tree e771aca63eb835cae980f3684e6e91c2684a52e7
parent f6db465082f7cf2864037a8bfa778ad144a90a6d
author Neels Hofmeyr <nhofmeyr@sysmocom.de> 1701658483 +0100
committer Pau Espin Pedrol <pespin@sysmocom.de> 1701780550 +0100

IuUP: allow Initialization from any address if not yet set

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

If we refuse the IuUP Initialization, a 3G RNC may fail to set up a RAB.
We will know the remote address only *after* assigning a RAB succeeded.
So the IuUP Initialization must be allowed before knowing all addresses.

At the time of writing, CRCX for IUFP are sent to osmo-mgw in either
LOOPBACK or in RECVONLY mode:
- current osmo-msc: recvonly
- osmo-msc <= v1.10.0: loopback
- osmo-hnbgw: loopback
IuUP Initialization should work regardless of that.
See also next patch I158dd046fdfcb10392cde3de8cc88dd095a05b40

IuUP is one layer below the loopback/send/recv decision for RTP; IuUP is
always terminated at the MGW, while the AMR payload carries through.

Related: alternative patch Idd833997abce46886e9664505b2776fa5dadc8db
Related: SYS#6657
Change-Id: I6c365559a7bd197349f0ea99f7a13b56a4bb580b