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Merge branch 'master'
[deliverable/linux.git] / net / netfilter / nf_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 * 27 Oct 2004: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
20 * - genelized Layer 3 protocol part.
21 *
22 * Derived from net/ipv4/netfilter/ip_conntrack_proto_tcp.c
23 *
24 * version 2.2
25 */
26
27 #include <linux/config.h>
28 #include <linux/types.h>
29 #include <linux/sched.h>
30 #include <linux/timer.h>
31 #include <linux/netfilter.h>
32 #include <linux/module.h>
33 #include <linux/in.h>
34 #include <linux/tcp.h>
35 #include <linux/spinlock.h>
36 #include <linux/skbuff.h>
37 #include <linux/ipv6.h>
38 #include <net/ip6_checksum.h>
39
40 #include <net/tcp.h>
41
42 #include <linux/netfilter.h>
43 #include <linux/netfilter_ipv4.h>
44 #include <linux/netfilter_ipv6.h>
45 #include <net/netfilter/nf_conntrack.h>
46 #include <net/netfilter/nf_conntrack_protocol.h>
47
48 #if 0
49 #define DEBUGP printk
50 #define DEBUGP_VARS
51 #else
52 #define DEBUGP(format, args...)
53 #endif
54
55 /* Protects conntrack->proto.tcp */
56 static DEFINE_RWLOCK(tcp_lock);
57
58 /* "Be conservative in what you do,
59 be liberal in what you accept from others."
60 If it's non-zero, we mark only out of window RST segments as INVALID. */
61 int nf_ct_tcp_be_liberal = 0;
62
63 /* When connection is picked up from the middle, how many packets are required
64 to pass in each direction when we assume we are in sync - if any side uses
65 window scaling, we lost the game.
66 If it is set to zero, we disable picking up already established
67 connections. */
68 int nf_ct_tcp_loose = 3;
69
70 /* Max number of the retransmitted packets without receiving an (acceptable)
71 ACK from the destination. If this number is reached, a shorter timer
72 will be started. */
73 int nf_ct_tcp_max_retrans = 3;
74
75 /* FIXME: Examine ipfilter's timeouts and conntrack transitions more
76 closely. They're more complex. --RR */
77
78 static const char *tcp_conntrack_names[] = {
79 "NONE",
80 "SYN_SENT",
81 "SYN_RECV",
82 "ESTABLISHED",
83 "FIN_WAIT",
84 "CLOSE_WAIT",
85 "LAST_ACK",
86 "TIME_WAIT",
87 "CLOSE",
88 "LISTEN"
89 };
90
91 #define SECS * HZ
92 #define MINS * 60 SECS
93 #define HOURS * 60 MINS
94 #define DAYS * 24 HOURS
95
96 unsigned int nf_ct_tcp_timeout_syn_sent = 2 MINS;
97 unsigned int nf_ct_tcp_timeout_syn_recv = 60 SECS;
98 unsigned int nf_ct_tcp_timeout_established = 5 DAYS;
99 unsigned int nf_ct_tcp_timeout_fin_wait = 2 MINS;
100 unsigned int nf_ct_tcp_timeout_close_wait = 60 SECS;
101 unsigned int nf_ct_tcp_timeout_last_ack = 30 SECS;
102 unsigned int nf_ct_tcp_timeout_time_wait = 2 MINS;
103 unsigned int nf_ct_tcp_timeout_close = 10 SECS;
104
105 /* RFC1122 says the R2 limit should be at least 100 seconds.
106 Linux uses 15 packets as limit, which corresponds
107 to ~13-30min depending on RTO. */
108 unsigned int nf_ct_tcp_timeout_max_retrans = 5 MINS;
109
110 static unsigned int * tcp_timeouts[]
111 = { NULL, /* TCP_CONNTRACK_NONE */
112 &nf_ct_tcp_timeout_syn_sent, /* TCP_CONNTRACK_SYN_SENT, */
113 &nf_ct_tcp_timeout_syn_recv, /* TCP_CONNTRACK_SYN_RECV, */
114 &nf_ct_tcp_timeout_established, /* TCP_CONNTRACK_ESTABLISHED, */
115 &nf_ct_tcp_timeout_fin_wait, /* TCP_CONNTRACK_FIN_WAIT, */
116 &nf_ct_tcp_timeout_close_wait, /* TCP_CONNTRACK_CLOSE_WAIT, */
117 &nf_ct_tcp_timeout_last_ack, /* TCP_CONNTRACK_LAST_ACK, */
118 &nf_ct_tcp_timeout_time_wait, /* TCP_CONNTRACK_TIME_WAIT, */
119 &nf_ct_tcp_timeout_close, /* TCP_CONNTRACK_CLOSE, */
120 NULL, /* TCP_CONNTRACK_LISTEN */
121 };
122
123 #define sNO TCP_CONNTRACK_NONE
124 #define sSS TCP_CONNTRACK_SYN_SENT
125 #define sSR TCP_CONNTRACK_SYN_RECV
126 #define sES TCP_CONNTRACK_ESTABLISHED
127 #define sFW TCP_CONNTRACK_FIN_WAIT
128 #define sCW TCP_CONNTRACK_CLOSE_WAIT
129 #define sLA TCP_CONNTRACK_LAST_ACK
130 #define sTW TCP_CONNTRACK_TIME_WAIT
131 #define sCL TCP_CONNTRACK_CLOSE
132 #define sLI TCP_CONNTRACK_LISTEN
133 #define sIV TCP_CONNTRACK_MAX
134 #define sIG TCP_CONNTRACK_IGNORE
135
136 /* What TCP flags are set from RST/SYN/FIN/ACK. */
137 enum tcp_bit_set {
138 TCP_SYN_SET,
139 TCP_SYNACK_SET,
140 TCP_FIN_SET,
141 TCP_ACK_SET,
142 TCP_RST_SET,
143 TCP_NONE_SET,
144 };
145
146 /*
147 * The TCP state transition table needs a few words...
148 *
149 * We are the man in the middle. All the packets go through us
150 * but might get lost in transit to the destination.
151 * It is assumed that the destinations can't receive segments
152 * we haven't seen.
153 *
154 * The checked segment is in window, but our windows are *not*
155 * equivalent with the ones of the sender/receiver. We always
156 * try to guess the state of the current sender.
157 *
158 * The meaning of the states are:
159 *
160 * NONE: initial state
161 * SYN_SENT: SYN-only packet seen
162 * SYN_RECV: SYN-ACK packet seen
163 * ESTABLISHED: ACK packet seen
164 * FIN_WAIT: FIN packet seen
165 * CLOSE_WAIT: ACK seen (after FIN)
166 * LAST_ACK: FIN seen (after FIN)
167 * TIME_WAIT: last ACK seen
168 * CLOSE: closed connection
169 *
170 * LISTEN state is not used.
171 *
172 * Packets marked as IGNORED (sIG):
173 * if they may be either invalid or valid
174 * and the receiver may send back a connection
175 * closing RST or a SYN/ACK.
176 *
177 * Packets marked as INVALID (sIV):
178 * if they are invalid
179 * or we do not support the request (simultaneous open)
180 */
181 static enum tcp_conntrack tcp_conntracks[2][6][TCP_CONNTRACK_MAX] = {
182 {
183 /* ORIGINAL */
184 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
185 /*syn*/ { sSS, sSS, sIG, sIG, sIG, sIG, sIG, sSS, sSS, sIV },
186 /*
187 * sNO -> sSS Initialize a new connection
188 * sSS -> sSS Retransmitted SYN
189 * sSR -> sIG Late retransmitted SYN?
190 * sES -> sIG Error: SYNs in window outside the SYN_SENT state
191 * are errors. Receiver will reply with RST
192 * and close the connection.
193 * Or we are not in sync and hold a dead connection.
194 * sFW -> sIG
195 * sCW -> sIG
196 * sLA -> sIG
197 * sTW -> sSS Reopened connection (RFC 1122).
198 * sCL -> sSS
199 */
200 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
201 /*synack*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV },
202 /*
203 * A SYN/ACK from the client is always invalid:
204 * - either it tries to set up a simultaneous open, which is
205 * not supported;
206 * - or the firewall has just been inserted between the two hosts
207 * during the session set-up. The SYN will be retransmitted
208 * by the true client (or it'll time out).
209 */
210 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
211 /*fin*/ { sIV, sIV, sFW, sFW, sLA, sLA, sLA, sTW, sCL, sIV },
212 /*
213 * sNO -> sIV Too late and no reason to do anything...
214 * sSS -> sIV Client migth not send FIN in this state:
215 * we enforce waiting for a SYN/ACK reply first.
216 * sSR -> sFW Close started.
217 * sES -> sFW
218 * sFW -> sLA FIN seen in both directions, waiting for
219 * the last ACK.
220 * Migth be a retransmitted FIN as well...
221 * sCW -> sLA
222 * sLA -> sLA Retransmitted FIN. Remain in the same state.
223 * sTW -> sTW
224 * sCL -> sCL
225 */
226 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
227 /*ack*/ { sES, sIV, sES, sES, sCW, sCW, sTW, sTW, sCL, sIV },
228 /*
229 * sNO -> sES Assumed.
230 * sSS -> sIV ACK is invalid: we haven't seen a SYN/ACK yet.
231 * sSR -> sES Established state is reached.
232 * sES -> sES :-)
233 * sFW -> sCW Normal close request answered by ACK.
234 * sCW -> sCW
235 * sLA -> sTW Last ACK detected.
236 * sTW -> sTW Retransmitted last ACK. Remain in the same state.
237 * sCL -> sCL
238 */
239 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
240 /*rst*/ { sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sIV },
241 /*none*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV }
242 },
243 {
244 /* REPLY */
245 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
246 /*syn*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV },
247 /*
248 * sNO -> sIV Never reached.
249 * sSS -> sIV Simultaneous open, not supported
250 * sSR -> sIV Simultaneous open, not supported.
251 * sES -> sIV Server may not initiate a connection.
252 * sFW -> sIV
253 * sCW -> sIV
254 * sLA -> sIV
255 * sTW -> sIV Reopened connection, but server may not do it.
256 * sCL -> sIV
257 */
258 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
259 /*synack*/ { sIV, sSR, sSR, sIG, sIG, sIG, sIG, sIG, sIG, sIV },
260 /*
261 * sSS -> sSR Standard open.
262 * sSR -> sSR Retransmitted SYN/ACK.
263 * sES -> sIG Late retransmitted SYN/ACK?
264 * sFW -> sIG Might be SYN/ACK answering ignored SYN
265 * sCW -> sIG
266 * sLA -> sIG
267 * sTW -> sIG
268 * sCL -> sIG
269 */
270 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
271 /*fin*/ { sIV, sIV, sFW, sFW, sLA, sLA, sLA, sTW, sCL, sIV },
272 /*
273 * sSS -> sIV Server might not send FIN in this state.
274 * sSR -> sFW Close started.
275 * sES -> sFW
276 * sFW -> sLA FIN seen in both directions.
277 * sCW -> sLA
278 * sLA -> sLA Retransmitted FIN.
279 * sTW -> sTW
280 * sCL -> sCL
281 */
282 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
283 /*ack*/ { sIV, sIG, sSR, sES, sCW, sCW, sTW, sTW, sCL, sIV },
284 /*
285 * sSS -> sIG Might be a half-open connection.
286 * sSR -> sSR Might answer late resent SYN.
287 * sES -> sES :-)
288 * sFW -> sCW Normal close request answered by ACK.
289 * sCW -> sCW
290 * sLA -> sTW Last ACK detected.
291 * sTW -> sTW Retransmitted last ACK.
292 * sCL -> sCL
293 */
294 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
295 /*rst*/ { sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sIV },
296 /*none*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV }
297 }
298 };
299
300 static int tcp_pkt_to_tuple(const struct sk_buff *skb,
301 unsigned int dataoff,
302 struct nf_conntrack_tuple *tuple)
303 {
304 struct tcphdr _hdr, *hp;
305
306 /* Actually only need first 8 bytes. */
307 hp = skb_header_pointer(skb, dataoff, 8, &_hdr);
308 if (hp == NULL)
309 return 0;
310
311 tuple->src.u.tcp.port = hp->source;
312 tuple->dst.u.tcp.port = hp->dest;
313
314 return 1;
315 }
316
317 static int tcp_invert_tuple(struct nf_conntrack_tuple *tuple,
318 const struct nf_conntrack_tuple *orig)
319 {
320 tuple->src.u.tcp.port = orig->dst.u.tcp.port;
321 tuple->dst.u.tcp.port = orig->src.u.tcp.port;
322 return 1;
323 }
324
325 /* Print out the per-protocol part of the tuple. */
326 static int tcp_print_tuple(struct seq_file *s,
327 const struct nf_conntrack_tuple *tuple)
328 {
329 return seq_printf(s, "sport=%hu dport=%hu ",
330 ntohs(tuple->src.u.tcp.port),
331 ntohs(tuple->dst.u.tcp.port));
332 }
333
334 /* Print out the private part of the conntrack. */
335 static int tcp_print_conntrack(struct seq_file *s,
336 const struct nf_conn *conntrack)
337 {
338 enum tcp_conntrack state;
339
340 read_lock_bh(&tcp_lock);
341 state = conntrack->proto.tcp.state;
342 read_unlock_bh(&tcp_lock);
343
344 return seq_printf(s, "%s ", tcp_conntrack_names[state]);
345 }
346
347 static unsigned int get_conntrack_index(const struct tcphdr *tcph)
348 {
349 if (tcph->rst) return TCP_RST_SET;
350 else if (tcph->syn) return (tcph->ack ? TCP_SYNACK_SET : TCP_SYN_SET);
351 else if (tcph->fin) return TCP_FIN_SET;
352 else if (tcph->ack) return TCP_ACK_SET;
353 else return TCP_NONE_SET;
354 }
355
356 /* TCP connection tracking based on 'Real Stateful TCP Packet Filtering
357 in IP Filter' by Guido van Rooij.
358
359 http://www.nluug.nl/events/sane2000/papers.html
360 http://www.iae.nl/users/guido/papers/tcp_filtering.ps.gz
361
362 The boundaries and the conditions are changed according to RFC793:
363 the packet must intersect the window (i.e. segments may be
364 after the right or before the left edge) and thus receivers may ACK
365 segments after the right edge of the window.
366
367 td_maxend = max(sack + max(win,1)) seen in reply packets
368 td_maxwin = max(max(win, 1)) + (sack - ack) seen in sent packets
369 td_maxwin += seq + len - sender.td_maxend
370 if seq + len > sender.td_maxend
371 td_end = max(seq + len) seen in sent packets
372
373 I. Upper bound for valid data: seq <= sender.td_maxend
374 II. Lower bound for valid data: seq + len >= sender.td_end - receiver.td_maxwin
375 III. Upper bound for valid ack: sack <= receiver.td_end
376 IV. Lower bound for valid ack: ack >= receiver.td_end - MAXACKWINDOW
377
378 where sack is the highest right edge of sack block found in the packet.
379
380 The upper bound limit for a valid ack is not ignored -
381 we doesn't have to deal with fragments.
382 */
383
384 static inline __u32 segment_seq_plus_len(__u32 seq,
385 size_t len,
386 unsigned int dataoff,
387 struct tcphdr *tcph)
388 {
389 /* XXX Should I use payload length field in IP/IPv6 header ?
390 * - YK */
391 return (seq + len - dataoff - tcph->doff*4
392 + (tcph->syn ? 1 : 0) + (tcph->fin ? 1 : 0));
393 }
394
395 /* Fixme: what about big packets? */
396 #define MAXACKWINCONST 66000
397 #define MAXACKWINDOW(sender) \
398 ((sender)->td_maxwin > MAXACKWINCONST ? (sender)->td_maxwin \
399 : MAXACKWINCONST)
400
401 /*
402 * Simplified tcp_parse_options routine from tcp_input.c
403 */
404 static void tcp_options(const struct sk_buff *skb,
405 unsigned int dataoff,
406 struct tcphdr *tcph,
407 struct ip_ct_tcp_state *state)
408 {
409 unsigned char buff[(15 * 4) - sizeof(struct tcphdr)];
410 unsigned char *ptr;
411 int length = (tcph->doff*4) - sizeof(struct tcphdr);
412
413 if (!length)
414 return;
415
416 ptr = skb_header_pointer(skb, dataoff + sizeof(struct tcphdr),
417 length, buff);
418 BUG_ON(ptr == NULL);
419
420 state->td_scale =
421 state->flags = 0;
422
423 while (length > 0) {
424 int opcode=*ptr++;
425 int opsize;
426
427 switch (opcode) {
428 case TCPOPT_EOL:
429 return;
430 case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */
431 length--;
432 continue;
433 default:
434 opsize=*ptr++;
435 if (opsize < 2) /* "silly options" */
436 return;
437 if (opsize > length)
438 break; /* don't parse partial options */
439
440 if (opcode == TCPOPT_SACK_PERM
441 && opsize == TCPOLEN_SACK_PERM)
442 state->flags |= IP_CT_TCP_FLAG_SACK_PERM;
443 else if (opcode == TCPOPT_WINDOW
444 && opsize == TCPOLEN_WINDOW) {
445 state->td_scale = *(u_int8_t *)ptr;
446
447 if (state->td_scale > 14) {
448 /* See RFC1323 */
449 state->td_scale = 14;
450 }
451 state->flags |=
452 IP_CT_TCP_FLAG_WINDOW_SCALE;
453 }
454 ptr += opsize - 2;
455 length -= opsize;
456 }
457 }
458 }
459
460 static void tcp_sack(const struct sk_buff *skb, unsigned int dataoff,
461 struct tcphdr *tcph, __u32 *sack)
462 {
463 unsigned char buff[(15 * 4) - sizeof(struct tcphdr)];
464 unsigned char *ptr;
465 int length = (tcph->doff*4) - sizeof(struct tcphdr);
466 __u32 tmp;
467
468 if (!length)
469 return;
470
471 ptr = skb_header_pointer(skb, dataoff + sizeof(struct tcphdr),
472 length, buff);
473 BUG_ON(ptr == NULL);
474
475 /* Fast path for timestamp-only option */
476 if (length == TCPOLEN_TSTAMP_ALIGNED*4
477 && *(__u32 *)ptr ==
478 __constant_ntohl((TCPOPT_NOP << 24)
479 | (TCPOPT_NOP << 16)
480 | (TCPOPT_TIMESTAMP << 8)
481 | TCPOLEN_TIMESTAMP))
482 return;
483
484 while (length > 0) {
485 int opcode = *ptr++;
486 int opsize, i;
487
488 switch (opcode) {
489 case TCPOPT_EOL:
490 return;
491 case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */
492 length--;
493 continue;
494 default:
495 opsize = *ptr++;
496 if (opsize < 2) /* "silly options" */
497 return;
498 if (opsize > length)
499 break; /* don't parse partial options */
500
501 if (opcode == TCPOPT_SACK
502 && opsize >= (TCPOLEN_SACK_BASE
503 + TCPOLEN_SACK_PERBLOCK)
504 && !((opsize - TCPOLEN_SACK_BASE)
505 % TCPOLEN_SACK_PERBLOCK)) {
506 for (i = 0;
507 i < (opsize - TCPOLEN_SACK_BASE);
508 i += TCPOLEN_SACK_PERBLOCK) {
509 memcpy(&tmp, (__u32 *)(ptr + i) + 1,
510 sizeof(__u32));
511 tmp = ntohl(tmp);
512
513 if (after(tmp, *sack))
514 *sack = tmp;
515 }
516 return;
517 }
518 ptr += opsize - 2;
519 length -= opsize;
520 }
521 }
522 }
523
524 static int tcp_in_window(struct ip_ct_tcp *state,
525 enum ip_conntrack_dir dir,
526 unsigned int index,
527 const struct sk_buff *skb,
528 unsigned int dataoff,
529 struct tcphdr *tcph,
530 int pf)
531 {
532 struct ip_ct_tcp_state *sender = &state->seen[dir];
533 struct ip_ct_tcp_state *receiver = &state->seen[!dir];
534 __u32 seq, ack, sack, end, win, swin;
535 int res;
536
537 /*
538 * Get the required data from the packet.
539 */
540 seq = ntohl(tcph->seq);
541 ack = sack = ntohl(tcph->ack_seq);
542 win = ntohs(tcph->window);
543 end = segment_seq_plus_len(seq, skb->len, dataoff, tcph);
544
545 if (receiver->flags & IP_CT_TCP_FLAG_SACK_PERM)
546 tcp_sack(skb, dataoff, tcph, &sack);
547
548 DEBUGP("tcp_in_window: START\n");
549 DEBUGP("tcp_in_window: src=%u.%u.%u.%u:%hu dst=%u.%u.%u.%u:%hu "
550 "seq=%u ack=%u sack=%u win=%u end=%u\n",
551 NIPQUAD(iph->saddr), ntohs(tcph->source),
552 NIPQUAD(iph->daddr), ntohs(tcph->dest),
553 seq, ack, sack, win, end);
554 DEBUGP("tcp_in_window: sender end=%u maxend=%u maxwin=%u scale=%i "
555 "receiver end=%u maxend=%u maxwin=%u scale=%i\n",
556 sender->td_end, sender->td_maxend, sender->td_maxwin,
557 sender->td_scale,
558 receiver->td_end, receiver->td_maxend, receiver->td_maxwin,
559 receiver->td_scale);
560
561 if (sender->td_end == 0) {
562 /*
563 * Initialize sender data.
564 */
565 if (tcph->syn && tcph->ack) {
566 /*
567 * Outgoing SYN-ACK in reply to a SYN.
568 */
569 sender->td_end =
570 sender->td_maxend = end;
571 sender->td_maxwin = (win == 0 ? 1 : win);
572
573 tcp_options(skb, dataoff, tcph, sender);
574 /*
575 * RFC 1323:
576 * Both sides must send the Window Scale option
577 * to enable window scaling in either direction.
578 */
579 if (!(sender->flags & IP_CT_TCP_FLAG_WINDOW_SCALE
580 && receiver->flags & IP_CT_TCP_FLAG_WINDOW_SCALE))
581 sender->td_scale =
582 receiver->td_scale = 0;
583 } else {
584 /*
585 * We are in the middle of a connection,
586 * its history is lost for us.
587 * Let's try to use the data from the packet.
588 */
589 sender->td_end = end;
590 sender->td_maxwin = (win == 0 ? 1 : win);
591 sender->td_maxend = end + sender->td_maxwin;
592 }
593 } else if (((state->state == TCP_CONNTRACK_SYN_SENT
594 && dir == IP_CT_DIR_ORIGINAL)
595 || (state->state == TCP_CONNTRACK_SYN_RECV
596 && dir == IP_CT_DIR_REPLY))
597 && after(end, sender->td_end)) {
598 /*
599 * RFC 793: "if a TCP is reinitialized ... then it need
600 * not wait at all; it must only be sure to use sequence
601 * numbers larger than those recently used."
602 */
603 sender->td_end =
604 sender->td_maxend = end;
605 sender->td_maxwin = (win == 0 ? 1 : win);
606
607 tcp_options(skb, dataoff, tcph, sender);
608 }
609
610 if (!(tcph->ack)) {
611 /*
612 * If there is no ACK, just pretend it was set and OK.
613 */
614 ack = sack = receiver->td_end;
615 } else if (((tcp_flag_word(tcph) & (TCP_FLAG_ACK|TCP_FLAG_RST)) ==
616 (TCP_FLAG_ACK|TCP_FLAG_RST))
617 && (ack == 0)) {
618 /*
619 * Broken TCP stacks, that set ACK in RST packets as well
620 * with zero ack value.
621 */
622 ack = sack = receiver->td_end;
623 }
624
625 if (seq == end
626 && (!tcph->rst
627 || (seq == 0 && state->state == TCP_CONNTRACK_SYN_SENT)))
628 /*
629 * Packets contains no data: we assume it is valid
630 * and check the ack value only.
631 * However RST segments are always validated by their
632 * SEQ number, except when seq == 0 (reset sent answering
633 * SYN.
634 */
635 seq = end = sender->td_end;
636
637 DEBUGP("tcp_in_window: src=%u.%u.%u.%u:%hu dst=%u.%u.%u.%u:%hu "
638 "seq=%u ack=%u sack =%u win=%u end=%u\n",
639 NIPQUAD(iph->saddr), ntohs(tcph->source),
640 NIPQUAD(iph->daddr), ntohs(tcph->dest),
641 seq, ack, sack, win, end);
642 DEBUGP("tcp_in_window: sender end=%u maxend=%u maxwin=%u scale=%i "
643 "receiver end=%u maxend=%u maxwin=%u scale=%i\n",
644 sender->td_end, sender->td_maxend, sender->td_maxwin,
645 sender->td_scale,
646 receiver->td_end, receiver->td_maxend, receiver->td_maxwin,
647 receiver->td_scale);
648
649 DEBUGP("tcp_in_window: I=%i II=%i III=%i IV=%i\n",
650 before(seq, sender->td_maxend + 1),
651 after(end, sender->td_end - receiver->td_maxwin - 1),
652 before(sack, receiver->td_end + 1),
653 after(ack, receiver->td_end - MAXACKWINDOW(sender)));
654
655 if (sender->loose || receiver->loose ||
656 (before(seq, sender->td_maxend + 1) &&
657 after(end, sender->td_end - receiver->td_maxwin - 1) &&
658 before(sack, receiver->td_end + 1) &&
659 after(ack, receiver->td_end - MAXACKWINDOW(sender)))) {
660 /*
661 * Take into account window scaling (RFC 1323).
662 */
663 if (!tcph->syn)
664 win <<= sender->td_scale;
665
666 /*
667 * Update sender data.
668 */
669 swin = win + (sack - ack);
670 if (sender->td_maxwin < swin)
671 sender->td_maxwin = swin;
672 if (after(end, sender->td_end))
673 sender->td_end = end;
674 /*
675 * Update receiver data.
676 */
677 if (after(end, sender->td_maxend))
678 receiver->td_maxwin += end - sender->td_maxend;
679 if (after(sack + win, receiver->td_maxend - 1)) {
680 receiver->td_maxend = sack + win;
681 if (win == 0)
682 receiver->td_maxend++;
683 }
684
685 /*
686 * Check retransmissions.
687 */
688 if (index == TCP_ACK_SET) {
689 if (state->last_dir == dir
690 && state->last_seq == seq
691 && state->last_ack == ack
692 && state->last_end == end)
693 state->retrans++;
694 else {
695 state->last_dir = dir;
696 state->last_seq = seq;
697 state->last_ack = ack;
698 state->last_end = end;
699 state->retrans = 0;
700 }
701 }
702 /*
703 * Close the window of disabled window tracking :-)
704 */
705 if (sender->loose)
706 sender->loose--;
707
708 res = 1;
709 } else {
710 if (LOG_INVALID(IPPROTO_TCP))
711 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
712 "nf_ct_tcp: %s ",
713 before(seq, sender->td_maxend + 1) ?
714 after(end, sender->td_end - receiver->td_maxwin - 1) ?
715 before(sack, receiver->td_end + 1) ?
716 after(ack, receiver->td_end - MAXACKWINDOW(sender)) ? "BUG"
717 : "ACK is under the lower bound (possible overly delayed ACK)"
718 : "ACK is over the upper bound (ACKed data not seen yet)"
719 : "SEQ is under the lower bound (already ACKed data retransmitted)"
720 : "SEQ is over the upper bound (over the window of the receiver)");
721
722 res = nf_ct_tcp_be_liberal;
723 }
724
725 DEBUGP("tcp_in_window: res=%i sender end=%u maxend=%u maxwin=%u "
726 "receiver end=%u maxend=%u maxwin=%u\n",
727 res, sender->td_end, sender->td_maxend, sender->td_maxwin,
728 receiver->td_end, receiver->td_maxend, receiver->td_maxwin);
729
730 return res;
731 }
732
733 #ifdef CONFIG_IP_NF_NAT_NEEDED
734 /* Update sender->td_end after NAT successfully mangled the packet */
735 /* Caller must linearize skb at tcp header. */
736 void nf_conntrack_tcp_update(struct sk_buff *skb,
737 unsigned int dataoff,
738 struct nf_conn *conntrack,
739 int dir)
740 {
741 struct tcphdr *tcph = (void *)skb->data + dataoff;
742 __u32 end;
743 #ifdef DEBUGP_VARS
744 struct ip_ct_tcp_state *sender = &conntrack->proto.tcp.seen[dir];
745 struct ip_ct_tcp_state *receiver = &conntrack->proto.tcp.seen[!dir];
746 #endif
747
748 end = segment_seq_plus_len(ntohl(tcph->seq), skb->len, dataoff, tcph);
749
750 write_lock_bh(&tcp_lock);
751 /*
752 * We have to worry for the ack in the reply packet only...
753 */
754 if (after(end, conntrack->proto.tcp.seen[dir].td_end))
755 conntrack->proto.tcp.seen[dir].td_end = end;
756 conntrack->proto.tcp.last_end = end;
757 write_unlock_bh(&tcp_lock);
758 DEBUGP("tcp_update: sender end=%u maxend=%u maxwin=%u scale=%i "
759 "receiver end=%u maxend=%u maxwin=%u scale=%i\n",
760 sender->td_end, sender->td_maxend, sender->td_maxwin,
761 sender->td_scale,
762 receiver->td_end, receiver->td_maxend, receiver->td_maxwin,
763 receiver->td_scale);
764 }
765
766 #endif
767
768 #define TH_FIN 0x01
769 #define TH_SYN 0x02
770 #define TH_RST 0x04
771 #define TH_PUSH 0x08
772 #define TH_ACK 0x10
773 #define TH_URG 0x20
774 #define TH_ECE 0x40
775 #define TH_CWR 0x80
776
777 /* table of valid flag combinations - ECE and CWR are always valid */
778 static u8 tcp_valid_flags[(TH_FIN|TH_SYN|TH_RST|TH_PUSH|TH_ACK|TH_URG) + 1] =
779 {
780 [TH_SYN] = 1,
781 [TH_SYN|TH_ACK] = 1,
782 [TH_SYN|TH_PUSH] = 1,
783 [TH_SYN|TH_ACK|TH_PUSH] = 1,
784 [TH_RST] = 1,
785 [TH_RST|TH_ACK] = 1,
786 [TH_RST|TH_ACK|TH_PUSH] = 1,
787 [TH_FIN|TH_ACK] = 1,
788 [TH_ACK] = 1,
789 [TH_ACK|TH_PUSH] = 1,
790 [TH_ACK|TH_URG] = 1,
791 [TH_ACK|TH_URG|TH_PUSH] = 1,
792 [TH_FIN|TH_ACK|TH_PUSH] = 1,
793 [TH_FIN|TH_ACK|TH_URG] = 1,
794 [TH_FIN|TH_ACK|TH_URG|TH_PUSH] = 1,
795 };
796
797 /* Protect conntrack agaist broken packets. Code taken from ipt_unclean.c. */
798 static int tcp_error(struct sk_buff *skb,
799 unsigned int dataoff,
800 enum ip_conntrack_info *ctinfo,
801 int pf,
802 unsigned int hooknum)
803 {
804 struct tcphdr _tcph, *th;
805 unsigned int tcplen = skb->len - dataoff;
806 u_int8_t tcpflags;
807
808 /* Smaller that minimal TCP header? */
809 th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph);
810 if (th == NULL) {
811 if (LOG_INVALID(IPPROTO_TCP))
812 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
813 "nf_ct_tcp: short packet ");
814 return -NF_ACCEPT;
815 }
816
817 /* Not whole TCP header or malformed packet */
818 if (th->doff*4 < sizeof(struct tcphdr) || tcplen < th->doff*4) {
819 if (LOG_INVALID(IPPROTO_TCP))
820 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
821 "nf_ct_tcp: truncated/malformed packet ");
822 return -NF_ACCEPT;
823 }
824
825 /* Checksum invalid? Ignore.
826 * We skip checking packets on the outgoing path
827 * because the semantic of CHECKSUM_HW is different there
828 * and moreover root might send raw packets.
829 */
830 /* FIXME: Source route IP option packets --RR */
831 if (nf_conntrack_checksum &&
832 ((pf == PF_INET && hooknum == NF_IP_PRE_ROUTING) ||
833 (pf == PF_INET6 && hooknum == NF_IP6_PRE_ROUTING)) &&
834 nf_checksum(skb, hooknum, dataoff, IPPROTO_TCP, pf)) {
835 if (LOG_INVALID(IPPROTO_TCP))
836 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
837 "nf_ct_tcp: bad TCP checksum ");
838 return -NF_ACCEPT;
839 }
840
841 /* Check TCP flags. */
842 tcpflags = (((u_int8_t *)th)[13] & ~(TH_ECE|TH_CWR));
843 if (!tcp_valid_flags[tcpflags]) {
844 if (LOG_INVALID(IPPROTO_TCP))
845 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
846 "nf_ct_tcp: invalid TCP flag combination ");
847 return -NF_ACCEPT;
848 }
849
850 return NF_ACCEPT;
851 }
852
853 /* Returns verdict for packet, or -1 for invalid. */
854 static int tcp_packet(struct nf_conn *conntrack,
855 const struct sk_buff *skb,
856 unsigned int dataoff,
857 enum ip_conntrack_info ctinfo,
858 int pf,
859 unsigned int hooknum)
860 {
861 enum tcp_conntrack new_state, old_state;
862 enum ip_conntrack_dir dir;
863 struct tcphdr *th, _tcph;
864 unsigned long timeout;
865 unsigned int index;
866
867 th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph);
868 BUG_ON(th == NULL);
869
870 write_lock_bh(&tcp_lock);
871 old_state = conntrack->proto.tcp.state;
872 dir = CTINFO2DIR(ctinfo);
873 index = get_conntrack_index(th);
874 new_state = tcp_conntracks[dir][index][old_state];
875
876 switch (new_state) {
877 case TCP_CONNTRACK_IGNORE:
878 /* Ignored packets:
879 *
880 * a) SYN in ORIGINAL
881 * b) SYN/ACK in REPLY
882 * c) ACK in reply direction after initial SYN in original.
883 */
884 if (index == TCP_SYNACK_SET
885 && conntrack->proto.tcp.last_index == TCP_SYN_SET
886 && conntrack->proto.tcp.last_dir != dir
887 && ntohl(th->ack_seq) ==
888 conntrack->proto.tcp.last_end) {
889 /* This SYN/ACK acknowledges a SYN that we earlier
890 * ignored as invalid. This means that the client and
891 * the server are both in sync, while the firewall is
892 * not. We kill this session and block the SYN/ACK so
893 * that the client cannot but retransmit its SYN and
894 * thus initiate a clean new session.
895 */
896 write_unlock_bh(&tcp_lock);
897 if (LOG_INVALID(IPPROTO_TCP))
898 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
899 "nf_ct_tcp: killing out of sync session ");
900 if (del_timer(&conntrack->timeout))
901 conntrack->timeout.function((unsigned long)
902 conntrack);
903 return -NF_DROP;
904 }
905 conntrack->proto.tcp.last_index = index;
906 conntrack->proto.tcp.last_dir = dir;
907 conntrack->proto.tcp.last_seq = ntohl(th->seq);
908 conntrack->proto.tcp.last_end =
909 segment_seq_plus_len(ntohl(th->seq), skb->len, dataoff, th);
910
911 write_unlock_bh(&tcp_lock);
912 if (LOG_INVALID(IPPROTO_TCP))
913 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
914 "nf_ct_tcp: invalid packed ignored ");
915 return NF_ACCEPT;
916 case TCP_CONNTRACK_MAX:
917 /* Invalid packet */
918 DEBUGP("nf_ct_tcp: Invalid dir=%i index=%u ostate=%u\n",
919 dir, get_conntrack_index(th),
920 old_state);
921 write_unlock_bh(&tcp_lock);
922 if (LOG_INVALID(IPPROTO_TCP))
923 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
924 "nf_ct_tcp: invalid state ");
925 return -NF_ACCEPT;
926 case TCP_CONNTRACK_SYN_SENT:
927 if (old_state < TCP_CONNTRACK_TIME_WAIT)
928 break;
929 if ((conntrack->proto.tcp.seen[dir].flags &
930 IP_CT_TCP_FLAG_CLOSE_INIT)
931 || after(ntohl(th->seq),
932 conntrack->proto.tcp.seen[dir].td_end)) {
933 /* Attempt to reopen a closed connection.
934 * Delete this connection and look up again. */
935 write_unlock_bh(&tcp_lock);
936 if (del_timer(&conntrack->timeout))
937 conntrack->timeout.function((unsigned long)
938 conntrack);
939 return -NF_REPEAT;
940 } else {
941 write_unlock_bh(&tcp_lock);
942 if (LOG_INVALID(IPPROTO_TCP))
943 nf_log_packet(pf, 0, skb, NULL, NULL,
944 NULL, "nf_ct_tcp: invalid SYN");
945 return -NF_ACCEPT;
946 }
947 case TCP_CONNTRACK_CLOSE:
948 if (index == TCP_RST_SET
949 && ((test_bit(IPS_SEEN_REPLY_BIT, &conntrack->status)
950 && conntrack->proto.tcp.last_index == TCP_SYN_SET)
951 || (!test_bit(IPS_ASSURED_BIT, &conntrack->status)
952 && conntrack->proto.tcp.last_index == TCP_ACK_SET))
953 && ntohl(th->ack_seq) == conntrack->proto.tcp.last_end) {
954 /* RST sent to invalid SYN or ACK we had let through
955 * at a) and c) above:
956 *
957 * a) SYN was in window then
958 * c) we hold a half-open connection.
959 *
960 * Delete our connection entry.
961 * We skip window checking, because packet might ACK
962 * segments we ignored. */
963 goto in_window;
964 }
965 /* Just fall through */
966 default:
967 /* Keep compilers happy. */
968 break;
969 }
970
971 if (!tcp_in_window(&conntrack->proto.tcp, dir, index,
972 skb, dataoff, th, pf)) {
973 write_unlock_bh(&tcp_lock);
974 return -NF_ACCEPT;
975 }
976 in_window:
977 /* From now on we have got in-window packets */
978 conntrack->proto.tcp.last_index = index;
979
980 DEBUGP("tcp_conntracks: src=%u.%u.%u.%u:%hu dst=%u.%u.%u.%u:%hu "
981 "syn=%i ack=%i fin=%i rst=%i old=%i new=%i\n",
982 NIPQUAD(iph->saddr), ntohs(th->source),
983 NIPQUAD(iph->daddr), ntohs(th->dest),
984 (th->syn ? 1 : 0), (th->ack ? 1 : 0),
985 (th->fin ? 1 : 0), (th->rst ? 1 : 0),
986 old_state, new_state);
987
988 conntrack->proto.tcp.state = new_state;
989 if (old_state != new_state
990 && (new_state == TCP_CONNTRACK_FIN_WAIT
991 || new_state == TCP_CONNTRACK_CLOSE))
992 conntrack->proto.tcp.seen[dir].flags |= IP_CT_TCP_FLAG_CLOSE_INIT;
993 timeout = conntrack->proto.tcp.retrans >= nf_ct_tcp_max_retrans
994 && *tcp_timeouts[new_state] > nf_ct_tcp_timeout_max_retrans
995 ? nf_ct_tcp_timeout_max_retrans : *tcp_timeouts[new_state];
996 write_unlock_bh(&tcp_lock);
997
998 nf_conntrack_event_cache(IPCT_PROTOINFO_VOLATILE, skb);
999 if (new_state != old_state)
1000 nf_conntrack_event_cache(IPCT_PROTOINFO, skb);
1001
1002 if (!test_bit(IPS_SEEN_REPLY_BIT, &conntrack->status)) {
1003 /* If only reply is a RST, we can consider ourselves not to
1004 have an established connection: this is a fairly common
1005 problem case, so we can delete the conntrack
1006 immediately. --RR */
1007 if (th->rst) {
1008 if (del_timer(&conntrack->timeout))
1009 conntrack->timeout.function((unsigned long)
1010 conntrack);
1011 return NF_ACCEPT;
1012 }
1013 } else if (!test_bit(IPS_ASSURED_BIT, &conntrack->status)
1014 && (old_state == TCP_CONNTRACK_SYN_RECV
1015 || old_state == TCP_CONNTRACK_ESTABLISHED)
1016 && new_state == TCP_CONNTRACK_ESTABLISHED) {
1017 /* Set ASSURED if we see see valid ack in ESTABLISHED
1018 after SYN_RECV or a valid answer for a picked up
1019 connection. */
1020 set_bit(IPS_ASSURED_BIT, &conntrack->status);
1021 nf_conntrack_event_cache(IPCT_STATUS, skb);
1022 }
1023 nf_ct_refresh_acct(conntrack, ctinfo, skb, timeout);
1024
1025 return NF_ACCEPT;
1026 }
1027
1028 /* Called when a new connection for this protocol found. */
1029 static int tcp_new(struct nf_conn *conntrack,
1030 const struct sk_buff *skb,
1031 unsigned int dataoff)
1032 {
1033 enum tcp_conntrack new_state;
1034 struct tcphdr *th, _tcph;
1035 #ifdef DEBUGP_VARS
1036 struct ip_ct_tcp_state *sender = &conntrack->proto.tcp.seen[0];
1037 struct ip_ct_tcp_state *receiver = &conntrack->proto.tcp.seen[1];
1038 #endif
1039
1040 th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph);
1041 BUG_ON(th == NULL);
1042
1043 /* Don't need lock here: this conntrack not in circulation yet */
1044 new_state
1045 = tcp_conntracks[0][get_conntrack_index(th)]
1046 [TCP_CONNTRACK_NONE];
1047
1048 /* Invalid: delete conntrack */
1049 if (new_state >= TCP_CONNTRACK_MAX) {
1050 DEBUGP("nf_ct_tcp: invalid new deleting.\n");
1051 return 0;
1052 }
1053
1054 if (new_state == TCP_CONNTRACK_SYN_SENT) {
1055 /* SYN packet */
1056 conntrack->proto.tcp.seen[0].td_end =
1057 segment_seq_plus_len(ntohl(th->seq), skb->len,
1058 dataoff, th);
1059 conntrack->proto.tcp.seen[0].td_maxwin = ntohs(th->window);
1060 if (conntrack->proto.tcp.seen[0].td_maxwin == 0)
1061 conntrack->proto.tcp.seen[0].td_maxwin = 1;
1062 conntrack->proto.tcp.seen[0].td_maxend =
1063 conntrack->proto.tcp.seen[0].td_end;
1064
1065 tcp_options(skb, dataoff, th, &conntrack->proto.tcp.seen[0]);
1066 conntrack->proto.tcp.seen[1].flags = 0;
1067 conntrack->proto.tcp.seen[0].loose =
1068 conntrack->proto.tcp.seen[1].loose = 0;
1069 } else if (nf_ct_tcp_loose == 0) {
1070 /* Don't try to pick up connections. */
1071 return 0;
1072 } else {
1073 /*
1074 * We are in the middle of a connection,
1075 * its history is lost for us.
1076 * Let's try to use the data from the packet.
1077 */
1078 conntrack->proto.tcp.seen[0].td_end =
1079 segment_seq_plus_len(ntohl(th->seq), skb->len,
1080 dataoff, th);
1081 conntrack->proto.tcp.seen[0].td_maxwin = ntohs(th->window);
1082 if (conntrack->proto.tcp.seen[0].td_maxwin == 0)
1083 conntrack->proto.tcp.seen[0].td_maxwin = 1;
1084 conntrack->proto.tcp.seen[0].td_maxend =
1085 conntrack->proto.tcp.seen[0].td_end +
1086 conntrack->proto.tcp.seen[0].td_maxwin;
1087 conntrack->proto.tcp.seen[0].td_scale = 0;
1088
1089 /* We assume SACK. Should we assume window scaling too? */
1090 conntrack->proto.tcp.seen[0].flags =
1091 conntrack->proto.tcp.seen[1].flags = IP_CT_TCP_FLAG_SACK_PERM;
1092 conntrack->proto.tcp.seen[0].loose =
1093 conntrack->proto.tcp.seen[1].loose = nf_ct_tcp_loose;
1094 }
1095
1096 conntrack->proto.tcp.seen[1].td_end = 0;
1097 conntrack->proto.tcp.seen[1].td_maxend = 0;
1098 conntrack->proto.tcp.seen[1].td_maxwin = 1;
1099 conntrack->proto.tcp.seen[1].td_scale = 0;
1100
1101 /* tcp_packet will set them */
1102 conntrack->proto.tcp.state = TCP_CONNTRACK_NONE;
1103 conntrack->proto.tcp.last_index = TCP_NONE_SET;
1104
1105 DEBUGP("tcp_new: sender end=%u maxend=%u maxwin=%u scale=%i "
1106 "receiver end=%u maxend=%u maxwin=%u scale=%i\n",
1107 sender->td_end, sender->td_maxend, sender->td_maxwin,
1108 sender->td_scale,
1109 receiver->td_end, receiver->td_maxend, receiver->td_maxwin,
1110 receiver->td_scale);
1111 return 1;
1112 }
1113
1114 #if defined(CONFIG_NF_CT_NETLINK) || \
1115 defined(CONFIG_NF_CT_NETLINK_MODULE)
1116
1117 #include <linux/netfilter/nfnetlink.h>
1118 #include <linux/netfilter/nfnetlink_conntrack.h>
1119
1120 static int tcp_to_nfattr(struct sk_buff *skb, struct nfattr *nfa,
1121 const struct nf_conn *ct)
1122 {
1123 struct nfattr *nest_parms;
1124
1125 read_lock_bh(&tcp_lock);
1126 nest_parms = NFA_NEST(skb, CTA_PROTOINFO_TCP);
1127 NFA_PUT(skb, CTA_PROTOINFO_TCP_STATE, sizeof(u_int8_t),
1128 &ct->proto.tcp.state);
1129 read_unlock_bh(&tcp_lock);
1130
1131 NFA_NEST_END(skb, nest_parms);
1132
1133 return 0;
1134
1135 nfattr_failure:
1136 read_unlock_bh(&tcp_lock);
1137 return -1;
1138 }
1139
1140 static const size_t cta_min_tcp[CTA_PROTOINFO_TCP_MAX] = {
1141 [CTA_PROTOINFO_TCP_STATE-1] = sizeof(u_int8_t),
1142 };
1143
1144 static int nfattr_to_tcp(struct nfattr *cda[], struct nf_conn *ct)
1145 {
1146 struct nfattr *attr = cda[CTA_PROTOINFO_TCP-1];
1147 struct nfattr *tb[CTA_PROTOINFO_TCP_MAX];
1148
1149 /* updates could not contain anything about the private
1150 * protocol info, in that case skip the parsing */
1151 if (!attr)
1152 return 0;
1153
1154 nfattr_parse_nested(tb, CTA_PROTOINFO_TCP_MAX, attr);
1155
1156 if (nfattr_bad_size(tb, CTA_PROTOINFO_TCP_MAX, cta_min_tcp))
1157 return -EINVAL;
1158
1159 if (!tb[CTA_PROTOINFO_TCP_STATE-1])
1160 return -EINVAL;
1161
1162 write_lock_bh(&tcp_lock);
1163 ct->proto.tcp.state =
1164 *(u_int8_t *)NFA_DATA(tb[CTA_PROTOINFO_TCP_STATE-1]);
1165 write_unlock_bh(&tcp_lock);
1166
1167 return 0;
1168 }
1169 #endif
1170
1171 struct nf_conntrack_protocol nf_conntrack_protocol_tcp4 =
1172 {
1173 .l3proto = PF_INET,
1174 .proto = IPPROTO_TCP,
1175 .name = "tcp",
1176 .pkt_to_tuple = tcp_pkt_to_tuple,
1177 .invert_tuple = tcp_invert_tuple,
1178 .print_tuple = tcp_print_tuple,
1179 .print_conntrack = tcp_print_conntrack,
1180 .packet = tcp_packet,
1181 .new = tcp_new,
1182 .error = tcp_error,
1183 #if defined(CONFIG_NF_CT_NETLINK) || \
1184 defined(CONFIG_NF_CT_NETLINK_MODULE)
1185 .to_nfattr = tcp_to_nfattr,
1186 .from_nfattr = nfattr_to_tcp,
1187 .tuple_to_nfattr = nf_ct_port_tuple_to_nfattr,
1188 .nfattr_to_tuple = nf_ct_port_nfattr_to_tuple,
1189 #endif
1190 };
1191
1192 struct nf_conntrack_protocol nf_conntrack_protocol_tcp6 =
1193 {
1194 .l3proto = PF_INET6,
1195 .proto = IPPROTO_TCP,
1196 .name = "tcp",
1197 .pkt_to_tuple = tcp_pkt_to_tuple,
1198 .invert_tuple = tcp_invert_tuple,
1199 .print_tuple = tcp_print_tuple,
1200 .print_conntrack = tcp_print_conntrack,
1201 .packet = tcp_packet,
1202 .new = tcp_new,
1203 .error = tcp_error,
1204 #if defined(CONFIG_NF_CT_NETLINK) || \
1205 defined(CONFIG_NF_CT_NETLINK_MODULE)
1206 .to_nfattr = tcp_to_nfattr,
1207 .from_nfattr = nfattr_to_tcp,
1208 .tuple_to_nfattr = nf_ct_port_tuple_to_nfattr,
1209 .nfattr_to_tuple = nf_ct_port_nfattr_to_tuple,
1210 #endif
1211 };
1212
1213 EXPORT_SYMBOL(nf_conntrack_protocol_tcp4);
1214 EXPORT_SYMBOL(nf_conntrack_protocol_tcp6);
Linux kernel - Deliverables
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