net/netfilter/nf_conntrack_proto_tcp.c

   1 /* (C) 1999-2001 Paul `Rusty' Russell
   2  * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
   3  * (C) 2002-2013 Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
   4  * (C) 2006-2012 Patrick McHardy <kaber@trash.net>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/types.h>
  12 #include <linux/timer.h>
  13 #include <linux/module.h>
  14 #include <linux/in.h>
  15 #include <linux/tcp.h>
  16 #include <linux/spinlock.h>
  17 #include <linux/skbuff.h>
  18 #include <linux/ipv6.h>
  19 #include <net/ip6_checksum.h>
  20 #include <asm/unaligned.h>
  21
  22 #include <net/tcp.h>
  23
  24 #include <linux/netfilter.h>
  25 #include <linux/netfilter_ipv4.h>
  26 #include <linux/netfilter_ipv6.h>
  27 #include <net/netfilter/nf_conntrack.h>
  28 #include <net/netfilter/nf_conntrack_l4proto.h>
  29 #include <net/netfilter/nf_conntrack_ecache.h>
  30 #include <net/netfilter/nf_conntrack_seqadj.h>
  31 #include <net/netfilter/nf_conntrack_synproxy.h>
  32 #include <net/netfilter/nf_log.h>
  33 #include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
  34 #include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
  35
  36 /* "Be conservative in what you do,
  37     be liberal in what you accept from others."
  38     If it's non-zero, we mark only out of window RST segments as INVALID. */
  39 static int nf_ct_tcp_be_liberal __read_mostly = 0;
  40
  41 /* If it is set to zero, we disable picking up already established
  42    connections. */
  43 static int nf_ct_tcp_loose __read_mostly = 1;
  44
  45 /* Max number of the retransmitted packets without receiving an (acceptable)
  46    ACK from the destination. If this number is reached, a shorter timer
  47    will be started. */
  48 static int nf_ct_tcp_max_retrans __read_mostly = 3;
  49
  50   /* FIXME: Examine ipfilter's timeouts and conntrack transitions more
  51      closely.  They're more complex. --RR */
  52
  53 static const char *const tcp_conntrack_names[] = {
  54         "NONE",
  55         "SYN_SENT",
  56         "SYN_RECV",
  57         "ESTABLISHED",
  58         "FIN_WAIT",
  59         "CLOSE_WAIT",
  60         "LAST_ACK",
  61         "TIME_WAIT",
  62         "CLOSE",
  63         "SYN_SENT2",
  64 };
  65
  66 #define SECS * HZ
  67 #define MINS * 60 SECS
  68 #define HOURS * 60 MINS
  69 #define DAYS * 24 HOURS
  70
  71 static unsigned int tcp_timeouts[TCP_CONNTRACK_TIMEOUT_MAX] __read_mostly = {
  72         [TCP_CONNTRACK_SYN_SENT]        = 2 MINS,
  73         [TCP_CONNTRACK_SYN_RECV]        = 60 SECS,
  74         [TCP_CONNTRACK_ESTABLISHED]     = 5 DAYS,
  75         [TCP_CONNTRACK_FIN_WAIT]        = 2 MINS,
  76         [TCP_CONNTRACK_CLOSE_WAIT]      = 60 SECS,
  77         [TCP_CONNTRACK_LAST_ACK]        = 30 SECS,
  78         [TCP_CONNTRACK_TIME_WAIT]       = 2 MINS,
  79         [TCP_CONNTRACK_CLOSE]           = 10 SECS,
  80         [TCP_CONNTRACK_SYN_SENT2]       = 2 MINS,
  81 /* RFC1122 says the R2 limit should be at least 100 seconds.
  82    Linux uses 15 packets as limit, which corresponds
  83    to ~13-30min depending on RTO. */
  84         [TCP_CONNTRACK_RETRANS]         = 5 MINS,
  85         [TCP_CONNTRACK_UNACK]           = 5 MINS,
  86 };
  87
  88 #define sNO TCP_CONNTRACK_NONE
  89 #define sSS TCP_CONNTRACK_SYN_SENT
  90 #define sSR TCP_CONNTRACK_SYN_RECV
  91 #define sES TCP_CONNTRACK_ESTABLISHED
  92 #define sFW TCP_CONNTRACK_FIN_WAIT
  93 #define sCW TCP_CONNTRACK_CLOSE_WAIT
  94 #define sLA TCP_CONNTRACK_LAST_ACK
  95 #define sTW TCP_CONNTRACK_TIME_WAIT
  96 #define sCL TCP_CONNTRACK_CLOSE
  97 #define sS2 TCP_CONNTRACK_SYN_SENT2
  98 #define sIV TCP_CONNTRACK_MAX
  99 #define sIG TCP_CONNTRACK_IGNORE
 100
 101 /* What TCP flags are set from RST/SYN/FIN/ACK. */
 102 enum tcp_bit_set {
 103         TCP_SYN_SET,
 104         TCP_SYNACK_SET,
 105         TCP_FIN_SET,
 106         TCP_ACK_SET,
 107         TCP_RST_SET,
 108         TCP_NONE_SET,
 109 };
 110
 111 /*
 112  * The TCP state transition table needs a few words...
 113  *
 114  * We are the man in the middle. All the packets go through us
 115  * but might get lost in transit to the destination.
 116  * It is assumed that the destinations can't receive segments
 117  * we haven't seen.
 118  *
 119  * The checked segment is in window, but our windows are *not*
 120  * equivalent with the ones of the sender/receiver. We always
 121  * try to guess the state of the current sender.
 122  *
 123  * The meaning of the states are:
 124  *
 125  * NONE:        initial state
 126  * SYN_SENT:    SYN-only packet seen
 127  * SYN_SENT2:   SYN-only packet seen from reply dir, simultaneous open
 128  * SYN_RECV:    SYN-ACK packet seen
 129  * ESTABLISHED: ACK packet seen
 130  * FIN_WAIT:    FIN packet seen
 131  * CLOSE_WAIT:  ACK seen (after FIN)
 132  * LAST_ACK:    FIN seen (after FIN)
 133  * TIME_WAIT:   last ACK seen
 134  * CLOSE:       closed connection (RST)
 135  *
 136  * Packets marked as IGNORED (sIG):
 137  *      if they may be either invalid or valid
 138  *      and the receiver may send back a connection
 139  *      closing RST or a SYN/ACK.
 140  *
 141  * Packets marked as INVALID (sIV):
 142  *      if we regard them as truly invalid packets
 143  */
 144 static const u8 tcp_conntracks[2][6][TCP_CONNTRACK_MAX] = {
 145         {
 146 /* ORIGINAL */
 147 /*           sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2   */
 148 /*syn*/    { sSS, sSS, sIG, sIG, sIG, sIG, sIG, sSS, sSS, sS2 },
 149 /*
 150  *      sNO -> sSS      Initialize a new connection
 151  *      sSS -> sSS      Retransmitted SYN
 152  *      sS2 -> sS2      Late retransmitted SYN
 153  *      sSR -> sIG
 154  *      sES -> sIG      Error: SYNs in window outside the SYN_SENT state
 155  *                      are errors. Receiver will reply with RST
 156  *                      and close the connection.
 157  *                      Or we are not in sync and hold a dead connection.
 158  *      sFW -> sIG
 159  *      sCW -> sIG
 160  *      sLA -> sIG
 161  *      sTW -> sSS      Reopened connection (RFC 1122).
 162  *      sCL -> sSS
 163  */
 164 /*           sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2   */
 165 /*synack*/ { sIV, sIV, sSR, sIV, sIV, sIV, sIV, sIV, sIV, sSR },
 166 /*
 167  *      sNO -> sIV      Too late and no reason to do anything
 168  *      sSS -> sIV      Client can't send SYN and then SYN/ACK
 169  *      sS2 -> sSR      SYN/ACK sent to SYN2 in simultaneous open
 170  *      sSR -> sSR      Late retransmitted SYN/ACK in simultaneous open
 171  *      sES -> sIV      Invalid SYN/ACK packets sent by the client
 172  *      sFW -> sIV
 173  *      sCW -> sIV
 174  *      sLA -> sIV
 175  *      sTW -> sIV
 176  *      sCL -> sIV
 177  */
 178 /*           sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2   */
 179 /*fin*/    { sIV, sIV, sFW, sFW, sLA, sLA, sLA, sTW, sCL, sIV },
 180 /*
 181  *      sNO -> sIV      Too late and no reason to do anything...
 182  *      sSS -> sIV      Client migth not send FIN in this state:
 183  *                      we enforce waiting for a SYN/ACK reply first.
 184  *      sS2 -> sIV
 185  *      sSR -> sFW      Close started.
 186  *      sES -> sFW
 187  *      sFW -> sLA      FIN seen in both directions, waiting for
 188  *                      the last ACK.
 189  *                      Migth be a retransmitted FIN as well...
 190  *      sCW -> sLA
 191  *      sLA -> sLA      Retransmitted FIN. Remain in the same state.
 192  *      sTW -> sTW
 193  *      sCL -> sCL
 194  */
 195 /*           sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2   */
 196 /*ack*/    { sES, sIV, sES, sES, sCW, sCW, sTW, sTW, sCL, sIV },
 197 /*
 198  *      sNO -> sES      Assumed.
 199  *      sSS -> sIV      ACK is invalid: we haven't seen a SYN/ACK yet.
 200  *      sS2 -> sIV
 201  *      sSR -> sES      Established state is reached.
 202  *      sES -> sES      :-)
 203  *      sFW -> sCW      Normal close request answered by ACK.
 204  *      sCW -> sCW
 205  *      sLA -> sTW      Last ACK detected (RFC5961 challenged)
 206  *      sTW -> sTW      Retransmitted last ACK. Remain in the same state.
 207  *      sCL -> sCL
 208  */
 209 /*           sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2   */
 210 /*rst*/    { sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL },
 211 /*none*/   { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV }
 212         },
 213         {
 214 /* REPLY */
 215 /*           sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2   */
 216 /*syn*/    { sIV, sS2, sIV, sIV, sIV, sIV, sIV, sSS, sIV, sS2 },
 217 /*
 218  *      sNO -> sIV      Never reached.
 219  *      sSS -> sS2      Simultaneous open
 220  *      sS2 -> sS2      Retransmitted simultaneous SYN
 221  *      sSR -> sIV      Invalid SYN packets sent by the server
 222  *      sES -> sIV
 223  *      sFW -> sIV
 224  *      sCW -> sIV
 225  *      sLA -> sIV
 226  *      sTW -> sSS      Reopened connection, but server may have switched role
 227  *      sCL -> sIV
 228  */
 229 /*           sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2   */
 230 /*synack*/ { sIV, sSR, sIG, sIG, sIG, sIG, sIG, sIG, sIG, sSR },
 231 /*
 232  *      sSS -> sSR      Standard open.
 233  *      sS2 -> sSR      Simultaneous open
 234  *      sSR -> sIG      Retransmitted SYN/ACK, ignore it.
 235  *      sES -> sIG      Late retransmitted SYN/ACK?
 236  *      sFW -> sIG      Might be SYN/ACK answering ignored SYN
 237  *      sCW -> sIG
 238  *      sLA -> sIG
 239  *      sTW -> sIG
 240  *      sCL -> sIG
 241  */
 242 /*           sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2   */
 243 /*fin*/    { sIV, sIV, sFW, sFW, sLA, sLA, sLA, sTW, sCL, sIV },
 244 /*
 245  *      sSS -> sIV      Server might not send FIN in this state.
 246  *      sS2 -> sIV
 247  *      sSR -> sFW      Close started.
 248  *      sES -> sFW
 249  *      sFW -> sLA      FIN seen in both directions.
 250  *      sCW -> sLA
 251  *      sLA -> sLA      Retransmitted FIN.
 252  *      sTW -> sTW
 253  *      sCL -> sCL
 254  */
 255 /*           sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2   */
 256 /*ack*/    { sIV, sIG, sSR, sES, sCW, sCW, sTW, sTW, sCL, sIG },
 257 /*
 258  *      sSS -> sIG      Might be a half-open connection.
 259  *      sS2 -> sIG
 260  *      sSR -> sSR      Might answer late resent SYN.
 261  *      sES -> sES      :-)
 262  *      sFW -> sCW      Normal close request answered by ACK.
 263  *      sCW -> sCW
 264  *      sLA -> sTW      Last ACK detected (RFC5961 challenged)
 265  *      sTW -> sTW      Retransmitted last ACK.
 266  *      sCL -> sCL
 267  */
 268 /*           sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2   */
 269 /*rst*/    { sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL },
 270 /*none*/   { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV }
 271         }
 272 };
 273
 274 static inline struct nf_tcp_net *tcp_pernet(struct net *net)
 275 {
 276         return &net->ct.nf_ct_proto.tcp;
 277 }
 278
 279 static bool tcp_pkt_to_tuple(const struct sk_buff *skb, unsigned int dataoff,
 280                              struct net *net, struct nf_conntrack_tuple *tuple)
 281 {
 282         const struct tcphdr *hp;
 283         struct tcphdr _hdr;
 284
 285         /* Actually only need first 4 bytes to get ports. */
 286         hp = skb_header_pointer(skb, dataoff, 4, &_hdr);
 287         if (hp == NULL)
 288                 return false;
 289
 290         tuple->src.u.tcp.port = hp->source;
 291         tuple->dst.u.tcp.port = hp->dest;
 292
 293         return true;
 294 }
 295
 296 static bool tcp_invert_tuple(struct nf_conntrack_tuple *tuple,
 297                              const struct nf_conntrack_tuple *orig)
 298 {
 299         tuple->src.u.tcp.port = orig->dst.u.tcp.port;
 300         tuple->dst.u.tcp.port = orig->src.u.tcp.port;
 301         return true;
 302 }
 303
 304 /* Print out the per-protocol part of the tuple. */
 305 static void tcp_print_tuple(struct seq_file *s,
 306                             const struct nf_conntrack_tuple *tuple)
 307 {
 308         seq_printf(s, "sport=%hu dport=%hu ",
 309                    ntohs(tuple->src.u.tcp.port),
 310                    ntohs(tuple->dst.u.tcp.port));
 311 }
 312
 313 /* Print out the private part of the conntrack. */
 314 static void tcp_print_conntrack(struct seq_file *s, struct nf_conn *ct)
 315 {
 316         seq_printf(s, "%s ", tcp_conntrack_names[ct->proto.tcp.state]);
 317 }
 318
 319 static unsigned int get_conntrack_index(const struct tcphdr *tcph)
 320 {
 321         if (tcph->rst) return TCP_RST_SET;
 322         else if (tcph->syn) return (tcph->ack ? TCP_SYNACK_SET : TCP_SYN_SET);
 323         else if (tcph->fin) return TCP_FIN_SET;
 324         else if (tcph->ack) return TCP_ACK_SET;
 325         else return TCP_NONE_SET;
 326 }
 327
 328 /* TCP connection tracking based on 'Real Stateful TCP Packet Filtering
 329    in IP Filter' by Guido van Rooij.
 330
 331    http://www.sane.nl/events/sane2000/papers.html
 332    http://www.darkart.com/mirrors/www.obfuscation.org/ipf/
 333
 334    The boundaries and the conditions are changed according to RFC793:
 335    the packet must intersect the window (i.e. segments may be
 336    after the right or before the left edge) and thus receivers may ACK
 337    segments after the right edge of the window.
 338
 339         td_maxend = max(sack + max(win,1)) seen in reply packets
 340         td_maxwin = max(max(win, 1)) + (sack - ack) seen in sent packets
 341         td_maxwin += seq + len - sender.td_maxend
 342                         if seq + len > sender.td_maxend
 343         td_end    = max(seq + len) seen in sent packets
 344
 345    I.   Upper bound for valid data:     seq <= sender.td_maxend
 346    II.  Lower bound for valid data:     seq + len >= sender.td_end - receiver.td_maxwin
 347    III. Upper bound for valid (s)ack:   sack <= receiver.td_end
 348    IV.  Lower bound for valid (s)ack:   sack >= receiver.td_end - MAXACKWINDOW
 349
 350    where sack is the highest right edge of sack block found in the packet
 351    or ack in the case of packet without SACK option.
 352
 353    The upper bound limit for a valid (s)ack is not ignored -
 354    we doesn't have to deal with fragments.
 355 */
 356
 357 static inline __u32 segment_seq_plus_len(__u32 seq,
 358                                          size_t len,
 359                                          unsigned int dataoff,
 360                                          const struct tcphdr *tcph)
 361 {
 362         /* XXX Should I use payload length field in IP/IPv6 header ?
 363          * - YK */
 364         return (seq + len - dataoff - tcph->doff*4
 365                 + (tcph->syn ? 1 : 0) + (tcph->fin ? 1 : 0));
 366 }
 367
 368 /* Fixme: what about big packets? */
 369 #define MAXACKWINCONST                  66000
 370 #define MAXACKWINDOW(sender)                                            \
 371         ((sender)->td_maxwin > MAXACKWINCONST ? (sender)->td_maxwin     \
 372                                               : MAXACKWINCONST)
 373
 374 /*
 375  * Simplified tcp_parse_options routine from tcp_input.c
 376  */
 377 static void tcp_options(const struct sk_buff *skb,
 378                         unsigned int dataoff,
 379                         const struct tcphdr *tcph,
 380                         struct ip_ct_tcp_state *state)
 381 {
 382         unsigned char buff[(15 * 4) - sizeof(struct tcphdr)];
 383         const unsigned char *ptr;
 384         int length = (tcph->doff*4) - sizeof(struct tcphdr);
 385
 386         if (!length)
 387                 return;
 388
 389         ptr = skb_header_pointer(skb, dataoff + sizeof(struct tcphdr),
 390                                  length, buff);
 391         BUG_ON(ptr == NULL);
 392
 393         state->td_scale = 0;
 394         state->flags &= IP_CT_TCP_FLAG_BE_LIBERAL;
 395
 396         while (length > 0) {
 397                 int opcode=*ptr++;
 398                 int opsize;
 399
 400                 switch (opcode) {
 401                 case TCPOPT_EOL:
 402                         return;
 403                 case TCPOPT_NOP:        /* Ref: RFC 793 section 3.1 */
 404                         length--;
 405                         continue;
 406                 default:
 407                         if (length < 2)
 408                                 return;
 409                         opsize=*ptr++;
 410                         if (opsize < 2) /* "silly options" */
 411                                 return;
 412                         if (opsize > length)
 413                                 return; /* don't parse partial options */
 414
 415                         if (opcode == TCPOPT_SACK_PERM
 416                             && opsize == TCPOLEN_SACK_PERM)
 417                                 state->flags |= IP_CT_TCP_FLAG_SACK_PERM;
 418                         else if (opcode == TCPOPT_WINDOW
 419                                  && opsize == TCPOLEN_WINDOW) {
 420                                 state->td_scale = *(u_int8_t *)ptr;
 421
 422                                 if (state->td_scale > 14) {
 423                                         /* See RFC1323 */
 424                                         state->td_scale = 14;
 425                                 }
 426                                 state->flags |=
 427                                         IP_CT_TCP_FLAG_WINDOW_SCALE;
 428                         }
 429                         ptr += opsize - 2;
 430                         length -= opsize;
 431                 }
 432         }
 433 }
 434
 435 static void tcp_sack(const struct sk_buff *skb, unsigned int dataoff,
 436                      const struct tcphdr *tcph, __u32 *sack)
 437 {
 438         unsigned char buff[(15 * 4) - sizeof(struct tcphdr)];
 439         const unsigned char *ptr;
 440         int length = (tcph->doff*4) - sizeof(struct tcphdr);
 441         __u32 tmp;
 442
 443         if (!length)
 444                 return;
 445
 446         ptr = skb_header_pointer(skb, dataoff + sizeof(struct tcphdr),
 447                                  length, buff);
 448         BUG_ON(ptr == NULL);
 449
 450         /* Fast path for timestamp-only option */
 451         if (length == TCPOLEN_TSTAMP_ALIGNED
 452             && *(__be32 *)ptr == htonl((TCPOPT_NOP << 24)
 453                                        | (TCPOPT_NOP << 16)
 454                                        | (TCPOPT_TIMESTAMP << 8)
 455                                        | TCPOLEN_TIMESTAMP))
 456                 return;
 457
 458         while (length > 0) {
 459                 int opcode = *ptr++;
 460                 int opsize, i;
 461
 462                 switch (opcode) {
 463                 case TCPOPT_EOL:
 464                         return;
 465                 case TCPOPT_NOP:        /* Ref: RFC 793 section 3.1 */
 466                         length--;
 467                         continue;
 468                 default:
 469                         if (length < 2)
 470                                 return;
 471                         opsize = *ptr++;
 472                         if (opsize < 2) /* "silly options" */
 473                                 return;
 474                         if (opsize > length)
 475                                 return; /* don't parse partial options */
 476
 477                         if (opcode == TCPOPT_SACK
 478                             && opsize >= (TCPOLEN_SACK_BASE
 479                                           + TCPOLEN_SACK_PERBLOCK)
 480                             && !((opsize - TCPOLEN_SACK_BASE)
 481                                  % TCPOLEN_SACK_PERBLOCK)) {
 482                                 for (i = 0;
 483                                      i < (opsize - TCPOLEN_SACK_BASE);
 484                                      i += TCPOLEN_SACK_PERBLOCK) {
 485                                         tmp = get_unaligned_be32((__be32 *)(ptr+i)+1);
 486
 487                                         if (after(tmp, *sack))
 488                                                 *sack = tmp;
 489                                 }
 490                                 return;
 491                         }
 492                         ptr += opsize - 2;
 493                         length -= opsize;
 494                 }
 495         }
 496 }
 497
 498 static bool tcp_in_window(const struct nf_conn *ct,
 499                           struct ip_ct_tcp *state,
 500                           enum ip_conntrack_dir dir,
 501                           unsigned int index,
 502                           const struct sk_buff *skb,
 503                           unsigned int dataoff,
 504                           const struct tcphdr *tcph,
 505                           u_int8_t pf)
 506 {
 507         struct net *net = nf_ct_net(ct);
 508         struct nf_tcp_net *tn = tcp_pernet(net);
 509         struct ip_ct_tcp_state *sender = &state->seen[dir];
 510         struct ip_ct_tcp_state *receiver = &state->seen[!dir];
 511         const struct nf_conntrack_tuple *tuple = &ct->tuplehash[dir].tuple;
 512         __u32 seq, ack, sack, end, win, swin;
 513         s32 receiver_offset;
 514         bool res, in_recv_win;
 515
 516         /*
 517          * Get the required data from the packet.
 518          */
 519         seq = ntohl(tcph->seq);
 520         ack = sack = ntohl(tcph->ack_seq);
 521         win = ntohs(tcph->window);
 522         end = segment_seq_plus_len(seq, skb->len, dataoff, tcph);
 523
 524         if (receiver->flags & IP_CT_TCP_FLAG_SACK_PERM)
 525                 tcp_sack(skb, dataoff, tcph, &sack);
 526
 527         /* Take into account NAT sequence number mangling */
 528         receiver_offset = nf_ct_seq_offset(ct, !dir, ack - 1);
 529         ack -= receiver_offset;
 530         sack -= receiver_offset;
 531
 532         pr_debug("tcp_in_window: START\n");
 533         pr_debug("tcp_in_window: ");
 534         nf_ct_dump_tuple(tuple);
 535         pr_debug("seq=%u ack=%u+(%d) sack=%u+(%d) win=%u end=%u\n",
 536                  seq, ack, receiver_offset, sack, receiver_offset, win, end);
 537         pr_debug("tcp_in_window: sender end=%u maxend=%u maxwin=%u scale=%i "
 538                  "receiver end=%u maxend=%u maxwin=%u scale=%i\n",
 539                  sender->td_end, sender->td_maxend, sender->td_maxwin,
 540                  sender->td_scale,
 541                  receiver->td_end, receiver->td_maxend, receiver->td_maxwin,
 542                  receiver->td_scale);
 543
 544         if (sender->td_maxwin == 0) {
 545                 /*
 546                  * Initialize sender data.
 547                  */
 548                 if (tcph->syn) {
 549                         /*
 550                          * SYN-ACK in reply to a SYN
 551                          * or SYN from reply direction in simultaneous open.
 552                          */
 553                         sender->td_end =
 554                         sender->td_maxend = end;
 555                         sender->td_maxwin = (win == 0 ? 1 : win);
 556
 557                         tcp_options(skb, dataoff, tcph, sender);
 558                         /*
 559                          * RFC 1323:
 560                          * Both sides must send the Window Scale option
 561                          * to enable window scaling in either direction.
 562                          */
 563                         if (!(sender->flags & IP_CT_TCP_FLAG_WINDOW_SCALE
 564                               && receiver->flags & IP_CT_TCP_FLAG_WINDOW_SCALE))
 565                                 sender->td_scale =
 566                                 receiver->td_scale = 0;
 567                         if (!tcph->ack)
 568                                 /* Simultaneous open */
 569                                 return true;
 570                 } else {
 571                         /*
 572                          * We are in the middle of a connection,
 573                          * its history is lost for us.
 574                          * Let's try to use the data from the packet.
 575                          */
 576                         sender->td_end = end;
 577                         swin = win << sender->td_scale;
 578                         sender->td_maxwin = (swin == 0 ? 1 : swin);
 579                         sender->td_maxend = end + sender->td_maxwin;
 580                         /*
 581                          * We haven't seen traffic in the other direction yet
 582                          * but we have to tweak window tracking to pass III
 583                          * and IV until that happens.
 584                          */
 585                         if (receiver->td_maxwin == 0)
 586                                 receiver->td_end = receiver->td_maxend = sack;
 587                 }
 588         } else if (((state->state == TCP_CONNTRACK_SYN_SENT
 589                      && dir == IP_CT_DIR_ORIGINAL)
 590                    || (state->state == TCP_CONNTRACK_SYN_RECV
 591                      && dir == IP_CT_DIR_REPLY))
 592                    && after(end, sender->td_end)) {
 593                 /*
 594                  * RFC 793: "if a TCP is reinitialized ... then it need
 595                  * not wait at all; it must only be sure to use sequence
 596                  * numbers larger than those recently used."
 597                  */
 598                 sender->td_end =
 599                 sender->td_maxend = end;
 600                 sender->td_maxwin = (win == 0 ? 1 : win);
 601
 602                 tcp_options(skb, dataoff, tcph, sender);
 603         }
 604
 605         if (!(tcph->ack)) {
 606                 /*
 607                  * If there is no ACK, just pretend it was set and OK.
 608                  */
 609                 ack = sack = receiver->td_end;
 610         } else if (((tcp_flag_word(tcph) & (TCP_FLAG_ACK|TCP_FLAG_RST)) ==
 611                     (TCP_FLAG_ACK|TCP_FLAG_RST))
 612                    && (ack == 0)) {
 613                 /*
 614                  * Broken TCP stacks, that set ACK in RST packets as well
 615                  * with zero ack value.
 616                  */
 617                 ack = sack = receiver->td_end;
 618         }
 619
 620         if (tcph->rst && seq == 0 && state->state == TCP_CONNTRACK_SYN_SENT)
 621                 /*
 622                  * RST sent answering SYN.
 623                  */
 624                 seq = end = sender->td_end;
 625
 626         pr_debug("tcp_in_window: ");
 627         nf_ct_dump_tuple(tuple);
 628         pr_debug("seq=%u ack=%u+(%d) sack=%u+(%d) win=%u end=%u\n",
 629                  seq, ack, receiver_offset, sack, receiver_offset, win, end);
 630         pr_debug("tcp_in_window: sender end=%u maxend=%u maxwin=%u scale=%i "
 631                  "receiver end=%u maxend=%u maxwin=%u scale=%i\n",
 632                  sender->td_end, sender->td_maxend, sender->td_maxwin,
 633                  sender->td_scale,
 634                  receiver->td_end, receiver->td_maxend, receiver->td_maxwin,
 635                  receiver->td_scale);
 636
 637         /* Is the ending sequence in the receive window (if available)? */
 638         in_recv_win = !receiver->td_maxwin ||
 639                       after(end, sender->td_end - receiver->td_maxwin - 1);
 640
 641         pr_debug("tcp_in_window: I=%i II=%i III=%i IV=%i\n",
 642                  before(seq, sender->td_maxend + 1),
 643                  (in_recv_win ? 1 : 0),
 644                  before(sack, receiver->td_end + 1),
 645                  after(sack, receiver->td_end - MAXACKWINDOW(sender) - 1));
 646
 647         if (before(seq, sender->td_maxend + 1) &&
 648             in_recv_win &&
 649             before(sack, receiver->td_end + 1) &&
 650             after(sack, receiver->td_end - MAXACKWINDOW(sender) - 1)) {
 651                 /*
 652                  * Take into account window scaling (RFC 1323).
 653                  */
 654                 if (!tcph->syn)
 655                         win <<= sender->td_scale;
 656
 657                 /*
 658                  * Update sender data.
 659                  */
 660                 swin = win + (sack - ack);
 661                 if (sender->td_maxwin < swin)
 662                         sender->td_maxwin = swin;
 663                 if (after(end, sender->td_end)) {
 664                         sender->td_end = end;
 665                         sender->flags |= IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED;
 666                 }
 667                 if (tcph->ack) {
 668                         if (!(sender->flags & IP_CT_TCP_FLAG_MAXACK_SET)) {
 669                                 sender->td_maxack = ack;
 670                                 sender->flags |= IP_CT_TCP_FLAG_MAXACK_SET;
 671                         } else if (after(ack, sender->td_maxack))
 672                                 sender->td_maxack = ack;
 673                 }
 674
 675                 /*
 676                  * Update receiver data.
 677                  */
 678                 if (receiver->td_maxwin != 0 && after(end, sender->td_maxend))
 679                         receiver->td_maxwin += end - sender->td_maxend;
 680                 if (after(sack + win, receiver->td_maxend - 1)) {
 681                         receiver->td_maxend = sack + win;
 682                         if (win == 0)
 683                                 receiver->td_maxend++;
 684                 }
 685                 if (ack == receiver->td_end)
 686                         receiver->flags &= ~IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED;
 687
 688                 /*
 689                  * Check retransmissions.
 690                  */
 691                 if (index == TCP_ACK_SET) {
 692                         if (state->last_dir == dir
 693                             && state->last_seq == seq
 694                             && state->last_ack == ack
 695                             && state->last_end == end
 696                             && state->last_win == win)
 697                                 state->retrans++;
 698                         else {
 699                                 state->last_dir = dir;
 700                                 state->last_seq = seq;
 701                                 state->last_ack = ack;
 702                                 state->last_end = end;
 703                                 state->last_win = win;
 704                                 state->retrans = 0;
 705                         }
 706                 }
 707                 res = true;
 708         } else {
 709                 res = false;
 710                 if (sender->flags & IP_CT_TCP_FLAG_BE_LIBERAL ||
 711                     tn->tcp_be_liberal)
 712                         res = true;
 713                 if (!res && LOG_INVALID(net, IPPROTO_TCP))
 714                         nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
 715                         "nf_ct_tcp: %s ",
 716                         before(seq, sender->td_maxend + 1) ?
 717                         in_recv_win ?
 718                         before(sack, receiver->td_end + 1) ?
 719                         after(sack, receiver->td_end - MAXACKWINDOW(sender) - 1) ? "BUG"
 720                         : "ACK is under the lower bound (possible overly delayed ACK)"
 721                         : "ACK is over the upper bound (ACKed data not seen yet)"
 722                         : "SEQ is under the lower bound (already ACKed data retransmitted)"
 723                         : "SEQ is over the upper bound (over the window of the receiver)");
 724         }
 725
 726         pr_debug("tcp_in_window: res=%u sender end=%u maxend=%u maxwin=%u "
 727                  "receiver end=%u maxend=%u maxwin=%u\n",
 728                  res, sender->td_end, sender->td_maxend, sender->td_maxwin,
 729                  receiver->td_end, receiver->td_maxend, receiver->td_maxwin);
 730
 731         return res;
 732 }
 733
 734 /* table of valid flag combinations - PUSH, ECE and CWR are always valid */
 735 static const u8 tcp_valid_flags[(TCPHDR_FIN|TCPHDR_SYN|TCPHDR_RST|TCPHDR_ACK|
 736                                  TCPHDR_URG) + 1] =
 737 {
 738         [TCPHDR_SYN]                            = 1,
 739         [TCPHDR_SYN|TCPHDR_URG]                 = 1,
 740         [TCPHDR_SYN|TCPHDR_ACK]                 = 1,
 741         [TCPHDR_RST]                            = 1,
 742         [TCPHDR_RST|TCPHDR_ACK]                 = 1,
 743         [TCPHDR_FIN|TCPHDR_ACK]                 = 1,
 744         [TCPHDR_FIN|TCPHDR_ACK|TCPHDR_URG]      = 1,
 745         [TCPHDR_ACK]                            = 1,
 746         [TCPHDR_ACK|TCPHDR_URG]                 = 1,
 747 };
 748
 749 /* Protect conntrack agaist broken packets. Code taken from ipt_unclean.c.  */
 750 static int tcp_error(struct net *net, struct nf_conn *tmpl,
 751                      struct sk_buff *skb,
 752                      unsigned int dataoff,
 753                      enum ip_conntrack_info *ctinfo,
 754                      u_int8_t pf,
 755                      unsigned int hooknum)
 756 {
 757         const struct tcphdr *th;
 758         struct tcphdr _tcph;
 759         unsigned int tcplen = skb->len - dataoff;
 760         u_int8_t tcpflags;
 761
 762         /* Smaller that minimal TCP header? */
 763         th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph);
 764         if (th == NULL) {
 765                 if (LOG_INVALID(net, IPPROTO_TCP))
 766                         nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
 767                                 "nf_ct_tcp: short packet ");
 768                 return -NF_ACCEPT;
 769         }
 770
 771         /* Not whole TCP header or malformed packet */
 772         if (th->doff*4 < sizeof(struct tcphdr) || tcplen < th->doff*4) {
 773                 if (LOG_INVALID(net, IPPROTO_TCP))
 774                         nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
 775                                 "nf_ct_tcp: truncated/malformed packet ");
 776                 return -NF_ACCEPT;
 777         }
 778
 779         /* Checksum invalid? Ignore.
 780          * We skip checking packets on the outgoing path
 781          * because the checksum is assumed to be correct.
 782          */
 783         /* FIXME: Source route IP option packets --RR */
 784         if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
 785             nf_checksum(skb, hooknum, dataoff, IPPROTO_TCP, pf)) {
 786                 if (LOG_INVALID(net, IPPROTO_TCP))
 787                         nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
 788                                   "nf_ct_tcp: bad TCP checksum ");
 789                 return -NF_ACCEPT;
 790         }
 791
 792         /* Check TCP flags. */
 793         tcpflags = (tcp_flag_byte(th) & ~(TCPHDR_ECE|TCPHDR_CWR|TCPHDR_PSH));
 794         if (!tcp_valid_flags[tcpflags]) {
 795                 if (LOG_INVALID(net, IPPROTO_TCP))
 796                         nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
 797                                   "nf_ct_tcp: invalid TCP flag combination ");
 798                 return -NF_ACCEPT;
 799         }
 800
 801         return NF_ACCEPT;
 802 }
 803
 804 static unsigned int *tcp_get_timeouts(struct net *net)
 805 {
 806         return tcp_pernet(net)->timeouts;
 807 }
 808
 809 static void nf_ct_tcp_state_reset(struct ip_ct_tcp_state *state)
 810 {
 811         state->td_end           = 0;
 812         state->td_maxend        = 0;
 813         state->td_maxwin        = 0;
 814         state->td_maxack        = 0;
 815         state->td_scale         = 0;
 816         state->flags            &= IP_CT_TCP_FLAG_BE_LIBERAL;
 817 }
 818
 819 /* Returns verdict for packet, or -1 for invalid. */
 820 static int tcp_packet(struct nf_conn *ct,
 821                       const struct sk_buff *skb,
 822                       unsigned int dataoff,
 823                       enum ip_conntrack_info ctinfo,
 824                       u_int8_t pf,
 825                       unsigned int hooknum,
 826                       unsigned int *timeouts)
 827 {
 828         struct net *net = nf_ct_net(ct);
 829         struct nf_tcp_net *tn = tcp_pernet(net);
 830         struct nf_conntrack_tuple *tuple;
 831         enum tcp_conntrack new_state, old_state;
 832         enum ip_conntrack_dir dir;
 833         const struct tcphdr *th;
 834         struct tcphdr _tcph;
 835         unsigned long timeout;
 836         unsigned int index;
 837
 838         th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph);
 839         BUG_ON(th == NULL);
 840
 841         spin_lock_bh(&ct->lock);
 842         old_state = ct->proto.tcp.state;
 843         dir = CTINFO2DIR(ctinfo);
 844         index = get_conntrack_index(th);
 845         new_state = tcp_conntracks[dir][index][old_state];
 846         tuple = &ct->tuplehash[dir].tuple;
 847
 848         switch (new_state) {
 849         case TCP_CONNTRACK_SYN_SENT:
 850                 if (old_state < TCP_CONNTRACK_TIME_WAIT)
 851                         break;
 852                 /* RFC 1122: "When a connection is closed actively,
 853                  * it MUST linger in TIME-WAIT state for a time 2xMSL
 854                  * (Maximum Segment Lifetime). However, it MAY accept
 855                  * a new SYN from the remote TCP to reopen the connection
 856                  * directly from TIME-WAIT state, if..."
 857                  * We ignore the conditions because we are in the
 858                  * TIME-WAIT state anyway.
 859                  *
 860                  * Handle aborted connections: we and the server
 861                  * think there is an existing connection but the client
 862                  * aborts it and starts a new one.
 863                  */
 864                 if (((ct->proto.tcp.seen[dir].flags
 865                       | ct->proto.tcp.seen[!dir].flags)
 866                      & IP_CT_TCP_FLAG_CLOSE_INIT)
 867                     || (ct->proto.tcp.last_dir == dir
 868                         && ct->proto.tcp.last_index == TCP_RST_SET)) {
 869                         /* Attempt to reopen a closed/aborted connection.
 870                          * Delete this connection and look up again. */
 871                         spin_unlock_bh(&ct->lock);
 872
 873                         /* Only repeat if we can actually remove the timer.
 874                          * Destruction may already be in progress in process
 875                          * context and we must give it a chance to terminate.
 876                          */
 877                         if (nf_ct_kill(ct))
 878                                 return -NF_REPEAT;
 879                         return NF_DROP;
 880                 }
 881                 /* Fall through */
 882         case TCP_CONNTRACK_IGNORE:
 883                 /* Ignored packets:
 884                  *
 885                  * Our connection entry may be out of sync, so ignore
 886                  * packets which may signal the real connection between
 887                  * the client and the server.
 888                  *
 889                  * a) SYN in ORIGINAL
 890                  * b) SYN/ACK in REPLY
 891                  * c) ACK in reply direction after initial SYN in original.
 892                  *
 893                  * If the ignored packet is invalid, the receiver will send
 894                  * a RST we'll catch below.
 895                  */
 896                 if (index == TCP_SYNACK_SET
 897                     && ct->proto.tcp.last_index == TCP_SYN_SET
 898                     && ct->proto.tcp.last_dir != dir
 899                     && ntohl(th->ack_seq) == ct->proto.tcp.last_end) {
 900                         /* b) This SYN/ACK acknowledges a SYN that we earlier
 901                          * ignored as invalid. This means that the client and
 902                          * the server are both in sync, while the firewall is
 903                          * not. We get in sync from the previously annotated
 904                          * values.
 905                          */
 906                         old_state = TCP_CONNTRACK_SYN_SENT;
 907                         new_state = TCP_CONNTRACK_SYN_RECV;
 908                         ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_end =
 909                                 ct->proto.tcp.last_end;
 910                         ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_maxend =
 911                                 ct->proto.tcp.last_end;
 912                         ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_maxwin =
 913                                 ct->proto.tcp.last_win == 0 ?
 914                                         1 : ct->proto.tcp.last_win;
 915                         ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_scale =
 916                                 ct->proto.tcp.last_wscale;
 917                         ct->proto.tcp.last_flags &= ~IP_CT_EXP_CHALLENGE_ACK;
 918                         ct->proto.tcp.seen[ct->proto.tcp.last_dir].flags =
 919                                 ct->proto.tcp.last_flags;
 920                         nf_ct_tcp_state_reset(&ct->proto.tcp.seen[dir]);
 921                         break;
 922                 }
 923                 ct->proto.tcp.last_index = index;
 924                 ct->proto.tcp.last_dir = dir;
 925                 ct->proto.tcp.last_seq = ntohl(th->seq);
 926                 ct->proto.tcp.last_end =
 927                     segment_seq_plus_len(ntohl(th->seq), skb->len, dataoff, th);
 928                 ct->proto.tcp.last_win = ntohs(th->window);
 929
 930                 /* a) This is a SYN in ORIGINAL. The client and the server
 931                  * may be in sync but we are not. In that case, we annotate
 932                  * the TCP options and let the packet go through. If it is a
 933                  * valid SYN packet, the server will reply with a SYN/ACK, and
 934                  * then we'll get in sync. Otherwise, the server potentially
 935                  * responds with a challenge ACK if implementing RFC5961.
 936                  */
 937                 if (index == TCP_SYN_SET && dir == IP_CT_DIR_ORIGINAL) {
 938                         struct ip_ct_tcp_state seen = {};
 939
 940                         ct->proto.tcp.last_flags =
 941                         ct->proto.tcp.last_wscale = 0;
 942                         tcp_options(skb, dataoff, th, &seen);
 943                         if (seen.flags & IP_CT_TCP_FLAG_WINDOW_SCALE) {
 944                                 ct->proto.tcp.last_flags |=
 945                                         IP_CT_TCP_FLAG_WINDOW_SCALE;
 946                                 ct->proto.tcp.last_wscale = seen.td_scale;
 947                         }
 948                         if (seen.flags & IP_CT_TCP_FLAG_SACK_PERM) {
 949                                 ct->proto.tcp.last_flags |=
 950                                         IP_CT_TCP_FLAG_SACK_PERM;
 951                         }
 952                         /* Mark the potential for RFC5961 challenge ACK,
 953                          * this pose a special problem for LAST_ACK state
 954                          * as ACK is intrepretated as ACKing last FIN.
 955                          */
 956                         if (old_state == TCP_CONNTRACK_LAST_ACK)
 957                                 ct->proto.tcp.last_flags |=
 958                                         IP_CT_EXP_CHALLENGE_ACK;
 959                 }
 960                 spin_unlock_bh(&ct->lock);
 961                 if (LOG_INVALID(net, IPPROTO_TCP))
 962                         nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
 963                                   "nf_ct_tcp: invalid packet ignored in "
 964                                   "state %s ", tcp_conntrack_names[old_state]);
 965                 return NF_ACCEPT;
 966         case TCP_CONNTRACK_MAX:
 967                 /* Special case for SYN proxy: when the SYN to the server or
 968                  * the SYN/ACK from the server is lost, the client may transmit
 969                  * a keep-alive packet while in SYN_SENT state. This needs to
 970                  * be associated with the original conntrack entry in order to
 971                  * generate a new SYN with the correct sequence number.
 972                  */
 973                 if (nfct_synproxy(ct) && old_state == TCP_CONNTRACK_SYN_SENT &&
 974                     index == TCP_ACK_SET && dir == IP_CT_DIR_ORIGINAL &&
 975                     ct->proto.tcp.last_dir == IP_CT_DIR_ORIGINAL &&
 976                     ct->proto.tcp.seen[dir].td_end - 1 == ntohl(th->seq)) {
 977                         pr_debug("nf_ct_tcp: SYN proxy client keep alive\n");
 978                         spin_unlock_bh(&ct->lock);
 979                         return NF_ACCEPT;
 980                 }
 981
 982                 /* Invalid packet */
 983                 pr_debug("nf_ct_tcp: Invalid dir=%i index=%u ostate=%u\n",
 984                          dir, get_conntrack_index(th), old_state);
 985                 spin_unlock_bh(&ct->lock);
 986                 if (LOG_INVALID(net, IPPROTO_TCP))
 987                         nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
 988                                   "nf_ct_tcp: invalid state ");
 989                 return -NF_ACCEPT;
 990         case TCP_CONNTRACK_TIME_WAIT:
 991                 /* RFC5961 compliance cause stack to send "challenge-ACK"
 992                  * e.g. in response to spurious SYNs.  Conntrack MUST
 993                  * not believe this ACK is acking last FIN.
 994                  */
 995                 if (old_state == TCP_CONNTRACK_LAST_ACK &&
 996                     index == TCP_ACK_SET &&
 997                     ct->proto.tcp.last_dir != dir &&
 998                     ct->proto.tcp.last_index == TCP_SYN_SET &&
 999                     (ct->proto.tcp.last_flags & IP_CT_EXP_CHALLENGE_ACK)) {
1000                         /* Detected RFC5961 challenge ACK */
1001                         ct->proto.tcp.last_flags &= ~IP_CT_EXP_CHALLENGE_ACK;
1002                         spin_unlock_bh(&ct->lock);
1003                         if (LOG_INVALID(net, IPPROTO_TCP))
1004                                 nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
1005                                       "nf_ct_tcp: challenge-ACK ignored ");
1006                         return NF_ACCEPT; /* Don't change state */
1007                 }
1008                 break;
1009         case TCP_CONNTRACK_CLOSE:
1010                 if (index == TCP_RST_SET
1011                     && (ct->proto.tcp.seen[!dir].flags & IP_CT_TCP_FLAG_MAXACK_SET)
1012                     && before(ntohl(th->seq), ct->proto.tcp.seen[!dir].td_maxack)) {
1013                         /* Invalid RST  */
1014                         spin_unlock_bh(&ct->lock);
1015                         if (LOG_INVALID(net, IPPROTO_TCP))
1016                                 nf_log_packet(net, pf, 0, skb, NULL, NULL,
1017                                               NULL, "nf_ct_tcp: invalid RST ");
1018                         return -NF_ACCEPT;
1019                 }
1020                 if (index == TCP_RST_SET
1021                     && ((test_bit(IPS_SEEN_REPLY_BIT, &ct->status)
1022                          && ct->proto.tcp.last_index == TCP_SYN_SET)
1023                         || (!test_bit(IPS_ASSURED_BIT, &ct->status)
1024                             && ct->proto.tcp.last_index == TCP_ACK_SET))
1025                     && ntohl(th->ack_seq) == ct->proto.tcp.last_end) {
1026                         /* RST sent to invalid SYN or ACK we had let through
1027                          * at a) and c) above:
1028                          *
1029                          * a) SYN was in window then
1030                          * c) we hold a half-open connection.
1031                          *
1032                          * Delete our connection entry.
1033                          * We skip window checking, because packet might ACK
1034                          * segments we ignored. */
1035                         goto in_window;
1036                 }
1037                 /* Just fall through */
1038         default:
1039                 /* Keep compilers happy. */
1040                 break;
1041         }
1042
1043         if (!tcp_in_window(ct, &ct->proto.tcp, dir, index,
1044                            skb, dataoff, th, pf)) {
1045                 spin_unlock_bh(&ct->lock);
1046                 return -NF_ACCEPT;
1047         }
1048      in_window:
1049         /* From now on we have got in-window packets */
1050         ct->proto.tcp.last_index = index;
1051         ct->proto.tcp.last_dir = dir;
1052
1053         pr_debug("tcp_conntracks: ");
1054         nf_ct_dump_tuple(tuple);
1055         pr_debug("syn=%i ack=%i fin=%i rst=%i old=%i new=%i\n",
1056                  (th->syn ? 1 : 0), (th->ack ? 1 : 0),
1057                  (th->fin ? 1 : 0), (th->rst ? 1 : 0),
1058                  old_state, new_state);
1059
1060         ct->proto.tcp.state = new_state;
1061         if (old_state != new_state
1062             && new_state == TCP_CONNTRACK_FIN_WAIT)
1063                 ct->proto.tcp.seen[dir].flags |= IP_CT_TCP_FLAG_CLOSE_INIT;
1064
1065         if (ct->proto.tcp.retrans >= tn->tcp_max_retrans &&
1066             timeouts[new_state] > timeouts[TCP_CONNTRACK_RETRANS])
1067                 timeout = timeouts[TCP_CONNTRACK_RETRANS];
1068         else if ((ct->proto.tcp.seen[0].flags | ct->proto.tcp.seen[1].flags) &
1069                  IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED &&
1070                  timeouts[new_state] > timeouts[TCP_CONNTRACK_UNACK])
1071                 timeout = timeouts[TCP_CONNTRACK_UNACK];
1072         else
1073                 timeout = timeouts[new_state];
1074         spin_unlock_bh(&ct->lock);
1075
1076         if (new_state != old_state)
1077                 nf_conntrack_event_cache(IPCT_PROTOINFO, ct);
1078
1079         if (!test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
1080                 /* If only reply is a RST, we can consider ourselves not to
1081                    have an established connection: this is a fairly common
1082                    problem case, so we can delete the conntrack
1083                    immediately.  --RR */
1084                 if (th->rst) {
1085                         nf_ct_kill_acct(ct, ctinfo, skb);
1086                         return NF_ACCEPT;
1087                 }
1088                 /* ESTABLISHED without SEEN_REPLY, i.e. mid-connection
1089                  * pickup with loose=1. Avoid large ESTABLISHED timeout.
1090                  */
1091                 if (new_state == TCP_CONNTRACK_ESTABLISHED &&
1092                     timeout > timeouts[TCP_CONNTRACK_UNACK])
1093                         timeout = timeouts[TCP_CONNTRACK_UNACK];
1094         } else if (!test_bit(IPS_ASSURED_BIT, &ct->status)
1095                    && (old_state == TCP_CONNTRACK_SYN_RECV
1096                        || old_state == TCP_CONNTRACK_ESTABLISHED)
1097                    && new_state == TCP_CONNTRACK_ESTABLISHED) {
1098                 /* Set ASSURED if we see see valid ack in ESTABLISHED
1099                    after SYN_RECV or a valid answer for a picked up
1100                    connection. */
1101                 set_bit(IPS_ASSURED_BIT, &ct->status);
1102                 nf_conntrack_event_cache(IPCT_ASSURED, ct);
1103         }
1104         nf_ct_refresh_acct(ct, ctinfo, skb, timeout);
1105
1106         return NF_ACCEPT;
1107 }
1108
1109 /* Called when a new connection for this protocol found. */
1110 static bool tcp_new(struct nf_conn *ct, const struct sk_buff *skb,
1111                     unsigned int dataoff, unsigned int *timeouts)
1112 {
1113         enum tcp_conntrack new_state;
1114         const struct tcphdr *th;
1115         struct tcphdr _tcph;
1116         struct net *net = nf_ct_net(ct);
1117         struct nf_tcp_net *tn = tcp_pernet(net);
1118         const struct ip_ct_tcp_state *sender = &ct->proto.tcp.seen[0];
1119         const struct ip_ct_tcp_state *receiver = &ct->proto.tcp.seen[1];
1120
1121         th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph);
1122         BUG_ON(th == NULL);
1123
1124         /* Don't need lock here: this conntrack not in circulation yet */
1125         new_state = tcp_conntracks[0][get_conntrack_index(th)][TCP_CONNTRACK_NONE];
1126
1127         /* Invalid: delete conntrack */
1128         if (new_state >= TCP_CONNTRACK_MAX) {
1129                 pr_debug("nf_ct_tcp: invalid new deleting.\n");
1130                 return false;
1131         }
1132
1133         if (new_state == TCP_CONNTRACK_SYN_SENT) {
1134                 memset(&ct->proto.tcp, 0, sizeof(ct->proto.tcp));
1135                 /* SYN packet */
1136                 ct->proto.tcp.seen[0].td_end =
1137                         segment_seq_plus_len(ntohl(th->seq), skb->len,
1138                                              dataoff, th);
1139                 ct->proto.tcp.seen[0].td_maxwin = ntohs(th->window);
1140                 if (ct->proto.tcp.seen[0].td_maxwin == 0)
1141                         ct->proto.tcp.seen[0].td_maxwin = 1;
1142                 ct->proto.tcp.seen[0].td_maxend =
1143                         ct->proto.tcp.seen[0].td_end;
1144
1145                 tcp_options(skb, dataoff, th, &ct->proto.tcp.seen[0]);
1146         } else if (tn->tcp_loose == 0) {
1147                 /* Don't try to pick up connections. */
1148                 return false;
1149         } else {
1150                 memset(&ct->proto.tcp, 0, sizeof(ct->proto.tcp));
1151                 /*
1152                  * We are in the middle of a connection,
1153                  * its history is lost for us.
1154                  * Let's try to use the data from the packet.
1155                  */
1156                 ct->proto.tcp.seen[0].td_end =
1157                         segment_seq_plus_len(ntohl(th->seq), skb->len,
1158                                              dataoff, th);
1159                 ct->proto.tcp.seen[0].td_maxwin = ntohs(th->window);
1160                 if (ct->proto.tcp.seen[0].td_maxwin == 0)
1161                         ct->proto.tcp.seen[0].td_maxwin = 1;
1162                 ct->proto.tcp.seen[0].td_maxend =
1163                         ct->proto.tcp.seen[0].td_end +
1164                         ct->proto.tcp.seen[0].td_maxwin;
1165
1166                 /* We assume SACK and liberal window checking to handle
1167                  * window scaling */
1168                 ct->proto.tcp.seen[0].flags =
1169                 ct->proto.tcp.seen[1].flags = IP_CT_TCP_FLAG_SACK_PERM |
1170                                               IP_CT_TCP_FLAG_BE_LIBERAL;
1171         }
1172
1173         /* tcp_packet will set them */
1174         ct->proto.tcp.last_index = TCP_NONE_SET;
1175
1176         pr_debug("tcp_new: sender end=%u maxend=%u maxwin=%u scale=%i "
1177                  "receiver end=%u maxend=%u maxwin=%u scale=%i\n",
1178                  sender->td_end, sender->td_maxend, sender->td_maxwin,
1179                  sender->td_scale,
1180                  receiver->td_end, receiver->td_maxend, receiver->td_maxwin,
1181                  receiver->td_scale);
1182         return true;
1183 }
1184
1185 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
1186
1187 #include <linux/netfilter/nfnetlink.h>
1188 #include <linux/netfilter/nfnetlink_conntrack.h>
1189
1190 static int tcp_to_nlattr(struct sk_buff *skb, struct nlattr *nla,
1191                          struct nf_conn *ct)
1192 {
1193         struct nlattr *nest_parms;
1194         struct nf_ct_tcp_flags tmp = {};
1195
1196         spin_lock_bh(&ct->lock);
1197         nest_parms = nla_nest_start(skb, CTA_PROTOINFO_TCP | NLA_F_NESTED);
1198         if (!nest_parms)
1199                 goto nla_put_failure;
1200
1201         if (nla_put_u8(skb, CTA_PROTOINFO_TCP_STATE, ct->proto.tcp.state) ||
1202             nla_put_u8(skb, CTA_PROTOINFO_TCP_WSCALE_ORIGINAL,
1203                        ct->proto.tcp.seen[0].td_scale) ||
1204             nla_put_u8(skb, CTA_PROTOINFO_TCP_WSCALE_REPLY,
1205                        ct->proto.tcp.seen[1].td_scale))
1206                 goto nla_put_failure;
1207
1208         tmp.flags = ct->proto.tcp.seen[0].flags;
1209         if (nla_put(skb, CTA_PROTOINFO_TCP_FLAGS_ORIGINAL,
1210                     sizeof(struct nf_ct_tcp_flags), &tmp))
1211                 goto nla_put_failure;
1212
1213         tmp.flags = ct->proto.tcp.seen[1].flags;
1214         if (nla_put(skb, CTA_PROTOINFO_TCP_FLAGS_REPLY,
1215                     sizeof(struct nf_ct_tcp_flags), &tmp))
1216                 goto nla_put_failure;
1217         spin_unlock_bh(&ct->lock);
1218
1219         nla_nest_end(skb, nest_parms);
1220
1221         return 0;
1222
1223 nla_put_failure:
1224         spin_unlock_bh(&ct->lock);
1225         return -1;
1226 }
1227
1228 static const struct nla_policy tcp_nla_policy[CTA_PROTOINFO_TCP_MAX+1] = {
1229         [CTA_PROTOINFO_TCP_STATE]           = { .type = NLA_U8 },
1230         [CTA_PROTOINFO_TCP_WSCALE_ORIGINAL] = { .type = NLA_U8 },
1231         [CTA_PROTOINFO_TCP_WSCALE_REPLY]    = { .type = NLA_U8 },
1232         [CTA_PROTOINFO_TCP_FLAGS_ORIGINAL]  = { .len = sizeof(struct nf_ct_tcp_flags) },
1233         [CTA_PROTOINFO_TCP_FLAGS_REPLY]     = { .len =  sizeof(struct nf_ct_tcp_flags) },
1234 };
1235
1236 static int nlattr_to_tcp(struct nlattr *cda[], struct nf_conn *ct)
1237 {
1238         struct nlattr *pattr = cda[CTA_PROTOINFO_TCP];
1239         struct nlattr *tb[CTA_PROTOINFO_TCP_MAX+1];
1240         int err;
1241
1242         /* updates could not contain anything about the private
1243          * protocol info, in that case skip the parsing */
1244         if (!pattr)
1245                 return 0;
1246
1247         err = nla_parse_nested(tb, CTA_PROTOINFO_TCP_MAX, pattr, tcp_nla_policy);
1248         if (err < 0)
1249                 return err;
1250
1251         if (tb[CTA_PROTOINFO_TCP_STATE] &&
1252             nla_get_u8(tb[CTA_PROTOINFO_TCP_STATE]) >= TCP_CONNTRACK_MAX)
1253                 return -EINVAL;
1254
1255         spin_lock_bh(&ct->lock);
1256         if (tb[CTA_PROTOINFO_TCP_STATE])
1257                 ct->proto.tcp.state = nla_get_u8(tb[CTA_PROTOINFO_TCP_STATE]);
1258
1259         if (tb[CTA_PROTOINFO_TCP_FLAGS_ORIGINAL]) {
1260                 struct nf_ct_tcp_flags *attr =
1261                         nla_data(tb[CTA_PROTOINFO_TCP_FLAGS_ORIGINAL]);
1262                 ct->proto.tcp.seen[0].flags &= ~attr->mask;
1263                 ct->proto.tcp.seen[0].flags |= attr->flags & attr->mask;
1264         }
1265
1266         if (tb[CTA_PROTOINFO_TCP_FLAGS_REPLY]) {
1267                 struct nf_ct_tcp_flags *attr =
1268                         nla_data(tb[CTA_PROTOINFO_TCP_FLAGS_REPLY]);
1269                 ct->proto.tcp.seen[1].flags &= ~attr->mask;
1270                 ct->proto.tcp.seen[1].flags |= attr->flags & attr->mask;
1271         }
1272
1273         if (tb[CTA_PROTOINFO_TCP_WSCALE_ORIGINAL] &&
1274             tb[CTA_PROTOINFO_TCP_WSCALE_REPLY] &&
1275             ct->proto.tcp.seen[0].flags & IP_CT_TCP_FLAG_WINDOW_SCALE &&
1276             ct->proto.tcp.seen[1].flags & IP_CT_TCP_FLAG_WINDOW_SCALE) {
1277                 ct->proto.tcp.seen[0].td_scale =
1278                         nla_get_u8(tb[CTA_PROTOINFO_TCP_WSCALE_ORIGINAL]);
1279                 ct->proto.tcp.seen[1].td_scale =
1280                         nla_get_u8(tb[CTA_PROTOINFO_TCP_WSCALE_REPLY]);
1281         }
1282         spin_unlock_bh(&ct->lock);
1283
1284         return 0;
1285 }
1286
1287 static int tcp_nlattr_size(void)
1288 {
1289         return nla_total_size(0)           /* CTA_PROTOINFO_TCP */
1290                 + nla_policy_len(tcp_nla_policy, CTA_PROTOINFO_TCP_MAX + 1);
1291 }
1292
1293 static int tcp_nlattr_tuple_size(void)
1294 {
1295         return nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1);
1296 }
1297 #endif
1298
1299 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
1300
1301 #include <linux/netfilter/nfnetlink.h>
1302 #include <linux/netfilter/nfnetlink_cttimeout.h>
1303
1304 static int tcp_timeout_nlattr_to_obj(struct nlattr *tb[],
1305                                      struct net *net, void *data)
1306 {
1307         unsigned int *timeouts = data;
1308         struct nf_tcp_net *tn = tcp_pernet(net);
1309         int i;
1310
1311         /* set default TCP timeouts. */
1312         for (i=0; i<TCP_CONNTRACK_TIMEOUT_MAX; i++)
1313                 timeouts[i] = tn->timeouts[i];
1314
1315         if (tb[CTA_TIMEOUT_TCP_SYN_SENT]) {
1316                 timeouts[TCP_CONNTRACK_SYN_SENT] =
1317                         ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_SYN_SENT]))*HZ;
1318         }
1319         if (tb[CTA_TIMEOUT_TCP_SYN_RECV]) {
1320                 timeouts[TCP_CONNTRACK_SYN_RECV] =
1321                         ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_SYN_RECV]))*HZ;
1322         }
1323         if (tb[CTA_TIMEOUT_TCP_ESTABLISHED]) {
1324                 timeouts[TCP_CONNTRACK_ESTABLISHED] =
1325                         ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_ESTABLISHED]))*HZ;
1326         }
1327         if (tb[CTA_TIMEOUT_TCP_FIN_WAIT]) {
1328                 timeouts[TCP_CONNTRACK_FIN_WAIT] =
1329                         ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_FIN_WAIT]))*HZ;
1330         }
1331         if (tb[CTA_TIMEOUT_TCP_CLOSE_WAIT]) {
1332                 timeouts[TCP_CONNTRACK_CLOSE_WAIT] =
1333                         ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_CLOSE_WAIT]))*HZ;
1334         }
1335         if (tb[CTA_TIMEOUT_TCP_LAST_ACK]) {
1336                 timeouts[TCP_CONNTRACK_LAST_ACK] =
1337                         ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_LAST_ACK]))*HZ;
1338         }
1339         if (tb[CTA_TIMEOUT_TCP_TIME_WAIT]) {
1340                 timeouts[TCP_CONNTRACK_TIME_WAIT] =
1341                         ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_TIME_WAIT]))*HZ;
1342         }
1343         if (tb[CTA_TIMEOUT_TCP_CLOSE]) {
1344                 timeouts[TCP_CONNTRACK_CLOSE] =
1345                         ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_CLOSE]))*HZ;
1346         }
1347         if (tb[CTA_TIMEOUT_TCP_SYN_SENT2]) {
1348                 timeouts[TCP_CONNTRACK_SYN_SENT2] =
1349                         ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_SYN_SENT2]))*HZ;
1350         }
1351         if (tb[CTA_TIMEOUT_TCP_RETRANS]) {
1352                 timeouts[TCP_CONNTRACK_RETRANS] =
1353                         ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_RETRANS]))*HZ;
1354         }
1355         if (tb[CTA_TIMEOUT_TCP_UNACK]) {
1356                 timeouts[TCP_CONNTRACK_UNACK] =
1357                         ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_UNACK]))*HZ;
1358         }
1359         return 0;
1360 }
1361
1362 static int
1363 tcp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
1364 {
1365         const unsigned int *timeouts = data;
1366
1367         if (nla_put_be32(skb, CTA_TIMEOUT_TCP_SYN_SENT,
1368                         htonl(timeouts[TCP_CONNTRACK_SYN_SENT] / HZ)) ||
1369             nla_put_be32(skb, CTA_TIMEOUT_TCP_SYN_RECV,
1370                          htonl(timeouts[TCP_CONNTRACK_SYN_RECV] / HZ)) ||
1371             nla_put_be32(skb, CTA_TIMEOUT_TCP_ESTABLISHED,
1372                          htonl(timeouts[TCP_CONNTRACK_ESTABLISHED] / HZ)) ||
1373             nla_put_be32(skb, CTA_TIMEOUT_TCP_FIN_WAIT,
1374                          htonl(timeouts[TCP_CONNTRACK_FIN_WAIT] / HZ)) ||
1375             nla_put_be32(skb, CTA_TIMEOUT_TCP_CLOSE_WAIT,
1376                          htonl(timeouts[TCP_CONNTRACK_CLOSE_WAIT] / HZ)) ||
1377             nla_put_be32(skb, CTA_TIMEOUT_TCP_LAST_ACK,
1378                          htonl(timeouts[TCP_CONNTRACK_LAST_ACK] / HZ)) ||
1379             nla_put_be32(skb, CTA_TIMEOUT_TCP_TIME_WAIT,
1380                          htonl(timeouts[TCP_CONNTRACK_TIME_WAIT] / HZ)) ||
1381             nla_put_be32(skb, CTA_TIMEOUT_TCP_CLOSE,
1382                          htonl(timeouts[TCP_CONNTRACK_CLOSE] / HZ)) ||
1383             nla_put_be32(skb, CTA_TIMEOUT_TCP_SYN_SENT2,
1384                          htonl(timeouts[TCP_CONNTRACK_SYN_SENT2] / HZ)) ||
1385             nla_put_be32(skb, CTA_TIMEOUT_TCP_RETRANS,
1386                          htonl(timeouts[TCP_CONNTRACK_RETRANS] / HZ)) ||
1387             nla_put_be32(skb, CTA_TIMEOUT_TCP_UNACK,
1388                          htonl(timeouts[TCP_CONNTRACK_UNACK] / HZ)))
1389                 goto nla_put_failure;
1390         return 0;
1391
1392 nla_put_failure:
1393         return -ENOSPC;
1394 }
1395
1396 static const struct nla_policy tcp_timeout_nla_policy[CTA_TIMEOUT_TCP_MAX+1] = {
1397         [CTA_TIMEOUT_TCP_SYN_SENT]      = { .type = NLA_U32 },
1398         [CTA_TIMEOUT_TCP_SYN_RECV]      = { .type = NLA_U32 },
1399         [CTA_TIMEOUT_TCP_ESTABLISHED]   = { .type = NLA_U32 },
1400         [CTA_TIMEOUT_TCP_FIN_WAIT]      = { .type = NLA_U32 },
1401         [CTA_TIMEOUT_TCP_CLOSE_WAIT]    = { .type = NLA_U32 },
1402         [CTA_TIMEOUT_TCP_LAST_ACK]      = { .type = NLA_U32 },
1403         [CTA_TIMEOUT_TCP_TIME_WAIT]     = { .type = NLA_U32 },
1404         [CTA_TIMEOUT_TCP_CLOSE]         = { .type = NLA_U32 },
1405         [CTA_TIMEOUT_TCP_SYN_SENT2]     = { .type = NLA_U32 },
1406         [CTA_TIMEOUT_TCP_RETRANS]       = { .type = NLA_U32 },
1407         [CTA_TIMEOUT_TCP_UNACK]         = { .type = NLA_U32 },
1408 };
1409 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
1410
1411 #ifdef CONFIG_SYSCTL
1412 static struct ctl_table tcp_sysctl_table[] = {
1413         {
1414                 .procname       = "nf_conntrack_tcp_timeout_syn_sent",
1415                 .maxlen         = sizeof(unsigned int),
1416                 .mode           = 0644,
1417                 .proc_handler   = proc_dointvec_jiffies,
1418         },
1419         {
1420                 .procname       = "nf_conntrack_tcp_timeout_syn_recv",
1421                 .maxlen         = sizeof(unsigned int),
1422                 .mode           = 0644,
1423                 .proc_handler   = proc_dointvec_jiffies,
1424         },
1425         {
1426                 .procname       = "nf_conntrack_tcp_timeout_established",
1427                 .maxlen         = sizeof(unsigned int),
1428                 .mode           = 0644,
1429                 .proc_handler   = proc_dointvec_jiffies,
1430         },
1431         {
1432                 .procname       = "nf_conntrack_tcp_timeout_fin_wait",
1433                 .maxlen         = sizeof(unsigned int),
1434                 .mode           = 0644,
1435                 .proc_handler   = proc_dointvec_jiffies,
1436         },
1437         {
1438                 .procname       = "nf_conntrack_tcp_timeout_close_wait",
1439                 .maxlen         = sizeof(unsigned int),
1440                 .mode           = 0644,
1441                 .proc_handler   = proc_dointvec_jiffies,
1442         },
1443         {
1444                 .procname       = "nf_conntrack_tcp_timeout_last_ack",
1445                 .maxlen         = sizeof(unsigned int),
1446                 .mode           = 0644,
1447                 .proc_handler   = proc_dointvec_jiffies,
1448         },
1449         {
1450                 .procname       = "nf_conntrack_tcp_timeout_time_wait",
1451                 .maxlen         = sizeof(unsigned int),
1452                 .mode           = 0644,
1453                 .proc_handler   = proc_dointvec_jiffies,
1454         },
1455         {
1456                 .procname       = "nf_conntrack_tcp_timeout_close",
1457                 .maxlen         = sizeof(unsigned int),
1458                 .mode           = 0644,
1459                 .proc_handler   = proc_dointvec_jiffies,
1460         },
1461         {
1462                 .procname       = "nf_conntrack_tcp_timeout_max_retrans",
1463                 .maxlen         = sizeof(unsigned int),
1464                 .mode           = 0644,
1465                 .proc_handler   = proc_dointvec_jiffies,
1466         },
1467         {
1468                 .procname       = "nf_conntrack_tcp_timeout_unacknowledged",
1469                 .maxlen         = sizeof(unsigned int),
1470                 .mode           = 0644,
1471                 .proc_handler   = proc_dointvec_jiffies,
1472         },
1473         {
1474                 .procname       = "nf_conntrack_tcp_loose",
1475                 .maxlen         = sizeof(unsigned int),
1476                 .mode           = 0644,
1477                 .proc_handler   = proc_dointvec,
1478         },
1479         {
1480                 .procname       = "nf_conntrack_tcp_be_liberal",
1481                 .maxlen         = sizeof(unsigned int),
1482                 .mode           = 0644,
1483                 .proc_handler   = proc_dointvec,
1484         },
1485         {
1486                 .procname       = "nf_conntrack_tcp_max_retrans",
1487                 .maxlen         = sizeof(unsigned int),
1488                 .mode           = 0644,
1489                 .proc_handler   = proc_dointvec,
1490         },
1491         { }
1492 };
1493 #endif /* CONFIG_SYSCTL */
1494
1495 static int tcp_kmemdup_sysctl_table(struct nf_proto_net *pn,
1496                                     struct nf_tcp_net *tn)
1497 {
1498 #ifdef CONFIG_SYSCTL
1499         if (pn->ctl_table)
1500                 return 0;
1501
1502         pn->ctl_table = kmemdup(tcp_sysctl_table,
1503                                 sizeof(tcp_sysctl_table),
1504                                 GFP_KERNEL);
1505         if (!pn->ctl_table)
1506                 return -ENOMEM;
1507
1508         pn->ctl_table[0].data = &tn->timeouts[TCP_CONNTRACK_SYN_SENT];
1509         pn->ctl_table[1].data = &tn->timeouts[TCP_CONNTRACK_SYN_RECV];
1510         pn->ctl_table[2].data = &tn->timeouts[TCP_CONNTRACK_ESTABLISHED];
1511         pn->ctl_table[3].data = &tn->timeouts[TCP_CONNTRACK_FIN_WAIT];
1512         pn->ctl_table[4].data = &tn->timeouts[TCP_CONNTRACK_CLOSE_WAIT];
1513         pn->ctl_table[5].data = &tn->timeouts[TCP_CONNTRACK_LAST_ACK];
1514         pn->ctl_table[6].data = &tn->timeouts[TCP_CONNTRACK_TIME_WAIT];
1515         pn->ctl_table[7].data = &tn->timeouts[TCP_CONNTRACK_CLOSE];
1516         pn->ctl_table[8].data = &tn->timeouts[TCP_CONNTRACK_RETRANS];
1517         pn->ctl_table[9].data = &tn->timeouts[TCP_CONNTRACK_UNACK];
1518         pn->ctl_table[10].data = &tn->tcp_loose;
1519         pn->ctl_table[11].data = &tn->tcp_be_liberal;
1520         pn->ctl_table[12].data = &tn->tcp_max_retrans;
1521 #endif
1522         return 0;
1523 }
1524
1525 static int tcp_init_net(struct net *net, u_int16_t proto)
1526 {
1527         struct nf_tcp_net *tn = tcp_pernet(net);
1528         struct nf_proto_net *pn = &tn->pn;
1529
1530         if (!pn->users) {
1531                 int i;
1532
1533                 for (i = 0; i < TCP_CONNTRACK_TIMEOUT_MAX; i++)
1534                         tn->timeouts[i] = tcp_timeouts[i];
1535
1536                 tn->tcp_loose = nf_ct_tcp_loose;
1537                 tn->tcp_be_liberal = nf_ct_tcp_be_liberal;
1538                 tn->tcp_max_retrans = nf_ct_tcp_max_retrans;
1539         }
1540
1541         return tcp_kmemdup_sysctl_table(pn, tn);
1542 }
1543
1544 static struct nf_proto_net *tcp_get_net_proto(struct net *net)
1545 {
1546         return &net->ct.nf_ct_proto.tcp.pn;
1547 }
1548
1549 struct nf_conntrack_l4proto nf_conntrack_l4proto_tcp4 __read_mostly =
1550 {
1551         .l3proto                = PF_INET,
1552         .l4proto                = IPPROTO_TCP,
1553         .name                   = "tcp",
1554         .pkt_to_tuple           = tcp_pkt_to_tuple,
1555         .invert_tuple           = tcp_invert_tuple,
1556         .print_tuple            = tcp_print_tuple,
1557         .print_conntrack        = tcp_print_conntrack,
1558         .packet                 = tcp_packet,
1559         .get_timeouts           = tcp_get_timeouts,
1560         .new                    = tcp_new,
1561         .error                  = tcp_error,
1562 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
1563         .to_nlattr              = tcp_to_nlattr,
1564         .nlattr_size            = tcp_nlattr_size,
1565         .from_nlattr            = nlattr_to_tcp,
1566         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
1567         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
1568         .nlattr_tuple_size      = tcp_nlattr_tuple_size,
1569         .nla_policy             = nf_ct_port_nla_policy,
1570 #endif
1571 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
1572         .ctnl_timeout           = {
1573                 .nlattr_to_obj  = tcp_timeout_nlattr_to_obj,
1574                 .obj_to_nlattr  = tcp_timeout_obj_to_nlattr,
1575                 .nlattr_max     = CTA_TIMEOUT_TCP_MAX,
1576                 .obj_size       = sizeof(unsigned int) *
1577                                         TCP_CONNTRACK_TIMEOUT_MAX,
1578                 .nla_policy     = tcp_timeout_nla_policy,
1579         },
1580 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
1581         .init_net               = tcp_init_net,
1582         .get_net_proto          = tcp_get_net_proto,
1583 };
1584 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_tcp4);
1585
1586 struct nf_conntrack_l4proto nf_conntrack_l4proto_tcp6 __read_mostly =
1587 {
1588         .l3proto                = PF_INET6,
1589         .l4proto                = IPPROTO_TCP,
1590         .name                   = "tcp",
1591         .pkt_to_tuple           = tcp_pkt_to_tuple,
1592         .invert_tuple           = tcp_invert_tuple,
1593         .print_tuple            = tcp_print_tuple,
1594         .print_conntrack        = tcp_print_conntrack,
1595         .packet                 = tcp_packet,
1596         .get_timeouts           = tcp_get_timeouts,
1597         .new                    = tcp_new,
1598         .error                  = tcp_error,
1599 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
1600         .to_nlattr              = tcp_to_nlattr,
1601         .nlattr_size            = tcp_nlattr_size,
1602         .from_nlattr            = nlattr_to_tcp,
1603         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
1604         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
1605         .nlattr_tuple_size      = tcp_nlattr_tuple_size,
1606         .nla_policy             = nf_ct_port_nla_policy,
1607 #endif
1608 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
1609         .ctnl_timeout           = {
1610                 .nlattr_to_obj  = tcp_timeout_nlattr_to_obj,
1611                 .obj_to_nlattr  = tcp_timeout_obj_to_nlattr,
1612                 .nlattr_max     = CTA_TIMEOUT_TCP_MAX,
1613                 .obj_size       = sizeof(unsigned int) *
1614                                         TCP_CONNTRACK_TIMEOUT_MAX,
1615                 .nla_policy     = tcp_timeout_nla_policy,
1616         },
1617 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
1618         .init_net               = tcp_init_net,
1619         .get_net_proto          = tcp_get_net_proto,
1620 };
1621 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_tcp6);