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   1 /* SIP extension for IP connection tracking.
   2  *
   3  * (C) 2005 by Christian Hentschel <chentschel@arnet.com.ar>
   4  * based on RR's ip_conntrack_ftp.c and other modules.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/ctype.h>
  13 #include <linux/skbuff.h>
  14 #include <linux/inet.h>
  15 #include <linux/in.h>
  16 #include <linux/udp.h>
  17 #include <linux/netfilter.h>
  18
  19 #include <net/netfilter/nf_conntrack.h>
  20 #include <net/netfilter/nf_conntrack_core.h>
  21 #include <net/netfilter/nf_conntrack_expect.h>
  22 #include <net/netfilter/nf_conntrack_helper.h>
  23 #include <linux/netfilter/nf_conntrack_sip.h>
  24
  25 MODULE_LICENSE("GPL");
  26 MODULE_AUTHOR("Christian Hentschel <chentschel@arnet.com.ar>");
  27 MODULE_DESCRIPTION("SIP connection tracking helper");
  28 MODULE_ALIAS("ip_conntrack_sip");
  29
  30 #define MAX_PORTS       8
  31 static unsigned short ports[MAX_PORTS];
  32 static unsigned int ports_c;
  33 module_param_array(ports, ushort, &ports_c, 0400);
  34 MODULE_PARM_DESC(ports, "port numbers of SIP servers");
  35
  36 static unsigned int sip_timeout __read_mostly = SIP_TIMEOUT;
  37 module_param(sip_timeout, uint, 0600);
  38 MODULE_PARM_DESC(sip_timeout, "timeout for the master SIP session");
  39
  40 static int sip_direct_signalling __read_mostly = 1;
  41 module_param(sip_direct_signalling, int, 0600);
  42 MODULE_PARM_DESC(sip_direct_signalling, "expect incoming calls from registrar "
  43                                         "only (default 1)");
  44
  45 static int sip_direct_media __read_mostly = 1;
  46 module_param(sip_direct_media, int, 0600);
  47 MODULE_PARM_DESC(sip_direct_media, "Expect Media streams between signalling "
  48                                    "endpoints only (default 1)");
  49
  50 unsigned int (*nf_nat_sip_hook)(struct sk_buff *skb,
  51                                 const char **dptr,
  52                                 unsigned int *datalen) __read_mostly;
  53 EXPORT_SYMBOL_GPL(nf_nat_sip_hook);
  54
  55 unsigned int (*nf_nat_sip_expect_hook)(struct sk_buff *skb,
  56                                        const char **dptr,
  57                                        unsigned int *datalen,
  58                                        struct nf_conntrack_expect *exp,
  59                                        unsigned int matchoff,
  60                                        unsigned int matchlen) __read_mostly;
  61 EXPORT_SYMBOL_GPL(nf_nat_sip_expect_hook);
  62
  63 unsigned int (*nf_nat_sdp_addr_hook)(struct sk_buff *skb,
  64                                      const char **dptr,
  65                                      unsigned int dataoff,
  66                                      unsigned int *datalen,
  67                                      enum sdp_header_types type,
  68                                      enum sdp_header_types term,
  69                                      const union nf_inet_addr *addr)
  70                                      __read_mostly;
  71 EXPORT_SYMBOL_GPL(nf_nat_sdp_addr_hook);
  72
  73 unsigned int (*nf_nat_sdp_session_hook)(struct sk_buff *skb,
  74                                         const char **dptr,
  75                                         unsigned int dataoff,
  76                                         unsigned int *datalen,
  77                                         const union nf_inet_addr *addr)
  78                                         __read_mostly;
  79 EXPORT_SYMBOL_GPL(nf_nat_sdp_session_hook);
  80
  81 unsigned int (*nf_nat_sdp_media_hook)(struct sk_buff *skb,
  82                                       const char **dptr,
  83                                       unsigned int *datalen,
  84                                       struct nf_conntrack_expect *rtp_exp,
  85                                       struct nf_conntrack_expect *rtcp_exp,
  86                                       unsigned int mediaoff,
  87                                       unsigned int medialen,
  88                                       union nf_inet_addr *rtp_addr)
  89                                       __read_mostly;
  90 EXPORT_SYMBOL_GPL(nf_nat_sdp_media_hook);
  91
  92 static int string_len(const struct nf_conn *ct, const char *dptr,
  93                       const char *limit, int *shift)
  94 {
  95         int len = 0;
  96
  97         while (dptr < limit && isalpha(*dptr)) {
  98                 dptr++;
  99                 len++;
 100         }
 101         return len;
 102 }
 103
 104 static int digits_len(const struct nf_conn *ct, const char *dptr,
 105                       const char *limit, int *shift)
 106 {
 107         int len = 0;
 108         while (dptr < limit && isdigit(*dptr)) {
 109                 dptr++;
 110                 len++;
 111         }
 112         return len;
 113 }
 114
 115 static int parse_addr(const struct nf_conn *ct, const char *cp,
 116                       const char **endp, union nf_inet_addr *addr,
 117                       const char *limit)
 118 {
 119         const char *end;
 120         int family = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
 121         int ret = 0;
 122
 123         switch (family) {
 124         case AF_INET:
 125                 ret = in4_pton(cp, limit - cp, (u8 *)&addr->ip, -1, &end);
 126                 break;
 127         case AF_INET6:
 128                 ret = in6_pton(cp, limit - cp, (u8 *)&addr->ip6, -1, &end);
 129                 break;
 130         default:
 131                 BUG();
 132         }
 133
 134         if (ret == 0 || end == cp)
 135                 return 0;
 136         if (endp)
 137                 *endp = end;
 138         return 1;
 139 }
 140
 141 /* skip ip address. returns its length. */
 142 static int epaddr_len(const struct nf_conn *ct, const char *dptr,
 143                       const char *limit, int *shift)
 144 {
 145         union nf_inet_addr addr;
 146         const char *aux = dptr;
 147
 148         if (!parse_addr(ct, dptr, &dptr, &addr, limit)) {
 149                 pr_debug("ip: %s parse failed.!\n", dptr);
 150                 return 0;
 151         }
 152
 153         /* Port number */
 154         if (*dptr == ':') {
 155                 dptr++;
 156                 dptr += digits_len(ct, dptr, limit, shift);
 157         }
 158         return dptr - aux;
 159 }
 160
 161 /* get address length, skiping user info. */
 162 static int skp_epaddr_len(const struct nf_conn *ct, const char *dptr,
 163                           const char *limit, int *shift)
 164 {
 165         const char *start = dptr;
 166         int s = *shift;
 167
 168         /* Search for @, but stop at the end of the line.
 169          * We are inside a sip: URI, so we don't need to worry about
 170          * continuation lines. */
 171         while (dptr < limit &&
 172                *dptr != '@' && *dptr != '\r' && *dptr != '\n') {
 173                 (*shift)++;
 174                 dptr++;
 175         }
 176
 177         if (dptr < limit && *dptr == '@') {
 178                 dptr++;
 179                 (*shift)++;
 180         } else {
 181                 dptr = start;
 182                 *shift = s;
 183         }
 184
 185         return epaddr_len(ct, dptr, limit, shift);
 186 }
 187
 188 /* Parse a SIP request line of the form:
 189  *
 190  * Request-Line = Method SP Request-URI SP SIP-Version CRLF
 191  *
 192  * and return the offset and length of the address contained in the Request-URI.
 193  */
 194 int ct_sip_parse_request(const struct nf_conn *ct,
 195                          const char *dptr, unsigned int datalen,
 196                          unsigned int *matchoff, unsigned int *matchlen,
 197                          union nf_inet_addr *addr, __be16 *port)
 198 {
 199         const char *start = dptr, *limit = dptr + datalen, *end;
 200         unsigned int mlen;
 201         unsigned int p;
 202         int shift = 0;
 203
 204         /* Skip method and following whitespace */
 205         mlen = string_len(ct, dptr, limit, NULL);
 206         if (!mlen)
 207                 return 0;
 208         dptr += mlen;
 209         if (++dptr >= limit)
 210                 return 0;
 211
 212         /* Find SIP URI */
 213         limit -= strlen("sip:");
 214         for (; dptr < limit; dptr++) {
 215                 if (*dptr == '\r' || *dptr == '\n')
 216                         return -1;
 217                 if (strnicmp(dptr, "sip:", strlen("sip:")) == 0)
 218                         break;
 219         }
 220         if (!skp_epaddr_len(ct, dptr, limit, &shift))
 221                 return 0;
 222         dptr += shift;
 223
 224         if (!parse_addr(ct, dptr, &end, addr, limit))
 225                 return -1;
 226         if (end < limit && *end == ':') {
 227                 end++;
 228                 p = simple_strtoul(end, (char **)&end, 10);
 229                 if (p < 1024 || p > 65535)
 230                         return -1;
 231                 *port = htons(p);
 232         } else
 233                 *port = htons(SIP_PORT);
 234
 235         if (end == dptr)
 236                 return 0;
 237         *matchoff = dptr - start;
 238         *matchlen = end - dptr;
 239         return 1;
 240 }
 241 EXPORT_SYMBOL_GPL(ct_sip_parse_request);
 242
 243 /* SIP header parsing: SIP headers are located at the beginning of a line, but
 244  * may span several lines, in which case the continuation lines begin with a
 245  * whitespace character. RFC 2543 allows lines to be terminated with CR, LF or
 246  * CRLF, RFC 3261 allows only CRLF, we support both.
 247  *
 248  * Headers are followed by (optionally) whitespace, a colon, again (optionally)
 249  * whitespace and the values. Whitespace in this context means any amount of
 250  * tabs, spaces and continuation lines, which are treated as a single whitespace
 251  * character.
 252  *
 253  * Some headers may appear multiple times. A comma seperated list of values is
 254  * equivalent to multiple headers.
 255  */
 256 static const struct sip_header ct_sip_hdrs[] = {
 257         [SIP_HDR_CSEQ]                  = SIP_HDR("CSeq", NULL, NULL, digits_len),
 258         [SIP_HDR_FROM]                  = SIP_HDR("From", "f", "sip:", skp_epaddr_len),
 259         [SIP_HDR_TO]                    = SIP_HDR("To", "t", "sip:", skp_epaddr_len),
 260         [SIP_HDR_CONTACT]               = SIP_HDR("Contact", "m", "sip:", skp_epaddr_len),
 261         [SIP_HDR_VIA]                   = SIP_HDR("Via", "v", "UDP ", epaddr_len),
 262         [SIP_HDR_EXPIRES]               = SIP_HDR("Expires", NULL, NULL, digits_len),
 263         [SIP_HDR_CONTENT_LENGTH]        = SIP_HDR("Content-Length", "l", NULL, digits_len),
 264 };
 265
 266 static const char *sip_follow_continuation(const char *dptr, const char *limit)
 267 {
 268         /* Walk past newline */
 269         if (++dptr >= limit)
 270                 return NULL;
 271
 272         /* Skip '\n' in CR LF */
 273         if (*(dptr - 1) == '\r' && *dptr == '\n') {
 274                 if (++dptr >= limit)
 275                         return NULL;
 276         }
 277
 278         /* Continuation line? */
 279         if (*dptr != ' ' && *dptr != '\t')
 280                 return NULL;
 281
 282         /* skip leading whitespace */
 283         for (; dptr < limit; dptr++) {
 284                 if (*dptr != ' ' && *dptr != '\t')
 285                         break;
 286         }
 287         return dptr;
 288 }
 289
 290 static const char *sip_skip_whitespace(const char *dptr, const char *limit)
 291 {
 292         for (; dptr < limit; dptr++) {
 293                 if (*dptr == ' ')
 294                         continue;
 295                 if (*dptr != '\r' && *dptr != '\n')
 296                         break;
 297                 dptr = sip_follow_continuation(dptr, limit);
 298                 if (dptr == NULL)
 299                         return NULL;
 300         }
 301         return dptr;
 302 }
 303
 304 /* Search within a SIP header value, dealing with continuation lines */
 305 static const char *ct_sip_header_search(const char *dptr, const char *limit,
 306                                         const char *needle, unsigned int len)
 307 {
 308         for (limit -= len; dptr < limit; dptr++) {
 309                 if (*dptr == '\r' || *dptr == '\n') {
 310                         dptr = sip_follow_continuation(dptr, limit);
 311                         if (dptr == NULL)
 312                                 break;
 313                         continue;
 314                 }
 315
 316                 if (strnicmp(dptr, needle, len) == 0)
 317                         return dptr;
 318         }
 319         return NULL;
 320 }
 321
 322 int ct_sip_get_header(const struct nf_conn *ct, const char *dptr,
 323                       unsigned int dataoff, unsigned int datalen,
 324                       enum sip_header_types type,
 325                       unsigned int *matchoff, unsigned int *matchlen)
 326 {
 327         const struct sip_header *hdr = &ct_sip_hdrs[type];
 328         const char *start = dptr, *limit = dptr + datalen;
 329         int shift = 0;
 330
 331         for (dptr += dataoff; dptr < limit; dptr++) {
 332                 /* Find beginning of line */
 333                 if (*dptr != '\r' && *dptr != '\n')
 334                         continue;
 335                 if (++dptr >= limit)
 336                         break;
 337                 if (*(dptr - 1) == '\r' && *dptr == '\n') {
 338                         if (++dptr >= limit)
 339                                 break;
 340                 }
 341
 342                 /* Skip continuation lines */
 343                 if (*dptr == ' ' || *dptr == '\t')
 344                         continue;
 345
 346                 /* Find header. Compact headers must be followed by a
 347                  * non-alphabetic character to avoid mismatches. */
 348                 if (limit - dptr >= hdr->len &&
 349                     strnicmp(dptr, hdr->name, hdr->len) == 0)
 350                         dptr += hdr->len;
 351                 else if (hdr->cname && limit - dptr >= hdr->clen + 1 &&
 352                          strnicmp(dptr, hdr->cname, hdr->clen) == 0 &&
 353                          !isalpha(*(dptr + hdr->clen + 1)))
 354                         dptr += hdr->clen;
 355                 else
 356                         continue;
 357
 358                 /* Find and skip colon */
 359                 dptr = sip_skip_whitespace(dptr, limit);
 360                 if (dptr == NULL)
 361                         break;
 362                 if (*dptr != ':' || ++dptr >= limit)
 363                         break;
 364
 365                 /* Skip whitespace after colon */
 366                 dptr = sip_skip_whitespace(dptr, limit);
 367                 if (dptr == NULL)
 368                         break;
 369
 370                 *matchoff = dptr - start;
 371                 if (hdr->search) {
 372                         dptr = ct_sip_header_search(dptr, limit, hdr->search,
 373                                                     hdr->slen);
 374                         if (!dptr)
 375                                 return -1;
 376                         dptr += hdr->slen;
 377                 }
 378
 379                 *matchlen = hdr->match_len(ct, dptr, limit, &shift);
 380                 if (!*matchlen)
 381                         return -1;
 382                 *matchoff = dptr - start + shift;
 383                 return 1;
 384         }
 385         return 0;
 386 }
 387 EXPORT_SYMBOL_GPL(ct_sip_get_header);
 388
 389 /* Get next header field in a list of comma seperated values */
 390 static int ct_sip_next_header(const struct nf_conn *ct, const char *dptr,
 391                               unsigned int dataoff, unsigned int datalen,
 392                               enum sip_header_types type,
 393                               unsigned int *matchoff, unsigned int *matchlen)
 394 {
 395         const struct sip_header *hdr = &ct_sip_hdrs[type];
 396         const char *start = dptr, *limit = dptr + datalen;
 397         int shift = 0;
 398
 399         dptr += dataoff;
 400
 401         dptr = ct_sip_header_search(dptr, limit, ",", strlen(","));
 402         if (!dptr)
 403                 return 0;
 404
 405         dptr = ct_sip_header_search(dptr, limit, hdr->search, hdr->slen);
 406         if (!dptr)
 407                 return 0;
 408         dptr += hdr->slen;
 409
 410         *matchoff = dptr - start;
 411         *matchlen = hdr->match_len(ct, dptr, limit, &shift);
 412         if (!*matchlen)
 413                 return -1;
 414         *matchoff += shift;
 415         return 1;
 416 }
 417
 418 /* Walk through headers until a parsable one is found or no header of the
 419  * given type is left. */
 420 static int ct_sip_walk_headers(const struct nf_conn *ct, const char *dptr,
 421                                unsigned int dataoff, unsigned int datalen,
 422                                enum sip_header_types type, int *in_header,
 423                                unsigned int *matchoff, unsigned int *matchlen)
 424 {
 425         int ret;
 426
 427         if (in_header && *in_header) {
 428                 while (1) {
 429                         ret = ct_sip_next_header(ct, dptr, dataoff, datalen,
 430                                                  type, matchoff, matchlen);
 431                         if (ret > 0)
 432                                 return ret;
 433                         if (ret == 0)
 434                                 break;
 435                         dataoff += *matchoff;
 436                 }
 437                 *in_header = 0;
 438         }
 439
 440         while (1) {
 441                 ret = ct_sip_get_header(ct, dptr, dataoff, datalen,
 442                                         type, matchoff, matchlen);
 443                 if (ret > 0)
 444                         break;
 445                 if (ret == 0)
 446                         return ret;
 447                 dataoff += *matchoff;
 448         }
 449
 450         if (in_header)
 451                 *in_header = 1;
 452         return 1;
 453 }
 454
 455 /* Locate a SIP header, parse the URI and return the offset and length of
 456  * the address as well as the address and port themselves. A stream of
 457  * headers can be parsed by handing in a non-NULL datalen and in_header
 458  * pointer.
 459  */
 460 int ct_sip_parse_header_uri(const struct nf_conn *ct, const char *dptr,
 461                             unsigned int *dataoff, unsigned int datalen,
 462                             enum sip_header_types type, int *in_header,
 463                             unsigned int *matchoff, unsigned int *matchlen,
 464                             union nf_inet_addr *addr, __be16 *port)
 465 {
 466         const char *c, *limit = dptr + datalen;
 467         unsigned int p;
 468         int ret;
 469
 470         ret = ct_sip_walk_headers(ct, dptr, dataoff ? *dataoff : 0, datalen,
 471                                   type, in_header, matchoff, matchlen);
 472         WARN_ON(ret < 0);
 473         if (ret == 0)
 474                 return ret;
 475
 476         if (!parse_addr(ct, dptr + *matchoff, &c, addr, limit))
 477                 return -1;
 478         if (*c == ':') {
 479                 c++;
 480                 p = simple_strtoul(c, (char **)&c, 10);
 481                 if (p < 1024 || p > 65535)
 482                         return -1;
 483                 *port = htons(p);
 484         } else
 485                 *port = htons(SIP_PORT);
 486
 487         if (dataoff)
 488                 *dataoff = c - dptr;
 489         return 1;
 490 }
 491 EXPORT_SYMBOL_GPL(ct_sip_parse_header_uri);
 492
 493 /* Parse address from header parameter and return address, offset and length */
 494 int ct_sip_parse_address_param(const struct nf_conn *ct, const char *dptr,
 495                                unsigned int dataoff, unsigned int datalen,
 496                                const char *name,
 497                                unsigned int *matchoff, unsigned int *matchlen,
 498                                union nf_inet_addr *addr)
 499 {
 500         const char *limit = dptr + datalen;
 501         const char *start, *end;
 502
 503         limit = ct_sip_header_search(dptr + dataoff, limit, ",", strlen(","));
 504         if (!limit)
 505                 limit = dptr + datalen;
 506
 507         start = ct_sip_header_search(dptr + dataoff, limit, name, strlen(name));
 508         if (!start)
 509                 return 0;
 510
 511         start += strlen(name);
 512         if (!parse_addr(ct, start, &end, addr, limit))
 513                 return 0;
 514         *matchoff = start - dptr;
 515         *matchlen = end - start;
 516         return 1;
 517 }
 518 EXPORT_SYMBOL_GPL(ct_sip_parse_address_param);
 519
 520 /* Parse numerical header parameter and return value, offset and length */
 521 int ct_sip_parse_numerical_param(const struct nf_conn *ct, const char *dptr,
 522                                  unsigned int dataoff, unsigned int datalen,
 523                                  const char *name,
 524                                  unsigned int *matchoff, unsigned int *matchlen,
 525                                  unsigned int *val)
 526 {
 527         const char *limit = dptr + datalen;
 528         const char *start;
 529         char *end;
 530
 531         limit = ct_sip_header_search(dptr + dataoff, limit, ",", strlen(","));
 532         if (!limit)
 533                 limit = dptr + datalen;
 534
 535         start = ct_sip_header_search(dptr + dataoff, limit, name, strlen(name));
 536         if (!start)
 537                 return 0;
 538
 539         start += strlen(name);
 540         *val = simple_strtoul(start, &end, 0);
 541         if (start == end)
 542                 return 0;
 543         if (matchoff && matchlen) {
 544                 *matchoff = start - dptr;
 545                 *matchlen = end - start;
 546         }
 547         return 1;
 548 }
 549 EXPORT_SYMBOL_GPL(ct_sip_parse_numerical_param);
 550
 551 /* SDP header parsing: a SDP session description contains an ordered set of
 552  * headers, starting with a section containing general session parameters,
 553  * optionally followed by multiple media descriptions.
 554  *
 555  * SDP headers always start at the beginning of a line. According to RFC 2327:
 556  * "The sequence CRLF (0x0d0a) is used to end a record, although parsers should
 557  * be tolerant and also accept records terminated with a single newline
 558  * character". We handle both cases.
 559  */
 560 static const struct sip_header ct_sdp_hdrs[] = {
 561         [SDP_HDR_VERSION]               = SDP_HDR("v=", NULL, digits_len),
 562         [SDP_HDR_OWNER_IP4]             = SDP_HDR("o=", "IN IP4 ", epaddr_len),
 563         [SDP_HDR_CONNECTION_IP4]        = SDP_HDR("c=", "IN IP4 ", epaddr_len),
 564         [SDP_HDR_OWNER_IP6]             = SDP_HDR("o=", "IN IP6 ", epaddr_len),
 565         [SDP_HDR_CONNECTION_IP6]        = SDP_HDR("c=", "IN IP6 ", epaddr_len),
 566         [SDP_HDR_MEDIA]                 = SDP_HDR("m=", "audio ", digits_len),
 567 };
 568
 569 /* Linear string search within SDP header values */
 570 static const char *ct_sdp_header_search(const char *dptr, const char *limit,
 571                                         const char *needle, unsigned int len)
 572 {
 573         for (limit -= len; dptr < limit; dptr++) {
 574                 if (*dptr == '\r' || *dptr == '\n')
 575                         break;
 576                 if (strncmp(dptr, needle, len) == 0)
 577                         return dptr;
 578         }
 579         return NULL;
 580 }
 581
 582 /* Locate a SDP header (optionally a substring within the header value),
 583  * optionally stopping at the first occurence of the term header, parse
 584  * it and return the offset and length of the data we're interested in.
 585  */
 586 int ct_sip_get_sdp_header(const struct nf_conn *ct, const char *dptr,
 587                           unsigned int dataoff, unsigned int datalen,
 588                           enum sdp_header_types type,
 589                           enum sdp_header_types term,
 590                           unsigned int *matchoff, unsigned int *matchlen)
 591 {
 592         const struct sip_header *hdr = &ct_sdp_hdrs[type];
 593         const struct sip_header *thdr = &ct_sdp_hdrs[term];
 594         const char *start = dptr, *limit = dptr + datalen;
 595         int shift = 0;
 596
 597         for (dptr += dataoff; dptr < limit; dptr++) {
 598                 /* Find beginning of line */
 599                 if (*dptr != '\r' && *dptr != '\n')
 600                         continue;
 601                 if (++dptr >= limit)
 602                         break;
 603                 if (*(dptr - 1) == '\r' && *dptr == '\n') {
 604                         if (++dptr >= limit)
 605                                 break;
 606                 }
 607
 608                 if (term != SDP_HDR_UNSPEC &&
 609                     limit - dptr >= thdr->len &&
 610                     strnicmp(dptr, thdr->name, thdr->len) == 0)
 611                         break;
 612                 else if (limit - dptr >= hdr->len &&
 613                          strnicmp(dptr, hdr->name, hdr->len) == 0)
 614                         dptr += hdr->len;
 615                 else
 616                         continue;
 617
 618                 *matchoff = dptr - start;
 619                 if (hdr->search) {
 620                         dptr = ct_sdp_header_search(dptr, limit, hdr->search,
 621                                                     hdr->slen);
 622                         if (!dptr)
 623                                 return -1;
 624                         dptr += hdr->slen;
 625                 }
 626
 627                 *matchlen = hdr->match_len(ct, dptr, limit, &shift);
 628                 if (!*matchlen)
 629                         return -1;
 630                 *matchoff = dptr - start + shift;
 631                 return 1;
 632         }
 633         return 0;
 634 }
 635 EXPORT_SYMBOL_GPL(ct_sip_get_sdp_header);
 636
 637 static int ct_sip_parse_sdp_addr(const struct nf_conn *ct, const char *dptr,
 638                                  unsigned int dataoff, unsigned int datalen,
 639                                  enum sdp_header_types type,
 640                                  enum sdp_header_types term,
 641                                  unsigned int *matchoff, unsigned int *matchlen,
 642                                  union nf_inet_addr *addr)
 643 {
 644         int ret;
 645
 646         ret = ct_sip_get_sdp_header(ct, dptr, dataoff, datalen, type, term,
 647                                     matchoff, matchlen);
 648         if (ret <= 0)
 649                 return ret;
 650
 651         if (!parse_addr(ct, dptr + *matchoff, NULL, addr,
 652                         dptr + *matchoff + *matchlen))
 653                 return -1;
 654         return 1;
 655 }
 656
 657 static int refresh_signalling_expectation(struct nf_conn *ct,
 658                                           union nf_inet_addr *addr,
 659                                           __be16 port,
 660                                           unsigned int expires)
 661 {
 662         struct nf_conn_help *help = nfct_help(ct);
 663         struct nf_conntrack_expect *exp;
 664         struct hlist_node *n, *next;
 665         int found = 0;
 666
 667         spin_lock_bh(&nf_conntrack_lock);
 668         hlist_for_each_entry_safe(exp, n, next, &help->expectations, lnode) {
 669                 if (exp->class != SIP_EXPECT_SIGNALLING ||
 670                     !nf_inet_addr_cmp(&exp->tuple.dst.u3, addr) ||
 671                     exp->tuple.dst.u.udp.port != port)
 672                         continue;
 673                 if (!del_timer(&exp->timeout))
 674                         continue;
 675                 exp->flags &= ~NF_CT_EXPECT_INACTIVE;
 676                 exp->timeout.expires = jiffies + expires * HZ;
 677                 add_timer(&exp->timeout);
 678                 found = 1;
 679                 break;
 680         }
 681         spin_unlock_bh(&nf_conntrack_lock);
 682         return found;
 683 }
 684
 685 static void flush_expectations(struct nf_conn *ct, bool media)
 686 {
 687         struct nf_conn_help *help = nfct_help(ct);
 688         struct nf_conntrack_expect *exp;
 689         struct hlist_node *n, *next;
 690
 691         spin_lock_bh(&nf_conntrack_lock);
 692         hlist_for_each_entry_safe(exp, n, next, &help->expectations, lnode) {
 693                 if ((exp->class != SIP_EXPECT_SIGNALLING) ^ media)
 694                         continue;
 695                 if (!del_timer(&exp->timeout))
 696                         continue;
 697                 nf_ct_unlink_expect(exp);
 698                 nf_ct_expect_put(exp);
 699                 if (!media)
 700                         break;
 701         }
 702         spin_unlock_bh(&nf_conntrack_lock);
 703 }
 704
 705 static int set_expected_rtp_rtcp(struct sk_buff *skb,
 706                                  const char **dptr, unsigned int *datalen,
 707                                  union nf_inet_addr *daddr, __be16 port,
 708                                  unsigned int mediaoff, unsigned int medialen)
 709 {
 710         struct nf_conntrack_expect *exp, *rtp_exp, *rtcp_exp;
 711         enum ip_conntrack_info ctinfo;
 712         struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
 713         enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
 714         union nf_inet_addr *saddr;
 715         struct nf_conntrack_tuple tuple;
 716         int family = ct->tuplehash[!dir].tuple.src.l3num;
 717         int skip_expect = 0, ret = NF_DROP;
 718         u_int16_t base_port;
 719         __be16 rtp_port, rtcp_port;
 720         typeof(nf_nat_sdp_media_hook) nf_nat_sdp_media;
 721
 722         saddr = NULL;
 723         if (sip_direct_media) {
 724                 if (!nf_inet_addr_cmp(daddr, &ct->tuplehash[dir].tuple.src.u3))
 725                         return NF_ACCEPT;
 726                 saddr = &ct->tuplehash[!dir].tuple.src.u3;
 727         }
 728
 729         /* We need to check whether the registration exists before attempting
 730          * to register it since we can see the same media description multiple
 731          * times on different connections in case multiple endpoints receive
 732          * the same call.
 733          */
 734         memset(&tuple, 0, sizeof(tuple));
 735         if (saddr)
 736                 tuple.src.u3 = *saddr;
 737         tuple.src.l3num         = family;
 738         tuple.dst.protonum      = IPPROTO_UDP;
 739         tuple.dst.u3            = *daddr;
 740         tuple.dst.u.udp.port    = port;
 741
 742         rcu_read_lock();
 743         exp = __nf_ct_expect_find(&tuple);
 744         if (exp && exp->master != ct &&
 745             nfct_help(exp->master)->helper == nfct_help(ct)->helper &&
 746             exp->class == SIP_EXPECT_AUDIO)
 747                 skip_expect = 1;
 748         rcu_read_unlock();
 749
 750         if (skip_expect)
 751                 return NF_ACCEPT;
 752
 753         base_port = ntohs(tuple.dst.u.udp.port) & ~1;
 754         rtp_port = htons(base_port);
 755         rtcp_port = htons(base_port + 1);
 756
 757         rtp_exp = nf_ct_expect_alloc(ct);
 758         if (rtp_exp == NULL)
 759                 goto err1;
 760         nf_ct_expect_init(rtp_exp, SIP_EXPECT_AUDIO, family, saddr, daddr,
 761                           IPPROTO_UDP, NULL, &rtp_port);
 762
 763         rtcp_exp = nf_ct_expect_alloc(ct);
 764         if (rtcp_exp == NULL)
 765                 goto err2;
 766         nf_ct_expect_init(rtcp_exp, SIP_EXPECT_AUDIO, family, saddr, daddr,
 767                           IPPROTO_UDP, NULL, &rtcp_port);
 768
 769         nf_nat_sdp_media = rcu_dereference(nf_nat_sdp_media_hook);
 770         if (nf_nat_sdp_media && ct->status & IPS_NAT_MASK)
 771                 ret = nf_nat_sdp_media(skb, dptr, datalen, rtp_exp, rtcp_exp,
 772                                        mediaoff, medialen, daddr);
 773         else {
 774                 if (nf_ct_expect_related(rtp_exp) == 0) {
 775                         if (nf_ct_expect_related(rtcp_exp) != 0)
 776                                 nf_ct_unexpect_related(rtp_exp);
 777                         else
 778                                 ret = NF_ACCEPT;
 779                 }
 780         }
 781         nf_ct_expect_put(rtcp_exp);
 782 err2:
 783         nf_ct_expect_put(rtp_exp);
 784 err1:
 785         return ret;
 786 }
 787
 788 static int process_sdp(struct sk_buff *skb,
 789                        const char **dptr, unsigned int *datalen,
 790                        unsigned int cseq)
 791 {
 792         enum ip_conntrack_info ctinfo;
 793         struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
 794         int family = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
 795         unsigned int matchoff, matchlen;
 796         unsigned int mediaoff, medialen;
 797         unsigned int sdpoff;
 798         unsigned int caddr_len, maddr_len;
 799         union nf_inet_addr caddr, maddr, rtp_addr;
 800         unsigned int port;
 801         enum sdp_header_types c_hdr;
 802         int ret;
 803         typeof(nf_nat_sdp_addr_hook) nf_nat_sdp_addr;
 804         typeof(nf_nat_sdp_session_hook) nf_nat_sdp_session;
 805
 806         c_hdr = family == AF_INET ? SDP_HDR_CONNECTION_IP4 :
 807                                     SDP_HDR_CONNECTION_IP6;
 808
 809         /* Find beginning of session description */
 810         if (ct_sip_get_sdp_header(ct, *dptr, 0, *datalen,
 811                                   SDP_HDR_VERSION, SDP_HDR_UNSPEC,
 812                                   &matchoff, &matchlen) <= 0)
 813                 return NF_ACCEPT;
 814         sdpoff = matchoff;
 815
 816         /* The connection information is contained in the session description
 817          * and/or once per media description. The first media description marks
 818          * the end of the session description. */
 819         caddr_len = 0;
 820         if (ct_sip_parse_sdp_addr(ct, *dptr, sdpoff, *datalen,
 821                                   c_hdr, SDP_HDR_MEDIA,
 822                                   &matchoff, &matchlen, &caddr) > 0)
 823                 caddr_len = matchlen;
 824
 825         if (ct_sip_get_sdp_header(ct, *dptr, sdpoff, *datalen,
 826                                   SDP_HDR_MEDIA, SDP_HDR_UNSPEC,
 827                                   &mediaoff, &medialen) <= 0)
 828                 return NF_ACCEPT;
 829
 830         port = simple_strtoul(*dptr + mediaoff, NULL, 10);
 831         if (port < 1024 || port > 65535)
 832                 return NF_DROP;
 833
 834         /* The media description overrides the session description. */
 835         maddr_len = 0;
 836         if (ct_sip_parse_sdp_addr(ct, *dptr, mediaoff, *datalen,
 837                                   c_hdr, SDP_HDR_MEDIA,
 838                                   &matchoff, &matchlen, &maddr) > 0) {
 839                 maddr_len = matchlen;
 840                 memcpy(&rtp_addr, &maddr, sizeof(rtp_addr));
 841         } else if (caddr_len)
 842                 memcpy(&rtp_addr, &caddr, sizeof(rtp_addr));
 843         else
 844                 return NF_DROP;
 845
 846         ret = set_expected_rtp_rtcp(skb, dptr, datalen, &rtp_addr, htons(port),
 847                                     mediaoff, medialen);
 848         if (ret != NF_ACCEPT)
 849                 return ret;
 850
 851         /* Update media connection address if present */
 852         if (maddr_len) {
 853                 nf_nat_sdp_addr = rcu_dereference(nf_nat_sdp_addr_hook);
 854                 if (nf_nat_sdp_addr && ct->status & IPS_NAT_MASK) {
 855                         ret = nf_nat_sdp_addr(skb, dptr, mediaoff, datalen,
 856                                               c_hdr, SDP_HDR_MEDIA, &rtp_addr);
 857                         if (ret != NF_ACCEPT)
 858                                 return ret;
 859                 }
 860         }
 861
 862         /* Update session connection and owner addresses */
 863         nf_nat_sdp_session = rcu_dereference(nf_nat_sdp_session_hook);
 864         if (nf_nat_sdp_session && ct->status & IPS_NAT_MASK)
 865                 ret = nf_nat_sdp_session(skb, dptr, sdpoff, datalen, &rtp_addr);
 866
 867         return ret;
 868 }
 869 static int process_invite_response(struct sk_buff *skb,
 870                                    const char **dptr, unsigned int *datalen,
 871                                    unsigned int cseq, unsigned int code)
 872 {
 873         enum ip_conntrack_info ctinfo;
 874         struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
 875
 876         if ((code >= 100 && code <= 199) ||
 877             (code >= 200 && code <= 299))
 878                 return process_sdp(skb, dptr, datalen, cseq);
 879         else {
 880                 flush_expectations(ct, true);
 881                 return NF_ACCEPT;
 882         }
 883 }
 884
 885 static int process_update_response(struct sk_buff *skb,
 886                                    const char **dptr, unsigned int *datalen,
 887                                    unsigned int cseq, unsigned int code)
 888 {
 889         enum ip_conntrack_info ctinfo;
 890         struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
 891
 892         if ((code >= 100 && code <= 199) ||
 893             (code >= 200 && code <= 299))
 894                 return process_sdp(skb, dptr, datalen, cseq);
 895         else {
 896                 flush_expectations(ct, true);
 897                 return NF_ACCEPT;
 898         }
 899 }
 900
 901 static int process_prack_response(struct sk_buff *skb,
 902                                   const char **dptr, unsigned int *datalen,
 903                                   unsigned int cseq, unsigned int code)
 904 {
 905         enum ip_conntrack_info ctinfo;
 906         struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
 907
 908         if ((code >= 100 && code <= 199) ||
 909             (code >= 200 && code <= 299))
 910                 return process_sdp(skb, dptr, datalen, cseq);
 911         else {
 912                 flush_expectations(ct, true);
 913                 return NF_ACCEPT;
 914         }
 915 }
 916
 917 static int process_bye_request(struct sk_buff *skb,
 918                                const char **dptr, unsigned int *datalen,
 919                                unsigned int cseq)
 920 {
 921         enum ip_conntrack_info ctinfo;
 922         struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
 923
 924         flush_expectations(ct, true);
 925         return NF_ACCEPT;
 926 }
 927
 928 /* Parse a REGISTER request and create a permanent expectation for incoming
 929  * signalling connections. The expectation is marked inactive and is activated
 930  * when receiving a response indicating success from the registrar.
 931  */
 932 static int process_register_request(struct sk_buff *skb,
 933                                     const char **dptr, unsigned int *datalen,
 934                                     unsigned int cseq)
 935 {
 936         enum ip_conntrack_info ctinfo;
 937         struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
 938         struct nf_conn_help *help = nfct_help(ct);
 939         enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
 940         int family = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
 941         unsigned int matchoff, matchlen;
 942         struct nf_conntrack_expect *exp;
 943         union nf_inet_addr *saddr, daddr;
 944         __be16 port;
 945         unsigned int expires = 0;
 946         int ret;
 947         typeof(nf_nat_sip_expect_hook) nf_nat_sip_expect;
 948
 949         /* Expected connections can not register again. */
 950         if (ct->status & IPS_EXPECTED)
 951                 return NF_ACCEPT;
 952
 953         /* We must check the expiration time: a value of zero signals the
 954          * registrar to release the binding. We'll remove our expectation
 955          * when receiving the new bindings in the response, but we don't
 956          * want to create new ones.
 957          *
 958          * The expiration time may be contained in Expires: header, the
 959          * Contact: header parameters or the URI parameters.
 960          */
 961         if (ct_sip_get_header(ct, *dptr, 0, *datalen, SIP_HDR_EXPIRES,
 962                               &matchoff, &matchlen) > 0)
 963                 expires = simple_strtoul(*dptr + matchoff, NULL, 10);
 964
 965         ret = ct_sip_parse_header_uri(ct, *dptr, NULL, *datalen,
 966                                       SIP_HDR_CONTACT, NULL,
 967                                       &matchoff, &matchlen, &daddr, &port);
 968         if (ret < 0)
 969                 return NF_DROP;
 970         else if (ret == 0)
 971                 return NF_ACCEPT;
 972
 973         /* We don't support third-party registrations */
 974         if (!nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.src.u3, &daddr))
 975                 return NF_ACCEPT;
 976
 977         if (ct_sip_parse_numerical_param(ct, *dptr,
 978                                          matchoff + matchlen, *datalen,
 979                                          "expires=", NULL, NULL, &expires) < 0)
 980                 return NF_DROP;
 981
 982         if (expires == 0) {
 983                 ret = NF_ACCEPT;
 984                 goto store_cseq;
 985         }
 986
 987         exp = nf_ct_expect_alloc(ct);
 988         if (!exp)
 989                 return NF_DROP;
 990
 991         saddr = NULL;
 992         if (sip_direct_signalling)
 993                 saddr = &ct->tuplehash[!dir].tuple.src.u3;
 994
 995         nf_ct_expect_init(exp, SIP_EXPECT_SIGNALLING, family, saddr, &daddr,
 996                           IPPROTO_UDP, NULL, &port);
 997         exp->timeout.expires = sip_timeout * HZ;
 998         exp->helper = nfct_help(ct)->helper;
 999         exp->flags = NF_CT_EXPECT_PERMANENT | NF_CT_EXPECT_INACTIVE;
1000
1001         nf_nat_sip_expect = rcu_dereference(nf_nat_sip_expect_hook);
1002         if (nf_nat_sip_expect && ct->status & IPS_NAT_MASK)
1003                 ret = nf_nat_sip_expect(skb, dptr, datalen, exp,
1004                                         matchoff, matchlen);
1005         else {
1006                 if (nf_ct_expect_related(exp) != 0)
1007                         ret = NF_DROP;
1008                 else
1009                         ret = NF_ACCEPT;
1010         }
1011         nf_ct_expect_put(exp);
1012
1013 store_cseq:
1014         if (ret == NF_ACCEPT)
1015                 help->help.ct_sip_info.register_cseq = cseq;
1016         return ret;
1017 }
1018
1019 static int process_register_response(struct sk_buff *skb,
1020                                      const char **dptr, unsigned int *datalen,
1021                                      unsigned int cseq, unsigned int code)
1022 {
1023         enum ip_conntrack_info ctinfo;
1024         struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
1025         struct nf_conn_help *help = nfct_help(ct);
1026         enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
1027         union nf_inet_addr addr;
1028         __be16 port;
1029         unsigned int matchoff, matchlen, dataoff = 0;
1030         unsigned int expires = 0;
1031         int in_contact = 0, ret;
1032
1033         /* According to RFC 3261, "UAs MUST NOT send a new registration until
1034          * they have received a final response from the registrar for the
1035          * previous one or the previous REGISTER request has timed out".
1036          *
1037          * However, some servers fail to detect retransmissions and send late
1038          * responses, so we store the sequence number of the last valid
1039          * request and compare it here.
1040          */
1041         if (help->help.ct_sip_info.register_cseq != cseq)
1042                 return NF_ACCEPT;
1043
1044         if (code >= 100 && code <= 199)
1045                 return NF_ACCEPT;
1046         if (code < 200 || code > 299)
1047                 goto flush;
1048
1049         if (ct_sip_get_header(ct, *dptr, 0, *datalen, SIP_HDR_EXPIRES,
1050                               &matchoff, &matchlen) > 0)
1051                 expires = simple_strtoul(*dptr + matchoff, NULL, 10);
1052
1053         while (1) {
1054                 unsigned int c_expires = expires;
1055
1056                 ret = ct_sip_parse_header_uri(ct, *dptr, &dataoff, *datalen,
1057                                               SIP_HDR_CONTACT, &in_contact,
1058                                               &matchoff, &matchlen,
1059                                               &addr, &port);
1060                 if (ret < 0)
1061                         return NF_DROP;
1062                 else if (ret == 0)
1063                         break;
1064
1065                 /* We don't support third-party registrations */
1066                 if (!nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.dst.u3, &addr))
1067                         continue;
1068
1069                 ret = ct_sip_parse_numerical_param(ct, *dptr,
1070                                                    matchoff + matchlen,
1071                                                    *datalen, "expires=",
1072                                                    NULL, NULL, &c_expires);
1073                 if (ret < 0)
1074                         return NF_DROP;
1075                 if (c_expires == 0)
1076                         break;
1077                 if (refresh_signalling_expectation(ct, &addr, port, c_expires))
1078                         return NF_ACCEPT;
1079         }
1080
1081 flush:
1082         flush_expectations(ct, false);
1083         return NF_ACCEPT;
1084 }
1085
1086 static const struct sip_handler sip_handlers[] = {
1087         SIP_HANDLER("INVITE", process_sdp, process_invite_response),
1088         SIP_HANDLER("UPDATE", process_sdp, process_update_response),
1089         SIP_HANDLER("ACK", process_sdp, NULL),
1090         SIP_HANDLER("PRACK", process_sdp, process_prack_response),
1091         SIP_HANDLER("BYE", process_bye_request, NULL),
1092         SIP_HANDLER("REGISTER", process_register_request, process_register_response),
1093 };
1094
1095 static int process_sip_response(struct sk_buff *skb,
1096                                 const char **dptr, unsigned int *datalen)
1097 {
1098         static const struct sip_handler *handler;
1099         enum ip_conntrack_info ctinfo;
1100         struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
1101         unsigned int matchoff, matchlen;
1102         unsigned int code, cseq, dataoff, i;
1103
1104         if (*datalen < strlen("SIP/2.0 200"))
1105                 return NF_ACCEPT;
1106         code = simple_strtoul(*dptr + strlen("SIP/2.0 "), NULL, 10);
1107         if (!code)
1108                 return NF_DROP;
1109
1110         if (ct_sip_get_header(ct, *dptr, 0, *datalen, SIP_HDR_CSEQ,
1111                               &matchoff, &matchlen) <= 0)
1112                 return NF_DROP;
1113         cseq = simple_strtoul(*dptr + matchoff, NULL, 10);
1114         if (!cseq)
1115                 return NF_DROP;
1116         dataoff = matchoff + matchlen + 1;
1117
1118         for (i = 0; i < ARRAY_SIZE(sip_handlers); i++) {
1119                 handler = &sip_handlers[i];
1120                 if (handler->response == NULL)
1121                         continue;
1122                 if (*datalen < dataoff + handler->len ||
1123                     strnicmp(*dptr + dataoff, handler->method, handler->len))
1124                         continue;
1125                 return handler->response(skb, dptr, datalen, cseq, code);
1126         }
1127         return NF_ACCEPT;
1128 }
1129
1130 static int process_sip_request(struct sk_buff *skb,
1131                                const char **dptr, unsigned int *datalen)
1132 {
1133         static const struct sip_handler *handler;
1134         enum ip_conntrack_info ctinfo;
1135         struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
1136         unsigned int matchoff, matchlen;
1137         unsigned int cseq, i;
1138
1139         for (i = 0; i < ARRAY_SIZE(sip_handlers); i++) {
1140                 handler = &sip_handlers[i];
1141                 if (handler->request == NULL)
1142                         continue;
1143                 if (*datalen < handler->len ||
1144                     strnicmp(*dptr, handler->method, handler->len))
1145                         continue;
1146
1147                 if (ct_sip_get_header(ct, *dptr, 0, *datalen, SIP_HDR_CSEQ,
1148                                       &matchoff, &matchlen) <= 0)
1149                         return NF_DROP;
1150                 cseq = simple_strtoul(*dptr + matchoff, NULL, 10);
1151                 if (!cseq)
1152                         return NF_DROP;
1153
1154                 return handler->request(skb, dptr, datalen, cseq);
1155         }
1156         return NF_ACCEPT;
1157 }
1158
1159 static int sip_help(struct sk_buff *skb,
1160                     unsigned int protoff,
1161                     struct nf_conn *ct,
1162                     enum ip_conntrack_info ctinfo)
1163 {
1164         unsigned int dataoff, datalen;
1165         const char *dptr;
1166         int ret;
1167         typeof(nf_nat_sip_hook) nf_nat_sip;
1168
1169         /* No Data ? */
1170         dataoff = protoff + sizeof(struct udphdr);
1171         if (dataoff >= skb->len)
1172                 return NF_ACCEPT;
1173
1174         nf_ct_refresh(ct, skb, sip_timeout * HZ);
1175
1176         if (!skb_is_nonlinear(skb))
1177                 dptr = skb->data + dataoff;
1178         else {
1179                 pr_debug("Copy of skbuff not supported yet.\n");
1180                 return NF_ACCEPT;
1181         }
1182
1183         datalen = skb->len - dataoff;
1184         if (datalen < strlen("SIP/2.0 200"))
1185                 return NF_ACCEPT;
1186
1187         if (strnicmp(dptr, "SIP/2.0 ", strlen("SIP/2.0 ")) != 0)
1188                 ret = process_sip_request(skb, &dptr, &datalen);
1189         else
1190                 ret = process_sip_response(skb, &dptr, &datalen);
1191
1192         if (ret == NF_ACCEPT && ct->status & IPS_NAT_MASK) {
1193                 nf_nat_sip = rcu_dereference(nf_nat_sip_hook);
1194                 if (nf_nat_sip && !nf_nat_sip(skb, &dptr, &datalen))
1195                         ret = NF_DROP;
1196         }
1197
1198         return ret;
1199 }
1200
1201 static struct nf_conntrack_helper sip[MAX_PORTS][2] __read_mostly;
1202 static char sip_names[MAX_PORTS][2][sizeof("sip-65535")] __read_mostly;
1203
1204 static const struct nf_conntrack_expect_policy sip_exp_policy[SIP_EXPECT_MAX + 1] = {
1205         [SIP_EXPECT_SIGNALLING] = {
1206                 .max_expected   = 1,
1207                 .timeout        = 3 * 60,
1208         },
1209         [SIP_EXPECT_AUDIO] = {
1210                 .max_expected   = 2 * IP_CT_DIR_MAX,
1211                 .timeout        = 3 * 60,
1212         },
1213 };
1214
1215 static void nf_conntrack_sip_fini(void)
1216 {
1217         int i, j;
1218
1219         for (i = 0; i < ports_c; i++) {
1220                 for (j = 0; j < 2; j++) {
1221                         if (sip[i][j].me == NULL)
1222                                 continue;
1223                         nf_conntrack_helper_unregister(&sip[i][j]);
1224                 }
1225         }
1226 }
1227
1228 static int __init nf_conntrack_sip_init(void)
1229 {
1230         int i, j, ret;
1231         char *tmpname;
1232
1233         if (ports_c == 0)
1234                 ports[ports_c++] = SIP_PORT;
1235
1236         for (i = 0; i < ports_c; i++) {
1237                 memset(&sip[i], 0, sizeof(sip[i]));
1238
1239                 sip[i][0].tuple.src.l3num = AF_INET;
1240                 sip[i][1].tuple.src.l3num = AF_INET6;
1241                 for (j = 0; j < 2; j++) {
1242                         sip[i][j].tuple.dst.protonum = IPPROTO_UDP;
1243                         sip[i][j].tuple.src.u.udp.port = htons(ports[i]);
1244                         sip[i][j].expect_policy = sip_exp_policy;
1245                         sip[i][j].expect_class_max = SIP_EXPECT_MAX;
1246                         sip[i][j].me = THIS_MODULE;
1247                         sip[i][j].help = sip_help;
1248
1249                         tmpname = &sip_names[i][j][0];
1250                         if (ports[i] == SIP_PORT)
1251                                 sprintf(tmpname, "sip");
1252                         else
1253                                 sprintf(tmpname, "sip-%u", i);
1254                         sip[i][j].name = tmpname;
1255
1256                         pr_debug("port #%u: %u\n", i, ports[i]);
1257
1258                         ret = nf_conntrack_helper_register(&sip[i][j]);
1259                         if (ret) {
1260                                 printk("nf_ct_sip: failed to register helper "
1261                                        "for pf: %u port: %u\n",
1262                                        sip[i][j].tuple.src.l3num, ports[i]);
1263                                 nf_conntrack_sip_fini();
1264                                 return ret;
1265                         }
1266                 }
1267         }
1268         return 0;
1269 }
1270
1271 module_init(nf_conntrack_sip_init);
1272 module_exit(nf_conntrack_sip_fini);