Public release of the cellmgr_ng code to convert E1 to IPA SCCP

1 files changed, 300 insertions, 0 deletions

diff --git a/src/mgcp/mgcp_network.c b/src/mgcp/mgcp_network.c
new file mode 100644
index 0000000..fbbfbf2
--- /dev/null
+++ b/src/mgcp/mgcp_network.c
@@ -0,0 +1,300 @@
+/* A Media Gateway Control Protocol Media Gateway: RFC 3435 */
+/* The protocol implementation */
+
+/*
+ * (C) 2009-2010 by Holger Hans Peter Freyther <zecke@selfish.org>
+ * (C) 2009-2010 by On-Waves
+ * 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 <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <endian.h>
+#include <errno.h>
+
+#include <sys/socket.h>
+#include <arpa/inet.h>
+
+#include <mgcp/mgcp.h>
+#include <mgcp/mgcp_internal.h>
+
+#include <laf0rge1/debug.h>
+#include <laf0rge1/msgb.h>
+#include <laf0rge1/talloc.h>
+#include <laf0rge1/select.h>
+
+#warning "Make use of the rtp proxy code"
+
+/* according to rtp_proxy.c RFC 3550 */
+struct rtp_hdr {
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+	u_int8_t  csrc_count:4,
+		  extension:1,
+		  padding:1,
+		  version:2;
+	u_int8_t  payload_type:7,
+		  marker:1;
+#elif __BYTE_ORDER == __BIG_ENDIAN
+	u_int8_t  version:2,
+		  padding:1,
+		  extension:1,
+		  csrc_count:4;
+	u_int8_t  marker:1,
+		  payload_type:7;
+#endif
+	u_int16_t sequence;
+	u_int32_t timestamp;
+	u_int32_t ssrc;
+} __attribute__((packed));
+
+
+enum {
+	DEST_NETWORK = 0,
+	DEST_BTS = 1,
+};
+
+enum {
+	PROTO_RTP,
+	PROTO_RTCP,
+};
+
+#define DUMMY_LOAD 0x23
+
+
+static int udp_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));
+}
+
+int mgcp_send_dummy(struct mgcp_endpoint *endp)
+{
+	static char buf[] = { DUMMY_LOAD };
+
+	return udp_send(endp->local_rtp.fd, &endp->remote,
+			endp->net_rtp, buf, 1);
+}
+
+static void patch_payload(int payload, char *data, int len)
+{
+	struct rtp_hdr *rtp_hdr;
+
+	if (len < sizeof(*rtp_hdr))
+		return;
+
+	if (payload < 0)
+		return;
+
+	rtp_hdr = (struct rtp_hdr *) data;
+	rtp_hdr->payload_type = payload;
+}
+
+/*
+ * 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;
+	struct mgcp_config *cfg;
+	int rc, dest, proto;
+
+	endp = (struct mgcp_endpoint *) fd->data;
+	cfg = endp->cfg;
+
+	rc = recvfrom(fd->fd, &buf, sizeof(buf), 0,
+			    (struct sockaddr *) &addr, &slen);
+	if (rc < 0) {
+		LOGP(DMGCP, LOGL_ERROR, "Failed to receive message on: 0x%x errno: %d/%s\n",
+			ENDPOINT_NUMBER(endp), errno, strerror(errno));
+		return -1;
+	}
+
+	/* do not forward aynthing... maybe there is a packet from the bts */
+	if (endp->ci == CI_UNUSED) {
+		LOGP(DMGCP, LOGL_DEBUG, "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 || cfg->forward_ip)) {
+		/* it was the BTS... */
+		if (!cfg->bts_ip
+		    || memcmp(&addr.sin_addr, &cfg->bts_in, sizeof(cfg->bts_in)) == 0
+		    || memcmp(&addr.sin_addr, &endp->bts, sizeof(endp->bts)) == 0) {
+			if (fd == &endp->local_rtp) {
+				endp->bts_rtp = addr.sin_port;
+			} else {
+				endp->bts_rtcp = addr.sin_port;
+			}
+
+			endp->bts = addr.sin_addr;
+			LOGP(DMGCP, LOGL_NOTICE, "Found BTS for endpoint: 0x%x on port: %d/%d of %s\n",
+				ENDPOINT_NUMBER(endp), ntohs(endp->bts_rtp), ntohs(endp->bts_rtcp),
+				inet_ntoa(addr.sin_addr));
+
+		}
+	}
+
+	/* throw away the dummy message */
+	if (rc == 1 && buf[0] == DUMMY_LOAD) {
+		LOGP(DMGCP, LOGL_NOTICE, "Filtered dummy on 0x%x\n",
+			ENDPOINT_NUMBER(endp));
+		return 0;
+	}
+
+	/* do this before the loop handling */
+	if (dest == DEST_NETWORK)
+		++endp->in_bts;
+	else
+		++endp->in_remote;
+
+	/* For loop toggle the destination and then dispatch. */
+	if (cfg->audio_loop)
+		dest = !dest;
+
+	if (dest == DEST_NETWORK) {
+		if (proto == PROTO_RTP)
+			patch_payload(endp->net_payload_type, buf, rc);
+		return udp_send(fd->fd, &endp->remote,
+			     proto == PROTO_RTP ? endp->net_rtp : endp->net_rtcp,
+			     buf, rc);
+	} else {
+		if (proto == PROTO_RTP)
+			patch_payload(endp->bts_payload_type, buf, rc);
+		return udp_send(fd->fd, &endp->bts,
+			     proto == PROTO_RTP ? endp->bts_rtp : endp->bts_rtcp,
+			     buf, rc);
+	}
+}
+
+static int create_bind(const char *source_addr, 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) {
+		LOGP(DMGCP, LOGL_ERROR, "Failed to create UDP port.\n");
+		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 set_ip_tos(int fd, int tos)
+{
+	int ret;
+	ret = setsockopt(fd, IPPROTO_IP, IP_TOS,
+			 &tos, sizeof(tos));
+	return ret != 0;
+}
+
+static int bind_rtp(struct mgcp_endpoint *endp)
+{
+	struct mgcp_config *cfg = endp->cfg;
+
+	if (create_bind(cfg->source_addr, &endp->local_rtp, endp->rtp_port) != 0) {
+		LOGP(DMGCP, LOGL_ERROR, "Failed to create RTP port: %s:%d on 0x%x\n",
+		       cfg->source_addr, endp->rtp_port, ENDPOINT_NUMBER(endp));
+		goto cleanup0;
+	}
+
+	if (create_bind(cfg->source_addr, &endp->local_rtcp, endp->rtp_port + 1) != 0) {
+		LOGP(DMGCP, LOGL_ERROR, "Failed to create RTCP port: %s:%d on 0x%x\n",
+		       cfg->source_addr, endp->rtp_port + 1, ENDPOINT_NUMBER(endp));
+		goto cleanup1;
+	}
+
+	set_ip_tos(endp->local_rtp.fd, cfg->endp_dscp);
+	set_ip_tos(endp->local_rtcp.fd, cfg->endp_dscp);
+
+	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) {
+		LOGP(DMGCP, LOGL_ERROR, "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) {
+		LOGP(DMGCP, LOGL_ERROR, "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;
+}
+
+int mgcp_bind_rtp_port(struct mgcp_endpoint *endp, int rtp_port)
+{
+	endp->rtp_port = rtp_port;
+	return bind_rtp(endp);
+}