IuCS: send RANAP CommonID

Add libiu function to send a CommonID message down a UE connection,
iu_tx_common_id(); add also a corresponding stub to libiudummy for linking with
tests.

Add libmsc function msc_tx_common_id() to call the above. Add this mostly to
clearly indicate in msc_ifaces.h that libmsc is calling out of the MSC; also
to do conn->via_iface checking.

Call msc_tx_common_id() after ciphering is established, in
_gsm48_rx_mm_serv_req_sec_cb()'s GSM_SECURITY_SUCCEEDED case.

Change-Id: I576ddd5bbabfc989149debd2f8a9743db6d26043

2 files changed, 38 insertions, 0 deletions

diff --git a/openbsc/src/libiu/iu.c b/openbsc/src/libiu/iu.c
index 8ba6fa49d..696527dca 100644
--- a/openbsc/src/libiu/iu.c
+++ b/openbsc/src/libiu/iu.c
@@ -256,6 +256,25 @@ int iu_tx_sec_mode_cmd(struct ue_conn_ctx *uectx, struct gsm_auth_tuple *tp,
 	return 0;
 }
 
+int iu_tx_common_id(struct ue_conn_ctx *uectx, const char *imsi)
+{
+	struct msgb *msg;
+	struct osmo_scu_prim *prim;
+
+	LOGP(DRANAP, LOGL_INFO, "Transmitting RANAP CommonID (SUA link %p conn_id %u)\n",
+	     uectx->link, uectx->conn_id);
+
+	msg = ranap_new_msg_common_id(imsi);
+	msg->l2h = msg->data;
+	prim = (struct osmo_scu_prim *) msgb_push(msg, sizeof(*prim));
+	prim->u.data.conn_id = uectx->conn_id;
+	osmo_prim_init(&prim->oph, SCCP_SAP_USER,
+			OSMO_SCU_PRIM_N_DATA,
+			PRIM_OP_REQUEST, msg);
+	osmo_sua_user_link_down(uectx->link, &prim->oph);
+	return 0;
+}
+
 static int iu_grnc_id_parse(struct iu_grnc_id *dst,
 			    struct RANAP_GlobalRNC_ID *src)
 {
diff --git a/openbsc/src/libmsc/msc_ifaces.c b/openbsc/src/libmsc/msc_ifaces.c
index 500c99c2e..85e293107 100644
--- a/openbsc/src/libmsc/msc_ifaces.c
+++ b/openbsc/src/libmsc/msc_ifaces.c
@@ -23,6 +23,10 @@
 #include <openbsc/debug.h>
 #include <openbsc/gsm_data.h>
 #include <openbsc/msc_ifaces.h>
+#include <openbsc/iu.h>
+#include <openbsc/gsm_subscriber.h>
+
+#include "../../bscconfig.h"
 
 static int msc_tx(struct gsm_subscriber_connection *conn, struct msgb *msg)
 {
@@ -81,3 +85,18 @@ int msc_gsm48_tx_mm_serv_rej(struct gsm_subscriber_connection *conn,
 
 	return msc_tx_dtap(conn, msg);
 }
+
+int msc_tx_common_id(struct gsm_subscriber_connection *conn)
+{
+	/* Common ID is only sent over IuCS */
+	if (conn->via_ran != RAN_UTRAN_IU)
+		return 0;
+
+#ifdef BUILD_IU
+	return iu_tx_common_id(conn->iu.ue_ctx, conn->subscr->imsi);
+#else
+	LOGP(DMM, LOGL_ERROR,
+	     "Cannot send CommonID: RAN_UTRAN_IU but IuCS support not built\n");
+	return -ENOTSUP;
+#endif
+}