448 lines
12 KiB
C
448 lines
12 KiB
C
/*-
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* alias_skinny.c
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*
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* Copyright (c) 2002, 2003 MarcusCom, Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* Author: Joe Marcus Clarke <marcus@FreeBSD.org>
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*
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* $FreeBSD$
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*/
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#ifdef _KERNEL
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/module.h>
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#else
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#include <errno.h>
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#include <stdio.h>
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#include <unistd.h>
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#endif
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#include <netinet/in_systm.h>
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#include <netinet/in.h>
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#include <netinet/ip.h>
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#include <netinet/tcp.h>
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#ifdef _KERNEL
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#include <netinet/libalias/alias_local.h>
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#include <netinet/libalias/alias_mod.h>
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#else
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#include "alias_local.h"
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#include "alias_mod.h"
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#endif
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static void
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AliasHandleSkinny(struct libalias *, struct ip *, struct alias_link *);
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static int
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fingerprint(struct libalias *la, struct alias_data *ah)
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{
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if (ah->dport == NULL || ah->sport == NULL || ah->lnk == NULL)
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return (-1);
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if (la->skinnyPort != 0 && (ntohs(*ah->sport) == la->skinnyPort ||
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ntohs(*ah->dport) == la->skinnyPort))
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return (0);
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return (-1);
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}
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static int
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protohandler(struct libalias *la, struct ip *pip, struct alias_data *ah)
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{
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AliasHandleSkinny(la, pip, ah->lnk);
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return (0);
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}
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struct proto_handler handlers[] = {
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{
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.pri = 110,
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.dir = IN|OUT,
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.proto = TCP,
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.fingerprint = &fingerprint,
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.protohandler = &protohandler
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},
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{ EOH }
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};
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static int
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mod_handler(module_t mod, int type, void *data)
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{
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int error;
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switch (type) {
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case MOD_LOAD:
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error = 0;
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LibAliasAttachHandlers(handlers);
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break;
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case MOD_UNLOAD:
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error = 0;
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LibAliasDetachHandlers(handlers);
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break;
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default:
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error = EINVAL;
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}
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return (error);
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}
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#ifdef _KERNEL
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static
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#endif
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moduledata_t alias_mod = {
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"alias_skinny", mod_handler, NULL
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};
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#ifdef _KERNEL
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DECLARE_MODULE(alias_skinny, alias_mod, SI_SUB_DRIVERS, SI_ORDER_SECOND);
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MODULE_VERSION(alias_skinny, 1);
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MODULE_DEPEND(alias_skinny, libalias, 1, 1, 1);
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#endif
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/*
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* alias_skinny.c handles the translation for the Cisco Skinny Station
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* protocol. Skinny typically uses TCP port 2000 to set up calls between
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* a Cisco Call Manager and a Cisco IP phone. When a phone comes on line,
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* it first needs to register with the Call Manager. To do this it sends
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* a registration message. This message contains the IP address of the
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* IP phone. This message must then be translated to reflect our global
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* IP address. Along with the registration message (and usually in the
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* same packet), the phone sends an IP port message. This message indicates
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* the TCP port over which it will communicate.
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*
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* When a call is placed from the phone, the Call Manager will send an
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* Open Receive Channel message to the phone to let the caller know someone
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* has answered. The phone then sends back an Open Receive Channel
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* Acknowledgement. In this packet, the phone sends its IP address again,
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* and the UDP port over which the voice traffic should flow. These values
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* need translation. Right after the Open Receive Channel Acknowledgement,
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* the Call Manager sends a Start Media Transmission message indicating the
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* call is connected. This message contains the IP address and UDP port
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* number of the remote (called) party. Once this message is translated, the
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* call can commence. The called part sends the first UDP packet to the
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* calling phone at the pre-arranged UDP port in the Open Receive Channel
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* Acknowledgement.
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*
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* Skinny is a Cisco-proprietary protocol and is a trademark of Cisco Systems,
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* Inc. All rights reserved.
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*/
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/* #define LIBALIAS_DEBUG 1 */
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/* Message types that need translating */
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#define REG_MSG 0x00000001
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#define IP_PORT_MSG 0x00000002
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#define OPNRCVCH_ACK 0x00000022
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#define START_MEDIATX 0x0000008a
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struct skinny_header {
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u_int32_t len;
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u_int32_t reserved;
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u_int32_t msgId;
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};
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struct RegisterMessage {
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u_int32_t msgId;
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char devName [16];
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u_int32_t uid;
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u_int32_t instance;
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u_int32_t ipAddr;
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u_char devType;
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u_int32_t maxStreams;
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};
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struct IpPortMessage {
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u_int32_t msgId;
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u_int32_t stationIpPort; /* Note: Skinny uses 32-bit port
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* numbers */
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};
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struct OpenReceiveChannelAck {
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u_int32_t msgId;
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u_int32_t status;
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u_int32_t ipAddr;
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u_int32_t port;
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u_int32_t passThruPartyID;
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};
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struct StartMediaTransmission {
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u_int32_t msgId;
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u_int32_t conferenceID;
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u_int32_t passThruPartyID;
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u_int32_t remoteIpAddr;
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u_int32_t remotePort;
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u_int32_t MSPacket;
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u_int32_t payloadCap;
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u_int32_t precedence;
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u_int32_t silenceSuppression;
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u_short maxFramesPerPacket;
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u_int32_t G723BitRate;
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};
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typedef enum {
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ClientToServer = 0,
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ServerToClient = 1
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} ConvDirection;
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static int
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alias_skinny_reg_msg(struct RegisterMessage *reg_msg, struct ip *pip,
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struct tcphdr *tc, struct alias_link *lnk,
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ConvDirection direction)
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{
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(void)direction;
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reg_msg->ipAddr = (u_int32_t) GetAliasAddress(lnk).s_addr;
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tc->th_sum = 0;
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#ifdef _KERNEL
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tc->th_x2 = 1;
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#else
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tc->th_sum = TcpChecksum(pip);
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#endif
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return (0);
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}
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static int
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alias_skinny_startmedia(struct StartMediaTransmission *start_media,
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struct ip *pip, struct tcphdr *tc,
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struct alias_link *lnk, u_int32_t localIpAddr,
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ConvDirection direction)
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{
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struct in_addr dst, src;
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(void)pip;
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(void)tc;
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(void)lnk;
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(void)direction;
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dst.s_addr = start_media->remoteIpAddr;
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src.s_addr = localIpAddr;
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/*
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* XXX I should probably handle in bound global translations as
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* well.
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*/
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return (0);
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}
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static int
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alias_skinny_port_msg(struct IpPortMessage *port_msg, struct ip *pip,
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struct tcphdr *tc, struct alias_link *lnk,
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ConvDirection direction)
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{
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(void)direction;
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port_msg->stationIpPort = (u_int32_t) ntohs(GetAliasPort(lnk));
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tc->th_sum = 0;
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#ifdef _KERNEL
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tc->th_x2 = 1;
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#else
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tc->th_sum = TcpChecksum(pip);
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#endif
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return (0);
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}
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static int
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alias_skinny_opnrcvch_ack(struct libalias *la, struct OpenReceiveChannelAck *opnrcvch_ack,
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struct ip *pip, struct tcphdr *tc,
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struct alias_link *lnk, u_int32_t * localIpAddr,
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ConvDirection direction)
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{
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struct in_addr null_addr;
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struct alias_link *opnrcv_lnk;
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u_int32_t localPort;
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(void)lnk;
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(void)direction;
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*localIpAddr = (u_int32_t) opnrcvch_ack->ipAddr;
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localPort = opnrcvch_ack->port;
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null_addr.s_addr = INADDR_ANY;
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opnrcv_lnk = FindUdpTcpOut(la, pip->ip_src, null_addr,
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htons((u_short) opnrcvch_ack->port), 0,
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IPPROTO_UDP, 1);
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opnrcvch_ack->ipAddr = (u_int32_t) GetAliasAddress(opnrcv_lnk).s_addr;
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opnrcvch_ack->port = (u_int32_t) ntohs(GetAliasPort(opnrcv_lnk));
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tc->th_sum = 0;
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#ifdef _KERNEL
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tc->th_x2 = 1;
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#else
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tc->th_sum = TcpChecksum(pip);
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#endif
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return (0);
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}
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static void
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AliasHandleSkinny(struct libalias *la, struct ip *pip, struct alias_link *lnk)
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{
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size_t hlen, tlen, dlen;
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struct tcphdr *tc;
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u_int32_t msgId, t, len, lip;
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struct skinny_header *sd;
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size_t orig_len, skinny_hdr_len = sizeof(struct skinny_header);
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ConvDirection direction;
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lip = -1;
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tc = (struct tcphdr *)ip_next(pip);
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hlen = (pip->ip_hl + tc->th_off) << 2;
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tlen = ntohs(pip->ip_len);
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dlen = tlen - hlen;
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sd = (struct skinny_header *)tcp_next(tc);
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/*
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* XXX This direction is reserved for future use. I still need to
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* handle the scenario where the call manager is on the inside, and
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* the calling phone is on the global outside.
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*/
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if (ntohs(tc->th_dport) == la->skinnyPort) {
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direction = ClientToServer;
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} else if (ntohs(tc->th_sport) == la->skinnyPort) {
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direction = ServerToClient;
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} else {
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#ifdef LIBALIAS_DEBUG
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fprintf(stderr,
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"PacketAlias/Skinny: Invalid port number, not a Skinny packet\n");
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#endif
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return;
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}
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orig_len = dlen;
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/*
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* Skinny packets can contain many messages. We need to loop
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* through the packet using len to determine message boundaries.
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* This comes into play big time with port messages being in the
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* same packet as register messages. Also, open receive channel
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* acks are usually buried in a packet some 400 bytes long.
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*/
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while (dlen >= skinny_hdr_len) {
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len = (sd->len);
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msgId = (sd->msgId);
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t = len;
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if (t > orig_len || t > dlen) {
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#ifdef LIBALIAS_DEBUG
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fprintf(stderr,
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"PacketAlias/Skinny: Not a skinny packet, invalid length \n");
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#endif
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return;
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}
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switch (msgId) {
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case REG_MSG: {
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struct RegisterMessage *reg_mesg;
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if (len < (int)sizeof(struct RegisterMessage)) {
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#ifdef LIBALIAS_DEBUG
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fprintf(stderr,
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"PacketAlias/Skinny: Not a skinny packet, bad registration message\n");
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#endif
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return;
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}
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reg_mesg = (struct RegisterMessage *)&sd->msgId;
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#ifdef LIBALIAS_DEBUG
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fprintf(stderr,
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"PacketAlias/Skinny: Received a register message");
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#endif
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alias_skinny_reg_msg(reg_mesg, pip, tc, lnk, direction);
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break;
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}
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case IP_PORT_MSG: {
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struct IpPortMessage *port_mesg;
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if (len < (int)sizeof(struct IpPortMessage)) {
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#ifdef LIBALIAS_DEBUG
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fprintf(stderr,
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"PacketAlias/Skinny: Not a skinny packet, port message\n");
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#endif
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return;
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}
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#ifdef LIBALIAS_DEBUG
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fprintf(stderr,
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"PacketAlias/Skinny: Received ipport message\n");
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#endif
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port_mesg = (struct IpPortMessage *)&sd->msgId;
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alias_skinny_port_msg(port_mesg, pip, tc, lnk, direction);
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break;
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}
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case OPNRCVCH_ACK: {
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struct OpenReceiveChannelAck *opnrcvchn_ack;
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if (len < (int)sizeof(struct OpenReceiveChannelAck)) {
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#ifdef LIBALIAS_DEBUG
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fprintf(stderr,
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"PacketAlias/Skinny: Not a skinny packet, packet,OpnRcvChnAckMsg\n");
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#endif
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return;
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}
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#ifdef LIBALIAS_DEBUG
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fprintf(stderr,
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"PacketAlias/Skinny: Received open rcv channel msg\n");
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#endif
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opnrcvchn_ack = (struct OpenReceiveChannelAck *)&sd->msgId;
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alias_skinny_opnrcvch_ack(la, opnrcvchn_ack, pip, tc, lnk, &lip, direction);
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break;
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}
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case START_MEDIATX: {
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struct StartMediaTransmission *startmedia_tx;
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if (len < (int)sizeof(struct StartMediaTransmission)) {
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#ifdef LIBALIAS_DEBUG
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fprintf(stderr,
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"PacketAlias/Skinny: Not a skinny packet,StartMediaTx Message\n");
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#endif
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return;
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}
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if (lip == -1) {
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#ifdef LIBALIAS_DEBUG
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fprintf(stderr,
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"PacketAlias/Skinny: received a"
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" packet,StartMediaTx Message before"
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" packet,OpnRcvChnAckMsg\n"
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#endif
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return;
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}
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#ifdef LIBALIAS_DEBUG
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fprintf(stderr,
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"PacketAlias/Skinny: Received start media trans msg\n");
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#endif
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startmedia_tx = (struct StartMediaTransmission *)&sd->msgId;
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alias_skinny_startmedia(startmedia_tx, pip, tc, lnk, lip, direction);
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break;
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}
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default:
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break;
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}
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/* Place the pointer at the next message in the packet. */
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dlen -= len + (skinny_hdr_len - sizeof(msgId));
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sd = (struct skinny_header *)(((char *)&sd->msgId) + len);
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}
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}
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