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[NETFILTER]: xt_helper: use RCU
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / net / netfilter / nf_conntrack_proto_tcp.c
CommitLineData
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.
9fb9cbb1
YK		 7 */
8
9fb9cbb1 9#include <linux/types.h>
9fb9cbb1
YK		 10#include <linux/timer.h>
11#include <linux/netfilter.h>
12#include <linux/module.h>
13#include <linux/in.h>
14#include <linux/tcp.h>
15#include <linux/spinlock.h>
16#include <linux/skbuff.h>
17#include <linux/ipv6.h>
18#include <net/ip6_checksum.h>
19
20#include <net/tcp.h>
21
22#include <linux/netfilter.h>
23#include <linux/netfilter_ipv4.h>
24#include <linux/netfilter_ipv6.h>
25#include <net/netfilter/nf_conntrack.h>
605dcad6 26#include <net/netfilter/nf_conntrack_l4proto.h>
f6180121 27#include <net/netfilter/nf_conntrack_ecache.h>
9fb9cbb1
YK		 28
29#if 0
30#define DEBUGP printk
31#define DEBUGP_VARS
32#else
33#define DEBUGP(format, args...)
34#endif
35
36/* Protects conntrack->proto.tcp */
37static DEFINE_RWLOCK(tcp_lock);
38
601e68e1
YH		 39/* "Be conservative in what you do,
40 be liberal in what you accept from others."
9fb9cbb1 41 If it's non-zero, we mark only out of window RST segments as INVALID. */
3aef0fd9 42static int nf_ct_tcp_be_liberal __read_mostly = 0;
9fb9cbb1 43
a09113c2 44/* If it is set to zero, we disable picking up already established
9fb9cbb1 45 connections. */
3aef0fd9 46static int nf_ct_tcp_loose __read_mostly = 1;
9fb9cbb1 47
601e68e1
YH		 48/* Max number of the retransmitted packets without receiving an (acceptable)
49 ACK from the destination. If this number is reached, a shorter timer
9fb9cbb1 50 will be started. */
3aef0fd9 51static int nf_ct_tcp_max_retrans __read_mostly = 3;
9fb9cbb1
YK		 52
53 /* FIXME: Examine ipfilter's timeouts and conntrack transitions more
54 closely. They're more complex. --RR */
55
56static const char *tcp_conntrack_names[] = {
57 "NONE",
58 "SYN_SENT",
59 "SYN_RECV",
60 "ESTABLISHED",
61 "FIN_WAIT",
62 "CLOSE_WAIT",
63 "LAST_ACK",
64 "TIME_WAIT",
65 "CLOSE",
66 "LISTEN"
67};
601e68e1 68
9fb9cbb1
YK		 69#define SECS * HZ
70#define MINS * 60 SECS
71#define HOURS * 60 MINS
72#define DAYS * 24 HOURS
73
933a41e7
PM		 74static unsigned int nf_ct_tcp_timeout_syn_sent __read_mostly = 2 MINS;
75static unsigned int nf_ct_tcp_timeout_syn_recv __read_mostly = 60 SECS;
76static unsigned int nf_ct_tcp_timeout_established __read_mostly = 5 DAYS;
77static unsigned int nf_ct_tcp_timeout_fin_wait __read_mostly = 2 MINS;
78static unsigned int nf_ct_tcp_timeout_close_wait __read_mostly = 60 SECS;
79static unsigned int nf_ct_tcp_timeout_last_ack __read_mostly = 30 SECS;
80static unsigned int nf_ct_tcp_timeout_time_wait __read_mostly = 2 MINS;
81static unsigned int nf_ct_tcp_timeout_close __read_mostly = 10 SECS;
9fb9cbb1
YK		 82
83/* RFC1122 says the R2 limit should be at least 100 seconds.
601e68e1 84 Linux uses 15 packets as limit, which corresponds
9fb9cbb1 85 to ~13-30min depending on RTO. */
933a41e7 86static unsigned int nf_ct_tcp_timeout_max_retrans __read_mostly = 5 MINS;
601e68e1 87
933a41e7
PM		 88static unsigned int * tcp_timeouts[] = {
89 NULL, /* TCP_CONNTRACK_NONE */
9fb9cbb1
YK		 90 &nf_ct_tcp_timeout_syn_sent, /* TCP_CONNTRACK_SYN_SENT, */
91 &nf_ct_tcp_timeout_syn_recv, /* TCP_CONNTRACK_SYN_RECV, */
92 &nf_ct_tcp_timeout_established, /* TCP_CONNTRACK_ESTABLISHED, */
93 &nf_ct_tcp_timeout_fin_wait, /* TCP_CONNTRACK_FIN_WAIT, */
94 &nf_ct_tcp_timeout_close_wait, /* TCP_CONNTRACK_CLOSE_WAIT, */
95 &nf_ct_tcp_timeout_last_ack, /* TCP_CONNTRACK_LAST_ACK, */
96 &nf_ct_tcp_timeout_time_wait, /* TCP_CONNTRACK_TIME_WAIT, */
97 &nf_ct_tcp_timeout_close, /* TCP_CONNTRACK_CLOSE, */
98 NULL, /* TCP_CONNTRACK_LISTEN */
99 };
601e68e1 100
9fb9cbb1
YK		 101#define sNO TCP_CONNTRACK_NONE
102#define sSS TCP_CONNTRACK_SYN_SENT
103#define sSR TCP_CONNTRACK_SYN_RECV
104#define sES TCP_CONNTRACK_ESTABLISHED
105#define sFW TCP_CONNTRACK_FIN_WAIT
106#define sCW TCP_CONNTRACK_CLOSE_WAIT
107#define sLA TCP_CONNTRACK_LAST_ACK
108#define sTW TCP_CONNTRACK_TIME_WAIT
109#define sCL TCP_CONNTRACK_CLOSE
110#define sLI TCP_CONNTRACK_LISTEN
111#define sIV TCP_CONNTRACK_MAX
112#define sIG TCP_CONNTRACK_IGNORE
113
114/* What TCP flags are set from RST/SYN/FIN/ACK. */
115enum tcp_bit_set {
116 TCP_SYN_SET,
117 TCP_SYNACK_SET,
118 TCP_FIN_SET,
119 TCP_ACK_SET,
120 TCP_RST_SET,
121 TCP_NONE_SET,
122};
601e68e1 123
9fb9cbb1
YK		 124/*
125 * The TCP state transition table needs a few words...
126 *
127 * We are the man in the middle. All the packets go through us
128 * but might get lost in transit to the destination.
601e68e1 129 * It is assumed that the destinations can't receive segments
9fb9cbb1
YK		 130 * we haven't seen.
131 *
132 * The checked segment is in window, but our windows are *not*
133 * equivalent with the ones of the sender/receiver. We always
134 * try to guess the state of the current sender.
135 *
136 * The meaning of the states are:
137 *
138 * NONE: initial state
601e68e1 139 * SYN_SENT: SYN-only packet seen
9fb9cbb1
YK		 140 * SYN_RECV: SYN-ACK packet seen
141 * ESTABLISHED: ACK packet seen
142 * FIN_WAIT: FIN packet seen
601e68e1 143 * CLOSE_WAIT: ACK seen (after FIN)
9fb9cbb1
YK		 144 * LAST_ACK: FIN seen (after FIN)
145 * TIME_WAIT: last ACK seen
146 * CLOSE: closed connection
147 *
148 * LISTEN state is not used.
149 *
150 * Packets marked as IGNORED (sIG):
601e68e1
YH		 151 * if they may be either invalid or valid
152 * and the receiver may send back a connection
9fb9cbb1
YK		 153 * closing RST or a SYN/ACK.
154 *
155 * Packets marked as INVALID (sIV):
156 * if they are invalid
157 * or we do not support the request (simultaneous open)
158 */
159static enum tcp_conntrack tcp_conntracks[2][6][TCP_CONNTRACK_MAX] = {
160 {
161/* ORIGINAL */
162/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
163/*syn*/ { sSS, sSS, sIG, sIG, sIG, sIG, sIG, sSS, sSS, sIV },
164/*
165 * sNO -> sSS Initialize a new connection
166 * sSS -> sSS Retransmitted SYN
167 * sSR -> sIG Late retransmitted SYN?
168 * sES -> sIG Error: SYNs in window outside the SYN_SENT state
601e68e1 169 * are errors. Receiver will reply with RST
9fb9cbb1
YK		 170 * and close the connection.
171 * Or we are not in sync and hold a dead connection.
172 * sFW -> sIG
173 * sCW -> sIG
174 * sLA -> sIG
175 * sTW -> sSS Reopened connection (RFC 1122).
176 * sCL -> sSS
177 */
178/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
179/*synack*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV },
180/*
181 * A SYN/ACK from the client is always invalid:
601e68e1 182 * - either it tries to set up a simultaneous open, which is
9fb9cbb1
YK		 183 * not supported;
184 * - or the firewall has just been inserted between the two hosts
601e68e1 185 * during the session set-up. The SYN will be retransmitted
9fb9cbb1
YK		 186 * by the true client (or it'll time out).
187 */
188/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
189/*fin*/ { sIV, sIV, sFW, sFW, sLA, sLA, sLA, sTW, sCL, sIV },
190/*
191 * sNO -> sIV Too late and no reason to do anything...
192 * sSS -> sIV Client migth not send FIN in this state:
193 * we enforce waiting for a SYN/ACK reply first.
194 * sSR -> sFW Close started.
195 * sES -> sFW
196 * sFW -> sLA FIN seen in both directions, waiting for
601e68e1 197 * the last ACK.
9fb9cbb1
YK		 198 * Migth be a retransmitted FIN as well...
199 * sCW -> sLA
200 * sLA -> sLA Retransmitted FIN. Remain in the same state.
201 * sTW -> sTW
202 * sCL -> sCL
203 */
204/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
205/*ack*/ { sES, sIV, sES, sES, sCW, sCW, sTW, sTW, sCL, sIV },
206/*
207 * sNO -> sES Assumed.
208 * sSS -> sIV ACK is invalid: we haven't seen a SYN/ACK yet.
209 * sSR -> sES Established state is reached.
210 * sES -> sES :-)
211 * sFW -> sCW Normal close request answered by ACK.
212 * sCW -> sCW
213 * sLA -> sTW Last ACK detected.
214 * sTW -> sTW Retransmitted last ACK. Remain in the same state.
215 * sCL -> sCL
216 */
217/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
218/*rst*/ { sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sIV },
219/*none*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV }
220 },
221 {
222/* REPLY */
223/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
224/*syn*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV },
225/*
226 * sNO -> sIV Never reached.
227 * sSS -> sIV Simultaneous open, not supported
228 * sSR -> sIV Simultaneous open, not supported.
229 * sES -> sIV Server may not initiate a connection.
230 * sFW -> sIV
231 * sCW -> sIV
232 * sLA -> sIV
233 * sTW -> sIV Reopened connection, but server may not do it.
234 * sCL -> sIV
235 */
236/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
237/*synack*/ { sIV, sSR, sSR, sIG, sIG, sIG, sIG, sIG, sIG, sIV },
238/*
239 * sSS -> sSR Standard open.
240 * sSR -> sSR Retransmitted SYN/ACK.
241 * sES -> sIG Late retransmitted SYN/ACK?
242 * sFW -> sIG Might be SYN/ACK answering ignored SYN
243 * sCW -> sIG
244 * sLA -> sIG
245 * sTW -> sIG
246 * sCL -> sIG
247 */
248/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
249/*fin*/ { sIV, sIV, sFW, sFW, sLA, sLA, sLA, sTW, sCL, sIV },
250/*
251 * sSS -> sIV Server might not send FIN in this state.
252 * sSR -> sFW Close started.
253 * sES -> sFW
254 * sFW -> sLA FIN seen in both directions.
255 * sCW -> sLA
256 * sLA -> sLA Retransmitted FIN.
257 * sTW -> sTW
258 * sCL -> sCL
259 */
260/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
73f30602 261/*ack*/ { sIV, sIG, sSR, sES, sCW, sCW, sTW, sTW, sCL, sIV },
9fb9cbb1 262/*
73f30602 263 * sSS -> sIG Might be a half-open connection.
9fb9cbb1
YK		 264 * sSR -> sSR Might answer late resent SYN.
265 * sES -> sES :-)
266 * sFW -> sCW Normal close request answered by ACK.
267 * sCW -> sCW
268 * sLA -> sTW Last ACK detected.
269 * sTW -> sTW Retransmitted last ACK.
270 * sCL -> sCL
271 */
272/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */
273/*rst*/ { sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sIV },
274/*none*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV }
601e68e1 275 }
9fb9cbb1
YK		 276};
277
278static int tcp_pkt_to_tuple(const struct sk_buff *skb,
279 unsigned int dataoff,
280 struct nf_conntrack_tuple *tuple)
281{
282 struct tcphdr _hdr, *hp;
283
284 /* Actually only need first 8 bytes. */
285 hp = skb_header_pointer(skb, dataoff, 8, &_hdr);
286 if (hp == NULL)
287 return 0;
288
289 tuple->src.u.tcp.port = hp->source;
290 tuple->dst.u.tcp.port = hp->dest;
291
292 return 1;
293}
294
295static int tcp_invert_tuple(struct nf_conntrack_tuple *tuple,
296 const struct nf_conntrack_tuple *orig)
297{
298 tuple->src.u.tcp.port = orig->dst.u.tcp.port;
299 tuple->dst.u.tcp.port = orig->src.u.tcp.port;
300 return 1;
301}
302
303/* Print out the per-protocol part of the tuple. */
304static int tcp_print_tuple(struct seq_file *s,
305 const struct nf_conntrack_tuple *tuple)
306{
307 return seq_printf(s, "sport=%hu dport=%hu ",
308 ntohs(tuple->src.u.tcp.port),
309 ntohs(tuple->dst.u.tcp.port));
310}
311
312/* Print out the private part of the conntrack. */
313static int tcp_print_conntrack(struct seq_file *s,
314 const struct nf_conn *conntrack)
315{
316 enum tcp_conntrack state;
317
318 read_lock_bh(&tcp_lock);
319 state = conntrack->proto.tcp.state;
320 read_unlock_bh(&tcp_lock);
321
322 return seq_printf(s, "%s ", tcp_conntrack_names[state]);
323}
324
325static unsigned int get_conntrack_index(const struct tcphdr *tcph)
326{
327 if (tcph->rst) return TCP_RST_SET;
328 else if (tcph->syn) return (tcph->ack ? TCP_SYNACK_SET : TCP_SYN_SET);
329 else if (tcph->fin) return TCP_FIN_SET;
330 else if (tcph->ack) return TCP_ACK_SET;
331 else return TCP_NONE_SET;
332}
333
334/* TCP connection tracking based on 'Real Stateful TCP Packet Filtering
335 in IP Filter' by Guido van Rooij.
601e68e1 336
9fb9cbb1
YK		 337 http://www.nluug.nl/events/sane2000/papers.html
338 http://www.iae.nl/users/guido/papers/tcp_filtering.ps.gz
601e68e1 339
9fb9cbb1
YK		 340 The boundaries and the conditions are changed according to RFC793:
341 the packet must intersect the window (i.e. segments may be
342 after the right or before the left edge) and thus receivers may ACK
343 segments after the right edge of the window.
344
601e68e1 345 td_maxend = max(sack + max(win,1)) seen in reply packets
9fb9cbb1
YK		 346 td_maxwin = max(max(win, 1)) + (sack - ack) seen in sent packets
347 td_maxwin += seq + len - sender.td_maxend
348 if seq + len > sender.td_maxend
349 td_end = max(seq + len) seen in sent packets
601e68e1 350
9fb9cbb1
YK		 351 I. Upper bound for valid data: seq <= sender.td_maxend
352 II. Lower bound for valid data: seq + len >= sender.td_end - receiver.td_maxwin
353 III. Upper bound for valid ack: sack <= receiver.td_end
354 IV. Lower bound for valid ack: ack >= receiver.td_end - MAXACKWINDOW
355
356 where sack is the highest right edge of sack block found in the packet.
357
601e68e1
YH		 358 The upper bound limit for a valid ack is not ignored -
359 we doesn't have to deal with fragments.
9fb9cbb1
YK		 360*/
361
362static inline __u32 segment_seq_plus_len(__u32 seq,
363 size_t len,
364 unsigned int dataoff,
365 struct tcphdr *tcph)
366{
367 /* XXX Should I use payload length field in IP/IPv6 header ?
368 * - YK */
369 return (seq + len - dataoff - tcph->doff*4
370 + (tcph->syn ? 1 : 0) + (tcph->fin ? 1 : 0));
371}
601e68e1 372
9fb9cbb1
YK		 373/* Fixme: what about big packets? */
374#define MAXACKWINCONST 66000
375#define MAXACKWINDOW(sender) \
376 ((sender)->td_maxwin > MAXACKWINCONST ? (sender)->td_maxwin \
377 : MAXACKWINCONST)
601e68e1 378
9fb9cbb1
YK		 379/*
380 * Simplified tcp_parse_options routine from tcp_input.c
381 */
382static void tcp_options(const struct sk_buff *skb,
383 unsigned int dataoff,
601e68e1 384 struct tcphdr *tcph,
9fb9cbb1
YK		 385 struct ip_ct_tcp_state *state)
386{
387 unsigned char buff[(15 * 4) - sizeof(struct tcphdr)];
388 unsigned char *ptr;
389 int length = (tcph->doff*4) - sizeof(struct tcphdr);
390
391 if (!length)
392 return;
393
394 ptr = skb_header_pointer(skb, dataoff + sizeof(struct tcphdr),
395 length, buff);
396 BUG_ON(ptr == NULL);
397
601e68e1 398 state->td_scale =
9fb9cbb1
YK		 399 state->flags = 0;
400
401 while (length > 0) {
402 int opcode=*ptr++;
403 int opsize;
404
405 switch (opcode) {
406 case TCPOPT_EOL:
407 return;
408 case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */
409 length--;
410 continue;
411 default:
412 opsize=*ptr++;
413 if (opsize < 2) /* "silly options" */
414 return;
415 if (opsize > length)
416 break; /* don't parse partial options */
417
601e68e1 418 if (opcode == TCPOPT_SACK_PERM
9fb9cbb1
YK		 419 && opsize == TCPOLEN_SACK_PERM)
420 state->flags |= IP_CT_TCP_FLAG_SACK_PERM;
421 else if (opcode == TCPOPT_WINDOW
422 && opsize == TCPOLEN_WINDOW) {
423 state->td_scale = *(u_int8_t *)ptr;
424
425 if (state->td_scale > 14) {
426 /* See RFC1323 */
427 state->td_scale = 14;
428 }
429 state->flags |=
430 IP_CT_TCP_FLAG_WINDOW_SCALE;
431 }
432 ptr += opsize - 2;
433 length -= opsize;
434 }
435 }
436}
437
438static void tcp_sack(const struct sk_buff *skb, unsigned int dataoff,
439 struct tcphdr *tcph, __u32 *sack)
440{
601e68e1 441 unsigned char buff[(15 * 4) - sizeof(struct tcphdr)];
9fb9cbb1
YK		 442 unsigned char *ptr;
443 int length = (tcph->doff*4) - sizeof(struct tcphdr);
444 __u32 tmp;
445
446 if (!length)
447 return;
448
449 ptr = skb_header_pointer(skb, dataoff + sizeof(struct tcphdr),
450 length, buff);
451 BUG_ON(ptr == NULL);
452
453 /* Fast path for timestamp-only option */
454 if (length == TCPOLEN_TSTAMP_ALIGNED*4
8f05ce91
YH		 455 && *(__be32 *)ptr == htonl((TCPOPT_NOP << 24)
456 | (TCPOPT_NOP << 16)
457 | (TCPOPT_TIMESTAMP << 8)
458 | TCPOLEN_TIMESTAMP))
9fb9cbb1
YK		 459 return;
460
461 while (length > 0) {
462 int opcode = *ptr++;
463 int opsize, i;
464
465 switch (opcode) {
466 case TCPOPT_EOL:
467 return;
468 case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */
469 length--;
470 continue;
471 default:
472 opsize = *ptr++;
473 if (opsize < 2) /* "silly options" */
474 return;
475 if (opsize > length)
476 break; /* don't parse partial options */
477
601e68e1
YH		 478 if (opcode == TCPOPT_SACK
479 && opsize >= (TCPOLEN_SACK_BASE
480 + TCPOLEN_SACK_PERBLOCK)
481 && !((opsize - TCPOLEN_SACK_BASE)
482 % TCPOLEN_SACK_PERBLOCK)) {
483 for (i = 0;
484 i < (opsize - TCPOLEN_SACK_BASE);
485 i += TCPOLEN_SACK_PERBLOCK) {
486 tmp = ntohl(*((__be32 *)(ptr+i)+1));
9fb9cbb1
YK		 487
488 if (after(tmp, *sack))
489 *sack = tmp;
490 }
491 return;
492 }
493 ptr += opsize - 2;
494 length -= opsize;
495 }
496 }
497}
498
601e68e1
YH		 499static int tcp_in_window(struct ip_ct_tcp *state,
500 enum ip_conntrack_dir dir,
501 unsigned int index,
502 const struct sk_buff *skb,
9fb9cbb1 503 unsigned int dataoff,
601e68e1 504 struct tcphdr *tcph,
9fb9cbb1
YK		 505 int pf)
506{
507 struct ip_ct_tcp_state *sender = &state->seen[dir];
508 struct ip_ct_tcp_state *receiver = &state->seen[!dir];
509 __u32 seq, ack, sack, end, win, swin;
510 int res;
511
512 /*
513 * Get the required data from the packet.
514 */
515 seq = ntohl(tcph->seq);
516 ack = sack = ntohl(tcph->ack_seq);
517 win = ntohs(tcph->window);
518 end = segment_seq_plus_len(seq, skb->len, dataoff, tcph);
519
520 if (receiver->flags & IP_CT_TCP_FLAG_SACK_PERM)
521 tcp_sack(skb, dataoff, tcph, &sack);
522
523 DEBUGP("tcp_in_window: START\n");
524 DEBUGP("tcp_in_window: src=%u.%u.%u.%u:%hu dst=%u.%u.%u.%u:%hu "
525 "seq=%u ack=%u sack=%u win=%u end=%u\n",
601e68e1 526 NIPQUAD(iph->saddr), ntohs(tcph->source),
9fb9cbb1
YK		 527 NIPQUAD(iph->daddr), ntohs(tcph->dest),
528 seq, ack, sack, win, end);
529 DEBUGP("tcp_in_window: sender end=%u maxend=%u maxwin=%u scale=%i "
530 "receiver end=%u maxend=%u maxwin=%u scale=%i\n",
531 sender->td_end, sender->td_maxend, sender->td_maxwin,
601e68e1
YH		 532 sender->td_scale,
533 receiver->td_end, receiver->td_maxend, receiver->td_maxwin,
9fb9cbb1
YK		 534 receiver->td_scale);
535
536 if (sender->td_end == 0) {
537 /*
538 * Initialize sender data.
539 */
540 if (tcph->syn && tcph->ack) {
541 /*
542 * Outgoing SYN-ACK in reply to a SYN.
543 */
601e68e1 544 sender->td_end =
9fb9cbb1
YK		 545 sender->td_maxend = end;
546 sender->td_maxwin = (win == 0 ? 1 : win);
547
548 tcp_options(skb, dataoff, tcph, sender);
601e68e1 549 /*
9fb9cbb1
YK		 550 * RFC 1323:
551 * Both sides must send the Window Scale option
552 * to enable window scaling in either direction.
553 */
554 if (!(sender->flags & IP_CT_TCP_FLAG_WINDOW_SCALE
555 && receiver->flags & IP_CT_TCP_FLAG_WINDOW_SCALE))
601e68e1 556 sender->td_scale =
9fb9cbb1
YK		 557 receiver->td_scale = 0;
558 } else {
559 /*
560 * We are in the middle of a connection,
561 * its history is lost for us.
562 * Let's try to use the data from the packet.
601e68e1 563 */
9fb9cbb1
YK		 564 sender->td_end = end;
565 sender->td_maxwin = (win == 0 ? 1 : win);
566 sender->td_maxend = end + sender->td_maxwin;
567 }
568 } else if (((state->state == TCP_CONNTRACK_SYN_SENT
569 && dir == IP_CT_DIR_ORIGINAL)
570 || (state->state == TCP_CONNTRACK_SYN_RECV
571 && dir == IP_CT_DIR_REPLY))
572 && after(end, sender->td_end)) {
573 /*
574 * RFC 793: "if a TCP is reinitialized ... then it need
601e68e1 575 * not wait at all; it must only be sure to use sequence
9fb9cbb1
YK		 576 * numbers larger than those recently used."
577 */
578 sender->td_end =
579 sender->td_maxend = end;
580 sender->td_maxwin = (win == 0 ? 1 : win);
581
582 tcp_options(skb, dataoff, tcph, sender);
583 }
584
585 if (!(tcph->ack)) {
586 /*
587 * If there is no ACK, just pretend it was set and OK.
588 */
589 ack = sack = receiver->td_end;
601e68e1
YH		 590 } else if (((tcp_flag_word(tcph) & (TCP_FLAG_ACK|TCP_FLAG_RST)) ==
591 (TCP_FLAG_ACK|TCP_FLAG_RST))
9fb9cbb1
YK		 592 && (ack == 0)) {
593 /*
594 * Broken TCP stacks, that set ACK in RST packets as well
595 * with zero ack value.
596 */
597 ack = sack = receiver->td_end;
598 }
599
600 if (seq == end
601 && (!tcph->rst
602 || (seq == 0 && state->state == TCP_CONNTRACK_SYN_SENT)))
603 /*
604 * Packets contains no data: we assume it is valid
605 * and check the ack value only.
606 * However RST segments are always validated by their
607 * SEQ number, except when seq == 0 (reset sent answering
608 * SYN.
609 */
610 seq = end = sender->td_end;
611
612 DEBUGP("tcp_in_window: src=%u.%u.%u.%u:%hu dst=%u.%u.%u.%u:%hu "
613 "seq=%u ack=%u sack =%u win=%u end=%u\n",
614 NIPQUAD(iph->saddr), ntohs(tcph->source),
615 NIPQUAD(iph->daddr), ntohs(tcph->dest),
616 seq, ack, sack, win, end);
617 DEBUGP("tcp_in_window: sender end=%u maxend=%u maxwin=%u scale=%i "
618 "receiver end=%u maxend=%u maxwin=%u scale=%i\n",
619 sender->td_end, sender->td_maxend, sender->td_maxwin,
601e68e1 620 sender->td_scale,
9fb9cbb1
YK		 621 receiver->td_end, receiver->td_maxend, receiver->td_maxwin,
622 receiver->td_scale);
623
624 DEBUGP("tcp_in_window: I=%i II=%i III=%i IV=%i\n",
625 before(seq, sender->td_maxend + 1),
626 after(end, sender->td_end - receiver->td_maxwin - 1),
601e68e1
YH		 627 before(sack, receiver->td_end + 1),
628 after(ack, receiver->td_end - MAXACKWINDOW(sender)));
9fb9cbb1 629
a09113c2
PM		 630 if (before(seq, sender->td_maxend + 1) &&
631 after(end, sender->td_end - receiver->td_maxwin - 1) &&
632 before(sack, receiver->td_end + 1) &&
633 after(ack, receiver->td_end - MAXACKWINDOW(sender))) {
601e68e1 634 /*
9fb9cbb1
YK		 635 * Take into account window scaling (RFC 1323).
636 */
637 if (!tcph->syn)
638 win <<= sender->td_scale;
639
640 /*
641 * Update sender data.
642 */
643 swin = win + (sack - ack);
644 if (sender->td_maxwin < swin)
645 sender->td_maxwin = swin;
646 if (after(end, sender->td_end))
647 sender->td_end = end;
648 /*
649 * Update receiver data.
650 */
651 if (after(end, sender->td_maxend))
652 receiver->td_maxwin += end - sender->td_maxend;
653 if (after(sack + win, receiver->td_maxend - 1)) {
654 receiver->td_maxend = sack + win;
655 if (win == 0)
656 receiver->td_maxend++;
657 }
658
601e68e1 659 /*
9fb9cbb1
YK		 660 * Check retransmissions.
661 */
662 if (index == TCP_ACK_SET) {
663 if (state->last_dir == dir
664 && state->last_seq == seq
665 && state->last_ack == ack
c1fe3ca5
GH		 666 && state->last_end == end
667 && state->last_win == win)
9fb9cbb1
YK		 668 state->retrans++;
669 else {
670 state->last_dir = dir;
671 state->last_seq = seq;
672 state->last_ack = ack;
673 state->last_end = end;
c1fe3ca5 674 state->last_win = win;
9fb9cbb1
YK		 675 state->retrans = 0;
676 }
677 }
9fb9cbb1
YK		 678 res = 1;
679 } else {
a09113c2
PM		 680 res = 0;
681 if (sender->flags & IP_CT_TCP_FLAG_BE_LIBERAL ||
682 nf_ct_tcp_be_liberal)
683 res = 1;
684 if (!res && LOG_INVALID(IPPROTO_TCP))
9fb9cbb1
YK		 685 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
686 "nf_ct_tcp: %s ",
687 before(seq, sender->td_maxend + 1) ?
688 after(end, sender->td_end - receiver->td_maxwin - 1) ?
689 before(sack, receiver->td_end + 1) ?
690 after(ack, receiver->td_end - MAXACKWINDOW(sender)) ? "BUG"
691 : "ACK is under the lower bound (possible overly delayed ACK)"
692 : "ACK is over the upper bound (ACKed data not seen yet)"
693 : "SEQ is under the lower bound (already ACKed data retransmitted)"
694 : "SEQ is over the upper bound (over the window of the receiver)");
601e68e1
YH		 695 }
696
9fb9cbb1
YK		 697 DEBUGP("tcp_in_window: res=%i sender end=%u maxend=%u maxwin=%u "
698 "receiver end=%u maxend=%u maxwin=%u\n",
601e68e1 699 res, sender->td_end, sender->td_maxend, sender->td_maxwin,
9fb9cbb1
YK		 700 receiver->td_end, receiver->td_maxend, receiver->td_maxwin);
701
702 return res;
703}
704
5b1158e9 705#ifdef CONFIG_NF_NAT_NEEDED
9fb9cbb1
YK		 706/* Update sender->td_end after NAT successfully mangled the packet */
707/* Caller must linearize skb at tcp header. */
708void nf_conntrack_tcp_update(struct sk_buff *skb,
709 unsigned int dataoff,
601e68e1 710 struct nf_conn *conntrack,
9fb9cbb1
YK		 711 int dir)
712{
713 struct tcphdr *tcph = (void *)skb->data + dataoff;
714 __u32 end;
715#ifdef DEBUGP_VARS
716 struct ip_ct_tcp_state *sender = &conntrack->proto.tcp.seen[dir];
717 struct ip_ct_tcp_state *receiver = &conntrack->proto.tcp.seen[!dir];
718#endif
719
720 end = segment_seq_plus_len(ntohl(tcph->seq), skb->len, dataoff, tcph);
721
722 write_lock_bh(&tcp_lock);
723 /*
724 * We have to worry for the ack in the reply packet only...
725 */
726 if (after(end, conntrack->proto.tcp.seen[dir].td_end))
727 conntrack->proto.tcp.seen[dir].td_end = end;
728 conntrack->proto.tcp.last_end = end;
729 write_unlock_bh(&tcp_lock);
730 DEBUGP("tcp_update: sender end=%u maxend=%u maxwin=%u scale=%i "
731 "receiver end=%u maxend=%u maxwin=%u scale=%i\n",
732 sender->td_end, sender->td_maxend, sender->td_maxwin,
601e68e1 733 sender->td_scale,
9fb9cbb1
YK		 734 receiver->td_end, receiver->td_maxend, receiver->td_maxwin,
735 receiver->td_scale);
736}
13b18339 737EXPORT_SYMBOL_GPL(nf_conntrack_tcp_update);
9fb9cbb1
YK		 738#endif
739
740#define TH_FIN 0x01
741#define TH_SYN 0x02
742#define TH_RST 0x04
743#define TH_PUSH 0x08
744#define TH_ACK 0x10
745#define TH_URG 0x20
746#define TH_ECE 0x40
747#define TH_CWR 0x80
748
5c8ce7c9
WT		 749/* table of valid flag combinations - PUSH, ECE and CWR are always valid */
750static u8 tcp_valid_flags[(TH_FIN|TH_SYN|TH_RST|TH_ACK|TH_URG) + 1] =
9fb9cbb1
YK		 751{
752 [TH_SYN] = 1,
d3ab4298 753 [TH_SYN|TH_URG] = 1,
d3ab4298 754 [TH_SYN|TH_ACK] = 1,
9fb9cbb1
YK		 755 [TH_RST] = 1,
756 [TH_RST|TH_ACK] = 1,
9fb9cbb1 757 [TH_FIN|TH_ACK] = 1,
5c8ce7c9 758 [TH_FIN|TH_ACK|TH_URG] = 1,
9fb9cbb1 759 [TH_ACK] = 1,
9fb9cbb1 760 [TH_ACK|TH_URG] = 1,
9fb9cbb1
YK		 761};
762
763/* Protect conntrack agaist broken packets. Code taken from ipt_unclean.c. */
764static int tcp_error(struct sk_buff *skb,
765 unsigned int dataoff,
766 enum ip_conntrack_info *ctinfo,
767 int pf,
96f6bf82 768 unsigned int hooknum)
9fb9cbb1
YK		 769{
770 struct tcphdr _tcph, *th;
771 unsigned int tcplen = skb->len - dataoff;
772 u_int8_t tcpflags;
773
774 /* Smaller that minimal TCP header? */
775 th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph);
776 if (th == NULL) {
777 if (LOG_INVALID(IPPROTO_TCP))
778 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
779 "nf_ct_tcp: short packet ");
780 return -NF_ACCEPT;
601e68e1
YH		 781 }
782
9fb9cbb1
YK		 783 /* Not whole TCP header or malformed packet */
784 if (th->doff*4 < sizeof(struct tcphdr) || tcplen < th->doff*4) {
785 if (LOG_INVALID(IPPROTO_TCP))
786 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
787 "nf_ct_tcp: truncated/malformed packet ");
788 return -NF_ACCEPT;
789 }
601e68e1 790
9fb9cbb1
YK		 791 /* Checksum invalid? Ignore.
792 * We skip checking packets on the outgoing path
84fa7933 793 * because the checksum is assumed to be correct.
9fb9cbb1
YK		 794 */
795 /* FIXME: Source route IP option packets --RR */
39a27a35
PM		 796 if (nf_conntrack_checksum &&
797 ((pf == PF_INET && hooknum == NF_IP_PRE_ROUTING) ||
798 (pf == PF_INET6 && hooknum == NF_IP6_PRE_ROUTING)) &&
96f6bf82 799 nf_checksum(skb, hooknum, dataoff, IPPROTO_TCP, pf)) {
9fb9cbb1
YK		 800 if (LOG_INVALID(IPPROTO_TCP))
801 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
802 "nf_ct_tcp: bad TCP checksum ");
803 return -NF_ACCEPT;
804 }
805
806 /* Check TCP flags. */
5c8ce7c9 807 tcpflags = (((u_int8_t *)th)[13] & ~(TH_ECE|TH_CWR|TH_PUSH));
9fb9cbb1
YK		 808 if (!tcp_valid_flags[tcpflags]) {
809 if (LOG_INVALID(IPPROTO_TCP))
810 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
811 "nf_ct_tcp: invalid TCP flag combination ");
812 return -NF_ACCEPT;
813 }
814
815 return NF_ACCEPT;
816}
817
9fb9cbb1
YK		 818/* Returns verdict for packet, or -1 for invalid. */
819static int tcp_packet(struct nf_conn *conntrack,
820 const struct sk_buff *skb,
821 unsigned int dataoff,
822 enum ip_conntrack_info ctinfo,
823 int pf,
824 unsigned int hooknum)
825{
826 enum tcp_conntrack new_state, old_state;
827 enum ip_conntrack_dir dir;
828 struct tcphdr *th, _tcph;
829 unsigned long timeout;
830 unsigned int index;
831
832 th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph);
833 BUG_ON(th == NULL);
834
835 write_lock_bh(&tcp_lock);
836 old_state = conntrack->proto.tcp.state;
837 dir = CTINFO2DIR(ctinfo);
838 index = get_conntrack_index(th);
839 new_state = tcp_conntracks[dir][index][old_state];
840
841 switch (new_state) {
842 case TCP_CONNTRACK_IGNORE:
73f30602
JK		 843 /* Ignored packets:
844 *
845 * a) SYN in ORIGINAL
846 * b) SYN/ACK in REPLY
601e68e1 847 * c) ACK in reply direction after initial SYN in original.
73f30602 848 */
9fb9cbb1
YK		 849 if (index == TCP_SYNACK_SET
850 && conntrack->proto.tcp.last_index == TCP_SYN_SET
851 && conntrack->proto.tcp.last_dir != dir
852 && ntohl(th->ack_seq) ==
601e68e1
YH		 853 conntrack->proto.tcp.last_end) {
854 /* This SYN/ACK acknowledges a SYN that we earlier
9fb9cbb1
YK		 855 * ignored as invalid. This means that the client and
856 * the server are both in sync, while the firewall is
857 * not. We kill this session and block the SYN/ACK so
601e68e1 858 * that the client cannot but retransmit its SYN and
9fb9cbb1
YK		 859 * thus initiate a clean new session.
860 */
601e68e1 861 write_unlock_bh(&tcp_lock);
9fb9cbb1
YK		 862 if (LOG_INVALID(IPPROTO_TCP))
863 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
864 "nf_ct_tcp: killing out of sync session ");
601e68e1
YH		 865 if (del_timer(&conntrack->timeout))
866 conntrack->timeout.function((unsigned long)
867 conntrack);
868 return -NF_DROP;
9fb9cbb1
YK		 869 }
870 conntrack->proto.tcp.last_index = index;
871 conntrack->proto.tcp.last_dir = dir;
872 conntrack->proto.tcp.last_seq = ntohl(th->seq);
873 conntrack->proto.tcp.last_end =
874 segment_seq_plus_len(ntohl(th->seq), skb->len, dataoff, th);
875
876 write_unlock_bh(&tcp_lock);
877 if (LOG_INVALID(IPPROTO_TCP))
878 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
879 "nf_ct_tcp: invalid packed ignored ");
880 return NF_ACCEPT;
881 case TCP_CONNTRACK_MAX:
882 /* Invalid packet */
883 DEBUGP("nf_ct_tcp: Invalid dir=%i index=%u ostate=%u\n",
884 dir, get_conntrack_index(th),
885 old_state);
886 write_unlock_bh(&tcp_lock);
887 if (LOG_INVALID(IPPROTO_TCP))
888 nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
889 "nf_ct_tcp: invalid state ");
890 return -NF_ACCEPT;
891 case TCP_CONNTRACK_SYN_SENT:
892 if (old_state < TCP_CONNTRACK_TIME_WAIT)
893 break;
894 if ((conntrack->proto.tcp.seen[dir].flags &
895 IP_CT_TCP_FLAG_CLOSE_INIT)
896 || after(ntohl(th->seq),
897 conntrack->proto.tcp.seen[dir].td_end)) {
601e68e1
YH		 898 /* Attempt to reopen a closed connection.
899 * Delete this connection and look up again. */
900 write_unlock_bh(&tcp_lock);
901 if (del_timer(&conntrack->timeout))
902 conntrack->timeout.function((unsigned long)
903 conntrack);
904 return -NF_REPEAT;
3746a2b1
KK		 905 } else {
906 write_unlock_bh(&tcp_lock);
907 if (LOG_INVALID(IPPROTO_TCP))
908 nf_log_packet(pf, 0, skb, NULL, NULL,
909 NULL, "nf_ct_tcp: invalid SYN");
910 return -NF_ACCEPT;
9fb9cbb1
YK		 911 }
912 case TCP_CONNTRACK_CLOSE:
913 if (index == TCP_RST_SET
73f30602 914 && ((test_bit(IPS_SEEN_REPLY_BIT, &conntrack->status)
601e68e1
YH		 915 && conntrack->proto.tcp.last_index == TCP_SYN_SET)
916 || (!test_bit(IPS_ASSURED_BIT, &conntrack->status)
917 && conntrack->proto.tcp.last_index == TCP_ACK_SET))
9fb9cbb1 918 && ntohl(th->ack_seq) == conntrack->proto.tcp.last_end) {
93b1fae4 919 /* RST sent to invalid SYN or ACK we had let through
73f30602
JK		 920 * at a) and c) above:
921 *
922 * a) SYN was in window then
923 * c) we hold a half-open connection.
924 *
925 * Delete our connection entry.
9fb9cbb1 926 * We skip window checking, because packet might ACK
73f30602 927 * segments we ignored. */
9fb9cbb1
YK		 928 goto in_window;
929 }
93b1fae4 930 /* Just fall through */
9fb9cbb1
YK		 931 default:
932 /* Keep compilers happy. */
933 break;
934 }
935
936 if (!tcp_in_window(&conntrack->proto.tcp, dir, index,
937 skb, dataoff, th, pf)) {
938 write_unlock_bh(&tcp_lock);
939 return -NF_ACCEPT;
940 }
941 in_window:
942 /* From now on we have got in-window packets */
943 conntrack->proto.tcp.last_index = index;
944
945 DEBUGP("tcp_conntracks: src=%u.%u.%u.%u:%hu dst=%u.%u.%u.%u:%hu "
946 "syn=%i ack=%i fin=%i rst=%i old=%i new=%i\n",
947 NIPQUAD(iph->saddr), ntohs(th->source),
948 NIPQUAD(iph->daddr), ntohs(th->dest),
949 (th->syn ? 1 : 0), (th->ack ? 1 : 0),
950 (th->fin ? 1 : 0), (th->rst ? 1 : 0),
951 old_state, new_state);
952
953 conntrack->proto.tcp.state = new_state;
954 if (old_state != new_state
955 && (new_state == TCP_CONNTRACK_FIN_WAIT
956 || new_state == TCP_CONNTRACK_CLOSE))
957 conntrack->proto.tcp.seen[dir].flags |= IP_CT_TCP_FLAG_CLOSE_INIT;
958 timeout = conntrack->proto.tcp.retrans >= nf_ct_tcp_max_retrans
959 && *tcp_timeouts[new_state] > nf_ct_tcp_timeout_max_retrans
960 ? nf_ct_tcp_timeout_max_retrans : *tcp_timeouts[new_state];
961 write_unlock_bh(&tcp_lock);
962
963 nf_conntrack_event_cache(IPCT_PROTOINFO_VOLATILE, skb);
964 if (new_state != old_state)
965 nf_conntrack_event_cache(IPCT_PROTOINFO, skb);
966
967 if (!test_bit(IPS_SEEN_REPLY_BIT, &conntrack->status)) {
968 /* If only reply is a RST, we can consider ourselves not to
969 have an established connection: this is a fairly common
970 problem case, so we can delete the conntrack
971 immediately. --RR */
972 if (th->rst) {
973 if (del_timer(&conntrack->timeout))
974 conntrack->timeout.function((unsigned long)
975 conntrack);
976 return NF_ACCEPT;
977 }
978 } else if (!test_bit(IPS_ASSURED_BIT, &conntrack->status)
979 && (old_state == TCP_CONNTRACK_SYN_RECV
980 || old_state == TCP_CONNTRACK_ESTABLISHED)
981 && new_state == TCP_CONNTRACK_ESTABLISHED) {
601e68e1
YH		 982 /* Set ASSURED if we see see valid ack in ESTABLISHED
983 after SYN_RECV or a valid answer for a picked up
9fb9cbb1
YK		 984 connection. */
985 set_bit(IPS_ASSURED_BIT, &conntrack->status);
986 nf_conntrack_event_cache(IPCT_STATUS, skb);
987 }
988 nf_ct_refresh_acct(conntrack, ctinfo, skb, timeout);
989
990 return NF_ACCEPT;
991}
601e68e1 992
9fb9cbb1
YK		 993/* Called when a new connection for this protocol found. */
994static int tcp_new(struct nf_conn *conntrack,
995 const struct sk_buff *skb,
996 unsigned int dataoff)
997{
998 enum tcp_conntrack new_state;
999 struct tcphdr *th, _tcph;
1000#ifdef DEBUGP_VARS
1001 struct ip_ct_tcp_state *sender = &conntrack->proto.tcp.seen[0];
1002 struct ip_ct_tcp_state *receiver = &conntrack->proto.tcp.seen[1];
1003#endif
1004
1005 th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph);
1006 BUG_ON(th == NULL);
1007
1008 /* Don't need lock here: this conntrack not in circulation yet */
1009 new_state
1010 = tcp_conntracks[0][get_conntrack_index(th)]
1011 [TCP_CONNTRACK_NONE];
1012
1013 /* Invalid: delete conntrack */
1014 if (new_state >= TCP_CONNTRACK_MAX) {
1015 DEBUGP("nf_ct_tcp: invalid new deleting.\n");
1016 return 0;
1017 }
1018
1019 if (new_state == TCP_CONNTRACK_SYN_SENT) {
1020 /* SYN packet */
1021 conntrack->proto.tcp.seen[0].td_end =
1022 segment_seq_plus_len(ntohl(th->seq), skb->len,
1023 dataoff, th);
1024 conntrack->proto.tcp.seen[0].td_maxwin = ntohs(th->window);
1025 if (conntrack->proto.tcp.seen[0].td_maxwin == 0)
1026 conntrack->proto.tcp.seen[0].td_maxwin = 1;
1027 conntrack->proto.tcp.seen[0].td_maxend =
1028 conntrack->proto.tcp.seen[0].td_end;
1029
1030 tcp_options(skb, dataoff, th, &conntrack->proto.tcp.seen[0]);
1031 conntrack->proto.tcp.seen[1].flags = 0;
9fb9cbb1
YK		 1032 } else if (nf_ct_tcp_loose == 0) {
1033 /* Don't try to pick up connections. */
1034 return 0;
1035 } else {
1036 /*
1037 * We are in the middle of a connection,
1038 * its history is lost for us.
1039 * Let's try to use the data from the packet.
1040 */
1041 conntrack->proto.tcp.seen[0].td_end =
1042 segment_seq_plus_len(ntohl(th->seq), skb->len,
1043 dataoff, th);
1044 conntrack->proto.tcp.seen[0].td_maxwin = ntohs(th->window);
1045 if (conntrack->proto.tcp.seen[0].td_maxwin == 0)
1046 conntrack->proto.tcp.seen[0].td_maxwin = 1;
1047 conntrack->proto.tcp.seen[0].td_maxend =
601e68e1 1048 conntrack->proto.tcp.seen[0].td_end +
9fb9cbb1
YK		 1049 conntrack->proto.tcp.seen[0].td_maxwin;
1050 conntrack->proto.tcp.seen[0].td_scale = 0;
1051
a09113c2
PM		 1052 /* We assume SACK and liberal window checking to handle
1053 * window scaling */
9fb9cbb1 1054 conntrack->proto.tcp.seen[0].flags =
a09113c2
PM		 1055 conntrack->proto.tcp.seen[1].flags = IP_CT_TCP_FLAG_SACK_PERM |
1056 IP_CT_TCP_FLAG_BE_LIBERAL;
9fb9cbb1 1057 }
601e68e1 1058
9fb9cbb1
YK		 1059 conntrack->proto.tcp.seen[1].td_end = 0;
1060 conntrack->proto.tcp.seen[1].td_maxend = 0;
1061 conntrack->proto.tcp.seen[1].td_maxwin = 1;
601e68e1 1062 conntrack->proto.tcp.seen[1].td_scale = 0;
9fb9cbb1
YK		 1063
1064 /* tcp_packet will set them */
1065 conntrack->proto.tcp.state = TCP_CONNTRACK_NONE;
1066 conntrack->proto.tcp.last_index = TCP_NONE_SET;
601e68e1 1067
9fb9cbb1
YK		 1068 DEBUGP("tcp_new: sender end=%u maxend=%u maxwin=%u scale=%i "
1069 "receiver end=%u maxend=%u maxwin=%u scale=%i\n",
1070 sender->td_end, sender->td_maxend, sender->td_maxwin,
601e68e1 1071 sender->td_scale,
9fb9cbb1
YK		 1072 receiver->td_end, receiver->td_maxend, receiver->td_maxwin,
1073 receiver->td_scale);
1074 return 1;
1075}
c1d10adb 1076
e281db5c 1077#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
c1d10adb
PNA		 1078
1079#include <linux/netfilter/nfnetlink.h>
1080#include <linux/netfilter/nfnetlink_conntrack.h>
1081
1082static int tcp_to_nfattr(struct sk_buff *skb, struct nfattr *nfa,
1083 const struct nf_conn *ct)
1084{
1085 struct nfattr *nest_parms;
c8e2078c 1086 struct nf_ct_tcp_flags tmp = {};
601e68e1 1087
c1d10adb
PNA		 1088 read_lock_bh(&tcp_lock);
1089 nest_parms = NFA_NEST(skb, CTA_PROTOINFO_TCP);
1090 NFA_PUT(skb, CTA_PROTOINFO_TCP_STATE, sizeof(u_int8_t),
1091 &ct->proto.tcp.state);
c8e2078c
PNA		 1092
1093 NFA_PUT(skb, CTA_PROTOINFO_TCP_WSCALE_ORIGINAL, sizeof(u_int8_t),
1094 &ct->proto.tcp.seen[0].td_scale);
1095
1096 NFA_PUT(skb, CTA_PROTOINFO_TCP_WSCALE_REPLY, sizeof(u_int8_t),
1097 &ct->proto.tcp.seen[1].td_scale);
1098
1099 tmp.flags = ct->proto.tcp.seen[0].flags;
1100 NFA_PUT(skb, CTA_PROTOINFO_TCP_FLAGS_ORIGINAL,
1101 sizeof(struct nf_ct_tcp_flags), &tmp);
1102
1103 tmp.flags = ct->proto.tcp.seen[1].flags;
1104 NFA_PUT(skb, CTA_PROTOINFO_TCP_FLAGS_REPLY,
1105 sizeof(struct nf_ct_tcp_flags), &tmp);
c1d10adb
PNA		 1106 read_unlock_bh(&tcp_lock);
1107
1108 NFA_NEST_END(skb, nest_parms);
1109
1110 return 0;
1111
1112nfattr_failure:
1113 read_unlock_bh(&tcp_lock);
1114 return -1;
1115}
1116
1117static const size_t cta_min_tcp[CTA_PROTOINFO_TCP_MAX] = {
c8e2078c
PNA		 1118 [CTA_PROTOINFO_TCP_STATE-1] = sizeof(u_int8_t),
1119 [CTA_PROTOINFO_TCP_WSCALE_ORIGINAL-1] = sizeof(u_int8_t),
1120 [CTA_PROTOINFO_TCP_WSCALE_REPLY-1] = sizeof(u_int8_t),
1121 [CTA_PROTOINFO_TCP_FLAGS_ORIGINAL-1] = sizeof(struct nf_ct_tcp_flags),
1122 [CTA_PROTOINFO_TCP_FLAGS_REPLY-1] = sizeof(struct nf_ct_tcp_flags)
c1d10adb
PNA		 1123};
1124
1125static int nfattr_to_tcp(struct nfattr *cda[], struct nf_conn *ct)
1126{
1127 struct nfattr *attr = cda[CTA_PROTOINFO_TCP-1];
1128 struct nfattr *tb[CTA_PROTOINFO_TCP_MAX];
1129
1130 /* updates could not contain anything about the private
1131 * protocol info, in that case skip the parsing */
1132 if (!attr)
1133 return 0;
1134
601e68e1 1135 nfattr_parse_nested(tb, CTA_PROTOINFO_TCP_MAX, attr);
c1d10adb
PNA		 1136
1137 if (nfattr_bad_size(tb, CTA_PROTOINFO_TCP_MAX, cta_min_tcp))
1138 return -EINVAL;
1139
1140 if (!tb[CTA_PROTOINFO_TCP_STATE-1])
1141 return -EINVAL;
1142
1143 write_lock_bh(&tcp_lock);
601e68e1 1144 ct->proto.tcp.state =
c1d10adb 1145 *(u_int8_t *)NFA_DATA(tb[CTA_PROTOINFO_TCP_STATE-1]);
c8e2078c
PNA		 1146
1147 if (tb[CTA_PROTOINFO_TCP_FLAGS_ORIGINAL-1]) {
1148 struct nf_ct_tcp_flags *attr =
1149 NFA_DATA(tb[CTA_PROTOINFO_TCP_FLAGS_ORIGINAL-1]);
1150 ct->proto.tcp.seen[0].flags &= ~attr->mask;
1151 ct->proto.tcp.seen[0].flags |= attr->flags & attr->mask;
1152 }
1153
1154 if (tb[CTA_PROTOINFO_TCP_FLAGS_REPLY-1]) {
1155 struct nf_ct_tcp_flags *attr =
1156 NFA_DATA(tb[CTA_PROTOINFO_TCP_FLAGS_REPLY-1]);
1157 ct->proto.tcp.seen[1].flags &= ~attr->mask;
1158 ct->proto.tcp.seen[1].flags |= attr->flags & attr->mask;
1159 }
1160
1161 if (tb[CTA_PROTOINFO_TCP_WSCALE_ORIGINAL-1] &&
1162 tb[CTA_PROTOINFO_TCP_WSCALE_REPLY-1] &&
1163 ct->proto.tcp.seen[0].flags & IP_CT_TCP_FLAG_WINDOW_SCALE &&
1164 ct->proto.tcp.seen[1].flags & IP_CT_TCP_FLAG_WINDOW_SCALE) {
1165 ct->proto.tcp.seen[0].td_scale = *(u_int8_t *)
1166 NFA_DATA(tb[CTA_PROTOINFO_TCP_WSCALE_ORIGINAL-1]);
1167 ct->proto.tcp.seen[1].td_scale = *(u_int8_t *)
1168 NFA_DATA(tb[CTA_PROTOINFO_TCP_WSCALE_REPLY-1]);
1169 }
c1d10adb
PNA		 1170 write_unlock_bh(&tcp_lock);
1171
1172 return 0;
1173}
1174#endif
933a41e7
PM		 1175
1176#ifdef CONFIG_SYSCTL
1177static unsigned int tcp_sysctl_table_users;
1178static struct ctl_table_header *tcp_sysctl_header;
1179static struct ctl_table tcp_sysctl_table[] = {
1180 {
1181 .ctl_name = NET_NF_CONNTRACK_TCP_TIMEOUT_SYN_SENT,
1182 .procname = "nf_conntrack_tcp_timeout_syn_sent",
1183 .data = &nf_ct_tcp_timeout_syn_sent,
1184 .maxlen = sizeof(unsigned int),
1185 .mode = 0644,
1186 .proc_handler = &proc_dointvec_jiffies,
1187 },
1188 {
1189 .ctl_name = NET_NF_CONNTRACK_TCP_TIMEOUT_SYN_RECV,
1190 .procname = "nf_conntrack_tcp_timeout_syn_recv",
1191 .data = &nf_ct_tcp_timeout_syn_recv,
1192 .maxlen = sizeof(unsigned int),
1193 .mode = 0644,
1194 .proc_handler = &proc_dointvec_jiffies,
1195 },
1196 {
1197 .ctl_name = NET_NF_CONNTRACK_TCP_TIMEOUT_ESTABLISHED,
1198 .procname = "nf_conntrack_tcp_timeout_established",
1199 .data = &nf_ct_tcp_timeout_established,
1200 .maxlen = sizeof(unsigned int),
1201 .mode = 0644,
1202 .proc_handler = &proc_dointvec_jiffies,
1203 },
1204 {
1205 .ctl_name = NET_NF_CONNTRACK_TCP_TIMEOUT_FIN_WAIT,
1206 .procname = "nf_conntrack_tcp_timeout_fin_wait",
1207 .data = &nf_ct_tcp_timeout_fin_wait,
1208 .maxlen = sizeof(unsigned int),
1209 .mode = 0644,
1210 .proc_handler = &proc_dointvec_jiffies,
1211 },
1212 {
1213 .ctl_name = NET_NF_CONNTRACK_TCP_TIMEOUT_CLOSE_WAIT,
1214 .procname = "nf_conntrack_tcp_timeout_close_wait",
1215 .data = &nf_ct_tcp_timeout_close_wait,
1216 .maxlen = sizeof(unsigned int),
1217 .mode = 0644,
1218 .proc_handler = &proc_dointvec_jiffies,
1219 },
1220 {
1221 .ctl_name = NET_NF_CONNTRACK_TCP_TIMEOUT_LAST_ACK,
1222 .procname = "nf_conntrack_tcp_timeout_last_ack",
1223 .data = &nf_ct_tcp_timeout_last_ack,
1224 .maxlen = sizeof(unsigned int),
1225 .mode = 0644,
1226 .proc_handler = &proc_dointvec_jiffies,
1227 },
1228 {
1229 .ctl_name = NET_NF_CONNTRACK_TCP_TIMEOUT_TIME_WAIT,
1230 .procname = "nf_conntrack_tcp_timeout_time_wait",
1231 .data = &nf_ct_tcp_timeout_time_wait,
1232 .maxlen = sizeof(unsigned int),
1233 .mode = 0644,
1234 .proc_handler = &proc_dointvec_jiffies,
1235 },
1236 {
1237 .ctl_name = NET_NF_CONNTRACK_TCP_TIMEOUT_CLOSE,
1238 .procname = "nf_conntrack_tcp_timeout_close",
1239 .data = &nf_ct_tcp_timeout_close,
1240 .maxlen = sizeof(unsigned int),
1241 .mode = 0644,
1242 .proc_handler = &proc_dointvec_jiffies,
1243 },
1244 {
1245 .ctl_name = NET_NF_CONNTRACK_TCP_TIMEOUT_MAX_RETRANS,
1246 .procname = "nf_conntrack_tcp_timeout_max_retrans",
1247 .data = &nf_ct_tcp_timeout_max_retrans,
1248 .maxlen = sizeof(unsigned int),
1249 .mode = 0644,
1250 .proc_handler = &proc_dointvec_jiffies,
1251 },
1252 {
1253 .ctl_name = NET_NF_CONNTRACK_TCP_LOOSE,
1254 .procname = "nf_conntrack_tcp_loose",
1255 .data = &nf_ct_tcp_loose,
1256 .maxlen = sizeof(unsigned int),
1257 .mode = 0644,
1258 .proc_handler = &proc_dointvec,
1259 },
1260 {
1261 .ctl_name = NET_NF_CONNTRACK_TCP_BE_LIBERAL,
1262 .procname = "nf_conntrack_tcp_be_liberal",
1263 .data = &nf_ct_tcp_be_liberal,
1264 .maxlen = sizeof(unsigned int),
1265 .mode = 0644,
1266 .proc_handler = &proc_dointvec,
1267 },
1268 {
1269 .ctl_name = NET_NF_CONNTRACK_TCP_MAX_RETRANS,
1270 .procname = "nf_conntrack_tcp_max_retrans",
1271 .data = &nf_ct_tcp_max_retrans,
1272 .maxlen = sizeof(unsigned int),
1273 .mode = 0644,
1274 .proc_handler = &proc_dointvec,
1275 },
1276 {
1277 .ctl_name = 0
1278 }
1279};
a999e683
PM		 1280
1281#ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
1282static struct ctl_table tcp_compat_sysctl_table[] = {
1283 {
1284 .ctl_name = NET_IPV4_NF_CONNTRACK_TCP_TIMEOUT_SYN_SENT,
1285 .procname = "ip_conntrack_tcp_timeout_syn_sent",
1286 .data = &nf_ct_tcp_timeout_syn_sent,
1287 .maxlen = sizeof(unsigned int),
1288 .mode = 0644,
1289 .proc_handler = &proc_dointvec_jiffies,
1290 },
1291 {
1292 .ctl_name = NET_IPV4_NF_CONNTRACK_TCP_TIMEOUT_SYN_RECV,
1293 .procname = "ip_conntrack_tcp_timeout_syn_recv",
1294 .data = &nf_ct_tcp_timeout_syn_recv,
1295 .maxlen = sizeof(unsigned int),
1296 .mode = 0644,
1297 .proc_handler = &proc_dointvec_jiffies,
1298 },
1299 {
1300 .ctl_name = NET_IPV4_NF_CONNTRACK_TCP_TIMEOUT_ESTABLISHED,
1301 .procname = "ip_conntrack_tcp_timeout_established",
1302 .data = &nf_ct_tcp_timeout_established,
1303 .maxlen = sizeof(unsigned int),
1304 .mode = 0644,
1305 .proc_handler = &proc_dointvec_jiffies,
1306 },
1307 {
1308 .ctl_name = NET_IPV4_NF_CONNTRACK_TCP_TIMEOUT_FIN_WAIT,
1309 .procname = "ip_conntrack_tcp_timeout_fin_wait",
1310 .data = &nf_ct_tcp_timeout_fin_wait,
1311 .maxlen = sizeof(unsigned int),
1312 .mode = 0644,
1313 .proc_handler = &proc_dointvec_jiffies,
1314 },
1315 {
1316 .ctl_name = NET_IPV4_NF_CONNTRACK_TCP_TIMEOUT_CLOSE_WAIT,
1317 .procname = "ip_conntrack_tcp_timeout_close_wait",
1318 .data = &nf_ct_tcp_timeout_close_wait,
1319 .maxlen = sizeof(unsigned int),
1320 .mode = 0644,
1321 .proc_handler = &proc_dointvec_jiffies,
1322 },
1323 {
1324 .ctl_name = NET_IPV4_NF_CONNTRACK_TCP_TIMEOUT_LAST_ACK,
1325 .procname = "ip_conntrack_tcp_timeout_last_ack",
1326 .data = &nf_ct_tcp_timeout_last_ack,
1327 .maxlen = sizeof(unsigned int),
1328 .mode = 0644,
1329 .proc_handler = &proc_dointvec_jiffies,
1330 },
1331 {
1332 .ctl_name = NET_IPV4_NF_CONNTRACK_TCP_TIMEOUT_TIME_WAIT,
1333 .procname = "ip_conntrack_tcp_timeout_time_wait",
1334 .data = &nf_ct_tcp_timeout_time_wait,
1335 .maxlen = sizeof(unsigned int),
1336 .mode = 0644,
1337 .proc_handler = &proc_dointvec_jiffies,
1338 },
1339 {
1340 .ctl_name = NET_IPV4_NF_CONNTRACK_TCP_TIMEOUT_CLOSE,
1341 .procname = "ip_conntrack_tcp_timeout_close",
1342 .data = &nf_ct_tcp_timeout_close,
1343 .maxlen = sizeof(unsigned int),
1344 .mode = 0644,
1345 .proc_handler = &proc_dointvec_jiffies,
1346 },
1347 {
1348 .ctl_name = NET_IPV4_NF_CONNTRACK_TCP_TIMEOUT_MAX_RETRANS,
1349 .procname = "ip_conntrack_tcp_timeout_max_retrans",
1350 .data = &nf_ct_tcp_timeout_max_retrans,
1351 .maxlen = sizeof(unsigned int),
1352 .mode = 0644,
1353 .proc_handler = &proc_dointvec_jiffies,
1354 },
1355 {
1356 .ctl_name = NET_IPV4_NF_CONNTRACK_TCP_LOOSE,
1357 .procname = "ip_conntrack_tcp_loose",
1358 .data = &nf_ct_tcp_loose,
1359 .maxlen = sizeof(unsigned int),
1360 .mode = 0644,
1361 .proc_handler = &proc_dointvec,
1362 },
1363 {
1364 .ctl_name = NET_IPV4_NF_CONNTRACK_TCP_BE_LIBERAL,
1365 .procname = "ip_conntrack_tcp_be_liberal",
1366 .data = &nf_ct_tcp_be_liberal,
1367 .maxlen = sizeof(unsigned int),
1368 .mode = 0644,
1369 .proc_handler = &proc_dointvec,
1370 },
1371 {
1372 .ctl_name = NET_IPV4_NF_CONNTRACK_TCP_MAX_RETRANS,
1373 .procname = "ip_conntrack_tcp_max_retrans",
1374 .data = &nf_ct_tcp_max_retrans,
1375 .maxlen = sizeof(unsigned int),
1376 .mode = 0644,
1377 .proc_handler = &proc_dointvec,
1378 },
1379 {
1380 .ctl_name = 0
1381 }
1382};
1383#endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
933a41e7
PM		 1384#endif /* CONFIG_SYSCTL */
1385
605dcad6 1386struct nf_conntrack_l4proto nf_conntrack_l4proto_tcp4 =
9fb9cbb1
YK		 1387{
1388 .l3proto = PF_INET,
605dcad6 1389 .l4proto = IPPROTO_TCP,
9fb9cbb1
YK		 1390 .name = "tcp",
1391 .pkt_to_tuple = tcp_pkt_to_tuple,
1392 .invert_tuple = tcp_invert_tuple,
1393 .print_tuple = tcp_print_tuple,
1394 .print_conntrack = tcp_print_conntrack,
1395 .packet = tcp_packet,
1396 .new = tcp_new,
96f6bf82 1397 .error = tcp_error,
e281db5c 1398#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
c1d10adb
PNA		 1399 .to_nfattr = tcp_to_nfattr,
1400 .from_nfattr = nfattr_to_tcp,
1401 .tuple_to_nfattr = nf_ct_port_tuple_to_nfattr,
1402 .nfattr_to_tuple = nf_ct_port_nfattr_to_tuple,
1403#endif
933a41e7
PM		 1404#ifdef CONFIG_SYSCTL
1405 .ctl_table_users = &tcp_sysctl_table_users,
1406 .ctl_table_header = &tcp_sysctl_header,
1407 .ctl_table = tcp_sysctl_table,
a999e683
PM		 1408#ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
1409 .ctl_compat_table = tcp_compat_sysctl_table,
1410#endif
933a41e7 1411#endif
9fb9cbb1 1412};
13b18339 1413EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_tcp4);
9fb9cbb1 1414
605dcad6 1415struct nf_conntrack_l4proto nf_conntrack_l4proto_tcp6 =
9fb9cbb1
YK		 1416{
1417 .l3proto = PF_INET6,
605dcad6 1418 .l4proto = IPPROTO_TCP,
9fb9cbb1
YK		 1419 .name = "tcp",
1420 .pkt_to_tuple = tcp_pkt_to_tuple,
1421 .invert_tuple = tcp_invert_tuple,
1422 .print_tuple = tcp_print_tuple,
1423 .print_conntrack = tcp_print_conntrack,
1424 .packet = tcp_packet,
1425 .new = tcp_new,
96f6bf82 1426 .error = tcp_error,
e281db5c 1427#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
c1d10adb
PNA		 1428 .to_nfattr = tcp_to_nfattr,
1429 .from_nfattr = nfattr_to_tcp,
1430 .tuple_to_nfattr = nf_ct_port_tuple_to_nfattr,
1431 .nfattr_to_tuple = nf_ct_port_nfattr_to_tuple,
1432#endif
933a41e7
PM		 1433#ifdef CONFIG_SYSCTL
1434 .ctl_table_users = &tcp_sysctl_table_users,
1435 .ctl_table_header = &tcp_sysctl_header,
1436 .ctl_table = tcp_sysctl_table,
1437#endif
9fb9cbb1 1438};
13b18339 1439EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_tcp6);
kernel source for telekom puls (alcatel/mediatek)