Commit | Line | Data |
---|---|---|
48f8ac26 | 1 | /* SIP extension for NAT alteration. |
9fafcd7b PM |
2 | * |
3 | * (C) 2005 by Christian Hentschel <chentschel@arnet.com.ar> | |
4 | * based on RR's ip_nat_ftp.c and other modules. | |
f49e1aa1 | 5 | * (C) 2007 United Security Providers |
9a664821 | 6 | * (C) 2007, 2008, 2011, 2012 Patrick McHardy <kaber@trash.net> |
9fafcd7b PM |
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/skbuff.h> | |
9a664821 | 15 | #include <linux/inet.h> |
9fafcd7b | 16 | #include <linux/udp.h> |
48f8ac26 | 17 | #include <linux/tcp.h> |
9fafcd7b PM |
18 | |
19 | #include <net/netfilter/nf_nat.h> | |
20 | #include <net/netfilter/nf_nat_helper.h> | |
9fafcd7b PM |
21 | #include <net/netfilter/nf_conntrack_helper.h> |
22 | #include <net/netfilter/nf_conntrack_expect.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 NAT helper"); | |
28 | MODULE_ALIAS("ip_nat_sip"); | |
29 | ||
9fafcd7b | 30 | |
051966c0 PM |
31 | static unsigned int mangle_packet(struct sk_buff *skb, unsigned int protoff, |
32 | unsigned int dataoff, | |
2a6cfb22 PM |
33 | const char **dptr, unsigned int *datalen, |
34 | unsigned int matchoff, unsigned int matchlen, | |
35 | const char *buffer, unsigned int buflen) | |
36 | { | |
37 | enum ip_conntrack_info ctinfo; | |
38 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
48f8ac26 PM |
39 | struct tcphdr *th; |
40 | unsigned int baseoff; | |
41 | ||
42 | if (nf_ct_protonum(ct) == IPPROTO_TCP) { | |
9a664821 PM |
43 | th = (struct tcphdr *)(skb->data + protoff); |
44 | baseoff = protoff + th->doff * 4; | |
48f8ac26 PM |
45 | matchoff += dataoff - baseoff; |
46 | ||
47 | if (!__nf_nat_mangle_tcp_packet(skb, ct, ctinfo, | |
051966c0 | 48 | protoff, matchoff, matchlen, |
48f8ac26 PM |
49 | buffer, buflen, false)) |
50 | return 0; | |
51 | } else { | |
9a664821 | 52 | baseoff = protoff + sizeof(struct udphdr); |
48f8ac26 PM |
53 | matchoff += dataoff - baseoff; |
54 | ||
55 | if (!nf_nat_mangle_udp_packet(skb, ct, ctinfo, | |
051966c0 | 56 | protoff, matchoff, matchlen, |
48f8ac26 PM |
57 | buffer, buflen)) |
58 | return 0; | |
59 | } | |
2a6cfb22 PM |
60 | |
61 | /* Reload data pointer and adjust datalen value */ | |
3b6b9fab | 62 | *dptr = skb->data + dataoff; |
2a6cfb22 PM |
63 | *datalen += buflen - matchlen; |
64 | return 1; | |
65 | } | |
66 | ||
9a664821 PM |
67 | static int sip_sprintf_addr(const struct nf_conn *ct, char *buffer, |
68 | const union nf_inet_addr *addr, bool delim) | |
69 | { | |
70 | if (nf_ct_l3num(ct) == NFPROTO_IPV4) | |
71 | return sprintf(buffer, "%pI4", &addr->ip); | |
72 | else { | |
73 | if (delim) | |
74 | return sprintf(buffer, "[%pI6c]", &addr->ip6); | |
75 | else | |
76 | return sprintf(buffer, "%pI6c", &addr->ip6); | |
77 | } | |
78 | } | |
79 | ||
80 | static int sip_sprintf_addr_port(const struct nf_conn *ct, char *buffer, | |
81 | const union nf_inet_addr *addr, u16 port) | |
82 | { | |
83 | if (nf_ct_l3num(ct) == NFPROTO_IPV4) | |
84 | return sprintf(buffer, "%pI4:%u", &addr->ip, port); | |
85 | else | |
86 | return sprintf(buffer, "[%pI6c]:%u", &addr->ip6, port); | |
87 | } | |
88 | ||
051966c0 PM |
89 | static int map_addr(struct sk_buff *skb, unsigned int protoff, |
90 | unsigned int dataoff, | |
ac367740 PM |
91 | const char **dptr, unsigned int *datalen, |
92 | unsigned int matchoff, unsigned int matchlen, | |
624f8b7b | 93 | union nf_inet_addr *addr, __be16 port) |
9fafcd7b | 94 | { |
212440a7 | 95 | enum ip_conntrack_info ctinfo; |
624f8b7b | 96 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); |
9fafcd7b | 97 | enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); |
9a664821 | 98 | char buffer[INET6_ADDRSTRLEN + sizeof("[]:nnnnn")]; |
624f8b7b | 99 | unsigned int buflen; |
9a664821 | 100 | union nf_inet_addr newaddr; |
624f8b7b PM |
101 | __be16 newport; |
102 | ||
9a664821 | 103 | if (nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.src.u3, addr) && |
624f8b7b | 104 | ct->tuplehash[dir].tuple.src.u.udp.port == port) { |
9a664821 | 105 | newaddr = ct->tuplehash[!dir].tuple.dst.u3; |
624f8b7b | 106 | newport = ct->tuplehash[!dir].tuple.dst.u.udp.port; |
9a664821 | 107 | } else if (nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.dst.u3, addr) && |
624f8b7b | 108 | ct->tuplehash[dir].tuple.dst.u.udp.port == port) { |
9a664821 | 109 | newaddr = ct->tuplehash[!dir].tuple.src.u3; |
624f8b7b | 110 | newport = ct->tuplehash[!dir].tuple.src.u.udp.port; |
9fafcd7b PM |
111 | } else |
112 | return 1; | |
113 | ||
9a664821 | 114 | if (nf_inet_addr_cmp(&newaddr, addr) && newport == port) |
624f8b7b PM |
115 | return 1; |
116 | ||
9a664821 | 117 | buflen = sip_sprintf_addr_port(ct, buffer, &newaddr, ntohs(newport)); |
051966c0 PM |
118 | return mangle_packet(skb, protoff, dataoff, dptr, datalen, |
119 | matchoff, matchlen, buffer, buflen); | |
9fafcd7b PM |
120 | } |
121 | ||
051966c0 PM |
122 | static int map_sip_addr(struct sk_buff *skb, unsigned int protoff, |
123 | unsigned int dataoff, | |
ac367740 | 124 | const char **dptr, unsigned int *datalen, |
624f8b7b | 125 | enum sip_header_types type) |
ac367740 PM |
126 | { |
127 | enum ip_conntrack_info ctinfo; | |
128 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
129 | unsigned int matchlen, matchoff; | |
624f8b7b PM |
130 | union nf_inet_addr addr; |
131 | __be16 port; | |
ac367740 | 132 | |
624f8b7b PM |
133 | if (ct_sip_parse_header_uri(ct, *dptr, NULL, *datalen, type, NULL, |
134 | &matchoff, &matchlen, &addr, &port) <= 0) | |
ac367740 | 135 | return 1; |
051966c0 PM |
136 | return map_addr(skb, protoff, dataoff, dptr, datalen, |
137 | matchoff, matchlen, &addr, port); | |
ac367740 PM |
138 | } |
139 | ||
9a664821 | 140 | static unsigned int nf_nat_sip(struct sk_buff *skb, unsigned int protoff, |
051966c0 | 141 | unsigned int dataoff, |
2a6cfb22 | 142 | const char **dptr, unsigned int *datalen) |
9fafcd7b | 143 | { |
212440a7 PM |
144 | enum ip_conntrack_info ctinfo; |
145 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
720ac708 | 146 | enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); |
3b6b9fab | 147 | unsigned int coff, matchoff, matchlen; |
48f8ac26 | 148 | enum sip_header_types hdr; |
624f8b7b PM |
149 | union nf_inet_addr addr; |
150 | __be16 port; | |
c978cd3a | 151 | int request, in_header; |
9fafcd7b | 152 | |
9fafcd7b | 153 | /* Basic rules: requests and responses. */ |
779382eb | 154 | if (strnicmp(*dptr, "SIP/2.0", strlen("SIP/2.0")) != 0) { |
ac367740 | 155 | if (ct_sip_parse_request(ct, *dptr, *datalen, |
624f8b7b PM |
156 | &matchoff, &matchlen, |
157 | &addr, &port) > 0 && | |
051966c0 PM |
158 | !map_addr(skb, protoff, dataoff, dptr, datalen, |
159 | matchoff, matchlen, &addr, port)) | |
9fafcd7b | 160 | return NF_DROP; |
720ac708 PM |
161 | request = 1; |
162 | } else | |
163 | request = 0; | |
164 | ||
48f8ac26 PM |
165 | if (nf_ct_protonum(ct) == IPPROTO_TCP) |
166 | hdr = SIP_HDR_VIA_TCP; | |
167 | else | |
168 | hdr = SIP_HDR_VIA_UDP; | |
169 | ||
720ac708 PM |
170 | /* Translate topmost Via header and parameters */ |
171 | if (ct_sip_parse_header_uri(ct, *dptr, NULL, *datalen, | |
48f8ac26 | 172 | hdr, NULL, &matchoff, &matchlen, |
720ac708 | 173 | &addr, &port) > 0) { |
f22eb25c | 174 | unsigned int olen, matchend, poff, plen, buflen, n; |
9a664821 | 175 | char buffer[INET6_ADDRSTRLEN + sizeof("[]:nnnnn")]; |
720ac708 PM |
176 | |
177 | /* We're only interested in headers related to this | |
178 | * connection */ | |
179 | if (request) { | |
9a664821 PM |
180 | if (!nf_inet_addr_cmp(&addr, |
181 | &ct->tuplehash[dir].tuple.src.u3) || | |
720ac708 PM |
182 | port != ct->tuplehash[dir].tuple.src.u.udp.port) |
183 | goto next; | |
184 | } else { | |
9a664821 PM |
185 | if (!nf_inet_addr_cmp(&addr, |
186 | &ct->tuplehash[dir].tuple.dst.u3) || | |
720ac708 PM |
187 | port != ct->tuplehash[dir].tuple.dst.u.udp.port) |
188 | goto next; | |
189 | } | |
190 | ||
f22eb25c | 191 | olen = *datalen; |
051966c0 PM |
192 | if (!map_addr(skb, protoff, dataoff, dptr, datalen, |
193 | matchoff, matchlen, &addr, port)) | |
720ac708 PM |
194 | return NF_DROP; |
195 | ||
f22eb25c | 196 | matchend = matchoff + matchlen + *datalen - olen; |
720ac708 PM |
197 | |
198 | /* The maddr= parameter (RFC 2361) specifies where to send | |
199 | * the reply. */ | |
200 | if (ct_sip_parse_address_param(ct, *dptr, matchend, *datalen, | |
201 | "maddr=", &poff, &plen, | |
02b69cbd | 202 | &addr, true) > 0 && |
9a664821 PM |
203 | nf_inet_addr_cmp(&addr, &ct->tuplehash[dir].tuple.src.u3) && |
204 | !nf_inet_addr_cmp(&addr, &ct->tuplehash[!dir].tuple.dst.u3)) { | |
205 | buflen = sip_sprintf_addr(ct, buffer, | |
206 | &ct->tuplehash[!dir].tuple.dst.u3, | |
207 | true); | |
051966c0 | 208 | if (!mangle_packet(skb, protoff, dataoff, dptr, datalen, |
3b6b9fab | 209 | poff, plen, buffer, buflen)) |
720ac708 PM |
210 | return NF_DROP; |
211 | } | |
212 | ||
213 | /* The received= parameter (RFC 2361) contains the address | |
214 | * from which the server received the request. */ | |
215 | if (ct_sip_parse_address_param(ct, *dptr, matchend, *datalen, | |
216 | "received=", &poff, &plen, | |
02b69cbd | 217 | &addr, false) > 0 && |
9a664821 PM |
218 | nf_inet_addr_cmp(&addr, &ct->tuplehash[dir].tuple.dst.u3) && |
219 | !nf_inet_addr_cmp(&addr, &ct->tuplehash[!dir].tuple.src.u3)) { | |
220 | buflen = sip_sprintf_addr(ct, buffer, | |
221 | &ct->tuplehash[!dir].tuple.src.u3, | |
222 | false); | |
051966c0 | 223 | if (!mangle_packet(skb, protoff, dataoff, dptr, datalen, |
3b6b9fab | 224 | poff, plen, buffer, buflen)) |
720ac708 PM |
225 | return NF_DROP; |
226 | } | |
227 | ||
228 | /* The rport= parameter (RFC 3581) contains the port number | |
229 | * from which the server received the request. */ | |
230 | if (ct_sip_parse_numerical_param(ct, *dptr, matchend, *datalen, | |
231 | "rport=", &poff, &plen, | |
232 | &n) > 0 && | |
233 | htons(n) == ct->tuplehash[dir].tuple.dst.u.udp.port && | |
234 | htons(n) != ct->tuplehash[!dir].tuple.src.u.udp.port) { | |
235 | __be16 p = ct->tuplehash[!dir].tuple.src.u.udp.port; | |
236 | buflen = sprintf(buffer, "%u", ntohs(p)); | |
051966c0 | 237 | if (!mangle_packet(skb, protoff, dataoff, dptr, datalen, |
3b6b9fab | 238 | poff, plen, buffer, buflen)) |
720ac708 PM |
239 | return NF_DROP; |
240 | } | |
9fafcd7b PM |
241 | } |
242 | ||
720ac708 | 243 | next: |
c978cd3a | 244 | /* Translate Contact headers */ |
3b6b9fab | 245 | coff = 0; |
c978cd3a | 246 | in_header = 0; |
3b6b9fab | 247 | while (ct_sip_parse_header_uri(ct, *dptr, &coff, *datalen, |
c978cd3a PM |
248 | SIP_HDR_CONTACT, &in_header, |
249 | &matchoff, &matchlen, | |
250 | &addr, &port) > 0) { | |
051966c0 PM |
251 | if (!map_addr(skb, protoff, dataoff, dptr, datalen, |
252 | matchoff, matchlen, | |
c978cd3a PM |
253 | &addr, port)) |
254 | return NF_DROP; | |
255 | } | |
256 | ||
051966c0 PM |
257 | if (!map_sip_addr(skb, protoff, dataoff, dptr, datalen, SIP_HDR_FROM) || |
258 | !map_sip_addr(skb, protoff, dataoff, dptr, datalen, SIP_HDR_TO)) | |
9fafcd7b | 259 | return NF_DROP; |
48f8ac26 | 260 | |
9fafcd7b PM |
261 | return NF_ACCEPT; |
262 | } | |
263 | ||
9a664821 PM |
264 | static void nf_nat_sip_seq_adjust(struct sk_buff *skb, unsigned int protoff, |
265 | s16 off) | |
48f8ac26 PM |
266 | { |
267 | enum ip_conntrack_info ctinfo; | |
268 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
269 | const struct tcphdr *th; | |
270 | ||
271 | if (nf_ct_protonum(ct) != IPPROTO_TCP || off == 0) | |
272 | return; | |
273 | ||
9a664821 | 274 | th = (struct tcphdr *)(skb->data + protoff); |
48f8ac26 PM |
275 | nf_nat_set_seq_adjust(ct, ctinfo, th->seq, off); |
276 | } | |
277 | ||
0f32a40f | 278 | /* Handles expected signalling connections and media streams */ |
9a664821 | 279 | static void nf_nat_sip_expected(struct nf_conn *ct, |
0f32a40f PM |
280 | struct nf_conntrack_expect *exp) |
281 | { | |
c7232c99 | 282 | struct nf_nat_range range; |
0f32a40f PM |
283 | |
284 | /* This must be a fresh one. */ | |
285 | BUG_ON(ct->status & IPS_NAT_DONE_MASK); | |
286 | ||
287 | /* For DST manip, map port here to where it's expected. */ | |
cbc9f2f4 | 288 | range.flags = (NF_NAT_RANGE_MAP_IPS | NF_NAT_RANGE_PROTO_SPECIFIED); |
c7232c99 PM |
289 | range.min_proto = range.max_proto = exp->saved_proto; |
290 | range.min_addr = range.max_addr = exp->saved_addr; | |
cbc9f2f4 | 291 | nf_nat_setup_info(ct, &range, NF_NAT_MANIP_DST); |
0f32a40f PM |
292 | |
293 | /* Change src to where master sends to, but only if the connection | |
294 | * actually came from the same source. */ | |
9a664821 PM |
295 | if (nf_inet_addr_cmp(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3, |
296 | &ct->master->tuplehash[exp->dir].tuple.src.u3)) { | |
cbc9f2f4 | 297 | range.flags = NF_NAT_RANGE_MAP_IPS; |
c7232c99 PM |
298 | range.min_addr = range.max_addr |
299 | = ct->master->tuplehash[!exp->dir].tuple.dst.u3; | |
cbc9f2f4 | 300 | nf_nat_setup_info(ct, &range, NF_NAT_MANIP_SRC); |
0f32a40f PM |
301 | } |
302 | } | |
303 | ||
9a664821 | 304 | static unsigned int nf_nat_sip_expect(struct sk_buff *skb, unsigned int protoff, |
051966c0 | 305 | unsigned int dataoff, |
0f32a40f PM |
306 | const char **dptr, unsigned int *datalen, |
307 | struct nf_conntrack_expect *exp, | |
308 | unsigned int matchoff, | |
309 | unsigned int matchlen) | |
310 | { | |
311 | enum ip_conntrack_info ctinfo; | |
312 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
313 | enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); | |
9a664821 | 314 | union nf_inet_addr newaddr; |
0f32a40f | 315 | u_int16_t port; |
9a664821 | 316 | char buffer[INET6_ADDRSTRLEN + sizeof("[]:nnnnn")]; |
95c96174 | 317 | unsigned int buflen; |
0f32a40f PM |
318 | |
319 | /* Connection will come from reply */ | |
9a664821 PM |
320 | if (nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.src.u3, |
321 | &ct->tuplehash[!dir].tuple.dst.u3)) | |
322 | newaddr = exp->tuple.dst.u3; | |
0f32a40f | 323 | else |
9a664821 | 324 | newaddr = ct->tuplehash[!dir].tuple.dst.u3; |
0f32a40f PM |
325 | |
326 | /* If the signalling port matches the connection's source port in the | |
327 | * original direction, try to use the destination port in the opposite | |
328 | * direction. */ | |
329 | if (exp->tuple.dst.u.udp.port == | |
330 | ct->tuplehash[dir].tuple.src.u.udp.port) | |
331 | port = ntohs(ct->tuplehash[!dir].tuple.dst.u.udp.port); | |
332 | else | |
333 | port = ntohs(exp->tuple.dst.u.udp.port); | |
334 | ||
c7232c99 | 335 | exp->saved_addr = exp->tuple.dst.u3; |
9a664821 | 336 | exp->tuple.dst.u3 = newaddr; |
0f32a40f PM |
337 | exp->saved_proto.udp.port = exp->tuple.dst.u.udp.port; |
338 | exp->dir = !dir; | |
9a664821 | 339 | exp->expectfn = nf_nat_sip_expected; |
0f32a40f PM |
340 | |
341 | for (; port != 0; port++) { | |
5b92b61f PNA |
342 | int ret; |
343 | ||
0f32a40f | 344 | exp->tuple.dst.u.udp.port = htons(port); |
5b92b61f PNA |
345 | ret = nf_ct_expect_related(exp); |
346 | if (ret == 0) | |
347 | break; | |
348 | else if (ret != -EBUSY) { | |
349 | port = 0; | |
0f32a40f | 350 | break; |
5b92b61f | 351 | } |
0f32a40f PM |
352 | } |
353 | ||
354 | if (port == 0) | |
355 | return NF_DROP; | |
356 | ||
9a664821 | 357 | if (!nf_inet_addr_cmp(&exp->tuple.dst.u3, &exp->saved_addr) || |
0f32a40f | 358 | exp->tuple.dst.u.udp.port != exp->saved_proto.udp.port) { |
9a664821 | 359 | buflen = sip_sprintf_addr_port(ct, buffer, &newaddr, port); |
051966c0 | 360 | if (!mangle_packet(skb, protoff, dataoff, dptr, datalen, |
3b6b9fab | 361 | matchoff, matchlen, buffer, buflen)) |
0f32a40f PM |
362 | goto err; |
363 | } | |
364 | return NF_ACCEPT; | |
365 | ||
366 | err: | |
367 | nf_ct_unexpect_related(exp); | |
368 | return NF_DROP; | |
369 | } | |
370 | ||
051966c0 PM |
371 | static int mangle_content_len(struct sk_buff *skb, unsigned int protoff, |
372 | unsigned int dataoff, | |
3e9b4600 | 373 | const char **dptr, unsigned int *datalen) |
9fafcd7b | 374 | { |
212440a7 PM |
375 | enum ip_conntrack_info ctinfo; |
376 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
3e9b4600 PM |
377 | unsigned int matchoff, matchlen; |
378 | char buffer[sizeof("65536")]; | |
379 | int buflen, c_len; | |
9fafcd7b | 380 | |
3e9b4600 PM |
381 | /* Get actual SDP length */ |
382 | if (ct_sip_get_sdp_header(ct, *dptr, 0, *datalen, | |
383 | SDP_HDR_VERSION, SDP_HDR_UNSPEC, | |
384 | &matchoff, &matchlen) <= 0) | |
385 | return 0; | |
386 | c_len = *datalen - matchoff + strlen("v="); | |
387 | ||
388 | /* Now, update SDP length */ | |
ea45f12a PM |
389 | if (ct_sip_get_header(ct, *dptr, 0, *datalen, SIP_HDR_CONTENT_LENGTH, |
390 | &matchoff, &matchlen) <= 0) | |
9fafcd7b PM |
391 | return 0; |
392 | ||
3e9b4600 | 393 | buflen = sprintf(buffer, "%u", c_len); |
051966c0 PM |
394 | return mangle_packet(skb, protoff, dataoff, dptr, datalen, |
395 | matchoff, matchlen, buffer, buflen); | |
9fafcd7b PM |
396 | } |
397 | ||
051966c0 PM |
398 | static int mangle_sdp_packet(struct sk_buff *skb, unsigned int protoff, |
399 | unsigned int dataoff, | |
3b6b9fab PM |
400 | const char **dptr, unsigned int *datalen, |
401 | unsigned int sdpoff, | |
c71529e4 HX |
402 | enum sdp_header_types type, |
403 | enum sdp_header_types term, | |
404 | char *buffer, int buflen) | |
9fafcd7b | 405 | { |
212440a7 PM |
406 | enum ip_conntrack_info ctinfo; |
407 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
3e9b4600 | 408 | unsigned int matchlen, matchoff; |
9fafcd7b | 409 | |
3b6b9fab | 410 | if (ct_sip_get_sdp_header(ct, *dptr, sdpoff, *datalen, type, term, |
3e9b4600 | 411 | &matchoff, &matchlen) <= 0) |
c71529e4 | 412 | return -ENOENT; |
051966c0 PM |
413 | return mangle_packet(skb, protoff, dataoff, dptr, datalen, |
414 | matchoff, matchlen, buffer, buflen) ? 0 : -EINVAL; | |
9fafcd7b PM |
415 | } |
416 | ||
9a664821 | 417 | static unsigned int nf_nat_sdp_addr(struct sk_buff *skb, unsigned int protoff, |
051966c0 | 418 | unsigned int dataoff, |
3b6b9fab PM |
419 | const char **dptr, unsigned int *datalen, |
420 | unsigned int sdpoff, | |
4ab9e64e PM |
421 | enum sdp_header_types type, |
422 | enum sdp_header_types term, | |
423 | const union nf_inet_addr *addr) | |
9fafcd7b | 424 | { |
9a664821 PM |
425 | enum ip_conntrack_info ctinfo; |
426 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
427 | char buffer[INET6_ADDRSTRLEN]; | |
4ab9e64e | 428 | unsigned int buflen; |
9fafcd7b | 429 | |
9a664821 | 430 | buflen = sip_sprintf_addr(ct, buffer, addr, false); |
051966c0 PM |
431 | if (mangle_sdp_packet(skb, protoff, dataoff, dptr, datalen, |
432 | sdpoff, type, term, buffer, buflen)) | |
9fafcd7b PM |
433 | return 0; |
434 | ||
051966c0 | 435 | return mangle_content_len(skb, protoff, dataoff, dptr, datalen); |
4ab9e64e PM |
436 | } |
437 | ||
9a664821 | 438 | static unsigned int nf_nat_sdp_port(struct sk_buff *skb, unsigned int protoff, |
051966c0 | 439 | unsigned int dataoff, |
3b6b9fab | 440 | const char **dptr, unsigned int *datalen, |
4ab9e64e PM |
441 | unsigned int matchoff, |
442 | unsigned int matchlen, | |
443 | u_int16_t port) | |
444 | { | |
445 | char buffer[sizeof("nnnnn")]; | |
446 | unsigned int buflen; | |
447 | ||
448 | buflen = sprintf(buffer, "%u", port); | |
051966c0 PM |
449 | if (!mangle_packet(skb, protoff, dataoff, dptr, datalen, |
450 | matchoff, matchlen, buffer, buflen)) | |
9fafcd7b PM |
451 | return 0; |
452 | ||
051966c0 | 453 | return mangle_content_len(skb, protoff, dataoff, dptr, datalen); |
4ab9e64e PM |
454 | } |
455 | ||
9a664821 | 456 | static unsigned int nf_nat_sdp_session(struct sk_buff *skb, unsigned int protoff, |
051966c0 | 457 | unsigned int dataoff, |
3b6b9fab PM |
458 | const char **dptr, unsigned int *datalen, |
459 | unsigned int sdpoff, | |
4ab9e64e PM |
460 | const union nf_inet_addr *addr) |
461 | { | |
9a664821 PM |
462 | enum ip_conntrack_info ctinfo; |
463 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
464 | char buffer[INET6_ADDRSTRLEN]; | |
4ab9e64e PM |
465 | unsigned int buflen; |
466 | ||
467 | /* Mangle session description owner and contact addresses */ | |
9a664821 | 468 | buflen = sip_sprintf_addr(ct, buffer, addr, false); |
051966c0 | 469 | if (mangle_sdp_packet(skb, protoff, dataoff, dptr, datalen, sdpoff, |
9a664821 | 470 | SDP_HDR_OWNER, SDP_HDR_MEDIA, buffer, buflen)) |
4ab9e64e PM |
471 | return 0; |
472 | ||
051966c0 | 473 | switch (mangle_sdp_packet(skb, protoff, dataoff, dptr, datalen, sdpoff, |
9a664821 | 474 | SDP_HDR_CONNECTION, SDP_HDR_MEDIA, |
c71529e4 HX |
475 | buffer, buflen)) { |
476 | case 0: | |
477 | /* | |
478 | * RFC 2327: | |
479 | * | |
480 | * Session description | |
481 | * | |
482 | * c=* (connection information - not required if included in all media) | |
483 | */ | |
484 | case -ENOENT: | |
485 | break; | |
486 | default: | |
9fafcd7b | 487 | return 0; |
c71529e4 | 488 | } |
9fafcd7b | 489 | |
051966c0 | 490 | return mangle_content_len(skb, protoff, dataoff, dptr, datalen); |
9fafcd7b PM |
491 | } |
492 | ||
493 | /* So, this packet has hit the connection tracking matching code. | |
494 | Mangle it, and change the expectation to match the new version. */ | |
9a664821 | 495 | static unsigned int nf_nat_sdp_media(struct sk_buff *skb, unsigned int protoff, |
051966c0 | 496 | unsigned int dataoff, |
3b6b9fab | 497 | const char **dptr, unsigned int *datalen, |
4ab9e64e PM |
498 | struct nf_conntrack_expect *rtp_exp, |
499 | struct nf_conntrack_expect *rtcp_exp, | |
500 | unsigned int mediaoff, | |
501 | unsigned int medialen, | |
502 | union nf_inet_addr *rtp_addr) | |
9fafcd7b | 503 | { |
212440a7 PM |
504 | enum ip_conntrack_info ctinfo; |
505 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
9fafcd7b | 506 | enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); |
9fafcd7b PM |
507 | u_int16_t port; |
508 | ||
9fafcd7b | 509 | /* Connection will come from reply */ |
9a664821 PM |
510 | if (nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.src.u3, |
511 | &ct->tuplehash[!dir].tuple.dst.u3)) | |
512 | *rtp_addr = rtp_exp->tuple.dst.u3; | |
f4a607bf | 513 | else |
9a664821 | 514 | *rtp_addr = ct->tuplehash[!dir].tuple.dst.u3; |
9fafcd7b | 515 | |
c7232c99 | 516 | rtp_exp->saved_addr = rtp_exp->tuple.dst.u3; |
9a664821 | 517 | rtp_exp->tuple.dst.u3 = *rtp_addr; |
a9c1d359 PM |
518 | rtp_exp->saved_proto.udp.port = rtp_exp->tuple.dst.u.udp.port; |
519 | rtp_exp->dir = !dir; | |
9a664821 | 520 | rtp_exp->expectfn = nf_nat_sip_expected; |
a9c1d359 | 521 | |
c7232c99 | 522 | rtcp_exp->saved_addr = rtcp_exp->tuple.dst.u3; |
9a664821 | 523 | rtcp_exp->tuple.dst.u3 = *rtp_addr; |
a9c1d359 PM |
524 | rtcp_exp->saved_proto.udp.port = rtcp_exp->tuple.dst.u.udp.port; |
525 | rtcp_exp->dir = !dir; | |
9a664821 | 526 | rtcp_exp->expectfn = nf_nat_sip_expected; |
a9c1d359 PM |
527 | |
528 | /* Try to get same pair of ports: if not, try to change them. */ | |
529 | for (port = ntohs(rtp_exp->tuple.dst.u.udp.port); | |
530 | port != 0; port += 2) { | |
5b92b61f PNA |
531 | int ret; |
532 | ||
a9c1d359 | 533 | rtp_exp->tuple.dst.u.udp.port = htons(port); |
5b92b61f PNA |
534 | ret = nf_ct_expect_related(rtp_exp); |
535 | if (ret == -EBUSY) | |
a9c1d359 | 536 | continue; |
5b92b61f PNA |
537 | else if (ret < 0) { |
538 | port = 0; | |
539 | break; | |
540 | } | |
a9c1d359 | 541 | rtcp_exp->tuple.dst.u.udp.port = htons(port + 1); |
5b92b61f PNA |
542 | ret = nf_ct_expect_related(rtcp_exp); |
543 | if (ret == 0) | |
9fafcd7b | 544 | break; |
3f509c68 PNA |
545 | else if (ret == -EBUSY) { |
546 | nf_ct_unexpect_related(rtp_exp); | |
547 | continue; | |
548 | } else if (ret < 0) { | |
5b92b61f PNA |
549 | nf_ct_unexpect_related(rtp_exp); |
550 | port = 0; | |
551 | break; | |
552 | } | |
9fafcd7b PM |
553 | } |
554 | ||
555 | if (port == 0) | |
4ab9e64e PM |
556 | goto err1; |
557 | ||
558 | /* Update media port. */ | |
559 | if (rtp_exp->tuple.dst.u.udp.port != rtp_exp->saved_proto.udp.port && | |
9a664821 | 560 | !nf_nat_sdp_port(skb, protoff, dataoff, dptr, datalen, |
3b6b9fab | 561 | mediaoff, medialen, port)) |
4ab9e64e | 562 | goto err2; |
9fafcd7b | 563 | |
9fafcd7b | 564 | return NF_ACCEPT; |
4ab9e64e PM |
565 | |
566 | err2: | |
567 | nf_ct_unexpect_related(rtp_exp); | |
568 | nf_ct_unexpect_related(rtcp_exp); | |
569 | err1: | |
570 | return NF_DROP; | |
9fafcd7b PM |
571 | } |
572 | ||
544d5c7d | 573 | static struct nf_ct_helper_expectfn sip_nat = { |
9a664821 PM |
574 | .name = "sip", |
575 | .expectfn = nf_nat_sip_expected, | |
544d5c7d PNA |
576 | }; |
577 | ||
9fafcd7b PM |
578 | static void __exit nf_nat_sip_fini(void) |
579 | { | |
a9b3cd7f SH |
580 | RCU_INIT_POINTER(nf_nat_sip_hook, NULL); |
581 | RCU_INIT_POINTER(nf_nat_sip_seq_adjust_hook, NULL); | |
582 | RCU_INIT_POINTER(nf_nat_sip_expect_hook, NULL); | |
583 | RCU_INIT_POINTER(nf_nat_sdp_addr_hook, NULL); | |
584 | RCU_INIT_POINTER(nf_nat_sdp_port_hook, NULL); | |
585 | RCU_INIT_POINTER(nf_nat_sdp_session_hook, NULL); | |
586 | RCU_INIT_POINTER(nf_nat_sdp_media_hook, NULL); | |
544d5c7d | 587 | nf_ct_helper_expectfn_unregister(&sip_nat); |
9fafcd7b PM |
588 | synchronize_rcu(); |
589 | } | |
590 | ||
591 | static int __init nf_nat_sip_init(void) | |
592 | { | |
d1332e0a | 593 | BUG_ON(nf_nat_sip_hook != NULL); |
48f8ac26 | 594 | BUG_ON(nf_nat_sip_seq_adjust_hook != NULL); |
0f32a40f | 595 | BUG_ON(nf_nat_sip_expect_hook != NULL); |
4ab9e64e | 596 | BUG_ON(nf_nat_sdp_addr_hook != NULL); |
c7f485ab | 597 | BUG_ON(nf_nat_sdp_port_hook != NULL); |
4ab9e64e PM |
598 | BUG_ON(nf_nat_sdp_session_hook != NULL); |
599 | BUG_ON(nf_nat_sdp_media_hook != NULL); | |
9a664821 PM |
600 | RCU_INIT_POINTER(nf_nat_sip_hook, nf_nat_sip); |
601 | RCU_INIT_POINTER(nf_nat_sip_seq_adjust_hook, nf_nat_sip_seq_adjust); | |
602 | RCU_INIT_POINTER(nf_nat_sip_expect_hook, nf_nat_sip_expect); | |
603 | RCU_INIT_POINTER(nf_nat_sdp_addr_hook, nf_nat_sdp_addr); | |
604 | RCU_INIT_POINTER(nf_nat_sdp_port_hook, nf_nat_sdp_port); | |
605 | RCU_INIT_POINTER(nf_nat_sdp_session_hook, nf_nat_sdp_session); | |
606 | RCU_INIT_POINTER(nf_nat_sdp_media_hook, nf_nat_sdp_media); | |
544d5c7d | 607 | nf_ct_helper_expectfn_register(&sip_nat); |
9fafcd7b PM |
608 | return 0; |
609 | } | |
610 | ||
611 | module_init(nf_nat_sip_init); | |
612 | module_exit(nf_nat_sip_fini); |