Implement AoIP, port to M3UA SIGTRAN (large addition and refactoring)

This was originally a long series of commits converging to the final result
seen in this patch. It does not make much sense to review the smaller steps'
trial and error, we need to review this entire change as a whole.

Implement AoIP in osmo-msc and osmo-bsc.

Change over to the new libosmo-sigtran API with support for proper
SCCP/M3UA/SCTP stacking, as mandated by 3GPP specifications for the IuCS and
IuPS interfaces.

From here on, a separate osmo-stp process is required for SCCP routing between
OsmoBSC / OsmoHNBGW <-> OsmoMSC / OsmoSGSN

Patch-by: pmaier, nhofmeyr, laforge
Change-Id: I5ae4e05ee7c57cad341ea5e86af37c1f6b0ffa77

1 files changed, 30 insertions, 11 deletions

diff --git a/src/osmo-bsc/osmo_bsc_api.c b/src/osmo-bsc/osmo_bsc_api.c
index 8c33e2b57..f7343f743 100644
--- a/src/osmo-bsc/osmo_bsc_api.c
+++ b/src/osmo-bsc/osmo_bsc_api.c
@@ -27,6 +27,7 @@
 #include <osmocom/gsm/gsm0808.h>
 
 #include <osmocom/sccp/sccp.h>
+#include <openbsc/osmo_bsc_sigtran.h>
 
 #define return_when_not_connected(conn) \
 	if (!conn->sccp_con) {\
@@ -45,7 +46,7 @@
 		LOGP(DMSC, LOGL_ERROR, "Failed to allocate response.\n"); \
 		return; \
 	} \
-	bsc_queue_for_msc(conn->sccp_con, resp);
+	osmo_bsc_sigtran_send(conn->sccp_con, resp);
 
 static int bsc_clear_request(struct gsm_subscriber_connection *conn, uint32_t cause);
 static int complete_layer3(struct gsm_subscriber_connection *conn,
@@ -263,7 +264,8 @@ static int complete_layer3(struct gsm_subscriber_connection *conn,
 	}
 
 	/* allocate resource for a new connection */
-	ret = bsc_create_new_connection(conn, msc, send_ping);
+	//ret = bsc_create_new_connection(conn, msc, send_ping);
+	ret = osmo_bsc_sigtran_new_conn(conn, msc);
 
 	if (ret != BSC_CON_SUCCESS) {
 		/* allocation has failed */
@@ -292,13 +294,13 @@ static int complete_layer3(struct gsm_subscriber_connection *conn,
 	if (!resp) {
 		LOGP(DMSC, LOGL_DEBUG, "Failed to create layer3 message.\n");
 		sccp_connection_free(conn->sccp_con->sccp);
-		bsc_delete_connection(conn->sccp_con);
+		osmo_bsc_sigtran_del_conn(conn->sccp_con);
 		return BSC_API_CONN_POL_REJECT;
 	}
 
-	if (bsc_open_connection(conn->sccp_con, resp) != 0) {
+	if (osmo_bsc_sigtran_open_conn(conn->sccp_con, resp) != 0) {
 		sccp_connection_free(conn->sccp_con->sccp);
-		bsc_delete_connection(conn->sccp_con);
+		osmo_bsc_sigtran_del_conn(conn->sccp_con);
 		msgb_free(resp);
 		return BSC_API_CONN_POL_REJECT;
 	}
@@ -433,11 +435,28 @@ static void bsc_assign_compl(struct gsm_subscriber_connection *conn, uint8_t rr_
 	struct msgb *resp;
 	return_when_not_connected(conn);
 
-	LOGP(DMSC, LOGL_INFO, "Tx MSC ASSIGN COMPL\n");
-
-	resp = gsm0808_create_assignment_completed(rr_cause, chosen_channel,
-						   encr_alg_id, speech_model);
-	queue_msg_or_return(resp);
+	if (is_ipaccess_bts(conn->bts) && conn->sccp_con->rtp_ip) {
+		/* NOTE: In a network that makes use of an IPA base station
+		 * and AoIP, we have to wait until the BTS reports its RTP
+		 * IP/Port combination back to BSC via RSL. Unfortunately, the
+		 * IPA protocol sends its Abis assignment complete message
+		 * before it sends its RTP IP/Port via IPACC. So we will now
+		 * postpone the AoIP assignment completed message until we
+		 * know the RTP IP/Port combination. */
+		LOGP(DMSC, LOGL_INFO, "POSTPONE MSC ASSIGN COMPL\n");
+		conn->lchan->abis_ip.ass_compl.rr_cause = rr_cause;
+		conn->lchan->abis_ip.ass_compl.chosen_channel = chosen_channel;
+		conn->lchan->abis_ip.ass_compl.encr_alg_id = encr_alg_id;
+		conn->lchan->abis_ip.ass_compl.speech_mode = speech_model;
+		conn->lchan->abis_ip.ass_compl.valid = true;
+
+	} else {
+		/* NOTE: Send the A assignment complete message immediately. */
+		LOGP(DMSC, LOGL_INFO, "Tx MSC ASSIGN COMPL\n");
+		resp = gsm0808_create_assignment_completed(rr_cause, chosen_channel,
+							   encr_alg_id, speech_model);
+		queue_msg_or_return(resp);
+	}
 }
 
 static void bsc_assign_fail(struct gsm_subscriber_connection *conn,
@@ -474,7 +493,7 @@ static int bsc_clear_request(struct gsm_subscriber_connection *conn, uint32_t ca
 		return 1;
 	}
 
-	bsc_queue_for_msc(sccp, resp);
+	osmo_bsc_sigtran_send(sccp, resp);
 	return 1;
 }