a_iface: fix missing clear command

When a subscriber connection is freed on the MSC side (the
conversion is over) the MSC should send a clear command to
the BSC in order to inform the BSC that the connection is
over. Currently this step is missing. Instead we wait for
the BSC to issue a clear request. This is not as it should
be, connections should be actively cleared by the MSC.

Add the missing clear command

3 files changed, 16 insertions, 0 deletions

diff --git a/openbsc/include/openbsc/a_iface.h b/openbsc/include/openbsc/a_iface.h
index 4c51a7f4a..149f1c71e 100644
--- a/openbsc/include/openbsc/a_iface.h
+++ b/openbsc/include/openbsc/a_iface.h
@@ -64,6 +64,9 @@ int a_iface_tx_paging(const char *imsi, uint32_t tmsi, uint16_t lac);
 /* Send assignment request via A-interface */
 int a_iface_tx_assignment(const struct gsm_trans *trans);
 
+/* Send clear command via A-interface */
+int a_iface_tx_clear_cmd(struct gsm_subscriber_connection *conn);
+
 /* Clear all subscriber connections on a specified BSC
  * (Helper function for a_iface_bssap.c) */
 void a_clear_all(struct osmo_sccp_user *scu, const struct osmo_sccp_addr *bsc_addr);
diff --git a/openbsc/src/libmsc/a_iface.c b/openbsc/src/libmsc/a_iface.c
index 2a28803dd..b16936f50 100644
--- a/openbsc/src/libmsc/a_iface.c
+++ b/openbsc/src/libmsc/a_iface.c
@@ -405,6 +405,17 @@ int a_iface_tx_assignment(const struct gsm_trans *trans)
 	return osmo_sccp_tx_data_msg(conn->a.scu, conn->a.conn_id, msg);
 }
 
+/* Send clear command via A-interface */
+int a_iface_tx_clear_cmd(struct gsm_subscriber_connection *conn)
+{
+	struct msgb *msg;
+
+	LOGP(DMSC, LOGL_NOTICE, "Sendig clear command to BSC (conn_id=%u)\n", conn->a.conn_id);
+
+	msg = gsm0808_create_clear_command(GSM0808_CAUSE_CALL_CONTROL);
+	return osmo_sccp_tx_data_msg(conn->a.scu, conn->a.conn_id, msg);
+}
+
 /* Callback function: Close all open connections */
 static void a_reset_cb(const void *priv)
 {
diff --git a/openbsc/src/libmsc/osmo_msc.c b/openbsc/src/libmsc/osmo_msc.c
index b9607e3ec..dc62f2fc9 100644
--- a/openbsc/src/libmsc/osmo_msc.c
+++ b/openbsc/src/libmsc/osmo_msc.c
@@ -29,6 +29,7 @@
 #include <openbsc/vlr.h>
 #include <openbsc/osmo_msc.h>
 #include <openbsc/iu.h>
+#include <openbsc/a_iface.h>
 
 #include <openbsc/gsm_04_11.h>
 
@@ -207,6 +208,7 @@ void msc_subscr_con_cleanup(struct gsm_subscriber_connection *conn)
 		return;
 
 	if (conn->vsub) {
+		a_iface_tx_clear_cmd(conn);
 		DEBUGP(DRLL, "subscr %s: Freeing subscriber connection\n",
 		       vlr_subscr_name(conn->vsub));
 		msc_subscr_cleanup(conn->vsub);