Patrick McHardy | f587de0 | 2006-12-02 22:08:46 -0800 | [diff] [blame^] | 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 | |
| 47 | if ((*pskb)->nh.iph->protocol == IPPROTO_TCP) { |
| 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 */ |
| 58 | th = skb_header_pointer(*pskb, (*pskb)->nh.iph->ihl * 4, |
| 59 | sizeof(_tcph), &_tcph); |
| 60 | if (th == NULL) |
| 61 | return -1; |
| 62 | *data = (*pskb)->data + (*pskb)->nh.iph->ihl * 4 + |
| 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 */ |
| 76 | *data = (*pskb)->data + (*pskb)->nh.iph->ihl * 4 + |
| 77 | sizeof(struct udphdr); |
| 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 : |
| 259 | nated_port)) == 0) { |
| 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"); |