| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * DCCP connection tracking protocol helper |
| * |
| * Copyright (c) 2005, 2006, 2008 Patrick McHardy <kaber@trash.net> |
| */ |
| #include <linux/kernel.h> |
| #include <linux/init.h> |
| #include <linux/sysctl.h> |
| #include <linux/spinlock.h> |
| #include <linux/skbuff.h> |
| #include <linux/dccp.h> |
| #include <linux/slab.h> |
| |
| #include <net/net_namespace.h> |
| #include <net/netns/generic.h> |
| |
| #include <linux/netfilter/nfnetlink_conntrack.h> |
| #include <net/netfilter/nf_conntrack.h> |
| #include <net/netfilter/nf_conntrack_l4proto.h> |
| #include <net/netfilter/nf_conntrack_ecache.h> |
| #include <net/netfilter/nf_conntrack_timeout.h> |
| #include <net/netfilter/nf_log.h> |
| |
| /* Timeouts are based on values from RFC4340: |
| * |
| * - REQUEST: |
| * |
| * 8.1.2. Client Request |
| * |
| * A client MAY give up on its DCCP-Requests after some time |
| * (3 minutes, for example). |
| * |
| * - RESPOND: |
| * |
| * 8.1.3. Server Response |
| * |
| * It MAY also leave the RESPOND state for CLOSED after a timeout of |
| * not less than 4MSL (8 minutes); |
| * |
| * - PARTOPEN: |
| * |
| * 8.1.5. Handshake Completion |
| * |
| * If the client remains in PARTOPEN for more than 4MSL (8 minutes), |
| * it SHOULD reset the connection with Reset Code 2, "Aborted". |
| * |
| * - OPEN: |
| * |
| * The DCCP timestamp overflows after 11.9 hours. If the connection |
| * stays idle this long the sequence number won't be recognized |
| * as valid anymore. |
| * |
| * - CLOSEREQ/CLOSING: |
| * |
| * 8.3. Termination |
| * |
| * The retransmission timer should initially be set to go off in two |
| * round-trip times and should back off to not less than once every |
| * 64 seconds ... |
| * |
| * - TIMEWAIT: |
| * |
| * 4.3. States |
| * |
| * A server or client socket remains in this state for 2MSL (4 minutes) |
| * after the connection has been town down, ... |
| */ |
| |
| #define DCCP_MSL (2 * 60 * HZ) |
| |
| #ifdef CONFIG_NF_CONNTRACK_PROCFS |
| static const char * const dccp_state_names[] = { |
| [CT_DCCP_NONE] = "NONE", |
| [CT_DCCP_REQUEST] = "REQUEST", |
| [CT_DCCP_RESPOND] = "RESPOND", |
| [CT_DCCP_PARTOPEN] = "PARTOPEN", |
| [CT_DCCP_OPEN] = "OPEN", |
| [CT_DCCP_CLOSEREQ] = "CLOSEREQ", |
| [CT_DCCP_CLOSING] = "CLOSING", |
| [CT_DCCP_TIMEWAIT] = "TIMEWAIT", |
| [CT_DCCP_IGNORE] = "IGNORE", |
| [CT_DCCP_INVALID] = "INVALID", |
| }; |
| #endif |
| |
| #define sNO CT_DCCP_NONE |
| #define sRQ CT_DCCP_REQUEST |
| #define sRS CT_DCCP_RESPOND |
| #define sPO CT_DCCP_PARTOPEN |
| #define sOP CT_DCCP_OPEN |
| #define sCR CT_DCCP_CLOSEREQ |
| #define sCG CT_DCCP_CLOSING |
| #define sTW CT_DCCP_TIMEWAIT |
| #define sIG CT_DCCP_IGNORE |
| #define sIV CT_DCCP_INVALID |
| |
| /* |
| * DCCP state transition table |
| * |
| * The assumption is the same as for TCP tracking: |
| * |
| * We are the man in the middle. All the packets go through us but might |
| * get lost in transit to the destination. It is assumed that the destination |
| * can't receive segments we haven't seen. |
| * |
| * The following states exist: |
| * |
| * NONE: Initial state, expecting Request |
| * REQUEST: Request seen, waiting for Response from server |
| * RESPOND: Response from server seen, waiting for Ack from client |
| * PARTOPEN: Ack after Response seen, waiting for packet other than Response, |
| * Reset or Sync from server |
| * OPEN: Packet other than Response, Reset or Sync seen |
| * CLOSEREQ: CloseReq from server seen, expecting Close from client |
| * CLOSING: Close seen, expecting Reset |
| * TIMEWAIT: Reset seen |
| * IGNORE: Not determinable whether packet is valid |
| * |
| * Some states exist only on one side of the connection: REQUEST, RESPOND, |
| * PARTOPEN, CLOSEREQ. For the other side these states are equivalent to |
| * the one it was in before. |
| * |
| * Packets are marked as ignored (sIG) if we don't know if they're valid |
| * (for example a reincarnation of a connection we didn't notice is dead |
| * already) and the server may send back a connection closing Reset or a |
| * Response. They're also used for Sync/SyncAck packets, which we don't |
| * care about. |
| */ |
| static const u_int8_t |
| dccp_state_table[CT_DCCP_ROLE_MAX + 1][DCCP_PKT_SYNCACK + 1][CT_DCCP_MAX + 1] = { |
| [CT_DCCP_ROLE_CLIENT] = { |
| [DCCP_PKT_REQUEST] = { |
| /* |
| * sNO -> sRQ Regular Request |
| * sRQ -> sRQ Retransmitted Request or reincarnation |
| * sRS -> sRS Retransmitted Request (apparently Response |
| * got lost after we saw it) or reincarnation |
| * sPO -> sIG Ignore, conntrack might be out of sync |
| * sOP -> sIG Ignore, conntrack might be out of sync |
| * sCR -> sIG Ignore, conntrack might be out of sync |
| * sCG -> sIG Ignore, conntrack might be out of sync |
| * sTW -> sRQ Reincarnation |
| * |
| * sNO, sRQ, sRS, sPO. sOP, sCR, sCG, sTW, */ |
| sRQ, sRQ, sRS, sIG, sIG, sIG, sIG, sRQ, |
| }, |
| [DCCP_PKT_RESPONSE] = { |
| /* |
| * sNO -> sIV Invalid |
| * sRQ -> sIG Ignore, might be response to ignored Request |
| * sRS -> sIG Ignore, might be response to ignored Request |
| * sPO -> sIG Ignore, might be response to ignored Request |
| * sOP -> sIG Ignore, might be response to ignored Request |
| * sCR -> sIG Ignore, might be response to ignored Request |
| * sCG -> sIG Ignore, might be response to ignored Request |
| * sTW -> sIV Invalid, reincarnation in reverse direction |
| * goes through sRQ |
| * |
| * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
| sIV, sIG, sIG, sIG, sIG, sIG, sIG, sIV, |
| }, |
| [DCCP_PKT_ACK] = { |
| /* |
| * sNO -> sIV No connection |
| * sRQ -> sIV No connection |
| * sRS -> sPO Ack for Response, move to PARTOPEN (8.1.5.) |
| * sPO -> sPO Retransmitted Ack for Response, remain in PARTOPEN |
| * sOP -> sOP Regular ACK, remain in OPEN |
| * sCR -> sCR Ack in CLOSEREQ MAY be processed (8.3.) |
| * sCG -> sCG Ack in CLOSING MAY be processed (8.3.) |
| * sTW -> sIV |
| * |
| * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
| sIV, sIV, sPO, sPO, sOP, sCR, sCG, sIV |
| }, |
| [DCCP_PKT_DATA] = { |
| /* |
| * sNO -> sIV No connection |
| * sRQ -> sIV No connection |
| * sRS -> sIV No connection |
| * sPO -> sIV MUST use DataAck in PARTOPEN state (8.1.5.) |
| * sOP -> sOP Regular Data packet |
| * sCR -> sCR Data in CLOSEREQ MAY be processed (8.3.) |
| * sCG -> sCG Data in CLOSING MAY be processed (8.3.) |
| * sTW -> sIV |
| * |
| * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
| sIV, sIV, sIV, sIV, sOP, sCR, sCG, sIV, |
| }, |
| [DCCP_PKT_DATAACK] = { |
| /* |
| * sNO -> sIV No connection |
| * sRQ -> sIV No connection |
| * sRS -> sPO Ack for Response, move to PARTOPEN (8.1.5.) |
| * sPO -> sPO Remain in PARTOPEN state |
| * sOP -> sOP Regular DataAck packet in OPEN state |
| * sCR -> sCR DataAck in CLOSEREQ MAY be processed (8.3.) |
| * sCG -> sCG DataAck in CLOSING MAY be processed (8.3.) |
| * sTW -> sIV |
| * |
| * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
| sIV, sIV, sPO, sPO, sOP, sCR, sCG, sIV |
| }, |
| [DCCP_PKT_CLOSEREQ] = { |
| /* |
| * CLOSEREQ may only be sent by the server. |
| * |
| * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
| sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV |
| }, |
| [DCCP_PKT_CLOSE] = { |
| /* |
| * sNO -> sIV No connection |
| * sRQ -> sIV No connection |
| * sRS -> sIV No connection |
| * sPO -> sCG Client-initiated close |
| * sOP -> sCG Client-initiated close |
| * sCR -> sCG Close in response to CloseReq (8.3.) |
| * sCG -> sCG Retransmit |
| * sTW -> sIV Late retransmit, already in TIME_WAIT |
| * |
| * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
| sIV, sIV, sIV, sCG, sCG, sCG, sIV, sIV |
| }, |
| [DCCP_PKT_RESET] = { |
| /* |
| * sNO -> sIV No connection |
| * sRQ -> sTW Sync received or timeout, SHOULD send Reset (8.1.1.) |
| * sRS -> sTW Response received without Request |
| * sPO -> sTW Timeout, SHOULD send Reset (8.1.5.) |
| * sOP -> sTW Connection reset |
| * sCR -> sTW Connection reset |
| * sCG -> sTW Connection reset |
| * sTW -> sIG Ignore (don't refresh timer) |
| * |
| * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
| sIV, sTW, sTW, sTW, sTW, sTW, sTW, sIG |
| }, |
| [DCCP_PKT_SYNC] = { |
| /* |
| * We currently ignore Sync packets |
| * |
| * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
| sIV, sIG, sIG, sIG, sIG, sIG, sIG, sIG, |
| }, |
| [DCCP_PKT_SYNCACK] = { |
| /* |
| * We currently ignore SyncAck packets |
| * |
| * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
| sIV, sIG, sIG, sIG, sIG, sIG, sIG, sIG, |
| }, |
| }, |
| [CT_DCCP_ROLE_SERVER] = { |
| [DCCP_PKT_REQUEST] = { |
| /* |
| * sNO -> sIV Invalid |
| * sRQ -> sIG Ignore, conntrack might be out of sync |
| * sRS -> sIG Ignore, conntrack might be out of sync |
| * sPO -> sIG Ignore, conntrack might be out of sync |
| * sOP -> sIG Ignore, conntrack might be out of sync |
| * sCR -> sIG Ignore, conntrack might be out of sync |
| * sCG -> sIG Ignore, conntrack might be out of sync |
| * sTW -> sRQ Reincarnation, must reverse roles |
| * |
| * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
| sIV, sIG, sIG, sIG, sIG, sIG, sIG, sRQ |
| }, |
| [DCCP_PKT_RESPONSE] = { |
| /* |
| * sNO -> sIV Response without Request |
| * sRQ -> sRS Response to clients Request |
| * sRS -> sRS Retransmitted Response (8.1.3. SHOULD NOT) |
| * sPO -> sIG Response to an ignored Request or late retransmit |
| * sOP -> sIG Ignore, might be response to ignored Request |
| * sCR -> sIG Ignore, might be response to ignored Request |
| * sCG -> sIG Ignore, might be response to ignored Request |
| * sTW -> sIV Invalid, Request from client in sTW moves to sRQ |
| * |
| * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
| sIV, sRS, sRS, sIG, sIG, sIG, sIG, sIV |
| }, |
| [DCCP_PKT_ACK] = { |
| /* |
| * sNO -> sIV No connection |
| * sRQ -> sIV No connection |
| * sRS -> sIV No connection |
| * sPO -> sOP Enter OPEN state (8.1.5.) |
| * sOP -> sOP Regular Ack in OPEN state |
| * sCR -> sIV Waiting for Close from client |
| * sCG -> sCG Ack in CLOSING MAY be processed (8.3.) |
| * sTW -> sIV |
| * |
| * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
| sIV, sIV, sIV, sOP, sOP, sIV, sCG, sIV |
| }, |
| [DCCP_PKT_DATA] = { |
| /* |
| * sNO -> sIV No connection |
| * sRQ -> sIV No connection |
| * sRS -> sIV No connection |
| * sPO -> sOP Enter OPEN state (8.1.5.) |
| * sOP -> sOP Regular Data packet in OPEN state |
| * sCR -> sIV Waiting for Close from client |
| * sCG -> sCG Data in CLOSING MAY be processed (8.3.) |
| * sTW -> sIV |
| * |
| * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
| sIV, sIV, sIV, sOP, sOP, sIV, sCG, sIV |
| }, |
| [DCCP_PKT_DATAACK] = { |
| /* |
| * sNO -> sIV No connection |
| * sRQ -> sIV No connection |
| * sRS -> sIV No connection |
| * sPO -> sOP Enter OPEN state (8.1.5.) |
| * sOP -> sOP Regular DataAck in OPEN state |
| * sCR -> sIV Waiting for Close from client |
| * sCG -> sCG Data in CLOSING MAY be processed (8.3.) |
| * sTW -> sIV |
| * |
| * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
| sIV, sIV, sIV, sOP, sOP, sIV, sCG, sIV |
| }, |
| [DCCP_PKT_CLOSEREQ] = { |
| /* |
| * sNO -> sIV No connection |
| * sRQ -> sIV No connection |
| * sRS -> sIV No connection |
| * sPO -> sOP -> sCR Move directly to CLOSEREQ (8.1.5.) |
| * sOP -> sCR CloseReq in OPEN state |
| * sCR -> sCR Retransmit |
| * sCG -> sCR Simultaneous close, client sends another Close |
| * sTW -> sIV Already closed |
| * |
| * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
| sIV, sIV, sIV, sCR, sCR, sCR, sCR, sIV |
| }, |
| [DCCP_PKT_CLOSE] = { |
| /* |
| * sNO -> sIV No connection |
| * sRQ -> sIV No connection |
| * sRS -> sIV No connection |
| * sPO -> sOP -> sCG Move direcly to CLOSING |
| * sOP -> sCG Move to CLOSING |
| * sCR -> sIV Close after CloseReq is invalid |
| * sCG -> sCG Retransmit |
| * sTW -> sIV Already closed |
| * |
| * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
| sIV, sIV, sIV, sCG, sCG, sIV, sCG, sIV |
| }, |
| [DCCP_PKT_RESET] = { |
| /* |
| * sNO -> sIV No connection |
| * sRQ -> sTW Reset in response to Request |
| * sRS -> sTW Timeout, SHOULD send Reset (8.1.3.) |
| * sPO -> sTW Timeout, SHOULD send Reset (8.1.3.) |
| * sOP -> sTW |
| * sCR -> sTW |
| * sCG -> sTW |
| * sTW -> sIG Ignore (don't refresh timer) |
| * |
| * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW, sTW */ |
| sIV, sTW, sTW, sTW, sTW, sTW, sTW, sTW, sIG |
| }, |
| [DCCP_PKT_SYNC] = { |
| /* |
| * We currently ignore Sync packets |
| * |
| * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
| sIV, sIG, sIG, sIG, sIG, sIG, sIG, sIG, |
| }, |
| [DCCP_PKT_SYNCACK] = { |
| /* |
| * We currently ignore SyncAck packets |
| * |
| * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
| sIV, sIG, sIG, sIG, sIG, sIG, sIG, sIG, |
| }, |
| }, |
| }; |
| |
| static noinline bool |
| dccp_new(struct nf_conn *ct, const struct sk_buff *skb, |
| const struct dccp_hdr *dh, |
| const struct nf_hook_state *hook_state) |
| { |
| struct net *net = nf_ct_net(ct); |
| struct nf_dccp_net *dn; |
| const char *msg; |
| u_int8_t state; |
| |
| state = dccp_state_table[CT_DCCP_ROLE_CLIENT][dh->dccph_type][CT_DCCP_NONE]; |
| switch (state) { |
| default: |
| dn = nf_dccp_pernet(net); |
| if (dn->dccp_loose == 0) { |
| msg = "not picking up existing connection "; |
| goto out_invalid; |
| } |
| break; |
| case CT_DCCP_REQUEST: |
| break; |
| case CT_DCCP_INVALID: |
| msg = "invalid state transition "; |
| goto out_invalid; |
| } |
| |
| ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_CLIENT; |
| ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_SERVER; |
| ct->proto.dccp.state = CT_DCCP_NONE; |
| ct->proto.dccp.last_pkt = DCCP_PKT_REQUEST; |
| ct->proto.dccp.last_dir = IP_CT_DIR_ORIGINAL; |
| ct->proto.dccp.handshake_seq = 0; |
| return true; |
| |
| out_invalid: |
| nf_ct_l4proto_log_invalid(skb, ct, hook_state, "%s", msg); |
| return false; |
| } |
| |
| static u64 dccp_ack_seq(const struct dccp_hdr *dh) |
| { |
| const struct dccp_hdr_ack_bits *dhack; |
| |
| dhack = (void *)dh + __dccp_basic_hdr_len(dh); |
| return ((u64)ntohs(dhack->dccph_ack_nr_high) << 32) + |
| ntohl(dhack->dccph_ack_nr_low); |
| } |
| |
| static bool dccp_error(const struct dccp_hdr *dh, |
| struct sk_buff *skb, unsigned int dataoff, |
| const struct nf_hook_state *state) |
| { |
| static const unsigned long require_seq48 = 1 << DCCP_PKT_REQUEST | |
| 1 << DCCP_PKT_RESPONSE | |
| 1 << DCCP_PKT_CLOSEREQ | |
| 1 << DCCP_PKT_CLOSE | |
| 1 << DCCP_PKT_RESET | |
| 1 << DCCP_PKT_SYNC | |
| 1 << DCCP_PKT_SYNCACK; |
| unsigned int dccp_len = skb->len - dataoff; |
| unsigned int cscov; |
| const char *msg; |
| u8 type; |
| |
| BUILD_BUG_ON(DCCP_PKT_INVALID >= BITS_PER_LONG); |
| |
| if (dh->dccph_doff * 4 < sizeof(struct dccp_hdr) || |
| dh->dccph_doff * 4 > dccp_len) { |
| msg = "nf_ct_dccp: truncated/malformed packet "; |
| goto out_invalid; |
| } |
| |
| cscov = dccp_len; |
| if (dh->dccph_cscov) { |
| cscov = (dh->dccph_cscov - 1) * 4; |
| if (cscov > dccp_len) { |
| msg = "nf_ct_dccp: bad checksum coverage "; |
| goto out_invalid; |
| } |
| } |
| |
| if (state->hook == NF_INET_PRE_ROUTING && |
| state->net->ct.sysctl_checksum && |
| nf_checksum_partial(skb, state->hook, dataoff, cscov, |
| IPPROTO_DCCP, state->pf)) { |
| msg = "nf_ct_dccp: bad checksum "; |
| goto out_invalid; |
| } |
| |
| type = dh->dccph_type; |
| if (type >= DCCP_PKT_INVALID) { |
| msg = "nf_ct_dccp: reserved packet type "; |
| goto out_invalid; |
| } |
| |
| if (test_bit(type, &require_seq48) && !dh->dccph_x) { |
| msg = "nf_ct_dccp: type lacks 48bit sequence numbers"; |
| goto out_invalid; |
| } |
| |
| return false; |
| out_invalid: |
| nf_l4proto_log_invalid(skb, state, IPPROTO_DCCP, "%s", msg); |
| return true; |
| } |
| |
| struct nf_conntrack_dccp_buf { |
| struct dccp_hdr dh; /* generic header part */ |
| struct dccp_hdr_ext ext; /* optional depending dh->dccph_x */ |
| union { /* depends on header type */ |
| struct dccp_hdr_ack_bits ack; |
| struct dccp_hdr_request req; |
| struct dccp_hdr_response response; |
| struct dccp_hdr_reset rst; |
| } u; |
| }; |
| |
| static struct dccp_hdr * |
| dccp_header_pointer(const struct sk_buff *skb, int offset, const struct dccp_hdr *dh, |
| struct nf_conntrack_dccp_buf *buf) |
| { |
| unsigned int hdrlen = __dccp_hdr_len(dh); |
| |
| if (hdrlen > sizeof(*buf)) |
| return NULL; |
| |
| return skb_header_pointer(skb, offset, hdrlen, buf); |
| } |
| |
| int nf_conntrack_dccp_packet(struct nf_conn *ct, struct sk_buff *skb, |
| unsigned int dataoff, |
| enum ip_conntrack_info ctinfo, |
| const struct nf_hook_state *state) |
| { |
| enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); |
| struct nf_conntrack_dccp_buf _dh; |
| u_int8_t type, old_state, new_state; |
| enum ct_dccp_roles role; |
| unsigned int *timeouts; |
| struct dccp_hdr *dh; |
| |
| dh = skb_header_pointer(skb, dataoff, sizeof(*dh), &_dh.dh); |
| if (!dh) |
| return -NF_ACCEPT; |
| |
| if (dccp_error(dh, skb, dataoff, state)) |
| return -NF_ACCEPT; |
| |
| /* pull again, including possible 48 bit sequences and subtype header */ |
| dh = dccp_header_pointer(skb, dataoff, dh, &_dh); |
| if (!dh) |
| return -NF_ACCEPT; |
| |
| type = dh->dccph_type; |
| if (!nf_ct_is_confirmed(ct) && !dccp_new(ct, skb, dh, state)) |
| return -NF_ACCEPT; |
| |
| if (type == DCCP_PKT_RESET && |
| !test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) { |
| /* Tear down connection immediately if only reply is a RESET */ |
| nf_ct_kill_acct(ct, ctinfo, skb); |
| return NF_ACCEPT; |
| } |
| |
| spin_lock_bh(&ct->lock); |
| |
| role = ct->proto.dccp.role[dir]; |
| old_state = ct->proto.dccp.state; |
| new_state = dccp_state_table[role][type][old_state]; |
| |
| switch (new_state) { |
| case CT_DCCP_REQUEST: |
| if (old_state == CT_DCCP_TIMEWAIT && |
| role == CT_DCCP_ROLE_SERVER) { |
| /* Reincarnation in the reverse direction: reopen and |
| * reverse client/server roles. */ |
| ct->proto.dccp.role[dir] = CT_DCCP_ROLE_CLIENT; |
| ct->proto.dccp.role[!dir] = CT_DCCP_ROLE_SERVER; |
| } |
| break; |
| case CT_DCCP_RESPOND: |
| if (old_state == CT_DCCP_REQUEST) |
| ct->proto.dccp.handshake_seq = dccp_hdr_seq(dh); |
| break; |
| case CT_DCCP_PARTOPEN: |
| if (old_state == CT_DCCP_RESPOND && |
| type == DCCP_PKT_ACK && |
| dccp_ack_seq(dh) == ct->proto.dccp.handshake_seq) |
| set_bit(IPS_ASSURED_BIT, &ct->status); |
| break; |
| case CT_DCCP_IGNORE: |
| /* |
| * Connection tracking might be out of sync, so we ignore |
| * packets that might establish a new connection and resync |
| * if the server responds with a valid Response. |
| */ |
| if (ct->proto.dccp.last_dir == !dir && |
| ct->proto.dccp.last_pkt == DCCP_PKT_REQUEST && |
| type == DCCP_PKT_RESPONSE) { |
| ct->proto.dccp.role[!dir] = CT_DCCP_ROLE_CLIENT; |
| ct->proto.dccp.role[dir] = CT_DCCP_ROLE_SERVER; |
| ct->proto.dccp.handshake_seq = dccp_hdr_seq(dh); |
| new_state = CT_DCCP_RESPOND; |
| break; |
| } |
| ct->proto.dccp.last_dir = dir; |
| ct->proto.dccp.last_pkt = type; |
| |
| spin_unlock_bh(&ct->lock); |
| nf_ct_l4proto_log_invalid(skb, ct, state, "%s", "invalid packet"); |
| return NF_ACCEPT; |
| case CT_DCCP_INVALID: |
| spin_unlock_bh(&ct->lock); |
| nf_ct_l4proto_log_invalid(skb, ct, state, "%s", "invalid state transition"); |
| return -NF_ACCEPT; |
| } |
| |
| ct->proto.dccp.last_dir = dir; |
| ct->proto.dccp.last_pkt = type; |
| ct->proto.dccp.state = new_state; |
| spin_unlock_bh(&ct->lock); |
| |
| if (new_state != old_state) |
| nf_conntrack_event_cache(IPCT_PROTOINFO, ct); |
| |
| timeouts = nf_ct_timeout_lookup(ct); |
| if (!timeouts) |
| timeouts = nf_dccp_pernet(nf_ct_net(ct))->dccp_timeout; |
| nf_ct_refresh_acct(ct, ctinfo, skb, timeouts[new_state]); |
| |
| return NF_ACCEPT; |
| } |
| |
| static bool dccp_can_early_drop(const struct nf_conn *ct) |
| { |
| switch (ct->proto.dccp.state) { |
| case CT_DCCP_CLOSEREQ: |
| case CT_DCCP_CLOSING: |
| case CT_DCCP_TIMEWAIT: |
| return true; |
| default: |
| break; |
| } |
| |
| return false; |
| } |
| |
| #ifdef CONFIG_NF_CONNTRACK_PROCFS |
| static void dccp_print_conntrack(struct seq_file *s, struct nf_conn *ct) |
| { |
| seq_printf(s, "%s ", dccp_state_names[ct->proto.dccp.state]); |
| } |
| #endif |
| |
| #if IS_ENABLED(CONFIG_NF_CT_NETLINK) |
| static int dccp_to_nlattr(struct sk_buff *skb, struct nlattr *nla, |
| struct nf_conn *ct, bool destroy) |
| { |
| struct nlattr *nest_parms; |
| |
| spin_lock_bh(&ct->lock); |
| nest_parms = nla_nest_start(skb, CTA_PROTOINFO_DCCP); |
| if (!nest_parms) |
| goto nla_put_failure; |
| if (nla_put_u8(skb, CTA_PROTOINFO_DCCP_STATE, ct->proto.dccp.state)) |
| goto nla_put_failure; |
| |
| if (destroy) |
| goto skip_state; |
| |
| if (nla_put_u8(skb, CTA_PROTOINFO_DCCP_ROLE, |
| ct->proto.dccp.role[IP_CT_DIR_ORIGINAL]) || |
| nla_put_be64(skb, CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ, |
| cpu_to_be64(ct->proto.dccp.handshake_seq), |
| CTA_PROTOINFO_DCCP_PAD)) |
| goto nla_put_failure; |
| skip_state: |
| nla_nest_end(skb, nest_parms); |
| spin_unlock_bh(&ct->lock); |
| |
| return 0; |
| |
| nla_put_failure: |
| spin_unlock_bh(&ct->lock); |
| return -1; |
| } |
| |
| static const struct nla_policy dccp_nla_policy[CTA_PROTOINFO_DCCP_MAX + 1] = { |
| [CTA_PROTOINFO_DCCP_STATE] = { .type = NLA_U8 }, |
| [CTA_PROTOINFO_DCCP_ROLE] = { .type = NLA_U8 }, |
| [CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ] = { .type = NLA_U64 }, |
| [CTA_PROTOINFO_DCCP_PAD] = { .type = NLA_UNSPEC }, |
| }; |
| |
| #define DCCP_NLATTR_SIZE ( \ |
| NLA_ALIGN(NLA_HDRLEN + 1) + \ |
| NLA_ALIGN(NLA_HDRLEN + 1) + \ |
| NLA_ALIGN(NLA_HDRLEN + sizeof(u64)) + \ |
| NLA_ALIGN(NLA_HDRLEN + 0)) |
| |
| static int nlattr_to_dccp(struct nlattr *cda[], struct nf_conn *ct) |
| { |
| struct nlattr *attr = cda[CTA_PROTOINFO_DCCP]; |
| struct nlattr *tb[CTA_PROTOINFO_DCCP_MAX + 1]; |
| int err; |
| |
| if (!attr) |
| return 0; |
| |
| err = nla_parse_nested_deprecated(tb, CTA_PROTOINFO_DCCP_MAX, attr, |
| dccp_nla_policy, NULL); |
| if (err < 0) |
| return err; |
| |
| if (!tb[CTA_PROTOINFO_DCCP_STATE] || |
| !tb[CTA_PROTOINFO_DCCP_ROLE] || |
| nla_get_u8(tb[CTA_PROTOINFO_DCCP_ROLE]) > CT_DCCP_ROLE_MAX || |
| nla_get_u8(tb[CTA_PROTOINFO_DCCP_STATE]) >= CT_DCCP_IGNORE) { |
| return -EINVAL; |
| } |
| |
| spin_lock_bh(&ct->lock); |
| ct->proto.dccp.state = nla_get_u8(tb[CTA_PROTOINFO_DCCP_STATE]); |
| if (nla_get_u8(tb[CTA_PROTOINFO_DCCP_ROLE]) == CT_DCCP_ROLE_CLIENT) { |
| ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_CLIENT; |
| ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_SERVER; |
| } else { |
| ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_SERVER; |
| ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_CLIENT; |
| } |
| if (tb[CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ]) { |
| ct->proto.dccp.handshake_seq = |
| be64_to_cpu(nla_get_be64(tb[CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ])); |
| } |
| spin_unlock_bh(&ct->lock); |
| return 0; |
| } |
| #endif |
| |
| #ifdef CONFIG_NF_CONNTRACK_TIMEOUT |
| |
| #include <linux/netfilter/nfnetlink.h> |
| #include <linux/netfilter/nfnetlink_cttimeout.h> |
| |
| static int dccp_timeout_nlattr_to_obj(struct nlattr *tb[], |
| struct net *net, void *data) |
| { |
| struct nf_dccp_net *dn = nf_dccp_pernet(net); |
| unsigned int *timeouts = data; |
| int i; |
| |
| if (!timeouts) |
| timeouts = dn->dccp_timeout; |
| |
| /* set default DCCP timeouts. */ |
| for (i=0; i<CT_DCCP_MAX; i++) |
| timeouts[i] = dn->dccp_timeout[i]; |
| |
| /* there's a 1:1 mapping between attributes and protocol states. */ |
| for (i=CTA_TIMEOUT_DCCP_UNSPEC+1; i<CTA_TIMEOUT_DCCP_MAX+1; i++) { |
| if (tb[i]) { |
| timeouts[i] = ntohl(nla_get_be32(tb[i])) * HZ; |
| } |
| } |
| |
| timeouts[CTA_TIMEOUT_DCCP_UNSPEC] = timeouts[CTA_TIMEOUT_DCCP_REQUEST]; |
| return 0; |
| } |
| |
| static int |
| dccp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data) |
| { |
| const unsigned int *timeouts = data; |
| int i; |
| |
| for (i=CTA_TIMEOUT_DCCP_UNSPEC+1; i<CTA_TIMEOUT_DCCP_MAX+1; i++) { |
| if (nla_put_be32(skb, i, htonl(timeouts[i] / HZ))) |
| goto nla_put_failure; |
| } |
| return 0; |
| |
| nla_put_failure: |
| return -ENOSPC; |
| } |
| |
| static const struct nla_policy |
| dccp_timeout_nla_policy[CTA_TIMEOUT_DCCP_MAX+1] = { |
| [CTA_TIMEOUT_DCCP_REQUEST] = { .type = NLA_U32 }, |
| [CTA_TIMEOUT_DCCP_RESPOND] = { .type = NLA_U32 }, |
| [CTA_TIMEOUT_DCCP_PARTOPEN] = { .type = NLA_U32 }, |
| [CTA_TIMEOUT_DCCP_OPEN] = { .type = NLA_U32 }, |
| [CTA_TIMEOUT_DCCP_CLOSEREQ] = { .type = NLA_U32 }, |
| [CTA_TIMEOUT_DCCP_CLOSING] = { .type = NLA_U32 }, |
| [CTA_TIMEOUT_DCCP_TIMEWAIT] = { .type = NLA_U32 }, |
| }; |
| #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */ |
| |
| void nf_conntrack_dccp_init_net(struct net *net) |
| { |
| struct nf_dccp_net *dn = nf_dccp_pernet(net); |
| |
| /* default values */ |
| dn->dccp_loose = 1; |
| dn->dccp_timeout[CT_DCCP_REQUEST] = 2 * DCCP_MSL; |
| dn->dccp_timeout[CT_DCCP_RESPOND] = 4 * DCCP_MSL; |
| dn->dccp_timeout[CT_DCCP_PARTOPEN] = 4 * DCCP_MSL; |
| dn->dccp_timeout[CT_DCCP_OPEN] = 12 * 3600 * HZ; |
| dn->dccp_timeout[CT_DCCP_CLOSEREQ] = 64 * HZ; |
| dn->dccp_timeout[CT_DCCP_CLOSING] = 64 * HZ; |
| dn->dccp_timeout[CT_DCCP_TIMEWAIT] = 2 * DCCP_MSL; |
| |
| /* timeouts[0] is unused, make it same as SYN_SENT so |
| * ->timeouts[0] contains 'new' timeout, like udp or icmp. |
| */ |
| dn->dccp_timeout[CT_DCCP_NONE] = dn->dccp_timeout[CT_DCCP_REQUEST]; |
| } |
| |
| const struct nf_conntrack_l4proto nf_conntrack_l4proto_dccp = { |
| .l4proto = IPPROTO_DCCP, |
| .can_early_drop = dccp_can_early_drop, |
| #ifdef CONFIG_NF_CONNTRACK_PROCFS |
| .print_conntrack = dccp_print_conntrack, |
| #endif |
| #if IS_ENABLED(CONFIG_NF_CT_NETLINK) |
| .nlattr_size = DCCP_NLATTR_SIZE, |
| .to_nlattr = dccp_to_nlattr, |
| .from_nlattr = nlattr_to_dccp, |
| .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr, |
| .nlattr_tuple_size = nf_ct_port_nlattr_tuple_size, |
| .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple, |
| .nla_policy = nf_ct_port_nla_policy, |
| #endif |
| #ifdef CONFIG_NF_CONNTRACK_TIMEOUT |
| .ctnl_timeout = { |
| .nlattr_to_obj = dccp_timeout_nlattr_to_obj, |
| .obj_to_nlattr = dccp_timeout_obj_to_nlattr, |
| .nlattr_max = CTA_TIMEOUT_DCCP_MAX, |
| .obj_size = sizeof(unsigned int) * CT_DCCP_MAX, |
| .nla_policy = dccp_timeout_nla_policy, |
| }, |
| #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */ |
| }; |