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); |
7266507d | 98 | struct nf_ct_sip_master *ct_sip_info = nfct_help_data(ct); |
9a664821 | 99 | char buffer[INET6_ADDRSTRLEN + sizeof("[]:nnnnn")]; |
624f8b7b | 100 | unsigned int buflen; |
9a664821 | 101 | union nf_inet_addr newaddr; |
624f8b7b PM |
102 | __be16 newport; |
103 | ||
9a664821 | 104 | if (nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.src.u3, addr) && |
624f8b7b | 105 | ct->tuplehash[dir].tuple.src.u.udp.port == port) { |
9a664821 | 106 | newaddr = ct->tuplehash[!dir].tuple.dst.u3; |
624f8b7b | 107 | newport = ct->tuplehash[!dir].tuple.dst.u.udp.port; |
9a664821 | 108 | } else if (nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.dst.u3, addr) && |
624f8b7b | 109 | ct->tuplehash[dir].tuple.dst.u.udp.port == port) { |
9a664821 | 110 | newaddr = ct->tuplehash[!dir].tuple.src.u3; |
7266507d KC |
111 | newport = ct_sip_info->forced_dport ? : |
112 | ct->tuplehash[!dir].tuple.src.u.udp.port; | |
9fafcd7b PM |
113 | } else |
114 | return 1; | |
115 | ||
9a664821 | 116 | if (nf_inet_addr_cmp(&newaddr, addr) && newport == port) |
624f8b7b PM |
117 | return 1; |
118 | ||
9a664821 | 119 | buflen = sip_sprintf_addr_port(ct, buffer, &newaddr, ntohs(newport)); |
051966c0 PM |
120 | return mangle_packet(skb, protoff, dataoff, dptr, datalen, |
121 | matchoff, matchlen, buffer, buflen); | |
9fafcd7b PM |
122 | } |
123 | ||
051966c0 PM |
124 | static int map_sip_addr(struct sk_buff *skb, unsigned int protoff, |
125 | unsigned int dataoff, | |
ac367740 | 126 | const char **dptr, unsigned int *datalen, |
624f8b7b | 127 | enum sip_header_types type) |
ac367740 PM |
128 | { |
129 | enum ip_conntrack_info ctinfo; | |
130 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
131 | unsigned int matchlen, matchoff; | |
624f8b7b PM |
132 | union nf_inet_addr addr; |
133 | __be16 port; | |
ac367740 | 134 | |
624f8b7b PM |
135 | if (ct_sip_parse_header_uri(ct, *dptr, NULL, *datalen, type, NULL, |
136 | &matchoff, &matchlen, &addr, &port) <= 0) | |
ac367740 | 137 | return 1; |
051966c0 PM |
138 | return map_addr(skb, protoff, dataoff, dptr, datalen, |
139 | matchoff, matchlen, &addr, port); | |
ac367740 PM |
140 | } |
141 | ||
9a664821 | 142 | static unsigned int nf_nat_sip(struct sk_buff *skb, unsigned int protoff, |
051966c0 | 143 | unsigned int dataoff, |
2a6cfb22 | 144 | const char **dptr, unsigned int *datalen) |
9fafcd7b | 145 | { |
212440a7 PM |
146 | enum ip_conntrack_info ctinfo; |
147 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
720ac708 | 148 | enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); |
7266507d | 149 | struct nf_ct_sip_master *ct_sip_info = nfct_help_data(ct); |
3b6b9fab | 150 | unsigned int coff, matchoff, matchlen; |
48f8ac26 | 151 | enum sip_header_types hdr; |
624f8b7b PM |
152 | union nf_inet_addr addr; |
153 | __be16 port; | |
c978cd3a | 154 | int request, in_header; |
9fafcd7b | 155 | |
9fafcd7b | 156 | /* Basic rules: requests and responses. */ |
779382eb | 157 | if (strnicmp(*dptr, "SIP/2.0", strlen("SIP/2.0")) != 0) { |
ac367740 | 158 | if (ct_sip_parse_request(ct, *dptr, *datalen, |
624f8b7b PM |
159 | &matchoff, &matchlen, |
160 | &addr, &port) > 0 && | |
051966c0 PM |
161 | !map_addr(skb, protoff, dataoff, dptr, datalen, |
162 | matchoff, matchlen, &addr, port)) | |
9fafcd7b | 163 | return NF_DROP; |
720ac708 PM |
164 | request = 1; |
165 | } else | |
166 | request = 0; | |
167 | ||
48f8ac26 PM |
168 | if (nf_ct_protonum(ct) == IPPROTO_TCP) |
169 | hdr = SIP_HDR_VIA_TCP; | |
170 | else | |
171 | hdr = SIP_HDR_VIA_UDP; | |
172 | ||
720ac708 PM |
173 | /* Translate topmost Via header and parameters */ |
174 | if (ct_sip_parse_header_uri(ct, *dptr, NULL, *datalen, | |
48f8ac26 | 175 | hdr, NULL, &matchoff, &matchlen, |
720ac708 | 176 | &addr, &port) > 0) { |
f22eb25c | 177 | unsigned int olen, matchend, poff, plen, buflen, n; |
9a664821 | 178 | char buffer[INET6_ADDRSTRLEN + sizeof("[]:nnnnn")]; |
720ac708 PM |
179 | |
180 | /* We're only interested in headers related to this | |
181 | * connection */ | |
182 | if (request) { | |
9a664821 PM |
183 | if (!nf_inet_addr_cmp(&addr, |
184 | &ct->tuplehash[dir].tuple.src.u3) || | |
720ac708 PM |
185 | port != ct->tuplehash[dir].tuple.src.u.udp.port) |
186 | goto next; | |
187 | } else { | |
9a664821 PM |
188 | if (!nf_inet_addr_cmp(&addr, |
189 | &ct->tuplehash[dir].tuple.dst.u3) || | |
720ac708 PM |
190 | port != ct->tuplehash[dir].tuple.dst.u.udp.port) |
191 | goto next; | |
192 | } | |
193 | ||
f22eb25c | 194 | olen = *datalen; |
051966c0 PM |
195 | if (!map_addr(skb, protoff, dataoff, dptr, datalen, |
196 | matchoff, matchlen, &addr, port)) | |
720ac708 PM |
197 | return NF_DROP; |
198 | ||
f22eb25c | 199 | matchend = matchoff + matchlen + *datalen - olen; |
720ac708 PM |
200 | |
201 | /* The maddr= parameter (RFC 2361) specifies where to send | |
202 | * the reply. */ | |
203 | if (ct_sip_parse_address_param(ct, *dptr, matchend, *datalen, | |
204 | "maddr=", &poff, &plen, | |
02b69cbd | 205 | &addr, true) > 0 && |
9a664821 PM |
206 | nf_inet_addr_cmp(&addr, &ct->tuplehash[dir].tuple.src.u3) && |
207 | !nf_inet_addr_cmp(&addr, &ct->tuplehash[!dir].tuple.dst.u3)) { | |
208 | buflen = sip_sprintf_addr(ct, buffer, | |
209 | &ct->tuplehash[!dir].tuple.dst.u3, | |
210 | true); | |
051966c0 | 211 | if (!mangle_packet(skb, protoff, dataoff, dptr, datalen, |
3b6b9fab | 212 | poff, plen, buffer, buflen)) |
720ac708 PM |
213 | return NF_DROP; |
214 | } | |
215 | ||
216 | /* The received= parameter (RFC 2361) contains the address | |
217 | * from which the server received the request. */ | |
218 | if (ct_sip_parse_address_param(ct, *dptr, matchend, *datalen, | |
219 | "received=", &poff, &plen, | |
02b69cbd | 220 | &addr, false) > 0 && |
9a664821 PM |
221 | nf_inet_addr_cmp(&addr, &ct->tuplehash[dir].tuple.dst.u3) && |
222 | !nf_inet_addr_cmp(&addr, &ct->tuplehash[!dir].tuple.src.u3)) { | |
223 | buflen = sip_sprintf_addr(ct, buffer, | |
224 | &ct->tuplehash[!dir].tuple.src.u3, | |
225 | false); | |
051966c0 | 226 | if (!mangle_packet(skb, protoff, dataoff, dptr, datalen, |
3b6b9fab | 227 | poff, plen, buffer, buflen)) |
720ac708 PM |
228 | return NF_DROP; |
229 | } | |
230 | ||
231 | /* The rport= parameter (RFC 3581) contains the port number | |
232 | * from which the server received the request. */ | |
233 | if (ct_sip_parse_numerical_param(ct, *dptr, matchend, *datalen, | |
234 | "rport=", &poff, &plen, | |
235 | &n) > 0 && | |
236 | htons(n) == ct->tuplehash[dir].tuple.dst.u.udp.port && | |
237 | htons(n) != ct->tuplehash[!dir].tuple.src.u.udp.port) { | |
238 | __be16 p = ct->tuplehash[!dir].tuple.src.u.udp.port; | |
239 | buflen = sprintf(buffer, "%u", ntohs(p)); | |
051966c0 | 240 | if (!mangle_packet(skb, protoff, dataoff, dptr, datalen, |
3b6b9fab | 241 | poff, plen, buffer, buflen)) |
720ac708 PM |
242 | return NF_DROP; |
243 | } | |
9fafcd7b PM |
244 | } |
245 | ||
720ac708 | 246 | next: |
c978cd3a | 247 | /* Translate Contact headers */ |
3b6b9fab | 248 | coff = 0; |
c978cd3a | 249 | in_header = 0; |
3b6b9fab | 250 | while (ct_sip_parse_header_uri(ct, *dptr, &coff, *datalen, |
c978cd3a PM |
251 | SIP_HDR_CONTACT, &in_header, |
252 | &matchoff, &matchlen, | |
253 | &addr, &port) > 0) { | |
051966c0 PM |
254 | if (!map_addr(skb, protoff, dataoff, dptr, datalen, |
255 | matchoff, matchlen, | |
c978cd3a PM |
256 | &addr, port)) |
257 | return NF_DROP; | |
258 | } | |
259 | ||
051966c0 PM |
260 | if (!map_sip_addr(skb, protoff, dataoff, dptr, datalen, SIP_HDR_FROM) || |
261 | !map_sip_addr(skb, protoff, dataoff, dptr, datalen, SIP_HDR_TO)) | |
9fafcd7b | 262 | return NF_DROP; |
48f8ac26 | 263 | |
7266507d KC |
264 | /* Mangle destination port for Cisco phones, then fix up checksums */ |
265 | if (dir == IP_CT_DIR_REPLY && ct_sip_info->forced_dport) { | |
266 | struct udphdr *uh; | |
267 | ||
268 | if (!skb_make_writable(skb, skb->len)) | |
269 | return NF_DROP; | |
270 | ||
271 | uh = (void *)skb->data + protoff; | |
272 | uh->dest = ct_sip_info->forced_dport; | |
273 | ||
274 | if (!nf_nat_mangle_udp_packet(skb, ct, ctinfo, protoff, | |
275 | 0, 0, NULL, 0)) | |
276 | return NF_DROP; | |
277 | } | |
278 | ||
9fafcd7b PM |
279 | return NF_ACCEPT; |
280 | } | |
281 | ||
9a664821 PM |
282 | static void nf_nat_sip_seq_adjust(struct sk_buff *skb, unsigned int protoff, |
283 | s16 off) | |
48f8ac26 PM |
284 | { |
285 | enum ip_conntrack_info ctinfo; | |
286 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
287 | const struct tcphdr *th; | |
288 | ||
289 | if (nf_ct_protonum(ct) != IPPROTO_TCP || off == 0) | |
290 | return; | |
291 | ||
9a664821 | 292 | th = (struct tcphdr *)(skb->data + protoff); |
48f8ac26 PM |
293 | nf_nat_set_seq_adjust(ct, ctinfo, th->seq, off); |
294 | } | |
295 | ||
0f32a40f | 296 | /* Handles expected signalling connections and media streams */ |
9a664821 | 297 | static void nf_nat_sip_expected(struct nf_conn *ct, |
0f32a40f PM |
298 | struct nf_conntrack_expect *exp) |
299 | { | |
c7232c99 | 300 | struct nf_nat_range range; |
0f32a40f PM |
301 | |
302 | /* This must be a fresh one. */ | |
303 | BUG_ON(ct->status & IPS_NAT_DONE_MASK); | |
304 | ||
305 | /* For DST manip, map port here to where it's expected. */ | |
cbc9f2f4 | 306 | range.flags = (NF_NAT_RANGE_MAP_IPS | NF_NAT_RANGE_PROTO_SPECIFIED); |
c7232c99 PM |
307 | range.min_proto = range.max_proto = exp->saved_proto; |
308 | range.min_addr = range.max_addr = exp->saved_addr; | |
cbc9f2f4 | 309 | nf_nat_setup_info(ct, &range, NF_NAT_MANIP_DST); |
0f32a40f PM |
310 | |
311 | /* Change src to where master sends to, but only if the connection | |
312 | * actually came from the same source. */ | |
9a664821 PM |
313 | if (nf_inet_addr_cmp(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3, |
314 | &ct->master->tuplehash[exp->dir].tuple.src.u3)) { | |
cbc9f2f4 | 315 | range.flags = NF_NAT_RANGE_MAP_IPS; |
c7232c99 PM |
316 | range.min_addr = range.max_addr |
317 | = ct->master->tuplehash[!exp->dir].tuple.dst.u3; | |
cbc9f2f4 | 318 | nf_nat_setup_info(ct, &range, NF_NAT_MANIP_SRC); |
0f32a40f PM |
319 | } |
320 | } | |
321 | ||
9a664821 | 322 | static unsigned int nf_nat_sip_expect(struct sk_buff *skb, unsigned int protoff, |
051966c0 | 323 | unsigned int dataoff, |
0f32a40f PM |
324 | const char **dptr, unsigned int *datalen, |
325 | struct nf_conntrack_expect *exp, | |
326 | unsigned int matchoff, | |
327 | unsigned int matchlen) | |
328 | { | |
329 | enum ip_conntrack_info ctinfo; | |
330 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
331 | enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); | |
7266507d | 332 | struct nf_ct_sip_master *ct_sip_info = nfct_help_data(ct); |
9a664821 | 333 | union nf_inet_addr newaddr; |
0f32a40f | 334 | u_int16_t port; |
7266507d | 335 | __be16 srcport; |
9a664821 | 336 | char buffer[INET6_ADDRSTRLEN + sizeof("[]:nnnnn")]; |
95c96174 | 337 | unsigned int buflen; |
0f32a40f PM |
338 | |
339 | /* Connection will come from reply */ | |
9a664821 PM |
340 | if (nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.src.u3, |
341 | &ct->tuplehash[!dir].tuple.dst.u3)) | |
342 | newaddr = exp->tuple.dst.u3; | |
0f32a40f | 343 | else |
9a664821 | 344 | newaddr = ct->tuplehash[!dir].tuple.dst.u3; |
0f32a40f PM |
345 | |
346 | /* If the signalling port matches the connection's source port in the | |
347 | * original direction, try to use the destination port in the opposite | |
348 | * direction. */ | |
7266507d KC |
349 | srcport = ct_sip_info->forced_dport ? : |
350 | ct->tuplehash[dir].tuple.src.u.udp.port; | |
351 | if (exp->tuple.dst.u.udp.port == srcport) | |
0f32a40f PM |
352 | port = ntohs(ct->tuplehash[!dir].tuple.dst.u.udp.port); |
353 | else | |
354 | port = ntohs(exp->tuple.dst.u.udp.port); | |
355 | ||
c7232c99 | 356 | exp->saved_addr = exp->tuple.dst.u3; |
9a664821 | 357 | exp->tuple.dst.u3 = newaddr; |
0f32a40f PM |
358 | exp->saved_proto.udp.port = exp->tuple.dst.u.udp.port; |
359 | exp->dir = !dir; | |
9a664821 | 360 | exp->expectfn = nf_nat_sip_expected; |
0f32a40f PM |
361 | |
362 | for (; port != 0; port++) { | |
5b92b61f PNA |
363 | int ret; |
364 | ||
0f32a40f | 365 | exp->tuple.dst.u.udp.port = htons(port); |
5b92b61f PNA |
366 | ret = nf_ct_expect_related(exp); |
367 | if (ret == 0) | |
368 | break; | |
369 | else if (ret != -EBUSY) { | |
370 | port = 0; | |
0f32a40f | 371 | break; |
5b92b61f | 372 | } |
0f32a40f PM |
373 | } |
374 | ||
375 | if (port == 0) | |
376 | return NF_DROP; | |
377 | ||
9a664821 | 378 | if (!nf_inet_addr_cmp(&exp->tuple.dst.u3, &exp->saved_addr) || |
0f32a40f | 379 | exp->tuple.dst.u.udp.port != exp->saved_proto.udp.port) { |
9a664821 | 380 | buflen = sip_sprintf_addr_port(ct, buffer, &newaddr, port); |
051966c0 | 381 | if (!mangle_packet(skb, protoff, dataoff, dptr, datalen, |
3b6b9fab | 382 | matchoff, matchlen, buffer, buflen)) |
0f32a40f PM |
383 | goto err; |
384 | } | |
385 | return NF_ACCEPT; | |
386 | ||
387 | err: | |
388 | nf_ct_unexpect_related(exp); | |
389 | return NF_DROP; | |
390 | } | |
391 | ||
051966c0 PM |
392 | static int mangle_content_len(struct sk_buff *skb, unsigned int protoff, |
393 | unsigned int dataoff, | |
3e9b4600 | 394 | const char **dptr, unsigned int *datalen) |
9fafcd7b | 395 | { |
212440a7 PM |
396 | enum ip_conntrack_info ctinfo; |
397 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
3e9b4600 PM |
398 | unsigned int matchoff, matchlen; |
399 | char buffer[sizeof("65536")]; | |
400 | int buflen, c_len; | |
9fafcd7b | 401 | |
3e9b4600 PM |
402 | /* Get actual SDP length */ |
403 | if (ct_sip_get_sdp_header(ct, *dptr, 0, *datalen, | |
404 | SDP_HDR_VERSION, SDP_HDR_UNSPEC, | |
405 | &matchoff, &matchlen) <= 0) | |
406 | return 0; | |
407 | c_len = *datalen - matchoff + strlen("v="); | |
408 | ||
409 | /* Now, update SDP length */ | |
ea45f12a PM |
410 | if (ct_sip_get_header(ct, *dptr, 0, *datalen, SIP_HDR_CONTENT_LENGTH, |
411 | &matchoff, &matchlen) <= 0) | |
9fafcd7b PM |
412 | return 0; |
413 | ||
3e9b4600 | 414 | buflen = sprintf(buffer, "%u", c_len); |
051966c0 PM |
415 | return mangle_packet(skb, protoff, dataoff, dptr, datalen, |
416 | matchoff, matchlen, buffer, buflen); | |
9fafcd7b PM |
417 | } |
418 | ||
051966c0 PM |
419 | static int mangle_sdp_packet(struct sk_buff *skb, unsigned int protoff, |
420 | unsigned int dataoff, | |
3b6b9fab PM |
421 | const char **dptr, unsigned int *datalen, |
422 | unsigned int sdpoff, | |
c71529e4 HX |
423 | enum sdp_header_types type, |
424 | enum sdp_header_types term, | |
425 | char *buffer, int buflen) | |
9fafcd7b | 426 | { |
212440a7 PM |
427 | enum ip_conntrack_info ctinfo; |
428 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
3e9b4600 | 429 | unsigned int matchlen, matchoff; |
9fafcd7b | 430 | |
3b6b9fab | 431 | if (ct_sip_get_sdp_header(ct, *dptr, sdpoff, *datalen, type, term, |
3e9b4600 | 432 | &matchoff, &matchlen) <= 0) |
c71529e4 | 433 | return -ENOENT; |
051966c0 PM |
434 | return mangle_packet(skb, protoff, dataoff, dptr, datalen, |
435 | matchoff, matchlen, buffer, buflen) ? 0 : -EINVAL; | |
9fafcd7b PM |
436 | } |
437 | ||
9a664821 | 438 | static unsigned int nf_nat_sdp_addr(struct sk_buff *skb, unsigned int protoff, |
051966c0 | 439 | unsigned int dataoff, |
3b6b9fab PM |
440 | const char **dptr, unsigned int *datalen, |
441 | unsigned int sdpoff, | |
4ab9e64e PM |
442 | enum sdp_header_types type, |
443 | enum sdp_header_types term, | |
444 | const union nf_inet_addr *addr) | |
9fafcd7b | 445 | { |
9a664821 PM |
446 | enum ip_conntrack_info ctinfo; |
447 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
448 | char buffer[INET6_ADDRSTRLEN]; | |
4ab9e64e | 449 | unsigned int buflen; |
9fafcd7b | 450 | |
9a664821 | 451 | buflen = sip_sprintf_addr(ct, buffer, addr, false); |
051966c0 PM |
452 | if (mangle_sdp_packet(skb, protoff, dataoff, dptr, datalen, |
453 | sdpoff, type, term, buffer, buflen)) | |
9fafcd7b PM |
454 | return 0; |
455 | ||
051966c0 | 456 | return mangle_content_len(skb, protoff, dataoff, dptr, datalen); |
4ab9e64e PM |
457 | } |
458 | ||
9a664821 | 459 | static unsigned int nf_nat_sdp_port(struct sk_buff *skb, unsigned int protoff, |
051966c0 | 460 | unsigned int dataoff, |
3b6b9fab | 461 | const char **dptr, unsigned int *datalen, |
4ab9e64e PM |
462 | unsigned int matchoff, |
463 | unsigned int matchlen, | |
464 | u_int16_t port) | |
465 | { | |
466 | char buffer[sizeof("nnnnn")]; | |
467 | unsigned int buflen; | |
468 | ||
469 | buflen = sprintf(buffer, "%u", port); | |
051966c0 PM |
470 | if (!mangle_packet(skb, protoff, dataoff, dptr, datalen, |
471 | matchoff, matchlen, buffer, buflen)) | |
9fafcd7b PM |
472 | return 0; |
473 | ||
051966c0 | 474 | return mangle_content_len(skb, protoff, dataoff, dptr, datalen); |
4ab9e64e PM |
475 | } |
476 | ||
9a664821 | 477 | static unsigned int nf_nat_sdp_session(struct sk_buff *skb, unsigned int protoff, |
051966c0 | 478 | unsigned int dataoff, |
3b6b9fab PM |
479 | const char **dptr, unsigned int *datalen, |
480 | unsigned int sdpoff, | |
4ab9e64e PM |
481 | const union nf_inet_addr *addr) |
482 | { | |
9a664821 PM |
483 | enum ip_conntrack_info ctinfo; |
484 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
485 | char buffer[INET6_ADDRSTRLEN]; | |
4ab9e64e PM |
486 | unsigned int buflen; |
487 | ||
488 | /* Mangle session description owner and contact addresses */ | |
9a664821 | 489 | buflen = sip_sprintf_addr(ct, buffer, addr, false); |
051966c0 | 490 | if (mangle_sdp_packet(skb, protoff, dataoff, dptr, datalen, sdpoff, |
9a664821 | 491 | SDP_HDR_OWNER, SDP_HDR_MEDIA, buffer, buflen)) |
4ab9e64e PM |
492 | return 0; |
493 | ||
051966c0 | 494 | switch (mangle_sdp_packet(skb, protoff, dataoff, dptr, datalen, sdpoff, |
9a664821 | 495 | SDP_HDR_CONNECTION, SDP_HDR_MEDIA, |
c71529e4 HX |
496 | buffer, buflen)) { |
497 | case 0: | |
498 | /* | |
499 | * RFC 2327: | |
500 | * | |
501 | * Session description | |
502 | * | |
503 | * c=* (connection information - not required if included in all media) | |
504 | */ | |
505 | case -ENOENT: | |
506 | break; | |
507 | default: | |
9fafcd7b | 508 | return 0; |
c71529e4 | 509 | } |
9fafcd7b | 510 | |
051966c0 | 511 | return mangle_content_len(skb, protoff, dataoff, dptr, datalen); |
9fafcd7b PM |
512 | } |
513 | ||
514 | /* So, this packet has hit the connection tracking matching code. | |
515 | Mangle it, and change the expectation to match the new version. */ | |
9a664821 | 516 | static unsigned int nf_nat_sdp_media(struct sk_buff *skb, unsigned int protoff, |
051966c0 | 517 | unsigned int dataoff, |
3b6b9fab | 518 | const char **dptr, unsigned int *datalen, |
4ab9e64e PM |
519 | struct nf_conntrack_expect *rtp_exp, |
520 | struct nf_conntrack_expect *rtcp_exp, | |
521 | unsigned int mediaoff, | |
522 | unsigned int medialen, | |
523 | union nf_inet_addr *rtp_addr) | |
9fafcd7b | 524 | { |
212440a7 PM |
525 | enum ip_conntrack_info ctinfo; |
526 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
9fafcd7b | 527 | enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); |
9fafcd7b PM |
528 | u_int16_t port; |
529 | ||
9fafcd7b | 530 | /* Connection will come from reply */ |
9a664821 PM |
531 | if (nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.src.u3, |
532 | &ct->tuplehash[!dir].tuple.dst.u3)) | |
533 | *rtp_addr = rtp_exp->tuple.dst.u3; | |
f4a607bf | 534 | else |
9a664821 | 535 | *rtp_addr = ct->tuplehash[!dir].tuple.dst.u3; |
9fafcd7b | 536 | |
c7232c99 | 537 | rtp_exp->saved_addr = rtp_exp->tuple.dst.u3; |
9a664821 | 538 | rtp_exp->tuple.dst.u3 = *rtp_addr; |
a9c1d359 PM |
539 | rtp_exp->saved_proto.udp.port = rtp_exp->tuple.dst.u.udp.port; |
540 | rtp_exp->dir = !dir; | |
9a664821 | 541 | rtp_exp->expectfn = nf_nat_sip_expected; |
a9c1d359 | 542 | |
c7232c99 | 543 | rtcp_exp->saved_addr = rtcp_exp->tuple.dst.u3; |
9a664821 | 544 | rtcp_exp->tuple.dst.u3 = *rtp_addr; |
a9c1d359 PM |
545 | rtcp_exp->saved_proto.udp.port = rtcp_exp->tuple.dst.u.udp.port; |
546 | rtcp_exp->dir = !dir; | |
9a664821 | 547 | rtcp_exp->expectfn = nf_nat_sip_expected; |
a9c1d359 PM |
548 | |
549 | /* Try to get same pair of ports: if not, try to change them. */ | |
550 | for (port = ntohs(rtp_exp->tuple.dst.u.udp.port); | |
551 | port != 0; port += 2) { | |
5b92b61f PNA |
552 | int ret; |
553 | ||
a9c1d359 | 554 | rtp_exp->tuple.dst.u.udp.port = htons(port); |
5b92b61f PNA |
555 | ret = nf_ct_expect_related(rtp_exp); |
556 | if (ret == -EBUSY) | |
a9c1d359 | 557 | continue; |
5b92b61f PNA |
558 | else if (ret < 0) { |
559 | port = 0; | |
560 | break; | |
561 | } | |
a9c1d359 | 562 | rtcp_exp->tuple.dst.u.udp.port = htons(port + 1); |
5b92b61f PNA |
563 | ret = nf_ct_expect_related(rtcp_exp); |
564 | if (ret == 0) | |
9fafcd7b | 565 | break; |
3f509c68 PNA |
566 | else if (ret == -EBUSY) { |
567 | nf_ct_unexpect_related(rtp_exp); | |
568 | continue; | |
569 | } else if (ret < 0) { | |
5b92b61f PNA |
570 | nf_ct_unexpect_related(rtp_exp); |
571 | port = 0; | |
572 | break; | |
573 | } | |
9fafcd7b PM |
574 | } |
575 | ||
576 | if (port == 0) | |
4ab9e64e PM |
577 | goto err1; |
578 | ||
579 | /* Update media port. */ | |
580 | if (rtp_exp->tuple.dst.u.udp.port != rtp_exp->saved_proto.udp.port && | |
9a664821 | 581 | !nf_nat_sdp_port(skb, protoff, dataoff, dptr, datalen, |
3b6b9fab | 582 | mediaoff, medialen, port)) |
4ab9e64e | 583 | goto err2; |
9fafcd7b | 584 | |
9fafcd7b | 585 | return NF_ACCEPT; |
4ab9e64e PM |
586 | |
587 | err2: | |
588 | nf_ct_unexpect_related(rtp_exp); | |
589 | nf_ct_unexpect_related(rtcp_exp); | |
590 | err1: | |
591 | return NF_DROP; | |
9fafcd7b PM |
592 | } |
593 | ||
544d5c7d | 594 | static struct nf_ct_helper_expectfn sip_nat = { |
9a664821 PM |
595 | .name = "sip", |
596 | .expectfn = nf_nat_sip_expected, | |
544d5c7d PNA |
597 | }; |
598 | ||
9fafcd7b PM |
599 | static void __exit nf_nat_sip_fini(void) |
600 | { | |
a9b3cd7f SH |
601 | RCU_INIT_POINTER(nf_nat_sip_hook, NULL); |
602 | RCU_INIT_POINTER(nf_nat_sip_seq_adjust_hook, NULL); | |
603 | RCU_INIT_POINTER(nf_nat_sip_expect_hook, NULL); | |
604 | RCU_INIT_POINTER(nf_nat_sdp_addr_hook, NULL); | |
605 | RCU_INIT_POINTER(nf_nat_sdp_port_hook, NULL); | |
606 | RCU_INIT_POINTER(nf_nat_sdp_session_hook, NULL); | |
607 | RCU_INIT_POINTER(nf_nat_sdp_media_hook, NULL); | |
544d5c7d | 608 | nf_ct_helper_expectfn_unregister(&sip_nat); |
9fafcd7b PM |
609 | synchronize_rcu(); |
610 | } | |
611 | ||
612 | static int __init nf_nat_sip_init(void) | |
613 | { | |
d1332e0a | 614 | BUG_ON(nf_nat_sip_hook != NULL); |
48f8ac26 | 615 | BUG_ON(nf_nat_sip_seq_adjust_hook != NULL); |
0f32a40f | 616 | BUG_ON(nf_nat_sip_expect_hook != NULL); |
4ab9e64e | 617 | BUG_ON(nf_nat_sdp_addr_hook != NULL); |
c7f485ab | 618 | BUG_ON(nf_nat_sdp_port_hook != NULL); |
4ab9e64e PM |
619 | BUG_ON(nf_nat_sdp_session_hook != NULL); |
620 | BUG_ON(nf_nat_sdp_media_hook != NULL); | |
9a664821 PM |
621 | RCU_INIT_POINTER(nf_nat_sip_hook, nf_nat_sip); |
622 | RCU_INIT_POINTER(nf_nat_sip_seq_adjust_hook, nf_nat_sip_seq_adjust); | |
623 | RCU_INIT_POINTER(nf_nat_sip_expect_hook, nf_nat_sip_expect); | |
624 | RCU_INIT_POINTER(nf_nat_sdp_addr_hook, nf_nat_sdp_addr); | |
625 | RCU_INIT_POINTER(nf_nat_sdp_port_hook, nf_nat_sdp_port); | |
626 | RCU_INIT_POINTER(nf_nat_sdp_session_hook, nf_nat_sdp_session); | |
627 | RCU_INIT_POINTER(nf_nat_sdp_media_hook, nf_nat_sdp_media); | |
544d5c7d | 628 | nf_ct_helper_expectfn_register(&sip_nat); |
9fafcd7b PM |
629 | return 0; |
630 | } | |
631 | ||
632 | module_init(nf_nat_sip_init); | |
633 | module_exit(nf_nat_sip_fini); |