implement GSUP messages for inter-MSC handover
For #3618 I need GSUP messages:
- definition in gsup.adoc
- implementation of decoding and encoding
- rudimentary message tests
so that I can just go on and use them when I'm ready.
- Checklist item get libosmocore patch merged added
- Checklist item osmo-gsm-manuals.git patch submit to gerrit added
- Checklist item osmo-gsm-manuals.git patch merged added
- % Done changed from 40 to 60
- Checklist item wireshark: submit patch added
- Checklist item wireshark: get patch merged added
This will take a bit until it gets merged (and then the other steps in the checklist follow), as neels wrote in gerrit:
In general, I would like to keep this patch unmerged before I have osmo-msc's inter-MSC HO pretty much complete and working. Likely more insights and needs about the protocol will arise from chiseling out the details. But it would be nice to continue the review process nevertheless; just not merge it yet (so we don't need to worry about api compat later).