1 /*- 2 * alias_skinny.c 3 * 4 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 5 * 6 * Copyright (c) 2002, 2003 MarcusCom, Inc. 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 * 30 * Author: Joe Marcus Clarke <marcus@FreeBSD.org> 31 * 32 * $FreeBSD$ 33 */ 34 35 #ifdef _KERNEL 36 #include <sys/param.h> 37 #include <sys/kernel.h> 38 #include <sys/module.h> 39 #else 40 #include <errno.h> 41 #include <stdio.h> 42 #include <unistd.h> 43 #endif 44 45 #include <netinet/in_systm.h> 46 #include <netinet/in.h> 47 #include <netinet/ip.h> 48 #include <netinet/tcp.h> 49 50 #ifdef _KERNEL 51 #include <netinet/libalias/alias_local.h> 52 #include <netinet/libalias/alias_mod.h> 53 #else 54 #include "alias_local.h" 55 #include "alias_mod.h" 56 #endif 57 58 static void 59 AliasHandleSkinny(struct libalias *, struct ip *, struct alias_link *); 60 61 static int 62 fingerprint(struct libalias *la, struct alias_data *ah) 63 { 64 if (ah->dport == NULL || ah->sport == NULL || ah->lnk == NULL) 65 return (-1); 66 if (la->skinnyPort != 0 && (ntohs(*ah->sport) == la->skinnyPort || 67 ntohs(*ah->dport) == la->skinnyPort)) 68 return (0); 69 return (-1); 70 } 71 72 static int 73 protohandler(struct libalias *la, struct ip *pip, struct alias_data *ah) 74 { 75 AliasHandleSkinny(la, pip, ah->lnk); 76 return (0); 77 } 78 79 struct proto_handler handlers[] = { 80 { 81 .pri = 110, 82 .dir = IN|OUT, 83 .proto = TCP, 84 .fingerprint = &fingerprint, 85 .protohandler = &protohandler 86 }, 87 { EOH } 88 }; 89 90 static int 91 mod_handler(module_t mod, int type, void *data) 92 { 93 int error; 94 95 switch (type) { 96 case MOD_LOAD: 97 error = 0; 98 LibAliasAttachHandlers(handlers); 99 break; 100 case MOD_UNLOAD: 101 error = 0; 102 LibAliasDetachHandlers(handlers); 103 break; 104 default: 105 error = EINVAL; 106 } 107 return (error); 108 } 109 110 #ifdef _KERNEL 111 static 112 #endif 113 moduledata_t alias_mod = { 114 "alias_skinny", mod_handler, NULL 115 }; 116 117 #ifdef _KERNEL 118 DECLARE_MODULE(alias_skinny, alias_mod, SI_SUB_DRIVERS, SI_ORDER_SECOND); 119 MODULE_VERSION(alias_skinny, 1); 120 MODULE_DEPEND(alias_skinny, libalias, 1, 1, 1); 121 #endif 122 123 /* 124 * alias_skinny.c handles the translation for the Cisco Skinny Station 125 * protocol. Skinny typically uses TCP port 2000 to set up calls between 126 * a Cisco Call Manager and a Cisco IP phone. When a phone comes on line, 127 * it first needs to register with the Call Manager. To do this it sends 128 * a registration message. This message contains the IP address of the 129 * IP phone. This message must then be translated to reflect our global 130 * IP address. Along with the registration message (and usually in the 131 * same packet), the phone sends an IP port message. This message indicates 132 * the TCP port over which it will communicate. 133 * 134 * When a call is placed from the phone, the Call Manager will send an 135 * Open Receive Channel message to the phone to let the caller know someone 136 * has answered. The phone then sends back an Open Receive Channel 137 * Acknowledgement. In this packet, the phone sends its IP address again, 138 * and the UDP port over which the voice traffic should flow. These values 139 * need translation. Right after the Open Receive Channel Acknowledgement, 140 * the Call Manager sends a Start Media Transmission message indicating the 141 * call is connected. This message contains the IP address and UDP port 142 * number of the remote (called) party. Once this message is translated, the 143 * call can commence. The called part sends the first UDP packet to the 144 * calling phone at the pre-arranged UDP port in the Open Receive Channel 145 * Acknowledgement. 146 * 147 * Skinny is a Cisco-proprietary protocol and is a trademark of Cisco Systems, 148 * Inc. All rights reserved. 149 */ 150 151 /* #define LIBALIAS_DEBUG 1 */ 152 153 /* Message types that need translating */ 154 #define REG_MSG 0x00000001 155 #define IP_PORT_MSG 0x00000002 156 #define OPNRCVCH_ACK 0x00000022 157 #define START_MEDIATX 0x0000008a 158 159 struct skinny_header { 160 u_int32_t len; 161 u_int32_t reserved; 162 u_int32_t msgId; 163 }; 164 165 struct RegisterMessage { 166 u_int32_t msgId; 167 char devName [16]; 168 u_int32_t uid; 169 u_int32_t instance; 170 u_int32_t ipAddr; 171 u_char devType; 172 u_int32_t maxStreams; 173 }; 174 175 struct IpPortMessage { 176 u_int32_t msgId; 177 u_int32_t stationIpPort; /* Note: Skinny uses 32-bit port 178 * numbers */ 179 }; 180 181 struct OpenReceiveChannelAck { 182 u_int32_t msgId; 183 u_int32_t status; 184 u_int32_t ipAddr; 185 u_int32_t port; 186 u_int32_t passThruPartyID; 187 }; 188 189 struct StartMediaTransmission { 190 u_int32_t msgId; 191 u_int32_t conferenceID; 192 u_int32_t passThruPartyID; 193 u_int32_t remoteIpAddr; 194 u_int32_t remotePort; 195 u_int32_t MSPacket; 196 u_int32_t payloadCap; 197 u_int32_t precedence; 198 u_int32_t silenceSuppression; 199 u_short maxFramesPerPacket; 200 u_int32_t G723BitRate; 201 }; 202 203 typedef enum { 204 ClientToServer = 0, 205 ServerToClient = 1 206 } ConvDirection; 207 208 static int 209 alias_skinny_reg_msg(struct RegisterMessage *reg_msg, struct ip *pip, 210 struct tcphdr *tc, struct alias_link *lnk, 211 ConvDirection direction) 212 { 213 (void)direction; 214 215 reg_msg->ipAddr = (u_int32_t)GetAliasAddress(lnk).s_addr; 216 217 tc->th_sum = 0; 218 #ifdef _KERNEL 219 tc->th_x2 = 1; 220 #else 221 tc->th_sum = TcpChecksum(pip); 222 #endif 223 224 return (0); 225 } 226 227 static int 228 alias_skinny_startmedia(struct StartMediaTransmission *start_media, 229 struct ip *pip, struct tcphdr *tc, 230 struct alias_link *lnk, u_int32_t localIpAddr, 231 ConvDirection direction) 232 { 233 struct in_addr dst, src; 234 235 (void)pip; 236 (void)tc; 237 (void)lnk; 238 (void)direction; 239 240 dst.s_addr = start_media->remoteIpAddr; 241 src.s_addr = localIpAddr; 242 243 /* 244 * XXX I should probably handle in bound global translations as 245 * well. 246 */ 247 248 return (0); 249 } 250 251 static int 252 alias_skinny_port_msg(struct IpPortMessage *port_msg, struct ip *pip, 253 struct tcphdr *tc, struct alias_link *lnk, 254 ConvDirection direction) 255 { 256 (void)direction; 257 258 port_msg->stationIpPort = (u_int32_t)ntohs(GetAliasPort(lnk)); 259 260 tc->th_sum = 0; 261 #ifdef _KERNEL 262 tc->th_x2 = 1; 263 #else 264 tc->th_sum = TcpChecksum(pip); 265 #endif 266 return (0); 267 } 268 269 static int 270 alias_skinny_opnrcvch_ack(struct libalias *la, struct OpenReceiveChannelAck *opnrcvch_ack, 271 struct ip *pip, struct tcphdr *tc, 272 struct alias_link *lnk, u_int32_t * localIpAddr, 273 ConvDirection direction) 274 { 275 struct in_addr null_addr; 276 struct alias_link *opnrcv_lnk; 277 u_int32_t localPort; 278 279 (void)lnk; 280 (void)direction; 281 282 *localIpAddr = (u_int32_t)opnrcvch_ack->ipAddr; 283 localPort = opnrcvch_ack->port; 284 285 null_addr.s_addr = INADDR_ANY; 286 opnrcv_lnk = FindUdpTcpOut(la, pip->ip_src, null_addr, 287 htons((u_short) opnrcvch_ack->port), 0, 288 IPPROTO_UDP, 1); 289 opnrcvch_ack->ipAddr = (u_int32_t)GetAliasAddress(opnrcv_lnk).s_addr; 290 opnrcvch_ack->port = (u_int32_t)ntohs(GetAliasPort(opnrcv_lnk)); 291 292 tc->th_sum = 0; 293 #ifdef _KERNEL 294 tc->th_x2 = 1; 295 #else 296 tc->th_sum = TcpChecksum(pip); 297 #endif 298 return (0); 299 } 300 301 static void 302 AliasHandleSkinny(struct libalias *la, struct ip *pip, struct alias_link *lnk) 303 { 304 size_t hlen, tlen, dlen; 305 struct tcphdr *tc; 306 u_int32_t msgId, t, len, lip; 307 struct skinny_header *sd; 308 size_t orig_len, skinny_hdr_len = sizeof(struct skinny_header); 309 ConvDirection direction; 310 311 lip = -1; 312 tc = (struct tcphdr *)ip_next(pip); 313 hlen = (pip->ip_hl + tc->th_off) << 2; 314 tlen = ntohs(pip->ip_len); 315 dlen = tlen - hlen; 316 317 sd = (struct skinny_header *)tcp_next(tc); 318 319 /* 320 * XXX This direction is reserved for future use. I still need to 321 * handle the scenario where the call manager is on the inside, and 322 * the calling phone is on the global outside. 323 */ 324 if (ntohs(tc->th_dport) == la->skinnyPort) 325 direction = ClientToServer; 326 else if (ntohs(tc->th_sport) == la->skinnyPort) 327 direction = ServerToClient; 328 else { 329 #ifdef LIBALIAS_DEBUG 330 fprintf(stderr, 331 "PacketAlias/Skinny: Invalid port number, not a Skinny packet\n"); 332 #endif 333 return; 334 } 335 336 orig_len = dlen; 337 /* 338 * Skinny packets can contain many messages. We need to loop 339 * through the packet using len to determine message boundaries. 340 * This comes into play big time with port messages being in the 341 * same packet as register messages. Also, open receive channel 342 * acks are usually buried in a packet some 400 bytes long. 343 */ 344 while (dlen >= skinny_hdr_len) { 345 len = (sd->len); 346 msgId = (sd->msgId); 347 t = len; 348 349 if (t > orig_len || t > dlen) { 350 #ifdef LIBALIAS_DEBUG 351 fprintf(stderr, 352 "PacketAlias/Skinny: Not a skinny packet, invalid length \n"); 353 #endif 354 return; 355 } 356 switch (msgId) { 357 case REG_MSG: { 358 struct RegisterMessage *reg_mesg; 359 360 if (len < (int)sizeof(struct RegisterMessage)) { 361 #ifdef LIBALIAS_DEBUG 362 fprintf(stderr, 363 "PacketAlias/Skinny: Not a skinny packet, bad registration message\n"); 364 #endif 365 return; 366 } 367 reg_mesg = (struct RegisterMessage *)&sd->msgId; 368 #ifdef LIBALIAS_DEBUG 369 fprintf(stderr, 370 "PacketAlias/Skinny: Received a register message"); 371 #endif 372 alias_skinny_reg_msg(reg_mesg, pip, tc, lnk, direction); 373 break; 374 } 375 case IP_PORT_MSG: { 376 struct IpPortMessage *port_mesg; 377 378 if (len < (int)sizeof(struct IpPortMessage)) { 379 #ifdef LIBALIAS_DEBUG 380 fprintf(stderr, 381 "PacketAlias/Skinny: Not a skinny packet, port message\n"); 382 #endif 383 return; 384 } 385 #ifdef LIBALIAS_DEBUG 386 fprintf(stderr, 387 "PacketAlias/Skinny: Received ipport message\n"); 388 #endif 389 port_mesg = (struct IpPortMessage *)&sd->msgId; 390 alias_skinny_port_msg(port_mesg, pip, tc, lnk, direction); 391 break; 392 } 393 case OPNRCVCH_ACK: { 394 struct OpenReceiveChannelAck *opnrcvchn_ack; 395 396 if (len < (int)sizeof(struct OpenReceiveChannelAck)) { 397 #ifdef LIBALIAS_DEBUG 398 fprintf(stderr, 399 "PacketAlias/Skinny: Not a skinny packet, packet,OpnRcvChnAckMsg\n"); 400 #endif 401 return; 402 } 403 #ifdef LIBALIAS_DEBUG 404 fprintf(stderr, 405 "PacketAlias/Skinny: Received open rcv channel msg\n"); 406 #endif 407 opnrcvchn_ack = (struct OpenReceiveChannelAck *)&sd->msgId; 408 alias_skinny_opnrcvch_ack(la, opnrcvchn_ack, pip, tc, lnk, &lip, direction); 409 break; 410 } 411 case START_MEDIATX: { 412 struct StartMediaTransmission *startmedia_tx; 413 414 if (len < (int)sizeof(struct StartMediaTransmission)) { 415 #ifdef LIBALIAS_DEBUG 416 fprintf(stderr, 417 "PacketAlias/Skinny: Not a skinny packet,StartMediaTx Message\n"); 418 #endif 419 return; 420 } 421 if (lip == -1) { 422 #ifdef LIBALIAS_DEBUG 423 fprintf(stderr, 424 "PacketAlias/Skinny: received a" 425 " packet,StartMediaTx Message before" 426 " packet,OpnRcvChnAckMsg\n" 427 #endif 428 return; 429 } 430 431 #ifdef LIBALIAS_DEBUG 432 fprintf(stderr, 433 "PacketAlias/Skinny: Received start media trans msg\n"); 434 #endif 435 startmedia_tx = (struct StartMediaTransmission *)&sd->msgId; 436 alias_skinny_startmedia(startmedia_tx, pip, tc, lnk, lip, direction); 437 break; 438 } 439 default: 440 break; 441 } 442 /* Place the pointer at the next message in the packet. */ 443 dlen -= len + (skinny_hdr_len - sizeof(msgId)); 444 sd = (struct skinny_header *)(((char *)&sd->msgId) + len); 445 } 446 } 447