c6e57e046e
kernel module. LibAlias is not aware about checksum offloading, so the caller should provide checksum calculation. (The only current consumer is ng_nat(4)). When TCP packet internals has been changed and it requires checksum recalculation, a cookie is set in th_x2 field of TCP packet, to inform caller that it needs to recalculate checksum. This ugly hack would be removed when LibAlias is made more kernel friendly. Incremental checksum updates are left as is, since they don't conflict with offloading. Approved by: re (scottl)
371 lines
10 KiB
C
371 lines
10 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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#else
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include <arpa/inet.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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#include <netinet/udp.h>
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#ifdef _KERNEL
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#include <netinet/libalias/alias.h>
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#include <netinet/libalias/alias_local.h>
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#else
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#include "alias_local.h"
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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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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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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 pakcet 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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#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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