mgcp: use osmo-mgw to switch RTP streams

osmo-bsc currently negotiates the RTP stream directly with the
BTS and reports back the RTP IP/Port on the BTS. This works fine
for a single BTS, but for Handover the port/ip pointing to the
MSC side must not change, so an entity in between the BTSs and
the MSC is required.

Integrate the mgcp-client and use osmo-mgw to switch the RTP
streams.

Depends: osmo-mgw Ib5fcc72775bf72b489ff79ade36fb345d8d20736
Depends: osmo-mgw I44b338b09de45e1675cedf9737fa72dde72e979a
Depends: osmo-mgw I29c5e2fb972896faeb771ba040f015592487fcbe

Change-Id: Ia2882b7ca31a3219c676986e85045fa08a425d7a

4 files changed, 70 insertions, 0 deletions

diff --git a/include/osmocom/bsc/Makefile.am b/include/osmocom/bsc/Makefile.am
index 8ad2b5d2e..1f7cd39b7 100644
--- a/include/osmocom/bsc/Makefile.am
+++ b/include/osmocom/bsc/Makefile.am
@@ -41,6 +41,7 @@ noinst_HEADERS = \
 	openbscdefines.h \
 	osmo_bsc.h \
 	osmo_bsc_grace.h \
+	osmo_bsc_mgcp.h \
 	osmo_bsc_rf.h \
 	osmo_bsc_sigtran.h \
 	bsc_msc_data.h \
diff --git a/include/osmocom/bsc/gsm_data.h b/include/osmocom/bsc/gsm_data.h
index 74298b847..b9427b8cb 100644
--- a/include/osmocom/bsc/gsm_data.h
+++ b/include/osmocom/bsc/gsm_data.h
@@ -479,6 +479,11 @@ struct gsm_network {
 	uint8_t t3212;
 
 	struct {
+		struct mgcp_client_conf *conf;
+		struct mgcp_client *client;
+	} mgw;
+
+	struct {
 		/* CS7 instance id number (set via VTY) */
 		uint32_t cs7_instance;
 		/* A list with the context information about
diff --git a/include/osmocom/bsc/osmo_bsc.h b/include/osmocom/bsc/osmo_bsc.h
index 5ebea5079..8a5cd3067 100644
--- a/include/osmocom/bsc/osmo_bsc.h
+++ b/include/osmocom/bsc/osmo_bsc.h
@@ -29,6 +29,20 @@ struct osmo_bsc_sccp_con {
 	uint32_t rtp_ip;
 	int rtp_port;
 
+	/* RTP address of the remote end (assigned by MSC through assignment
+	 * request) */
+	struct sockaddr_storage aoip_rtp_addr_remote;
+
+	/* Local RTP address (reported back to the MSC by us with the
+	 * assignment complete message) */
+	struct sockaddr_storage aoip_rtp_addr_local;
+
+	/* storage to keep states of the MGCP connection handler, the
+	 * handler is created when an assignment request is received
+	 * and is terminated when the assignment complete message is
+	 * sent */
+	struct mgcp_ctx *mgcp_ctx;
+
 	/* for advanced ping/pong */
 	int send_ping;
 
@@ -72,4 +86,6 @@ void bsc_gen_location_state_trap(struct gsm_bts *bts);
 
 struct llist_head *bsc_access_lists(void);
 
+int bssmap_send_aoip_ass_compl(struct gsm_lchan *lchan);
+
 #endif
diff --git a/include/osmocom/bsc/osmo_bsc_mgcp.h b/include/osmocom/bsc/osmo_bsc_mgcp.h
new file mode 100644
index 000000000..ddcba0f49
--- /dev/null
+++ b/include/osmocom/bsc/osmo_bsc_mgcp.h
@@ -0,0 +1,48 @@
+/* (C) 2017 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
+ * All Rights Reserved
+ *
+ * Author: Philipp Maier
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation; either version 3 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#pragma once
+
+/* MGCP state handler context (fsm etc..) */
+struct mgcp_ctx {
+	/* FSM instance, which handles the connection switching procedure */
+	struct osmo_fsm_inst *fsm;
+
+	/* RTP endpoint number */
+	uint16_t rtp_endpoint;
+
+	/* Copy of the pointer and the data with context information
+	 * needed to process the AoIP and MGCP requests (system data) */
+	struct mgcp_client *mgcp;
+
+	struct osmo_bsc_sccp_con *conn;
+	enum gsm48_chan_mode chan_mode;
+	bool full_rate;
+	struct gsm_lchan *lchan;
+	struct gsm_lchan *ho_lchan;
+	struct msgb *resp;
+};
+
+struct mgcp_ctx *mgcp_assignm_req(void *ctx, struct mgcp_client *mgcp, struct osmo_bsc_sccp_con *conn,
+				  enum gsm48_chan_mode chan_mode, bool full_rate);
+void mgcp_clear_complete(struct mgcp_ctx *mgcp_ctx, struct msgb *resp);
+void mgcp_ass_complete(struct mgcp_ctx *mgcp_ctx, struct gsm_lchan *lchan);
+void mgcp_handover(struct mgcp_ctx *mgcp_ctx, struct gsm_lchan *ho_lchan);
+void mgcp_free_ctx(struct mgcp_ctx *mgcp_ctx);