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 | 161 | !map_addr(skb, protoff, dataoff, dptr, datalen, |
b20ab9cc PNA |
162 | matchoff, matchlen, &addr, port)) { |
163 | nf_ct_helper_log(skb, ct, "cannot mangle SIP message"); | |
9fafcd7b | 164 | return NF_DROP; |
b20ab9cc | 165 | } |
720ac708 PM |
166 | request = 1; |
167 | } else | |
168 | request = 0; | |
169 | ||
48f8ac26 PM |
170 | if (nf_ct_protonum(ct) == IPPROTO_TCP) |
171 | hdr = SIP_HDR_VIA_TCP; | |
172 | else | |
173 | hdr = SIP_HDR_VIA_UDP; | |
174 | ||
720ac708 PM |
175 | /* Translate topmost Via header and parameters */ |
176 | if (ct_sip_parse_header_uri(ct, *dptr, NULL, *datalen, | |
48f8ac26 | 177 | hdr, NULL, &matchoff, &matchlen, |
720ac708 | 178 | &addr, &port) > 0) { |
f22eb25c | 179 | unsigned int olen, matchend, poff, plen, buflen, n; |
9a664821 | 180 | char buffer[INET6_ADDRSTRLEN + sizeof("[]:nnnnn")]; |
720ac708 PM |
181 | |
182 | /* We're only interested in headers related to this | |
183 | * connection */ | |
184 | if (request) { | |
9a664821 PM |
185 | if (!nf_inet_addr_cmp(&addr, |
186 | &ct->tuplehash[dir].tuple.src.u3) || | |
720ac708 PM |
187 | port != ct->tuplehash[dir].tuple.src.u.udp.port) |
188 | goto next; | |
189 | } else { | |
9a664821 PM |
190 | if (!nf_inet_addr_cmp(&addr, |
191 | &ct->tuplehash[dir].tuple.dst.u3) || | |
720ac708 PM |
192 | port != ct->tuplehash[dir].tuple.dst.u.udp.port) |
193 | goto next; | |
194 | } | |
195 | ||
f22eb25c | 196 | olen = *datalen; |
051966c0 | 197 | if (!map_addr(skb, protoff, dataoff, dptr, datalen, |
b20ab9cc PNA |
198 | matchoff, matchlen, &addr, port)) { |
199 | nf_ct_helper_log(skb, ct, "cannot mangle Via header"); | |
720ac708 | 200 | return NF_DROP; |
b20ab9cc | 201 | } |
720ac708 | 202 | |
f22eb25c | 203 | matchend = matchoff + matchlen + *datalen - olen; |
720ac708 PM |
204 | |
205 | /* The maddr= parameter (RFC 2361) specifies where to send | |
206 | * the reply. */ | |
207 | if (ct_sip_parse_address_param(ct, *dptr, matchend, *datalen, | |
208 | "maddr=", &poff, &plen, | |
02b69cbd | 209 | &addr, true) > 0 && |
9a664821 PM |
210 | nf_inet_addr_cmp(&addr, &ct->tuplehash[dir].tuple.src.u3) && |
211 | !nf_inet_addr_cmp(&addr, &ct->tuplehash[!dir].tuple.dst.u3)) { | |
212 | buflen = sip_sprintf_addr(ct, buffer, | |
213 | &ct->tuplehash[!dir].tuple.dst.u3, | |
214 | true); | |
051966c0 | 215 | if (!mangle_packet(skb, protoff, dataoff, dptr, datalen, |
b20ab9cc PNA |
216 | poff, plen, buffer, buflen)) { |
217 | nf_ct_helper_log(skb, ct, "cannot mangle maddr"); | |
720ac708 | 218 | return NF_DROP; |
b20ab9cc | 219 | } |
720ac708 PM |
220 | } |
221 | ||
222 | /* The received= parameter (RFC 2361) contains the address | |
223 | * from which the server received the request. */ | |
224 | if (ct_sip_parse_address_param(ct, *dptr, matchend, *datalen, | |
225 | "received=", &poff, &plen, | |
02b69cbd | 226 | &addr, false) > 0 && |
9a664821 PM |
227 | nf_inet_addr_cmp(&addr, &ct->tuplehash[dir].tuple.dst.u3) && |
228 | !nf_inet_addr_cmp(&addr, &ct->tuplehash[!dir].tuple.src.u3)) { | |
229 | buflen = sip_sprintf_addr(ct, buffer, | |
230 | &ct->tuplehash[!dir].tuple.src.u3, | |
231 | false); | |
051966c0 | 232 | if (!mangle_packet(skb, protoff, dataoff, dptr, datalen, |
3b6b9fab | 233 | poff, plen, buffer, buflen)) |
b20ab9cc | 234 | nf_ct_helper_log(skb, ct, "cannot mangle received"); |
720ac708 PM |
235 | return NF_DROP; |
236 | } | |
237 | ||
238 | /* The rport= parameter (RFC 3581) contains the port number | |
239 | * from which the server received the request. */ | |
240 | if (ct_sip_parse_numerical_param(ct, *dptr, matchend, *datalen, | |
241 | "rport=", &poff, &plen, | |
242 | &n) > 0 && | |
243 | htons(n) == ct->tuplehash[dir].tuple.dst.u.udp.port && | |
244 | htons(n) != ct->tuplehash[!dir].tuple.src.u.udp.port) { | |
245 | __be16 p = ct->tuplehash[!dir].tuple.src.u.udp.port; | |
246 | buflen = sprintf(buffer, "%u", ntohs(p)); | |
051966c0 | 247 | if (!mangle_packet(skb, protoff, dataoff, dptr, datalen, |
b20ab9cc PNA |
248 | poff, plen, buffer, buflen)) { |
249 | nf_ct_helper_log(skb, ct, "cannot mangle rport"); | |
720ac708 | 250 | return NF_DROP; |
b20ab9cc | 251 | } |
720ac708 | 252 | } |
9fafcd7b PM |
253 | } |
254 | ||
720ac708 | 255 | next: |
c978cd3a | 256 | /* Translate Contact headers */ |
3b6b9fab | 257 | coff = 0; |
c978cd3a | 258 | in_header = 0; |
3b6b9fab | 259 | while (ct_sip_parse_header_uri(ct, *dptr, &coff, *datalen, |
c978cd3a PM |
260 | SIP_HDR_CONTACT, &in_header, |
261 | &matchoff, &matchlen, | |
262 | &addr, &port) > 0) { | |
051966c0 PM |
263 | if (!map_addr(skb, protoff, dataoff, dptr, datalen, |
264 | matchoff, matchlen, | |
b20ab9cc PNA |
265 | &addr, port)) { |
266 | nf_ct_helper_log(skb, ct, "cannot mangle contact"); | |
c978cd3a | 267 | return NF_DROP; |
b20ab9cc | 268 | } |
c978cd3a PM |
269 | } |
270 | ||
051966c0 | 271 | if (!map_sip_addr(skb, protoff, dataoff, dptr, datalen, SIP_HDR_FROM) || |
b20ab9cc PNA |
272 | !map_sip_addr(skb, protoff, dataoff, dptr, datalen, SIP_HDR_TO)) { |
273 | nf_ct_helper_log(skb, ct, "cannot mangle SIP from/to"); | |
9fafcd7b | 274 | return NF_DROP; |
b20ab9cc | 275 | } |
48f8ac26 | 276 | |
7266507d KC |
277 | /* Mangle destination port for Cisco phones, then fix up checksums */ |
278 | if (dir == IP_CT_DIR_REPLY && ct_sip_info->forced_dport) { | |
279 | struct udphdr *uh; | |
280 | ||
b20ab9cc PNA |
281 | if (!skb_make_writable(skb, skb->len)) { |
282 | nf_ct_helper_log(skb, ct, "cannot mangle packet"); | |
7266507d | 283 | return NF_DROP; |
b20ab9cc | 284 | } |
7266507d KC |
285 | |
286 | uh = (void *)skb->data + protoff; | |
287 | uh->dest = ct_sip_info->forced_dport; | |
288 | ||
289 | if (!nf_nat_mangle_udp_packet(skb, ct, ctinfo, protoff, | |
b20ab9cc PNA |
290 | 0, 0, NULL, 0)) { |
291 | nf_ct_helper_log(skb, ct, "cannot mangle packet"); | |
7266507d | 292 | return NF_DROP; |
b20ab9cc | 293 | } |
7266507d KC |
294 | } |
295 | ||
9fafcd7b PM |
296 | return NF_ACCEPT; |
297 | } | |
298 | ||
9a664821 PM |
299 | static void nf_nat_sip_seq_adjust(struct sk_buff *skb, unsigned int protoff, |
300 | s16 off) | |
48f8ac26 PM |
301 | { |
302 | enum ip_conntrack_info ctinfo; | |
303 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
304 | const struct tcphdr *th; | |
305 | ||
306 | if (nf_ct_protonum(ct) != IPPROTO_TCP || off == 0) | |
307 | return; | |
308 | ||
9a664821 | 309 | th = (struct tcphdr *)(skb->data + protoff); |
48f8ac26 PM |
310 | nf_nat_set_seq_adjust(ct, ctinfo, th->seq, off); |
311 | } | |
312 | ||
0f32a40f | 313 | /* Handles expected signalling connections and media streams */ |
9a664821 | 314 | static void nf_nat_sip_expected(struct nf_conn *ct, |
0f32a40f PM |
315 | struct nf_conntrack_expect *exp) |
316 | { | |
c7232c99 | 317 | struct nf_nat_range range; |
0f32a40f PM |
318 | |
319 | /* This must be a fresh one. */ | |
320 | BUG_ON(ct->status & IPS_NAT_DONE_MASK); | |
321 | ||
322 | /* For DST manip, map port here to where it's expected. */ | |
cbc9f2f4 | 323 | range.flags = (NF_NAT_RANGE_MAP_IPS | NF_NAT_RANGE_PROTO_SPECIFIED); |
c7232c99 PM |
324 | range.min_proto = range.max_proto = exp->saved_proto; |
325 | range.min_addr = range.max_addr = exp->saved_addr; | |
cbc9f2f4 | 326 | nf_nat_setup_info(ct, &range, NF_NAT_MANIP_DST); |
0f32a40f PM |
327 | |
328 | /* Change src to where master sends to, but only if the connection | |
329 | * actually came from the same source. */ | |
9a664821 PM |
330 | if (nf_inet_addr_cmp(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3, |
331 | &ct->master->tuplehash[exp->dir].tuple.src.u3)) { | |
cbc9f2f4 | 332 | range.flags = NF_NAT_RANGE_MAP_IPS; |
c7232c99 PM |
333 | range.min_addr = range.max_addr |
334 | = ct->master->tuplehash[!exp->dir].tuple.dst.u3; | |
cbc9f2f4 | 335 | nf_nat_setup_info(ct, &range, NF_NAT_MANIP_SRC); |
0f32a40f PM |
336 | } |
337 | } | |
338 | ||
9a664821 | 339 | static unsigned int nf_nat_sip_expect(struct sk_buff *skb, unsigned int protoff, |
051966c0 | 340 | unsigned int dataoff, |
0f32a40f PM |
341 | const char **dptr, unsigned int *datalen, |
342 | struct nf_conntrack_expect *exp, | |
343 | unsigned int matchoff, | |
344 | unsigned int matchlen) | |
345 | { | |
346 | enum ip_conntrack_info ctinfo; | |
347 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
348 | enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); | |
7266507d | 349 | struct nf_ct_sip_master *ct_sip_info = nfct_help_data(ct); |
9a664821 | 350 | union nf_inet_addr newaddr; |
0f32a40f | 351 | u_int16_t port; |
7266507d | 352 | __be16 srcport; |
9a664821 | 353 | char buffer[INET6_ADDRSTRLEN + sizeof("[]:nnnnn")]; |
95c96174 | 354 | unsigned int buflen; |
0f32a40f PM |
355 | |
356 | /* Connection will come from reply */ | |
9a664821 PM |
357 | if (nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.src.u3, |
358 | &ct->tuplehash[!dir].tuple.dst.u3)) | |
359 | newaddr = exp->tuple.dst.u3; | |
0f32a40f | 360 | else |
9a664821 | 361 | newaddr = ct->tuplehash[!dir].tuple.dst.u3; |
0f32a40f PM |
362 | |
363 | /* If the signalling port matches the connection's source port in the | |
364 | * original direction, try to use the destination port in the opposite | |
365 | * direction. */ | |
7266507d KC |
366 | srcport = ct_sip_info->forced_dport ? : |
367 | ct->tuplehash[dir].tuple.src.u.udp.port; | |
368 | if (exp->tuple.dst.u.udp.port == srcport) | |
0f32a40f PM |
369 | port = ntohs(ct->tuplehash[!dir].tuple.dst.u.udp.port); |
370 | else | |
371 | port = ntohs(exp->tuple.dst.u.udp.port); | |
372 | ||
c7232c99 | 373 | exp->saved_addr = exp->tuple.dst.u3; |
9a664821 | 374 | exp->tuple.dst.u3 = newaddr; |
0f32a40f PM |
375 | exp->saved_proto.udp.port = exp->tuple.dst.u.udp.port; |
376 | exp->dir = !dir; | |
9a664821 | 377 | exp->expectfn = nf_nat_sip_expected; |
0f32a40f PM |
378 | |
379 | for (; port != 0; port++) { | |
5b92b61f PNA |
380 | int ret; |
381 | ||
0f32a40f | 382 | exp->tuple.dst.u.udp.port = htons(port); |
5b92b61f PNA |
383 | ret = nf_ct_expect_related(exp); |
384 | if (ret == 0) | |
385 | break; | |
386 | else if (ret != -EBUSY) { | |
387 | port = 0; | |
0f32a40f | 388 | break; |
5b92b61f | 389 | } |
0f32a40f PM |
390 | } |
391 | ||
b20ab9cc PNA |
392 | if (port == 0) { |
393 | nf_ct_helper_log(skb, ct, "all ports in use for SIP"); | |
0f32a40f | 394 | return NF_DROP; |
b20ab9cc | 395 | } |
0f32a40f | 396 | |
9a664821 | 397 | if (!nf_inet_addr_cmp(&exp->tuple.dst.u3, &exp->saved_addr) || |
0f32a40f | 398 | exp->tuple.dst.u.udp.port != exp->saved_proto.udp.port) { |
9a664821 | 399 | buflen = sip_sprintf_addr_port(ct, buffer, &newaddr, port); |
051966c0 | 400 | if (!mangle_packet(skb, protoff, dataoff, dptr, datalen, |
b20ab9cc PNA |
401 | matchoff, matchlen, buffer, buflen)) { |
402 | nf_ct_helper_log(skb, ct, "cannot mangle packet"); | |
0f32a40f | 403 | goto err; |
b20ab9cc | 404 | } |
0f32a40f PM |
405 | } |
406 | return NF_ACCEPT; | |
407 | ||
408 | err: | |
409 | nf_ct_unexpect_related(exp); | |
410 | return NF_DROP; | |
411 | } | |
412 | ||
051966c0 PM |
413 | static int mangle_content_len(struct sk_buff *skb, unsigned int protoff, |
414 | unsigned int dataoff, | |
3e9b4600 | 415 | const char **dptr, unsigned int *datalen) |
9fafcd7b | 416 | { |
212440a7 PM |
417 | enum ip_conntrack_info ctinfo; |
418 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
3e9b4600 PM |
419 | unsigned int matchoff, matchlen; |
420 | char buffer[sizeof("65536")]; | |
421 | int buflen, c_len; | |
9fafcd7b | 422 | |
3e9b4600 PM |
423 | /* Get actual SDP length */ |
424 | if (ct_sip_get_sdp_header(ct, *dptr, 0, *datalen, | |
425 | SDP_HDR_VERSION, SDP_HDR_UNSPEC, | |
426 | &matchoff, &matchlen) <= 0) | |
427 | return 0; | |
428 | c_len = *datalen - matchoff + strlen("v="); | |
429 | ||
430 | /* Now, update SDP length */ | |
ea45f12a PM |
431 | if (ct_sip_get_header(ct, *dptr, 0, *datalen, SIP_HDR_CONTENT_LENGTH, |
432 | &matchoff, &matchlen) <= 0) | |
9fafcd7b PM |
433 | return 0; |
434 | ||
3e9b4600 | 435 | buflen = sprintf(buffer, "%u", c_len); |
051966c0 PM |
436 | return mangle_packet(skb, protoff, dataoff, dptr, datalen, |
437 | matchoff, matchlen, buffer, buflen); | |
9fafcd7b PM |
438 | } |
439 | ||
051966c0 PM |
440 | static int mangle_sdp_packet(struct sk_buff *skb, unsigned int protoff, |
441 | unsigned int dataoff, | |
3b6b9fab PM |
442 | const char **dptr, unsigned int *datalen, |
443 | unsigned int sdpoff, | |
c71529e4 HX |
444 | enum sdp_header_types type, |
445 | enum sdp_header_types term, | |
446 | char *buffer, int buflen) | |
9fafcd7b | 447 | { |
212440a7 PM |
448 | enum ip_conntrack_info ctinfo; |
449 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
3e9b4600 | 450 | unsigned int matchlen, matchoff; |
9fafcd7b | 451 | |
3b6b9fab | 452 | if (ct_sip_get_sdp_header(ct, *dptr, sdpoff, *datalen, type, term, |
3e9b4600 | 453 | &matchoff, &matchlen) <= 0) |
c71529e4 | 454 | return -ENOENT; |
051966c0 PM |
455 | return mangle_packet(skb, protoff, dataoff, dptr, datalen, |
456 | matchoff, matchlen, buffer, buflen) ? 0 : -EINVAL; | |
9fafcd7b PM |
457 | } |
458 | ||
9a664821 | 459 | static unsigned int nf_nat_sdp_addr(struct sk_buff *skb, unsigned int protoff, |
051966c0 | 460 | unsigned int dataoff, |
3b6b9fab PM |
461 | const char **dptr, unsigned int *datalen, |
462 | unsigned int sdpoff, | |
4ab9e64e PM |
463 | enum sdp_header_types type, |
464 | enum sdp_header_types term, | |
465 | const union nf_inet_addr *addr) | |
9fafcd7b | 466 | { |
9a664821 PM |
467 | enum ip_conntrack_info ctinfo; |
468 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
469 | char buffer[INET6_ADDRSTRLEN]; | |
4ab9e64e | 470 | unsigned int buflen; |
9fafcd7b | 471 | |
9a664821 | 472 | buflen = sip_sprintf_addr(ct, buffer, addr, false); |
051966c0 PM |
473 | if (mangle_sdp_packet(skb, protoff, dataoff, dptr, datalen, |
474 | sdpoff, type, term, buffer, buflen)) | |
9fafcd7b PM |
475 | return 0; |
476 | ||
051966c0 | 477 | return mangle_content_len(skb, protoff, dataoff, dptr, datalen); |
4ab9e64e PM |
478 | } |
479 | ||
9a664821 | 480 | static unsigned int nf_nat_sdp_port(struct sk_buff *skb, unsigned int protoff, |
051966c0 | 481 | unsigned int dataoff, |
3b6b9fab | 482 | const char **dptr, unsigned int *datalen, |
4ab9e64e PM |
483 | unsigned int matchoff, |
484 | unsigned int matchlen, | |
485 | u_int16_t port) | |
486 | { | |
487 | char buffer[sizeof("nnnnn")]; | |
488 | unsigned int buflen; | |
489 | ||
490 | buflen = sprintf(buffer, "%u", port); | |
051966c0 PM |
491 | if (!mangle_packet(skb, protoff, dataoff, dptr, datalen, |
492 | matchoff, matchlen, buffer, buflen)) | |
9fafcd7b PM |
493 | return 0; |
494 | ||
051966c0 | 495 | return mangle_content_len(skb, protoff, dataoff, dptr, datalen); |
4ab9e64e PM |
496 | } |
497 | ||
9a664821 | 498 | static unsigned int nf_nat_sdp_session(struct sk_buff *skb, unsigned int protoff, |
051966c0 | 499 | unsigned int dataoff, |
3b6b9fab PM |
500 | const char **dptr, unsigned int *datalen, |
501 | unsigned int sdpoff, | |
4ab9e64e PM |
502 | const union nf_inet_addr *addr) |
503 | { | |
9a664821 PM |
504 | enum ip_conntrack_info ctinfo; |
505 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
506 | char buffer[INET6_ADDRSTRLEN]; | |
4ab9e64e PM |
507 | unsigned int buflen; |
508 | ||
509 | /* Mangle session description owner and contact addresses */ | |
9a664821 | 510 | buflen = sip_sprintf_addr(ct, buffer, addr, false); |
051966c0 | 511 | if (mangle_sdp_packet(skb, protoff, dataoff, dptr, datalen, sdpoff, |
9a664821 | 512 | SDP_HDR_OWNER, SDP_HDR_MEDIA, buffer, buflen)) |
4ab9e64e PM |
513 | return 0; |
514 | ||
051966c0 | 515 | switch (mangle_sdp_packet(skb, protoff, dataoff, dptr, datalen, sdpoff, |
9a664821 | 516 | SDP_HDR_CONNECTION, SDP_HDR_MEDIA, |
c71529e4 HX |
517 | buffer, buflen)) { |
518 | case 0: | |
519 | /* | |
520 | * RFC 2327: | |
521 | * | |
522 | * Session description | |
523 | * | |
524 | * c=* (connection information - not required if included in all media) | |
525 | */ | |
526 | case -ENOENT: | |
527 | break; | |
528 | default: | |
9fafcd7b | 529 | return 0; |
c71529e4 | 530 | } |
9fafcd7b | 531 | |
051966c0 | 532 | return mangle_content_len(skb, protoff, dataoff, dptr, datalen); |
9fafcd7b PM |
533 | } |
534 | ||
535 | /* So, this packet has hit the connection tracking matching code. | |
536 | Mangle it, and change the expectation to match the new version. */ | |
9a664821 | 537 | static unsigned int nf_nat_sdp_media(struct sk_buff *skb, unsigned int protoff, |
051966c0 | 538 | unsigned int dataoff, |
3b6b9fab | 539 | const char **dptr, unsigned int *datalen, |
4ab9e64e PM |
540 | struct nf_conntrack_expect *rtp_exp, |
541 | struct nf_conntrack_expect *rtcp_exp, | |
542 | unsigned int mediaoff, | |
543 | unsigned int medialen, | |
544 | union nf_inet_addr *rtp_addr) | |
9fafcd7b | 545 | { |
212440a7 PM |
546 | enum ip_conntrack_info ctinfo; |
547 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
9fafcd7b | 548 | enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); |
9fafcd7b PM |
549 | u_int16_t port; |
550 | ||
9fafcd7b | 551 | /* Connection will come from reply */ |
9a664821 PM |
552 | if (nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.src.u3, |
553 | &ct->tuplehash[!dir].tuple.dst.u3)) | |
554 | *rtp_addr = rtp_exp->tuple.dst.u3; | |
f4a607bf | 555 | else |
9a664821 | 556 | *rtp_addr = ct->tuplehash[!dir].tuple.dst.u3; |
9fafcd7b | 557 | |
c7232c99 | 558 | rtp_exp->saved_addr = rtp_exp->tuple.dst.u3; |
9a664821 | 559 | rtp_exp->tuple.dst.u3 = *rtp_addr; |
a9c1d359 PM |
560 | rtp_exp->saved_proto.udp.port = rtp_exp->tuple.dst.u.udp.port; |
561 | rtp_exp->dir = !dir; | |
9a664821 | 562 | rtp_exp->expectfn = nf_nat_sip_expected; |
a9c1d359 | 563 | |
c7232c99 | 564 | rtcp_exp->saved_addr = rtcp_exp->tuple.dst.u3; |
9a664821 | 565 | rtcp_exp->tuple.dst.u3 = *rtp_addr; |
a9c1d359 PM |
566 | rtcp_exp->saved_proto.udp.port = rtcp_exp->tuple.dst.u.udp.port; |
567 | rtcp_exp->dir = !dir; | |
9a664821 | 568 | rtcp_exp->expectfn = nf_nat_sip_expected; |
a9c1d359 PM |
569 | |
570 | /* Try to get same pair of ports: if not, try to change them. */ | |
571 | for (port = ntohs(rtp_exp->tuple.dst.u.udp.port); | |
572 | port != 0; port += 2) { | |
5b92b61f PNA |
573 | int ret; |
574 | ||
a9c1d359 | 575 | rtp_exp->tuple.dst.u.udp.port = htons(port); |
5b92b61f PNA |
576 | ret = nf_ct_expect_related(rtp_exp); |
577 | if (ret == -EBUSY) | |
a9c1d359 | 578 | continue; |
5b92b61f PNA |
579 | else if (ret < 0) { |
580 | port = 0; | |
581 | break; | |
582 | } | |
a9c1d359 | 583 | rtcp_exp->tuple.dst.u.udp.port = htons(port + 1); |
5b92b61f PNA |
584 | ret = nf_ct_expect_related(rtcp_exp); |
585 | if (ret == 0) | |
9fafcd7b | 586 | break; |
3f509c68 PNA |
587 | else if (ret == -EBUSY) { |
588 | nf_ct_unexpect_related(rtp_exp); | |
589 | continue; | |
590 | } else if (ret < 0) { | |
5b92b61f PNA |
591 | nf_ct_unexpect_related(rtp_exp); |
592 | port = 0; | |
593 | break; | |
594 | } | |
9fafcd7b PM |
595 | } |
596 | ||
b20ab9cc PNA |
597 | if (port == 0) { |
598 | nf_ct_helper_log(skb, ct, "all ports in use for SDP media"); | |
4ab9e64e | 599 | goto err1; |
b20ab9cc | 600 | } |
4ab9e64e PM |
601 | |
602 | /* Update media port. */ | |
603 | if (rtp_exp->tuple.dst.u.udp.port != rtp_exp->saved_proto.udp.port && | |
9a664821 | 604 | !nf_nat_sdp_port(skb, protoff, dataoff, dptr, datalen, |
b20ab9cc PNA |
605 | mediaoff, medialen, port)) { |
606 | nf_ct_helper_log(skb, ct, "cannot mangle SDP message"); | |
4ab9e64e | 607 | goto err2; |
b20ab9cc | 608 | } |
9fafcd7b | 609 | |
9fafcd7b | 610 | return NF_ACCEPT; |
4ab9e64e PM |
611 | |
612 | err2: | |
613 | nf_ct_unexpect_related(rtp_exp); | |
614 | nf_ct_unexpect_related(rtcp_exp); | |
615 | err1: | |
616 | return NF_DROP; | |
9fafcd7b PM |
617 | } |
618 | ||
544d5c7d | 619 | static struct nf_ct_helper_expectfn sip_nat = { |
9a664821 PM |
620 | .name = "sip", |
621 | .expectfn = nf_nat_sip_expected, | |
544d5c7d PNA |
622 | }; |
623 | ||
9fafcd7b PM |
624 | static void __exit nf_nat_sip_fini(void) |
625 | { | |
a9b3cd7f SH |
626 | RCU_INIT_POINTER(nf_nat_sip_hook, NULL); |
627 | RCU_INIT_POINTER(nf_nat_sip_seq_adjust_hook, NULL); | |
628 | RCU_INIT_POINTER(nf_nat_sip_expect_hook, NULL); | |
629 | RCU_INIT_POINTER(nf_nat_sdp_addr_hook, NULL); | |
630 | RCU_INIT_POINTER(nf_nat_sdp_port_hook, NULL); | |
631 | RCU_INIT_POINTER(nf_nat_sdp_session_hook, NULL); | |
632 | RCU_INIT_POINTER(nf_nat_sdp_media_hook, NULL); | |
544d5c7d | 633 | nf_ct_helper_expectfn_unregister(&sip_nat); |
9fafcd7b PM |
634 | synchronize_rcu(); |
635 | } | |
636 | ||
637 | static int __init nf_nat_sip_init(void) | |
638 | { | |
d1332e0a | 639 | BUG_ON(nf_nat_sip_hook != NULL); |
48f8ac26 | 640 | BUG_ON(nf_nat_sip_seq_adjust_hook != NULL); |
0f32a40f | 641 | BUG_ON(nf_nat_sip_expect_hook != NULL); |
4ab9e64e | 642 | BUG_ON(nf_nat_sdp_addr_hook != NULL); |
c7f485ab | 643 | BUG_ON(nf_nat_sdp_port_hook != NULL); |
4ab9e64e PM |
644 | BUG_ON(nf_nat_sdp_session_hook != NULL); |
645 | BUG_ON(nf_nat_sdp_media_hook != NULL); | |
9a664821 PM |
646 | RCU_INIT_POINTER(nf_nat_sip_hook, nf_nat_sip); |
647 | RCU_INIT_POINTER(nf_nat_sip_seq_adjust_hook, nf_nat_sip_seq_adjust); | |
648 | RCU_INIT_POINTER(nf_nat_sip_expect_hook, nf_nat_sip_expect); | |
649 | RCU_INIT_POINTER(nf_nat_sdp_addr_hook, nf_nat_sdp_addr); | |
650 | RCU_INIT_POINTER(nf_nat_sdp_port_hook, nf_nat_sdp_port); | |
651 | RCU_INIT_POINTER(nf_nat_sdp_session_hook, nf_nat_sdp_session); | |
652 | RCU_INIT_POINTER(nf_nat_sdp_media_hook, nf_nat_sdp_media); | |
544d5c7d | 653 | nf_ct_helper_expectfn_register(&sip_nat); |
9fafcd7b PM |
654 | return 0; |
655 | } | |
656 | ||
657 | module_init(nf_nat_sip_init); | |
658 | module_exit(nf_nat_sip_fini); |