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-rw-r--r--lib/libalias/alias_skinny.c338
1 files changed, 338 insertions, 0 deletions
diff --git a/lib/libalias/alias_skinny.c b/lib/libalias/alias_skinny.c
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+/*-
+ * alias_skinny.c
+ *
+ * Copyright (c) 2002, 2003 MarcusCom, Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * Author: Joe Marcus Clarke <marcus@FreeBSD.org>
+ *
+ * $FreeBSD$
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in_systm.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <netinet/ip.h>
+#include <netinet/tcp.h>
+#include <netinet/udp.h>
+#include <unistd.h>
+
+#include "alias_local.h"
+
+/*
+ * alias_skinny.c handles the translation for the Cisco Skinny Station
+ * protocol. Skinny typically uses TCP port 2000 to set up calls between
+ * a Cisco Call Manager and a Cisco IP phone. When a phone comes on line,
+ * it first needs to register with the Call Manager. To do this it sends
+ * a registration message. This message contains the IP address of the
+ * IP phone. This message must then be translated to reflect our global
+ * IP address. Along with the registration message (and usually in the
+ * same packet), the phone sends an IP port message. This message indicates
+ * the TCP port over which it will communicate.
+ *
+ * When a call is placed from the phone, the Call Manager will send an
+ * Open Receive Channel message to the phone to let the caller know someone
+ * has answered. The phone then sends back an Open Receive Channel
+ * Acknowledgement. In this packet, the phone sends its IP address again,
+ * and the UDP port over which the voice traffic should flow. These values
+ * need translation. Right after the Open Receive Channel Acknowledgement,
+ * the Call Manager sends a Start Media Transmission message indicating the
+ * call is connected. This message contains the IP address and UDP port
+ * number of the remote (called) party. Once this message is translated, the
+ * call can commence. The called part sends the first UDP packet to the
+ * calling phone at the pre-arranged UDP port in the Open Receive Channel
+ * Acknowledgement.
+ *
+ * Skinny is a Cisco-proprietary protocol and is a trademark of Cisco Systems,
+ * Inc. All rights reserved.
+*/
+
+/* #define DEBUG 1 */
+
+/* Message types that need translating */
+#define REG_MSG 0x00000001
+#define IP_PORT_MSG 0x00000002
+#define OPNRCVCH_ACK 0x00000022
+#define START_MEDIATX 0x0000008a
+
+struct skinny_header {
+ u_int32_t len;
+ u_int32_t reserved;
+ u_int32_t msgId;
+};
+
+struct RegisterMessage {
+ u_int32_t msgId;
+ char devName[16];
+ u_int32_t uid;
+ u_int32_t instance;
+ u_int32_t ipAddr;
+ u_char devType;
+ u_int32_t maxStreams;
+};
+
+struct IpPortMessage {
+ u_int32_t msgId;
+ u_int32_t stationIpPort; /* Note: Skinny uses 32-bit port
+ * numbers */
+};
+
+struct OpenReceiveChannelAck {
+ u_int32_t msgId;
+ u_int32_t status;
+ u_int32_t ipAddr;
+ u_int32_t port;
+ u_int32_t passThruPartyID;
+};
+
+struct StartMediaTransmission {
+ u_int32_t msgId;
+ u_int32_t conferenceID;
+ u_int32_t passThruPartyID;
+ u_int32_t remoteIpAddr;
+ u_int32_t remotePort;
+ u_int32_t MSPacket;
+ u_int32_t payloadCap;
+ u_int32_t precedence;
+ u_int32_t silenceSuppression;
+ u_short maxFramesPerPacket;
+ u_int32_t G723BitRate;
+};
+
+typedef enum {
+ ClientToServer = 0,
+ ServerToClient = 1
+} ConvDirection;
+
+
+static int
+alias_skinny_reg_msg(struct RegisterMessage *reg_msg, struct ip *pip,
+ struct tcphdr *tc, struct alias_link *link,
+ ConvDirection direction)
+{
+ reg_msg->ipAddr = (u_int32_t) GetAliasAddress(link).s_addr;
+
+ tc->th_sum = 0;
+ tc->th_sum = TcpChecksum(pip);
+
+ return 0;
+}
+
+static int
+alias_skinny_startmedia(struct StartMediaTransmission *start_media,
+ struct ip *pip, struct tcphdr *tc,
+ struct alias_link *link, u_int32_t localIpAddr,
+ ConvDirection direction)
+{
+ struct in_addr dst, src;
+
+ dst.s_addr = start_media->remoteIpAddr;
+ src.s_addr = localIpAddr;
+
+ /* XXX I should probably handle in bound global translations as well. */
+
+ return 0;
+}
+
+static int
+alias_skinny_port_msg(struct IpPortMessage *port_msg, struct ip *pip,
+ struct tcphdr *tc, struct alias_link *link,
+ ConvDirection direction)
+{
+ port_msg->stationIpPort = (u_int32_t) ntohs(GetAliasPort(link));
+
+ tc->th_sum = 0;
+ tc->th_sum = TcpChecksum(pip);
+
+ return 0;
+}
+
+static int
+alias_skinny_opnrcvch_ack(struct OpenReceiveChannelAck *opnrcvch_ack,
+ struct ip * pip, struct tcphdr *tc,
+ struct alias_link *link, u_int32_t *localIpAddr,
+ ConvDirection direction)
+{
+ struct in_addr null_addr;
+ struct alias_link *opnrcv_link;
+ u_int32_t localPort;
+
+ *localIpAddr = (u_int32_t) opnrcvch_ack->ipAddr;
+ localPort = opnrcvch_ack->port;
+
+ null_addr.s_addr = INADDR_ANY;
+ opnrcv_link = FindUdpTcpOut(pip->ip_src, null_addr,
+ htons((u_short) opnrcvch_ack->port), 0,
+ IPPROTO_UDP, 1);
+ opnrcvch_ack->ipAddr = (u_int32_t) GetAliasAddress(opnrcv_link).s_addr;
+ opnrcvch_ack->port = (u_int32_t) ntohs(GetAliasPort(opnrcv_link));
+
+ tc->th_sum = 0;
+ tc->th_sum = TcpChecksum(pip);
+
+ return 0;
+}
+
+void
+AliasHandleSkinny(struct ip *pip, struct alias_link *link)
+{
+ int hlen, tlen, dlen;
+ struct tcphdr *tc;
+ u_int32_t msgId, len, t, lip;
+ struct skinny_header *sd;
+ int orig_len, skinny_hdr_len = sizeof(struct skinny_header);
+ ConvDirection direction;
+
+ tc = (struct tcphdr *) ((char *)pip + (pip->ip_hl << 2));
+ hlen = (pip->ip_hl + tc->th_off) << 2;
+ tlen = ntohs(pip->ip_len);
+ dlen = tlen - hlen;
+
+ sd = (struct skinny_header *) ((char *)pip + hlen);
+
+ /*
+ * XXX This direction is reserved for future use. I still need to
+ * handle the scenario where the call manager is on the inside, and
+ * the calling phone is on the global outside.
+ */
+ if (ntohs(tc->th_dport) == skinnyPort) {
+ direction = ClientToServer;
+ } else if (ntohs(tc->th_sport) == skinnyPort) {
+ direction = ServerToClient;
+ } else {
+#ifdef DEBUG
+ fprintf(stderr,
+ "PacketAlias/Skinny: Invalid port number, not a Skinny packet\n");
+#endif
+ return;
+ }
+
+ orig_len = dlen;
+ /*
+ * Skinny packets can contain many messages. We need to loop through
+ * the packet using len to determine message boundaries. This comes
+ * into play big time with port messages being in the same packet as
+ * register messages. Also, open receive channel acks are
+ * usually buried in a pakcet some 400 bytes long.
+ */
+ while (dlen >= skinny_hdr_len) {
+ len = (sd->len);
+ msgId = (sd->msgId);
+ t = len;
+
+ if (t < 0 || t > orig_len || t > dlen) {
+#ifdef DEBUG
+ fprintf(stderr,
+ "PacketAlias/Skinny: Not a skinny packet, invalid length \n");
+#endif
+ return;
+ }
+ switch (msgId) {
+ case REG_MSG:
+ {
+ struct RegisterMessage *reg_mesg;
+
+ if (len < sizeof(struct RegisterMessage)) {
+#ifdef DEBUG
+ fprintf(stderr,
+ "PacketAlias/Skinny: Not a skinny packet, bad registration message\n");
+#endif
+ return;
+ }
+ reg_mesg = (struct RegisterMessage *) & sd->msgId;
+#ifdef DEBUG
+ fprintf(stderr,
+ "PacketAlias/Skinny: Received a register message");
+#endif
+ alias_skinny_reg_msg(reg_mesg, pip, tc, link, direction);
+ }
+ break;
+ case IP_PORT_MSG:
+ {
+ struct IpPortMessage *port_mesg;
+ if (len < sizeof(struct IpPortMessage)) {
+#ifdef DEBUG
+ fprintf(stderr,
+ "PacketAlias/Skinny: Not a skinny packet, port message\n");
+#endif
+ return;
+ }
+#ifdef DEBUG
+ fprintf(stderr
+ "PacketAlias/Skinny: Received ipport message\n");
+#endif
+ port_mesg = (struct IpPortMessage *) & sd->msgId;
+ alias_skinny_port_msg(port_mesg, pip, tc, link, direction);
+ }
+ break;
+ case OPNRCVCH_ACK:
+ {
+ struct OpenReceiveChannelAck *opnrcvchn_ack;
+
+ if (len < sizeof(struct OpenReceiveChannelAck)) {
+#ifdef DEBUG
+ fprintf(stderr,
+ "PacketAlias/Skinny: Not a skinny packet, packet,OpnRcvChnAckMsg\n");
+#endif
+ return;
+ }
+#ifdef DEBUG
+ fprintf(stderr,
+ "PacketAlias/Skinny: Received open rcv channel msg\n");
+#endif
+ opnrcvchn_ack = (struct OpenReceiveChannelAck *) & sd->msgId;
+ alias_skinny_opnrcvch_ack(opnrcvchn_ack, pip, tc, link, &lip, direction);
+ }
+ break;
+ case START_MEDIATX:
+ {
+ struct StartMediaTransmission *startmedia_tx;
+
+ if (len < sizeof(struct StartMediaTransmission)) {
+#ifdef DEBUG
+ fprintf(stderr,
+ "PacketAlias/Skinny: Not a skinny packet,StartMediaTx Message\n");
+#endif
+ return;
+ }
+#ifdef DEBUG
+ fprintf(stderr,
+ "PacketAlias/Skinny: Received start media trans msg\n");
+#endif
+ startmedia_tx = (struct StartMediaTransmission *) & sd->msgId;
+ alias_skinny_startmedia(startmedia_tx, pip, tc, link, lip, direction);
+ }
+ break;
+ default:
+ break;
+ }
+ /* Place the pointer at the next message in the packet. */
+ dlen -= len + (skinny_hdr_len - sizeof(msgId));
+ sd = (struct skinny_header *) (((char *)&sd->msgId) + len);
+ }
+}
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