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[NETFILTER]: ctnetlink: use netlink attribute helpers
[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
9 #include <linux/types.h>
10 #include <linux/timer.h>
11 #include <linux/module.h>
12 #include <linux/in.h>
13 #include <linux/tcp.h>
14 #include <linux/spinlock.h>
15 #include <linux/skbuff.h>
16 #include <linux/ipv6.h>
17 #include <net/ip6_checksum.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
28 /* Protects conntrack->proto.tcp */
29 static DEFINE_RWLOCK(tcp_lock);
30
31 /* "Be conservative in what you do,
32 be liberal in what you accept from others."
33 If it's non-zero, we mark only out of window RST segments as INVALID. */
34 static int nf_ct_tcp_be_liberal __read_mostly = 0;
35
36 /* If it is set to zero, we disable picking up already established
37 connections. */
38 static int nf_ct_tcp_loose __read_mostly = 1;
39
40 /* Max number of the retransmitted packets without receiving an (acceptable)
41 ACK from the destination. If this number is reached, a shorter timer
42 will be started. */
43 static int nf_ct_tcp_max_retrans __read_mostly = 3;
44
45 /* FIXME: Examine ipfilter's timeouts and conntrack transitions more
46 closely. They're more complex. --RR */
47
48 static const char *tcp_conntrack_names[] = {
49 "NONE",
50 "SYN_SENT",
51 "SYN_RECV",
52 "ESTABLISHED",
53 "FIN_WAIT",
54 "CLOSE_WAIT",
55 "LAST_ACK",
56 "TIME_WAIT",
57 "CLOSE",
58 "LISTEN"
59 };
60
61 #define SECS * HZ
62 #define MINS * 60 SECS
63 #define HOURS * 60 MINS
64 #define DAYS * 24 HOURS
65
66 static unsigned int nf_ct_tcp_timeout_syn_sent __read_mostly = 2 MINS;
67 static unsigned int nf_ct_tcp_timeout_syn_recv __read_mostly = 60 SECS;
68 static unsigned int nf_ct_tcp_timeout_established __read_mostly = 5 DAYS;
69 static unsigned int nf_ct_tcp_timeout_fin_wait __read_mostly = 2 MINS;
70 static unsigned int nf_ct_tcp_timeout_close_wait __read_mostly = 60 SECS;
71 static unsigned int nf_ct_tcp_timeout_last_ack __read_mostly = 30 SECS;
72 static unsigned int nf_ct_tcp_timeout_time_wait __read_mostly = 2 MINS;
73 static unsigned int nf_ct_tcp_timeout_close __read_mostly = 10 SECS;
74
75 /* RFC1122 says the R2 limit should be at least 100 seconds.
76 Linux uses 15 packets as limit, which corresponds
77 to ~13-30min depending on RTO. */
78 static unsigned int nf_ct_tcp_timeout_max_retrans __read_mostly = 5 MINS;
79
80 static unsigned int * tcp_timeouts[] = {
81 NULL, /* TCP_CONNTRACK_NONE */
82 &nf_ct_tcp_timeout_syn_sent, /* TCP_CONNTRACK_SYN_SENT, */
83 &nf_ct_tcp_timeout_syn_recv, /* TCP_CONNTRACK_SYN_RECV, */
84 &nf_ct_tcp_timeout_established, /* TCP_CONNTRACK_ESTABLISHED, */
85 &nf_ct_tcp_timeout_fin_wait, /* TCP_CONNTRACK_FIN_WAIT, */
86 &nf_ct_tcp_timeout_close_wait, /* TCP_CONNTRACK_CLOSE_WAIT, */
87 &nf_ct_tcp_timeout_last_ack, /* TCP_CONNTRACK_LAST_ACK, */
88 &nf_ct_tcp_timeout_time_wait, /* TCP_CONNTRACK_TIME_WAIT, */
89 &nf_ct_tcp_timeout_close, /* TCP_CONNTRACK_CLOSE, */
90 NULL, /* TCP_CONNTRACK_LISTEN */
91 };
92
93 #define sNO TCP_CONNTRACK_NONE
94 #define sSS TCP_CONNTRACK_SYN_SENT
95 #define sSR TCP_CONNTRACK_SYN_RECV
96 #define sES TCP_CONNTRACK_ESTABLISHED
97 #define sFW TCP_CONNTRACK_FIN_WAIT
98 #define sCW TCP_CONNTRACK_CLOSE_WAIT
99 #define sLA TCP_CONNTRACK_LAST_ACK
100 #define sTW TCP_CONNTRACK_TIME_WAIT
101 #define sCL TCP_CONNTRACK_CLOSE
102 #define sLI TCP_CONNTRACK_LISTEN
103 #define sIV TCP_CONNTRACK_MAX
104 #define sIG TCP_CONNTRACK_IGNORE
105
106 /* What TCP flags are set from RST/SYN/FIN/ACK. */
107 enum tcp_bit_set {
108 TCP_SYN_SET,
109 TCP_SYNACK_SET,
110 TCP_FIN_SET,
111 TCP_ACK_SET,
112 TCP_RST_SET,
113 TCP_NONE_SET,
114 };
115
116 /*
117 * The TCP state transition table needs a few words...
118 *
119 * We are the man in the middle. All the packets go through us
120 * but might get lost in transit to the destination.
121 * It is assumed that the destinations can't receive segments
122 * we haven't seen.
123 *
124 * The checked segment is in window, but our windows are *not*
125 * equivalent with the ones of the sender/receiver. We always
126 * try to guess the state of the current sender.
127 *
128 * The meaning of the states are:
129 *
130 * NONE: initial state
131 * SYN_SENT: SYN-only packet seen
132 * SYN_RECV: SYN-ACK packet seen
133 * ESTABLISHED: ACK packet seen
134 * FIN_WAIT: FIN packet seen
135 * CLOSE_WAIT: ACK seen (after FIN)
136 * LAST_ACK: FIN seen (after FIN)
137 * TIME_WAIT: last ACK seen
138 * CLOSE: closed connection
139 *
140 * LISTEN state is not used.
141 *
142 * Packets marked as IGNORED (sIG):
143 * if they may be either invalid or valid
144 * and the receiver may send back a connection
145 * closing RST or a SYN/ACK.
146 *
147 * Packets marked as INVALID (sIV):
148 * if they are invalid
149 * or we do not support the request (simultaneous open)
150 */
151 static enum tcp_conntrack tcp_conntracks[2][6][TCP_CONNTRACK_MAX] = {
152 {
153 /* ORIGINAL */
154 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
155 /*syn*/ { sSS, sSS, sIG, sIG, sIG, sIG, sIG, sSS, sSS, sIV },
156 /*
157 * sNO -> sSS Initialize a new connection
158 * sSS -> sSS Retransmitted SYN
159 * sSR -> sIG Late retransmitted SYN?
160 * sES -> sIG Error: SYNs in window outside the SYN_SENT state
161 * are errors. Receiver will reply with RST
162 * and close the connection.
163 * Or we are not in sync and hold a dead connection.
164 * sFW -> sIG
165 * sCW -> sIG
166 * sLA -> sIG
167 * sTW -> sSS Reopened connection (RFC 1122).
168 * sCL -> sSS
169 */
170 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
171 /*synack*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV },
172 /*
173 * A SYN/ACK from the client is always invalid:
174 * - either it tries to set up a simultaneous open, which is
175 * not supported;
176 * - or the firewall has just been inserted between the two hosts
177 * during the session set-up. The SYN will be retransmitted
178 * by the true client (or it'll time out).
179 */
180 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
181 /*fin*/ { sIV, sIV, sFW, sFW, sLA, sLA, sLA, sTW, sCL, sIV },
182 /*
183 * sNO -> sIV Too late and no reason to do anything...
184 * sSS -> sIV Client migth not send FIN in this state:
185 * we enforce waiting for a SYN/ACK reply first.
186 * sSR -> sFW Close started.
187 * sES -> sFW
188 * sFW -> sLA FIN seen in both directions, waiting for
189 * the last ACK.
190 * Migth be a retransmitted FIN as well...
191 * sCW -> sLA
192 * sLA -> sLA Retransmitted FIN. Remain in the same state.
193 * sTW -> sTW
194 * sCL -> sCL
195 */
196 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
197 /*ack*/ { sES, sIV, sES, sES, sCW, sCW, sTW, sTW, sCL, sIV },
198 /*
199 * sNO -> sES Assumed.
200 * sSS -> sIV ACK is invalid: we haven't seen a SYN/ACK yet.
201 * sSR -> sES Established state is reached.
202 * sES -> sES :-)
203 * sFW -> sCW Normal close request answered by ACK.
204 * sCW -> sCW
205 * sLA -> sTW Last ACK detected.
206 * sTW -> sTW Retransmitted last ACK. Remain in the same state.
207 * sCL -> sCL
208 */
209 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
210 /*rst*/ { sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sIV },
211 /*none*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV }
212 },
213 {
214 /* REPLY */
215 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
216 /*syn*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV },
217 /*
218 * sNO -> sIV Never reached.
219 * sSS -> sIV Simultaneous open, not supported
220 * sSR -> sIV Simultaneous open, not supported.
221 * sES -> sIV Server may not initiate a connection.
222 * sFW -> sIV
223 * sCW -> sIV
224 * sLA -> sIV
225 * sTW -> sIV Reopened connection, but server may not do it.
226 * sCL -> sIV
227 */
228 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
229 /*synack*/ { sIV, sSR, sSR, sIG, sIG, sIG, sIG, sIG, sIG, sIV },
230 /*
231 * sSS -> sSR Standard open.
232 * sSR -> sSR Retransmitted SYN/ACK.
233 * sES -> sIG Late retransmitted SYN/ACK?
234 * sFW -> sIG Might be SYN/ACK answering ignored SYN
235 * sCW -> sIG
236 * sLA -> sIG
237 * sTW -> sIG
238 * sCL -> sIG
239 */
240 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
241 /*fin*/ { sIV, sIV, sFW, sFW, sLA, sLA, sLA, sTW, sCL, sIV },
242 /*
243 * sSS -> sIV Server might not send FIN in this state.
244 * sSR -> sFW Close started.
245 * sES -> sFW
246 * sFW -> sLA FIN seen in both directions.
247 * sCW -> sLA
248 * sLA -> sLA Retransmitted FIN.
249 * sTW -> sTW
250 * sCL -> sCL
251 */
252 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
253 /*ack*/ { sIV, sIG, sSR, sES, sCW, sCW, sTW, sTW, sCL, sIV },
254 /*
255 * sSS -> sIG Might be a half-open connection.
256 * sSR -> sSR Might answer late resent SYN.
257 * sES -> sES :-)
258 * sFW -> sCW Normal close request answered by ACK.
259 * sCW -> sCW
260 * sLA -> sTW Last ACK detected.
261 * sTW -> sTW Retransmitted last ACK.
262 * sCL -> sCL
263 */
264 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
265 /*rst*/ { sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sIV },
266 /*none*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV }
267 }
268 };
269
270 static int tcp_pkt_to_tuple(const struct sk_buff *skb,
271 unsigned int dataoff,
272 struct nf_conntrack_tuple *tuple)
273 {
274 struct tcphdr _hdr, *hp;
275
276 /* Actually only need first 8 bytes. */
277 hp = skb_header_pointer(skb, dataoff, 8, &_hdr);
278 if (hp == NULL)
279 return 0;
280
281 tuple->src.u.tcp.port = hp->source;
282 tuple->dst.u.tcp.port = hp->dest;
283
284 return 1;
285 }
286
287 static int tcp_invert_tuple(struct nf_conntrack_tuple *tuple,
288 const struct nf_conntrack_tuple *orig)
289 {
290 tuple->src.u.tcp.port = orig->dst.u.tcp.port;
291 tuple->dst.u.tcp.port = orig->src.u.tcp.port;
292 return 1;
293 }
294
295 /* Print out the per-protocol part of the tuple. */
296 static int tcp_print_tuple(struct seq_file *s,
297 const struct nf_conntrack_tuple *tuple)
298 {
299 return seq_printf(s, "sport=%hu dport=%hu ",
300 ntohs(tuple->src.u.tcp.port),
301 ntohs(tuple->dst.u.tcp.port));
302 }
303
304 /* Print out the private part of the conntrack. */
305 static int tcp_print_conntrack(struct seq_file *s,
306 const struct nf_conn *conntrack)
307 {
308 enum tcp_conntrack state;
309
310 read_lock_bh(&tcp_lock);
311 state = conntrack->proto.tcp.state;
312 read_unlock_bh(&tcp_lock);
313
314 return seq_printf(s, "%s ", tcp_conntrack_names[state]);
315 }
316
317 static unsigned int get_conntrack_index(const struct tcphdr *tcph)
318 {
319 if (tcph->rst) return TCP_RST_SET;
320 else if (tcph->syn) return (tcph->ack ? TCP_SYNACK_SET : TCP_SYN_SET);
321 else if (tcph->fin) return TCP_FIN_SET;
322 else if (tcph->ack) return TCP_ACK_SET;
323 else return TCP_NONE_SET;
324 }
325
326 /* TCP connection tracking based on 'Real Stateful TCP Packet Filtering
327 in IP Filter' by Guido van Rooij.
328
329 http://www.nluug.nl/events/sane2000/papers.html
330 http://www.iae.nl/users/guido/papers/tcp_filtering.ps.gz
331
332 The boundaries and the conditions are changed according to RFC793:
333 the packet must intersect the window (i.e. segments may be
334 after the right or before the left edge) and thus receivers may ACK
335 segments after the right edge of the window.
336
337 td_maxend = max(sack + max(win,1)) seen in reply packets
338 td_maxwin = max(max(win, 1)) + (sack - ack) seen in sent packets
339 td_maxwin += seq + len - sender.td_maxend
340 if seq + len > sender.td_maxend
341 td_end = max(seq + len) seen in sent packets
342
343 I. Upper bound for valid data: seq <= sender.td_maxend
344 II. Lower bound for valid data: seq + len >= sender.td_end - receiver.td_maxwin
345 III. Upper bound for valid ack: sack <= receiver.td_end
346 IV. Lower bound for valid ack: ack >= receiver.td_end - MAXACKWINDOW
347
348 where sack is the highest right edge of sack block found in the packet.
349
350 The upper bound limit for a valid ack is not ignored -
351 we doesn't have to deal with fragments.
352 */
353
354 static inline __u32 segment_seq_plus_len(__u32 seq,
355 size_t len,
356 unsigned int dataoff,
357 struct tcphdr *tcph)
358 {
359 /* XXX Should I use payload length field in IP/IPv6 header ?
360 * - YK */
361 return (seq + len - dataoff - tcph->doff*4
362 + (tcph->syn ? 1 : 0) + (tcph->fin ? 1 : 0));
363 }
364
365 /* Fixme: what about big packets? */
366 #define MAXACKWINCONST 66000
367 #define MAXACKWINDOW(sender) \
368 ((sender)->td_maxwin > MAXACKWINCONST ? (sender)->td_maxwin \
369 : MAXACKWINCONST)
370
371 /*
372 * Simplified tcp_parse_options routine from tcp_input.c
373 */
374 static void tcp_options(const struct sk_buff *skb,
375 unsigned int dataoff,
376 struct tcphdr *tcph,
377 struct ip_ct_tcp_state *state)
378 {
379 unsigned char buff[(15 * 4) - sizeof(struct tcphdr)];
380 unsigned char *ptr;
381 int length = (tcph->doff*4) - sizeof(struct tcphdr);
382
383 if (!length)
384 return;
385
386 ptr = skb_header_pointer(skb, dataoff + sizeof(struct tcphdr),
387 length, buff);
388 BUG_ON(ptr == NULL);
389
390 state->td_scale =
391 state->flags = 0;
392
393 while (length > 0) {
394 int opcode=*ptr++;
395 int opsize;
396
397 switch (opcode) {
398 case TCPOPT_EOL:
399 return;
400 case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */
401 length--;
402 continue;
403 default:
404 opsize=*ptr++;
405 if (opsize < 2) /* "silly options" */
406 return;
407 if (opsize > length)
408 break; /* don't parse partial options */
409
410 if (opcode == TCPOPT_SACK_PERM
411 && opsize == TCPOLEN_SACK_PERM)
412 state->flags |= IP_CT_TCP_FLAG_SACK_PERM;
413 else if (opcode == TCPOPT_WINDOW
414 && opsize == TCPOLEN_WINDOW) {
415 state->td_scale = *(u_int8_t *)ptr;
416
417 if (state->td_scale > 14) {
418 /* See RFC1323 */
419 state->td_scale = 14;
420 }
421 state->flags |=
422 IP_CT_TCP_FLAG_WINDOW_SCALE;
423 }
424 ptr += opsize - 2;
425 length -= opsize;
426 }
427 }
428 }
429
430 static void tcp_sack(const struct sk_buff *skb, unsigned int dataoff,
431 struct tcphdr *tcph, __u32 *sack)
432 {
433 unsigned char buff[(15 * 4) - sizeof(struct tcphdr)];
434 unsigned char *ptr;
435 int length = (tcph->doff*4) - sizeof(struct tcphdr);
436 __u32 tmp;
437
438 if (!length)
439 return;
440
441 ptr = skb_header_pointer(skb, dataoff + sizeof(struct tcphdr),
442 length, buff);
443 BUG_ON(ptr == NULL);
444
445 /* Fast path for timestamp-only option */
446 if (length == TCPOLEN_TSTAMP_ALIGNED*4
447 && *(__be32 *)ptr == htonl((TCPOPT_NOP << 24)
448 | (TCPOPT_NOP << 16)
449 | (TCPOPT_TIMESTAMP << 8)
450 | TCPOLEN_TIMESTAMP))
451 return;
452
453 while (length > 0) {
454 int opcode = *ptr++;
455 int opsize, i;
456
457 switch (opcode) {
458 case TCPOPT_EOL:
459 return;
460 case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */
461 length--;
462 continue;
463 default:
464 opsize = *ptr++;
465 if (opsize < 2) /* "silly options" */
466 return;
467 if (opsize > length)
468 break; /* don't parse partial options */
469
470 if (opcode == TCPOPT_SACK
471 && opsize >= (TCPOLEN_SACK_BASE
472 + TCPOLEN_SACK_PERBLOCK)
473 && !((opsize - TCPOLEN_SACK_BASE)
474 % TCPOLEN_SACK_PERBLOCK)) {
475 for (i = 0;
476 i < (opsize - TCPOLEN_SACK_BASE);
477 i += TCPOLEN_SACK_PERBLOCK) {
478 tmp = ntohl(*((__be32 *)(ptr+i)+1));
479
480 if (after(tmp, *sack))
481 *sack = tmp;
482 }
483 return;
484 }
485 ptr += opsize - 2;
486 length -= opsize;
487 }
488 }
489 }
490
491 static int tcp_in_window(struct nf_conn *ct,
492 struct ip_ct_tcp *state,
493 enum ip_conntrack_dir dir,
494 unsigned int index,
495 const struct sk_buff *skb,
496 unsigned int dataoff,
497 struct tcphdr *tcph,
498 int pf)
499 {
500 struct ip_ct_tcp_state *sender = &state->seen[dir];
501 struct ip_ct_tcp_state *receiver = &state->seen[!dir];
502 struct nf_conntrack_tuple *tuple = &ct->tuplehash[dir].tuple;
503 __u32 seq, ack, sack, end, win, swin;
504 int res;
505
506 /*
507 * Get the required data from the packet.
508 */
509 seq = ntohl(tcph->seq);
510 ack = sack = ntohl(tcph->ack_seq);
511 win = ntohs(tcph->window);
512 end = segment_seq_plus_len(seq, skb->len, dataoff, tcph);
513
514 if (receiver->flags & IP_CT_TCP_FLAG_SACK_PERM)
515 tcp_sack(skb, dataoff, tcph, &sack);
516
517 pr_debug("tcp_in_window: START\n");
518 pr_debug("tcp_in_window: ");
519 NF_CT_DUMP_TUPLE(tuple);
520 pr_debug("seq=%u ack=%u sack=%u win=%u end=%u\n",
521 seq, ack, sack, win, end);
522 pr_debug("tcp_in_window: sender end=%u maxend=%u maxwin=%u scale=%i "
523 "receiver end=%u maxend=%u maxwin=%u scale=%i\n",
524 sender->td_end, sender->td_maxend, sender->td_maxwin,
525 sender->td_scale,
526 receiver->td_end, receiver->td_maxend, receiver->td_maxwin,
527 receiver->td_scale);
528
529 if (sender->td_end == 0) {
530 /*
531 * Initialize sender data.
532 */
533 if (tcph->syn && tcph->ack) {
534 /*
535 * Outgoing SYN-ACK in reply to a SYN.
536 */
537 sender->td_end =
538 sender->td_maxend = end;
539 sender->td_maxwin = (win == 0 ? 1 : win);
540
541 tcp_options(skb, dataoff, tcph, sender);
542 /*
543 * RFC 1323:
544 * Both sides must send the Window Scale option
545 * to enable window scaling in either direction.
546 */
547 if (!(sender->flags & IP_CT_TCP_FLAG_WINDOW_SCALE
548 && receiver->flags & IP_CT_TCP_FLAG_WINDOW_SCALE))
549 sender->td_scale =
550 receiver->td_scale = 0;
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 sender->td_maxwin = (win == 0 ? 1 : win);
559 sender->td_maxend = end + sender->td_maxwin;
560 }
561 } else if (((state->state == TCP_CONNTRACK_SYN_SENT
562 && dir == IP_CT_DIR_ORIGINAL)
563 || (state->state == TCP_CONNTRACK_SYN_RECV
564 && dir == IP_CT_DIR_REPLY))
565 && after(end, sender->td_end)) {
566 /*
567 * RFC 793: "if a TCP is reinitialized ... then it need
568 * not wait at all; it must only be sure to use sequence
569 * numbers larger than those recently used."
570 */
571 sender->td_end =
572 sender->td_maxend = end;
573 sender->td_maxwin = (win == 0 ? 1 : win);
574
575 tcp_options(skb, dataoff, tcph, sender);
576 }
577
578 if (!(tcph->ack)) {
579 /*
580 * If there is no ACK, just pretend it was set and OK.
581 */
582 ack = sack = receiver->td_end;
583 } else if (((tcp_flag_word(tcph) & (TCP_FLAG_ACK|TCP_FLAG_RST)) ==
584 (TCP_FLAG_ACK|TCP_FLAG_RST))
585 && (ack == 0)) {
586 /*
587 * Broken TCP stacks, that set ACK in RST packets as well
588 * with zero ack value.
589 */
590 ack = sack = receiver->td_end;
591 }
592
593 if (seq == end
594 && (!tcph->rst
595 || (seq == 0 && state->state == TCP_CONNTRACK_SYN_SENT)))
596 /*
597 * Packets contains no data: we assume it is valid
598 * and check the ack value only.
599 * However RST segments are always validated by their
600 * SEQ number, except when seq == 0 (reset sent answering
601 * SYN.
602 */
603 seq = end = sender->td_end;
604
605 pr_debug("tcp_in_window: ");
606 NF_CT_DUMP_TUPLE(tuple);
607 pr_debug("seq=%u ack=%u sack =%u win=%u end=%u\n",
608 seq, ack, sack, win, end);
609 pr_debug("tcp_in_window: sender end=%u maxend=%u maxwin=%u scale=%i "
610 "receiver end=%u maxend=%u maxwin=%u scale=%i\n",
611 sender->td_end, sender->td_maxend, sender->td_maxwin,
612 sender->td_scale,
613 receiver->td_end, receiver->td_maxend, receiver->td_maxwin,
614 receiver->td_scale);
615
616 pr_debug("tcp_in_window: I=%i II=%i III=%i IV=%i\n",
617 before(seq, sender->td_maxend + 1),
618 after(end, sender->td_end - receiver->td_maxwin - 1),
619 before(sack, receiver->td_end + 1),
620 after(ack, receiver->td_end - MAXACKWINDOW(sender)));
621
622 if (before(seq, sender->td_maxend + 1) &&
623 after(end, sender->td_end - receiver->td_maxwin - 1) &&
624 before(sack, receiver->td_end + 1) &&
625 after(ack, receiver->td_end - MAXACKWINDOW(sender))) {
626 /*
627 * Take into account window scaling (RFC 1323).
628 */
629 if (!tcph->syn)
630 win <<= sender->td_scale;
631
632 /*
633 * Update sender data.
634 */
635 swin = win + (sack - ack);
636 if (sender->td_maxwin < swin)
637 sender->td_maxwin = swin;
638 if (after(end, sender->td_end))
639 sender->td_end = end;
640 /*
641 * Update receiver data.
642 */
643 if (after(end, sender->td_maxend))
644 receiver->td_maxwin += end - sender->td_maxend;
645 if (after(sack + win, receiver->td_maxend - 1)) {
646 receiver->td_maxend = sack + win;
647 if (win == 0)
648 receiver->td_maxend++;
649 }
650
651 /*
652 * Check retransmissions.
653 */
654 if (index == TCP_ACK_SET) {
655 if (state->last_dir == dir
656 && state->last_seq == seq
657 && state->last_ack == ack
658 && state->last_end == end
659 && state->last_win == win)
660 state->retrans++;
661 else {
662 state->last_dir = dir;
663 state->last_seq = seq;
664 state->last_ack = ack;
665 state->last_end = end;
666 state->last_win = win;
667 state->retrans = 0;
668 }
669 }
670 res = 1;
671 } else {
672 res = 0;
673 if (sender->flags & IP_CT_TCP_FLAG_BE_LIBERAL ||
674 nf_ct_tcp_be_liberal)
675 res = 1;
676 if (!res && LOG_INVALID(IPPROTO_TCP))
677 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
678 "nf_ct_tcp: %s ",
679 before(seq, sender->td_maxend + 1) ?
680 after(end, sender->td_end - receiver->td_maxwin - 1) ?
681 before(sack, receiver->td_end + 1) ?
682 after(ack, receiver->td_end - MAXACKWINDOW(sender)) ? "BUG"
683 : "ACK is under the lower bound (possible overly delayed ACK)"
684 : "ACK is over the upper bound (ACKed data not seen yet)"
685 : "SEQ is under the lower bound (already ACKed data retransmitted)"
686 : "SEQ is over the upper bound (over the window of the receiver)");
687 }
688
689 pr_debug("tcp_in_window: res=%i sender end=%u maxend=%u maxwin=%u "
690 "receiver end=%u maxend=%u maxwin=%u\n",
691 res, sender->td_end, sender->td_maxend, sender->td_maxwin,
692 receiver->td_end, receiver->td_maxend, receiver->td_maxwin);
693
694 return res;
695 }
696
697 #ifdef CONFIG_NF_NAT_NEEDED
698 /* Update sender->td_end after NAT successfully mangled the packet */
699 /* Caller must linearize skb at tcp header. */
700 void nf_conntrack_tcp_update(struct sk_buff *skb,
701 unsigned int dataoff,
702 struct nf_conn *conntrack,
703 int dir)
704 {
705 struct tcphdr *tcph = (void *)skb->data + dataoff;
706 struct ip_ct_tcp_state *sender = &conntrack->proto.tcp.seen[dir];
707 struct ip_ct_tcp_state *receiver = &conntrack->proto.tcp.seen[!dir];
708 __u32 end;
709
710 end = segment_seq_plus_len(ntohl(tcph->seq), skb->len, dataoff, tcph);
711
712 write_lock_bh(&tcp_lock);
713 /*
714 * We have to worry for the ack in the reply packet only...
715 */
716 if (after(end, conntrack->proto.tcp.seen[dir].td_end))
717 conntrack->proto.tcp.seen[dir].td_end = end;
718 conntrack->proto.tcp.last_end = end;
719 write_unlock_bh(&tcp_lock);
720 pr_debug("tcp_update: sender end=%u maxend=%u maxwin=%u scale=%i "
721 "receiver end=%u maxend=%u maxwin=%u scale=%i\n",
722 sender->td_end, sender->td_maxend, sender->td_maxwin,
723 sender->td_scale,
724 receiver->td_end, receiver->td_maxend, receiver->td_maxwin,
725 receiver->td_scale);
726 }
727 EXPORT_SYMBOL_GPL(nf_conntrack_tcp_update);
728 #endif
729
730 #define TH_FIN 0x01
731 #define TH_SYN 0x02
732 #define TH_RST 0x04
733 #define TH_PUSH 0x08
734 #define TH_ACK 0x10
735 #define TH_URG 0x20
736 #define TH_ECE 0x40
737 #define TH_CWR 0x80
738
739 /* table of valid flag combinations - PUSH, ECE and CWR are always valid */
740 static u8 tcp_valid_flags[(TH_FIN|TH_SYN|TH_RST|TH_ACK|TH_URG) + 1] =
741 {
742 [TH_SYN] = 1,
743 [TH_SYN|TH_URG] = 1,
744 [TH_SYN|TH_ACK] = 1,
745 [TH_RST] = 1,
746 [TH_RST|TH_ACK] = 1,
747 [TH_FIN|TH_ACK] = 1,
748 [TH_FIN|TH_ACK|TH_URG] = 1,
749 [TH_ACK] = 1,
750 [TH_ACK|TH_URG] = 1,
751 };
752
753 /* Protect conntrack agaist broken packets. Code taken from ipt_unclean.c. */
754 static int tcp_error(struct sk_buff *skb,
755 unsigned int dataoff,
756 enum ip_conntrack_info *ctinfo,
757 int pf,
758 unsigned int hooknum)
759 {
760 struct tcphdr _tcph, *th;
761 unsigned int tcplen = skb->len - dataoff;
762 u_int8_t tcpflags;
763
764 /* Smaller that minimal TCP header? */
765 th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph);
766 if (th == NULL) {
767 if (LOG_INVALID(IPPROTO_TCP))
768 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
769 "nf_ct_tcp: short packet ");
770 return -NF_ACCEPT;
771 }
772
773 /* Not whole TCP header or malformed packet */
774 if (th->doff*4 < sizeof(struct tcphdr) || tcplen < th->doff*4) {
775 if (LOG_INVALID(IPPROTO_TCP))
776 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
777 "nf_ct_tcp: truncated/malformed packet ");
778 return -NF_ACCEPT;
779 }
780
781 /* Checksum invalid? Ignore.
782 * We skip checking packets on the outgoing path
783 * because the checksum is assumed to be correct.
784 */
785 /* FIXME: Source route IP option packets --RR */
786 if (nf_conntrack_checksum && hooknum == NF_INET_PRE_ROUTING &&
787 nf_checksum(skb, hooknum, dataoff, IPPROTO_TCP, pf)) {
788 if (LOG_INVALID(IPPROTO_TCP))
789 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
790 "nf_ct_tcp: bad TCP checksum ");
791 return -NF_ACCEPT;
792 }
793
794 /* Check TCP flags. */
795 tcpflags = (((u_int8_t *)th)[13] & ~(TH_ECE|TH_CWR|TH_PUSH));
796 if (!tcp_valid_flags[tcpflags]) {
797 if (LOG_INVALID(IPPROTO_TCP))
798 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
799 "nf_ct_tcp: invalid TCP flag combination ");
800 return -NF_ACCEPT;
801 }
802
803 return NF_ACCEPT;
804 }
805
806 /* Returns verdict for packet, or -1 for invalid. */
807 static int tcp_packet(struct nf_conn *conntrack,
808 const struct sk_buff *skb,
809 unsigned int dataoff,
810 enum ip_conntrack_info ctinfo,
811 int pf,
812 unsigned int hooknum)
813 {
814 struct nf_conntrack_tuple *tuple;
815 enum tcp_conntrack new_state, old_state;
816 enum ip_conntrack_dir dir;
817 struct tcphdr *th, _tcph;
818 unsigned long timeout;
819 unsigned int index;
820
821 th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph);
822 BUG_ON(th == NULL);
823
824 write_lock_bh(&tcp_lock);
825 old_state = conntrack->proto.tcp.state;
826 dir = CTINFO2DIR(ctinfo);
827 index = get_conntrack_index(th);
828 new_state = tcp_conntracks[dir][index][old_state];
829 tuple = &conntrack->tuplehash[dir].tuple;
830
831 switch (new_state) {
832 case TCP_CONNTRACK_SYN_SENT:
833 if (old_state < TCP_CONNTRACK_TIME_WAIT)
834 break;
835 if ((conntrack->proto.tcp.seen[!dir].flags &
836 IP_CT_TCP_FLAG_CLOSE_INIT)
837 || (conntrack->proto.tcp.last_dir == dir
838 && conntrack->proto.tcp.last_index == TCP_RST_SET)) {
839 /* Attempt to reopen a closed/aborted connection.
840 * Delete this connection and look up again. */
841 write_unlock_bh(&tcp_lock);
842 if (del_timer(&conntrack->timeout))
843 conntrack->timeout.function((unsigned long)
844 conntrack);
845 return -NF_REPEAT;
846 }
847 /* Fall through */
848 case TCP_CONNTRACK_IGNORE:
849 /* Ignored packets:
850 *
851 * a) SYN in ORIGINAL
852 * b) SYN/ACK in REPLY
853 * c) ACK in reply direction after initial SYN in original.
854 */
855 if (index == TCP_SYNACK_SET
856 && conntrack->proto.tcp.last_index == TCP_SYN_SET
857 && conntrack->proto.tcp.last_dir != dir
858 && ntohl(th->ack_seq) ==
859 conntrack->proto.tcp.last_end) {
860 /* This SYN/ACK acknowledges a SYN that we earlier
861 * ignored as invalid. This means that the client and
862 * the server are both in sync, while the firewall is
863 * not. We kill this session and block the SYN/ACK so
864 * that the client cannot but retransmit its SYN and
865 * thus initiate a clean new session.
866 */
867 write_unlock_bh(&tcp_lock);
868 if (LOG_INVALID(IPPROTO_TCP))
869 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
870 "nf_ct_tcp: killing out of sync session ");
871 if (del_timer(&conntrack->timeout))
872 conntrack->timeout.function((unsigned long)
873 conntrack);
874 return -NF_DROP;
875 }
876 conntrack->proto.tcp.last_index = index;
877 conntrack->proto.tcp.last_dir = dir;
878 conntrack->proto.tcp.last_seq = ntohl(th->seq);
879 conntrack->proto.tcp.last_end =
880 segment_seq_plus_len(ntohl(th->seq), skb->len, dataoff, th);
881
882 write_unlock_bh(&tcp_lock);
883 if (LOG_INVALID(IPPROTO_TCP))
884 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
885 "nf_ct_tcp: invalid packed ignored ");
886 return NF_ACCEPT;
887 case TCP_CONNTRACK_MAX:
888 /* Invalid packet */
889 pr_debug("nf_ct_tcp: Invalid dir=%i index=%u ostate=%u\n",
890 dir, get_conntrack_index(th), old_state);
891 write_unlock_bh(&tcp_lock);
892 if (LOG_INVALID(IPPROTO_TCP))
893 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
894 "nf_ct_tcp: invalid state ");
895 return -NF_ACCEPT;
896 case TCP_CONNTRACK_CLOSE:
897 if (index == TCP_RST_SET
898 && ((test_bit(IPS_SEEN_REPLY_BIT, &conntrack->status)
899 && conntrack->proto.tcp.last_index == TCP_SYN_SET)
900 || (!test_bit(IPS_ASSURED_BIT, &conntrack->status)
901 && conntrack->proto.tcp.last_index == TCP_ACK_SET))
902 && ntohl(th->ack_seq) == conntrack->proto.tcp.last_end) {
903 /* RST sent to invalid SYN or ACK we had let through
904 * at a) and c) above:
905 *
906 * a) SYN was in window then
907 * c) we hold a half-open connection.
908 *
909 * Delete our connection entry.
910 * We skip window checking, because packet might ACK
911 * segments we ignored. */
912 goto in_window;
913 }
914 /* Just fall through */
915 default:
916 /* Keep compilers happy. */
917 break;
918 }
919
920 if (!tcp_in_window(conntrack, &conntrack->proto.tcp, dir, index,
921 skb, dataoff, th, pf)) {
922 write_unlock_bh(&tcp_lock);
923 return -NF_ACCEPT;
924 }
925 in_window:
926 /* From now on we have got in-window packets */
927 conntrack->proto.tcp.last_index = index;
928 conntrack->proto.tcp.last_dir = dir;
929
930 pr_debug("tcp_conntracks: ");
931 NF_CT_DUMP_TUPLE(tuple);
932 pr_debug("syn=%i ack=%i fin=%i rst=%i old=%i new=%i\n",
933 (th->syn ? 1 : 0), (th->ack ? 1 : 0),
934 (th->fin ? 1 : 0), (th->rst ? 1 : 0),
935 old_state, new_state);
936
937 conntrack->proto.tcp.state = new_state;
938 if (old_state != new_state
939 && (new_state == TCP_CONNTRACK_FIN_WAIT
940 || new_state == TCP_CONNTRACK_CLOSE))
941 conntrack->proto.tcp.seen[dir].flags |= IP_CT_TCP_FLAG_CLOSE_INIT;
942 timeout = conntrack->proto.tcp.retrans >= nf_ct_tcp_max_retrans
943 && *tcp_timeouts[new_state] > nf_ct_tcp_timeout_max_retrans
944 ? nf_ct_tcp_timeout_max_retrans : *tcp_timeouts[new_state];
945 write_unlock_bh(&tcp_lock);
946
947 nf_conntrack_event_cache(IPCT_PROTOINFO_VOLATILE, skb);
948 if (new_state != old_state)
949 nf_conntrack_event_cache(IPCT_PROTOINFO, skb);
950
951 if (!test_bit(IPS_SEEN_REPLY_BIT, &conntrack->status)) {
952 /* If only reply is a RST, we can consider ourselves not to
953 have an established connection: this is a fairly common
954 problem case, so we can delete the conntrack
955 immediately. --RR */
956 if (th->rst) {
957 if (del_timer(&conntrack->timeout))
958 conntrack->timeout.function((unsigned long)
959 conntrack);
960 return NF_ACCEPT;
961 }
962 } else if (!test_bit(IPS_ASSURED_BIT, &conntrack->status)
963 && (old_state == TCP_CONNTRACK_SYN_RECV
964 || old_state == TCP_CONNTRACK_ESTABLISHED)
965 && new_state == TCP_CONNTRACK_ESTABLISHED) {
966 /* Set ASSURED if we see see valid ack in ESTABLISHED
967 after SYN_RECV or a valid answer for a picked up
968 connection. */
969 set_bit(IPS_ASSURED_BIT, &conntrack->status);
970 nf_conntrack_event_cache(IPCT_STATUS, skb);
971 }
972 nf_ct_refresh_acct(conntrack, ctinfo, skb, timeout);
973
974 return NF_ACCEPT;
975 }
976
977 /* Called when a new connection for this protocol found. */
978 static int tcp_new(struct nf_conn *conntrack,
979 const struct sk_buff *skb,
980 unsigned int dataoff)
981 {
982 enum tcp_conntrack new_state;
983 struct tcphdr *th, _tcph;
984 struct ip_ct_tcp_state *sender = &conntrack->proto.tcp.seen[0];
985 struct ip_ct_tcp_state *receiver = &conntrack->proto.tcp.seen[1];
986
987 th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph);
988 BUG_ON(th == NULL);
989
990 /* Don't need lock here: this conntrack not in circulation yet */
991 new_state
992 = tcp_conntracks[0][get_conntrack_index(th)]
993 [TCP_CONNTRACK_NONE];
994
995 /* Invalid: delete conntrack */
996 if (new_state >= TCP_CONNTRACK_MAX) {
997 pr_debug("nf_ct_tcp: invalid new deleting.\n");
998 return 0;
999 }
1000
1001 if (new_state == TCP_CONNTRACK_SYN_SENT) {
1002 /* SYN packet */
1003 conntrack->proto.tcp.seen[0].td_end =
1004 segment_seq_plus_len(ntohl(th->seq), skb->len,
1005 dataoff, th);
1006 conntrack->proto.tcp.seen[0].td_maxwin = ntohs(th->window);
1007 if (conntrack->proto.tcp.seen[0].td_maxwin == 0)
1008 conntrack->proto.tcp.seen[0].td_maxwin = 1;
1009 conntrack->proto.tcp.seen[0].td_maxend =
1010 conntrack->proto.tcp.seen[0].td_end;
1011
1012 tcp_options(skb, dataoff, th, &conntrack->proto.tcp.seen[0]);
1013 conntrack->proto.tcp.seen[1].flags = 0;
1014 } else if (nf_ct_tcp_loose == 0) {
1015 /* Don't try to pick up connections. */
1016 return 0;
1017 } else {
1018 /*
1019 * We are in the middle of a connection,
1020 * its history is lost for us.
1021 * Let's try to use the data from the packet.
1022 */
1023 conntrack->proto.tcp.seen[0].td_end =
1024 segment_seq_plus_len(ntohl(th->seq), skb->len,
1025 dataoff, th);
1026 conntrack->proto.tcp.seen[0].td_maxwin = ntohs(th->window);
1027 if (conntrack->proto.tcp.seen[0].td_maxwin == 0)
1028 conntrack->proto.tcp.seen[0].td_maxwin = 1;
1029 conntrack->proto.tcp.seen[0].td_maxend =
1030 conntrack->proto.tcp.seen[0].td_end +
1031 conntrack->proto.tcp.seen[0].td_maxwin;
1032 conntrack->proto.tcp.seen[0].td_scale = 0;
1033
1034 /* We assume SACK and liberal window checking to handle
1035 * window scaling */
1036 conntrack->proto.tcp.seen[0].flags =
1037 conntrack->proto.tcp.seen[1].flags = IP_CT_TCP_FLAG_SACK_PERM |
1038 IP_CT_TCP_FLAG_BE_LIBERAL;
1039 }
1040
1041 conntrack->proto.tcp.seen[1].td_end = 0;
1042 conntrack->proto.tcp.seen[1].td_maxend = 0;
1043 conntrack->proto.tcp.seen[1].td_maxwin = 1;
1044 conntrack->proto.tcp.seen[1].td_scale = 0;
1045
1046 /* tcp_packet will set them */
1047 conntrack->proto.tcp.state = TCP_CONNTRACK_NONE;
1048 conntrack->proto.tcp.last_index = TCP_NONE_SET;
1049
1050 pr_debug("tcp_new: sender end=%u maxend=%u maxwin=%u scale=%i "
1051 "receiver end=%u maxend=%u maxwin=%u scale=%i\n",
1052 sender->td_end, sender->td_maxend, sender->td_maxwin,
1053 sender->td_scale,
1054 receiver->td_end, receiver->td_maxend, receiver->td_maxwin,
1055 receiver->td_scale);
1056 return 1;
1057 }
1058
1059 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
1060
1061 #include <linux/netfilter/nfnetlink.h>
1062 #include <linux/netfilter/nfnetlink_conntrack.h>
1063
1064 static int tcp_to_nlattr(struct sk_buff *skb, struct nlattr *nla,
1065 const struct nf_conn *ct)
1066 {
1067 struct nlattr *nest_parms;
1068 struct nf_ct_tcp_flags tmp = {};
1069
1070 read_lock_bh(&tcp_lock);
1071 nest_parms = nla_nest_start(skb, CTA_PROTOINFO_TCP | NLA_F_NESTED);
1072 if (!nest_parms)
1073 goto nla_put_failure;
1074
1075 NLA_PUT_U8(skb, CTA_PROTOINFO_TCP_STATE, ct->proto.tcp.state);
1076
1077 NLA_PUT_U8(skb, CTA_PROTOINFO_TCP_WSCALE_ORIGINAL,
1078 ct->proto.tcp.seen[0].td_scale);
1079
1080 NLA_PUT_U8(skb, CTA_PROTOINFO_TCP_WSCALE_REPLY,
1081 ct->proto.tcp.seen[1].td_scale);
1082
1083 tmp.flags = ct->proto.tcp.seen[0].flags;
1084 NLA_PUT(skb, CTA_PROTOINFO_TCP_FLAGS_ORIGINAL,
1085 sizeof(struct nf_ct_tcp_flags), &tmp);
1086
1087 tmp.flags = ct->proto.tcp.seen[1].flags;
1088 NLA_PUT(skb, CTA_PROTOINFO_TCP_FLAGS_REPLY,
1089 sizeof(struct nf_ct_tcp_flags), &tmp);
1090 read_unlock_bh(&tcp_lock);
1091
1092 nla_nest_end(skb, nest_parms);
1093
1094 return 0;
1095
1096 nla_put_failure:
1097 read_unlock_bh(&tcp_lock);
1098 return -1;
1099 }
1100
1101 static const struct nla_policy tcp_nla_policy[CTA_PROTOINFO_TCP_MAX+1] = {
1102 [CTA_PROTOINFO_TCP_STATE] = { .type = NLA_U8 },
1103 [CTA_PROTOINFO_TCP_WSCALE_ORIGINAL] = { .type = NLA_U8 },
1104 [CTA_PROTOINFO_TCP_WSCALE_REPLY] = { .type = NLA_U8 },
1105 [CTA_PROTOINFO_TCP_FLAGS_ORIGINAL] = { .len = sizeof(struct nf_ct_tcp_flags) },
1106 [CTA_PROTOINFO_TCP_FLAGS_REPLY] = { .len = sizeof(struct nf_ct_tcp_flags) },
1107 };
1108
1109 static int nlattr_to_tcp(struct nlattr *cda[], struct nf_conn *ct)
1110 {
1111 struct nlattr *attr = cda[CTA_PROTOINFO_TCP];
1112 struct nlattr *tb[CTA_PROTOINFO_TCP_MAX+1];
1113 int err;
1114
1115 /* updates could not contain anything about the private
1116 * protocol info, in that case skip the parsing */
1117 if (!attr)
1118 return 0;
1119
1120 err = nla_parse_nested(tb, CTA_PROTOINFO_TCP_MAX, attr, tcp_nla_policy);
1121 if (err < 0)
1122 return err;
1123
1124 if (!tb[CTA_PROTOINFO_TCP_STATE])
1125 return -EINVAL;
1126
1127 write_lock_bh(&tcp_lock);
1128 ct->proto.tcp.state = nla_get_u8(tb[CTA_PROTOINFO_TCP_STATE]);
1129
1130 if (tb[CTA_PROTOINFO_TCP_FLAGS_ORIGINAL]) {
1131 struct nf_ct_tcp_flags *attr =
1132 nla_data(tb[CTA_PROTOINFO_TCP_FLAGS_ORIGINAL]);
1133 ct->proto.tcp.seen[0].flags &= ~attr->mask;
1134 ct->proto.tcp.seen[0].flags |= attr->flags & attr->mask;
1135 }
1136
1137 if (tb[CTA_PROTOINFO_TCP_FLAGS_REPLY]) {
1138 struct nf_ct_tcp_flags *attr =
1139 nla_data(tb[CTA_PROTOINFO_TCP_FLAGS_REPLY]);
1140 ct->proto.tcp.seen[1].flags &= ~attr->mask;
1141 ct->proto.tcp.seen[1].flags |= attr->flags & attr->mask;
1142 }
1143
1144 if (tb[CTA_PROTOINFO_TCP_WSCALE_ORIGINAL] &&
1145 tb[CTA_PROTOINFO_TCP_WSCALE_REPLY] &&
1146 ct->proto.tcp.seen[0].flags & IP_CT_TCP_FLAG_WINDOW_SCALE &&
1147 ct->proto.tcp.seen[1].flags & IP_CT_TCP_FLAG_WINDOW_SCALE) {
1148 ct->proto.tcp.seen[0].td_scale =
1149 nla_get_u8(tb[CTA_PROTOINFO_TCP_WSCALE_ORIGINAL]);
1150 ct->proto.tcp.seen[1].td_scale =
1151 nla_get_u8(tb[CTA_PROTOINFO_TCP_WSCALE_REPLY]);
1152 }
1153 write_unlock_bh(&tcp_lock);
1154
1155 return 0;
1156 }
1157 #endif
1158
1159 #ifdef CONFIG_SYSCTL
1160 static unsigned int tcp_sysctl_table_users;
1161 static struct ctl_table_header *tcp_sysctl_header;
1162 static struct ctl_table tcp_sysctl_table[] = {
1163 {
1164 .procname = "nf_conntrack_tcp_timeout_syn_sent",
1165 .data = &nf_ct_tcp_timeout_syn_sent,
1166 .maxlen = sizeof(unsigned int),
1167 .mode = 0644,
1168 .proc_handler = &proc_dointvec_jiffies,
1169 },
1170 {
1171 .procname = "nf_conntrack_tcp_timeout_syn_recv",
1172 .data = &nf_ct_tcp_timeout_syn_recv,
1173 .maxlen = sizeof(unsigned int),
1174 .mode = 0644,
1175 .proc_handler = &proc_dointvec_jiffies,
1176 },
1177 {
1178 .procname = "nf_conntrack_tcp_timeout_established",
1179 .data = &nf_ct_tcp_timeout_established,
1180 .maxlen = sizeof(unsigned int),
1181 .mode = 0644,
1182 .proc_handler = &proc_dointvec_jiffies,
1183 },
1184 {
1185 .procname = "nf_conntrack_tcp_timeout_fin_wait",
1186 .data = &nf_ct_tcp_timeout_fin_wait,
1187 .maxlen = sizeof(unsigned int),
1188 .mode = 0644,
1189 .proc_handler = &proc_dointvec_jiffies,
1190 },
1191 {
1192 .procname = "nf_conntrack_tcp_timeout_close_wait",
1193 .data = &nf_ct_tcp_timeout_close_wait,
1194 .maxlen = sizeof(unsigned int),
1195 .mode = 0644,
1196 .proc_handler = &proc_dointvec_jiffies,
1197 },
1198 {
1199 .procname = "nf_conntrack_tcp_timeout_last_ack",
1200 .data = &nf_ct_tcp_timeout_last_ack,
1201 .maxlen = sizeof(unsigned int),
1202 .mode = 0644,
1203 .proc_handler = &proc_dointvec_jiffies,
1204 },
1205 {
1206 .procname = "nf_conntrack_tcp_timeout_time_wait",
1207 .data = &nf_ct_tcp_timeout_time_wait,
1208 .maxlen = sizeof(unsigned int),
1209 .mode = 0644,
1210 .proc_handler = &proc_dointvec_jiffies,
1211 },
1212 {
1213 .procname = "nf_conntrack_tcp_timeout_close",
1214 .data = &nf_ct_tcp_timeout_close,
1215 .maxlen = sizeof(unsigned int),
1216 .mode = 0644,
1217 .proc_handler = &proc_dointvec_jiffies,
1218 },
1219 {
1220 .procname = "nf_conntrack_tcp_timeout_max_retrans",
1221 .data = &nf_ct_tcp_timeout_max_retrans,
1222 .maxlen = sizeof(unsigned int),
1223 .mode = 0644,
1224 .proc_handler = &proc_dointvec_jiffies,
1225 },
1226 {
1227 .ctl_name = NET_NF_CONNTRACK_TCP_LOOSE,
1228 .procname = "nf_conntrack_tcp_loose",
1229 .data = &nf_ct_tcp_loose,
1230 .maxlen = sizeof(unsigned int),
1231 .mode = 0644,
1232 .proc_handler = &proc_dointvec,
1233 },
1234 {
1235 .ctl_name = NET_NF_CONNTRACK_TCP_BE_LIBERAL,
1236 .procname = "nf_conntrack_tcp_be_liberal",
1237 .data = &nf_ct_tcp_be_liberal,
1238 .maxlen = sizeof(unsigned int),
1239 .mode = 0644,
1240 .proc_handler = &proc_dointvec,
1241 },
1242 {
1243 .ctl_name = NET_NF_CONNTRACK_TCP_MAX_RETRANS,
1244 .procname = "nf_conntrack_tcp_max_retrans",
1245 .data = &nf_ct_tcp_max_retrans,
1246 .maxlen = sizeof(unsigned int),
1247 .mode = 0644,
1248 .proc_handler = &proc_dointvec,
1249 },
1250 {
1251 .ctl_name = 0
1252 }
1253 };
1254
1255 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
1256 static struct ctl_table tcp_compat_sysctl_table[] = {
1257 {
1258 .procname = "ip_conntrack_tcp_timeout_syn_sent",
1259 .data = &nf_ct_tcp_timeout_syn_sent,
1260 .maxlen = sizeof(unsigned int),
1261 .mode = 0644,
1262 .proc_handler = &proc_dointvec_jiffies,
1263 },
1264 {
1265 .procname = "ip_conntrack_tcp_timeout_syn_recv",
1266 .data = &nf_ct_tcp_timeout_syn_recv,
1267 .maxlen = sizeof(unsigned int),
1268 .mode = 0644,
1269 .proc_handler = &proc_dointvec_jiffies,
1270 },
1271 {
1272 .procname = "ip_conntrack_tcp_timeout_established",
1273 .data = &nf_ct_tcp_timeout_established,
1274 .maxlen = sizeof(unsigned int),
1275 .mode = 0644,
1276 .proc_handler = &proc_dointvec_jiffies,
1277 },
1278 {
1279 .procname = "ip_conntrack_tcp_timeout_fin_wait",
1280 .data = &nf_ct_tcp_timeout_fin_wait,
1281 .maxlen = sizeof(unsigned int),
1282 .mode = 0644,
1283 .proc_handler = &proc_dointvec_jiffies,
1284 },
1285 {
1286 .procname = "ip_conntrack_tcp_timeout_close_wait",
1287 .data = &nf_ct_tcp_timeout_close_wait,
1288 .maxlen = sizeof(unsigned int),
1289 .mode = 0644,
1290 .proc_handler = &proc_dointvec_jiffies,
1291 },
1292 {
1293 .procname = "ip_conntrack_tcp_timeout_last_ack",
1294 .data = &nf_ct_tcp_timeout_last_ack,
1295 .maxlen = sizeof(unsigned int),
1296 .mode = 0644,
1297 .proc_handler = &proc_dointvec_jiffies,
1298 },
1299 {
1300 .procname = "ip_conntrack_tcp_timeout_time_wait",
1301 .data = &nf_ct_tcp_timeout_time_wait,
1302 .maxlen = sizeof(unsigned int),
1303 .mode = 0644,
1304 .proc_handler = &proc_dointvec_jiffies,
1305 },
1306 {
1307 .procname = "ip_conntrack_tcp_timeout_close",
1308 .data = &nf_ct_tcp_timeout_close,
1309 .maxlen = sizeof(unsigned int),
1310 .mode = 0644,
1311 .proc_handler = &proc_dointvec_jiffies,
1312 },
1313 {
1314 .procname = "ip_conntrack_tcp_timeout_max_retrans",
1315 .data = &nf_ct_tcp_timeout_max_retrans,
1316 .maxlen = sizeof(unsigned int),
1317 .mode = 0644,
1318 .proc_handler = &proc_dointvec_jiffies,
1319 },
1320 {
1321 .ctl_name = NET_IPV4_NF_CONNTRACK_TCP_LOOSE,
1322 .procname = "ip_conntrack_tcp_loose",
1323 .data = &nf_ct_tcp_loose,
1324 .maxlen = sizeof(unsigned int),
1325 .mode = 0644,
1326 .proc_handler = &proc_dointvec,
1327 },
1328 {
1329 .ctl_name = NET_IPV4_NF_CONNTRACK_TCP_BE_LIBERAL,
1330 .procname = "ip_conntrack_tcp_be_liberal",
1331 .data = &nf_ct_tcp_be_liberal,
1332 .maxlen = sizeof(unsigned int),
1333 .mode = 0644,
1334 .proc_handler = &proc_dointvec,
1335 },
1336 {
1337 .ctl_name = NET_IPV4_NF_CONNTRACK_TCP_MAX_RETRANS,
1338 .procname = "ip_conntrack_tcp_max_retrans",
1339 .data = &nf_ct_tcp_max_retrans,
1340 .maxlen = sizeof(unsigned int),
1341 .mode = 0644,
1342 .proc_handler = &proc_dointvec,
1343 },
1344 {
1345 .ctl_name = 0
1346 }
1347 };
1348 #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
1349 #endif /* CONFIG_SYSCTL */
1350
1351 struct nf_conntrack_l4proto nf_conntrack_l4proto_tcp4 __read_mostly =
1352 {
1353 .l3proto = PF_INET,
1354 .l4proto = IPPROTO_TCP,
1355 .name = "tcp",
1356 .pkt_to_tuple = tcp_pkt_to_tuple,
1357 .invert_tuple = tcp_invert_tuple,
1358 .print_tuple = tcp_print_tuple,
1359 .print_conntrack = tcp_print_conntrack,
1360 .packet = tcp_packet,
1361 .new = tcp_new,
1362 .error = tcp_error,
1363 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
1364 .to_nlattr = tcp_to_nlattr,
1365 .from_nlattr = nlattr_to_tcp,
1366 .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
1367 .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
1368 .nla_policy = nf_ct_port_nla_policy,
1369 #endif
1370 #ifdef CONFIG_SYSCTL
1371 .ctl_table_users = &tcp_sysctl_table_users,
1372 .ctl_table_header = &tcp_sysctl_header,
1373 .ctl_table = tcp_sysctl_table,
1374 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
1375 .ctl_compat_table = tcp_compat_sysctl_table,
1376 #endif
1377 #endif
1378 };
1379 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_tcp4);
1380
1381 struct nf_conntrack_l4proto nf_conntrack_l4proto_tcp6 __read_mostly =
1382 {
1383 .l3proto = PF_INET6,
1384 .l4proto = IPPROTO_TCP,
1385 .name = "tcp",
1386 .pkt_to_tuple = tcp_pkt_to_tuple,
1387 .invert_tuple = tcp_invert_tuple,
1388 .print_tuple = tcp_print_tuple,
1389 .print_conntrack = tcp_print_conntrack,
1390 .packet = tcp_packet,
1391 .new = tcp_new,
1392 .error = tcp_error,
1393 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
1394 .to_nlattr = tcp_to_nlattr,
1395 .from_nlattr = nlattr_to_tcp,
1396 .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
1397 .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
1398 .nla_policy = nf_ct_port_nla_policy,
1399 #endif
1400 #ifdef CONFIG_SYSCTL
1401 .ctl_table_users = &tcp_sysctl_table_users,
1402 .ctl_table_header = &tcp_sysctl_header,
1403 .ctl_table = tcp_sysctl_table,
1404 #endif
1405 };
1406 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_tcp6);
Linux kernel - Deliverables
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