OsmoHLR doesn't update VLR during UpdateLocation
For some reason, the VLR column in the HLR table is not updated when a subscriber performs an Update Location procedure.
What should go in the VLR column? We have the IPAC_IDTAG_SERNR producing something like "SGSN-00-00-00-00-00-00" and "MSC-00-00-00-00-00-00". The HLR also has sgsn_number and sgsn_address columns, could be set to the same / to the remote GSUP client address, by switching on osmo_gsup_message.cn_domain...
In a real 3GPP HLR with MAP, it's the global title of the respective VLR which is stored.
For us, it is "any other unique identifier of the VLR", and I think it hasn't been specified yet so far.
I'm against using the IP address, as this will break all kinds of dynamic address or NAT scenarios (which currently work as GSUP is a strict client->server protocol).
IDTAG_SERNR might be an idea, maybe also some other IDTAG? We should make it user-configurable then to ensure multiple MSCs have differnet identifiers.