nat: Change MGCP DLCX handling and send dummy MDCX to the BTS.

When setting a new MSC timeslot to a SCCP connection check if
any of the existing connections have this timeslot, if so we will
send a DLCX down the stream to make sure it is closed there, when
we will CRCX this new timeslot we will happily reallocate it.

When the SCCP connection goes away, or we get a DLCX from the
network, or the BSC is gone we will send a DLCX message down the
stream as well.

When we receive a CRCX from the network we will forward the CRCX
as usual and send a dummy MDCX after it.

For the DLCX and the dummy MDCX we send a custom MGCP message
that will not provoke an answer. Even if the downstream MGCP GW
will answer we will ignore it due the dummy transaction id that
is not used anywhere else.

This change should make sure that we close the dowstream endpoint
all the time, even when the DLCX arrives after the SCCP connection
is torndown.

1 files changed, 13 insertions, 1 deletions

diff --git a/openbsc/tests/bsc-nat/bsc_nat_test.c b/openbsc/tests/bsc-nat/bsc_nat_test.c
index 4666c3b23..8623123f7 100644
--- a/openbsc/tests/bsc-nat/bsc_nat_test.c
+++ b/openbsc/tests/bsc-nat/bsc_nat_test.c
@@ -395,6 +395,8 @@ static void test_paging(void)
 
 static void test_mgcp_ass_tracking(void)
 {
+	struct bsc_connection *bsc;
+	struct bsc_nat *nat;
 	struct sccp_connections con;
 	struct bsc_nat_parsed *parsed;
 	struct msgb *msg;
@@ -402,6 +404,14 @@ static void test_mgcp_ass_tracking(void)
 	fprintf(stderr, "Testing MGCP.\n");
 	memset(&con, 0, sizeof(con));
 
+	nat = bsc_nat_alloc();
+	nat->bsc_endpoints = talloc_zero_array(nat,
+					       struct bsc_endpoint,
+					       33);
+	bsc = bsc_connection_alloc(nat);
+	bsc->cfg = bsc_config_alloc(nat, "foo", 2323);
+	con.bsc = bsc;
+
 	msg = msgb_alloc(4096, "foo");
 	copy_to_msg(msg, ass_cmd, sizeof(ass_cmd));
 	parsed = bsc_nat_parse(msg);
@@ -421,11 +431,13 @@ static void test_mgcp_ass_tracking(void)
 	}
 	talloc_free(parsed);
 
-	bsc_mgcp_clear(&con);
+	bsc_mgcp_dlcx(&con);
 	if (con.bsc_timeslot != -1 || con.msc_timeslot != -1) {
 		fprintf(stderr, "Clearing should remove the mapping.\n");
 		abort();
 	}
+
+	talloc_free(nat);
 }
 
 /* test the code to find a given connection */