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 =
 394         state->flags = 0;
 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 /* Returns verdict for packet, or -1 for invalid. */
 810 static int tcp_packet(struct nf_conn *ct,
 811                       const struct sk_buff *skb,
 812                       unsigned int dataoff,
 813                       enum ip_conntrack_info ctinfo,
 814                       u_int8_t pf,
 815                       unsigned int hooknum,
 816                       unsigned int *timeouts)
 817 {
 818         struct net *net = nf_ct_net(ct);
 819         struct nf_tcp_net *tn = tcp_pernet(net);
 820         struct nf_conntrack_tuple *tuple;
 821         enum tcp_conntrack new_state, old_state;
 822         enum ip_conntrack_dir dir;
 823         const struct tcphdr *th;
 824         struct tcphdr _tcph;
 825         unsigned long timeout;
 826         unsigned int index;
 827
 828         th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph);
 829         BUG_ON(th == NULL);
 830
 831         spin_lock_bh(&ct->lock);
 832         old_state = ct->proto.tcp.state;
 833         dir = CTINFO2DIR(ctinfo);
 834         index = get_conntrack_index(th);
 835         new_state = tcp_conntracks[dir][index][old_state];
 836         tuple = &ct->tuplehash[dir].tuple;
 837
 838         switch (new_state) {
 839         case TCP_CONNTRACK_SYN_SENT:
 840                 if (old_state < TCP_CONNTRACK_TIME_WAIT)
 841                         break;
 842                 /* RFC 1122: "When a connection is closed actively,
 843                  * it MUST linger in TIME-WAIT state for a time 2xMSL
 844                  * (Maximum Segment Lifetime). However, it MAY accept
 845                  * a new SYN from the remote TCP to reopen the connection
 846                  * directly from TIME-WAIT state, if..."
 847                  * We ignore the conditions because we are in the
 848                  * TIME-WAIT state anyway.
 849                  *
 850                  * Handle aborted connections: we and the server
 851                  * think there is an existing connection but the client
 852                  * aborts it and starts a new one.
 853                  */
 854                 if (((ct->proto.tcp.seen[dir].flags
 855                       | ct->proto.tcp.seen[!dir].flags)
 856                      & IP_CT_TCP_FLAG_CLOSE_INIT)
 857                     || (ct->proto.tcp.last_dir == dir
 858                         && ct->proto.tcp.last_index == TCP_RST_SET)) {
 859                         /* Attempt to reopen a closed/aborted connection.
 860                          * Delete this connection and look up again. */
 861                         spin_unlock_bh(&ct->lock);
 862
 863                         /* Only repeat if we can actually remove the timer.
 864                          * Destruction may already be in progress in process
 865                          * context and we must give it a chance to terminate.
 866                          */
 867                         if (nf_ct_kill(ct))
 868                                 return -NF_REPEAT;
 869                         return NF_DROP;
 870                 }
 871                 /* Fall through */
 872         case TCP_CONNTRACK_IGNORE:
 873                 /* Ignored packets:
 874                  *
 875                  * Our connection entry may be out of sync, so ignore
 876                  * packets which may signal the real connection between
 877                  * the client and the server.
 878                  *
 879                  * a) SYN in ORIGINAL
 880                  * b) SYN/ACK in REPLY
 881                  * c) ACK in reply direction after initial SYN in original.
 882                  *
 883                  * If the ignored packet is invalid, the receiver will send
 884                  * a RST we'll catch below.
 885                  */
 886                 if (index == TCP_SYNACK_SET
 887                     && ct->proto.tcp.last_index == TCP_SYN_SET
 888                     && ct->proto.tcp.last_dir != dir
 889                     && ntohl(th->ack_seq) == ct->proto.tcp.last_end) {
 890                         /* b) This SYN/ACK acknowledges a SYN that we earlier
 891                          * ignored as invalid. This means that the client and
 892                          * the server are both in sync, while the firewall is
 893                          * not. We get in sync from the previously annotated
 894                          * values.
 895                          */
 896                         old_state = TCP_CONNTRACK_SYN_SENT;
 897                         new_state = TCP_CONNTRACK_SYN_RECV;
 898                         ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_end =
 899                                 ct->proto.tcp.last_end;
 900                         ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_maxend =
 901                                 ct->proto.tcp.last_end;
 902                         ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_maxwin =
 903                                 ct->proto.tcp.last_win == 0 ?
 904                                         1 : ct->proto.tcp.last_win;
 905                         ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_scale =
 906                                 ct->proto.tcp.last_wscale;
 907                         ct->proto.tcp.last_flags &= ~IP_CT_EXP_CHALLENGE_ACK;
 908                         ct->proto.tcp.seen[ct->proto.tcp.last_dir].flags =
 909                                 ct->proto.tcp.last_flags;
 910                         memset(&ct->proto.tcp.seen[dir], 0,
 911                                sizeof(struct ip_ct_tcp_state));
 912                         break;
 913                 }
 914                 ct->proto.tcp.last_index = index;
 915                 ct->proto.tcp.last_dir = dir;
 916                 ct->proto.tcp.last_seq = ntohl(th->seq);
 917                 ct->proto.tcp.last_end =
 918                     segment_seq_plus_len(ntohl(th->seq), skb->len, dataoff, th);
 919                 ct->proto.tcp.last_win = ntohs(th->window);
 920
 921                 /* a) This is a SYN in ORIGINAL. The client and the server
 922                  * may be in sync but we are not. In that case, we annotate
 923                  * the TCP options and let the packet go through. If it is a
 924                  * valid SYN packet, the server will reply with a SYN/ACK, and
 925                  * then we'll get in sync. Otherwise, the server potentially
 926                  * responds with a challenge ACK if implementing RFC5961.
 927                  */
 928                 if (index == TCP_SYN_SET && dir == IP_CT_DIR_ORIGINAL) {
 929                         struct ip_ct_tcp_state seen = {};
 930
 931                         ct->proto.tcp.last_flags =
 932                         ct->proto.tcp.last_wscale = 0;
 933                         tcp_options(skb, dataoff, th, &seen);
 934                         if (seen.flags & IP_CT_TCP_FLAG_WINDOW_SCALE) {
 935                                 ct->proto.tcp.last_flags |=
 936                                         IP_CT_TCP_FLAG_WINDOW_SCALE;
 937                                 ct->proto.tcp.last_wscale = seen.td_scale;
 938                         }
 939                         if (seen.flags & IP_CT_TCP_FLAG_SACK_PERM) {
 940                                 ct->proto.tcp.last_flags |=
 941                                         IP_CT_TCP_FLAG_SACK_PERM;
 942                         }
 943                         /* Mark the potential for RFC5961 challenge ACK,
 944                          * this pose a special problem for LAST_ACK state
 945                          * as ACK is intrepretated as ACKing last FIN.
 946                          */
 947                         if (old_state == TCP_CONNTRACK_LAST_ACK)
 948                                 ct->proto.tcp.last_flags |=
 949                                         IP_CT_EXP_CHALLENGE_ACK;
 950                 }
 951                 spin_unlock_bh(&ct->lock);
 952                 if (LOG_INVALID(net, IPPROTO_TCP))
 953                         nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
 954                                   "nf_ct_tcp: invalid packet ignored in "
 955                                   "state %s ", tcp_conntrack_names[old_state]);
 956                 return NF_ACCEPT;
 957         case TCP_CONNTRACK_MAX:
 958                 /* Special case for SYN proxy: when the SYN to the server or
 959                  * the SYN/ACK from the server is lost, the client may transmit
 960                  * a keep-alive packet while in SYN_SENT state. This needs to
 961                  * be associated with the original conntrack entry in order to
 962                  * generate a new SYN with the correct sequence number.
 963                  */
 964                 if (nfct_synproxy(ct) && old_state == TCP_CONNTRACK_SYN_SENT &&
 965                     index == TCP_ACK_SET && dir == IP_CT_DIR_ORIGINAL &&
 966                     ct->proto.tcp.last_dir == IP_CT_DIR_ORIGINAL &&
 967                     ct->proto.tcp.seen[dir].td_end - 1 == ntohl(th->seq)) {
 968                         pr_debug("nf_ct_tcp: SYN proxy client keep alive\n");
 969                         spin_unlock_bh(&ct->lock);
 970                         return NF_ACCEPT;
 971                 }
 972
 973                 /* Invalid packet */
 974                 pr_debug("nf_ct_tcp: Invalid dir=%i index=%u ostate=%u\n",
 975                          dir, get_conntrack_index(th), old_state);
 976                 spin_unlock_bh(&ct->lock);
 977                 if (LOG_INVALID(net, IPPROTO_TCP))
 978                         nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
 979                                   "nf_ct_tcp: invalid state ");
 980                 return -NF_ACCEPT;
 981         case TCP_CONNTRACK_TIME_WAIT:
 982                 /* RFC5961 compliance cause stack to send "challenge-ACK"
 983                  * e.g. in response to spurious SYNs.  Conntrack MUST
 984                  * not believe this ACK is acking last FIN.
 985                  */
 986                 if (old_state == TCP_CONNTRACK_LAST_ACK &&
 987                     index == TCP_ACK_SET &&
 988                     ct->proto.tcp.last_dir != dir &&
 989                     ct->proto.tcp.last_index == TCP_SYN_SET &&
 990                     (ct->proto.tcp.last_flags & IP_CT_EXP_CHALLENGE_ACK)) {
 991                         /* Detected RFC5961 challenge ACK */
 992                         ct->proto.tcp.last_flags &= ~IP_CT_EXP_CHALLENGE_ACK;
 993                         spin_unlock_bh(&ct->lock);
 994                         if (LOG_INVALID(net, IPPROTO_TCP))
 995                                 nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
 996                                       "nf_ct_tcp: challenge-ACK ignored ");
 997                         return NF_ACCEPT; /* Don't change state */
 998                 }
 999                 break;
1000         case TCP_CONNTRACK_CLOSE:
1001                 if (index == TCP_RST_SET
1002                     && (ct->proto.tcp.seen[!dir].flags & IP_CT_TCP_FLAG_MAXACK_SET)
1003                     && before(ntohl(th->seq), ct->proto.tcp.seen[!dir].td_maxack)) {
1004                         /* Invalid RST  */
1005                         spin_unlock_bh(&ct->lock);
1006                         if (LOG_INVALID(net, IPPROTO_TCP))
1007                                 nf_log_packet(net, pf, 0, skb, NULL, NULL,
1008                                               NULL, "nf_ct_tcp: invalid RST ");
1009                         return -NF_ACCEPT;
1010                 }
1011                 if (index == TCP_RST_SET
1012                     && ((test_bit(IPS_SEEN_REPLY_BIT, &ct->status)
1013                          && ct->proto.tcp.last_index == TCP_SYN_SET)
1014                         || (!test_bit(IPS_ASSURED_BIT, &ct->status)
1015                             && ct->proto.tcp.last_index == TCP_ACK_SET))
1016                     && ntohl(th->ack_seq) == ct->proto.tcp.last_end) {
1017                         /* RST sent to invalid SYN or ACK we had let through
1018                          * at a) and c) above:
1019                          *
1020                          * a) SYN was in window then
1021                          * c) we hold a half-open connection.
1022                          *
1023                          * Delete our connection entry.
1024                          * We skip window checking, because packet might ACK
1025                          * segments we ignored. */
1026                         goto in_window;
1027                 }
1028                 /* Just fall through */
1029         default:
1030                 /* Keep compilers happy. */
1031                 break;
1032         }
1033
1034         if (!tcp_in_window(ct, &ct->proto.tcp, dir, index,
1035                            skb, dataoff, th, pf)) {
1036                 spin_unlock_bh(&ct->lock);
1037                 return -NF_ACCEPT;
1038         }
1039      in_window:
1040         /* From now on we have got in-window packets */
1041         ct->proto.tcp.last_index = index;
1042         ct->proto.tcp.last_dir = dir;
1043
1044         pr_debug("tcp_conntracks: ");
1045         nf_ct_dump_tuple(tuple);
1046         pr_debug("syn=%i ack=%i fin=%i rst=%i old=%i new=%i\n",
1047                  (th->syn ? 1 : 0), (th->ack ? 1 : 0),
1048                  (th->fin ? 1 : 0), (th->rst ? 1 : 0),
1049                  old_state, new_state);
1050
1051         ct->proto.tcp.state = new_state;
1052         if (old_state != new_state
1053             && new_state == TCP_CONNTRACK_FIN_WAIT)
1054                 ct->proto.tcp.seen[dir].flags |= IP_CT_TCP_FLAG_CLOSE_INIT;
1055
1056         if (ct->proto.tcp.retrans >= tn->tcp_max_retrans &&
1057             timeouts[new_state] > timeouts[TCP_CONNTRACK_RETRANS])
1058                 timeout = timeouts[TCP_CONNTRACK_RETRANS];
1059         else if ((ct->proto.tcp.seen[0].flags | ct->proto.tcp.seen[1].flags) &
1060                  IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED &&
1061                  timeouts[new_state] > timeouts[TCP_CONNTRACK_UNACK])
1062                 timeout = timeouts[TCP_CONNTRACK_UNACK];
1063         else
1064                 timeout = timeouts[new_state];
1065         spin_unlock_bh(&ct->lock);
1066
1067         if (new_state != old_state)
1068                 nf_conntrack_event_cache(IPCT_PROTOINFO, ct);
1069
1070         if (!test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
1071                 /* If only reply is a RST, we can consider ourselves not to
1072                    have an established connection: this is a fairly common
1073                    problem case, so we can delete the conntrack
1074                    immediately.  --RR */
1075                 if (th->rst) {
1076                         nf_ct_kill_acct(ct, ctinfo, skb);
1077                         return NF_ACCEPT;
1078                 }
1079                 /* ESTABLISHED without SEEN_REPLY, i.e. mid-connection
1080                  * pickup with loose=1. Avoid large ESTABLISHED timeout.
1081                  */
1082                 if (new_state == TCP_CONNTRACK_ESTABLISHED &&
1083                     timeout > timeouts[TCP_CONNTRACK_UNACK])
1084                         timeout = timeouts[TCP_CONNTRACK_UNACK];
1085         } else if (!test_bit(IPS_ASSURED_BIT, &ct->status)
1086                    && (old_state == TCP_CONNTRACK_SYN_RECV
1087                        || old_state == TCP_CONNTRACK_ESTABLISHED)
1088                    && new_state == TCP_CONNTRACK_ESTABLISHED) {
1089                 /* Set ASSURED if we see see valid ack in ESTABLISHED
1090                    after SYN_RECV or a valid answer for a picked up
1091                    connection. */
1092                 set_bit(IPS_ASSURED_BIT, &ct->status);
1093                 nf_conntrack_event_cache(IPCT_ASSURED, ct);
1094         }
1095         nf_ct_refresh_acct(ct, ctinfo, skb, timeout);
1096
1097         return NF_ACCEPT;
1098 }
1099
1100 /* Called when a new connection for this protocol found. */
1101 static bool tcp_new(struct nf_conn *ct, const struct sk_buff *skb,
1102                     unsigned int dataoff, unsigned int *timeouts)
1103 {
1104         enum tcp_conntrack new_state;
1105         const struct tcphdr *th;
1106         struct tcphdr _tcph;
1107         struct net *net = nf_ct_net(ct);
1108         struct nf_tcp_net *tn = tcp_pernet(net);
1109         const struct ip_ct_tcp_state *sender = &ct->proto.tcp.seen[0];
1110         const struct ip_ct_tcp_state *receiver = &ct->proto.tcp.seen[1];
1111
1112         th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph);
1113         BUG_ON(th == NULL);
1114
1115         /* Don't need lock here: this conntrack not in circulation yet */
1116         new_state = tcp_conntracks[0][get_conntrack_index(th)][TCP_CONNTRACK_NONE];
1117
1118         /* Invalid: delete conntrack */
1119         if (new_state >= TCP_CONNTRACK_MAX) {
1120                 pr_debug("nf_ct_tcp: invalid new deleting.\n");
1121                 return false;
1122         }
1123
1124         if (new_state == TCP_CONNTRACK_SYN_SENT) {
1125                 memset(&ct->proto.tcp, 0, sizeof(ct->proto.tcp));
1126                 /* SYN packet */
1127                 ct->proto.tcp.seen[0].td_end =
1128                         segment_seq_plus_len(ntohl(th->seq), skb->len,
1129                                              dataoff, th);
1130                 ct->proto.tcp.seen[0].td_maxwin = ntohs(th->window);
1131                 if (ct->proto.tcp.seen[0].td_maxwin == 0)
1132                         ct->proto.tcp.seen[0].td_maxwin = 1;
1133                 ct->proto.tcp.seen[0].td_maxend =
1134                         ct->proto.tcp.seen[0].td_end;
1135
1136                 tcp_options(skb, dataoff, th, &ct->proto.tcp.seen[0]);
1137         } else if (tn->tcp_loose == 0) {
1138                 /* Don't try to pick up connections. */
1139                 return false;
1140         } else {
1141                 memset(&ct->proto.tcp, 0, sizeof(ct->proto.tcp));
1142                 /*
1143                  * We are in the middle of a connection,
1144                  * its history is lost for us.
1145                  * Let's try to use the data from the packet.
1146                  */
1147                 ct->proto.tcp.seen[0].td_end =
1148                         segment_seq_plus_len(ntohl(th->seq), skb->len,
1149                                              dataoff, th);
1150                 ct->proto.tcp.seen[0].td_maxwin = ntohs(th->window);
1151                 if (ct->proto.tcp.seen[0].td_maxwin == 0)
1152                         ct->proto.tcp.seen[0].td_maxwin = 1;
1153                 ct->proto.tcp.seen[0].td_maxend =
1154                         ct->proto.tcp.seen[0].td_end +
1155                         ct->proto.tcp.seen[0].td_maxwin;
1156
1157                 /* We assume SACK and liberal window checking to handle
1158                  * window scaling */
1159                 ct->proto.tcp.seen[0].flags =
1160                 ct->proto.tcp.seen[1].flags = IP_CT_TCP_FLAG_SACK_PERM |
1161                                               IP_CT_TCP_FLAG_BE_LIBERAL;
1162         }
1163
1164         /* tcp_packet will set them */
1165         ct->proto.tcp.last_index = TCP_NONE_SET;
1166
1167         pr_debug("tcp_new: sender end=%u maxend=%u maxwin=%u scale=%i "
1168                  "receiver end=%u maxend=%u maxwin=%u scale=%i\n",
1169                  sender->td_end, sender->td_maxend, sender->td_maxwin,
1170                  sender->td_scale,
1171                  receiver->td_end, receiver->td_maxend, receiver->td_maxwin,
1172                  receiver->td_scale);
1173         return true;
1174 }
1175
1176 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
1177
1178 #include <linux/netfilter/nfnetlink.h>
1179 #include <linux/netfilter/nfnetlink_conntrack.h>
1180
1181 static int tcp_to_nlattr(struct sk_buff *skb, struct nlattr *nla,
1182                          struct nf_conn *ct)
1183 {
1184         struct nlattr *nest_parms;
1185         struct nf_ct_tcp_flags tmp = {};
1186
1187         spin_lock_bh(&ct->lock);
1188         nest_parms = nla_nest_start(skb, CTA_PROTOINFO_TCP | NLA_F_NESTED);
1189         if (!nest_parms)
1190                 goto nla_put_failure;
1191
1192         if (nla_put_u8(skb, CTA_PROTOINFO_TCP_STATE, ct->proto.tcp.state) ||
1193             nla_put_u8(skb, CTA_PROTOINFO_TCP_WSCALE_ORIGINAL,
1194                        ct->proto.tcp.seen[0].td_scale) ||
1195             nla_put_u8(skb, CTA_PROTOINFO_TCP_WSCALE_REPLY,
1196                        ct->proto.tcp.seen[1].td_scale))
1197                 goto nla_put_failure;
1198
1199         tmp.flags = ct->proto.tcp.seen[0].flags;
1200         if (nla_put(skb, CTA_PROTOINFO_TCP_FLAGS_ORIGINAL,
1201                     sizeof(struct nf_ct_tcp_flags), &tmp))
1202                 goto nla_put_failure;
1203
1204         tmp.flags = ct->proto.tcp.seen[1].flags;
1205         if (nla_put(skb, CTA_PROTOINFO_TCP_FLAGS_REPLY,
1206                     sizeof(struct nf_ct_tcp_flags), &tmp))
1207                 goto nla_put_failure;
1208         spin_unlock_bh(&ct->lock);
1209
1210         nla_nest_end(skb, nest_parms);
1211
1212         return 0;
1213
1214 nla_put_failure:
1215         spin_unlock_bh(&ct->lock);
1216         return -1;
1217 }
1218
1219 static const struct nla_policy tcp_nla_policy[CTA_PROTOINFO_TCP_MAX+1] = {
1220         [CTA_PROTOINFO_TCP_STATE]           = { .type = NLA_U8 },
1221         [CTA_PROTOINFO_TCP_WSCALE_ORIGINAL] = { .type = NLA_U8 },
1222         [CTA_PROTOINFO_TCP_WSCALE_REPLY]    = { .type = NLA_U8 },
1223         [CTA_PROTOINFO_TCP_FLAGS_ORIGINAL]  = { .len = sizeof(struct nf_ct_tcp_flags) },
1224         [CTA_PROTOINFO_TCP_FLAGS_REPLY]     = { .len =  sizeof(struct nf_ct_tcp_flags) },
1225 };
1226
1227 static int nlattr_to_tcp(struct nlattr *cda[], struct nf_conn *ct)
1228 {
1229         struct nlattr *pattr = cda[CTA_PROTOINFO_TCP];
1230         struct nlattr *tb[CTA_PROTOINFO_TCP_MAX+1];
1231         int err;
1232
1233         /* updates could not contain anything about the private
1234          * protocol info, in that case skip the parsing */
1235         if (!pattr)
1236                 return 0;
1237
1238         err = nla_parse_nested(tb, CTA_PROTOINFO_TCP_MAX, pattr, tcp_nla_policy);
1239         if (err < 0)
1240                 return err;
1241
1242         if (tb[CTA_PROTOINFO_TCP_STATE] &&
1243             nla_get_u8(tb[CTA_PROTOINFO_TCP_STATE]) >= TCP_CONNTRACK_MAX)
1244                 return -EINVAL;
1245
1246         spin_lock_bh(&ct->lock);
1247         if (tb[CTA_PROTOINFO_TCP_STATE])
1248                 ct->proto.tcp.state = nla_get_u8(tb[CTA_PROTOINFO_TCP_STATE]);
1249
1250         if (tb[CTA_PROTOINFO_TCP_FLAGS_ORIGINAL]) {
1251                 struct nf_ct_tcp_flags *attr =
1252                         nla_data(tb[CTA_PROTOINFO_TCP_FLAGS_ORIGINAL]);
1253                 ct->proto.tcp.seen[0].flags &= ~attr->mask;
1254                 ct->proto.tcp.seen[0].flags |= attr->flags & attr->mask;
1255         }
1256
1257         if (tb[CTA_PROTOINFO_TCP_FLAGS_REPLY]) {
1258                 struct nf_ct_tcp_flags *attr =
1259                         nla_data(tb[CTA_PROTOINFO_TCP_FLAGS_REPLY]);
1260                 ct->proto.tcp.seen[1].flags &= ~attr->mask;
1261                 ct->proto.tcp.seen[1].flags |= attr->flags & attr->mask;
1262         }
1263
1264         if (tb[CTA_PROTOINFO_TCP_WSCALE_ORIGINAL] &&
1265             tb[CTA_PROTOINFO_TCP_WSCALE_REPLY] &&
1266             ct->proto.tcp.seen[0].flags & IP_CT_TCP_FLAG_WINDOW_SCALE &&
1267             ct->proto.tcp.seen[1].flags & IP_CT_TCP_FLAG_WINDOW_SCALE) {
1268                 ct->proto.tcp.seen[0].td_scale =
1269                         nla_get_u8(tb[CTA_PROTOINFO_TCP_WSCALE_ORIGINAL]);
1270                 ct->proto.tcp.seen[1].td_scale =
1271                         nla_get_u8(tb[CTA_PROTOINFO_TCP_WSCALE_REPLY]);
1272         }
1273         spin_unlock_bh(&ct->lock);
1274
1275         return 0;
1276 }
1277
1278 static int tcp_nlattr_size(void)
1279 {
1280         return nla_total_size(0)           /* CTA_PROTOINFO_TCP */
1281                 + nla_policy_len(tcp_nla_policy, CTA_PROTOINFO_TCP_MAX + 1);
1282 }
1283
1284 static int tcp_nlattr_tuple_size(void)
1285 {
1286         return nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1);
1287 }
1288 #endif
1289
1290 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
1291
1292 #include <linux/netfilter/nfnetlink.h>
1293 #include <linux/netfilter/nfnetlink_cttimeout.h>
1294
1295 static int tcp_timeout_nlattr_to_obj(struct nlattr *tb[],
1296                                      struct net *net, void *data)
1297 {
1298         unsigned int *timeouts = data;
1299         struct nf_tcp_net *tn = tcp_pernet(net);
1300         int i;
1301
1302         /* set default TCP timeouts. */
1303         for (i=0; i<TCP_CONNTRACK_TIMEOUT_MAX; i++)
1304                 timeouts[i] = tn->timeouts[i];
1305
1306         if (tb[CTA_TIMEOUT_TCP_SYN_SENT]) {
1307                 timeouts[TCP_CONNTRACK_SYN_SENT] =
1308                         ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_SYN_SENT]))*HZ;
1309         }
1310         if (tb[CTA_TIMEOUT_TCP_SYN_RECV]) {
1311                 timeouts[TCP_CONNTRACK_SYN_RECV] =
1312                         ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_SYN_RECV]))*HZ;
1313         }
1314         if (tb[CTA_TIMEOUT_TCP_ESTABLISHED]) {
1315                 timeouts[TCP_CONNTRACK_ESTABLISHED] =
1316                         ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_ESTABLISHED]))*HZ;
1317         }
1318         if (tb[CTA_TIMEOUT_TCP_FIN_WAIT]) {
1319                 timeouts[TCP_CONNTRACK_FIN_WAIT] =
1320                         ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_FIN_WAIT]))*HZ;
1321         }
1322         if (tb[CTA_TIMEOUT_TCP_CLOSE_WAIT]) {
1323                 timeouts[TCP_CONNTRACK_CLOSE_WAIT] =
1324                         ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_CLOSE_WAIT]))*HZ;
1325         }
1326         if (tb[CTA_TIMEOUT_TCP_LAST_ACK]) {
1327                 timeouts[TCP_CONNTRACK_LAST_ACK] =
1328                         ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_LAST_ACK]))*HZ;
1329         }
1330         if (tb[CTA_TIMEOUT_TCP_TIME_WAIT]) {
1331                 timeouts[TCP_CONNTRACK_TIME_WAIT] =
1332                         ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_TIME_WAIT]))*HZ;
1333         }
1334         if (tb[CTA_TIMEOUT_TCP_CLOSE]) {
1335                 timeouts[TCP_CONNTRACK_CLOSE] =
1336                         ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_CLOSE]))*HZ;
1337         }
1338         if (tb[CTA_TIMEOUT_TCP_SYN_SENT2]) {
1339                 timeouts[TCP_CONNTRACK_SYN_SENT2] =
1340                         ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_SYN_SENT2]))*HZ;
1341         }
1342         if (tb[CTA_TIMEOUT_TCP_RETRANS]) {
1343                 timeouts[TCP_CONNTRACK_RETRANS] =
1344                         ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_RETRANS]))*HZ;
1345         }
1346         if (tb[CTA_TIMEOUT_TCP_UNACK]) {
1347                 timeouts[TCP_CONNTRACK_UNACK] =
1348                         ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_UNACK]))*HZ;
1349         }
1350         return 0;
1351 }
1352
1353 static int
1354 tcp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
1355 {
1356         const unsigned int *timeouts = data;
1357
1358         if (nla_put_be32(skb, CTA_TIMEOUT_TCP_SYN_SENT,
1359                         htonl(timeouts[TCP_CONNTRACK_SYN_SENT] / HZ)) ||
1360             nla_put_be32(skb, CTA_TIMEOUT_TCP_SYN_RECV,
1361                          htonl(timeouts[TCP_CONNTRACK_SYN_RECV] / HZ)) ||
1362             nla_put_be32(skb, CTA_TIMEOUT_TCP_ESTABLISHED,
1363                          htonl(timeouts[TCP_CONNTRACK_ESTABLISHED] / HZ)) ||
1364             nla_put_be32(skb, CTA_TIMEOUT_TCP_FIN_WAIT,
1365                          htonl(timeouts[TCP_CONNTRACK_FIN_WAIT] / HZ)) ||
1366             nla_put_be32(skb, CTA_TIMEOUT_TCP_CLOSE_WAIT,
1367                          htonl(timeouts[TCP_CONNTRACK_CLOSE_WAIT] / HZ)) ||
1368             nla_put_be32(skb, CTA_TIMEOUT_TCP_LAST_ACK,
1369                          htonl(timeouts[TCP_CONNTRACK_LAST_ACK] / HZ)) ||
1370             nla_put_be32(skb, CTA_TIMEOUT_TCP_TIME_WAIT,
1371                          htonl(timeouts[TCP_CONNTRACK_TIME_WAIT] / HZ)) ||
1372             nla_put_be32(skb, CTA_TIMEOUT_TCP_CLOSE,
1373                          htonl(timeouts[TCP_CONNTRACK_CLOSE] / HZ)) ||
1374             nla_put_be32(skb, CTA_TIMEOUT_TCP_SYN_SENT2,
1375                          htonl(timeouts[TCP_CONNTRACK_SYN_SENT2] / HZ)) ||
1376             nla_put_be32(skb, CTA_TIMEOUT_TCP_RETRANS,
1377                          htonl(timeouts[TCP_CONNTRACK_RETRANS] / HZ)) ||
1378             nla_put_be32(skb, CTA_TIMEOUT_TCP_UNACK,
1379                          htonl(timeouts[TCP_CONNTRACK_UNACK] / HZ)))
1380                 goto nla_put_failure;
1381         return 0;
1382
1383 nla_put_failure:
1384         return -ENOSPC;
1385 }
1386
1387 static const struct nla_policy tcp_timeout_nla_policy[CTA_TIMEOUT_TCP_MAX+1] = {
1388         [CTA_TIMEOUT_TCP_SYN_SENT]      = { .type = NLA_U32 },
1389         [CTA_TIMEOUT_TCP_SYN_RECV]      = { .type = NLA_U32 },
1390         [CTA_TIMEOUT_TCP_ESTABLISHED]   = { .type = NLA_U32 },
1391         [CTA_TIMEOUT_TCP_FIN_WAIT]      = { .type = NLA_U32 },
1392         [CTA_TIMEOUT_TCP_CLOSE_WAIT]    = { .type = NLA_U32 },
1393         [CTA_TIMEOUT_TCP_LAST_ACK]      = { .type = NLA_U32 },
1394         [CTA_TIMEOUT_TCP_TIME_WAIT]     = { .type = NLA_U32 },
1395         [CTA_TIMEOUT_TCP_CLOSE]         = { .type = NLA_U32 },
1396         [CTA_TIMEOUT_TCP_SYN_SENT2]     = { .type = NLA_U32 },
1397         [CTA_TIMEOUT_TCP_RETRANS]       = { .type = NLA_U32 },
1398         [CTA_TIMEOUT_TCP_UNACK]         = { .type = NLA_U32 },
1399 };
1400 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
1401
1402 #ifdef CONFIG_SYSCTL
1403 static struct ctl_table tcp_sysctl_table[] = {
1404         {
1405                 .procname       = "nf_conntrack_tcp_timeout_syn_sent",
1406                 .maxlen         = sizeof(unsigned int),
1407                 .mode           = 0644,
1408                 .proc_handler   = proc_dointvec_jiffies,
1409         },
1410         {
1411                 .procname       = "nf_conntrack_tcp_timeout_syn_recv",
1412                 .maxlen         = sizeof(unsigned int),
1413                 .mode           = 0644,
1414                 .proc_handler   = proc_dointvec_jiffies,
1415         },
1416         {
1417                 .procname       = "nf_conntrack_tcp_timeout_established",
1418                 .maxlen         = sizeof(unsigned int),
1419                 .mode           = 0644,
1420                 .proc_handler   = proc_dointvec_jiffies,
1421         },
1422         {
1423                 .procname       = "nf_conntrack_tcp_timeout_fin_wait",
1424                 .maxlen         = sizeof(unsigned int),
1425                 .mode           = 0644,
1426                 .proc_handler   = proc_dointvec_jiffies,
1427         },
1428         {
1429                 .procname       = "nf_conntrack_tcp_timeout_close_wait",
1430                 .maxlen         = sizeof(unsigned int),
1431                 .mode           = 0644,
1432                 .proc_handler   = proc_dointvec_jiffies,
1433         },
1434         {
1435                 .procname       = "nf_conntrack_tcp_timeout_last_ack",
1436                 .maxlen         = sizeof(unsigned int),
1437                 .mode           = 0644,
1438                 .proc_handler   = proc_dointvec_jiffies,
1439         },
1440         {
1441                 .procname       = "nf_conntrack_tcp_timeout_time_wait",
1442                 .maxlen         = sizeof(unsigned int),
1443                 .mode           = 0644,
1444                 .proc_handler   = proc_dointvec_jiffies,
1445         },
1446         {
1447                 .procname       = "nf_conntrack_tcp_timeout_close",
1448                 .maxlen         = sizeof(unsigned int),
1449                 .mode           = 0644,
1450                 .proc_handler   = proc_dointvec_jiffies,
1451         },
1452         {
1453                 .procname       = "nf_conntrack_tcp_timeout_max_retrans",
1454                 .maxlen         = sizeof(unsigned int),
1455                 .mode           = 0644,
1456                 .proc_handler   = proc_dointvec_jiffies,
1457         },
1458         {
1459                 .procname       = "nf_conntrack_tcp_timeout_unacknowledged",
1460                 .maxlen         = sizeof(unsigned int),
1461                 .mode           = 0644,
1462                 .proc_handler   = proc_dointvec_jiffies,
1463         },
1464         {
1465                 .procname       = "nf_conntrack_tcp_loose",
1466                 .maxlen         = sizeof(unsigned int),
1467                 .mode           = 0644,
1468                 .proc_handler   = proc_dointvec,
1469         },
1470         {
1471                 .procname       = "nf_conntrack_tcp_be_liberal",
1472                 .maxlen         = sizeof(unsigned int),
1473                 .mode           = 0644,
1474                 .proc_handler   = proc_dointvec,
1475         },
1476         {
1477                 .procname       = "nf_conntrack_tcp_max_retrans",
1478                 .maxlen         = sizeof(unsigned int),
1479                 .mode           = 0644,
1480                 .proc_handler   = proc_dointvec,
1481         },
1482         { }
1483 };
1484 #endif /* CONFIG_SYSCTL */
1485
1486 static int tcp_kmemdup_sysctl_table(struct nf_proto_net *pn,
1487                                     struct nf_tcp_net *tn)
1488 {
1489 #ifdef CONFIG_SYSCTL
1490         if (pn->ctl_table)
1491                 return 0;
1492
1493         pn->ctl_table = kmemdup(tcp_sysctl_table,
1494                                 sizeof(tcp_sysctl_table),
1495                                 GFP_KERNEL);
1496         if (!pn->ctl_table)
1497                 return -ENOMEM;
1498
1499         pn->ctl_table[0].data = &tn->timeouts[TCP_CONNTRACK_SYN_SENT];
1500         pn->ctl_table[1].data = &tn->timeouts[TCP_CONNTRACK_SYN_RECV];
1501         pn->ctl_table[2].data = &tn->timeouts[TCP_CONNTRACK_ESTABLISHED];
1502         pn->ctl_table[3].data = &tn->timeouts[TCP_CONNTRACK_FIN_WAIT];
1503         pn->ctl_table[4].data = &tn->timeouts[TCP_CONNTRACK_CLOSE_WAIT];
1504         pn->ctl_table[5].data = &tn->timeouts[TCP_CONNTRACK_LAST_ACK];
1505         pn->ctl_table[6].data = &tn->timeouts[TCP_CONNTRACK_TIME_WAIT];
1506         pn->ctl_table[7].data = &tn->timeouts[TCP_CONNTRACK_CLOSE];
1507         pn->ctl_table[8].data = &tn->timeouts[TCP_CONNTRACK_RETRANS];
1508         pn->ctl_table[9].data = &tn->timeouts[TCP_CONNTRACK_UNACK];
1509         pn->ctl_table[10].data = &tn->tcp_loose;
1510         pn->ctl_table[11].data = &tn->tcp_be_liberal;
1511         pn->ctl_table[12].data = &tn->tcp_max_retrans;
1512 #endif
1513         return 0;
1514 }
1515
1516 static int tcp_init_net(struct net *net, u_int16_t proto)
1517 {
1518         struct nf_tcp_net *tn = tcp_pernet(net);
1519         struct nf_proto_net *pn = &tn->pn;
1520
1521         if (!pn->users) {
1522                 int i;
1523
1524                 for (i = 0; i < TCP_CONNTRACK_TIMEOUT_MAX; i++)
1525                         tn->timeouts[i] = tcp_timeouts[i];
1526
1527                 tn->tcp_loose = nf_ct_tcp_loose;
1528                 tn->tcp_be_liberal = nf_ct_tcp_be_liberal;
1529                 tn->tcp_max_retrans = nf_ct_tcp_max_retrans;
1530         }
1531
1532         return tcp_kmemdup_sysctl_table(pn, tn);
1533 }
1534
1535 static struct nf_proto_net *tcp_get_net_proto(struct net *net)
1536 {
1537         return &net->ct.nf_ct_proto.tcp.pn;
1538 }
1539
1540 struct nf_conntrack_l4proto nf_conntrack_l4proto_tcp4 __read_mostly =
1541 {
1542         .l3proto                = PF_INET,
1543         .l4proto                = IPPROTO_TCP,
1544         .name                   = "tcp",
1545         .pkt_to_tuple           = tcp_pkt_to_tuple,
1546         .invert_tuple           = tcp_invert_tuple,
1547         .print_tuple            = tcp_print_tuple,
1548         .print_conntrack        = tcp_print_conntrack,
1549         .packet                 = tcp_packet,
1550         .get_timeouts           = tcp_get_timeouts,
1551         .new                    = tcp_new,
1552         .error                  = tcp_error,
1553 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
1554         .to_nlattr              = tcp_to_nlattr,
1555         .nlattr_size            = tcp_nlattr_size,
1556         .from_nlattr            = nlattr_to_tcp,
1557         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
1558         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
1559         .nlattr_tuple_size      = tcp_nlattr_tuple_size,
1560         .nla_policy             = nf_ct_port_nla_policy,
1561 #endif
1562 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
1563         .ctnl_timeout           = {
1564                 .nlattr_to_obj  = tcp_timeout_nlattr_to_obj,
1565                 .obj_to_nlattr  = tcp_timeout_obj_to_nlattr,
1566                 .nlattr_max     = CTA_TIMEOUT_TCP_MAX,
1567                 .obj_size       = sizeof(unsigned int) *
1568                                         TCP_CONNTRACK_TIMEOUT_MAX,
1569                 .nla_policy     = tcp_timeout_nla_policy,
1570         },
1571 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
1572         .init_net               = tcp_init_net,
1573         .get_net_proto          = tcp_get_net_proto,
1574 };
1575 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_tcp4);
1576
1577 struct nf_conntrack_l4proto nf_conntrack_l4proto_tcp6 __read_mostly =
1578 {
1579         .l3proto                = PF_INET6,
1580         .l4proto                = IPPROTO_TCP,
1581         .name                   = "tcp",
1582         .pkt_to_tuple           = tcp_pkt_to_tuple,
1583         .invert_tuple           = tcp_invert_tuple,
1584         .print_tuple            = tcp_print_tuple,
1585         .print_conntrack        = tcp_print_conntrack,
1586         .packet                 = tcp_packet,
1587         .get_timeouts           = tcp_get_timeouts,
1588         .new                    = tcp_new,
1589         .error                  = tcp_error,
1590 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
1591         .to_nlattr              = tcp_to_nlattr,
1592         .nlattr_size            = tcp_nlattr_size,
1593         .from_nlattr            = nlattr_to_tcp,
1594         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
1595         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
1596         .nlattr_tuple_size      = tcp_nlattr_tuple_size,
1597         .nla_policy             = nf_ct_port_nla_policy,
1598 #endif
1599 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
1600         .ctnl_timeout           = {
1601                 .nlattr_to_obj  = tcp_timeout_nlattr_to_obj,
1602                 .obj_to_nlattr  = tcp_timeout_obj_to_nlattr,
1603                 .nlattr_max     = CTA_TIMEOUT_TCP_MAX,
1604                 .obj_size       = sizeof(unsigned int) *
1605                                         TCP_CONNTRACK_TIMEOUT_MAX,
1606                 .nla_policy     = tcp_timeout_nla_policy,
1607         },
1608 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
1609         .init_net               = tcp_init_net,
1610         .get_net_proto          = tcp_get_net_proto,
1611 };
1612 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_tcp6);