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[deliverable/linux.git] / net / ipv4 / netfilter / ip_conntrack_proto_tcp.c
1 /* (C) 1999-2001 Paul `Rusty' Russell
2 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 * Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>:
9 * - Real stateful connection tracking
10 * - Modified state transitions table
11 * - Window scaling support added
12 * - SACK support added
13 *
14 * Willy Tarreau:
15 * - State table bugfixes
16 * - More robust state changes
17 * - Tuning timer parameters
18 *
19 * version 2.2
20 */
21
22 #include <linux/types.h>
23 #include <linux/sched.h>
24 #include <linux/timer.h>
25 #include <linux/netfilter.h>
26 #include <linux/module.h>
27 #include <linux/in.h>
28 #include <linux/ip.h>
29 #include <linux/tcp.h>
30 #include <linux/spinlock.h>
31
32 #include <net/tcp.h>
33
34 #include <linux/netfilter_ipv4.h>
35 #include <linux/netfilter_ipv4/ip_conntrack.h>
36 #include <linux/netfilter_ipv4/ip_conntrack_protocol.h>
37
38 #if 0
39 #define DEBUGP printk
40 #define DEBUGP_VARS
41 #else
42 #define DEBUGP(format, args...)
43 #endif
44
45 /* Protects conntrack->proto.tcp */
46 static DEFINE_RWLOCK(tcp_lock);
47
48 /* "Be conservative in what you do,
49 be liberal in what you accept from others."
50 If it's non-zero, we mark only out of window RST segments as INVALID. */
51 int ip_ct_tcp_be_liberal = 0;
52
53 /* When connection is picked up from the middle, how many packets are required
54 to pass in each direction when we assume we are in sync - if any side uses
55 window scaling, we lost the game.
56 If it is set to zero, we disable picking up already established
57 connections. */
58 int ip_ct_tcp_loose = 3;
59
60 /* Max number of the retransmitted packets without receiving an (acceptable)
61 ACK from the destination. If this number is reached, a shorter timer
62 will be started. */
63 int ip_ct_tcp_max_retrans = 3;
64
65 /* FIXME: Examine ipfilter's timeouts and conntrack transitions more
66 closely. They're more complex. --RR */
67
68 static const char *tcp_conntrack_names[] = {
69 "NONE",
70 "SYN_SENT",
71 "SYN_RECV",
72 "ESTABLISHED",
73 "FIN_WAIT",
74 "CLOSE_WAIT",
75 "LAST_ACK",
76 "TIME_WAIT",
77 "CLOSE",
78 "LISTEN"
79 };
80
81 #define SECS * HZ
82 #define MINS * 60 SECS
83 #define HOURS * 60 MINS
84 #define DAYS * 24 HOURS
85
86 unsigned int ip_ct_tcp_timeout_syn_sent = 2 MINS;
87 unsigned int ip_ct_tcp_timeout_syn_recv = 60 SECS;
88 unsigned int ip_ct_tcp_timeout_established = 5 DAYS;
89 unsigned int ip_ct_tcp_timeout_fin_wait = 2 MINS;
90 unsigned int ip_ct_tcp_timeout_close_wait = 60 SECS;
91 unsigned int ip_ct_tcp_timeout_last_ack = 30 SECS;
92 unsigned int ip_ct_tcp_timeout_time_wait = 2 MINS;
93 unsigned int ip_ct_tcp_timeout_close = 10 SECS;
94
95 /* RFC1122 says the R2 limit should be at least 100 seconds.
96 Linux uses 15 packets as limit, which corresponds
97 to ~13-30min depending on RTO. */
98 unsigned int ip_ct_tcp_timeout_max_retrans = 5 MINS;
99
100 static const unsigned int * tcp_timeouts[]
101 = { NULL, /* TCP_CONNTRACK_NONE */
102 &ip_ct_tcp_timeout_syn_sent, /* TCP_CONNTRACK_SYN_SENT, */
103 &ip_ct_tcp_timeout_syn_recv, /* TCP_CONNTRACK_SYN_RECV, */
104 &ip_ct_tcp_timeout_established, /* TCP_CONNTRACK_ESTABLISHED, */
105 &ip_ct_tcp_timeout_fin_wait, /* TCP_CONNTRACK_FIN_WAIT, */
106 &ip_ct_tcp_timeout_close_wait, /* TCP_CONNTRACK_CLOSE_WAIT, */
107 &ip_ct_tcp_timeout_last_ack, /* TCP_CONNTRACK_LAST_ACK, */
108 &ip_ct_tcp_timeout_time_wait, /* TCP_CONNTRACK_TIME_WAIT, */
109 &ip_ct_tcp_timeout_close, /* TCP_CONNTRACK_CLOSE, */
110 NULL, /* TCP_CONNTRACK_LISTEN */
111 };
112
113 #define sNO TCP_CONNTRACK_NONE
114 #define sSS TCP_CONNTRACK_SYN_SENT
115 #define sSR TCP_CONNTRACK_SYN_RECV
116 #define sES TCP_CONNTRACK_ESTABLISHED
117 #define sFW TCP_CONNTRACK_FIN_WAIT
118 #define sCW TCP_CONNTRACK_CLOSE_WAIT
119 #define sLA TCP_CONNTRACK_LAST_ACK
120 #define sTW TCP_CONNTRACK_TIME_WAIT
121 #define sCL TCP_CONNTRACK_CLOSE
122 #define sLI TCP_CONNTRACK_LISTEN
123 #define sIV TCP_CONNTRACK_MAX
124 #define sIG TCP_CONNTRACK_IGNORE
125
126 /* What TCP flags are set from RST/SYN/FIN/ACK. */
127 enum tcp_bit_set {
128 TCP_SYN_SET,
129 TCP_SYNACK_SET,
130 TCP_FIN_SET,
131 TCP_ACK_SET,
132 TCP_RST_SET,
133 TCP_NONE_SET,
134 };
135
136 /*
137 * The TCP state transition table needs a few words...
138 *
139 * We are the man in the middle. All the packets go through us
140 * but might get lost in transit to the destination.
141 * It is assumed that the destinations can't receive segments
142 * we haven't seen.
143 *
144 * The checked segment is in window, but our windows are *not*
145 * equivalent with the ones of the sender/receiver. We always
146 * try to guess the state of the current sender.
147 *
148 * The meaning of the states are:
149 *
150 * NONE: initial state
151 * SYN_SENT: SYN-only packet seen
152 * SYN_RECV: SYN-ACK packet seen
153 * ESTABLISHED: ACK packet seen
154 * FIN_WAIT: FIN packet seen
155 * CLOSE_WAIT: ACK seen (after FIN)
156 * LAST_ACK: FIN seen (after FIN)
157 * TIME_WAIT: last ACK seen
158 * CLOSE: closed connection
159 *
160 * LISTEN state is not used.
161 *
162 * Packets marked as IGNORED (sIG):
163 * if they may be either invalid or valid
164 * and the receiver may send back a connection
165 * closing RST or a SYN/ACK.
166 *
167 * Packets marked as INVALID (sIV):
168 * if they are invalid
169 * or we do not support the request (simultaneous open)
170 */
171 static const enum tcp_conntrack tcp_conntracks[2][6][TCP_CONNTRACK_MAX] = {
172 {
173 /* ORIGINAL */
174 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
175 /*syn*/ { sSS, sSS, sIG, sIG, sIG, sIG, sIG, sSS, sSS, sIV },
176 /*
177 * sNO -> sSS Initialize a new connection
178 * sSS -> sSS Retransmitted SYN
179 * sSR -> sIG Late retransmitted SYN?
180 * sES -> sIG Error: SYNs in window outside the SYN_SENT state
181 * are errors. Receiver will reply with RST
182 * and close the connection.
183 * Or we are not in sync and hold a dead connection.
184 * sFW -> sIG
185 * sCW -> sIG
186 * sLA -> sIG
187 * sTW -> sSS Reopened connection (RFC 1122).
188 * sCL -> sSS
189 */
190 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
191 /*synack*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV },
192 /*
193 * A SYN/ACK from the client is always invalid:
194 * - either it tries to set up a simultaneous open, which is
195 * not supported;
196 * - or the firewall has just been inserted between the two hosts
197 * during the session set-up. The SYN will be retransmitted
198 * by the true client (or it'll time out).
199 */
200 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
201 /*fin*/ { sIV, sIV, sFW, sFW, sLA, sLA, sLA, sTW, sCL, sIV },
202 /*
203 * sNO -> sIV Too late and no reason to do anything...
204 * sSS -> sIV Client migth not send FIN in this state:
205 * we enforce waiting for a SYN/ACK reply first.
206 * sSR -> sFW Close started.
207 * sES -> sFW
208 * sFW -> sLA FIN seen in both directions, waiting for
209 * the last ACK.
210 * Migth be a retransmitted FIN as well...
211 * sCW -> sLA
212 * sLA -> sLA Retransmitted FIN. Remain in the same state.
213 * sTW -> sTW
214 * sCL -> sCL
215 */
216 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
217 /*ack*/ { sES, sIV, sES, sES, sCW, sCW, sTW, sTW, sCL, sIV },
218 /*
219 * sNO -> sES Assumed.
220 * sSS -> sIV ACK is invalid: we haven't seen a SYN/ACK yet.
221 * sSR -> sES Established state is reached.
222 * sES -> sES :-)
223 * sFW -> sCW Normal close request answered by ACK.
224 * sCW -> sCW
225 * sLA -> sTW Last ACK detected.
226 * sTW -> sTW Retransmitted last ACK. Remain in the same state.
227 * sCL -> sCL
228 */
229 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
230 /*rst*/ { sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sIV },
231 /*none*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV }
232 },
233 {
234 /* REPLY */
235 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
236 /*syn*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV },
237 /*
238 * sNO -> sIV Never reached.
239 * sSS -> sIV Simultaneous open, not supported
240 * sSR -> sIV Simultaneous open, not supported.
241 * sES -> sIV Server may not initiate a connection.
242 * sFW -> sIV
243 * sCW -> sIV
244 * sLA -> sIV
245 * sTW -> sIV Reopened connection, but server may not do it.
246 * sCL -> sIV
247 */
248 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
249 /*synack*/ { sIV, sSR, sSR, sIG, sIG, sIG, sIG, sIG, sIG, sIV },
250 /*
251 * sSS -> sSR Standard open.
252 * sSR -> sSR Retransmitted SYN/ACK.
253 * sES -> sIG Late retransmitted SYN/ACK?
254 * sFW -> sIG Might be SYN/ACK answering ignored SYN
255 * sCW -> sIG
256 * sLA -> sIG
257 * sTW -> sIG
258 * sCL -> sIG
259 */
260 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
261 /*fin*/ { sIV, sIV, sFW, sFW, sLA, sLA, sLA, sTW, sCL, sIV },
262 /*
263 * sSS -> sIV Server might not send FIN in this state.
264 * sSR -> sFW Close started.
265 * sES -> sFW
266 * sFW -> sLA FIN seen in both directions.
267 * sCW -> sLA
268 * sLA -> sLA Retransmitted FIN.
269 * sTW -> sTW
270 * sCL -> sCL
271 */
272 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
273 /*ack*/ { sIV, sIG, sSR, sES, sCW, sCW, sTW, sTW, sCL, sIV },
274 /*
275 * sSS -> sIG Might be a half-open connection.
276 * sSR -> sSR Might answer late resent SYN.
277 * sES -> sES :-)
278 * sFW -> sCW Normal close request answered by ACK.
279 * sCW -> sCW
280 * sLA -> sTW Last ACK detected.
281 * sTW -> sTW Retransmitted last ACK.
282 * sCL -> sCL
283 */
284 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
285 /*rst*/ { sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sIV },
286 /*none*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV }
287 }
288 };
289
290 static int tcp_pkt_to_tuple(const struct sk_buff *skb,
291 unsigned int dataoff,
292 struct ip_conntrack_tuple *tuple)
293 {
294 struct tcphdr _hdr, *hp;
295
296 /* Actually only need first 8 bytes. */
297 hp = skb_header_pointer(skb, dataoff, 8, &_hdr);
298 if (hp == NULL)
299 return 0;
300
301 tuple->src.u.tcp.port = hp->source;
302 tuple->dst.u.tcp.port = hp->dest;
303
304 return 1;
305 }
306
307 static int tcp_invert_tuple(struct ip_conntrack_tuple *tuple,
308 const struct ip_conntrack_tuple *orig)
309 {
310 tuple->src.u.tcp.port = orig->dst.u.tcp.port;
311 tuple->dst.u.tcp.port = orig->src.u.tcp.port;
312 return 1;
313 }
314
315 /* Print out the per-protocol part of the tuple. */
316 static int tcp_print_tuple(struct seq_file *s,
317 const struct ip_conntrack_tuple *tuple)
318 {
319 return seq_printf(s, "sport=%hu dport=%hu ",
320 ntohs(tuple->src.u.tcp.port),
321 ntohs(tuple->dst.u.tcp.port));
322 }
323
324 /* Print out the private part of the conntrack. */
325 static int tcp_print_conntrack(struct seq_file *s,
326 const struct ip_conntrack *conntrack)
327 {
328 enum tcp_conntrack state;
329
330 read_lock_bh(&tcp_lock);
331 state = conntrack->proto.tcp.state;
332 read_unlock_bh(&tcp_lock);
333
334 return seq_printf(s, "%s ", tcp_conntrack_names[state]);
335 }
336
337 #if defined(CONFIG_IP_NF_CONNTRACK_NETLINK) || \
338 defined(CONFIG_IP_NF_CONNTRACK_NETLINK_MODULE)
339 static int tcp_to_nfattr(struct sk_buff *skb, struct nfattr *nfa,
340 const struct ip_conntrack *ct)
341 {
342 struct nfattr *nest_parms;
343
344 read_lock_bh(&tcp_lock);
345 nest_parms = NFA_NEST(skb, CTA_PROTOINFO_TCP);
346 NFA_PUT(skb, CTA_PROTOINFO_TCP_STATE, sizeof(u_int8_t),
347 &ct->proto.tcp.state);
348 read_unlock_bh(&tcp_lock);
349
350 NFA_NEST_END(skb, nest_parms);
351
352 return 0;
353
354 nfattr_failure:
355 read_unlock_bh(&tcp_lock);
356 return -1;
357 }
358
359 static const size_t cta_min_tcp[CTA_PROTOINFO_TCP_MAX] = {
360 [CTA_PROTOINFO_TCP_STATE-1] = sizeof(u_int8_t),
361 };
362
363 static int nfattr_to_tcp(struct nfattr *cda[], struct ip_conntrack *ct)
364 {
365 struct nfattr *attr = cda[CTA_PROTOINFO_TCP-1];
366 struct nfattr *tb[CTA_PROTOINFO_TCP_MAX];
367
368 /* updates could not contain anything about the private
369 * protocol info, in that case skip the parsing */
370 if (!attr)
371 return 0;
372
373 nfattr_parse_nested(tb, CTA_PROTOINFO_TCP_MAX, attr);
374
375 if (nfattr_bad_size(tb, CTA_PROTOINFO_TCP_MAX, cta_min_tcp))
376 return -EINVAL;
377
378 if (!tb[CTA_PROTOINFO_TCP_STATE-1])
379 return -EINVAL;
380
381 write_lock_bh(&tcp_lock);
382 ct->proto.tcp.state =
383 *(u_int8_t *)NFA_DATA(tb[CTA_PROTOINFO_TCP_STATE-1]);
384 write_unlock_bh(&tcp_lock);
385
386 return 0;
387 }
388 #endif
389
390 static unsigned int get_conntrack_index(const struct tcphdr *tcph)
391 {
392 if (tcph->rst) return TCP_RST_SET;
393 else if (tcph->syn) return (tcph->ack ? TCP_SYNACK_SET : TCP_SYN_SET);
394 else if (tcph->fin) return TCP_FIN_SET;
395 else if (tcph->ack) return TCP_ACK_SET;
396 else return TCP_NONE_SET;
397 }
398
399 /* TCP connection tracking based on 'Real Stateful TCP Packet Filtering
400 in IP Filter' by Guido van Rooij.
401
402 http://www.nluug.nl/events/sane2000/papers.html
403 http://www.iae.nl/users/guido/papers/tcp_filtering.ps.gz
404
405 The boundaries and the conditions are changed according to RFC793:
406 the packet must intersect the window (i.e. segments may be
407 after the right or before the left edge) and thus receivers may ACK
408 segments after the right edge of the window.
409
410 td_maxend = max(sack + max(win,1)) seen in reply packets
411 td_maxwin = max(max(win, 1)) + (sack - ack) seen in sent packets
412 td_maxwin += seq + len - sender.td_maxend
413 if seq + len > sender.td_maxend
414 td_end = max(seq + len) seen in sent packets
415
416 I. Upper bound for valid data: seq <= sender.td_maxend
417 II. Lower bound for valid data: seq + len >= sender.td_end - receiver.td_maxwin
418 III. Upper bound for valid ack: sack <= receiver.td_end
419 IV. Lower bound for valid ack: ack >= receiver.td_end - MAXACKWINDOW
420
421 where sack is the highest right edge of sack block found in the packet.
422
423 The upper bound limit for a valid ack is not ignored -
424 we doesn't have to deal with fragments.
425 */
426
427 static inline __u32 segment_seq_plus_len(__u32 seq,
428 size_t len,
429 struct iphdr *iph,
430 struct tcphdr *tcph)
431 {
432 return (seq + len - (iph->ihl + tcph->doff)*4
433 + (tcph->syn ? 1 : 0) + (tcph->fin ? 1 : 0));
434 }
435
436 /* Fixme: what about big packets? */
437 #define MAXACKWINCONST 66000
438 #define MAXACKWINDOW(sender) \
439 ((sender)->td_maxwin > MAXACKWINCONST ? (sender)->td_maxwin \
440 : MAXACKWINCONST)
441
442 /*
443 * Simplified tcp_parse_options routine from tcp_input.c
444 */
445 static void tcp_options(const struct sk_buff *skb,
446 struct iphdr *iph,
447 struct tcphdr *tcph,
448 struct ip_ct_tcp_state *state)
449 {
450 unsigned char buff[(15 * 4) - sizeof(struct tcphdr)];
451 unsigned char *ptr;
452 int length = (tcph->doff*4) - sizeof(struct tcphdr);
453
454 if (!length)
455 return;
456
457 ptr = skb_header_pointer(skb,
458 (iph->ihl * 4) + sizeof(struct tcphdr),
459 length, buff);
460 BUG_ON(ptr == NULL);
461
462 state->td_scale =
463 state->flags = 0;
464
465 while (length > 0) {
466 int opcode=*ptr++;
467 int opsize;
468
469 switch (opcode) {
470 case TCPOPT_EOL:
471 return;
472 case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */
473 length--;
474 continue;
475 default:
476 opsize=*ptr++;
477 if (opsize < 2) /* "silly options" */
478 return;
479 if (opsize > length)
480 break; /* don't parse partial options */
481
482 if (opcode == TCPOPT_SACK_PERM
483 && opsize == TCPOLEN_SACK_PERM)
484 state->flags |= IP_CT_TCP_FLAG_SACK_PERM;
485 else if (opcode == TCPOPT_WINDOW
486 && opsize == TCPOLEN_WINDOW) {
487 state->td_scale = *(u_int8_t *)ptr;
488
489 if (state->td_scale > 14) {
490 /* See RFC1323 */
491 state->td_scale = 14;
492 }
493 state->flags |=
494 IP_CT_TCP_FLAG_WINDOW_SCALE;
495 }
496 ptr += opsize - 2;
497 length -= opsize;
498 }
499 }
500 }
501
502 static void tcp_sack(const struct sk_buff *skb,
503 struct iphdr *iph,
504 struct tcphdr *tcph,
505 __u32 *sack)
506 {
507 unsigned char buff[(15 * 4) - sizeof(struct tcphdr)];
508 unsigned char *ptr;
509 int length = (tcph->doff*4) - sizeof(struct tcphdr);
510 __u32 tmp;
511
512 if (!length)
513 return;
514
515 ptr = skb_header_pointer(skb,
516 (iph->ihl * 4) + sizeof(struct tcphdr),
517 length, buff);
518 BUG_ON(ptr == NULL);
519
520 /* Fast path for timestamp-only option */
521 if (length == TCPOLEN_TSTAMP_ALIGNED*4
522 && *(__u32 *)ptr ==
523 __constant_ntohl((TCPOPT_NOP << 24)
524 | (TCPOPT_NOP << 16)
525 | (TCPOPT_TIMESTAMP << 8)
526 | TCPOLEN_TIMESTAMP))
527 return;
528
529 while (length > 0) {
530 int opcode=*ptr++;
531 int opsize, i;
532
533 switch (opcode) {
534 case TCPOPT_EOL:
535 return;
536 case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */
537 length--;
538 continue;
539 default:
540 opsize=*ptr++;
541 if (opsize < 2) /* "silly options" */
542 return;
543 if (opsize > length)
544 break; /* don't parse partial options */
545
546 if (opcode == TCPOPT_SACK
547 && opsize >= (TCPOLEN_SACK_BASE
548 + TCPOLEN_SACK_PERBLOCK)
549 && !((opsize - TCPOLEN_SACK_BASE)
550 % TCPOLEN_SACK_PERBLOCK)) {
551 for (i = 0;
552 i < (opsize - TCPOLEN_SACK_BASE);
553 i += TCPOLEN_SACK_PERBLOCK) {
554 tmp = ntohl(*((u_int32_t *)(ptr+i)+1));
555
556 if (after(tmp, *sack))
557 *sack = tmp;
558 }
559 return;
560 }
561 ptr += opsize - 2;
562 length -= opsize;
563 }
564 }
565 }
566
567 static int tcp_in_window(struct ip_ct_tcp *state,
568 enum ip_conntrack_dir dir,
569 unsigned int index,
570 const struct sk_buff *skb,
571 struct iphdr *iph,
572 struct tcphdr *tcph)
573 {
574 struct ip_ct_tcp_state *sender = &state->seen[dir];
575 struct ip_ct_tcp_state *receiver = &state->seen[!dir];
576 __u32 seq, ack, sack, end, win, swin;
577 int res;
578
579 /*
580 * Get the required data from the packet.
581 */
582 seq = ntohl(tcph->seq);
583 ack = sack = ntohl(tcph->ack_seq);
584 win = ntohs(tcph->window);
585 end = segment_seq_plus_len(seq, skb->len, iph, tcph);
586
587 if (receiver->flags & IP_CT_TCP_FLAG_SACK_PERM)
588 tcp_sack(skb, iph, tcph, &sack);
589
590 DEBUGP("tcp_in_window: START\n");
591 DEBUGP("tcp_in_window: src=%u.%u.%u.%u:%hu dst=%u.%u.%u.%u:%hu "
592 "seq=%u ack=%u sack=%u win=%u end=%u\n",
593 NIPQUAD(iph->saddr), ntohs(tcph->source),
594 NIPQUAD(iph->daddr), ntohs(tcph->dest),
595 seq, ack, sack, win, end);
596 DEBUGP("tcp_in_window: sender end=%u maxend=%u maxwin=%u scale=%i "
597 "receiver end=%u maxend=%u maxwin=%u scale=%i\n",
598 sender->td_end, sender->td_maxend, sender->td_maxwin,
599 sender->td_scale,
600 receiver->td_end, receiver->td_maxend, receiver->td_maxwin,
601 receiver->td_scale);
602
603 if (sender->td_end == 0) {
604 /*
605 * Initialize sender data.
606 */
607 if (tcph->syn && tcph->ack) {
608 /*
609 * Outgoing SYN-ACK in reply to a SYN.
610 */
611 sender->td_end =
612 sender->td_maxend = end;
613 sender->td_maxwin = (win == 0 ? 1 : win);
614
615 tcp_options(skb, iph, tcph, sender);
616 /*
617 * RFC 1323:
618 * Both sides must send the Window Scale option
619 * to enable window scaling in either direction.
620 */
621 if (!(sender->flags & IP_CT_TCP_FLAG_WINDOW_SCALE
622 && receiver->flags & IP_CT_TCP_FLAG_WINDOW_SCALE))
623 sender->td_scale =
624 receiver->td_scale = 0;
625 } else {
626 /*
627 * We are in the middle of a connection,
628 * its history is lost for us.
629 * Let's try to use the data from the packet.
630 */
631 sender->td_end = end;
632 sender->td_maxwin = (win == 0 ? 1 : win);
633 sender->td_maxend = end + sender->td_maxwin;
634 }
635 } else if (((state->state == TCP_CONNTRACK_SYN_SENT
636 && dir == IP_CT_DIR_ORIGINAL)
637 || (state->state == TCP_CONNTRACK_SYN_RECV
638 && dir == IP_CT_DIR_REPLY))
639 && after(end, sender->td_end)) {
640 /*
641 * RFC 793: "if a TCP is reinitialized ... then it need
642 * not wait at all; it must only be sure to use sequence
643 * numbers larger than those recently used."
644 */
645 sender->td_end =
646 sender->td_maxend = end;
647 sender->td_maxwin = (win == 0 ? 1 : win);
648
649 tcp_options(skb, iph, tcph, sender);
650 }
651
652 if (!(tcph->ack)) {
653 /*
654 * If there is no ACK, just pretend it was set and OK.
655 */
656 ack = sack = receiver->td_end;
657 } else if (((tcp_flag_word(tcph) & (TCP_FLAG_ACK|TCP_FLAG_RST)) ==
658 (TCP_FLAG_ACK|TCP_FLAG_RST))
659 && (ack == 0)) {
660 /*
661 * Broken TCP stacks, that set ACK in RST packets as well
662 * with zero ack value.
663 */
664 ack = sack = receiver->td_end;
665 }
666
667 if (seq == end
668 && (!tcph->rst
669 || (seq == 0 && state->state == TCP_CONNTRACK_SYN_SENT)))
670 /*
671 * Packets contains no data: we assume it is valid
672 * and check the ack value only.
673 * However RST segments are always validated by their
674 * SEQ number, except when seq == 0 (reset sent answering
675 * SYN.
676 */
677 seq = end = sender->td_end;
678
679 DEBUGP("tcp_in_window: src=%u.%u.%u.%u:%hu dst=%u.%u.%u.%u:%hu "
680 "seq=%u ack=%u sack =%u win=%u end=%u\n",
681 NIPQUAD(iph->saddr), ntohs(tcph->source),
682 NIPQUAD(iph->daddr), ntohs(tcph->dest),
683 seq, ack, sack, win, end);
684 DEBUGP("tcp_in_window: sender end=%u maxend=%u maxwin=%u scale=%i "
685 "receiver end=%u maxend=%u maxwin=%u scale=%i\n",
686 sender->td_end, sender->td_maxend, sender->td_maxwin,
687 sender->td_scale,
688 receiver->td_end, receiver->td_maxend, receiver->td_maxwin,
689 receiver->td_scale);
690
691 DEBUGP("tcp_in_window: I=%i II=%i III=%i IV=%i\n",
692 before(seq, sender->td_maxend + 1),
693 after(end, sender->td_end - receiver->td_maxwin - 1),
694 before(sack, receiver->td_end + 1),
695 after(ack, receiver->td_end - MAXACKWINDOW(sender)));
696
697 if (sender->loose || receiver->loose ||
698 (before(seq, sender->td_maxend + 1) &&
699 after(end, sender->td_end - receiver->td_maxwin - 1) &&
700 before(sack, receiver->td_end + 1) &&
701 after(ack, receiver->td_end - MAXACKWINDOW(sender)))) {
702 /*
703 * Take into account window scaling (RFC 1323).
704 */
705 if (!tcph->syn)
706 win <<= sender->td_scale;
707
708 /*
709 * Update sender data.
710 */
711 swin = win + (sack - ack);
712 if (sender->td_maxwin < swin)
713 sender->td_maxwin = swin;
714 if (after(end, sender->td_end))
715 sender->td_end = end;
716 /*
717 * Update receiver data.
718 */
719 if (after(end, sender->td_maxend))
720 receiver->td_maxwin += end - sender->td_maxend;
721 if (after(sack + win, receiver->td_maxend - 1)) {
722 receiver->td_maxend = sack + win;
723 if (win == 0)
724 receiver->td_maxend++;
725 }
726
727 /*
728 * Check retransmissions.
729 */
730 if (index == TCP_ACK_SET) {
731 if (state->last_dir == dir
732 && state->last_seq == seq
733 && state->last_ack == ack
734 && state->last_end == end)
735 state->retrans++;
736 else {
737 state->last_dir = dir;
738 state->last_seq = seq;
739 state->last_ack = ack;
740 state->last_end = end;
741 state->retrans = 0;
742 }
743 }
744 /*
745 * Close the window of disabled window tracking :-)
746 */
747 if (sender->loose)
748 sender->loose--;
749
750 res = 1;
751 } else {
752 if (LOG_INVALID(IPPROTO_TCP))
753 nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
754 "ip_ct_tcp: %s ",
755 before(seq, sender->td_maxend + 1) ?
756 after(end, sender->td_end - receiver->td_maxwin - 1) ?
757 before(sack, receiver->td_end + 1) ?
758 after(ack, receiver->td_end - MAXACKWINDOW(sender)) ? "BUG"
759 : "ACK is under the lower bound (possible overly delayed ACK)"
760 : "ACK is over the upper bound (ACKed data not seen yet)"
761 : "SEQ is under the lower bound (already ACKed data retransmitted)"
762 : "SEQ is over the upper bound (over the window of the receiver)");
763
764 res = ip_ct_tcp_be_liberal;
765 }
766
767 DEBUGP("tcp_in_window: res=%i sender end=%u maxend=%u maxwin=%u "
768 "receiver end=%u maxend=%u maxwin=%u\n",
769 res, sender->td_end, sender->td_maxend, sender->td_maxwin,
770 receiver->td_end, receiver->td_maxend, receiver->td_maxwin);
771
772 return res;
773 }
774
775 #ifdef CONFIG_IP_NF_NAT_NEEDED
776 /* Update sender->td_end after NAT successfully mangled the packet */
777 void ip_conntrack_tcp_update(struct sk_buff *skb,
778 struct ip_conntrack *conntrack,
779 enum ip_conntrack_dir dir)
780 {
781 struct iphdr *iph = skb->nh.iph;
782 struct tcphdr *tcph = (void *)skb->nh.iph + skb->nh.iph->ihl*4;
783 __u32 end;
784 #ifdef DEBUGP_VARS
785 struct ip_ct_tcp_state *sender = &conntrack->proto.tcp.seen[dir];
786 struct ip_ct_tcp_state *receiver = &conntrack->proto.tcp.seen[!dir];
787 #endif
788
789 end = segment_seq_plus_len(ntohl(tcph->seq), skb->len, iph, tcph);
790
791 write_lock_bh(&tcp_lock);
792 /*
793 * We have to worry for the ack in the reply packet only...
794 */
795 if (after(end, conntrack->proto.tcp.seen[dir].td_end))
796 conntrack->proto.tcp.seen[dir].td_end = end;
797 conntrack->proto.tcp.last_end = end;
798 write_unlock_bh(&tcp_lock);
799 DEBUGP("tcp_update: sender end=%u maxend=%u maxwin=%u scale=%i "
800 "receiver end=%u maxend=%u maxwin=%u scale=%i\n",
801 sender->td_end, sender->td_maxend, sender->td_maxwin,
802 sender->td_scale,
803 receiver->td_end, receiver->td_maxend, receiver->td_maxwin,
804 receiver->td_scale);
805 }
806
807 #endif
808
809 #define TH_FIN 0x01
810 #define TH_SYN 0x02
811 #define TH_RST 0x04
812 #define TH_PUSH 0x08
813 #define TH_ACK 0x10
814 #define TH_URG 0x20
815 #define TH_ECE 0x40
816 #define TH_CWR 0x80
817
818 /* table of valid flag combinations - ECE and CWR are always valid */
819 static const u8 tcp_valid_flags[(TH_FIN|TH_SYN|TH_RST|TH_PUSH|TH_ACK|TH_URG) + 1] =
820 {
821 [TH_SYN] = 1,
822 [TH_SYN|TH_ACK] = 1,
823 [TH_SYN|TH_PUSH] = 1,
824 [TH_SYN|TH_ACK|TH_PUSH] = 1,
825 [TH_RST] = 1,
826 [TH_RST|TH_ACK] = 1,
827 [TH_RST|TH_ACK|TH_PUSH] = 1,
828 [TH_FIN|TH_ACK] = 1,
829 [TH_ACK] = 1,
830 [TH_ACK|TH_PUSH] = 1,
831 [TH_ACK|TH_URG] = 1,
832 [TH_ACK|TH_URG|TH_PUSH] = 1,
833 [TH_FIN|TH_ACK|TH_PUSH] = 1,
834 [TH_FIN|TH_ACK|TH_URG] = 1,
835 [TH_FIN|TH_ACK|TH_URG|TH_PUSH] = 1,
836 };
837
838 /* Protect conntrack agaist broken packets. Code taken from ipt_unclean.c. */
839 static int tcp_error(struct sk_buff *skb,
840 enum ip_conntrack_info *ctinfo,
841 unsigned int hooknum)
842 {
843 struct iphdr *iph = skb->nh.iph;
844 struct tcphdr _tcph, *th;
845 unsigned int tcplen = skb->len - iph->ihl * 4;
846 u_int8_t tcpflags;
847
848 /* Smaller that minimal TCP header? */
849 th = skb_header_pointer(skb, iph->ihl * 4,
850 sizeof(_tcph), &_tcph);
851 if (th == NULL) {
852 if (LOG_INVALID(IPPROTO_TCP))
853 nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
854 "ip_ct_tcp: short packet ");
855 return -NF_ACCEPT;
856 }
857
858 /* Not whole TCP header or malformed packet */
859 if (th->doff*4 < sizeof(struct tcphdr) || tcplen < th->doff*4) {
860 if (LOG_INVALID(IPPROTO_TCP))
861 nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
862 "ip_ct_tcp: truncated/malformed packet ");
863 return -NF_ACCEPT;
864 }
865
866 /* Checksum invalid? Ignore.
867 * We skip checking packets on the outgoing path
868 * because it is assumed to be correct.
869 */
870 /* FIXME: Source route IP option packets --RR */
871 if (ip_conntrack_checksum && hooknum == NF_IP_PRE_ROUTING &&
872 nf_ip_checksum(skb, hooknum, iph->ihl * 4, IPPROTO_TCP)) {
873 if (LOG_INVALID(IPPROTO_TCP))
874 nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
875 "ip_ct_tcp: bad TCP checksum ");
876 return -NF_ACCEPT;
877 }
878
879 /* Check TCP flags. */
880 tcpflags = (((u_int8_t *)th)[13] & ~(TH_ECE|TH_CWR));
881 if (!tcp_valid_flags[tcpflags]) {
882 if (LOG_INVALID(IPPROTO_TCP))
883 nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
884 "ip_ct_tcp: invalid TCP flag combination ");
885 return -NF_ACCEPT;
886 }
887
888 return NF_ACCEPT;
889 }
890
891 /* Returns verdict for packet, or -1 for invalid. */
892 static int tcp_packet(struct ip_conntrack *conntrack,
893 const struct sk_buff *skb,
894 enum ip_conntrack_info ctinfo)
895 {
896 enum tcp_conntrack new_state, old_state;
897 enum ip_conntrack_dir dir;
898 struct iphdr *iph = skb->nh.iph;
899 struct tcphdr *th, _tcph;
900 unsigned long timeout;
901 unsigned int index;
902
903 th = skb_header_pointer(skb, iph->ihl * 4,
904 sizeof(_tcph), &_tcph);
905 BUG_ON(th == NULL);
906
907 write_lock_bh(&tcp_lock);
908 old_state = conntrack->proto.tcp.state;
909 dir = CTINFO2DIR(ctinfo);
910 index = get_conntrack_index(th);
911 new_state = tcp_conntracks[dir][index][old_state];
912
913 switch (new_state) {
914 case TCP_CONNTRACK_IGNORE:
915 /* Ignored packets:
916 *
917 * a) SYN in ORIGINAL
918 * b) SYN/ACK in REPLY
919 * c) ACK in reply direction after initial SYN in original.
920 */
921 if (index == TCP_SYNACK_SET
922 && conntrack->proto.tcp.last_index == TCP_SYN_SET
923 && conntrack->proto.tcp.last_dir != dir
924 && ntohl(th->ack_seq) ==
925 conntrack->proto.tcp.last_end) {
926 /* This SYN/ACK acknowledges a SYN that we earlier
927 * ignored as invalid. This means that the client and
928 * the server are both in sync, while the firewall is
929 * not. We kill this session and block the SYN/ACK so
930 * that the client cannot but retransmit its SYN and
931 * thus initiate a clean new session.
932 */
933 write_unlock_bh(&tcp_lock);
934 if (LOG_INVALID(IPPROTO_TCP))
935 nf_log_packet(PF_INET, 0, skb, NULL, NULL,
936 NULL, "ip_ct_tcp: "
937 "killing out of sync session ");
938 if (del_timer(&conntrack->timeout))
939 conntrack->timeout.function((unsigned long)
940 conntrack);
941 return -NF_DROP;
942 }
943 conntrack->proto.tcp.last_index = index;
944 conntrack->proto.tcp.last_dir = dir;
945 conntrack->proto.tcp.last_seq = ntohl(th->seq);
946 conntrack->proto.tcp.last_end =
947 segment_seq_plus_len(ntohl(th->seq), skb->len, iph, th);
948
949 write_unlock_bh(&tcp_lock);
950 if (LOG_INVALID(IPPROTO_TCP))
951 nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
952 "ip_ct_tcp: invalid packet ignored ");
953 return NF_ACCEPT;
954 case TCP_CONNTRACK_MAX:
955 /* Invalid packet */
956 DEBUGP("ip_ct_tcp: Invalid dir=%i index=%u ostate=%u\n",
957 dir, get_conntrack_index(th),
958 old_state);
959 write_unlock_bh(&tcp_lock);
960 if (LOG_INVALID(IPPROTO_TCP))
961 nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
962 "ip_ct_tcp: invalid state ");
963 return -NF_ACCEPT;
964 case TCP_CONNTRACK_SYN_SENT:
965 if (old_state < TCP_CONNTRACK_TIME_WAIT)
966 break;
967 if ((conntrack->proto.tcp.seen[dir].flags &
968 IP_CT_TCP_FLAG_CLOSE_INIT)
969 || after(ntohl(th->seq),
970 conntrack->proto.tcp.seen[dir].td_end)) {
971 /* Attempt to reopen a closed connection.
972 * Delete this connection and look up again. */
973 write_unlock_bh(&tcp_lock);
974 if (del_timer(&conntrack->timeout))
975 conntrack->timeout.function((unsigned long)
976 conntrack);
977 return -NF_REPEAT;
978 } else {
979 write_unlock_bh(&tcp_lock);
980 if (LOG_INVALID(IPPROTO_TCP))
981 nf_log_packet(PF_INET, 0, skb, NULL, NULL,
982 NULL, "ip_ct_tcp: invalid SYN");
983 return -NF_ACCEPT;
984 }
985 case TCP_CONNTRACK_CLOSE:
986 if (index == TCP_RST_SET
987 && ((test_bit(IPS_SEEN_REPLY_BIT, &conntrack->status)
988 && conntrack->proto.tcp.last_index == TCP_SYN_SET)
989 || (!test_bit(IPS_ASSURED_BIT, &conntrack->status)
990 && conntrack->proto.tcp.last_index == TCP_ACK_SET))
991 && ntohl(th->ack_seq) == conntrack->proto.tcp.last_end) {
992 /* RST sent to invalid SYN or ACK we had let through
993 * at a) and c) above:
994 *
995 * a) SYN was in window then
996 * c) we hold a half-open connection.
997 *
998 * Delete our connection entry.
999 * We skip window checking, because packet might ACK
1000 * segments we ignored. */
1001 goto in_window;
1002 }
1003 /* Just fall through */
1004 default:
1005 /* Keep compilers happy. */
1006 break;
1007 }
1008
1009 if (!tcp_in_window(&conntrack->proto.tcp, dir, index,
1010 skb, iph, th)) {
1011 write_unlock_bh(&tcp_lock);
1012 return -NF_ACCEPT;
1013 }
1014 in_window:
1015 /* From now on we have got in-window packets */
1016 conntrack->proto.tcp.last_index = index;
1017
1018 DEBUGP("tcp_conntracks: src=%u.%u.%u.%u:%hu dst=%u.%u.%u.%u:%hu "
1019 "syn=%i ack=%i fin=%i rst=%i old=%i new=%i\n",
1020 NIPQUAD(iph->saddr), ntohs(th->source),
1021 NIPQUAD(iph->daddr), ntohs(th->dest),
1022 (th->syn ? 1 : 0), (th->ack ? 1 : 0),
1023 (th->fin ? 1 : 0), (th->rst ? 1 : 0),
1024 old_state, new_state);
1025
1026 conntrack->proto.tcp.state = new_state;
1027 if (old_state != new_state
1028 && (new_state == TCP_CONNTRACK_FIN_WAIT
1029 || new_state == TCP_CONNTRACK_CLOSE))
1030 conntrack->proto.tcp.seen[dir].flags |= IP_CT_TCP_FLAG_CLOSE_INIT;
1031 timeout = conntrack->proto.tcp.retrans >= ip_ct_tcp_max_retrans
1032 && *tcp_timeouts[new_state] > ip_ct_tcp_timeout_max_retrans
1033 ? ip_ct_tcp_timeout_max_retrans : *tcp_timeouts[new_state];
1034 write_unlock_bh(&tcp_lock);
1035
1036 ip_conntrack_event_cache(IPCT_PROTOINFO_VOLATILE, skb);
1037 if (new_state != old_state)
1038 ip_conntrack_event_cache(IPCT_PROTOINFO, skb);
1039
1040 if (!test_bit(IPS_SEEN_REPLY_BIT, &conntrack->status)) {
1041 /* If only reply is a RST, we can consider ourselves not to
1042 have an established connection: this is a fairly common
1043 problem case, so we can delete the conntrack
1044 immediately. --RR */
1045 if (th->rst) {
1046 if (del_timer(&conntrack->timeout))
1047 conntrack->timeout.function((unsigned long)
1048 conntrack);
1049 return NF_ACCEPT;
1050 }
1051 } else if (!test_bit(IPS_ASSURED_BIT, &conntrack->status)
1052 && (old_state == TCP_CONNTRACK_SYN_RECV
1053 || old_state == TCP_CONNTRACK_ESTABLISHED)
1054 && new_state == TCP_CONNTRACK_ESTABLISHED) {
1055 /* Set ASSURED if we see see valid ack in ESTABLISHED
1056 after SYN_RECV or a valid answer for a picked up
1057 connection. */
1058 set_bit(IPS_ASSURED_BIT, &conntrack->status);
1059 ip_conntrack_event_cache(IPCT_STATUS, skb);
1060 }
1061 ip_ct_refresh_acct(conntrack, ctinfo, skb, timeout);
1062
1063 return NF_ACCEPT;
1064 }
1065
1066 /* Called when a new connection for this protocol found. */
1067 static int tcp_new(struct ip_conntrack *conntrack,
1068 const struct sk_buff *skb)
1069 {
1070 enum tcp_conntrack new_state;
1071 struct iphdr *iph = skb->nh.iph;
1072 struct tcphdr *th, _tcph;
1073 #ifdef DEBUGP_VARS
1074 struct ip_ct_tcp_state *sender = &conntrack->proto.tcp.seen[0];
1075 struct ip_ct_tcp_state *receiver = &conntrack->proto.tcp.seen[1];
1076 #endif
1077
1078 th = skb_header_pointer(skb, iph->ihl * 4,
1079 sizeof(_tcph), &_tcph);
1080 BUG_ON(th == NULL);
1081
1082 /* Don't need lock here: this conntrack not in circulation yet */
1083 new_state
1084 = tcp_conntracks[0][get_conntrack_index(th)]
1085 [TCP_CONNTRACK_NONE];
1086
1087 /* Invalid: delete conntrack */
1088 if (new_state >= TCP_CONNTRACK_MAX) {
1089 DEBUGP("ip_ct_tcp: invalid new deleting.\n");
1090 return 0;
1091 }
1092
1093 if (new_state == TCP_CONNTRACK_SYN_SENT) {
1094 /* SYN packet */
1095 conntrack->proto.tcp.seen[0].td_end =
1096 segment_seq_plus_len(ntohl(th->seq), skb->len,
1097 iph, th);
1098 conntrack->proto.tcp.seen[0].td_maxwin = ntohs(th->window);
1099 if (conntrack->proto.tcp.seen[0].td_maxwin == 0)
1100 conntrack->proto.tcp.seen[0].td_maxwin = 1;
1101 conntrack->proto.tcp.seen[0].td_maxend =
1102 conntrack->proto.tcp.seen[0].td_end;
1103
1104 tcp_options(skb, iph, th, &conntrack->proto.tcp.seen[0]);
1105 conntrack->proto.tcp.seen[1].flags = 0;
1106 conntrack->proto.tcp.seen[0].loose =
1107 conntrack->proto.tcp.seen[1].loose = 0;
1108 } else if (ip_ct_tcp_loose == 0) {
1109 /* Don't try to pick up connections. */
1110 return 0;
1111 } else {
1112 /*
1113 * We are in the middle of a connection,
1114 * its history is lost for us.
1115 * Let's try to use the data from the packet.
1116 */
1117 conntrack->proto.tcp.seen[0].td_end =
1118 segment_seq_plus_len(ntohl(th->seq), skb->len,
1119 iph, th);
1120 conntrack->proto.tcp.seen[0].td_maxwin = ntohs(th->window);
1121 if (conntrack->proto.tcp.seen[0].td_maxwin == 0)
1122 conntrack->proto.tcp.seen[0].td_maxwin = 1;
1123 conntrack->proto.tcp.seen[0].td_maxend =
1124 conntrack->proto.tcp.seen[0].td_end +
1125 conntrack->proto.tcp.seen[0].td_maxwin;
1126 conntrack->proto.tcp.seen[0].td_scale = 0;
1127
1128 /* We assume SACK. Should we assume window scaling too? */
1129 conntrack->proto.tcp.seen[0].flags =
1130 conntrack->proto.tcp.seen[1].flags = IP_CT_TCP_FLAG_SACK_PERM;
1131 conntrack->proto.tcp.seen[0].loose =
1132 conntrack->proto.tcp.seen[1].loose = ip_ct_tcp_loose;
1133 }
1134
1135 conntrack->proto.tcp.seen[1].td_end = 0;
1136 conntrack->proto.tcp.seen[1].td_maxend = 0;
1137 conntrack->proto.tcp.seen[1].td_maxwin = 1;
1138 conntrack->proto.tcp.seen[1].td_scale = 0;
1139
1140 /* tcp_packet will set them */
1141 conntrack->proto.tcp.state = TCP_CONNTRACK_NONE;
1142 conntrack->proto.tcp.last_index = TCP_NONE_SET;
1143
1144 DEBUGP("tcp_new: sender end=%u maxend=%u maxwin=%u scale=%i "
1145 "receiver end=%u maxend=%u maxwin=%u scale=%i\n",
1146 sender->td_end, sender->td_maxend, sender->td_maxwin,
1147 sender->td_scale,
1148 receiver->td_end, receiver->td_maxend, receiver->td_maxwin,
1149 receiver->td_scale);
1150 return 1;
1151 }
1152
1153 struct ip_conntrack_protocol ip_conntrack_protocol_tcp =
1154 {
1155 .proto = IPPROTO_TCP,
1156 .name = "tcp",
1157 .pkt_to_tuple = tcp_pkt_to_tuple,
1158 .invert_tuple = tcp_invert_tuple,
1159 .print_tuple = tcp_print_tuple,
1160 .print_conntrack = tcp_print_conntrack,
1161 .packet = tcp_packet,
1162 .new = tcp_new,
1163 .error = tcp_error,
1164 #if defined(CONFIG_IP_NF_CONNTRACK_NETLINK) || \
1165 defined(CONFIG_IP_NF_CONNTRACK_NETLINK_MODULE)
1166 .to_nfattr = tcp_to_nfattr,
1167 .from_nfattr = nfattr_to_tcp,
1168 .tuple_to_nfattr = ip_ct_port_tuple_to_nfattr,
1169 .nfattr_to_tuple = ip_ct_port_nfattr_to_tuple,
1170 #endif
1171 };
Linux kernel - Deliverables
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