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

jenkins.sh: build from libosmo-sccp and osmo-iuh master branches now for new
M3UA SIGTRAN.

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

1 files changed, 81 insertions, 14 deletions

diff --git a/src/libmgcp/mgcpgw_client.c b/src/libmgcp/mgcpgw_client.c
index 9f0c84de2..1910a9f35 100644
--- a/src/libmgcp/mgcpgw_client.c
+++ b/src/libmgcp/mgcpgw_client.c
@@ -35,15 +35,6 @@
 #include <unistd.h>
 #include <string.h>
 
-struct mgcpgw_client {
-	struct mgcpgw_client_conf actual;
-	uint32_t remote_addr;
-	struct osmo_wqueue wq;
-	mgcp_trans_id_t next_trans_id;
-	uint16_t next_endpoint;
-	struct llist_head responses_pending;
-};
-
 void mgcpgw_client_conf_init(struct mgcpgw_client_conf *conf)
 {
 	/* NULL and -1 default to MGCPGW_CLIENT_*_DEFAULT values */
@@ -52,12 +43,68 @@ void mgcpgw_client_conf_init(struct mgcpgw_client_conf *conf)
 		.local_port = -1,
 		.remote_addr = NULL,
 		.remote_port = -1,
+		.first_endpoint = 0,
+		.last_endpoint = 0,
+		.bts_base = 0,
 	};
 }
 
-unsigned int mgcpgw_client_next_endpoint(struct mgcpgw_client *client)
+/* Test if a given endpoint id is currently in use */
+static bool endpoint_in_use(uint16_t id, struct mgcpgw_client *client)
 {
-	return client->next_endpoint ++;
+	struct mgcp_inuse_endpoint *endpoint;
+	llist_for_each_entry(endpoint, &client->inuse_endpoints, entry) {
+		if (endpoint->id == id)
+			return true;
+	}
+
+	return false;
+}
+
+/* Find and seize an unsused endpoint id */
+int mgcpgw_client_next_endpoint(struct mgcpgw_client *client)
+{
+	int i;
+	uint16_t first_endpoint = client->actual.first_endpoint;
+	uint16_t last_endpoint = client->actual.last_endpoint;
+	struct mgcp_inuse_endpoint *endpoint;
+
+	/* Use the maximum permitted range if the VTY
+	 * configuration does not specify a range */
+	if (client->actual.last_endpoint == 0) {
+		first_endpoint = 1;
+		last_endpoint = 65534;
+	}
+
+	/* Test the permitted endpoint range for an endpoint
+	 * number that is not in use. When a suitable endpoint
+	 * number can be found, seize it by adding it to the
+	 * inuse list. */
+	for (i=first_endpoint;i<last_endpoint;i++)
+	{
+		if (endpoint_in_use(i,client) == false) {
+			endpoint = talloc_zero(client, struct mgcp_inuse_endpoint);
+			endpoint->id = i;
+			llist_add_tail(&endpoint->entry, &client->inuse_endpoints);
+			return endpoint->id;
+		}
+	}
+
+	/* All endpoints are busy! */
+	return -EINVAL;
+}
+
+/* Release a seized endpoint id to make it available again for other calls */
+void mgcpgw_client_release_endpoint(uint16_t id, struct mgcpgw_client *client)
+{
+	struct mgcp_inuse_endpoint *endpoint;
+	struct mgcp_inuse_endpoint *endpoint_tmp;
+	llist_for_each_entry_safe(endpoint, endpoint_tmp, &client->inuse_endpoints, entry) {
+		if (endpoint->id == id) {
+			llist_del(&endpoint->entry);
+			talloc_free(endpoint);
+		}
+	}
 }
 
 static void mgcpgw_client_handle_response(struct mgcpgw_client *mgcp,
@@ -257,9 +304,16 @@ static int mgcp_do_write(struct osmo_fd *fd, struct msgb *msg)
 {
 	int ret;
 	static char strbuf[4096];
-	unsigned int l = msg->len < sizeof(strbuf)-1 ? msg->len : sizeof(strbuf)-1;
+	unsigned int l = msg->len < sizeof(strbuf) ? msg->len : sizeof(strbuf);
+	unsigned int i;
+
 	strncpy(strbuf, (const char*)msg->data, l);
-	strbuf[l] = '\0';
+	for (i = 0; i < sizeof(strbuf); i++) {
+		if (strbuf[i] == '\n' || strbuf[i] == '\r') {
+			strbuf[i] = '\0';
+			break;
+		}
+	}
 	DEBUGP(DMGCP, "Tx MGCP msg to MGCP GW: '%s'\n", strbuf);
 
 	LOGP(DMGCP, LOGL_DEBUG, "Sending msg to MGCP GW size: %u\n", msg->len);
@@ -280,9 +334,9 @@ struct mgcpgw_client *mgcpgw_client_init(void *ctx,
 	mgcp = talloc_zero(ctx, struct mgcpgw_client);
 
 	INIT_LLIST_HEAD(&mgcp->responses_pending);
+	INIT_LLIST_HEAD(&mgcp->inuse_endpoints);
 
 	mgcp->next_trans_id = 1;
-	mgcp->next_endpoint = 1;
 
 	mgcp->actual.local_addr = conf->local_addr ? conf->local_addr :
 		MGCPGW_CLIENT_LOCAL_ADDR_DEFAULT;
@@ -294,6 +348,10 @@ struct mgcpgw_client *mgcpgw_client_init(void *ctx,
 	mgcp->actual.remote_port = conf->remote_port >= 0 ? (uint16_t)conf->remote_port :
 		MGCPGW_CLIENT_REMOTE_PORT_DEFAULT;
 
+	mgcp->actual.first_endpoint = conf->first_endpoint > 0 ? (uint16_t)conf->first_endpoint : 0;
+	mgcp->actual.last_endpoint = conf->last_endpoint > 0 ? (uint16_t)conf->last_endpoint : 0;
+	mgcp->actual.bts_base = conf->bts_base > 0 ? (uint16_t)conf->bts_base : 4000;
+
 	return mgcp;
 }
 
@@ -547,3 +605,12 @@ struct msgb *mgcp_msg_mdcx(struct mgcpgw_client *mgcp,
 		 rtp_conn_addr,
 		 rtp_port);
 }
+
+struct msgb *mgcp_msg_dlcx(struct mgcpgw_client *mgcp, uint16_t rtp_endpoint,
+			   unsigned int call_id)
+{
+	mgcp_trans_id_t trans_id = mgcpgw_client_next_trans_id(mgcp);
+	return mgcp_msg_from_str(trans_id,
+				 "DLCX %u %x@mgw MGCP 1.0\r\n"
+				 "C: %x\r\n", trans_id, rtp_endpoint, call_id);
+}