1 /* (C) 1999-2001 Paul `Rusty' Russell
2 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
3 * (C) 2002-2013 Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
4 * (C) 2006-2012 Patrick McHardy <kaber@trash.net>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
11 #include <linux/types.h>
12 #include <linux/timer.h>
13 #include <linux/module.h>
15 #include <linux/tcp.h>
16 #include <linux/spinlock.h>
17 #include <linux/skbuff.h>
18 #include <linux/ipv6.h>
19 #include <net/ip6_checksum.h>
20 #include <asm/unaligned.h>
24 #include <linux/netfilter.h>
25 #include <linux/netfilter_ipv4.h>
26 #include <linux/netfilter_ipv6.h>
27 #include <net/netfilter/nf_conntrack.h>
28 #include <net/netfilter/nf_conntrack_l4proto.h>
29 #include <net/netfilter/nf_conntrack_ecache.h>
30 #include <net/netfilter/nf_conntrack_seqadj.h>
31 #include <net/netfilter/nf_conntrack_synproxy.h>
32 #include <net/netfilter/nf_log.h>
33 #include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
34 #include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
36 /* "Be conservative in what you do,
37 be liberal in what you accept from others."
38 If it's non-zero, we mark only out of window RST segments as INVALID. */
39 static int nf_ct_tcp_be_liberal __read_mostly = 0;
41 /* If it is set to zero, we disable picking up already established
43 static int nf_ct_tcp_loose __read_mostly = 1;
45 /* Max number of the retransmitted packets without receiving an (acceptable)
46 ACK from the destination. If this number is reached, a shorter timer
48 static int nf_ct_tcp_max_retrans __read_mostly = 3;
50 /* FIXME: Examine ipfilter's timeouts and conntrack transitions more
51 closely. They're more complex. --RR */
53 static const char *const tcp_conntrack_names[] = {
67 #define MINS * 60 SECS
68 #define HOURS * 60 MINS
69 #define DAYS * 24 HOURS
71 static unsigned int tcp_timeouts[TCP_CONNTRACK_TIMEOUT_MAX] __read_mostly = {
72 [TCP_CONNTRACK_SYN_SENT] = 2 MINS,
73 [TCP_CONNTRACK_SYN_RECV] = 60 SECS,
74 [TCP_CONNTRACK_ESTABLISHED] = 5 DAYS,
75 [TCP_CONNTRACK_FIN_WAIT] = 2 MINS,
76 [TCP_CONNTRACK_CLOSE_WAIT] = 60 SECS,
77 [TCP_CONNTRACK_LAST_ACK] = 30 SECS,
78 [TCP_CONNTRACK_TIME_WAIT] = 2 MINS,
79 [TCP_CONNTRACK_CLOSE] = 10 SECS,
80 [TCP_CONNTRACK_SYN_SENT2] = 2 MINS,
81 /* RFC1122 says the R2 limit should be at least 100 seconds.
82 Linux uses 15 packets as limit, which corresponds
83 to ~13-30min depending on RTO. */
84 [TCP_CONNTRACK_RETRANS] = 5 MINS,
85 [TCP_CONNTRACK_UNACK] = 5 MINS,
88 #define sNO TCP_CONNTRACK_NONE
89 #define sSS TCP_CONNTRACK_SYN_SENT
90 #define sSR TCP_CONNTRACK_SYN_RECV
91 #define sES TCP_CONNTRACK_ESTABLISHED
92 #define sFW TCP_CONNTRACK_FIN_WAIT
93 #define sCW TCP_CONNTRACK_CLOSE_WAIT
94 #define sLA TCP_CONNTRACK_LAST_ACK
95 #define sTW TCP_CONNTRACK_TIME_WAIT
96 #define sCL TCP_CONNTRACK_CLOSE
97 #define sS2 TCP_CONNTRACK_SYN_SENT2
98 #define sIV TCP_CONNTRACK_MAX
99 #define sIG TCP_CONNTRACK_IGNORE
101 /* What TCP flags are set from RST/SYN/FIN/ACK. */
112 * The TCP state transition table needs a few words...
114 * We are the man in the middle. All the packets go through us
115 * but might get lost in transit to the destination.
116 * It is assumed that the destinations can't receive segments
119 * The checked segment is in window, but our windows are *not*
120 * equivalent with the ones of the sender/receiver. We always
121 * try to guess the state of the current sender.
123 * The meaning of the states are:
125 * NONE: initial state
126 * SYN_SENT: SYN-only packet seen
127 * SYN_SENT2: SYN-only packet seen from reply dir, simultaneous open
128 * SYN_RECV: SYN-ACK packet seen
129 * ESTABLISHED: ACK packet seen
130 * FIN_WAIT: FIN packet seen
131 * CLOSE_WAIT: ACK seen (after FIN)
132 * LAST_ACK: FIN seen (after FIN)
133 * TIME_WAIT: last ACK seen
134 * CLOSE: closed connection (RST)
136 * Packets marked as IGNORED (sIG):
137 * if they may be either invalid or valid
138 * and the receiver may send back a connection
139 * closing RST or a SYN/ACK.
141 * Packets marked as INVALID (sIV):
142 * if we regard them as truly invalid packets
144 static const u8 tcp_conntracks[2][6][TCP_CONNTRACK_MAX] = {
147 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
148 /*syn*/ { sSS, sSS, sIG, sIG, sIG, sIG, sIG, sSS, sSS, sS2 },
150 * sNO -> sSS Initialize a new connection
151 * sSS -> sSS Retransmitted SYN
152 * sS2 -> sS2 Late retransmitted SYN
154 * sES -> sIG Error: SYNs in window outside the SYN_SENT state
155 * are errors. Receiver will reply with RST
156 * and close the connection.
157 * Or we are not in sync and hold a dead connection.
161 * sTW -> sSS Reopened connection (RFC 1122).
164 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
165 /*synack*/ { sIV, sIV, sSR, sIV, sIV, sIV, sIV, sIV, sIV, sSR },
167 * sNO -> sIV Too late and no reason to do anything
168 * sSS -> sIV Client can't send SYN and then SYN/ACK
169 * sS2 -> sSR SYN/ACK sent to SYN2 in simultaneous open
170 * sSR -> sSR Late retransmitted SYN/ACK in simultaneous open
171 * sES -> sIV Invalid SYN/ACK packets sent by the client
178 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
179 /*fin*/ { sIV, sIV, sFW, sFW, sLA, sLA, sLA, sTW, sCL, sIV },
181 * sNO -> sIV Too late and no reason to do anything...
182 * sSS -> sIV Client migth not send FIN in this state:
183 * we enforce waiting for a SYN/ACK reply first.
185 * sSR -> sFW Close started.
187 * sFW -> sLA FIN seen in both directions, waiting for
189 * Migth be a retransmitted FIN as well...
191 * sLA -> sLA Retransmitted FIN. Remain in the same state.
195 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
196 /*ack*/ { sES, sIV, sES, sES, sCW, sCW, sTW, sTW, sCL, sIV },
198 * sNO -> sES Assumed.
199 * sSS -> sIV ACK is invalid: we haven't seen a SYN/ACK yet.
201 * sSR -> sES Established state is reached.
203 * sFW -> sCW Normal close request answered by ACK.
205 * sLA -> sTW Last ACK detected (RFC5961 challenged)
206 * sTW -> sTW Retransmitted last ACK. Remain in the same state.
209 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
210 /*rst*/ { sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL },
211 /*none*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV }
215 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
216 /*syn*/ { sIV, sS2, sIV, sIV, sIV, sIV, sIV, sSS, sIV, sS2 },
218 * sNO -> sIV Never reached.
219 * sSS -> sS2 Simultaneous open
220 * sS2 -> sS2 Retransmitted simultaneous SYN
221 * sSR -> sIV Invalid SYN packets sent by the server
226 * sTW -> sSS Reopened connection, but server may have switched role
229 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
230 /*synack*/ { sIV, sSR, sIG, sIG, sIG, sIG, sIG, sIG, sIG, sSR },
232 * sSS -> sSR Standard open.
233 * sS2 -> sSR Simultaneous open
234 * sSR -> sIG Retransmitted SYN/ACK, ignore it.
235 * sES -> sIG Late retransmitted SYN/ACK?
236 * sFW -> sIG Might be SYN/ACK answering ignored SYN
242 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
243 /*fin*/ { sIV, sIV, sFW, sFW, sLA, sLA, sLA, sTW, sCL, sIV },
245 * sSS -> sIV Server might not send FIN in this state.
247 * sSR -> sFW Close started.
249 * sFW -> sLA FIN seen in both directions.
251 * sLA -> sLA Retransmitted FIN.
255 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
256 /*ack*/ { sIV, sIG, sSR, sES, sCW, sCW, sTW, sTW, sCL, sIG },
258 * sSS -> sIG Might be a half-open connection.
260 * sSR -> sSR Might answer late resent SYN.
262 * sFW -> sCW Normal close request answered by ACK.
264 * sLA -> sTW Last ACK detected (RFC5961 challenged)
265 * sTW -> sTW Retransmitted last ACK.
268 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
269 /*rst*/ { sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL },
270 /*none*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV }
274 static inline struct nf_tcp_net *tcp_pernet(struct net *net)
276 return &net->ct.nf_ct_proto.tcp;
279 static bool tcp_pkt_to_tuple(const struct sk_buff *skb, unsigned int dataoff,
280 struct net *net, struct nf_conntrack_tuple *tuple)
282 const struct tcphdr *hp;
285 /* Actually only need first 4 bytes to get ports. */
286 hp = skb_header_pointer(skb, dataoff, 4, &_hdr);
290 tuple->src.u.tcp.port = hp->source;
291 tuple->dst.u.tcp.port = hp->dest;
296 static bool tcp_invert_tuple(struct nf_conntrack_tuple *tuple,
297 const struct nf_conntrack_tuple *orig)
299 tuple->src.u.tcp.port = orig->dst.u.tcp.port;
300 tuple->dst.u.tcp.port = orig->src.u.tcp.port;
304 /* Print out the per-protocol part of the tuple. */
305 static void tcp_print_tuple(struct seq_file *s,
306 const struct nf_conntrack_tuple *tuple)
308 seq_printf(s, "sport=%hu dport=%hu ",
309 ntohs(tuple->src.u.tcp.port),
310 ntohs(tuple->dst.u.tcp.port));
313 /* Print out the private part of the conntrack. */
314 static void tcp_print_conntrack(struct seq_file *s, struct nf_conn *ct)
316 seq_printf(s, "%s ", tcp_conntrack_names[ct->proto.tcp.state]);
319 static unsigned int get_conntrack_index(const struct tcphdr *tcph)
321 if (tcph->rst) return TCP_RST_SET;
322 else if (tcph->syn) return (tcph->ack ? TCP_SYNACK_SET : TCP_SYN_SET);
323 else if (tcph->fin) return TCP_FIN_SET;
324 else if (tcph->ack) return TCP_ACK_SET;
325 else return TCP_NONE_SET;
328 /* TCP connection tracking based on 'Real Stateful TCP Packet Filtering
329 in IP Filter' by Guido van Rooij.
331 http://www.sane.nl/events/sane2000/papers.html
332 http://www.darkart.com/mirrors/www.obfuscation.org/ipf/
334 The boundaries and the conditions are changed according to RFC793:
335 the packet must intersect the window (i.e. segments may be
336 after the right or before the left edge) and thus receivers may ACK
337 segments after the right edge of the window.
339 td_maxend = max(sack + max(win,1)) seen in reply packets
340 td_maxwin = max(max(win, 1)) + (sack - ack) seen in sent packets
341 td_maxwin += seq + len - sender.td_maxend
342 if seq + len > sender.td_maxend
343 td_end = max(seq + len) seen in sent packets
345 I. Upper bound for valid data: seq <= sender.td_maxend
346 II. Lower bound for valid data: seq + len >= sender.td_end - receiver.td_maxwin
347 III. Upper bound for valid (s)ack: sack <= receiver.td_end
348 IV. Lower bound for valid (s)ack: sack >= receiver.td_end - MAXACKWINDOW
350 where sack is the highest right edge of sack block found in the packet
351 or ack in the case of packet without SACK option.
353 The upper bound limit for a valid (s)ack is not ignored -
354 we doesn't have to deal with fragments.
357 static inline __u32 segment_seq_plus_len(__u32 seq,
359 unsigned int dataoff,
360 const struct tcphdr *tcph)
362 /* XXX Should I use payload length field in IP/IPv6 header ?
364 return (seq + len - dataoff - tcph->doff*4
365 + (tcph->syn ? 1 : 0) + (tcph->fin ? 1 : 0));
368 /* Fixme: what about big packets? */
369 #define MAXACKWINCONST 66000
370 #define MAXACKWINDOW(sender) \
371 ((sender)->td_maxwin > MAXACKWINCONST ? (sender)->td_maxwin \
375 * Simplified tcp_parse_options routine from tcp_input.c
377 static void tcp_options(const struct sk_buff *skb,
378 unsigned int dataoff,
379 const struct tcphdr *tcph,
380 struct ip_ct_tcp_state *state)
382 unsigned char buff[(15 * 4) - sizeof(struct tcphdr)];
383 const unsigned char *ptr;
384 int length = (tcph->doff*4) - sizeof(struct tcphdr);
389 ptr = skb_header_pointer(skb, dataoff + sizeof(struct tcphdr),
394 state->flags &= IP_CT_TCP_FLAG_BE_LIBERAL;
403 case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */
410 if (opsize < 2) /* "silly options" */
413 return; /* don't parse partial options */
415 if (opcode == TCPOPT_SACK_PERM
416 && opsize == TCPOLEN_SACK_PERM)
417 state->flags |= IP_CT_TCP_FLAG_SACK_PERM;
418 else if (opcode == TCPOPT_WINDOW
419 && opsize == TCPOLEN_WINDOW) {
420 state->td_scale = *(u_int8_t *)ptr;
422 if (state->td_scale > 14) {
424 state->td_scale = 14;
427 IP_CT_TCP_FLAG_WINDOW_SCALE;
435 static void tcp_sack(const struct sk_buff *skb, unsigned int dataoff,
436 const struct tcphdr *tcph, __u32 *sack)
438 unsigned char buff[(15 * 4) - sizeof(struct tcphdr)];
439 const unsigned char *ptr;
440 int length = (tcph->doff*4) - sizeof(struct tcphdr);
446 ptr = skb_header_pointer(skb, dataoff + sizeof(struct tcphdr),
450 /* Fast path for timestamp-only option */
451 if (length == TCPOLEN_TSTAMP_ALIGNED
452 && *(__be32 *)ptr == htonl((TCPOPT_NOP << 24)
454 | (TCPOPT_TIMESTAMP << 8)
455 | TCPOLEN_TIMESTAMP))
465 case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */
472 if (opsize < 2) /* "silly options" */
475 return; /* don't parse partial options */
477 if (opcode == TCPOPT_SACK
478 && opsize >= (TCPOLEN_SACK_BASE
479 + TCPOLEN_SACK_PERBLOCK)
480 && !((opsize - TCPOLEN_SACK_BASE)
481 % TCPOLEN_SACK_PERBLOCK)) {
483 i < (opsize - TCPOLEN_SACK_BASE);
484 i += TCPOLEN_SACK_PERBLOCK) {
485 tmp = get_unaligned_be32((__be32 *)(ptr+i)+1);
487 if (after(tmp, *sack))
498 static bool tcp_in_window(const struct nf_conn *ct,
499 struct ip_ct_tcp *state,
500 enum ip_conntrack_dir dir,
502 const struct sk_buff *skb,
503 unsigned int dataoff,
504 const struct tcphdr *tcph,
507 struct net *net = nf_ct_net(ct);
508 struct nf_tcp_net *tn = tcp_pernet(net);
509 struct ip_ct_tcp_state *sender = &state->seen[dir];
510 struct ip_ct_tcp_state *receiver = &state->seen[!dir];
511 const struct nf_conntrack_tuple *tuple = &ct->tuplehash[dir].tuple;
512 __u32 seq, ack, sack, end, win, swin;
514 bool res, in_recv_win;
517 * Get the required data from the packet.
519 seq = ntohl(tcph->seq);
520 ack = sack = ntohl(tcph->ack_seq);
521 win = ntohs(tcph->window);
522 end = segment_seq_plus_len(seq, skb->len, dataoff, tcph);
524 if (receiver->flags & IP_CT_TCP_FLAG_SACK_PERM)
525 tcp_sack(skb, dataoff, tcph, &sack);
527 /* Take into account NAT sequence number mangling */
528 receiver_offset = nf_ct_seq_offset(ct, !dir, ack - 1);
529 ack -= receiver_offset;
530 sack -= receiver_offset;
532 pr_debug("tcp_in_window: START\n");
533 pr_debug("tcp_in_window: ");
534 nf_ct_dump_tuple(tuple);
535 pr_debug("seq=%u ack=%u+(%d) sack=%u+(%d) win=%u end=%u\n",
536 seq, ack, receiver_offset, sack, receiver_offset, win, end);
537 pr_debug("tcp_in_window: sender end=%u maxend=%u maxwin=%u scale=%i "
538 "receiver end=%u maxend=%u maxwin=%u scale=%i\n",
539 sender->td_end, sender->td_maxend, sender->td_maxwin,
541 receiver->td_end, receiver->td_maxend, receiver->td_maxwin,
544 if (sender->td_maxwin == 0) {
546 * Initialize sender data.
550 * SYN-ACK in reply to a SYN
551 * or SYN from reply direction in simultaneous open.
554 sender->td_maxend = end;
555 sender->td_maxwin = (win == 0 ? 1 : win);
557 tcp_options(skb, dataoff, tcph, sender);
560 * Both sides must send the Window Scale option
561 * to enable window scaling in either direction.
563 if (!(sender->flags & IP_CT_TCP_FLAG_WINDOW_SCALE
564 && receiver->flags & IP_CT_TCP_FLAG_WINDOW_SCALE))
566 receiver->td_scale = 0;
568 /* Simultaneous open */
572 * We are in the middle of a connection,
573 * its history is lost for us.
574 * Let's try to use the data from the packet.
576 sender->td_end = end;
577 swin = win << sender->td_scale;
578 sender->td_maxwin = (swin == 0 ? 1 : swin);
579 sender->td_maxend = end + sender->td_maxwin;
581 * We haven't seen traffic in the other direction yet
582 * but we have to tweak window tracking to pass III
583 * and IV until that happens.
585 if (receiver->td_maxwin == 0)
586 receiver->td_end = receiver->td_maxend = sack;
588 } else if (((state->state == TCP_CONNTRACK_SYN_SENT
589 && dir == IP_CT_DIR_ORIGINAL)
590 || (state->state == TCP_CONNTRACK_SYN_RECV
591 && dir == IP_CT_DIR_REPLY))
592 && after(end, sender->td_end)) {
594 * RFC 793: "if a TCP is reinitialized ... then it need
595 * not wait at all; it must only be sure to use sequence
596 * numbers larger than those recently used."
599 sender->td_maxend = end;
600 sender->td_maxwin = (win == 0 ? 1 : win);
602 tcp_options(skb, dataoff, tcph, sender);
607 * If there is no ACK, just pretend it was set and OK.
609 ack = sack = receiver->td_end;
610 } else if (((tcp_flag_word(tcph) & (TCP_FLAG_ACK|TCP_FLAG_RST)) ==
611 (TCP_FLAG_ACK|TCP_FLAG_RST))
614 * Broken TCP stacks, that set ACK in RST packets as well
615 * with zero ack value.
617 ack = sack = receiver->td_end;
620 if (tcph->rst && seq == 0 && state->state == TCP_CONNTRACK_SYN_SENT)
622 * RST sent answering SYN.
624 seq = end = sender->td_end;
626 pr_debug("tcp_in_window: ");
627 nf_ct_dump_tuple(tuple);
628 pr_debug("seq=%u ack=%u+(%d) sack=%u+(%d) win=%u end=%u\n",
629 seq, ack, receiver_offset, sack, receiver_offset, win, end);
630 pr_debug("tcp_in_window: sender end=%u maxend=%u maxwin=%u scale=%i "
631 "receiver end=%u maxend=%u maxwin=%u scale=%i\n",
632 sender->td_end, sender->td_maxend, sender->td_maxwin,
634 receiver->td_end, receiver->td_maxend, receiver->td_maxwin,
637 /* Is the ending sequence in the receive window (if available)? */
638 in_recv_win = !receiver->td_maxwin ||
639 after(end, sender->td_end - receiver->td_maxwin - 1);
641 pr_debug("tcp_in_window: I=%i II=%i III=%i IV=%i\n",
642 before(seq, sender->td_maxend + 1),
643 (in_recv_win ? 1 : 0),
644 before(sack, receiver->td_end + 1),
645 after(sack, receiver->td_end - MAXACKWINDOW(sender) - 1));
647 if (before(seq, sender->td_maxend + 1) &&
649 before(sack, receiver->td_end + 1) &&
650 after(sack, receiver->td_end - MAXACKWINDOW(sender) - 1)) {
652 * Take into account window scaling (RFC 1323).
655 win <<= sender->td_scale;
658 * Update sender data.
660 swin = win + (sack - ack);
661 if (sender->td_maxwin < swin)
662 sender->td_maxwin = swin;
663 if (after(end, sender->td_end)) {
664 sender->td_end = end;
665 sender->flags |= IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED;
668 if (!(sender->flags & IP_CT_TCP_FLAG_MAXACK_SET)) {
669 sender->td_maxack = ack;
670 sender->flags |= IP_CT_TCP_FLAG_MAXACK_SET;
671 } else if (after(ack, sender->td_maxack))
672 sender->td_maxack = ack;
676 * Update receiver data.
678 if (receiver->td_maxwin != 0 && after(end, sender->td_maxend))
679 receiver->td_maxwin += end - sender->td_maxend;
680 if (after(sack + win, receiver->td_maxend - 1)) {
681 receiver->td_maxend = sack + win;
683 receiver->td_maxend++;
685 if (ack == receiver->td_end)
686 receiver->flags &= ~IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED;
689 * Check retransmissions.
691 if (index == TCP_ACK_SET) {
692 if (state->last_dir == dir
693 && state->last_seq == seq
694 && state->last_ack == ack
695 && state->last_end == end
696 && state->last_win == win)
699 state->last_dir = dir;
700 state->last_seq = seq;
701 state->last_ack = ack;
702 state->last_end = end;
703 state->last_win = win;
710 if (sender->flags & IP_CT_TCP_FLAG_BE_LIBERAL ||
713 if (!res && LOG_INVALID(net, IPPROTO_TCP))
714 nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
716 before(seq, sender->td_maxend + 1) ?
718 before(sack, receiver->td_end + 1) ?
719 after(sack, receiver->td_end - MAXACKWINDOW(sender) - 1) ? "BUG"
720 : "ACK is under the lower bound (possible overly delayed ACK)"
721 : "ACK is over the upper bound (ACKed data not seen yet)"
722 : "SEQ is under the lower bound (already ACKed data retransmitted)"
723 : "SEQ is over the upper bound (over the window of the receiver)");
726 pr_debug("tcp_in_window: res=%u sender end=%u maxend=%u maxwin=%u "
727 "receiver end=%u maxend=%u maxwin=%u\n",
728 res, sender->td_end, sender->td_maxend, sender->td_maxwin,
729 receiver->td_end, receiver->td_maxend, receiver->td_maxwin);
734 /* table of valid flag combinations - PUSH, ECE and CWR are always valid */
735 static const u8 tcp_valid_flags[(TCPHDR_FIN|TCPHDR_SYN|TCPHDR_RST|TCPHDR_ACK|
739 [TCPHDR_SYN|TCPHDR_URG] = 1,
740 [TCPHDR_SYN|TCPHDR_ACK] = 1,
742 [TCPHDR_RST|TCPHDR_ACK] = 1,
743 [TCPHDR_FIN|TCPHDR_ACK] = 1,
744 [TCPHDR_FIN|TCPHDR_ACK|TCPHDR_URG] = 1,
746 [TCPHDR_ACK|TCPHDR_URG] = 1,
749 /* Protect conntrack agaist broken packets. Code taken from ipt_unclean.c. */
750 static int tcp_error(struct net *net, struct nf_conn *tmpl,
752 unsigned int dataoff,
753 enum ip_conntrack_info *ctinfo,
755 unsigned int hooknum)
757 const struct tcphdr *th;
759 unsigned int tcplen = skb->len - dataoff;
762 /* Smaller that minimal TCP header? */
763 th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph);
765 if (LOG_INVALID(net, IPPROTO_TCP))
766 nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
767 "nf_ct_tcp: short packet ");
771 /* Not whole TCP header or malformed packet */
772 if (th->doff*4 < sizeof(struct tcphdr) || tcplen < th->doff*4) {
773 if (LOG_INVALID(net, IPPROTO_TCP))
774 nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
775 "nf_ct_tcp: truncated/malformed packet ");
779 /* Checksum invalid? Ignore.
780 * We skip checking packets on the outgoing path
781 * because the checksum is assumed to be correct.
783 /* FIXME: Source route IP option packets --RR */
784 if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
785 nf_checksum(skb, hooknum, dataoff, IPPROTO_TCP, pf)) {
786 if (LOG_INVALID(net, IPPROTO_TCP))
787 nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
788 "nf_ct_tcp: bad TCP checksum ");
792 /* Check TCP flags. */
793 tcpflags = (tcp_flag_byte(th) & ~(TCPHDR_ECE|TCPHDR_CWR|TCPHDR_PSH));
794 if (!tcp_valid_flags[tcpflags]) {
795 if (LOG_INVALID(net, IPPROTO_TCP))
796 nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
797 "nf_ct_tcp: invalid TCP flag combination ");
804 static unsigned int *tcp_get_timeouts(struct net *net)
806 return tcp_pernet(net)->timeouts;
809 static void nf_ct_tcp_state_reset(struct ip_ct_tcp_state *state)
812 state->td_maxend = 0;
813 state->td_maxwin = 0;
814 state->td_maxack = 0;
816 state->flags &= IP_CT_TCP_FLAG_BE_LIBERAL;
819 /* Returns verdict for packet, or -1 for invalid. */
820 static int tcp_packet(struct nf_conn *ct,
821 const struct sk_buff *skb,
822 unsigned int dataoff,
823 enum ip_conntrack_info ctinfo,
825 unsigned int hooknum,
826 unsigned int *timeouts)
828 struct net *net = nf_ct_net(ct);
829 struct nf_tcp_net *tn = tcp_pernet(net);
830 struct nf_conntrack_tuple *tuple;
831 enum tcp_conntrack new_state, old_state;
832 enum ip_conntrack_dir dir;
833 const struct tcphdr *th;
835 unsigned long timeout;
838 th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph);
841 spin_lock_bh(&ct->lock);
842 old_state = ct->proto.tcp.state;
843 dir = CTINFO2DIR(ctinfo);
844 index = get_conntrack_index(th);
845 new_state = tcp_conntracks[dir][index][old_state];
846 tuple = &ct->tuplehash[dir].tuple;
849 case TCP_CONNTRACK_SYN_SENT:
850 if (old_state < TCP_CONNTRACK_TIME_WAIT)
852 /* RFC 1122: "When a connection is closed actively,
853 * it MUST linger in TIME-WAIT state for a time 2xMSL
854 * (Maximum Segment Lifetime). However, it MAY accept
855 * a new SYN from the remote TCP to reopen the connection
856 * directly from TIME-WAIT state, if..."
857 * We ignore the conditions because we are in the
858 * TIME-WAIT state anyway.
860 * Handle aborted connections: we and the server
861 * think there is an existing connection but the client
862 * aborts it and starts a new one.
864 if (((ct->proto.tcp.seen[dir].flags
865 | ct->proto.tcp.seen[!dir].flags)
866 & IP_CT_TCP_FLAG_CLOSE_INIT)
867 || (ct->proto.tcp.last_dir == dir
868 && ct->proto.tcp.last_index == TCP_RST_SET)) {
869 /* Attempt to reopen a closed/aborted connection.
870 * Delete this connection and look up again. */
871 spin_unlock_bh(&ct->lock);
873 /* Only repeat if we can actually remove the timer.
874 * Destruction may already be in progress in process
875 * context and we must give it a chance to terminate.
882 case TCP_CONNTRACK_IGNORE:
885 * Our connection entry may be out of sync, so ignore
886 * packets which may signal the real connection between
887 * the client and the server.
890 * b) SYN/ACK in REPLY
891 * c) ACK in reply direction after initial SYN in original.
893 * If the ignored packet is invalid, the receiver will send
894 * a RST we'll catch below.
896 if (index == TCP_SYNACK_SET
897 && ct->proto.tcp.last_index == TCP_SYN_SET
898 && ct->proto.tcp.last_dir != dir
899 && ntohl(th->ack_seq) == ct->proto.tcp.last_end) {
900 /* b) This SYN/ACK acknowledges a SYN that we earlier
901 * ignored as invalid. This means that the client and
902 * the server are both in sync, while the firewall is
903 * not. We get in sync from the previously annotated
906 old_state = TCP_CONNTRACK_SYN_SENT;
907 new_state = TCP_CONNTRACK_SYN_RECV;
908 ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_end =
909 ct->proto.tcp.last_end;
910 ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_maxend =
911 ct->proto.tcp.last_end;
912 ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_maxwin =
913 ct->proto.tcp.last_win == 0 ?
914 1 : ct->proto.tcp.last_win;
915 ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_scale =
916 ct->proto.tcp.last_wscale;
917 ct->proto.tcp.last_flags &= ~IP_CT_EXP_CHALLENGE_ACK;
918 ct->proto.tcp.seen[ct->proto.tcp.last_dir].flags =
919 ct->proto.tcp.last_flags;
920 nf_ct_tcp_state_reset(&ct->proto.tcp.seen[dir]);
923 ct->proto.tcp.last_index = index;
924 ct->proto.tcp.last_dir = dir;
925 ct->proto.tcp.last_seq = ntohl(th->seq);
926 ct->proto.tcp.last_end =
927 segment_seq_plus_len(ntohl(th->seq), skb->len, dataoff, th);
928 ct->proto.tcp.last_win = ntohs(th->window);
930 /* a) This is a SYN in ORIGINAL. The client and the server
931 * may be in sync but we are not. In that case, we annotate
932 * the TCP options and let the packet go through. If it is a
933 * valid SYN packet, the server will reply with a SYN/ACK, and
934 * then we'll get in sync. Otherwise, the server potentially
935 * responds with a challenge ACK if implementing RFC5961.
937 if (index == TCP_SYN_SET && dir == IP_CT_DIR_ORIGINAL) {
938 struct ip_ct_tcp_state seen = {};
940 ct->proto.tcp.last_flags =
941 ct->proto.tcp.last_wscale = 0;
942 tcp_options(skb, dataoff, th, &seen);
943 if (seen.flags & IP_CT_TCP_FLAG_WINDOW_SCALE) {
944 ct->proto.tcp.last_flags |=
945 IP_CT_TCP_FLAG_WINDOW_SCALE;
946 ct->proto.tcp.last_wscale = seen.td_scale;
948 if (seen.flags & IP_CT_TCP_FLAG_SACK_PERM) {
949 ct->proto.tcp.last_flags |=
950 IP_CT_TCP_FLAG_SACK_PERM;
952 /* Mark the potential for RFC5961 challenge ACK,
953 * this pose a special problem for LAST_ACK state
954 * as ACK is intrepretated as ACKing last FIN.
956 if (old_state == TCP_CONNTRACK_LAST_ACK)
957 ct->proto.tcp.last_flags |=
958 IP_CT_EXP_CHALLENGE_ACK;
960 spin_unlock_bh(&ct->lock);
961 if (LOG_INVALID(net, IPPROTO_TCP))
962 nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
963 "nf_ct_tcp: invalid packet ignored in "
964 "state %s ", tcp_conntrack_names[old_state]);
966 case TCP_CONNTRACK_MAX:
967 /* Special case for SYN proxy: when the SYN to the server or
968 * the SYN/ACK from the server is lost, the client may transmit
969 * a keep-alive packet while in SYN_SENT state. This needs to
970 * be associated with the original conntrack entry in order to
971 * generate a new SYN with the correct sequence number.
973 if (nfct_synproxy(ct) && old_state == TCP_CONNTRACK_SYN_SENT &&
974 index == TCP_ACK_SET && dir == IP_CT_DIR_ORIGINAL &&
975 ct->proto.tcp.last_dir == IP_CT_DIR_ORIGINAL &&
976 ct->proto.tcp.seen[dir].td_end - 1 == ntohl(th->seq)) {
977 pr_debug("nf_ct_tcp: SYN proxy client keep alive\n");
978 spin_unlock_bh(&ct->lock);
983 pr_debug("nf_ct_tcp: Invalid dir=%i index=%u ostate=%u\n",
984 dir, get_conntrack_index(th), old_state);
985 spin_unlock_bh(&ct->lock);
986 if (LOG_INVALID(net, IPPROTO_TCP))
987 nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
988 "nf_ct_tcp: invalid state ");
990 case TCP_CONNTRACK_TIME_WAIT:
991 /* RFC5961 compliance cause stack to send "challenge-ACK"
992 * e.g. in response to spurious SYNs. Conntrack MUST
993 * not believe this ACK is acking last FIN.
995 if (old_state == TCP_CONNTRACK_LAST_ACK &&
996 index == TCP_ACK_SET &&
997 ct->proto.tcp.last_dir != dir &&
998 ct->proto.tcp.last_index == TCP_SYN_SET &&
999 (ct->proto.tcp.last_flags & IP_CT_EXP_CHALLENGE_ACK)) {
1000 /* Detected RFC5961 challenge ACK */
1001 ct->proto.tcp.last_flags &= ~IP_CT_EXP_CHALLENGE_ACK;
1002 spin_unlock_bh(&ct->lock);
1003 if (LOG_INVALID(net, IPPROTO_TCP))
1004 nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
1005 "nf_ct_tcp: challenge-ACK ignored ");
1006 return NF_ACCEPT; /* Don't change state */
1009 case TCP_CONNTRACK_CLOSE:
1010 if (index == TCP_RST_SET
1011 && (ct->proto.tcp.seen[!dir].flags & IP_CT_TCP_FLAG_MAXACK_SET)
1012 && before(ntohl(th->seq), ct->proto.tcp.seen[!dir].td_maxack)) {
1014 spin_unlock_bh(&ct->lock);
1015 if (LOG_INVALID(net, IPPROTO_TCP))
1016 nf_log_packet(net, pf, 0, skb, NULL, NULL,
1017 NULL, "nf_ct_tcp: invalid RST ");
1020 if (index == TCP_RST_SET
1021 && ((test_bit(IPS_SEEN_REPLY_BIT, &ct->status)
1022 && ct->proto.tcp.last_index == TCP_SYN_SET)
1023 || (!test_bit(IPS_ASSURED_BIT, &ct->status)
1024 && ct->proto.tcp.last_index == TCP_ACK_SET))
1025 && ntohl(th->ack_seq) == ct->proto.tcp.last_end) {
1026 /* RST sent to invalid SYN or ACK we had let through
1027 * at a) and c) above:
1029 * a) SYN was in window then
1030 * c) we hold a half-open connection.
1032 * Delete our connection entry.
1033 * We skip window checking, because packet might ACK
1034 * segments we ignored. */
1037 /* Just fall through */
1039 /* Keep compilers happy. */
1043 if (!tcp_in_window(ct, &ct->proto.tcp, dir, index,
1044 skb, dataoff, th, pf)) {
1045 spin_unlock_bh(&ct->lock);
1049 /* From now on we have got in-window packets */
1050 ct->proto.tcp.last_index = index;
1051 ct->proto.tcp.last_dir = dir;
1053 pr_debug("tcp_conntracks: ");
1054 nf_ct_dump_tuple(tuple);
1055 pr_debug("syn=%i ack=%i fin=%i rst=%i old=%i new=%i\n",
1056 (th->syn ? 1 : 0), (th->ack ? 1 : 0),
1057 (th->fin ? 1 : 0), (th->rst ? 1 : 0),
1058 old_state, new_state);
1060 ct->proto.tcp.state = new_state;
1061 if (old_state != new_state
1062 && new_state == TCP_CONNTRACK_FIN_WAIT)
1063 ct->proto.tcp.seen[dir].flags |= IP_CT_TCP_FLAG_CLOSE_INIT;
1065 if (ct->proto.tcp.retrans >= tn->tcp_max_retrans &&
1066 timeouts[new_state] > timeouts[TCP_CONNTRACK_RETRANS])
1067 timeout = timeouts[TCP_CONNTRACK_RETRANS];
1068 else if ((ct->proto.tcp.seen[0].flags | ct->proto.tcp.seen[1].flags) &
1069 IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED &&
1070 timeouts[new_state] > timeouts[TCP_CONNTRACK_UNACK])
1071 timeout = timeouts[TCP_CONNTRACK_UNACK];
1073 timeout = timeouts[new_state];
1074 spin_unlock_bh(&ct->lock);
1076 if (new_state != old_state)
1077 nf_conntrack_event_cache(IPCT_PROTOINFO, ct);
1079 if (!test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
1080 /* If only reply is a RST, we can consider ourselves not to
1081 have an established connection: this is a fairly common
1082 problem case, so we can delete the conntrack
1083 immediately. --RR */
1085 nf_ct_kill_acct(ct, ctinfo, skb);
1088 /* ESTABLISHED without SEEN_REPLY, i.e. mid-connection
1089 * pickup with loose=1. Avoid large ESTABLISHED timeout.
1091 if (new_state == TCP_CONNTRACK_ESTABLISHED &&
1092 timeout > timeouts[TCP_CONNTRACK_UNACK])
1093 timeout = timeouts[TCP_CONNTRACK_UNACK];
1094 } else if (!test_bit(IPS_ASSURED_BIT, &ct->status)
1095 && (old_state == TCP_CONNTRACK_SYN_RECV
1096 || old_state == TCP_CONNTRACK_ESTABLISHED)
1097 && new_state == TCP_CONNTRACK_ESTABLISHED) {
1098 /* Set ASSURED if we see see valid ack in ESTABLISHED
1099 after SYN_RECV or a valid answer for a picked up
1101 set_bit(IPS_ASSURED_BIT, &ct->status);
1102 nf_conntrack_event_cache(IPCT_ASSURED, ct);
1104 nf_ct_refresh_acct(ct, ctinfo, skb, timeout);
1109 /* Called when a new connection for this protocol found. */
1110 static bool tcp_new(struct nf_conn *ct, const struct sk_buff *skb,
1111 unsigned int dataoff, unsigned int *timeouts)
1113 enum tcp_conntrack new_state;
1114 const struct tcphdr *th;
1115 struct tcphdr _tcph;
1116 struct net *net = nf_ct_net(ct);
1117 struct nf_tcp_net *tn = tcp_pernet(net);
1118 const struct ip_ct_tcp_state *sender = &ct->proto.tcp.seen[0];
1119 const struct ip_ct_tcp_state *receiver = &ct->proto.tcp.seen[1];
1121 th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph);
1124 /* Don't need lock here: this conntrack not in circulation yet */
1125 new_state = tcp_conntracks[0][get_conntrack_index(th)][TCP_CONNTRACK_NONE];
1127 /* Invalid: delete conntrack */
1128 if (new_state >= TCP_CONNTRACK_MAX) {
1129 pr_debug("nf_ct_tcp: invalid new deleting.\n");
1133 if (new_state == TCP_CONNTRACK_SYN_SENT) {
1134 memset(&ct->proto.tcp, 0, sizeof(ct->proto.tcp));
1136 ct->proto.tcp.seen[0].td_end =
1137 segment_seq_plus_len(ntohl(th->seq), skb->len,
1139 ct->proto.tcp.seen[0].td_maxwin = ntohs(th->window);
1140 if (ct->proto.tcp.seen[0].td_maxwin == 0)
1141 ct->proto.tcp.seen[0].td_maxwin = 1;
1142 ct->proto.tcp.seen[0].td_maxend =
1143 ct->proto.tcp.seen[0].td_end;
1145 tcp_options(skb, dataoff, th, &ct->proto.tcp.seen[0]);
1146 } else if (tn->tcp_loose == 0) {
1147 /* Don't try to pick up connections. */
1150 memset(&ct->proto.tcp, 0, sizeof(ct->proto.tcp));
1152 * We are in the middle of a connection,
1153 * its history is lost for us.
1154 * Let's try to use the data from the packet.
1156 ct->proto.tcp.seen[0].td_end =
1157 segment_seq_plus_len(ntohl(th->seq), skb->len,
1159 ct->proto.tcp.seen[0].td_maxwin = ntohs(th->window);
1160 if (ct->proto.tcp.seen[0].td_maxwin == 0)
1161 ct->proto.tcp.seen[0].td_maxwin = 1;
1162 ct->proto.tcp.seen[0].td_maxend =
1163 ct->proto.tcp.seen[0].td_end +
1164 ct->proto.tcp.seen[0].td_maxwin;
1166 /* We assume SACK and liberal window checking to handle
1168 ct->proto.tcp.seen[0].flags =
1169 ct->proto.tcp.seen[1].flags = IP_CT_TCP_FLAG_SACK_PERM |
1170 IP_CT_TCP_FLAG_BE_LIBERAL;
1173 /* tcp_packet will set them */
1174 ct->proto.tcp.last_index = TCP_NONE_SET;
1176 pr_debug("tcp_new: sender end=%u maxend=%u maxwin=%u scale=%i "
1177 "receiver end=%u maxend=%u maxwin=%u scale=%i\n",
1178 sender->td_end, sender->td_maxend, sender->td_maxwin,
1180 receiver->td_end, receiver->td_maxend, receiver->td_maxwin,
1181 receiver->td_scale);
1185 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
1187 #include <linux/netfilter/nfnetlink.h>
1188 #include <linux/netfilter/nfnetlink_conntrack.h>
1190 static int tcp_to_nlattr(struct sk_buff *skb, struct nlattr *nla,
1193 struct nlattr *nest_parms;
1194 struct nf_ct_tcp_flags tmp = {};
1196 spin_lock_bh(&ct->lock);
1197 nest_parms = nla_nest_start(skb, CTA_PROTOINFO_TCP | NLA_F_NESTED);
1199 goto nla_put_failure;
1201 if (nla_put_u8(skb, CTA_PROTOINFO_TCP_STATE, ct->proto.tcp.state) ||
1202 nla_put_u8(skb, CTA_PROTOINFO_TCP_WSCALE_ORIGINAL,
1203 ct->proto.tcp.seen[0].td_scale) ||
1204 nla_put_u8(skb, CTA_PROTOINFO_TCP_WSCALE_REPLY,
1205 ct->proto.tcp.seen[1].td_scale))
1206 goto nla_put_failure;
1208 tmp.flags = ct->proto.tcp.seen[0].flags;
1209 if (nla_put(skb, CTA_PROTOINFO_TCP_FLAGS_ORIGINAL,
1210 sizeof(struct nf_ct_tcp_flags), &tmp))
1211 goto nla_put_failure;
1213 tmp.flags = ct->proto.tcp.seen[1].flags;
1214 if (nla_put(skb, CTA_PROTOINFO_TCP_FLAGS_REPLY,
1215 sizeof(struct nf_ct_tcp_flags), &tmp))
1216 goto nla_put_failure;
1217 spin_unlock_bh(&ct->lock);
1219 nla_nest_end(skb, nest_parms);
1224 spin_unlock_bh(&ct->lock);
1228 static const struct nla_policy tcp_nla_policy[CTA_PROTOINFO_TCP_MAX+1] = {
1229 [CTA_PROTOINFO_TCP_STATE] = { .type = NLA_U8 },
1230 [CTA_PROTOINFO_TCP_WSCALE_ORIGINAL] = { .type = NLA_U8 },
1231 [CTA_PROTOINFO_TCP_WSCALE_REPLY] = { .type = NLA_U8 },
1232 [CTA_PROTOINFO_TCP_FLAGS_ORIGINAL] = { .len = sizeof(struct nf_ct_tcp_flags) },
1233 [CTA_PROTOINFO_TCP_FLAGS_REPLY] = { .len = sizeof(struct nf_ct_tcp_flags) },
1236 static int nlattr_to_tcp(struct nlattr *cda[], struct nf_conn *ct)
1238 struct nlattr *pattr = cda[CTA_PROTOINFO_TCP];
1239 struct nlattr *tb[CTA_PROTOINFO_TCP_MAX+1];
1242 /* updates could not contain anything about the private
1243 * protocol info, in that case skip the parsing */
1247 err = nla_parse_nested(tb, CTA_PROTOINFO_TCP_MAX, pattr, tcp_nla_policy);
1251 if (tb[CTA_PROTOINFO_TCP_STATE] &&
1252 nla_get_u8(tb[CTA_PROTOINFO_TCP_STATE]) >= TCP_CONNTRACK_MAX)
1255 spin_lock_bh(&ct->lock);
1256 if (tb[CTA_PROTOINFO_TCP_STATE])
1257 ct->proto.tcp.state = nla_get_u8(tb[CTA_PROTOINFO_TCP_STATE]);
1259 if (tb[CTA_PROTOINFO_TCP_FLAGS_ORIGINAL]) {
1260 struct nf_ct_tcp_flags *attr =
1261 nla_data(tb[CTA_PROTOINFO_TCP_FLAGS_ORIGINAL]);
1262 ct->proto.tcp.seen[0].flags &= ~attr->mask;
1263 ct->proto.tcp.seen[0].flags |= attr->flags & attr->mask;
1266 if (tb[CTA_PROTOINFO_TCP_FLAGS_REPLY]) {
1267 struct nf_ct_tcp_flags *attr =
1268 nla_data(tb[CTA_PROTOINFO_TCP_FLAGS_REPLY]);
1269 ct->proto.tcp.seen[1].flags &= ~attr->mask;
1270 ct->proto.tcp.seen[1].flags |= attr->flags & attr->mask;
1273 if (tb[CTA_PROTOINFO_TCP_WSCALE_ORIGINAL] &&
1274 tb[CTA_PROTOINFO_TCP_WSCALE_REPLY] &&
1275 ct->proto.tcp.seen[0].flags & IP_CT_TCP_FLAG_WINDOW_SCALE &&
1276 ct->proto.tcp.seen[1].flags & IP_CT_TCP_FLAG_WINDOW_SCALE) {
1277 ct->proto.tcp.seen[0].td_scale =
1278 nla_get_u8(tb[CTA_PROTOINFO_TCP_WSCALE_ORIGINAL]);
1279 ct->proto.tcp.seen[1].td_scale =
1280 nla_get_u8(tb[CTA_PROTOINFO_TCP_WSCALE_REPLY]);
1282 spin_unlock_bh(&ct->lock);
1287 static int tcp_nlattr_size(void)
1289 return nla_total_size(0) /* CTA_PROTOINFO_TCP */
1290 + nla_policy_len(tcp_nla_policy, CTA_PROTOINFO_TCP_MAX + 1);
1293 static int tcp_nlattr_tuple_size(void)
1295 return nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1);
1299 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
1301 #include <linux/netfilter/nfnetlink.h>
1302 #include <linux/netfilter/nfnetlink_cttimeout.h>
1304 static int tcp_timeout_nlattr_to_obj(struct nlattr *tb[],
1305 struct net *net, void *data)
1307 unsigned int *timeouts = data;
1308 struct nf_tcp_net *tn = tcp_pernet(net);
1311 /* set default TCP timeouts. */
1312 for (i=0; i<TCP_CONNTRACK_TIMEOUT_MAX; i++)
1313 timeouts[i] = tn->timeouts[i];
1315 if (tb[CTA_TIMEOUT_TCP_SYN_SENT]) {
1316 timeouts[TCP_CONNTRACK_SYN_SENT] =
1317 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_SYN_SENT]))*HZ;
1319 if (tb[CTA_TIMEOUT_TCP_SYN_RECV]) {
1320 timeouts[TCP_CONNTRACK_SYN_RECV] =
1321 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_SYN_RECV]))*HZ;
1323 if (tb[CTA_TIMEOUT_TCP_ESTABLISHED]) {
1324 timeouts[TCP_CONNTRACK_ESTABLISHED] =
1325 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_ESTABLISHED]))*HZ;
1327 if (tb[CTA_TIMEOUT_TCP_FIN_WAIT]) {
1328 timeouts[TCP_CONNTRACK_FIN_WAIT] =
1329 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_FIN_WAIT]))*HZ;
1331 if (tb[CTA_TIMEOUT_TCP_CLOSE_WAIT]) {
1332 timeouts[TCP_CONNTRACK_CLOSE_WAIT] =
1333 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_CLOSE_WAIT]))*HZ;
1335 if (tb[CTA_TIMEOUT_TCP_LAST_ACK]) {
1336 timeouts[TCP_CONNTRACK_LAST_ACK] =
1337 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_LAST_ACK]))*HZ;
1339 if (tb[CTA_TIMEOUT_TCP_TIME_WAIT]) {
1340 timeouts[TCP_CONNTRACK_TIME_WAIT] =
1341 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_TIME_WAIT]))*HZ;
1343 if (tb[CTA_TIMEOUT_TCP_CLOSE]) {
1344 timeouts[TCP_CONNTRACK_CLOSE] =
1345 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_CLOSE]))*HZ;
1347 if (tb[CTA_TIMEOUT_TCP_SYN_SENT2]) {
1348 timeouts[TCP_CONNTRACK_SYN_SENT2] =
1349 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_SYN_SENT2]))*HZ;
1351 if (tb[CTA_TIMEOUT_TCP_RETRANS]) {
1352 timeouts[TCP_CONNTRACK_RETRANS] =
1353 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_RETRANS]))*HZ;
1355 if (tb[CTA_TIMEOUT_TCP_UNACK]) {
1356 timeouts[TCP_CONNTRACK_UNACK] =
1357 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_UNACK]))*HZ;
1363 tcp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
1365 const unsigned int *timeouts = data;
1367 if (nla_put_be32(skb, CTA_TIMEOUT_TCP_SYN_SENT,
1368 htonl(timeouts[TCP_CONNTRACK_SYN_SENT] / HZ)) ||
1369 nla_put_be32(skb, CTA_TIMEOUT_TCP_SYN_RECV,
1370 htonl(timeouts[TCP_CONNTRACK_SYN_RECV] / HZ)) ||
1371 nla_put_be32(skb, CTA_TIMEOUT_TCP_ESTABLISHED,
1372 htonl(timeouts[TCP_CONNTRACK_ESTABLISHED] / HZ)) ||
1373 nla_put_be32(skb, CTA_TIMEOUT_TCP_FIN_WAIT,
1374 htonl(timeouts[TCP_CONNTRACK_FIN_WAIT] / HZ)) ||
1375 nla_put_be32(skb, CTA_TIMEOUT_TCP_CLOSE_WAIT,
1376 htonl(timeouts[TCP_CONNTRACK_CLOSE_WAIT] / HZ)) ||
1377 nla_put_be32(skb, CTA_TIMEOUT_TCP_LAST_ACK,
1378 htonl(timeouts[TCP_CONNTRACK_LAST_ACK] / HZ)) ||
1379 nla_put_be32(skb, CTA_TIMEOUT_TCP_TIME_WAIT,
1380 htonl(timeouts[TCP_CONNTRACK_TIME_WAIT] / HZ)) ||
1381 nla_put_be32(skb, CTA_TIMEOUT_TCP_CLOSE,
1382 htonl(timeouts[TCP_CONNTRACK_CLOSE] / HZ)) ||
1383 nla_put_be32(skb, CTA_TIMEOUT_TCP_SYN_SENT2,
1384 htonl(timeouts[TCP_CONNTRACK_SYN_SENT2] / HZ)) ||
1385 nla_put_be32(skb, CTA_TIMEOUT_TCP_RETRANS,
1386 htonl(timeouts[TCP_CONNTRACK_RETRANS] / HZ)) ||
1387 nla_put_be32(skb, CTA_TIMEOUT_TCP_UNACK,
1388 htonl(timeouts[TCP_CONNTRACK_UNACK] / HZ)))
1389 goto nla_put_failure;
1396 static const struct nla_policy tcp_timeout_nla_policy[CTA_TIMEOUT_TCP_MAX+1] = {
1397 [CTA_TIMEOUT_TCP_SYN_SENT] = { .type = NLA_U32 },
1398 [CTA_TIMEOUT_TCP_SYN_RECV] = { .type = NLA_U32 },
1399 [CTA_TIMEOUT_TCP_ESTABLISHED] = { .type = NLA_U32 },
1400 [CTA_TIMEOUT_TCP_FIN_WAIT] = { .type = NLA_U32 },
1401 [CTA_TIMEOUT_TCP_CLOSE_WAIT] = { .type = NLA_U32 },
1402 [CTA_TIMEOUT_TCP_LAST_ACK] = { .type = NLA_U32 },
1403 [CTA_TIMEOUT_TCP_TIME_WAIT] = { .type = NLA_U32 },
1404 [CTA_TIMEOUT_TCP_CLOSE] = { .type = NLA_U32 },
1405 [CTA_TIMEOUT_TCP_SYN_SENT2] = { .type = NLA_U32 },
1406 [CTA_TIMEOUT_TCP_RETRANS] = { .type = NLA_U32 },
1407 [CTA_TIMEOUT_TCP_UNACK] = { .type = NLA_U32 },
1409 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
1411 #ifdef CONFIG_SYSCTL
1412 static struct ctl_table tcp_sysctl_table[] = {
1414 .procname = "nf_conntrack_tcp_timeout_syn_sent",
1415 .maxlen = sizeof(unsigned int),
1417 .proc_handler = proc_dointvec_jiffies,
1420 .procname = "nf_conntrack_tcp_timeout_syn_recv",
1421 .maxlen = sizeof(unsigned int),
1423 .proc_handler = proc_dointvec_jiffies,
1426 .procname = "nf_conntrack_tcp_timeout_established",
1427 .maxlen = sizeof(unsigned int),
1429 .proc_handler = proc_dointvec_jiffies,
1432 .procname = "nf_conntrack_tcp_timeout_fin_wait",
1433 .maxlen = sizeof(unsigned int),
1435 .proc_handler = proc_dointvec_jiffies,
1438 .procname = "nf_conntrack_tcp_timeout_close_wait",
1439 .maxlen = sizeof(unsigned int),
1441 .proc_handler = proc_dointvec_jiffies,
1444 .procname = "nf_conntrack_tcp_timeout_last_ack",
1445 .maxlen = sizeof(unsigned int),
1447 .proc_handler = proc_dointvec_jiffies,
1450 .procname = "nf_conntrack_tcp_timeout_time_wait",
1451 .maxlen = sizeof(unsigned int),
1453 .proc_handler = proc_dointvec_jiffies,
1456 .procname = "nf_conntrack_tcp_timeout_close",
1457 .maxlen = sizeof(unsigned int),
1459 .proc_handler = proc_dointvec_jiffies,
1462 .procname = "nf_conntrack_tcp_timeout_max_retrans",
1463 .maxlen = sizeof(unsigned int),
1465 .proc_handler = proc_dointvec_jiffies,
1468 .procname = "nf_conntrack_tcp_timeout_unacknowledged",
1469 .maxlen = sizeof(unsigned int),
1471 .proc_handler = proc_dointvec_jiffies,
1474 .procname = "nf_conntrack_tcp_loose",
1475 .maxlen = sizeof(unsigned int),
1477 .proc_handler = proc_dointvec,
1480 .procname = "nf_conntrack_tcp_be_liberal",
1481 .maxlen = sizeof(unsigned int),
1483 .proc_handler = proc_dointvec,
1486 .procname = "nf_conntrack_tcp_max_retrans",
1487 .maxlen = sizeof(unsigned int),
1489 .proc_handler = proc_dointvec,
1493 #endif /* CONFIG_SYSCTL */
1495 static int tcp_kmemdup_sysctl_table(struct nf_proto_net *pn,
1496 struct nf_tcp_net *tn)
1498 #ifdef CONFIG_SYSCTL
1502 pn->ctl_table = kmemdup(tcp_sysctl_table,
1503 sizeof(tcp_sysctl_table),
1508 pn->ctl_table[0].data = &tn->timeouts[TCP_CONNTRACK_SYN_SENT];
1509 pn->ctl_table[1].data = &tn->timeouts[TCP_CONNTRACK_SYN_RECV];
1510 pn->ctl_table[2].data = &tn->timeouts[TCP_CONNTRACK_ESTABLISHED];
1511 pn->ctl_table[3].data = &tn->timeouts[TCP_CONNTRACK_FIN_WAIT];
1512 pn->ctl_table[4].data = &tn->timeouts[TCP_CONNTRACK_CLOSE_WAIT];
1513 pn->ctl_table[5].data = &tn->timeouts[TCP_CONNTRACK_LAST_ACK];
1514 pn->ctl_table[6].data = &tn->timeouts[TCP_CONNTRACK_TIME_WAIT];
1515 pn->ctl_table[7].data = &tn->timeouts[TCP_CONNTRACK_CLOSE];
1516 pn->ctl_table[8].data = &tn->timeouts[TCP_CONNTRACK_RETRANS];
1517 pn->ctl_table[9].data = &tn->timeouts[TCP_CONNTRACK_UNACK];
1518 pn->ctl_table[10].data = &tn->tcp_loose;
1519 pn->ctl_table[11].data = &tn->tcp_be_liberal;
1520 pn->ctl_table[12].data = &tn->tcp_max_retrans;
1525 static int tcp_init_net(struct net *net, u_int16_t proto)
1527 struct nf_tcp_net *tn = tcp_pernet(net);
1528 struct nf_proto_net *pn = &tn->pn;
1533 for (i = 0; i < TCP_CONNTRACK_TIMEOUT_MAX; i++)
1534 tn->timeouts[i] = tcp_timeouts[i];
1536 tn->tcp_loose = nf_ct_tcp_loose;
1537 tn->tcp_be_liberal = nf_ct_tcp_be_liberal;
1538 tn->tcp_max_retrans = nf_ct_tcp_max_retrans;
1541 return tcp_kmemdup_sysctl_table(pn, tn);
1544 static struct nf_proto_net *tcp_get_net_proto(struct net *net)
1546 return &net->ct.nf_ct_proto.tcp.pn;
1549 struct nf_conntrack_l4proto nf_conntrack_l4proto_tcp4 __read_mostly =
1552 .l4proto = IPPROTO_TCP,
1554 .pkt_to_tuple = tcp_pkt_to_tuple,
1555 .invert_tuple = tcp_invert_tuple,
1556 .print_tuple = tcp_print_tuple,
1557 .print_conntrack = tcp_print_conntrack,
1558 .packet = tcp_packet,
1559 .get_timeouts = tcp_get_timeouts,
1562 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
1563 .to_nlattr = tcp_to_nlattr,
1564 .nlattr_size = tcp_nlattr_size,
1565 .from_nlattr = nlattr_to_tcp,
1566 .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
1567 .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
1568 .nlattr_tuple_size = tcp_nlattr_tuple_size,
1569 .nla_policy = nf_ct_port_nla_policy,
1571 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
1573 .nlattr_to_obj = tcp_timeout_nlattr_to_obj,
1574 .obj_to_nlattr = tcp_timeout_obj_to_nlattr,
1575 .nlattr_max = CTA_TIMEOUT_TCP_MAX,
1576 .obj_size = sizeof(unsigned int) *
1577 TCP_CONNTRACK_TIMEOUT_MAX,
1578 .nla_policy = tcp_timeout_nla_policy,
1580 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
1581 .init_net = tcp_init_net,
1582 .get_net_proto = tcp_get_net_proto,
1584 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_tcp4);
1586 struct nf_conntrack_l4proto nf_conntrack_l4proto_tcp6 __read_mostly =
1588 .l3proto = PF_INET6,
1589 .l4proto = IPPROTO_TCP,
1591 .pkt_to_tuple = tcp_pkt_to_tuple,
1592 .invert_tuple = tcp_invert_tuple,
1593 .print_tuple = tcp_print_tuple,
1594 .print_conntrack = tcp_print_conntrack,
1595 .packet = tcp_packet,
1596 .get_timeouts = tcp_get_timeouts,
1599 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
1600 .to_nlattr = tcp_to_nlattr,
1601 .nlattr_size = tcp_nlattr_size,
1602 .from_nlattr = nlattr_to_tcp,
1603 .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
1604 .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
1605 .nlattr_tuple_size = tcp_nlattr_tuple_size,
1606 .nla_policy = nf_ct_port_nla_policy,
1608 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
1610 .nlattr_to_obj = tcp_timeout_nlattr_to_obj,
1611 .obj_to_nlattr = tcp_timeout_obj_to_nlattr,
1612 .nlattr_max = CTA_TIMEOUT_TCP_MAX,
1613 .obj_size = sizeof(unsigned int) *
1614 TCP_CONNTRACK_TIMEOUT_MAX,
1615 .nla_policy = tcp_timeout_nla_policy,
1617 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
1618 .init_net = tcp_init_net,
1619 .get_net_proto = tcp_get_net_proto,
1621 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_tcp6);