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
diff --git a/include/osmocom/bsc/osmo_bsc_mgcp.h b/include/osmocom/bsc/osmo_bsc_mgcp.h
new file mode 100644
index 0000000..ddcba0f
--- /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);