| /* (C) 1999-2001 Paul `Rusty' Russell |
| * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| */ |
| |
| #include <linux/types.h> |
| #include <linux/timer.h> |
| #include <linux/module.h> |
| #include <linux/in.h> |
| #include <linux/tcp.h> |
| #include <linux/spinlock.h> |
| #include <linux/skbuff.h> |
| #include <linux/ipv6.h> |
| #include <net/ip6_checksum.h> |
| #include <asm/unaligned.h> |
| |
| #include <net/tcp.h> |
| |
| #include <linux/netfilter.h> |
| #include <linux/netfilter_ipv4.h> |
| #include <linux/netfilter_ipv6.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_log.h> |
| #include <net/netfilter/ipv4/nf_conntrack_ipv4.h> |
| #include <net/netfilter/ipv6/nf_conntrack_ipv6.h> |
| |
| /* Do not check the TCP window for incoming packets */ |
| static int nf_ct_tcp_no_window_check __read_mostly = 1; |
| |
| /* "Be conservative in what you do, |
| be liberal in what you accept from others." |
| If it's non-zero, we mark only out of window RST segments as INVALID. */ |
| static int nf_ct_tcp_be_liberal __read_mostly = 0; |
| |
| /* If it is set to zero, we disable picking up already established |
| connections. */ |
| static int nf_ct_tcp_loose __read_mostly = 1; |
| |
| /* Max number of the retransmitted packets without receiving an (acceptable) |
| ACK from the destination. If this number is reached, a shorter timer |
| will be started. */ |
| static int nf_ct_tcp_max_retrans __read_mostly = 3; |
| |
| /* FIXME: Examine ipfilter's timeouts and conntrack transitions more |
| closely. They're more complex. --RR */ |
| |
| static const char *const tcp_conntrack_names[] = { |
| "NONE", |
| "SYN_SENT", |
| "SYN_RECV", |
| "ESTABLISHED", |
| "FIN_WAIT", |
| "CLOSE_WAIT", |
| "LAST_ACK", |
| "TIME_WAIT", |
| "CLOSE", |
| "SYN_SENT2", |
| }; |
| |
| #define SECS * HZ |
| #define MINS * 60 SECS |
| #define HOURS * 60 MINS |
| #define DAYS * 24 HOURS |
| |
| /* RFC1122 says the R2 limit should be at least 100 seconds. |
| Linux uses 15 packets as limit, which corresponds |
| to ~13-30min depending on RTO. */ |
| static unsigned int nf_ct_tcp_timeout_max_retrans __read_mostly = 5 MINS; |
| static unsigned int nf_ct_tcp_timeout_unacknowledged __read_mostly = 5 MINS; |
| |
| static unsigned int tcp_timeouts[TCP_CONNTRACK_MAX] __read_mostly = { |
| [TCP_CONNTRACK_SYN_SENT] = 2 MINS, |
| [TCP_CONNTRACK_SYN_RECV] = 60 SECS, |
| [TCP_CONNTRACK_ESTABLISHED] = 5 DAYS, |
| [TCP_CONNTRACK_FIN_WAIT] = 2 MINS, |
| [TCP_CONNTRACK_CLOSE_WAIT] = 60 SECS, |
| [TCP_CONNTRACK_LAST_ACK] = 30 SECS, |
| [TCP_CONNTRACK_TIME_WAIT] = 2 MINS, |
| [TCP_CONNTRACK_CLOSE] = 10 SECS, |
| [TCP_CONNTRACK_SYN_SENT2] = 2 MINS, |
| }; |
| |
| #define sNO TCP_CONNTRACK_NONE |
| #define sSS TCP_CONNTRACK_SYN_SENT |
| #define sSR TCP_CONNTRACK_SYN_RECV |
| #define sES TCP_CONNTRACK_ESTABLISHED |
| #define sFW TCP_CONNTRACK_FIN_WAIT |
| #define sCW TCP_CONNTRACK_CLOSE_WAIT |
| #define sLA TCP_CONNTRACK_LAST_ACK |
| #define sTW TCP_CONNTRACK_TIME_WAIT |
| #define sCL TCP_CONNTRACK_CLOSE |
| #define sS2 TCP_CONNTRACK_SYN_SENT2 |
| #define sIV TCP_CONNTRACK_MAX |
| #define sIG TCP_CONNTRACK_IGNORE |
| |
| /* What TCP flags are set from RST/SYN/FIN/ACK. */ |
| enum tcp_bit_set { |
| TCP_SYN_SET, |
| TCP_SYNACK_SET, |
| TCP_FIN_SET, |
| TCP_ACK_SET, |
| TCP_RST_SET, |
| TCP_NONE_SET, |
| }; |
| |
| /* |
| * The TCP state transition table needs a few words... |
| * |
| * 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 destinations can't receive segments |
| * we haven't seen. |
| * |
| * The checked segment is in window, but our windows are *not* |
| * equivalent with the ones of the sender/receiver. We always |
| * try to guess the state of the current sender. |
| * |
| * The meaning of the states are: |
| * |
| * NONE: initial state |
| * SYN_SENT: SYN-only packet seen |
| * SYN_SENT2: SYN-only packet seen from reply dir, simultaneous open |
| * SYN_RECV: SYN-ACK packet seen |
| * ESTABLISHED: ACK packet seen |
| * FIN_WAIT: FIN packet seen |
| * CLOSE_WAIT: ACK seen (after FIN) |
| * LAST_ACK: FIN seen (after FIN) |
| * TIME_WAIT: last ACK seen |
| * CLOSE: closed connection (RST) |
| * |
| * Packets marked as IGNORED (sIG): |
| * if they may be either invalid or valid |
| * and the receiver may send back a connection |
| * closing RST or a SYN/ACK. |
| * |
| * Packets marked as INVALID (sIV): |
| * if we regard them as truly invalid packets |
| */ |
| static const u8 tcp_conntracks[2][6][TCP_CONNTRACK_MAX] = { |
| { |
| /* ORIGINAL */ |
| /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ |
| /*syn*/ { sSS, sSS, sIG, sIG, sIG, sIG, sIG, sSS, sSS, sS2 }, |
| /* |
| * sNO -> sSS Initialize a new connection |
| * sSS -> sSS Retransmitted SYN |
| * sS2 -> sS2 Late retransmitted SYN |
| * sSR -> sIG |
| * sES -> sIG Error: SYNs in window outside the SYN_SENT state |
| * are errors. Receiver will reply with RST |
| * and close the connection. |
| * Or we are not in sync and hold a dead connection. |
| * sFW -> sIG |
| * sCW -> sIG |
| * sLA -> sIG |
| * sTW -> sSS Reopened connection (RFC 1122). |
| * sCL -> sSS |
| */ |
| /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ |
| /*synack*/ { sIV, sIV, sIG, sIG, sIG, sIG, sIG, sIG, sIG, sSR }, |
| /* |
| * sNO -> sIV Too late and no reason to do anything |
| * sSS -> sIV Client can't send SYN and then SYN/ACK |
| * sS2 -> sSR SYN/ACK sent to SYN2 in simultaneous open |
| * sSR -> sIG |
| * sES -> sIG Error: SYNs in window outside the SYN_SENT state |
| * are errors. Receiver will reply with RST |
| * and close the connection. |
| * Or we are not in sync and hold a dead connection. |
| * sFW -> sIG |
| * sCW -> sIG |
| * sLA -> sIG |
| * sTW -> sIG |
| * sCL -> sIG |
| */ |
| /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ |
| /*fin*/ { sIV, sIV, sFW, sFW, sLA, sLA, sLA, sTW, sCL, sIV }, |
| /* |
| * sNO -> sIV Too late and no reason to do anything... |
| * sSS -> sIV Client migth not send FIN in this state: |
| * we enforce waiting for a SYN/ACK reply first. |
| * sS2 -> sIV |
| * sSR -> sFW Close started. |
| * sES -> sFW |
| * sFW -> sLA FIN seen in both directions, waiting for |
| * the last ACK. |
| * Migth be a retransmitted FIN as well... |
| * sCW -> sLA |
| * sLA -> sLA Retransmitted FIN. Remain in the same state. |
| * sTW -> sTW |
| * sCL -> sCL |
| */ |
| /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ |
| /*ack*/ { sES, sIV, sES, sES, sCW, sCW, sTW, sTW, sCL, sIV }, |
| /* |
| * sNO -> sES Assumed. |
| * sSS -> sIV ACK is invalid: we haven't seen a SYN/ACK yet. |
| * sS2 -> sIV |
| * sSR -> sES Established state is reached. |
| * sES -> sES :-) |
| * sFW -> sCW Normal close request answered by ACK. |
| * sCW -> sCW |
| * sLA -> sTW Last ACK detected. |
| * sTW -> sTW Retransmitted last ACK. Remain in the same state. |
| * sCL -> sCL |
| */ |
| /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ |
| /*rst*/ { sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL }, |
| /*none*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV } |
| }, |
| { |
| /* REPLY */ |
| /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ |
| /*syn*/ { sIV, sS2, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sS2 }, |
| /* |
| * sNO -> sIV Never reached. |
| * sSS -> sS2 Simultaneous open |
| * sS2 -> sS2 Retransmitted simultaneous SYN |
| * sSR -> sIV Invalid SYN packets sent by the server |
| * sES -> sIV |
| * sFW -> sIV |
| * sCW -> sIV |
| * sLA -> sIV |
| * sTW -> sIV Reopened connection, but server may not do it. |
| * sCL -> sIV |
| */ |
| /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ |
| /*synack*/ { sIV, sSR, sIG, sIG, sIG, sIG, sIG, sIG, sIG, sSR }, |
| /* |
| * sSS -> sSR Standard open. |
| * sS2 -> sSR Simultaneous open |
| * sSR -> sIG Retransmitted SYN/ACK, ignore it. |
| * sES -> sIG Late retransmitted SYN/ACK? |
| * sFW -> sIG Might be SYN/ACK answering ignored SYN |
| * sCW -> sIG |
| * sLA -> sIG |
| * sTW -> sIG |
| * sCL -> sIG |
| */ |
| /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ |
| /*fin*/ { sIV, sIV, sFW, sFW, sLA, sLA, sLA, sTW, sCL, sIV }, |
| /* |
| * sSS -> sIV Server might not send FIN in this state. |
| * sS2 -> sIV |
| * sSR -> sFW Close started. |
| * sES -> sFW |
| * sFW -> sLA FIN seen in both directions. |
| * sCW -> sLA |
| * sLA -> sLA Retransmitted FIN. |
| * sTW -> sTW |
| * sCL -> sCL |
| */ |
| /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ |
| /*ack*/ { sIV, sIG, sSR, sES, sCW, sCW, sTW, sTW, sCL, sIG }, |
| /* |
| * sSS -> sIG Might be a half-open connection. |
| * sS2 -> sIG |
| * sSR -> sSR Might answer late resent SYN. |
| * sES -> sES :-) |
| * sFW -> sCW Normal close request answered by ACK. |
| * sCW -> sCW |
| * sLA -> sTW Last ACK detected. |
| * sTW -> sTW Retransmitted last ACK. |
| * sCL -> sCL |
| */ |
| /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ |
| /*rst*/ { sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL }, |
| /*none*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV } |
| } |
| }; |
| |
| static bool tcp_pkt_to_tuple(const struct sk_buff *skb, unsigned int dataoff, |
| struct nf_conntrack_tuple *tuple) |
| { |
| const struct tcphdr *hp; |
| struct tcphdr _hdr; |
| |
| /* Actually only need first 8 bytes. */ |
| hp = skb_header_pointer(skb, dataoff, 8, &_hdr); |
| if (hp == NULL) |
| return false; |
| |
| tuple->src.u.tcp.port = hp->source; |
| tuple->dst.u.tcp.port = hp->dest; |
| |
| return true; |
| } |
| |
| static bool tcp_invert_tuple(struct nf_conntrack_tuple *tuple, |
| const struct nf_conntrack_tuple *orig) |
| { |
| tuple->src.u.tcp.port = orig->dst.u.tcp.port; |
| tuple->dst.u.tcp.port = orig->src.u.tcp.port; |
| return true; |
| } |
| |
| /* Print out the per-protocol part of the tuple. */ |
| static int tcp_print_tuple(struct seq_file *s, |
| const struct nf_conntrack_tuple *tuple) |
| { |
| return seq_printf(s, "sport=%hu dport=%hu ", |
| ntohs(tuple->src.u.tcp.port), |
| ntohs(tuple->dst.u.tcp.port)); |
| } |
| |
| /* Print out the private part of the conntrack. */ |
| static int tcp_print_conntrack(struct seq_file *s, struct nf_conn *ct) |
| { |
| enum tcp_conntrack state; |
| |
| spin_lock_bh(&ct->lock); |
| state = ct->proto.tcp.state; |
| spin_unlock_bh(&ct->lock); |
| |
| return seq_printf(s, "%s ", tcp_conntrack_names[state]); |
| } |
| |
| static unsigned int get_conntrack_index(const struct tcphdr *tcph) |
| { |
| if (tcph->rst) return TCP_RST_SET; |
| else if (tcph->syn) return (tcph->ack ? TCP_SYNACK_SET : TCP_SYN_SET); |
| else if (tcph->fin) return TCP_FIN_SET; |
| else if (tcph->ack) return TCP_ACK_SET; |
| else return TCP_NONE_SET; |
| } |
| |
| /* TCP connection tracking based on 'Real Stateful TCP Packet Filtering |
| in IP Filter' by Guido van Rooij. |
| |
| http://www.sane.nl/events/sane2000/papers.html |
| http://www.darkart.com/mirrors/www.obfuscation.org/ipf/ |
| |
| The boundaries and the conditions are changed according to RFC793: |
| the packet must intersect the window (i.e. segments may be |
| after the right or before the left edge) and thus receivers may ACK |
| segments after the right edge of the window. |
| |
| td_maxend = max(sack + max(win,1)) seen in reply packets |
| td_maxwin = max(max(win, 1)) + (sack - ack) seen in sent packets |
| td_maxwin += seq + len - sender.td_maxend |
| if seq + len > sender.td_maxend |
| td_end = max(seq + len) seen in sent packets |
| |
| I. Upper bound for valid data: seq <= sender.td_maxend |
| II. Lower bound for valid data: seq + len >= sender.td_end - receiver.td_maxwin |
| III. Upper bound for valid (s)ack: sack <= receiver.td_end |
| IV. Lower bound for valid (s)ack: sack >= receiver.td_end - MAXACKWINDOW |
| |
| where sack is the highest right edge of sack block found in the packet |
| or ack in the case of packet without SACK option. |
| |
| The upper bound limit for a valid (s)ack is not ignored - |
| we doesn't have to deal with fragments. |
| */ |
| |
| static inline __u32 segment_seq_plus_len(__u32 seq, |
| size_t len, |
| unsigned int dataoff, |
| const struct tcphdr *tcph) |
| { |
| /* XXX Should I use payload length field in IP/IPv6 header ? |
| * - YK */ |
| return (seq + len - dataoff - tcph->doff*4 |
| + (tcph->syn ? 1 : 0) + (tcph->fin ? 1 : 0)); |
| } |
| |
| /* Fixme: what about big packets? */ |
| #define MAXACKWINCONST 66000 |
| #define MAXACKWINDOW(sender) \ |
| ((sender)->td_maxwin > MAXACKWINCONST ? (sender)->td_maxwin \ |
| : MAXACKWINCONST) |
| |
| /* |
| * Simplified tcp_parse_options routine from tcp_input.c |
| */ |
| static void tcp_options(const struct sk_buff *skb, |
| unsigned int dataoff, |
| const struct tcphdr *tcph, |
| struct ip_ct_tcp_state *state) |
| { |
| unsigned char buff[(15 * 4) - sizeof(struct tcphdr)]; |
| const unsigned char *ptr; |
| int length = (tcph->doff*4) - sizeof(struct tcphdr); |
| |
| if (!length) |
| return; |
| |
| ptr = skb_header_pointer(skb, dataoff + sizeof(struct tcphdr), |
| length, buff); |
| BUG_ON(ptr == NULL); |
| |
| state->td_scale = |
| state->flags = 0; |
| |
| while (length > 0) { |
| int opcode=*ptr++; |
| int opsize; |
| |
| switch (opcode) { |
| case TCPOPT_EOL: |
| return; |
| case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */ |
| length--; |
| continue; |
| default: |
| opsize=*ptr++; |
| if (opsize < 2) /* "silly options" */ |
| return; |
| if (opsize > length) |
| return; /* don't parse partial options */ |
| |
| if (opcode == TCPOPT_SACK_PERM |
| && opsize == TCPOLEN_SACK_PERM) |
| state->flags |= IP_CT_TCP_FLAG_SACK_PERM; |
| else if (opcode == TCPOPT_WINDOW |
| && opsize == TCPOLEN_WINDOW) { |
| state->td_scale = *(u_int8_t *)ptr; |
| |
| if (state->td_scale > 14) { |
| /* See RFC1323 */ |
| state->td_scale = 14; |
| } |
| state->flags |= |
| IP_CT_TCP_FLAG_WINDOW_SCALE; |
| } |
| ptr += opsize - 2; |
| length -= opsize; |
| } |
| } |
| } |
| |
| static void tcp_sack(const struct sk_buff *skb, unsigned int dataoff, |
| const struct tcphdr *tcph, __u32 *sack) |
| { |
| unsigned char buff[(15 * 4) - sizeof(struct tcphdr)]; |
| const unsigned char *ptr; |
| int length = (tcph->doff*4) - sizeof(struct tcphdr); |
| __u32 tmp; |
| |
| if (!length) |
| return; |
| |
| ptr = skb_header_pointer(skb, dataoff + sizeof(struct tcphdr), |
| length, buff); |
| BUG_ON(ptr == NULL); |
| |
| /* Fast path for timestamp-only option */ |
| if (length == TCPOLEN_TSTAMP_ALIGNED |
| && *(__be32 *)ptr == htonl((TCPOPT_NOP << 24) |
| | (TCPOPT_NOP << 16) |
| | (TCPOPT_TIMESTAMP << 8) |
| | TCPOLEN_TIMESTAMP)) |
| return; |
| |
| while (length > 0) { |
| int opcode = *ptr++; |
| int opsize, i; |
| |
| switch (opcode) { |
| case TCPOPT_EOL: |
| return; |
| case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */ |
| length--; |
| continue; |
| default: |
| opsize = *ptr++; |
| if (opsize < 2) /* "silly options" */ |
| return; |
| if (opsize > length) |
| return; /* don't parse partial options */ |
| |
| if (opcode == TCPOPT_SACK |
| && opsize >= (TCPOLEN_SACK_BASE |
| + TCPOLEN_SACK_PERBLOCK) |
| && !((opsize - TCPOLEN_SACK_BASE) |
| % TCPOLEN_SACK_PERBLOCK)) { |
| for (i = 0; |
| i < (opsize - TCPOLEN_SACK_BASE); |
| i += TCPOLEN_SACK_PERBLOCK) { |
| tmp = get_unaligned_be32((__be32 *)(ptr+i)+1); |
| |
| if (after(tmp, *sack)) |
| *sack = tmp; |
| } |
| return; |
| } |
| ptr += opsize - 2; |
| length -= opsize; |
| } |
| } |
| } |
| |
| #ifdef CONFIG_NF_NAT_NEEDED |
| static inline s16 nat_offset(const struct nf_conn *ct, |
| enum ip_conntrack_dir dir, |
| u32 seq) |
| { |
| typeof(nf_ct_nat_offset) get_offset = rcu_dereference(nf_ct_nat_offset); |
| |
| return get_offset != NULL ? get_offset(ct, dir, seq) : 0; |
| } |
| #define NAT_OFFSET(pf, ct, dir, seq) \ |
| (pf == NFPROTO_IPV4 ? nat_offset(ct, dir, seq) : 0) |
| #else |
| #define NAT_OFFSET(pf, ct, dir, seq) 0 |
| #endif |
| |
| static bool tcp_in_window(const struct nf_conn *ct, |
| struct ip_ct_tcp *state, |
| enum ip_conntrack_dir dir, |
| unsigned int index, |
| const struct sk_buff *skb, |
| unsigned int dataoff, |
| const struct tcphdr *tcph, |
| u_int8_t pf) |
| { |
| struct net *net = nf_ct_net(ct); |
| struct ip_ct_tcp_state *sender = &state->seen[dir]; |
| struct ip_ct_tcp_state *receiver = &state->seen[!dir]; |
| const struct nf_conntrack_tuple *tuple = &ct->tuplehash[dir].tuple; |
| __u32 seq, ack, sack, end, win, swin; |
| s16 receiver_offset; |
| bool res; |
| |
| if (nf_ct_tcp_no_window_check) |
| return true; |
| |
| /* |
| * Get the required data from the packet. |
| */ |
| seq = ntohl(tcph->seq); |
| ack = sack = ntohl(tcph->ack_seq); |
| win = ntohs(tcph->window); |
| end = segment_seq_plus_len(seq, skb->len, dataoff, tcph); |
| |
| if (receiver->flags & IP_CT_TCP_FLAG_SACK_PERM) |
| tcp_sack(skb, dataoff, tcph, &sack); |
| |
| /* Take into account NAT sequence number mangling */ |
| receiver_offset = NAT_OFFSET(pf, ct, !dir, ack - 1); |
| ack -= receiver_offset; |
| sack -= receiver_offset; |
| |
| pr_debug("tcp_in_window: START\n"); |
| pr_debug("tcp_in_window: "); |
| nf_ct_dump_tuple(tuple); |
| pr_debug("seq=%u ack=%u+(%d) sack=%u+(%d) win=%u end=%u\n", |
| seq, ack, receiver_offset, sack, receiver_offset, win, end); |
| pr_debug("tcp_in_window: sender end=%u maxend=%u maxwin=%u scale=%i " |
| "receiver end=%u maxend=%u maxwin=%u scale=%i\n", |
| sender->td_end, sender->td_maxend, sender->td_maxwin, |
| sender->td_scale, |
| receiver->td_end, receiver->td_maxend, receiver->td_maxwin, |
| receiver->td_scale); |
| |
| if (sender->td_maxwin == 0) { |
| /* |
| * Initialize sender data. |
| */ |
| if (tcph->syn) { |
| /* |
| * SYN-ACK in reply to a SYN |
| * or SYN from reply direction in simultaneous open. |
| */ |
| sender->td_end = |
| sender->td_maxend = end; |
| sender->td_maxwin = (win == 0 ? 1 : win); |
| |
| tcp_options(skb, dataoff, tcph, sender); |
| /* |
| * RFC 1323: |
| * Both sides must send the Window Scale option |
| * to enable window scaling in either direction. |
| */ |
| if (!(sender->flags & IP_CT_TCP_FLAG_WINDOW_SCALE |
| && receiver->flags & IP_CT_TCP_FLAG_WINDOW_SCALE)) |
| sender->td_scale = |
| receiver->td_scale = 0; |
| if (!tcph->ack) |
| /* Simultaneous open */ |
| return true; |
| } else { |
| /* |
| * We are in the middle of a connection, |
| * its history is lost for us. |
| * Let's try to use the data from the packet. |
| */ |
| sender->td_end = end; |
| win <<= sender->td_scale; |
| sender->td_maxwin = (win == 0 ? 1 : win); |
| sender->td_maxend = end + sender->td_maxwin; |
| /* |
| * We haven't seen traffic in the other direction yet |
| * but we have to tweak window tracking to pass III |
| * and IV until that happens. |
| */ |
| if (receiver->td_maxwin == 0) |
| receiver->td_end = receiver->td_maxend = sack; |
| } |
| } else if (((state->state == TCP_CONNTRACK_SYN_SENT |
| && dir == IP_CT_DIR_ORIGINAL) |
| || (state->state == TCP_CONNTRACK_SYN_RECV |
| && dir == IP_CT_DIR_REPLY)) |
| && after(end, sender->td_end)) { |
| /* |
| * RFC 793: "if a TCP is reinitialized ... then it need |
| * not wait at all; it must only be sure to use sequence |
| * numbers larger than those recently used." |
| */ |
| sender->td_end = |
| sender->td_maxend = end; |
| sender->td_maxwin = (win == 0 ? 1 : win); |
| |
| tcp_options(skb, dataoff, tcph, sender); |
| } |
| |
| if (!(tcph->ack)) { |
| /* |
| * If there is no ACK, just pretend it was set and OK. |
| */ |
| ack = sack = receiver->td_end; |
| } else if (((tcp_flag_word(tcph) & (TCP_FLAG_ACK|TCP_FLAG_RST)) == |
| (TCP_FLAG_ACK|TCP_FLAG_RST)) |
| && (ack == 0)) { |
| /* |
| * Broken TCP stacks, that set ACK in RST packets as well |
| * with zero ack value. |
| */ |
| ack = sack = receiver->td_end; |
| } |
| |
| if (seq == end |
| && (!tcph->rst |
| || (seq == 0 && state->state == TCP_CONNTRACK_SYN_SENT))) |
| /* |
| * Packets contains no data: we assume it is valid |
| * and check the ack value only. |
| * However RST segments are always validated by their |
| * SEQ number, except when seq == 0 (reset sent answering |
| * SYN. |
| */ |
| seq = end = sender->td_end; |
| |
| pr_debug("tcp_in_window: "); |
| nf_ct_dump_tuple(tuple); |
| pr_debug("seq=%u ack=%u+(%d) sack=%u+(%d) win=%u end=%u\n", |
| seq, ack, receiver_offset, sack, receiver_offset, win, end); |
| pr_debug("tcp_in_window: sender end=%u maxend=%u maxwin=%u scale=%i " |
| "receiver end=%u maxend=%u maxwin=%u scale=%i\n", |
| sender->td_end, sender->td_maxend, sender->td_maxwin, |
| sender->td_scale, |
| receiver->td_end, receiver->td_maxend, receiver->td_maxwin, |
| receiver->td_scale); |
| |
| pr_debug("tcp_in_window: I=%i II=%i III=%i IV=%i\n", |
| before(seq, sender->td_maxend + 1), |
| after(end, sender->td_end - receiver->td_maxwin - 1), |
| before(sack, receiver->td_end + 1), |
| after(sack, receiver->td_end - MAXACKWINDOW(sender) - 1)); |
| |
| if (before(seq, sender->td_maxend + 1) && |
| after(end, sender->td_end - receiver->td_maxwin - 1) && |
| before(sack, receiver->td_end + 1) && |
| after(sack, receiver->td_end - MAXACKWINDOW(sender) - 1)) { |
| /* |
| * Take into account window scaling (RFC 1323). |
| */ |
| if (!tcph->syn) |
| win <<= sender->td_scale; |
| |
| /* |
| * Update sender data. |
| */ |
| swin = win + (sack - ack); |
| if (sender->td_maxwin < swin) |
| sender->td_maxwin = swin; |
| if (after(end, sender->td_end)) { |
| sender->td_end = end; |
| sender->flags |= IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED; |
| } |
| if (tcph->ack) { |
| if (!(sender->flags & IP_CT_TCP_FLAG_MAXACK_SET)) { |
| sender->td_maxack = ack; |
| sender->flags |= IP_CT_TCP_FLAG_MAXACK_SET; |
| } else if (after(ack, sender->td_maxack)) |
| sender->td_maxack = ack; |
| } |
| |
| /* |
| * Update receiver data. |
| */ |
| if (receiver->td_maxwin != 0 && after(end, sender->td_maxend)) |
| receiver->td_maxwin += end - sender->td_maxend; |
| if (after(sack + win, receiver->td_maxend - 1)) { |
| receiver->td_maxend = sack + win; |
| if (win == 0) |
| receiver->td_maxend++; |
| } |
| if (ack == receiver->td_end) |
| receiver->flags &= ~IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED; |
| |
| /* |
| * Check retransmissions. |
| */ |
| if (index == TCP_ACK_SET) { |
| if (state->last_dir == dir |
| && state->last_seq == seq |
| && state->last_ack == ack |
| && state->last_end == end |
| && state->last_win == win) |
| state->retrans++; |
| else { |
| state->last_dir = dir; |
| state->last_seq = seq; |
| state->last_ack = ack; |
| state->last_end = end; |
| state->last_win = win; |
| state->retrans = 0; |
| } |
| } |
| res = true; |
| } else { |
| res = false; |
| if (sender->flags & IP_CT_TCP_FLAG_BE_LIBERAL || |
| nf_ct_tcp_be_liberal) |
| res = true; |
| if (!res && LOG_INVALID(net, IPPROTO_TCP)) |
| nf_log_packet(pf, 0, skb, NULL, NULL, NULL, |
| "nf_ct_tcp: %s ", |
| before(seq, sender->td_maxend + 1) ? |
| after(end, sender->td_end - receiver->td_maxwin - 1) ? |
| before(sack, receiver->td_end + 1) ? |
| after(sack, receiver->td_end - MAXACKWINDOW(sender) - 1) ? "BUG" |
| : "ACK is under the lower bound (possible overly delayed ACK)" |
| : "ACK is over the upper bound (ACKed data not seen yet)" |
| : "SEQ is under the lower bound (already ACKed data retransmitted)" |
| : "SEQ is over the upper bound (over the window of the receiver)"); |
| } |
| |
| pr_debug("tcp_in_window: res=%u sender end=%u maxend=%u maxwin=%u " |
| "receiver end=%u maxend=%u maxwin=%u\n", |
| res, sender->td_end, sender->td_maxend, sender->td_maxwin, |
| receiver->td_end, receiver->td_maxend, receiver->td_maxwin); |
| |
| return res; |
| } |
| |
| /* table of valid flag combinations - PUSH, ECE and CWR are always valid */ |
| static const u8 tcp_valid_flags[(TCPHDR_FIN|TCPHDR_SYN|TCPHDR_RST|TCPHDR_ACK| |
| TCPHDR_URG) + 1] = |
| { |
| [TCPHDR_SYN] = 1, |
| [TCPHDR_SYN|TCPHDR_URG] = 1, |
| [TCPHDR_SYN|TCPHDR_ACK] = 1, |
| [TCPHDR_RST] = 1, |
| [TCPHDR_RST|TCPHDR_ACK] = 1, |
| [TCPHDR_FIN|TCPHDR_ACK] = 1, |
| [TCPHDR_FIN|TCPHDR_ACK|TCPHDR_URG] = 1, |
| [TCPHDR_ACK] = 1, |
| [TCPHDR_ACK|TCPHDR_URG] = 1, |
| }; |
| |
| /* Protect conntrack agaist broken packets. Code taken from ipt_unclean.c. */ |
| static int tcp_error(struct net *net, struct nf_conn *tmpl, |
| struct sk_buff *skb, |
| unsigned int dataoff, |
| enum ip_conntrack_info *ctinfo, |
| u_int8_t pf, |
| unsigned int hooknum) |
| { |
| const struct tcphdr *th; |
| struct tcphdr _tcph; |
| unsigned int tcplen = skb->len - dataoff; |
| u_int8_t tcpflags; |
| |
| /* Smaller that minimal TCP header? */ |
| th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph); |
| if (th == NULL) { |
| if (LOG_INVALID(net, IPPROTO_TCP)) |
| nf_log_packet(pf, 0, skb, NULL, NULL, NULL, |
| "nf_ct_tcp: short packet "); |
| return -NF_ACCEPT; |
| } |
| |
| /* Not whole TCP header or malformed packet */ |
| if (th->doff*4 < sizeof(struct tcphdr) || tcplen < th->doff*4) { |
| if (LOG_INVALID(net, IPPROTO_TCP)) |
| nf_log_packet(pf, 0, skb, NULL, NULL, NULL, |
| "nf_ct_tcp: truncated/malformed packet "); |
| return -NF_ACCEPT; |
| } |
| |
| /* Checksum invalid? Ignore. |
| * We skip checking packets on the outgoing path |
| * because the checksum is assumed to be correct. |
| */ |
| /* FIXME: Source route IP option packets --RR */ |
| if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING && |
| nf_checksum(skb, hooknum, dataoff, IPPROTO_TCP, pf)) { |
| if (LOG_INVALID(net, IPPROTO_TCP)) |
| nf_log_packet(pf, 0, skb, NULL, NULL, NULL, |
| "nf_ct_tcp: bad TCP checksum "); |
| return -NF_ACCEPT; |
| } |
| |
| /* Check TCP flags. */ |
| tcpflags = (tcp_flag_byte(th) & ~(TCPHDR_ECE|TCPHDR_CWR|TCPHDR_PSH)); |
| if (!tcp_valid_flags[tcpflags]) { |
| if (LOG_INVALID(net, IPPROTO_TCP)) |
| nf_log_packet(pf, 0, skb, NULL, NULL, NULL, |
| "nf_ct_tcp: invalid TCP flag combination "); |
| return -NF_ACCEPT; |
| } |
| |
| return NF_ACCEPT; |
| } |
| |
| /* Returns verdict for packet, or -1 for invalid. */ |
| static int tcp_packet(struct nf_conn *ct, |
| const struct sk_buff *skb, |
| unsigned int dataoff, |
| enum ip_conntrack_info ctinfo, |
| u_int8_t pf, |
| unsigned int hooknum) |
| { |
| struct net *net = nf_ct_net(ct); |
| struct nf_conntrack_tuple *tuple; |
| enum tcp_conntrack new_state, old_state; |
| enum ip_conntrack_dir dir; |
| const struct tcphdr *th; |
| struct tcphdr _tcph; |
| unsigned long timeout; |
| unsigned int index; |
| |
| th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph); |
| BUG_ON(th == NULL); |
| |
| spin_lock_bh(&ct->lock); |
| old_state = ct->proto.tcp.state; |
| dir = CTINFO2DIR(ctinfo); |
| index = get_conntrack_index(th); |
| new_state = tcp_conntracks[dir][index][old_state]; |
| tuple = &ct->tuplehash[dir].tuple; |
| |
| switch (new_state) { |
| case TCP_CONNTRACK_SYN_SENT: |
| if (old_state < TCP_CONNTRACK_TIME_WAIT) |
| break; |
| /* RFC 1122: "When a connection is closed actively, |
| * it MUST linger in TIME-WAIT state for a time 2xMSL |
| * (Maximum Segment Lifetime). However, it MAY accept |
| * a new SYN from the remote TCP to reopen the connection |
| * directly from TIME-WAIT state, if..." |
| * We ignore the conditions because we are in the |
| * TIME-WAIT state anyway. |
| * |
| * Handle aborted connections: we and the server |
| * think there is an existing connection but the client |
| * aborts it and starts a new one. |
| */ |
| if (((ct->proto.tcp.seen[dir].flags |
| | ct->proto.tcp.seen[!dir].flags) |
| & IP_CT_TCP_FLAG_CLOSE_INIT) |
| || (ct->proto.tcp.last_dir == dir |
| && ct->proto.tcp.last_index == TCP_RST_SET)) { |
| /* Attempt to reopen a closed/aborted connection. |
| * Delete this connection and look up again. */ |
| spin_unlock_bh(&ct->lock); |
| |
| /* Only repeat if we can actually remove the timer. |
| * Destruction may already be in progress in process |
| * context and we must give it a chance to terminate. |
| */ |
| if (nf_ct_kill(ct)) |
| return -NF_REPEAT; |
| return NF_DROP; |
| } |
| /* Fall through */ |
| case TCP_CONNTRACK_IGNORE: |
| /* Ignored packets: |
| * |
| * Our connection entry may be out of sync, so ignore |
| * packets which may signal the real connection between |
| * the client and the server. |
| * |
| * a) SYN in ORIGINAL |
| * b) SYN/ACK in REPLY |
| * c) ACK in reply direction after initial SYN in original. |
| * |
| * If the ignored packet is invalid, the receiver will send |
| * a RST we'll catch below. |
| */ |
| if (index == TCP_SYNACK_SET |
| && ct->proto.tcp.last_index == TCP_SYN_SET |
| && ct->proto.tcp.last_dir != dir |
| && ntohl(th->ack_seq) == ct->proto.tcp.last_end) { |
| /* b) This SYN/ACK acknowledges a SYN that we earlier |
| * ignored as invalid. This means that the client and |
| * the server are both in sync, while the firewall is |
| * not. We get in sync from the previously annotated |
| * values. |
| */ |
| old_state = TCP_CONNTRACK_SYN_SENT; |
| new_state = TCP_CONNTRACK_SYN_RECV; |
| ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_end = |
| ct->proto.tcp.last_end; |
| ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_maxend = |
| ct->proto.tcp.last_end; |
| ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_maxwin = |
| ct->proto.tcp.last_win == 0 ? |
| 1 : ct->proto.tcp.last_win; |
| ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_scale = |
| ct->proto.tcp.last_wscale; |
| ct->proto.tcp.seen[ct->proto.tcp.last_dir].flags = |
| ct->proto.tcp.last_flags; |
| memset(&ct->proto.tcp.seen[dir], 0, |
| sizeof(struct ip_ct_tcp_state)); |
| break; |
| } |
| ct->proto.tcp.last_index = index; |
| ct->proto.tcp.last_dir = dir; |
| ct->proto.tcp.last_seq = ntohl(th->seq); |
| ct->proto.tcp.last_end = |
| segment_seq_plus_len(ntohl(th->seq), skb->len, dataoff, th); |
| ct->proto.tcp.last_win = ntohs(th->window); |
| |
| /* a) This is a SYN in ORIGINAL. The client and the server |
| * may be in sync but we are not. In that case, we annotate |
| * the TCP options and let the packet go through. If it is a |
| * valid SYN packet, the server will reply with a SYN/ACK, and |
| * then we'll get in sync. Otherwise, the server ignores it. */ |
| if (index == TCP_SYN_SET && dir == IP_CT_DIR_ORIGINAL) { |
| struct ip_ct_tcp_state seen = {}; |
| |
| ct->proto.tcp.last_flags = |
| ct->proto.tcp.last_wscale = 0; |
| tcp_options(skb, dataoff, th, &seen); |
| if (seen.flags & IP_CT_TCP_FLAG_WINDOW_SCALE) { |
| ct->proto.tcp.last_flags |= |
| IP_CT_TCP_FLAG_WINDOW_SCALE; |
| ct->proto.tcp.last_wscale = seen.td_scale; |
| } |
| if (seen.flags & IP_CT_TCP_FLAG_SACK_PERM) { |
| ct->proto.tcp.last_flags |= |
| IP_CT_TCP_FLAG_SACK_PERM; |
| } |
| } |
| spin_unlock_bh(&ct->lock); |
| if (LOG_INVALID(net, IPPROTO_TCP)) |
| nf_log_packet(pf, 0, skb, NULL, NULL, NULL, |
| "nf_ct_tcp: invalid packet ignored "); |
| return NF_ACCEPT; |
| case TCP_CONNTRACK_MAX: |
| /* Invalid packet */ |
| pr_debug("nf_ct_tcp: Invalid dir=%i index=%u ostate=%u\n", |
| dir, get_conntrack_index(th), old_state); |
| spin_unlock_bh(&ct->lock); |
| if (LOG_INVALID(net, IPPROTO_TCP)) |
| nf_log_packet(pf, 0, skb, NULL, NULL, NULL, |
| "nf_ct_tcp: invalid state "); |
| return -NF_ACCEPT; |
| case TCP_CONNTRACK_CLOSE: |
| if (index == TCP_RST_SET |
| && (ct->proto.tcp.seen[!dir].flags & IP_CT_TCP_FLAG_MAXACK_SET) |
| && before(ntohl(th->seq), ct->proto.tcp.seen[!dir].td_maxack)) { |
| /* Invalid RST */ |
| spin_unlock_bh(&ct->lock); |
| if (LOG_INVALID(net, IPPROTO_TCP)) |
| nf_log_packet(pf, 0, skb, NULL, NULL, NULL, |
| "nf_ct_tcp: invalid RST "); |
| return -NF_ACCEPT; |
| } |
| if (index == TCP_RST_SET |
| && ((test_bit(IPS_SEEN_REPLY_BIT, &ct->status) |
| && ct->proto.tcp.last_index == TCP_SYN_SET) |
| || (!test_bit(IPS_ASSURED_BIT, &ct->status) |
| && ct->proto.tcp.last_index == TCP_ACK_SET)) |
| && ntohl(th->ack_seq) == ct->proto.tcp.last_end) { |
| /* RST sent to invalid SYN or ACK we had let through |
| * at a) and c) above: |
| * |
| * a) SYN was in window then |
| * c) we hold a half-open connection. |
| * |
| * Delete our connection entry. |
| * We skip window checking, because packet might ACK |
| * segments we ignored. */ |
| goto in_window; |
| } |
| /* Just fall through */ |
| default: |
| /* Keep compilers happy. */ |
| break; |
| } |
| |
| if (!tcp_in_window(ct, &ct->proto.tcp, dir, index, |
| skb, dataoff, th, pf)) { |
| spin_unlock_bh(&ct->lock); |
| return -NF_ACCEPT; |
| } |
| in_window: |
| /* From now on we have got in-window packets */ |
| ct->proto.tcp.last_index = index; |
| ct->proto.tcp.last_dir = dir; |
| |
| pr_debug("tcp_conntracks: "); |
| nf_ct_dump_tuple(tuple); |
| pr_debug("syn=%i ack=%i fin=%i rst=%i old=%i new=%i\n", |
| (th->syn ? 1 : 0), (th->ack ? 1 : 0), |
| (th->fin ? 1 : 0), (th->rst ? 1 : 0), |
| old_state, new_state); |
| |
| ct->proto.tcp.state = new_state; |
| if (old_state != new_state |
| && new_state == TCP_CONNTRACK_FIN_WAIT) |
| ct->proto.tcp.seen[dir].flags |= IP_CT_TCP_FLAG_CLOSE_INIT; |
| |
| if (ct->proto.tcp.retrans >= nf_ct_tcp_max_retrans && |
| tcp_timeouts[new_state] > nf_ct_tcp_timeout_max_retrans) |
| timeout = nf_ct_tcp_timeout_max_retrans; |
| else if ((ct->proto.tcp.seen[0].flags | ct->proto.tcp.seen[1].flags) & |
| IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED && |
| tcp_timeouts[new_state] > nf_ct_tcp_timeout_unacknowledged) |
| timeout = nf_ct_tcp_timeout_unacknowledged; |
| else |
| timeout = tcp_timeouts[new_state]; |
| spin_unlock_bh(&ct->lock); |
| |
| if (new_state != old_state) |
| nf_conntrack_event_cache(IPCT_PROTOINFO, ct); |
| |
| if (!test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) { |
| /* If only reply is a RST, we can consider ourselves not to |
| have an established connection: this is a fairly common |
| problem case, so we can delete the conntrack |
| immediately. --RR */ |
| if (th->rst) { |
| nf_ct_kill_acct(ct, ctinfo, skb); |
| return NF_ACCEPT; |
| } |
| } else if (!test_bit(IPS_ASSURED_BIT, &ct->status) |
| && (old_state == TCP_CONNTRACK_SYN_RECV |
| || old_state == TCP_CONNTRACK_ESTABLISHED) |
| && new_state == TCP_CONNTRACK_ESTABLISHED) { |
| /* Set ASSURED if we see see valid ack in ESTABLISHED |
| after SYN_RECV or a valid answer for a picked up |
| connection. */ |
| set_bit(IPS_ASSURED_BIT, &ct->status); |
| nf_conntrack_event_cache(IPCT_ASSURED, ct); |
| } |
| nf_ct_refresh_acct(ct, ctinfo, skb, timeout); |
| |
| return NF_ACCEPT; |
| } |
| |
| /* Called when a new connection for this protocol found. */ |
| static bool tcp_new(struct nf_conn *ct, const struct sk_buff *skb, |
| unsigned int dataoff) |
| { |
| enum tcp_conntrack new_state; |
| const struct tcphdr *th; |
| struct tcphdr _tcph; |
| const struct ip_ct_tcp_state *sender = &ct->proto.tcp.seen[0]; |
| const struct ip_ct_tcp_state *receiver = &ct->proto.tcp.seen[1]; |
| |
| th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph); |
| BUG_ON(th == NULL); |
| |
| /* Don't need lock here: this conntrack not in circulation yet */ |
| new_state = tcp_conntracks[0][get_conntrack_index(th)][TCP_CONNTRACK_NONE]; |
| |
| /* Invalid: delete conntrack */ |
| if (new_state >= TCP_CONNTRACK_MAX) { |
| pr_debug("nf_ct_tcp: invalid new deleting.\n"); |
| return false; |
| } |
| |
| if (new_state == TCP_CONNTRACK_SYN_SENT) { |
| memset(&ct->proto.tcp, 0, sizeof(ct->proto.tcp)); |
| /* SYN packet */ |
| ct->proto.tcp.seen[0].td_end = |
| segment_seq_plus_len(ntohl(th->seq), skb->len, |
| dataoff, th); |
| ct->proto.tcp.seen[0].td_maxwin = ntohs(th->window); |
| if (ct->proto.tcp.seen[0].td_maxwin == 0) |
| ct->proto.tcp.seen[0].td_maxwin = 1; |
| ct->proto.tcp.seen[0].td_maxend = |
| ct->proto.tcp.seen[0].td_end; |
| |
| tcp_options(skb, dataoff, th, &ct->proto.tcp.seen[0]); |
| } else if (nf_ct_tcp_loose == 0) { |
| /* Don't try to pick up connections. */ |
| return false; |
| } else { |
| memset(&ct->proto.tcp, 0, sizeof(ct->proto.tcp)); |
| /* |
| * We are in the middle of a connection, |
| * its history is lost for us. |
| * Let's try to use the data from the packet. |
| */ |
| ct->proto.tcp.seen[0].td_end = |
| segment_seq_plus_len(ntohl(th->seq), skb->len, |
| dataoff, th); |
| ct->proto.tcp.seen[0].td_maxwin = ntohs(th->window); |
| if (ct->proto.tcp.seen[0].td_maxwin == 0) |
| ct->proto.tcp.seen[0].td_maxwin = 1; |
| ct->proto.tcp.seen[0].td_maxend = |
| ct->proto.tcp.seen[0].td_end + |
| ct->proto.tcp.seen[0].td_maxwin; |
| |
| /* We assume SACK and liberal window checking to handle |
| * window scaling */ |
| ct->proto.tcp.seen[0].flags = |
| ct->proto.tcp.seen[1].flags = IP_CT_TCP_FLAG_SACK_PERM | |
| IP_CT_TCP_FLAG_BE_LIBERAL; |
| } |
| |
| /* tcp_packet will set them */ |
| ct->proto.tcp.last_index = TCP_NONE_SET; |
| |
| pr_debug("tcp_new: sender end=%u maxend=%u maxwin=%u scale=%i " |
| "receiver end=%u maxend=%u maxwin=%u scale=%i\n", |
| sender->td_end, sender->td_maxend, sender->td_maxwin, |
| sender->td_scale, |
| receiver->td_end, receiver->td_maxend, receiver->td_maxwin, |
| receiver->td_scale); |
| return true; |
| } |
| |
| #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) |
| |
| #include <linux/netfilter/nfnetlink.h> |
| #include <linux/netfilter/nfnetlink_conntrack.h> |
| |
| static int tcp_to_nlattr(struct sk_buff *skb, struct nlattr *nla, |
| struct nf_conn *ct) |
| { |
| struct nlattr *nest_parms; |
| struct nf_ct_tcp_flags tmp = {}; |
| |
| spin_lock_bh(&ct->lock); |
| nest_parms = nla_nest_start(skb, CTA_PROTOINFO_TCP | NLA_F_NESTED); |
| if (!nest_parms) |
| goto nla_put_failure; |
| |
| NLA_PUT_U8(skb, CTA_PROTOINFO_TCP_STATE, ct->proto.tcp.state); |
| |
| NLA_PUT_U8(skb, CTA_PROTOINFO_TCP_WSCALE_ORIGINAL, |
| ct->proto.tcp.seen[0].td_scale); |
| |
| NLA_PUT_U8(skb, CTA_PROTOINFO_TCP_WSCALE_REPLY, |
| ct->proto.tcp.seen[1].td_scale); |
| |
| tmp.flags = ct->proto.tcp.seen[0].flags; |
| NLA_PUT(skb, CTA_PROTOINFO_TCP_FLAGS_ORIGINAL, |
| sizeof(struct nf_ct_tcp_flags), &tmp); |
| |
| tmp.flags = ct->proto.tcp.seen[1].flags; |
| NLA_PUT(skb, CTA_PROTOINFO_TCP_FLAGS_REPLY, |
| sizeof(struct nf_ct_tcp_flags), &tmp); |
| spin_unlock_bh(&ct->lock); |
| |
| nla_nest_end(skb, nest_parms); |
| |
| return 0; |
| |
| nla_put_failure: |
| spin_unlock_bh(&ct->lock); |
| return -1; |
| } |
| |
| static const struct nla_policy tcp_nla_policy[CTA_PROTOINFO_TCP_MAX+1] = { |
| [CTA_PROTOINFO_TCP_STATE] = { .type = NLA_U8 }, |
| [CTA_PROTOINFO_TCP_WSCALE_ORIGINAL] = { .type = NLA_U8 }, |
| [CTA_PROTOINFO_TCP_WSCALE_REPLY] = { .type = NLA_U8 }, |
| [CTA_PROTOINFO_TCP_FLAGS_ORIGINAL] = { .len = sizeof(struct nf_ct_tcp_flags) }, |
| [CTA_PROTOINFO_TCP_FLAGS_REPLY] = { .len = sizeof(struct nf_ct_tcp_flags) }, |
| }; |
| |
| static int nlattr_to_tcp(struct nlattr *cda[], struct nf_conn *ct) |
| { |
| struct nlattr *pattr = cda[CTA_PROTOINFO_TCP]; |
| struct nlattr *tb[CTA_PROTOINFO_TCP_MAX+1]; |
| int err; |
| |
| /* updates could not contain anything about the private |
| * protocol info, in that case skip the parsing */ |
| if (!pattr) |
| return 0; |
| |
| err = nla_parse_nested(tb, CTA_PROTOINFO_TCP_MAX, pattr, tcp_nla_policy); |
| if (err < 0) |
| return err; |
| |
| if (tb[CTA_PROTOINFO_TCP_STATE] && |
| nla_get_u8(tb[CTA_PROTOINFO_TCP_STATE]) >= TCP_CONNTRACK_MAX) |
| return -EINVAL; |
| |
| spin_lock_bh(&ct->lock); |
| if (tb[CTA_PROTOINFO_TCP_STATE]) |
| ct->proto.tcp.state = nla_get_u8(tb[CTA_PROTOINFO_TCP_STATE]); |
| |
| if (tb[CTA_PROTOINFO_TCP_FLAGS_ORIGINAL]) { |
| struct nf_ct_tcp_flags *attr = |
| nla_data(tb[CTA_PROTOINFO_TCP_FLAGS_ORIGINAL]); |
| ct->proto.tcp.seen[0].flags &= ~attr->mask; |
| ct->proto.tcp.seen[0].flags |= attr->flags & attr->mask; |
| } |
| |
| if (tb[CTA_PROTOINFO_TCP_FLAGS_REPLY]) { |
| struct nf_ct_tcp_flags *attr = |
| nla_data(tb[CTA_PROTOINFO_TCP_FLAGS_REPLY]); |
| ct->proto.tcp.seen[1].flags &= ~attr->mask; |
| ct->proto.tcp.seen[1].flags |= attr->flags & attr->mask; |
| } |
| |
| if (tb[CTA_PROTOINFO_TCP_WSCALE_ORIGINAL] && |
| tb[CTA_PROTOINFO_TCP_WSCALE_REPLY] && |
| ct->proto.tcp.seen[0].flags & IP_CT_TCP_FLAG_WINDOW_SCALE && |
| ct->proto.tcp.seen[1].flags & IP_CT_TCP_FLAG_WINDOW_SCALE) { |
| ct->proto.tcp.seen[0].td_scale = |
| nla_get_u8(tb[CTA_PROTOINFO_TCP_WSCALE_ORIGINAL]); |
| ct->proto.tcp.seen[1].td_scale = |
| nla_get_u8(tb[CTA_PROTOINFO_TCP_WSCALE_REPLY]); |
| } |
| spin_unlock_bh(&ct->lock); |
| |
| return 0; |
| } |
| |
| static int tcp_nlattr_size(void) |
| { |
| return nla_total_size(0) /* CTA_PROTOINFO_TCP */ |
| + nla_policy_len(tcp_nla_policy, CTA_PROTOINFO_TCP_MAX + 1); |
| } |
| |
| static int tcp_nlattr_tuple_size(void) |
| { |
| return nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1); |
| } |
| #endif |
| |
| #ifdef CONFIG_SYSCTL |
| static unsigned int tcp_sysctl_table_users; |
| static struct ctl_table_header *tcp_sysctl_header; |
| static struct ctl_table tcp_sysctl_table[] = { |
| { |
| .procname = "nf_conntrack_tcp_timeout_syn_sent", |
| .data = &tcp_timeouts[TCP_CONNTRACK_SYN_SENT], |
| .maxlen = sizeof(unsigned int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec_jiffies, |
| }, |
| { |
| .procname = "nf_conntrack_tcp_timeout_syn_recv", |
| .data = &tcp_timeouts[TCP_CONNTRACK_SYN_RECV], |
| .maxlen = sizeof(unsigned int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec_jiffies, |
| }, |
| { |
| .procname = "nf_conntrack_tcp_timeout_established", |
| .data = &tcp_timeouts[TCP_CONNTRACK_ESTABLISHED], |
| .maxlen = sizeof(unsigned int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec_jiffies, |
| }, |
| { |
| .procname = "nf_conntrack_tcp_timeout_fin_wait", |
| .data = &tcp_timeouts[TCP_CONNTRACK_FIN_WAIT], |
| .maxlen = sizeof(unsigned int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec_jiffies, |
| }, |
| { |
| .procname = "nf_conntrack_tcp_timeout_close_wait", |
| .data = &tcp_timeouts[TCP_CONNTRACK_CLOSE_WAIT], |
| .maxlen = sizeof(unsigned int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec_jiffies, |
| }, |
| { |
| .procname = "nf_conntrack_tcp_timeout_last_ack", |
| .data = &tcp_timeouts[TCP_CONNTRACK_LAST_ACK], |
| .maxlen = sizeof(unsigned int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec_jiffies, |
| }, |
| { |
| .procname = "nf_conntrack_tcp_timeout_time_wait", |
| .data = &tcp_timeouts[TCP_CONNTRACK_TIME_WAIT], |
| .maxlen = sizeof(unsigned int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec_jiffies, |
| }, |
| { |
| .procname = "nf_conntrack_tcp_timeout_close", |
| .data = &tcp_timeouts[TCP_CONNTRACK_CLOSE], |
| .maxlen = sizeof(unsigned int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec_jiffies, |
| }, |
| { |
| .procname = "nf_conntrack_tcp_timeout_max_retrans", |
| .data = &nf_ct_tcp_timeout_max_retrans, |
| .maxlen = sizeof(unsigned int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec_jiffies, |
| }, |
| { |
| .procname = "nf_conntrack_tcp_timeout_unacknowledged", |
| .data = &nf_ct_tcp_timeout_unacknowledged, |
| .maxlen = sizeof(unsigned int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec_jiffies, |
| }, |
| { |
| .procname = "nf_conntrack_tcp_loose", |
| .data = &nf_ct_tcp_loose, |
| .maxlen = sizeof(unsigned int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec, |
| }, |
| { |
| .procname = "nf_conntrack_tcp_no_window_check", |
| .data = &nf_ct_tcp_no_window_check, |
| .maxlen = sizeof(unsigned int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec, |
| }, |
| { |
| .procname = "nf_conntrack_tcp_be_liberal", |
| .data = &nf_ct_tcp_be_liberal, |
| .maxlen = sizeof(unsigned int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec, |
| }, |
| { |
| .procname = "nf_conntrack_tcp_max_retrans", |
| .data = &nf_ct_tcp_max_retrans, |
| .maxlen = sizeof(unsigned int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec, |
| }, |
| { } |
| }; |
| |
| #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT |
| static struct ctl_table tcp_compat_sysctl_table[] = { |
| { |
| .procname = "ip_conntrack_tcp_timeout_syn_sent", |
| .data = &tcp_timeouts[TCP_CONNTRACK_SYN_SENT], |
| .maxlen = sizeof(unsigned int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec_jiffies, |
| }, |
| { |
| .procname = "ip_conntrack_tcp_timeout_syn_sent2", |
| .data = &tcp_timeouts[TCP_CONNTRACK_SYN_SENT2], |
| .maxlen = sizeof(unsigned int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec_jiffies, |
| }, |
| { |
| .procname = "ip_conntrack_tcp_timeout_syn_recv", |
| .data = &tcp_timeouts[TCP_CONNTRACK_SYN_RECV], |
| .maxlen = sizeof(unsigned int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec_jiffies, |
| }, |
| { |
| .procname = "ip_conntrack_tcp_timeout_established", |
| .data = &tcp_timeouts[TCP_CONNTRACK_ESTABLISHED], |
| .maxlen = sizeof(unsigned int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec_jiffies, |
| }, |
| { |
| .procname = "ip_conntrack_tcp_timeout_fin_wait", |
| .data = &tcp_timeouts[TCP_CONNTRACK_FIN_WAIT], |
| .maxlen = sizeof(unsigned int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec_jiffies, |
| }, |
| { |
| .procname = "ip_conntrack_tcp_timeout_close_wait", |
| .data = &tcp_timeouts[TCP_CONNTRACK_CLOSE_WAIT], |
| .maxlen = sizeof(unsigned int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec_jiffies, |
| }, |
| { |
| .procname = "ip_conntrack_tcp_timeout_last_ack", |
| .data = &tcp_timeouts[TCP_CONNTRACK_LAST_ACK], |
| .maxlen = sizeof(unsigned int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec_jiffies, |
| }, |
| { |
| .procname = "ip_conntrack_tcp_timeout_time_wait", |
| .data = &tcp_timeouts[TCP_CONNTRACK_TIME_WAIT], |
| .maxlen = sizeof(unsigned int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec_jiffies, |
| }, |
| { |
| .procname = "ip_conntrack_tcp_timeout_close", |
| .data = &tcp_timeouts[TCP_CONNTRACK_CLOSE], |
| .maxlen = sizeof(unsigned int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec_jiffies, |
| }, |
| { |
| .procname = "ip_conntrack_tcp_timeout_max_retrans", |
| .data = &nf_ct_tcp_timeout_max_retrans, |
| .maxlen = sizeof(unsigned int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec_jiffies, |
| }, |
| { |
| .procname = "ip_conntrack_tcp_loose", |
| .data = &nf_ct_tcp_loose, |
| .maxlen = sizeof(unsigned int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec, |
| }, |
| { |
| .procname = "ip_conntrack_tcp_be_liberal", |
| .data = &nf_ct_tcp_be_liberal, |
| .maxlen = sizeof(unsigned int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec, |
| }, |
| { |
| .procname = "ip_conntrack_tcp_max_retrans", |
| .data = &nf_ct_tcp_max_retrans, |
| .maxlen = sizeof(unsigned int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec, |
| }, |
| { } |
| }; |
| #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */ |
| #endif /* CONFIG_SYSCTL */ |
| |
| struct nf_conntrack_l4proto nf_conntrack_l4proto_tcp4 __read_mostly = |
| { |
| .l3proto = PF_INET, |
| .l4proto = IPPROTO_TCP, |
| .name = "tcp", |
| .pkt_to_tuple = tcp_pkt_to_tuple, |
| .invert_tuple = tcp_invert_tuple, |
| .print_tuple = tcp_print_tuple, |
| .print_conntrack = tcp_print_conntrack, |
| .packet = tcp_packet, |
| .new = tcp_new, |
| .error = tcp_error, |
| #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) |
| .to_nlattr = tcp_to_nlattr, |
| .nlattr_size = tcp_nlattr_size, |
| .from_nlattr = nlattr_to_tcp, |
| .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr, |
| .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple, |
| .nlattr_tuple_size = tcp_nlattr_tuple_size, |
| .nla_policy = nf_ct_port_nla_policy, |
| #endif |
| #ifdef CONFIG_SYSCTL |
| .ctl_table_users = &tcp_sysctl_table_users, |
| .ctl_table_header = &tcp_sysctl_header, |
| .ctl_table = tcp_sysctl_table, |
| #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT |
| .ctl_compat_table = tcp_compat_sysctl_table, |
| #endif |
| #endif |
| }; |
| EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_tcp4); |
| |
| struct nf_conntrack_l4proto nf_conntrack_l4proto_tcp6 __read_mostly = |
| { |
| .l3proto = PF_INET6, |
| .l4proto = IPPROTO_TCP, |
| .name = "tcp", |
| .pkt_to_tuple = tcp_pkt_to_tuple, |
| .invert_tuple = tcp_invert_tuple, |
| .print_tuple = tcp_print_tuple, |
| .print_conntrack = tcp_print_conntrack, |
| .packet = tcp_packet, |
| .new = tcp_new, |
| .error = tcp_error, |
| #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) |
| .to_nlattr = tcp_to_nlattr, |
| .nlattr_size = tcp_nlattr_size, |
| .from_nlattr = nlattr_to_tcp, |
| .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr, |
| .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple, |
| .nlattr_tuple_size = tcp_nlattr_tuple_size, |
| .nla_policy = nf_ct_port_nla_policy, |
| #endif |
| #ifdef CONFIG_SYSCTL |
| .ctl_table_users = &tcp_sysctl_table_users, |
| .ctl_table_header = &tcp_sysctl_header, |
| .ctl_table = tcp_sysctl_table, |
| #endif |
| }; |
| EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_tcp6); |