff] [blame] | 5723 | tcp_rearm_rto(sk); |
Eric Dumazet | c10d931 | 2016-04-29 14:16:47 -0700 | [diff] [blame] | 5724 | NET_INC_STATS(sock_net(sk), |
Eric Dumazet | 02a1d6e | 2016-04-27 16:44:39 -0700 | [diff] [blame] | 5725 | LINUX_MIB_TCPFASTOPENACTIVEFAIL); |
Yuchung Cheng | 8e4178c | 2012-07-19 06:43:08 +0000 | [diff] [blame] | 5726 | return true; |
| 5727 | } |
Yuchung Cheng | 6f73601 | 2012-10-19 15:14:44 +0000 | [diff] [blame] | 5728 | tp->syn_data_acked = tp->syn_data; |
Yuchung Cheng | bef5767 | 2018-04-17 23:18:46 -0700 | [diff] [blame] | 5729 | if (tp->syn_data_acked) { |
| 5730 | NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPFASTOPENACTIVE); |
| 5731 | /* SYN-data is counted as two separate packets in tcp_ack() */ |
| 5732 | if (tp->delivered > 1) |
| 5733 | --tp->delivered; |
| 5734 | } |
Eric Dumazet | 61d2bca | 2016-02-01 21:03:07 -0800 | [diff] [blame] | 5735 | |
| 5736 | tcp_fastopen_add_skb(sk, synack); |
| 5737 | |
Yuchung Cheng | 8e4178c | 2012-07-19 06:43:08 +0000 | [diff] [blame] | 5738 | return false; |
| 5739 | } |
| 5740 | |
Ursula Braun | 60e2a77 | 2017-10-25 11:01:45 +0200 | [diff] [blame] | 5741 | static void smc_check_reset_syn(struct tcp_sock *tp) |
| 5742 | { |
| 5743 | #if IS_ENABLED(CONFIG_SMC) |
| 5744 | if (static_branch_unlikely(&tcp_have_smc)) { |
| 5745 | if (tp->syn_smc && !tp->rx_opt.smc_ok) |
| 5746 | tp->syn_smc = 0; |
| 5747 | } |
| 5748 | #endif |
| 5749 | } |
| 5750 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5751 | static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb, |
Eric Dumazet | bda07a6 | 2015-09-29 07:42:40 -0700 | [diff] [blame] | 5752 | const struct tcphdr *th) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5753 | { |
Arnaldo Carvalho de Melo | d83d846 | 2005-12-13 23:26:10 -0800 | [diff] [blame] | 5754 | struct inet_connection_sock *icsk = inet_csk(sk); |
William Allen Simpson | 4957faade | 2009-12-02 18:25:27 +0000 | [diff] [blame] | 5755 | struct tcp_sock *tp = tcp_sk(sk); |
Yuchung Cheng | 8e4178c | 2012-07-19 06:43:08 +0000 | [diff] [blame] | 5756 | struct tcp_fastopen_cookie foc = { .len = -1 }; |
William Allen Simpson | 4957faade | 2009-12-02 18:25:27 +0000 | [diff] [blame] | 5757 | int saved_clamp = tp->rx_opt.mss_clamp; |
Eric Dumazet | 0f9fa83 | 2017-04-18 09:45:52 -0700 | [diff] [blame] | 5758 | bool fastopen_fail; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5759 | |
Eric Dumazet | eed29f1 | 2017-06-07 10:34:36 -0700 | [diff] [blame] | 5760 | tcp_parse_options(sock_net(sk), skb, &tp->rx_opt, 0, &foc); |
Andrew Vagin | e3e1202 | 2013-08-27 12:21:55 +0400 | [diff] [blame] | 5761 | if (tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr) |
Andrey Vagin | ee684b6 | 2013-02-11 05:50:19 +0000 | [diff] [blame] | 5762 | tp->rx_opt.rcv_tsecr -= tp->tsoffset; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5763 | |
| 5764 | if (th->ack) { |
| 5765 | /* rfc793: |
| 5766 | * "If the state is SYN-SENT then |
| 5767 | * first check the ACK bit |
| 5768 | * If the ACK bit is set |
| 5769 | * If SEG.ACK =< ISS, or SEG.ACK > SND.NXT, send |
| 5770 | * a reset (unless the RST bit is set, if so drop |
| 5771 | * the segment and return)" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5772 | */ |
Yuchung Cheng | 8e4178c | 2012-07-19 06:43:08 +0000 | [diff] [blame] | 5773 | if (!after(TCP_SKB_CB(skb)->ack_seq, tp->snd_una) || |
| 5774 | after(TCP_SKB_CB(skb)->ack_seq, tp->snd_nxt)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5775 | goto reset_and_undo; |
| 5776 | |
| 5777 | if (tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr && |
| 5778 | !between(tp->rx_opt.rcv_tsecr, tp->retrans_stamp, |
Eric Dumazet | 9a568de | 2017-05-16 14:00:14 -0700 | [diff] [blame] | 5779 | tcp_time_stamp(tp))) { |
Eric Dumazet | c10d931 | 2016-04-29 14:16:47 -0700 | [diff] [blame] | 5780 | NET_INC_STATS(sock_net(sk), |
Eric Dumazet | 02a1d6e | 2016-04-27 16:44:39 -0700 | [diff] [blame] | 5781 | LINUX_MIB_PAWSACTIVEREJECTED); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5782 | goto reset_and_undo; |
| 5783 | } |
| 5784 | |
| 5785 | /* Now ACK is acceptable. |
| 5786 | * |
| 5787 | * "If the RST bit is set |
| 5788 | * If the ACK was acceptable then signal the user "error: |
| 5789 | * connection reset", drop the segment, enter CLOSED state, |
| 5790 | * delete TCB, and return." |
| 5791 | */ |
| 5792 | |
| 5793 | if (th->rst) { |
| 5794 | tcp_reset(sk); |
| 5795 | goto discard; |
| 5796 | } |
| 5797 | |
| 5798 | /* rfc793: |
| 5799 | * "fifth, if neither of the SYN or RST bits is set then |
| 5800 | * drop the segment and return." |
| 5801 | * |
| 5802 | * See note below! |
| 5803 | * --ANK(990513) |
| 5804 | */ |
| 5805 | if (!th->syn) |
| 5806 | goto discard_and_undo; |
| 5807 | |
| 5808 | /* rfc793: |
| 5809 | * "If the SYN bit is on ... |
| 5810 | * are acceptable then ... |
| 5811 | * (our SYN has been ACKed), change the connection |
| 5812 | * state to ESTABLISHED..." |
| 5813 | */ |
| 5814 | |
Florian Westphal | 735d383 | 2014-09-29 13:08:30 +0200 | [diff] [blame] | 5815 | tcp_ecn_rcv_synack(tp, th); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5816 | |
Razvan Ghitulete | 1b3a692 | 2012-08-14 16:30:20 +0300 | [diff] [blame] | 5817 | tcp_init_wl(tp, TCP_SKB_CB(skb)->seq); |
Florian Westphal | 31770e3 | 2017-08-30 19:24:58 +0200 | [diff] [blame] | 5818 | tcp_ack(sk, skb, FLAG_SLOWPATH); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5819 | |
| 5820 | /* Ok.. it's good. Set up sequence numbers and |
| 5821 | * move to established. |
| 5822 | */ |
| 5823 | tp->rcv_nxt = TCP_SKB_CB(skb)->seq + 1; |
| 5824 | tp->rcv_wup = TCP_SKB_CB(skb)->seq + 1; |
| 5825 | |
| 5826 | /* RFC1323: The window in SYN & SYN/ACK segments is |
| 5827 | * never scaled. |
| 5828 | */ |
| 5829 | tp->snd_wnd = ntohs(th->window); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5830 | |
| 5831 | if (!tp->rx_opt.wscale_ok) { |
| 5832 | tp->rx_opt.snd_wscale = tp->rx_opt.rcv_wscale = 0; |
| 5833 | tp->window_clamp = min(tp->window_clamp, 65535U); |
| 5834 | } |
| 5835 | |
| 5836 | if (tp->rx_opt.saw_tstamp) { |
| 5837 | tp->rx_opt.tstamp_ok = 1; |
| 5838 | tp->tcp_header_len = |
| 5839 | sizeof(struct tcphdr) + TCPOLEN_TSTAMP_ALIGNED; |
| 5840 | tp->advmss -= TCPOLEN_TSTAMP_ALIGNED; |
| 5841 | tcp_store_ts_recent(tp); |
| 5842 | } else { |
| 5843 | tp->tcp_header_len = sizeof(struct tcphdr); |
| 5844 | } |
| 5845 | |
Arnaldo Carvalho de Melo | d83d846 | 2005-12-13 23:26:10 -0800 | [diff] [blame] | 5846 | tcp_sync_mss(sk, icsk->icsk_pmtu_cookie); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5847 | tcp_initialize_rcv_mss(sk); |
| 5848 | |
| 5849 | /* Remember, tcp_poll() does not lock socket! |
| 5850 | * Change state from SYN-SENT only after copied_seq |
| 5851 | * is initialized. */ |
| 5852 | tp->copied_seq = tp->rcv_nxt; |
William Allen Simpson | 4957faade | 2009-12-02 18:25:27 +0000 | [diff] [blame] | 5853 | |
Ursula Braun | 60e2a77 | 2017-10-25 11:01:45 +0200 | [diff] [blame] | 5854 | smc_check_reset_syn(tp); |
| 5855 | |
Ralf Baechle | e16aa20 | 2006-12-07 00:11:33 -0800 | [diff] [blame] | 5856 | smp_mb(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5857 | |
Pavel Emelyanov | 370816a | 2012-04-19 03:40:01 +0000 | [diff] [blame] | 5858 | tcp_finish_connect(sk, skb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5859 | |
Eric Dumazet | 0f9fa83 | 2017-04-18 09:45:52 -0700 | [diff] [blame] | 5860 | fastopen_fail = (tp->syn_fastopen || tp->syn_data) && |
| 5861 | tcp_rcv_fastopen_synack(sk, skb, &foc); |
Yuchung Cheng | 8e4178c | 2012-07-19 06:43:08 +0000 | [diff] [blame] | 5862 | |
Eric Dumazet | 0f9fa83 | 2017-04-18 09:45:52 -0700 | [diff] [blame] | 5863 | if (!sock_flag(sk, SOCK_DEAD)) { |
| 5864 | sk->sk_state_change(sk); |
| 5865 | sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT); |
| 5866 | } |
| 5867 | if (fastopen_fail) |
| 5868 | return -1; |
Arnaldo Carvalho de Melo | 295f732 | 2005-08-09 20:11:56 -0700 | [diff] [blame] | 5869 | if (sk->sk_write_pending || |
| 5870 | icsk->icsk_accept_queue.rskq_defer_accept || |
Wei Wang | 31954cd | 2019-01-25 10:53:19 -0800 | [diff] [blame] | 5871 | inet_csk_in_pingpong_mode(sk)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5872 | /* Save one ACK. Data will be ready after |
| 5873 | * several ticks, if write_pending is set. |
| 5874 | * |
| 5875 | * It may be deleted, but with this feature tcpdumps |
| 5876 | * look so _wonderfully_ clever, that I was not able |
| 5877 | * to stand against the temptation 8) --ANK |
| 5878 | */ |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 5879 | inet_csk_schedule_ack(sk); |
Eric Dumazet | 9a9c9b5 | 2018-05-21 15:08:56 -0700 | [diff] [blame] | 5880 | tcp_enter_quickack_mode(sk, TCP_MAX_QUICKACKS); |
Arnaldo Carvalho de Melo | 3f421ba | 2005-08-09 20:11:08 -0700 | [diff] [blame] | 5881 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, |
| 5882 | TCP_DELACK_MAX, TCP_RTO_MAX); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5883 | |
| 5884 | discard: |
Eric Dumazet | 532182c | 2016-04-01 08:52:19 -0700 | [diff] [blame] | 5885 | tcp_drop(sk, skb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5886 | return 0; |
| 5887 | } else { |
| 5888 | tcp_send_ack(sk); |
| 5889 | } |
| 5890 | return -1; |
| 5891 | } |
| 5892 | |
| 5893 | /* No ACK in the segment */ |
| 5894 | |
| 5895 | if (th->rst) { |
| 5896 | /* rfc793: |
| 5897 | * "If the RST bit is set |
| 5898 | * |
| 5899 | * Otherwise (no ACK) drop the segment and return." |
| 5900 | */ |
| 5901 | |
| 5902 | goto discard_and_undo; |
| 5903 | } |
| 5904 | |
| 5905 | /* PAWS check. */ |
Ilpo Järvinen | 056834d | 2007-12-31 14:57:14 -0800 | [diff] [blame] | 5906 | if (tp->rx_opt.ts_recent_stamp && tp->rx_opt.saw_tstamp && |
Ilpo Järvinen | c887e6d | 2009-03-14 14:23:03 +0000 | [diff] [blame] | 5907 | tcp_paws_reject(&tp->rx_opt, 0)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5908 | goto discard_and_undo; |
| 5909 | |
| 5910 | if (th->syn) { |
| 5911 | /* We see SYN without ACK. It is attempt of |
| 5912 | * simultaneous connect with crossed SYNs. |
| 5913 | * Particularly, it can be connect to self. |
| 5914 | */ |
| 5915 | tcp_set_state(sk, TCP_SYN_RECV); |
| 5916 | |
| 5917 | if (tp->rx_opt.saw_tstamp) { |
| 5918 | tp->rx_opt.tstamp_ok = 1; |
| 5919 | tcp_store_ts_recent(tp); |
| 5920 | tp->tcp_header_len = |
| 5921 | sizeof(struct tcphdr) + TCPOLEN_TSTAMP_ALIGNED; |
| 5922 | } else { |
| 5923 | tp->tcp_header_len = sizeof(struct tcphdr); |
| 5924 | } |
| 5925 | |
| 5926 | tp->rcv_nxt = TCP_SKB_CB(skb)->seq + 1; |
Eric Dumazet | 142a2e7 | 2015-11-26 08:18:14 -0800 | [diff] [blame] | 5927 | tp->copied_seq = tp->rcv_nxt; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5928 | tp->rcv_wup = TCP_SKB_CB(skb)->seq + 1; |
| 5929 | |
| 5930 | /* RFC1323: The window in SYN & SYN/ACK segments is |
| 5931 | * never scaled. |
| 5932 | */ |
| 5933 | tp->snd_wnd = ntohs(th->window); |
| 5934 | tp->snd_wl1 = TCP_SKB_CB(skb)->seq; |
| 5935 | tp->max_window = tp->snd_wnd; |
| 5936 | |
Florian Westphal | 735d383 | 2014-09-29 13:08:30 +0200 | [diff] [blame] | 5937 | tcp_ecn_rcv_syn(tp, th); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5938 | |
John Heffner | 5d424d5 | 2006-03-20 17:53:41 -0800 | [diff] [blame] | 5939 | tcp_mtup_init(sk); |
Arnaldo Carvalho de Melo | d83d846 | 2005-12-13 23:26:10 -0800 | [diff] [blame] | 5940 | tcp_sync_mss(sk, icsk->icsk_pmtu_cookie); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5941 | tcp_initialize_rcv_mss(sk); |
| 5942 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5943 | tcp_send_synack(sk); |
| 5944 | #if 0 |
| 5945 | /* Note, we could accept data and URG from this segment. |
Jerry Chu | 168a8f5 | 2012-08-31 12:29:13 +0000 | [diff] [blame] | 5946 | * There are no obstacles to make this (except that we must |
| 5947 | * either change tcp_recvmsg() to prevent it from returning data |
| 5948 | * before 3WHS completes per RFC793, or employ TCP Fast Open). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5949 | * |
| 5950 | * However, if we ignore data in ACKless segments sometimes, |
| 5951 | * we have no reasons to accept it sometimes. |
| 5952 | * Also, seems the code doing it in step6 of tcp_rcv_state_process |
| 5953 | * is not flawless. So, discard packet for sanity. |
| 5954 | * Uncomment this return to process the data. |
| 5955 | */ |
| 5956 | return -1; |
| 5957 | #else |
| 5958 | goto discard; |
| 5959 | #endif |
| 5960 | } |
| 5961 | /* "fifth, if neither of the SYN or RST bits is set then |
| 5962 | * drop the segment and return." |
| 5963 | */ |
| 5964 | |
| 5965 | discard_and_undo: |
| 5966 | tcp_clear_options(&tp->rx_opt); |
| 5967 | tp->rx_opt.mss_clamp = saved_clamp; |
| 5968 | goto discard; |
| 5969 | |
| 5970 | reset_and_undo: |
| 5971 | tcp_clear_options(&tp->rx_opt); |
| 5972 | tp->rx_opt.mss_clamp = saved_clamp; |
| 5973 | return 1; |
| 5974 | } |
| 5975 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5976 | /* |
| 5977 | * This function implements the receiving procedure of RFC 793 for |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 5978 | * all states except ESTABLISHED and TIME_WAIT. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5979 | * It's called from both tcp_v4_rcv and tcp_v6_rcv and should be |
| 5980 | * address independent. |
| 5981 | */ |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 5982 | |
Eric Dumazet | 72ab4a8 | 2015-09-29 07:42:41 -0700 | [diff] [blame] | 5983 | int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5984 | { |
| 5985 | struct tcp_sock *tp = tcp_sk(sk); |
Arnaldo Carvalho de Melo | 8292a17 | 2005-12-13 23:15:52 -0800 | [diff] [blame] | 5986 | struct inet_connection_sock *icsk = inet_csk(sk); |
Eric Dumazet | 72ab4a8 | 2015-09-29 07:42:41 -0700 | [diff] [blame] | 5987 | const struct tcphdr *th = tcp_hdr(skb); |
Jerry Chu | 168a8f5 | 2012-08-31 12:29:13 +0000 | [diff] [blame] | 5988 | struct request_sock *req; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5989 | int queued = 0; |
Eric Dumazet | 1f6afc8 | 2013-05-24 15:03:54 +0000 | [diff] [blame] | 5990 | bool acceptable; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5991 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5992 | switch (sk->sk_state) { |
| 5993 | case TCP_CLOSE: |
| 5994 | goto discard; |
| 5995 | |
| 5996 | case TCP_LISTEN: |
Stephen Hemminger | 2de979b | 2007-03-08 20:45:19 -0800 | [diff] [blame] | 5997 | if (th->ack) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5998 | return 1; |
| 5999 | |
Stephen Hemminger | 2de979b | 2007-03-08 20:45:19 -0800 | [diff] [blame] | 6000 | if (th->rst) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6001 | goto discard; |
| 6002 | |
Stephen Hemminger | 2de979b | 2007-03-08 20:45:19 -0800 | [diff] [blame] | 6003 | if (th->syn) { |
Eric Dumazet | fdf5af0 | 2011-12-02 23:41:42 +0000 | [diff] [blame] | 6004 | if (th->fin) |
| 6005 | goto discard; |
Eric Dumazet | 449809a | 2017-03-01 08:39:49 -0800 | [diff] [blame] | 6006 | /* It is possible that we process SYN packets from backlog, |
Eric Dumazet | 1ad98e9 | 2018-10-01 15:02:26 -0700 | [diff] [blame] | 6007 | * so we need to make sure to disable BH and RCU right there. |
Eric Dumazet | 449809a | 2017-03-01 08:39:49 -0800 | [diff] [blame] | 6008 | */ |
Eric Dumazet | 1ad98e9 | 2018-10-01 15:02:26 -0700 | [diff] [blame] | 6009 | rcu_read_lock(); |
Eric Dumazet | 449809a | 2017-03-01 08:39:49 -0800 | [diff] [blame] | 6010 | local_bh_disable(); |
| 6011 | acceptable = icsk->icsk_af_ops->conn_request(sk, skb) >= 0; |
| 6012 | local_bh_enable(); |
Eric Dumazet | 1ad98e9 | 2018-10-01 15:02:26 -0700 | [diff] [blame] | 6013 | rcu_read_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6014 | |
Eric Dumazet | 449809a | 2017-03-01 08:39:49 -0800 | [diff] [blame] | 6015 | if (!acceptable) |
| 6016 | return 1; |
Eric Dumazet | 0aea76d | 2016-04-21 22:13:01 -0700 | [diff] [blame] | 6017 | consume_skb(skb); |
Masayuki Nakagawa | fb7e239 | 2007-01-23 20:15:06 -0800 | [diff] [blame] | 6018 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6019 | } |
| 6020 | goto discard; |
| 6021 | |
| 6022 | case TCP_SYN_SENT: |
Eric Dumazet | 8804b27 | 2016-04-13 22:05:40 -0700 | [diff] [blame] | 6023 | tp->rx_opt.saw_tstamp = 0; |
Eric Dumazet | 9a568de | 2017-05-16 14:00:14 -0700 | [diff] [blame] | 6024 | tcp_mstamp_refresh(tp); |
Eric Dumazet | bda07a6 | 2015-09-29 07:42:40 -0700 | [diff] [blame] | 6025 | queued = tcp_rcv_synsent_state_process(sk, skb, th); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6026 | if (queued >= 0) |
| 6027 | return queued; |
| 6028 | |
| 6029 | /* Do step6 onward by hand. */ |
| 6030 | tcp_urg(sk, skb, th); |
| 6031 | __kfree_skb(skb); |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 6032 | tcp_data_snd_check(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6033 | return 0; |
| 6034 | } |
| 6035 | |
Eric Dumazet | 9a568de | 2017-05-16 14:00:14 -0700 | [diff] [blame] | 6036 | tcp_mstamp_refresh(tp); |
Eric Dumazet | 8804b27 | 2016-04-13 22:05:40 -0700 | [diff] [blame] | 6037 | tp->rx_opt.saw_tstamp = 0; |
Jerry Chu | 168a8f5 | 2012-08-31 12:29:13 +0000 | [diff] [blame] | 6038 | req = tp->fastopen_rsk; |
Ian Morris | 00db412 | 2015-04-03 09:17:27 +0100 | [diff] [blame] | 6039 | if (req) { |
Eric Dumazet | e0f9759 | 2018-02-13 06:14:12 -0800 | [diff] [blame] | 6040 | bool req_stolen; |
| 6041 | |
Jerry Chu | 37561f6 | 2012-10-22 11:26:36 +0000 | [diff] [blame] | 6042 | WARN_ON_ONCE(sk->sk_state != TCP_SYN_RECV && |
Jerry Chu | 168a8f5 | 2012-08-31 12:29:13 +0000 | [diff] [blame] | 6043 | sk->sk_state != TCP_FIN_WAIT1); |
| 6044 | |
Eric Dumazet | e0f9759 | 2018-02-13 06:14:12 -0800 | [diff] [blame] | 6045 | if (!tcp_check_req(sk, skb, req, true, &req_stolen)) |
Jerry Chu | 168a8f5 | 2012-08-31 12:29:13 +0000 | [diff] [blame] | 6046 | goto discard; |
Neal Cardwell | e69bebd | 2012-09-22 04:18:57 +0000 | [diff] [blame] | 6047 | } |
Eric Dumazet | c3ae62af | 2012-12-26 12:44:34 +0000 | [diff] [blame] | 6048 | |
Calvin Owens | 0c228e8 | 2014-11-20 15:09:53 -0800 | [diff] [blame] | 6049 | if (!th->ack && !th->rst && !th->syn) |
Eric Dumazet | c3ae62af | 2012-12-26 12:44:34 +0000 | [diff] [blame] | 6050 | goto discard; |
| 6051 | |
Neal Cardwell | e69bebd | 2012-09-22 04:18:57 +0000 | [diff] [blame] | 6052 | if (!tcp_validate_incoming(sk, skb, th, 0)) |
Eric Dumazet | 0c24604 | 2012-07-17 01:41:30 +0000 | [diff] [blame] | 6053 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6054 | |
| 6055 | /* step 5: check the ACK field */ |
Florian Westphal | 31770e3 | 2017-08-30 19:24:58 +0200 | [diff] [blame] | 6056 | acceptable = tcp_ack(sk, skb, FLAG_SLOWPATH | |
| 6057 | FLAG_UPDATE_TS_RECENT | |
Eric Dumazet | d0e1a1b | 2017-05-23 15:24:46 -0700 | [diff] [blame] | 6058 | FLAG_NO_CHALLENGE_ACK) > 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6059 | |
Eric Dumazet | d0e1a1b | 2017-05-23 15:24:46 -0700 | [diff] [blame] | 6060 | if (!acceptable) { |
| 6061 | if (sk->sk_state == TCP_SYN_RECV) |
| 6062 | return 1; /* send one RST */ |
| 6063 | tcp_send_challenge_ack(sk, skb); |
| 6064 | goto discard; |
| 6065 | } |
Eric Dumazet | 1f6afc8 | 2013-05-24 15:03:54 +0000 | [diff] [blame] | 6066 | switch (sk->sk_state) { |
| 6067 | case TCP_SYN_RECV: |
Yuchung Cheng | bef5767 | 2018-04-17 23:18:46 -0700 | [diff] [blame] | 6068 | tp->delivered++; /* SYN-ACK delivery isn't tracked in tcp_ack */ |
Yuchung Cheng | 0f1c28a | 2015-09-18 11:36:14 -0700 | [diff] [blame] | 6069 | if (!tp->srtt_us) |
| 6070 | tcp_synack_rtt_meas(sk, req); |
| 6071 | |
Joe Perches | 61eb9003 | 2013-05-24 18:36:13 +0000 | [diff] [blame] | 6072 | /* Once we leave TCP_SYN_RECV, we no longer need req |
| 6073 | * so release it. |
| 6074 | */ |
| 6075 | if (req) { |
Yuchung Cheng | 7e32b44 | 2016-09-21 16:16:15 -0700 | [diff] [blame] | 6076 | inet_csk(sk)->icsk_retransmits = 0; |
Joe Perches | 61eb9003 | 2013-05-24 18:36:13 +0000 | [diff] [blame] | 6077 | reqsk_fastopen_remove(sk, req, false); |
Wei Wang | 6d05081 | 2017-10-04 10:04:04 -0700 | [diff] [blame] | 6078 | /* Re-arm the timer because data may have been sent out. |
| 6079 | * This is similar to the regular data transmission case |
| 6080 | * when new data has just been ack'ed. |
| 6081 | * |
| 6082 | * (TFO) - we could try to be more aggressive and |
| 6083 | * retransmitting any data sooner based on when they |
| 6084 | * are sent out. |
| 6085 | */ |
| 6086 | tcp_rearm_rto(sk); |
Joe Perches | 61eb9003 | 2013-05-24 18:36:13 +0000 | [diff] [blame] | 6087 | } else { |
Wei Wang | 27204aa | 2017-10-04 10:03:44 -0700 | [diff] [blame] | 6088 | tcp_init_transfer(sk, BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB); |
Joe Perches | 61eb9003 | 2013-05-24 18:36:13 +0000 | [diff] [blame] | 6089 | tp->copied_seq = tp->rcv_nxt; |
Eric Dumazet | 1f6afc8 | 2013-05-24 15:03:54 +0000 | [diff] [blame] | 6090 | } |
Joe Perches | 61eb9003 | 2013-05-24 18:36:13 +0000 | [diff] [blame] | 6091 | smp_mb(); |
| 6092 | tcp_set_state(sk, TCP_ESTABLISHED); |
| 6093 | sk->sk_state_change(sk); |
| 6094 | |
| 6095 | /* Note, that this wakeup is only for marginal crossed SYN case. |
| 6096 | * Passively open sockets are not waked up, because |
| 6097 | * sk->sk_sleep == NULL and sk->sk_socket == NULL. |
| 6098 | */ |
| 6099 | if (sk->sk_socket) |
| 6100 | sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT); |
| 6101 | |
| 6102 | tp->snd_una = TCP_SKB_CB(skb)->ack_seq; |
| 6103 | tp->snd_wnd = ntohs(th->window) << tp->rx_opt.snd_wscale; |
| 6104 | tcp_init_wl(tp, TCP_SKB_CB(skb)->seq); |
| 6105 | |
| 6106 | if (tp->rx_opt.tstamp_ok) |
| 6107 | tp->advmss -= TCPOLEN_TSTAMP_ALIGNED; |
| 6108 | |
Yuchung Cheng | c040276 | 2016-09-19 23:39:21 -0400 | [diff] [blame] | 6109 | if (!inet_csk(sk)->icsk_ca_ops->cong_control) |
| 6110 | tcp_update_pacing_rate(sk); |
Neal Cardwell | 02cf4eb | 2013-10-21 15:40:19 -0400 | [diff] [blame] | 6111 | |
Joe Perches | 61eb9003 | 2013-05-24 18:36:13 +0000 | [diff] [blame] | 6112 | /* Prevent spurious tcp_cwnd_restart() on first data packet */ |
Eric Dumazet | d635fbe | 2017-05-16 14:00:03 -0700 | [diff] [blame] | 6113 | tp->lsndtime = tcp_jiffies32; |
Joe Perches | 61eb9003 | 2013-05-24 18:36:13 +0000 | [diff] [blame] | 6114 | |
| 6115 | tcp_initialize_rcv_mss(sk); |
Florian Westphal | 31770e3 | 2017-08-30 19:24:58 +0200 | [diff] [blame] | 6116 | tcp_fast_path_on(tp); |
Eric Dumazet | 1f6afc8 | 2013-05-24 15:03:54 +0000 | [diff] [blame] | 6117 | break; |
| 6118 | |
Joe Perches | c48b22d | 2013-05-24 18:06:58 +0000 | [diff] [blame] | 6119 | case TCP_FIN_WAIT1: { |
Joe Perches | c48b22d | 2013-05-24 18:06:58 +0000 | [diff] [blame] | 6120 | int tmo; |
| 6121 | |
Eric Dumazet | 1f6afc8 | 2013-05-24 15:03:54 +0000 | [diff] [blame] | 6122 | /* If we enter the TCP_FIN_WAIT1 state and we are a |
| 6123 | * Fast Open socket and this is the first acceptable |
| 6124 | * ACK we have received, this would have acknowledged |
| 6125 | * our SYNACK so stop the SYNACK timer. |
| 6126 | */ |
Ian Morris | 00db412 | 2015-04-03 09:17:27 +0100 | [diff] [blame] | 6127 | if (req) { |
Eric Dumazet | 1f6afc8 | 2013-05-24 15:03:54 +0000 | [diff] [blame] | 6128 | /* We no longer need the request sock. */ |
| 6129 | reqsk_fastopen_remove(sk, req, false); |
| 6130 | tcp_rearm_rto(sk); |
| 6131 | } |
Joe Perches | c48b22d | 2013-05-24 18:06:58 +0000 | [diff] [blame] | 6132 | if (tp->snd_una != tp->write_seq) |
| 6133 | break; |
Eric Dumazet | 1f6afc8 | 2013-05-24 15:03:54 +0000 | [diff] [blame] | 6134 | |
Joe Perches | c48b22d | 2013-05-24 18:06:58 +0000 | [diff] [blame] | 6135 | tcp_set_state(sk, TCP_FIN_WAIT2); |
| 6136 | sk->sk_shutdown |= SEND_SHUTDOWN; |
Eric Dumazet | 1f6afc8 | 2013-05-24 15:03:54 +0000 | [diff] [blame] | 6137 | |
Julian Anastasov | c3a2e83 | 2017-02-06 23:14:14 +0200 | [diff] [blame] | 6138 | sk_dst_confirm(sk); |
Eric Dumazet | 1f6afc8 | 2013-05-24 15:03:54 +0000 | [diff] [blame] | 6139 | |
Joe Perches | c48b22d | 2013-05-24 18:06:58 +0000 | [diff] [blame] | 6140 | if (!sock_flag(sk, SOCK_DEAD)) { |
| 6141 | /* Wake up lingering close() */ |
| 6142 | sk->sk_state_change(sk); |
| 6143 | break; |
| 6144 | } |
Eric Dumazet | 1f6afc8 | 2013-05-24 15:03:54 +0000 | [diff] [blame] | 6145 | |
Wei Wang | cf1ef3f | 2017-04-20 14:45:46 -0700 | [diff] [blame] | 6146 | if (tp->linger2 < 0) { |
| 6147 | tcp_done(sk); |
| 6148 | NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPABORTONDATA); |
| 6149 | return 1; |
| 6150 | } |
| 6151 | if (TCP_SKB_CB(skb)->end_seq != TCP_SKB_CB(skb)->seq && |
| 6152 | after(TCP_SKB_CB(skb)->end_seq - th->fin, tp->rcv_nxt)) { |
| 6153 | /* Receive out of order FIN after close() */ |
| 6154 | if (tp->syn_fastopen && th->fin) |
Wei Wang | 46c2fa3 | 2017-04-20 14:45:47 -0700 | [diff] [blame] | 6155 | tcp_fastopen_active_disable(sk); |
Joe Perches | c48b22d | 2013-05-24 18:06:58 +0000 | [diff] [blame] | 6156 | tcp_done(sk); |
Eric Dumazet | c10d931 | 2016-04-29 14:16:47 -0700 | [diff] [blame] | 6157 | NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPABORTONDATA); |
Joe Perches | c48b22d | 2013-05-24 18:06:58 +0000 | [diff] [blame] | 6158 | return 1; |
| 6159 | } |
Eric Dumazet | 1f6afc8 | 2013-05-24 15:03:54 +0000 | [diff] [blame] | 6160 | |
Joe Perches | c48b22d | 2013-05-24 18:06:58 +0000 | [diff] [blame] | 6161 | tmo = tcp_fin_time(sk); |
| 6162 | if (tmo > TCP_TIMEWAIT_LEN) { |
| 6163 | inet_csk_reset_keepalive_timer(sk, tmo - TCP_TIMEWAIT_LEN); |
| 6164 | } else if (th->fin || sock_owned_by_user(sk)) { |
| 6165 | /* Bad case. We could lose such FIN otherwise. |
| 6166 | * It is not a big problem, but it looks confusing |
| 6167 | * and not so rare event. We still can lose it now, |
| 6168 | * if it spins in bh_lock_sock(), but it is really |
| 6169 | * marginal case. |
| 6170 | */ |
| 6171 | inet_csk_reset_keepalive_timer(sk, tmo); |
| 6172 | } else { |
| 6173 | tcp_time_wait(sk, TCP_FIN_WAIT2, tmo); |
| 6174 | goto discard; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6175 | } |
Eric Dumazet | 1f6afc8 | 2013-05-24 15:03:54 +0000 | [diff] [blame] | 6176 | break; |
Joe Perches | c48b22d | 2013-05-24 18:06:58 +0000 | [diff] [blame] | 6177 | } |
Eric Dumazet | 1f6afc8 | 2013-05-24 15:03:54 +0000 | [diff] [blame] | 6178 | |
| 6179 | case TCP_CLOSING: |
| 6180 | if (tp->snd_una == tp->write_seq) { |
| 6181 | tcp_time_wait(sk, TCP_TIME_WAIT, 0); |
| 6182 | goto discard; |
| 6183 | } |
| 6184 | break; |
| 6185 | |
| 6186 | case TCP_LAST_ACK: |
| 6187 | if (tp->snd_una == tp->write_seq) { |
| 6188 | tcp_update_metrics(sk); |
| 6189 | tcp_done(sk); |
| 6190 | goto discard; |
| 6191 | } |
| 6192 | break; |
Eric Dumazet | c3ae62af | 2012-12-26 12:44:34 +0000 | [diff] [blame] | 6193 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6194 | |
| 6195 | /* step 6: check the URG bit */ |
| 6196 | tcp_urg(sk, skb, th); |
| 6197 | |
| 6198 | /* step 7: process the segment text */ |
| 6199 | switch (sk->sk_state) { |
| 6200 | case TCP_CLOSE_WAIT: |
| 6201 | case TCP_CLOSING: |
| 6202 | case TCP_LAST_ACK: |
| 6203 | if (!before(TCP_SKB_CB(skb)->seq, tp->rcv_nxt)) |
| 6204 | break; |
Gustavo A. R. Silva | fcfd6df | 2017-10-16 15:48:55 -0500 | [diff] [blame] | 6205 | /* fall through */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6206 | case TCP_FIN_WAIT1: |
| 6207 | case TCP_FIN_WAIT2: |
| 6208 | /* RFC 793 says to queue data in these states, |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 6209 | * RFC 1122 says we MUST send a reset. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6210 | * BSD 4.4 also does reset. |
| 6211 | */ |
| 6212 | if (sk->sk_shutdown & RCV_SHUTDOWN) { |
| 6213 | if (TCP_SKB_CB(skb)->end_seq != TCP_SKB_CB(skb)->seq && |
| 6214 | after(TCP_SKB_CB(skb)->end_seq - th->fin, tp->rcv_nxt)) { |
Eric Dumazet | c10d931 | 2016-04-29 14:16:47 -0700 | [diff] [blame] | 6215 | NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPABORTONDATA); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6216 | tcp_reset(sk); |
| 6217 | return 1; |
| 6218 | } |
| 6219 | } |
| 6220 | /* Fall through */ |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 6221 | case TCP_ESTABLISHED: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6222 | tcp_data_queue(sk, skb); |
| 6223 | queued = 1; |
| 6224 | break; |
| 6225 | } |
| 6226 | |
| 6227 | /* tcp_data could move socket to TIME-WAIT */ |
| 6228 | if (sk->sk_state != TCP_CLOSE) { |
Ilpo Järvinen | 9e412ba | 2007-04-20 22:18:02 -0700 | [diff] [blame] | 6229 | tcp_data_snd_check(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6230 | tcp_ack_snd_check(sk); |
| 6231 | } |
| 6232 | |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 6233 | if (!queued) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6234 | discard: |
Eric Dumazet | 532182c | 2016-04-01 08:52:19 -0700 | [diff] [blame] | 6235 | tcp_drop(sk, skb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6236 | } |
| 6237 | return 0; |
| 6238 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6239 | EXPORT_SYMBOL(tcp_rcv_state_process); |
Octavian Purdila | 1fb6f15 | 2014-06-25 17:10:02 +0300 | [diff] [blame] | 6240 | |
| 6241 | static inline void pr_drop_req(struct request_sock *req, __u16 port, int family) |
| 6242 | { |
| 6243 | struct inet_request_sock *ireq = inet_rsk(req); |
| 6244 | |
| 6245 | if (family == AF_INET) |
Joe Perches | ba7a46f | 2014-11-11 10:59:17 -0800 | [diff] [blame] | 6246 | net_dbg_ratelimited("drop open request from %pI4/%u\n", |
| 6247 | &ireq->ir_rmt_addr, port); |
Octavian Purdila | 4135ab8 | 2014-06-28 21:20:54 +0300 | [diff] [blame] | 6248 | #if IS_ENABLED(CONFIG_IPV6) |
| 6249 | else if (family == AF_INET6) |
Joe Perches | ba7a46f | 2014-11-11 10:59:17 -0800 | [diff] [blame] | 6250 | net_dbg_ratelimited("drop open request from %pI6/%u\n", |
| 6251 | &ireq->ir_v6_rmt_addr, port); |
Octavian Purdila | 4135ab8 | 2014-06-28 21:20:54 +0300 | [diff] [blame] | 6252 | #endif |
Octavian Purdila | 1fb6f15 | 2014-06-25 17:10:02 +0300 | [diff] [blame] | 6253 | } |
| 6254 | |
Florian Westphal | d82bd12 | 2014-09-29 13:08:29 +0200 | [diff] [blame] | 6255 | /* RFC3168 : 6.1.1 SYN packets must not have ECT/ECN bits set |
| 6256 | * |
| 6257 | * If we receive a SYN packet with these bits set, it means a |
| 6258 | * network is playing bad games with TOS bits. In order to |
| 6259 | * avoid possible false congestion notifications, we disable |
stephen hemminger | f4e715c | 2014-10-29 16:05:06 -0700 | [diff] [blame] | 6260 | * TCP ECN negotiation. |
Florian Westphal | d82bd12 | 2014-09-29 13:08:29 +0200 | [diff] [blame] | 6261 | * |
| 6262 | * Exception: tcp_ca wants ECN. This is required for DCTCP |
Florian Westphal | 843c2fd | 2015-01-30 20:45:20 +0100 | [diff] [blame] | 6263 | * congestion control: Linux DCTCP asserts ECT on all packets, |
| 6264 | * including SYN, which is most optimal solution; however, |
| 6265 | * others, such as FreeBSD do not. |
Florian Westphal | d82bd12 | 2014-09-29 13:08:29 +0200 | [diff] [blame] | 6266 | */ |
| 6267 | static void tcp_ecn_create_request(struct request_sock *req, |
| 6268 | const struct sk_buff *skb, |
Florian Westphal | f7b3bec | 2014-11-03 17:35:03 +0100 | [diff] [blame] | 6269 | const struct sock *listen_sk, |
| 6270 | const struct dst_entry *dst) |
Florian Westphal | d82bd12 | 2014-09-29 13:08:29 +0200 | [diff] [blame] | 6271 | { |
| 6272 | const struct tcphdr *th = tcp_hdr(skb); |
| 6273 | const struct net *net = sock_net(listen_sk); |
| 6274 | bool th_ecn = th->ece && th->cwr; |
Florian Westphal | 843c2fd | 2015-01-30 20:45:20 +0100 | [diff] [blame] | 6275 | bool ect, ecn_ok; |
Daniel Borkmann | c3a8d94 | 2015-08-31 15:58:47 +0200 | [diff] [blame] | 6276 | u32 ecn_ok_dst; |
Florian Westphal | d82bd12 | 2014-09-29 13:08:29 +0200 | [diff] [blame] | 6277 | |
| 6278 | if (!th_ecn) |
| 6279 | return; |
| 6280 | |
| 6281 | ect = !INET_ECN_is_not_ect(TCP_SKB_CB(skb)->ip_dsfield); |
Daniel Borkmann | c3a8d94 | 2015-08-31 15:58:47 +0200 | [diff] [blame] | 6282 | ecn_ok_dst = dst_feature(dst, DST_FEATURE_ECN_MASK); |
| 6283 | ecn_ok = net->ipv4.sysctl_tcp_ecn || ecn_ok_dst; |
Florian Westphal | d82bd12 | 2014-09-29 13:08:29 +0200 | [diff] [blame] | 6284 | |
Daniel Borkmann | c3a8d94 | 2015-08-31 15:58:47 +0200 | [diff] [blame] | 6285 | if ((!ect && ecn_ok) || tcp_ca_needs_ecn(listen_sk) || |
Lawrence Brakmo | 91b5b21 | 2017-06-30 20:02:49 -0700 | [diff] [blame] | 6286 | (ecn_ok_dst & DST_FEATURE_ECN_CA) || |
| 6287 | tcp_bpf_ca_needs_ecn((struct sock *)req)) |
Florian Westphal | d82bd12 | 2014-09-29 13:08:29 +0200 | [diff] [blame] | 6288 | inet_rsk(req)->ecn_ok = 1; |
| 6289 | } |
| 6290 | |
Eric Dumazet | 1bfc443 | 2015-03-16 21:06:19 -0700 | [diff] [blame] | 6291 | static void tcp_openreq_init(struct request_sock *req, |
| 6292 | const struct tcp_options_received *rx_opt, |
| 6293 | struct sk_buff *skb, const struct sock *sk) |
| 6294 | { |
| 6295 | struct inet_request_sock *ireq = inet_rsk(req); |
| 6296 | |
Eric Dumazet | ed53d0a | 2015-10-08 19:33:23 -0700 | [diff] [blame] | 6297 | req->rsk_rcv_wnd = 0; /* So that tcp_send_synack() knows! */ |
Eric Dumazet | 1bfc443 | 2015-03-16 21:06:19 -0700 | [diff] [blame] | 6298 | req->cookie_ts = 0; |
| 6299 | tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq; |
| 6300 | tcp_rsk(req)->rcv_nxt = TCP_SKB_CB(skb)->seq + 1; |
Eric Dumazet | 9a568de | 2017-05-16 14:00:14 -0700 | [diff] [blame] | 6301 | tcp_rsk(req)->snt_synack = tcp_clock_us(); |
Eric Dumazet | 1bfc443 | 2015-03-16 21:06:19 -0700 | [diff] [blame] | 6302 | tcp_rsk(req)->last_oow_ack_time = 0; |
| 6303 | req->mss = rx_opt->mss_clamp; |
| 6304 | req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0; |
| 6305 | ireq->tstamp_ok = rx_opt->tstamp_ok; |
| 6306 | ireq->sack_ok = rx_opt->sack_ok; |
| 6307 | ireq->snd_wscale = rx_opt->snd_wscale; |
| 6308 | ireq->wscale_ok = rx_opt->wscale_ok; |
| 6309 | ireq->acked = 0; |
| 6310 | ireq->ecn_ok = 0; |
| 6311 | ireq->ir_rmt_port = tcp_hdr(skb)->source; |
| 6312 | ireq->ir_num = ntohs(tcp_hdr(skb)->dest); |
| 6313 | ireq->ir_mark = inet_request_mark(sk, skb); |
Ursula Braun | 60e2a77 | 2017-10-25 11:01:45 +0200 | [diff] [blame] | 6314 | #if IS_ENABLED(CONFIG_SMC) |
| 6315 | ireq->smc_ok = rx_opt->smc_ok; |
| 6316 | #endif |
Eric Dumazet | 1bfc443 | 2015-03-16 21:06:19 -0700 | [diff] [blame] | 6317 | } |
| 6318 | |
Eric Dumazet | e49bb33 | 2015-03-17 18:32:27 -0700 | [diff] [blame] | 6319 | struct request_sock *inet_reqsk_alloc(const struct request_sock_ops *ops, |
Eric Dumazet | a1a5344 | 2015-10-04 21:08:11 -0700 | [diff] [blame] | 6320 | struct sock *sk_listener, |
| 6321 | bool attach_listener) |
Eric Dumazet | e49bb33 | 2015-03-17 18:32:27 -0700 | [diff] [blame] | 6322 | { |
Eric Dumazet | a1a5344 | 2015-10-04 21:08:11 -0700 | [diff] [blame] | 6323 | struct request_sock *req = reqsk_alloc(ops, sk_listener, |
| 6324 | attach_listener); |
Eric Dumazet | e49bb33 | 2015-03-17 18:32:27 -0700 | [diff] [blame] | 6325 | |
| 6326 | if (req) { |
| 6327 | struct inet_request_sock *ireq = inet_rsk(req); |
| 6328 | |
Eric Dumazet | c92e8c0 | 2017-10-20 09:04:13 -0700 | [diff] [blame] | 6329 | ireq->ireq_opt = NULL; |
Huw Davies | 56ac42b | 2016-06-27 15:05:28 -0400 | [diff] [blame] | 6330 | #if IS_ENABLED(CONFIG_IPV6) |
| 6331 | ireq->pktopts = NULL; |
| 6332 | #endif |
Yafang Shao | a06ac0d | 2018-04-24 23:07:45 +0800 | [diff] [blame] | 6333 | atomic64_set(&ireq->ir_cookie, 0); |
Eric Dumazet | e49bb33 | 2015-03-17 18:32:27 -0700 | [diff] [blame] | 6334 | ireq->ireq_state = TCP_NEW_SYN_RECV; |
| 6335 | write_pnet(&ireq->ireq_net, sock_net(sk_listener)); |
Eric Dumazet | 0144a81 | 2015-03-24 21:45:56 -0700 | [diff] [blame] | 6336 | ireq->ireq_family = sk_listener->sk_family; |
Eric Dumazet | e49bb33 | 2015-03-17 18:32:27 -0700 | [diff] [blame] | 6337 | } |
| 6338 | |
| 6339 | return req; |
| 6340 | } |
| 6341 | EXPORT_SYMBOL(inet_reqsk_alloc); |
| 6342 | |
Eric Dumazet | 41d25fe | 2015-03-25 15:08:47 -0700 | [diff] [blame] | 6343 | /* |
| 6344 | * Return true if a syncookie should be sent |
| 6345 | */ |
Eric Dumazet | 2985aaa | 2015-09-29 07:42:51 -0700 | [diff] [blame] | 6346 | static bool tcp_syn_flood_action(const struct sock *sk, |
Eric Dumazet | 41d25fe | 2015-03-25 15:08:47 -0700 | [diff] [blame] | 6347 | const struct sk_buff *skb, |
| 6348 | const char *proto) |
| 6349 | { |
Eric Dumazet | 8d2675f | 2015-10-02 11:43:25 -0700 | [diff] [blame] | 6350 | struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue; |
Eric Dumazet | 41d25fe | 2015-03-25 15:08:47 -0700 | [diff] [blame] | 6351 | const char *msg = "Dropping request"; |
| 6352 | bool want_cookie = false; |
Nikolay Borisov | 12ed824 | 2016-02-03 09:46:51 +0200 | [diff] [blame] | 6353 | struct net *net = sock_net(sk); |
Eric Dumazet | 41d25fe | 2015-03-25 15:08:47 -0700 | [diff] [blame] | 6354 | |
| 6355 | #ifdef CONFIG_SYN_COOKIES |
Nikolay Borisov | 12ed824 | 2016-02-03 09:46:51 +0200 | [diff] [blame] | 6356 | if (net->ipv4.sysctl_tcp_syncookies) { |
Eric Dumazet | 41d25fe | 2015-03-25 15:08:47 -0700 | [diff] [blame] | 6357 | msg = "Sending cookies"; |
| 6358 | want_cookie = true; |
Eric Dumazet | 02a1d6e | 2016-04-27 16:44:39 -0700 | [diff] [blame] | 6359 | __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPREQQFULLDOCOOKIES); |
Eric Dumazet | 41d25fe | 2015-03-25 15:08:47 -0700 | [diff] [blame] | 6360 | } else |
| 6361 | #endif |
Eric Dumazet | 02a1d6e | 2016-04-27 16:44:39 -0700 | [diff] [blame] | 6362 | __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPREQQFULLDROP); |
Eric Dumazet | 41d25fe | 2015-03-25 15:08:47 -0700 | [diff] [blame] | 6363 | |
Eric Dumazet | 8d2675f | 2015-10-02 11:43:25 -0700 | [diff] [blame] | 6364 | if (!queue->synflood_warned && |
Nikolay Borisov | 12ed824 | 2016-02-03 09:46:51 +0200 | [diff] [blame] | 6365 | net->ipv4.sysctl_tcp_syncookies != 2 && |
Eric Dumazet | 8d2675f | 2015-10-02 11:43:25 -0700 | [diff] [blame] | 6366 | xchg(&queue->synflood_warned, 1) == 0) |
Willem de Bruijn | 0297c1c | 2018-09-09 19:12:12 -0400 | [diff] [blame] | 6367 | net_info_ratelimited("%s: Possible SYN flooding on port %d. %s. Check SNMP counters.\n", |
| 6368 | proto, ntohs(tcp_hdr(skb)->dest), msg); |
Eric Dumazet | 2985aaa | 2015-09-29 07:42:51 -0700 | [diff] [blame] | 6369 | |
Eric Dumazet | 41d25fe | 2015-03-25 15:08:47 -0700 | [diff] [blame] | 6370 | return want_cookie; |
| 6371 | } |
| 6372 | |
Eric Dumazet | cd8ae85 | 2015-05-03 21:34:46 -0700 | [diff] [blame] | 6373 | static void tcp_reqsk_record_syn(const struct sock *sk, |
| 6374 | struct request_sock *req, |
| 6375 | const struct sk_buff *skb) |
| 6376 | { |
| 6377 | if (tcp_sk(sk)->save_syn) { |
| 6378 | u32 len = skb_network_header_len(skb) + tcp_hdrlen(skb); |
| 6379 | u32 *copy; |
| 6380 | |
| 6381 | copy = kmalloc(len + sizeof(u32), GFP_ATOMIC); |
| 6382 | if (copy) { |
| 6383 | copy[0] = len; |
| 6384 | memcpy(©[1], skb_network_header(skb), len); |
| 6385 | req->saved_syn = copy; |
| 6386 | } |
| 6387 | } |
| 6388 | } |
| 6389 | |
Octavian Purdila | 1fb6f15 | 2014-06-25 17:10:02 +0300 | [diff] [blame] | 6390 | int tcp_conn_request(struct request_sock_ops *rsk_ops, |
| 6391 | const struct tcp_request_sock_ops *af_ops, |
| 6392 | struct sock *sk, struct sk_buff *skb) |
| 6393 | { |
Octavian Purdila | 1fb6f15 | 2014-06-25 17:10:02 +0300 | [diff] [blame] | 6394 | struct tcp_fastopen_cookie foc = { .len = -1 }; |
Eric Dumazet | 7c85af8 | 2015-09-24 17:16:05 -0700 | [diff] [blame] | 6395 | __u32 isn = TCP_SKB_CB(skb)->tcp_tw_isn; |
| 6396 | struct tcp_options_received tmp_opt; |
| 6397 | struct tcp_sock *tp = tcp_sk(sk); |
Nikolay Borisov | 12ed824 | 2016-02-03 09:46:51 +0200 | [diff] [blame] | 6398 | struct net *net = sock_net(sk); |
Eric Dumazet | 7c85af8 | 2015-09-24 17:16:05 -0700 | [diff] [blame] | 6399 | struct sock *fastopen_sk = NULL; |
Eric Dumazet | 7c85af8 | 2015-09-24 17:16:05 -0700 | [diff] [blame] | 6400 | struct request_sock *req; |
| 6401 | bool want_cookie = false; |
Eric Dumazet | eaa72dc | 2017-08-29 15:16:01 -0700 | [diff] [blame] | 6402 | struct dst_entry *dst; |
Eric Dumazet | 7c85af8 | 2015-09-24 17:16:05 -0700 | [diff] [blame] | 6403 | struct flowi fl; |
Octavian Purdila | 1fb6f15 | 2014-06-25 17:10:02 +0300 | [diff] [blame] | 6404 | |
| 6405 | /* TW buckets are converted to open requests without |
| 6406 | * limitations, they conserve resources and peer is |
| 6407 | * evidently real one. |
| 6408 | */ |
Nikolay Borisov | 12ed824 | 2016-02-03 09:46:51 +0200 | [diff] [blame] | 6409 | if ((net->ipv4.sysctl_tcp_syncookies == 2 || |
Octavian Purdila | 1fb6f15 | 2014-06-25 17:10:02 +0300 | [diff] [blame] | 6410 | inet_csk_reqsk_queue_is_full(sk)) && !isn) { |
| 6411 | want_cookie = tcp_syn_flood_action(sk, skb, rsk_ops->slab_name); |
| 6412 | if (!want_cookie) |
| 6413 | goto drop; |
| 6414 | } |
| 6415 | |
Eric Dumazet | 5ea8ea2 | 2016-10-26 09:27:57 -0700 | [diff] [blame] | 6416 | if (sk_acceptq_is_full(sk)) { |
Eric Dumazet | c10d931 | 2016-04-29 14:16:47 -0700 | [diff] [blame] | 6417 | NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS); |
Octavian Purdila | 1fb6f15 | 2014-06-25 17:10:02 +0300 | [diff] [blame] | 6418 | goto drop; |
| 6419 | } |
| 6420 | |
Eric Dumazet | a1a5344 | 2015-10-04 21:08:11 -0700 | [diff] [blame] | 6421 | req = inet_reqsk_alloc(rsk_ops, sk, !want_cookie); |
Octavian Purdila | 1fb6f15 | 2014-06-25 17:10:02 +0300 | [diff] [blame] | 6422 | if (!req) |
| 6423 | goto drop; |
| 6424 | |
| 6425 | tcp_rsk(req)->af_specific = af_ops; |
Florian Westphal | 95a22ca | 2016-12-01 11:32:06 +0100 | [diff] [blame] | 6426 | tcp_rsk(req)->ts_off = 0; |
Octavian Purdila | 1fb6f15 | 2014-06-25 17:10:02 +0300 | [diff] [blame] | 6427 | |
| 6428 | tcp_clear_options(&tmp_opt); |
| 6429 | tmp_opt.mss_clamp = af_ops->mss_clamp; |
| 6430 | tmp_opt.user_mss = tp->rx_opt.user_mss; |
Eric Dumazet | eed29f1 | 2017-06-07 10:34:36 -0700 | [diff] [blame] | 6431 | tcp_parse_options(sock_net(sk), skb, &tmp_opt, 0, |
| 6432 | want_cookie ? NULL : &foc); |
Octavian Purdila | 1fb6f15 | 2014-06-25 17:10:02 +0300 | [diff] [blame] | 6433 | |
| 6434 | if (want_cookie && !tmp_opt.saw_tstamp) |
| 6435 | tcp_clear_options(&tmp_opt); |
| 6436 | |
Hans Wippel | bc58a1b | 2018-03-23 11:05:45 +0100 | [diff] [blame] | 6437 | if (IS_ENABLED(CONFIG_SMC) && want_cookie) |
| 6438 | tmp_opt.smc_ok = 0; |
| 6439 | |
Octavian Purdila | 1fb6f15 | 2014-06-25 17:10:02 +0300 | [diff] [blame] | 6440 | tmp_opt.tstamp_ok = tmp_opt.saw_tstamp; |
| 6441 | tcp_openreq_init(req, &tmp_opt, skb, sk); |
KOVACS Krisztian | 7a68257 | 2016-09-23 11:27:42 +0200 | [diff] [blame] | 6442 | inet_rsk(req)->no_srccheck = inet_sk(sk)->transparent; |
Octavian Purdila | 1fb6f15 | 2014-06-25 17:10:02 +0300 | [diff] [blame] | 6443 | |
Eric Dumazet | 16f8616 | 2015-03-13 15:51:10 -0700 | [diff] [blame] | 6444 | /* Note: tcp_v6_init_req() might override ir_iif for link locals */ |
David Ahern | 6dd9a14 | 2015-12-16 13:20:44 -0800 | [diff] [blame] | 6445 | inet_rsk(req)->ir_iif = inet_request_bound_dev_if(sk, skb); |
Eric Dumazet | 16f8616 | 2015-03-13 15:51:10 -0700 | [diff] [blame] | 6446 | |
Octavian Purdila | 1fb6f15 | 2014-06-25 17:10:02 +0300 | [diff] [blame] | 6447 | af_ops->init_req(req, sk, skb); |
| 6448 | |
| 6449 | if (security_inet_conn_request(sk, skb, req)) |
| 6450 | goto drop_and_free; |
| 6451 | |
Eric Dumazet | 84b114b | 2017-05-05 06:56:54 -0700 | [diff] [blame] | 6452 | if (tmp_opt.tstamp_ok) |
Eric Dumazet | 5d2ed05 | 2017-06-07 10:34:39 -0700 | [diff] [blame] | 6453 | tcp_rsk(req)->ts_off = af_ops->init_ts_off(net, skb); |
Florian Westphal | 95a22ca | 2016-12-01 11:32:06 +0100 | [diff] [blame] | 6454 | |
Tonghao Zhang | 49c7158 | 2017-08-21 23:33:48 -0700 | [diff] [blame] | 6455 | dst = af_ops->route_req(sk, &fl, req); |
| 6456 | if (!dst) |
| 6457 | goto drop_and_free; |
| 6458 | |
Florian Westphal | f7b3bec | 2014-11-03 17:35:03 +0100 | [diff] [blame] | 6459 | if (!want_cookie && !isn) { |
Octavian Purdila | 1fb6f15 | 2014-06-25 17:10:02 +0300 | [diff] [blame] | 6460 | /* Kill the following clause, if you dislike this way. */ |
Soheil Hassas Yeganeh | 4396e46 | 2017-03-15 16:30:46 -0400 | [diff] [blame] | 6461 | if (!net->ipv4.sysctl_tcp_syncookies && |
| 6462 | (net->ipv4.sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) < |
| 6463 | (net->ipv4.sysctl_max_syn_backlog >> 2)) && |
| 6464 | !tcp_peer_is_proven(req, dst)) { |
Octavian Purdila | 1fb6f15 | 2014-06-25 17:10:02 +0300 | [diff] [blame] | 6465 | /* Without syncookies last quarter of |
| 6466 | * backlog is filled with destinations, |
| 6467 | * proven to be alive. |
| 6468 | * It means that we continue to communicate |
| 6469 | * to destinations, already remembered |
| 6470 | * to the moment of synflood. |
| 6471 | */ |
| 6472 | pr_drop_req(req, ntohs(tcp_hdr(skb)->source), |
| 6473 | rsk_ops->family); |
| 6474 | goto drop_and_release; |
| 6475 | } |
| 6476 | |
Eric Dumazet | 84b114b | 2017-05-05 06:56:54 -0700 | [diff] [blame] | 6477 | isn = af_ops->init_seq(skb); |
Octavian Purdila | 1fb6f15 | 2014-06-25 17:10:02 +0300 | [diff] [blame] | 6478 | } |
Octavian Purdila | 1fb6f15 | 2014-06-25 17:10:02 +0300 | [diff] [blame] | 6479 | |
Florian Westphal | f7b3bec | 2014-11-03 17:35:03 +0100 | [diff] [blame] | 6480 | tcp_ecn_create_request(req, skb, sk, dst); |
| 6481 | |
| 6482 | if (want_cookie) { |
| 6483 | isn = cookie_init_sequence(af_ops, sk, skb, &req->mss); |
| 6484 | req->cookie_ts = tmp_opt.tstamp_ok; |
| 6485 | if (!tmp_opt.tstamp_ok) |
| 6486 | inet_rsk(req)->ecn_ok = 0; |
| 6487 | } |
| 6488 | |
Octavian Purdila | 1fb6f15 | 2014-06-25 17:10:02 +0300 | [diff] [blame] | 6489 | tcp_rsk(req)->snt_isn = isn; |
Eric Dumazet | 58d607d | 2015-09-15 15:24:20 -0700 | [diff] [blame] | 6490 | tcp_rsk(req)->txhash = net_tx_rndhash(); |
Octavian Purdila | 1fb6f15 | 2014-06-25 17:10:02 +0300 | [diff] [blame] | 6491 | tcp_openreq_init_rwin(req, sk, dst); |
Amritha Nambiar | c6345ce | 2018-06-29 21:26:57 -0700 | [diff] [blame] | 6492 | sk_rx_queue_set(req_to_sk(req), skb); |
Eric Dumazet | ca6fb06 | 2015-10-02 11:43:35 -0700 | [diff] [blame] | 6493 | if (!want_cookie) { |
Eric Dumazet | ca6fb06 | 2015-10-02 11:43:35 -0700 | [diff] [blame] | 6494 | tcp_reqsk_record_syn(sk, req, skb); |
Christoph Paasch | 71c0237 | 2017-10-23 13:22:23 -0700 | [diff] [blame] | 6495 | fastopen_sk = tcp_try_fastopen(sk, skb, req, &foc, dst); |
Eric Dumazet | ca6fb06 | 2015-10-02 11:43:35 -0700 | [diff] [blame] | 6496 | } |
Eric Dumazet | 7c85af8 | 2015-09-24 17:16:05 -0700 | [diff] [blame] | 6497 | if (fastopen_sk) { |
Eric Dumazet | ca6fb06 | 2015-10-02 11:43:35 -0700 | [diff] [blame] | 6498 | af_ops->send_synack(fastopen_sk, dst, &fl, req, |
Eric Dumazet | b3d0514 | 2016-04-13 22:05:39 -0700 | [diff] [blame] | 6499 | &foc, TCP_SYNACK_FASTOPEN); |
Eric Dumazet | 7656d84 | 2015-10-04 21:08:07 -0700 | [diff] [blame] | 6500 | /* Add the child socket directly into the accept queue */ |
Guillaume Nault | 9d3e136 | 2019-03-08 22:09:47 +0100 | [diff] [blame] | 6501 | if (!inet_csk_reqsk_queue_add(sk, req, fastopen_sk)) { |
| 6502 | reqsk_fastopen_remove(fastopen_sk, req, false); |
| 6503 | bh_unlock_sock(fastopen_sk); |
| 6504 | sock_put(fastopen_sk); |
| 6505 | reqsk_put(req); |
| 6506 | goto drop; |
| 6507 | } |
Eric Dumazet | 7656d84 | 2015-10-04 21:08:07 -0700 | [diff] [blame] | 6508 | sk->sk_data_ready(sk); |
| 6509 | bh_unlock_sock(fastopen_sk); |
Eric Dumazet | 7c85af8 | 2015-09-24 17:16:05 -0700 | [diff] [blame] | 6510 | sock_put(fastopen_sk); |
| 6511 | } else { |
Eric Dumazet | 9439ce0 | 2015-03-17 18:32:29 -0700 | [diff] [blame] | 6512 | tcp_rsk(req)->tfo_listener = false; |
Eric Dumazet | ca6fb06 | 2015-10-02 11:43:35 -0700 | [diff] [blame] | 6513 | if (!want_cookie) |
Lawrence Brakmo | 8550f32 | 2017-06-30 20:02:42 -0700 | [diff] [blame] | 6514 | inet_csk_reqsk_queue_hash_add(sk, req, |
| 6515 | tcp_timeout_init((struct sock *)req)); |
Eric Dumazet | b3d0514 | 2016-04-13 22:05:39 -0700 | [diff] [blame] | 6516 | af_ops->send_synack(sk, dst, &fl, req, &foc, |
| 6517 | !want_cookie ? TCP_SYNACK_NORMAL : |
| 6518 | TCP_SYNACK_COOKIE); |
Eric Dumazet | 9caad86 | 2016-04-01 08:52:20 -0700 | [diff] [blame] | 6519 | if (want_cookie) { |
| 6520 | reqsk_free(req); |
| 6521 | return 0; |
| 6522 | } |
Octavian Purdila | 1fb6f15 | 2014-06-25 17:10:02 +0300 | [diff] [blame] | 6523 | } |
Eric Dumazet | ca6fb06 | 2015-10-02 11:43:35 -0700 | [diff] [blame] | 6524 | reqsk_put(req); |
Octavian Purdila | 1fb6f15 | 2014-06-25 17:10:02 +0300 | [diff] [blame] | 6525 | return 0; |
| 6526 | |
| 6527 | drop_and_release: |
| 6528 | dst_release(dst); |
| 6529 | drop_and_free: |
| 6530 | reqsk_free(req); |
| 6531 | drop: |
Eric Dumazet | 9caad86 | 2016-04-01 08:52:20 -0700 | [diff] [blame] | 6532 | tcp_listendrop(sk); |
Octavian Purdila | 1fb6f15 | 2014-06-25 17:10:02 +0300 | [diff] [blame] | 6533 | return 0; |
| 6534 | } |
| 6535 | EXPORT_SYMBOL(tcp_conn_request); |