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, 1 insertions, 1 deletions

diff --git a/openbsc/src/nat/bsc_nat_utils.c b/openbsc/src/nat/bsc_nat_utils.c
index d9fceaf8f..1e51737f1 100644
--- a/openbsc/src/nat/bsc_nat_utils.c
+++ b/openbsc/src/nat/bsc_nat_utils.c
@@ -100,7 +100,7 @@ void sccp_connection_destroy(struct sccp_connections *conn)
 	LOGP(DNAT, LOGL_DEBUG, "Destroy 0x%x <-> 0x%x mapping for con %p\n",
 	     sccp_src_ref_to_int(&conn->real_ref),
 	     sccp_src_ref_to_int(&conn->patched_ref), conn->bsc);
-	bsc_mgcp_clear(conn);
+	bsc_mgcp_dlcx(conn);
 	llist_del(&conn->list_entry);
 	talloc_free(conn);
 }