nat: Make the code work in terms of endpoints instead of timeslot/multiplex

We are going to have more than one trunk, so all code hardcoding the
multiplex to zero must go. Avoid this kind of problem by saving the
MGCP endpoint number and comparing that.

openbsc/include/openbsc/bsc_nat_sccp.h

@@ -79,10 +79,13 @@ struct sccp_connections {
 	int con_type;
 	int con_local;
 
-	/* GSM audio handling. That is 32 * multiplex + ts */
+	/*
+	 * audio handling. Remember if we have ever send a CRCX,
+	 * remember the endpoint used by the MSC and BSC.
+	 */
 	int crcx;
-	int msc_timeslot;
-	int bsc_timeslot;
+	int msc_endp;
+	int bsc_endp;
 
 	/* timeout handling */
 	struct timespec creation_time;

openbsc/src/nat/bsc_mgcp_utils.c

@@ -45,7 +45,7 @@ int bsc_mgcp_assign(struct sccp_connections *con, struct msgb *msg)
 	uint16_t cic;
 	uint8_t timeslot;
 	uint8_t multiplex;
-	int combined;
+	int endp;
 
 	if (!msg->l3h) {
 		LOGP(DNAT, LOGL_ERROR, "Assignment message should have l3h pointer.\n");
@@ -68,22 +68,22 @@ int bsc_mgcp_assign(struct sccp_connections *con, struct msgb *msg)
 	multiplex = (cic & ~0x1f) >> 5;
 
 
-	combined = (32 * multiplex) + timeslot;
+	endp = mgcp_timeslot_to_endpoint(multiplex, timeslot);
 
 	/* find stale connections using that endpoint */
 	llist_for_each_entry(mcon, &con->bsc->nat->sccp_connections, list_entry) {
-		if (mcon->msc_timeslot == combined) {
+		if (mcon->msc_endp == endp) {
 			LOGP(DNAT, LOGL_ERROR,
-			     "Timeslot %d was assigned to 0x%x and now 0x%x\n",
-			     combined,
+			     "Endpoint %d was assigned to 0x%x and now 0x%x\n",
+			     endp,
 			     sccp_src_ref_to_int(&mcon->patched_ref),
 			     sccp_src_ref_to_int(&con->patched_ref));
 			bsc_mgcp_dlcx(mcon);
 		}
 	}
 
-	con->msc_timeslot = combined;
-	con->bsc_timeslot = con->msc_timeslot;
+	con->msc_endp = endp;
+	con->bsc_endp = endp;
 	return 0;
 }
 
@@ -147,19 +147,17 @@ static void bsc_mgcp_send_dlcx(struct bsc_connection *bsc, int endpoint)
 
 void bsc_mgcp_init(struct sccp_connections *con)
 {
-	con->msc_timeslot = -1;
-	con->bsc_timeslot = -1;
+	con->msc_endp = -1;
+	con->bsc_endp = -1;
 	con->crcx = 0;
 }
 
 void bsc_mgcp_dlcx(struct sccp_connections *con)
 {
 	/* send a DLCX down the stream */
-	if (con->bsc_timeslot != -1 && con->crcx) {
-		int bsc_endp = mgcp_timeslot_to_endpoint(0, con->bsc_timeslot);
-		int msc_endp = mgcp_timeslot_to_endpoint(0, con->msc_timeslot);
-		bsc_mgcp_send_dlcx(con->bsc, bsc_endp);
-		bsc_mgcp_free_endpoint(con->bsc->nat, msc_endp);
+	if (con->bsc_endp != -1 && con->crcx) {
+		bsc_mgcp_send_dlcx(con->bsc, con->bsc_endp);
+		bsc_mgcp_free_endpoint(con->bsc->nat, con->msc_endp);
 	}
 
 	bsc_mgcp_init(con);
@@ -172,9 +170,9 @@ struct sccp_connections *bsc_mgcp_find_con(struct bsc_nat *nat, int endpoint)
 	struct sccp_connections *sccp;
 
 	llist_for_each_entry(sccp, &nat->sccp_connections, list_entry) {
-		if (sccp->msc_timeslot == -1)
+		if (sccp->msc_endp == -1)
 			continue;
-		if (mgcp_timeslot_to_endpoint(0, sccp->msc_timeslot) != endpoint)
+		if (sccp->msc_endp != endpoint)
 			continue;
 
 		con = sccp;

openbsc/src/nat/bsc_nat_vty.c

@@ -121,7 +121,7 @@ DEFUN(show_sccp, show_sccp_cmd, "show sccp connections",
 			sccp_src_ref_to_int(&con->patched_ref),
 			con->has_remote_ref,
 			sccp_src_ref_to_int(&con->remote_ref),
-			con->msc_timeslot, con->bsc_timeslot,
+			con->msc_endp, con->bsc_endp,
 			bsc_con_type_to_string(con->con_type),
 			VTY_NEWLINE);
 	}

openbsc/tests/bsc-nat/bsc_nat_test.c

@@ -449,19 +449,19 @@ static void test_mgcp_ass_tracking(void)
 		abort();
 	}
 
-	if (con.msc_timeslot != 21) {
+	if (con.msc_endp != 21) {
 		fprintf(stderr, "Timeslot should be 21.\n");
 		abort();
 	}
 
-	if (con.bsc_timeslot != 21) {
+	if (con.bsc_endp != 21) {
 		fprintf(stderr, "Assigned timeslot should have been 21.\n");
 		abort();
 	}
 	talloc_free(parsed);
 
 	bsc_mgcp_dlcx(&con);
-	if (con.bsc_timeslot != -1 || con.msc_timeslot != -1) {
+	if (con.bsc_endp != -1 || con.msc_endp != -1) {
 		fprintf(stderr, "Clearing should remove the mapping.\n");
 		abort();
 	}
@@ -483,8 +483,8 @@ static void test_mgcp_find(void)
 	llist_add(&con->list_entry, &nat->bsc_connections);
 
 	sccp_con = talloc_zero(con, struct sccp_connections);
-	sccp_con->msc_timeslot = 12;
-	sccp_con->bsc_timeslot = 12;
+	sccp_con->msc_endp = 12;
+	sccp_con->bsc_endp = 12;
 	sccp_con->bsc = con;
 	llist_add(&sccp_con->list_entry, &nat->sccp_connections);
 
@@ -498,13 +498,6 @@ static void test_mgcp_find(void)
 		abort();
 	}
 
-	sccp_con->msc_timeslot = 0;
-	sccp_con->bsc_timeslot = 0;
-	if (bsc_mgcp_find_con(nat, 1) != sccp_con) {
-		fprintf(stderr, "Didn't find the connection\n");
-		abort();
-	}
-
 	/* free everything */
 	talloc_free(nat);
 }