linux/net/netfilter/nf_conntrack_proto_sctp.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Connection tracking protocol helper module for SCTP.
   4 *
   5 * Copyright (c) 2004 Kiran Kumar Immidi <immidi_kiran@yahoo.com>
   6 * Copyright (c) 2004-2012 Patrick McHardy <kaber@trash.net>
   7 *
   8 * SCTP is defined in RFC 2960. References to various sections in this code
   9 * are to this RFC.
  10 */
  11
  12#include <linux/types.h>
  13#include <linux/timer.h>
  14#include <linux/netfilter.h>
  15#include <linux/in.h>
  16#include <linux/ip.h>
  17#include <linux/sctp.h>
  18#include <linux/string.h>
  19#include <linux/seq_file.h>
  20#include <linux/spinlock.h>
  21#include <linux/interrupt.h>
  22#include <net/sctp/checksum.h>
  23
  24#include <net/netfilter/nf_log.h>
  25#include <net/netfilter/nf_conntrack.h>
  26#include <net/netfilter/nf_conntrack_l4proto.h>
  27#include <net/netfilter/nf_conntrack_ecache.h>
  28#include <net/netfilter/nf_conntrack_timeout.h>
  29
  30/* FIXME: Examine ipfilter's timeouts and conntrack transitions more
  31   closely.  They're more complex. --RR
  32
  33   And so for me for SCTP :D -Kiran */
  34
  35static const char *const sctp_conntrack_names[] = {
  36        "NONE",
  37        "CLOSED",
  38        "COOKIE_WAIT",
  39        "COOKIE_ECHOED",
  40        "ESTABLISHED",
  41        "SHUTDOWN_SENT",
  42        "SHUTDOWN_RECD",
  43        "SHUTDOWN_ACK_SENT",
  44        "HEARTBEAT_SENT",
  45        "HEARTBEAT_ACKED",
  46};
  47
  48#define SECS  * HZ
  49#define MINS  * 60 SECS
  50#define HOURS * 60 MINS
  51#define DAYS  * 24 HOURS
  52
  53static const unsigned int sctp_timeouts[SCTP_CONNTRACK_MAX] = {
  54        [SCTP_CONNTRACK_CLOSED]                 = 10 SECS,
  55        [SCTP_CONNTRACK_COOKIE_WAIT]            = 3 SECS,
  56        [SCTP_CONNTRACK_COOKIE_ECHOED]          = 3 SECS,
  57        [SCTP_CONNTRACK_ESTABLISHED]            = 5 DAYS,
  58        [SCTP_CONNTRACK_SHUTDOWN_SENT]          = 300 SECS / 1000,
  59        [SCTP_CONNTRACK_SHUTDOWN_RECD]          = 300 SECS / 1000,
  60        [SCTP_CONNTRACK_SHUTDOWN_ACK_SENT]      = 3 SECS,
  61        [SCTP_CONNTRACK_HEARTBEAT_SENT]         = 30 SECS,
  62        [SCTP_CONNTRACK_HEARTBEAT_ACKED]        = 210 SECS,
  63};
  64
  65#define SCTP_FLAG_HEARTBEAT_VTAG_FAILED 1
  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
  82NOTE: These state names are tantalizingly similar to the states of an
  83SCTP endpoint. But the interpretation of the states is a little different,
  84considering that these are the states of the connection and not of an end
  85point. Please note the subtleties. -Kiran
  86
  87NONE              - Nothing so far.
  88COOKIE WAIT       - We have seen an INIT chunk in the original direction, or also
  89                    an INIT_ACK chunk in the reply direction.
  90COOKIE ECHOED     - We have seen a COOKIE_ECHO chunk in the original direction.
  91ESTABLISHED       - We have seen a COOKIE_ACK in the reply direction.
  92SHUTDOWN_SENT     - We have seen a SHUTDOWN chunk in the original direction.
  93SHUTDOWN_RECD     - We have seen a SHUTDOWN chunk in the reply directoin.
  94SHUTDOWN_ACK_SENT - We have seen a SHUTDOWN_ACK chunk in the direction opposite
  95                    to that of the SHUTDOWN chunk.
  96CLOSED            - We have seen a SHUTDOWN_COMPLETE chunk in the direction of
  97                    the SHUTDOWN chunk. Connection is closed.
  98HEARTBEAT_SENT    - We have seen a HEARTBEAT in a new flow.
  99HEARTBEAT_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
 109cookie echoed to closed.
 110 - Sec 5.2.4 of RFC 2960
 111 - Full Multi Homing support.
 112*/
 113
 114/* SCTP conntrack state transitions */
 115static 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         */ {sCL, sCL, 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, sCW, 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#ifdef CONFIG_NF_CONNTRACK_PROCFS
 149/* Print out the private part of the conntrack. */
 150static void sctp_print_conntrack(struct seq_file *s, struct nf_conn *ct)
 151{
 152        seq_printf(s, "%s ", sctp_conntrack_names[ct->proto.sctp.state]);
 153}
 154#endif
 155
 156#define for_each_sctp_chunk(skb, sch, _sch, offset, dataoff, count)     \
 157for ((offset) = (dataoff) + sizeof(struct sctphdr), (count) = 0;        \
 158        (offset) < (skb)->len &&                                        \
 159        ((sch) = skb_header_pointer((skb), (offset), sizeof(_sch), &(_sch)));   \
 160        (offset) += (ntohs((sch)->length) + 3) & ~3, (count)++)
 161
 162/* Some validity checks to make sure the chunks are fine */
 163static int do_basic_checks(struct nf_conn *ct,
 164                           const struct sk_buff *skb,
 165                           unsigned int dataoff,
 166                           unsigned long *map)
 167{
 168        u_int32_t offset, count;
 169        struct sctp_chunkhdr _sch, *sch;
 170        int flag;
 171
 172        flag = 0;
 173
 174        for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
 175                pr_debug("Chunk Num: %d  Type: %d\n", count, sch->type);
 176
 177                if (sch->type == SCTP_CID_INIT ||
 178                    sch->type == SCTP_CID_INIT_ACK ||
 179                    sch->type == SCTP_CID_SHUTDOWN_COMPLETE)
 180                        flag = 1;
 181
 182                /*
 183                 * Cookie Ack/Echo chunks not the first OR
 184                 * Init / Init Ack / Shutdown compl chunks not the only chunks
 185                 * OR zero-length.
 186                 */
 187                if (((sch->type == SCTP_CID_COOKIE_ACK ||
 188                      sch->type == SCTP_CID_COOKIE_ECHO ||
 189                      flag) &&
 190                     count != 0) || !sch->length) {
 191                        pr_debug("Basic checks failed\n");
 192                        return 1;
 193                }
 194
 195                if (map)
 196                        set_bit(sch->type, map);
 197        }
 198
 199        pr_debug("Basic checks passed\n");
 200        return count == 0;
 201}
 202
 203static int sctp_new_state(enum ip_conntrack_dir dir,
 204                          enum sctp_conntrack cur_state,
 205                          int chunk_type)
 206{
 207        int i;
 208
 209        pr_debug("Chunk type: %d\n", chunk_type);
 210
 211        switch (chunk_type) {
 212        case SCTP_CID_INIT:
 213                pr_debug("SCTP_CID_INIT\n");
 214                i = 0;
 215                break;
 216        case SCTP_CID_INIT_ACK:
 217                pr_debug("SCTP_CID_INIT_ACK\n");
 218                i = 1;
 219                break;
 220        case SCTP_CID_ABORT:
 221                pr_debug("SCTP_CID_ABORT\n");
 222                i = 2;
 223                break;
 224        case SCTP_CID_SHUTDOWN:
 225                pr_debug("SCTP_CID_SHUTDOWN\n");
 226                i = 3;
 227                break;
 228        case SCTP_CID_SHUTDOWN_ACK:
 229                pr_debug("SCTP_CID_SHUTDOWN_ACK\n");
 230                i = 4;
 231                break;
 232        case SCTP_CID_ERROR:
 233                pr_debug("SCTP_CID_ERROR\n");
 234                i = 5;
 235                break;
 236        case SCTP_CID_COOKIE_ECHO:
 237                pr_debug("SCTP_CID_COOKIE_ECHO\n");
 238                i = 6;
 239                break;
 240        case SCTP_CID_COOKIE_ACK:
 241                pr_debug("SCTP_CID_COOKIE_ACK\n");
 242                i = 7;
 243                break;
 244        case SCTP_CID_SHUTDOWN_COMPLETE:
 245                pr_debug("SCTP_CID_SHUTDOWN_COMPLETE\n");
 246                i = 8;
 247                break;
 248        case SCTP_CID_HEARTBEAT:
 249                pr_debug("SCTP_CID_HEARTBEAT");
 250                i = 9;
 251                break;
 252        case SCTP_CID_HEARTBEAT_ACK:
 253                pr_debug("SCTP_CID_HEARTBEAT_ACK");
 254                i = 10;
 255                break;
 256        default:
 257                /* Other chunks like DATA or SACK do not change the state */
 258                pr_debug("Unknown chunk type, Will stay in %s\n",
 259                         sctp_conntrack_names[cur_state]);
 260                return cur_state;
 261        }
 262
 263        pr_debug("dir: %d   cur_state: %s  chunk_type: %d  new_state: %s\n",
 264                 dir, sctp_conntrack_names[cur_state], chunk_type,
 265                 sctp_conntrack_names[sctp_conntracks[dir][i][cur_state]]);
 266
 267        return sctp_conntracks[dir][i][cur_state];
 268}
 269
 270/* Don't need lock here: this conntrack not in circulation yet */
 271static noinline bool
 272sctp_new(struct nf_conn *ct, const struct sk_buff *skb,
 273         const struct sctphdr *sh, unsigned int dataoff)
 274{
 275        enum sctp_conntrack new_state;
 276        const struct sctp_chunkhdr *sch;
 277        struct sctp_chunkhdr _sch;
 278        u32 offset, count;
 279
 280        memset(&ct->proto.sctp, 0, sizeof(ct->proto.sctp));
 281        new_state = SCTP_CONNTRACK_MAX;
 282        for_each_sctp_chunk(skb, sch, _sch, offset, dataoff, count) {
 283                new_state = sctp_new_state(IP_CT_DIR_ORIGINAL,
 284                                           SCTP_CONNTRACK_NONE, sch->type);
 285
 286                /* Invalid: delete conntrack */
 287                if (new_state == SCTP_CONNTRACK_NONE ||
 288                    new_state == SCTP_CONNTRACK_MAX) {
 289                        pr_debug("nf_conntrack_sctp: invalid new deleting.\n");
 290                        return false;
 291                }
 292
 293                /* Copy the vtag into the state info */
 294                if (sch->type == SCTP_CID_INIT) {
 295                        struct sctp_inithdr _inithdr, *ih;
 296                        /* Sec 8.5.1 (A) */
 297                        if (sh->vtag)
 298                                return false;
 299
 300                        ih = skb_header_pointer(skb, offset + sizeof(_sch),
 301                                                sizeof(_inithdr), &_inithdr);
 302                        if (!ih)
 303                                return false;
 304
 305                        pr_debug("Setting vtag %x for new conn\n",
 306                                 ih->init_tag);
 307
 308                        ct->proto.sctp.vtag[IP_CT_DIR_REPLY] = ih->init_tag;
 309                } else if (sch->type == SCTP_CID_HEARTBEAT) {
 310                        pr_debug("Setting vtag %x for secondary conntrack\n",
 311                                 sh->vtag);
 312                        ct->proto.sctp.vtag[IP_CT_DIR_ORIGINAL] = sh->vtag;
 313                } else {
 314                /* If it is a shutdown ack OOTB packet, we expect a return
 315                   shutdown complete, otherwise an ABORT Sec 8.4 (5) and (8) */
 316                        pr_debug("Setting vtag %x for new conn OOTB\n",
 317                                 sh->vtag);
 318                        ct->proto.sctp.vtag[IP_CT_DIR_REPLY] = sh->vtag;
 319                }
 320
 321                ct->proto.sctp.state = SCTP_CONNTRACK_NONE;
 322        }
 323
 324        return true;
 325}
 326
 327static bool sctp_error(struct sk_buff *skb,
 328                       unsigned int dataoff,
 329                       const struct nf_hook_state *state)
 330{
 331        const struct sctphdr *sh;
 332        const char *logmsg;
 333
 334        if (skb->len < dataoff + sizeof(struct sctphdr)) {
 335                logmsg = "nf_ct_sctp: short packet ";
 336                goto out_invalid;
 337        }
 338        if (state->hook == NF_INET_PRE_ROUTING &&
 339            state->net->ct.sysctl_checksum &&
 340            skb->ip_summed == CHECKSUM_NONE) {
 341                if (skb_ensure_writable(skb, dataoff + sizeof(*sh))) {
 342                        logmsg = "nf_ct_sctp: failed to read header ";
 343                        goto out_invalid;
 344                }
 345                sh = (const struct sctphdr *)(skb->data + dataoff);
 346                if (sh->checksum != sctp_compute_cksum(skb, dataoff)) {
 347                        logmsg = "nf_ct_sctp: bad CRC ";
 348                        goto out_invalid;
 349                }
 350                skb->ip_summed = CHECKSUM_UNNECESSARY;
 351        }
 352        return false;
 353out_invalid:
 354        nf_l4proto_log_invalid(skb, state->net, state->pf, IPPROTO_SCTP, "%s", logmsg);
 355        return true;
 356}
 357
 358/* Returns verdict for packet, or -NF_ACCEPT for invalid. */
 359int nf_conntrack_sctp_packet(struct nf_conn *ct,
 360                             struct sk_buff *skb,
 361                             unsigned int dataoff,
 362                             enum ip_conntrack_info ctinfo,
 363                             const struct nf_hook_state *state)
 364{
 365        enum sctp_conntrack new_state, old_state;
 366        enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
 367        const struct sctphdr *sh;
 368        struct sctphdr _sctph;
 369        const struct sctp_chunkhdr *sch;
 370        struct sctp_chunkhdr _sch;
 371        u_int32_t offset, count;
 372        unsigned int *timeouts;
 373        unsigned long map[256 / sizeof(unsigned long)] = { 0 };
 374        bool ignore = false;
 375
 376        if (sctp_error(skb, dataoff, state))
 377                return -NF_ACCEPT;
 378
 379        sh = skb_header_pointer(skb, dataoff, sizeof(_sctph), &_sctph);
 380        if (sh == NULL)
 381                goto out;
 382
 383        if (do_basic_checks(ct, skb, dataoff, map) != 0)
 384                goto out;
 385
 386        if (!nf_ct_is_confirmed(ct)) {
 387                /* If an OOTB packet has any of these chunks discard (Sec 8.4) */
 388                if (test_bit(SCTP_CID_ABORT, map) ||
 389                    test_bit(SCTP_CID_SHUTDOWN_COMPLETE, map) ||
 390                    test_bit(SCTP_CID_COOKIE_ACK, map))
 391                        return -NF_ACCEPT;
 392
 393                if (!sctp_new(ct, skb, sh, dataoff))
 394                        return -NF_ACCEPT;
 395        }
 396
 397        /* Check the verification tag (Sec 8.5) */
 398        if (!test_bit(SCTP_CID_INIT, map) &&
 399            !test_bit(SCTP_CID_SHUTDOWN_COMPLETE, map) &&
 400            !test_bit(SCTP_CID_COOKIE_ECHO, map) &&
 401            !test_bit(SCTP_CID_ABORT, map) &&
 402            !test_bit(SCTP_CID_SHUTDOWN_ACK, map) &&
 403            !test_bit(SCTP_CID_HEARTBEAT, map) &&
 404            !test_bit(SCTP_CID_HEARTBEAT_ACK, map) &&
 405            sh->vtag != ct->proto.sctp.vtag[dir]) {
 406                pr_debug("Verification tag check failed\n");
 407                goto out;
 408        }
 409
 410        old_state = new_state = SCTP_CONNTRACK_NONE;
 411        spin_lock_bh(&ct->lock);
 412        for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
 413                /* Special cases of Verification tag check (Sec 8.5.1) */
 414                if (sch->type == SCTP_CID_INIT) {
 415                        /* Sec 8.5.1 (A) */
 416                        if (sh->vtag != 0)
 417                                goto out_unlock;
 418                } else if (sch->type == SCTP_CID_ABORT) {
 419                        /* Sec 8.5.1 (B) */
 420                        if (sh->vtag != ct->proto.sctp.vtag[dir] &&
 421                            sh->vtag != ct->proto.sctp.vtag[!dir])
 422                                goto out_unlock;
 423                } else if (sch->type == SCTP_CID_SHUTDOWN_COMPLETE) {
 424                        /* Sec 8.5.1 (C) */
 425                        if (sh->vtag != ct->proto.sctp.vtag[dir] &&
 426                            sh->vtag != ct->proto.sctp.vtag[!dir] &&
 427                            sch->flags & SCTP_CHUNK_FLAG_T)
 428                                goto out_unlock;
 429                } else if (sch->type == SCTP_CID_COOKIE_ECHO) {
 430                        /* Sec 8.5.1 (D) */
 431                        if (sh->vtag != ct->proto.sctp.vtag[dir])
 432                                goto out_unlock;
 433                } else if (sch->type == SCTP_CID_HEARTBEAT) {
 434                        if (ct->proto.sctp.vtag[dir] == 0) {
 435                                pr_debug("Setting %d vtag %x for dir %d\n", sch->type, sh->vtag, dir);
 436                                ct->proto.sctp.vtag[dir] = sh->vtag;
 437                        } else if (sh->vtag != ct->proto.sctp.vtag[dir]) {
 438                                if (test_bit(SCTP_CID_DATA, map) || ignore)
 439                                        goto out_unlock;
 440
 441                                ct->proto.sctp.flags |= SCTP_FLAG_HEARTBEAT_VTAG_FAILED;
 442                                ct->proto.sctp.last_dir = dir;
 443                                ignore = true;
 444                                continue;
 445                        } else if (ct->proto.sctp.flags & SCTP_FLAG_HEARTBEAT_VTAG_FAILED) {
 446                                ct->proto.sctp.flags &= ~SCTP_FLAG_HEARTBEAT_VTAG_FAILED;
 447                        }
 448                } else if (sch->type == SCTP_CID_HEARTBEAT_ACK) {
 449                        if (ct->proto.sctp.vtag[dir] == 0) {
 450                                pr_debug("Setting vtag %x for dir %d\n",
 451                                         sh->vtag, dir);
 452                                ct->proto.sctp.vtag[dir] = sh->vtag;
 453                        } else if (sh->vtag != ct->proto.sctp.vtag[dir]) {
 454                                if (test_bit(SCTP_CID_DATA, map) || ignore)
 455                                        goto out_unlock;
 456
 457                                if ((ct->proto.sctp.flags & SCTP_FLAG_HEARTBEAT_VTAG_FAILED) == 0 ||
 458                                    ct->proto.sctp.last_dir == dir)
 459                                        goto out_unlock;
 460
 461                                ct->proto.sctp.flags &= ~SCTP_FLAG_HEARTBEAT_VTAG_FAILED;
 462                                ct->proto.sctp.vtag[dir] = sh->vtag;
 463                                ct->proto.sctp.vtag[!dir] = 0;
 464                        } else if (ct->proto.sctp.flags & SCTP_FLAG_HEARTBEAT_VTAG_FAILED) {
 465                                ct->proto.sctp.flags &= ~SCTP_FLAG_HEARTBEAT_VTAG_FAILED;
 466                        }
 467                }
 468
 469                old_state = ct->proto.sctp.state;
 470                new_state = sctp_new_state(dir, old_state, sch->type);
 471
 472                /* Invalid */
 473                if (new_state == SCTP_CONNTRACK_MAX) {
 474                        pr_debug("nf_conntrack_sctp: Invalid dir=%i ctype=%u "
 475                                 "conntrack=%u\n",
 476                                 dir, sch->type, old_state);
 477                        goto out_unlock;
 478                }
 479
 480                /* If it is an INIT or an INIT ACK note down the vtag */
 481                if (sch->type == SCTP_CID_INIT ||
 482                    sch->type == SCTP_CID_INIT_ACK) {
 483                        struct sctp_inithdr _inithdr, *ih;
 484
 485                        ih = skb_header_pointer(skb, offset + sizeof(_sch),
 486                                                sizeof(_inithdr), &_inithdr);
 487                        if (ih == NULL)
 488                                goto out_unlock;
 489                        pr_debug("Setting vtag %x for dir %d\n",
 490                                 ih->init_tag, !dir);
 491                        ct->proto.sctp.vtag[!dir] = ih->init_tag;
 492                }
 493
 494                ct->proto.sctp.state = new_state;
 495                if (old_state != new_state)
 496                        nf_conntrack_event_cache(IPCT_PROTOINFO, ct);
 497        }
 498        spin_unlock_bh(&ct->lock);
 499
 500        /* allow but do not refresh timeout */
 501        if (ignore)
 502                return NF_ACCEPT;
 503
 504        timeouts = nf_ct_timeout_lookup(ct);
 505        if (!timeouts)
 506                timeouts = nf_sctp_pernet(nf_ct_net(ct))->timeouts;
 507
 508        nf_ct_refresh_acct(ct, ctinfo, skb, timeouts[new_state]);
 509
 510        if (old_state == SCTP_CONNTRACK_COOKIE_ECHOED &&
 511            dir == IP_CT_DIR_REPLY &&
 512            new_state == SCTP_CONNTRACK_ESTABLISHED) {
 513                pr_debug("Setting assured bit\n");
 514                set_bit(IPS_ASSURED_BIT, &ct->status);
 515                nf_conntrack_event_cache(IPCT_ASSURED, ct);
 516        }
 517
 518        return NF_ACCEPT;
 519
 520out_unlock:
 521        spin_unlock_bh(&ct->lock);
 522out:
 523        return -NF_ACCEPT;
 524}
 525
 526static bool sctp_can_early_drop(const struct nf_conn *ct)
 527{
 528        switch (ct->proto.sctp.state) {
 529        case SCTP_CONNTRACK_SHUTDOWN_SENT:
 530        case SCTP_CONNTRACK_SHUTDOWN_RECD:
 531        case SCTP_CONNTRACK_SHUTDOWN_ACK_SENT:
 532                return true;
 533        default:
 534                break;
 535        }
 536
 537        return false;
 538}
 539
 540#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 541
 542#include <linux/netfilter/nfnetlink.h>
 543#include <linux/netfilter/nfnetlink_conntrack.h>
 544
 545static int sctp_to_nlattr(struct sk_buff *skb, struct nlattr *nla,
 546                          struct nf_conn *ct, bool destroy)
 547{
 548        struct nlattr *nest_parms;
 549
 550        spin_lock_bh(&ct->lock);
 551        nest_parms = nla_nest_start(skb, CTA_PROTOINFO_SCTP);
 552        if (!nest_parms)
 553                goto nla_put_failure;
 554
 555        if (nla_put_u8(skb, CTA_PROTOINFO_SCTP_STATE, ct->proto.sctp.state))
 556                goto nla_put_failure;
 557
 558        if (destroy)
 559                goto skip_state;
 560
 561        if (nla_put_be32(skb, CTA_PROTOINFO_SCTP_VTAG_ORIGINAL,
 562                         ct->proto.sctp.vtag[IP_CT_DIR_ORIGINAL]) ||
 563            nla_put_be32(skb, CTA_PROTOINFO_SCTP_VTAG_REPLY,
 564                         ct->proto.sctp.vtag[IP_CT_DIR_REPLY]))
 565                goto nla_put_failure;
 566
 567skip_state:
 568        spin_unlock_bh(&ct->lock);
 569        nla_nest_end(skb, nest_parms);
 570
 571        return 0;
 572
 573nla_put_failure:
 574        spin_unlock_bh(&ct->lock);
 575        return -1;
 576}
 577
 578static const struct nla_policy sctp_nla_policy[CTA_PROTOINFO_SCTP_MAX+1] = {
 579        [CTA_PROTOINFO_SCTP_STATE]          = { .type = NLA_U8 },
 580        [CTA_PROTOINFO_SCTP_VTAG_ORIGINAL]  = { .type = NLA_U32 },
 581        [CTA_PROTOINFO_SCTP_VTAG_REPLY]     = { .type = NLA_U32 },
 582};
 583
 584#define SCTP_NLATTR_SIZE ( \
 585                NLA_ALIGN(NLA_HDRLEN + 1) + \
 586                NLA_ALIGN(NLA_HDRLEN + 4) + \
 587                NLA_ALIGN(NLA_HDRLEN + 4))
 588
 589static int nlattr_to_sctp(struct nlattr *cda[], struct nf_conn *ct)
 590{
 591        struct nlattr *attr = cda[CTA_PROTOINFO_SCTP];
 592        struct nlattr *tb[CTA_PROTOINFO_SCTP_MAX+1];
 593        int err;
 594
 595        /* updates may not contain the internal protocol info, skip parsing */
 596        if (!attr)
 597                return 0;
 598
 599        err = nla_parse_nested_deprecated(tb, CTA_PROTOINFO_SCTP_MAX, attr,
 600                                          sctp_nla_policy, NULL);
 601        if (err < 0)
 602                return err;
 603
 604        if (!tb[CTA_PROTOINFO_SCTP_STATE] ||
 605            !tb[CTA_PROTOINFO_SCTP_VTAG_ORIGINAL] ||
 606            !tb[CTA_PROTOINFO_SCTP_VTAG_REPLY])
 607                return -EINVAL;
 608
 609        spin_lock_bh(&ct->lock);
 610        ct->proto.sctp.state = nla_get_u8(tb[CTA_PROTOINFO_SCTP_STATE]);
 611        ct->proto.sctp.vtag[IP_CT_DIR_ORIGINAL] =
 612                nla_get_be32(tb[CTA_PROTOINFO_SCTP_VTAG_ORIGINAL]);
 613        ct->proto.sctp.vtag[IP_CT_DIR_REPLY] =
 614                nla_get_be32(tb[CTA_PROTOINFO_SCTP_VTAG_REPLY]);
 615        spin_unlock_bh(&ct->lock);
 616
 617        return 0;
 618}
 619#endif
 620
 621#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
 622
 623#include <linux/netfilter/nfnetlink.h>
 624#include <linux/netfilter/nfnetlink_cttimeout.h>
 625
 626static int sctp_timeout_nlattr_to_obj(struct nlattr *tb[],
 627                                      struct net *net, void *data)
 628{
 629        unsigned int *timeouts = data;
 630        struct nf_sctp_net *sn = nf_sctp_pernet(net);
 631        int i;
 632
 633        if (!timeouts)
 634                timeouts = sn->timeouts;
 635
 636        /* set default SCTP timeouts. */
 637        for (i=0; i<SCTP_CONNTRACK_MAX; i++)
 638                timeouts[i] = sn->timeouts[i];
 639
 640        /* there's a 1:1 mapping between attributes and protocol states. */
 641        for (i=CTA_TIMEOUT_SCTP_UNSPEC+1; i<CTA_TIMEOUT_SCTP_MAX+1; i++) {
 642                if (tb[i]) {
 643                        timeouts[i] = ntohl(nla_get_be32(tb[i])) * HZ;
 644                }
 645        }
 646
 647        timeouts[CTA_TIMEOUT_SCTP_UNSPEC] = timeouts[CTA_TIMEOUT_SCTP_CLOSED];
 648        return 0;
 649}
 650
 651static int
 652sctp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
 653{
 654        const unsigned int *timeouts = data;
 655        int i;
 656
 657        for (i=CTA_TIMEOUT_SCTP_UNSPEC+1; i<CTA_TIMEOUT_SCTP_MAX+1; i++) {
 658                if (nla_put_be32(skb, i, htonl(timeouts[i] / HZ)))
 659                        goto nla_put_failure;
 660        }
 661        return 0;
 662
 663nla_put_failure:
 664        return -ENOSPC;
 665}
 666
 667static const struct nla_policy
 668sctp_timeout_nla_policy[CTA_TIMEOUT_SCTP_MAX+1] = {
 669        [CTA_TIMEOUT_SCTP_CLOSED]               = { .type = NLA_U32 },
 670        [CTA_TIMEOUT_SCTP_COOKIE_WAIT]          = { .type = NLA_U32 },
 671        [CTA_TIMEOUT_SCTP_COOKIE_ECHOED]        = { .type = NLA_U32 },
 672        [CTA_TIMEOUT_SCTP_ESTABLISHED]          = { .type = NLA_U32 },
 673        [CTA_TIMEOUT_SCTP_SHUTDOWN_SENT]        = { .type = NLA_U32 },
 674        [CTA_TIMEOUT_SCTP_SHUTDOWN_RECD]        = { .type = NLA_U32 },
 675        [CTA_TIMEOUT_SCTP_SHUTDOWN_ACK_SENT]    = { .type = NLA_U32 },
 676        [CTA_TIMEOUT_SCTP_HEARTBEAT_SENT]       = { .type = NLA_U32 },
 677        [CTA_TIMEOUT_SCTP_HEARTBEAT_ACKED]      = { .type = NLA_U32 },
 678};
 679#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
 680
 681void nf_conntrack_sctp_init_net(struct net *net)
 682{
 683        struct nf_sctp_net *sn = nf_sctp_pernet(net);
 684        int i;
 685
 686        for (i = 0; i < SCTP_CONNTRACK_MAX; i++)
 687                sn->timeouts[i] = sctp_timeouts[i];
 688
 689        /* timeouts[0] is unused, init it so ->timeouts[0] contains
 690         * 'new' timeout, like udp or icmp.
 691         */
 692        sn->timeouts[0] = sctp_timeouts[SCTP_CONNTRACK_CLOSED];
 693}
 694
 695const struct nf_conntrack_l4proto nf_conntrack_l4proto_sctp = {
 696        .l4proto                = IPPROTO_SCTP,
 697#ifdef CONFIG_NF_CONNTRACK_PROCFS
 698        .print_conntrack        = sctp_print_conntrack,
 699#endif
 700        .can_early_drop         = sctp_can_early_drop,
 701#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 702        .nlattr_size            = SCTP_NLATTR_SIZE,
 703        .to_nlattr              = sctp_to_nlattr,
 704        .from_nlattr            = nlattr_to_sctp,
 705        .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
 706        .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
 707        .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
 708        .nla_policy             = nf_ct_port_nla_policy,
 709#endif
 710#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
 711        .ctnl_timeout           = {
 712                .nlattr_to_obj  = sctp_timeout_nlattr_to_obj,
 713                .obj_to_nlattr  = sctp_timeout_obj_to_nlattr,
 714                .nlattr_max     = CTA_TIMEOUT_SCTP_MAX,
 715                .obj_size       = sizeof(unsigned int) * SCTP_CONNTRACK_MAX,
 716                .nla_policy     = sctp_timeout_nla_policy,
 717        },
 718#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
 719};
 720
The original LXR software by the LXR community, this experimental version by lxr@linux.no.