[mgcp] Rename the source to mgcp_main.c

1 files changed, 1243 insertions, 0 deletions

diff --git a/openbsc/src/mgcp/mgcp_main.c b/openbsc/src/mgcp/mgcp_main.c
new file mode 100644
index 000000000..d89eb8399
--- /dev/null
+++ b/openbsc/src/mgcp/mgcp_main.c
@@ -0,0 +1,1243 @@
+/* A Media Gateway Control Protocol Media Gateway: RFC 3435 */
+
+/*
+ * (C) 2009 by Holger Hans Peter Freyther <zecke@selfish.org>
+ * (C) 2009 by on-waves.com
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+
+#include <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <limits.h>
+#include <unistd.h>
+
+#include <sys/socket.h>
+#include <arpa/inet.h>
+
+#include <openbsc/debug.h>
+#include <openbsc/msgb.h>
+#include <openbsc/talloc.h>
+#include <openbsc/gsm_data.h>
+#include <openbsc/select.h>
+#include <openbsc/mgcp.h>
+#include <openbsc/telnet_interface.h>
+
+#include <vty/command.h>
+#include <vty/vty.h>
+
+/* this is here for the vty... it will never be called */
+void subscr_put() { abort(); }
+
+#define _GNU_SOURCE
+#include <getopt.h>
+
+#warning "Make use of the rtp proxy code"
+
+static int source_port = 2427;
+static const char *local_ip = NULL;
+static const char *source_addr = "0.0.0.0";
+static struct bsc_fd bfd;
+static unsigned int number_endpoints = 0;
+static const char *bts_ip = NULL;
+static struct in_addr bts_in;
+static int first_request = 1;
+static const char *audio_name = "GSM-EFR/8000";
+static int audio_payload = 97;
+static int audio_loop = 0;
+static int early_bind = 0;
+
+static char *forward_ip = NULL;
+static int forward_port = 0;
+static char *config_file = "mgcp.cfg";
+
+/* used by msgb and mgcp */
+void *tall_bsc_ctx = NULL;
+
+enum mgcp_connection_mode {
+	MGCP_CONN_NONE = 0,
+	MGCP_CONN_RECV_ONLY = 1,
+	MGCP_CONN_SEND_ONLY = 2,
+	MGCP_CONN_RECV_SEND = MGCP_CONN_RECV_ONLY | MGCP_CONN_SEND_ONLY,
+};
+
+enum {
+	DEST_NETWORK = 0,
+	DEST_BTS = 1,
+};
+
+enum {
+	PROTO_RTP,
+	PROTO_RTCP,
+};
+
+#define CI_UNUSED 0
+static unsigned int last_call_id = 0;
+
+struct mgcp_endpoint {
+	int ci;
+	char *callid;
+	char *local_options;
+	int conn_mode;
+
+	/* the local rtp port we are binding to */
+	int rtp_port;
+
+	/*
+	 * RTP mangling:
+	 *  - we get RTP and RTCP to us and need to forward to the BTS
+	 *  - we get RTP and RTCP from the BTS and forward to the network
+	 */
+	struct bsc_fd local_rtp;
+	struct bsc_fd local_rtcp;
+
+	struct in_addr remote;
+	struct in_addr bts;
+
+	/* in network byte order */
+	int net_rtp, net_rtcp;
+	int bts_rtp, bts_rtcp;
+};
+
+static struct mgcp_endpoint *endpoints = NULL;
+#define ENDPOINT_NUMBER(endp) abs(endp - endpoints)
+
+/**
+ * Macro for tokenizing MGCP messages and SDP in one go.
+ *
+ */
+#define MSG_TOKENIZE_START \
+	line_start = 0;						\
+	for (i = 0; i < msgb_l3len(msg); ++i) {			\
+		/* we have a line end */			\
+		if (msg->l3h[i] == '\n') {			\
+			/* skip the first line */		\
+			if (line_start == 0) {			\
+				line_start = i + 1;		\
+				continue;			\
+			}					\
+								\
+			/* check if we have a proper param */	\
+			if (i - line_start == 1 && msg->l3h[line_start] == '\r') { \
+			} else if (i - line_start > 2		\
+			    && islower(msg->l3h[line_start])	\
+			    && msg->l3h[line_start + 1] == '=') { \
+			} else if (i - line_start < 3		\
+			    || msg->l3h[line_start + 1] != ':'	\
+			    || msg->l3h[line_start + 2] != ' ')	\
+				goto error;			\
+								\
+			msg->l3h[i] = '\0';			\
+			if (msg->l3h[i-1] == '\r')		\
+				msg->l3h[i-1] = '\0';
+
+#define MSG_TOKENIZE_END \
+			line_start = i + 1; \
+		}			    \
+	}
+
+
+struct mgcp_msg_ptr {
+	unsigned int start;
+	unsigned int length;
+};
+
+struct mgcp_request {
+	char *name;
+	void (*handle_request) (struct msgb *msg, struct sockaddr_in *source);
+	char *debug_name;
+};
+
+#define MGCP_REQUEST(NAME, REQ, DEBUG_NAME) \
+	{ .name = NAME, .handle_request = REQ, .debug_name = DEBUG_NAME },
+
+static void handle_audit_endpoint(struct msgb *msg, struct sockaddr_in *source);
+static void handle_create_con(struct msgb *msg, struct sockaddr_in *source);
+static void handle_delete_con(struct msgb *msg, struct sockaddr_in *source);
+static void handle_modify_con(struct msgb *msg, struct sockaddr_in *source);
+
+static int generate_call_id()
+{
+	int i;
+
+	/* use the call id */
+	++last_call_id;
+
+	/* handle wrap around */
+	if (last_call_id == CI_UNUSED)
+		++last_call_id;
+
+	/* callstack can only be of size number_of_endpoints */
+	/* verify that the call id is free, e.g. in case of overrun */
+	for (i = 1; i < number_endpoints; ++i)
+		if (endpoints[i].ci == last_call_id)
+			return generate_call_id();
+
+	return last_call_id;
+}
+
+/* FIXIME/TODO: need to have a list of pending transactions and check that */
+static unsigned int generate_transaction_id()
+{
+	return abs(rand());
+}
+
+static int _send(int fd, struct in_addr *addr, int port, char *buf, int len)
+{
+	struct sockaddr_in out;
+	out.sin_family = AF_INET;
+	out.sin_port = port;
+	memcpy(&out.sin_addr, addr, sizeof(*addr));
+
+	return sendto(fd, buf, len, 0, (struct sockaddr *)&out, sizeof(out));
+}
+
+/*
+ * There is data coming. We will have to figure out if it
+ * came from the BTS or the MediaGateway of the MSC. On top
+ * of that we need to figure out if it was RTP or RTCP.
+ *
+ * Currently we do not communicate with the BSC so we have
+ * no idea where the BTS is listening for RTP and need to
+ * do the classic routing trick. Wait for the first packet
+ * from the BTS and then go ahead.
+ */
+static int rtp_data_cb(struct bsc_fd *fd, unsigned int what)
+{
+	char buf[4096];
+	struct sockaddr_in addr;
+	socklen_t slen = sizeof(addr);
+	struct mgcp_endpoint *endp;
+	int rc, dest, proto;
+
+	endp = (struct mgcp_endpoint *) fd->data;
+
+	rc = recvfrom(fd->fd, &buf, sizeof(buf), 0,
+			    (struct sockaddr *) &addr, &slen);
+	if (rc < 0) {
+		DEBUGP(DMGCP, "Failed to receive message on: 0x%x\n",
+			ENDPOINT_NUMBER(endp));
+		return -1;
+	}
+
+	/* do not forward aynthing... maybe there is a packet from the bts */
+	if (endp->ci == CI_UNUSED) {
+		DEBUGP(DMGCP, "Unknown message on endpoint: 0x%x\n", ENDPOINT_NUMBER(endp));
+		return -1;
+	}
+
+	/*
+	 * Figure out where to forward it to. This code assumes that we
+	 * have received the Connection Modify and know who is a legitimate
+	 * partner. According to the spec we could attempt to forward even
+	 * after the Create Connection but we will not as we are not really
+	 * able to tell if this is legitimate.
+	 */
+	#warning "Slight spec violation. With connection mode recvonly we should attempt to forward."
+	dest = memcmp(&addr.sin_addr, &endp->remote, sizeof(addr.sin_addr)) == 0 &&
+                    (endp->net_rtp == addr.sin_port || endp->net_rtcp == addr.sin_port)
+			? DEST_BTS : DEST_NETWORK;
+	proto = fd == &endp->local_rtp ? PROTO_RTP : PROTO_RTCP;
+
+	/* We have no idea who called us, maybe it is the BTS. */
+	if (dest == DEST_NETWORK && (endp->bts_rtp == 0 || forward_ip)) {
+		/* it was the BTS... */
+		if (!bts_ip || memcmp(&addr.sin_addr, &bts_in, sizeof(bts_in)) == 0) {
+			if (fd == &endp->local_rtp) {
+				endp->bts_rtp = addr.sin_port;
+			} else {
+				endp->bts_rtcp = addr.sin_port;
+			}
+
+			endp->bts = addr.sin_addr;
+			DEBUGP(DMGCP, "Found BTS for endpoint: 0x%x on port: %d/%d\n",
+				ENDPOINT_NUMBER(endp), ntohs(endp->bts_rtp), ntohs(endp->bts_rtcp));
+		}
+	}
+
+	/* dispatch */
+	if (audio_loop)
+		dest = !dest;
+
+	if (dest == DEST_NETWORK) {
+		return _send(fd->fd, &endp->remote,
+			     proto == PROTO_RTP ? endp->net_rtp : endp->net_rtcp,
+			     buf, rc);
+	} else {
+		return _send(fd->fd, &endp->bts,
+			     proto == PROTO_RTP ? endp->bts_rtp : endp->bts_rtcp,
+			     buf, rc);
+	}
+}
+
+static int create_bind(struct bsc_fd *fd, int port)
+{
+	struct sockaddr_in addr;
+	int on = 1;
+
+	fd->fd = socket(AF_INET, SOCK_DGRAM, 0);
+	if (fd->fd < 0)
+		return -1;
+
+	setsockopt(fd->fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
+	memset(&addr, 0, sizeof(addr));
+	addr.sin_family = AF_INET;
+	addr.sin_port = htons(port);
+	inet_aton(source_addr, &addr.sin_addr);
+
+	if (bind(fd->fd, (struct sockaddr *) &addr, sizeof(addr)) < 0)
+		return -1;
+
+	return 0;
+}
+
+static int bind_rtp(struct mgcp_endpoint *endp)
+{
+	if (create_bind(&endp->local_rtp, endp->rtp_port) != 0) {
+		DEBUGP(DMGCP, "Failed to create RTP port: %d on 0x%x\n",
+		       endp->rtp_port, ENDPOINT_NUMBER(endp));
+		goto cleanup0;
+	}
+
+	if (create_bind(&endp->local_rtcp, endp->rtp_port + 1) != 0) {
+		DEBUGP(DMGCP, "Failed to create RTCP port: %d on 0x%x\n",
+		       endp->rtp_port + 1, ENDPOINT_NUMBER(endp));
+		goto cleanup1;
+	}
+
+	endp->local_rtp.cb = rtp_data_cb;
+	endp->local_rtp.data = endp;
+	endp->local_rtp.when = BSC_FD_READ;
+	if (bsc_register_fd(&endp->local_rtp) != 0) {
+		DEBUGP(DMGCP, "Failed to register RTP port %d on 0x%x\n",
+			endp->rtp_port, ENDPOINT_NUMBER(endp));
+		goto cleanup2;
+	}
+
+	endp->local_rtcp.cb = rtp_data_cb;
+	endp->local_rtcp.data = endp;
+	endp->local_rtcp.when = BSC_FD_READ;
+	if (bsc_register_fd(&endp->local_rtcp) != 0) {
+		DEBUGP(DMGCP, "Failed to register RTCP port %d on 0x%x\n",
+			endp->rtp_port + 1, ENDPOINT_NUMBER(endp));
+		goto cleanup3;
+	}
+
+	return 0;
+
+cleanup3:
+	bsc_unregister_fd(&endp->local_rtp);
+cleanup2:
+	close(endp->local_rtcp.fd);
+	endp->local_rtcp.fd = -1;
+cleanup1:
+	close(endp->local_rtp.fd);
+	endp->local_rtp.fd = -1;
+cleanup0:
+	return -1;
+}
+
+/*
+ * array of function pointers for handling various
+ * messages. In the future this might be binary sorted
+ * for performance reasons.
+ */
+static const struct mgcp_request mgcp_requests [] = {
+	MGCP_REQUEST("AUEP", handle_audit_endpoint, "AuditEndpoint")
+	MGCP_REQUEST("CRCX", handle_create_con, "CreateConnection")
+	MGCP_REQUEST("DLCX", handle_delete_con, "DeleteConnection")
+	MGCP_REQUEST("MDCX", handle_modify_con, "ModifiyConnection")
+};
+
+static void send_response_with_data(int code, const char *msg, const char *trans,
+				    const char *data, struct sockaddr_in *source)
+{
+	char buf[4096];
+	int len;
+
+	if (data) {
+		len = snprintf(buf, sizeof(buf), "%d %s\n%s", code, trans, data);
+	} else {
+		len = snprintf(buf, sizeof(buf), "%d %s\n", code, trans);
+	}
+	DEBUGP(DMGCP, "Sending response: code: %d for '%s'\n", code, msg);
+
+	sendto(bfd.fd, buf, len, 0, (struct sockaddr *)source, sizeof(*source));
+}
+
+static void send_response(int code, const char *msg, const char *trans, struct sockaddr_in *source)
+{
+	send_response_with_data(code, msg, trans, NULL, source);
+}
+
+static void send_with_sdp(struct mgcp_endpoint *endp, const char *msg, const char *trans_id, struct sockaddr_in *source)
+{
+	const char *addr = local_ip;
+	char sdp_record[4096];
+
+	if (!addr)
+		addr = source_addr;
+
+	snprintf(sdp_record, sizeof(sdp_record) - 1,
+			"I: %d\n\n"
+			"v=0\r\n"
+			"c=IN IP4 %s\r\n"
+			"m=audio %d RTP/AVP %d\r\n"
+			"a=rtpmap:%d %s\r\n",
+			endp->ci, addr, endp->rtp_port,
+			audio_payload, audio_payload, audio_name);
+	return send_response_with_data(200, msg, trans_id, sdp_record, source);
+}
+
+/* send a static record */
+static void send_rsip(struct sockaddr_in *source)
+{
+	char reset[4096];
+	int len, rc;
+
+	len = snprintf(reset, sizeof(reset) - 1,
+			"RSIP %u *@mgw MGCP 1.0\n"
+			"RM: restart\n", generate_transaction_id());
+	rc = sendto(bfd.fd, reset, len, 0, (struct sockaddr *) source, sizeof(*source));
+	if (rc < 0) {
+		DEBUGP(DMGCP, "Failed to send RSIP: %d\n", rc);
+	}
+}
+
+/*
+ * handle incoming messages:
+ *   - this can be a command (four letters, space, transaction id)
+ *   - or a response (three numbers, space, transaction id)
+ */
+static void handle_message(struct msgb *msg, struct sockaddr_in *source)
+{
+        int code;
+
+	if (msg->len < 4) {
+		DEBUGP(DMGCP, "mgs too short: %d\n", msg->len);
+		return;
+	}
+
+        /* attempt to treat it as a response */
+        if (sscanf((const char *)&msg->data[0], "%3d %*s", &code) == 1) {
+		DEBUGP(DMGCP, "Response: Code: %d\n", code);
+	} else {
+		int i, handled = 0;
+		msg->l3h = &msg->l2h[4];
+		for (i = 0; i < ARRAY_SIZE(mgcp_requests); ++i)
+			if (strncmp(mgcp_requests[i].name, (const char *) &msg->data[0], 4) == 0) {
+				handled = 1;
+				mgcp_requests[i].handle_request(msg, source);
+			}
+		if (!handled) {
+			DEBUGP(DMGCP, "MSG with type: '%.4s' not handled\n", &msg->data[0]);
+		}
+	}
+}
+
+/* string tokenizer for the poor */
+static int find_msg_pointers(struct msgb *msg, struct mgcp_msg_ptr *ptrs, int ptrs_length)
+{
+	int i, found = 0;
+
+	int whitespace = 1;
+	for (i = 0; i < msgb_l3len(msg) && ptrs_length > 0; ++i) {
+		/* if we have a space we found an end */
+		if (msg->l3h[i]	== ' ' || msg->l3h[i] == '\r' || msg->l3h[i] == '\n') {
+			if (!whitespace) {
+				++found;
+				whitespace = 1;
+				ptrs->length = i - ptrs->start - 1;
+				++ptrs;
+				--ptrs_length;
+			} else {
+			    /* skip any number of whitespace */
+			}
+
+			/* line end... stop */
+			if (msg->l3h[i] == '\r' || msg->l3h[i] == '\n')
+				break;
+		} else if (msg->l3h[i] == '\r' || msg->l3h[i] == '\n') {
+			/* line end, be done */
+			break;
+		} else if (whitespace) {
+			whitespace = 0;
+			ptrs->start = i;
+		}
+	}
+
+	if (ptrs_length == 0)
+		return -1;
+	return found;
+}
+
+static struct mgcp_endpoint *find_endpoint(const char *mgcp)
+{
+	char *endptr = NULL;
+	unsigned int gw = INT_MAX;
+
+	gw = strtoul(mgcp, &endptr, 16);
+	if (gw == 0 || gw >= number_endpoints || strcmp(endptr, "@mgw") != 0) {
+		DEBUGP(DMGCP, "Not able to find endpoint: '%s'\n", mgcp);
+		return NULL;
+	}
+
+	return &endpoints[gw];
+}
+
+static int analyze_header(struct msgb *msg, struct mgcp_msg_ptr *ptr, int size,
+			  const char **transaction_id, struct mgcp_endpoint **endp)
+{
+	int found;
+
+	if (size < 3) {
+		DEBUGP(DMGCP, "Not enough space in ptr\n");
+		return -1;
+	}
+
+	found = find_msg_pointers(msg, ptr, size);
+
+	if (found < 3) {
+		DEBUGP(DMGCP, "Gateway: Not enough params. Found: %d\n", found);
+		return -1;
+	}
+
+	/*
+	 * replace the space with \0. the main method gurantess that
+	 * we still have + 1 for null termination
+	 */
+	msg->l3h[ptr[3].start + ptr[3].length + 1] = '\0';
+	msg->l3h[ptr[2].start + ptr[2].length + 1] = '\0';
+	msg->l3h[ptr[1].start + ptr[1].length + 1] = '\0';
+	msg->l3h[ptr[0].start + ptr[0].length + 1] = '\0';
+
+	if (strncmp("1.0", (const char *)&msg->l3h[ptr[3].start], 3) != 0
+	    || strncmp("MGCP", (const char *)&msg->l3h[ptr[2].start], 4) != 0) {
+		DEBUGP(DMGCP, "Wrong MGCP version. Not handling: '%s' '%s'\n",
+			(const char *)&msg->l3h[ptr[3].start],
+			(const char *)&msg->l3h[ptr[2].start]);
+		return -1;
+	}
+
+	*transaction_id = (const char *)&msg->l3h[ptr[0].start];
+	*endp = find_endpoint((const char *)&msg->l3h[ptr[1].start]);
+	return *endp == NULL;
+}
+
+static int verify_call_id(const struct mgcp_endpoint *endp,
+			  const char *callid)
+{
+	if (strcmp(endp->callid, callid) != 0) {
+		DEBUGP(DMGCP, "CallIDs does not match on 0x%x. '%s' != '%s'\n",
+			ENDPOINT_NUMBER(endp), endp->callid, callid);
+		return -1;
+	}
+
+	return 0;
+}
+
+static int verify_ci(const struct mgcp_endpoint *endp,
+		     const char *ci)
+{
+	if (atoi(ci) != endp->ci) {
+		DEBUGP(DMGCP, "ConnectionIdentifiers do not match on 0x%x. %d != %s\n",
+			ENDPOINT_NUMBER(endp), endp->ci, ci);
+		return -1;
+	}
+
+	return 0;
+}
+
+static void handle_audit_endpoint(struct msgb *msg, struct sockaddr_in *source)
+{
+	struct mgcp_msg_ptr data_ptrs[6];
+	int found, response;
+	const char *trans_id;
+	struct mgcp_endpoint *endp;
+
+	found = analyze_header(msg, data_ptrs, ARRAY_SIZE(data_ptrs), &trans_id, &endp);
+	if (found != 0)
+	    response = 500;
+	else
+	    response = 200;
+
+	return send_response(response, "AUEP", trans_id, source);
+}
+
+static int parse_conn_mode(const char* msg, int *conn_mode)
+{
+	int ret = 0;
+	if (strcmp(msg, "recvonly") == 0)
+		*conn_mode = MGCP_CONN_RECV_ONLY;
+	else if (strcmp(msg, "sendrecv") == 0)
+		*conn_mode = MGCP_CONN_RECV_SEND;
+	else {
+		DEBUGP(DMGCP, "Unknown connection mode: '%s'\n", msg);
+		ret = -1;
+	}
+
+	return ret;
+}
+
+static void handle_create_con(struct msgb *msg, struct sockaddr_in *source)
+{
+	struct mgcp_msg_ptr data_ptrs[6];
+	int found, i, line_start;
+	const char *trans_id;
+	struct mgcp_endpoint *endp;
+	int error_code = 500;
+
+	found = analyze_header(msg, data_ptrs, ARRAY_SIZE(data_ptrs), &trans_id, &endp);
+	if (found != 0)
+		return send_response(500, "CRCX", trans_id, source);
+
+	if (endp->ci != CI_UNUSED) {
+		DEBUGP(DMGCP, "Endpoint is already used. 0x%x\n", ENDPOINT_NUMBER(endp));
+		return send_response(500, "CRCX", trans_id, source);
+	}
+
+	/* parse CallID C: and LocalParameters L: */
+	MSG_TOKENIZE_START
+	switch (msg->l3h[line_start]) {
+	case 'L':
+		endp->local_options = talloc_strdup(endpoints,
+			(const char *)&msg->l3h[line_start + 3]);
+		break;
+	case 'C':
+		endp->callid = talloc_strdup(endpoints,
+			(const char *)&msg->l3h[line_start + 3]);
+		break;
+	case 'M':
+		if (parse_conn_mode((const char *)&msg->l3h[line_start + 3],
+			    &endp->conn_mode) != 0) {
+		    error_code = 517;
+		    goto error2;
+		}
+		break;
+	default:
+		DEBUGP(DMGCP, "Unhandled option: '%c'/%d on 0x%x\n",
+			msg->l3h[line_start], msg->l3h[line_start],
+			ENDPOINT_NUMBER(endp));
+		break;
+	}
+	MSG_TOKENIZE_END
+
+	/* initialize */
+	endp->net_rtp = endp->net_rtcp = endp->bts_rtp = endp->bts_rtcp = 0;
+
+	/* set to zero until we get the info */
+	memset(&endp->remote, 0, sizeof(endp->remote));
+
+	/* bind to the port now */
+	endp->rtp_port = rtp_calculate_port(ENDPOINT_NUMBER(endp), rtp_base_port);
+	if (!early_bind && bind_rtp(endp) != 0)
+		goto error2;
+
+	/* assign a local call identifier or fail */
+	endp->ci = generate_call_id();
+	if (endp->ci == CI_UNUSED)
+		goto error2;
+
+	DEBUGP(DMGCP, "Creating endpoint on: 0x%x CI: %u port: %u\n",
+		ENDPOINT_NUMBER(endp), endp->ci, endp->rtp_port);
+	return send_with_sdp(endp, "CRCX", trans_id, source);
+error:
+	DEBUGP(DMGCP, "Malformed line: %s on 0x%x with: line_start: %d %d\n",
+		    hexdump(msg->l3h, msgb_l3len(msg)),
+		    ENDPOINT_NUMBER(endp), line_start, i);
+	return send_response(error_code, "CRCX", trans_id, source);
+
+error2:
+	DEBUGP(DMGCP, "Resource error on 0x%x\n", ENDPOINT_NUMBER(endp));
+	return send_response(error_code, "CRCX", trans_id, source);
+}
+
+static void handle_modify_con(struct msgb *msg, struct sockaddr_in *source)
+{
+	struct mgcp_msg_ptr data_ptrs[6];
+	int found, i, line_start;
+	const char *trans_id;
+	struct mgcp_endpoint *endp;
+	int error_code = 500;
+
+	found = analyze_header(msg, data_ptrs, ARRAY_SIZE(data_ptrs), &trans_id, &endp);
+	if (found != 0)
+		return send_response(error_code, "MDCX", trans_id, source);
+
+	if (endp->ci == CI_UNUSED) {
+		DEBUGP(DMGCP, "Endpoint is not holding a connection. 0x%x\n", ENDPOINT_NUMBER(endp));
+		return send_response(error_code, "MDCX", trans_id, source);
+	}
+
+	MSG_TOKENIZE_START
+	switch (msg->l3h[line_start]) {
+	case 'C': {
+		if (verify_call_id(endp, (const char *)&msg->l3h[line_start + 3]) != 0)
+			goto error3;
+		break;
+	}
+	case 'I': {
+		if (verify_ci(endp, (const char *)&msg->l3h[line_start + 3]) != 0)
+			goto error3;
+		break;
+	}
+	case 'L':
+		/* skip */
+		break;
+	case 'M':
+		if (parse_conn_mode((const char *)&msg->l3h[line_start + 3],
+			    &endp->conn_mode) != 0) {
+		    error_code = 517;
+		    goto error3;
+		}
+		break;
+	case '\0':
+		/* SDP file begins */
+		break;
+	case 'a':
+	case 'o':
+	case 's':
+	case 't':
+	case 'v':
+		/* skip these SDP attributes */
+		break;
+	case 'm': {
+		int port;
+		const char *param = (const char *)&msg->l3h[line_start];
+
+		if (sscanf(param, "m=audio %d RTP/AVP %*d", &port) == 1) {
+			endp->net_rtp = htons(port);
+			endp->net_rtcp = htons(port + 1);
+		}
+		break;
+	}
+	case 'c': {
+		char ipv4[16];
+		const char *param = (const char *)&msg->l3h[line_start];
+
+		if (sscanf(param, "c=IN IP4 %15s", ipv4) == 1) {
+			inet_aton(ipv4, &endp->remote);
+		}
+		break;
+	}
+	default:
+		DEBUGP(DMGCP, "Unhandled option: '%c'/%d on 0x%x\n",
+			msg->l3h[line_start], msg->l3h[line_start],
+			ENDPOINT_NUMBER(endp));
+		break;
+	}
+	MSG_TOKENIZE_END
+
+	/* modify */
+	DEBUGP(DMGCP, "Modified endpoint on: 0x%x Server: %s:%u\n",
+		ENDPOINT_NUMBER(endp), inet_ntoa(endp->remote), endp->net_rtp);
+	return send_with_sdp(endp, "MDCX", trans_id, source);
+
+error:
+	DEBUGP(DMGCP, "Malformed line: %s on 0x%x with: line_start: %d %d %d\n",
+		    hexdump(msg->l3h, msgb_l3len(msg)),
+		    ENDPOINT_NUMBER(endp), line_start, i, msg->l3h[line_start]);
+	return send_response(error_code, "MDCX", trans_id, source);
+
+error3:
+	return send_response(error_code, "MDCX", trans_id, source);
+}
+
+static void handle_delete_con(struct msgb *msg, struct sockaddr_in *source)
+{
+	struct mgcp_msg_ptr data_ptrs[6];
+	int found, i, line_start;
+	const char *trans_id;
+	struct mgcp_endpoint *endp;
+	int error_code = 500;
+
+	found = analyze_header(msg, data_ptrs, ARRAY_SIZE(data_ptrs), &trans_id, &endp);
+	if (found != 0)
+		return send_response(error_code, "DLCX", trans_id, source);
+
+	if (endp->ci == CI_UNUSED) {
+		DEBUGP(DMGCP, "Endpoint is not used. 0x%x\n", ENDPOINT_NUMBER(endp));
+		return send_response(error_code, "DLCX", trans_id, source);
+	}
+
+	MSG_TOKENIZE_START
+	switch (msg->l3h[line_start]) {
+	case 'C': {
+		if (verify_call_id(endp, (const char *)&msg->l3h[line_start + 3]) != 0)
+			goto error3;
+		break;
+	}
+	case 'I': {
+		if (verify_ci(endp, (const char *)&msg->l3h[line_start + 3]) != 0)
+			goto error3;
+		break;
+	}
+	default:
+		DEBUGP(DMGCP, "Unhandled option: '%c'/%d on 0x%x\n",
+			msg->l3h[line_start], msg->l3h[line_start],
+			ENDPOINT_NUMBER(endp));
+		break;
+	}
+	MSG_TOKENIZE_END
+
+
+	/* free the connection */
+	DEBUGP(DMGCP, "Deleting endpoint on: 0x%x\n", ENDPOINT_NUMBER(endp));
+	endp->ci= CI_UNUSED;
+	talloc_free(endp->callid);
+	talloc_free(endp->local_options);
+
+	if (!early_bind) {
+		bsc_unregister_fd(&endp->local_rtp);
+		bsc_unregister_fd(&endp->local_rtcp);
+	}
+
+	endp->net_rtp = endp->net_rtcp = endp->bts_rtp = endp->bts_rtcp = 0;
+
+	return send_response(250, "DLCX", trans_id, source);
+
+error:
+	DEBUGP(DMGCP, "Malformed line: %s on 0x%x with: line_start: %d %d\n",
+		    hexdump(msg->l3h, msgb_l3len(msg)),
+		    ENDPOINT_NUMBER(endp), line_start, i);
+	return send_response(error_code, "DLCX", trans_id, source);
+
+error3:
+	return send_response(error_code, "DLCX", trans_id, source);
+}
+
+static void print_help()
+{
+	printf("Some useful help...\n");
+	printf(" -h --help is printing this text.\n");
+	printf(" -c --config-file filename The config file to use.\n");
+}
+
+static void handle_options(int argc, char** argv)
+{
+	while (1) {
+		int option_index = 0, c;
+		static struct option long_options[] = {
+			{"help", 0, 0, 'h'},
+			{"config-file", 1, 0, 'c'},
+			{0, 0, 0, 0},
+		};
+
+		c = getopt_long(argc, argv, "hc:", long_options, &option_index);
+
+		if (c == -1)
+			break;
+
+		switch(c) {
+		case 'h':
+			print_help();
+			exit(0);
+			break;
+		case 'c':
+			config_file = talloc_strdup(tall_bsc_ctx, optarg);
+			break;
+		default:
+			/* ignore */
+			break;
+		};
+	}
+}
+
+static int read_call_agent(struct bsc_fd *fd, unsigned int what)
+{
+	struct sockaddr_in addr;
+	socklen_t slen = sizeof(addr);
+	struct msgb *msg;
+
+	msg = (struct msgb *) fd->data;
+
+	/* read one less so we can use it as a \0 */
+	int rc = recvfrom(bfd.fd, msg->data, msg->data_len - 1, 0,
+		(struct sockaddr *) &addr, &slen);
+	if (rc < 0) {
+		perror("Gateway failed to read");
+		return -1;
+	} else if (slen > sizeof(addr)) {
+		fprintf(stderr, "Gateway received message from outerspace: %d %d\n",
+			slen, sizeof(addr));
+		return -1;
+	}
+
+	if (first_request) {
+		first_request = 0;
+		send_rsip(&addr);
+		return 0;
+        }
+
+	/* handle message now */
+	msg->l2h = msgb_put(msg, rc);
+	handle_message(msg, &addr);
+	msgb_reset(msg);
+	return 0;
+}
+
+/*
+ * vty code for mgcp below
+ */
+struct cmd_node mgcp_node = {
+	MGCP_NODE,
+	"%s(mgcp)#",
+	1,
+};
+
+static int config_write_mgcp(struct vty *vty)
+{
+	vty_out(vty, "mgcp%s", VTY_NEWLINE);
+	if (local_ip)
+		vty_out(vty, " local ip %s%s", local_ip, VTY_NEWLINE);
+	if (bts_ip)
+		vty_out(vty, "  bts ip %s%s", bts_ip, VTY_NEWLINE);
+	vty_out(vty, "  bind ip %s%s", source_addr, VTY_NEWLINE);
+	vty_out(vty, "  bind port %u%s", source_port, VTY_NEWLINE);
+	vty_out(vty, "  bind early %u%s", !!early_bind, VTY_NEWLINE);
+	vty_out(vty, "  rtp base %u%s", rtp_base_port, VTY_NEWLINE);
+	vty_out(vty, "  sdp audio payload number %u%s", audio_payload, VTY_NEWLINE);
+	vty_out(vty, "  sdp audio payload name %s%s", audio_name, VTY_NEWLINE);
+	vty_out(vty, "  loop %u%s", !!audio_loop, VTY_NEWLINE);
+	vty_out(vty, "  endpoints %u%s", number_endpoints, VTY_NEWLINE);
+	if (forward_ip)
+		vty_out(vty, " forward audio ip %s%s", forward_ip, VTY_NEWLINE);
+	if (forward_port != 0)
+		vty_out(vty, " forward audio port %d%s", forward_port, VTY_NEWLINE);
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(show_mcgp, show_mgcp_cmd, "show mgcp",
+      SHOW_STR "Display information about the MGCP Media Gateway")
+{
+	int i;
+
+	vty_out(vty, "MGCP is up and running with %u endpoints:%s", number_endpoints - 1, VTY_NEWLINE);
+	for (i = 1; i < number_endpoints; ++i) {
+		struct mgcp_endpoint *endp = &endpoints[i];
+		vty_out(vty, " Endpoint 0x%.2x: CI: %d net: %u/%u bts: %u/%u%s",
+			i, endp->ci,
+			ntohs(endp->net_rtp), ntohs(endp->net_rtcp),
+			ntohs(endp->bts_rtp), ntohs(endp->bts_rtcp), VTY_NEWLINE);
+	}
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_mgcp,
+      cfg_mgcp_cmd,
+      "mgcp",
+      "Configure the MGCP")
+{
+	vty->node = MGCP_NODE;
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_mgcp_local_ip,
+      cfg_mgcp_local_ip_cmd,
+      "local ip IP",
+      "Set the IP to be used in SDP records")
+{
+	local_ip = talloc_strdup(tall_bsc_ctx, argv[0]);
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_mgcp_bts_ip,
+      cfg_mgcp_bts_ip_cmd,
+      "bts ip IP",
+      "Set the IP of the BTS for RTP forwarding")
+{
+	bts_ip = talloc_strdup(tall_bsc_ctx, argv[0]);
+	inet_aton(bts_ip, &bts_in);
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_mgcp_bind_ip,
+      cfg_mgcp_bind_ip_cmd,
+      "bind ip IP",
+      "Bind the MGCP to this local addr")
+{
+	source_addr = talloc_strdup(tall_bsc_ctx, argv[0]);
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_mgcp_bind_port,
+      cfg_mgcp_bind_port_cmd,
+      "bind port <0-65534>",
+      "Bind the MGCP to this port")
+{
+	unsigned int port = atoi(argv[0]);
+	if (port > 65534) {
+		vty_out(vty, "%% wrong bind port '%s'%s", argv[0], VTY_NEWLINE);
+		return CMD_WARNING;
+	}
+
+	source_port = port;
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_mgcp_bind_early,
+      cfg_mgcp_bind_early_cmd,
+      "bind early (0|1)",
+      "Bind all RTP ports early")
+{
+	unsigned int bind = atoi(argv[0]);
+	if (bind != 0 && bind != 1) {
+		vty_out(vty, "%% param must be 0 or 1.%s", VTY_NEWLINE);
+		return CMD_WARNING;
+	}
+
+	early_bind = bind == 1;
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_mgcp_rtp_base_port,
+      cfg_mgcp_rtp_base_port_cmd,
+      "rtp base <0-65534>",
+      "Base port to use")
+{
+	unsigned int port = atoi(argv[0]);
+	if (port > 65534) {
+		vty_out(vty, "%% wrong base port '%s'%s", argv[0], VTY_NEWLINE);
+		return CMD_WARNING;
+	}
+
+	rtp_base_port = port;
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_mgcp_sdp_payload_number,
+      cfg_mgcp_sdp_payload_number_cmd,
+      "sdp audio payload number <1-255>",
+      "Set the audio codec to use")
+{
+	unsigned int payload = atoi(argv[0]);
+	if (payload > 255) {
+		vty_out(vty, "%% wrong payload number '%s'%s", argv[0], VTY_NEWLINE);
+		return CMD_WARNING;
+	}
+
+	audio_payload = payload;
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_mgcp_sdp_payload_name,
+      cfg_mgcp_sdp_payload_name_cmd,
+      "sdp audio payload name NAME",
+      "Set the audio name to use")
+{
+	audio_name = talloc_strdup(tall_bsc_ctx, argv[0]);
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_mgcp_loop,
+      cfg_mgcp_loop_cmd,
+      "loop (0|1)",
+      "Loop the audio")
+{
+	audio_loop = atoi(argv[0]);
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_mgcp_number_endp,
+      cfg_mgcp_number_endp_cmd,
+      "number endpoints <0-65534>",
+      "The number of endpoints to allocate. This is not dynamic.")
+{
+	/* + 1 as we start counting at one */
+	number_endpoints = atoi(argv[0]) + 1;
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_mgcp_forward_ip,
+      cfg_mgcp_forward_ip_cmd,
+      "forward audio ip IP",
+      "Forward packets from and to the IP. This disables most of the MGCP feature.")
+{
+	if (forward_ip)
+		talloc_free(forward_ip);
+	forward_ip = talloc_strdup(tall_bsc_ctx, argv[0]);
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_mgcp_forward_port,
+      cfg_mgcp_forward_port_cmd,
+      "forward audio port <1-15000>",
+      "Forward packets from and to the port. This disables most of the MGCP feature.")
+{
+	forward_port = atoi(argv[0]);
+	return CMD_SUCCESS;
+}
+
+int bsc_vty_init(struct gsm_network *dummy)
+{
+	cmd_init(1);
+	vty_init();
+
+	install_element(VIEW_NODE, &show_mgcp_cmd);
+
+
+	install_element(CONFIG_NODE, &cfg_mgcp_cmd);
+	install_node(&mgcp_node, config_write_mgcp);
+	install_default(MGCP_NODE);
+	install_element(MGCP_NODE, &cfg_mgcp_local_ip_cmd);
+	install_element(MGCP_NODE, &cfg_mgcp_bts_ip_cmd);
+	install_element(MGCP_NODE, &cfg_mgcp_bind_ip_cmd);
+	install_element(MGCP_NODE, &cfg_mgcp_bind_port_cmd);
+	install_element(MGCP_NODE, &cfg_mgcp_bind_early_cmd);
+	install_element(MGCP_NODE, &cfg_mgcp_rtp_base_port_cmd);
+	install_element(MGCP_NODE, &cfg_mgcp_sdp_payload_number_cmd);
+	install_element(MGCP_NODE, &cfg_mgcp_sdp_payload_name_cmd);
+	install_element(MGCP_NODE, &cfg_mgcp_loop_cmd);
+	install_element(MGCP_NODE, &cfg_mgcp_number_endp_cmd);
+	install_element(MGCP_NODE, &cfg_mgcp_forward_ip_cmd);
+	install_element(MGCP_NODE, &cfg_mgcp_forward_port_cmd);
+	return 0;
+}
+
+int main(int argc, char** argv)
+{
+	struct gsm_network dummy_network;
+	struct sockaddr_in addr;
+	int on = 1, i, rc;
+	struct debug_target *stderr_target;
+
+	tall_bsc_ctx = talloc_named_const(NULL, 1, "mgcp-callagent");
+
+	debug_init();
+	stderr_target = debug_target_create_stderr();
+	debug_add_target(stderr_target);
+	debug_set_all_filter(stderr_target, 1);
+
+	handle_options(argc, argv);
+
+	telnet_init(&dummy_network, 4243);
+	rc = vty_read_config_file(config_file);
+	if (rc < 0) {
+		fprintf(stderr, "Failed to parse the config file: '%s'\n", config_file);
+		return rc;
+	}
+
+
+	if (!bts_ip)
+		fprintf(stderr, "No BTS ip address specified. This will allow everyone to connect.\n");
+
+	endpoints = _talloc_zero_array(tall_bsc_ctx,
+				       sizeof(struct mgcp_endpoint),
+				       number_endpoints, "endpoints");
+	if (!endpoints) {
+		fprintf(stderr, "Failed to allocate endpoints: %d. Quitting.\n", number_endpoints);
+		return -1;
+	}
+
+	/* Initialize all endpoints */
+	for (i = 0; i < number_endpoints; ++i) {
+		endpoints[i].local_rtp.fd = -1;
+		endpoints[i].local_rtcp.fd = -1;
+		endpoints[i].ci = CI_UNUSED;
+	}
+
+	/*
+	 * This application supports two modes.
+         *    1.) a true MGCP gateway with support for AUEP, CRCX, MDCX, DLCX
+         *    2.) plain forwarding of RTP packets on the endpoints.
+	 * both modes are mutual exclusive
+	 */
+	if (forward_ip) {
+		int port = rtp_base_port;
+		if (forward_port != 0)
+			port = forward_port;
+
+		if (!early_bind) {
+			DEBUGP(DMGCP, "Forwarding requires early bind.\n");
+			return -1;
+		}
+
+		/*
+		 * Store the forward IP and assign a ci. For early bind
+		 * the sockets will be created after this.
+		 */
+		for (i = 1; i < number_endpoints; ++i) {
+			struct mgcp_endpoint *endp = &endpoints[i];
+			inet_aton(forward_ip, &endp->remote);
+			endp->ci = CI_UNUSED + 23;
+			endp->net_rtp = htons(rtp_calculate_port(ENDPOINT_NUMBER(endp), port));
+			endp->net_rtcp = htons(rtp_calculate_port(ENDPOINT_NUMBER(endp), port) + 1);
+		}
+
+		DEBUGP(DMGCP, "Configured for Audio Forwarding.\n");
+	} else {
+		bfd.when = BSC_FD_READ;
+		bfd.cb = read_call_agent;
+		bfd.fd = socket(AF_INET, SOCK_DGRAM, 0);
+		if (bfd.fd < 0) {
+			perror("Gateway failed to listen");
+			return -1;
+		}
+
+		setsockopt(bfd.fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
+
+		memset(&addr, 0, sizeof(addr));
+		addr.sin_family = AF_INET;
+		addr.sin_port = htons(source_port);
+		inet_aton(source_addr, &addr.sin_addr);
+
+		if (bind(bfd.fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
+			perror("Gateway failed to bind");
+			return -1;
+		}
+
+		bfd.data = msgb_alloc(4096, "mgcp-msg");
+		if (!bfd.data) {
+			fprintf(stderr, "Gateway memory error.\n");
+			return -1;
+		}
+
+
+		if (bsc_register_fd(&bfd) != 0) {
+			DEBUGP(DMGCP, "Failed to register the fd\n");
+			return -1;
+		}
+
+		DEBUGP(DMGCP, "Configured for MGCP.\n");
+	}
+
+	/* initialisation */
+	srand(time(NULL));
+
+	/* early bind */
+	if (early_bind) {
+		for (i = 1; i < number_endpoints; ++i) {
+			struct mgcp_endpoint *endp = &endpoints[i];
+			endp->rtp_port = rtp_calculate_port(ENDPOINT_NUMBER(endp), rtp_base_port);
+			if (bind_rtp(endp) != 0)
+				return -1;
+		}
+	}
+
+	/* main loop */
+	while (1) {
+		bsc_select_main(0);
+	}
+
+
+	return 0;
+}