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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 | * (C) 2007 United Security Providers | |
6 | * (C) 2007, 2008 Patrick McHardy <kaber@trash.net> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | */ | |
12 | ||
13 | #include <linux/module.h> | |
14 | #include <linux/ctype.h> | |
15 | #include <linux/skbuff.h> | |
16 | #include <linux/inet.h> | |
17 | #include <linux/in.h> | |
18 | #include <linux/udp.h> | |
19 | #include <linux/tcp.h> | |
20 | #include <linux/netfilter.h> | |
21 | ||
22 | #include <net/netfilter/nf_conntrack.h> | |
23 | #include <net/netfilter/nf_conntrack_core.h> | |
24 | #include <net/netfilter/nf_conntrack_expect.h> | |
25 | #include <net/netfilter/nf_conntrack_helper.h> | |
26 | #include <net/netfilter/nf_conntrack_zones.h> | |
27 | #include <linux/netfilter/nf_conntrack_sip.h> | |
28 | ||
29 | MODULE_LICENSE("GPL"); | |
30 | MODULE_AUTHOR("Christian Hentschel <chentschel@arnet.com.ar>"); | |
31 | MODULE_DESCRIPTION("SIP connection tracking helper"); | |
32 | MODULE_ALIAS("ip_conntrack_sip"); | |
33 | MODULE_ALIAS_NFCT_HELPER("sip"); | |
34 | ||
35 | #define MAX_PORTS 8 | |
36 | static unsigned short ports[MAX_PORTS]; | |
37 | static unsigned int ports_c; | |
38 | module_param_array(ports, ushort, &ports_c, 0400); | |
39 | MODULE_PARM_DESC(ports, "port numbers of SIP servers"); | |
40 | ||
41 | static unsigned int sip_timeout __read_mostly = SIP_TIMEOUT; | |
42 | module_param(sip_timeout, uint, 0600); | |
43 | MODULE_PARM_DESC(sip_timeout, "timeout for the master SIP session"); | |
44 | ||
45 | static int sip_direct_signalling __read_mostly = 1; | |
46 | module_param(sip_direct_signalling, int, 0600); | |
47 | MODULE_PARM_DESC(sip_direct_signalling, "expect incoming calls from registrar " | |
48 | "only (default 1)"); | |
49 | ||
50 | static int sip_direct_media __read_mostly = 1; | |
51 | module_param(sip_direct_media, int, 0600); | |
52 | MODULE_PARM_DESC(sip_direct_media, "Expect Media streams between signalling " | |
53 | "endpoints only (default 1)"); | |
54 | ||
55 | unsigned int (*nf_nat_sip_hook)(struct sk_buff *skb, unsigned int dataoff, | |
56 | const char **dptr, | |
57 | unsigned int *datalen) __read_mostly; | |
58 | EXPORT_SYMBOL_GPL(nf_nat_sip_hook); | |
59 | ||
60 | void (*nf_nat_sip_seq_adjust_hook)(struct sk_buff *skb, s16 off) __read_mostly; | |
61 | EXPORT_SYMBOL_GPL(nf_nat_sip_seq_adjust_hook); | |
62 | ||
63 | unsigned int (*nf_nat_sip_expect_hook)(struct sk_buff *skb, | |
64 | unsigned int dataoff, | |
65 | const char **dptr, | |
66 | unsigned int *datalen, | |
67 | struct nf_conntrack_expect *exp, | |
68 | unsigned int matchoff, | |
69 | unsigned int matchlen) __read_mostly; | |
70 | EXPORT_SYMBOL_GPL(nf_nat_sip_expect_hook); | |
71 | ||
72 | unsigned int (*nf_nat_sdp_addr_hook)(struct sk_buff *skb, unsigned int dataoff, | |
73 | const char **dptr, | |
74 | unsigned int *datalen, | |
75 | unsigned int sdpoff, | |
76 | enum sdp_header_types type, | |
77 | enum sdp_header_types term, | |
78 | const union nf_inet_addr *addr) | |
79 | __read_mostly; | |
80 | EXPORT_SYMBOL_GPL(nf_nat_sdp_addr_hook); | |
81 | ||
82 | unsigned int (*nf_nat_sdp_port_hook)(struct sk_buff *skb, unsigned int dataoff, | |
83 | const char **dptr, | |
84 | unsigned int *datalen, | |
85 | unsigned int matchoff, | |
86 | unsigned int matchlen, | |
87 | u_int16_t port) __read_mostly; | |
88 | EXPORT_SYMBOL_GPL(nf_nat_sdp_port_hook); | |
89 | ||
90 | unsigned int (*nf_nat_sdp_session_hook)(struct sk_buff *skb, | |
91 | unsigned int dataoff, | |
92 | const char **dptr, | |
93 | unsigned int *datalen, | |
94 | unsigned int sdpoff, | |
95 | const union nf_inet_addr *addr) | |
96 | __read_mostly; | |
97 | EXPORT_SYMBOL_GPL(nf_nat_sdp_session_hook); | |
98 | ||
99 | unsigned int (*nf_nat_sdp_media_hook)(struct sk_buff *skb, unsigned int dataoff, | |
100 | const char **dptr, | |
101 | unsigned int *datalen, | |
102 | struct nf_conntrack_expect *rtp_exp, | |
103 | struct nf_conntrack_expect *rtcp_exp, | |
104 | unsigned int mediaoff, | |
105 | unsigned int medialen, | |
106 | union nf_inet_addr *rtp_addr) | |
107 | __read_mostly; | |
108 | EXPORT_SYMBOL_GPL(nf_nat_sdp_media_hook); | |
109 | ||
110 | static int string_len(const struct nf_conn *ct, const char *dptr, | |
111 | const char *limit, int *shift) | |
112 | { | |
113 | int len = 0; | |
114 | ||
115 | while (dptr < limit && isalpha(*dptr)) { | |
116 | dptr++; | |
117 | len++; | |
118 | } | |
119 | return len; | |
120 | } | |
121 | ||
122 | static int digits_len(const struct nf_conn *ct, const char *dptr, | |
123 | const char *limit, int *shift) | |
124 | { | |
125 | int len = 0; | |
126 | while (dptr < limit && isdigit(*dptr)) { | |
127 | dptr++; | |
128 | len++; | |
129 | } | |
130 | return len; | |
131 | } | |
132 | ||
133 | static int iswordc(const char c) | |
134 | { | |
135 | if (isalnum(c) || c == '!' || c == '"' || c == '%' || | |
136 | (c >= '(' && c <= '/') || c == ':' || c == '<' || c == '>' || | |
137 | c == '?' || (c >= '[' && c <= ']') || c == '_' || c == '`' || | |
138 | c == '{' || c == '}' || c == '~') | |
139 | return 1; | |
140 | return 0; | |
141 | } | |
142 | ||
143 | static int word_len(const char *dptr, const char *limit) | |
144 | { | |
145 | int len = 0; | |
146 | while (dptr < limit && iswordc(*dptr)) { | |
147 | dptr++; | |
148 | len++; | |
149 | } | |
150 | return len; | |
151 | } | |
152 | ||
153 | static int callid_len(const struct nf_conn *ct, const char *dptr, | |
154 | const char *limit, int *shift) | |
155 | { | |
156 | int len, domain_len; | |
157 | ||
158 | len = word_len(dptr, limit); | |
159 | dptr += len; | |
160 | if (!len || dptr == limit || *dptr != '@') | |
161 | return len; | |
162 | dptr++; | |
163 | len++; | |
164 | ||
165 | domain_len = word_len(dptr, limit); | |
166 | if (!domain_len) | |
167 | return 0; | |
168 | return len + domain_len; | |
169 | } | |
170 | ||
171 | /* get media type + port length */ | |
172 | static int media_len(const struct nf_conn *ct, const char *dptr, | |
173 | const char *limit, int *shift) | |
174 | { | |
175 | int len = string_len(ct, dptr, limit, shift); | |
176 | ||
177 | dptr += len; | |
178 | if (dptr >= limit || *dptr != ' ') | |
179 | return 0; | |
180 | len++; | |
181 | dptr++; | |
182 | ||
183 | return len + digits_len(ct, dptr, limit, shift); | |
184 | } | |
185 | ||
186 | static int parse_addr(const struct nf_conn *ct, const char *cp, | |
187 | const char **endp, union nf_inet_addr *addr, | |
188 | const char *limit) | |
189 | { | |
190 | const char *end; | |
191 | int ret = 0; | |
192 | ||
193 | if (!ct) | |
194 | return 0; | |
195 | ||
196 | memset(addr, 0, sizeof(*addr)); | |
197 | switch (nf_ct_l3num(ct)) { | |
198 | case AF_INET: | |
199 | ret = in4_pton(cp, limit - cp, (u8 *)&addr->ip, -1, &end); | |
200 | break; | |
201 | case AF_INET6: | |
202 | ret = in6_pton(cp, limit - cp, (u8 *)&addr->ip6, -1, &end); | |
203 | break; | |
204 | default: | |
205 | BUG(); | |
206 | } | |
207 | ||
208 | if (ret == 0 || end == cp) | |
209 | return 0; | |
210 | if (endp) | |
211 | *endp = end; | |
212 | return 1; | |
213 | } | |
214 | ||
215 | /* skip ip address. returns its length. */ | |
216 | static int epaddr_len(const struct nf_conn *ct, const char *dptr, | |
217 | const char *limit, int *shift) | |
218 | { | |
219 | union nf_inet_addr addr; | |
220 | const char *aux = dptr; | |
221 | ||
222 | if (!parse_addr(ct, dptr, &dptr, &addr, limit)) { | |
223 | pr_debug("ip: %s parse failed.!\n", dptr); | |
224 | return 0; | |
225 | } | |
226 | ||
227 | /* Port number */ | |
228 | if (*dptr == ':') { | |
229 | dptr++; | |
230 | dptr += digits_len(ct, dptr, limit, shift); | |
231 | } | |
232 | return dptr - aux; | |
233 | } | |
234 | ||
235 | /* get address length, skiping user info. */ | |
236 | static int skp_epaddr_len(const struct nf_conn *ct, const char *dptr, | |
237 | const char *limit, int *shift) | |
238 | { | |
239 | const char *start = dptr; | |
240 | int s = *shift; | |
241 | ||
242 | /* Search for @, but stop at the end of the line. | |
243 | * We are inside a sip: URI, so we don't need to worry about | |
244 | * continuation lines. */ | |
245 | while (dptr < limit && | |
246 | *dptr != '@' && *dptr != '\r' && *dptr != '\n') { | |
247 | (*shift)++; | |
248 | dptr++; | |
249 | } | |
250 | ||
251 | if (dptr < limit && *dptr == '@') { | |
252 | dptr++; | |
253 | (*shift)++; | |
254 | } else { | |
255 | dptr = start; | |
256 | *shift = s; | |
257 | } | |
258 | ||
259 | return epaddr_len(ct, dptr, limit, shift); | |
260 | } | |
261 | ||
262 | /* Parse a SIP request line of the form: | |
263 | * | |
264 | * Request-Line = Method SP Request-URI SP SIP-Version CRLF | |
265 | * | |
266 | * and return the offset and length of the address contained in the Request-URI. | |
267 | */ | |
268 | int ct_sip_parse_request(const struct nf_conn *ct, | |
269 | const char *dptr, unsigned int datalen, | |
270 | unsigned int *matchoff, unsigned int *matchlen, | |
271 | union nf_inet_addr *addr, __be16 *port) | |
272 | { | |
273 | const char *start = dptr, *limit = dptr + datalen, *end; | |
274 | unsigned int mlen; | |
275 | unsigned int p; | |
276 | int shift = 0; | |
277 | ||
278 | /* Skip method and following whitespace */ | |
279 | mlen = string_len(ct, dptr, limit, NULL); | |
280 | if (!mlen) | |
281 | return 0; | |
282 | dptr += mlen; | |
283 | if (++dptr >= limit) | |
284 | return 0; | |
285 | ||
286 | /* Find SIP URI */ | |
287 | for (; dptr < limit - strlen("sip:"); dptr++) { | |
288 | if (*dptr == '\r' || *dptr == '\n') | |
289 | return -1; | |
290 | if (strnicmp(dptr, "sip:", strlen("sip:")) == 0) { | |
291 | dptr += strlen("sip:"); | |
292 | break; | |
293 | } | |
294 | } | |
295 | if (!skp_epaddr_len(ct, dptr, limit, &shift)) | |
296 | return 0; | |
297 | dptr += shift; | |
298 | ||
299 | if (!parse_addr(ct, dptr, &end, addr, limit)) | |
300 | return -1; | |
301 | if (end < limit && *end == ':') { | |
302 | end++; | |
303 | p = simple_strtoul(end, (char **)&end, 10); | |
304 | if (p < 1024 || p > 65535) | |
305 | return -1; | |
306 | *port = htons(p); | |
307 | } else | |
308 | *port = htons(SIP_PORT); | |
309 | ||
310 | if (end == dptr) | |
311 | return 0; | |
312 | *matchoff = dptr - start; | |
313 | *matchlen = end - dptr; | |
314 | return 1; | |
315 | } | |
316 | EXPORT_SYMBOL_GPL(ct_sip_parse_request); | |
317 | ||
318 | /* SIP header parsing: SIP headers are located at the beginning of a line, but | |
319 | * may span several lines, in which case the continuation lines begin with a | |
320 | * whitespace character. RFC 2543 allows lines to be terminated with CR, LF or | |
321 | * CRLF, RFC 3261 allows only CRLF, we support both. | |
322 | * | |
323 | * Headers are followed by (optionally) whitespace, a colon, again (optionally) | |
324 | * whitespace and the values. Whitespace in this context means any amount of | |
325 | * tabs, spaces and continuation lines, which are treated as a single whitespace | |
326 | * character. | |
327 | * | |
328 | * Some headers may appear multiple times. A comma separated list of values is | |
329 | * equivalent to multiple headers. | |
330 | */ | |
331 | static const struct sip_header ct_sip_hdrs[] = { | |
332 | [SIP_HDR_CSEQ] = SIP_HDR("CSeq", NULL, NULL, digits_len), | |
333 | [SIP_HDR_FROM] = SIP_HDR("From", "f", "sip:", skp_epaddr_len), | |
334 | [SIP_HDR_TO] = SIP_HDR("To", "t", "sip:", skp_epaddr_len), | |
335 | [SIP_HDR_CONTACT] = SIP_HDR("Contact", "m", "sip:", skp_epaddr_len), | |
336 | [SIP_HDR_VIA_UDP] = SIP_HDR("Via", "v", "UDP ", epaddr_len), | |
337 | [SIP_HDR_VIA_TCP] = SIP_HDR("Via", "v", "TCP ", epaddr_len), | |
338 | [SIP_HDR_EXPIRES] = SIP_HDR("Expires", NULL, NULL, digits_len), | |
339 | [SIP_HDR_CONTENT_LENGTH] = SIP_HDR("Content-Length", "l", NULL, digits_len), | |
340 | [SIP_HDR_CALL_ID] = SIP_HDR("Call-Id", "i", NULL, callid_len), | |
341 | }; | |
342 | ||
343 | static const char *sip_follow_continuation(const char *dptr, const char *limit) | |
344 | { | |
345 | /* Walk past newline */ | |
346 | if (++dptr >= limit) | |
347 | return NULL; | |
348 | ||
349 | /* Skip '\n' in CR LF */ | |
350 | if (*(dptr - 1) == '\r' && *dptr == '\n') { | |
351 | if (++dptr >= limit) | |
352 | return NULL; | |
353 | } | |
354 | ||
355 | /* Continuation line? */ | |
356 | if (*dptr != ' ' && *dptr != '\t') | |
357 | return NULL; | |
358 | ||
359 | /* skip leading whitespace */ | |
360 | for (; dptr < limit; dptr++) { | |
361 | if (*dptr != ' ' && *dptr != '\t') | |
362 | break; | |
363 | } | |
364 | return dptr; | |
365 | } | |
366 | ||
367 | static const char *sip_skip_whitespace(const char *dptr, const char *limit) | |
368 | { | |
369 | for (; dptr < limit; dptr++) { | |
370 | if (*dptr == ' ') | |
371 | continue; | |
372 | if (*dptr != '\r' && *dptr != '\n') | |
373 | break; | |
374 | dptr = sip_follow_continuation(dptr, limit); | |
375 | if (dptr == NULL) | |
376 | return NULL; | |
377 | } | |
378 | return dptr; | |
379 | } | |
380 | ||
381 | /* Search within a SIP header value, dealing with continuation lines */ | |
382 | static const char *ct_sip_header_search(const char *dptr, const char *limit, | |
383 | const char *needle, unsigned int len) | |
384 | { | |
385 | for (limit -= len; dptr < limit; dptr++) { | |
386 | if (*dptr == '\r' || *dptr == '\n') { | |
387 | dptr = sip_follow_continuation(dptr, limit); | |
388 | if (dptr == NULL) | |
389 | break; | |
390 | continue; | |
391 | } | |
392 | ||
393 | if (strnicmp(dptr, needle, len) == 0) | |
394 | return dptr; | |
395 | } | |
396 | return NULL; | |
397 | } | |
398 | ||
399 | int ct_sip_get_header(const struct nf_conn *ct, const char *dptr, | |
400 | unsigned int dataoff, unsigned int datalen, | |
401 | enum sip_header_types type, | |
402 | unsigned int *matchoff, unsigned int *matchlen) | |
403 | { | |
404 | const struct sip_header *hdr = &ct_sip_hdrs[type]; | |
405 | const char *start = dptr, *limit = dptr + datalen; | |
406 | int shift = 0; | |
407 | ||
408 | for (dptr += dataoff; dptr < limit; dptr++) { | |
409 | /* Find beginning of line */ | |
410 | if (*dptr != '\r' && *dptr != '\n') | |
411 | continue; | |
412 | if (++dptr >= limit) | |
413 | break; | |
414 | if (*(dptr - 1) == '\r' && *dptr == '\n') { | |
415 | if (++dptr >= limit) | |
416 | break; | |
417 | } | |
418 | ||
419 | /* Skip continuation lines */ | |
420 | if (*dptr == ' ' || *dptr == '\t') | |
421 | continue; | |
422 | ||
423 | /* Find header. Compact headers must be followed by a | |
424 | * non-alphabetic character to avoid mismatches. */ | |
425 | if (limit - dptr >= hdr->len && | |
426 | strnicmp(dptr, hdr->name, hdr->len) == 0) | |
427 | dptr += hdr->len; | |
428 | else if (hdr->cname && limit - dptr >= hdr->clen + 1 && | |
429 | strnicmp(dptr, hdr->cname, hdr->clen) == 0 && | |
430 | !isalpha(*(dptr + hdr->clen))) | |
431 | dptr += hdr->clen; | |
432 | else | |
433 | continue; | |
434 | ||
435 | /* Find and skip colon */ | |
436 | dptr = sip_skip_whitespace(dptr, limit); | |
437 | if (dptr == NULL) | |
438 | break; | |
439 | if (*dptr != ':' || ++dptr >= limit) | |
440 | break; | |
441 | ||
442 | /* Skip whitespace after colon */ | |
443 | dptr = sip_skip_whitespace(dptr, limit); | |
444 | if (dptr == NULL) | |
445 | break; | |
446 | ||
447 | *matchoff = dptr - start; | |
448 | if (hdr->search) { | |
449 | dptr = ct_sip_header_search(dptr, limit, hdr->search, | |
450 | hdr->slen); | |
451 | if (!dptr) | |
452 | return -1; | |
453 | dptr += hdr->slen; | |
454 | } | |
455 | ||
456 | *matchlen = hdr->match_len(ct, dptr, limit, &shift); | |
457 | if (!*matchlen) | |
458 | return -1; | |
459 | *matchoff = dptr - start + shift; | |
460 | return 1; | |
461 | } | |
462 | return 0; | |
463 | } | |
464 | EXPORT_SYMBOL_GPL(ct_sip_get_header); | |
465 | ||
466 | /* Get next header field in a list of comma separated values */ | |
467 | static int ct_sip_next_header(const struct nf_conn *ct, const char *dptr, | |
468 | unsigned int dataoff, unsigned int datalen, | |
469 | enum sip_header_types type, | |
470 | unsigned int *matchoff, unsigned int *matchlen) | |
471 | { | |
472 | const struct sip_header *hdr = &ct_sip_hdrs[type]; | |
473 | const char *start = dptr, *limit = dptr + datalen; | |
474 | int shift = 0; | |
475 | ||
476 | dptr += dataoff; | |
477 | ||
478 | dptr = ct_sip_header_search(dptr, limit, ",", strlen(",")); | |
479 | if (!dptr) | |
480 | return 0; | |
481 | ||
482 | dptr = ct_sip_header_search(dptr, limit, hdr->search, hdr->slen); | |
483 | if (!dptr) | |
484 | return 0; | |
485 | dptr += hdr->slen; | |
486 | ||
487 | *matchoff = dptr - start; | |
488 | *matchlen = hdr->match_len(ct, dptr, limit, &shift); | |
489 | if (!*matchlen) | |
490 | return -1; | |
491 | *matchoff += shift; | |
492 | return 1; | |
493 | } | |
494 | ||
495 | /* Walk through headers until a parsable one is found or no header of the | |
496 | * given type is left. */ | |
497 | static int ct_sip_walk_headers(const struct nf_conn *ct, const char *dptr, | |
498 | unsigned int dataoff, unsigned int datalen, | |
499 | enum sip_header_types type, int *in_header, | |
500 | unsigned int *matchoff, unsigned int *matchlen) | |
501 | { | |
502 | int ret; | |
503 | ||
504 | if (in_header && *in_header) { | |
505 | while (1) { | |
506 | ret = ct_sip_next_header(ct, dptr, dataoff, datalen, | |
507 | type, matchoff, matchlen); | |
508 | if (ret > 0) | |
509 | return ret; | |
510 | if (ret == 0) | |
511 | break; | |
512 | dataoff += *matchoff; | |
513 | } | |
514 | *in_header = 0; | |
515 | } | |
516 | ||
517 | while (1) { | |
518 | ret = ct_sip_get_header(ct, dptr, dataoff, datalen, | |
519 | type, matchoff, matchlen); | |
520 | if (ret > 0) | |
521 | break; | |
522 | if (ret == 0) | |
523 | return ret; | |
524 | dataoff += *matchoff; | |
525 | } | |
526 | ||
527 | if (in_header) | |
528 | *in_header = 1; | |
529 | return 1; | |
530 | } | |
531 | ||
532 | /* Locate a SIP header, parse the URI and return the offset and length of | |
533 | * the address as well as the address and port themselves. A stream of | |
534 | * headers can be parsed by handing in a non-NULL datalen and in_header | |
535 | * pointer. | |
536 | */ | |
537 | int ct_sip_parse_header_uri(const struct nf_conn *ct, const char *dptr, | |
538 | unsigned int *dataoff, unsigned int datalen, | |
539 | enum sip_header_types type, int *in_header, | |
540 | unsigned int *matchoff, unsigned int *matchlen, | |
541 | union nf_inet_addr *addr, __be16 *port) | |
542 | { | |
543 | const char *c, *limit = dptr + datalen; | |
544 | unsigned int p; | |
545 | int ret; | |
546 | ||
547 | ret = ct_sip_walk_headers(ct, dptr, dataoff ? *dataoff : 0, datalen, | |
548 | type, in_header, matchoff, matchlen); | |
549 | WARN_ON(ret < 0); | |
550 | if (ret == 0) | |
551 | return ret; | |
552 | ||
553 | if (!parse_addr(ct, dptr + *matchoff, &c, addr, limit)) | |
554 | return -1; | |
555 | if (*c == ':') { | |
556 | c++; | |
557 | p = simple_strtoul(c, (char **)&c, 10); | |
558 | if (p < 1024 || p > 65535) | |
559 | return -1; | |
560 | *port = htons(p); | |
561 | } else | |
562 | *port = htons(SIP_PORT); | |
563 | ||
564 | if (dataoff) | |
565 | *dataoff = c - dptr; | |
566 | return 1; | |
567 | } | |
568 | EXPORT_SYMBOL_GPL(ct_sip_parse_header_uri); | |
569 | ||
570 | static int ct_sip_parse_param(const struct nf_conn *ct, const char *dptr, | |
571 | unsigned int dataoff, unsigned int datalen, | |
572 | const char *name, | |
573 | unsigned int *matchoff, unsigned int *matchlen) | |
574 | { | |
575 | const char *limit = dptr + datalen; | |
576 | const char *start; | |
577 | const char *end; | |
578 | ||
579 | limit = ct_sip_header_search(dptr + dataoff, limit, ",", strlen(",")); | |
580 | if (!limit) | |
581 | limit = dptr + datalen; | |
582 | ||
583 | start = ct_sip_header_search(dptr + dataoff, limit, name, strlen(name)); | |
584 | if (!start) | |
585 | return 0; | |
586 | start += strlen(name); | |
587 | ||
588 | end = ct_sip_header_search(start, limit, ";", strlen(";")); | |
589 | if (!end) | |
590 | end = limit; | |
591 | ||
592 | *matchoff = start - dptr; | |
593 | *matchlen = end - start; | |
594 | return 1; | |
595 | } | |
596 | ||
597 | /* Parse address from header parameter and return address, offset and length */ | |
598 | int ct_sip_parse_address_param(const struct nf_conn *ct, const char *dptr, | |
599 | unsigned int dataoff, unsigned int datalen, | |
600 | const char *name, | |
601 | unsigned int *matchoff, unsigned int *matchlen, | |
602 | union nf_inet_addr *addr) | |
603 | { | |
604 | const char *limit = dptr + datalen; | |
605 | const char *start, *end; | |
606 | ||
607 | limit = ct_sip_header_search(dptr + dataoff, limit, ",", strlen(",")); | |
608 | if (!limit) | |
609 | limit = dptr + datalen; | |
610 | ||
611 | start = ct_sip_header_search(dptr + dataoff, limit, name, strlen(name)); | |
612 | if (!start) | |
613 | return 0; | |
614 | ||
615 | start += strlen(name); | |
616 | if (!parse_addr(ct, start, &end, addr, limit)) | |
617 | return 0; | |
618 | *matchoff = start - dptr; | |
619 | *matchlen = end - start; | |
620 | return 1; | |
621 | } | |
622 | EXPORT_SYMBOL_GPL(ct_sip_parse_address_param); | |
623 | ||
624 | /* Parse numerical header parameter and return value, offset and length */ | |
625 | int ct_sip_parse_numerical_param(const struct nf_conn *ct, const char *dptr, | |
626 | unsigned int dataoff, unsigned int datalen, | |
627 | const char *name, | |
628 | unsigned int *matchoff, unsigned int *matchlen, | |
629 | unsigned int *val) | |
630 | { | |
631 | const char *limit = dptr + datalen; | |
632 | const char *start; | |
633 | char *end; | |
634 | ||
635 | limit = ct_sip_header_search(dptr + dataoff, limit, ",", strlen(",")); | |
636 | if (!limit) | |
637 | limit = dptr + datalen; | |
638 | ||
639 | start = ct_sip_header_search(dptr + dataoff, limit, name, strlen(name)); | |
640 | if (!start) | |
641 | return 0; | |
642 | ||
643 | start += strlen(name); | |
644 | *val = simple_strtoul(start, &end, 0); | |
645 | if (start == end) | |
646 | return 0; | |
647 | if (matchoff && matchlen) { | |
648 | *matchoff = start - dptr; | |
649 | *matchlen = end - start; | |
650 | } | |
651 | return 1; | |
652 | } | |
653 | EXPORT_SYMBOL_GPL(ct_sip_parse_numerical_param); | |
654 | ||
655 | static int ct_sip_parse_transport(struct nf_conn *ct, const char *dptr, | |
656 | unsigned int dataoff, unsigned int datalen, | |
657 | u8 *proto) | |
658 | { | |
659 | unsigned int matchoff, matchlen; | |
660 | ||
661 | if (ct_sip_parse_param(ct, dptr, dataoff, datalen, "transport=", | |
662 | &matchoff, &matchlen)) { | |
663 | if (!strnicmp(dptr + matchoff, "TCP", strlen("TCP"))) | |
664 | *proto = IPPROTO_TCP; | |
665 | else if (!strnicmp(dptr + matchoff, "UDP", strlen("UDP"))) | |
666 | *proto = IPPROTO_UDP; | |
667 | else | |
668 | return 0; | |
669 | ||
670 | if (*proto != nf_ct_protonum(ct)) | |
671 | return 0; | |
672 | } else | |
673 | *proto = nf_ct_protonum(ct); | |
674 | ||
675 | return 1; | |
676 | } | |
677 | ||
678 | /* SDP header parsing: a SDP session description contains an ordered set of | |
679 | * headers, starting with a section containing general session parameters, | |
680 | * optionally followed by multiple media descriptions. | |
681 | * | |
682 | * SDP headers always start at the beginning of a line. According to RFC 2327: | |
683 | * "The sequence CRLF (0x0d0a) is used to end a record, although parsers should | |
684 | * be tolerant and also accept records terminated with a single newline | |
685 | * character". We handle both cases. | |
686 | */ | |
687 | static const struct sip_header ct_sdp_hdrs[] = { | |
688 | [SDP_HDR_VERSION] = SDP_HDR("v=", NULL, digits_len), | |
689 | [SDP_HDR_OWNER_IP4] = SDP_HDR("o=", "IN IP4 ", epaddr_len), | |
690 | [SDP_HDR_CONNECTION_IP4] = SDP_HDR("c=", "IN IP4 ", epaddr_len), | |
691 | [SDP_HDR_OWNER_IP6] = SDP_HDR("o=", "IN IP6 ", epaddr_len), | |
692 | [SDP_HDR_CONNECTION_IP6] = SDP_HDR("c=", "IN IP6 ", epaddr_len), | |
693 | [SDP_HDR_MEDIA] = SDP_HDR("m=", NULL, media_len), | |
694 | }; | |
695 | ||
696 | /* Linear string search within SDP header values */ | |
697 | static const char *ct_sdp_header_search(const char *dptr, const char *limit, | |
698 | const char *needle, unsigned int len) | |
699 | { | |
700 | for (limit -= len; dptr < limit; dptr++) { | |
701 | if (*dptr == '\r' || *dptr == '\n') | |
702 | break; | |
703 | if (strncmp(dptr, needle, len) == 0) | |
704 | return dptr; | |
705 | } | |
706 | return NULL; | |
707 | } | |
708 | ||
709 | /* Locate a SDP header (optionally a substring within the header value), | |
710 | * optionally stopping at the first occurrence of the term header, parse | |
711 | * it and return the offset and length of the data we're interested in. | |
712 | */ | |
713 | int ct_sip_get_sdp_header(const struct nf_conn *ct, const char *dptr, | |
714 | unsigned int dataoff, unsigned int datalen, | |
715 | enum sdp_header_types type, | |
716 | enum sdp_header_types term, | |
717 | unsigned int *matchoff, unsigned int *matchlen) | |
718 | { | |
719 | const struct sip_header *hdr = &ct_sdp_hdrs[type]; | |
720 | const struct sip_header *thdr = &ct_sdp_hdrs[term]; | |
721 | const char *start = dptr, *limit = dptr + datalen; | |
722 | int shift = 0; | |
723 | ||
724 | for (dptr += dataoff; dptr < limit; dptr++) { | |
725 | /* Find beginning of line */ | |
726 | if (*dptr != '\r' && *dptr != '\n') | |
727 | continue; | |
728 | if (++dptr >= limit) | |
729 | break; | |
730 | if (*(dptr - 1) == '\r' && *dptr == '\n') { | |
731 | if (++dptr >= limit) | |
732 | break; | |
733 | } | |
734 | ||
735 | if (term != SDP_HDR_UNSPEC && | |
736 | limit - dptr >= thdr->len && | |
737 | strnicmp(dptr, thdr->name, thdr->len) == 0) | |
738 | break; | |
739 | else if (limit - dptr >= hdr->len && | |
740 | strnicmp(dptr, hdr->name, hdr->len) == 0) | |
741 | dptr += hdr->len; | |
742 | else | |
743 | continue; | |
744 | ||
745 | *matchoff = dptr - start; | |
746 | if (hdr->search) { | |
747 | dptr = ct_sdp_header_search(dptr, limit, hdr->search, | |
748 | hdr->slen); | |
749 | if (!dptr) | |
750 | return -1; | |
751 | dptr += hdr->slen; | |
752 | } | |
753 | ||
754 | *matchlen = hdr->match_len(ct, dptr, limit, &shift); | |
755 | if (!*matchlen) | |
756 | return -1; | |
757 | *matchoff = dptr - start + shift; | |
758 | return 1; | |
759 | } | |
760 | return 0; | |
761 | } | |
762 | EXPORT_SYMBOL_GPL(ct_sip_get_sdp_header); | |
763 | ||
764 | static int ct_sip_parse_sdp_addr(const struct nf_conn *ct, const char *dptr, | |
765 | unsigned int dataoff, unsigned int datalen, | |
766 | enum sdp_header_types type, | |
767 | enum sdp_header_types term, | |
768 | unsigned int *matchoff, unsigned int *matchlen, | |
769 | union nf_inet_addr *addr) | |
770 | { | |
771 | int ret; | |
772 | ||
773 | ret = ct_sip_get_sdp_header(ct, dptr, dataoff, datalen, type, term, | |
774 | matchoff, matchlen); | |
775 | if (ret <= 0) | |
776 | return ret; | |
777 | ||
778 | if (!parse_addr(ct, dptr + *matchoff, NULL, addr, | |
779 | dptr + *matchoff + *matchlen)) | |
780 | return -1; | |
781 | return 1; | |
782 | } | |
783 | ||
784 | static int refresh_signalling_expectation(struct nf_conn *ct, | |
785 | union nf_inet_addr *addr, | |
786 | u8 proto, __be16 port, | |
787 | unsigned int expires) | |
788 | { | |
789 | struct nf_conn_help *help = nfct_help(ct); | |
790 | struct nf_conntrack_expect *exp; | |
791 | struct hlist_node *n, *next; | |
792 | int found = 0; | |
793 | ||
794 | spin_lock_bh(&nf_conntrack_lock); | |
795 | hlist_for_each_entry_safe(exp, n, next, &help->expectations, lnode) { | |
796 | if (exp->class != SIP_EXPECT_SIGNALLING || | |
797 | !nf_inet_addr_cmp(&exp->tuple.dst.u3, addr) || | |
798 | exp->tuple.dst.protonum != proto || | |
799 | exp->tuple.dst.u.udp.port != port) | |
800 | continue; | |
801 | if (!del_timer(&exp->timeout)) | |
802 | continue; | |
803 | exp->flags &= ~NF_CT_EXPECT_INACTIVE; | |
804 | exp->timeout.expires = jiffies + expires * HZ; | |
805 | add_timer(&exp->timeout); | |
806 | found = 1; | |
807 | break; | |
808 | } | |
809 | spin_unlock_bh(&nf_conntrack_lock); | |
810 | return found; | |
811 | } | |
812 | ||
813 | static void flush_expectations(struct nf_conn *ct, bool media) | |
814 | { | |
815 | struct nf_conn_help *help = nfct_help(ct); | |
816 | struct nf_conntrack_expect *exp; | |
817 | struct hlist_node *n, *next; | |
818 | ||
819 | spin_lock_bh(&nf_conntrack_lock); | |
820 | hlist_for_each_entry_safe(exp, n, next, &help->expectations, lnode) { | |
821 | if ((exp->class != SIP_EXPECT_SIGNALLING) ^ media) | |
822 | continue; | |
823 | if (!del_timer(&exp->timeout)) | |
824 | continue; | |
825 | nf_ct_unlink_expect(exp); | |
826 | nf_ct_expect_put(exp); | |
827 | if (!media) | |
828 | break; | |
829 | } | |
830 | spin_unlock_bh(&nf_conntrack_lock); | |
831 | } | |
832 | ||
833 | static int set_expected_rtp_rtcp(struct sk_buff *skb, unsigned int dataoff, | |
834 | const char **dptr, unsigned int *datalen, | |
835 | union nf_inet_addr *daddr, __be16 port, | |
836 | enum sip_expectation_classes class, | |
837 | unsigned int mediaoff, unsigned int medialen) | |
838 | { | |
839 | struct nf_conntrack_expect *exp, *rtp_exp, *rtcp_exp; | |
840 | enum ip_conntrack_info ctinfo; | |
841 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
842 | struct net *net = nf_ct_net(ct); | |
843 | enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); | |
844 | union nf_inet_addr *saddr; | |
845 | struct nf_conntrack_tuple tuple; | |
846 | int direct_rtp = 0, skip_expect = 0, ret = NF_DROP; | |
847 | u_int16_t base_port; | |
848 | __be16 rtp_port, rtcp_port; | |
849 | typeof(nf_nat_sdp_port_hook) nf_nat_sdp_port; | |
850 | typeof(nf_nat_sdp_media_hook) nf_nat_sdp_media; | |
851 | ||
852 | saddr = NULL; | |
853 | if (sip_direct_media) { | |
854 | if (!nf_inet_addr_cmp(daddr, &ct->tuplehash[dir].tuple.src.u3)) | |
855 | return NF_ACCEPT; | |
856 | saddr = &ct->tuplehash[!dir].tuple.src.u3; | |
857 | } | |
858 | ||
859 | /* We need to check whether the registration exists before attempting | |
860 | * to register it since we can see the same media description multiple | |
861 | * times on different connections in case multiple endpoints receive | |
862 | * the same call. | |
863 | * | |
864 | * RTP optimization: if we find a matching media channel expectation | |
865 | * and both the expectation and this connection are SNATed, we assume | |
866 | * both sides can reach each other directly and use the final | |
867 | * destination address from the expectation. We still need to keep | |
868 | * the NATed expectations for media that might arrive from the | |
869 | * outside, and additionally need to expect the direct RTP stream | |
870 | * in case it passes through us even without NAT. | |
871 | */ | |
872 | memset(&tuple, 0, sizeof(tuple)); | |
873 | if (saddr) | |
874 | tuple.src.u3 = *saddr; | |
875 | tuple.src.l3num = nf_ct_l3num(ct); | |
876 | tuple.dst.protonum = IPPROTO_UDP; | |
877 | tuple.dst.u3 = *daddr; | |
878 | tuple.dst.u.udp.port = port; | |
879 | ||
880 | rcu_read_lock(); | |
881 | do { | |
882 | exp = __nf_ct_expect_find(net, nf_ct_zone(ct), &tuple); | |
883 | ||
884 | if (!exp || exp->master == ct || | |
885 | nfct_help(exp->master)->helper != nfct_help(ct)->helper || | |
886 | exp->class != class) | |
887 | break; | |
888 | #ifdef CONFIG_NF_NAT_NEEDED | |
889 | if (exp->tuple.src.l3num == AF_INET && !direct_rtp && | |
890 | (exp->saved_ip != exp->tuple.dst.u3.ip || | |
891 | exp->saved_proto.udp.port != exp->tuple.dst.u.udp.port) && | |
892 | ct->status & IPS_NAT_MASK) { | |
893 | daddr->ip = exp->saved_ip; | |
894 | tuple.dst.u3.ip = exp->saved_ip; | |
895 | tuple.dst.u.udp.port = exp->saved_proto.udp.port; | |
896 | direct_rtp = 1; | |
897 | } else | |
898 | #endif | |
899 | skip_expect = 1; | |
900 | } while (!skip_expect); | |
901 | rcu_read_unlock(); | |
902 | ||
903 | base_port = ntohs(tuple.dst.u.udp.port) & ~1; | |
904 | rtp_port = htons(base_port); | |
905 | rtcp_port = htons(base_port + 1); | |
906 | ||
907 | if (direct_rtp) { | |
908 | nf_nat_sdp_port = rcu_dereference(nf_nat_sdp_port_hook); | |
909 | if (nf_nat_sdp_port && | |
910 | !nf_nat_sdp_port(skb, dataoff, dptr, datalen, | |
911 | mediaoff, medialen, ntohs(rtp_port))) | |
912 | goto err1; | |
913 | } | |
914 | ||
915 | if (skip_expect) | |
916 | return NF_ACCEPT; | |
917 | ||
918 | rtp_exp = nf_ct_expect_alloc(ct); | |
919 | if (rtp_exp == NULL) | |
920 | goto err1; | |
921 | nf_ct_expect_init(rtp_exp, class, nf_ct_l3num(ct), saddr, daddr, | |
922 | IPPROTO_UDP, NULL, &rtp_port); | |
923 | ||
924 | rtcp_exp = nf_ct_expect_alloc(ct); | |
925 | if (rtcp_exp == NULL) | |
926 | goto err2; | |
927 | nf_ct_expect_init(rtcp_exp, class, nf_ct_l3num(ct), saddr, daddr, | |
928 | IPPROTO_UDP, NULL, &rtcp_port); | |
929 | ||
930 | nf_nat_sdp_media = rcu_dereference(nf_nat_sdp_media_hook); | |
931 | if (nf_nat_sdp_media && ct->status & IPS_NAT_MASK && !direct_rtp) | |
932 | ret = nf_nat_sdp_media(skb, dataoff, dptr, datalen, | |
933 | rtp_exp, rtcp_exp, | |
934 | mediaoff, medialen, daddr); | |
935 | else { | |
936 | if (nf_ct_expect_related(rtp_exp) == 0) { | |
937 | if (nf_ct_expect_related(rtcp_exp) != 0) | |
938 | nf_ct_unexpect_related(rtp_exp); | |
939 | else | |
940 | ret = NF_ACCEPT; | |
941 | } | |
942 | } | |
943 | nf_ct_expect_put(rtcp_exp); | |
944 | err2: | |
945 | nf_ct_expect_put(rtp_exp); | |
946 | err1: | |
947 | return ret; | |
948 | } | |
949 | ||
950 | static const struct sdp_media_type sdp_media_types[] = { | |
951 | SDP_MEDIA_TYPE("audio ", SIP_EXPECT_AUDIO), | |
952 | SDP_MEDIA_TYPE("video ", SIP_EXPECT_VIDEO), | |
953 | SDP_MEDIA_TYPE("image ", SIP_EXPECT_IMAGE), | |
954 | }; | |
955 | ||
956 | static const struct sdp_media_type *sdp_media_type(const char *dptr, | |
957 | unsigned int matchoff, | |
958 | unsigned int matchlen) | |
959 | { | |
960 | const struct sdp_media_type *t; | |
961 | unsigned int i; | |
962 | ||
963 | for (i = 0; i < ARRAY_SIZE(sdp_media_types); i++) { | |
964 | t = &sdp_media_types[i]; | |
965 | if (matchlen < t->len || | |
966 | strncmp(dptr + matchoff, t->name, t->len)) | |
967 | continue; | |
968 | return t; | |
969 | } | |
970 | return NULL; | |
971 | } | |
972 | ||
973 | static int process_sdp(struct sk_buff *skb, unsigned int dataoff, | |
974 | const char **dptr, unsigned int *datalen, | |
975 | unsigned int cseq) | |
976 | { | |
977 | enum ip_conntrack_info ctinfo; | |
978 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
979 | unsigned int matchoff, matchlen; | |
980 | unsigned int mediaoff, medialen; | |
981 | unsigned int sdpoff; | |
982 | unsigned int caddr_len, maddr_len; | |
983 | unsigned int i; | |
984 | union nf_inet_addr caddr, maddr, rtp_addr; | |
985 | unsigned int port; | |
986 | enum sdp_header_types c_hdr; | |
987 | const struct sdp_media_type *t; | |
988 | int ret = NF_ACCEPT; | |
989 | typeof(nf_nat_sdp_addr_hook) nf_nat_sdp_addr; | |
990 | typeof(nf_nat_sdp_session_hook) nf_nat_sdp_session; | |
991 | ||
992 | nf_nat_sdp_addr = rcu_dereference(nf_nat_sdp_addr_hook); | |
993 | c_hdr = nf_ct_l3num(ct) == AF_INET ? SDP_HDR_CONNECTION_IP4 : | |
994 | SDP_HDR_CONNECTION_IP6; | |
995 | ||
996 | /* Find beginning of session description */ | |
997 | if (ct_sip_get_sdp_header(ct, *dptr, 0, *datalen, | |
998 | SDP_HDR_VERSION, SDP_HDR_UNSPEC, | |
999 | &matchoff, &matchlen) <= 0) | |
1000 | return NF_ACCEPT; | |
1001 | sdpoff = matchoff; | |
1002 | ||
1003 | /* The connection information is contained in the session description | |
1004 | * and/or once per media description. The first media description marks | |
1005 | * the end of the session description. */ | |
1006 | caddr_len = 0; | |
1007 | if (ct_sip_parse_sdp_addr(ct, *dptr, sdpoff, *datalen, | |
1008 | c_hdr, SDP_HDR_MEDIA, | |
1009 | &matchoff, &matchlen, &caddr) > 0) | |
1010 | caddr_len = matchlen; | |
1011 | ||
1012 | mediaoff = sdpoff; | |
1013 | for (i = 0; i < ARRAY_SIZE(sdp_media_types); ) { | |
1014 | if (ct_sip_get_sdp_header(ct, *dptr, mediaoff, *datalen, | |
1015 | SDP_HDR_MEDIA, SDP_HDR_UNSPEC, | |
1016 | &mediaoff, &medialen) <= 0) | |
1017 | break; | |
1018 | ||
1019 | /* Get media type and port number. A media port value of zero | |
1020 | * indicates an inactive stream. */ | |
1021 | t = sdp_media_type(*dptr, mediaoff, medialen); | |
1022 | if (!t) { | |
1023 | mediaoff += medialen; | |
1024 | continue; | |
1025 | } | |
1026 | mediaoff += t->len; | |
1027 | medialen -= t->len; | |
1028 | ||
1029 | port = simple_strtoul(*dptr + mediaoff, NULL, 10); | |
1030 | if (port == 0) | |
1031 | continue; | |
1032 | if (port < 1024 || port > 65535) | |
1033 | return NF_DROP; | |
1034 | ||
1035 | /* The media description overrides the session description. */ | |
1036 | maddr_len = 0; | |
1037 | if (ct_sip_parse_sdp_addr(ct, *dptr, mediaoff, *datalen, | |
1038 | c_hdr, SDP_HDR_MEDIA, | |
1039 | &matchoff, &matchlen, &maddr) > 0) { | |
1040 | maddr_len = matchlen; | |
1041 | memcpy(&rtp_addr, &maddr, sizeof(rtp_addr)); | |
1042 | } else if (caddr_len) | |
1043 | memcpy(&rtp_addr, &caddr, sizeof(rtp_addr)); | |
1044 | else | |
1045 | return NF_DROP; | |
1046 | ||
1047 | ret = set_expected_rtp_rtcp(skb, dataoff, dptr, datalen, | |
1048 | &rtp_addr, htons(port), t->class, | |
1049 | mediaoff, medialen); | |
1050 | if (ret != NF_ACCEPT) | |
1051 | return ret; | |
1052 | ||
1053 | /* Update media connection address if present */ | |
1054 | if (maddr_len && nf_nat_sdp_addr && ct->status & IPS_NAT_MASK) { | |
1055 | ret = nf_nat_sdp_addr(skb, dataoff, dptr, datalen, | |
1056 | mediaoff, c_hdr, SDP_HDR_MEDIA, | |
1057 | &rtp_addr); | |
1058 | if (ret != NF_ACCEPT) | |
1059 | return ret; | |
1060 | } | |
1061 | i++; | |
1062 | } | |
1063 | ||
1064 | /* Update session connection and owner addresses */ | |
1065 | nf_nat_sdp_session = rcu_dereference(nf_nat_sdp_session_hook); | |
1066 | if (nf_nat_sdp_session && ct->status & IPS_NAT_MASK) | |
1067 | ret = nf_nat_sdp_session(skb, dataoff, dptr, datalen, sdpoff, | |
1068 | &rtp_addr); | |
1069 | ||
1070 | return ret; | |
1071 | } | |
1072 | static int process_invite_response(struct sk_buff *skb, unsigned int dataoff, | |
1073 | const char **dptr, unsigned int *datalen, | |
1074 | unsigned int cseq, unsigned int code) | |
1075 | { | |
1076 | enum ip_conntrack_info ctinfo; | |
1077 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
1078 | struct nf_conn_help *help = nfct_help(ct); | |
1079 | ||
1080 | if ((code >= 100 && code <= 199) || | |
1081 | (code >= 200 && code <= 299)) | |
1082 | return process_sdp(skb, dataoff, dptr, datalen, cseq); | |
1083 | else if (help->help.ct_sip_info.invite_cseq == cseq) | |
1084 | flush_expectations(ct, true); | |
1085 | return NF_ACCEPT; | |
1086 | } | |
1087 | ||
1088 | static int process_update_response(struct sk_buff *skb, unsigned int dataoff, | |
1089 | const char **dptr, unsigned int *datalen, | |
1090 | unsigned int cseq, unsigned int code) | |
1091 | { | |
1092 | enum ip_conntrack_info ctinfo; | |
1093 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
1094 | struct nf_conn_help *help = nfct_help(ct); | |
1095 | ||
1096 | if ((code >= 100 && code <= 199) || | |
1097 | (code >= 200 && code <= 299)) | |
1098 | return process_sdp(skb, dataoff, dptr, datalen, cseq); | |
1099 | else if (help->help.ct_sip_info.invite_cseq == cseq) | |
1100 | flush_expectations(ct, true); | |
1101 | return NF_ACCEPT; | |
1102 | } | |
1103 | ||
1104 | static int process_prack_response(struct sk_buff *skb, unsigned int dataoff, | |
1105 | const char **dptr, unsigned int *datalen, | |
1106 | unsigned int cseq, unsigned int code) | |
1107 | { | |
1108 | enum ip_conntrack_info ctinfo; | |
1109 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
1110 | struct nf_conn_help *help = nfct_help(ct); | |
1111 | ||
1112 | if ((code >= 100 && code <= 199) || | |
1113 | (code >= 200 && code <= 299)) | |
1114 | return process_sdp(skb, dataoff, dptr, datalen, cseq); | |
1115 | else if (help->help.ct_sip_info.invite_cseq == cseq) | |
1116 | flush_expectations(ct, true); | |
1117 | return NF_ACCEPT; | |
1118 | } | |
1119 | ||
1120 | static int process_invite_request(struct sk_buff *skb, unsigned int dataoff, | |
1121 | const char **dptr, unsigned int *datalen, | |
1122 | unsigned int cseq) | |
1123 | { | |
1124 | enum ip_conntrack_info ctinfo; | |
1125 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
1126 | struct nf_conn_help *help = nfct_help(ct); | |
1127 | unsigned int ret; | |
1128 | ||
1129 | flush_expectations(ct, true); | |
1130 | ret = process_sdp(skb, dataoff, dptr, datalen, cseq); | |
1131 | if (ret == NF_ACCEPT) | |
1132 | help->help.ct_sip_info.invite_cseq = cseq; | |
1133 | return ret; | |
1134 | } | |
1135 | ||
1136 | static int process_bye_request(struct sk_buff *skb, unsigned int dataoff, | |
1137 | const char **dptr, unsigned int *datalen, | |
1138 | unsigned int cseq) | |
1139 | { | |
1140 | enum ip_conntrack_info ctinfo; | |
1141 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
1142 | ||
1143 | flush_expectations(ct, true); | |
1144 | return NF_ACCEPT; | |
1145 | } | |
1146 | ||
1147 | /* Parse a REGISTER request and create a permanent expectation for incoming | |
1148 | * signalling connections. The expectation is marked inactive and is activated | |
1149 | * when receiving a response indicating success from the registrar. | |
1150 | */ | |
1151 | static int process_register_request(struct sk_buff *skb, unsigned int dataoff, | |
1152 | const char **dptr, unsigned int *datalen, | |
1153 | unsigned int cseq) | |
1154 | { | |
1155 | enum ip_conntrack_info ctinfo; | |
1156 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
1157 | struct nf_conn_help *help = nfct_help(ct); | |
1158 | enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); | |
1159 | unsigned int matchoff, matchlen; | |
1160 | struct nf_conntrack_expect *exp; | |
1161 | union nf_inet_addr *saddr, daddr; | |
1162 | __be16 port; | |
1163 | u8 proto; | |
1164 | unsigned int expires = 0; | |
1165 | int ret; | |
1166 | typeof(nf_nat_sip_expect_hook) nf_nat_sip_expect; | |
1167 | ||
1168 | /* Expected connections can not register again. */ | |
1169 | if (ct->status & IPS_EXPECTED) | |
1170 | return NF_ACCEPT; | |
1171 | ||
1172 | /* We must check the expiration time: a value of zero signals the | |
1173 | * registrar to release the binding. We'll remove our expectation | |
1174 | * when receiving the new bindings in the response, but we don't | |
1175 | * want to create new ones. | |
1176 | * | |
1177 | * The expiration time may be contained in Expires: header, the | |
1178 | * Contact: header parameters or the URI parameters. | |
1179 | */ | |
1180 | if (ct_sip_get_header(ct, *dptr, 0, *datalen, SIP_HDR_EXPIRES, | |
1181 | &matchoff, &matchlen) > 0) | |
1182 | expires = simple_strtoul(*dptr + matchoff, NULL, 10); | |
1183 | ||
1184 | ret = ct_sip_parse_header_uri(ct, *dptr, NULL, *datalen, | |
1185 | SIP_HDR_CONTACT, NULL, | |
1186 | &matchoff, &matchlen, &daddr, &port); | |
1187 | if (ret < 0) | |
1188 | return NF_DROP; | |
1189 | else if (ret == 0) | |
1190 | return NF_ACCEPT; | |
1191 | ||
1192 | /* We don't support third-party registrations */ | |
1193 | if (!nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.src.u3, &daddr)) | |
1194 | return NF_ACCEPT; | |
1195 | ||
1196 | if (ct_sip_parse_transport(ct, *dptr, matchoff + matchlen, *datalen, | |
1197 | &proto) == 0) | |
1198 | return NF_ACCEPT; | |
1199 | ||
1200 | if (ct_sip_parse_numerical_param(ct, *dptr, | |
1201 | matchoff + matchlen, *datalen, | |
1202 | "expires=", NULL, NULL, &expires) < 0) | |
1203 | return NF_DROP; | |
1204 | ||
1205 | if (expires == 0) { | |
1206 | ret = NF_ACCEPT; | |
1207 | goto store_cseq; | |
1208 | } | |
1209 | ||
1210 | exp = nf_ct_expect_alloc(ct); | |
1211 | if (!exp) | |
1212 | return NF_DROP; | |
1213 | ||
1214 | saddr = NULL; | |
1215 | if (sip_direct_signalling) | |
1216 | saddr = &ct->tuplehash[!dir].tuple.src.u3; | |
1217 | ||
1218 | nf_ct_expect_init(exp, SIP_EXPECT_SIGNALLING, nf_ct_l3num(ct), | |
1219 | saddr, &daddr, proto, NULL, &port); | |
1220 | exp->timeout.expires = sip_timeout * HZ; | |
1221 | exp->helper = nfct_help(ct)->helper; | |
1222 | exp->flags = NF_CT_EXPECT_PERMANENT | NF_CT_EXPECT_INACTIVE; | |
1223 | ||
1224 | nf_nat_sip_expect = rcu_dereference(nf_nat_sip_expect_hook); | |
1225 | if (nf_nat_sip_expect && ct->status & IPS_NAT_MASK) | |
1226 | ret = nf_nat_sip_expect(skb, dataoff, dptr, datalen, exp, | |
1227 | matchoff, matchlen); | |
1228 | else { | |
1229 | if (nf_ct_expect_related(exp) != 0) | |
1230 | ret = NF_DROP; | |
1231 | else | |
1232 | ret = NF_ACCEPT; | |
1233 | } | |
1234 | nf_ct_expect_put(exp); | |
1235 | ||
1236 | store_cseq: | |
1237 | if (ret == NF_ACCEPT) | |
1238 | help->help.ct_sip_info.register_cseq = cseq; | |
1239 | return ret; | |
1240 | } | |
1241 | ||
1242 | static int process_register_response(struct sk_buff *skb, unsigned int dataoff, | |
1243 | const char **dptr, unsigned int *datalen, | |
1244 | unsigned int cseq, unsigned int code) | |
1245 | { | |
1246 | enum ip_conntrack_info ctinfo; | |
1247 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
1248 | struct nf_conn_help *help = nfct_help(ct); | |
1249 | enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); | |
1250 | union nf_inet_addr addr; | |
1251 | __be16 port; | |
1252 | u8 proto; | |
1253 | unsigned int matchoff, matchlen, coff = 0; | |
1254 | unsigned int expires = 0; | |
1255 | int in_contact = 0, ret; | |
1256 | ||
1257 | /* According to RFC 3261, "UAs MUST NOT send a new registration until | |
1258 | * they have received a final response from the registrar for the | |
1259 | * previous one or the previous REGISTER request has timed out". | |
1260 | * | |
1261 | * However, some servers fail to detect retransmissions and send late | |
1262 | * responses, so we store the sequence number of the last valid | |
1263 | * request and compare it here. | |
1264 | */ | |
1265 | if (help->help.ct_sip_info.register_cseq != cseq) | |
1266 | return NF_ACCEPT; | |
1267 | ||
1268 | if (code >= 100 && code <= 199) | |
1269 | return NF_ACCEPT; | |
1270 | if (code < 200 || code > 299) | |
1271 | goto flush; | |
1272 | ||
1273 | if (ct_sip_get_header(ct, *dptr, 0, *datalen, SIP_HDR_EXPIRES, | |
1274 | &matchoff, &matchlen) > 0) | |
1275 | expires = simple_strtoul(*dptr + matchoff, NULL, 10); | |
1276 | ||
1277 | while (1) { | |
1278 | unsigned int c_expires = expires; | |
1279 | ||
1280 | ret = ct_sip_parse_header_uri(ct, *dptr, &coff, *datalen, | |
1281 | SIP_HDR_CONTACT, &in_contact, | |
1282 | &matchoff, &matchlen, | |
1283 | &addr, &port); | |
1284 | if (ret < 0) | |
1285 | return NF_DROP; | |
1286 | else if (ret == 0) | |
1287 | break; | |
1288 | ||
1289 | /* We don't support third-party registrations */ | |
1290 | if (!nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.dst.u3, &addr)) | |
1291 | continue; | |
1292 | ||
1293 | if (ct_sip_parse_transport(ct, *dptr, matchoff + matchlen, | |
1294 | *datalen, &proto) == 0) | |
1295 | continue; | |
1296 | ||
1297 | ret = ct_sip_parse_numerical_param(ct, *dptr, | |
1298 | matchoff + matchlen, | |
1299 | *datalen, "expires=", | |
1300 | NULL, NULL, &c_expires); | |
1301 | if (ret < 0) | |
1302 | return NF_DROP; | |
1303 | if (c_expires == 0) | |
1304 | break; | |
1305 | if (refresh_signalling_expectation(ct, &addr, proto, port, | |
1306 | c_expires)) | |
1307 | return NF_ACCEPT; | |
1308 | } | |
1309 | ||
1310 | flush: | |
1311 | flush_expectations(ct, false); | |
1312 | return NF_ACCEPT; | |
1313 | } | |
1314 | ||
1315 | static const struct sip_handler sip_handlers[] = { | |
1316 | SIP_HANDLER("INVITE", process_invite_request, process_invite_response), | |
1317 | SIP_HANDLER("UPDATE", process_sdp, process_update_response), | |
1318 | SIP_HANDLER("ACK", process_sdp, NULL), | |
1319 | SIP_HANDLER("PRACK", process_sdp, process_prack_response), | |
1320 | SIP_HANDLER("BYE", process_bye_request, NULL), | |
1321 | SIP_HANDLER("REGISTER", process_register_request, process_register_response), | |
1322 | }; | |
1323 | ||
1324 | static int process_sip_response(struct sk_buff *skb, unsigned int dataoff, | |
1325 | const char **dptr, unsigned int *datalen) | |
1326 | { | |
1327 | enum ip_conntrack_info ctinfo; | |
1328 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
1329 | unsigned int matchoff, matchlen, matchend; | |
1330 | unsigned int code, cseq, i; | |
1331 | ||
1332 | if (*datalen < strlen("SIP/2.0 200")) | |
1333 | return NF_ACCEPT; | |
1334 | code = simple_strtoul(*dptr + strlen("SIP/2.0 "), NULL, 10); | |
1335 | if (!code) | |
1336 | return NF_DROP; | |
1337 | ||
1338 | if (ct_sip_get_header(ct, *dptr, 0, *datalen, SIP_HDR_CSEQ, | |
1339 | &matchoff, &matchlen) <= 0) | |
1340 | return NF_DROP; | |
1341 | cseq = simple_strtoul(*dptr + matchoff, NULL, 10); | |
1342 | if (!cseq) | |
1343 | return NF_DROP; | |
1344 | matchend = matchoff + matchlen + 1; | |
1345 | ||
1346 | for (i = 0; i < ARRAY_SIZE(sip_handlers); i++) { | |
1347 | const struct sip_handler *handler; | |
1348 | ||
1349 | handler = &sip_handlers[i]; | |
1350 | if (handler->response == NULL) | |
1351 | continue; | |
1352 | if (*datalen < matchend + handler->len || | |
1353 | strnicmp(*dptr + matchend, handler->method, handler->len)) | |
1354 | continue; | |
1355 | return handler->response(skb, dataoff, dptr, datalen, | |
1356 | cseq, code); | |
1357 | } | |
1358 | return NF_ACCEPT; | |
1359 | } | |
1360 | ||
1361 | static int process_sip_request(struct sk_buff *skb, unsigned int dataoff, | |
1362 | const char **dptr, unsigned int *datalen) | |
1363 | { | |
1364 | enum ip_conntrack_info ctinfo; | |
1365 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
1366 | unsigned int matchoff, matchlen; | |
1367 | unsigned int cseq, i; | |
1368 | ||
1369 | for (i = 0; i < ARRAY_SIZE(sip_handlers); i++) { | |
1370 | const struct sip_handler *handler; | |
1371 | ||
1372 | handler = &sip_handlers[i]; | |
1373 | if (handler->request == NULL) | |
1374 | continue; | |
1375 | if (*datalen < handler->len || | |
1376 | strnicmp(*dptr, handler->method, handler->len)) | |
1377 | continue; | |
1378 | ||
1379 | if (ct_sip_get_header(ct, *dptr, 0, *datalen, SIP_HDR_CSEQ, | |
1380 | &matchoff, &matchlen) <= 0) | |
1381 | return NF_DROP; | |
1382 | cseq = simple_strtoul(*dptr + matchoff, NULL, 10); | |
1383 | if (!cseq) | |
1384 | return NF_DROP; | |
1385 | ||
1386 | return handler->request(skb, dataoff, dptr, datalen, cseq); | |
1387 | } | |
1388 | return NF_ACCEPT; | |
1389 | } | |
1390 | ||
1391 | static int process_sip_msg(struct sk_buff *skb, struct nf_conn *ct, | |
1392 | unsigned int dataoff, const char **dptr, | |
1393 | unsigned int *datalen) | |
1394 | { | |
1395 | typeof(nf_nat_sip_hook) nf_nat_sip; | |
1396 | int ret; | |
1397 | ||
1398 | if (strnicmp(*dptr, "SIP/2.0 ", strlen("SIP/2.0 ")) != 0) | |
1399 | ret = process_sip_request(skb, dataoff, dptr, datalen); | |
1400 | else | |
1401 | ret = process_sip_response(skb, dataoff, dptr, datalen); | |
1402 | ||
1403 | if (ret == NF_ACCEPT && ct->status & IPS_NAT_MASK) { | |
1404 | nf_nat_sip = rcu_dereference(nf_nat_sip_hook); | |
1405 | if (nf_nat_sip && !nf_nat_sip(skb, dataoff, dptr, datalen)) | |
1406 | ret = NF_DROP; | |
1407 | } | |
1408 | ||
1409 | return ret; | |
1410 | } | |
1411 | ||
1412 | static int sip_help_tcp(struct sk_buff *skb, unsigned int protoff, | |
1413 | struct nf_conn *ct, enum ip_conntrack_info ctinfo) | |
1414 | { | |
1415 | struct tcphdr *th, _tcph; | |
1416 | unsigned int dataoff, datalen; | |
1417 | unsigned int matchoff, matchlen, clen; | |
1418 | unsigned int msglen, origlen; | |
1419 | const char *dptr, *end; | |
1420 | s16 diff, tdiff = 0; | |
1421 | int ret = NF_ACCEPT; | |
1422 | typeof(nf_nat_sip_seq_adjust_hook) nf_nat_sip_seq_adjust; | |
1423 | ||
1424 | if (ctinfo != IP_CT_ESTABLISHED && | |
1425 | ctinfo != IP_CT_ESTABLISHED + IP_CT_IS_REPLY) | |
1426 | return NF_ACCEPT; | |
1427 | ||
1428 | /* No Data ? */ | |
1429 | th = skb_header_pointer(skb, protoff, sizeof(_tcph), &_tcph); | |
1430 | if (th == NULL) | |
1431 | return NF_ACCEPT; | |
1432 | dataoff = protoff + th->doff * 4; | |
1433 | if (dataoff >= skb->len) | |
1434 | return NF_ACCEPT; | |
1435 | ||
1436 | nf_ct_refresh(ct, skb, sip_timeout * HZ); | |
1437 | ||
1438 | if (unlikely(skb_linearize(skb))) | |
1439 | return NF_DROP; | |
1440 | ||
1441 | dptr = skb->data + dataoff; | |
1442 | datalen = skb->len - dataoff; | |
1443 | if (datalen < strlen("SIP/2.0 200")) | |
1444 | return NF_ACCEPT; | |
1445 | ||
1446 | while (1) { | |
1447 | if (ct_sip_get_header(ct, dptr, 0, datalen, | |
1448 | SIP_HDR_CONTENT_LENGTH, | |
1449 | &matchoff, &matchlen) <= 0) | |
1450 | break; | |
1451 | ||
1452 | clen = simple_strtoul(dptr + matchoff, (char **)&end, 10); | |
1453 | if (dptr + matchoff == end) | |
1454 | break; | |
1455 | ||
1456 | if (end + strlen("\r\n\r\n") > dptr + datalen) | |
1457 | break; | |
1458 | if (end[0] != '\r' || end[1] != '\n' || | |
1459 | end[2] != '\r' || end[3] != '\n') | |
1460 | break; | |
1461 | end += strlen("\r\n\r\n") + clen; | |
1462 | ||
1463 | msglen = origlen = end - dptr; | |
1464 | ||
1465 | ret = process_sip_msg(skb, ct, dataoff, &dptr, &msglen); | |
1466 | if (ret != NF_ACCEPT) | |
1467 | break; | |
1468 | diff = msglen - origlen; | |
1469 | tdiff += diff; | |
1470 | ||
1471 | dataoff += msglen; | |
1472 | dptr += msglen; | |
1473 | datalen = datalen + diff - msglen; | |
1474 | } | |
1475 | ||
1476 | if (ret == NF_ACCEPT && ct->status & IPS_NAT_MASK) { | |
1477 | nf_nat_sip_seq_adjust = rcu_dereference(nf_nat_sip_seq_adjust_hook); | |
1478 | if (nf_nat_sip_seq_adjust) | |
1479 | nf_nat_sip_seq_adjust(skb, tdiff); | |
1480 | } | |
1481 | ||
1482 | return ret; | |
1483 | } | |
1484 | ||
1485 | static int sip_help_udp(struct sk_buff *skb, unsigned int protoff, | |
1486 | struct nf_conn *ct, enum ip_conntrack_info ctinfo) | |
1487 | { | |
1488 | unsigned int dataoff, datalen; | |
1489 | const char *dptr; | |
1490 | ||
1491 | /* No Data ? */ | |
1492 | dataoff = protoff + sizeof(struct udphdr); | |
1493 | if (dataoff >= skb->len) | |
1494 | return NF_ACCEPT; | |
1495 | ||
1496 | nf_ct_refresh(ct, skb, sip_timeout * HZ); | |
1497 | ||
1498 | if (unlikely(skb_linearize(skb))) | |
1499 | return NF_DROP; | |
1500 | ||
1501 | dptr = skb->data + dataoff; | |
1502 | datalen = skb->len - dataoff; | |
1503 | if (datalen < strlen("SIP/2.0 200")) | |
1504 | return NF_ACCEPT; | |
1505 | ||
1506 | return process_sip_msg(skb, ct, dataoff, &dptr, &datalen); | |
1507 | } | |
1508 | ||
1509 | static struct nf_conntrack_helper sip[MAX_PORTS][4] __read_mostly; | |
1510 | static char sip_names[MAX_PORTS][4][sizeof("sip-65535")] __read_mostly; | |
1511 | ||
1512 | static const struct nf_conntrack_expect_policy sip_exp_policy[SIP_EXPECT_MAX + 1] = { | |
1513 | [SIP_EXPECT_SIGNALLING] = { | |
1514 | .name = "signalling", | |
1515 | .max_expected = 1, | |
1516 | .timeout = 3 * 60, | |
1517 | }, | |
1518 | [SIP_EXPECT_AUDIO] = { | |
1519 | .name = "audio", | |
1520 | .max_expected = 2 * IP_CT_DIR_MAX, | |
1521 | .timeout = 3 * 60, | |
1522 | }, | |
1523 | [SIP_EXPECT_VIDEO] = { | |
1524 | .name = "video", | |
1525 | .max_expected = 2 * IP_CT_DIR_MAX, | |
1526 | .timeout = 3 * 60, | |
1527 | }, | |
1528 | [SIP_EXPECT_IMAGE] = { | |
1529 | .name = "image", | |
1530 | .max_expected = IP_CT_DIR_MAX, | |
1531 | .timeout = 3 * 60, | |
1532 | }, | |
1533 | }; | |
1534 | ||
1535 | static void nf_conntrack_sip_fini(void) | |
1536 | { | |
1537 | int i, j; | |
1538 | ||
1539 | for (i = 0; i < ports_c; i++) { | |
1540 | for (j = 0; j < ARRAY_SIZE(sip[i]); j++) { | |
1541 | if (sip[i][j].me == NULL) | |
1542 | continue; | |
1543 | nf_conntrack_helper_unregister(&sip[i][j]); | |
1544 | } | |
1545 | } | |
1546 | } | |
1547 | ||
1548 | static int __init nf_conntrack_sip_init(void) | |
1549 | { | |
1550 | int i, j, ret; | |
1551 | char *tmpname; | |
1552 | ||
1553 | if (ports_c == 0) | |
1554 | ports[ports_c++] = SIP_PORT; | |
1555 | ||
1556 | for (i = 0; i < ports_c; i++) { | |
1557 | memset(&sip[i], 0, sizeof(sip[i])); | |
1558 | ||
1559 | sip[i][0].tuple.src.l3num = AF_INET; | |
1560 | sip[i][0].tuple.dst.protonum = IPPROTO_UDP; | |
1561 | sip[i][0].help = sip_help_udp; | |
1562 | sip[i][1].tuple.src.l3num = AF_INET; | |
1563 | sip[i][1].tuple.dst.protonum = IPPROTO_TCP; | |
1564 | sip[i][1].help = sip_help_tcp; | |
1565 | ||
1566 | sip[i][2].tuple.src.l3num = AF_INET6; | |
1567 | sip[i][2].tuple.dst.protonum = IPPROTO_UDP; | |
1568 | sip[i][2].help = sip_help_udp; | |
1569 | sip[i][3].tuple.src.l3num = AF_INET6; | |
1570 | sip[i][3].tuple.dst.protonum = IPPROTO_TCP; | |
1571 | sip[i][3].help = sip_help_tcp; | |
1572 | ||
1573 | for (j = 0; j < ARRAY_SIZE(sip[i]); j++) { | |
1574 | sip[i][j].tuple.src.u.udp.port = htons(ports[i]); | |
1575 | sip[i][j].expect_policy = sip_exp_policy; | |
1576 | sip[i][j].expect_class_max = SIP_EXPECT_MAX; | |
1577 | sip[i][j].me = THIS_MODULE; | |
1578 | ||
1579 | tmpname = &sip_names[i][j][0]; | |
1580 | if (ports[i] == SIP_PORT) | |
1581 | sprintf(tmpname, "sip"); | |
1582 | else | |
1583 | sprintf(tmpname, "sip-%u", i); | |
1584 | sip[i][j].name = tmpname; | |
1585 | ||
1586 | pr_debug("port #%u: %u\n", i, ports[i]); | |
1587 | ||
1588 | ret = nf_conntrack_helper_register(&sip[i][j]); | |
1589 | if (ret) { | |
1590 | printk(KERN_ERR "nf_ct_sip: failed to register" | |
1591 | " helper for pf: %u port: %u\n", | |
1592 | sip[i][j].tuple.src.l3num, ports[i]); | |
1593 | nf_conntrack_sip_fini(); | |
1594 | return ret; | |
1595 | } | |
1596 | } | |
1597 | } | |
1598 | return 0; | |
1599 | } | |
1600 | ||
1601 | module_init(nf_conntrack_sip_init); | |
1602 | module_exit(nf_conntrack_sip_fini); |