Arnaldo Carvalho de Melo | 7c65787 | 2005-08-09 20:14:34 -0700 | [diff] [blame] | 1 | /* |
| 2 | * net/dccp/timer.c |
| 3 | * |
| 4 | * An implementation of the DCCP protocol |
| 5 | * Arnaldo Carvalho de Melo <acme@conectiva.com.br> |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or |
| 8 | * modify it under the terms of the GNU General Public License |
| 9 | * as published by the Free Software Foundation; either version |
| 10 | * 2 of the License, or (at your option) any later version. |
| 11 | */ |
| 12 | |
| 13 | #include <linux/config.h> |
| 14 | #include <linux/dccp.h> |
| 15 | #include <linux/skbuff.h> |
| 16 | |
| 17 | #include "dccp.h" |
| 18 | |
| 19 | static void dccp_write_timer(unsigned long data); |
| 20 | static void dccp_keepalive_timer(unsigned long data); |
| 21 | static void dccp_delack_timer(unsigned long data); |
| 22 | |
| 23 | void dccp_init_xmit_timers(struct sock *sk) |
| 24 | { |
| 25 | inet_csk_init_xmit_timers(sk, &dccp_write_timer, &dccp_delack_timer, |
| 26 | &dccp_keepalive_timer); |
| 27 | } |
| 28 | |
| 29 | static void dccp_write_err(struct sock *sk) |
| 30 | { |
| 31 | sk->sk_err = sk->sk_err_soft ? : ETIMEDOUT; |
| 32 | sk->sk_error_report(sk); |
| 33 | |
| 34 | dccp_v4_send_reset(sk, DCCP_RESET_CODE_ABORTED); |
| 35 | dccp_done(sk); |
| 36 | DCCP_INC_STATS_BH(DCCP_MIB_ABORTONTIMEOUT); |
| 37 | } |
| 38 | |
| 39 | /* A write timeout has occurred. Process the after effects. */ |
| 40 | static int dccp_write_timeout(struct sock *sk) |
| 41 | { |
| 42 | const struct inet_connection_sock *icsk = inet_csk(sk); |
| 43 | int retry_until; |
| 44 | |
| 45 | if (sk->sk_state == DCCP_REQUESTING || sk->sk_state == DCCP_PARTOPEN) { |
| 46 | if (icsk->icsk_retransmits != 0) |
| 47 | dst_negative_advice(&sk->sk_dst_cache); |
Arnaldo Carvalho de Melo | 7690af3 | 2005-08-13 20:34:54 -0300 | [diff] [blame] | 48 | retry_until = icsk->icsk_syn_retries ? : |
| 49 | /* FIXME! */ 3 /* FIXME! sysctl_tcp_syn_retries */; |
Arnaldo Carvalho de Melo | 7c65787 | 2005-08-09 20:14:34 -0700 | [diff] [blame] | 50 | } else { |
Arnaldo Carvalho de Melo | 7690af3 | 2005-08-13 20:34:54 -0300 | [diff] [blame] | 51 | if (icsk->icsk_retransmits >= |
| 52 | /* FIXME! sysctl_tcp_retries1 */ 5 /* FIXME! */) { |
| 53 | /* NOTE. draft-ietf-tcpimpl-pmtud-01.txt requires pmtu |
| 54 | black hole detection. :-( |
Arnaldo Carvalho de Melo | 7c65787 | 2005-08-09 20:14:34 -0700 | [diff] [blame] | 55 | |
| 56 | It is place to make it. It is not made. I do not want |
| 57 | to make it. It is disguisting. It does not work in any |
| 58 | case. Let me to cite the same draft, which requires for |
| 59 | us to implement this: |
| 60 | |
| 61 | "The one security concern raised by this memo is that ICMP black holes |
| 62 | are often caused by over-zealous security administrators who block |
| 63 | all ICMP messages. It is vitally important that those who design and |
| 64 | deploy security systems understand the impact of strict filtering on |
| 65 | upper-layer protocols. The safest web site in the world is worthless |
| 66 | if most TCP implementations cannot transfer data from it. It would |
| 67 | be far nicer to have all of the black holes fixed rather than fixing |
| 68 | all of the TCP implementations." |
| 69 | |
| 70 | Golden words :-). |
| 71 | */ |
| 72 | |
| 73 | dst_negative_advice(&sk->sk_dst_cache); |
| 74 | } |
| 75 | |
| 76 | retry_until = /* FIXME! */ 15 /* FIXME! sysctl_tcp_retries2 */; |
| 77 | /* |
| 78 | * FIXME: see tcp_write_timout and tcp_out_of_resources |
| 79 | */ |
| 80 | } |
| 81 | |
| 82 | if (icsk->icsk_retransmits >= retry_until) { |
| 83 | /* Has it gone just too far? */ |
| 84 | dccp_write_err(sk); |
| 85 | return 1; |
| 86 | } |
| 87 | return 0; |
| 88 | } |
| 89 | |
| 90 | /* This is the same as tcp_delack_timer, sans prequeue & mem_reclaim stuff */ |
| 91 | static void dccp_delack_timer(unsigned long data) |
| 92 | { |
| 93 | struct sock *sk = (struct sock *)data; |
| 94 | struct inet_connection_sock *icsk = inet_csk(sk); |
| 95 | |
| 96 | bh_lock_sock(sk); |
| 97 | if (sock_owned_by_user(sk)) { |
| 98 | /* Try again later. */ |
| 99 | icsk->icsk_ack.blocked = 1; |
| 100 | NET_INC_STATS_BH(LINUX_MIB_DELAYEDACKLOCKED); |
Arnaldo Carvalho de Melo | 7690af3 | 2005-08-13 20:34:54 -0300 | [diff] [blame] | 101 | sk_reset_timer(sk, &icsk->icsk_delack_timer, |
| 102 | jiffies + TCP_DELACK_MIN); |
Arnaldo Carvalho de Melo | 7c65787 | 2005-08-09 20:14:34 -0700 | [diff] [blame] | 103 | goto out; |
| 104 | } |
| 105 | |
Arnaldo Carvalho de Melo | 7690af3 | 2005-08-13 20:34:54 -0300 | [diff] [blame] | 106 | if (sk->sk_state == DCCP_CLOSED || |
| 107 | !(icsk->icsk_ack.pending & ICSK_ACK_TIMER)) |
Arnaldo Carvalho de Melo | 7c65787 | 2005-08-09 20:14:34 -0700 | [diff] [blame] | 108 | goto out; |
| 109 | if (time_after(icsk->icsk_ack.timeout, jiffies)) { |
Arnaldo Carvalho de Melo | 7690af3 | 2005-08-13 20:34:54 -0300 | [diff] [blame] | 110 | sk_reset_timer(sk, &icsk->icsk_delack_timer, |
| 111 | icsk->icsk_ack.timeout); |
Arnaldo Carvalho de Melo | 7c65787 | 2005-08-09 20:14:34 -0700 | [diff] [blame] | 112 | goto out; |
| 113 | } |
| 114 | |
| 115 | icsk->icsk_ack.pending &= ~ICSK_ACK_TIMER; |
| 116 | |
| 117 | if (inet_csk_ack_scheduled(sk)) { |
| 118 | if (!icsk->icsk_ack.pingpong) { |
| 119 | /* Delayed ACK missed: inflate ATO. */ |
Arnaldo Carvalho de Melo | 7690af3 | 2005-08-13 20:34:54 -0300 | [diff] [blame] | 120 | icsk->icsk_ack.ato = min(icsk->icsk_ack.ato << 1, |
| 121 | icsk->icsk_rto); |
Arnaldo Carvalho de Melo | 7c65787 | 2005-08-09 20:14:34 -0700 | [diff] [blame] | 122 | } else { |
| 123 | /* Delayed ACK missed: leave pingpong mode and |
| 124 | * deflate ATO. |
| 125 | */ |
| 126 | icsk->icsk_ack.pingpong = 0; |
| 127 | icsk->icsk_ack.ato = TCP_ATO_MIN; |
| 128 | } |
| 129 | dccp_send_ack(sk); |
| 130 | NET_INC_STATS_BH(LINUX_MIB_DELAYEDACKS); |
| 131 | } |
| 132 | out: |
| 133 | bh_unlock_sock(sk); |
| 134 | sock_put(sk); |
| 135 | } |
| 136 | |
| 137 | /* |
| 138 | * The DCCP retransmit timer. |
| 139 | */ |
| 140 | static void dccp_retransmit_timer(struct sock *sk) |
| 141 | { |
| 142 | struct inet_connection_sock *icsk = inet_csk(sk); |
| 143 | |
| 144 | /* |
| 145 | * sk->sk_send_head has to have one skb with |
| 146 | * DCCP_SKB_CB(skb)->dccpd_type set to one of the retransmittable DCCP |
Arnaldo Carvalho de Melo | 03ace39 | 2005-08-21 05:36:45 -0300 | [diff] [blame] | 147 | * packet types (REQUEST, RESPONSE, the ACK in the 3way handshake |
Arnaldo Carvalho de Melo | 7c65787 | 2005-08-09 20:14:34 -0700 | [diff] [blame] | 148 | * (PARTOPEN timer), etc). |
| 149 | */ |
| 150 | BUG_TRAP(sk->sk_send_head != NULL); |
| 151 | |
| 152 | /* |
| 153 | * More than than 4MSL (8 minutes) has passed, a RESET(aborted) was |
| 154 | * sent, no need to retransmit, this sock is dead. |
| 155 | */ |
| 156 | if (dccp_write_timeout(sk)) |
| 157 | goto out; |
| 158 | |
| 159 | /* |
| 160 | * We want to know the number of packets retransmitted, not the |
| 161 | * total number of retransmissions of clones of original packets. |
| 162 | */ |
| 163 | if (icsk->icsk_retransmits == 0) |
| 164 | DCCP_INC_STATS_BH(DCCP_MIB_TIMEOUTS); |
| 165 | |
| 166 | if (dccp_retransmit_skb(sk, sk->sk_send_head) < 0) { |
| 167 | /* |
| 168 | * Retransmission failed because of local congestion, |
| 169 | * do not backoff. |
| 170 | */ |
| 171 | if (icsk->icsk_retransmits == 0) |
| 172 | icsk->icsk_retransmits = 1; |
| 173 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, |
| 174 | min(icsk->icsk_rto, |
| 175 | TCP_RESOURCE_PROBE_INTERVAL), |
Arnaldo Carvalho de Melo | 7690af3 | 2005-08-13 20:34:54 -0300 | [diff] [blame] | 176 | DCCP_RTO_MAX); |
Arnaldo Carvalho de Melo | 7c65787 | 2005-08-09 20:14:34 -0700 | [diff] [blame] | 177 | goto out; |
| 178 | } |
| 179 | |
| 180 | icsk->icsk_backoff++; |
| 181 | icsk->icsk_retransmits++; |
| 182 | |
| 183 | icsk->icsk_rto = min(icsk->icsk_rto << 1, DCCP_RTO_MAX); |
Arnaldo Carvalho de Melo | 7690af3 | 2005-08-13 20:34:54 -0300 | [diff] [blame] | 184 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, icsk->icsk_rto, |
| 185 | DCCP_RTO_MAX); |
Arnaldo Carvalho de Melo | 7c65787 | 2005-08-09 20:14:34 -0700 | [diff] [blame] | 186 | if (icsk->icsk_retransmits > 3 /* FIXME: sysctl_dccp_retries1 */) |
| 187 | __sk_dst_reset(sk); |
| 188 | out:; |
| 189 | } |
| 190 | |
| 191 | static void dccp_write_timer(unsigned long data) |
| 192 | { |
| 193 | struct sock *sk = (struct sock *)data; |
| 194 | struct inet_connection_sock *icsk = inet_csk(sk); |
| 195 | int event = 0; |
| 196 | |
| 197 | bh_lock_sock(sk); |
| 198 | if (sock_owned_by_user(sk)) { |
| 199 | /* Try again later */ |
Arnaldo Carvalho de Melo | 7690af3 | 2005-08-13 20:34:54 -0300 | [diff] [blame] | 200 | sk_reset_timer(sk, &icsk->icsk_retransmit_timer, |
| 201 | jiffies + (HZ / 20)); |
Arnaldo Carvalho de Melo | 7c65787 | 2005-08-09 20:14:34 -0700 | [diff] [blame] | 202 | goto out; |
| 203 | } |
| 204 | |
| 205 | if (sk->sk_state == DCCP_CLOSED || !icsk->icsk_pending) |
| 206 | goto out; |
| 207 | |
| 208 | if (time_after(icsk->icsk_timeout, jiffies)) { |
Arnaldo Carvalho de Melo | 7690af3 | 2005-08-13 20:34:54 -0300 | [diff] [blame] | 209 | sk_reset_timer(sk, &icsk->icsk_retransmit_timer, |
| 210 | icsk->icsk_timeout); |
Arnaldo Carvalho de Melo | 7c65787 | 2005-08-09 20:14:34 -0700 | [diff] [blame] | 211 | goto out; |
| 212 | } |
| 213 | |
| 214 | event = icsk->icsk_pending; |
| 215 | icsk->icsk_pending = 0; |
| 216 | |
| 217 | switch (event) { |
| 218 | case ICSK_TIME_RETRANS: |
| 219 | dccp_retransmit_timer(sk); |
| 220 | break; |
| 221 | } |
| 222 | out: |
| 223 | bh_unlock_sock(sk); |
| 224 | sock_put(sk); |
| 225 | } |
| 226 | |
| 227 | /* |
| 228 | * Timer for listening sockets |
| 229 | */ |
| 230 | static void dccp_response_timer(struct sock *sk) |
| 231 | { |
Arnaldo Carvalho de Melo | 7690af3 | 2005-08-13 20:34:54 -0300 | [diff] [blame] | 232 | inet_csk_reqsk_queue_prune(sk, TCP_SYNQ_INTERVAL, DCCP_TIMEOUT_INIT, |
| 233 | DCCP_RTO_MAX); |
Arnaldo Carvalho de Melo | 7c65787 | 2005-08-09 20:14:34 -0700 | [diff] [blame] | 234 | } |
| 235 | |
| 236 | static void dccp_keepalive_timer(unsigned long data) |
| 237 | { |
| 238 | struct sock *sk = (struct sock *)data; |
| 239 | |
| 240 | /* Only process if socket is not in use. */ |
| 241 | bh_lock_sock(sk); |
| 242 | if (sock_owned_by_user(sk)) { |
| 243 | /* Try again later. */ |
| 244 | inet_csk_reset_keepalive_timer(sk, HZ / 20); |
| 245 | goto out; |
| 246 | } |
| 247 | |
| 248 | if (sk->sk_state == DCCP_LISTEN) { |
| 249 | dccp_response_timer(sk); |
| 250 | goto out; |
| 251 | } |
| 252 | out: |
| 253 | bh_unlock_sock(sk); |
| 254 | sock_put(sk); |
| 255 | } |