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 /****************************************************************************/
set_addr(struct sk_buff * skb,unsigned char ** data,int dataoff,unsigned int addroff,__be32 ip,__be16 port)25 static int set_addr(struct sk_buff *skb,
26 unsigned char **data, int dataoff,
27 unsigned int addroff, __be32 ip, __be16 port)
28 {
29 enum ip_conntrack_info ctinfo;
30 struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
31 struct {
32 __be32 ip;
33 __be16 port;
34 } __attribute__ ((__packed__)) buf;
35 const struct tcphdr *th;
36 struct tcphdr _tcph;
37
38 buf.ip = ip;
39 buf.port = port;
40 addroff += dataoff;
41
42 if (ip_hdr(skb)->protocol == IPPROTO_TCP) {
43 if (!nf_nat_mangle_tcp_packet(skb, ct, ctinfo,
44 addroff, sizeof(buf),
45 (char *) &buf, sizeof(buf))) {
46 if (net_ratelimit())
47 printk("nf_nat_h323: nf_nat_mangle_tcp_packet"
48 " error\n");
49 return -1;
50 }
51
52 /* Relocate data pointer */
53 th = skb_header_pointer(skb, ip_hdrlen(skb),
54 sizeof(_tcph), &_tcph);
55 if (th == NULL)
56 return -1;
57 *data = skb->data + ip_hdrlen(skb) + th->doff * 4 + dataoff;
58 } else {
59 if (!nf_nat_mangle_udp_packet(skb, ct, ctinfo,
60 addroff, sizeof(buf),
61 (char *) &buf, sizeof(buf))) {
62 if (net_ratelimit())
63 printk("nf_nat_h323: nf_nat_mangle_udp_packet"
64 " error\n");
65 return -1;
66 }
67 /* nf_nat_mangle_udp_packet uses skb_make_writable() to copy
68 * or pull everything in a linear buffer, so we can safely
69 * use the skb pointers now */
70 *data = skb->data + ip_hdrlen(skb) + sizeof(struct udphdr);
71 }
72
73 return 0;
74 }
75
76 /****************************************************************************/
set_h225_addr(struct sk_buff * skb,unsigned char ** data,int dataoff,TransportAddress * taddr,union nf_inet_addr * addr,__be16 port)77 static int set_h225_addr(struct sk_buff *skb,
78 unsigned char **data, int dataoff,
79 TransportAddress *taddr,
80 union nf_inet_addr *addr, __be16 port)
81 {
82 return set_addr(skb, data, dataoff, taddr->ipAddress.ip,
83 addr->ip, port);
84 }
85
86 /****************************************************************************/
set_h245_addr(struct sk_buff * skb,unsigned char ** data,int dataoff,H245_TransportAddress * taddr,union nf_inet_addr * addr,__be16 port)87 static int set_h245_addr(struct sk_buff *skb,
88 unsigned char **data, int dataoff,
89 H245_TransportAddress *taddr,
90 union nf_inet_addr *addr, __be16 port)
91 {
92 return set_addr(skb, data, dataoff,
93 taddr->unicastAddress.iPAddress.network,
94 addr->ip, port);
95 }
96
97 /****************************************************************************/
set_sig_addr(struct sk_buff * skb,struct nf_conn * ct,enum ip_conntrack_info ctinfo,unsigned char ** data,TransportAddress * taddr,int count)98 static int set_sig_addr(struct sk_buff *skb, struct nf_conn *ct,
99 enum ip_conntrack_info ctinfo,
100 unsigned char **data,
101 TransportAddress *taddr, int count)
102 {
103 const struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info;
104 int dir = CTINFO2DIR(ctinfo);
105 int i;
106 __be16 port;
107 union nf_inet_addr addr;
108
109 for (i = 0; i < count; i++) {
110 if (get_h225_addr(ct, *data, &taddr[i], &addr, &port)) {
111 if (addr.ip == ct->tuplehash[dir].tuple.src.u3.ip &&
112 port == info->sig_port[dir]) {
113 /* GW->GK */
114
115 /* Fix for Gnomemeeting */
116 if (i > 0 &&
117 get_h225_addr(ct, *data, &taddr[0],
118 &addr, &port) &&
119 (ntohl(addr.ip) & 0xff000000) == 0x7f000000)
120 i = 0;
121
122 pr_debug("nf_nat_ras: set signal address %pI4:%hu->%pI4:%hu\n",
123 &addr.ip, port,
124 &ct->tuplehash[!dir].tuple.dst.u3.ip,
125 info->sig_port[!dir]);
126 return set_h225_addr(skb, data, 0, &taddr[i],
127 &ct->tuplehash[!dir].
128 tuple.dst.u3,
129 info->sig_port[!dir]);
130 } else if (addr.ip == ct->tuplehash[dir].tuple.dst.u3.ip &&
131 port == info->sig_port[dir]) {
132 /* GK->GW */
133 pr_debug("nf_nat_ras: set signal address %pI4:%hu->%pI4:%hu\n",
134 &addr.ip, port,
135 &ct->tuplehash[!dir].tuple.src.u3.ip,
136 info->sig_port[!dir]);
137 return set_h225_addr(skb, data, 0, &taddr[i],
138 &ct->tuplehash[!dir].
139 tuple.src.u3,
140 info->sig_port[!dir]);
141 }
142 }
143 }
144
145 return 0;
146 }
147
148 /****************************************************************************/
set_ras_addr(struct sk_buff * skb,struct nf_conn * ct,enum ip_conntrack_info ctinfo,unsigned char ** data,TransportAddress * taddr,int count)149 static int set_ras_addr(struct sk_buff *skb, struct nf_conn *ct,
150 enum ip_conntrack_info ctinfo,
151 unsigned char **data,
152 TransportAddress *taddr, int count)
153 {
154 int dir = CTINFO2DIR(ctinfo);
155 int i;
156 __be16 port;
157 union nf_inet_addr addr;
158
159 for (i = 0; i < count; i++) {
160 if (get_h225_addr(ct, *data, &taddr[i], &addr, &port) &&
161 addr.ip == ct->tuplehash[dir].tuple.src.u3.ip &&
162 port == ct->tuplehash[dir].tuple.src.u.udp.port) {
163 pr_debug("nf_nat_ras: set rasAddress %pI4:%hu->%pI4:%hu\n",
164 &addr.ip, ntohs(port),
165 &ct->tuplehash[!dir].tuple.dst.u3.ip,
166 ntohs(ct->tuplehash[!dir].tuple.dst.u.udp.port));
167 return set_h225_addr(skb, data, 0, &taddr[i],
168 &ct->tuplehash[!dir].tuple.dst.u3,
169 ct->tuplehash[!dir].tuple.
170 dst.u.udp.port);
171 }
172 }
173
174 return 0;
175 }
176
177 /****************************************************************************/
nat_rtp_rtcp(struct sk_buff * skb,struct nf_conn * ct,enum ip_conntrack_info ctinfo,unsigned char ** data,int dataoff,H245_TransportAddress * taddr,__be16 port,__be16 rtp_port,struct nf_conntrack_expect * rtp_exp,struct nf_conntrack_expect * rtcp_exp)178 static int nat_rtp_rtcp(struct sk_buff *skb, struct nf_conn *ct,
179 enum ip_conntrack_info ctinfo,
180 unsigned char **data, int dataoff,
181 H245_TransportAddress *taddr,
182 __be16 port, __be16 rtp_port,
183 struct nf_conntrack_expect *rtp_exp,
184 struct nf_conntrack_expect *rtcp_exp)
185 {
186 struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info;
187 int dir = CTINFO2DIR(ctinfo);
188 int i;
189 u_int16_t nated_port;
190
191 /* Set expectations for NAT */
192 rtp_exp->saved_proto.udp.port = rtp_exp->tuple.dst.u.udp.port;
193 rtp_exp->expectfn = nf_nat_follow_master;
194 rtp_exp->dir = !dir;
195 rtcp_exp->saved_proto.udp.port = rtcp_exp->tuple.dst.u.udp.port;
196 rtcp_exp->expectfn = nf_nat_follow_master;
197 rtcp_exp->dir = !dir;
198
199 /* Lookup existing expects */
200 for (i = 0; i < H323_RTP_CHANNEL_MAX; i++) {
201 if (info->rtp_port[i][dir] == rtp_port) {
202 /* Expected */
203
204 /* Use allocated ports first. This will refresh
205 * the expects */
206 rtp_exp->tuple.dst.u.udp.port = info->rtp_port[i][dir];
207 rtcp_exp->tuple.dst.u.udp.port =
208 htons(ntohs(info->rtp_port[i][dir]) + 1);
209 break;
210 } else if (info->rtp_port[i][dir] == 0) {
211 /* Not expected */
212 break;
213 }
214 }
215
216 /* Run out of expectations */
217 if (i >= H323_RTP_CHANNEL_MAX) {
218 if (net_ratelimit())
219 printk("nf_nat_h323: out of expectations\n");
220 return 0;
221 }
222
223 /* Try to get a pair of ports. */
224 for (nated_port = ntohs(rtp_exp->tuple.dst.u.udp.port);
225 nated_port != 0; nated_port += 2) {
226 rtp_exp->tuple.dst.u.udp.port = htons(nated_port);
227 if (nf_ct_expect_related(rtp_exp) == 0) {
228 rtcp_exp->tuple.dst.u.udp.port =
229 htons(nated_port + 1);
230 if (nf_ct_expect_related(rtcp_exp) == 0)
231 break;
232 nf_ct_unexpect_related(rtp_exp);
233 }
234 }
235
236 if (nated_port == 0) { /* No port available */
237 if (net_ratelimit())
238 printk("nf_nat_h323: out of RTP ports\n");
239 return 0;
240 }
241
242 /* Modify signal */
243 if (set_h245_addr(skb, data, dataoff, taddr,
244 &ct->tuplehash[!dir].tuple.dst.u3,
245 htons((port & htons(1)) ? nated_port + 1 :
246 nated_port)) == 0) {
247 /* Save ports */
248 info->rtp_port[i][dir] = rtp_port;
249 info->rtp_port[i][!dir] = htons(nated_port);
250 } else {
251 nf_ct_unexpect_related(rtp_exp);
252 nf_ct_unexpect_related(rtcp_exp);
253 return -1;
254 }
255
256 /* Success */
257 pr_debug("nf_nat_h323: expect RTP %pI4:%hu->%pI4:%hu\n",
258 &rtp_exp->tuple.src.u3.ip,
259 ntohs(rtp_exp->tuple.src.u.udp.port),
260 &rtp_exp->tuple.dst.u3.ip,
261 ntohs(rtp_exp->tuple.dst.u.udp.port));
262 pr_debug("nf_nat_h323: expect RTCP %pI4:%hu->%pI4:%hu\n",
263 &rtcp_exp->tuple.src.u3.ip,
264 ntohs(rtcp_exp->tuple.src.u.udp.port),
265 &rtcp_exp->tuple.dst.u3.ip,
266 ntohs(rtcp_exp->tuple.dst.u.udp.port));
267
268 return 0;
269 }
270
271 /****************************************************************************/
nat_t120(struct sk_buff * skb,struct nf_conn * ct,enum ip_conntrack_info ctinfo,unsigned char ** data,int dataoff,H245_TransportAddress * taddr,__be16 port,struct nf_conntrack_expect * exp)272 static int nat_t120(struct sk_buff *skb, struct nf_conn *ct,
273 enum ip_conntrack_info ctinfo,
274 unsigned char **data, int dataoff,
275 H245_TransportAddress *taddr, __be16 port,
276 struct nf_conntrack_expect *exp)
277 {
278 int dir = CTINFO2DIR(ctinfo);
279 u_int16_t nated_port = ntohs(port);
280
281 /* Set expectations for NAT */
282 exp->saved_proto.tcp.port = exp->tuple.dst.u.tcp.port;
283 exp->expectfn = nf_nat_follow_master;
284 exp->dir = !dir;
285
286 /* Try to get same port: if not, try to change it. */
287 for (; nated_port != 0; nated_port++) {
288 exp->tuple.dst.u.tcp.port = htons(nated_port);
289 if (nf_ct_expect_related(exp) == 0)
290 break;
291 }
292
293 if (nated_port == 0) { /* No port available */
294 if (net_ratelimit())
295 printk("nf_nat_h323: out of TCP ports\n");
296 return 0;
297 }
298
299 /* Modify signal */
300 if (set_h245_addr(skb, data, dataoff, taddr,
301 &ct->tuplehash[!dir].tuple.dst.u3,
302 htons(nated_port)) < 0) {
303 nf_ct_unexpect_related(exp);
304 return -1;
305 }
306
307 pr_debug("nf_nat_h323: expect T.120 %pI4:%hu->%pI4:%hu\n",
308 &exp->tuple.src.u3.ip,
309 ntohs(exp->tuple.src.u.tcp.port),
310 &exp->tuple.dst.u3.ip,
311 ntohs(exp->tuple.dst.u.tcp.port));
312
313 return 0;
314 }
315
316 /****************************************************************************/
nat_h245(struct sk_buff * skb,struct nf_conn * ct,enum ip_conntrack_info ctinfo,unsigned char ** data,int dataoff,TransportAddress * taddr,__be16 port,struct nf_conntrack_expect * exp)317 static int nat_h245(struct sk_buff *skb, struct nf_conn *ct,
318 enum ip_conntrack_info ctinfo,
319 unsigned char **data, int dataoff,
320 TransportAddress *taddr, __be16 port,
321 struct nf_conntrack_expect *exp)
322 {
323 struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info;
324 int dir = CTINFO2DIR(ctinfo);
325 u_int16_t nated_port = ntohs(port);
326
327 /* Set expectations for NAT */
328 exp->saved_proto.tcp.port = exp->tuple.dst.u.tcp.port;
329 exp->expectfn = nf_nat_follow_master;
330 exp->dir = !dir;
331
332 /* Check existing expects */
333 if (info->sig_port[dir] == port)
334 nated_port = ntohs(info->sig_port[!dir]);
335
336 /* Try to get same port: if not, try to change it. */
337 for (; nated_port != 0; nated_port++) {
338 exp->tuple.dst.u.tcp.port = htons(nated_port);
339 if (nf_ct_expect_related(exp) == 0)
340 break;
341 }
342
343 if (nated_port == 0) { /* No port available */
344 if (net_ratelimit())
345 printk("nf_nat_q931: out of TCP ports\n");
346 return 0;
347 }
348
349 /* Modify signal */
350 if (set_h225_addr(skb, data, dataoff, taddr,
351 &ct->tuplehash[!dir].tuple.dst.u3,
352 htons(nated_port)) == 0) {
353 /* Save ports */
354 info->sig_port[dir] = port;
355 info->sig_port[!dir] = htons(nated_port);
356 } else {
357 nf_ct_unexpect_related(exp);
358 return -1;
359 }
360
361 pr_debug("nf_nat_q931: expect H.245 %pI4:%hu->%pI4:%hu\n",
362 &exp->tuple.src.u3.ip,
363 ntohs(exp->tuple.src.u.tcp.port),
364 &exp->tuple.dst.u3.ip,
365 ntohs(exp->tuple.dst.u.tcp.port));
366
367 return 0;
368 }
369
370 /****************************************************************************
371 * This conntrack expect function replaces nf_conntrack_q931_expect()
372 * which was set by nf_conntrack_h323.c.
373 ****************************************************************************/
ip_nat_q931_expect(struct nf_conn * new,struct nf_conntrack_expect * this)374 static void ip_nat_q931_expect(struct nf_conn *new,
375 struct nf_conntrack_expect *this)
376 {
377 struct nf_nat_range range;
378
379 if (this->tuple.src.u3.ip != 0) { /* Only accept calls from GK */
380 nf_nat_follow_master(new, this);
381 return;
382 }
383
384 /* This must be a fresh one. */
385 BUG_ON(new->status & IPS_NAT_DONE_MASK);
386
387 /* Change src to where master sends to */
388 range.flags = IP_NAT_RANGE_MAP_IPS;
389 range.min_ip = range.max_ip = new->tuplehash[!this->dir].tuple.src.u3.ip;
390 nf_nat_setup_info(new, &range, IP_NAT_MANIP_SRC);
391
392 /* For DST manip, map port here to where it's expected. */
393 range.flags = (IP_NAT_RANGE_MAP_IPS | IP_NAT_RANGE_PROTO_SPECIFIED);
394 range.min = range.max = this->saved_proto;
395 range.min_ip = range.max_ip =
396 new->master->tuplehash[!this->dir].tuple.src.u3.ip;
397 nf_nat_setup_info(new, &range, IP_NAT_MANIP_DST);
398 }
399
400 /****************************************************************************/
nat_q931(struct sk_buff * skb,struct nf_conn * ct,enum ip_conntrack_info ctinfo,unsigned char ** data,TransportAddress * taddr,int idx,__be16 port,struct nf_conntrack_expect * exp)401 static int nat_q931(struct sk_buff *skb, struct nf_conn *ct,
402 enum ip_conntrack_info ctinfo,
403 unsigned char **data, TransportAddress *taddr, int idx,
404 __be16 port, struct nf_conntrack_expect *exp)
405 {
406 struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info;
407 int dir = CTINFO2DIR(ctinfo);
408 u_int16_t nated_port = ntohs(port);
409 union nf_inet_addr addr;
410
411 /* Set expectations for NAT */
412 exp->saved_proto.tcp.port = exp->tuple.dst.u.tcp.port;
413 exp->expectfn = ip_nat_q931_expect;
414 exp->dir = !dir;
415
416 /* Check existing expects */
417 if (info->sig_port[dir] == port)
418 nated_port = ntohs(info->sig_port[!dir]);
419
420 /* Try to get same port: if not, try to change it. */
421 for (; nated_port != 0; nated_port++) {
422 exp->tuple.dst.u.tcp.port = htons(nated_port);
423 if (nf_ct_expect_related(exp) == 0)
424 break;
425 }
426
427 if (nated_port == 0) { /* No port available */
428 if (net_ratelimit())
429 printk("nf_nat_ras: out of TCP ports\n");
430 return 0;
431 }
432
433 /* Modify signal */
434 if (set_h225_addr(skb, data, 0, &taddr[idx],
435 &ct->tuplehash[!dir].tuple.dst.u3,
436 htons(nated_port)) == 0) {
437 /* Save ports */
438 info->sig_port[dir] = port;
439 info->sig_port[!dir] = htons(nated_port);
440
441 /* Fix for Gnomemeeting */
442 if (idx > 0 &&
443 get_h225_addr(ct, *data, &taddr[0], &addr, &port) &&
444 (ntohl(addr.ip) & 0xff000000) == 0x7f000000) {
445 set_h225_addr(skb, data, 0, &taddr[0],
446 &ct->tuplehash[!dir].tuple.dst.u3,
447 info->sig_port[!dir]);
448 }
449 } else {
450 nf_ct_unexpect_related(exp);
451 return -1;
452 }
453
454 /* Success */
455 pr_debug("nf_nat_ras: expect Q.931 %pI4:%hu->%pI4:%hu\n",
456 &exp->tuple.src.u3.ip,
457 ntohs(exp->tuple.src.u.tcp.port),
458 &exp->tuple.dst.u3.ip,
459 ntohs(exp->tuple.dst.u.tcp.port));
460
461 return 0;
462 }
463
464 /****************************************************************************/
ip_nat_callforwarding_expect(struct nf_conn * new,struct nf_conntrack_expect * this)465 static void ip_nat_callforwarding_expect(struct nf_conn *new,
466 struct nf_conntrack_expect *this)
467 {
468 struct nf_nat_range range;
469
470 /* This must be a fresh one. */
471 BUG_ON(new->status & IPS_NAT_DONE_MASK);
472
473 /* Change src to where master sends to */
474 range.flags = IP_NAT_RANGE_MAP_IPS;
475 range.min_ip = range.max_ip = new->tuplehash[!this->dir].tuple.src.u3.ip;
476 nf_nat_setup_info(new, &range, IP_NAT_MANIP_SRC);
477
478 /* For DST manip, map port here to where it's expected. */
479 range.flags = (IP_NAT_RANGE_MAP_IPS | IP_NAT_RANGE_PROTO_SPECIFIED);
480 range.min = range.max = this->saved_proto;
481 range.min_ip = range.max_ip = this->saved_ip;
482 nf_nat_setup_info(new, &range, IP_NAT_MANIP_DST);
483 }
484
485 /****************************************************************************/
nat_callforwarding(struct sk_buff * skb,struct nf_conn * ct,enum ip_conntrack_info ctinfo,unsigned char ** data,int dataoff,TransportAddress * taddr,__be16 port,struct nf_conntrack_expect * exp)486 static int nat_callforwarding(struct sk_buff *skb, struct nf_conn *ct,
487 enum ip_conntrack_info ctinfo,
488 unsigned char **data, int dataoff,
489 TransportAddress *taddr, __be16 port,
490 struct nf_conntrack_expect *exp)
491 {
492 int dir = CTINFO2DIR(ctinfo);
493 u_int16_t nated_port;
494
495 /* Set expectations for NAT */
496 exp->saved_ip = exp->tuple.dst.u3.ip;
497 exp->tuple.dst.u3.ip = ct->tuplehash[!dir].tuple.dst.u3.ip;
498 exp->saved_proto.tcp.port = exp->tuple.dst.u.tcp.port;
499 exp->expectfn = ip_nat_callforwarding_expect;
500 exp->dir = !dir;
501
502 /* Try to get same port: if not, try to change it. */
503 for (nated_port = ntohs(port); nated_port != 0; nated_port++) {
504 exp->tuple.dst.u.tcp.port = htons(nated_port);
505 if (nf_ct_expect_related(exp) == 0)
506 break;
507 }
508
509 if (nated_port == 0) { /* No port available */
510 if (net_ratelimit())
511 printk("nf_nat_q931: out of TCP ports\n");
512 return 0;
513 }
514
515 /* Modify signal */
516 if (!set_h225_addr(skb, data, dataoff, taddr,
517 &ct->tuplehash[!dir].tuple.dst.u3,
518 htons(nated_port)) == 0) {
519 nf_ct_unexpect_related(exp);
520 return -1;
521 }
522
523 /* Success */
524 pr_debug("nf_nat_q931: expect Call Forwarding %pI4:%hu->%pI4:%hu\n",
525 &exp->tuple.src.u3.ip,
526 ntohs(exp->tuple.src.u.tcp.port),
527 &exp->tuple.dst.u3.ip,
528 ntohs(exp->tuple.dst.u.tcp.port));
529
530 return 0;
531 }
532
533 /****************************************************************************/
init(void)534 static int __init init(void)
535 {
536 BUG_ON(set_h245_addr_hook != NULL);
537 BUG_ON(set_h225_addr_hook != NULL);
538 BUG_ON(set_sig_addr_hook != NULL);
539 BUG_ON(set_ras_addr_hook != NULL);
540 BUG_ON(nat_rtp_rtcp_hook != NULL);
541 BUG_ON(nat_t120_hook != NULL);
542 BUG_ON(nat_h245_hook != NULL);
543 BUG_ON(nat_callforwarding_hook != NULL);
544 BUG_ON(nat_q931_hook != NULL);
545
546 rcu_assign_pointer(set_h245_addr_hook, set_h245_addr);
547 rcu_assign_pointer(set_h225_addr_hook, set_h225_addr);
548 rcu_assign_pointer(set_sig_addr_hook, set_sig_addr);
549 rcu_assign_pointer(set_ras_addr_hook, set_ras_addr);
550 rcu_assign_pointer(nat_rtp_rtcp_hook, nat_rtp_rtcp);
551 rcu_assign_pointer(nat_t120_hook, nat_t120);
552 rcu_assign_pointer(nat_h245_hook, nat_h245);
553 rcu_assign_pointer(nat_callforwarding_hook, nat_callforwarding);
554 rcu_assign_pointer(nat_q931_hook, nat_q931);
555 return 0;
556 }
557
558 /****************************************************************************/
fini(void)559 static void __exit fini(void)
560 {
561 rcu_assign_pointer(set_h245_addr_hook, NULL);
562 rcu_assign_pointer(set_h225_addr_hook, NULL);
563 rcu_assign_pointer(set_sig_addr_hook, NULL);
564 rcu_assign_pointer(set_ras_addr_hook, NULL);
565 rcu_assign_pointer(nat_rtp_rtcp_hook, NULL);
566 rcu_assign_pointer(nat_t120_hook, NULL);
567 rcu_assign_pointer(nat_h245_hook, NULL);
568 rcu_assign_pointer(nat_callforwarding_hook, NULL);
569 rcu_assign_pointer(nat_q931_hook, NULL);
570 synchronize_rcu();
571 }
572
573 /****************************************************************************/
574 module_init(init);
575 module_exit(fini);
576
577 MODULE_AUTHOR("Jing Min Zhao <zhaojingmin@users.sourceforge.net>");
578 MODULE_DESCRIPTION("H.323 NAT helper");
579 MODULE_LICENSE("GPL");
580 MODULE_ALIAS("ip_nat_h323");
581