1// SPDX-License-Identifier: GPL-2.0-only 2/* (C) 1999-2001 Paul `Rusty' Russell 3 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> 4 * (C) 2002-2013 Jozsef Kadlecsik <kadlec@netfilter.org> 5 * (C) 2006-2012 Patrick McHardy <kaber@trash.net> 6 */ 7 8#include <linux/types.h> 9#include <linux/timer.h> 10#include <linux/module.h> 11#include <linux/in.h> 12#include <linux/tcp.h> 13#include <linux/spinlock.h> 14#include <linux/skbuff.h> 15#include <linux/ipv6.h> 16#include <net/ip6_checksum.h> 17#include <asm/unaligned.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#include <net/netfilter/nf_conntrack_seqadj.h> 28#include <net/netfilter/nf_conntrack_synproxy.h> 29#include <net/netfilter/nf_conntrack_timeout.h> 30#include <net/netfilter/nf_log.h> 31#include <net/netfilter/ipv4/nf_conntrack_ipv4.h> 32#include <net/netfilter/ipv6/nf_conntrack_ipv6.h> 33 34 /* FIXME: Examine ipfilter's timeouts and conntrack transitions more 35 closely. They're more complex. --RR */ 36 37static const char *const tcp_conntrack_names[] = { 38 "NONE", 39 "SYN_SENT", 40 "SYN_RECV", 41 "ESTABLISHED", 42 "FIN_WAIT", 43 "CLOSE_WAIT", 44 "LAST_ACK", 45 "TIME_WAIT", 46 "CLOSE", 47 "SYN_SENT2", 48}; 49 50enum nf_ct_tcp_action { 51 NFCT_TCP_IGNORE, 52 NFCT_TCP_INVALID, 53 NFCT_TCP_ACCEPT, 54}; 55 56#define SECS * HZ 57#define MINS * 60 SECS 58#define HOURS * 60 MINS 59#define DAYS * 24 HOURS 60 61static const unsigned int tcp_timeouts[TCP_CONNTRACK_TIMEOUT_MAX] = { 62 [TCP_CONNTRACK_SYN_SENT] = 2 MINS, 63 [TCP_CONNTRACK_SYN_RECV] = 60 SECS, 64 [TCP_CONNTRACK_ESTABLISHED] = 5 DAYS, 65 [TCP_CONNTRACK_FIN_WAIT] = 2 MINS, 66 [TCP_CONNTRACK_CLOSE_WAIT] = 60 SECS, 67 [TCP_CONNTRACK_LAST_ACK] = 30 SECS, 68 [TCP_CONNTRACK_TIME_WAIT] = 2 MINS, 69 [TCP_CONNTRACK_CLOSE] = 10 SECS, 70 [TCP_CONNTRACK_SYN_SENT2] = 2 MINS, 71/* RFC1122 says the R2 limit should be at least 100 seconds. 72 Linux uses 15 packets as limit, which corresponds 73 to ~13-30min depending on RTO. */ 74 [TCP_CONNTRACK_RETRANS] = 5 MINS, 75 [TCP_CONNTRACK_UNACK] = 5 MINS, 76}; 77 78#define sNO TCP_CONNTRACK_NONE 79#define sSS TCP_CONNTRACK_SYN_SENT 80#define sSR TCP_CONNTRACK_SYN_RECV 81#define sES TCP_CONNTRACK_ESTABLISHED 82#define sFW TCP_CONNTRACK_FIN_WAIT 83#define sCW TCP_CONNTRACK_CLOSE_WAIT 84#define sLA TCP_CONNTRACK_LAST_ACK 85#define sTW TCP_CONNTRACK_TIME_WAIT 86#define sCL TCP_CONNTRACK_CLOSE 87#define sS2 TCP_CONNTRACK_SYN_SENT2 88#define sIV TCP_CONNTRACK_MAX 89#define sIG TCP_CONNTRACK_IGNORE 90 91/* What TCP flags are set from RST/SYN/FIN/ACK. */ 92enum tcp_bit_set { 93 TCP_SYN_SET, 94 TCP_SYNACK_SET, 95 TCP_FIN_SET, 96 TCP_ACK_SET, 97 TCP_RST_SET, 98 TCP_NONE_SET, 99}; 100 101/* 102 * The TCP state transition table needs a few words... 103 * 104 * We are the man in the middle. All the packets go through us 105 * but might get lost in transit to the destination. 106 * It is assumed that the destinations can't receive segments 107 * we haven't seen. 108 * 109 * The checked segment is in window, but our windows are *not* 110 * equivalent with the ones of the sender/receiver. We always 111 * try to guess the state of the current sender. 112 * 113 * The meaning of the states are: 114 * 115 * NONE: initial state 116 * SYN_SENT: SYN-only packet seen 117 * SYN_SENT2: SYN-only packet seen from reply dir, simultaneous open 118 * SYN_RECV: SYN-ACK packet seen 119 * ESTABLISHED: ACK packet seen 120 * FIN_WAIT: FIN packet seen 121 * CLOSE_WAIT: ACK seen (after FIN) 122 * LAST_ACK: FIN seen (after FIN) 123 * TIME_WAIT: last ACK seen 124 * CLOSE: closed connection (RST) 125 * 126 * Packets marked as IGNORED (sIG): 127 * if they may be either invalid or valid 128 * and the receiver may send back a connection 129 * closing RST or a SYN/ACK. 130 * 131 * Packets marked as INVALID (sIV): 132 * if we regard them as truly invalid packets 133 */ 134static const u8 tcp_conntracks[2][6][TCP_CONNTRACK_MAX] = { 135 { 136/* ORIGINAL */ 137/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ 138/*syn*/ { sSS, sSS, sIG, sIG, sIG, sIG, sIG, sSS, sSS, sS2 }, 139/* 140 * sNO -> sSS Initialize a new connection 141 * sSS -> sSS Retransmitted SYN 142 * sS2 -> sS2 Late retransmitted SYN 143 * sSR -> sIG 144 * sES -> sIG Error: SYNs in window outside the SYN_SENT state 145 * are errors. Receiver will reply with RST 146 * and close the connection. 147 * Or we are not in sync and hold a dead connection. 148 * sFW -> sIG 149 * sCW -> sIG 150 * sLA -> sIG 151 * sTW -> sSS Reopened connection (RFC 1122). 152 * sCL -> sSS 153 */ 154/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ 155/*synack*/ { sIV, sIV, sSR, sIV, sIV, sIV, sIV, sIV, sIV, sSR }, 156/* 157 * sNO -> sIV Too late and no reason to do anything 158 * sSS -> sIV Client can't send SYN and then SYN/ACK 159 * sS2 -> sSR SYN/ACK sent to SYN2 in simultaneous open 160 * sSR -> sSR Late retransmitted SYN/ACK in simultaneous open 161 * sES -> sIV Invalid SYN/ACK packets sent by the client 162 * sFW -> sIV 163 * sCW -> sIV 164 * sLA -> sIV 165 * sTW -> sIV 166 * sCL -> sIV 167 */ 168/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ 169/*fin*/ { sIV, sIV, sFW, sFW, sLA, sLA, sLA, sTW, sCL, sIV }, 170/* 171 * sNO -> sIV Too late and no reason to do anything... 172 * sSS -> sIV Client migth not send FIN in this state: 173 * we enforce waiting for a SYN/ACK reply first. 174 * sS2 -> sIV 175 * sSR -> sFW Close started. 176 * sES -> sFW 177 * sFW -> sLA FIN seen in both directions, waiting for 178 * the last ACK. 179 * Migth be a retransmitted FIN as well... 180 * sCW -> sLA 181 * sLA -> sLA Retransmitted FIN. Remain in the same state. 182 * sTW -> sTW 183 * sCL -> sCL 184 */ 185/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ 186/*ack*/ { sES, sIV, sES, sES, sCW, sCW, sTW, sTW, sCL, sIV }, 187/* 188 * sNO -> sES Assumed. 189 * sSS -> sIV ACK is invalid: we haven't seen a SYN/ACK yet. 190 * sS2 -> sIV 191 * sSR -> sES Established state is reached. 192 * sES -> sES :-) 193 * sFW -> sCW Normal close request answered by ACK. 194 * sCW -> sCW 195 * sLA -> sTW Last ACK detected (RFC5961 challenged) 196 * sTW -> sTW Retransmitted last ACK. Remain in the same state. 197 * sCL -> sCL 198 */ 199/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ 200/*rst*/ { sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL }, 201/*none*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV } 202 }, 203 { 204/* REPLY */ 205/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ 206/*syn*/ { sIV, sS2, sIV, sIV, sIV, sIV, sIV, sSS, sIV, sS2 }, 207/* 208 * sNO -> sIV Never reached. 209 * sSS -> sS2 Simultaneous open 210 * sS2 -> sS2 Retransmitted simultaneous SYN 211 * sSR -> sIV Invalid SYN packets sent by the server 212 * sES -> sIV 213 * sFW -> sIV 214 * sCW -> sIV 215 * sLA -> sIV 216 * sTW -> sSS Reopened connection, but server may have switched role 217 * sCL -> sIV 218 */ 219/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ 220/*synack*/ { sIV, sSR, sIG, sIG, sIG, sIG, sIG, sIG, sIG, sSR }, 221/* 222 * sSS -> sSR Standard open. 223 * sS2 -> sSR Simultaneous open 224 * sSR -> sIG Retransmitted SYN/ACK, ignore it. 225 * sES -> sIG Late retransmitted SYN/ACK? 226 * sFW -> sIG Might be SYN/ACK answering ignored SYN 227 * sCW -> sIG 228 * sLA -> sIG 229 * sTW -> sIG 230 * sCL -> sIG 231 */ 232/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ 233/*fin*/ { sIV, sIV, sFW, sFW, sLA, sLA, sLA, sTW, sCL, sIV }, 234/* 235 * sSS -> sIV Server might not send FIN in this state. 236 * sS2 -> sIV 237 * sSR -> sFW Close started. 238 * sES -> sFW 239 * sFW -> sLA FIN seen in both directions. 240 * sCW -> sLA 241 * sLA -> sLA Retransmitted FIN. 242 * sTW -> sTW 243 * sCL -> sCL 244 */ 245/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ 246/*ack*/ { sIV, sIG, sSR, sES, sCW, sCW, sTW, sTW, sCL, sIG }, 247/* 248 * sSS -> sIG Might be a half-open connection. 249 * sS2 -> sIG 250 * sSR -> sSR Might answer late resent SYN. 251 * sES -> sES :-) 252 * sFW -> sCW Normal close request answered by ACK. 253 * sCW -> sCW 254 * sLA -> sTW Last ACK detected (RFC5961 challenged) 255 * sTW -> sTW Retransmitted last ACK. 256 * sCL -> sCL 257 */ 258/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ 259/*rst*/ { sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL }, 260/*none*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV } 261 } 262}; 263 264#ifdef CONFIG_NF_CONNTRACK_PROCFS 265/* Print out the private part of the conntrack. */ 266static void tcp_print_conntrack(struct seq_file *s, struct nf_conn *ct) 267{ 268 if (test_bit(IPS_OFFLOAD_BIT, &ct->status)) 269 return; 270 271 seq_printf(s, "%s ", tcp_conntrack_names[ct->proto.tcp.state]); 272} 273#endif 274 275static unsigned int get_conntrack_index(const struct tcphdr *tcph) 276{ 277 if (tcph->rst) return TCP_RST_SET; 278 else if (tcph->syn) return (tcph->ack ? TCP_SYNACK_SET : TCP_SYN_SET); 279 else if (tcph->fin) return TCP_FIN_SET; 280 else if (tcph->ack) return TCP_ACK_SET; 281 else return TCP_NONE_SET; 282} 283 284/* TCP connection tracking based on 'Real Stateful TCP Packet Filtering 285 in IP Filter' by Guido van Rooij. 286 287 http://www.sane.nl/events/sane2000/papers.html 288 http://www.darkart.com/mirrors/www.obfuscation.org/ipf/ 289 290 The boundaries and the conditions are changed according to RFC793: 291 the packet must intersect the window (i.e. segments may be 292 after the right or before the left edge) and thus receivers may ACK 293 segments after the right edge of the window. 294 295 td_maxend = max(sack + max(win,1)) seen in reply packets 296 td_maxwin = max(max(win, 1)) + (sack - ack) seen in sent packets 297 td_maxwin += seq + len - sender.td_maxend 298 if seq + len > sender.td_maxend 299 td_end = max(seq + len) seen in sent packets 300 301 I. Upper bound for valid data: seq <= sender.td_maxend 302 II. Lower bound for valid data: seq + len >= sender.td_end - receiver.td_maxwin 303 III. Upper bound for valid (s)ack: sack <= receiver.td_end 304 IV. Lower bound for valid (s)ack: sack >= receiver.td_end - MAXACKWINDOW 305 306 where sack is the highest right edge of sack block found in the packet 307 or ack in the case of packet without SACK option. 308 309 The upper bound limit for a valid (s)ack is not ignored - 310 we doesn't have to deal with fragments. 311*/ 312 313static inline __u32 segment_seq_plus_len(__u32 seq, 314 size_t len, 315 unsigned int dataoff, 316 const struct tcphdr *tcph) 317{ 318 /* XXX Should I use payload length field in IP/IPv6 header ? 319 * - YK */ 320 return (seq + len - dataoff - tcph->doff*4 321 + (tcph->syn ? 1 : 0) + (tcph->fin ? 1 : 0)); 322} 323 324/* Fixme: what about big packets? */ 325#define MAXACKWINCONST 66000 326#define MAXACKWINDOW(sender) \ 327 ((sender)->td_maxwin > MAXACKWINCONST ? (sender)->td_maxwin \ 328 : MAXACKWINCONST) 329 330/* 331 * Simplified tcp_parse_options routine from tcp_input.c 332 */ 333static void tcp_options(const struct sk_buff *skb, 334 unsigned int dataoff, 335 const struct tcphdr *tcph, 336 struct ip_ct_tcp_state *state) 337{ 338 unsigned char buff[(15 * 4) - sizeof(struct tcphdr)]; 339 const unsigned char *ptr; 340 int length = (tcph->doff*4) - sizeof(struct tcphdr); 341 342 if (!length) 343 return; 344 345 ptr = skb_header_pointer(skb, dataoff + sizeof(struct tcphdr), 346 length, buff); 347 if (!ptr) 348 return; 349 350 state->td_scale = 0; 351 state->flags &= IP_CT_TCP_FLAG_BE_LIBERAL; 352 353 while (length > 0) { 354 int opcode=*ptr++; 355 int opsize; 356 357 switch (opcode) { 358 case TCPOPT_EOL: 359 return; 360 case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */ 361 length--; 362 continue; 363 default: 364 if (length < 2) 365 return; 366 opsize=*ptr++; 367 if (opsize < 2) /* "silly options" */ 368 return; 369 if (opsize > length) 370 return; /* don't parse partial options */ 371 372 if (opcode == TCPOPT_SACK_PERM 373 && opsize == TCPOLEN_SACK_PERM) 374 state->flags |= IP_CT_TCP_FLAG_SACK_PERM; 375 else if (opcode == TCPOPT_WINDOW 376 && opsize == TCPOLEN_WINDOW) { 377 state->td_scale = *(u_int8_t *)ptr; 378 379 if (state->td_scale > TCP_MAX_WSCALE) 380 state->td_scale = TCP_MAX_WSCALE; 381 382 state->flags |= 383 IP_CT_TCP_FLAG_WINDOW_SCALE; 384 } 385 ptr += opsize - 2; 386 length -= opsize; 387 } 388 } 389} 390 391static void tcp_sack(const struct sk_buff *skb, unsigned int dataoff, 392 const struct tcphdr *tcph, __u32 *sack) 393{ 394 unsigned char buff[(15 * 4) - sizeof(struct tcphdr)]; 395 const unsigned char *ptr; 396 int length = (tcph->doff*4) - sizeof(struct tcphdr); 397 __u32 tmp; 398 399 if (!length) 400 return; 401 402 ptr = skb_header_pointer(skb, dataoff + sizeof(struct tcphdr), 403 length, buff); 404 if (!ptr) 405 return; 406 407 /* Fast path for timestamp-only option */ 408 if (length == TCPOLEN_TSTAMP_ALIGNED 409 && *(__be32 *)ptr == htonl((TCPOPT_NOP << 24) 410 | (TCPOPT_NOP << 16) 411 | (TCPOPT_TIMESTAMP << 8) 412 | TCPOLEN_TIMESTAMP)) 413 return; 414 415 while (length > 0) { 416 int opcode = *ptr++; 417 int opsize, i; 418 419 switch (opcode) { 420 case TCPOPT_EOL: 421 return; 422 case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */ 423 length--; 424 continue; 425 default: 426 if (length < 2) 427 return; 428 opsize = *ptr++; 429 if (opsize < 2) /* "silly options" */ 430 return; 431 if (opsize > length) 432 return; /* don't parse partial options */ 433 434 if (opcode == TCPOPT_SACK 435 && opsize >= (TCPOLEN_SACK_BASE 436 + TCPOLEN_SACK_PERBLOCK) 437 && !((opsize - TCPOLEN_SACK_BASE) 438 % TCPOLEN_SACK_PERBLOCK)) { 439 for (i = 0; 440 i < (opsize - TCPOLEN_SACK_BASE); 441 i += TCPOLEN_SACK_PERBLOCK) { 442 tmp = get_unaligned_be32((__be32 *)(ptr+i)+1); 443 444 if (after(tmp, *sack)) 445 *sack = tmp; 446 } 447 return; 448 } 449 ptr += opsize - 2; 450 length -= opsize; 451 } 452 } 453} 454 455static void tcp_init_sender(struct ip_ct_tcp_state *sender, 456 struct ip_ct_tcp_state *receiver, 457 const struct sk_buff *skb, 458 unsigned int dataoff, 459 const struct tcphdr *tcph, 460 u32 end, u32 win, 461 enum ip_conntrack_dir dir) 462{ 463 /* SYN-ACK in reply to a SYN 464 * or SYN from reply direction in simultaneous open. 465 */ 466 sender->td_end = 467 sender->td_maxend = end; 468 sender->td_maxwin = (win == 0 ? 1 : win); 469 470 tcp_options(skb, dataoff, tcph, sender); 471 /* RFC 1323: 472 * Both sides must send the Window Scale option 473 * to enable window scaling in either direction. 474 */ 475 if (dir == IP_CT_DIR_REPLY && 476 !(sender->flags & IP_CT_TCP_FLAG_WINDOW_SCALE && 477 receiver->flags & IP_CT_TCP_FLAG_WINDOW_SCALE)) { 478 sender->td_scale = 0; 479 receiver->td_scale = 0; 480 } 481} 482 483__printf(6, 7) 484static enum nf_ct_tcp_action nf_tcp_log_invalid(const struct sk_buff *skb, 485 const struct nf_conn *ct, 486 const struct nf_hook_state *state, 487 const struct ip_ct_tcp_state *sender, 488 enum nf_ct_tcp_action ret, 489 const char *fmt, ...) 490{ 491 const struct nf_tcp_net *tn = nf_tcp_pernet(nf_ct_net(ct)); 492 struct va_format vaf; 493 va_list args; 494 bool be_liberal; 495 496 be_liberal = sender->flags & IP_CT_TCP_FLAG_BE_LIBERAL || tn->tcp_be_liberal; 497 if (be_liberal) 498 return NFCT_TCP_ACCEPT; 499 500 va_start(args, fmt); 501 vaf.fmt = fmt; 502 vaf.va = &args; 503 nf_ct_l4proto_log_invalid(skb, ct, state, "%pV", &vaf); 504 va_end(args); 505 506 return ret; 507} 508 509static enum nf_ct_tcp_action 510tcp_in_window(struct nf_conn *ct, enum ip_conntrack_dir dir, 511 unsigned int index, const struct sk_buff *skb, 512 unsigned int dataoff, const struct tcphdr *tcph, 513 const struct nf_hook_state *hook_state) 514{ 515 struct ip_ct_tcp *state = &ct->proto.tcp; 516 struct ip_ct_tcp_state *sender = &state->seen[dir]; 517 struct ip_ct_tcp_state *receiver = &state->seen[!dir]; 518 __u32 seq, ack, sack, end, win, swin; 519 bool in_recv_win, seq_ok; 520 s32 receiver_offset; 521 u16 win_raw; 522 523 /* 524 * Get the required data from the packet. 525 */ 526 seq = ntohl(tcph->seq); 527 ack = sack = ntohl(tcph->ack_seq); 528 win_raw = ntohs(tcph->window); 529 win = win_raw; 530 end = segment_seq_plus_len(seq, skb->len, dataoff, tcph); 531 532 if (receiver->flags & IP_CT_TCP_FLAG_SACK_PERM) 533 tcp_sack(skb, dataoff, tcph, &sack); 534 535 /* Take into account NAT sequence number mangling */ 536 receiver_offset = nf_ct_seq_offset(ct, !dir, ack - 1); 537 ack -= receiver_offset; 538 sack -= receiver_offset; 539 540 if (sender->td_maxwin == 0) { 541 /* 542 * Initialize sender data. 543 */ 544 if (tcph->syn) { 545 tcp_init_sender(sender, receiver, 546 skb, dataoff, tcph, 547 end, win, dir); 548 if (!tcph->ack) 549 /* Simultaneous open */ 550 return NFCT_TCP_ACCEPT; 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 swin = win << sender->td_scale; 559 sender->td_maxwin = (swin == 0 ? 1 : swin); 560 sender->td_maxend = end + sender->td_maxwin; 561 if (receiver->td_maxwin == 0) { 562 /* We haven't seen traffic in the other 563 * direction yet but we have to tweak window 564 * tracking to pass III and IV until that 565 * happens. 566 */ 567 receiver->td_end = receiver->td_maxend = sack; 568 } else if (sack == receiver->td_end + 1) { 569 /* Likely a reply to a keepalive. 570 * Needed for III. 571 */ 572 receiver->td_end++; 573 } 574 575 } 576 } else if (tcph->syn && 577 after(end, sender->td_end) && 578 (state->state == TCP_CONNTRACK_SYN_SENT || 579 state->state == TCP_CONNTRACK_SYN_RECV)) { 580 /* 581 * RFC 793: "if a TCP is reinitialized ... then it need 582 * not wait at all; it must only be sure to use sequence 583 * numbers larger than those recently used." 584 * 585 * Re-init state for this direction, just like for the first 586 * syn(-ack) reply, it might differ in seq, ack or tcp options. 587 */ 588 tcp_init_sender(sender, receiver, 589 skb, dataoff, tcph, 590 end, win, dir); 591 592 if (dir == IP_CT_DIR_REPLY && !tcph->ack) 593 return NFCT_TCP_ACCEPT; 594 } 595 596 if (!(tcph->ack)) { 597 /* 598 * If there is no ACK, just pretend it was set and OK. 599 */ 600 ack = sack = receiver->td_end; 601 } else if (((tcp_flag_word(tcph) & (TCP_FLAG_ACK|TCP_FLAG_RST)) == 602 (TCP_FLAG_ACK|TCP_FLAG_RST)) 603 && (ack == 0)) { 604 /* 605 * Broken TCP stacks, that set ACK in RST packets as well 606 * with zero ack value. 607 */ 608 ack = sack = receiver->td_end; 609 } 610 611 if (tcph->rst && seq == 0 && state->state == TCP_CONNTRACK_SYN_SENT) 612 /* 613 * RST sent answering SYN. 614 */ 615 seq = end = sender->td_end; 616 617 seq_ok = before(seq, sender->td_maxend + 1); 618 if (!seq_ok) { 619 u32 overshot = end - sender->td_maxend + 1; 620 bool ack_ok; 621 622 ack_ok = after(sack, receiver->td_end - MAXACKWINDOW(sender) - 1); 623 in_recv_win = receiver->td_maxwin && 624 after(end, sender->td_end - receiver->td_maxwin - 1); 625 626 if (in_recv_win && 627 ack_ok && 628 overshot <= receiver->td_maxwin && 629 before(sack, receiver->td_end + 1)) { 630 /* Work around TCPs that send more bytes than allowed by 631 * the receive window. 632 * 633 * If the (marked as invalid) packet is allowed to pass by 634 * the ruleset and the peer acks this data, then its possible 635 * all future packets will trigger 'ACK is over upper bound' check. 636 * 637 * Thus if only the sequence check fails then do update td_end so 638 * possible ACK for this data can update internal state. 639 */ 640 sender->td_end = end; 641 sender->flags |= IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED; 642 643 return nf_tcp_log_invalid(skb, ct, hook_state, sender, NFCT_TCP_IGNORE, 644 "%u bytes more than expected", overshot); 645 } 646 647 return nf_tcp_log_invalid(skb, ct, hook_state, sender, NFCT_TCP_INVALID, 648 "SEQ is over upper bound %u (over the window of the receiver)", 649 sender->td_maxend + 1); 650 } 651 652 if (!before(sack, receiver->td_end + 1)) 653 return nf_tcp_log_invalid(skb, ct, hook_state, sender, NFCT_TCP_INVALID, 654 "ACK is over upper bound %u (ACKed data not seen yet)", 655 receiver->td_end + 1); 656 657 /* Is the ending sequence in the receive window (if available)? */ 658 in_recv_win = !receiver->td_maxwin || 659 after(end, sender->td_end - receiver->td_maxwin - 1); 660 if (!in_recv_win) 661 return nf_tcp_log_invalid(skb, ct, hook_state, sender, NFCT_TCP_IGNORE, 662 "SEQ is under lower bound %u (already ACKed data retransmitted)", 663 sender->td_end - receiver->td_maxwin - 1); 664 if (!after(sack, receiver->td_end - MAXACKWINDOW(sender) - 1)) 665 return nf_tcp_log_invalid(skb, ct, hook_state, sender, NFCT_TCP_IGNORE, 666 "ignored ACK under lower bound %u (possible overly delayed)", 667 receiver->td_end - MAXACKWINDOW(sender) - 1); 668 669 /* Take into account window scaling (RFC 1323). */ 670 if (!tcph->syn) 671 win <<= sender->td_scale; 672 673 /* Update sender data. */ 674 swin = win + (sack - ack); 675 if (sender->td_maxwin < swin) 676 sender->td_maxwin = swin; 677 if (after(end, sender->td_end)) { 678 sender->td_end = end; 679 sender->flags |= IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED; 680 } 681 if (tcph->ack) { 682 if (!(sender->flags & IP_CT_TCP_FLAG_MAXACK_SET)) { 683 sender->td_maxack = ack; 684 sender->flags |= IP_CT_TCP_FLAG_MAXACK_SET; 685 } else if (after(ack, sender->td_maxack)) { 686 sender->td_maxack = ack; 687 } 688 } 689 690 /* Update receiver data. */ 691 if (receiver->td_maxwin != 0 && after(end, sender->td_maxend)) 692 receiver->td_maxwin += end - sender->td_maxend; 693 if (after(sack + win, receiver->td_maxend - 1)) { 694 receiver->td_maxend = sack + win; 695 if (win == 0) 696 receiver->td_maxend++; 697 } 698 if (ack == receiver->td_end) 699 receiver->flags &= ~IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED; 700 701 /* Check retransmissions. */ 702 if (index == TCP_ACK_SET) { 703 if (state->last_dir == dir && 704 state->last_seq == seq && 705 state->last_ack == ack && 706 state->last_end == end && 707 state->last_win == win_raw) { 708 state->retrans++; 709 } else { 710 state->last_dir = dir; 711 state->last_seq = seq; 712 state->last_ack = ack; 713 state->last_end = end; 714 state->last_win = win_raw; 715 state->retrans = 0; 716 } 717 } 718 719 return NFCT_TCP_ACCEPT; 720} 721 722static void __cold nf_tcp_handle_invalid(struct nf_conn *ct, 723 enum ip_conntrack_dir dir, 724 int index, 725 const struct sk_buff *skb, 726 const struct nf_hook_state *hook_state) 727{ 728 const unsigned int *timeouts; 729 const struct nf_tcp_net *tn; 730 unsigned int timeout; 731 u32 expires; 732 733 if (!test_bit(IPS_ASSURED_BIT, &ct->status) || 734 test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status)) 735 return; 736 737 /* We don't want to have connections hanging around in ESTABLISHED 738 * state for long time 'just because' conntrack deemed a FIN/RST 739 * out-of-window. 740 * 741 * Shrink the timeout just like when there is unacked data. 742 * This speeds up eviction of 'dead' connections where the 743 * connection and conntracks internal state are out of sync. 744 */ 745 switch (index) { 746 case TCP_RST_SET: 747 case TCP_FIN_SET: 748 break; 749 default: 750 return; 751 } 752 753 if (ct->proto.tcp.last_dir != dir && 754 (ct->proto.tcp.last_index == TCP_FIN_SET || 755 ct->proto.tcp.last_index == TCP_RST_SET)) { 756 expires = nf_ct_expires(ct); 757 if (expires < 120 * HZ) 758 return; 759 760 tn = nf_tcp_pernet(nf_ct_net(ct)); 761 timeouts = nf_ct_timeout_lookup(ct); 762 if (!timeouts) 763 timeouts = tn->timeouts; 764 765 timeout = READ_ONCE(timeouts[TCP_CONNTRACK_UNACK]); 766 if (expires > timeout) { 767 nf_ct_l4proto_log_invalid(skb, ct, hook_state, 768 "packet (index %d, dir %d) response for index %d lower timeout to %u", 769 index, dir, ct->proto.tcp.last_index, timeout); 770 771 WRITE_ONCE(ct->timeout, timeout + nfct_time_stamp); 772 } 773 } else { 774 ct->proto.tcp.last_index = index; 775 ct->proto.tcp.last_dir = dir; 776 } 777} 778 779/* table of valid flag combinations - PUSH, ECE and CWR are always valid */ 780static const u8 tcp_valid_flags[(TCPHDR_FIN|TCPHDR_SYN|TCPHDR_RST|TCPHDR_ACK| 781 TCPHDR_URG) + 1] = 782{ 783 [TCPHDR_SYN] = 1, 784 [TCPHDR_SYN|TCPHDR_URG] = 1, 785 [TCPHDR_SYN|TCPHDR_ACK] = 1, 786 [TCPHDR_RST] = 1, 787 [TCPHDR_RST|TCPHDR_ACK] = 1, 788 [TCPHDR_FIN|TCPHDR_ACK] = 1, 789 [TCPHDR_FIN|TCPHDR_ACK|TCPHDR_URG] = 1, 790 [TCPHDR_ACK] = 1, 791 [TCPHDR_ACK|TCPHDR_URG] = 1, 792}; 793 794static void tcp_error_log(const struct sk_buff *skb, 795 const struct nf_hook_state *state, 796 const char *msg) 797{ 798 nf_l4proto_log_invalid(skb, state, IPPROTO_TCP, "%s", msg); 799} 800 801/* Protect conntrack agaist broken packets. Code taken from ipt_unclean.c. */ 802static bool tcp_error(const struct tcphdr *th, 803 struct sk_buff *skb, 804 unsigned int dataoff, 805 const struct nf_hook_state *state) 806{ 807 unsigned int tcplen = skb->len - dataoff; 808 u8 tcpflags; 809 810 /* Not whole TCP header or malformed packet */ 811 if (th->doff*4 < sizeof(struct tcphdr) || tcplen < th->doff*4) { 812 tcp_error_log(skb, state, "truncated packet"); 813 return true; 814 } 815 816 /* Checksum invalid? Ignore. 817 * We skip checking packets on the outgoing path 818 * because the checksum is assumed to be correct. 819 */ 820 /* FIXME: Source route IP option packets --RR */ 821 if (state->net->ct.sysctl_checksum && 822 state->hook == NF_INET_PRE_ROUTING && 823 nf_checksum(skb, state->hook, dataoff, IPPROTO_TCP, state->pf)) { 824 tcp_error_log(skb, state, "bad checksum"); 825 return true; 826 } 827 828 /* Check TCP flags. */ 829 tcpflags = (tcp_flag_byte(th) & ~(TCPHDR_ECE|TCPHDR_CWR|TCPHDR_PSH)); 830 if (!tcp_valid_flags[tcpflags]) { 831 tcp_error_log(skb, state, "invalid tcp flag combination"); 832 return true; 833 } 834 835 return false; 836} 837 838static noinline bool tcp_new(struct nf_conn *ct, const struct sk_buff *skb, 839 unsigned int dataoff, 840 const struct tcphdr *th, 841 const struct nf_hook_state *state) 842{ 843 enum tcp_conntrack new_state; 844 struct net *net = nf_ct_net(ct); 845 const struct nf_tcp_net *tn = nf_tcp_pernet(net); 846 847 /* Don't need lock here: this conntrack not in circulation yet */ 848 new_state = tcp_conntracks[0][get_conntrack_index(th)][TCP_CONNTRACK_NONE]; 849 850 /* Invalid: delete conntrack */ 851 if (new_state >= TCP_CONNTRACK_MAX) { 852 tcp_error_log(skb, state, "invalid new"); 853 return false; 854 } 855 856 if (new_state == TCP_CONNTRACK_SYN_SENT) { 857 memset(&ct->proto.tcp, 0, sizeof(ct->proto.tcp)); 858 /* SYN packet */ 859 ct->proto.tcp.seen[0].td_end = 860 segment_seq_plus_len(ntohl(th->seq), skb->len, 861 dataoff, th); 862 ct->proto.tcp.seen[0].td_maxwin = ntohs(th->window); 863 if (ct->proto.tcp.seen[0].td_maxwin == 0) 864 ct->proto.tcp.seen[0].td_maxwin = 1; 865 ct->proto.tcp.seen[0].td_maxend = 866 ct->proto.tcp.seen[0].td_end; 867 868 tcp_options(skb, dataoff, th, &ct->proto.tcp.seen[0]); 869 } else if (tn->tcp_loose == 0) { 870 /* Don't try to pick up connections. */ 871 return false; 872 } else { 873 memset(&ct->proto.tcp, 0, sizeof(ct->proto.tcp)); 874 /* 875 * We are in the middle of a connection, 876 * its history is lost for us. 877 * Let's try to use the data from the packet. 878 */ 879 ct->proto.tcp.seen[0].td_end = 880 segment_seq_plus_len(ntohl(th->seq), skb->len, 881 dataoff, th); 882 ct->proto.tcp.seen[0].td_maxwin = ntohs(th->window); 883 if (ct->proto.tcp.seen[0].td_maxwin == 0) 884 ct->proto.tcp.seen[0].td_maxwin = 1; 885 ct->proto.tcp.seen[0].td_maxend = 886 ct->proto.tcp.seen[0].td_end + 887 ct->proto.tcp.seen[0].td_maxwin; 888 889 /* We assume SACK and liberal window checking to handle 890 * window scaling */ 891 ct->proto.tcp.seen[0].flags = 892 ct->proto.tcp.seen[1].flags = IP_CT_TCP_FLAG_SACK_PERM | 893 IP_CT_TCP_FLAG_BE_LIBERAL; 894 } 895 896 /* tcp_packet will set them */ 897 ct->proto.tcp.last_index = TCP_NONE_SET; 898 return true; 899} 900 901static bool tcp_can_early_drop(const struct nf_conn *ct) 902{ 903 switch (ct->proto.tcp.state) { 904 case TCP_CONNTRACK_FIN_WAIT: 905 case TCP_CONNTRACK_LAST_ACK: 906 case TCP_CONNTRACK_TIME_WAIT: 907 case TCP_CONNTRACK_CLOSE: 908 case TCP_CONNTRACK_CLOSE_WAIT: 909 return true; 910 default: 911 break; 912 } 913 914 return false; 915} 916 917void nf_conntrack_tcp_set_closing(struct nf_conn *ct) 918{ 919 enum tcp_conntrack old_state; 920 const unsigned int *timeouts; 921 u32 timeout; 922 923 if (!nf_ct_is_confirmed(ct)) 924 return; 925 926 spin_lock_bh(&ct->lock); 927 old_state = ct->proto.tcp.state; 928 ct->proto.tcp.state = TCP_CONNTRACK_CLOSE; 929 930 if (old_state == TCP_CONNTRACK_CLOSE || 931 test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status)) { 932 spin_unlock_bh(&ct->lock); 933 return; 934 } 935 936 timeouts = nf_ct_timeout_lookup(ct); 937 if (!timeouts) { 938 const struct nf_tcp_net *tn; 939 940 tn = nf_tcp_pernet(nf_ct_net(ct)); 941 timeouts = tn->timeouts; 942 } 943 944 timeout = timeouts[TCP_CONNTRACK_CLOSE]; 945 WRITE_ONCE(ct->timeout, timeout + nfct_time_stamp); 946 947 spin_unlock_bh(&ct->lock); 948 949 nf_conntrack_event_cache(IPCT_PROTOINFO, ct); 950} 951 952static void nf_ct_tcp_state_reset(struct ip_ct_tcp_state *state) 953{ 954 state->td_end = 0; 955 state->td_maxend = 0; 956 state->td_maxwin = 0; 957 state->td_maxack = 0; 958 state->td_scale = 0; 959 state->flags &= IP_CT_TCP_FLAG_BE_LIBERAL; 960} 961 962/* Returns verdict for packet, or -1 for invalid. */ 963int nf_conntrack_tcp_packet(struct nf_conn *ct, 964 struct sk_buff *skb, 965 unsigned int dataoff, 966 enum ip_conntrack_info ctinfo, 967 const struct nf_hook_state *state) 968{ 969 struct net *net = nf_ct_net(ct); 970 struct nf_tcp_net *tn = nf_tcp_pernet(net); 971 enum tcp_conntrack new_state, old_state; 972 unsigned int index, *timeouts; 973 enum nf_ct_tcp_action res; 974 enum ip_conntrack_dir dir; 975 const struct tcphdr *th; 976 struct tcphdr _tcph; 977 unsigned long timeout; 978 979 th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph); 980 if (th == NULL) 981 return -NF_ACCEPT; 982 983 if (tcp_error(th, skb, dataoff, state)) 984 return -NF_ACCEPT; 985 986 if (!nf_ct_is_confirmed(ct) && !tcp_new(ct, skb, dataoff, th, state)) 987 return -NF_ACCEPT; 988 989 spin_lock_bh(&ct->lock); 990 old_state = ct->proto.tcp.state; 991 dir = CTINFO2DIR(ctinfo); 992 index = get_conntrack_index(th); 993 new_state = tcp_conntracks[dir][index][old_state]; 994 995 switch (new_state) { 996 case TCP_CONNTRACK_SYN_SENT: 997 if (old_state < TCP_CONNTRACK_TIME_WAIT) 998 break; 999 /* RFC 1122: "When a connection is closed actively, 1000 * it MUST linger in TIME-WAIT state for a time 2xMSL 1001 * (Maximum Segment Lifetime). However, it MAY accept 1002 * a new SYN from the remote TCP to reopen the connection 1003 * directly from TIME-WAIT state, if..." 1004 * We ignore the conditions because we are in the 1005 * TIME-WAIT state anyway. 1006 * 1007 * Handle aborted connections: we and the server 1008 * think there is an existing connection but the client 1009 * aborts it and starts a new one. 1010 */ 1011 if (((ct->proto.tcp.seen[dir].flags 1012 | ct->proto.tcp.seen[!dir].flags) 1013 & IP_CT_TCP_FLAG_CLOSE_INIT) 1014 || (ct->proto.tcp.last_dir == dir 1015 && ct->proto.tcp.last_index == TCP_RST_SET)) { 1016 /* Attempt to reopen a closed/aborted connection. 1017 * Delete this connection and look up again. */ 1018 spin_unlock_bh(&ct->lock); 1019 1020 /* Only repeat if we can actually remove the timer. 1021 * Destruction may already be in progress in process 1022 * context and we must give it a chance to terminate. 1023 */ 1024 if (nf_ct_kill(ct)) 1025 return -NF_REPEAT; 1026 return NF_DROP; 1027 } 1028 fallthrough; 1029 case TCP_CONNTRACK_IGNORE: 1030 /* Ignored packets: 1031 * 1032 * Our connection entry may be out of sync, so ignore 1033 * packets which may signal the real connection between 1034 * the client and the server. 1035 * 1036 * a) SYN in ORIGINAL 1037 * b) SYN/ACK in REPLY 1038 * c) ACK in reply direction after initial SYN in original. 1039 * 1040 * If the ignored packet is invalid, the receiver will send 1041 * a RST we'll catch below. 1042 */ 1043 if (index == TCP_SYNACK_SET 1044 && ct->proto.tcp.last_index == TCP_SYN_SET 1045 && ct->proto.tcp.last_dir != dir 1046 && ntohl(th->ack_seq) == ct->proto.tcp.last_end) { 1047 /* b) This SYN/ACK acknowledges a SYN that we earlier 1048 * ignored as invalid. This means that the client and 1049 * the server are both in sync, while the firewall is 1050 * not. We get in sync from the previously annotated 1051 * values. 1052 */ 1053 old_state = TCP_CONNTRACK_SYN_SENT; 1054 new_state = TCP_CONNTRACK_SYN_RECV; 1055 ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_end = 1056 ct->proto.tcp.last_end; 1057 ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_maxend = 1058 ct->proto.tcp.last_end; 1059 ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_maxwin = 1060 ct->proto.tcp.last_win == 0 ? 1061 1 : ct->proto.tcp.last_win; 1062 ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_scale = 1063 ct->proto.tcp.last_wscale; 1064 ct->proto.tcp.last_flags &= ~IP_CT_EXP_CHALLENGE_ACK; 1065 ct->proto.tcp.seen[ct->proto.tcp.last_dir].flags = 1066 ct->proto.tcp.last_flags; 1067 nf_ct_tcp_state_reset(&ct->proto.tcp.seen[dir]); 1068 break; 1069 } 1070 ct->proto.tcp.last_index = index; 1071 ct->proto.tcp.last_dir = dir; 1072 ct->proto.tcp.last_seq = ntohl(th->seq); 1073 ct->proto.tcp.last_end = 1074 segment_seq_plus_len(ntohl(th->seq), skb->len, dataoff, th); 1075 ct->proto.tcp.last_win = ntohs(th->window); 1076 1077 /* a) This is a SYN in ORIGINAL. The client and the server 1078 * may be in sync but we are not. In that case, we annotate 1079 * the TCP options and let the packet go through. If it is a 1080 * valid SYN packet, the server will reply with a SYN/ACK, and 1081 * then we'll get in sync. Otherwise, the server potentially 1082 * responds with a challenge ACK if implementing RFC5961. 1083 */ 1084 if (index == TCP_SYN_SET && dir == IP_CT_DIR_ORIGINAL) { 1085 struct ip_ct_tcp_state seen = {}; 1086 1087 ct->proto.tcp.last_flags = 1088 ct->proto.tcp.last_wscale = 0; 1089 tcp_options(skb, dataoff, th, &seen); 1090 if (seen.flags & IP_CT_TCP_FLAG_WINDOW_SCALE) { 1091 ct->proto.tcp.last_flags |= 1092 IP_CT_TCP_FLAG_WINDOW_SCALE; 1093 ct->proto.tcp.last_wscale = seen.td_scale; 1094 } 1095 if (seen.flags & IP_CT_TCP_FLAG_SACK_PERM) { 1096 ct->proto.tcp.last_flags |= 1097 IP_CT_TCP_FLAG_SACK_PERM; 1098 } 1099 /* Mark the potential for RFC5961 challenge ACK, 1100 * this pose a special problem for LAST_ACK state 1101 * as ACK is intrepretated as ACKing last FIN. 1102 */ 1103 if (old_state == TCP_CONNTRACK_LAST_ACK) 1104 ct->proto.tcp.last_flags |= 1105 IP_CT_EXP_CHALLENGE_ACK; 1106 } 1107 1108 /* possible challenge ack reply to syn */ 1109 if (old_state == TCP_CONNTRACK_SYN_SENT && 1110 index == TCP_ACK_SET && 1111 dir == IP_CT_DIR_REPLY) 1112 ct->proto.tcp.last_ack = ntohl(th->ack_seq); 1113 1114 spin_unlock_bh(&ct->lock); 1115 nf_ct_l4proto_log_invalid(skb, ct, state, 1116 "packet (index %d) in dir %d ignored, state %s", 1117 index, dir, 1118 tcp_conntrack_names[old_state]); 1119 return NF_ACCEPT; 1120 case TCP_CONNTRACK_MAX: 1121 /* Special case for SYN proxy: when the SYN to the server or 1122 * the SYN/ACK from the server is lost, the client may transmit 1123 * a keep-alive packet while in SYN_SENT state. This needs to 1124 * be associated with the original conntrack entry in order to 1125 * generate a new SYN with the correct sequence number. 1126 */ 1127 if (nfct_synproxy(ct) && old_state == TCP_CONNTRACK_SYN_SENT && 1128 index == TCP_ACK_SET && dir == IP_CT_DIR_ORIGINAL && 1129 ct->proto.tcp.last_dir == IP_CT_DIR_ORIGINAL && 1130 ct->proto.tcp.seen[dir].td_end - 1 == ntohl(th->seq)) { 1131 pr_debug("nf_ct_tcp: SYN proxy client keep alive\n"); 1132 spin_unlock_bh(&ct->lock); 1133 return NF_ACCEPT; 1134 } 1135 1136 /* Invalid packet */ 1137 spin_unlock_bh(&ct->lock); 1138 nf_ct_l4proto_log_invalid(skb, ct, state, 1139 "packet (index %d) in dir %d invalid, state %s", 1140 index, dir, 1141 tcp_conntrack_names[old_state]); 1142 return -NF_ACCEPT; 1143 case TCP_CONNTRACK_TIME_WAIT: 1144 /* RFC5961 compliance cause stack to send "challenge-ACK" 1145 * e.g. in response to spurious SYNs. Conntrack MUST 1146 * not believe this ACK is acking last FIN. 1147 */ 1148 if (old_state == TCP_CONNTRACK_LAST_ACK && 1149 index == TCP_ACK_SET && 1150 ct->proto.tcp.last_dir != dir && 1151 ct->proto.tcp.last_index == TCP_SYN_SET && 1152 (ct->proto.tcp.last_flags & IP_CT_EXP_CHALLENGE_ACK)) { 1153 /* Detected RFC5961 challenge ACK */ 1154 ct->proto.tcp.last_flags &= ~IP_CT_EXP_CHALLENGE_ACK; 1155 spin_unlock_bh(&ct->lock); 1156 nf_ct_l4proto_log_invalid(skb, ct, state, "challenge-ack ignored"); 1157 return NF_ACCEPT; /* Don't change state */ 1158 } 1159 break; 1160 case TCP_CONNTRACK_SYN_SENT2: 1161 /* tcp_conntracks table is not smart enough to handle 1162 * simultaneous open. 1163 */ 1164 ct->proto.tcp.last_flags |= IP_CT_TCP_SIMULTANEOUS_OPEN; 1165 break; 1166 case TCP_CONNTRACK_SYN_RECV: 1167 if (dir == IP_CT_DIR_REPLY && index == TCP_ACK_SET && 1168 ct->proto.tcp.last_flags & IP_CT_TCP_SIMULTANEOUS_OPEN) 1169 new_state = TCP_CONNTRACK_ESTABLISHED; 1170 break; 1171 case TCP_CONNTRACK_CLOSE: 1172 if (index != TCP_RST_SET) 1173 break; 1174 1175 /* If we are closing, tuple might have been re-used already. 1176 * last_index, last_ack, and all other ct fields used for 1177 * sequence/window validation are outdated in that case. 1178 * 1179 * As the conntrack can already be expired by GC under pressure, 1180 * just skip validation checks. 1181 */ 1182 if (tcp_can_early_drop(ct)) 1183 goto in_window; 1184 1185 /* td_maxack might be outdated if we let a SYN through earlier */ 1186 if ((ct->proto.tcp.seen[!dir].flags & IP_CT_TCP_FLAG_MAXACK_SET) && 1187 ct->proto.tcp.last_index != TCP_SYN_SET) { 1188 u32 seq = ntohl(th->seq); 1189 1190 /* If we are not in established state and SEQ=0 this is most 1191 * likely an answer to a SYN we let go through above (last_index 1192 * can be updated due to out-of-order ACKs). 1193 */ 1194 if (seq == 0 && !nf_conntrack_tcp_established(ct)) 1195 break; 1196 1197 if (before(seq, ct->proto.tcp.seen[!dir].td_maxack) && 1198 !tn->tcp_ignore_invalid_rst) { 1199 /* Invalid RST */ 1200 spin_unlock_bh(&ct->lock); 1201 nf_ct_l4proto_log_invalid(skb, ct, state, "invalid rst"); 1202 return -NF_ACCEPT; 1203 } 1204 1205 if (!nf_conntrack_tcp_established(ct) || 1206 seq == ct->proto.tcp.seen[!dir].td_maxack) 1207 break; 1208 1209 /* Check if rst is part of train, such as 1210 * foo:80 > bar:4379: P, 235946583:235946602(19) ack 42 1211 * foo:80 > bar:4379: R, 235946602:235946602(0) ack 42 1212 */ 1213 if (ct->proto.tcp.last_index == TCP_ACK_SET && 1214 ct->proto.tcp.last_dir == dir && 1215 seq == ct->proto.tcp.last_end) 1216 break; 1217 1218 /* ... RST sequence number doesn't match exactly, keep 1219 * established state to allow a possible challenge ACK. 1220 */ 1221 new_state = old_state; 1222 } 1223 if (((test_bit(IPS_SEEN_REPLY_BIT, &ct->status) 1224 && ct->proto.tcp.last_index == TCP_SYN_SET) 1225 || (!test_bit(IPS_ASSURED_BIT, &ct->status) 1226 && ct->proto.tcp.last_index == TCP_ACK_SET)) 1227 && ntohl(th->ack_seq) == ct->proto.tcp.last_end) { 1228 /* RST sent to invalid SYN or ACK we had let through 1229 * at a) and c) above: 1230 * 1231 * a) SYN was in window then 1232 * c) we hold a half-open connection. 1233 * 1234 * Delete our connection entry. 1235 * We skip window checking, because packet might ACK 1236 * segments we ignored. */ 1237 goto in_window; 1238 } 1239 1240 /* Reset in response to a challenge-ack we let through earlier */ 1241 if (old_state == TCP_CONNTRACK_SYN_SENT && 1242 ct->proto.tcp.last_index == TCP_ACK_SET && 1243 ct->proto.tcp.last_dir == IP_CT_DIR_REPLY && 1244 ntohl(th->seq) == ct->proto.tcp.last_ack) 1245 goto in_window; 1246 1247 break; 1248 default: 1249 /* Keep compilers happy. */ 1250 break; 1251 } 1252 1253 res = tcp_in_window(ct, dir, index, 1254 skb, dataoff, th, state); 1255 switch (res) { 1256 case NFCT_TCP_IGNORE: 1257 spin_unlock_bh(&ct->lock); 1258 return NF_ACCEPT; 1259 case NFCT_TCP_INVALID: 1260 nf_tcp_handle_invalid(ct, dir, index, skb, state); 1261 spin_unlock_bh(&ct->lock); 1262 return -NF_ACCEPT; 1263 case NFCT_TCP_ACCEPT: 1264 break; 1265 } 1266 in_window: 1267 /* From now on we have got in-window packets */ 1268 ct->proto.tcp.last_index = index; 1269 ct->proto.tcp.last_dir = dir; 1270 1271 ct->proto.tcp.state = new_state; 1272 if (old_state != new_state 1273 && new_state == TCP_CONNTRACK_FIN_WAIT) 1274 ct->proto.tcp.seen[dir].flags |= IP_CT_TCP_FLAG_CLOSE_INIT; 1275 1276 timeouts = nf_ct_timeout_lookup(ct); 1277 if (!timeouts) 1278 timeouts = tn->timeouts; 1279 1280 if (ct->proto.tcp.retrans >= tn->tcp_max_retrans && 1281 timeouts[new_state] > timeouts[TCP_CONNTRACK_RETRANS]) 1282 timeout = timeouts[TCP_CONNTRACK_RETRANS]; 1283 else if (unlikely(index == TCP_RST_SET)) 1284 timeout = timeouts[TCP_CONNTRACK_CLOSE]; 1285 else if ((ct->proto.tcp.seen[0].flags | ct->proto.tcp.seen[1].flags) & 1286 IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED && 1287 timeouts[new_state] > timeouts[TCP_CONNTRACK_UNACK]) 1288 timeout = timeouts[TCP_CONNTRACK_UNACK]; 1289 else if (ct->proto.tcp.last_win == 0 && 1290 timeouts[new_state] > timeouts[TCP_CONNTRACK_RETRANS]) 1291 timeout = timeouts[TCP_CONNTRACK_RETRANS]; 1292 else 1293 timeout = timeouts[new_state]; 1294 spin_unlock_bh(&ct->lock); 1295 1296 if (new_state != old_state) 1297 nf_conntrack_event_cache(IPCT_PROTOINFO, ct); 1298 1299 if (!test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) { 1300 /* If only reply is a RST, we can consider ourselves not to 1301 have an established connection: this is a fairly common 1302 problem case, so we can delete the conntrack 1303 immediately. --RR */ 1304 if (th->rst) { 1305 nf_ct_kill_acct(ct, ctinfo, skb); 1306 return NF_ACCEPT; 1307 } 1308 1309 if (index == TCP_SYN_SET && old_state == TCP_CONNTRACK_SYN_SENT) { 1310 /* do not renew timeout on SYN retransmit. 1311 * 1312 * Else port reuse by client or NAT middlebox can keep 1313 * entry alive indefinitely (including nat info). 1314 */ 1315 return NF_ACCEPT; 1316 } 1317 1318 /* ESTABLISHED without SEEN_REPLY, i.e. mid-connection 1319 * pickup with loose=1. Avoid large ESTABLISHED timeout. 1320 */ 1321 if (new_state == TCP_CONNTRACK_ESTABLISHED && 1322 timeout > timeouts[TCP_CONNTRACK_UNACK]) 1323 timeout = timeouts[TCP_CONNTRACK_UNACK]; 1324 } else if (!test_bit(IPS_ASSURED_BIT, &ct->status) 1325 && (old_state == TCP_CONNTRACK_SYN_RECV 1326 || old_state == TCP_CONNTRACK_ESTABLISHED) 1327 && new_state == TCP_CONNTRACK_ESTABLISHED) { 1328 /* Set ASSURED if we see valid ack in ESTABLISHED 1329 after SYN_RECV or a valid answer for a picked up 1330 connection. */ 1331 set_bit(IPS_ASSURED_BIT, &ct->status); 1332 nf_conntrack_event_cache(IPCT_ASSURED, ct); 1333 } 1334 nf_ct_refresh_acct(ct, ctinfo, skb, timeout); 1335 1336 return NF_ACCEPT; 1337} 1338 1339#if IS_ENABLED(CONFIG_NF_CT_NETLINK) 1340 1341#include <linux/netfilter/nfnetlink.h> 1342#include <linux/netfilter/nfnetlink_conntrack.h> 1343 1344static int tcp_to_nlattr(struct sk_buff *skb, struct nlattr *nla, 1345 struct nf_conn *ct, bool destroy) 1346{ 1347 struct nlattr *nest_parms; 1348 struct nf_ct_tcp_flags tmp = {}; 1349 1350 spin_lock_bh(&ct->lock); 1351 nest_parms = nla_nest_start(skb, CTA_PROTOINFO_TCP); 1352 if (!nest_parms) 1353 goto nla_put_failure; 1354 1355 if (nla_put_u8(skb, CTA_PROTOINFO_TCP_STATE, ct->proto.tcp.state)) 1356 goto nla_put_failure; 1357 1358 if (destroy) 1359 goto skip_state; 1360 1361 if (nla_put_u8(skb, CTA_PROTOINFO_TCP_WSCALE_ORIGINAL, 1362 ct->proto.tcp.seen[0].td_scale) || 1363 nla_put_u8(skb, CTA_PROTOINFO_TCP_WSCALE_REPLY, 1364 ct->proto.tcp.seen[1].td_scale)) 1365 goto nla_put_failure; 1366 1367 tmp.flags = ct->proto.tcp.seen[0].flags; 1368 if (nla_put(skb, CTA_PROTOINFO_TCP_FLAGS_ORIGINAL, 1369 sizeof(struct nf_ct_tcp_flags), &tmp)) 1370 goto nla_put_failure; 1371 1372 tmp.flags = ct->proto.tcp.seen[1].flags; 1373 if (nla_put(skb, CTA_PROTOINFO_TCP_FLAGS_REPLY, 1374 sizeof(struct nf_ct_tcp_flags), &tmp)) 1375 goto nla_put_failure; 1376skip_state: 1377 spin_unlock_bh(&ct->lock); 1378 nla_nest_end(skb, nest_parms); 1379 1380 return 0; 1381 1382nla_put_failure: 1383 spin_unlock_bh(&ct->lock); 1384 return -1; 1385} 1386 1387static const struct nla_policy tcp_nla_policy[CTA_PROTOINFO_TCP_MAX+1] = { 1388 [CTA_PROTOINFO_TCP_STATE] = { .type = NLA_U8 }, 1389 [CTA_PROTOINFO_TCP_WSCALE_ORIGINAL] = { .type = NLA_U8 }, 1390 [CTA_PROTOINFO_TCP_WSCALE_REPLY] = { .type = NLA_U8 }, 1391 [CTA_PROTOINFO_TCP_FLAGS_ORIGINAL] = { .len = sizeof(struct nf_ct_tcp_flags) }, 1392 [CTA_PROTOINFO_TCP_FLAGS_REPLY] = { .len = sizeof(struct nf_ct_tcp_flags) }, 1393}; 1394 1395#define TCP_NLATTR_SIZE ( \ 1396 NLA_ALIGN(NLA_HDRLEN + 1) + \ 1397 NLA_ALIGN(NLA_HDRLEN + 1) + \ 1398 NLA_ALIGN(NLA_HDRLEN + sizeof(struct nf_ct_tcp_flags)) + \ 1399 NLA_ALIGN(NLA_HDRLEN + sizeof(struct nf_ct_tcp_flags))) 1400 1401static int nlattr_to_tcp(struct nlattr *cda[], struct nf_conn *ct) 1402{ 1403 struct nlattr *pattr = cda[CTA_PROTOINFO_TCP]; 1404 struct nlattr *tb[CTA_PROTOINFO_TCP_MAX+1]; 1405 int err; 1406 1407 /* updates could not contain anything about the private 1408 * protocol info, in that case skip the parsing */ 1409 if (!pattr) 1410 return 0; 1411 1412 err = nla_parse_nested_deprecated(tb, CTA_PROTOINFO_TCP_MAX, pattr, 1413 tcp_nla_policy, NULL); 1414 if (err < 0) 1415 return err; 1416 1417 if (tb[CTA_PROTOINFO_TCP_STATE] && 1418 nla_get_u8(tb[CTA_PROTOINFO_TCP_STATE]) >= TCP_CONNTRACK_MAX) 1419 return -EINVAL; 1420 1421 spin_lock_bh(&ct->lock); 1422 if (tb[CTA_PROTOINFO_TCP_STATE]) 1423 ct->proto.tcp.state = nla_get_u8(tb[CTA_PROTOINFO_TCP_STATE]); 1424 1425 if (tb[CTA_PROTOINFO_TCP_FLAGS_ORIGINAL]) { 1426 struct nf_ct_tcp_flags *attr = 1427 nla_data(tb[CTA_PROTOINFO_TCP_FLAGS_ORIGINAL]); 1428 ct->proto.tcp.seen[0].flags &= ~attr->mask; 1429 ct->proto.tcp.seen[0].flags |= attr->flags & attr->mask; 1430 } 1431 1432 if (tb[CTA_PROTOINFO_TCP_FLAGS_REPLY]) { 1433 struct nf_ct_tcp_flags *attr = 1434 nla_data(tb[CTA_PROTOINFO_TCP_FLAGS_REPLY]); 1435 ct->proto.tcp.seen[1].flags &= ~attr->mask; 1436 ct->proto.tcp.seen[1].flags |= attr->flags & attr->mask; 1437 } 1438 1439 if (tb[CTA_PROTOINFO_TCP_WSCALE_ORIGINAL] && 1440 tb[CTA_PROTOINFO_TCP_WSCALE_REPLY] && 1441 ct->proto.tcp.seen[0].flags & IP_CT_TCP_FLAG_WINDOW_SCALE && 1442 ct->proto.tcp.seen[1].flags & IP_CT_TCP_FLAG_WINDOW_SCALE) { 1443 ct->proto.tcp.seen[0].td_scale = 1444 nla_get_u8(tb[CTA_PROTOINFO_TCP_WSCALE_ORIGINAL]); 1445 ct->proto.tcp.seen[1].td_scale = 1446 nla_get_u8(tb[CTA_PROTOINFO_TCP_WSCALE_REPLY]); 1447 } 1448 spin_unlock_bh(&ct->lock); 1449 1450 return 0; 1451} 1452 1453static unsigned int tcp_nlattr_tuple_size(void) 1454{ 1455 static unsigned int size __read_mostly; 1456 1457 if (!size) 1458 size = nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1); 1459 1460 return size; 1461} 1462#endif 1463 1464#ifdef CONFIG_NF_CONNTRACK_TIMEOUT 1465 1466#include <linux/netfilter/nfnetlink.h> 1467#include <linux/netfilter/nfnetlink_cttimeout.h> 1468 1469static int tcp_timeout_nlattr_to_obj(struct nlattr *tb[], 1470 struct net *net, void *data) 1471{ 1472 struct nf_tcp_net *tn = nf_tcp_pernet(net); 1473 unsigned int *timeouts = data; 1474 int i; 1475 1476 if (!timeouts) 1477 timeouts = tn->timeouts; 1478 /* set default TCP timeouts. */ 1479 for (i=0; i<TCP_CONNTRACK_TIMEOUT_MAX; i++) 1480 timeouts[i] = tn->timeouts[i]; 1481 1482 if (tb[CTA_TIMEOUT_TCP_SYN_SENT]) { 1483 timeouts[TCP_CONNTRACK_SYN_SENT] = 1484 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_SYN_SENT]))*HZ; 1485 } 1486 1487 if (tb[CTA_TIMEOUT_TCP_SYN_RECV]) { 1488 timeouts[TCP_CONNTRACK_SYN_RECV] = 1489 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_SYN_RECV]))*HZ; 1490 } 1491 if (tb[CTA_TIMEOUT_TCP_ESTABLISHED]) { 1492 timeouts[TCP_CONNTRACK_ESTABLISHED] = 1493 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_ESTABLISHED]))*HZ; 1494 } 1495 if (tb[CTA_TIMEOUT_TCP_FIN_WAIT]) { 1496 timeouts[TCP_CONNTRACK_FIN_WAIT] = 1497 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_FIN_WAIT]))*HZ; 1498 } 1499 if (tb[CTA_TIMEOUT_TCP_CLOSE_WAIT]) { 1500 timeouts[TCP_CONNTRACK_CLOSE_WAIT] = 1501 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_CLOSE_WAIT]))*HZ; 1502 } 1503 if (tb[CTA_TIMEOUT_TCP_LAST_ACK]) { 1504 timeouts[TCP_CONNTRACK_LAST_ACK] = 1505 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_LAST_ACK]))*HZ; 1506 } 1507 if (tb[CTA_TIMEOUT_TCP_TIME_WAIT]) { 1508 timeouts[TCP_CONNTRACK_TIME_WAIT] = 1509 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_TIME_WAIT]))*HZ; 1510 } 1511 if (tb[CTA_TIMEOUT_TCP_CLOSE]) { 1512 timeouts[TCP_CONNTRACK_CLOSE] = 1513 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_CLOSE]))*HZ; 1514 } 1515 if (tb[CTA_TIMEOUT_TCP_SYN_SENT2]) { 1516 timeouts[TCP_CONNTRACK_SYN_SENT2] = 1517 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_SYN_SENT2]))*HZ; 1518 } 1519 if (tb[CTA_TIMEOUT_TCP_RETRANS]) { 1520 timeouts[TCP_CONNTRACK_RETRANS] = 1521 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_RETRANS]))*HZ; 1522 } 1523 if (tb[CTA_TIMEOUT_TCP_UNACK]) { 1524 timeouts[TCP_CONNTRACK_UNACK] = 1525 ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_UNACK]))*HZ; 1526 } 1527 1528 timeouts[CTA_TIMEOUT_TCP_UNSPEC] = timeouts[CTA_TIMEOUT_TCP_SYN_SENT]; 1529 return 0; 1530} 1531 1532static int 1533tcp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data) 1534{ 1535 const unsigned int *timeouts = data; 1536 1537 if (nla_put_be32(skb, CTA_TIMEOUT_TCP_SYN_SENT, 1538 htonl(timeouts[TCP_CONNTRACK_SYN_SENT] / HZ)) || 1539 nla_put_be32(skb, CTA_TIMEOUT_TCP_SYN_RECV, 1540 htonl(timeouts[TCP_CONNTRACK_SYN_RECV] / HZ)) || 1541 nla_put_be32(skb, CTA_TIMEOUT_TCP_ESTABLISHED, 1542 htonl(timeouts[TCP_CONNTRACK_ESTABLISHED] / HZ)) || 1543 nla_put_be32(skb, CTA_TIMEOUT_TCP_FIN_WAIT, 1544 htonl(timeouts[TCP_CONNTRACK_FIN_WAIT] / HZ)) || 1545 nla_put_be32(skb, CTA_TIMEOUT_TCP_CLOSE_WAIT, 1546 htonl(timeouts[TCP_CONNTRACK_CLOSE_WAIT] / HZ)) || 1547 nla_put_be32(skb, CTA_TIMEOUT_TCP_LAST_ACK, 1548 htonl(timeouts[TCP_CONNTRACK_LAST_ACK] / HZ)) || 1549 nla_put_be32(skb, CTA_TIMEOUT_TCP_TIME_WAIT, 1550 htonl(timeouts[TCP_CONNTRACK_TIME_WAIT] / HZ)) || 1551 nla_put_be32(skb, CTA_TIMEOUT_TCP_CLOSE, 1552 htonl(timeouts[TCP_CONNTRACK_CLOSE] / HZ)) || 1553 nla_put_be32(skb, CTA_TIMEOUT_TCP_SYN_SENT2, 1554 htonl(timeouts[TCP_CONNTRACK_SYN_SENT2] / HZ)) || 1555 nla_put_be32(skb, CTA_TIMEOUT_TCP_RETRANS, 1556 htonl(timeouts[TCP_CONNTRACK_RETRANS] / HZ)) || 1557 nla_put_be32(skb, CTA_TIMEOUT_TCP_UNACK, 1558 htonl(timeouts[TCP_CONNTRACK_UNACK] / HZ))) 1559 goto nla_put_failure; 1560 return 0; 1561 1562nla_put_failure: 1563 return -ENOSPC; 1564} 1565 1566static const struct nla_policy tcp_timeout_nla_policy[CTA_TIMEOUT_TCP_MAX+1] = { 1567 [CTA_TIMEOUT_TCP_SYN_SENT] = { .type = NLA_U32 }, 1568 [CTA_TIMEOUT_TCP_SYN_RECV] = { .type = NLA_U32 }, 1569 [CTA_TIMEOUT_TCP_ESTABLISHED] = { .type = NLA_U32 }, 1570 [CTA_TIMEOUT_TCP_FIN_WAIT] = { .type = NLA_U32 }, 1571 [CTA_TIMEOUT_TCP_CLOSE_WAIT] = { .type = NLA_U32 }, 1572 [CTA_TIMEOUT_TCP_LAST_ACK] = { .type = NLA_U32 }, 1573 [CTA_TIMEOUT_TCP_TIME_WAIT] = { .type = NLA_U32 }, 1574 [CTA_TIMEOUT_TCP_CLOSE] = { .type = NLA_U32 }, 1575 [CTA_TIMEOUT_TCP_SYN_SENT2] = { .type = NLA_U32 }, 1576 [CTA_TIMEOUT_TCP_RETRANS] = { .type = NLA_U32 }, 1577 [CTA_TIMEOUT_TCP_UNACK] = { .type = NLA_U32 }, 1578}; 1579#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */ 1580 1581void nf_conntrack_tcp_init_net(struct net *net) 1582{ 1583 struct nf_tcp_net *tn = nf_tcp_pernet(net); 1584 int i; 1585 1586 for (i = 0; i < TCP_CONNTRACK_TIMEOUT_MAX; i++) 1587 tn->timeouts[i] = tcp_timeouts[i]; 1588 1589 /* timeouts[0] is unused, make it same as SYN_SENT so 1590 * ->timeouts[0] contains 'new' timeout, like udp or icmp. 1591 */ 1592 tn->timeouts[0] = tcp_timeouts[TCP_CONNTRACK_SYN_SENT]; 1593 1594 /* If it is set to zero, we disable picking up already established 1595 * connections. 1596 */ 1597 tn->tcp_loose = 1; 1598 1599 /* "Be conservative in what you do, 1600 * be liberal in what you accept from others." 1601 * If it's non-zero, we mark only out of window RST segments as INVALID. 1602 */ 1603 tn->tcp_be_liberal = 0; 1604 1605 /* If it's non-zero, we turn off RST sequence number check */ 1606 tn->tcp_ignore_invalid_rst = 0; 1607 1608 /* Max number of the retransmitted packets without receiving an (acceptable) 1609 * ACK from the destination. If this number is reached, a shorter timer 1610 * will be started. 1611 */ 1612 tn->tcp_max_retrans = 3; 1613 1614#if IS_ENABLED(CONFIG_NF_FLOW_TABLE) 1615 tn->offload_timeout = 30 * HZ; 1616#endif 1617} 1618 1619const struct nf_conntrack_l4proto nf_conntrack_l4proto_tcp = 1620{ 1621 .l4proto = IPPROTO_TCP, 1622#ifdef CONFIG_NF_CONNTRACK_PROCFS 1623 .print_conntrack = tcp_print_conntrack, 1624#endif 1625 .can_early_drop = tcp_can_early_drop, 1626#if IS_ENABLED(CONFIG_NF_CT_NETLINK) 1627 .to_nlattr = tcp_to_nlattr, 1628 .from_nlattr = nlattr_to_tcp, 1629 .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr, 1630 .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple, 1631 .nlattr_tuple_size = tcp_nlattr_tuple_size, 1632 .nlattr_size = TCP_NLATTR_SIZE, 1633 .nla_policy = nf_ct_port_nla_policy, 1634#endif 1635#ifdef CONFIG_NF_CONNTRACK_TIMEOUT 1636 .ctnl_timeout = { 1637 .nlattr_to_obj = tcp_timeout_nlattr_to_obj, 1638 .obj_to_nlattr = tcp_timeout_obj_to_nlattr, 1639 .nlattr_max = CTA_TIMEOUT_TCP_MAX, 1640 .obj_size = sizeof(unsigned int) * 1641 TCP_CONNTRACK_TIMEOUT_MAX, 1642 .nla_policy = tcp_timeout_nla_policy, 1643 }, 1644#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */ 1645}; 1646