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f587de0e PM |
1 | /* |
2 | * H.323 extension for NAT alteration. | |
3 | * | |
4 | * Copyright (c) 2006 Jing Min Zhao <zhaojingmin@users.sourceforge.net> | |
5 | * | |
6 | * This source code is licensed under General Public License version 2. | |
7 | * | |
8 | * Based on the 'brute force' H.323 NAT module by | |
9 | * Jozsef Kadlecsik <kadlec@blackhole.kfki.hu> | |
10 | */ | |
11 | ||
12 | #include <linux/module.h> | |
13 | #include <linux/moduleparam.h> | |
14 | #include <linux/tcp.h> | |
15 | #include <net/tcp.h> | |
16 | ||
17 | #include <net/netfilter/nf_nat.h> | |
18 | #include <net/netfilter/nf_nat_helper.h> | |
19 | #include <net/netfilter/nf_nat_rule.h> | |
20 | #include <net/netfilter/nf_conntrack_helper.h> | |
21 | #include <net/netfilter/nf_conntrack_expect.h> | |
22 | #include <linux/netfilter/nf_conntrack_h323.h> | |
23 | ||
24 | #if 0 | |
25 | #define DEBUGP printk | |
26 | #else | |
27 | #define DEBUGP(format, args...) | |
28 | #endif | |
29 | ||
30 | /****************************************************************************/ | |
31 | static int set_addr(struct sk_buff **pskb, | |
32 | unsigned char **data, int dataoff, | |
33 | unsigned int addroff, __be32 ip, __be16 port) | |
34 | { | |
35 | enum ip_conntrack_info ctinfo; | |
36 | struct nf_conn *ct = ip_conntrack_get(*pskb, &ctinfo); | |
37 | struct { | |
38 | __be32 ip; | |
39 | __be16 port; | |
40 | } __attribute__ ((__packed__)) buf; | |
41 | struct tcphdr _tcph, *th; | |
42 | ||
43 | buf.ip = ip; | |
44 | buf.port = port; | |
45 | addroff += dataoff; | |
46 | ||
eddc9ec5 | 47 | if (ip_hdr(*pskb)->protocol == IPPROTO_TCP) { |
f587de0e PM |
48 | if (!nf_nat_mangle_tcp_packet(pskb, ct, ctinfo, |
49 | addroff, sizeof(buf), | |
50 | (char *) &buf, sizeof(buf))) { | |
51 | if (net_ratelimit()) | |
52 | printk("nf_nat_h323: nf_nat_mangle_tcp_packet" | |
53 | " error\n"); | |
54 | return -1; | |
55 | } | |
56 | ||
57 | /* Relocate data pointer */ | |
c9bdd4b5 | 58 | th = skb_header_pointer(*pskb, ip_hdrlen(*pskb), |
f587de0e PM |
59 | sizeof(_tcph), &_tcph); |
60 | if (th == NULL) | |
61 | return -1; | |
c9bdd4b5 | 62 | *data = (*pskb)->data + ip_hdrlen(*pskb) + |
f587de0e PM |
63 | th->doff * 4 + dataoff; |
64 | } else { | |
65 | if (!nf_nat_mangle_udp_packet(pskb, ct, ctinfo, | |
66 | addroff, sizeof(buf), | |
67 | (char *) &buf, sizeof(buf))) { | |
68 | if (net_ratelimit()) | |
69 | printk("nf_nat_h323: nf_nat_mangle_udp_packet" | |
70 | " error\n"); | |
71 | return -1; | |
72 | } | |
73 | /* nf_nat_mangle_udp_packet uses skb_make_writable() to copy | |
74 | * or pull everything in a linear buffer, so we can safely | |
75 | * use the skb pointers now */ | |
c9bdd4b5 ACM |
76 | *data = ((*pskb)->data + ip_hdrlen(*pskb) + |
77 | sizeof(struct udphdr)); | |
f587de0e PM |
78 | } |
79 | ||
80 | return 0; | |
81 | } | |
82 | ||
83 | /****************************************************************************/ | |
84 | static int set_h225_addr(struct sk_buff **pskb, | |
85 | unsigned char **data, int dataoff, | |
86 | TransportAddress *taddr, | |
87 | union nf_conntrack_address *addr, __be16 port) | |
88 | { | |
89 | return set_addr(pskb, data, dataoff, taddr->ipAddress.ip, | |
90 | addr->ip, port); | |
91 | } | |
92 | ||
93 | /****************************************************************************/ | |
94 | static int set_h245_addr(struct sk_buff **pskb, | |
95 | unsigned char **data, int dataoff, | |
96 | H245_TransportAddress *taddr, | |
97 | union nf_conntrack_address *addr, __be16 port) | |
98 | { | |
99 | return set_addr(pskb, data, dataoff, | |
100 | taddr->unicastAddress.iPAddress.network, | |
101 | addr->ip, port); | |
102 | } | |
103 | ||
104 | /****************************************************************************/ | |
105 | static int set_sig_addr(struct sk_buff **pskb, struct nf_conn *ct, | |
106 | enum ip_conntrack_info ctinfo, | |
107 | unsigned char **data, | |
108 | TransportAddress *taddr, int count) | |
109 | { | |
110 | struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info; | |
111 | int dir = CTINFO2DIR(ctinfo); | |
112 | int i; | |
113 | __be16 port; | |
114 | union nf_conntrack_address addr; | |
115 | ||
116 | for (i = 0; i < count; i++) { | |
117 | if (get_h225_addr(ct, *data, &taddr[i], &addr, &port)) { | |
118 | if (addr.ip == ct->tuplehash[dir].tuple.src.u3.ip && | |
119 | port == info->sig_port[dir]) { | |
120 | /* GW->GK */ | |
121 | ||
122 | /* Fix for Gnomemeeting */ | |
123 | if (i > 0 && | |
124 | get_h225_addr(ct, *data, &taddr[0], | |
125 | &addr, &port) && | |
126 | (ntohl(addr.ip) & 0xff000000) == 0x7f000000) | |
127 | i = 0; | |
128 | ||
129 | DEBUGP | |
130 | ("nf_nat_ras: set signal address " | |
131 | "%u.%u.%u.%u:%hu->%u.%u.%u.%u:%hu\n", | |
132 | NIPQUAD(ip), port, | |
133 | NIPQUAD(ct->tuplehash[!dir].tuple.dst. | |
134 | ip), info->sig_port[!dir]); | |
135 | return set_h225_addr(pskb, data, 0, &taddr[i], | |
136 | &ct->tuplehash[!dir]. | |
137 | tuple.dst.u3, | |
138 | info->sig_port[!dir]); | |
139 | } else if (addr.ip == ct->tuplehash[dir].tuple.dst.u3.ip && | |
140 | port == info->sig_port[dir]) { | |
141 | /* GK->GW */ | |
142 | DEBUGP | |
143 | ("nf_nat_ras: set signal address " | |
144 | "%u.%u.%u.%u:%hu->%u.%u.%u.%u:%hu\n", | |
145 | NIPQUAD(ip), port, | |
146 | NIPQUAD(ct->tuplehash[!dir].tuple.src. | |
147 | ip), info->sig_port[!dir]); | |
148 | return set_h225_addr(pskb, data, 0, &taddr[i], | |
149 | &ct->tuplehash[!dir]. | |
150 | tuple.src.u3, | |
151 | info->sig_port[!dir]); | |
152 | } | |
153 | } | |
154 | } | |
155 | ||
156 | return 0; | |
157 | } | |
158 | ||
159 | /****************************************************************************/ | |
160 | static int set_ras_addr(struct sk_buff **pskb, struct nf_conn *ct, | |
161 | enum ip_conntrack_info ctinfo, | |
162 | unsigned char **data, | |
163 | TransportAddress *taddr, int count) | |
164 | { | |
165 | int dir = CTINFO2DIR(ctinfo); | |
166 | int i; | |
167 | __be16 port; | |
168 | union nf_conntrack_address addr; | |
169 | ||
170 | for (i = 0; i < count; i++) { | |
171 | if (get_h225_addr(ct, *data, &taddr[i], &addr, &port) && | |
172 | addr.ip == ct->tuplehash[dir].tuple.src.u3.ip && | |
173 | port == ct->tuplehash[dir].tuple.src.u.udp.port) { | |
174 | DEBUGP("nf_nat_ras: set rasAddress " | |
175 | "%u.%u.%u.%u:%hu->%u.%u.%u.%u:%hu\n", | |
176 | NIPQUAD(ip), ntohs(port), | |
177 | NIPQUAD(ct->tuplehash[!dir].tuple.dst.u3.ip), | |
178 | ntohs(ct->tuplehash[!dir].tuple.dst.u.udp. | |
179 | port)); | |
180 | return set_h225_addr(pskb, data, 0, &taddr[i], | |
181 | &ct->tuplehash[!dir].tuple.dst.u3, | |
182 | ct->tuplehash[!dir].tuple. | |
183 | dst.u.udp.port); | |
184 | } | |
185 | } | |
186 | ||
187 | return 0; | |
188 | } | |
189 | ||
190 | /****************************************************************************/ | |
191 | static int nat_rtp_rtcp(struct sk_buff **pskb, struct nf_conn *ct, | |
192 | enum ip_conntrack_info ctinfo, | |
193 | unsigned char **data, int dataoff, | |
194 | H245_TransportAddress *taddr, | |
195 | __be16 port, __be16 rtp_port, | |
196 | struct nf_conntrack_expect *rtp_exp, | |
197 | struct nf_conntrack_expect *rtcp_exp) | |
198 | { | |
199 | struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info; | |
200 | int dir = CTINFO2DIR(ctinfo); | |
201 | int i; | |
202 | u_int16_t nated_port; | |
203 | ||
204 | /* Set expectations for NAT */ | |
205 | rtp_exp->saved_proto.udp.port = rtp_exp->tuple.dst.u.udp.port; | |
206 | rtp_exp->expectfn = nf_nat_follow_master; | |
207 | rtp_exp->dir = !dir; | |
208 | rtcp_exp->saved_proto.udp.port = rtcp_exp->tuple.dst.u.udp.port; | |
209 | rtcp_exp->expectfn = nf_nat_follow_master; | |
210 | rtcp_exp->dir = !dir; | |
211 | ||
212 | /* Lookup existing expects */ | |
213 | for (i = 0; i < H323_RTP_CHANNEL_MAX; i++) { | |
214 | if (info->rtp_port[i][dir] == rtp_port) { | |
215 | /* Expected */ | |
216 | ||
217 | /* Use allocated ports first. This will refresh | |
218 | * the expects */ | |
219 | rtp_exp->tuple.dst.u.udp.port = info->rtp_port[i][dir]; | |
220 | rtcp_exp->tuple.dst.u.udp.port = | |
221 | htons(ntohs(info->rtp_port[i][dir]) + 1); | |
222 | break; | |
223 | } else if (info->rtp_port[i][dir] == 0) { | |
224 | /* Not expected */ | |
225 | break; | |
226 | } | |
227 | } | |
228 | ||
229 | /* Run out of expectations */ | |
230 | if (i >= H323_RTP_CHANNEL_MAX) { | |
231 | if (net_ratelimit()) | |
232 | printk("nf_nat_h323: out of expectations\n"); | |
233 | return 0; | |
234 | } | |
235 | ||
236 | /* Try to get a pair of ports. */ | |
237 | for (nated_port = ntohs(rtp_exp->tuple.dst.u.udp.port); | |
238 | nated_port != 0; nated_port += 2) { | |
239 | rtp_exp->tuple.dst.u.udp.port = htons(nated_port); | |
240 | if (nf_conntrack_expect_related(rtp_exp) == 0) { | |
241 | rtcp_exp->tuple.dst.u.udp.port = | |
242 | htons(nated_port + 1); | |
243 | if (nf_conntrack_expect_related(rtcp_exp) == 0) | |
244 | break; | |
245 | nf_conntrack_unexpect_related(rtp_exp); | |
246 | } | |
247 | } | |
248 | ||
249 | if (nated_port == 0) { /* No port available */ | |
250 | if (net_ratelimit()) | |
251 | printk("nf_nat_h323: out of RTP ports\n"); | |
252 | return 0; | |
253 | } | |
254 | ||
255 | /* Modify signal */ | |
256 | if (set_h245_addr(pskb, data, dataoff, taddr, | |
257 | &ct->tuplehash[!dir].tuple.dst.u3, | |
258 | htons((port & htons(1)) ? nated_port + 1 : | |
e905a9ed | 259 | nated_port)) == 0) { |
f587de0e PM |
260 | /* Save ports */ |
261 | info->rtp_port[i][dir] = rtp_port; | |
262 | info->rtp_port[i][!dir] = htons(nated_port); | |
263 | } else { | |
264 | nf_conntrack_unexpect_related(rtp_exp); | |
265 | nf_conntrack_unexpect_related(rtcp_exp); | |
266 | return -1; | |
267 | } | |
268 | ||
269 | /* Success */ | |
270 | DEBUGP("nf_nat_h323: expect RTP %u.%u.%u.%u:%hu->%u.%u.%u.%u:%hu\n", | |
271 | NIPQUAD(rtp_exp->tuple.src.ip), | |
272 | ntohs(rtp_exp->tuple.src.u.udp.port), | |
273 | NIPQUAD(rtp_exp->tuple.dst.ip), | |
274 | ntohs(rtp_exp->tuple.dst.u.udp.port)); | |
275 | DEBUGP("nf_nat_h323: expect RTCP %u.%u.%u.%u:%hu->%u.%u.%u.%u:%hu\n", | |
276 | NIPQUAD(rtcp_exp->tuple.src.ip), | |
277 | ntohs(rtcp_exp->tuple.src.u.udp.port), | |
278 | NIPQUAD(rtcp_exp->tuple.dst.ip), | |
279 | ntohs(rtcp_exp->tuple.dst.u.udp.port)); | |
280 | ||
281 | return 0; | |
282 | } | |
283 | ||
284 | /****************************************************************************/ | |
285 | static int nat_t120(struct sk_buff **pskb, struct nf_conn *ct, | |
286 | enum ip_conntrack_info ctinfo, | |
287 | unsigned char **data, int dataoff, | |
288 | H245_TransportAddress *taddr, __be16 port, | |
289 | struct nf_conntrack_expect *exp) | |
290 | { | |
291 | int dir = CTINFO2DIR(ctinfo); | |
292 | u_int16_t nated_port = ntohs(port); | |
293 | ||
294 | /* Set expectations for NAT */ | |
295 | exp->saved_proto.tcp.port = exp->tuple.dst.u.tcp.port; | |
296 | exp->expectfn = nf_nat_follow_master; | |
297 | exp->dir = !dir; | |
298 | ||
299 | /* Try to get same port: if not, try to change it. */ | |
300 | for (; nated_port != 0; nated_port++) { | |
301 | exp->tuple.dst.u.tcp.port = htons(nated_port); | |
302 | if (nf_conntrack_expect_related(exp) == 0) | |
303 | break; | |
304 | } | |
305 | ||
306 | if (nated_port == 0) { /* No port available */ | |
307 | if (net_ratelimit()) | |
308 | printk("nf_nat_h323: out of TCP ports\n"); | |
309 | return 0; | |
310 | } | |
311 | ||
312 | /* Modify signal */ | |
313 | if (set_h245_addr(pskb, data, dataoff, taddr, | |
314 | &ct->tuplehash[!dir].tuple.dst.u3, | |
315 | htons(nated_port)) < 0) { | |
316 | nf_conntrack_unexpect_related(exp); | |
317 | return -1; | |
318 | } | |
319 | ||
320 | DEBUGP("nf_nat_h323: expect T.120 %u.%u.%u.%u:%hu->%u.%u.%u.%u:%hu\n", | |
321 | NIPQUAD(exp->tuple.src.ip), ntohs(exp->tuple.src.u.tcp.port), | |
322 | NIPQUAD(exp->tuple.dst.ip), ntohs(exp->tuple.dst.u.tcp.port)); | |
323 | ||
324 | return 0; | |
325 | } | |
326 | ||
327 | /****************************************************************************/ | |
328 | static int nat_h245(struct sk_buff **pskb, struct nf_conn *ct, | |
329 | enum ip_conntrack_info ctinfo, | |
330 | unsigned char **data, int dataoff, | |
331 | TransportAddress *taddr, __be16 port, | |
332 | struct nf_conntrack_expect *exp) | |
333 | { | |
334 | struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info; | |
335 | int dir = CTINFO2DIR(ctinfo); | |
336 | u_int16_t nated_port = ntohs(port); | |
337 | ||
338 | /* Set expectations for NAT */ | |
339 | exp->saved_proto.tcp.port = exp->tuple.dst.u.tcp.port; | |
340 | exp->expectfn = nf_nat_follow_master; | |
341 | exp->dir = !dir; | |
342 | ||
343 | /* Check existing expects */ | |
344 | if (info->sig_port[dir] == port) | |
345 | nated_port = ntohs(info->sig_port[!dir]); | |
346 | ||
347 | /* Try to get same port: if not, try to change it. */ | |
348 | for (; nated_port != 0; nated_port++) { | |
349 | exp->tuple.dst.u.tcp.port = htons(nated_port); | |
350 | if (nf_conntrack_expect_related(exp) == 0) | |
351 | break; | |
352 | } | |
353 | ||
354 | if (nated_port == 0) { /* No port available */ | |
355 | if (net_ratelimit()) | |
356 | printk("nf_nat_q931: out of TCP ports\n"); | |
357 | return 0; | |
358 | } | |
359 | ||
360 | /* Modify signal */ | |
361 | if (set_h225_addr(pskb, data, dataoff, taddr, | |
362 | &ct->tuplehash[!dir].tuple.dst.u3, | |
363 | htons(nated_port)) == 0) { | |
364 | /* Save ports */ | |
365 | info->sig_port[dir] = port; | |
366 | info->sig_port[!dir] = htons(nated_port); | |
367 | } else { | |
368 | nf_conntrack_unexpect_related(exp); | |
369 | return -1; | |
370 | } | |
371 | ||
372 | DEBUGP("nf_nat_q931: expect H.245 %u.%u.%u.%u:%hu->%u.%u.%u.%u:%hu\n", | |
373 | NIPQUAD(exp->tuple.src.ip), ntohs(exp->tuple.src.u.tcp.port), | |
374 | NIPQUAD(exp->tuple.dst.ip), ntohs(exp->tuple.dst.u.tcp.port)); | |
375 | ||
376 | return 0; | |
377 | } | |
378 | ||
379 | /**************************************************************************** | |
380 | * This conntrack expect function replaces nf_conntrack_q931_expect() | |
381 | * which was set by nf_conntrack_h323.c. | |
382 | ****************************************************************************/ | |
383 | static void ip_nat_q931_expect(struct nf_conn *new, | |
384 | struct nf_conntrack_expect *this) | |
385 | { | |
386 | struct ip_nat_range range; | |
387 | ||
388 | if (this->tuple.src.u3.ip != 0) { /* Only accept calls from GK */ | |
389 | nf_nat_follow_master(new, this); | |
390 | return; | |
391 | } | |
392 | ||
393 | /* This must be a fresh one. */ | |
394 | BUG_ON(new->status & IPS_NAT_DONE_MASK); | |
395 | ||
396 | /* Change src to where master sends to */ | |
397 | range.flags = IP_NAT_RANGE_MAP_IPS; | |
398 | range.min_ip = range.max_ip = new->tuplehash[!this->dir].tuple.src.u3.ip; | |
399 | ||
400 | /* hook doesn't matter, but it has to do source manip */ | |
401 | nf_nat_setup_info(new, &range, NF_IP_POST_ROUTING); | |
402 | ||
403 | /* For DST manip, map port here to where it's expected. */ | |
404 | range.flags = (IP_NAT_RANGE_MAP_IPS | IP_NAT_RANGE_PROTO_SPECIFIED); | |
405 | range.min = range.max = this->saved_proto; | |
406 | range.min_ip = range.max_ip = | |
407 | new->master->tuplehash[!this->dir].tuple.src.u3.ip; | |
408 | ||
409 | /* hook doesn't matter, but it has to do destination manip */ | |
410 | nf_nat_setup_info(new, &range, NF_IP_PRE_ROUTING); | |
411 | } | |
412 | ||
413 | /****************************************************************************/ | |
414 | static int nat_q931(struct sk_buff **pskb, struct nf_conn *ct, | |
415 | enum ip_conntrack_info ctinfo, | |
416 | unsigned char **data, TransportAddress *taddr, int idx, | |
417 | __be16 port, struct nf_conntrack_expect *exp) | |
418 | { | |
419 | struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info; | |
420 | int dir = CTINFO2DIR(ctinfo); | |
421 | u_int16_t nated_port = ntohs(port); | |
422 | union nf_conntrack_address addr; | |
423 | ||
424 | /* Set expectations for NAT */ | |
425 | exp->saved_proto.tcp.port = exp->tuple.dst.u.tcp.port; | |
426 | exp->expectfn = ip_nat_q931_expect; | |
427 | exp->dir = !dir; | |
428 | ||
429 | /* Check existing expects */ | |
430 | if (info->sig_port[dir] == port) | |
431 | nated_port = ntohs(info->sig_port[!dir]); | |
432 | ||
433 | /* Try to get same port: if not, try to change it. */ | |
434 | for (; nated_port != 0; nated_port++) { | |
435 | exp->tuple.dst.u.tcp.port = htons(nated_port); | |
436 | if (nf_conntrack_expect_related(exp) == 0) | |
437 | break; | |
438 | } | |
439 | ||
440 | if (nated_port == 0) { /* No port available */ | |
441 | if (net_ratelimit()) | |
442 | printk("nf_nat_ras: out of TCP ports\n"); | |
443 | return 0; | |
444 | } | |
445 | ||
446 | /* Modify signal */ | |
447 | if (set_h225_addr(pskb, data, 0, &taddr[idx], | |
448 | &ct->tuplehash[!dir].tuple.dst.u3, | |
449 | htons(nated_port)) == 0) { | |
450 | /* Save ports */ | |
451 | info->sig_port[dir] = port; | |
452 | info->sig_port[!dir] = htons(nated_port); | |
453 | ||
454 | /* Fix for Gnomemeeting */ | |
455 | if (idx > 0 && | |
456 | get_h225_addr(ct, *data, &taddr[0], &addr, &port) && | |
457 | (ntohl(addr.ip) & 0xff000000) == 0x7f000000) { | |
458 | set_h225_addr_hook(pskb, data, 0, &taddr[0], | |
459 | &ct->tuplehash[!dir].tuple.dst.u3, | |
460 | info->sig_port[!dir]); | |
461 | } | |
462 | } else { | |
463 | nf_conntrack_unexpect_related(exp); | |
464 | return -1; | |
465 | } | |
466 | ||
467 | /* Success */ | |
468 | DEBUGP("nf_nat_ras: expect Q.931 %u.%u.%u.%u:%hu->%u.%u.%u.%u:%hu\n", | |
469 | NIPQUAD(exp->tuple.src.ip), ntohs(exp->tuple.src.u.tcp.port), | |
470 | NIPQUAD(exp->tuple.dst.ip), ntohs(exp->tuple.dst.u.tcp.port)); | |
471 | ||
472 | return 0; | |
473 | } | |
474 | ||
475 | /****************************************************************************/ | |
476 | static void ip_nat_callforwarding_expect(struct nf_conn *new, | |
477 | struct nf_conntrack_expect *this) | |
478 | { | |
479 | struct nf_nat_range range; | |
480 | ||
481 | /* This must be a fresh one. */ | |
482 | BUG_ON(new->status & IPS_NAT_DONE_MASK); | |
483 | ||
484 | /* Change src to where master sends to */ | |
485 | range.flags = IP_NAT_RANGE_MAP_IPS; | |
486 | range.min_ip = range.max_ip = new->tuplehash[!this->dir].tuple.src.u3.ip; | |
487 | ||
488 | /* hook doesn't matter, but it has to do source manip */ | |
489 | nf_nat_setup_info(new, &range, NF_IP_POST_ROUTING); | |
490 | ||
491 | /* For DST manip, map port here to where it's expected. */ | |
492 | range.flags = (IP_NAT_RANGE_MAP_IPS | IP_NAT_RANGE_PROTO_SPECIFIED); | |
493 | range.min = range.max = this->saved_proto; | |
494 | range.min_ip = range.max_ip = this->saved_ip; | |
495 | ||
496 | /* hook doesn't matter, but it has to do destination manip */ | |
497 | nf_nat_setup_info(new, &range, NF_IP_PRE_ROUTING); | |
498 | } | |
499 | ||
500 | /****************************************************************************/ | |
501 | static int nat_callforwarding(struct sk_buff **pskb, struct nf_conn *ct, | |
502 | enum ip_conntrack_info ctinfo, | |
503 | unsigned char **data, int dataoff, | |
504 | TransportAddress *taddr, __be16 port, | |
505 | struct nf_conntrack_expect *exp) | |
506 | { | |
507 | int dir = CTINFO2DIR(ctinfo); | |
508 | u_int16_t nated_port; | |
509 | ||
510 | /* Set expectations for NAT */ | |
511 | exp->saved_ip = exp->tuple.dst.u3.ip; | |
512 | exp->tuple.dst.u3.ip = ct->tuplehash[!dir].tuple.dst.u3.ip; | |
513 | exp->saved_proto.tcp.port = exp->tuple.dst.u.tcp.port; | |
514 | exp->expectfn = ip_nat_callforwarding_expect; | |
515 | exp->dir = !dir; | |
516 | ||
517 | /* Try to get same port: if not, try to change it. */ | |
518 | for (nated_port = ntohs(port); nated_port != 0; nated_port++) { | |
519 | exp->tuple.dst.u.tcp.port = htons(nated_port); | |
520 | if (nf_conntrack_expect_related(exp) == 0) | |
521 | break; | |
522 | } | |
523 | ||
524 | if (nated_port == 0) { /* No port available */ | |
525 | if (net_ratelimit()) | |
526 | printk("nf_nat_q931: out of TCP ports\n"); | |
527 | return 0; | |
528 | } | |
529 | ||
530 | /* Modify signal */ | |
531 | if (!set_h225_addr(pskb, data, dataoff, taddr, | |
532 | &ct->tuplehash[!dir].tuple.dst.u3, | |
533 | htons(nated_port)) == 0) { | |
534 | nf_conntrack_unexpect_related(exp); | |
535 | return -1; | |
536 | } | |
537 | ||
538 | /* Success */ | |
539 | DEBUGP("nf_nat_q931: expect Call Forwarding " | |
540 | "%u.%u.%u.%u:%hu->%u.%u.%u.%u:%hu\n", | |
541 | NIPQUAD(exp->tuple.src.ip), ntohs(exp->tuple.src.u.tcp.port), | |
542 | NIPQUAD(exp->tuple.dst.ip), ntohs(exp->tuple.dst.u.tcp.port)); | |
543 | ||
544 | return 0; | |
545 | } | |
546 | ||
547 | /****************************************************************************/ | |
548 | static int __init init(void) | |
549 | { | |
550 | BUG_ON(rcu_dereference(set_h245_addr_hook) != NULL); | |
551 | BUG_ON(rcu_dereference(set_h225_addr_hook) != NULL); | |
552 | BUG_ON(rcu_dereference(set_sig_addr_hook) != NULL); | |
553 | BUG_ON(rcu_dereference(set_ras_addr_hook) != NULL); | |
554 | BUG_ON(rcu_dereference(nat_rtp_rtcp_hook) != NULL); | |
555 | BUG_ON(rcu_dereference(nat_t120_hook) != NULL); | |
556 | BUG_ON(rcu_dereference(nat_h245_hook) != NULL); | |
557 | BUG_ON(rcu_dereference(nat_callforwarding_hook) != NULL); | |
558 | BUG_ON(rcu_dereference(nat_q931_hook) != NULL); | |
559 | ||
560 | rcu_assign_pointer(set_h245_addr_hook, set_h245_addr); | |
561 | rcu_assign_pointer(set_h225_addr_hook, set_h225_addr); | |
562 | rcu_assign_pointer(set_sig_addr_hook, set_sig_addr); | |
563 | rcu_assign_pointer(set_ras_addr_hook, set_ras_addr); | |
564 | rcu_assign_pointer(nat_rtp_rtcp_hook, nat_rtp_rtcp); | |
565 | rcu_assign_pointer(nat_t120_hook, nat_t120); | |
566 | rcu_assign_pointer(nat_h245_hook, nat_h245); | |
567 | rcu_assign_pointer(nat_callforwarding_hook, nat_callforwarding); | |
568 | rcu_assign_pointer(nat_q931_hook, nat_q931); | |
569 | ||
570 | DEBUGP("nf_nat_h323: init success\n"); | |
571 | return 0; | |
572 | } | |
573 | ||
574 | /****************************************************************************/ | |
575 | static void __exit fini(void) | |
576 | { | |
577 | rcu_assign_pointer(set_h245_addr_hook, NULL); | |
578 | rcu_assign_pointer(set_h225_addr_hook, NULL); | |
579 | rcu_assign_pointer(set_sig_addr_hook, NULL); | |
580 | rcu_assign_pointer(set_ras_addr_hook, NULL); | |
581 | rcu_assign_pointer(nat_rtp_rtcp_hook, NULL); | |
582 | rcu_assign_pointer(nat_t120_hook, NULL); | |
583 | rcu_assign_pointer(nat_h245_hook, NULL); | |
584 | rcu_assign_pointer(nat_callforwarding_hook, NULL); | |
585 | rcu_assign_pointer(nat_q931_hook, NULL); | |
586 | synchronize_rcu(); | |
587 | } | |
588 | ||
589 | /****************************************************************************/ | |
590 | module_init(init); | |
591 | module_exit(fini); | |
592 | ||
593 | MODULE_AUTHOR("Jing Min Zhao <zhaojingmin@users.sourceforge.net>"); | |
594 | MODULE_DESCRIPTION("H.323 NAT helper"); | |
595 | MODULE_LICENSE("GPL"); | |
596 | MODULE_ALIAS("ip_nat_h323"); |