1/* 2 * H.323 extension for NAT alteration. 3 * 4 * Copyright (c) 2006 Jing Min Zhao <zhaojingmin@users.sourceforge.net> 5 * Copyright (c) 2006-2012 Patrick McHardy <kaber@trash.net> 6 * 7 * This source code is licensed under General Public License version 2. 8 * 9 * Based on the 'brute force' H.323 NAT module by 10 * Jozsef Kadlecsik <kadlec@blackhole.kfki.hu> 11 */ 12 13#include <linux/module.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_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, unsigned int protoff, 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 protoff, addroff, sizeof(buf), 44 (char *) &buf, sizeof(buf))) { 45 net_notice_ratelimited("nf_nat_h323: nf_nat_mangle_tcp_packet error\n"); 46 return -1; 47 } 48 49 /* Relocate data pointer */ 50 th = skb_header_pointer(skb, ip_hdrlen(skb), 51 sizeof(_tcph), &_tcph); 52 if (th == NULL) 53 return -1; 54 *data = skb->data + ip_hdrlen(skb) + th->doff * 4 + dataoff; 55 } else { 56 if (!nf_nat_mangle_udp_packet(skb, ct, ctinfo, 57 protoff, addroff, sizeof(buf), 58 (char *) &buf, sizeof(buf))) { 59 net_notice_ratelimited("nf_nat_h323: nf_nat_mangle_udp_packet error\n"); 60 return -1; 61 } 62 /* nf_nat_mangle_udp_packet uses skb_make_writable() to copy 63 * or pull everything in a linear buffer, so we can safely 64 * use the skb pointers now */ 65 *data = skb->data + ip_hdrlen(skb) + sizeof(struct udphdr); 66 } 67 68 return 0; 69} 70 71/****************************************************************************/ 72static int set_h225_addr(struct sk_buff *skb, unsigned int protoff, 73 unsigned char **data, int dataoff, 74 TransportAddress *taddr, 75 union nf_inet_addr *addr, __be16 port) 76{ 77 return set_addr(skb, protoff, data, dataoff, taddr->ipAddress.ip, 78 addr->ip, port); 79} 80 81/****************************************************************************/ 82static int set_h245_addr(struct sk_buff *skb, unsigned protoff, 83 unsigned char **data, int dataoff, 84 H245_TransportAddress *taddr, 85 union nf_inet_addr *addr, __be16 port) 86{ 87 return set_addr(skb, protoff, data, dataoff, 88 taddr->unicastAddress.iPAddress.network, 89 addr->ip, port); 90} 91 92/****************************************************************************/ 93static int set_sig_addr(struct sk_buff *skb, struct nf_conn *ct, 94 enum ip_conntrack_info ctinfo, 95 unsigned int protoff, unsigned char **data, 96 TransportAddress *taddr, int count) 97{ 98 const struct nf_ct_h323_master *info = nfct_help_data(ct); 99 int dir = CTINFO2DIR(ctinfo); 100 int i; 101 __be16 port; 102 union nf_inet_addr addr; 103 104 for (i = 0; i < count; i++) { 105 if (get_h225_addr(ct, *data, &taddr[i], &addr, &port)) { 106 if (addr.ip == ct->tuplehash[dir].tuple.src.u3.ip && 107 port == info->sig_port[dir]) { 108 /* GW->GK */ 109 110 /* Fix for Gnomemeeting */ 111 if (i > 0 && 112 get_h225_addr(ct, *data, &taddr[0], 113 &addr, &port) && 114 (ntohl(addr.ip) & 0xff000000) == 0x7f000000) 115 i = 0; 116 117 pr_debug("nf_nat_ras: set signal address %pI4:%hu->%pI4:%hu\n", 118 &addr.ip, port, 119 &ct->tuplehash[!dir].tuple.dst.u3.ip, 120 info->sig_port[!dir]); 121 return set_h225_addr(skb, protoff, data, 0, 122 &taddr[i], 123 &ct->tuplehash[!dir]. 124 tuple.dst.u3, 125 info->sig_port[!dir]); 126 } else if (addr.ip == ct->tuplehash[dir].tuple.dst.u3.ip && 127 port == info->sig_port[dir]) { 128 /* GK->GW */ 129 pr_debug("nf_nat_ras: set signal address %pI4:%hu->%pI4:%hu\n", 130 &addr.ip, port, 131 &ct->tuplehash[!dir].tuple.src.u3.ip, 132 info->sig_port[!dir]); 133 return set_h225_addr(skb, protoff, data, 0, 134 &taddr[i], 135 &ct->tuplehash[!dir]. 136 tuple.src.u3, 137 info->sig_port[!dir]); 138 } 139 } 140 } 141 142 return 0; 143} 144 145/****************************************************************************/ 146static int set_ras_addr(struct sk_buff *skb, struct nf_conn *ct, 147 enum ip_conntrack_info ctinfo, 148 unsigned int protoff, unsigned char **data, 149 TransportAddress *taddr, int count) 150{ 151 int dir = CTINFO2DIR(ctinfo); 152 int i; 153 __be16 port; 154 union nf_inet_addr addr; 155 156 for (i = 0; i < count; i++) { 157 if (get_h225_addr(ct, *data, &taddr[i], &addr, &port) && 158 addr.ip == ct->tuplehash[dir].tuple.src.u3.ip && 159 port == ct->tuplehash[dir].tuple.src.u.udp.port) { 160 pr_debug("nf_nat_ras: set rasAddress %pI4:%hu->%pI4:%hu\n", 161 &addr.ip, ntohs(port), 162 &ct->tuplehash[!dir].tuple.dst.u3.ip, 163 ntohs(ct->tuplehash[!dir].tuple.dst.u.udp.port)); 164 return set_h225_addr(skb, protoff, data, 0, &taddr[i], 165 &ct->tuplehash[!dir].tuple.dst.u3, 166 ct->tuplehash[!dir].tuple. 167 dst.u.udp.port); 168 } 169 } 170 171 return 0; 172} 173 174/****************************************************************************/ 175static int nat_rtp_rtcp(struct sk_buff *skb, struct nf_conn *ct, 176 enum ip_conntrack_info ctinfo, 177 unsigned int protoff, unsigned char **data, int dataoff, 178 H245_TransportAddress *taddr, 179 __be16 port, __be16 rtp_port, 180 struct nf_conntrack_expect *rtp_exp, 181 struct nf_conntrack_expect *rtcp_exp) 182{ 183 struct nf_ct_h323_master *info = nfct_help_data(ct); 184 int dir = CTINFO2DIR(ctinfo); 185 int i; 186 u_int16_t nated_port; 187 188 /* Set expectations for NAT */ 189 rtp_exp->saved_proto.udp.port = rtp_exp->tuple.dst.u.udp.port; 190 rtp_exp->expectfn = nf_nat_follow_master; 191 rtp_exp->dir = !dir; 192 rtcp_exp->saved_proto.udp.port = rtcp_exp->tuple.dst.u.udp.port; 193 rtcp_exp->expectfn = nf_nat_follow_master; 194 rtcp_exp->dir = !dir; 195 196 /* Lookup existing expects */ 197 for (i = 0; i < H323_RTP_CHANNEL_MAX; i++) { 198 if (info->rtp_port[i][dir] == rtp_port) { 199 /* Expected */ 200 201 /* Use allocated ports first. This will refresh 202 * the expects */ 203 rtp_exp->tuple.dst.u.udp.port = info->rtp_port[i][dir]; 204 rtcp_exp->tuple.dst.u.udp.port = 205 htons(ntohs(info->rtp_port[i][dir]) + 1); 206 break; 207 } else if (info->rtp_port[i][dir] == 0) { 208 /* Not expected */ 209 break; 210 } 211 } 212 213 /* Run out of expectations */ 214 if (i >= H323_RTP_CHANNEL_MAX) { 215 net_notice_ratelimited("nf_nat_h323: out of expectations\n"); 216 return 0; 217 } 218 219 /* Try to get a pair of ports. */ 220 for (nated_port = ntohs(rtp_exp->tuple.dst.u.udp.port); 221 nated_port != 0; nated_port += 2) { 222 int ret; 223 224 rtp_exp->tuple.dst.u.udp.port = htons(nated_port); 225 ret = nf_ct_expect_related(rtp_exp); 226 if (ret == 0) { 227 rtcp_exp->tuple.dst.u.udp.port = 228 htons(nated_port + 1); 229 ret = nf_ct_expect_related(rtcp_exp); 230 if (ret == 0) 231 break; 232 else if (ret == -EBUSY) { 233 nf_ct_unexpect_related(rtp_exp); 234 continue; 235 } else if (ret < 0) { 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) { /* No port available */ 247 net_notice_ratelimited("nf_nat_h323: out of RTP ports\n"); 248 return 0; 249 } 250 251 /* Modify signal */ 252 if (set_h245_addr(skb, protoff, data, dataoff, taddr, 253 &ct->tuplehash[!dir].tuple.dst.u3, 254 htons((port & htons(1)) ? nated_port + 1 : 255 nated_port)) == 0) { 256 /* Save ports */ 257 info->rtp_port[i][dir] = rtp_port; 258 info->rtp_port[i][!dir] = htons(nated_port); 259 } else { 260 nf_ct_unexpect_related(rtp_exp); 261 nf_ct_unexpect_related(rtcp_exp); 262 return -1; 263 } 264 265 /* Success */ 266 pr_debug("nf_nat_h323: expect RTP %pI4:%hu->%pI4:%hu\n", 267 &rtp_exp->tuple.src.u3.ip, 268 ntohs(rtp_exp->tuple.src.u.udp.port), 269 &rtp_exp->tuple.dst.u3.ip, 270 ntohs(rtp_exp->tuple.dst.u.udp.port)); 271 pr_debug("nf_nat_h323: expect RTCP %pI4:%hu->%pI4:%hu\n", 272 &rtcp_exp->tuple.src.u3.ip, 273 ntohs(rtcp_exp->tuple.src.u.udp.port), 274 &rtcp_exp->tuple.dst.u3.ip, 275 ntohs(rtcp_exp->tuple.dst.u.udp.port)); 276 277 return 0; 278} 279 280/****************************************************************************/ 281static int nat_t120(struct sk_buff *skb, struct nf_conn *ct, 282 enum ip_conntrack_info ctinfo, 283 unsigned int protoff, unsigned char **data, int dataoff, 284 H245_TransportAddress *taddr, __be16 port, 285 struct nf_conntrack_expect *exp) 286{ 287 int dir = CTINFO2DIR(ctinfo); 288 u_int16_t nated_port = ntohs(port); 289 290 /* Set expectations for NAT */ 291 exp->saved_proto.tcp.port = exp->tuple.dst.u.tcp.port; 292 exp->expectfn = nf_nat_follow_master; 293 exp->dir = !dir; 294 295 /* Try to get same port: if not, try to change it. */ 296 for (; nated_port != 0; nated_port++) { 297 int ret; 298 299 exp->tuple.dst.u.tcp.port = htons(nated_port); 300 ret = nf_ct_expect_related(exp); 301 if (ret == 0) 302 break; 303 else if (ret != -EBUSY) { 304 nated_port = 0; 305 break; 306 } 307 } 308 309 if (nated_port == 0) { /* No port available */ 310 net_notice_ratelimited("nf_nat_h323: out of TCP ports\n"); 311 return 0; 312 } 313 314 /* Modify signal */ 315 if (set_h245_addr(skb, protoff, data, dataoff, taddr, 316 &ct->tuplehash[!dir].tuple.dst.u3, 317 htons(nated_port)) < 0) { 318 nf_ct_unexpect_related(exp); 319 return -1; 320 } 321 322 pr_debug("nf_nat_h323: expect T.120 %pI4:%hu->%pI4:%hu\n", 323 &exp->tuple.src.u3.ip, 324 ntohs(exp->tuple.src.u.tcp.port), 325 &exp->tuple.dst.u3.ip, 326 ntohs(exp->tuple.dst.u.tcp.port)); 327 328 return 0; 329} 330 331/****************************************************************************/ 332static int nat_h245(struct sk_buff *skb, struct nf_conn *ct, 333 enum ip_conntrack_info ctinfo, 334 unsigned int protoff, unsigned char **data, int dataoff, 335 TransportAddress *taddr, __be16 port, 336 struct nf_conntrack_expect *exp) 337{ 338 struct nf_ct_h323_master *info = nfct_help_data(ct); 339 int dir = CTINFO2DIR(ctinfo); 340 u_int16_t nated_port = ntohs(port); 341 342 /* Set expectations for NAT */ 343 exp->saved_proto.tcp.port = exp->tuple.dst.u.tcp.port; 344 exp->expectfn = nf_nat_follow_master; 345 exp->dir = !dir; 346 347 /* Check existing expects */ 348 if (info->sig_port[dir] == port) 349 nated_port = ntohs(info->sig_port[!dir]); 350 351 /* Try to get same port: if not, try to change it. */ 352 for (; nated_port != 0; nated_port++) { 353 int ret; 354 355 exp->tuple.dst.u.tcp.port = htons(nated_port); 356 ret = nf_ct_expect_related(exp); 357 if (ret == 0) 358 break; 359 else if (ret != -EBUSY) { 360 nated_port = 0; 361 break; 362 } 363 } 364 365 if (nated_port == 0) { /* No port available */ 366 net_notice_ratelimited("nf_nat_q931: out of TCP ports\n"); 367 return 0; 368 } 369 370 /* Modify signal */ 371 if (set_h225_addr(skb, protoff, data, dataoff, taddr, 372 &ct->tuplehash[!dir].tuple.dst.u3, 373 htons(nated_port)) == 0) { 374 /* Save ports */ 375 info->sig_port[dir] = port; 376 info->sig_port[!dir] = htons(nated_port); 377 } else { 378 nf_ct_unexpect_related(exp); 379 return -1; 380 } 381 382 pr_debug("nf_nat_q931: expect H.245 %pI4:%hu->%pI4:%hu\n", 383 &exp->tuple.src.u3.ip, 384 ntohs(exp->tuple.src.u.tcp.port), 385 &exp->tuple.dst.u3.ip, 386 ntohs(exp->tuple.dst.u.tcp.port)); 387 388 return 0; 389} 390 391/**************************************************************************** 392 * This conntrack expect function replaces nf_conntrack_q931_expect() 393 * which was set by nf_conntrack_h323.c. 394 ****************************************************************************/ 395static void ip_nat_q931_expect(struct nf_conn *new, 396 struct nf_conntrack_expect *this) 397{ 398 struct nf_nat_range range; 399 400 if (this->tuple.src.u3.ip != 0) { /* Only accept calls from GK */ 401 nf_nat_follow_master(new, this); 402 return; 403 } 404 405 /* This must be a fresh one. */ 406 BUG_ON(new->status & IPS_NAT_DONE_MASK); 407 408 /* Change src to where master sends to */ 409 range.flags = NF_NAT_RANGE_MAP_IPS; 410 range.min_addr = range.max_addr = 411 new->tuplehash[!this->dir].tuple.src.u3; 412 nf_nat_setup_info(new, &range, NF_NAT_MANIP_SRC); 413 414 /* For DST manip, map port here to where it's expected. */ 415 range.flags = (NF_NAT_RANGE_MAP_IPS | NF_NAT_RANGE_PROTO_SPECIFIED); 416 range.min_proto = range.max_proto = this->saved_proto; 417 range.min_addr = range.max_addr = 418 new->master->tuplehash[!this->dir].tuple.src.u3; 419 nf_nat_setup_info(new, &range, NF_NAT_MANIP_DST); 420} 421 422/****************************************************************************/ 423static int nat_q931(struct sk_buff *skb, struct nf_conn *ct, 424 enum ip_conntrack_info ctinfo, 425 unsigned int protoff, unsigned char **data, 426 TransportAddress *taddr, int idx, 427 __be16 port, struct nf_conntrack_expect *exp) 428{ 429 struct nf_ct_h323_master *info = nfct_help_data(ct); 430 int dir = CTINFO2DIR(ctinfo); 431 u_int16_t nated_port = ntohs(port); 432 union nf_inet_addr addr; 433 434 /* Set expectations for NAT */ 435 exp->saved_proto.tcp.port = exp->tuple.dst.u.tcp.port; 436 exp->expectfn = ip_nat_q931_expect; 437 exp->dir = !dir; 438 439 /* Check existing expects */ 440 if (info->sig_port[dir] == port) 441 nated_port = ntohs(info->sig_port[!dir]); 442 443 /* Try to get same port: if not, try to change it. */ 444 for (; nated_port != 0; nated_port++) { 445 int ret; 446 447 exp->tuple.dst.u.tcp.port = htons(nated_port); 448 ret = nf_ct_expect_related(exp); 449 if (ret == 0) 450 break; 451 else if (ret != -EBUSY) { 452 nated_port = 0; 453 break; 454 } 455 } 456 457 if (nated_port == 0) { /* No port available */ 458 net_notice_ratelimited("nf_nat_ras: out of TCP ports\n"); 459 return 0; 460 } 461 462 /* Modify signal */ 463 if (set_h225_addr(skb, protoff, data, 0, &taddr[idx], 464 &ct->tuplehash[!dir].tuple.dst.u3, 465 htons(nated_port)) == 0) { 466 /* Save ports */ 467 info->sig_port[dir] = port; 468 info->sig_port[!dir] = htons(nated_port); 469 470 /* Fix for Gnomemeeting */ 471 if (idx > 0 && 472 get_h225_addr(ct, *data, &taddr[0], &addr, &port) && 473 (ntohl(addr.ip) & 0xff000000) == 0x7f000000) { 474 set_h225_addr(skb, protoff, data, 0, &taddr[0], 475 &ct->tuplehash[!dir].tuple.dst.u3, 476 info->sig_port[!dir]); 477 } 478 } else { 479 nf_ct_unexpect_related(exp); 480 return -1; 481 } 482 483 /* Success */ 484 pr_debug("nf_nat_ras: expect Q.931 %pI4:%hu->%pI4:%hu\n", 485 &exp->tuple.src.u3.ip, 486 ntohs(exp->tuple.src.u.tcp.port), 487 &exp->tuple.dst.u3.ip, 488 ntohs(exp->tuple.dst.u.tcp.port)); 489 490 return 0; 491} 492 493/****************************************************************************/ 494static void ip_nat_callforwarding_expect(struct nf_conn *new, 495 struct nf_conntrack_expect *this) 496{ 497 struct nf_nat_range range; 498 499 /* This must be a fresh one. */ 500 BUG_ON(new->status & IPS_NAT_DONE_MASK); 501 502 /* Change src to where master sends to */ 503 range.flags = NF_NAT_RANGE_MAP_IPS; 504 range.min_addr = range.max_addr = 505 new->tuplehash[!this->dir].tuple.src.u3; 506 nf_nat_setup_info(new, &range, NF_NAT_MANIP_SRC); 507 508 /* For DST manip, map port here to where it's expected. */ 509 range.flags = (NF_NAT_RANGE_MAP_IPS | NF_NAT_RANGE_PROTO_SPECIFIED); 510 range.min_proto = range.max_proto = this->saved_proto; 511 range.min_addr = range.max_addr = this->saved_addr; 512 nf_nat_setup_info(new, &range, NF_NAT_MANIP_DST); 513} 514 515/****************************************************************************/ 516static int nat_callforwarding(struct sk_buff *skb, struct nf_conn *ct, 517 enum ip_conntrack_info ctinfo, 518 unsigned int protoff, 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 /* Set expectations for NAT */ 527 exp->saved_addr = exp->tuple.dst.u3; 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 /* Try to get same port: if not, try to change it. */ 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) { /* No port available */ 548 net_notice_ratelimited("nf_nat_q931: out of TCP ports\n"); 549 return 0; 550 } 551 552 /* Modify signal */ 553 if (!set_h225_addr(skb, protoff, data, dataoff, taddr, 554 &ct->tuplehash[!dir].tuple.dst.u3, 555 htons(nated_port)) == 0) { 556 nf_ct_unexpect_related(exp); 557 return -1; 558 } 559 560 /* Success */ 561 pr_debug("nf_nat_q931: expect Call Forwarding %pI4:%hu->%pI4:%hu\n", 562 &exp->tuple.src.u3.ip, 563 ntohs(exp->tuple.src.u.tcp.port), 564 &exp->tuple.dst.u3.ip, 565 ntohs(exp->tuple.dst.u.tcp.port)); 566 567 return 0; 568} 569 570static struct nf_ct_helper_expectfn q931_nat = { 571 .name = "Q.931", 572 .expectfn = ip_nat_q931_expect, 573}; 574 575static struct nf_ct_helper_expectfn callforwarding_nat = { 576 .name = "callforwarding", 577 .expectfn = ip_nat_callforwarding_expect, 578}; 579 580/****************************************************************************/ 581static int __init init(void) 582{ 583 BUG_ON(set_h245_addr_hook != NULL); 584 BUG_ON(set_h225_addr_hook != NULL); 585 BUG_ON(set_sig_addr_hook != NULL); 586 BUG_ON(set_ras_addr_hook != NULL); 587 BUG_ON(nat_rtp_rtcp_hook != NULL); 588 BUG_ON(nat_t120_hook != NULL); 589 BUG_ON(nat_h245_hook != NULL); 590 BUG_ON(nat_callforwarding_hook != NULL); 591 BUG_ON(nat_q931_hook != NULL); 592 593 RCU_INIT_POINTER(set_h245_addr_hook, set_h245_addr); 594 RCU_INIT_POINTER(set_h225_addr_hook, set_h225_addr); 595 RCU_INIT_POINTER(set_sig_addr_hook, set_sig_addr); 596 RCU_INIT_POINTER(set_ras_addr_hook, set_ras_addr); 597 RCU_INIT_POINTER(nat_rtp_rtcp_hook, nat_rtp_rtcp); 598 RCU_INIT_POINTER(nat_t120_hook, nat_t120); 599 RCU_INIT_POINTER(nat_h245_hook, nat_h245); 600 RCU_INIT_POINTER(nat_callforwarding_hook, nat_callforwarding); 601 RCU_INIT_POINTER(nat_q931_hook, nat_q931); 602 nf_ct_helper_expectfn_register(&q931_nat); 603 nf_ct_helper_expectfn_register(&callforwarding_nat); 604 return 0; 605} 606 607/****************************************************************************/ 608static void __exit fini(void) 609{ 610 RCU_INIT_POINTER(set_h245_addr_hook, NULL); 611 RCU_INIT_POINTER(set_h225_addr_hook, NULL); 612 RCU_INIT_POINTER(set_sig_addr_hook, NULL); 613 RCU_INIT_POINTER(set_ras_addr_hook, NULL); 614 RCU_INIT_POINTER(nat_rtp_rtcp_hook, NULL); 615 RCU_INIT_POINTER(nat_t120_hook, NULL); 616 RCU_INIT_POINTER(nat_h245_hook, NULL); 617 RCU_INIT_POINTER(nat_callforwarding_hook, NULL); 618 RCU_INIT_POINTER(nat_q931_hook, NULL); 619 nf_ct_helper_expectfn_unregister(&q931_nat); 620 nf_ct_helper_expectfn_unregister(&callforwarding_nat); 621 synchronize_rcu(); 622} 623 624/****************************************************************************/ 625module_init(init); 626module_exit(fini); 627 628MODULE_AUTHOR("Jing Min Zhao <zhaojingmin@users.sourceforge.net>"); 629MODULE_DESCRIPTION("H.323 NAT helper"); 630MODULE_LICENSE("GPL"); 631MODULE_ALIAS("ip_nat_h323"); 632