iucs: Add a function to return the connection ID for the IU SCCP conn

Change-Id: Ica4a7f463fcf1bd67fe082296cecea8d10f2fc5b

include/osmocom/msc/iucs.h

@@ -8,3 +8,5 @@ int gsm0408_rcvmsg_iucs(struct gsm_network *network, struct msgb *msg,
 struct gsm_subscriber_connection *subscr_conn_lookup_iu(struct gsm_network *network,
 							struct ranap_ue_conn_ctx *ue);
 int iu_rab_act_cs(struct gsm_trans *trans);
+
+uint32_t iu_get_conn_id(const struct ranap_ue_conn_ctx *ue);

src/libmsc/iu_dummy.c

@@ -90,4 +90,10 @@ int ranap_iu_tx_release(struct ranap_ue_conn_ctx *ctx, const struct RANAP_Cause
 	return 0;
 }
 
+uint32_t iu_get_conn_id(const struct ranap_ue_conn_ctx *ue)
+{
+	LOGP(DLGLOBAL, LOGL_INFO, "iu_get_conn_id() dummy called, returning BOGUS value\n");
+	return 23;
+}
+
 #endif

src/libmsc/iucs.c

@@ -251,3 +251,7 @@ int iu_rab_act_cs(struct gsm_trans *trans)
 	return 0;
 }
 
+uint32_t iu_get_conn_id(const struct ranap_ue_conn_ctx *ue)
+{
+	return ue->conn_id;
+}