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[NETFILTER]: Add address family specific checksum helpers
[linux-block.git] / net / netfilter / nf_conntrack_proto_tcp.c
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9fb9cbb1
YK		 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 */
56static 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. */
61int 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. */
68int 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. */
73int 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
78static 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
babbdb1a
PM		 96unsigned int nf_ct_tcp_timeout_syn_sent = 2 MINS;
97unsigned int nf_ct_tcp_timeout_syn_recv = 60 SECS;
98unsigned int nf_ct_tcp_timeout_established = 5 DAYS;
99unsigned int nf_ct_tcp_timeout_fin_wait = 2 MINS;
100unsigned int nf_ct_tcp_timeout_close_wait = 60 SECS;
101unsigned int nf_ct_tcp_timeout_last_ack = 30 SECS;
102unsigned int nf_ct_tcp_timeout_time_wait = 2 MINS;
103unsigned int nf_ct_tcp_timeout_close = 10 SECS;
9fb9cbb1
YK		 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. */
babbdb1a 108unsigned int nf_ct_tcp_timeout_max_retrans = 5 MINS;
9fb9cbb1 109
babbdb1a 110static unsigned int * tcp_timeouts[]
9fb9cbb1
YK		 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. */
137enum 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 */
181static 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 */
73f30602 283/*ack*/ { sIV, sIG, sSR, sES, sCW, sCW, sTW, sTW, sCL, sIV },
9fb9cbb1 284/*
73f30602 285 * sSS -> sIG Might be a half-open connection.
9fb9cbb1
YK		 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
300static 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
317static 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. */
326static 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. */
335static 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
347static 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
384static 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 */
404static 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
460static 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
524static 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. */
736void 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 */
778static 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,
a2d7222f 782 [TH_SYN|TH_PUSH] = 1,
9fb9cbb1
YK		 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. */
798static 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 int(*csum)(const struct sk_buff *,unsigned int))
804{
805 struct tcphdr _tcph, *th;
806 unsigned int tcplen = skb->len - dataoff;
807 u_int8_t tcpflags;
808
809 /* Smaller that minimal TCP header? */
810 th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph);
811 if (th == NULL) {
812 if (LOG_INVALID(IPPROTO_TCP))
813 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
814 "nf_ct_tcp: short packet ");
815 return -NF_ACCEPT;
816 }
817
818 /* Not whole TCP header or malformed packet */
819 if (th->doff*4 < sizeof(struct tcphdr) || tcplen < th->doff*4) {
820 if (LOG_INVALID(IPPROTO_TCP))
821 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
822 "nf_ct_tcp: truncated/malformed packet ");
823 return -NF_ACCEPT;
824 }
825
826 /* Checksum invalid? Ignore.
827 * We skip checking packets on the outgoing path
828 * because the semantic of CHECKSUM_HW is different there
829 * and moreover root might send raw packets.
830 */
831 /* FIXME: Source route IP option packets --RR */
832 if (((pf == PF_INET && hooknum == NF_IP_PRE_ROUTING) ||
833 (pf == PF_INET6 && hooknum == NF_IP6_PRE_ROUTING))
834 && skb->ip_summed != CHECKSUM_UNNECESSARY
835 && csum(skb, dataoff)) {
836 if (LOG_INVALID(IPPROTO_TCP))
837 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
838 "nf_ct_tcp: bad TCP checksum ");
839 return -NF_ACCEPT;
840 }
841
842 /* Check TCP flags. */
843 tcpflags = (((u_int8_t *)th)[13] & ~(TH_ECE|TH_CWR));
844 if (!tcp_valid_flags[tcpflags]) {
845 if (LOG_INVALID(IPPROTO_TCP))
846 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
847 "nf_ct_tcp: invalid TCP flag combination ");
848 return -NF_ACCEPT;
849 }
850
851 return NF_ACCEPT;
852}
853
854static int csum4(const struct sk_buff *skb, unsigned int dataoff)
855{
856 return csum_tcpudp_magic(skb->nh.iph->saddr, skb->nh.iph->daddr,
857 skb->len - dataoff, IPPROTO_TCP,
858 skb->ip_summed == CHECKSUM_HW ? skb->csum
859 : skb_checksum(skb, dataoff,
860 skb->len - dataoff, 0));
861}
862
863static int csum6(const struct sk_buff *skb, unsigned int dataoff)
864{
865 return csum_ipv6_magic(&skb->nh.ipv6h->saddr, &skb->nh.ipv6h->daddr,
866 skb->len - dataoff, IPPROTO_TCP,
7c6de058
YK		 867 skb->ip_summed == CHECKSUM_HW
868 ? csum_sub(skb->csum,
869 skb_checksum(skb, 0, dataoff, 0))
9fb9cbb1
YK		 870 : skb_checksum(skb, dataoff, skb->len - dataoff,
871 0));
872}
873
874static int tcp_error4(struct sk_buff *skb,
875 unsigned int dataoff,
876 enum ip_conntrack_info *ctinfo,
877 int pf,
878 unsigned int hooknum)
879{
880 return tcp_error(skb, dataoff, ctinfo, pf, hooknum, csum4);
881}
882
883static int tcp_error6(struct sk_buff *skb,
884 unsigned int dataoff,
885 enum ip_conntrack_info *ctinfo,
886 int pf,
887 unsigned int hooknum)
888{
889 return tcp_error(skb, dataoff, ctinfo, pf, hooknum, csum6);
890}
891
892/* Returns verdict for packet, or -1 for invalid. */
893static int tcp_packet(struct nf_conn *conntrack,
894 const struct sk_buff *skb,
895 unsigned int dataoff,
896 enum ip_conntrack_info ctinfo,
897 int pf,
898 unsigned int hooknum)
899{
900 enum tcp_conntrack new_state, old_state;
901 enum ip_conntrack_dir dir;
902 struct tcphdr *th, _tcph;
903 unsigned long timeout;
904 unsigned int index;
905
906 th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph);
907 BUG_ON(th == NULL);
908
909 write_lock_bh(&tcp_lock);
910 old_state = conntrack->proto.tcp.state;
911 dir = CTINFO2DIR(ctinfo);
912 index = get_conntrack_index(th);
913 new_state = tcp_conntracks[dir][index][old_state];
914
915 switch (new_state) {
916 case TCP_CONNTRACK_IGNORE:
73f30602
JK		 917 /* Ignored packets:
918 *
919 * a) SYN in ORIGINAL
920 * b) SYN/ACK in REPLY
921 * c) ACK in reply direction after initial SYN in original.
922 */
9fb9cbb1
YK		 923 if (index == TCP_SYNACK_SET
924 && conntrack->proto.tcp.last_index == TCP_SYN_SET
925 && conntrack->proto.tcp.last_dir != dir
926 && ntohl(th->ack_seq) ==
927 conntrack->proto.tcp.last_end) {
928 /* This SYN/ACK acknowledges a SYN that we earlier
929 * ignored as invalid. This means that the client and
930 * the server are both in sync, while the firewall is
931 * not. We kill this session and block the SYN/ACK so
932 * that the client cannot but retransmit its SYN and
933 * thus initiate a clean new session.
934 */
935 write_unlock_bh(&tcp_lock);
936 if (LOG_INVALID(IPPROTO_TCP))
937 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
938 "nf_ct_tcp: killing out of sync session ");
939 if (del_timer(&conntrack->timeout))
940 conntrack->timeout.function((unsigned long)
941 conntrack);
942 return -NF_DROP;
943 }
944 conntrack->proto.tcp.last_index = index;
945 conntrack->proto.tcp.last_dir = dir;
946 conntrack->proto.tcp.last_seq = ntohl(th->seq);
947 conntrack->proto.tcp.last_end =
948 segment_seq_plus_len(ntohl(th->seq), skb->len, dataoff, th);
949
950 write_unlock_bh(&tcp_lock);
951 if (LOG_INVALID(IPPROTO_TCP))
952 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
953 "nf_ct_tcp: invalid packed ignored ");
954 return NF_ACCEPT;
955 case TCP_CONNTRACK_MAX:
956 /* Invalid packet */
957 DEBUGP("nf_ct_tcp: Invalid dir=%i index=%u ostate=%u\n",
958 dir, get_conntrack_index(th),
959 old_state);
960 write_unlock_bh(&tcp_lock);
961 if (LOG_INVALID(IPPROTO_TCP))
962 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
963 "nf_ct_tcp: invalid state ");
964 return -NF_ACCEPT;
965 case TCP_CONNTRACK_SYN_SENT:
966 if (old_state < TCP_CONNTRACK_TIME_WAIT)
967 break;
968 if ((conntrack->proto.tcp.seen[dir].flags &
969 IP_CT_TCP_FLAG_CLOSE_INIT)
970 || after(ntohl(th->seq),
971 conntrack->proto.tcp.seen[dir].td_end)) {
972 /* Attempt to reopen a closed connection.
973 * Delete this connection and look up again. */
974 write_unlock_bh(&tcp_lock);
975 if (del_timer(&conntrack->timeout))
976 conntrack->timeout.function((unsigned long)
977 conntrack);
978 return -NF_REPEAT;
3746a2b1
KK		 979 } else {
980 write_unlock_bh(&tcp_lock);
981 if (LOG_INVALID(IPPROTO_TCP))
982 nf_log_packet(pf, 0, skb, NULL, NULL,
983 NULL, "nf_ct_tcp: invalid SYN");
984 return -NF_ACCEPT;
9fb9cbb1
YK		 985 }
986 case TCP_CONNTRACK_CLOSE:
987 if (index == TCP_RST_SET
73f30602
JK		 988 && ((test_bit(IPS_SEEN_REPLY_BIT, &conntrack->status)
989 && conntrack->proto.tcp.last_index == TCP_SYN_SET)
990 || (!test_bit(IPS_ASSURED_BIT, &conntrack->status)
991 && conntrack->proto.tcp.last_index == TCP_ACK_SET))
9fb9cbb1 992 && ntohl(th->ack_seq) == conntrack->proto.tcp.last_end) {
93b1fae4 993 /* RST sent to invalid SYN or ACK we had let through
73f30602
JK		 994 * at a) and c) above:
995 *
996 * a) SYN was in window then
997 * c) we hold a half-open connection.
998 *
999 * Delete our connection entry.
9fb9cbb1 1000 * We skip window checking, because packet might ACK
73f30602 1001 * segments we ignored. */
9fb9cbb1
YK		 1002 goto in_window;
1003 }
93b1fae4 1004 /* Just fall through */
9fb9cbb1
YK		 1005 default:
1006 /* Keep compilers happy. */
1007 break;
1008 }
1009
1010 if (!tcp_in_window(&conntrack->proto.tcp, dir, index,
1011 skb, dataoff, th, pf)) {
1012 write_unlock_bh(&tcp_lock);
1013 return -NF_ACCEPT;
1014 }
1015 in_window:
1016 /* From now on we have got in-window packets */
1017 conntrack->proto.tcp.last_index = index;
1018
1019 DEBUGP("tcp_conntracks: src=%u.%u.%u.%u:%hu dst=%u.%u.%u.%u:%hu "
1020 "syn=%i ack=%i fin=%i rst=%i old=%i new=%i\n",
1021 NIPQUAD(iph->saddr), ntohs(th->source),
1022 NIPQUAD(iph->daddr), ntohs(th->dest),
1023 (th->syn ? 1 : 0), (th->ack ? 1 : 0),
1024 (th->fin ? 1 : 0), (th->rst ? 1 : 0),
1025 old_state, new_state);
1026
1027 conntrack->proto.tcp.state = new_state;
1028 if (old_state != new_state
1029 && (new_state == TCP_CONNTRACK_FIN_WAIT
1030 || new_state == TCP_CONNTRACK_CLOSE))
1031 conntrack->proto.tcp.seen[dir].flags |= IP_CT_TCP_FLAG_CLOSE_INIT;
1032 timeout = conntrack->proto.tcp.retrans >= nf_ct_tcp_max_retrans
1033 && *tcp_timeouts[new_state] > nf_ct_tcp_timeout_max_retrans
1034 ? nf_ct_tcp_timeout_max_retrans : *tcp_timeouts[new_state];
1035 write_unlock_bh(&tcp_lock);
1036
1037 nf_conntrack_event_cache(IPCT_PROTOINFO_VOLATILE, skb);
1038 if (new_state != old_state)
1039 nf_conntrack_event_cache(IPCT_PROTOINFO, skb);
1040
1041 if (!test_bit(IPS_SEEN_REPLY_BIT, &conntrack->status)) {
1042 /* If only reply is a RST, we can consider ourselves not to
1043 have an established connection: this is a fairly common
1044 problem case, so we can delete the conntrack
1045 immediately. --RR */
1046 if (th->rst) {
1047 if (del_timer(&conntrack->timeout))
1048 conntrack->timeout.function((unsigned long)
1049 conntrack);
1050 return NF_ACCEPT;
1051 }
1052 } else if (!test_bit(IPS_ASSURED_BIT, &conntrack->status)
1053 && (old_state == TCP_CONNTRACK_SYN_RECV
1054 || old_state == TCP_CONNTRACK_ESTABLISHED)
1055 && new_state == TCP_CONNTRACK_ESTABLISHED) {
1056 /* Set ASSURED if we see see valid ack in ESTABLISHED
1057 after SYN_RECV or a valid answer for a picked up
1058 connection. */
1059 set_bit(IPS_ASSURED_BIT, &conntrack->status);
1060 nf_conntrack_event_cache(IPCT_STATUS, skb);
1061 }
1062 nf_ct_refresh_acct(conntrack, ctinfo, skb, timeout);
1063
1064 return NF_ACCEPT;
1065}
1066
1067/* Called when a new connection for this protocol found. */
1068static int tcp_new(struct nf_conn *conntrack,
1069 const struct sk_buff *skb,
1070 unsigned int dataoff)
1071{
1072 enum tcp_conntrack new_state;
1073 struct tcphdr *th, _tcph;
1074#ifdef DEBUGP_VARS
1075 struct ip_ct_tcp_state *sender = &conntrack->proto.tcp.seen[0];
1076 struct ip_ct_tcp_state *receiver = &conntrack->proto.tcp.seen[1];
1077#endif
1078
1079 th = skb_header_pointer(skb, dataoff, 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("nf_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 dataoff, 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, dataoff, 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 (nf_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 dataoff, 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 = nf_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}
c1d10adb
PNA		 1152
1153#if defined(CONFIG_NF_CT_NETLINK) || \
1154 defined(CONFIG_NF_CT_NETLINK_MODULE)
1155
1156#include <linux/netfilter/nfnetlink.h>
1157#include <linux/netfilter/nfnetlink_conntrack.h>
1158
1159static int tcp_to_nfattr(struct sk_buff *skb, struct nfattr *nfa,
1160 const struct nf_conn *ct)
1161{
1162 struct nfattr *nest_parms;
1163
1164 read_lock_bh(&tcp_lock);
1165 nest_parms = NFA_NEST(skb, CTA_PROTOINFO_TCP);
1166 NFA_PUT(skb, CTA_PROTOINFO_TCP_STATE, sizeof(u_int8_t),
1167 &ct->proto.tcp.state);
1168 read_unlock_bh(&tcp_lock);
1169
1170 NFA_NEST_END(skb, nest_parms);
1171
1172 return 0;
1173
1174nfattr_failure:
1175 read_unlock_bh(&tcp_lock);
1176 return -1;
1177}
1178
1179static const size_t cta_min_tcp[CTA_PROTOINFO_TCP_MAX] = {
1180 [CTA_PROTOINFO_TCP_STATE-1] = sizeof(u_int8_t),
1181};
1182
1183static int nfattr_to_tcp(struct nfattr *cda[], struct nf_conn *ct)
1184{
1185 struct nfattr *attr = cda[CTA_PROTOINFO_TCP-1];
1186 struct nfattr *tb[CTA_PROTOINFO_TCP_MAX];
1187
1188 /* updates could not contain anything about the private
1189 * protocol info, in that case skip the parsing */
1190 if (!attr)
1191 return 0;
1192
1193 nfattr_parse_nested(tb, CTA_PROTOINFO_TCP_MAX, attr);
1194
1195 if (nfattr_bad_size(tb, CTA_PROTOINFO_TCP_MAX, cta_min_tcp))
1196 return -EINVAL;
1197
1198 if (!tb[CTA_PROTOINFO_TCP_STATE-1])
1199 return -EINVAL;
1200
1201 write_lock_bh(&tcp_lock);
1202 ct->proto.tcp.state =
1203 *(u_int8_t *)NFA_DATA(tb[CTA_PROTOINFO_TCP_STATE-1]);
1204 write_unlock_bh(&tcp_lock);
1205
1206 return 0;
1207}
1208#endif
9fb9cbb1
YK		 1209
1210struct nf_conntrack_protocol nf_conntrack_protocol_tcp4 =
1211{
1212 .l3proto = PF_INET,
1213 .proto = IPPROTO_TCP,
1214 .name = "tcp",
1215 .pkt_to_tuple = tcp_pkt_to_tuple,
1216 .invert_tuple = tcp_invert_tuple,
1217 .print_tuple = tcp_print_tuple,
1218 .print_conntrack = tcp_print_conntrack,
1219 .packet = tcp_packet,
1220 .new = tcp_new,
1221 .error = tcp_error4,
c1d10adb
PNA		 1222#if defined(CONFIG_NF_CT_NETLINK) || \
1223 defined(CONFIG_NF_CT_NETLINK_MODULE)
1224 .to_nfattr = tcp_to_nfattr,
1225 .from_nfattr = nfattr_to_tcp,
1226 .tuple_to_nfattr = nf_ct_port_tuple_to_nfattr,
1227 .nfattr_to_tuple = nf_ct_port_nfattr_to_tuple,
1228#endif
9fb9cbb1
YK		 1229};
1230
1231struct nf_conntrack_protocol nf_conntrack_protocol_tcp6 =
1232{
1233 .l3proto = PF_INET6,
1234 .proto = IPPROTO_TCP,
1235 .name = "tcp",
1236 .pkt_to_tuple = tcp_pkt_to_tuple,
1237 .invert_tuple = tcp_invert_tuple,
1238 .print_tuple = tcp_print_tuple,
1239 .print_conntrack = tcp_print_conntrack,
1240 .packet = tcp_packet,
1241 .new = tcp_new,
1242 .error = tcp_error6,
c1d10adb
PNA		 1243#if defined(CONFIG_NF_CT_NETLINK) || \
1244 defined(CONFIG_NF_CT_NETLINK_MODULE)
1245 .to_nfattr = tcp_to_nfattr,
1246 .from_nfattr = nfattr_to_tcp,
1247 .tuple_to_nfattr = nf_ct_port_tuple_to_nfattr,
1248 .nfattr_to_tuple = nf_ct_port_nfattr_to_tuple,
1249#endif
9fb9cbb1
YK		 1250};
1251
1252EXPORT_SYMBOL(nf_conntrack_protocol_tcp4);
1253EXPORT_SYMBOL(nf_conntrack_protocol_tcp6);
Linux 6.x block layer and io_uring tree(s)