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12#include <linux/module.h>
13#include <linux/tcp.h>
14#include <net/tcp.h>
15
16#include <net/netfilter/nf_nat.h>
17#include <net/netfilter/nf_nat_helper.h>
18#include <net/netfilter/nf_nat_rule.h>
19#include <net/netfilter/nf_conntrack_helper.h>
20#include <net/netfilter/nf_conntrack_expect.h>
21#include <linux/netfilter/nf_conntrack_h323.h>
22
23
24static int set_addr(struct sk_buff *skb,
25 unsigned char **data, int dataoff,
26 unsigned int addroff, __be32 ip, __be16 port)
27{
28 enum ip_conntrack_info ctinfo;
29 struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
30 struct {
31 __be32 ip;
32 __be16 port;
33 } __attribute__ ((__packed__)) buf;
34 const struct tcphdr *th;
35 struct tcphdr _tcph;
36
37 buf.ip = ip;
38 buf.port = port;
39 addroff += dataoff;
40
41 if (ip_hdr(skb)->protocol == IPPROTO_TCP) {
42 if (!nf_nat_mangle_tcp_packet(skb, ct, ctinfo,
43 addroff, sizeof(buf),
44 (char *) &buf, sizeof(buf))) {
45 if (net_ratelimit())
46 pr_notice("nf_nat_h323: nf_nat_mangle_tcp_packet"
47 " error\n");
48 return -1;
49 }
50
51
52 th = skb_header_pointer(skb, ip_hdrlen(skb),
53 sizeof(_tcph), &_tcph);
54 if (th == NULL)
55 return -1;
56 *data = skb->data + ip_hdrlen(skb) + th->doff * 4 + dataoff;
57 } else {
58 if (!nf_nat_mangle_udp_packet(skb, ct, ctinfo,
59 addroff, sizeof(buf),
60 (char *) &buf, sizeof(buf))) {
61 if (net_ratelimit())
62 pr_notice("nf_nat_h323: nf_nat_mangle_udp_packet"
63 " error\n");
64 return -1;
65 }
66
67
68
69 *data = skb->data + ip_hdrlen(skb) + sizeof(struct udphdr);
70 }
71
72 return 0;
73}
74
75
76static int set_h225_addr(struct sk_buff *skb,
77 unsigned char **data, int dataoff,
78 TransportAddress *taddr,
79 union nf_inet_addr *addr, __be16 port)
80{
81 return set_addr(skb, data, dataoff, taddr->ipAddress.ip,
82 addr->ip, port);
83}
84
85
86static int set_h245_addr(struct sk_buff *skb,
87 unsigned char **data, int dataoff,
88 H245_TransportAddress *taddr,
89 union nf_inet_addr *addr, __be16 port)
90{
91 return set_addr(skb, data, dataoff,
92 taddr->unicastAddress.iPAddress.network,
93 addr->ip, port);
94}
95
96
97static int set_sig_addr(struct sk_buff *skb, struct nf_conn *ct,
98 enum ip_conntrack_info ctinfo,
99 unsigned char **data,
100 TransportAddress *taddr, int count)
101{
102 const struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info;
103 int dir = CTINFO2DIR(ctinfo);
104 int i;
105 __be16 port;
106 union nf_inet_addr addr;
107
108 for (i = 0; i < count; i++) {
109 if (get_h225_addr(ct, *data, &taddr[i], &addr, &port)) {
110 if (addr.ip == ct->tuplehash[dir].tuple.src.u3.ip &&
111 port == info->sig_port[dir]) {
112
113
114
115 if (i > 0 &&
116 get_h225_addr(ct, *data, &taddr[0],
117 &addr, &port) &&
118 (ntohl(addr.ip) & 0xff000000) == 0x7f000000)
119 i = 0;
120
121 pr_debug("nf_nat_ras: set signal address %pI4:%hu->%pI4:%hu\n",
122 &addr.ip, port,
123 &ct->tuplehash[!dir].tuple.dst.u3.ip,
124 info->sig_port[!dir]);
125 return set_h225_addr(skb, data, 0, &taddr[i],
126 &ct->tuplehash[!dir].
127 tuple.dst.u3,
128 info->sig_port[!dir]);
129 } else if (addr.ip == ct->tuplehash[dir].tuple.dst.u3.ip &&
130 port == info->sig_port[dir]) {
131
132 pr_debug("nf_nat_ras: set signal address %pI4:%hu->%pI4:%hu\n",
133 &addr.ip, port,
134 &ct->tuplehash[!dir].tuple.src.u3.ip,
135 info->sig_port[!dir]);
136 return set_h225_addr(skb, data, 0, &taddr[i],
137 &ct->tuplehash[!dir].
138 tuple.src.u3,
139 info->sig_port[!dir]);
140 }
141 }
142 }
143
144 return 0;
145}
146
147
148static int set_ras_addr(struct sk_buff *skb, struct nf_conn *ct,
149 enum ip_conntrack_info ctinfo,
150 unsigned char **data,
151 TransportAddress *taddr, int count)
152{
153 int dir = CTINFO2DIR(ctinfo);
154 int i;
155 __be16 port;
156 union nf_inet_addr addr;
157
158 for (i = 0; i < count; i++) {
159 if (get_h225_addr(ct, *data, &taddr[i], &addr, &port) &&
160 addr.ip == ct->tuplehash[dir].tuple.src.u3.ip &&
161 port == ct->tuplehash[dir].tuple.src.u.udp.port) {
162 pr_debug("nf_nat_ras: set rasAddress %pI4:%hu->%pI4:%hu\n",
163 &addr.ip, ntohs(port),
164 &ct->tuplehash[!dir].tuple.dst.u3.ip,
165 ntohs(ct->tuplehash[!dir].tuple.dst.u.udp.port));
166 return set_h225_addr(skb, data, 0, &taddr[i],
167 &ct->tuplehash[!dir].tuple.dst.u3,
168 ct->tuplehash[!dir].tuple.
169 dst.u.udp.port);
170 }
171 }
172
173 return 0;
174}
175
176
177static int nat_rtp_rtcp(struct sk_buff *skb, struct nf_conn *ct,
178 enum ip_conntrack_info ctinfo,
179 unsigned char **data, int dataoff,
180 H245_TransportAddress *taddr,
181 __be16 port, __be16 rtp_port,
182 struct nf_conntrack_expect *rtp_exp,
183 struct nf_conntrack_expect *rtcp_exp)
184{
185 struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info;
186 int dir = CTINFO2DIR(ctinfo);
187 int i;
188 u_int16_t nated_port;
189
190
191 rtp_exp->saved_proto.udp.port = rtp_exp->tuple.dst.u.udp.port;
192 rtp_exp->expectfn = nf_nat_follow_master;
193 rtp_exp->dir = !dir;
194 rtcp_exp->saved_proto.udp.port = rtcp_exp->tuple.dst.u.udp.port;
195 rtcp_exp->expectfn = nf_nat_follow_master;
196 rtcp_exp->dir = !dir;
197
198
199 for (i = 0; i < H323_RTP_CHANNEL_MAX; i++) {
200 if (info->rtp_port[i][dir] == rtp_port) {
201
202
203
204
205 rtp_exp->tuple.dst.u.udp.port = info->rtp_port[i][dir];
206 rtcp_exp->tuple.dst.u.udp.port =
207 htons(ntohs(info->rtp_port[i][dir]) + 1);
208 break;
209 } else if (info->rtp_port[i][dir] == 0) {
210
211 break;
212 }
213 }
214
215
216 if (i >= H323_RTP_CHANNEL_MAX) {
217 if (net_ratelimit())
218 pr_notice("nf_nat_h323: out of expectations\n");
219 return 0;
220 }
221
222
223 for (nated_port = ntohs(rtp_exp->tuple.dst.u.udp.port);
224 nated_port != 0; nated_port += 2) {
225 int ret;
226
227 rtp_exp->tuple.dst.u.udp.port = htons(nated_port);
228 ret = nf_ct_expect_related(rtp_exp);
229 if (ret == 0) {
230 rtcp_exp->tuple.dst.u.udp.port =
231 htons(nated_port + 1);
232 ret = nf_ct_expect_related(rtcp_exp);
233 if (ret == 0)
234 break;
235 else if (ret != -EBUSY) {
236 nf_ct_unexpect_related(rtp_exp);
237 nated_port = 0;
238 break;
239 }
240 } else if (ret != -EBUSY) {
241 nated_port = 0;
242 break;
243 }
244 }
245
246 if (nated_port == 0) {
247 if (net_ratelimit())
248 pr_notice("nf_nat_h323: out of RTP ports\n");
249 return 0;
250 }
251
252
253 if (set_h245_addr(skb, data, dataoff, taddr,
254 &ct->tuplehash[!dir].tuple.dst.u3,
255 htons((port & htons(1)) ? nated_port + 1 :
256 nated_port)) == 0) {
257
258 info->rtp_port[i][dir] = rtp_port;
259 info->rtp_port[i][!dir] = htons(nated_port);
260 } else {
261 nf_ct_unexpect_related(rtp_exp);
262 nf_ct_unexpect_related(rtcp_exp);
263 return -1;
264 }
265
266
267 pr_debug("nf_nat_h323: expect RTP %pI4:%hu->%pI4:%hu\n",
268 &rtp_exp->tuple.src.u3.ip,
269 ntohs(rtp_exp->tuple.src.u.udp.port),
270 &rtp_exp->tuple.dst.u3.ip,
271 ntohs(rtp_exp->tuple.dst.u.udp.port));
272 pr_debug("nf_nat_h323: expect RTCP %pI4:%hu->%pI4:%hu\n",
273 &rtcp_exp->tuple.src.u3.ip,
274 ntohs(rtcp_exp->tuple.src.u.udp.port),
275 &rtcp_exp->tuple.dst.u3.ip,
276 ntohs(rtcp_exp->tuple.dst.u.udp.port));
277
278 return 0;
279}
280
281
282static int nat_t120(struct sk_buff *skb, struct nf_conn *ct,
283 enum ip_conntrack_info ctinfo,
284 unsigned char **data, int dataoff,
285 H245_TransportAddress *taddr, __be16 port,
286 struct nf_conntrack_expect *exp)
287{
288 int dir = CTINFO2DIR(ctinfo);
289 u_int16_t nated_port = ntohs(port);
290
291
292 exp->saved_proto.tcp.port = exp->tuple.dst.u.tcp.port;
293 exp->expectfn = nf_nat_follow_master;
294 exp->dir = !dir;
295
296
297 for (; nated_port != 0; nated_port++) {
298 int ret;
299
300 exp->tuple.dst.u.tcp.port = htons(nated_port);
301 ret = nf_ct_expect_related(exp);
302 if (ret == 0)
303 break;
304 else if (ret != -EBUSY) {
305 nated_port = 0;
306 break;
307 }
308 }
309
310 if (nated_port == 0) {
311 if (net_ratelimit())
312 pr_notice("nf_nat_h323: out of TCP ports\n");
313 return 0;
314 }
315
316
317 if (set_h245_addr(skb, data, dataoff, taddr,
318 &ct->tuplehash[!dir].tuple.dst.u3,
319 htons(nated_port)) < 0) {
320 nf_ct_unexpect_related(exp);
321 return -1;
322 }
323
324 pr_debug("nf_nat_h323: expect T.120 %pI4:%hu->%pI4:%hu\n",
325 &exp->tuple.src.u3.ip,
326 ntohs(exp->tuple.src.u.tcp.port),
327 &exp->tuple.dst.u3.ip,
328 ntohs(exp->tuple.dst.u.tcp.port));
329
330 return 0;
331}
332
333
334static int nat_h245(struct sk_buff *skb, struct nf_conn *ct,
335 enum ip_conntrack_info ctinfo,
336 unsigned char **data, int dataoff,
337 TransportAddress *taddr, __be16 port,
338 struct nf_conntrack_expect *exp)
339{
340 struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info;
341 int dir = CTINFO2DIR(ctinfo);
342 u_int16_t nated_port = ntohs(port);
343
344
345 exp->saved_proto.tcp.port = exp->tuple.dst.u.tcp.port;
346 exp->expectfn = nf_nat_follow_master;
347 exp->dir = !dir;
348
349
350 if (info->sig_port[dir] == port)
351 nated_port = ntohs(info->sig_port[!dir]);
352
353
354 for (; nated_port != 0; nated_port++) {
355 int ret;
356
357 exp->tuple.dst.u.tcp.port = htons(nated_port);
358 ret = nf_ct_expect_related(exp);
359 if (ret == 0)
360 break;
361 else if (ret != -EBUSY) {
362 nated_port = 0;
363 break;
364 }
365 }
366
367 if (nated_port == 0) {
368 if (net_ratelimit())
369 pr_notice("nf_nat_q931: out of TCP ports\n");
370 return 0;
371 }
372
373
374 if (set_h225_addr(skb, data, dataoff, taddr,
375 &ct->tuplehash[!dir].tuple.dst.u3,
376 htons(nated_port)) == 0) {
377
378 info->sig_port[dir] = port;
379 info->sig_port[!dir] = htons(nated_port);
380 } else {
381 nf_ct_unexpect_related(exp);
382 return -1;
383 }
384
385 pr_debug("nf_nat_q931: expect H.245 %pI4:%hu->%pI4:%hu\n",
386 &exp->tuple.src.u3.ip,
387 ntohs(exp->tuple.src.u.tcp.port),
388 &exp->tuple.dst.u3.ip,
389 ntohs(exp->tuple.dst.u.tcp.port));
390
391 return 0;
392}
393
394
395
396
397
398static void ip_nat_q931_expect(struct nf_conn *new,
399 struct nf_conntrack_expect *this)
400{
401 struct nf_nat_range range;
402
403 if (this->tuple.src.u3.ip != 0) {
404 nf_nat_follow_master(new, this);
405 return;
406 }
407
408
409 BUG_ON(new->status & IPS_NAT_DONE_MASK);
410
411
412 range.flags = IP_NAT_RANGE_MAP_IPS;
413 range.min_ip = range.max_ip = new->tuplehash[!this->dir].tuple.src.u3.ip;
414 nf_nat_setup_info(new, &range, IP_NAT_MANIP_SRC);
415
416
417 range.flags = (IP_NAT_RANGE_MAP_IPS | IP_NAT_RANGE_PROTO_SPECIFIED);
418 range.min = range.max = this->saved_proto;
419 range.min_ip = range.max_ip =
420 new->master->tuplehash[!this->dir].tuple.src.u3.ip;
421 nf_nat_setup_info(new, &range, IP_NAT_MANIP_DST);
422}
423
424
425static int nat_q931(struct sk_buff *skb, struct nf_conn *ct,
426 enum ip_conntrack_info ctinfo,
427 unsigned char **data, TransportAddress *taddr, int idx,
428 __be16 port, struct nf_conntrack_expect *exp)
429{
430 struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info;
431 int dir = CTINFO2DIR(ctinfo);
432 u_int16_t nated_port = ntohs(port);
433 union nf_inet_addr addr;
434
435
436 exp->saved_proto.tcp.port = exp->tuple.dst.u.tcp.port;
437 exp->expectfn = ip_nat_q931_expect;
438 exp->dir = !dir;
439
440
441 if (info->sig_port[dir] == port)
442 nated_port = ntohs(info->sig_port[!dir]);
443
444
445 for (; nated_port != 0; nated_port++) {
446 int ret;
447
448 exp->tuple.dst.u.tcp.port = htons(nated_port);
449 ret = nf_ct_expect_related(exp);
450 if (ret == 0)
451 break;
452 else if (ret != -EBUSY) {
453 nated_port = 0;
454 break;
455 }
456 }
457
458 if (nated_port == 0) {
459 if (net_ratelimit())
460 pr_notice("nf_nat_ras: out of TCP ports\n");
461 return 0;
462 }
463
464
465 if (set_h225_addr(skb, data, 0, &taddr[idx],
466 &ct->tuplehash[!dir].tuple.dst.u3,
467 htons(nated_port)) == 0) {
468
469 info->sig_port[dir] = port;
470 info->sig_port[!dir] = htons(nated_port);
471
472
473 if (idx > 0 &&
474 get_h225_addr(ct, *data, &taddr[0], &addr, &port) &&
475 (ntohl(addr.ip) & 0xff000000) == 0x7f000000) {
476 set_h225_addr(skb, data, 0, &taddr[0],
477 &ct->tuplehash[!dir].tuple.dst.u3,
478 info->sig_port[!dir]);
479 }
480 } else {
481 nf_ct_unexpect_related(exp);
482 return -1;
483 }
484
485
486 pr_debug("nf_nat_ras: expect Q.931 %pI4:%hu->%pI4:%hu\n",
487 &exp->tuple.src.u3.ip,
488 ntohs(exp->tuple.src.u.tcp.port),
489 &exp->tuple.dst.u3.ip,
490 ntohs(exp->tuple.dst.u.tcp.port));
491
492 return 0;
493}
494
495
496static void ip_nat_callforwarding_expect(struct nf_conn *new,
497 struct nf_conntrack_expect *this)
498{
499 struct nf_nat_range range;
500
501
502 BUG_ON(new->status & IPS_NAT_DONE_MASK);
503
504
505 range.flags = IP_NAT_RANGE_MAP_IPS;
506 range.min_ip = range.max_ip = new->tuplehash[!this->dir].tuple.src.u3.ip;
507 nf_nat_setup_info(new, &range, IP_NAT_MANIP_SRC);
508
509
510 range.flags = (IP_NAT_RANGE_MAP_IPS | IP_NAT_RANGE_PROTO_SPECIFIED);
511 range.min = range.max = this->saved_proto;
512 range.min_ip = range.max_ip = this->saved_ip;
513 nf_nat_setup_info(new, &range, IP_NAT_MANIP_DST);
514}
515
516
517static int nat_callforwarding(struct sk_buff *skb, struct nf_conn *ct,
518 enum ip_conntrack_info ctinfo,
519 unsigned char **data, int dataoff,
520 TransportAddress *taddr, __be16 port,
521 struct nf_conntrack_expect *exp)
522{
523 int dir = CTINFO2DIR(ctinfo);
524 u_int16_t nated_port;
525
526
527 exp->saved_ip = exp->tuple.dst.u3.ip;
528 exp->tuple.dst.u3.ip = ct->tuplehash[!dir].tuple.dst.u3.ip;
529 exp->saved_proto.tcp.port = exp->tuple.dst.u.tcp.port;
530 exp->expectfn = ip_nat_callforwarding_expect;
531 exp->dir = !dir;
532
533
534 for (nated_port = ntohs(port); nated_port != 0; nated_port++) {
535 int ret;
536
537 exp->tuple.dst.u.tcp.port = htons(nated_port);
538 ret = nf_ct_expect_related(exp);
539 if (ret == 0)
540 break;
541 else if (ret != -EBUSY) {
542 nated_port = 0;
543 break;
544 }
545 }
546
547 if (nated_port == 0) {
548 if (net_ratelimit())
549 pr_notice("nf_nat_q931: out of TCP ports\n");
550 return 0;
551 }
552
553
554 if (!set_h225_addr(skb, data, dataoff, taddr,
555 &ct->tuplehash[!dir].tuple.dst.u3,
556 htons(nated_port)) == 0) {
557 nf_ct_unexpect_related(exp);
558 return -1;
559 }
560
561
562 pr_debug("nf_nat_q931: expect Call Forwarding %pI4:%hu->%pI4:%hu\n",
563 &exp->tuple.src.u3.ip,
564 ntohs(exp->tuple.src.u.tcp.port),
565 &exp->tuple.dst.u3.ip,
566 ntohs(exp->tuple.dst.u.tcp.port));
567
568 return 0;
569}
570
571
572static int __init init(void)
573{
574 BUG_ON(set_h245_addr_hook != NULL);
575 BUG_ON(set_h225_addr_hook != NULL);
576 BUG_ON(set_sig_addr_hook != NULL);
577 BUG_ON(set_ras_addr_hook != NULL);
578 BUG_ON(nat_rtp_rtcp_hook != NULL);
579 BUG_ON(nat_t120_hook != NULL);
580 BUG_ON(nat_h245_hook != NULL);
581 BUG_ON(nat_callforwarding_hook != NULL);
582 BUG_ON(nat_q931_hook != NULL);
583
584 RCU_INIT_POINTER(set_h245_addr_hook, set_h245_addr);
585 RCU_INIT_POINTER(set_h225_addr_hook, set_h225_addr);
586 RCU_INIT_POINTER(set_sig_addr_hook, set_sig_addr);
587 RCU_INIT_POINTER(set_ras_addr_hook, set_ras_addr);
588 RCU_INIT_POINTER(nat_rtp_rtcp_hook, nat_rtp_rtcp);
589 RCU_INIT_POINTER(nat_t120_hook, nat_t120);
590 RCU_INIT_POINTER(nat_h245_hook, nat_h245);
591 RCU_INIT_POINTER(nat_callforwarding_hook, nat_callforwarding);
592 RCU_INIT_POINTER(nat_q931_hook, nat_q931);
593 return 0;
594}
595
596
597static void __exit fini(void)
598{
599 RCU_INIT_POINTER(set_h245_addr_hook, NULL);
600 RCU_INIT_POINTER(set_h225_addr_hook, NULL);
601 RCU_INIT_POINTER(set_sig_addr_hook, NULL);
602 RCU_INIT_POINTER(set_ras_addr_hook, NULL);
603 RCU_INIT_POINTER(nat_rtp_rtcp_hook, NULL);
604 RCU_INIT_POINTER(nat_t120_hook, NULL);
605 RCU_INIT_POINTER(nat_h245_hook, NULL);
606 RCU_INIT_POINTER(nat_callforwarding_hook, NULL);
607 RCU_INIT_POINTER(nat_q931_hook, NULL);
608 synchronize_rcu();
609}
610
611
612module_init(init);
613module_exit(fini);
614
615MODULE_AUTHOR("Jing Min Zhao <zhaojingmin@users.sourceforge.net>");
616MODULE_DESCRIPTION("H.323 NAT helper");
617MODULE_LICENSE("GPL");
618MODULE_ALIAS("ip_nat_h323");
619
