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>
6 */
7
8#include <linux/types.h>
9#include <linux/timer.h>
10#include <linux/module.h>
11#include <linux/in.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 <linux/unaligned.h>
18
19#include <net/tcp.h>
20
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>
33
34 /* FIXME: Examine ipfilter's timeouts and conntrack transitions more
35 closely. They're more complex. --RR */
36
37static const char *const tcp_conntrack_names[] = {
38 "NONE",
39 "SYN_SENT",
40 "SYN_RECV",
41 "ESTABLISHED",
42 "FIN_WAIT",
43 "CLOSE_WAIT",
44 "LAST_ACK",
45 "TIME_WAIT",
46 "CLOSE",
47 "SYN_SENT2",
48};
49
50enum nf_ct_tcp_action {
51 NFCT_TCP_IGNORE,
52 NFCT_TCP_INVALID,
53 NFCT_TCP_ACCEPT,
54};
55
56#define SECS * HZ
57#define MINS * 60 SECS
58#define HOURS * 60 MINS
59#define DAYS * 24 HOURS
60
61static const unsigned int tcp_timeouts[TCP_CONNTRACK_TIMEOUT_MAX] = {
62 [TCP_CONNTRACK_SYN_SENT] = 2 MINS,
63 [TCP_CONNTRACK_SYN_RECV] = 60 SECS,
64 [TCP_CONNTRACK_ESTABLISHED] = 5 DAYS,
65 [TCP_CONNTRACK_FIN_WAIT] = 2 MINS,
66 [TCP_CONNTRACK_CLOSE_WAIT] = 60 SECS,
67 [TCP_CONNTRACK_LAST_ACK] = 30 SECS,
68 [TCP_CONNTRACK_TIME_WAIT] = 2 MINS,
69 [TCP_CONNTRACK_CLOSE] = 10 SECS,
70 [TCP_CONNTRACK_SYN_SENT2] = 2 MINS,
71/* RFC1122 says the R2 limit should be at least 100 seconds.
72 Linux uses 15 packets as limit, which corresponds
73 to ~13-30min depending on RTO. */
74 [TCP_CONNTRACK_RETRANS] = 5 MINS,
75 [TCP_CONNTRACK_UNACK] = 5 MINS,
76};
77
78#define sNO TCP_CONNTRACK_NONE
79#define sSS TCP_CONNTRACK_SYN_SENT
80#define sSR TCP_CONNTRACK_SYN_RECV
81#define sES TCP_CONNTRACK_ESTABLISHED
82#define sFW TCP_CONNTRACK_FIN_WAIT
83#define sCW TCP_CONNTRACK_CLOSE_WAIT
84#define sLA TCP_CONNTRACK_LAST_ACK
85#define sTW TCP_CONNTRACK_TIME_WAIT
86#define sCL TCP_CONNTRACK_CLOSE
87#define sS2 TCP_CONNTRACK_SYN_SENT2
88#define sIV TCP_CONNTRACK_MAX
89#define sIG TCP_CONNTRACK_IGNORE
90
91/* What TCP flags are set from RST/SYN/FIN/ACK. */
92enum tcp_bit_set {
93 TCP_SYN_SET,
94 TCP_SYNACK_SET,
95 TCP_FIN_SET,
96 TCP_ACK_SET,
97 TCP_RST_SET,
98 TCP_NONE_SET,
99};
100
101/*
102 * The TCP state transition table needs a few words...
103 *
104 * We are the man in the middle. All the packets go through us
105 * but might get lost in transit to the destination.
106 * It is assumed that the destinations can't receive segments
107 * we haven't seen.
108 *
109 * The checked segment is in window, but our windows are *not*
110 * equivalent with the ones of the sender/receiver. We always
111 * try to guess the state of the current sender.
112 *
113 * The meaning of the states are:
114 *
115 * NONE: initial state
116 * SYN_SENT: SYN-only packet seen
117 * SYN_SENT2: SYN-only packet seen from reply dir, simultaneous open
118 * SYN_RECV: SYN-ACK packet seen
119 * ESTABLISHED: ACK packet seen
120 * FIN_WAIT: FIN packet seen
121 * CLOSE_WAIT: ACK seen (after FIN)
122 * LAST_ACK: FIN seen (after FIN)
123 * TIME_WAIT: last ACK seen
124 * CLOSE: closed connection (RST)
125 *
126 * Packets marked as IGNORED (sIG):
127 * if they may be either invalid or valid
128 * and the receiver may send back a connection
129 * closing RST or a SYN/ACK.
130 *
131 * Packets marked as INVALID (sIV):
132 * if we regard them as truly invalid packets
133 */
134static const u8 tcp_conntracks[2][6][TCP_CONNTRACK_MAX] = {
135 {
136/* ORIGINAL */
137/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
138/*syn*/ { sSS, sSS, sIG, sIG, sIG, sIG, sIG, sSS, sSS, sS2 },
139/*
140 * sNO -> sSS Initialize a new connection
141 * sSS -> sSS Retransmitted SYN
142 * sS2 -> sS2 Late retransmitted SYN
143 * sSR -> sIG
144 * sES -> sIG Error: SYNs in window outside the SYN_SENT state
145 * are errors. Receiver will reply with RST
146 * and close the connection.
147 * Or we are not in sync and hold a dead connection.
148 * sFW -> sIG
149 * sCW -> sIG
150 * sLA -> sIG
151 * sTW -> sSS Reopened connection (RFC 1122).
152 * sCL -> sSS
153 */
154/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
155/*synack*/ { sIV, sIV, sSR, sIV, sIV, sIV, sIV, sIV, sIV, sSR },
156/*
157 * sNO -> sIV Too late and no reason to do anything
158 * sSS -> sIV Client can't send SYN and then SYN/ACK
159 * sS2 -> sSR SYN/ACK sent to SYN2 in simultaneous open
160 * sSR -> sSR Late retransmitted SYN/ACK in simultaneous open
161 * sES -> sIV Invalid SYN/ACK packets sent by the client
162 * sFW -> sIV
163 * sCW -> sIV
164 * sLA -> sIV
165 * sTW -> sIV
166 * sCL -> sIV
167 */
168/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
169/*fin*/ { sIV, sIV, sFW, sFW, sLA, sLA, sLA, sTW, sCL, sIV },
170/*
171 * sNO -> sIV Too late and no reason to do anything...
172 * sSS -> sIV Client migth not send FIN in this state:
173 * we enforce waiting for a SYN/ACK reply first.
174 * sS2 -> sIV
175 * sSR -> sFW Close started.
176 * sES -> sFW
177 * sFW -> sLA FIN seen in both directions, waiting for
178 * the last ACK.
179 * Migth be a retransmitted FIN as well...
180 * sCW -> sLA
181 * sLA -> sLA Retransmitted FIN. Remain in the same state.
182 * sTW -> sTW
183 * sCL -> sCL
184 */
185/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
186/*ack*/ { sES, sIV, sES, sES, sCW, sCW, sTW, sTW, sCL, sIV },
187/*
188 * sNO -> sES Assumed.
189 * sSS -> sIV ACK is invalid: we haven't seen a SYN/ACK yet.
190 * sS2 -> sIV
191 * sSR -> sES Established state is reached.
192 * sES -> sES :-)
193 * sFW -> sCW Normal close request answered by ACK.
194 * sCW -> sCW
195 * sLA -> sTW Last ACK detected (RFC5961 challenged)
196 * sTW -> sTW Retransmitted last ACK. Remain in the same state.
197 * sCL -> sCL
198 */
199/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
200/*rst*/ { sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL },
201/*none*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV }
202 },
203 {
204/* REPLY */
205/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
206/*syn*/ { sIV, sS2, sIV, sIV, sIV, sIV, sIV, sSS, sIV, sS2 },
207/*
208 * sNO -> sIV Never reached.
209 * sSS -> sS2 Simultaneous open
210 * sS2 -> sS2 Retransmitted simultaneous SYN
211 * sSR -> sIV Invalid SYN packets sent by the server
212 * sES -> sIV
213 * sFW -> sIV
214 * sCW -> sIV
215 * sLA -> sIV
216 * sTW -> sSS Reopened connection, but server may have switched role
217 * sCL -> sIV
218 */
219/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
220/*synack*/ { sIV, sSR, sIG, sIG, sIG, sIG, sIG, sIG, sIG, sSR },
221/*
222 * sSS -> sSR Standard open.
223 * sS2 -> sSR Simultaneous open
224 * sSR -> sIG Retransmitted SYN/ACK, ignore it.
225 * sES -> sIG Late retransmitted SYN/ACK?
226 * sFW -> sIG Might be SYN/ACK answering ignored SYN
227 * sCW -> sIG
228 * sLA -> sIG
229 * sTW -> sIG
230 * sCL -> sIG
231 */
232/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
233/*fin*/ { sIV, sIV, sFW, sFW, sLA, sLA, sLA, sTW, sCL, sIV },
234/*
235 * sSS -> sIV Server might not send FIN in this state.
236 * sS2 -> sIV
237 * sSR -> sFW Close started.
238 * sES -> sFW
239 * sFW -> sLA FIN seen in both directions.
240 * sCW -> sLA
241 * sLA -> sLA Retransmitted FIN.
242 * sTW -> sTW
243 * sCL -> sCL
244 */
245/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
246/*ack*/ { sIV, sIG, sSR, sES, sCW, sCW, sTW, sTW, sCL, sIG },
247/*
248 * sSS -> sIG Might be a half-open connection.
249 * sS2 -> sIG
250 * sSR -> sSR Might answer late resent SYN.
251 * sES -> sES :-)
252 * sFW -> sCW Normal close request answered by ACK.
253 * sCW -> sCW
254 * sLA -> sTW Last ACK detected (RFC5961 challenged)
255 * sTW -> sTW Retransmitted last ACK.
256 * sCL -> sCL
257 */
258/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
259/*rst*/ { sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL },
260/*none*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV }
261 }
262};
263
264#ifdef CONFIG_NF_CONNTRACK_PROCFS
265/* Print out the private part of the conntrack. */
266static void tcp_print_conntrack(struct seq_file *s, struct nf_conn *ct)
267{
268 if (test_bit(IPS_OFFLOAD_BIT, &ct->status))
269 return;
270
271 seq_printf(s, "%s ", tcp_conntrack_names[ct->proto.tcp.state]);
272}
273#endif
274
275static unsigned int get_conntrack_index(const struct tcphdr *tcph)
276{
277 if (tcph->rst) return TCP_RST_SET;
278 else if (tcph->syn) return (tcph->ack ? TCP_SYNACK_SET : TCP_SYN_SET);
279 else if (tcph->fin) return TCP_FIN_SET;
280 else if (tcph->ack) return TCP_ACK_SET;
281 else return TCP_NONE_SET;
282}
283
284/* TCP connection tracking based on 'Real Stateful TCP Packet Filtering
285 in IP Filter' by Guido van Rooij.
286
287 http://www.sane.nl/events/sane2000/papers.html
288 http://www.darkart.com/mirrors/www.obfuscation.org/ipf/
289
290 The boundaries and the conditions are changed according to RFC793:
291 the packet must intersect the window (i.e. segments may be
292 after the right or before the left edge) and thus receivers may ACK
293 segments after the right edge of the window.
294
295 td_maxend = max(sack + max(win,1)) seen in reply packets
296 td_maxwin = max(max(win, 1)) + (sack - ack) seen in sent packets
297 td_maxwin += seq + len - sender.td_maxend
298 if seq + len > sender.td_maxend
299 td_end = max(seq + len) seen in sent packets
300
301 I. Upper bound for valid data: seq <= sender.td_maxend
302 II. Lower bound for valid data: seq + len >= sender.td_end - receiver.td_maxwin
303 III. Upper bound for valid (s)ack: sack <= receiver.td_end
304 IV. Lower bound for valid (s)ack: sack >= receiver.td_end - MAXACKWINDOW
305
306 where sack is the highest right edge of sack block found in the packet
307 or ack in the case of packet without SACK option.
308
309 The upper bound limit for a valid (s)ack is not ignored -
310 we doesn't have to deal with fragments.
311*/
312
313static inline __u32 segment_seq_plus_len(__u32 seq,
314 size_t len,
315 unsigned int dataoff,
316 const struct tcphdr *tcph)
317{
318 /* XXX Should I use payload length field in IP/IPv6 header ?
319 * - YK */
320 return (seq + len - dataoff - tcph->doff*4
321 + (tcph->syn ? 1 : 0) + (tcph->fin ? 1 : 0));
322}
323
324/* Fixme: what about big packets? */
325#define MAXACKWINCONST 66000
326#define MAXACKWINDOW(sender) \
327 ((sender)->td_maxwin > MAXACKWINCONST ? (sender)->td_maxwin \
328 : MAXACKWINCONST)
329
330/*
331 * Simplified tcp_parse_options routine from tcp_input.c
332 */
333static void tcp_options(const struct sk_buff *skb,
334 unsigned int dataoff,
335 const struct tcphdr *tcph,
336 struct ip_ct_tcp_state *state)
337{
338 unsigned char buff[(15 * 4) - sizeof(struct tcphdr)];
339 const unsigned char *ptr;
340 int length = (tcph->doff*4) - sizeof(struct tcphdr);
341
342 if (!length)
343 return;
344
345 ptr = skb_header_pointer(skb, offset: dataoff + sizeof(struct tcphdr),
346 len: length, buffer: buff);
347 if (!ptr)
348 return;
349
350 state->td_scale = 0;
351 state->flags &= IP_CT_TCP_FLAG_BE_LIBERAL;
352
353 while (length > 0) {
354 int opcode=*ptr++;
355 int opsize;
356
357 switch (opcode) {
358 case TCPOPT_EOL:
359 return;
360 case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */
361 length--;
362 continue;
363 default:
364 if (length < 2)
365 return;
366 opsize=*ptr++;
367 if (opsize < 2) /* "silly options" */
368 return;
369 if (opsize > length)
370 return; /* don't parse partial options */
371
372 if (opcode == TCPOPT_SACK_PERM
373 && opsize == TCPOLEN_SACK_PERM)
374 state->flags |= IP_CT_TCP_FLAG_SACK_PERM;
375 else if (opcode == TCPOPT_WINDOW
376 && opsize == TCPOLEN_WINDOW) {
377 state->td_scale = *(u_int8_t *)ptr;
378
379 if (state->td_scale > TCP_MAX_WSCALE)
380 state->td_scale = TCP_MAX_WSCALE;
381
382 state->flags |=
383 IP_CT_TCP_FLAG_WINDOW_SCALE;
384 }
385 ptr += opsize - 2;
386 length -= opsize;
387 }
388 }
389}
390
391static void tcp_sack(const struct sk_buff *skb, unsigned int dataoff,
392 const struct tcphdr *tcph, __u32 *sack)
393{
394 unsigned char buff[(15 * 4) - sizeof(struct tcphdr)];
395 const unsigned char *ptr;
396 int length = (tcph->doff*4) - sizeof(struct tcphdr);
397 __u32 tmp;
398
399 if (!length)
400 return;
401
402 ptr = skb_header_pointer(skb, offset: dataoff + sizeof(struct tcphdr),
403 len: length, buffer: buff);
404 if (!ptr)
405 return;
406
407 /* Fast path for timestamp-only option */
408 if (length == TCPOLEN_TSTAMP_ALIGNED
409 && *(__be32 *)ptr == htonl((TCPOPT_NOP << 24)
410 | (TCPOPT_NOP << 16)
411 | (TCPOPT_TIMESTAMP << 8)
412 | TCPOLEN_TIMESTAMP))
413 return;
414
415 while (length > 0) {
416 int opcode = *ptr++;
417 int opsize, i;
418
419 switch (opcode) {
420 case TCPOPT_EOL:
421 return;
422 case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */
423 length--;
424 continue;
425 default:
426 if (length < 2)
427 return;
428 opsize = *ptr++;
429 if (opsize < 2) /* "silly options" */
430 return;
431 if (opsize > length)
432 return; /* don't parse partial options */
433
434 if (opcode == TCPOPT_SACK
435 && opsize >= (TCPOLEN_SACK_BASE
436 + TCPOLEN_SACK_PERBLOCK)
437 && !((opsize - TCPOLEN_SACK_BASE)
438 % TCPOLEN_SACK_PERBLOCK)) {
439 for (i = 0;
440 i < (opsize - TCPOLEN_SACK_BASE);
441 i += TCPOLEN_SACK_PERBLOCK) {
442 tmp = get_unaligned_be32(p: (__be32 *)(ptr+i)+1);
443
444 if (after(tmp, *sack))
445 *sack = tmp;
446 }
447 return;
448 }
449 ptr += opsize - 2;
450 length -= opsize;
451 }
452 }
453}
454
455static void tcp_init_sender(struct ip_ct_tcp_state *sender,
456 struct ip_ct_tcp_state *receiver,
457 const struct sk_buff *skb,
458 unsigned int dataoff,
459 const struct tcphdr *tcph,
460 u32 end, u32 win,
461 enum ip_conntrack_dir dir)
462{
463 /* SYN-ACK in reply to a SYN
464 * or SYN from reply direction in simultaneous open.
465 */
466 sender->td_end =
467 sender->td_maxend = end;
468 sender->td_maxwin = (win == 0 ? 1 : win);
469
470 tcp_options(skb, dataoff, tcph, state: sender);
471 /* RFC 1323:
472 * Both sides must send the Window Scale option
473 * to enable window scaling in either direction.
474 */
475 if (dir == IP_CT_DIR_REPLY &&
476 !(sender->flags & IP_CT_TCP_FLAG_WINDOW_SCALE &&
477 receiver->flags & IP_CT_TCP_FLAG_WINDOW_SCALE)) {
478 sender->td_scale = 0;
479 receiver->td_scale = 0;
480 }
481}
482
483__printf(6, 7)
484static enum nf_ct_tcp_action nf_tcp_log_invalid(const struct sk_buff *skb,
485 const struct nf_conn *ct,
486 const struct nf_hook_state *state,
487 const struct ip_ct_tcp_state *sender,
488 enum nf_ct_tcp_action ret,
489 const char *fmt, ...)
490{
491 const struct nf_tcp_net *tn = nf_tcp_pernet(net: nf_ct_net(ct));
492 struct va_format vaf;
493 va_list args;
494 bool be_liberal;
495
496 be_liberal = sender->flags & IP_CT_TCP_FLAG_BE_LIBERAL || tn->tcp_be_liberal;
497 if (be_liberal)
498 return NFCT_TCP_ACCEPT;
499
500 va_start(args, fmt);
501 vaf.fmt = fmt;
502 vaf.va = &args;
503 nf_ct_l4proto_log_invalid(skb, ct, state, fmt: "%pV", &vaf);
504 va_end(args);
505
506 return ret;
507}
508
509static enum nf_ct_tcp_action
510tcp_in_window(struct nf_conn *ct, enum ip_conntrack_dir dir,
511 unsigned int index, const struct sk_buff *skb,
512 unsigned int dataoff, const struct tcphdr *tcph,
513 const struct nf_hook_state *hook_state)
514{
515 struct ip_ct_tcp *state = &ct->proto.tcp;
516 struct ip_ct_tcp_state *sender = &state->seen[dir];
517 struct ip_ct_tcp_state *receiver = &state->seen[!dir];
518 __u32 seq, ack, sack, end, win, swin;
519 bool in_recv_win, seq_ok;
520 s32 receiver_offset;
521 u16 win_raw;
522
523 /*
524 * Get the required data from the packet.
525 */
526 seq = ntohl(tcph->seq);
527 ack = sack = ntohl(tcph->ack_seq);
528 win_raw = ntohs(tcph->window);
529 win = win_raw;
530 end = segment_seq_plus_len(seq, len: skb->len, dataoff, tcph);
531
532 if (receiver->flags & IP_CT_TCP_FLAG_SACK_PERM)
533 tcp_sack(skb, dataoff, tcph, sack: &sack);
534
535 /* Take into account NAT sequence number mangling */
536 receiver_offset = nf_ct_seq_offset(ct, !dir, seq: ack - 1);
537 ack -= receiver_offset;
538 sack -= receiver_offset;
539
540 if (sender->td_maxwin == 0) {
541 /*
542 * Initialize sender data.
543 */
544 if (tcph->syn) {
545 tcp_init_sender(sender, receiver,
546 skb, dataoff, tcph,
547 end, win, dir);
548 if (!tcph->ack)
549 /* Simultaneous open */
550 return NFCT_TCP_ACCEPT;
551 } else {
552 /*
553 * We are in the middle of a connection,
554 * its history is lost for us.
555 * Let's try to use the data from the packet.
556 */
557 sender->td_end = end;
558 swin = win << sender->td_scale;
559 sender->td_maxwin = (swin == 0 ? 1 : swin);
560 sender->td_maxend = end + sender->td_maxwin;
561 if (receiver->td_maxwin == 0) {
562 /* We haven't seen traffic in the other
563 * direction yet but we have to tweak window
564 * tracking to pass III and IV until that
565 * happens.
566 */
567 receiver->td_end = receiver->td_maxend = sack;
568 } else if (sack == receiver->td_end + 1) {
569 /* Likely a reply to a keepalive.
570 * Needed for III.
571 */
572 receiver->td_end++;
573 }
574
575 }
576 } else if (tcph->syn &&
577 after(end, sender->td_end) &&
578 (state->state == TCP_CONNTRACK_SYN_SENT ||
579 state->state == TCP_CONNTRACK_SYN_RECV)) {
580 /*
581 * RFC 793: "if a TCP is reinitialized ... then it need
582 * not wait at all; it must only be sure to use sequence
583 * numbers larger than those recently used."
584 *
585 * Re-init state for this direction, just like for the first
586 * syn(-ack) reply, it might differ in seq, ack or tcp options.
587 */
588 tcp_init_sender(sender, receiver,
589 skb, dataoff, tcph,
590 end, win, dir);
591
592 if (dir == IP_CT_DIR_REPLY && !tcph->ack)
593 return NFCT_TCP_ACCEPT;
594 }
595
596 if (!(tcph->ack)) {
597 /*
598 * If there is no ACK, just pretend it was set and OK.
599 */
600 ack = sack = receiver->td_end;
601 } else if (((tcp_flag_word(tcph) & (TCP_FLAG_ACK|TCP_FLAG_RST)) ==
602 (TCP_FLAG_ACK|TCP_FLAG_RST))
603 && (ack == 0)) {
604 /*
605 * Broken TCP stacks, that set ACK in RST packets as well
606 * with zero ack value.
607 */
608 ack = sack = receiver->td_end;
609 }
610
611 if (tcph->rst && seq == 0 && state->state == TCP_CONNTRACK_SYN_SENT)
612 /*
613 * RST sent answering SYN.
614 */
615 seq = end = sender->td_end;
616
617 seq_ok = before(seq1: seq, seq2: sender->td_maxend + 1);
618 if (!seq_ok) {
619 u32 overshot = end - sender->td_maxend + 1;
620 bool ack_ok;
621
622 ack_ok = after(sack, receiver->td_end - MAXACKWINDOW(sender) - 1);
623 in_recv_win = receiver->td_maxwin &&
624 after(end, sender->td_end - receiver->td_maxwin - 1);
625
626 if (in_recv_win &&
627 ack_ok &&
628 overshot <= receiver->td_maxwin &&
629 before(seq1: sack, seq2: receiver->td_end + 1)) {
630 /* Work around TCPs that send more bytes than allowed by
631 * the receive window.
632 *
633 * If the (marked as invalid) packet is allowed to pass by
634 * the ruleset and the peer acks this data, then its possible
635 * all future packets will trigger 'ACK is over upper bound' check.
636 *
637 * Thus if only the sequence check fails then do update td_end so
638 * possible ACK for this data can update internal state.
639 */
640 sender->td_end = end;
641 sender->flags |= IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED;
642
643 return nf_tcp_log_invalid(skb, ct, state: hook_state, sender, ret: NFCT_TCP_IGNORE,
644 fmt: "%u bytes more than expected", overshot);
645 }
646
647 return nf_tcp_log_invalid(skb, ct, state: hook_state, sender, ret: NFCT_TCP_INVALID,
648 fmt: "SEQ is over upper bound %u (over the window of the receiver)",
649 sender->td_maxend + 1);
650 }
651
652 if (!before(seq1: sack, seq2: receiver->td_end + 1))
653 return nf_tcp_log_invalid(skb, ct, state: hook_state, sender, ret: NFCT_TCP_INVALID,
654 fmt: "ACK is over upper bound %u (ACKed data not seen yet)",
655 receiver->td_end + 1);
656
657 /* Is the ending sequence in the receive window (if available)? */
658 in_recv_win = !receiver->td_maxwin ||
659 after(end, sender->td_end - receiver->td_maxwin - 1);
660 if (!in_recv_win)
661 return nf_tcp_log_invalid(skb, ct, state: hook_state, sender, ret: NFCT_TCP_IGNORE,
662 fmt: "SEQ is under lower bound %u (already ACKed data retransmitted)",
663 sender->td_end - receiver->td_maxwin - 1);
664 if (!after(sack, receiver->td_end - MAXACKWINDOW(sender) - 1))
665 return nf_tcp_log_invalid(skb, ct, state: hook_state, sender, ret: NFCT_TCP_IGNORE,
666 fmt: "ignored ACK under lower bound %u (possible overly delayed)",
667 receiver->td_end - MAXACKWINDOW(sender) - 1);
668
669 /* Take into account window scaling (RFC 1323). */
670 if (!tcph->syn)
671 win <<= sender->td_scale;
672
673 /* Update sender data. */
674 swin = win + (sack - ack);
675 if (sender->td_maxwin < swin)
676 sender->td_maxwin = swin;
677 if (after(end, sender->td_end)) {
678 sender->td_end = end;
679 sender->flags |= IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED;
680 }
681 if (tcph->ack) {
682 if (!(sender->flags & IP_CT_TCP_FLAG_MAXACK_SET)) {
683 sender->td_maxack = ack;
684 sender->flags |= IP_CT_TCP_FLAG_MAXACK_SET;
685 } else if (after(ack, sender->td_maxack)) {
686 sender->td_maxack = ack;
687 }
688 }
689
690 /* Update receiver data. */
691 if (receiver->td_maxwin != 0 && after(end, sender->td_maxend))
692 receiver->td_maxwin += end - sender->td_maxend;
693 if (after(sack + win, receiver->td_maxend - 1)) {
694 receiver->td_maxend = sack + win;
695 if (win == 0)
696 receiver->td_maxend++;
697 }
698 if (ack == receiver->td_end)
699 receiver->flags &= ~IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED;
700
701 /* Check retransmissions. */
702 if (index == TCP_ACK_SET) {
703 if (state->last_dir == dir &&
704 state->last_seq == seq &&
705 state->last_ack == ack &&
706 state->last_end == end &&
707 state->last_win == win_raw) {
708 state->retrans++;
709 } else {
710 state->last_dir = dir;
711 state->last_seq = seq;
712 state->last_ack = ack;
713 state->last_end = end;
714 state->last_win = win_raw;
715 state->retrans = 0;
716 }
717 }
718
719 return NFCT_TCP_ACCEPT;
720}
721
722static void __cold nf_tcp_handle_invalid(struct nf_conn *ct,
723 enum ip_conntrack_dir dir,
724 int index,
725 const struct sk_buff *skb,
726 const struct nf_hook_state *hook_state)
727{
728 const unsigned int *timeouts;
729 const struct nf_tcp_net *tn;
730 unsigned int timeout;
731 u32 expires;
732
733 if (!test_bit(IPS_ASSURED_BIT, &ct->status) ||
734 test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status))
735 return;
736
737 /* We don't want to have connections hanging around in ESTABLISHED
738 * state for long time 'just because' conntrack deemed a FIN/RST
739 * out-of-window.
740 *
741 * Shrink the timeout just like when there is unacked data.
742 * This speeds up eviction of 'dead' connections where the
743 * connection and conntracks internal state are out of sync.
744 */
745 switch (index) {
746 case TCP_RST_SET:
747 case TCP_FIN_SET:
748 break;
749 default:
750 return;
751 }
752
753 if (ct->proto.tcp.last_dir != dir &&
754 (ct->proto.tcp.last_index == TCP_FIN_SET ||
755 ct->proto.tcp.last_index == TCP_RST_SET)) {
756 expires = nf_ct_expires(ct);
757 if (expires < 120 * HZ)
758 return;
759
760 tn = nf_tcp_pernet(net: nf_ct_net(ct));
761 timeouts = nf_ct_timeout_lookup(ct);
762 if (!timeouts)
763 timeouts = tn->timeouts;
764
765 timeout = READ_ONCE(timeouts[TCP_CONNTRACK_UNACK]);
766 if (expires > timeout) {
767 nf_ct_l4proto_log_invalid(skb, ct, state: hook_state,
768 fmt: "packet (index %d, dir %d) response for index %d lower timeout to %u",
769 index, dir, ct->proto.tcp.last_index, timeout);
770
771 WRITE_ONCE(ct->timeout, timeout + nfct_time_stamp);
772 }
773 } else {
774 ct->proto.tcp.last_index = index;
775 ct->proto.tcp.last_dir = dir;
776 }
777}
778
779/* table of valid flag combinations - PUSH, ECE and CWR are always valid */
780static const u8 tcp_valid_flags[(TCPHDR_FIN|TCPHDR_SYN|TCPHDR_RST|TCPHDR_ACK|
781 TCPHDR_URG) + 1] =
782{
783 [TCPHDR_SYN] = 1,
784 [TCPHDR_SYN|TCPHDR_URG] = 1,
785 [TCPHDR_SYN|TCPHDR_ACK] = 1,
786 [TCPHDR_RST] = 1,
787 [TCPHDR_RST|TCPHDR_ACK] = 1,
788 [TCPHDR_FIN|TCPHDR_ACK] = 1,
789 [TCPHDR_FIN|TCPHDR_ACK|TCPHDR_URG] = 1,
790 [TCPHDR_ACK] = 1,
791 [TCPHDR_ACK|TCPHDR_URG] = 1,
792};
793
794static void tcp_error_log(const struct sk_buff *skb,
795 const struct nf_hook_state *state,
796 const char *msg)
797{
798 nf_l4proto_log_invalid(skb, state, IPPROTO_TCP, fmt: "%s", msg);
799}
800
801/* Protect conntrack agaist broken packets. Code taken from ipt_unclean.c. */
802static bool tcp_error(const struct tcphdr *th,
803 struct sk_buff *skb,
804 unsigned int dataoff,
805 const struct nf_hook_state *state)
806{
807 unsigned int tcplen = skb->len - dataoff;
808 u8 tcpflags;
809
810 /* Not whole TCP header or malformed packet */
811 if (th->doff*4 < sizeof(struct tcphdr) || tcplen < th->doff*4) {
812 tcp_error_log(skb, state, msg: "truncated packet");
813 return true;
814 }
815
816 /* Checksum invalid? Ignore.
817 * We skip checking packets on the outgoing path
818 * because the checksum is assumed to be correct.
819 */
820 /* FIXME: Source route IP option packets --RR */
821 if (state->net->ct.sysctl_checksum &&
822 state->hook == NF_INET_PRE_ROUTING &&
823 nf_checksum(skb, hook: state->hook, dataoff, IPPROTO_TCP, family: state->pf)) {
824 tcp_error_log(skb, state, msg: "bad checksum");
825 return true;
826 }
827
828 /* Check TCP flags. */
829 tcpflags = (tcp_flag_byte(th) & ~(TCPHDR_ECE|TCPHDR_CWR|TCPHDR_PSH));
830 if (!tcp_valid_flags[tcpflags]) {
831 tcp_error_log(skb, state, msg: "invalid tcp flag combination");
832 return true;
833 }
834
835 return false;
836}
837
838static noinline bool tcp_new(struct nf_conn *ct, const struct sk_buff *skb,
839 unsigned int dataoff,
840 const struct tcphdr *th,
841 const struct nf_hook_state *state)
842{
843 enum tcp_conntrack new_state;
844 struct net *net = nf_ct_net(ct);
845 const struct nf_tcp_net *tn = nf_tcp_pernet(net);
846
847 /* Don't need lock here: this conntrack not in circulation yet */
848 new_state = tcp_conntracks[0][get_conntrack_index(tcph: th)][TCP_CONNTRACK_NONE];
849
850 /* Invalid: delete conntrack */
851 if (new_state >= TCP_CONNTRACK_MAX) {
852 tcp_error_log(skb, state, msg: "invalid new");
853 return false;
854 }
855
856 if (new_state == TCP_CONNTRACK_SYN_SENT) {
857 memset(s: &ct->proto.tcp, c: 0, n: sizeof(ct->proto.tcp));
858 /* SYN packet */
859 ct->proto.tcp.seen[0].td_end =
860 segment_seq_plus_len(ntohl(th->seq), len: skb->len,
861 dataoff, tcph: th);
862 ct->proto.tcp.seen[0].td_maxwin = ntohs(th->window);
863 if (ct->proto.tcp.seen[0].td_maxwin == 0)
864 ct->proto.tcp.seen[0].td_maxwin = 1;
865 ct->proto.tcp.seen[0].td_maxend =
866 ct->proto.tcp.seen[0].td_end;
867
868 tcp_options(skb, dataoff, tcph: th, state: &ct->proto.tcp.seen[0]);
869 } else if (tn->tcp_loose == 0) {
870 /* Don't try to pick up connections. */
871 return false;
872 } else {
873 memset(s: &ct->proto.tcp, c: 0, n: sizeof(ct->proto.tcp));
874 /*
875 * We are in the middle of a connection,
876 * its history is lost for us.
877 * Let's try to use the data from the packet.
878 */
879 ct->proto.tcp.seen[0].td_end =
880 segment_seq_plus_len(ntohl(th->seq), len: skb->len,
881 dataoff, tcph: th);
882 ct->proto.tcp.seen[0].td_maxwin = ntohs(th->window);
883 if (ct->proto.tcp.seen[0].td_maxwin == 0)
884 ct->proto.tcp.seen[0].td_maxwin = 1;
885 ct->proto.tcp.seen[0].td_maxend =
886 ct->proto.tcp.seen[0].td_end +
887 ct->proto.tcp.seen[0].td_maxwin;
888
889 /* We assume SACK and liberal window checking to handle
890 * window scaling */
891 ct->proto.tcp.seen[0].flags =
892 ct->proto.tcp.seen[1].flags = IP_CT_TCP_FLAG_SACK_PERM |
893 IP_CT_TCP_FLAG_BE_LIBERAL;
894 }
895
896 /* tcp_packet will set them */
897 ct->proto.tcp.last_index = TCP_NONE_SET;
898 return true;
899}
900
901static bool tcp_can_early_drop(const struct nf_conn *ct)
902{
903 switch (ct->proto.tcp.state) {
904 case TCP_CONNTRACK_FIN_WAIT:
905 case TCP_CONNTRACK_LAST_ACK:
906 case TCP_CONNTRACK_TIME_WAIT:
907 case TCP_CONNTRACK_CLOSE:
908 case TCP_CONNTRACK_CLOSE_WAIT:
909 return true;
910 default:
911 break;
912 }
913
914 return false;
915}
916
917void nf_conntrack_tcp_set_closing(struct nf_conn *ct)
918{
919 enum tcp_conntrack old_state;
920 const unsigned int *timeouts;
921 u32 timeout;
922
923 if (!nf_ct_is_confirmed(ct))
924 return;
925
926 spin_lock_bh(lock: &ct->lock);
927 old_state = ct->proto.tcp.state;
928 ct->proto.tcp.state = TCP_CONNTRACK_CLOSE;
929
930 if (old_state == TCP_CONNTRACK_CLOSE ||
931 test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status)) {
932 spin_unlock_bh(lock: &ct->lock);
933 return;
934 }
935
936 timeouts = nf_ct_timeout_lookup(ct);
937 if (!timeouts) {
938 const struct nf_tcp_net *tn;
939
940 tn = nf_tcp_pernet(net: nf_ct_net(ct));
941 timeouts = tn->timeouts;
942 }
943
944 timeout = timeouts[TCP_CONNTRACK_CLOSE];
945 WRITE_ONCE(ct->timeout, timeout + nfct_time_stamp);
946
947 spin_unlock_bh(lock: &ct->lock);
948
949 nf_conntrack_event_cache(event: IPCT_PROTOINFO, ct);
950}
951
952static void nf_ct_tcp_state_reset(struct ip_ct_tcp_state *state)
953{
954 state->td_end = 0;
955 state->td_maxend = 0;
956 state->td_maxwin = 0;
957 state->td_maxack = 0;
958 state->td_scale = 0;
959 state->flags &= IP_CT_TCP_FLAG_BE_LIBERAL;
960}
961
962/* Returns verdict for packet, or -1 for invalid. */
963int nf_conntrack_tcp_packet(struct nf_conn *ct,
964 struct sk_buff *skb,
965 unsigned int dataoff,
966 enum ip_conntrack_info ctinfo,
967 const struct nf_hook_state *state)
968{
969 struct net *net = nf_ct_net(ct);
970 struct nf_tcp_net *tn = nf_tcp_pernet(net);
971 enum tcp_conntrack new_state, old_state;
972 unsigned int index, *timeouts;
973 enum nf_ct_tcp_action res;
974 enum ip_conntrack_dir dir;
975 const struct tcphdr *th;
976 struct tcphdr _tcph;
977 unsigned long timeout;
978
979 th = skb_header_pointer(skb, offset: dataoff, len: sizeof(_tcph), buffer: &_tcph);
980 if (th == NULL)
981 return -NF_ACCEPT;
982
983 if (tcp_error(th, skb, dataoff, state))
984 return -NF_ACCEPT;
985
986 if (!nf_ct_is_confirmed(ct) && !tcp_new(ct, skb, dataoff, th, state))
987 return -NF_ACCEPT;
988
989 spin_lock_bh(lock: &ct->lock);
990 old_state = ct->proto.tcp.state;
991 dir = CTINFO2DIR(ctinfo);
992 index = get_conntrack_index(tcph: th);
993 new_state = tcp_conntracks[dir][index][old_state];
994
995 switch (new_state) {
996 case TCP_CONNTRACK_SYN_SENT:
997 if (old_state < TCP_CONNTRACK_TIME_WAIT)
998 break;
999 /* RFC 1122: "When a connection is closed actively,
1000 * it MUST linger in TIME-WAIT state for a time 2xMSL
1001 * (Maximum Segment Lifetime). However, it MAY accept
1002 * a new SYN from the remote TCP to reopen the connection
1003 * directly from TIME-WAIT state, if..."
1004 * We ignore the conditions because we are in the
1005 * TIME-WAIT state anyway.
1006 *
1007 * Handle aborted connections: we and the server
1008 * think there is an existing connection but the client
1009 * aborts it and starts a new one.
1010 */
1011 if (((ct->proto.tcp.seen[dir].flags
1012 | ct->proto.tcp.seen[!dir].flags)
1013 & IP_CT_TCP_FLAG_CLOSE_INIT)
1014 || (ct->proto.tcp.last_dir == dir
1015 && ct->proto.tcp.last_index == TCP_RST_SET)) {
1016 /* Attempt to reopen a closed/aborted connection.
1017 * Delete this connection and look up again. */
1018 spin_unlock_bh(lock: &ct->lock);
1019
1020 /* Only repeat if we can actually remove the timer.
1021 * Destruction may already be in progress in process
1022 * context and we must give it a chance to terminate.
1023 */
1024 if (nf_ct_kill(ct))
1025 return -NF_REPEAT;
1026 return NF_DROP;
1027 }
1028 fallthrough;
1029 case TCP_CONNTRACK_IGNORE:
1030 /* Ignored packets:
1031 *
1032 * Our connection entry may be out of sync, so ignore
1033 * packets which may signal the real connection between
1034 * the client and the server.
1035 *
1036 * a) SYN in ORIGINAL
1037 * b) SYN/ACK in REPLY
1038 * c) ACK in reply direction after initial SYN in original.
1039 *
1040 * If the ignored packet is invalid, the receiver will send
1041 * a RST we'll catch below.
1042 */
1043 if (index == TCP_SYNACK_SET
1044 && ct->proto.tcp.last_index == TCP_SYN_SET
1045 && ct->proto.tcp.last_dir != dir
1046 && ntohl(th->ack_seq) == ct->proto.tcp.last_end) {
1047 /* b) This SYN/ACK acknowledges a SYN that we earlier
1048 * ignored as invalid. This means that the client and
1049 * the server are both in sync, while the firewall is
1050 * not. We get in sync from the previously annotated
1051 * values.
1052 */
1053 old_state = TCP_CONNTRACK_SYN_SENT;
1054 new_state = TCP_CONNTRACK_SYN_RECV;
1055 ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_end =
1056 ct->proto.tcp.last_end;
1057 ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_maxend =
1058 ct->proto.tcp.last_end;
1059 ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_maxwin =
1060 ct->proto.tcp.last_win == 0 ?
1061 1 : ct->proto.tcp.last_win;
1062 ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_scale =
1063 ct->proto.tcp.last_wscale;
1064 ct->proto.tcp.last_flags &= ~IP_CT_EXP_CHALLENGE_ACK;
1065 ct->proto.tcp.seen[ct->proto.tcp.last_dir].flags =
1066 ct->proto.tcp.last_flags;
1067 nf_ct_tcp_state_reset(state: &ct->proto.tcp.seen[dir]);
1068 break;
1069 }
1070 ct->proto.tcp.last_index = index;
1071 ct->proto.tcp.last_dir = dir;
1072 ct->proto.tcp.last_seq = ntohl(th->seq);
1073 ct->proto.tcp.last_end =
1074 segment_seq_plus_len(ntohl(th->seq), len: skb->len, dataoff, tcph: th);
1075 ct->proto.tcp.last_win = ntohs(th->window);
1076
1077 /* a) This is a SYN in ORIGINAL. The client and the server
1078 * may be in sync but we are not. In that case, we annotate
1079 * the TCP options and let the packet go through. If it is a
1080 * valid SYN packet, the server will reply with a SYN/ACK, and
1081 * then we'll get in sync. Otherwise, the server potentially
1082 * responds with a challenge ACK if implementing RFC5961.
1083 */
1084 if (index == TCP_SYN_SET && dir == IP_CT_DIR_ORIGINAL) {
1085 struct ip_ct_tcp_state seen = {};
1086
1087 ct->proto.tcp.last_flags =
1088 ct->proto.tcp.last_wscale = 0;
1089 tcp_options(skb, dataoff, tcph: th, state: &seen);
1090 if (seen.flags & IP_CT_TCP_FLAG_WINDOW_SCALE) {
1091 ct->proto.tcp.last_flags |=
1092 IP_CT_TCP_FLAG_WINDOW_SCALE;
1093 ct->proto.tcp.last_wscale = seen.td_scale;
1094 }
1095 if (seen.flags & IP_CT_TCP_FLAG_SACK_PERM) {
1096 ct->proto.tcp.last_flags |=
1097 IP_CT_TCP_FLAG_SACK_PERM;
1098 }
1099 /* Mark the potential for RFC5961 challenge ACK,
1100 * this pose a special problem for LAST_ACK state
1101 * as ACK is intrepretated as ACKing last FIN.
1102 */
1103 if (old_state == TCP_CONNTRACK_LAST_ACK)
1104 ct->proto.tcp.last_flags |=
1105 IP_CT_EXP_CHALLENGE_ACK;
1106 }
1107
1108 /* possible challenge ack reply to syn */
1109 if (old_state == TCP_CONNTRACK_SYN_SENT &&
1110 index == TCP_ACK_SET &&
1111 dir == IP_CT_DIR_REPLY)
1112 ct->proto.tcp.last_ack = ntohl(th->ack_seq);
1113
1114 spin_unlock_bh(lock: &ct->lock);
1115 nf_ct_l4proto_log_invalid(skb, ct, state,
1116 fmt: "packet (index %d) in dir %d ignored, state %s",
1117 index, dir,
1118 tcp_conntrack_names[old_state]);
1119 return NF_ACCEPT;
1120 case TCP_CONNTRACK_MAX:
1121 /* Special case for SYN proxy: when the SYN to the server or
1122 * the SYN/ACK from the server is lost, the client may transmit
1123 * a keep-alive packet while in SYN_SENT state. This needs to
1124 * be associated with the original conntrack entry in order to
1125 * generate a new SYN with the correct sequence number.
1126 */
1127 if (nfct_synproxy(ct) && old_state == TCP_CONNTRACK_SYN_SENT &&
1128 index == TCP_ACK_SET && dir == IP_CT_DIR_ORIGINAL &&
1129 ct->proto.tcp.last_dir == IP_CT_DIR_ORIGINAL &&
1130 ct->proto.tcp.seen[dir].td_end - 1 == ntohl(th->seq)) {
1131 pr_debug("nf_ct_tcp: SYN proxy client keep alive\n");
1132 spin_unlock_bh(lock: &ct->lock);
1133 return NF_ACCEPT;
1134 }
1135
1136 /* Invalid packet */
1137 spin_unlock_bh(lock: &ct->lock);
1138 nf_ct_l4proto_log_invalid(skb, ct, state,
1139 fmt: "packet (index %d) in dir %d invalid, state %s",
1140 index, dir,
1141 tcp_conntrack_names[old_state]);
1142 return -NF_ACCEPT;
1143 case TCP_CONNTRACK_TIME_WAIT:
1144 /* RFC5961 compliance cause stack to send "challenge-ACK"
1145 * e.g. in response to spurious SYNs. Conntrack MUST
1146 * not believe this ACK is acking last FIN.
1147 */
1148 if (old_state == TCP_CONNTRACK_LAST_ACK &&
1149 index == TCP_ACK_SET &&
1150 ct->proto.tcp.last_dir != dir &&
1151 ct->proto.tcp.last_index == TCP_SYN_SET &&
1152 (ct->proto.tcp.last_flags & IP_CT_EXP_CHALLENGE_ACK)) {
1153 /* Detected RFC5961 challenge ACK */
1154 ct->proto.tcp.last_flags &= ~IP_CT_EXP_CHALLENGE_ACK;
1155 spin_unlock_bh(lock: &ct->lock);
1156 nf_ct_l4proto_log_invalid(skb, ct, state, fmt: "challenge-ack ignored");
1157 return NF_ACCEPT; /* Don't change state */
1158 }
1159 break;
1160 case TCP_CONNTRACK_SYN_SENT2:
1161 /* tcp_conntracks table is not smart enough to handle
1162 * simultaneous open.
1163 */
1164 ct->proto.tcp.last_flags |= IP_CT_TCP_SIMULTANEOUS_OPEN;
1165 break;
1166 case TCP_CONNTRACK_SYN_RECV:
1167 if (dir == IP_CT_DIR_REPLY && index == TCP_ACK_SET &&
1168 ct->proto.tcp.last_flags & IP_CT_TCP_SIMULTANEOUS_OPEN)
1169 new_state = TCP_CONNTRACK_ESTABLISHED;
1170 break;
1171 case TCP_CONNTRACK_CLOSE:
1172 if (index != TCP_RST_SET)
1173 break;
1174
1175 /* If we are closing, tuple might have been re-used already.
1176 * last_index, last_ack, and all other ct fields used for
1177 * sequence/window validation are outdated in that case.
1178 *
1179 * As the conntrack can already be expired by GC under pressure,
1180 * just skip validation checks.
1181 */
1182 if (tcp_can_early_drop(ct))
1183 goto in_window;
1184
1185 /* td_maxack might be outdated if we let a SYN through earlier */
1186 if ((ct->proto.tcp.seen[!dir].flags & IP_CT_TCP_FLAG_MAXACK_SET) &&
1187 ct->proto.tcp.last_index != TCP_SYN_SET) {
1188 u32 seq = ntohl(th->seq);
1189
1190 /* If we are not in established state and SEQ=0 this is most
1191 * likely an answer to a SYN we let go through above (last_index
1192 * can be updated due to out-of-order ACKs).
1193 */
1194 if (seq == 0 && !nf_conntrack_tcp_established(ct))
1195 break;
1196
1197 if (before(seq1: seq, seq2: ct->proto.tcp.seen[!dir].td_maxack) &&
1198 !tn->tcp_ignore_invalid_rst) {
1199 /* Invalid RST */
1200 spin_unlock_bh(lock: &ct->lock);
1201 nf_ct_l4proto_log_invalid(skb, ct, state, fmt: "invalid rst");
1202 return -NF_ACCEPT;
1203 }
1204
1205 if (!nf_conntrack_tcp_established(ct) ||
1206 seq == ct->proto.tcp.seen[!dir].td_maxack)
1207 break;
1208
1209 /* Check if rst is part of train, such as
1210 * foo:80 > bar:4379: P, 235946583:235946602(19) ack 42
1211 * foo:80 > bar:4379: R, 235946602:235946602(0) ack 42
1212 */
1213 if (ct->proto.tcp.last_index == TCP_ACK_SET &&
1214 ct->proto.tcp.last_dir == dir &&
1215 seq == ct->proto.tcp.last_end)
1216 break;
1217
1218 /* ... RST sequence number doesn't match exactly, keep
1219 * established state to allow a possible challenge ACK.
1220 */
1221 new_state = old_state;
1222 }
1223 if (((test_bit(IPS_SEEN_REPLY_BIT, &ct->status)
1224 && ct->proto.tcp.last_index == TCP_SYN_SET)
1225 || (!test_bit(IPS_ASSURED_BIT, &ct->status)
1226 && ct->proto.tcp.last_index == TCP_ACK_SET))
1227 && ntohl(th->ack_seq) == ct->proto.tcp.last_end) {
1228 /* RST sent to invalid SYN or ACK we had let through
1229 * at a) and c) above:
1230 *
1231 * a) SYN was in window then
1232 * c) we hold a half-open connection.
1233 *
1234 * Delete our connection entry.
1235 * We skip window checking, because packet might ACK
1236 * segments we ignored. */
1237 goto in_window;
1238 }
1239
1240 /* Reset in response to a challenge-ack we let through earlier */
1241 if (old_state == TCP_CONNTRACK_SYN_SENT &&
1242 ct->proto.tcp.last_index == TCP_ACK_SET &&
1243 ct->proto.tcp.last_dir == IP_CT_DIR_REPLY &&
1244 ntohl(th->seq) == ct->proto.tcp.last_ack)
1245 goto in_window;
1246
1247 break;
1248 default:
1249 /* Keep compilers happy. */
1250 break;
1251 }
1252
1253 res = tcp_in_window(ct, dir, index,
1254 skb, dataoff, tcph: th, hook_state: state);
1255 switch (res) {
1256 case NFCT_TCP_IGNORE:
1257 spin_unlock_bh(lock: &ct->lock);
1258 return NF_ACCEPT;
1259 case NFCT_TCP_INVALID:
1260 nf_tcp_handle_invalid(ct, dir, index, skb, hook_state: state);
1261 spin_unlock_bh(lock: &ct->lock);
1262 return -NF_ACCEPT;
1263 case NFCT_TCP_ACCEPT:
1264 break;
1265 }
1266 in_window:
1267 /* From now on we have got in-window packets */
1268 ct->proto.tcp.last_index = index;
1269 ct->proto.tcp.last_dir = dir;
1270
1271 ct->proto.tcp.state = new_state;
1272 if (old_state != new_state
1273 && new_state == TCP_CONNTRACK_FIN_WAIT)
1274 ct->proto.tcp.seen[dir].flags |= IP_CT_TCP_FLAG_CLOSE_INIT;
1275
1276 timeouts = nf_ct_timeout_lookup(ct);
1277 if (!timeouts)
1278 timeouts = tn->timeouts;
1279
1280 if (ct->proto.tcp.retrans >= tn->tcp_max_retrans &&
1281 timeouts[new_state] > timeouts[TCP_CONNTRACK_RETRANS])
1282 timeout = timeouts[TCP_CONNTRACK_RETRANS];
1283 else if (unlikely(index == TCP_RST_SET))
1284 timeout = timeouts[TCP_CONNTRACK_CLOSE];
1285 else if ((ct->proto.tcp.seen[0].flags | ct->proto.tcp.seen[1].flags) &
1286 IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED &&
1287 timeouts[new_state] > timeouts[TCP_CONNTRACK_UNACK])
1288 timeout = timeouts[TCP_CONNTRACK_UNACK];
1289 else if (ct->proto.tcp.last_win == 0 &&
1290 timeouts[new_state] > timeouts[TCP_CONNTRACK_RETRANS])
1291 timeout = timeouts[TCP_CONNTRACK_RETRANS];
1292 else
1293 timeout = timeouts[new_state];
1294 spin_unlock_bh(lock: &ct->lock);
1295
1296 if (new_state != old_state)
1297 nf_conntrack_event_cache(event: IPCT_PROTOINFO, ct);
1298
1299 if (!test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
1300 /* If only reply is a RST, we can consider ourselves not to
1301 have an established connection: this is a fairly common
1302 problem case, so we can delete the conntrack
1303 immediately. --RR */
1304 if (th->rst) {
1305 nf_ct_kill_acct(ct, ctinfo, skb);
1306 return NF_ACCEPT;
1307 }
1308
1309 if (index == TCP_SYN_SET && old_state == TCP_CONNTRACK_SYN_SENT) {
1310 /* do not renew timeout on SYN retransmit.
1311 *
1312 * Else port reuse by client or NAT middlebox can keep
1313 * entry alive indefinitely (including nat info).
1314 */
1315 return NF_ACCEPT;
1316 }
1317
1318 /* ESTABLISHED without SEEN_REPLY, i.e. mid-connection
1319 * pickup with loose=1. Avoid large ESTABLISHED timeout.
1320 */
1321 if (new_state == TCP_CONNTRACK_ESTABLISHED &&
1322 timeout > timeouts[TCP_CONNTRACK_UNACK])
1323 timeout = timeouts[TCP_CONNTRACK_UNACK];
1324 } else if (!test_bit(IPS_ASSURED_BIT, &ct->status)
1325 && (old_state == TCP_CONNTRACK_SYN_RECV
1326 || old_state == TCP_CONNTRACK_ESTABLISHED)
1327 && new_state == TCP_CONNTRACK_ESTABLISHED) {
1328 /* Set ASSURED if we see valid ack in ESTABLISHED
1329 after SYN_RECV or a valid answer for a picked up
1330 connection. */
1331 set_bit(nr: IPS_ASSURED_BIT, addr: &ct->status);
1332 nf_conntrack_event_cache(event: IPCT_ASSURED, ct);
1333 }
1334 nf_ct_refresh_acct(ct, ctinfo, skb, extra_jiffies: timeout);
1335
1336 return NF_ACCEPT;
1337}
1338
1339#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
1340
1341#include <linux/netfilter/nfnetlink.h>
1342#include <linux/netfilter/nfnetlink_conntrack.h>
1343
1344static int tcp_to_nlattr(struct sk_buff *skb, struct nlattr *nla,
1345 struct nf_conn *ct, bool destroy)
1346{
1347 struct nlattr *nest_parms;
1348 struct nf_ct_tcp_flags tmp = {};
1349
1350 spin_lock_bh(lock: &ct->lock);
1351 nest_parms = nla_nest_start(skb, attrtype: CTA_PROTOINFO_TCP);
1352 if (!nest_parms)
1353 goto nla_put_failure;
1354
1355 if (nla_put_u8(skb, attrtype: CTA_PROTOINFO_TCP_STATE, value: ct->proto.tcp.state))
1356 goto nla_put_failure;
1357
1358 if (destroy)
1359 goto skip_state;
1360
1361 if (nla_put_u8(skb, attrtype: CTA_PROTOINFO_TCP_WSCALE_ORIGINAL,
1362 value: ct->proto.tcp.seen[0].td_scale) ||
1363 nla_put_u8(skb, attrtype: CTA_PROTOINFO_TCP_WSCALE_REPLY,
1364 value: ct->proto.tcp.seen[1].td_scale))
1365 goto nla_put_failure;
1366
1367 tmp.flags = ct->proto.tcp.seen[0].flags;
1368 if (nla_put(skb, attrtype: CTA_PROTOINFO_TCP_FLAGS_ORIGINAL,
1369 attrlen: sizeof(struct nf_ct_tcp_flags), data: &tmp))
1370 goto nla_put_failure;
1371
1372 tmp.flags = ct->proto.tcp.seen[1].flags;
1373 if (nla_put(skb, attrtype: CTA_PROTOINFO_TCP_FLAGS_REPLY,
1374 attrlen: sizeof(struct nf_ct_tcp_flags), data: &tmp))
1375 goto nla_put_failure;
1376skip_state:
1377 spin_unlock_bh(lock: &ct->lock);
1378 nla_nest_end(skb, start: nest_parms);
1379
1380 return 0;
1381
1382nla_put_failure:
1383 spin_unlock_bh(lock: &ct->lock);
1384 return -1;
1385}
1386
1387static const struct nla_policy tcp_nla_policy[CTA_PROTOINFO_TCP_MAX+1] = {
1388 [CTA_PROTOINFO_TCP_STATE] = { .type = NLA_U8 },
1389 [CTA_PROTOINFO_TCP_WSCALE_ORIGINAL] = { .type = NLA_U8 },
1390 [CTA_PROTOINFO_TCP_WSCALE_REPLY] = { .type = NLA_U8 },
1391 [CTA_PROTOINFO_TCP_FLAGS_ORIGINAL] = { .len = sizeof(struct nf_ct_tcp_flags) },
1392 [CTA_PROTOINFO_TCP_FLAGS_REPLY] = { .len = sizeof(struct nf_ct_tcp_flags) },
1393};
1394
1395#define TCP_NLATTR_SIZE ( \
1396 NLA_ALIGN(NLA_HDRLEN + 1) + \
1397 NLA_ALIGN(NLA_HDRLEN + 1) + \
1398 NLA_ALIGN(NLA_HDRLEN + sizeof(struct nf_ct_tcp_flags)) + \
1399 NLA_ALIGN(NLA_HDRLEN + sizeof(struct nf_ct_tcp_flags)))
1400
1401static int nlattr_to_tcp(struct nlattr *cda[], struct nf_conn *ct)
1402{
1403 struct nlattr *pattr = cda[CTA_PROTOINFO_TCP];
1404 struct nlattr *tb[CTA_PROTOINFO_TCP_MAX+1];
1405 int err;
1406
1407 /* updates could not contain anything about the private
1408 * protocol info, in that case skip the parsing */
1409 if (!pattr)
1410 return 0;
1411
1412 err = nla_parse_nested_deprecated(tb, CTA_PROTOINFO_TCP_MAX, nla: pattr,
1413 policy: tcp_nla_policy, NULL);
1414 if (err < 0)
1415 return err;
1416
1417 if (tb[CTA_PROTOINFO_TCP_STATE] &&
1418 nla_get_u8(nla: tb[CTA_PROTOINFO_TCP_STATE]) >= TCP_CONNTRACK_MAX)
1419 return -EINVAL;
1420
1421 spin_lock_bh(lock: &ct->lock);
1422 if (tb[CTA_PROTOINFO_TCP_STATE])
1423 ct->proto.tcp.state = nla_get_u8(nla: tb[CTA_PROTOINFO_TCP_STATE]);
1424
1425 if (tb[CTA_PROTOINFO_TCP_FLAGS_ORIGINAL]) {
1426 struct nf_ct_tcp_flags *attr =
1427 nla_data(nla: tb[CTA_PROTOINFO_TCP_FLAGS_ORIGINAL]);
1428 ct->proto.tcp.seen[0].flags &= ~attr->mask;
1429 ct->proto.tcp.seen[0].flags |= attr->flags & attr->mask;
1430 }
1431
1432 if (tb[CTA_PROTOINFO_TCP_FLAGS_REPLY]) {
1433 struct nf_ct_tcp_flags *attr =
1434 nla_data(nla: tb[CTA_PROTOINFO_TCP_FLAGS_REPLY]);
1435 ct->proto.tcp.seen[1].flags &= ~attr->mask;
1436 ct->proto.tcp.seen[1].flags |= attr->flags & attr->mask;
1437 }
1438
1439 if (tb[CTA_PROTOINFO_TCP_WSCALE_ORIGINAL] &&
1440 tb[CTA_PROTOINFO_TCP_WSCALE_REPLY] &&
1441 ct->proto.tcp.seen[0].flags & IP_CT_TCP_FLAG_WINDOW_SCALE &&
1442 ct->proto.tcp.seen[1].flags & IP_CT_TCP_FLAG_WINDOW_SCALE) {
1443 ct->proto.tcp.seen[0].td_scale =
1444 nla_get_u8(nla: tb[CTA_PROTOINFO_TCP_WSCALE_ORIGINAL]);
1445 ct->proto.tcp.seen[1].td_scale =
1446 nla_get_u8(nla: tb[CTA_PROTOINFO_TCP_WSCALE_REPLY]);
1447 }
1448 spin_unlock_bh(lock: &ct->lock);
1449
1450 return 0;
1451}
1452
1453static unsigned int tcp_nlattr_tuple_size(void)
1454{
1455 static unsigned int size __read_mostly;
1456
1457 if (!size)
1458 size = nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1);
1459
1460 return size;
1461}
1462#endif
1463
1464#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
1465
1466#include <linux/netfilter/nfnetlink.h>
1467#include <linux/netfilter/nfnetlink_cttimeout.h>
1468
1469static int tcp_timeout_nlattr_to_obj(struct nlattr *tb[],
1470 struct net *net, void *data)
1471{
1472 struct nf_tcp_net *tn = nf_tcp_pernet(net);
1473 unsigned int *timeouts = data;
1474 int i;
1475
1476 if (!timeouts)
1477 timeouts = tn->timeouts;
1478 /* set default TCP timeouts. */
1479 for (i=0; i<TCP_CONNTRACK_TIMEOUT_MAX; i++)
1480 timeouts[i] = tn->timeouts[i];
1481
1482 if (tb[CTA_TIMEOUT_TCP_SYN_SENT]) {
1483 timeouts[TCP_CONNTRACK_SYN_SENT] =
1484 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_SYN_SENT]))*HZ;
1485 }
1486
1487 if (tb[CTA_TIMEOUT_TCP_SYN_RECV]) {
1488 timeouts[TCP_CONNTRACK_SYN_RECV] =
1489 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_SYN_RECV]))*HZ;
1490 }
1491 if (tb[CTA_TIMEOUT_TCP_ESTABLISHED]) {
1492 timeouts[TCP_CONNTRACK_ESTABLISHED] =
1493 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_ESTABLISHED]))*HZ;
1494 }
1495 if (tb[CTA_TIMEOUT_TCP_FIN_WAIT]) {
1496 timeouts[TCP_CONNTRACK_FIN_WAIT] =
1497 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_FIN_WAIT]))*HZ;
1498 }
1499 if (tb[CTA_TIMEOUT_TCP_CLOSE_WAIT]) {
1500 timeouts[TCP_CONNTRACK_CLOSE_WAIT] =
1501 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_CLOSE_WAIT]))*HZ;
1502 }
1503 if (tb[CTA_TIMEOUT_TCP_LAST_ACK]) {
1504 timeouts[TCP_CONNTRACK_LAST_ACK] =
1505 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_LAST_ACK]))*HZ;
1506 }
1507 if (tb[CTA_TIMEOUT_TCP_TIME_WAIT]) {
1508 timeouts[TCP_CONNTRACK_TIME_WAIT] =
1509 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_TIME_WAIT]))*HZ;
1510 }
1511 if (tb[CTA_TIMEOUT_TCP_CLOSE]) {
1512 timeouts[TCP_CONNTRACK_CLOSE] =
1513 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_CLOSE]))*HZ;
1514 }
1515 if (tb[CTA_TIMEOUT_TCP_SYN_SENT2]) {
1516 timeouts[TCP_CONNTRACK_SYN_SENT2] =
1517 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_SYN_SENT2]))*HZ;
1518 }
1519 if (tb[CTA_TIMEOUT_TCP_RETRANS]) {
1520 timeouts[TCP_CONNTRACK_RETRANS] =
1521 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_RETRANS]))*HZ;
1522 }
1523 if (tb[CTA_TIMEOUT_TCP_UNACK]) {
1524 timeouts[TCP_CONNTRACK_UNACK] =
1525 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_UNACK]))*HZ;
1526 }
1527
1528 timeouts[CTA_TIMEOUT_TCP_UNSPEC] = timeouts[CTA_TIMEOUT_TCP_SYN_SENT];
1529 return 0;
1530}
1531
1532static int
1533tcp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
1534{
1535 const unsigned int *timeouts = data;
1536
1537 if (nla_put_be32(skb, CTA_TIMEOUT_TCP_SYN_SENT,
1538 htonl(timeouts[TCP_CONNTRACK_SYN_SENT] / HZ)) ||
1539 nla_put_be32(skb, CTA_TIMEOUT_TCP_SYN_RECV,
1540 htonl(timeouts[TCP_CONNTRACK_SYN_RECV] / HZ)) ||
1541 nla_put_be32(skb, CTA_TIMEOUT_TCP_ESTABLISHED,
1542 htonl(timeouts[TCP_CONNTRACK_ESTABLISHED] / HZ)) ||
1543 nla_put_be32(skb, CTA_TIMEOUT_TCP_FIN_WAIT,
1544 htonl(timeouts[TCP_CONNTRACK_FIN_WAIT] / HZ)) ||
1545 nla_put_be32(skb, CTA_TIMEOUT_TCP_CLOSE_WAIT,
1546 htonl(timeouts[TCP_CONNTRACK_CLOSE_WAIT] / HZ)) ||
1547 nla_put_be32(skb, CTA_TIMEOUT_TCP_LAST_ACK,
1548 htonl(timeouts[TCP_CONNTRACK_LAST_ACK] / HZ)) ||
1549 nla_put_be32(skb, CTA_TIMEOUT_TCP_TIME_WAIT,
1550 htonl(timeouts[TCP_CONNTRACK_TIME_WAIT] / HZ)) ||
1551 nla_put_be32(skb, CTA_TIMEOUT_TCP_CLOSE,
1552 htonl(timeouts[TCP_CONNTRACK_CLOSE] / HZ)) ||
1553 nla_put_be32(skb, CTA_TIMEOUT_TCP_SYN_SENT2,
1554 htonl(timeouts[TCP_CONNTRACK_SYN_SENT2] / HZ)) ||
1555 nla_put_be32(skb, CTA_TIMEOUT_TCP_RETRANS,
1556 htonl(timeouts[TCP_CONNTRACK_RETRANS] / HZ)) ||
1557 nla_put_be32(skb, CTA_TIMEOUT_TCP_UNACK,
1558 htonl(timeouts[TCP_CONNTRACK_UNACK] / HZ)))
1559 goto nla_put_failure;
1560 return 0;
1561
1562nla_put_failure:
1563 return -ENOSPC;
1564}
1565
1566static const struct nla_policy tcp_timeout_nla_policy[CTA_TIMEOUT_TCP_MAX+1] = {
1567 [CTA_TIMEOUT_TCP_SYN_SENT] = { .type = NLA_U32 },
1568 [CTA_TIMEOUT_TCP_SYN_RECV] = { .type = NLA_U32 },
1569 [CTA_TIMEOUT_TCP_ESTABLISHED] = { .type = NLA_U32 },
1570 [CTA_TIMEOUT_TCP_FIN_WAIT] = { .type = NLA_U32 },
1571 [CTA_TIMEOUT_TCP_CLOSE_WAIT] = { .type = NLA_U32 },
1572 [CTA_TIMEOUT_TCP_LAST_ACK] = { .type = NLA_U32 },
1573 [CTA_TIMEOUT_TCP_TIME_WAIT] = { .type = NLA_U32 },
1574 [CTA_TIMEOUT_TCP_CLOSE] = { .type = NLA_U32 },
1575 [CTA_TIMEOUT_TCP_SYN_SENT2] = { .type = NLA_U32 },
1576 [CTA_TIMEOUT_TCP_RETRANS] = { .type = NLA_U32 },
1577 [CTA_TIMEOUT_TCP_UNACK] = { .type = NLA_U32 },
1578};
1579#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
1580
1581void nf_conntrack_tcp_init_net(struct net *net)
1582{
1583 struct nf_tcp_net *tn = nf_tcp_pernet(net);
1584 int i;
1585
1586 for (i = 0; i < TCP_CONNTRACK_TIMEOUT_MAX; i++)
1587 tn->timeouts[i] = tcp_timeouts[i];
1588
1589 /* timeouts[0] is unused, make it same as SYN_SENT so
1590 * ->timeouts[0] contains 'new' timeout, like udp or icmp.
1591 */
1592 tn->timeouts[0] = tcp_timeouts[TCP_CONNTRACK_SYN_SENT];
1593
1594 /* If it is set to zero, we disable picking up already established
1595 * connections.
1596 */
1597 tn->tcp_loose = 1;
1598
1599 /* "Be conservative in what you do,
1600 * be liberal in what you accept from others."
1601 * If it's non-zero, we mark only out of window RST segments as INVALID.
1602 */
1603 tn->tcp_be_liberal = 0;
1604
1605 /* If it's non-zero, we turn off RST sequence number check */
1606 tn->tcp_ignore_invalid_rst = 0;
1607
1608 /* Max number of the retransmitted packets without receiving an (acceptable)
1609 * ACK from the destination. If this number is reached, a shorter timer
1610 * will be started.
1611 */
1612 tn->tcp_max_retrans = 3;
1613
1614#if IS_ENABLED(CONFIG_NF_FLOW_TABLE)
1615 tn->offload_timeout = 30 * HZ;
1616#endif
1617}
1618
1619const struct nf_conntrack_l4proto nf_conntrack_l4proto_tcp =
1620{
1621 .l4proto = IPPROTO_TCP,
1622#ifdef CONFIG_NF_CONNTRACK_PROCFS
1623 .print_conntrack = tcp_print_conntrack,
1624#endif
1625 .can_early_drop = tcp_can_early_drop,
1626#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
1627 .to_nlattr = tcp_to_nlattr,
1628 .from_nlattr = nlattr_to_tcp,
1629 .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
1630 .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
1631 .nlattr_tuple_size = tcp_nlattr_tuple_size,
1632 .nlattr_size = TCP_NLATTR_SIZE,
1633 .nla_policy = nf_ct_port_nla_policy,
1634#endif
1635#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
1636 .ctnl_timeout = {
1637 .nlattr_to_obj = tcp_timeout_nlattr_to_obj,
1638 .obj_to_nlattr = tcp_timeout_obj_to_nlattr,
1639 .nlattr_max = CTA_TIMEOUT_TCP_MAX,
1640 .obj_size = sizeof(unsigned int) *
1641 TCP_CONNTRACK_TIMEOUT_MAX,
1642 .nla_policy = tcp_timeout_nla_policy,
1643 },
1644#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
1645};
1646