net/netfilter/nf_conntrack_proto_tcp.c

   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 /* "Be conservative in what you do,
  35     be liberal in what you accept from others."
  36     If it's non-zero, we mark only out of window RST segments as INVALID. */
  37 static int nf_ct_tcp_be_liberal __read_mostly = 0;
  38
  39 /* If it is set to zero, we disable picking up already established
  40    connections. */
  41 static int nf_ct_tcp_loose __read_mostly = 1;
  42
  43 /* Max number of the retransmitted packets without receiving an (acceptable)
  44    ACK from the destination. If this number is reached, a shorter timer
  45    will be started. */
  46 static int nf_ct_tcp_max_retrans __read_mostly = 3;
  47
  48   /* FIXME: Examine ipfilter's timeouts and conntrack transitions more
  49      closely.  They're more complex. --RR */
  50
  51 static const char *const tcp_conntrack_names[] = {
  52         "NONE",
  53         "SYN_SENT",
  54         "SYN_RECV",
  55         "ESTABLISHED",
  56         "FIN_WAIT",
  57         "CLOSE_WAIT",
  58         "LAST_ACK",
  59         "TIME_WAIT",
  60         "CLOSE",
  61         "SYN_SENT2",
  62 };
  63
  64 #define SECS * HZ
  65 #define MINS * 60 SECS
  66 #define HOURS * 60 MINS
  67 #define DAYS * 24 HOURS
  68
  69 static const unsigned int tcp_timeouts[TCP_CONNTRACK_TIMEOUT_MAX] = {
  70         [TCP_CONNTRACK_SYN_SENT]        = 2 MINS,
  71         [TCP_CONNTRACK_SYN_RECV]        = 60 SECS,
  72         [TCP_CONNTRACK_ESTABLISHED]     = 5 DAYS,
  73         [TCP_CONNTRACK_FIN_WAIT]        = 2 MINS,
  74         [TCP_CONNTRACK_CLOSE_WAIT]      = 60 SECS,
  75         [TCP_CONNTRACK_LAST_ACK]        = 30 SECS,
  76         [TCP_CONNTRACK_TIME_WAIT]       = 2 MINS,
  77         [TCP_CONNTRACK_CLOSE]           = 10 SECS,
  78         [TCP_CONNTRACK_SYN_SENT2]       = 2 MINS,
  79 /* RFC1122 says the R2 limit should be at least 100 seconds.
  80    Linux uses 15 packets as limit, which corresponds
  81    to ~13-30min depending on RTO. */
  82         [TCP_CONNTRACK_RETRANS]         = 5 MINS,
  83         [TCP_CONNTRACK_UNACK]           = 5 MINS,
  84 };
  85
  86 #define sNO TCP_CONNTRACK_NONE
  87 #define sSS TCP_CONNTRACK_SYN_SENT
  88 #define sSR TCP_CONNTRACK_SYN_RECV
  89 #define sES TCP_CONNTRACK_ESTABLISHED
  90 #define sFW TCP_CONNTRACK_FIN_WAIT
  91 #define sCW TCP_CONNTRACK_CLOSE_WAIT
  92 #define sLA TCP_CONNTRACK_LAST_ACK
  93 #define sTW TCP_CONNTRACK_TIME_WAIT
  94 #define sCL TCP_CONNTRACK_CLOSE
  95 #define sS2 TCP_CONNTRACK_SYN_SENT2
  96 #define sIV TCP_CONNTRACK_MAX
  97 #define sIG TCP_CONNTRACK_IGNORE
  98
  99 /* What TCP flags are set from RST/SYN/FIN/ACK. */
 100 enum tcp_bit_set {
 101         TCP_SYN_SET,
 102         TCP_SYNACK_SET,
 103         TCP_FIN_SET,
 104         TCP_ACK_SET,
 105         TCP_RST_SET,
 106         TCP_NONE_SET,
 107 };
 108
 109 /*
 110  * The TCP state transition table needs a few words...
 111  *
 112  * We are the man in the middle. All the packets go through us
 113  * but might get lost in transit to the destination.
 114  * It is assumed that the destinations can't receive segments
 115  * we haven't seen.
 116  *
 117  * The checked segment is in window, but our windows are *not*
 118  * equivalent with the ones of the sender/receiver. We always
 119  * try to guess the state of the current sender.
 120  *
 121  * The meaning of the states are:
 122  *
 123  * NONE:        initial state
 124  * SYN_SENT:    SYN-only packet seen
 125  * SYN_SENT2:   SYN-only packet seen from reply dir, simultaneous open
 126  * SYN_RECV:    SYN-ACK packet seen
 127  * ESTABLISHED: ACK packet seen
 128  * FIN_WAIT:    FIN packet seen
 129  * CLOSE_WAIT:  ACK seen (after FIN)
 130  * LAST_ACK:    FIN seen (after FIN)
 131  * TIME_WAIT:   last ACK seen
 132  * CLOSE:       closed connection (RST)
 133  *
 134  * Packets marked as IGNORED (sIG):
 135  *      if they may be either invalid or valid
 136  *      and the receiver may send back a connection
 137  *      closing RST or a SYN/ACK.
 138  *
 139  * Packets marked as INVALID (sIV):
 140  *      if we regard them as truly invalid packets
 141  */
 142 static const u8 tcp_conntracks[2][6][TCP_CONNTRACK_MAX] = {
 143         {
 144 /* ORIGINAL */
 145 /*           sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2   */
 146 /*syn*/    { sSS, sSS, sIG, sIG, sIG, sIG, sIG, sSS, sSS, sS2 },
 147 /*
 148  *      sNO -> sSS      Initialize a new connection
 149  *      sSS -> sSS      Retransmitted SYN
 150  *      sS2 -> sS2      Late retransmitted SYN
 151  *      sSR -> sIG
 152  *      sES -> sIG      Error: SYNs in window outside the SYN_SENT state
 153  *                      are errors. Receiver will reply with RST
 154  *                      and close the connection.
 155  *                      Or we are not in sync and hold a dead connection.
 156  *      sFW -> sIG
 157  *      sCW -> sIG
 158  *      sLA -> sIG
 159  *      sTW -> sSS      Reopened connection (RFC 1122).
 160  *      sCL -> sSS
 161  */
 162 /*           sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2   */
 163 /*synack*/ { sIV, sIV, sSR, sIV, sIV, sIV, sIV, sIV, sIV, sSR },
 164 /*
 165  *      sNO -> sIV      Too late and no reason to do anything
 166  *      sSS -> sIV      Client can't send SYN and then SYN/ACK
 167  *      sS2 -> sSR      SYN/ACK sent to SYN2 in simultaneous open
 168  *      sSR -> sSR      Late retransmitted SYN/ACK in simultaneous open
 169  *      sES -> sIV      Invalid SYN/ACK packets sent by the client
 170  *      sFW -> sIV
 171  *      sCW -> sIV
 172  *      sLA -> sIV
 173  *      sTW -> sIV
 174  *      sCL -> sIV
 175  */
 176 /*           sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2   */
 177 /*fin*/    { sIV, sIV, sFW, sFW, sLA, sLA, sLA, sTW, sCL, sIV },
 178 /*
 179  *      sNO -> sIV      Too late and no reason to do anything...
 180  *      sSS -> sIV      Client migth not send FIN in this state:
 181  *                      we enforce waiting for a SYN/ACK reply first.
 182  *      sS2 -> sIV
 183  *      sSR -> sFW      Close started.
 184  *      sES -> sFW
 185  *      sFW -> sLA      FIN seen in both directions, waiting for
 186  *                      the last ACK.
 187  *                      Migth be a retransmitted FIN as well...
 188  *      sCW -> sLA
 189  *      sLA -> sLA      Retransmitted FIN. Remain in the same state.
 190  *      sTW -> sTW
 191  *      sCL -> sCL
 192  */
 193 /*           sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2   */
 194 /*ack*/    { sES, sIV, sES, sES, sCW, sCW, sTW, sTW, sCL, sIV },
 195 /*
 196  *      sNO -> sES      Assumed.
 197  *      sSS -> sIV      ACK is invalid: we haven't seen a SYN/ACK yet.
 198  *      sS2 -> sIV
 199  *      sSR -> sES      Established state is reached.
 200  *      sES -> sES      :-)
 201  *      sFW -> sCW      Normal close request answered by ACK.
 202  *      sCW -> sCW
 203  *      sLA -> sTW      Last ACK detected (RFC5961 challenged)
 204  *      sTW -> sTW      Retransmitted last ACK. Remain in the same state.
 205  *      sCL -> sCL
 206  */
 207 /*           sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2   */
 208 /*rst*/    { sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL },
 209 /*none*/   { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV }
 210         },
 211         {
 212 /* REPLY */
 213 /*           sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2   */
 214 /*syn*/    { sIV, sS2, sIV, sIV, sIV, sIV, sIV, sSS, sIV, sS2 },
 215 /*
 216  *      sNO -> sIV      Never reached.
 217  *      sSS -> sS2      Simultaneous open
 218  *      sS2 -> sS2      Retransmitted simultaneous SYN
 219  *      sSR -> sIV      Invalid SYN packets sent by the server
 220  *      sES -> sIV
 221  *      sFW -> sIV
 222  *      sCW -> sIV
 223  *      sLA -> sIV
 224  *      sTW -> sSS      Reopened connection, but server may have switched role
 225  *      sCL -> sIV
 226  */
 227 /*           sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2   */
 228 /*synack*/ { sIV, sSR, sIG, sIG, sIG, sIG, sIG, sIG, sIG, sSR },
 229 /*
 230  *      sSS -> sSR      Standard open.
 231  *      sS2 -> sSR      Simultaneous open
 232  *      sSR -> sIG      Retransmitted SYN/ACK, ignore it.
 233  *      sES -> sIG      Late retransmitted SYN/ACK?
 234  *      sFW -> sIG      Might be SYN/ACK answering ignored SYN
 235  *      sCW -> sIG
 236  *      sLA -> sIG
 237  *      sTW -> sIG
 238  *      sCL -> sIG
 239  */
 240 /*           sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2   */
 241 /*fin*/    { sIV, sIV, sFW, sFW, sLA, sLA, sLA, sTW, sCL, sIV },
 242 /*
 243  *      sSS -> sIV      Server might not send FIN in this state.
 244  *      sS2 -> sIV
 245  *      sSR -> sFW      Close started.
 246  *      sES -> sFW
 247  *      sFW -> sLA      FIN seen in both directions.
 248  *      sCW -> sLA
 249  *      sLA -> sLA      Retransmitted FIN.
 250  *      sTW -> sTW
 251  *      sCL -> sCL
 252  */
 253 /*           sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2   */
 254 /*ack*/    { sIV, sIG, sSR, sES, sCW, sCW, sTW, sTW, sCL, sIG },
 255 /*
 256  *      sSS -> sIG      Might be a half-open connection.
 257  *      sS2 -> sIG
 258  *      sSR -> sSR      Might answer late resent SYN.
 259  *      sES -> sES      :-)
 260  *      sFW -> sCW      Normal close request answered by ACK.
 261  *      sCW -> sCW
 262  *      sLA -> sTW      Last ACK detected (RFC5961 challenged)
 263  *      sTW -> sTW      Retransmitted last ACK.
 264  *      sCL -> sCL
 265  */
 266 /*           sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2   */
 267 /*rst*/    { sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL },
 268 /*none*/   { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV }
 269         }
 270 };
 271
 272 #ifdef CONFIG_NF_CONNTRACK_PROCFS
 273 /* Print out the private part of the conntrack. */
 274 static void tcp_print_conntrack(struct seq_file *s, struct nf_conn *ct)
 275 {
 276         if (test_bit(IPS_OFFLOAD_BIT, &ct->status))
 277                 return;
 278
 279         seq_printf(s, "%s ", tcp_conntrack_names[ct->proto.tcp.state]);
 280 }
 281 #endif
 282
 283 static unsigned int get_conntrack_index(const struct tcphdr *tcph)
 284 {
 285         if (tcph->rst) return TCP_RST_SET;
 286         else if (tcph->syn) return (tcph->ack ? TCP_SYNACK_SET : TCP_SYN_SET);
 287         else if (tcph->fin) return TCP_FIN_SET;
 288         else if (tcph->ack) return TCP_ACK_SET;
 289         else return TCP_NONE_SET;
 290 }
 291
 292 /* TCP connection tracking based on 'Real Stateful TCP Packet Filtering
 293    in IP Filter' by Guido van Rooij.
 294
 295    http://www.sane.nl/events/sane2000/papers.html
 296    http://www.darkart.com/mirrors/www.obfuscation.org/ipf/
 297
 298    The boundaries and the conditions are changed according to RFC793:
 299    the packet must intersect the window (i.e. segments may be
 300    after the right or before the left edge) and thus receivers may ACK
 301    segments after the right edge of the window.
 302
 303         td_maxend = max(sack + max(win,1)) seen in reply packets
 304         td_maxwin = max(max(win, 1)) + (sack - ack) seen in sent packets
 305         td_maxwin += seq + len - sender.td_maxend
 306                         if seq + len > sender.td_maxend
 307         td_end    = max(seq + len) seen in sent packets
 308
 309    I.   Upper bound for valid data:     seq <= sender.td_maxend
 310    II.  Lower bound for valid data:     seq + len >= sender.td_end - receiver.td_maxwin
 311    III. Upper bound for valid (s)ack:   sack <= receiver.td_end
 312    IV.  Lower bound for valid (s)ack:   sack >= receiver.td_end - MAXACKWINDOW
 313
 314    where sack is the highest right edge of sack block found in the packet
 315    or ack in the case of packet without SACK option.
 316
 317    The upper bound limit for a valid (s)ack is not ignored -
 318    we doesn't have to deal with fragments.
 319 */
 320
 321 static inline __u32 segment_seq_plus_len(__u32 seq,
 322                                          size_t len,
 323                                          unsigned int dataoff,
 324                                          const struct tcphdr *tcph)
 325 {
 326         /* XXX Should I use payload length field in IP/IPv6 header ?
 327          * - YK */
 328         return (seq + len - dataoff - tcph->doff*4
 329                 + (tcph->syn ? 1 : 0) + (tcph->fin ? 1 : 0));
 330 }
 331
 332 /* Fixme: what about big packets? */
 333 #define MAXACKWINCONST                  66000
 334 #define MAXACKWINDOW(sender)                                            \
 335         ((sender)->td_maxwin > MAXACKWINCONST ? (sender)->td_maxwin     \
 336                                               : MAXACKWINCONST)
 337
 338 /*
 339  * Simplified tcp_parse_options routine from tcp_input.c
 340  */
 341 static void tcp_options(const struct sk_buff *skb,
 342                         unsigned int dataoff,
 343                         const struct tcphdr *tcph,
 344                         struct ip_ct_tcp_state *state)
 345 {
 346         unsigned char buff[(15 * 4) - sizeof(struct tcphdr)];
 347         const unsigned char *ptr;
 348         int length = (tcph->doff*4) - sizeof(struct tcphdr);
 349
 350         if (!length)
 351                 return;
 352
 353         ptr = skb_header_pointer(skb, dataoff + sizeof(struct tcphdr),
 354                                  length, buff);
 355         BUG_ON(ptr == NULL);
 356
 357         state->td_scale = 0;
 358         state->flags &= IP_CT_TCP_FLAG_BE_LIBERAL;
 359
 360         while (length > 0) {
 361                 int opcode=*ptr++;
 362                 int opsize;
 363
 364                 switch (opcode) {
 365                 case TCPOPT_EOL:
 366                         return;
 367                 case TCPOPT_NOP:        /* Ref: RFC 793 section 3.1 */
 368                         length--;
 369                         continue;
 370                 default:
 371                         if (length < 2)
 372                                 return;
 373                         opsize=*ptr++;
 374                         if (opsize < 2) /* "silly options" */
 375                                 return;
 376                         if (opsize > length)
 377                                 return; /* don't parse partial options */
 378
 379                         if (opcode == TCPOPT_SACK_PERM
 380                             && opsize == TCPOLEN_SACK_PERM)
 381                                 state->flags |= IP_CT_TCP_FLAG_SACK_PERM;
 382                         else if (opcode == TCPOPT_WINDOW
 383                                  && opsize == TCPOLEN_WINDOW) {
 384                                 state->td_scale = *(u_int8_t *)ptr;
 385
 386                                 if (state->td_scale > TCP_MAX_WSCALE)
 387                                         state->td_scale = TCP_MAX_WSCALE;
 388
 389                                 state->flags |=
 390                                         IP_CT_TCP_FLAG_WINDOW_SCALE;
 391                         }
 392                         ptr += opsize - 2;
 393                         length -= opsize;
 394                 }
 395         }
 396 }
 397
 398 static void tcp_sack(const struct sk_buff *skb, unsigned int dataoff,
 399                      const struct tcphdr *tcph, __u32 *sack)
 400 {
 401         unsigned char buff[(15 * 4) - sizeof(struct tcphdr)];
 402         const unsigned char *ptr;
 403         int length = (tcph->doff*4) - sizeof(struct tcphdr);
 404         __u32 tmp;
 405
 406         if (!length)
 407                 return;
 408
 409         ptr = skb_header_pointer(skb, dataoff + sizeof(struct tcphdr),
 410                                  length, buff);
 411         BUG_ON(ptr == NULL);
 412
 413         /* Fast path for timestamp-only option */
 414         if (length == TCPOLEN_TSTAMP_ALIGNED
 415             && *(__be32 *)ptr == htonl((TCPOPT_NOP << 24)
 416                                        | (TCPOPT_NOP << 16)
 417                                        | (TCPOPT_TIMESTAMP << 8)
 418                                        | TCPOLEN_TIMESTAMP))
 419                 return;
 420
 421         while (length > 0) {
 422                 int opcode = *ptr++;
 423                 int opsize, i;
 424
 425                 switch (opcode) {
 426                 case TCPOPT_EOL:
 427                         return;
 428                 case TCPOPT_NOP:        /* Ref: RFC 793 section 3.1 */
 429                         length--;
 430                         continue;
 431                 default:
 432                         if (length < 2)
 433                                 return;
 434                         opsize = *ptr++;
 435                         if (opsize < 2) /* "silly options" */
 436                                 return;
 437                         if (opsize > length)
 438                                 return; /* don't parse partial options */
 439
 440                         if (opcode == TCPOPT_SACK
 441                             && opsize >= (TCPOLEN_SACK_BASE
 442                                           + TCPOLEN_SACK_PERBLOCK)
 443                             && !((opsize - TCPOLEN_SACK_BASE)
 444                                  % TCPOLEN_SACK_PERBLOCK)) {
 445                                 for (i = 0;
 446                                      i < (opsize - TCPOLEN_SACK_BASE);
 447                                      i += TCPOLEN_SACK_PERBLOCK) {
 448                                         tmp = get_unaligned_be32((__be32 *)(ptr+i)+1);
 449
 450                                         if (after(tmp, *sack))
 451                                                 *sack = tmp;
 452                                 }
 453                                 return;
 454                         }
 455                         ptr += opsize - 2;
 456                         length -= opsize;
 457                 }
 458         }
 459 }
 460
 461 static bool tcp_in_window(const struct nf_conn *ct,
 462                           struct ip_ct_tcp *state,
 463                           enum ip_conntrack_dir dir,
 464                           unsigned int index,
 465                           const struct sk_buff *skb,
 466                           unsigned int dataoff,
 467                           const struct tcphdr *tcph)
 468 {
 469         struct net *net = nf_ct_net(ct);
 470         struct nf_tcp_net *tn = nf_tcp_pernet(net);
 471         struct ip_ct_tcp_state *sender = &state->seen[dir];
 472         struct ip_ct_tcp_state *receiver = &state->seen[!dir];
 473         const struct nf_conntrack_tuple *tuple = &ct->tuplehash[dir].tuple;
 474         __u32 seq, ack, sack, end, win, swin;
 475         u16 win_raw;
 476         s32 receiver_offset;
 477         bool res, in_recv_win;
 478
 479         /*
 480          * Get the required data from the packet.
 481          */
 482         seq = ntohl(tcph->seq);
 483         ack = sack = ntohl(tcph->ack_seq);
 484         win_raw = ntohs(tcph->window);
 485         win = win_raw;
 486         end = segment_seq_plus_len(seq, skb->len, dataoff, tcph);
 487
 488         if (receiver->flags & IP_CT_TCP_FLAG_SACK_PERM)
 489                 tcp_sack(skb, dataoff, tcph, &sack);
 490
 491         /* Take into account NAT sequence number mangling */
 492         receiver_offset = nf_ct_seq_offset(ct, !dir, ack - 1);
 493         ack -= receiver_offset;
 494         sack -= receiver_offset;
 495
 496         pr_debug("tcp_in_window: START\n");
 497         pr_debug("tcp_in_window: ");
 498         nf_ct_dump_tuple(tuple);
 499         pr_debug("seq=%u ack=%u+(%d) sack=%u+(%d) win=%u end=%u\n",
 500                  seq, ack, receiver_offset, sack, receiver_offset, win, end);
 501         pr_debug("tcp_in_window: sender end=%u maxend=%u maxwin=%u scale=%i "
 502                  "receiver end=%u maxend=%u maxwin=%u scale=%i\n",
 503                  sender->td_end, sender->td_maxend, sender->td_maxwin,
 504                  sender->td_scale,
 505                  receiver->td_end, receiver->td_maxend, receiver->td_maxwin,
 506                  receiver->td_scale);
 507
 508         if (sender->td_maxwin == 0) {
 509                 /*
 510                  * Initialize sender data.
 511                  */
 512                 if (tcph->syn) {
 513                         /*
 514                          * SYN-ACK in reply to a SYN
 515                          * or SYN from reply direction in simultaneous open.
 516                          */
 517                         sender->td_end =
 518                         sender->td_maxend = end;
 519                         sender->td_maxwin = (win == 0 ? 1 : win);
 520
 521                         tcp_options(skb, dataoff, tcph, sender);
 522                         /*
 523                          * RFC 1323:
 524                          * Both sides must send the Window Scale option
 525                          * to enable window scaling in either direction.
 526                          */
 527                         if (!(sender->flags & IP_CT_TCP_FLAG_WINDOW_SCALE
 528                               && receiver->flags & IP_CT_TCP_FLAG_WINDOW_SCALE))
 529                                 sender->td_scale =
 530                                 receiver->td_scale = 0;
 531                         if (!tcph->ack)
 532                                 /* Simultaneous open */
 533                                 return true;
 534                 } else {
 535                         /*
 536                          * We are in the middle of a connection,
 537                          * its history is lost for us.
 538                          * Let's try to use the data from the packet.
 539                          */
 540                         sender->td_end = end;
 541                         swin = win << sender->td_scale;
 542                         sender->td_maxwin = (swin == 0 ? 1 : swin);
 543                         sender->td_maxend = end + sender->td_maxwin;
 544                         if (receiver->td_maxwin == 0) {
 545                                 /* We haven't seen traffic in the other
 546                                  * direction yet but we have to tweak window
 547                                  * tracking to pass III and IV until that
 548                                  * happens.
 549                                  */
 550                                 receiver->td_end = receiver->td_maxend = sack;
 551                         } else if (sack == receiver->td_end + 1) {
 552                                 /* Likely a reply to a keepalive.
 553                                  * Needed for III.
 554                                  */
 555                                 receiver->td_end++;
 556                         }
 557
 558                 }
 559         } else if (((state->state == TCP_CONNTRACK_SYN_SENT
 560                      && dir == IP_CT_DIR_ORIGINAL)
 561                    || (state->state == TCP_CONNTRACK_SYN_RECV
 562                      && dir == IP_CT_DIR_REPLY))
 563                    && after(end, sender->td_end)) {
 564                 /*
 565                  * RFC 793: "if a TCP is reinitialized ... then it need
 566                  * not wait at all; it must only be sure to use sequence
 567                  * numbers larger than those recently used."
 568                  */
 569                 sender->td_end =
 570                 sender->td_maxend = end;
 571                 sender->td_maxwin = (win == 0 ? 1 : win);
 572
 573                 tcp_options(skb, dataoff, tcph, sender);
 574         }
 575
 576         if (!(tcph->ack)) {
 577                 /*
 578                  * If there is no ACK, just pretend it was set and OK.
 579                  */
 580                 ack = sack = receiver->td_end;
 581         } else if (((tcp_flag_word(tcph) & (TCP_FLAG_ACK|TCP_FLAG_RST)) ==
 582                     (TCP_FLAG_ACK|TCP_FLAG_RST))
 583                    && (ack == 0)) {
 584                 /*
 585                  * Broken TCP stacks, that set ACK in RST packets as well
 586                  * with zero ack value.
 587                  */
 588                 ack = sack = receiver->td_end;
 589         }
 590
 591         if (tcph->rst && seq == 0 && state->state == TCP_CONNTRACK_SYN_SENT)
 592                 /*
 593                  * RST sent answering SYN.
 594                  */
 595                 seq = end = sender->td_end;
 596
 597         pr_debug("tcp_in_window: ");
 598         nf_ct_dump_tuple(tuple);
 599         pr_debug("seq=%u ack=%u+(%d) sack=%u+(%d) win=%u end=%u\n",
 600                  seq, ack, receiver_offset, sack, receiver_offset, win, end);
 601         pr_debug("tcp_in_window: sender end=%u maxend=%u maxwin=%u scale=%i "
 602                  "receiver end=%u maxend=%u maxwin=%u scale=%i\n",
 603                  sender->td_end, sender->td_maxend, sender->td_maxwin,
 604                  sender->td_scale,
 605                  receiver->td_end, receiver->td_maxend, receiver->td_maxwin,
 606                  receiver->td_scale);
 607
 608         /* Is the ending sequence in the receive window (if available)? */
 609         in_recv_win = !receiver->td_maxwin ||
 610                       after(end, sender->td_end - receiver->td_maxwin - 1);
 611
 612         pr_debug("tcp_in_window: I=%i II=%i III=%i IV=%i\n",
 613                  before(seq, sender->td_maxend + 1),
 614                  (in_recv_win ? 1 : 0),
 615                  before(sack, receiver->td_end + 1),
 616                  after(sack, receiver->td_end - MAXACKWINDOW(sender) - 1));
 617
 618         if (before(seq, sender->td_maxend + 1) &&
 619             in_recv_win &&
 620             before(sack, receiver->td_end + 1) &&
 621             after(sack, receiver->td_end - MAXACKWINDOW(sender) - 1)) {
 622                 /*
 623                  * Take into account window scaling (RFC 1323).
 624                  */
 625                 if (!tcph->syn)
 626                         win <<= sender->td_scale;
 627
 628                 /*
 629                  * Update sender data.
 630                  */
 631                 swin = win + (sack - ack);
 632                 if (sender->td_maxwin < swin)
 633                         sender->td_maxwin = swin;
 634                 if (after(end, sender->td_end)) {
 635                         sender->td_end = end;
 636                         sender->flags |= IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED;
 637                 }
 638                 if (tcph->ack) {
 639                         if (!(sender->flags & IP_CT_TCP_FLAG_MAXACK_SET)) {
 640                                 sender->td_maxack = ack;
 641                                 sender->flags |= IP_CT_TCP_FLAG_MAXACK_SET;
 642                         } else if (after(ack, sender->td_maxack))
 643                                 sender->td_maxack = ack;
 644                 }
 645
 646                 /*
 647                  * Update receiver data.
 648                  */
 649                 if (receiver->td_maxwin != 0 && after(end, sender->td_maxend))
 650                         receiver->td_maxwin += end - sender->td_maxend;
 651                 if (after(sack + win, receiver->td_maxend - 1)) {
 652                         receiver->td_maxend = sack + win;
 653                         if (win == 0)
 654                                 receiver->td_maxend++;
 655                 }
 656                 if (ack == receiver->td_end)
 657                         receiver->flags &= ~IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED;
 658
 659                 /*
 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
 666                             && state->last_end == end
 667                             && state->last_win == win_raw)
 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;
 674                                 state->last_win = win_raw;
 675                                 state->retrans = 0;
 676                         }
 677                 }
 678                 res = true;
 679         } else {
 680                 res = false;
 681                 if (sender->flags & IP_CT_TCP_FLAG_BE_LIBERAL ||
 682                     tn->tcp_be_liberal)
 683                         res = true;
 684                 if (!res) {
 685                         nf_ct_l4proto_log_invalid(skb, ct,
 686                         "%s",
 687                         before(seq, sender->td_maxend + 1) ?
 688                         in_recv_win ?
 689                         before(sack, receiver->td_end + 1) ?
 690                         after(sack, receiver->td_end - MAXACKWINDOW(sender) - 1) ? "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)");
 695                 }
 696         }
 697
 698         pr_debug("tcp_in_window: res=%u sender end=%u maxend=%u maxwin=%u "
 699                  "receiver end=%u maxend=%u maxwin=%u\n",
 700                  res, sender->td_end, sender->td_maxend, sender->td_maxwin,
 701                  receiver->td_end, receiver->td_maxend, receiver->td_maxwin);
 702
 703         return res;
 704 }
 705
 706 /* table of valid flag combinations - PUSH, ECE and CWR are always valid */
 707 static const u8 tcp_valid_flags[(TCPHDR_FIN|TCPHDR_SYN|TCPHDR_RST|TCPHDR_ACK|
 708                                  TCPHDR_URG) + 1] =
 709 {
 710         [TCPHDR_SYN]                            = 1,
 711         [TCPHDR_SYN|TCPHDR_URG]                 = 1,
 712         [TCPHDR_SYN|TCPHDR_ACK]                 = 1,
 713         [TCPHDR_RST]                            = 1,
 714         [TCPHDR_RST|TCPHDR_ACK]                 = 1,
 715         [TCPHDR_FIN|TCPHDR_ACK]                 = 1,
 716         [TCPHDR_FIN|TCPHDR_ACK|TCPHDR_URG]      = 1,
 717         [TCPHDR_ACK]                            = 1,
 718         [TCPHDR_ACK|TCPHDR_URG]                 = 1,
 719 };
 720
 721 static void tcp_error_log(const struct sk_buff *skb,
 722                           const struct nf_hook_state *state,
 723                           const char *msg)
 724 {
 725         nf_l4proto_log_invalid(skb, state->net, state->pf, IPPROTO_TCP, "%s", msg);
 726 }
 727
 728 /* Protect conntrack agaist broken packets. Code taken from ipt_unclean.c.  */
 729 static bool tcp_error(const struct tcphdr *th,
 730                       struct sk_buff *skb,
 731                       unsigned int dataoff,
 732                       const struct nf_hook_state *state)
 733 {
 734         unsigned int tcplen = skb->len - dataoff;
 735         u8 tcpflags;
 736
 737         /* Not whole TCP header or malformed packet */
 738         if (th->doff*4 < sizeof(struct tcphdr) || tcplen < th->doff*4) {
 739                 tcp_error_log(skb, state, "truncated packet");
 740                 return true;
 741         }
 742
 743         /* Checksum invalid? Ignore.
 744          * We skip checking packets on the outgoing path
 745          * because the checksum is assumed to be correct.
 746          */
 747         /* FIXME: Source route IP option packets --RR */
 748         if (state->net->ct.sysctl_checksum &&
 749             state->hook == NF_INET_PRE_ROUTING &&
 750             nf_checksum(skb, state->hook, dataoff, IPPROTO_TCP, state->pf)) {
 751                 tcp_error_log(skb, state, "bad checksum");
 752                 return true;
 753         }
 754
 755         /* Check TCP flags. */
 756         tcpflags = (tcp_flag_byte(th) & ~(TCPHDR_ECE|TCPHDR_CWR|TCPHDR_PSH));
 757         if (!tcp_valid_flags[tcpflags]) {
 758                 tcp_error_log(skb, state, "invalid tcp flag combination");
 759                 return true;
 760         }
 761
 762         return false;
 763 }
 764
 765 static noinline bool tcp_new(struct nf_conn *ct, const struct sk_buff *skb,
 766                              unsigned int dataoff,
 767                              const struct tcphdr *th)
 768 {
 769         enum tcp_conntrack new_state;
 770         struct net *net = nf_ct_net(ct);
 771         const struct nf_tcp_net *tn = nf_tcp_pernet(net);
 772         const struct ip_ct_tcp_state *sender = &ct->proto.tcp.seen[0];
 773         const struct ip_ct_tcp_state *receiver = &ct->proto.tcp.seen[1];
 774
 775         /* Don't need lock here: this conntrack not in circulation yet */
 776         new_state = tcp_conntracks[0][get_conntrack_index(th)][TCP_CONNTRACK_NONE];
 777
 778         /* Invalid: delete conntrack */
 779         if (new_state >= TCP_CONNTRACK_MAX) {
 780                 pr_debug("nf_ct_tcp: invalid new deleting.\n");
 781                 return false;
 782         }
 783
 784         if (new_state == TCP_CONNTRACK_SYN_SENT) {
 785                 memset(&ct->proto.tcp, 0, sizeof(ct->proto.tcp));
 786                 /* SYN packet */
 787                 ct->proto.tcp.seen[0].td_end =
 788                         segment_seq_plus_len(ntohl(th->seq), skb->len,
 789                                              dataoff, th);
 790                 ct->proto.tcp.seen[0].td_maxwin = ntohs(th->window);
 791                 if (ct->proto.tcp.seen[0].td_maxwin == 0)
 792                         ct->proto.tcp.seen[0].td_maxwin = 1;
 793                 ct->proto.tcp.seen[0].td_maxend =
 794                         ct->proto.tcp.seen[0].td_end;
 795
 796                 tcp_options(skb, dataoff, th, &ct->proto.tcp.seen[0]);
 797         } else if (tn->tcp_loose == 0) {
 798                 /* Don't try to pick up connections. */
 799                 return false;
 800         } else {
 801                 memset(&ct->proto.tcp, 0, sizeof(ct->proto.tcp));
 802                 /*
 803                  * We are in the middle of a connection,
 804                  * its history is lost for us.
 805                  * Let's try to use the data from the packet.
 806                  */
 807                 ct->proto.tcp.seen[0].td_end =
 808                         segment_seq_plus_len(ntohl(th->seq), skb->len,
 809                                              dataoff, th);
 810                 ct->proto.tcp.seen[0].td_maxwin = ntohs(th->window);
 811                 if (ct->proto.tcp.seen[0].td_maxwin == 0)
 812                         ct->proto.tcp.seen[0].td_maxwin = 1;
 813                 ct->proto.tcp.seen[0].td_maxend =
 814                         ct->proto.tcp.seen[0].td_end +
 815                         ct->proto.tcp.seen[0].td_maxwin;
 816
 817                 /* We assume SACK and liberal window checking to handle
 818                  * window scaling */
 819                 ct->proto.tcp.seen[0].flags =
 820                 ct->proto.tcp.seen[1].flags = IP_CT_TCP_FLAG_SACK_PERM |
 821                                               IP_CT_TCP_FLAG_BE_LIBERAL;
 822         }
 823
 824         /* tcp_packet will set them */
 825         ct->proto.tcp.last_index = TCP_NONE_SET;
 826
 827         pr_debug("%s: sender end=%u maxend=%u maxwin=%u scale=%i "
 828                  "receiver end=%u maxend=%u maxwin=%u scale=%i\n",
 829                  __func__,
 830                  sender->td_end, sender->td_maxend, sender->td_maxwin,
 831                  sender->td_scale,
 832                  receiver->td_end, receiver->td_maxend, receiver->td_maxwin,
 833                  receiver->td_scale);
 834         return true;
 835 }
 836
 837 static bool nf_conntrack_tcp_established(const struct nf_conn *ct)
 838 {
 839         return ct->proto.tcp.state == TCP_CONNTRACK_ESTABLISHED &&
 840                test_bit(IPS_ASSURED_BIT, &ct->status);
 841 }
 842
 843 static void nf_ct_tcp_state_reset(struct ip_ct_tcp_state *state)
 844 {
 845         state->td_end           = 0;
 846         state->td_maxend        = 0;
 847         state->td_maxwin        = 0;
 848         state->td_maxack        = 0;
 849         state->td_scale         = 0;
 850         state->flags            &= IP_CT_TCP_FLAG_BE_LIBERAL;
 851 }
 852
 853 /* Returns verdict for packet, or -1 for invalid. */
 854 int nf_conntrack_tcp_packet(struct nf_conn *ct,
 855                             struct sk_buff *skb,
 856                             unsigned int dataoff,
 857                             enum ip_conntrack_info ctinfo,
 858                             const struct nf_hook_state *state)
 859 {
 860         struct net *net = nf_ct_net(ct);
 861         struct nf_tcp_net *tn = nf_tcp_pernet(net);
 862         struct nf_conntrack_tuple *tuple;
 863         enum tcp_conntrack new_state, old_state;
 864         unsigned int index, *timeouts;
 865         enum ip_conntrack_dir dir;
 866         const struct tcphdr *th;
 867         struct tcphdr _tcph;
 868         unsigned long timeout;
 869
 870         th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph);
 871         if (th == NULL)
 872                 return -NF_ACCEPT;
 873
 874         if (tcp_error(th, skb, dataoff, state))
 875                 return -NF_ACCEPT;
 876
 877         if (!nf_ct_is_confirmed(ct) && !tcp_new(ct, skb, dataoff, th))
 878                 return -NF_ACCEPT;
 879
 880         spin_lock_bh(&ct->lock);
 881         old_state = ct->proto.tcp.state;
 882         dir = CTINFO2DIR(ctinfo);
 883         index = get_conntrack_index(th);
 884         new_state = tcp_conntracks[dir][index][old_state];
 885         tuple = &ct->tuplehash[dir].tuple;
 886
 887         switch (new_state) {
 888         case TCP_CONNTRACK_SYN_SENT:
 889                 if (old_state < TCP_CONNTRACK_TIME_WAIT)
 890                         break;
 891                 /* RFC 1122: "When a connection is closed actively,
 892                  * it MUST linger in TIME-WAIT state for a time 2xMSL
 893                  * (Maximum Segment Lifetime). However, it MAY accept
 894                  * a new SYN from the remote TCP to reopen the connection
 895                  * directly from TIME-WAIT state, if..."
 896                  * We ignore the conditions because we are in the
 897                  * TIME-WAIT state anyway.
 898                  *
 899                  * Handle aborted connections: we and the server
 900                  * think there is an existing connection but the client
 901                  * aborts it and starts a new one.
 902                  */
 903                 if (((ct->proto.tcp.seen[dir].flags
 904                       | ct->proto.tcp.seen[!dir].flags)
 905                      & IP_CT_TCP_FLAG_CLOSE_INIT)
 906                     || (ct->proto.tcp.last_dir == dir
 907                         && ct->proto.tcp.last_index == TCP_RST_SET)) {
 908                         /* Attempt to reopen a closed/aborted connection.
 909                          * Delete this connection and look up again. */
 910                         spin_unlock_bh(&ct->lock);
 911
 912                         /* Only repeat if we can actually remove the timer.
 913                          * Destruction may already be in progress in process
 914                          * context and we must give it a chance to terminate.
 915                          */
 916                         if (nf_ct_kill(ct))
 917                                 return -NF_REPEAT;
 918                         return NF_DROP;
 919                 }
 920                 fallthrough;
 921         case TCP_CONNTRACK_IGNORE:
 922                 /* Ignored packets:
 923                  *
 924                  * Our connection entry may be out of sync, so ignore
 925                  * packets which may signal the real connection between
 926                  * the client and the server.
 927                  *
 928                  * a) SYN in ORIGINAL
 929                  * b) SYN/ACK in REPLY
 930                  * c) ACK in reply direction after initial SYN in original.
 931                  *
 932                  * If the ignored packet is invalid, the receiver will send
 933                  * a RST we'll catch below.
 934                  */
 935                 if (index == TCP_SYNACK_SET
 936                     && ct->proto.tcp.last_index == TCP_SYN_SET
 937                     && ct->proto.tcp.last_dir != dir
 938                     && ntohl(th->ack_seq) == ct->proto.tcp.last_end) {
 939                         /* b) This SYN/ACK acknowledges a SYN that we earlier
 940                          * ignored as invalid. This means that the client and
 941                          * the server are both in sync, while the firewall is
 942                          * not. We get in sync from the previously annotated
 943                          * values.
 944                          */
 945                         old_state = TCP_CONNTRACK_SYN_SENT;
 946                         new_state = TCP_CONNTRACK_SYN_RECV;
 947                         ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_end =
 948                                 ct->proto.tcp.last_end;
 949                         ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_maxend =
 950                                 ct->proto.tcp.last_end;
 951                         ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_maxwin =
 952                                 ct->proto.tcp.last_win == 0 ?
 953                                         1 : ct->proto.tcp.last_win;
 954                         ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_scale =
 955                                 ct->proto.tcp.last_wscale;
 956                         ct->proto.tcp.last_flags &= ~IP_CT_EXP_CHALLENGE_ACK;
 957                         ct->proto.tcp.seen[ct->proto.tcp.last_dir].flags =
 958                                 ct->proto.tcp.last_flags;
 959                         nf_ct_tcp_state_reset(&ct->proto.tcp.seen[dir]);
 960                         break;
 961                 }
 962                 ct->proto.tcp.last_index = index;
 963                 ct->proto.tcp.last_dir = dir;
 964                 ct->proto.tcp.last_seq = ntohl(th->seq);
 965                 ct->proto.tcp.last_end =
 966                     segment_seq_plus_len(ntohl(th->seq), skb->len, dataoff, th);
 967                 ct->proto.tcp.last_win = ntohs(th->window);
 968
 969                 /* a) This is a SYN in ORIGINAL. The client and the server
 970                  * may be in sync but we are not. In that case, we annotate
 971                  * the TCP options and let the packet go through. If it is a
 972                  * valid SYN packet, the server will reply with a SYN/ACK, and
 973                  * then we'll get in sync. Otherwise, the server potentially
 974                  * responds with a challenge ACK if implementing RFC5961.
 975                  */
 976                 if (index == TCP_SYN_SET && dir == IP_CT_DIR_ORIGINAL) {
 977                         struct ip_ct_tcp_state seen = {};
 978
 979                         ct->proto.tcp.last_flags =
 980                         ct->proto.tcp.last_wscale = 0;
 981                         tcp_options(skb, dataoff, th, &seen);
 982                         if (seen.flags & IP_CT_TCP_FLAG_WINDOW_SCALE) {
 983                                 ct->proto.tcp.last_flags |=
 984                                         IP_CT_TCP_FLAG_WINDOW_SCALE;
 985                                 ct->proto.tcp.last_wscale = seen.td_scale;
 986                         }
 987                         if (seen.flags & IP_CT_TCP_FLAG_SACK_PERM) {
 988                                 ct->proto.tcp.last_flags |=
 989                                         IP_CT_TCP_FLAG_SACK_PERM;
 990                         }
 991                         /* Mark the potential for RFC5961 challenge ACK,
 992                          * this pose a special problem for LAST_ACK state
 993                          * as ACK is intrepretated as ACKing last FIN.
 994                          */
 995                         if (old_state == TCP_CONNTRACK_LAST_ACK)
 996                                 ct->proto.tcp.last_flags |=
 997                                         IP_CT_EXP_CHALLENGE_ACK;
 998                 }
 999                 spin_unlock_bh(&ct->lock);
1000                 nf_ct_l4proto_log_invalid(skb, ct, "invalid packet ignored in "
1001                                           "state %s ", tcp_conntrack_names[old_state]);
1002                 return NF_ACCEPT;
1003         case TCP_CONNTRACK_MAX:
1004                 /* Special case for SYN proxy: when the SYN to the server or
1005                  * the SYN/ACK from the server is lost, the client may transmit
1006                  * a keep-alive packet while in SYN_SENT state. This needs to
1007                  * be associated with the original conntrack entry in order to
1008                  * generate a new SYN with the correct sequence number.
1009                  */
1010                 if (nfct_synproxy(ct) && old_state == TCP_CONNTRACK_SYN_SENT &&
1011                     index == TCP_ACK_SET && dir == IP_CT_DIR_ORIGINAL &&
1012                     ct->proto.tcp.last_dir == IP_CT_DIR_ORIGINAL &&
1013                     ct->proto.tcp.seen[dir].td_end - 1 == ntohl(th->seq)) {
1014                         pr_debug("nf_ct_tcp: SYN proxy client keep alive\n");
1015                         spin_unlock_bh(&ct->lock);
1016                         return NF_ACCEPT;
1017                 }
1018
1019                 /* Invalid packet */
1020                 pr_debug("nf_ct_tcp: Invalid dir=%i index=%u ostate=%u\n",
1021                          dir, get_conntrack_index(th), old_state);
1022                 spin_unlock_bh(&ct->lock);
1023                 nf_ct_l4proto_log_invalid(skb, ct, "invalid state");
1024                 return -NF_ACCEPT;
1025         case TCP_CONNTRACK_TIME_WAIT:
1026                 /* RFC5961 compliance cause stack to send "challenge-ACK"
1027                  * e.g. in response to spurious SYNs.  Conntrack MUST
1028                  * not believe this ACK is acking last FIN.
1029                  */
1030                 if (old_state == TCP_CONNTRACK_LAST_ACK &&
1031                     index == TCP_ACK_SET &&
1032                     ct->proto.tcp.last_dir != dir &&
1033                     ct->proto.tcp.last_index == TCP_SYN_SET &&
1034                     (ct->proto.tcp.last_flags & IP_CT_EXP_CHALLENGE_ACK)) {
1035                         /* Detected RFC5961 challenge ACK */
1036                         ct->proto.tcp.last_flags &= ~IP_CT_EXP_CHALLENGE_ACK;
1037                         spin_unlock_bh(&ct->lock);
1038                         nf_ct_l4proto_log_invalid(skb, ct, "challenge-ack ignored");
1039                         return NF_ACCEPT; /* Don't change state */
1040                 }
1041                 break;
1042         case TCP_CONNTRACK_SYN_SENT2:
1043                 /* tcp_conntracks table is not smart enough to handle
1044                  * simultaneous open.
1045                  */
1046                 ct->proto.tcp.last_flags |= IP_CT_TCP_SIMULTANEOUS_OPEN;
1047                 break;
1048         case TCP_CONNTRACK_SYN_RECV:
1049                 if (dir == IP_CT_DIR_REPLY && index == TCP_ACK_SET &&
1050                     ct->proto.tcp.last_flags & IP_CT_TCP_SIMULTANEOUS_OPEN)
1051                         new_state = TCP_CONNTRACK_ESTABLISHED;
1052                 break;
1053         case TCP_CONNTRACK_CLOSE:
1054                 if (index != TCP_RST_SET)
1055                         break;
1056
1057                 if (ct->proto.tcp.seen[!dir].flags & IP_CT_TCP_FLAG_MAXACK_SET) {
1058                         u32 seq = ntohl(th->seq);
1059
1060                         if (before(seq, ct->proto.tcp.seen[!dir].td_maxack)) {
1061                                 /* Invalid RST  */
1062                                 spin_unlock_bh(&ct->lock);
1063                                 nf_ct_l4proto_log_invalid(skb, ct, "invalid rst");
1064                                 return -NF_ACCEPT;
1065                         }
1066
1067                         if (!nf_conntrack_tcp_established(ct) ||
1068                             seq == ct->proto.tcp.seen[!dir].td_maxack)
1069                                 break;
1070
1071                         /* Check if rst is part of train, such as
1072                          *   foo:80 > bar:4379: P, 235946583:235946602(19) ack 42
1073                          *   foo:80 > bar:4379: R, 235946602:235946602(0)  ack 42
1074                          */
1075                         if (ct->proto.tcp.last_index == TCP_ACK_SET &&
1076                             ct->proto.tcp.last_dir == dir &&
1077                             seq == ct->proto.tcp.last_end)
1078                                 break;
1079
1080                         /* ... RST sequence number doesn't match exactly, keep
1081                          * established state to allow a possible challenge ACK.
1082                          */
1083                         new_state = old_state;
1084                 }
1085                 if (((test_bit(IPS_SEEN_REPLY_BIT, &ct->status)
1086                          && ct->proto.tcp.last_index == TCP_SYN_SET)
1087                         || (!test_bit(IPS_ASSURED_BIT, &ct->status)
1088                             && ct->proto.tcp.last_index == TCP_ACK_SET))
1089                     && ntohl(th->ack_seq) == ct->proto.tcp.last_end) {
1090                         /* RST sent to invalid SYN or ACK we had let through
1091                          * at a) and c) above:
1092                          *
1093                          * a) SYN was in window then
1094                          * c) we hold a half-open connection.
1095                          *
1096                          * Delete our connection entry.
1097                          * We skip window checking, because packet might ACK
1098                          * segments we ignored. */
1099                         goto in_window;
1100                 }
1101                 break;
1102         default:
1103                 /* Keep compilers happy. */
1104                 break;
1105         }
1106
1107         if (!tcp_in_window(ct, &ct->proto.tcp, dir, index,
1108                            skb, dataoff, th)) {
1109                 spin_unlock_bh(&ct->lock);
1110                 return -NF_ACCEPT;
1111         }
1112      in_window:
1113         /* From now on we have got in-window packets */
1114         ct->proto.tcp.last_index = index;
1115         ct->proto.tcp.last_dir = dir;
1116
1117         pr_debug("tcp_conntracks: ");
1118         nf_ct_dump_tuple(tuple);
1119         pr_debug("syn=%i ack=%i fin=%i rst=%i old=%i new=%i\n",
1120                  (th->syn ? 1 : 0), (th->ack ? 1 : 0),
1121                  (th->fin ? 1 : 0), (th->rst ? 1 : 0),
1122                  old_state, new_state);
1123
1124         ct->proto.tcp.state = new_state;
1125         if (old_state != new_state
1126             && new_state == TCP_CONNTRACK_FIN_WAIT)
1127                 ct->proto.tcp.seen[dir].flags |= IP_CT_TCP_FLAG_CLOSE_INIT;
1128
1129         timeouts = nf_ct_timeout_lookup(ct);
1130         if (!timeouts)
1131                 timeouts = tn->timeouts;
1132
1133         if (ct->proto.tcp.retrans >= tn->tcp_max_retrans &&
1134             timeouts[new_state] > timeouts[TCP_CONNTRACK_RETRANS])
1135                 timeout = timeouts[TCP_CONNTRACK_RETRANS];
1136         else if (unlikely(index == TCP_RST_SET))
1137                 timeout = timeouts[TCP_CONNTRACK_CLOSE];
1138         else if ((ct->proto.tcp.seen[0].flags | ct->proto.tcp.seen[1].flags) &
1139                  IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED &&
1140                  timeouts[new_state] > timeouts[TCP_CONNTRACK_UNACK])
1141                 timeout = timeouts[TCP_CONNTRACK_UNACK];
1142         else if (ct->proto.tcp.last_win == 0 &&
1143                  timeouts[new_state] > timeouts[TCP_CONNTRACK_RETRANS])
1144                 timeout = timeouts[TCP_CONNTRACK_RETRANS];
1145         else
1146                 timeout = timeouts[new_state];
1147         spin_unlock_bh(&ct->lock);
1148
1149         if (new_state != old_state)
1150                 nf_conntrack_event_cache(IPCT_PROTOINFO, ct);
1151
1152         if (!test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
1153                 /* If only reply is a RST, we can consider ourselves not to
1154                    have an established connection: this is a fairly common
1155                    problem case, so we can delete the conntrack
1156                    immediately.  --RR */
1157                 if (th->rst) {
1158                         nf_ct_kill_acct(ct, ctinfo, skb);
1159                         return NF_ACCEPT;
1160                 }
1161
1162                 if (index == TCP_SYN_SET && old_state == TCP_CONNTRACK_SYN_SENT) {
1163                         /* do not renew timeout on SYN retransmit.
1164                          *
1165                          * Else port reuse by client or NAT middlebox can keep
1166                          * entry alive indefinitely (including nat info).
1167                          */
1168                         return NF_ACCEPT;
1169                 }
1170
1171                 /* ESTABLISHED without SEEN_REPLY, i.e. mid-connection
1172                  * pickup with loose=1. Avoid large ESTABLISHED timeout.
1173                  */
1174                 if (new_state == TCP_CONNTRACK_ESTABLISHED &&
1175                     timeout > timeouts[TCP_CONNTRACK_UNACK])
1176                         timeout = timeouts[TCP_CONNTRACK_UNACK];
1177         } else if (!test_bit(IPS_ASSURED_BIT, &ct->status)
1178                    && (old_state == TCP_CONNTRACK_SYN_RECV
1179                        || old_state == TCP_CONNTRACK_ESTABLISHED)
1180                    && new_state == TCP_CONNTRACK_ESTABLISHED) {
1181                 /* Set ASSURED if we see valid ack in ESTABLISHED
1182                    after SYN_RECV or a valid answer for a picked up
1183                    connection. */
1184                 set_bit(IPS_ASSURED_BIT, &ct->status);
1185                 nf_conntrack_event_cache(IPCT_ASSURED, ct);
1186         }
1187         nf_ct_refresh_acct(ct, ctinfo, skb, timeout);
1188
1189         return NF_ACCEPT;
1190 }
1191
1192 static bool tcp_can_early_drop(const struct nf_conn *ct)
1193 {
1194         switch (ct->proto.tcp.state) {
1195         case TCP_CONNTRACK_FIN_WAIT:
1196         case TCP_CONNTRACK_LAST_ACK:
1197         case TCP_CONNTRACK_TIME_WAIT:
1198         case TCP_CONNTRACK_CLOSE:
1199         case TCP_CONNTRACK_CLOSE_WAIT:
1200                 return true;
1201         default:
1202                 break;
1203         }
1204
1205         return false;
1206 }
1207
1208 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
1209
1210 #include <linux/netfilter/nfnetlink.h>
1211 #include <linux/netfilter/nfnetlink_conntrack.h>
1212
1213 static int tcp_to_nlattr(struct sk_buff *skb, struct nlattr *nla,
1214                          struct nf_conn *ct)
1215 {
1216         struct nlattr *nest_parms;
1217         struct nf_ct_tcp_flags tmp = {};
1218
1219         spin_lock_bh(&ct->lock);
1220         nest_parms = nla_nest_start(skb, CTA_PROTOINFO_TCP);
1221         if (!nest_parms)
1222                 goto nla_put_failure;
1223
1224         if (nla_put_u8(skb, CTA_PROTOINFO_TCP_STATE, ct->proto.tcp.state) ||
1225             nla_put_u8(skb, CTA_PROTOINFO_TCP_WSCALE_ORIGINAL,
1226                        ct->proto.tcp.seen[0].td_scale) ||
1227             nla_put_u8(skb, CTA_PROTOINFO_TCP_WSCALE_REPLY,
1228                        ct->proto.tcp.seen[1].td_scale))
1229                 goto nla_put_failure;
1230
1231         tmp.flags = ct->proto.tcp.seen[0].flags;
1232         if (nla_put(skb, CTA_PROTOINFO_TCP_FLAGS_ORIGINAL,
1233                     sizeof(struct nf_ct_tcp_flags), &tmp))
1234                 goto nla_put_failure;
1235
1236         tmp.flags = ct->proto.tcp.seen[1].flags;
1237         if (nla_put(skb, CTA_PROTOINFO_TCP_FLAGS_REPLY,
1238                     sizeof(struct nf_ct_tcp_flags), &tmp))
1239                 goto nla_put_failure;
1240         spin_unlock_bh(&ct->lock);
1241
1242         nla_nest_end(skb, nest_parms);
1243
1244         return 0;
1245
1246 nla_put_failure:
1247         spin_unlock_bh(&ct->lock);
1248         return -1;
1249 }
1250
1251 static const struct nla_policy tcp_nla_policy[CTA_PROTOINFO_TCP_MAX+1] = {
1252         [CTA_PROTOINFO_TCP_STATE]           = { .type = NLA_U8 },
1253         [CTA_PROTOINFO_TCP_WSCALE_ORIGINAL] = { .type = NLA_U8 },
1254         [CTA_PROTOINFO_TCP_WSCALE_REPLY]    = { .type = NLA_U8 },
1255         [CTA_PROTOINFO_TCP_FLAGS_ORIGINAL]  = { .len = sizeof(struct nf_ct_tcp_flags) },
1256         [CTA_PROTOINFO_TCP_FLAGS_REPLY]     = { .len = sizeof(struct nf_ct_tcp_flags) },
1257 };
1258
1259 #define TCP_NLATTR_SIZE ( \
1260         NLA_ALIGN(NLA_HDRLEN + 1) + \
1261         NLA_ALIGN(NLA_HDRLEN + 1) + \
1262         NLA_ALIGN(NLA_HDRLEN + sizeof(struct nf_ct_tcp_flags)) + \
1263         NLA_ALIGN(NLA_HDRLEN + sizeof(struct nf_ct_tcp_flags)))
1264
1265 static int nlattr_to_tcp(struct nlattr *cda[], struct nf_conn *ct)
1266 {
1267         struct nlattr *pattr = cda[CTA_PROTOINFO_TCP];
1268         struct nlattr *tb[CTA_PROTOINFO_TCP_MAX+1];
1269         int err;
1270
1271         /* updates could not contain anything about the private
1272          * protocol info, in that case skip the parsing */
1273         if (!pattr)
1274                 return 0;
1275
1276         err = nla_parse_nested_deprecated(tb, CTA_PROTOINFO_TCP_MAX, pattr,
1277                                           tcp_nla_policy, NULL);
1278         if (err < 0)
1279                 return err;
1280
1281         if (tb[CTA_PROTOINFO_TCP_STATE] &&
1282             nla_get_u8(tb[CTA_PROTOINFO_TCP_STATE]) >= TCP_CONNTRACK_MAX)
1283                 return -EINVAL;
1284
1285         spin_lock_bh(&ct->lock);
1286         if (tb[CTA_PROTOINFO_TCP_STATE])
1287                 ct->proto.tcp.state = nla_get_u8(tb[CTA_PROTOINFO_TCP_STATE]);
1288
1289         if (tb[CTA_PROTOINFO_TCP_FLAGS_ORIGINAL]) {
1290                 struct nf_ct_tcp_flags *attr =
1291                         nla_data(tb[CTA_PROTOINFO_TCP_FLAGS_ORIGINAL]);
1292                 ct->proto.tcp.seen[0].flags &= ~attr->mask;
1293                 ct->proto.tcp.seen[0].flags |= attr->flags & attr->mask;
1294         }
1295
1296         if (tb[CTA_PROTOINFO_TCP_FLAGS_REPLY]) {
1297                 struct nf_ct_tcp_flags *attr =
1298                         nla_data(tb[CTA_PROTOINFO_TCP_FLAGS_REPLY]);
1299                 ct->proto.tcp.seen[1].flags &= ~attr->mask;
1300                 ct->proto.tcp.seen[1].flags |= attr->flags & attr->mask;
1301         }
1302
1303         if (tb[CTA_PROTOINFO_TCP_WSCALE_ORIGINAL] &&
1304             tb[CTA_PROTOINFO_TCP_WSCALE_REPLY] &&
1305             ct->proto.tcp.seen[0].flags & IP_CT_TCP_FLAG_WINDOW_SCALE &&
1306             ct->proto.tcp.seen[1].flags & IP_CT_TCP_FLAG_WINDOW_SCALE) {
1307                 ct->proto.tcp.seen[0].td_scale =
1308                         nla_get_u8(tb[CTA_PROTOINFO_TCP_WSCALE_ORIGINAL]);
1309                 ct->proto.tcp.seen[1].td_scale =
1310                         nla_get_u8(tb[CTA_PROTOINFO_TCP_WSCALE_REPLY]);
1311         }
1312         spin_unlock_bh(&ct->lock);
1313
1314         return 0;
1315 }
1316
1317 static unsigned int tcp_nlattr_tuple_size(void)
1318 {
1319         static unsigned int size __read_mostly;
1320
1321         if (!size)
1322                 size = nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1);
1323
1324         return size;
1325 }
1326 #endif
1327
1328 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
1329
1330 #include <linux/netfilter/nfnetlink.h>
1331 #include <linux/netfilter/nfnetlink_cttimeout.h>
1332
1333 static int tcp_timeout_nlattr_to_obj(struct nlattr *tb[],
1334                                      struct net *net, void *data)
1335 {
1336         struct nf_tcp_net *tn = nf_tcp_pernet(net);
1337         unsigned int *timeouts = data;
1338         int i;
1339
1340         if (!timeouts)
1341                 timeouts = tn->timeouts;
1342         /* set default TCP timeouts. */
1343         for (i=0; i<TCP_CONNTRACK_TIMEOUT_MAX; i++)
1344                 timeouts[i] = tn->timeouts[i];
1345
1346         if (tb[CTA_TIMEOUT_TCP_SYN_SENT]) {
1347                 timeouts[TCP_CONNTRACK_SYN_SENT] =
1348                         ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_SYN_SENT]))*HZ;
1349         }
1350
1351         if (tb[CTA_TIMEOUT_TCP_SYN_RECV]) {
1352                 timeouts[TCP_CONNTRACK_SYN_RECV] =
1353                         ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_SYN_RECV]))*HZ;
1354         }
1355         if (tb[CTA_TIMEOUT_TCP_ESTABLISHED]) {
1356                 timeouts[TCP_CONNTRACK_ESTABLISHED] =
1357                         ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_ESTABLISHED]))*HZ;
1358         }
1359         if (tb[CTA_TIMEOUT_TCP_FIN_WAIT]) {
1360                 timeouts[TCP_CONNTRACK_FIN_WAIT] =
1361                         ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_FIN_WAIT]))*HZ;
1362         }
1363         if (tb[CTA_TIMEOUT_TCP_CLOSE_WAIT]) {
1364                 timeouts[TCP_CONNTRACK_CLOSE_WAIT] =
1365                         ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_CLOSE_WAIT]))*HZ;
1366         }
1367         if (tb[CTA_TIMEOUT_TCP_LAST_ACK]) {
1368                 timeouts[TCP_CONNTRACK_LAST_ACK] =
1369                         ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_LAST_ACK]))*HZ;
1370         }
1371         if (tb[CTA_TIMEOUT_TCP_TIME_WAIT]) {
1372                 timeouts[TCP_CONNTRACK_TIME_WAIT] =
1373                         ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_TIME_WAIT]))*HZ;
1374         }
1375         if (tb[CTA_TIMEOUT_TCP_CLOSE]) {
1376                 timeouts[TCP_CONNTRACK_CLOSE] =
1377                         ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_CLOSE]))*HZ;
1378         }
1379         if (tb[CTA_TIMEOUT_TCP_SYN_SENT2]) {
1380                 timeouts[TCP_CONNTRACK_SYN_SENT2] =
1381                         ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_SYN_SENT2]))*HZ;
1382         }
1383         if (tb[CTA_TIMEOUT_TCP_RETRANS]) {
1384                 timeouts[TCP_CONNTRACK_RETRANS] =
1385                         ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_RETRANS]))*HZ;
1386         }
1387         if (tb[CTA_TIMEOUT_TCP_UNACK]) {
1388                 timeouts[TCP_CONNTRACK_UNACK] =
1389                         ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_UNACK]))*HZ;
1390         }
1391
1392         timeouts[CTA_TIMEOUT_TCP_UNSPEC] = timeouts[CTA_TIMEOUT_TCP_SYN_SENT];
1393         return 0;
1394 }
1395
1396 static int
1397 tcp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
1398 {
1399         const unsigned int *timeouts = data;
1400
1401         if (nla_put_be32(skb, CTA_TIMEOUT_TCP_SYN_SENT,
1402                         htonl(timeouts[TCP_CONNTRACK_SYN_SENT] / HZ)) ||
1403             nla_put_be32(skb, CTA_TIMEOUT_TCP_SYN_RECV,
1404                          htonl(timeouts[TCP_CONNTRACK_SYN_RECV] / HZ)) ||
1405             nla_put_be32(skb, CTA_TIMEOUT_TCP_ESTABLISHED,
1406                          htonl(timeouts[TCP_CONNTRACK_ESTABLISHED] / HZ)) ||
1407             nla_put_be32(skb, CTA_TIMEOUT_TCP_FIN_WAIT,
1408                          htonl(timeouts[TCP_CONNTRACK_FIN_WAIT] / HZ)) ||
1409             nla_put_be32(skb, CTA_TIMEOUT_TCP_CLOSE_WAIT,
1410                          htonl(timeouts[TCP_CONNTRACK_CLOSE_WAIT] / HZ)) ||
1411             nla_put_be32(skb, CTA_TIMEOUT_TCP_LAST_ACK,
1412                          htonl(timeouts[TCP_CONNTRACK_LAST_ACK] / HZ)) ||
1413             nla_put_be32(skb, CTA_TIMEOUT_TCP_TIME_WAIT,
1414                          htonl(timeouts[TCP_CONNTRACK_TIME_WAIT] / HZ)) ||
1415             nla_put_be32(skb, CTA_TIMEOUT_TCP_CLOSE,
1416                          htonl(timeouts[TCP_CONNTRACK_CLOSE] / HZ)) ||
1417             nla_put_be32(skb, CTA_TIMEOUT_TCP_SYN_SENT2,
1418                          htonl(timeouts[TCP_CONNTRACK_SYN_SENT2] / HZ)) ||
1419             nla_put_be32(skb, CTA_TIMEOUT_TCP_RETRANS,
1420                          htonl(timeouts[TCP_CONNTRACK_RETRANS] / HZ)) ||
1421             nla_put_be32(skb, CTA_TIMEOUT_TCP_UNACK,
1422                          htonl(timeouts[TCP_CONNTRACK_UNACK] / HZ)))
1423                 goto nla_put_failure;
1424         return 0;
1425
1426 nla_put_failure:
1427         return -ENOSPC;
1428 }
1429
1430 static const struct nla_policy tcp_timeout_nla_policy[CTA_TIMEOUT_TCP_MAX+1] = {
1431         [CTA_TIMEOUT_TCP_SYN_SENT]      = { .type = NLA_U32 },
1432         [CTA_TIMEOUT_TCP_SYN_RECV]      = { .type = NLA_U32 },
1433         [CTA_TIMEOUT_TCP_ESTABLISHED]   = { .type = NLA_U32 },
1434         [CTA_TIMEOUT_TCP_FIN_WAIT]      = { .type = NLA_U32 },
1435         [CTA_TIMEOUT_TCP_CLOSE_WAIT]    = { .type = NLA_U32 },
1436         [CTA_TIMEOUT_TCP_LAST_ACK]      = { .type = NLA_U32 },
1437         [CTA_TIMEOUT_TCP_TIME_WAIT]     = { .type = NLA_U32 },
1438         [CTA_TIMEOUT_TCP_CLOSE]         = { .type = NLA_U32 },
1439         [CTA_TIMEOUT_TCP_SYN_SENT2]     = { .type = NLA_U32 },
1440         [CTA_TIMEOUT_TCP_RETRANS]       = { .type = NLA_U32 },
1441         [CTA_TIMEOUT_TCP_UNACK]         = { .type = NLA_U32 },
1442 };
1443 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
1444
1445 void nf_conntrack_tcp_init_net(struct net *net)
1446 {
1447         struct nf_tcp_net *tn = nf_tcp_pernet(net);
1448         int i;
1449
1450         for (i = 0; i < TCP_CONNTRACK_TIMEOUT_MAX; i++)
1451                 tn->timeouts[i] = tcp_timeouts[i];
1452
1453         /* timeouts[0] is unused, make it same as SYN_SENT so
1454          * ->timeouts[0] contains 'new' timeout, like udp or icmp.
1455          */
1456         tn->timeouts[0] = tcp_timeouts[TCP_CONNTRACK_SYN_SENT];
1457         tn->tcp_loose = nf_ct_tcp_loose;
1458         tn->tcp_be_liberal = nf_ct_tcp_be_liberal;
1459         tn->tcp_max_retrans = nf_ct_tcp_max_retrans;
1460 }
1461
1462 const struct nf_conntrack_l4proto nf_conntrack_l4proto_tcp =
1463 {
1464         .l4proto                = IPPROTO_TCP,
1465 #ifdef CONFIG_NF_CONNTRACK_PROCFS
1466         .print_conntrack        = tcp_print_conntrack,
1467 #endif
1468         .can_early_drop         = tcp_can_early_drop,
1469 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
1470         .to_nlattr              = tcp_to_nlattr,
1471         .from_nlattr            = nlattr_to_tcp,
1472         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
1473         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
1474         .nlattr_tuple_size      = tcp_nlattr_tuple_size,
1475         .nlattr_size            = TCP_NLATTR_SIZE,
1476         .nla_policy             = nf_ct_port_nla_policy,
1477 #endif
1478 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
1479         .ctnl_timeout           = {
1480                 .nlattr_to_obj  = tcp_timeout_nlattr_to_obj,
1481                 .obj_to_nlattr  = tcp_timeout_obj_to_nlattr,
1482                 .nlattr_max     = CTA_TIMEOUT_TCP_MAX,
1483                 .obj_size       = sizeof(unsigned int) *
1484                                         TCP_CONNTRACK_TIMEOUT_MAX,
1485                 .nla_policy     = tcp_timeout_nla_policy,
1486         },
1487 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
1488 };