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, |
5aed9387 | 233 | poff, plen, buffer, buflen)) { |
b20ab9cc | 234 | nf_ct_helper_log(skb, ct, "cannot mangle received"); |
720ac708 | 235 | return NF_DROP; |
5aed9387 | 236 | } |
720ac708 PM |
237 | } |
238 | ||
239 | /* The rport= parameter (RFC 3581) contains the port number | |
240 | * from which the server received the request. */ | |
241 | if (ct_sip_parse_numerical_param(ct, *dptr, matchend, *datalen, | |
242 | "rport=", &poff, &plen, | |
243 | &n) > 0 && | |
244 | htons(n) == ct->tuplehash[dir].tuple.dst.u.udp.port && | |
245 | htons(n) != ct->tuplehash[!dir].tuple.src.u.udp.port) { | |
246 | __be16 p = ct->tuplehash[!dir].tuple.src.u.udp.port; | |
247 | buflen = sprintf(buffer, "%u", ntohs(p)); | |
051966c0 | 248 | if (!mangle_packet(skb, protoff, dataoff, dptr, datalen, |
b20ab9cc PNA |
249 | poff, plen, buffer, buflen)) { |
250 | nf_ct_helper_log(skb, ct, "cannot mangle rport"); | |
720ac708 | 251 | return NF_DROP; |
b20ab9cc | 252 | } |
720ac708 | 253 | } |
9fafcd7b PM |
254 | } |
255 | ||
720ac708 | 256 | next: |
c978cd3a | 257 | /* Translate Contact headers */ |
3b6b9fab | 258 | coff = 0; |
c978cd3a | 259 | in_header = 0; |
3b6b9fab | 260 | while (ct_sip_parse_header_uri(ct, *dptr, &coff, *datalen, |
c978cd3a PM |
261 | SIP_HDR_CONTACT, &in_header, |
262 | &matchoff, &matchlen, | |
263 | &addr, &port) > 0) { | |
051966c0 PM |
264 | if (!map_addr(skb, protoff, dataoff, dptr, datalen, |
265 | matchoff, matchlen, | |
b20ab9cc PNA |
266 | &addr, port)) { |
267 | nf_ct_helper_log(skb, ct, "cannot mangle contact"); | |
c978cd3a | 268 | return NF_DROP; |
b20ab9cc | 269 | } |
c978cd3a PM |
270 | } |
271 | ||
051966c0 | 272 | if (!map_sip_addr(skb, protoff, dataoff, dptr, datalen, SIP_HDR_FROM) || |
b20ab9cc PNA |
273 | !map_sip_addr(skb, protoff, dataoff, dptr, datalen, SIP_HDR_TO)) { |
274 | nf_ct_helper_log(skb, ct, "cannot mangle SIP from/to"); | |
9fafcd7b | 275 | return NF_DROP; |
b20ab9cc | 276 | } |
48f8ac26 | 277 | |
7266507d KC |
278 | /* Mangle destination port for Cisco phones, then fix up checksums */ |
279 | if (dir == IP_CT_DIR_REPLY && ct_sip_info->forced_dport) { | |
280 | struct udphdr *uh; | |
281 | ||
b20ab9cc PNA |
282 | if (!skb_make_writable(skb, skb->len)) { |
283 | nf_ct_helper_log(skb, ct, "cannot mangle packet"); | |
7266507d | 284 | return NF_DROP; |
b20ab9cc | 285 | } |
7266507d KC |
286 | |
287 | uh = (void *)skb->data + protoff; | |
288 | uh->dest = ct_sip_info->forced_dport; | |
289 | ||
290 | if (!nf_nat_mangle_udp_packet(skb, ct, ctinfo, protoff, | |
b20ab9cc PNA |
291 | 0, 0, NULL, 0)) { |
292 | nf_ct_helper_log(skb, ct, "cannot mangle packet"); | |
7266507d | 293 | return NF_DROP; |
b20ab9cc | 294 | } |
7266507d KC |
295 | } |
296 | ||
9fafcd7b PM |
297 | return NF_ACCEPT; |
298 | } | |
299 | ||
9a664821 PM |
300 | static void nf_nat_sip_seq_adjust(struct sk_buff *skb, unsigned int protoff, |
301 | s16 off) | |
48f8ac26 PM |
302 | { |
303 | enum ip_conntrack_info ctinfo; | |
304 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
305 | const struct tcphdr *th; | |
306 | ||
307 | if (nf_ct_protonum(ct) != IPPROTO_TCP || off == 0) | |
308 | return; | |
309 | ||
9a664821 | 310 | th = (struct tcphdr *)(skb->data + protoff); |
48f8ac26 PM |
311 | nf_nat_set_seq_adjust(ct, ctinfo, th->seq, off); |
312 | } | |
313 | ||
0f32a40f | 314 | /* Handles expected signalling connections and media streams */ |
9a664821 | 315 | static void nf_nat_sip_expected(struct nf_conn *ct, |
0f32a40f PM |
316 | struct nf_conntrack_expect *exp) |
317 | { | |
c7232c99 | 318 | struct nf_nat_range range; |
0f32a40f PM |
319 | |
320 | /* This must be a fresh one. */ | |
321 | BUG_ON(ct->status & IPS_NAT_DONE_MASK); | |
322 | ||
323 | /* For DST manip, map port here to where it's expected. */ | |
cbc9f2f4 | 324 | range.flags = (NF_NAT_RANGE_MAP_IPS | NF_NAT_RANGE_PROTO_SPECIFIED); |
c7232c99 PM |
325 | range.min_proto = range.max_proto = exp->saved_proto; |
326 | range.min_addr = range.max_addr = exp->saved_addr; | |
cbc9f2f4 | 327 | nf_nat_setup_info(ct, &range, NF_NAT_MANIP_DST); |
0f32a40f PM |
328 | |
329 | /* Change src to where master sends to, but only if the connection | |
330 | * actually came from the same source. */ | |
9a664821 PM |
331 | if (nf_inet_addr_cmp(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3, |
332 | &ct->master->tuplehash[exp->dir].tuple.src.u3)) { | |
cbc9f2f4 | 333 | range.flags = NF_NAT_RANGE_MAP_IPS; |
c7232c99 PM |
334 | range.min_addr = range.max_addr |
335 | = ct->master->tuplehash[!exp->dir].tuple.dst.u3; | |
cbc9f2f4 | 336 | nf_nat_setup_info(ct, &range, NF_NAT_MANIP_SRC); |
0f32a40f PM |
337 | } |
338 | } | |
339 | ||
9a664821 | 340 | static unsigned int nf_nat_sip_expect(struct sk_buff *skb, unsigned int protoff, |
051966c0 | 341 | unsigned int dataoff, |
0f32a40f PM |
342 | const char **dptr, unsigned int *datalen, |
343 | struct nf_conntrack_expect *exp, | |
344 | unsigned int matchoff, | |
345 | unsigned int matchlen) | |
346 | { | |
347 | enum ip_conntrack_info ctinfo; | |
348 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
349 | enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); | |
7266507d | 350 | struct nf_ct_sip_master *ct_sip_info = nfct_help_data(ct); |
9a664821 | 351 | union nf_inet_addr newaddr; |
0f32a40f | 352 | u_int16_t port; |
7266507d | 353 | __be16 srcport; |
9a664821 | 354 | char buffer[INET6_ADDRSTRLEN + sizeof("[]:nnnnn")]; |
95c96174 | 355 | unsigned int buflen; |
0f32a40f PM |
356 | |
357 | /* Connection will come from reply */ | |
9a664821 PM |
358 | if (nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.src.u3, |
359 | &ct->tuplehash[!dir].tuple.dst.u3)) | |
360 | newaddr = exp->tuple.dst.u3; | |
0f32a40f | 361 | else |
9a664821 | 362 | newaddr = ct->tuplehash[!dir].tuple.dst.u3; |
0f32a40f PM |
363 | |
364 | /* If the signalling port matches the connection's source port in the | |
365 | * original direction, try to use the destination port in the opposite | |
366 | * direction. */ | |
7266507d KC |
367 | srcport = ct_sip_info->forced_dport ? : |
368 | ct->tuplehash[dir].tuple.src.u.udp.port; | |
369 | if (exp->tuple.dst.u.udp.port == srcport) | |
0f32a40f PM |
370 | port = ntohs(ct->tuplehash[!dir].tuple.dst.u.udp.port); |
371 | else | |
372 | port = ntohs(exp->tuple.dst.u.udp.port); | |
373 | ||
c7232c99 | 374 | exp->saved_addr = exp->tuple.dst.u3; |
9a664821 | 375 | exp->tuple.dst.u3 = newaddr; |
0f32a40f PM |
376 | exp->saved_proto.udp.port = exp->tuple.dst.u.udp.port; |
377 | exp->dir = !dir; | |
9a664821 | 378 | exp->expectfn = nf_nat_sip_expected; |
0f32a40f PM |
379 | |
380 | for (; port != 0; port++) { | |
5b92b61f PNA |
381 | int ret; |
382 | ||
0f32a40f | 383 | exp->tuple.dst.u.udp.port = htons(port); |
5b92b61f PNA |
384 | ret = nf_ct_expect_related(exp); |
385 | if (ret == 0) | |
386 | break; | |
387 | else if (ret != -EBUSY) { | |
388 | port = 0; | |
0f32a40f | 389 | break; |
5b92b61f | 390 | } |
0f32a40f PM |
391 | } |
392 | ||
b20ab9cc PNA |
393 | if (port == 0) { |
394 | nf_ct_helper_log(skb, ct, "all ports in use for SIP"); | |
0f32a40f | 395 | return NF_DROP; |
b20ab9cc | 396 | } |
0f32a40f | 397 | |
9a664821 | 398 | if (!nf_inet_addr_cmp(&exp->tuple.dst.u3, &exp->saved_addr) || |
0f32a40f | 399 | exp->tuple.dst.u.udp.port != exp->saved_proto.udp.port) { |
9a664821 | 400 | buflen = sip_sprintf_addr_port(ct, buffer, &newaddr, port); |
051966c0 | 401 | if (!mangle_packet(skb, protoff, dataoff, dptr, datalen, |
b20ab9cc PNA |
402 | matchoff, matchlen, buffer, buflen)) { |
403 | nf_ct_helper_log(skb, ct, "cannot mangle packet"); | |
0f32a40f | 404 | goto err; |
b20ab9cc | 405 | } |
0f32a40f PM |
406 | } |
407 | return NF_ACCEPT; | |
408 | ||
409 | err: | |
410 | nf_ct_unexpect_related(exp); | |
411 | return NF_DROP; | |
412 | } | |
413 | ||
051966c0 PM |
414 | static int mangle_content_len(struct sk_buff *skb, unsigned int protoff, |
415 | unsigned int dataoff, | |
3e9b4600 | 416 | const char **dptr, unsigned int *datalen) |
9fafcd7b | 417 | { |
212440a7 PM |
418 | enum ip_conntrack_info ctinfo; |
419 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
3e9b4600 PM |
420 | unsigned int matchoff, matchlen; |
421 | char buffer[sizeof("65536")]; | |
422 | int buflen, c_len; | |
9fafcd7b | 423 | |
3e9b4600 PM |
424 | /* Get actual SDP length */ |
425 | if (ct_sip_get_sdp_header(ct, *dptr, 0, *datalen, | |
426 | SDP_HDR_VERSION, SDP_HDR_UNSPEC, | |
427 | &matchoff, &matchlen) <= 0) | |
428 | return 0; | |
429 | c_len = *datalen - matchoff + strlen("v="); | |
430 | ||
431 | /* Now, update SDP length */ | |
ea45f12a PM |
432 | if (ct_sip_get_header(ct, *dptr, 0, *datalen, SIP_HDR_CONTENT_LENGTH, |
433 | &matchoff, &matchlen) <= 0) | |
9fafcd7b PM |
434 | return 0; |
435 | ||
3e9b4600 | 436 | buflen = sprintf(buffer, "%u", c_len); |
051966c0 PM |
437 | return mangle_packet(skb, protoff, dataoff, dptr, datalen, |
438 | matchoff, matchlen, buffer, buflen); | |
9fafcd7b PM |
439 | } |
440 | ||
051966c0 PM |
441 | static int mangle_sdp_packet(struct sk_buff *skb, unsigned int protoff, |
442 | unsigned int dataoff, | |
3b6b9fab PM |
443 | const char **dptr, unsigned int *datalen, |
444 | unsigned int sdpoff, | |
c71529e4 HX |
445 | enum sdp_header_types type, |
446 | enum sdp_header_types term, | |
447 | char *buffer, int buflen) | |
9fafcd7b | 448 | { |
212440a7 PM |
449 | enum ip_conntrack_info ctinfo; |
450 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
3e9b4600 | 451 | unsigned int matchlen, matchoff; |
9fafcd7b | 452 | |
3b6b9fab | 453 | if (ct_sip_get_sdp_header(ct, *dptr, sdpoff, *datalen, type, term, |
3e9b4600 | 454 | &matchoff, &matchlen) <= 0) |
c71529e4 | 455 | return -ENOENT; |
051966c0 PM |
456 | return mangle_packet(skb, protoff, dataoff, dptr, datalen, |
457 | matchoff, matchlen, buffer, buflen) ? 0 : -EINVAL; | |
9fafcd7b PM |
458 | } |
459 | ||
9a664821 | 460 | static unsigned int nf_nat_sdp_addr(struct sk_buff *skb, unsigned int protoff, |
051966c0 | 461 | unsigned int dataoff, |
3b6b9fab PM |
462 | const char **dptr, unsigned int *datalen, |
463 | unsigned int sdpoff, | |
4ab9e64e PM |
464 | enum sdp_header_types type, |
465 | enum sdp_header_types term, | |
466 | const union nf_inet_addr *addr) | |
9fafcd7b | 467 | { |
9a664821 PM |
468 | enum ip_conntrack_info ctinfo; |
469 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
470 | char buffer[INET6_ADDRSTRLEN]; | |
4ab9e64e | 471 | unsigned int buflen; |
9fafcd7b | 472 | |
9a664821 | 473 | buflen = sip_sprintf_addr(ct, buffer, addr, false); |
051966c0 PM |
474 | if (mangle_sdp_packet(skb, protoff, dataoff, dptr, datalen, |
475 | sdpoff, type, term, buffer, buflen)) | |
9fafcd7b PM |
476 | return 0; |
477 | ||
051966c0 | 478 | return mangle_content_len(skb, protoff, dataoff, dptr, datalen); |
4ab9e64e PM |
479 | } |
480 | ||
9a664821 | 481 | static unsigned int nf_nat_sdp_port(struct sk_buff *skb, unsigned int protoff, |
051966c0 | 482 | unsigned int dataoff, |
3b6b9fab | 483 | const char **dptr, unsigned int *datalen, |
4ab9e64e PM |
484 | unsigned int matchoff, |
485 | unsigned int matchlen, | |
486 | u_int16_t port) | |
487 | { | |
488 | char buffer[sizeof("nnnnn")]; | |
489 | unsigned int buflen; | |
490 | ||
491 | buflen = sprintf(buffer, "%u", port); | |
051966c0 PM |
492 | if (!mangle_packet(skb, protoff, dataoff, dptr, datalen, |
493 | matchoff, matchlen, buffer, buflen)) | |
9fafcd7b PM |
494 | return 0; |
495 | ||
051966c0 | 496 | return mangle_content_len(skb, protoff, dataoff, dptr, datalen); |
4ab9e64e PM |
497 | } |
498 | ||
9a664821 | 499 | static unsigned int nf_nat_sdp_session(struct sk_buff *skb, unsigned int protoff, |
051966c0 | 500 | unsigned int dataoff, |
3b6b9fab PM |
501 | const char **dptr, unsigned int *datalen, |
502 | unsigned int sdpoff, | |
4ab9e64e PM |
503 | const union nf_inet_addr *addr) |
504 | { | |
9a664821 PM |
505 | enum ip_conntrack_info ctinfo; |
506 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
507 | char buffer[INET6_ADDRSTRLEN]; | |
4ab9e64e PM |
508 | unsigned int buflen; |
509 | ||
510 | /* Mangle session description owner and contact addresses */ | |
9a664821 | 511 | buflen = sip_sprintf_addr(ct, buffer, addr, false); |
051966c0 | 512 | if (mangle_sdp_packet(skb, protoff, dataoff, dptr, datalen, sdpoff, |
9a664821 | 513 | SDP_HDR_OWNER, SDP_HDR_MEDIA, buffer, buflen)) |
4ab9e64e PM |
514 | return 0; |
515 | ||
051966c0 | 516 | switch (mangle_sdp_packet(skb, protoff, dataoff, dptr, datalen, sdpoff, |
9a664821 | 517 | SDP_HDR_CONNECTION, SDP_HDR_MEDIA, |
c71529e4 HX |
518 | buffer, buflen)) { |
519 | case 0: | |
520 | /* | |
521 | * RFC 2327: | |
522 | * | |
523 | * Session description | |
524 | * | |
525 | * c=* (connection information - not required if included in all media) | |
526 | */ | |
527 | case -ENOENT: | |
528 | break; | |
529 | default: | |
9fafcd7b | 530 | return 0; |
c71529e4 | 531 | } |
9fafcd7b | 532 | |
051966c0 | 533 | return mangle_content_len(skb, protoff, dataoff, dptr, datalen); |
9fafcd7b PM |
534 | } |
535 | ||
536 | /* So, this packet has hit the connection tracking matching code. | |
537 | Mangle it, and change the expectation to match the new version. */ | |
9a664821 | 538 | static unsigned int nf_nat_sdp_media(struct sk_buff *skb, unsigned int protoff, |
051966c0 | 539 | unsigned int dataoff, |
3b6b9fab | 540 | const char **dptr, unsigned int *datalen, |
4ab9e64e PM |
541 | struct nf_conntrack_expect *rtp_exp, |
542 | struct nf_conntrack_expect *rtcp_exp, | |
543 | unsigned int mediaoff, | |
544 | unsigned int medialen, | |
545 | union nf_inet_addr *rtp_addr) | |
9fafcd7b | 546 | { |
212440a7 PM |
547 | enum ip_conntrack_info ctinfo; |
548 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
9fafcd7b | 549 | enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); |
9fafcd7b PM |
550 | u_int16_t port; |
551 | ||
9fafcd7b | 552 | /* Connection will come from reply */ |
9a664821 PM |
553 | if (nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.src.u3, |
554 | &ct->tuplehash[!dir].tuple.dst.u3)) | |
555 | *rtp_addr = rtp_exp->tuple.dst.u3; | |
f4a607bf | 556 | else |
9a664821 | 557 | *rtp_addr = ct->tuplehash[!dir].tuple.dst.u3; |
9fafcd7b | 558 | |
c7232c99 | 559 | rtp_exp->saved_addr = rtp_exp->tuple.dst.u3; |
9a664821 | 560 | rtp_exp->tuple.dst.u3 = *rtp_addr; |
a9c1d359 PM |
561 | rtp_exp->saved_proto.udp.port = rtp_exp->tuple.dst.u.udp.port; |
562 | rtp_exp->dir = !dir; | |
9a664821 | 563 | rtp_exp->expectfn = nf_nat_sip_expected; |
a9c1d359 | 564 | |
c7232c99 | 565 | rtcp_exp->saved_addr = rtcp_exp->tuple.dst.u3; |
9a664821 | 566 | rtcp_exp->tuple.dst.u3 = *rtp_addr; |
a9c1d359 PM |
567 | rtcp_exp->saved_proto.udp.port = rtcp_exp->tuple.dst.u.udp.port; |
568 | rtcp_exp->dir = !dir; | |
9a664821 | 569 | rtcp_exp->expectfn = nf_nat_sip_expected; |
a9c1d359 PM |
570 | |
571 | /* Try to get same pair of ports: if not, try to change them. */ | |
572 | for (port = ntohs(rtp_exp->tuple.dst.u.udp.port); | |
573 | port != 0; port += 2) { | |
5b92b61f PNA |
574 | int ret; |
575 | ||
a9c1d359 | 576 | rtp_exp->tuple.dst.u.udp.port = htons(port); |
5b92b61f PNA |
577 | ret = nf_ct_expect_related(rtp_exp); |
578 | if (ret == -EBUSY) | |
a9c1d359 | 579 | continue; |
5b92b61f PNA |
580 | else if (ret < 0) { |
581 | port = 0; | |
582 | break; | |
583 | } | |
a9c1d359 | 584 | rtcp_exp->tuple.dst.u.udp.port = htons(port + 1); |
5b92b61f PNA |
585 | ret = nf_ct_expect_related(rtcp_exp); |
586 | if (ret == 0) | |
9fafcd7b | 587 | break; |
3f509c68 PNA |
588 | else if (ret == -EBUSY) { |
589 | nf_ct_unexpect_related(rtp_exp); | |
590 | continue; | |
591 | } else if (ret < 0) { | |
5b92b61f PNA |
592 | nf_ct_unexpect_related(rtp_exp); |
593 | port = 0; | |
594 | break; | |
595 | } | |
9fafcd7b PM |
596 | } |
597 | ||
b20ab9cc PNA |
598 | if (port == 0) { |
599 | nf_ct_helper_log(skb, ct, "all ports in use for SDP media"); | |
4ab9e64e | 600 | goto err1; |
b20ab9cc | 601 | } |
4ab9e64e PM |
602 | |
603 | /* Update media port. */ | |
604 | if (rtp_exp->tuple.dst.u.udp.port != rtp_exp->saved_proto.udp.port && | |
9a664821 | 605 | !nf_nat_sdp_port(skb, protoff, dataoff, dptr, datalen, |
b20ab9cc PNA |
606 | mediaoff, medialen, port)) { |
607 | nf_ct_helper_log(skb, ct, "cannot mangle SDP message"); | |
4ab9e64e | 608 | goto err2; |
b20ab9cc | 609 | } |
9fafcd7b | 610 | |
9fafcd7b | 611 | return NF_ACCEPT; |
4ab9e64e PM |
612 | |
613 | err2: | |
614 | nf_ct_unexpect_related(rtp_exp); | |
615 | nf_ct_unexpect_related(rtcp_exp); | |
616 | err1: | |
617 | return NF_DROP; | |
9fafcd7b PM |
618 | } |
619 | ||
544d5c7d | 620 | static struct nf_ct_helper_expectfn sip_nat = { |
9a664821 PM |
621 | .name = "sip", |
622 | .expectfn = nf_nat_sip_expected, | |
544d5c7d PNA |
623 | }; |
624 | ||
9fafcd7b PM |
625 | static void __exit nf_nat_sip_fini(void) |
626 | { | |
a9b3cd7f SH |
627 | RCU_INIT_POINTER(nf_nat_sip_hook, NULL); |
628 | RCU_INIT_POINTER(nf_nat_sip_seq_adjust_hook, NULL); | |
629 | RCU_INIT_POINTER(nf_nat_sip_expect_hook, NULL); | |
630 | RCU_INIT_POINTER(nf_nat_sdp_addr_hook, NULL); | |
631 | RCU_INIT_POINTER(nf_nat_sdp_port_hook, NULL); | |
632 | RCU_INIT_POINTER(nf_nat_sdp_session_hook, NULL); | |
633 | RCU_INIT_POINTER(nf_nat_sdp_media_hook, NULL); | |
544d5c7d | 634 | nf_ct_helper_expectfn_unregister(&sip_nat); |
9fafcd7b PM |
635 | synchronize_rcu(); |
636 | } | |
637 | ||
638 | static int __init nf_nat_sip_init(void) | |
639 | { | |
d1332e0a | 640 | BUG_ON(nf_nat_sip_hook != NULL); |
48f8ac26 | 641 | BUG_ON(nf_nat_sip_seq_adjust_hook != NULL); |
0f32a40f | 642 | BUG_ON(nf_nat_sip_expect_hook != NULL); |
4ab9e64e | 643 | BUG_ON(nf_nat_sdp_addr_hook != NULL); |
c7f485ab | 644 | BUG_ON(nf_nat_sdp_port_hook != NULL); |
4ab9e64e PM |
645 | BUG_ON(nf_nat_sdp_session_hook != NULL); |
646 | BUG_ON(nf_nat_sdp_media_hook != NULL); | |
9a664821 PM |
647 | RCU_INIT_POINTER(nf_nat_sip_hook, nf_nat_sip); |
648 | RCU_INIT_POINTER(nf_nat_sip_seq_adjust_hook, nf_nat_sip_seq_adjust); | |
649 | RCU_INIT_POINTER(nf_nat_sip_expect_hook, nf_nat_sip_expect); | |
650 | RCU_INIT_POINTER(nf_nat_sdp_addr_hook, nf_nat_sdp_addr); | |
651 | RCU_INIT_POINTER(nf_nat_sdp_port_hook, nf_nat_sdp_port); | |
652 | RCU_INIT_POINTER(nf_nat_sdp_session_hook, nf_nat_sdp_session); | |
653 | RCU_INIT_POINTER(nf_nat_sdp_media_hook, nf_nat_sdp_media); | |
544d5c7d | 654 | nf_ct_helper_expectfn_register(&sip_nat); |
9fafcd7b PM |
655 | return 0; |
656 | } | |
657 | ||
658 | module_init(nf_nat_sip_init); | |
659 | module_exit(nf_nat_sip_fini); |