Implement IuCS (large refactoring and addition)

osmo-nitb becomes osmo-msc
add DIUCS debug log constant
add iucs.[hc]
add msc vty, remove nitb vty
add libiudummy, to avoid linking Iu deps in tests
Use new msc_tx_dtap() instead of gsm0808_submit_dtap()
libmgcp: add mgcpgw client API
bridge calls via mgcpgw

Enable MSC specific CTRL commands, bsc_base_ctrl_cmds_install() still needs to
be split up.

Change-Id: I5b5b6a9678b458affa86800afb1ec726e66eed88
diff --git a/include/openbsc/mgcp.h b/include/openbsc/mgcp.h
index b2262bc..7cf83b2 100644
--- a/include/openbsc/mgcp.h
+++ b/include/openbsc/mgcp.h
@@ -170,6 +170,21 @@
 	MGCP_BSC_NAT,
 };
 
+enum mgcp_connection_mode {
+	MGCP_CONN_NONE = 0,
+	MGCP_CONN_RECV_ONLY = 1,
+	MGCP_CONN_SEND_ONLY = 2,
+	MGCP_CONN_RECV_SEND = MGCP_CONN_RECV_ONLY | MGCP_CONN_SEND_ONLY,
+	MGCP_CONN_LOOPBACK  = 4 | MGCP_CONN_RECV_SEND,
+};
+
+extern const struct value_string mgcp_connection_mode_strs[];
+
+static inline const char *mgcp_cmode_name(enum mgcp_connection_mode mode)
+{
+	return get_value_string(mgcp_connection_mode_strs, mode);
+}
+
 struct mgcp_config {
 	int source_port;
 	char *local_ip;