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
  32 /* FIXME: Examine ipfilter's timeouts and conntrack transitions more
  33    closely.  They're more complex. --RR
  34
  35    And so for me for SCTP :D -Kiran */
  36
  37 static const char *const sctp_conntrack_names[] = {
  38         "NONE",
  39         "CLOSED",
  40         "COOKIE_WAIT",
  41         "COOKIE_ECHOED",
  42         "ESTABLISHED",
  43         "SHUTDOWN_SENT",
  44         "SHUTDOWN_RECD",
  45         "SHUTDOWN_ACK_SENT",
  46         "HEARTBEAT_SENT",
  47         "HEARTBEAT_ACKED",
  48 };
  49
  50 #define SECS  * HZ
  51 #define MINS  * 60 SECS
  52 #define HOURS * 60 MINS
  53 #define DAYS  * 24 HOURS
  54
  55 static const unsigned int sctp_timeouts[SCTP_CONNTRACK_MAX] = {
  56         [SCTP_CONNTRACK_CLOSED]                 = 10 SECS,
  57         [SCTP_CONNTRACK_COOKIE_WAIT]            = 3 SECS,
  58         [SCTP_CONNTRACK_COOKIE_ECHOED]          = 3 SECS,
  59         [SCTP_CONNTRACK_ESTABLISHED]            = 5 DAYS,
  60         [SCTP_CONNTRACK_SHUTDOWN_SENT]          = 300 SECS / 1000,
  61         [SCTP_CONNTRACK_SHUTDOWN_RECD]          = 300 SECS / 1000,
  62         [SCTP_CONNTRACK_SHUTDOWN_ACK_SENT]      = 3 SECS,
  63         [SCTP_CONNTRACK_HEARTBEAT_SENT]         = 30 SECS,
  64         [SCTP_CONNTRACK_HEARTBEAT_ACKED]        = 210 SECS,
  65 };
  66
  67 #define sNO SCTP_CONNTRACK_NONE
  68 #define sCL SCTP_CONNTRACK_CLOSED
  69 #define sCW SCTP_CONNTRACK_COOKIE_WAIT
  70 #define sCE SCTP_CONNTRACK_COOKIE_ECHOED
  71 #define sES SCTP_CONNTRACK_ESTABLISHED
  72 #define sSS SCTP_CONNTRACK_SHUTDOWN_SENT
  73 #define sSR SCTP_CONNTRACK_SHUTDOWN_RECD
  74 #define sSA SCTP_CONNTRACK_SHUTDOWN_ACK_SENT
  75 #define sHS SCTP_CONNTRACK_HEARTBEAT_SENT
  76 #define sHA SCTP_CONNTRACK_HEARTBEAT_ACKED
  77 #define sIV SCTP_CONNTRACK_MAX
  78
  79 /*
  80         These are the descriptions of the states:
  81
  82 NOTE: These state names are tantalizingly similar to the states of an
  83 SCTP endpoint. But the interpretation of the states is a little different,
  84 considering that these are the states of the connection and not of an end
  85 point. Please note the subtleties. -Kiran
  86
  87 NONE              - Nothing so far.
  88 COOKIE WAIT       - We have seen an INIT chunk in the original direction, or also
  89                     an INIT_ACK chunk in the reply direction.
  90 COOKIE ECHOED     - We have seen a COOKIE_ECHO chunk in the original direction.
  91 ESTABLISHED       - We have seen a COOKIE_ACK in the reply direction.
  92 SHUTDOWN_SENT     - We have seen a SHUTDOWN chunk in the original direction.
  93 SHUTDOWN_RECD     - We have seen a SHUTDOWN chunk in the reply directoin.
  94 SHUTDOWN_ACK_SENT - We have seen a SHUTDOWN_ACK chunk in the direction opposite
  95                     to that of the SHUTDOWN chunk.
  96 CLOSED            - We have seen a SHUTDOWN_COMPLETE chunk in the direction of
  97                     the SHUTDOWN chunk. Connection is closed.
  98 HEARTBEAT_SENT    - We have seen a HEARTBEAT in a new flow.
  99 HEARTBEAT_ACKED   - We have seen a HEARTBEAT-ACK in the direction opposite to
 100                     that of the HEARTBEAT chunk. Secondary connection is
 101                     established.
 102 */
 103
 104 /* TODO
 105  - I have assumed that the first INIT is in the original direction.
 106  This messes things when an INIT comes in the reply direction in CLOSED
 107  state.
 108  - Check the error type in the reply dir before transitioning from
 109 cookie echoed to closed.
 110  - Sec 5.2.4 of RFC 2960
 111  - Full Multi Homing support.
 112 */
 113
 114 /* SCTP conntrack state transitions */
 115 static const u8 sctp_conntracks[2][11][SCTP_CONNTRACK_MAX] = {
 116         {
 117 /*      ORIGINAL        */
 118 /*                  sNO, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS, sHA */
 119 /* init         */ {sCW, sCW, sCW, sCE, sES, sSS, sSR, sSA, sCW, sHA},
 120 /* init_ack     */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA, sCL, sHA},
 121 /* abort        */ {sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL},
 122 /* shutdown     */ {sCL, sCL, sCW, sCE, sSS, sSS, sSR, sSA, sCL, sSS},
 123 /* shutdown_ack */ {sSA, sCL, sCW, sCE, sES, sSA, sSA, sSA, sSA, sHA},
 124 /* error        */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA, sCL, sHA},/* Can't have Stale cookie*/
 125 /* cookie_echo  */ {sCL, sCL, sCE, sCE, sES, sSS, sSR, sSA, sCL, sHA},/* 5.2.4 - Big TODO */
 126 /* cookie_ack   */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA, sCL, sHA},/* Can't come in orig dir */
 127 /* shutdown_comp*/ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sCL, sCL, sHA},
 128 /* heartbeat    */ {sHS, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS, sHA},
 129 /* heartbeat_ack*/ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS, sHA}
 130         },
 131         {
 132 /*      REPLY   */
 133 /*                  sNO, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS, sHA */
 134 /* init         */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA, sIV, sHA},/* INIT in sCL Big TODO */
 135 /* init_ack     */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA, sIV, sHA},
 136 /* abort        */ {sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sIV, sCL},
 137 /* shutdown     */ {sIV, sCL, sCW, sCE, sSR, sSS, sSR, sSA, sIV, sSR},
 138 /* shutdown_ack */ {sIV, sCL, sCW, sCE, sES, sSA, sSA, sSA, sIV, sHA},
 139 /* error        */ {sIV, sCL, sCW, sCL, sES, sSS, sSR, sSA, sIV, sHA},
 140 /* cookie_echo  */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA, sIV, sHA},/* Can't come in reply dir */
 141 /* cookie_ack   */ {sIV, sCL, sCW, sES, sES, sSS, sSR, sSA, sIV, sHA},
 142 /* shutdown_comp*/ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sCL, sIV, sHA},
 143 /* heartbeat    */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS, sHA},
 144 /* heartbeat_ack*/ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHA, sHA}
 145         }
 146 };
 147
 148 static inline struct nf_sctp_net *sctp_pernet(struct net *net)
 149 {
 150         return &net->ct.nf_ct_proto.sctp;
 151 }
 152
 153 static bool sctp_pkt_to_tuple(const struct sk_buff *skb, unsigned int dataoff,
 154                               struct net *net, struct nf_conntrack_tuple *tuple)
 155 {
 156         const struct sctphdr *hp;
 157         struct sctphdr _hdr;
 158
 159         /* Actually only need first 4 bytes to get ports. */
 160         hp = skb_header_pointer(skb, dataoff, 4, &_hdr);
 161         if (hp == NULL)
 162                 return false;
 163
 164         tuple->src.u.sctp.port = hp->source;
 165         tuple->dst.u.sctp.port = hp->dest;
 166         return true;
 167 }
 168
 169 static bool sctp_invert_tuple(struct nf_conntrack_tuple *tuple,
 170                               const struct nf_conntrack_tuple *orig)
 171 {
 172         tuple->src.u.sctp.port = orig->dst.u.sctp.port;
 173         tuple->dst.u.sctp.port = orig->src.u.sctp.port;
 174         return true;
 175 }
 176
 177 #ifdef CONFIG_NF_CONNTRACK_PROCFS
 178 /* Print out the private part of the conntrack. */
 179 static void sctp_print_conntrack(struct seq_file *s, struct nf_conn *ct)
 180 {
 181         seq_printf(s, "%s ", sctp_conntrack_names[ct->proto.sctp.state]);
 182 }
 183 #endif
 184
 185 #define for_each_sctp_chunk(skb, sch, _sch, offset, dataoff, count)     \
 186 for ((offset) = (dataoff) + sizeof(struct sctphdr), (count) = 0;        \
 187         (offset) < (skb)->len &&                                        \
 188         ((sch) = skb_header_pointer((skb), (offset), sizeof(_sch), &(_sch)));   \
 189         (offset) += (ntohs((sch)->length) + 3) & ~3, (count)++)
 190
 191 /* Some validity checks to make sure the chunks are fine */
 192 static int do_basic_checks(struct nf_conn *ct,
 193                            const struct sk_buff *skb,
 194                            unsigned int dataoff,
 195                            unsigned long *map)
 196 {
 197         u_int32_t offset, count;
 198         struct sctp_chunkhdr _sch, *sch;
 199         int flag;
 200
 201         flag = 0;
 202
 203         for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
 204                 pr_debug("Chunk Num: %d  Type: %d\n", count, sch->type);
 205
 206                 if (sch->type == SCTP_CID_INIT ||
 207                     sch->type == SCTP_CID_INIT_ACK ||
 208                     sch->type == SCTP_CID_SHUTDOWN_COMPLETE)
 209                         flag = 1;
 210
 211                 /*
 212                  * Cookie Ack/Echo chunks not the first OR
 213                  * Init / Init Ack / Shutdown compl chunks not the only chunks
 214                  * OR zero-length.
 215                  */
 216                 if (((sch->type == SCTP_CID_COOKIE_ACK ||
 217                       sch->type == SCTP_CID_COOKIE_ECHO ||
 218                       flag) &&
 219                      count != 0) || !sch->length) {
 220                         pr_debug("Basic checks failed\n");
 221                         return 1;
 222                 }
 223
 224                 if (map)
 225                         set_bit(sch->type, map);
 226         }
 227
 228         pr_debug("Basic checks passed\n");
 229         return count == 0;
 230 }
 231
 232 static int sctp_new_state(enum ip_conntrack_dir dir,
 233                           enum sctp_conntrack cur_state,
 234                           int chunk_type)
 235 {
 236         int i;
 237
 238         pr_debug("Chunk type: %d\n", chunk_type);
 239
 240         switch (chunk_type) {
 241         case SCTP_CID_INIT:
 242                 pr_debug("SCTP_CID_INIT\n");
 243                 i = 0;
 244                 break;
 245         case SCTP_CID_INIT_ACK:
 246                 pr_debug("SCTP_CID_INIT_ACK\n");
 247                 i = 1;
 248                 break;
 249         case SCTP_CID_ABORT:
 250                 pr_debug("SCTP_CID_ABORT\n");
 251                 i = 2;
 252                 break;
 253         case SCTP_CID_SHUTDOWN:
 254                 pr_debug("SCTP_CID_SHUTDOWN\n");
 255                 i = 3;
 256                 break;
 257         case SCTP_CID_SHUTDOWN_ACK:
 258                 pr_debug("SCTP_CID_SHUTDOWN_ACK\n");
 259                 i = 4;
 260                 break;
 261         case SCTP_CID_ERROR:
 262                 pr_debug("SCTP_CID_ERROR\n");
 263                 i = 5;
 264                 break;
 265         case SCTP_CID_COOKIE_ECHO:
 266                 pr_debug("SCTP_CID_COOKIE_ECHO\n");
 267                 i = 6;
 268                 break;
 269         case SCTP_CID_COOKIE_ACK:
 270                 pr_debug("SCTP_CID_COOKIE_ACK\n");
 271                 i = 7;
 272                 break;
 273         case SCTP_CID_SHUTDOWN_COMPLETE:
 274                 pr_debug("SCTP_CID_SHUTDOWN_COMPLETE\n");
 275                 i = 8;
 276                 break;
 277         case SCTP_CID_HEARTBEAT:
 278                 pr_debug("SCTP_CID_HEARTBEAT");
 279                 i = 9;
 280                 break;
 281         case SCTP_CID_HEARTBEAT_ACK:
 282                 pr_debug("SCTP_CID_HEARTBEAT_ACK");
 283                 i = 10;
 284                 break;
 285         default:
 286                 /* Other chunks like DATA or SACK do not change the state */
 287                 pr_debug("Unknown chunk type, Will stay in %s\n",
 288                          sctp_conntrack_names[cur_state]);
 289                 return cur_state;
 290         }
 291
 292         pr_debug("dir: %d   cur_state: %s  chunk_type: %d  new_state: %s\n",
 293                  dir, sctp_conntrack_names[cur_state], chunk_type,
 294                  sctp_conntrack_names[sctp_conntracks[dir][i][cur_state]]);
 295
 296         return sctp_conntracks[dir][i][cur_state];
 297 }
 298
 299 static unsigned int *sctp_get_timeouts(struct net *net)
 300 {
 301         return sctp_pernet(net)->timeouts;
 302 }
 303
 304 /* Returns verdict for packet, or -NF_ACCEPT for invalid. */
 305 static int sctp_packet(struct nf_conn *ct,
 306                        const struct sk_buff *skb,
 307                        unsigned int dataoff,
 308                        enum ip_conntrack_info ctinfo,
 309                        unsigned int *timeouts)
 310 {
 311         enum sctp_conntrack new_state, old_state;
 312         enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
 313         const struct sctphdr *sh;
 314         struct sctphdr _sctph;
 315         const struct sctp_chunkhdr *sch;
 316         struct sctp_chunkhdr _sch;
 317         u_int32_t offset, count;
 318         unsigned long map[256 / sizeof(unsigned long)] = { 0 };
 319
 320         sh = skb_header_pointer(skb, dataoff, sizeof(_sctph), &_sctph);
 321         if (sh == NULL)
 322                 goto out;
 323
 324         if (do_basic_checks(ct, skb, dataoff, map) != 0)
 325                 goto out;
 326
 327         /* Check the verification tag (Sec 8.5) */
 328         if (!test_bit(SCTP_CID_INIT, map) &&
 329             !test_bit(SCTP_CID_SHUTDOWN_COMPLETE, map) &&
 330             !test_bit(SCTP_CID_COOKIE_ECHO, map) &&
 331             !test_bit(SCTP_CID_ABORT, map) &&
 332             !test_bit(SCTP_CID_SHUTDOWN_ACK, map) &&
 333             !test_bit(SCTP_CID_HEARTBEAT, map) &&
 334             !test_bit(SCTP_CID_HEARTBEAT_ACK, map) &&
 335             sh->vtag != ct->proto.sctp.vtag[dir]) {
 336                 pr_debug("Verification tag check failed\n");
 337                 goto out;
 338         }
 339
 340         old_state = new_state = SCTP_CONNTRACK_NONE;
 341         spin_lock_bh(&ct->lock);
 342         for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
 343                 /* Special cases of Verification tag check (Sec 8.5.1) */
 344                 if (sch->type == SCTP_CID_INIT) {
 345                         /* Sec 8.5.1 (A) */
 346                         if (sh->vtag != 0)
 347                                 goto out_unlock;
 348                 } else if (sch->type == SCTP_CID_ABORT) {
 349                         /* Sec 8.5.1 (B) */
 350                         if (sh->vtag != ct->proto.sctp.vtag[dir] &&
 351                             sh->vtag != ct->proto.sctp.vtag[!dir])
 352                                 goto out_unlock;
 353                 } else if (sch->type == SCTP_CID_SHUTDOWN_COMPLETE) {
 354                         /* Sec 8.5.1 (C) */
 355                         if (sh->vtag != ct->proto.sctp.vtag[dir] &&
 356                             sh->vtag != ct->proto.sctp.vtag[!dir] &&
 357                             sch->flags & SCTP_CHUNK_FLAG_T)
 358                                 goto out_unlock;
 359                 } else if (sch->type == SCTP_CID_COOKIE_ECHO) {
 360                         /* Sec 8.5.1 (D) */
 361                         if (sh->vtag != ct->proto.sctp.vtag[dir])
 362                                 goto out_unlock;
 363                 } else if (sch->type == SCTP_CID_HEARTBEAT ||
 364                            sch->type == SCTP_CID_HEARTBEAT_ACK) {
 365                         if (ct->proto.sctp.vtag[dir] == 0) {
 366                                 pr_debug("Setting vtag %x for dir %d\n",
 367                                          sh->vtag, dir);
 368                                 ct->proto.sctp.vtag[dir] = sh->vtag;
 369                         } else if (sh->vtag != ct->proto.sctp.vtag[dir]) {
 370                                 pr_debug("Verification tag check failed\n");
 371                                 goto out_unlock;
 372                         }
 373                 }
 374
 375                 old_state = ct->proto.sctp.state;
 376                 new_state = sctp_new_state(dir, old_state, sch->type);
 377
 378                 /* Invalid */
 379                 if (new_state == SCTP_CONNTRACK_MAX) {
 380                         pr_debug("nf_conntrack_sctp: Invalid dir=%i ctype=%u "
 381                                  "conntrack=%u\n",
 382                                  dir, sch->type, old_state);
 383                         goto out_unlock;
 384                 }
 385
 386                 /* If it is an INIT or an INIT ACK note down the vtag */
 387                 if (sch->type == SCTP_CID_INIT ||
 388                     sch->type == SCTP_CID_INIT_ACK) {
 389                         struct sctp_inithdr _inithdr, *ih;
 390
 391                         ih = skb_header_pointer(skb, offset + sizeof(_sch),
 392                                                 sizeof(_inithdr), &_inithdr);
 393                         if (ih == NULL)
 394                                 goto out_unlock;
 395                         pr_debug("Setting vtag %x for dir %d\n",
 396                                  ih->init_tag, !dir);
 397                         ct->proto.sctp.vtag[!dir] = ih->init_tag;
 398                 }
 399
 400                 ct->proto.sctp.state = new_state;
 401                 if (old_state != new_state)
 402                         nf_conntrack_event_cache(IPCT_PROTOINFO, ct);
 403         }
 404         spin_unlock_bh(&ct->lock);
 405
 406         nf_ct_refresh_acct(ct, ctinfo, skb, timeouts[new_state]);
 407
 408         if (old_state == SCTP_CONNTRACK_COOKIE_ECHOED &&
 409             dir == IP_CT_DIR_REPLY &&
 410             new_state == SCTP_CONNTRACK_ESTABLISHED) {
 411                 pr_debug("Setting assured bit\n");
 412                 set_bit(IPS_ASSURED_BIT, &ct->status);
 413                 nf_conntrack_event_cache(IPCT_ASSURED, ct);
 414         }
 415
 416         return NF_ACCEPT;
 417
 418 out_unlock:
 419         spin_unlock_bh(&ct->lock);
 420 out:
 421         return -NF_ACCEPT;
 422 }
 423
 424 /* Called when a new connection for this protocol found. */
 425 static bool sctp_new(struct nf_conn *ct, const struct sk_buff *skb,
 426                      unsigned int dataoff, unsigned int *timeouts)
 427 {
 428         enum sctp_conntrack new_state;
 429         const struct sctphdr *sh;
 430         struct sctphdr _sctph;
 431         const struct sctp_chunkhdr *sch;
 432         struct sctp_chunkhdr _sch;
 433         u_int32_t offset, count;
 434         unsigned long map[256 / sizeof(unsigned long)] = { 0 };
 435
 436         sh = skb_header_pointer(skb, dataoff, sizeof(_sctph), &_sctph);
 437         if (sh == NULL)
 438                 return false;
 439
 440         if (do_basic_checks(ct, skb, dataoff, map) != 0)
 441                 return false;
 442
 443         /* If an OOTB packet has any of these chunks discard (Sec 8.4) */
 444         if (test_bit(SCTP_CID_ABORT, map) ||
 445             test_bit(SCTP_CID_SHUTDOWN_COMPLETE, map) ||
 446             test_bit(SCTP_CID_COOKIE_ACK, map))
 447                 return false;
 448
 449         memset(&ct->proto.sctp, 0, sizeof(ct->proto.sctp));
 450         new_state = SCTP_CONNTRACK_MAX;
 451         for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
 452                 /* Don't need lock here: this conntrack not in circulation yet */
 453                 new_state = sctp_new_state(IP_CT_DIR_ORIGINAL,
 454                                            SCTP_CONNTRACK_NONE, sch->type);
 455
 456                 /* Invalid: delete conntrack */
 457                 if (new_state == SCTP_CONNTRACK_NONE ||
 458                     new_state == SCTP_CONNTRACK_MAX) {
 459                         pr_debug("nf_conntrack_sctp: invalid new deleting.\n");
 460                         return false;
 461                 }
 462
 463                 /* Copy the vtag into the state info */
 464                 if (sch->type == SCTP_CID_INIT) {
 465                         struct sctp_inithdr _inithdr, *ih;
 466                         /* Sec 8.5.1 (A) */
 467                         if (sh->vtag)
 468                                 return false;
 469
 470                         ih = skb_header_pointer(skb, offset + sizeof(_sch),
 471                                                 sizeof(_inithdr), &_inithdr);
 472                         if (!ih)
 473                                 return false;
 474
 475                         pr_debug("Setting vtag %x for new conn\n",
 476                                  ih->init_tag);
 477
 478                         ct->proto.sctp.vtag[IP_CT_DIR_REPLY] = ih->init_tag;
 479                 } else if (sch->type == SCTP_CID_HEARTBEAT) {
 480                         pr_debug("Setting vtag %x for secondary conntrack\n",
 481                                  sh->vtag);
 482                         ct->proto.sctp.vtag[IP_CT_DIR_ORIGINAL] = sh->vtag;
 483                 }
 484                 /* If it is a shutdown ack OOTB packet, we expect a return
 485                    shutdown complete, otherwise an ABORT Sec 8.4 (5) and (8) */
 486                 else {
 487                         pr_debug("Setting vtag %x for new conn OOTB\n",
 488                                  sh->vtag);
 489                         ct->proto.sctp.vtag[IP_CT_DIR_REPLY] = sh->vtag;
 490                 }
 491
 492                 ct->proto.sctp.state = new_state;
 493         }
 494
 495         return true;
 496 }
 497
 498 static int sctp_error(struct net *net, struct nf_conn *tpl, struct sk_buff *skb,
 499                       unsigned int dataoff,
 500                       u8 pf, unsigned int hooknum)
 501 {
 502         const struct sctphdr *sh;
 503         const char *logmsg;
 504
 505         if (skb->len < dataoff + sizeof(struct sctphdr)) {
 506                 logmsg = "nf_ct_sctp: short packet ";
 507                 goto out_invalid;
 508         }
 509         if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
 510             skb->ip_summed == CHECKSUM_NONE) {
 511                 if (!skb_make_writable(skb, dataoff + sizeof(struct sctphdr))) {
 512                         logmsg = "nf_ct_sctp: failed to read header ";
 513                         goto out_invalid;
 514                 }
 515                 sh = (const struct sctphdr *)(skb->data + dataoff);
 516                 if (sh->checksum != sctp_compute_cksum(skb, dataoff)) {
 517                         logmsg = "nf_ct_sctp: bad CRC ";
 518                         goto out_invalid;
 519                 }
 520                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 521         }
 522         return NF_ACCEPT;
 523 out_invalid:
 524         nf_l4proto_log_invalid(skb, net, pf, IPPROTO_SCTP, "%s", logmsg);
 525         return -NF_ACCEPT;
 526 }
 527
 528 static bool sctp_can_early_drop(const struct nf_conn *ct)
 529 {
 530         switch (ct->proto.sctp.state) {
 531         case SCTP_CONNTRACK_SHUTDOWN_SENT:
 532         case SCTP_CONNTRACK_SHUTDOWN_RECD:
 533         case SCTP_CONNTRACK_SHUTDOWN_ACK_SENT:
 534                 return true;
 535         default:
 536                 break;
 537         }
 538
 539         return false;
 540 }
 541
 542 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 543
 544 #include <linux/netfilter/nfnetlink.h>
 545 #include <linux/netfilter/nfnetlink_conntrack.h>
 546
 547 static int sctp_to_nlattr(struct sk_buff *skb, struct nlattr *nla,
 548                           struct nf_conn *ct)
 549 {
 550         struct nlattr *nest_parms;
 551
 552         spin_lock_bh(&ct->lock);
 553         nest_parms = nla_nest_start(skb, CTA_PROTOINFO_SCTP | NLA_F_NESTED);
 554         if (!nest_parms)
 555                 goto nla_put_failure;
 556
 557         if (nla_put_u8(skb, CTA_PROTOINFO_SCTP_STATE, ct->proto.sctp.state) ||
 558             nla_put_be32(skb, CTA_PROTOINFO_SCTP_VTAG_ORIGINAL,
 559                          ct->proto.sctp.vtag[IP_CT_DIR_ORIGINAL]) ||
 560             nla_put_be32(skb, CTA_PROTOINFO_SCTP_VTAG_REPLY,
 561                          ct->proto.sctp.vtag[IP_CT_DIR_REPLY]))
 562                 goto nla_put_failure;
 563
 564         spin_unlock_bh(&ct->lock);
 565
 566         nla_nest_end(skb, nest_parms);
 567
 568         return 0;
 569
 570 nla_put_failure:
 571         spin_unlock_bh(&ct->lock);
 572         return -1;
 573 }
 574
 575 static const struct nla_policy sctp_nla_policy[CTA_PROTOINFO_SCTP_MAX+1] = {
 576         [CTA_PROTOINFO_SCTP_STATE]          = { .type = NLA_U8 },
 577         [CTA_PROTOINFO_SCTP_VTAG_ORIGINAL]  = { .type = NLA_U32 },
 578         [CTA_PROTOINFO_SCTP_VTAG_REPLY]     = { .type = NLA_U32 },
 579 };
 580
 581 #define SCTP_NLATTR_SIZE ( \
 582                 NLA_ALIGN(NLA_HDRLEN + 1) + \
 583                 NLA_ALIGN(NLA_HDRLEN + 4) + \
 584                 NLA_ALIGN(NLA_HDRLEN + 4))
 585
 586 static int nlattr_to_sctp(struct nlattr *cda[], struct nf_conn *ct)
 587 {
 588         struct nlattr *attr = cda[CTA_PROTOINFO_SCTP];
 589         struct nlattr *tb[CTA_PROTOINFO_SCTP_MAX+1];
 590         int err;
 591
 592         /* updates may not contain the internal protocol info, skip parsing */
 593         if (!attr)
 594                 return 0;
 595
 596         err = nla_parse_nested(tb, CTA_PROTOINFO_SCTP_MAX, attr,
 597                                sctp_nla_policy, NULL);
 598         if (err < 0)
 599                 return err;
 600
 601         if (!tb[CTA_PROTOINFO_SCTP_STATE] ||
 602             !tb[CTA_PROTOINFO_SCTP_VTAG_ORIGINAL] ||
 603             !tb[CTA_PROTOINFO_SCTP_VTAG_REPLY])
 604                 return -EINVAL;
 605
 606         spin_lock_bh(&ct->lock);
 607         ct->proto.sctp.state = nla_get_u8(tb[CTA_PROTOINFO_SCTP_STATE]);
 608         ct->proto.sctp.vtag[IP_CT_DIR_ORIGINAL] =
 609                 nla_get_be32(tb[CTA_PROTOINFO_SCTP_VTAG_ORIGINAL]);
 610         ct->proto.sctp.vtag[IP_CT_DIR_REPLY] =
 611                 nla_get_be32(tb[CTA_PROTOINFO_SCTP_VTAG_REPLY]);
 612         spin_unlock_bh(&ct->lock);
 613
 614         return 0;
 615 }
 616 #endif
 617
 618 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
 619
 620 #include <linux/netfilter/nfnetlink.h>
 621 #include <linux/netfilter/nfnetlink_cttimeout.h>
 622
 623 static int sctp_timeout_nlattr_to_obj(struct nlattr *tb[],
 624                                       struct net *net, void *data)
 625 {
 626         unsigned int *timeouts = data;
 627         struct nf_sctp_net *sn = sctp_pernet(net);
 628         int i;
 629
 630         /* set default SCTP timeouts. */
 631         for (i=0; i<SCTP_CONNTRACK_MAX; i++)
 632                 timeouts[i] = sn->timeouts[i];
 633
 634         /* there's a 1:1 mapping between attributes and protocol states. */
 635         for (i=CTA_TIMEOUT_SCTP_UNSPEC+1; i<CTA_TIMEOUT_SCTP_MAX+1; i++) {
 636                 if (tb[i]) {
 637                         timeouts[i] = ntohl(nla_get_be32(tb[i])) * HZ;
 638                 }
 639         }
 640         return 0;
 641 }
 642
 643 static int
 644 sctp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
 645 {
 646         const unsigned int *timeouts = data;
 647         int i;
 648
 649         for (i=CTA_TIMEOUT_SCTP_UNSPEC+1; i<CTA_TIMEOUT_SCTP_MAX+1; i++) {
 650                 if (nla_put_be32(skb, i, htonl(timeouts[i] / HZ)))
 651                         goto nla_put_failure;
 652         }
 653         return 0;
 654
 655 nla_put_failure:
 656         return -ENOSPC;
 657 }
 658
 659 static const struct nla_policy
 660 sctp_timeout_nla_policy[CTA_TIMEOUT_SCTP_MAX+1] = {
 661         [CTA_TIMEOUT_SCTP_CLOSED]               = { .type = NLA_U32 },
 662         [CTA_TIMEOUT_SCTP_COOKIE_WAIT]          = { .type = NLA_U32 },
 663         [CTA_TIMEOUT_SCTP_COOKIE_ECHOED]        = { .type = NLA_U32 },
 664         [CTA_TIMEOUT_SCTP_ESTABLISHED]          = { .type = NLA_U32 },
 665         [CTA_TIMEOUT_SCTP_SHUTDOWN_SENT]        = { .type = NLA_U32 },
 666         [CTA_TIMEOUT_SCTP_SHUTDOWN_RECD]        = { .type = NLA_U32 },
 667         [CTA_TIMEOUT_SCTP_SHUTDOWN_ACK_SENT]    = { .type = NLA_U32 },
 668         [CTA_TIMEOUT_SCTP_HEARTBEAT_SENT]       = { .type = NLA_U32 },
 669         [CTA_TIMEOUT_SCTP_HEARTBEAT_ACKED]      = { .type = NLA_U32 },
 670 };
 671 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 672
 673
 674 #ifdef CONFIG_SYSCTL
 675 static struct ctl_table sctp_sysctl_table[] = {
 676         {
 677                 .procname       = "nf_conntrack_sctp_timeout_closed",
 678                 .maxlen         = sizeof(unsigned int),
 679                 .mode           = 0644,
 680                 .proc_handler   = proc_dointvec_jiffies,
 681         },
 682         {
 683                 .procname       = "nf_conntrack_sctp_timeout_cookie_wait",
 684                 .maxlen         = sizeof(unsigned int),
 685                 .mode           = 0644,
 686                 .proc_handler   = proc_dointvec_jiffies,
 687         },
 688         {
 689                 .procname       = "nf_conntrack_sctp_timeout_cookie_echoed",
 690                 .maxlen         = sizeof(unsigned int),
 691                 .mode           = 0644,
 692                 .proc_handler   = proc_dointvec_jiffies,
 693         },
 694         {
 695                 .procname       = "nf_conntrack_sctp_timeout_established",
 696                 .maxlen         = sizeof(unsigned int),
 697                 .mode           = 0644,
 698                 .proc_handler   = proc_dointvec_jiffies,
 699         },
 700         {
 701                 .procname       = "nf_conntrack_sctp_timeout_shutdown_sent",
 702                 .maxlen         = sizeof(unsigned int),
 703                 .mode           = 0644,
 704                 .proc_handler   = proc_dointvec_jiffies,
 705         },
 706         {
 707                 .procname       = "nf_conntrack_sctp_timeout_shutdown_recd",
 708                 .maxlen         = sizeof(unsigned int),
 709                 .mode           = 0644,
 710                 .proc_handler   = proc_dointvec_jiffies,
 711         },
 712         {
 713                 .procname       = "nf_conntrack_sctp_timeout_shutdown_ack_sent",
 714                 .maxlen         = sizeof(unsigned int),
 715                 .mode           = 0644,
 716                 .proc_handler   = proc_dointvec_jiffies,
 717         },
 718         {
 719                 .procname       = "nf_conntrack_sctp_timeout_heartbeat_sent",
 720                 .maxlen         = sizeof(unsigned int),
 721                 .mode           = 0644,
 722                 .proc_handler   = proc_dointvec_jiffies,
 723         },
 724         {
 725                 .procname       = "nf_conntrack_sctp_timeout_heartbeat_acked",
 726                 .maxlen         = sizeof(unsigned int),
 727                 .mode           = 0644,
 728                 .proc_handler   = proc_dointvec_jiffies,
 729         },
 730         { }
 731 };
 732 #endif
 733
 734 static int sctp_kmemdup_sysctl_table(struct nf_proto_net *pn,
 735                                      struct nf_sctp_net *sn)
 736 {
 737 #ifdef CONFIG_SYSCTL
 738         if (pn->ctl_table)
 739                 return 0;
 740
 741         pn->ctl_table = kmemdup(sctp_sysctl_table,
 742                                 sizeof(sctp_sysctl_table),
 743                                 GFP_KERNEL);
 744         if (!pn->ctl_table)
 745                 return -ENOMEM;
 746
 747         pn->ctl_table[0].data = &sn->timeouts[SCTP_CONNTRACK_CLOSED];
 748         pn->ctl_table[1].data = &sn->timeouts[SCTP_CONNTRACK_COOKIE_WAIT];
 749         pn->ctl_table[2].data = &sn->timeouts[SCTP_CONNTRACK_COOKIE_ECHOED];
 750         pn->ctl_table[3].data = &sn->timeouts[SCTP_CONNTRACK_ESTABLISHED];
 751         pn->ctl_table[4].data = &sn->timeouts[SCTP_CONNTRACK_SHUTDOWN_SENT];
 752         pn->ctl_table[5].data = &sn->timeouts[SCTP_CONNTRACK_SHUTDOWN_RECD];
 753         pn->ctl_table[6].data = &sn->timeouts[SCTP_CONNTRACK_SHUTDOWN_ACK_SENT];
 754         pn->ctl_table[7].data = &sn->timeouts[SCTP_CONNTRACK_HEARTBEAT_SENT];
 755         pn->ctl_table[8].data = &sn->timeouts[SCTP_CONNTRACK_HEARTBEAT_ACKED];
 756 #endif
 757         return 0;
 758 }
 759
 760 static int sctp_init_net(struct net *net, u_int16_t proto)
 761 {
 762         struct nf_sctp_net *sn = sctp_pernet(net);
 763         struct nf_proto_net *pn = &sn->pn;
 764
 765         if (!pn->users) {
 766                 int i;
 767
 768                 for (i = 0; i < SCTP_CONNTRACK_MAX; i++)
 769                         sn->timeouts[i] = sctp_timeouts[i];
 770         }
 771
 772         return sctp_kmemdup_sysctl_table(pn, sn);
 773 }
 774
 775 static struct nf_proto_net *sctp_get_net_proto(struct net *net)
 776 {
 777         return &net->ct.nf_ct_proto.sctp.pn;
 778 }
 779
 780 const struct nf_conntrack_l4proto nf_conntrack_l4proto_sctp4 = {
 781         .l3proto                = PF_INET,
 782         .l4proto                = IPPROTO_SCTP,
 783         .pkt_to_tuple           = sctp_pkt_to_tuple,
 784         .invert_tuple           = sctp_invert_tuple,
 785 #ifdef CONFIG_NF_CONNTRACK_PROCFS
 786         .print_conntrack        = sctp_print_conntrack,
 787 #endif
 788         .packet                 = sctp_packet,
 789         .get_timeouts           = sctp_get_timeouts,
 790         .new                    = sctp_new,
 791         .error                  = sctp_error,
 792         .can_early_drop         = sctp_can_early_drop,
 793         .me                     = THIS_MODULE,
 794 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 795         .nlattr_size            = SCTP_NLATTR_SIZE,
 796         .to_nlattr              = sctp_to_nlattr,
 797         .from_nlattr            = nlattr_to_sctp,
 798         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
 799         .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
 800         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
 801         .nla_policy             = nf_ct_port_nla_policy,
 802 #endif
 803 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
 804         .ctnl_timeout           = {
 805                 .nlattr_to_obj  = sctp_timeout_nlattr_to_obj,
 806                 .obj_to_nlattr  = sctp_timeout_obj_to_nlattr,
 807                 .nlattr_max     = CTA_TIMEOUT_SCTP_MAX,
 808                 .obj_size       = sizeof(unsigned int) * SCTP_CONNTRACK_MAX,
 809                 .nla_policy     = sctp_timeout_nla_policy,
 810         },
 811 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 812         .init_net               = sctp_init_net,
 813         .get_net_proto          = sctp_get_net_proto,
 814 };
 815 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_sctp4);
 816
 817 const struct nf_conntrack_l4proto nf_conntrack_l4proto_sctp6 = {
 818         .l3proto                = PF_INET6,
 819         .l4proto                = IPPROTO_SCTP,
 820         .pkt_to_tuple           = sctp_pkt_to_tuple,
 821         .invert_tuple           = sctp_invert_tuple,
 822 #ifdef CONFIG_NF_CONNTRACK_PROCFS
 823         .print_conntrack        = sctp_print_conntrack,
 824 #endif
 825         .packet                 = sctp_packet,
 826         .get_timeouts           = sctp_get_timeouts,
 827         .new                    = sctp_new,
 828         .error                  = sctp_error,
 829         .can_early_drop         = sctp_can_early_drop,
 830         .me                     = THIS_MODULE,
 831 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 832         .nlattr_size            = SCTP_NLATTR_SIZE,
 833         .to_nlattr              = sctp_to_nlattr,
 834         .from_nlattr            = nlattr_to_sctp,
 835         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
 836         .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
 837         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
 838         .nla_policy             = nf_ct_port_nla_policy,
 839 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
 840         .ctnl_timeout           = {
 841                 .nlattr_to_obj  = sctp_timeout_nlattr_to_obj,
 842                 .obj_to_nlattr  = sctp_timeout_obj_to_nlattr,
 843                 .nlattr_max     = CTA_TIMEOUT_SCTP_MAX,
 844                 .obj_size       = sizeof(unsigned int) * SCTP_CONNTRACK_MAX,
 845                 .nla_policy     = sctp_timeout_nla_policy,
 846         },
 847 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 848 #endif
 849         .init_net               = sctp_init_net,
 850         .get_net_proto          = sctp_get_net_proto,
 851 };
 852 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_sctp6);