1 // SPDX-License-Identifier: GPL-2.0-only
2 /* (C) 1999-2001 Paul `Rusty' Russell
3 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
4 * (C) 2002-2013 Jozsef Kadlecsik <kadlec@netfilter.org>
5 * (C) 2006-2012 Patrick McHardy <kaber@trash.net>
8 #include <linux/types.h>
9 #include <linux/timer.h>
10 #include <linux/module.h>
12 #include <linux/tcp.h>
13 #include <linux/spinlock.h>
14 #include <linux/skbuff.h>
15 #include <linux/ipv6.h>
16 #include <net/ip6_checksum.h>
17 #include <asm/unaligned.h>
21 #include <linux/netfilter.h>
22 #include <linux/netfilter_ipv4.h>
23 #include <linux/netfilter_ipv6.h>
24 #include <net/netfilter/nf_conntrack.h>
25 #include <net/netfilter/nf_conntrack_l4proto.h>
26 #include <net/netfilter/nf_conntrack_ecache.h>
27 #include <net/netfilter/nf_conntrack_seqadj.h>
28 #include <net/netfilter/nf_conntrack_synproxy.h>
29 #include <net/netfilter/nf_conntrack_timeout.h>
30 #include <net/netfilter/nf_log.h>
31 #include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
32 #include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
34 /* "Be conservative in what you do,
35 be liberal in what you accept from others."
36 If it's non-zero, we mark only out of window RST segments as INVALID. */
37 static int nf_ct_tcp_be_liberal __read_mostly = 0;
39 /* If it is set to zero, we disable picking up already established
41 static int nf_ct_tcp_loose __read_mostly = 1;
43 /* Max number of the retransmitted packets without receiving an (acceptable)
44 ACK from the destination. If this number is reached, a shorter timer
46 static int nf_ct_tcp_max_retrans __read_mostly = 3;
48 /* FIXME: Examine ipfilter's timeouts and conntrack transitions more
49 closely. They're more complex. --RR */
51 static const char *const tcp_conntrack_names[] = {
65 #define MINS * 60 SECS
66 #define HOURS * 60 MINS
67 #define DAYS * 24 HOURS
69 static const unsigned int tcp_timeouts[TCP_CONNTRACK_TIMEOUT_MAX] = {
70 [TCP_CONNTRACK_SYN_SENT] = 2 MINS,
71 [TCP_CONNTRACK_SYN_RECV] = 60 SECS,
72 [TCP_CONNTRACK_ESTABLISHED] = 5 DAYS,
73 [TCP_CONNTRACK_FIN_WAIT] = 2 MINS,
74 [TCP_CONNTRACK_CLOSE_WAIT] = 60 SECS,
75 [TCP_CONNTRACK_LAST_ACK] = 30 SECS,
76 [TCP_CONNTRACK_TIME_WAIT] = 2 MINS,
77 [TCP_CONNTRACK_CLOSE] = 10 SECS,
78 [TCP_CONNTRACK_SYN_SENT2] = 2 MINS,
79 /* RFC1122 says the R2 limit should be at least 100 seconds.
80 Linux uses 15 packets as limit, which corresponds
81 to ~13-30min depending on RTO. */
82 [TCP_CONNTRACK_RETRANS] = 5 MINS,
83 [TCP_CONNTRACK_UNACK] = 5 MINS,
86 #define sNO TCP_CONNTRACK_NONE
87 #define sSS TCP_CONNTRACK_SYN_SENT
88 #define sSR TCP_CONNTRACK_SYN_RECV
89 #define sES TCP_CONNTRACK_ESTABLISHED
90 #define sFW TCP_CONNTRACK_FIN_WAIT
91 #define sCW TCP_CONNTRACK_CLOSE_WAIT
92 #define sLA TCP_CONNTRACK_LAST_ACK
93 #define sTW TCP_CONNTRACK_TIME_WAIT
94 #define sCL TCP_CONNTRACK_CLOSE
95 #define sS2 TCP_CONNTRACK_SYN_SENT2
96 #define sIV TCP_CONNTRACK_MAX
97 #define sIG TCP_CONNTRACK_IGNORE
99 /* What TCP flags are set from RST/SYN/FIN/ACK. */
110 * The TCP state transition table needs a few words...
112 * We are the man in the middle. All the packets go through us
113 * but might get lost in transit to the destination.
114 * It is assumed that the destinations can't receive segments
117 * The checked segment is in window, but our windows are *not*
118 * equivalent with the ones of the sender/receiver. We always
119 * try to guess the state of the current sender.
121 * The meaning of the states are:
123 * NONE: initial state
124 * SYN_SENT: SYN-only packet seen
125 * SYN_SENT2: SYN-only packet seen from reply dir, simultaneous open
126 * SYN_RECV: SYN-ACK packet seen
127 * ESTABLISHED: ACK packet seen
128 * FIN_WAIT: FIN packet seen
129 * CLOSE_WAIT: ACK seen (after FIN)
130 * LAST_ACK: FIN seen (after FIN)
131 * TIME_WAIT: last ACK seen
132 * CLOSE: closed connection (RST)
134 * Packets marked as IGNORED (sIG):
135 * if they may be either invalid or valid
136 * and the receiver may send back a connection
137 * closing RST or a SYN/ACK.
139 * Packets marked as INVALID (sIV):
140 * if we regard them as truly invalid packets
142 static const u8 tcp_conntracks[2][6][TCP_CONNTRACK_MAX] = {
145 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
146 /*syn*/ { sSS, sSS, sIG, sIG, sIG, sIG, sIG, sSS, sSS, sS2 },
148 * sNO -> sSS Initialize a new connection
149 * sSS -> sSS Retransmitted SYN
150 * sS2 -> sS2 Late retransmitted SYN
152 * sES -> sIG Error: SYNs in window outside the SYN_SENT state
153 * are errors. Receiver will reply with RST
154 * and close the connection.
155 * Or we are not in sync and hold a dead connection.
159 * sTW -> sSS Reopened connection (RFC 1122).
162 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
163 /*synack*/ { sIV, sIV, sSR, sIV, sIV, sIV, sIV, sIV, sIV, sSR },
165 * sNO -> sIV Too late and no reason to do anything
166 * sSS -> sIV Client can't send SYN and then SYN/ACK
167 * sS2 -> sSR SYN/ACK sent to SYN2 in simultaneous open
168 * sSR -> sSR Late retransmitted SYN/ACK in simultaneous open
169 * sES -> sIV Invalid SYN/ACK packets sent by the client
176 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
177 /*fin*/ { sIV, sIV, sFW, sFW, sLA, sLA, sLA, sTW, sCL, sIV },
179 * sNO -> sIV Too late and no reason to do anything...
180 * sSS -> sIV Client migth not send FIN in this state:
181 * we enforce waiting for a SYN/ACK reply first.
183 * sSR -> sFW Close started.
185 * sFW -> sLA FIN seen in both directions, waiting for
187 * Migth be a retransmitted FIN as well...
189 * sLA -> sLA Retransmitted FIN. Remain in the same state.
193 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
194 /*ack*/ { sES, sIV, sES, sES, sCW, sCW, sTW, sTW, sCL, sIV },
196 * sNO -> sES Assumed.
197 * sSS -> sIV ACK is invalid: we haven't seen a SYN/ACK yet.
199 * sSR -> sES Established state is reached.
201 * sFW -> sCW Normal close request answered by ACK.
203 * sLA -> sTW Last ACK detected (RFC5961 challenged)
204 * sTW -> sTW Retransmitted last ACK. Remain in the same state.
207 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
208 /*rst*/ { sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL },
209 /*none*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV }
213 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
214 /*syn*/ { sIV, sS2, sIV, sIV, sIV, sIV, sIV, sSS, sIV, sS2 },
216 * sNO -> sIV Never reached.
217 * sSS -> sS2 Simultaneous open
218 * sS2 -> sS2 Retransmitted simultaneous SYN
219 * sSR -> sIV Invalid SYN packets sent by the server
224 * sTW -> sSS Reopened connection, but server may have switched role
227 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
228 /*synack*/ { sIV, sSR, sIG, sIG, sIG, sIG, sIG, sIG, sIG, sSR },
230 * sSS -> sSR Standard open.
231 * sS2 -> sSR Simultaneous open
232 * sSR -> sIG Retransmitted SYN/ACK, ignore it.
233 * sES -> sIG Late retransmitted SYN/ACK?
234 * sFW -> sIG Might be SYN/ACK answering ignored SYN
240 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
241 /*fin*/ { sIV, sIV, sFW, sFW, sLA, sLA, sLA, sTW, sCL, sIV },
243 * sSS -> sIV Server might not send FIN in this state.
245 * sSR -> sFW Close started.
247 * sFW -> sLA FIN seen in both directions.
249 * sLA -> sLA Retransmitted FIN.
253 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
254 /*ack*/ { sIV, sIG, sSR, sES, sCW, sCW, sTW, sTW, sCL, sIG },
256 * sSS -> sIG Might be a half-open connection.
258 * sSR -> sSR Might answer late resent SYN.
260 * sFW -> sCW Normal close request answered by ACK.
262 * sLA -> sTW Last ACK detected (RFC5961 challenged)
263 * sTW -> sTW Retransmitted last ACK.
266 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
267 /*rst*/ { sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL },
268 /*none*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV }
272 #ifdef CONFIG_NF_CONNTRACK_PROCFS
273 /* Print out the private part of the conntrack. */
274 static void tcp_print_conntrack(struct seq_file *s, struct nf_conn *ct)
276 if (test_bit(IPS_OFFLOAD_BIT, &ct->status))
279 seq_printf(s, "%s ", tcp_conntrack_names[ct->proto.tcp.state]);
283 static unsigned int get_conntrack_index(const struct tcphdr *tcph)
285 if (tcph->rst) return TCP_RST_SET;
286 else if (tcph->syn) return (tcph->ack ? TCP_SYNACK_SET : TCP_SYN_SET);
287 else if (tcph->fin) return TCP_FIN_SET;
288 else if (tcph->ack) return TCP_ACK_SET;
289 else return TCP_NONE_SET;
292 /* TCP connection tracking based on 'Real Stateful TCP Packet Filtering
293 in IP Filter' by Guido van Rooij.
295 http://www.sane.nl/events/sane2000/papers.html
296 http://www.darkart.com/mirrors/www.obfuscation.org/ipf/
298 The boundaries and the conditions are changed according to RFC793:
299 the packet must intersect the window (i.e. segments may be
300 after the right or before the left edge) and thus receivers may ACK
301 segments after the right edge of the window.
303 td_maxend = max(sack + max(win,1)) seen in reply packets
304 td_maxwin = max(max(win, 1)) + (sack - ack) seen in sent packets
305 td_maxwin += seq + len - sender.td_maxend
306 if seq + len > sender.td_maxend
307 td_end = max(seq + len) seen in sent packets
309 I. Upper bound for valid data: seq <= sender.td_maxend
310 II. Lower bound for valid data: seq + len >= sender.td_end - receiver.td_maxwin
311 III. Upper bound for valid (s)ack: sack <= receiver.td_end
312 IV. Lower bound for valid (s)ack: sack >= receiver.td_end - MAXACKWINDOW
314 where sack is the highest right edge of sack block found in the packet
315 or ack in the case of packet without SACK option.
317 The upper bound limit for a valid (s)ack is not ignored -
318 we doesn't have to deal with fragments.
321 static inline __u32 segment_seq_plus_len(__u32 seq,
323 unsigned int dataoff,
324 const struct tcphdr *tcph)
326 /* XXX Should I use payload length field in IP/IPv6 header ?
328 return (seq + len - dataoff - tcph->doff*4
329 + (tcph->syn ? 1 : 0) + (tcph->fin ? 1 : 0));
332 /* Fixme: what about big packets? */
333 #define MAXACKWINCONST 66000
334 #define MAXACKWINDOW(sender) \
335 ((sender)->td_maxwin > MAXACKWINCONST ? (sender)->td_maxwin \
339 * Simplified tcp_parse_options routine from tcp_input.c
341 static void tcp_options(const struct sk_buff *skb,
342 unsigned int dataoff,
343 const struct tcphdr *tcph,
344 struct ip_ct_tcp_state *state)
346 unsigned char buff[(15 * 4) - sizeof(struct tcphdr)];
347 const unsigned char *ptr;
348 int length = (tcph->doff*4) - sizeof(struct tcphdr);
353 ptr = skb_header_pointer(skb, dataoff + sizeof(struct tcphdr),
367 case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */
374 if (opsize < 2) /* "silly options" */
377 return; /* don't parse partial options */
379 if (opcode == TCPOPT_SACK_PERM
380 && opsize == TCPOLEN_SACK_PERM)
381 state->flags |= IP_CT_TCP_FLAG_SACK_PERM;
382 else if (opcode == TCPOPT_WINDOW
383 && opsize == TCPOLEN_WINDOW) {
384 state->td_scale = *(u_int8_t *)ptr;
386 if (state->td_scale > TCP_MAX_WSCALE)
387 state->td_scale = TCP_MAX_WSCALE;
390 IP_CT_TCP_FLAG_WINDOW_SCALE;
398 static void tcp_sack(const struct sk_buff *skb, unsigned int dataoff,
399 const struct tcphdr *tcph, __u32 *sack)
401 unsigned char buff[(15 * 4) - sizeof(struct tcphdr)];
402 const unsigned char *ptr;
403 int length = (tcph->doff*4) - sizeof(struct tcphdr);
409 ptr = skb_header_pointer(skb, dataoff + sizeof(struct tcphdr),
413 /* Fast path for timestamp-only option */
414 if (length == TCPOLEN_TSTAMP_ALIGNED
415 && *(__be32 *)ptr == htonl((TCPOPT_NOP << 24)
417 | (TCPOPT_TIMESTAMP << 8)
418 | TCPOLEN_TIMESTAMP))
428 case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */
435 if (opsize < 2) /* "silly options" */
438 return; /* don't parse partial options */
440 if (opcode == TCPOPT_SACK
441 && opsize >= (TCPOLEN_SACK_BASE
442 + TCPOLEN_SACK_PERBLOCK)
443 && !((opsize - TCPOLEN_SACK_BASE)
444 % TCPOLEN_SACK_PERBLOCK)) {
446 i < (opsize - TCPOLEN_SACK_BASE);
447 i += TCPOLEN_SACK_PERBLOCK) {
448 tmp = get_unaligned_be32((__be32 *)(ptr+i)+1);
450 if (after(tmp, *sack))
461 static bool tcp_in_window(const struct nf_conn *ct,
462 struct ip_ct_tcp *state,
463 enum ip_conntrack_dir dir,
465 const struct sk_buff *skb,
466 unsigned int dataoff,
467 const struct tcphdr *tcph)
469 struct net *net = nf_ct_net(ct);
470 struct nf_tcp_net *tn = nf_tcp_pernet(net);
471 struct ip_ct_tcp_state *sender = &state->seen[dir];
472 struct ip_ct_tcp_state *receiver = &state->seen[!dir];
473 const struct nf_conntrack_tuple *tuple = &ct->tuplehash[dir].tuple;
474 __u32 seq, ack, sack, end, win, swin;
477 bool res, in_recv_win;
480 * Get the required data from the packet.
482 seq = ntohl(tcph->seq);
483 ack = sack = ntohl(tcph->ack_seq);
484 win_raw = ntohs(tcph->window);
486 end = segment_seq_plus_len(seq, skb->len, dataoff, tcph);
488 if (receiver->flags & IP_CT_TCP_FLAG_SACK_PERM)
489 tcp_sack(skb, dataoff, tcph, &sack);
491 /* Take into account NAT sequence number mangling */
492 receiver_offset = nf_ct_seq_offset(ct, !dir, ack - 1);
493 ack -= receiver_offset;
494 sack -= receiver_offset;
496 pr_debug("tcp_in_window: START\n");
497 pr_debug("tcp_in_window: ");
498 nf_ct_dump_tuple(tuple);
499 pr_debug("seq=%u ack=%u+(%d) sack=%u+(%d) win=%u end=%u\n",
500 seq, ack, receiver_offset, sack, receiver_offset, win, end);
501 pr_debug("tcp_in_window: sender end=%u maxend=%u maxwin=%u scale=%i "
502 "receiver end=%u maxend=%u maxwin=%u scale=%i\n",
503 sender->td_end, sender->td_maxend, sender->td_maxwin,
505 receiver->td_end, receiver->td_maxend, receiver->td_maxwin,
508 if (sender->td_maxwin == 0) {
510 * Initialize sender data.
514 * SYN-ACK in reply to a SYN
515 * or SYN from reply direction in simultaneous open.
518 sender->td_maxend = end;
519 sender->td_maxwin = (win == 0 ? 1 : win);
521 tcp_options(skb, dataoff, tcph, sender);
524 * Both sides must send the Window Scale option
525 * to enable window scaling in either direction.
527 if (!(sender->flags & IP_CT_TCP_FLAG_WINDOW_SCALE
528 && receiver->flags & IP_CT_TCP_FLAG_WINDOW_SCALE))
530 receiver->td_scale = 0;
532 /* Simultaneous open */
536 * We are in the middle of a connection,
537 * its history is lost for us.
538 * Let's try to use the data from the packet.
540 sender->td_end = end;
541 swin = win << sender->td_scale;
542 sender->td_maxwin = (swin == 0 ? 1 : swin);
543 sender->td_maxend = end + sender->td_maxwin;
544 if (receiver->td_maxwin == 0) {
545 /* We haven't seen traffic in the other
546 * direction yet but we have to tweak window
547 * tracking to pass III and IV until that
550 receiver->td_end = receiver->td_maxend = sack;
551 } else if (sack == receiver->td_end + 1) {
552 /* Likely a reply to a keepalive.
559 } else if (((state->state == TCP_CONNTRACK_SYN_SENT
560 && dir == IP_CT_DIR_ORIGINAL)
561 || (state->state == TCP_CONNTRACK_SYN_RECV
562 && dir == IP_CT_DIR_REPLY))
563 && after(end, sender->td_end)) {
565 * RFC 793: "if a TCP is reinitialized ... then it need
566 * not wait at all; it must only be sure to use sequence
567 * numbers larger than those recently used."
570 sender->td_maxend = end;
571 sender->td_maxwin = (win == 0 ? 1 : win);
573 tcp_options(skb, dataoff, tcph, sender);
578 * If there is no ACK, just pretend it was set and OK.
580 ack = sack = receiver->td_end;
581 } else if (((tcp_flag_word(tcph) & (TCP_FLAG_ACK|TCP_FLAG_RST)) ==
582 (TCP_FLAG_ACK|TCP_FLAG_RST))
585 * Broken TCP stacks, that set ACK in RST packets as well
586 * with zero ack value.
588 ack = sack = receiver->td_end;
591 if (tcph->rst && seq == 0 && state->state == TCP_CONNTRACK_SYN_SENT)
593 * RST sent answering SYN.
595 seq = end = sender->td_end;
597 pr_debug("tcp_in_window: ");
598 nf_ct_dump_tuple(tuple);
599 pr_debug("seq=%u ack=%u+(%d) sack=%u+(%d) win=%u end=%u\n",
600 seq, ack, receiver_offset, sack, receiver_offset, win, end);
601 pr_debug("tcp_in_window: sender end=%u maxend=%u maxwin=%u scale=%i "
602 "receiver end=%u maxend=%u maxwin=%u scale=%i\n",
603 sender->td_end, sender->td_maxend, sender->td_maxwin,
605 receiver->td_end, receiver->td_maxend, receiver->td_maxwin,
608 /* Is the ending sequence in the receive window (if available)? */
609 in_recv_win = !receiver->td_maxwin ||
610 after(end, sender->td_end - receiver->td_maxwin - 1);
612 pr_debug("tcp_in_window: I=%i II=%i III=%i IV=%i\n",
613 before(seq, sender->td_maxend + 1),
614 (in_recv_win ? 1 : 0),
615 before(sack, receiver->td_end + 1),
616 after(sack, receiver->td_end - MAXACKWINDOW(sender) - 1));
618 if (before(seq, sender->td_maxend + 1) &&
620 before(sack, receiver->td_end + 1) &&
621 after(sack, receiver->td_end - MAXACKWINDOW(sender) - 1)) {
623 * Take into account window scaling (RFC 1323).
626 win <<= sender->td_scale;
629 * Update sender data.
631 swin = win + (sack - ack);
632 if (sender->td_maxwin < swin)
633 sender->td_maxwin = swin;
634 if (after(end, sender->td_end)) {
635 sender->td_end = end;
636 sender->flags |= IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED;
639 if (!(sender->flags & IP_CT_TCP_FLAG_MAXACK_SET)) {
640 sender->td_maxack = ack;
641 sender->flags |= IP_CT_TCP_FLAG_MAXACK_SET;
642 } else if (after(ack, sender->td_maxack))
643 sender->td_maxack = ack;
647 * Update receiver data.
649 if (receiver->td_maxwin != 0 && after(end, sender->td_maxend))
650 receiver->td_maxwin += end - sender->td_maxend;
651 if (after(sack + win, receiver->td_maxend - 1)) {
652 receiver->td_maxend = sack + win;
654 receiver->td_maxend++;
656 if (ack == receiver->td_end)
657 receiver->flags &= ~IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED;
660 * Check retransmissions.
662 if (index == TCP_ACK_SET) {
663 if (state->last_dir == dir
664 && state->last_seq == seq
665 && state->last_ack == ack
666 && state->last_end == end
667 && state->last_win == win_raw)
670 state->last_dir = dir;
671 state->last_seq = seq;
672 state->last_ack = ack;
673 state->last_end = end;
674 state->last_win = win_raw;
681 if (sender->flags & IP_CT_TCP_FLAG_BE_LIBERAL ||
685 nf_ct_l4proto_log_invalid(skb, ct,
687 before(seq, sender->td_maxend + 1) ?
689 before(sack, receiver->td_end + 1) ?
690 after(sack, receiver->td_end - MAXACKWINDOW(sender) - 1) ? "BUG"
691 : "ACK is under the lower bound (possible overly delayed ACK)"
692 : "ACK is over the upper bound (ACKed data not seen yet)"
693 : "SEQ is under the lower bound (already ACKed data retransmitted)"
694 : "SEQ is over the upper bound (over the window of the receiver)");
698 pr_debug("tcp_in_window: res=%u sender end=%u maxend=%u maxwin=%u "
699 "receiver end=%u maxend=%u maxwin=%u\n",
700 res, sender->td_end, sender->td_maxend, sender->td_maxwin,
701 receiver->td_end, receiver->td_maxend, receiver->td_maxwin);
706 /* table of valid flag combinations - PUSH, ECE and CWR are always valid */
707 static const u8 tcp_valid_flags[(TCPHDR_FIN|TCPHDR_SYN|TCPHDR_RST|TCPHDR_ACK|
711 [TCPHDR_SYN|TCPHDR_URG] = 1,
712 [TCPHDR_SYN|TCPHDR_ACK] = 1,
714 [TCPHDR_RST|TCPHDR_ACK] = 1,
715 [TCPHDR_FIN|TCPHDR_ACK] = 1,
716 [TCPHDR_FIN|TCPHDR_ACK|TCPHDR_URG] = 1,
718 [TCPHDR_ACK|TCPHDR_URG] = 1,
721 static void tcp_error_log(const struct sk_buff *skb,
722 const struct nf_hook_state *state,
725 nf_l4proto_log_invalid(skb, state->net, state->pf, IPPROTO_TCP, "%s", msg);
728 /* Protect conntrack agaist broken packets. Code taken from ipt_unclean.c. */
729 static bool tcp_error(const struct tcphdr *th,
731 unsigned int dataoff,
732 const struct nf_hook_state *state)
734 unsigned int tcplen = skb->len - dataoff;
737 /* Not whole TCP header or malformed packet */
738 if (th->doff*4 < sizeof(struct tcphdr) || tcplen < th->doff*4) {
739 tcp_error_log(skb, state, "truncated packet");
743 /* Checksum invalid? Ignore.
744 * We skip checking packets on the outgoing path
745 * because the checksum is assumed to be correct.
747 /* FIXME: Source route IP option packets --RR */
748 if (state->net->ct.sysctl_checksum &&
749 state->hook == NF_INET_PRE_ROUTING &&
750 nf_checksum(skb, state->hook, dataoff, IPPROTO_TCP, state->pf)) {
751 tcp_error_log(skb, state, "bad checksum");
755 /* Check TCP flags. */
756 tcpflags = (tcp_flag_byte(th) & ~(TCPHDR_ECE|TCPHDR_CWR|TCPHDR_PSH));
757 if (!tcp_valid_flags[tcpflags]) {
758 tcp_error_log(skb, state, "invalid tcp flag combination");
765 static noinline bool tcp_new(struct nf_conn *ct, const struct sk_buff *skb,
766 unsigned int dataoff,
767 const struct tcphdr *th)
769 enum tcp_conntrack new_state;
770 struct net *net = nf_ct_net(ct);
771 const struct nf_tcp_net *tn = nf_tcp_pernet(net);
772 const struct ip_ct_tcp_state *sender = &ct->proto.tcp.seen[0];
773 const struct ip_ct_tcp_state *receiver = &ct->proto.tcp.seen[1];
775 /* Don't need lock here: this conntrack not in circulation yet */
776 new_state = tcp_conntracks[0][get_conntrack_index(th)][TCP_CONNTRACK_NONE];
778 /* Invalid: delete conntrack */
779 if (new_state >= TCP_CONNTRACK_MAX) {
780 pr_debug("nf_ct_tcp: invalid new deleting.\n");
784 if (new_state == TCP_CONNTRACK_SYN_SENT) {
785 memset(&ct->proto.tcp, 0, sizeof(ct->proto.tcp));
787 ct->proto.tcp.seen[0].td_end =
788 segment_seq_plus_len(ntohl(th->seq), skb->len,
790 ct->proto.tcp.seen[0].td_maxwin = ntohs(th->window);
791 if (ct->proto.tcp.seen[0].td_maxwin == 0)
792 ct->proto.tcp.seen[0].td_maxwin = 1;
793 ct->proto.tcp.seen[0].td_maxend =
794 ct->proto.tcp.seen[0].td_end;
796 tcp_options(skb, dataoff, th, &ct->proto.tcp.seen[0]);
797 } else if (tn->tcp_loose == 0) {
798 /* Don't try to pick up connections. */
801 memset(&ct->proto.tcp, 0, sizeof(ct->proto.tcp));
803 * We are in the middle of a connection,
804 * its history is lost for us.
805 * Let's try to use the data from the packet.
807 ct->proto.tcp.seen[0].td_end =
808 segment_seq_plus_len(ntohl(th->seq), skb->len,
810 ct->proto.tcp.seen[0].td_maxwin = ntohs(th->window);
811 if (ct->proto.tcp.seen[0].td_maxwin == 0)
812 ct->proto.tcp.seen[0].td_maxwin = 1;
813 ct->proto.tcp.seen[0].td_maxend =
814 ct->proto.tcp.seen[0].td_end +
815 ct->proto.tcp.seen[0].td_maxwin;
817 /* We assume SACK and liberal window checking to handle
819 ct->proto.tcp.seen[0].flags =
820 ct->proto.tcp.seen[1].flags = IP_CT_TCP_FLAG_SACK_PERM |
821 IP_CT_TCP_FLAG_BE_LIBERAL;
824 /* tcp_packet will set them */
825 ct->proto.tcp.last_index = TCP_NONE_SET;
827 pr_debug("%s: sender end=%u maxend=%u maxwin=%u scale=%i "
828 "receiver end=%u maxend=%u maxwin=%u scale=%i\n",
830 sender->td_end, sender->td_maxend, sender->td_maxwin,
832 receiver->td_end, receiver->td_maxend, receiver->td_maxwin,
837 static bool nf_conntrack_tcp_established(const struct nf_conn *ct)
839 return ct->proto.tcp.state == TCP_CONNTRACK_ESTABLISHED &&
840 test_bit(IPS_ASSURED_BIT, &ct->status);
843 /* Returns verdict for packet, or -1 for invalid. */
844 int nf_conntrack_tcp_packet(struct nf_conn *ct,
846 unsigned int dataoff,
847 enum ip_conntrack_info ctinfo,
848 const struct nf_hook_state *state)
850 struct net *net = nf_ct_net(ct);
851 struct nf_tcp_net *tn = nf_tcp_pernet(net);
852 struct nf_conntrack_tuple *tuple;
853 enum tcp_conntrack new_state, old_state;
854 unsigned int index, *timeouts;
855 enum ip_conntrack_dir dir;
856 const struct tcphdr *th;
858 unsigned long timeout;
860 th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph);
864 if (tcp_error(th, skb, dataoff, state))
867 if (!nf_ct_is_confirmed(ct) && !tcp_new(ct, skb, dataoff, th))
870 spin_lock_bh(&ct->lock);
871 old_state = ct->proto.tcp.state;
872 dir = CTINFO2DIR(ctinfo);
873 index = get_conntrack_index(th);
874 new_state = tcp_conntracks[dir][index][old_state];
875 tuple = &ct->tuplehash[dir].tuple;
878 case TCP_CONNTRACK_SYN_SENT:
879 if (old_state < TCP_CONNTRACK_TIME_WAIT)
881 /* RFC 1122: "When a connection is closed actively,
882 * it MUST linger in TIME-WAIT state for a time 2xMSL
883 * (Maximum Segment Lifetime). However, it MAY accept
884 * a new SYN from the remote TCP to reopen the connection
885 * directly from TIME-WAIT state, if..."
886 * We ignore the conditions because we are in the
887 * TIME-WAIT state anyway.
889 * Handle aborted connections: we and the server
890 * think there is an existing connection but the client
891 * aborts it and starts a new one.
893 if (((ct->proto.tcp.seen[dir].flags
894 | ct->proto.tcp.seen[!dir].flags)
895 & IP_CT_TCP_FLAG_CLOSE_INIT)
896 || (ct->proto.tcp.last_dir == dir
897 && ct->proto.tcp.last_index == TCP_RST_SET)) {
898 /* Attempt to reopen a closed/aborted connection.
899 * Delete this connection and look up again. */
900 spin_unlock_bh(&ct->lock);
902 /* Only repeat if we can actually remove the timer.
903 * Destruction may already be in progress in process
904 * context and we must give it a chance to terminate.
911 case TCP_CONNTRACK_IGNORE:
914 * Our connection entry may be out of sync, so ignore
915 * packets which may signal the real connection between
916 * the client and the server.
919 * b) SYN/ACK in REPLY
920 * c) ACK in reply direction after initial SYN in original.
922 * If the ignored packet is invalid, the receiver will send
923 * a RST we'll catch below.
925 if (index == TCP_SYNACK_SET
926 && ct->proto.tcp.last_index == TCP_SYN_SET
927 && ct->proto.tcp.last_dir != dir
928 && ntohl(th->ack_seq) == ct->proto.tcp.last_end) {
929 /* b) This SYN/ACK acknowledges a SYN that we earlier
930 * ignored as invalid. This means that the client and
931 * the server are both in sync, while the firewall is
932 * not. We get in sync from the previously annotated
935 old_state = TCP_CONNTRACK_SYN_SENT;
936 new_state = TCP_CONNTRACK_SYN_RECV;
937 ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_end =
938 ct->proto.tcp.last_end;
939 ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_maxend =
940 ct->proto.tcp.last_end;
941 ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_maxwin =
942 ct->proto.tcp.last_win == 0 ?
943 1 : ct->proto.tcp.last_win;
944 ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_scale =
945 ct->proto.tcp.last_wscale;
946 ct->proto.tcp.last_flags &= ~IP_CT_EXP_CHALLENGE_ACK;
947 ct->proto.tcp.seen[ct->proto.tcp.last_dir].flags =
948 ct->proto.tcp.last_flags;
949 memset(&ct->proto.tcp.seen[dir], 0,
950 sizeof(struct ip_ct_tcp_state));
953 ct->proto.tcp.last_index = index;
954 ct->proto.tcp.last_dir = dir;
955 ct->proto.tcp.last_seq = ntohl(th->seq);
956 ct->proto.tcp.last_end =
957 segment_seq_plus_len(ntohl(th->seq), skb->len, dataoff, th);
958 ct->proto.tcp.last_win = ntohs(th->window);
960 /* a) This is a SYN in ORIGINAL. The client and the server
961 * may be in sync but we are not. In that case, we annotate
962 * the TCP options and let the packet go through. If it is a
963 * valid SYN packet, the server will reply with a SYN/ACK, and
964 * then we'll get in sync. Otherwise, the server potentially
965 * responds with a challenge ACK if implementing RFC5961.
967 if (index == TCP_SYN_SET && dir == IP_CT_DIR_ORIGINAL) {
968 struct ip_ct_tcp_state seen = {};
970 ct->proto.tcp.last_flags =
971 ct->proto.tcp.last_wscale = 0;
972 tcp_options(skb, dataoff, th, &seen);
973 if (seen.flags & IP_CT_TCP_FLAG_WINDOW_SCALE) {
974 ct->proto.tcp.last_flags |=
975 IP_CT_TCP_FLAG_WINDOW_SCALE;
976 ct->proto.tcp.last_wscale = seen.td_scale;
978 if (seen.flags & IP_CT_TCP_FLAG_SACK_PERM) {
979 ct->proto.tcp.last_flags |=
980 IP_CT_TCP_FLAG_SACK_PERM;
982 /* Mark the potential for RFC5961 challenge ACK,
983 * this pose a special problem for LAST_ACK state
984 * as ACK is intrepretated as ACKing last FIN.
986 if (old_state == TCP_CONNTRACK_LAST_ACK)
987 ct->proto.tcp.last_flags |=
988 IP_CT_EXP_CHALLENGE_ACK;
990 spin_unlock_bh(&ct->lock);
991 nf_ct_l4proto_log_invalid(skb, ct, "invalid packet ignored in "
992 "state %s ", tcp_conntrack_names[old_state]);
994 case TCP_CONNTRACK_MAX:
995 /* Special case for SYN proxy: when the SYN to the server or
996 * the SYN/ACK from the server is lost, the client may transmit
997 * a keep-alive packet while in SYN_SENT state. This needs to
998 * be associated with the original conntrack entry in order to
999 * generate a new SYN with the correct sequence number.
1001 if (nfct_synproxy(ct) && old_state == TCP_CONNTRACK_SYN_SENT &&
1002 index == TCP_ACK_SET && dir == IP_CT_DIR_ORIGINAL &&
1003 ct->proto.tcp.last_dir == IP_CT_DIR_ORIGINAL &&
1004 ct->proto.tcp.seen[dir].td_end - 1 == ntohl(th->seq)) {
1005 pr_debug("nf_ct_tcp: SYN proxy client keep alive\n");
1006 spin_unlock_bh(&ct->lock);
1010 /* Invalid packet */
1011 pr_debug("nf_ct_tcp: Invalid dir=%i index=%u ostate=%u\n",
1012 dir, get_conntrack_index(th), old_state);
1013 spin_unlock_bh(&ct->lock);
1014 nf_ct_l4proto_log_invalid(skb, ct, "invalid state");
1016 case TCP_CONNTRACK_TIME_WAIT:
1017 /* RFC5961 compliance cause stack to send "challenge-ACK"
1018 * e.g. in response to spurious SYNs. Conntrack MUST
1019 * not believe this ACK is acking last FIN.
1021 if (old_state == TCP_CONNTRACK_LAST_ACK &&
1022 index == TCP_ACK_SET &&
1023 ct->proto.tcp.last_dir != dir &&
1024 ct->proto.tcp.last_index == TCP_SYN_SET &&
1025 (ct->proto.tcp.last_flags & IP_CT_EXP_CHALLENGE_ACK)) {
1026 /* Detected RFC5961 challenge ACK */
1027 ct->proto.tcp.last_flags &= ~IP_CT_EXP_CHALLENGE_ACK;
1028 spin_unlock_bh(&ct->lock);
1029 nf_ct_l4proto_log_invalid(skb, ct, "challenge-ack ignored");
1030 return NF_ACCEPT; /* Don't change state */
1033 case TCP_CONNTRACK_SYN_SENT2:
1034 /* tcp_conntracks table is not smart enough to handle
1035 * simultaneous open.
1037 ct->proto.tcp.last_flags |= IP_CT_TCP_SIMULTANEOUS_OPEN;
1039 case TCP_CONNTRACK_SYN_RECV:
1040 if (dir == IP_CT_DIR_REPLY && index == TCP_ACK_SET &&
1041 ct->proto.tcp.last_flags & IP_CT_TCP_SIMULTANEOUS_OPEN)
1042 new_state = TCP_CONNTRACK_ESTABLISHED;
1044 case TCP_CONNTRACK_CLOSE:
1045 if (index != TCP_RST_SET)
1048 if (ct->proto.tcp.seen[!dir].flags & IP_CT_TCP_FLAG_MAXACK_SET) {
1049 u32 seq = ntohl(th->seq);
1051 if (before(seq, ct->proto.tcp.seen[!dir].td_maxack)) {
1053 spin_unlock_bh(&ct->lock);
1054 nf_ct_l4proto_log_invalid(skb, ct, "invalid rst");
1058 if (!nf_conntrack_tcp_established(ct) ||
1059 seq == ct->proto.tcp.seen[!dir].td_maxack)
1062 /* Check if rst is part of train, such as
1063 * foo:80 > bar:4379: P, 235946583:235946602(19) ack 42
1064 * foo:80 > bar:4379: R, 235946602:235946602(0) ack 42
1066 if (ct->proto.tcp.last_index == TCP_ACK_SET &&
1067 ct->proto.tcp.last_dir == dir &&
1068 seq == ct->proto.tcp.last_end)
1071 /* ... RST sequence number doesn't match exactly, keep
1072 * established state to allow a possible challenge ACK.
1074 new_state = old_state;
1076 if (((test_bit(IPS_SEEN_REPLY_BIT, &ct->status)
1077 && ct->proto.tcp.last_index == TCP_SYN_SET)
1078 || (!test_bit(IPS_ASSURED_BIT, &ct->status)
1079 && ct->proto.tcp.last_index == TCP_ACK_SET))
1080 && ntohl(th->ack_seq) == ct->proto.tcp.last_end) {
1081 /* RST sent to invalid SYN or ACK we had let through
1082 * at a) and c) above:
1084 * a) SYN was in window then
1085 * c) we hold a half-open connection.
1087 * Delete our connection entry.
1088 * We skip window checking, because packet might ACK
1089 * segments we ignored. */
1094 /* Keep compilers happy. */
1098 if (!tcp_in_window(ct, &ct->proto.tcp, dir, index,
1099 skb, dataoff, th)) {
1100 spin_unlock_bh(&ct->lock);
1104 /* From now on we have got in-window packets */
1105 ct->proto.tcp.last_index = index;
1106 ct->proto.tcp.last_dir = dir;
1108 pr_debug("tcp_conntracks: ");
1109 nf_ct_dump_tuple(tuple);
1110 pr_debug("syn=%i ack=%i fin=%i rst=%i old=%i new=%i\n",
1111 (th->syn ? 1 : 0), (th->ack ? 1 : 0),
1112 (th->fin ? 1 : 0), (th->rst ? 1 : 0),
1113 old_state, new_state);
1115 ct->proto.tcp.state = new_state;
1116 if (old_state != new_state
1117 && new_state == TCP_CONNTRACK_FIN_WAIT)
1118 ct->proto.tcp.seen[dir].flags |= IP_CT_TCP_FLAG_CLOSE_INIT;
1120 timeouts = nf_ct_timeout_lookup(ct);
1122 timeouts = tn->timeouts;
1124 if (ct->proto.tcp.retrans >= tn->tcp_max_retrans &&
1125 timeouts[new_state] > timeouts[TCP_CONNTRACK_RETRANS])
1126 timeout = timeouts[TCP_CONNTRACK_RETRANS];
1127 else if (unlikely(index == TCP_RST_SET))
1128 timeout = timeouts[TCP_CONNTRACK_CLOSE];
1129 else if ((ct->proto.tcp.seen[0].flags | ct->proto.tcp.seen[1].flags) &
1130 IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED &&
1131 timeouts[new_state] > timeouts[TCP_CONNTRACK_UNACK])
1132 timeout = timeouts[TCP_CONNTRACK_UNACK];
1133 else if (ct->proto.tcp.last_win == 0 &&
1134 timeouts[new_state] > timeouts[TCP_CONNTRACK_RETRANS])
1135 timeout = timeouts[TCP_CONNTRACK_RETRANS];
1137 timeout = timeouts[new_state];
1138 spin_unlock_bh(&ct->lock);
1140 if (new_state != old_state)
1141 nf_conntrack_event_cache(IPCT_PROTOINFO, ct);
1143 if (!test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
1144 /* If only reply is a RST, we can consider ourselves not to
1145 have an established connection: this is a fairly common
1146 problem case, so we can delete the conntrack
1147 immediately. --RR */
1149 nf_ct_kill_acct(ct, ctinfo, skb);
1152 /* ESTABLISHED without SEEN_REPLY, i.e. mid-connection
1153 * pickup with loose=1. Avoid large ESTABLISHED timeout.
1155 if (new_state == TCP_CONNTRACK_ESTABLISHED &&
1156 timeout > timeouts[TCP_CONNTRACK_UNACK])
1157 timeout = timeouts[TCP_CONNTRACK_UNACK];
1158 } else if (!test_bit(IPS_ASSURED_BIT, &ct->status)
1159 && (old_state == TCP_CONNTRACK_SYN_RECV
1160 || old_state == TCP_CONNTRACK_ESTABLISHED)
1161 && new_state == TCP_CONNTRACK_ESTABLISHED) {
1162 /* Set ASSURED if we see valid ack in ESTABLISHED
1163 after SYN_RECV or a valid answer for a picked up
1165 set_bit(IPS_ASSURED_BIT, &ct->status);
1166 nf_conntrack_event_cache(IPCT_ASSURED, ct);
1168 nf_ct_refresh_acct(ct, ctinfo, skb, timeout);
1173 static bool tcp_can_early_drop(const struct nf_conn *ct)
1175 switch (ct->proto.tcp.state) {
1176 case TCP_CONNTRACK_FIN_WAIT:
1177 case TCP_CONNTRACK_LAST_ACK:
1178 case TCP_CONNTRACK_TIME_WAIT:
1179 case TCP_CONNTRACK_CLOSE:
1180 case TCP_CONNTRACK_CLOSE_WAIT:
1189 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
1191 #include <linux/netfilter/nfnetlink.h>
1192 #include <linux/netfilter/nfnetlink_conntrack.h>
1194 static int tcp_to_nlattr(struct sk_buff *skb, struct nlattr *nla,
1197 struct nlattr *nest_parms;
1198 struct nf_ct_tcp_flags tmp = {};
1200 spin_lock_bh(&ct->lock);
1201 nest_parms = nla_nest_start(skb, CTA_PROTOINFO_TCP);
1203 goto nla_put_failure;
1205 if (nla_put_u8(skb, CTA_PROTOINFO_TCP_STATE, ct->proto.tcp.state) ||
1206 nla_put_u8(skb, CTA_PROTOINFO_TCP_WSCALE_ORIGINAL,
1207 ct->proto.tcp.seen[0].td_scale) ||
1208 nla_put_u8(skb, CTA_PROTOINFO_TCP_WSCALE_REPLY,
1209 ct->proto.tcp.seen[1].td_scale))
1210 goto nla_put_failure;
1212 tmp.flags = ct->proto.tcp.seen[0].flags;
1213 if (nla_put(skb, CTA_PROTOINFO_TCP_FLAGS_ORIGINAL,
1214 sizeof(struct nf_ct_tcp_flags), &tmp))
1215 goto nla_put_failure;
1217 tmp.flags = ct->proto.tcp.seen[1].flags;
1218 if (nla_put(skb, CTA_PROTOINFO_TCP_FLAGS_REPLY,
1219 sizeof(struct nf_ct_tcp_flags), &tmp))
1220 goto nla_put_failure;
1221 spin_unlock_bh(&ct->lock);
1223 nla_nest_end(skb, nest_parms);
1228 spin_unlock_bh(&ct->lock);
1232 static const struct nla_policy tcp_nla_policy[CTA_PROTOINFO_TCP_MAX+1] = {
1233 [CTA_PROTOINFO_TCP_STATE] = { .type = NLA_U8 },
1234 [CTA_PROTOINFO_TCP_WSCALE_ORIGINAL] = { .type = NLA_U8 },
1235 [CTA_PROTOINFO_TCP_WSCALE_REPLY] = { .type = NLA_U8 },
1236 [CTA_PROTOINFO_TCP_FLAGS_ORIGINAL] = { .len = sizeof(struct nf_ct_tcp_flags) },
1237 [CTA_PROTOINFO_TCP_FLAGS_REPLY] = { .len = sizeof(struct nf_ct_tcp_flags) },
1240 #define TCP_NLATTR_SIZE ( \
1241 NLA_ALIGN(NLA_HDRLEN + 1) + \
1242 NLA_ALIGN(NLA_HDRLEN + 1) + \
1243 NLA_ALIGN(NLA_HDRLEN + sizeof(struct nf_ct_tcp_flags)) + \
1244 NLA_ALIGN(NLA_HDRLEN + sizeof(struct nf_ct_tcp_flags)))
1246 static int nlattr_to_tcp(struct nlattr *cda[], struct nf_conn *ct)
1248 struct nlattr *pattr = cda[CTA_PROTOINFO_TCP];
1249 struct nlattr *tb[CTA_PROTOINFO_TCP_MAX+1];
1252 /* updates could not contain anything about the private
1253 * protocol info, in that case skip the parsing */
1257 err = nla_parse_nested_deprecated(tb, CTA_PROTOINFO_TCP_MAX, pattr,
1258 tcp_nla_policy, NULL);
1262 if (tb[CTA_PROTOINFO_TCP_STATE] &&
1263 nla_get_u8(tb[CTA_PROTOINFO_TCP_STATE]) >= TCP_CONNTRACK_MAX)
1266 spin_lock_bh(&ct->lock);
1267 if (tb[CTA_PROTOINFO_TCP_STATE])
1268 ct->proto.tcp.state = nla_get_u8(tb[CTA_PROTOINFO_TCP_STATE]);
1270 if (tb[CTA_PROTOINFO_TCP_FLAGS_ORIGINAL]) {
1271 struct nf_ct_tcp_flags *attr =
1272 nla_data(tb[CTA_PROTOINFO_TCP_FLAGS_ORIGINAL]);
1273 ct->proto.tcp.seen[0].flags &= ~attr->mask;
1274 ct->proto.tcp.seen[0].flags |= attr->flags & attr->mask;
1277 if (tb[CTA_PROTOINFO_TCP_FLAGS_REPLY]) {
1278 struct nf_ct_tcp_flags *attr =
1279 nla_data(tb[CTA_PROTOINFO_TCP_FLAGS_REPLY]);
1280 ct->proto.tcp.seen[1].flags &= ~attr->mask;
1281 ct->proto.tcp.seen[1].flags |= attr->flags & attr->mask;
1284 if (tb[CTA_PROTOINFO_TCP_WSCALE_ORIGINAL] &&
1285 tb[CTA_PROTOINFO_TCP_WSCALE_REPLY] &&
1286 ct->proto.tcp.seen[0].flags & IP_CT_TCP_FLAG_WINDOW_SCALE &&
1287 ct->proto.tcp.seen[1].flags & IP_CT_TCP_FLAG_WINDOW_SCALE) {
1288 ct->proto.tcp.seen[0].td_scale =
1289 nla_get_u8(tb[CTA_PROTOINFO_TCP_WSCALE_ORIGINAL]);
1290 ct->proto.tcp.seen[1].td_scale =
1291 nla_get_u8(tb[CTA_PROTOINFO_TCP_WSCALE_REPLY]);
1293 spin_unlock_bh(&ct->lock);
1298 static unsigned int tcp_nlattr_tuple_size(void)
1300 static unsigned int size __read_mostly;
1303 size = nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1);
1309 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
1311 #include <linux/netfilter/nfnetlink.h>
1312 #include <linux/netfilter/nfnetlink_cttimeout.h>
1314 static int tcp_timeout_nlattr_to_obj(struct nlattr *tb[],
1315 struct net *net, void *data)
1317 struct nf_tcp_net *tn = nf_tcp_pernet(net);
1318 unsigned int *timeouts = data;
1322 timeouts = tn->timeouts;
1323 /* set default TCP timeouts. */
1324 for (i=0; i<TCP_CONNTRACK_TIMEOUT_MAX; i++)
1325 timeouts[i] = tn->timeouts[i];
1327 if (tb[CTA_TIMEOUT_TCP_SYN_SENT]) {
1328 timeouts[TCP_CONNTRACK_SYN_SENT] =
1329 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_SYN_SENT]))*HZ;
1332 if (tb[CTA_TIMEOUT_TCP_SYN_RECV]) {
1333 timeouts[TCP_CONNTRACK_SYN_RECV] =
1334 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_SYN_RECV]))*HZ;
1336 if (tb[CTA_TIMEOUT_TCP_ESTABLISHED]) {
1337 timeouts[TCP_CONNTRACK_ESTABLISHED] =
1338 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_ESTABLISHED]))*HZ;
1340 if (tb[CTA_TIMEOUT_TCP_FIN_WAIT]) {
1341 timeouts[TCP_CONNTRACK_FIN_WAIT] =
1342 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_FIN_WAIT]))*HZ;
1344 if (tb[CTA_TIMEOUT_TCP_CLOSE_WAIT]) {
1345 timeouts[TCP_CONNTRACK_CLOSE_WAIT] =
1346 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_CLOSE_WAIT]))*HZ;
1348 if (tb[CTA_TIMEOUT_TCP_LAST_ACK]) {
1349 timeouts[TCP_CONNTRACK_LAST_ACK] =
1350 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_LAST_ACK]))*HZ;
1352 if (tb[CTA_TIMEOUT_TCP_TIME_WAIT]) {
1353 timeouts[TCP_CONNTRACK_TIME_WAIT] =
1354 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_TIME_WAIT]))*HZ;
1356 if (tb[CTA_TIMEOUT_TCP_CLOSE]) {
1357 timeouts[TCP_CONNTRACK_CLOSE] =
1358 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_CLOSE]))*HZ;
1360 if (tb[CTA_TIMEOUT_TCP_SYN_SENT2]) {
1361 timeouts[TCP_CONNTRACK_SYN_SENT2] =
1362 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_SYN_SENT2]))*HZ;
1364 if (tb[CTA_TIMEOUT_TCP_RETRANS]) {
1365 timeouts[TCP_CONNTRACK_RETRANS] =
1366 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_RETRANS]))*HZ;
1368 if (tb[CTA_TIMEOUT_TCP_UNACK]) {
1369 timeouts[TCP_CONNTRACK_UNACK] =
1370 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_UNACK]))*HZ;
1373 timeouts[CTA_TIMEOUT_TCP_UNSPEC] = timeouts[CTA_TIMEOUT_TCP_SYN_SENT];
1378 tcp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
1380 const unsigned int *timeouts = data;
1382 if (nla_put_be32(skb, CTA_TIMEOUT_TCP_SYN_SENT,
1383 htonl(timeouts[TCP_CONNTRACK_SYN_SENT] / HZ)) ||
1384 nla_put_be32(skb, CTA_TIMEOUT_TCP_SYN_RECV,
1385 htonl(timeouts[TCP_CONNTRACK_SYN_RECV] / HZ)) ||
1386 nla_put_be32(skb, CTA_TIMEOUT_TCP_ESTABLISHED,
1387 htonl(timeouts[TCP_CONNTRACK_ESTABLISHED] / HZ)) ||
1388 nla_put_be32(skb, CTA_TIMEOUT_TCP_FIN_WAIT,
1389 htonl(timeouts[TCP_CONNTRACK_FIN_WAIT] / HZ)) ||
1390 nla_put_be32(skb, CTA_TIMEOUT_TCP_CLOSE_WAIT,
1391 htonl(timeouts[TCP_CONNTRACK_CLOSE_WAIT] / HZ)) ||
1392 nla_put_be32(skb, CTA_TIMEOUT_TCP_LAST_ACK,
1393 htonl(timeouts[TCP_CONNTRACK_LAST_ACK] / HZ)) ||
1394 nla_put_be32(skb, CTA_TIMEOUT_TCP_TIME_WAIT,
1395 htonl(timeouts[TCP_CONNTRACK_TIME_WAIT] / HZ)) ||
1396 nla_put_be32(skb, CTA_TIMEOUT_TCP_CLOSE,
1397 htonl(timeouts[TCP_CONNTRACK_CLOSE] / HZ)) ||
1398 nla_put_be32(skb, CTA_TIMEOUT_TCP_SYN_SENT2,
1399 htonl(timeouts[TCP_CONNTRACK_SYN_SENT2] / HZ)) ||
1400 nla_put_be32(skb, CTA_TIMEOUT_TCP_RETRANS,
1401 htonl(timeouts[TCP_CONNTRACK_RETRANS] / HZ)) ||
1402 nla_put_be32(skb, CTA_TIMEOUT_TCP_UNACK,
1403 htonl(timeouts[TCP_CONNTRACK_UNACK] / HZ)))
1404 goto nla_put_failure;
1411 static const struct nla_policy tcp_timeout_nla_policy[CTA_TIMEOUT_TCP_MAX+1] = {
1412 [CTA_TIMEOUT_TCP_SYN_SENT] = { .type = NLA_U32 },
1413 [CTA_TIMEOUT_TCP_SYN_RECV] = { .type = NLA_U32 },
1414 [CTA_TIMEOUT_TCP_ESTABLISHED] = { .type = NLA_U32 },
1415 [CTA_TIMEOUT_TCP_FIN_WAIT] = { .type = NLA_U32 },
1416 [CTA_TIMEOUT_TCP_CLOSE_WAIT] = { .type = NLA_U32 },
1417 [CTA_TIMEOUT_TCP_LAST_ACK] = { .type = NLA_U32 },
1418 [CTA_TIMEOUT_TCP_TIME_WAIT] = { .type = NLA_U32 },
1419 [CTA_TIMEOUT_TCP_CLOSE] = { .type = NLA_U32 },
1420 [CTA_TIMEOUT_TCP_SYN_SENT2] = { .type = NLA_U32 },
1421 [CTA_TIMEOUT_TCP_RETRANS] = { .type = NLA_U32 },
1422 [CTA_TIMEOUT_TCP_UNACK] = { .type = NLA_U32 },
1424 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
1426 void nf_conntrack_tcp_init_net(struct net *net)
1428 struct nf_tcp_net *tn = nf_tcp_pernet(net);
1431 for (i = 0; i < TCP_CONNTRACK_TIMEOUT_MAX; i++)
1432 tn->timeouts[i] = tcp_timeouts[i];
1434 /* timeouts[0] is unused, make it same as SYN_SENT so
1435 * ->timeouts[0] contains 'new' timeout, like udp or icmp.
1437 tn->timeouts[0] = tcp_timeouts[TCP_CONNTRACK_SYN_SENT];
1438 tn->tcp_loose = nf_ct_tcp_loose;
1439 tn->tcp_be_liberal = nf_ct_tcp_be_liberal;
1440 tn->tcp_max_retrans = nf_ct_tcp_max_retrans;
1443 const struct nf_conntrack_l4proto nf_conntrack_l4proto_tcp =
1445 .l4proto = IPPROTO_TCP,
1446 #ifdef CONFIG_NF_CONNTRACK_PROCFS
1447 .print_conntrack = tcp_print_conntrack,
1449 .can_early_drop = tcp_can_early_drop,
1450 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
1451 .to_nlattr = tcp_to_nlattr,
1452 .from_nlattr = nlattr_to_tcp,
1453 .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
1454 .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
1455 .nlattr_tuple_size = tcp_nlattr_tuple_size,
1456 .nlattr_size = TCP_NLATTR_SIZE,
1457 .nla_policy = nf_ct_port_nla_policy,
1459 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
1461 .nlattr_to_obj = tcp_timeout_nlattr_to_obj,
1462 .obj_to_nlattr = tcp_timeout_obj_to_nlattr,
1463 .nlattr_max = CTA_TIMEOUT_TCP_MAX,
1464 .obj_size = sizeof(unsigned int) *
1465 TCP_CONNTRACK_TIMEOUT_MAX,
1466 .nla_policy = tcp_timeout_nla_policy,
1468 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */