4 * Copyright (c) 2002, 2003 MarcusCom, Inc.
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * Author: Joe Marcus Clarke <marcus@FreeBSD.org>
35 #include <sys/types.h>
36 #include <sys/socket.h>
37 #include <netinet/in_systm.h>
38 #include <netinet/in.h>
39 #include <arpa/inet.h>
40 #include <netinet/ip.h>
41 #include <netinet/tcp.h>
42 #include <netinet/udp.h>
45 #include "alias_local.h"
48 * alias_skinny.c handles the translation for the Cisco Skinny Station
49 * protocol. Skinny typically uses TCP port 2000 to set up calls between
50 * a Cisco Call Manager and a Cisco IP phone. When a phone comes on line,
51 * it first needs to register with the Call Manager. To do this it sends
52 * a registration message. This message contains the IP address of the
53 * IP phone. This message must then be translated to reflect our global
54 * IP address. Along with the registration message (and usually in the
55 * same packet), the phone sends an IP port message. This message indicates
56 * the TCP port over which it will communicate.
58 * When a call is placed from the phone, the Call Manager will send an
59 * Open Receive Channel message to the phone to let the caller know someone
60 * has answered. The phone then sends back an Open Receive Channel
61 * Acknowledgement. In this packet, the phone sends its IP address again,
62 * and the UDP port over which the voice traffic should flow. These values
63 * need translation. Right after the Open Receive Channel Acknowledgement,
64 * the Call Manager sends a Start Media Transmission message indicating the
65 * call is connected. This message contains the IP address and UDP port
66 * number of the remote (called) party. Once this message is translated, the
67 * call can commence. The called part sends the first UDP packet to the
68 * calling phone at the pre-arranged UDP port in the Open Receive Channel
71 * Skinny is a Cisco-proprietary protocol and is a trademark of Cisco Systems,
72 * Inc. All rights reserved.
77 /* Message types that need translating */
78 #define REG_MSG 0x00000001
79 #define IP_PORT_MSG 0x00000002
80 #define OPNRCVCH_ACK 0x00000022
81 #define START_MEDIATX 0x0000008a
83 struct skinny_header {
89 struct RegisterMessage {
99 struct IpPortMessage {
101 u_int32_t stationIpPort; /* Note: Skinny uses 32-bit port
105 struct OpenReceiveChannelAck {
110 u_int32_t passThruPartyID;
113 struct StartMediaTransmission {
115 u_int32_t conferenceID;
116 u_int32_t passThruPartyID;
117 u_int32_t remoteIpAddr;
118 u_int32_t remotePort;
120 u_int32_t payloadCap;
121 u_int32_t precedence;
122 u_int32_t silenceSuppression;
123 u_short maxFramesPerPacket;
124 u_int32_t G723BitRate;
134 alias_skinny_reg_msg(struct RegisterMessage *reg_msg, struct ip *pip,
135 struct tcphdr *tc, struct alias_link *lnk,
136 ConvDirection direction)
140 reg_msg->ipAddr = (u_int32_t) GetAliasAddress(lnk).s_addr;
143 tc->th_sum = TcpChecksum(pip);
149 alias_skinny_startmedia(struct StartMediaTransmission *start_media,
150 struct ip *pip, struct tcphdr *tc,
151 struct alias_link *lnk, u_int32_t localIpAddr,
152 ConvDirection direction)
154 struct in_addr dst, src;
161 dst.s_addr = start_media->remoteIpAddr;
162 src.s_addr = localIpAddr;
165 * XXX I should probably handle in bound global translations as
173 alias_skinny_port_msg(struct IpPortMessage *port_msg, struct ip *pip,
174 struct tcphdr *tc, struct alias_link *lnk,
175 ConvDirection direction)
179 port_msg->stationIpPort = (u_int32_t) ntohs(GetAliasPort(lnk));
182 tc->th_sum = TcpChecksum(pip);
188 alias_skinny_opnrcvch_ack(struct libalias *la, struct OpenReceiveChannelAck *opnrcvch_ack,
189 struct ip *pip, struct tcphdr *tc,
190 struct alias_link *lnk, u_int32_t * localIpAddr,
191 ConvDirection direction)
193 struct in_addr null_addr;
194 struct alias_link *opnrcv_lnk;
200 *localIpAddr = (u_int32_t) opnrcvch_ack->ipAddr;
201 localPort = opnrcvch_ack->port;
203 null_addr.s_addr = INADDR_ANY;
204 opnrcv_lnk = FindUdpTcpOut(la, pip->ip_src, null_addr,
205 htons((u_short) opnrcvch_ack->port), 0,
207 opnrcvch_ack->ipAddr = (u_int32_t) GetAliasAddress(opnrcv_lnk).s_addr;
208 opnrcvch_ack->port = (u_int32_t) ntohs(GetAliasPort(opnrcv_lnk));
211 tc->th_sum = TcpChecksum(pip);
217 AliasHandleSkinny(struct libalias *la, struct ip *pip, struct alias_link *lnk)
219 int hlen, tlen, dlen;
221 int32_t msgId, len, t, lip;
222 struct skinny_header *sd;
223 int orig_len, skinny_hdr_len = sizeof(struct skinny_header);
224 ConvDirection direction;
226 tc = (struct tcphdr *)ip_next(pip);
227 hlen = (pip->ip_hl + tc->th_off) << 2;
228 tlen = ntohs(pip->ip_len);
231 sd = (struct skinny_header *)tcp_next(tc);
234 * XXX This direction is reserved for future use. I still need to
235 * handle the scenario where the call manager is on the inside, and
236 * the calling phone is on the global outside.
238 if (ntohs(tc->th_dport) == la->skinnyPort) {
239 direction = ClientToServer;
240 } else if (ntohs(tc->th_sport) == la->skinnyPort) {
241 direction = ServerToClient;
245 "PacketAlias/Skinny: Invalid port number, not a Skinny packet\n");
252 * Skinny packets can contain many messages. We need to loop
253 * through the packet using len to determine message boundaries.
254 * This comes into play big time with port messages being in the
255 * same packet as register messages. Also, open receive channel
256 * acks are usually buried in a pakcet some 400 bytes long.
258 while (dlen >= skinny_hdr_len) {
263 if (t > orig_len || t > dlen) {
266 "PacketAlias/Skinny: Not a skinny packet, invalid length \n");
272 struct RegisterMessage *reg_mesg;
274 if (len < (int)sizeof(struct RegisterMessage)) {
277 "PacketAlias/Skinny: Not a skinny packet, bad registration message\n");
281 reg_mesg = (struct RegisterMessage *)&sd->msgId;
284 "PacketAlias/Skinny: Received a register message");
286 alias_skinny_reg_msg(reg_mesg, pip, tc, lnk, direction);
290 struct IpPortMessage *port_mesg;
292 if (len < (int)sizeof(struct IpPortMessage)) {
295 "PacketAlias/Skinny: Not a skinny packet, port message\n");
301 "PacketAlias/Skinny: Received ipport message\n");
303 port_mesg = (struct IpPortMessage *)&sd->msgId;
304 alias_skinny_port_msg(port_mesg, pip, tc, lnk, direction);
308 struct OpenReceiveChannelAck *opnrcvchn_ack;
310 if (len < (int)sizeof(struct OpenReceiveChannelAck)) {
313 "PacketAlias/Skinny: Not a skinny packet, packet,OpnRcvChnAckMsg\n");
319 "PacketAlias/Skinny: Received open rcv channel msg\n");
321 opnrcvchn_ack = (struct OpenReceiveChannelAck *)&sd->msgId;
322 alias_skinny_opnrcvch_ack(la, opnrcvchn_ack, pip, tc, lnk, &lip, direction);
325 case START_MEDIATX: {
326 struct StartMediaTransmission *startmedia_tx;
328 if (len < (int)sizeof(struct StartMediaTransmission)) {
331 "PacketAlias/Skinny: Not a skinny packet,StartMediaTx Message\n");
337 "PacketAlias/Skinny: Received start media trans msg\n");
339 startmedia_tx = (struct StartMediaTransmission *)&sd->msgId;
340 alias_skinny_startmedia(startmedia_tx, pip, tc, lnk, lip, direction);
346 /* Place the pointer at the next message in the packet. */
347 dlen -= len + (skinny_hdr_len - sizeof(msgId));
348 sd = (struct skinny_header *)(((char *)&sd->msgId) + len);