Add some Iu-CS functions (in the wrong place though, wip)

1 files changed, 78 insertions, 0 deletions

diff --git a/openbsc/src/gprs/iu.c b/openbsc/src/gprs/iu.c
index f30d844ac..0c1650d74 100644
--- a/openbsc/src/gprs/iu.c
+++ b/openbsc/src/gprs/iu.c
@@ -460,3 +460,81 @@ int iu_init(void *ctx, const char *listen_addr, uint16_t listen_port,
 	user = osmo_sua_user_create(ctx, sccp_sap_up, ctx);
 	return osmo_sua_server_listen(user, listen_addr, listen_port);
 }
+
+/* Return an existing Iu-CS subscriber connection record for the given link and
+ * connection IDs, or return NULL if not found. */
+static struct gsm_subscriber_connection *subscr_conn_lookup_iu(struct gsm_network *network,
+							       uint8_t link_id,
+							       uint32_t conn_id)
+{
+	struct gsm_subscriber_connection *conn;
+	llist_for_each_entry(conn, &network->subscr_conns, entry) {
+		if (conn->via_iface != IFACE_IUCS)
+			continue;
+		if (conn->iu.link_id != link_id)
+			continue;
+		if (conn->iu.conn_id != conn_id)
+			continue;
+		return conn;
+	}
+	return NULL;
+}
+
+/* Receive MM/CC message from Iu-CS (SCCP user SAP).
+ * msg->dest must reference a struct ue_conn_ctx. link_id identifies the SCTP
+ * peer that sent the msg.
+ *
+ * For A-interface see libbsc/bsc_api.c gsm0408_rcvmsg(). */
+int gsm0408_rcvmsg_iucs(struct gsm_network *network, struct msgb *msg, uint8_t link_id)
+{
+	int rc;
+	struct ue_conn_ctx ue_ctx;
+	struct gsm_subscriber_connection conn;
+
+	ue_ctx = msg->dest;
+
+	/* TODO: are there message types that could allow us to skip this
+	 * search? */
+	conn = subscr_conn_lookup_iu(network, link_id, ue_ctx->conn_id);
+
+	if (lchan->conn) {
+		/* if we already have a connection, handle DTAP.
+		   gsm0408_dispatch() is aka msc_dtap() */
+		gsm0408_dispatch(conn, msg);
+	} else {
+		/* allocate a new connection */
+		rc = BSC_API_CONN_POL_REJECT;
+		conn = subscr_conn_allocate_iu(msg->lchan);
+		if (!lchan->conn) {
+			lchan_release(lchan, 1, RSL_REL_NORMAL);
+			return -1;
+		}
+
+		/* fwd via bsc_api to send COMPLETE L3 INFO to MSC */
+		rc = api->compl_l3(lchan->conn, msg, 0);
+
+		if (rc != BSC_API_CONN_POL_ACCEPT) {
+			lchan->conn->lchan = NULL;
+			subscr_con_free(lchan->conn);
+			lchan_release(lchan, 1, RSL_REL_NORMAL);
+		}
+	}
+
+	return 0;
+}
+
+/* For A-interface see libbsc/bsc_api.c subscr_con_allocate() */
+struct gsm_subscriber_connection *subscr_conn_allocate_iu(struct gsm_bts *bts)
+	/* TODO "bts"? this is an hNodeB, really. */
+{
+	struct gsm_subscriber_connection *conn;
+
+	conn = talloc_zero(bts->network, struct gsm_subscriber_connection);
+	if (!conn)
+		return NULL;
+
+	conn->via_iface = IFACE_IUCS;
+	conn->bts = bts;
+	llist_add_tail(&conn->entry, &bts->network->subscr_conns);
+	return conn;
+}