net/netfilter/nf_conntrack_proto_sctp.c

   1 /*
   2  * Connection tracking protocol helper module for SCTP.
   3  *
   4  * Copyright (c) 2004 Kiran Kumar Immidi <immidi_kiran@yahoo.com>
   5  * Copyright (c) 2004-2012 Patrick McHardy <kaber@trash.net>
   6  *
   7  * SCTP is defined in RFC 2960. References to various sections in this code
   8  * are to this RFC.
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 as
  12  * published by the Free Software Foundation.
  13  */
  14
  15 #include <linux/types.h>
  16 #include <linux/timer.h>
  17 #include <linux/netfilter.h>
  18 #include <linux/in.h>
  19 #include <linux/ip.h>
  20 #include <linux/sctp.h>
  21 #include <linux/string.h>
  22 #include <linux/seq_file.h>
  23 #include <linux/spinlock.h>
  24 #include <linux/interrupt.h>
  25 #include <net/sctp/checksum.h>
  26
  27 #include <net/netfilter/nf_log.h>
  28 #include <net/netfilter/nf_conntrack.h>
  29 #include <net/netfilter/nf_conntrack_l4proto.h>
  30 #include <net/netfilter/nf_conntrack_ecache.h>
  31 #include <net/netfilter/nf_conntrack_timeout.h>
  32
  33 /* FIXME: Examine ipfilter's timeouts and conntrack transitions more
  34    closely.  They're more complex. --RR
  35
  36    And so for me for SCTP :D -Kiran */
  37
  38 static const char *const sctp_conntrack_names[] = {
  39         "NONE",
  40         "CLOSED",
  41         "COOKIE_WAIT",
  42         "COOKIE_ECHOED",
  43         "ESTABLISHED",
  44         "SHUTDOWN_SENT",
  45         "SHUTDOWN_RECD",
  46         "SHUTDOWN_ACK_SENT",
  47         "HEARTBEAT_SENT",
  48         "HEARTBEAT_ACKED",
  49 };
  50
  51 #define SECS  * HZ
  52 #define MINS  * 60 SECS
  53 #define HOURS * 60 MINS
  54 #define DAYS  * 24 HOURS
  55
  56 static const unsigned int sctp_timeouts[SCTP_CONNTRACK_MAX] = {
  57         [SCTP_CONNTRACK_CLOSED]                 = 10 SECS,
  58         [SCTP_CONNTRACK_COOKIE_WAIT]            = 3 SECS,
  59         [SCTP_CONNTRACK_COOKIE_ECHOED]          = 3 SECS,
  60         [SCTP_CONNTRACK_ESTABLISHED]            = 5 DAYS,
  61         [SCTP_CONNTRACK_SHUTDOWN_SENT]          = 300 SECS / 1000,
  62         [SCTP_CONNTRACK_SHUTDOWN_RECD]          = 300 SECS / 1000,
  63         [SCTP_CONNTRACK_SHUTDOWN_ACK_SENT]      = 3 SECS,
  64         [SCTP_CONNTRACK_HEARTBEAT_SENT]         = 30 SECS,
  65         [SCTP_CONNTRACK_HEARTBEAT_ACKED]        = 210 SECS,
  66 };
  67
  68 #define sNO SCTP_CONNTRACK_NONE
  69 #define sCL SCTP_CONNTRACK_CLOSED
  70 #define sCW SCTP_CONNTRACK_COOKIE_WAIT
  71 #define sCE SCTP_CONNTRACK_COOKIE_ECHOED
  72 #define sES SCTP_CONNTRACK_ESTABLISHED
  73 #define sSS SCTP_CONNTRACK_SHUTDOWN_SENT
  74 #define sSR SCTP_CONNTRACK_SHUTDOWN_RECD
  75 #define sSA SCTP_CONNTRACK_SHUTDOWN_ACK_SENT
  76 #define sHS SCTP_CONNTRACK_HEARTBEAT_SENT
  77 #define sHA SCTP_CONNTRACK_HEARTBEAT_ACKED
  78 #define sIV SCTP_CONNTRACK_MAX
  79
  80 /*
  81         These are the descriptions of the states:
  82
  83 NOTE: These state names are tantalizingly similar to the states of an
  84 SCTP endpoint. But the interpretation of the states is a little different,
  85 considering that these are the states of the connection and not of an end
  86 point. Please note the subtleties. -Kiran
  87
  88 NONE              - Nothing so far.
  89 COOKIE WAIT       - We have seen an INIT chunk in the original direction, or also
  90                     an INIT_ACK chunk in the reply direction.
  91 COOKIE ECHOED     - We have seen a COOKIE_ECHO chunk in the original direction.
  92 ESTABLISHED       - We have seen a COOKIE_ACK in the reply direction.
  93 SHUTDOWN_SENT     - We have seen a SHUTDOWN chunk in the original direction.
  94 SHUTDOWN_RECD     - We have seen a SHUTDOWN chunk in the reply directoin.
  95 SHUTDOWN_ACK_SENT - We have seen a SHUTDOWN_ACK chunk in the direction opposite
  96                     to that of the SHUTDOWN chunk.
  97 CLOSED            - We have seen a SHUTDOWN_COMPLETE chunk in the direction of
  98                     the SHUTDOWN chunk. Connection is closed.
  99 HEARTBEAT_SENT    - We have seen a HEARTBEAT in a new flow.
 100 HEARTBEAT_ACKED   - We have seen a HEARTBEAT-ACK in the direction opposite to
 101                     that of the HEARTBEAT chunk. Secondary connection is
 102                     established.
 103 */
 104
 105 /* TODO
 106  - I have assumed that the first INIT is in the original direction.
 107  This messes things when an INIT comes in the reply direction in CLOSED
 108  state.
 109  - Check the error type in the reply dir before transitioning from
 110 cookie echoed to closed.
 111  - Sec 5.2.4 of RFC 2960
 112  - Full Multi Homing support.
 113 */
 114
 115 /* SCTP conntrack state transitions */
 116 static const u8 sctp_conntracks[2][11][SCTP_CONNTRACK_MAX] = {
 117         {
 118 /*      ORIGINAL        */
 119 /*                  sNO, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS, sHA */
 120 /* init         */ {sCW, sCW, sCW, sCE, sES, sSS, sSR, sSA, sCW, sHA},
 121 /* init_ack     */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA, sCL, sHA},
 122 /* abort        */ {sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL},
 123 /* shutdown     */ {sCL, sCL, sCW, sCE, sSS, sSS, sSR, sSA, sCL, sSS},
 124 /* shutdown_ack */ {sSA, sCL, sCW, sCE, sES, sSA, sSA, sSA, sSA, sHA},
 125 /* error        */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA, sCL, sHA},/* Can't have Stale cookie*/
 126 /* cookie_echo  */ {sCL, sCL, sCE, sCE, sES, sSS, sSR, sSA, sCL, sHA},/* 5.2.4 - Big TODO */
 127 /* cookie_ack   */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA, sCL, sHA},/* Can't come in orig dir */
 128 /* shutdown_comp*/ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sCL, sCL, sHA},
 129 /* heartbeat    */ {sHS, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS, sHA},
 130 /* heartbeat_ack*/ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS, sHA}
 131         },
 132         {
 133 /*      REPLY   */
 134 /*                  sNO, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS, sHA */
 135 /* init         */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA, sIV, sHA},/* INIT in sCL Big TODO */
 136 /* init_ack     */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA, sIV, sHA},
 137 /* abort        */ {sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sIV, sCL},
 138 /* shutdown     */ {sIV, sCL, sCW, sCE, sSR, sSS, sSR, sSA, sIV, sSR},
 139 /* shutdown_ack */ {sIV, sCL, sCW, sCE, sES, sSA, sSA, sSA, sIV, sHA},
 140 /* error        */ {sIV, sCL, sCW, sCL, sES, sSS, sSR, sSA, sIV, sHA},
 141 /* cookie_echo  */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA, sIV, sHA},/* Can't come in reply dir */
 142 /* cookie_ack   */ {sIV, sCL, sCW, sES, sES, sSS, sSR, sSA, sIV, sHA},
 143 /* shutdown_comp*/ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sCL, sIV, sHA},
 144 /* heartbeat    */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS, sHA},
 145 /* heartbeat_ack*/ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHA, sHA}
 146         }
 147 };
 148
 149 static inline struct nf_sctp_net *sctp_pernet(struct net *net)
 150 {
 151         return &net->ct.nf_ct_proto.sctp;
 152 }
 153
 154 #ifdef CONFIG_NF_CONNTRACK_PROCFS
 155 /* Print out the private part of the conntrack. */
 156 static void sctp_print_conntrack(struct seq_file *s, struct nf_conn *ct)
 157 {
 158         seq_printf(s, "%s ", sctp_conntrack_names[ct->proto.sctp.state]);
 159 }
 160 #endif
 161
 162 #define for_each_sctp_chunk(skb, sch, _sch, offset, dataoff, count)     \
 163 for ((offset) = (dataoff) + sizeof(struct sctphdr), (count) = 0;        \
 164         (offset) < (skb)->len &&                                        \
 165         ((sch) = skb_header_pointer((skb), (offset), sizeof(_sch), &(_sch)));   \
 166         (offset) += (ntohs((sch)->length) + 3) & ~3, (count)++)
 167
 168 /* Some validity checks to make sure the chunks are fine */
 169 static int do_basic_checks(struct nf_conn *ct,
 170                            const struct sk_buff *skb,
 171                            unsigned int dataoff,
 172                            unsigned long *map)
 173 {
 174         u_int32_t offset, count;
 175         struct sctp_chunkhdr _sch, *sch;
 176         int flag;
 177
 178         flag = 0;
 179
 180         for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
 181                 pr_debug("Chunk Num: %d  Type: %d\n", count, sch->type);
 182
 183                 if (sch->type == SCTP_CID_INIT ||
 184                     sch->type == SCTP_CID_INIT_ACK ||
 185                     sch->type == SCTP_CID_SHUTDOWN_COMPLETE)
 186                         flag = 1;
 187
 188                 /*
 189                  * Cookie Ack/Echo chunks not the first OR
 190                  * Init / Init Ack / Shutdown compl chunks not the only chunks
 191                  * OR zero-length.
 192                  */
 193                 if (((sch->type == SCTP_CID_COOKIE_ACK ||
 194                       sch->type == SCTP_CID_COOKIE_ECHO ||
 195                       flag) &&
 196                      count != 0) || !sch->length) {
 197                         pr_debug("Basic checks failed\n");
 198                         return 1;
 199                 }
 200
 201                 if (map)
 202                         set_bit(sch->type, map);
 203         }
 204
 205         pr_debug("Basic checks passed\n");
 206         return count == 0;
 207 }
 208
 209 static int sctp_new_state(enum ip_conntrack_dir dir,
 210                           enum sctp_conntrack cur_state,
 211                           int chunk_type)
 212 {
 213         int i;
 214
 215         pr_debug("Chunk type: %d\n", chunk_type);
 216
 217         switch (chunk_type) {
 218         case SCTP_CID_INIT:
 219                 pr_debug("SCTP_CID_INIT\n");
 220                 i = 0;
 221                 break;
 222         case SCTP_CID_INIT_ACK:
 223                 pr_debug("SCTP_CID_INIT_ACK\n");
 224                 i = 1;
 225                 break;
 226         case SCTP_CID_ABORT:
 227                 pr_debug("SCTP_CID_ABORT\n");
 228                 i = 2;
 229                 break;
 230         case SCTP_CID_SHUTDOWN:
 231                 pr_debug("SCTP_CID_SHUTDOWN\n");
 232                 i = 3;
 233                 break;
 234         case SCTP_CID_SHUTDOWN_ACK:
 235                 pr_debug("SCTP_CID_SHUTDOWN_ACK\n");
 236                 i = 4;
 237                 break;
 238         case SCTP_CID_ERROR:
 239                 pr_debug("SCTP_CID_ERROR\n");
 240                 i = 5;
 241                 break;
 242         case SCTP_CID_COOKIE_ECHO:
 243                 pr_debug("SCTP_CID_COOKIE_ECHO\n");
 244                 i = 6;
 245                 break;
 246         case SCTP_CID_COOKIE_ACK:
 247                 pr_debug("SCTP_CID_COOKIE_ACK\n");
 248                 i = 7;
 249                 break;
 250         case SCTP_CID_SHUTDOWN_COMPLETE:
 251                 pr_debug("SCTP_CID_SHUTDOWN_COMPLETE\n");
 252                 i = 8;
 253                 break;
 254         case SCTP_CID_HEARTBEAT:
 255                 pr_debug("SCTP_CID_HEARTBEAT");
 256                 i = 9;
 257                 break;
 258         case SCTP_CID_HEARTBEAT_ACK:
 259                 pr_debug("SCTP_CID_HEARTBEAT_ACK");
 260                 i = 10;
 261                 break;
 262         default:
 263                 /* Other chunks like DATA or SACK do not change the state */
 264                 pr_debug("Unknown chunk type, Will stay in %s\n",
 265                          sctp_conntrack_names[cur_state]);
 266                 return cur_state;
 267         }
 268
 269         pr_debug("dir: %d   cur_state: %s  chunk_type: %d  new_state: %s\n",
 270                  dir, sctp_conntrack_names[cur_state], chunk_type,
 271                  sctp_conntrack_names[sctp_conntracks[dir][i][cur_state]]);
 272
 273         return sctp_conntracks[dir][i][cur_state];
 274 }
 275
 276 /* Returns verdict for packet, or -NF_ACCEPT for invalid. */
 277 static int sctp_packet(struct nf_conn *ct,
 278                        const struct sk_buff *skb,
 279                        unsigned int dataoff,
 280                        enum ip_conntrack_info ctinfo)
 281 {
 282         enum sctp_conntrack new_state, old_state;
 283         enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
 284         const struct sctphdr *sh;
 285         struct sctphdr _sctph;
 286         const struct sctp_chunkhdr *sch;
 287         struct sctp_chunkhdr _sch;
 288         u_int32_t offset, count;
 289         unsigned int *timeouts;
 290         unsigned long map[256 / sizeof(unsigned long)] = { 0 };
 291
 292         sh = skb_header_pointer(skb, dataoff, sizeof(_sctph), &_sctph);
 293         if (sh == NULL)
 294                 goto out;
 295
 296         if (do_basic_checks(ct, skb, dataoff, map) != 0)
 297                 goto out;
 298
 299         /* Check the verification tag (Sec 8.5) */
 300         if (!test_bit(SCTP_CID_INIT, map) &&
 301             !test_bit(SCTP_CID_SHUTDOWN_COMPLETE, map) &&
 302             !test_bit(SCTP_CID_COOKIE_ECHO, map) &&
 303             !test_bit(SCTP_CID_ABORT, map) &&
 304             !test_bit(SCTP_CID_SHUTDOWN_ACK, map) &&
 305             !test_bit(SCTP_CID_HEARTBEAT, map) &&
 306             !test_bit(SCTP_CID_HEARTBEAT_ACK, map) &&
 307             sh->vtag != ct->proto.sctp.vtag[dir]) {
 308                 pr_debug("Verification tag check failed\n");
 309                 goto out;
 310         }
 311
 312         old_state = new_state = SCTP_CONNTRACK_NONE;
 313         spin_lock_bh(&ct->lock);
 314         for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
 315                 /* Special cases of Verification tag check (Sec 8.5.1) */
 316                 if (sch->type == SCTP_CID_INIT) {
 317                         /* Sec 8.5.1 (A) */
 318                         if (sh->vtag != 0)
 319                                 goto out_unlock;
 320                 } else if (sch->type == SCTP_CID_ABORT) {
 321                         /* Sec 8.5.1 (B) */
 322                         if (sh->vtag != ct->proto.sctp.vtag[dir] &&
 323                             sh->vtag != ct->proto.sctp.vtag[!dir])
 324                                 goto out_unlock;
 325                 } else if (sch->type == SCTP_CID_SHUTDOWN_COMPLETE) {
 326                         /* Sec 8.5.1 (C) */
 327                         if (sh->vtag != ct->proto.sctp.vtag[dir] &&
 328                             sh->vtag != ct->proto.sctp.vtag[!dir] &&
 329                             sch->flags & SCTP_CHUNK_FLAG_T)
 330                                 goto out_unlock;
 331                 } else if (sch->type == SCTP_CID_COOKIE_ECHO) {
 332                         /* Sec 8.5.1 (D) */
 333                         if (sh->vtag != ct->proto.sctp.vtag[dir])
 334                                 goto out_unlock;
 335                 } else if (sch->type == SCTP_CID_HEARTBEAT ||
 336                            sch->type == SCTP_CID_HEARTBEAT_ACK) {
 337                         if (ct->proto.sctp.vtag[dir] == 0) {
 338                                 pr_debug("Setting vtag %x for dir %d\n",
 339                                          sh->vtag, dir);
 340                                 ct->proto.sctp.vtag[dir] = sh->vtag;
 341                         } else if (sh->vtag != ct->proto.sctp.vtag[dir]) {
 342                                 pr_debug("Verification tag check failed\n");
 343                                 goto out_unlock;
 344                         }
 345                 }
 346
 347                 old_state = ct->proto.sctp.state;
 348                 new_state = sctp_new_state(dir, old_state, sch->type);
 349
 350                 /* Invalid */
 351                 if (new_state == SCTP_CONNTRACK_MAX) {
 352                         pr_debug("nf_conntrack_sctp: Invalid dir=%i ctype=%u "
 353                                  "conntrack=%u\n",
 354                                  dir, sch->type, old_state);
 355                         goto out_unlock;
 356                 }
 357
 358                 /* If it is an INIT or an INIT ACK note down the vtag */
 359                 if (sch->type == SCTP_CID_INIT ||
 360                     sch->type == SCTP_CID_INIT_ACK) {
 361                         struct sctp_inithdr _inithdr, *ih;
 362
 363                         ih = skb_header_pointer(skb, offset + sizeof(_sch),
 364                                                 sizeof(_inithdr), &_inithdr);
 365                         if (ih == NULL)
 366                                 goto out_unlock;
 367                         pr_debug("Setting vtag %x for dir %d\n",
 368                                  ih->init_tag, !dir);
 369                         ct->proto.sctp.vtag[!dir] = ih->init_tag;
 370                 }
 371
 372                 ct->proto.sctp.state = new_state;
 373                 if (old_state != new_state)
 374                         nf_conntrack_event_cache(IPCT_PROTOINFO, ct);
 375         }
 376         spin_unlock_bh(&ct->lock);
 377
 378         timeouts = nf_ct_timeout_lookup(ct);
 379         if (!timeouts)
 380                 timeouts = sctp_pernet(nf_ct_net(ct))->timeouts;
 381
 382         nf_ct_refresh_acct(ct, ctinfo, skb, timeouts[new_state]);
 383
 384         if (old_state == SCTP_CONNTRACK_COOKIE_ECHOED &&
 385             dir == IP_CT_DIR_REPLY &&
 386             new_state == SCTP_CONNTRACK_ESTABLISHED) {
 387                 pr_debug("Setting assured bit\n");
 388                 set_bit(IPS_ASSURED_BIT, &ct->status);
 389                 nf_conntrack_event_cache(IPCT_ASSURED, ct);
 390         }
 391
 392         return NF_ACCEPT;
 393
 394 out_unlock:
 395         spin_unlock_bh(&ct->lock);
 396 out:
 397         return -NF_ACCEPT;
 398 }
 399
 400 /* Called when a new connection for this protocol found. */
 401 static bool sctp_new(struct nf_conn *ct, const struct sk_buff *skb,
 402                      unsigned int dataoff)
 403 {
 404         enum sctp_conntrack new_state;
 405         const struct sctphdr *sh;
 406         struct sctphdr _sctph;
 407         const struct sctp_chunkhdr *sch;
 408         struct sctp_chunkhdr _sch;
 409         u_int32_t offset, count;
 410         unsigned long map[256 / sizeof(unsigned long)] = { 0 };
 411
 412         sh = skb_header_pointer(skb, dataoff, sizeof(_sctph), &_sctph);
 413         if (sh == NULL)
 414                 return false;
 415
 416         if (do_basic_checks(ct, skb, dataoff, map) != 0)
 417                 return false;
 418
 419         /* If an OOTB packet has any of these chunks discard (Sec 8.4) */
 420         if (test_bit(SCTP_CID_ABORT, map) ||
 421             test_bit(SCTP_CID_SHUTDOWN_COMPLETE, map) ||
 422             test_bit(SCTP_CID_COOKIE_ACK, map))
 423                 return false;
 424
 425         memset(&ct->proto.sctp, 0, sizeof(ct->proto.sctp));
 426         new_state = SCTP_CONNTRACK_MAX;
 427         for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
 428                 /* Don't need lock here: this conntrack not in circulation yet */
 429                 new_state = sctp_new_state(IP_CT_DIR_ORIGINAL,
 430                                            SCTP_CONNTRACK_NONE, sch->type);
 431
 432                 /* Invalid: delete conntrack */
 433                 if (new_state == SCTP_CONNTRACK_NONE ||
 434                     new_state == SCTP_CONNTRACK_MAX) {
 435                         pr_debug("nf_conntrack_sctp: invalid new deleting.\n");
 436                         return false;
 437                 }
 438
 439                 /* Copy the vtag into the state info */
 440                 if (sch->type == SCTP_CID_INIT) {
 441                         struct sctp_inithdr _inithdr, *ih;
 442                         /* Sec 8.5.1 (A) */
 443                         if (sh->vtag)
 444                                 return false;
 445
 446                         ih = skb_header_pointer(skb, offset + sizeof(_sch),
 447                                                 sizeof(_inithdr), &_inithdr);
 448                         if (!ih)
 449                                 return false;
 450
 451                         pr_debug("Setting vtag %x for new conn\n",
 452                                  ih->init_tag);
 453
 454                         ct->proto.sctp.vtag[IP_CT_DIR_REPLY] = ih->init_tag;
 455                 } else if (sch->type == SCTP_CID_HEARTBEAT) {
 456                         pr_debug("Setting vtag %x for secondary conntrack\n",
 457                                  sh->vtag);
 458                         ct->proto.sctp.vtag[IP_CT_DIR_ORIGINAL] = sh->vtag;
 459                 }
 460                 /* If it is a shutdown ack OOTB packet, we expect a return
 461                    shutdown complete, otherwise an ABORT Sec 8.4 (5) and (8) */
 462                 else {
 463                         pr_debug("Setting vtag %x for new conn OOTB\n",
 464                                  sh->vtag);
 465                         ct->proto.sctp.vtag[IP_CT_DIR_REPLY] = sh->vtag;
 466                 }
 467
 468                 ct->proto.sctp.state = new_state;
 469         }
 470
 471         return true;
 472 }
 473
 474 static int sctp_error(struct net *net, struct nf_conn *tpl, struct sk_buff *skb,
 475                       unsigned int dataoff,
 476                       u8 pf, unsigned int hooknum)
 477 {
 478         const struct sctphdr *sh;
 479         const char *logmsg;
 480
 481         if (skb->len < dataoff + sizeof(struct sctphdr)) {
 482                 logmsg = "nf_ct_sctp: short packet ";
 483                 goto out_invalid;
 484         }
 485         if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
 486             skb->ip_summed == CHECKSUM_NONE) {
 487                 if (!skb_make_writable(skb, dataoff + sizeof(struct sctphdr))) {
 488                         logmsg = "nf_ct_sctp: failed to read header ";
 489                         goto out_invalid;
 490                 }
 491                 sh = (const struct sctphdr *)(skb->data + dataoff);
 492                 if (sh->checksum != sctp_compute_cksum(skb, dataoff)) {
 493                         logmsg = "nf_ct_sctp: bad CRC ";
 494                         goto out_invalid;
 495                 }
 496                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 497         }
 498         return NF_ACCEPT;
 499 out_invalid:
 500         nf_l4proto_log_invalid(skb, net, pf, IPPROTO_SCTP, "%s", logmsg);
 501         return -NF_ACCEPT;
 502 }
 503
 504 static bool sctp_can_early_drop(const struct nf_conn *ct)
 505 {
 506         switch (ct->proto.sctp.state) {
 507         case SCTP_CONNTRACK_SHUTDOWN_SENT:
 508         case SCTP_CONNTRACK_SHUTDOWN_RECD:
 509         case SCTP_CONNTRACK_SHUTDOWN_ACK_SENT:
 510                 return true;
 511         default:
 512                 break;
 513         }
 514
 515         return false;
 516 }
 517
 518 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 519
 520 #include <linux/netfilter/nfnetlink.h>
 521 #include <linux/netfilter/nfnetlink_conntrack.h>
 522
 523 static int sctp_to_nlattr(struct sk_buff *skb, struct nlattr *nla,
 524                           struct nf_conn *ct)
 525 {
 526         struct nlattr *nest_parms;
 527
 528         spin_lock_bh(&ct->lock);
 529         nest_parms = nla_nest_start(skb, CTA_PROTOINFO_SCTP | NLA_F_NESTED);
 530         if (!nest_parms)
 531                 goto nla_put_failure;
 532
 533         if (nla_put_u8(skb, CTA_PROTOINFO_SCTP_STATE, ct->proto.sctp.state) ||
 534             nla_put_be32(skb, CTA_PROTOINFO_SCTP_VTAG_ORIGINAL,
 535                          ct->proto.sctp.vtag[IP_CT_DIR_ORIGINAL]) ||
 536             nla_put_be32(skb, CTA_PROTOINFO_SCTP_VTAG_REPLY,
 537                          ct->proto.sctp.vtag[IP_CT_DIR_REPLY]))
 538                 goto nla_put_failure;
 539
 540         spin_unlock_bh(&ct->lock);
 541
 542         nla_nest_end(skb, nest_parms);
 543
 544         return 0;
 545
 546 nla_put_failure:
 547         spin_unlock_bh(&ct->lock);
 548         return -1;
 549 }
 550
 551 static const struct nla_policy sctp_nla_policy[CTA_PROTOINFO_SCTP_MAX+1] = {
 552         [CTA_PROTOINFO_SCTP_STATE]          = { .type = NLA_U8 },
 553         [CTA_PROTOINFO_SCTP_VTAG_ORIGINAL]  = { .type = NLA_U32 },
 554         [CTA_PROTOINFO_SCTP_VTAG_REPLY]     = { .type = NLA_U32 },
 555 };
 556
 557 #define SCTP_NLATTR_SIZE ( \
 558                 NLA_ALIGN(NLA_HDRLEN + 1) + \
 559                 NLA_ALIGN(NLA_HDRLEN + 4) + \
 560                 NLA_ALIGN(NLA_HDRLEN + 4))
 561
 562 static int nlattr_to_sctp(struct nlattr *cda[], struct nf_conn *ct)
 563 {
 564         struct nlattr *attr = cda[CTA_PROTOINFO_SCTP];
 565         struct nlattr *tb[CTA_PROTOINFO_SCTP_MAX+1];
 566         int err;
 567
 568         /* updates may not contain the internal protocol info, skip parsing */
 569         if (!attr)
 570                 return 0;
 571
 572         err = nla_parse_nested(tb, CTA_PROTOINFO_SCTP_MAX, attr,
 573                                sctp_nla_policy, NULL);
 574         if (err < 0)
 575                 return err;
 576
 577         if (!tb[CTA_PROTOINFO_SCTP_STATE] ||
 578             !tb[CTA_PROTOINFO_SCTP_VTAG_ORIGINAL] ||
 579             !tb[CTA_PROTOINFO_SCTP_VTAG_REPLY])
 580                 return -EINVAL;
 581
 582         spin_lock_bh(&ct->lock);
 583         ct->proto.sctp.state = nla_get_u8(tb[CTA_PROTOINFO_SCTP_STATE]);
 584         ct->proto.sctp.vtag[IP_CT_DIR_ORIGINAL] =
 585                 nla_get_be32(tb[CTA_PROTOINFO_SCTP_VTAG_ORIGINAL]);
 586         ct->proto.sctp.vtag[IP_CT_DIR_REPLY] =
 587                 nla_get_be32(tb[CTA_PROTOINFO_SCTP_VTAG_REPLY]);
 588         spin_unlock_bh(&ct->lock);
 589
 590         return 0;
 591 }
 592 #endif
 593
 594 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
 595
 596 #include <linux/netfilter/nfnetlink.h>
 597 #include <linux/netfilter/nfnetlink_cttimeout.h>
 598
 599 static int sctp_timeout_nlattr_to_obj(struct nlattr *tb[],
 600                                       struct net *net, void *data)
 601 {
 602         unsigned int *timeouts = data;
 603         struct nf_sctp_net *sn = sctp_pernet(net);
 604         int i;
 605
 606         /* set default SCTP timeouts. */
 607         for (i=0; i<SCTP_CONNTRACK_MAX; i++)
 608                 timeouts[i] = sn->timeouts[i];
 609
 610         /* there's a 1:1 mapping between attributes and protocol states. */
 611         for (i=CTA_TIMEOUT_SCTP_UNSPEC+1; i<CTA_TIMEOUT_SCTP_MAX+1; i++) {
 612                 if (tb[i]) {
 613                         timeouts[i] = ntohl(nla_get_be32(tb[i])) * HZ;
 614                 }
 615         }
 616         return 0;
 617 }
 618
 619 static int
 620 sctp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
 621 {
 622         const unsigned int *timeouts = data;
 623         int i;
 624
 625         for (i=CTA_TIMEOUT_SCTP_UNSPEC+1; i<CTA_TIMEOUT_SCTP_MAX+1; i++) {
 626                 if (nla_put_be32(skb, i, htonl(timeouts[i] / HZ)))
 627                         goto nla_put_failure;
 628         }
 629         return 0;
 630
 631 nla_put_failure:
 632         return -ENOSPC;
 633 }
 634
 635 static const struct nla_policy
 636 sctp_timeout_nla_policy[CTA_TIMEOUT_SCTP_MAX+1] = {
 637         [CTA_TIMEOUT_SCTP_CLOSED]               = { .type = NLA_U32 },
 638         [CTA_TIMEOUT_SCTP_COOKIE_WAIT]          = { .type = NLA_U32 },
 639         [CTA_TIMEOUT_SCTP_COOKIE_ECHOED]        = { .type = NLA_U32 },
 640         [CTA_TIMEOUT_SCTP_ESTABLISHED]          = { .type = NLA_U32 },
 641         [CTA_TIMEOUT_SCTP_SHUTDOWN_SENT]        = { .type = NLA_U32 },
 642         [CTA_TIMEOUT_SCTP_SHUTDOWN_RECD]        = { .type = NLA_U32 },
 643         [CTA_TIMEOUT_SCTP_SHUTDOWN_ACK_SENT]    = { .type = NLA_U32 },
 644         [CTA_TIMEOUT_SCTP_HEARTBEAT_SENT]       = { .type = NLA_U32 },
 645         [CTA_TIMEOUT_SCTP_HEARTBEAT_ACKED]      = { .type = NLA_U32 },
 646 };
 647 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 648
 649
 650 #ifdef CONFIG_SYSCTL
 651 static struct ctl_table sctp_sysctl_table[] = {
 652         {
 653                 .procname       = "nf_conntrack_sctp_timeout_closed",
 654                 .maxlen         = sizeof(unsigned int),
 655                 .mode           = 0644,
 656                 .proc_handler   = proc_dointvec_jiffies,
 657         },
 658         {
 659                 .procname       = "nf_conntrack_sctp_timeout_cookie_wait",
 660                 .maxlen         = sizeof(unsigned int),
 661                 .mode           = 0644,
 662                 .proc_handler   = proc_dointvec_jiffies,
 663         },
 664         {
 665                 .procname       = "nf_conntrack_sctp_timeout_cookie_echoed",
 666                 .maxlen         = sizeof(unsigned int),
 667                 .mode           = 0644,
 668                 .proc_handler   = proc_dointvec_jiffies,
 669         },
 670         {
 671                 .procname       = "nf_conntrack_sctp_timeout_established",
 672                 .maxlen         = sizeof(unsigned int),
 673                 .mode           = 0644,
 674                 .proc_handler   = proc_dointvec_jiffies,
 675         },
 676         {
 677                 .procname       = "nf_conntrack_sctp_timeout_shutdown_sent",
 678                 .maxlen         = sizeof(unsigned int),
 679                 .mode           = 0644,
 680                 .proc_handler   = proc_dointvec_jiffies,
 681         },
 682         {
 683                 .procname       = "nf_conntrack_sctp_timeout_shutdown_recd",
 684                 .maxlen         = sizeof(unsigned int),
 685                 .mode           = 0644,
 686                 .proc_handler   = proc_dointvec_jiffies,
 687         },
 688         {
 689                 .procname       = "nf_conntrack_sctp_timeout_shutdown_ack_sent",
 690                 .maxlen         = sizeof(unsigned int),
 691                 .mode           = 0644,
 692                 .proc_handler   = proc_dointvec_jiffies,
 693         },
 694         {
 695                 .procname       = "nf_conntrack_sctp_timeout_heartbeat_sent",
 696                 .maxlen         = sizeof(unsigned int),
 697                 .mode           = 0644,
 698                 .proc_handler   = proc_dointvec_jiffies,
 699         },
 700         {
 701                 .procname       = "nf_conntrack_sctp_timeout_heartbeat_acked",
 702                 .maxlen         = sizeof(unsigned int),
 703                 .mode           = 0644,
 704                 .proc_handler   = proc_dointvec_jiffies,
 705         },
 706         { }
 707 };
 708 #endif
 709
 710 static int sctp_kmemdup_sysctl_table(struct nf_proto_net *pn,
 711                                      struct nf_sctp_net *sn)
 712 {
 713 #ifdef CONFIG_SYSCTL
 714         if (pn->ctl_table)
 715                 return 0;
 716
 717         pn->ctl_table = kmemdup(sctp_sysctl_table,
 718                                 sizeof(sctp_sysctl_table),
 719                                 GFP_KERNEL);
 720         if (!pn->ctl_table)
 721                 return -ENOMEM;
 722
 723         pn->ctl_table[0].data = &sn->timeouts[SCTP_CONNTRACK_CLOSED];
 724         pn->ctl_table[1].data = &sn->timeouts[SCTP_CONNTRACK_COOKIE_WAIT];
 725         pn->ctl_table[2].data = &sn->timeouts[SCTP_CONNTRACK_COOKIE_ECHOED];
 726         pn->ctl_table[3].data = &sn->timeouts[SCTP_CONNTRACK_ESTABLISHED];
 727         pn->ctl_table[4].data = &sn->timeouts[SCTP_CONNTRACK_SHUTDOWN_SENT];
 728         pn->ctl_table[5].data = &sn->timeouts[SCTP_CONNTRACK_SHUTDOWN_RECD];
 729         pn->ctl_table[6].data = &sn->timeouts[SCTP_CONNTRACK_SHUTDOWN_ACK_SENT];
 730         pn->ctl_table[7].data = &sn->timeouts[SCTP_CONNTRACK_HEARTBEAT_SENT];
 731         pn->ctl_table[8].data = &sn->timeouts[SCTP_CONNTRACK_HEARTBEAT_ACKED];
 732 #endif
 733         return 0;
 734 }
 735
 736 static int sctp_init_net(struct net *net, u_int16_t proto)
 737 {
 738         struct nf_sctp_net *sn = sctp_pernet(net);
 739         struct nf_proto_net *pn = &sn->pn;
 740
 741         if (!pn->users) {
 742                 int i;
 743
 744                 for (i = 0; i < SCTP_CONNTRACK_MAX; i++)
 745                         sn->timeouts[i] = sctp_timeouts[i];
 746         }
 747
 748         return sctp_kmemdup_sysctl_table(pn, sn);
 749 }
 750
 751 static struct nf_proto_net *sctp_get_net_proto(struct net *net)
 752 {
 753         return &net->ct.nf_ct_proto.sctp.pn;
 754 }
 755
 756 const struct nf_conntrack_l4proto nf_conntrack_l4proto_sctp4 = {
 757         .l3proto                = PF_INET,
 758         .l4proto                = IPPROTO_SCTP,
 759 #ifdef CONFIG_NF_CONNTRACK_PROCFS
 760         .print_conntrack        = sctp_print_conntrack,
 761 #endif
 762         .packet                 = sctp_packet,
 763         .new                    = sctp_new,
 764         .error                  = sctp_error,
 765         .can_early_drop         = sctp_can_early_drop,
 766         .me                     = THIS_MODULE,
 767 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 768         .nlattr_size            = SCTP_NLATTR_SIZE,
 769         .to_nlattr              = sctp_to_nlattr,
 770         .from_nlattr            = nlattr_to_sctp,
 771         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
 772         .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
 773         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
 774         .nla_policy             = nf_ct_port_nla_policy,
 775 #endif
 776 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
 777         .ctnl_timeout           = {
 778                 .nlattr_to_obj  = sctp_timeout_nlattr_to_obj,
 779                 .obj_to_nlattr  = sctp_timeout_obj_to_nlattr,
 780                 .nlattr_max     = CTA_TIMEOUT_SCTP_MAX,
 781                 .obj_size       = sizeof(unsigned int) * SCTP_CONNTRACK_MAX,
 782                 .nla_policy     = sctp_timeout_nla_policy,
 783         },
 784 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 785         .init_net               = sctp_init_net,
 786         .get_net_proto          = sctp_get_net_proto,
 787 };
 788 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_sctp4);
 789
 790 const struct nf_conntrack_l4proto nf_conntrack_l4proto_sctp6 = {
 791         .l3proto                = PF_INET6,
 792         .l4proto                = IPPROTO_SCTP,
 793 #ifdef CONFIG_NF_CONNTRACK_PROCFS
 794         .print_conntrack        = sctp_print_conntrack,
 795 #endif
 796         .packet                 = sctp_packet,
 797         .new                    = sctp_new,
 798         .error                  = sctp_error,
 799         .can_early_drop         = sctp_can_early_drop,
 800         .me                     = THIS_MODULE,
 801 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 802         .nlattr_size            = SCTP_NLATTR_SIZE,
 803         .to_nlattr              = sctp_to_nlattr,
 804         .from_nlattr            = nlattr_to_sctp,
 805         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
 806         .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
 807         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
 808         .nla_policy             = nf_ct_port_nla_policy,
 809 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
 810         .ctnl_timeout           = {
 811                 .nlattr_to_obj  = sctp_timeout_nlattr_to_obj,
 812                 .obj_to_nlattr  = sctp_timeout_obj_to_nlattr,
 813                 .nlattr_max     = CTA_TIMEOUT_SCTP_MAX,
 814                 .obj_size       = sizeof(unsigned int) * SCTP_CONNTRACK_MAX,
 815                 .nla_policy     = sctp_timeout_nla_policy,
 816         },
 817 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 818 #endif
 819         .init_net               = sctp_init_net,
 820         .get_net_proto          = sctp_get_net_proto,
 821 };
 822 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_sctp6);