nat: Allocate the endpoint status dynamically

Allocate the status for an endpoint dynamically. We will support
BSCs with different amount of multiplexes and need to have this
flexibility in the future. Add the proper null checks to the
current users of this code.

openbsc/include/openbsc/bsc_nat.h

@@ -78,7 +78,7 @@ struct bsc_connection {
 	struct timer_list pong_timeout;
 
 	/* mgcp related code */
-	int endpoint_status[32];
+	char *_endpoint_status;
 	int last_endpoint;
 
 	/* a back pointer */
@@ -124,6 +124,9 @@ struct bsc_config {
 
 	int forbid_paging;
 
+	/* audio handling */
+	int number_multiplexes;
+
 	/* backpointer */
 	struct bsc_nat *nat;
 

openbsc/src/nat/bsc_mgcp_utils.c

@@ -38,18 +38,33 @@
 #include <errno.h>
 #include <unistd.h>
 
+static int bsc_init_endps_if_needed(struct bsc_connection *con)
+{
+	/* we have done that */
+	if (con->_endpoint_status)
+		return 0;
+
+	/* we have no config... */
+	if (!con->cfg)
+		return -1;
+
+	con->_endpoint_status = talloc_zero_array(con, char,
+						  (32 * con->cfg->number_multiplexes) + 1);
+	return con->_endpoint_status == NULL;
+}
+
 static int bsc_assign_endpoint(struct bsc_connection *bsc, struct sccp_connections *con)
 {
-	const int number_endpoints = ARRAY_SIZE(bsc->endpoint_status);
+	const int number_endpoints = 31 * bsc->cfg->number_multiplexes;
 	int i;
 
-	for (i = 1; i < number_endpoints; ++i) {
+	for (i = 1; i <= number_endpoints; ++i) {
 		int endpoint = (bsc->last_endpoint + i) % number_endpoints;
 		if (endpoint == 0)
 			endpoint = 1;
 
-		if (bsc->endpoint_status[endpoint] == 0) {
-			bsc->endpoint_status[endpoint] = 1;
+		if (bsc->_endpoint_status[endpoint] == 0) {
+			bsc->_endpoint_status[endpoint] = 1;
 			con->bsc_endp = endpoint;
 			bsc->last_endpoint = endpoint;
 			return 0;
@@ -119,6 +134,8 @@ int bsc_mgcp_assign_patch(struct sccp_connections *con, struct msgb *msg)
 	}
 
 	con->msc_endp = endp;
+	if (bsc_init_endps_if_needed(con->bsc) != 0)
+		return -1;
 	if (bsc_assign_endpoint(con->bsc, con) != 0)
 		return -1;
 
@@ -202,10 +219,10 @@ void bsc_mgcp_init(struct sccp_connections *con)
 void bsc_mgcp_dlcx(struct sccp_connections *con)
 {
 	/* send a DLCX down the stream */
-	if (con->bsc_endp != -1) {
-		if (con->bsc->endpoint_status[con->bsc_endp] != 1)
+	if (con->bsc_endp != -1 && con->bsc->_endpoint_status) {
+		if (con->bsc->_endpoint_status[con->bsc_endp] != 1)
 			LOGP(DNAT, LOGL_ERROR, "Endpoint 0x%x was not in use\n", con->bsc_endp);
-		con->bsc->endpoint_status[con->bsc_endp] = 0;
+		con->bsc->_endpoint_status[con->bsc_endp] = 0;
 		bsc_mgcp_send_dlcx(con->bsc, con->bsc_endp);
 		bsc_mgcp_free_endpoint(con->bsc->nat, con->msc_endp);
 	}

openbsc/src/nat/bsc_nat_utils.c

@@ -126,6 +126,7 @@ struct bsc_config *bsc_config_alloc(struct bsc_nat *nat, const char *token)
 	conf->token = talloc_strdup(conf, token);
 	conf->nr = nat->num_bsc;
 	conf->nat = nat;
+	conf->number_multiplexes = 1;
 
 	INIT_LLIST_HEAD(&conf->lac_list);
 

openbsc/src/nat/bsc_nat_vty.c

@@ -172,15 +172,21 @@ DEFUN(show_bsc_mgcp, show_bsc_mgcp_cmd, "show bsc mgcp NR",
 	int i;
 
 	llist_for_each_entry(con, &_nat->bsc_connections, list_entry) {
+		int endpoints;
 		if (!con->cfg)
 			continue;
 		if (con->cfg->nr != nr)
 			continue;
 
+		/* this bsc has no audio endpoints yet */
+		if (!con->_endpoint_status)
+			continue;
+
 		vty_out(vty, "MGCP Status for %d%s", con->cfg->nr, VTY_NEWLINE);
-		for (i = 1; i < ARRAY_SIZE(con->endpoint_status); ++i)
+		endpoints = 31 * con->cfg->number_multiplexes;
+		for (i = 1; i <= endpoints; ++i)
 			vty_out(vty, " Endpoint 0x%x %s%s", i,
-				con->endpoint_status[i] == 0 ? "free" : "allocated",
+				con->_endpoint_status[i] == 0 ? "free" : "allocated",
 				VTY_NEWLINE);
 		break;
 	}

openbsc/tests/bsc-nat/bsc_nat_test.c

@@ -479,7 +479,7 @@ static void test_mgcp_ass_tracking(void)
 		fprintf(stderr, "Assigned timeslot should have been 1.\n");
 		abort();
 	}
-	if (con.bsc->endpoint_status[0x1b] != 1) {
+	if (con.bsc->_endpoint_status[0x1b] != 1) {
 		fprintf(stderr, "The status on the BSC is wrong.\n");
 		abort();
 	}
@@ -498,7 +498,7 @@ static void test_mgcp_ass_tracking(void)
 
 	bsc_mgcp_dlcx(&con);
 	if (con.bsc_endp != -1 || con.msc_endp != -1 ||
-	    con.bsc->endpoint_status[1] != 0 || con.bsc->last_endpoint != 0x1b) {
+	    con.bsc->_endpoint_status[1] != 0 || con.bsc->last_endpoint != 0x1b) {
 		fprintf(stderr, "Clearing should remove the mapping.\n");
 		abort();
 	}