IuUP: Allow Initialization with set rem IP address and unset rem port

Do not refuse IuUP Initialization messages coming in on an RTP port if
the remote port is not yet known.
If an IUFP conn is not yet configured (pre-Initialization), allow rx
from any address or port.

An osmo-mgw client (eg. osmo-hnbgw) may wish to initially set a remote
IP address as a hint during CRCX, hence the IP address may already be
set while the port may be unset.

Related: SYS#6657
Change-Id: Idd833997abce46886e9664505b2776fa5dadc8db
---
M src/libosmo-mgcp/mgcp_network.c
1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/src/libosmo-mgcp/mgcp_network.c b/src/libosmo-mgcp/mgcp_network.c
index 994ce45..674c096 100644
--- a/src/libosmo-mgcp/mgcp_network.c
+++ b/src/libosmo-mgcp/mgcp_network.c
@@ -834,7 +834,8 @@
 {
 	char ipbuf[INET6_ADDRSTRLEN];
 
-	if (osmo_sockaddr_is_any(&conn->end.addr) != 0) {
+	if (osmo_sockaddr_is_any(&conn->end.addr) != 0 ||
+	    osmo_sockaddr_port(&conn->end.addr.u.sa) == 0) {
 		if (mgcp_conn_rtp_is_iuup(conn) && !conn->iuup.configured) {
 			/* Allow IuUP Initialization to get through even if we don't have a remote address set yet.
 			 * This is needed because hNodeB doesn't announce its IuUP remote IP addr to the MGCP client

