Cellular Network Infrastructure » Core Network (CN) » OsmoGGSN (former OpenGGSN)

I've started writing a test in osmo-ttcn3-hacks.git, osmith/wip branch. After spending some time to figure out the right syntax to pass the extension headers from the test to the code that encodes the GTP frames, I have the test almost working.

The current obstacle is, the GTP encoder seems to ignore the lengthfield inside the GTPU_ExtensionHeader. For example, I set it to 4, and in wireshark I see it is at 1 (in the hexdump) and the packet shows up as malformed packet.

For the record, I made these scripts with containers, they need a bit of work, I would like to integrate them into kernel/selftests infrastructure under the Linux kernel tree. I think these can be complementary each other.

There is a new centralized dashboard (courtesy of Jakub Kicinski) which provides CI for the Linux NetDev tree since a few weeks. I can request Jakub to include these tests to be monitored there.

I guess there is a degree of overlap with Oliver's work, but I needed this to validate my development work at basic level and, coindentally, I just learnt recently that you never have sufficient tests for the work you do :)

Attached the sketches for reference, generalizing them for kernel/selftest should take 1-2 hours maximum.

They even cover GTP tunnel dualstack which is something that was not actually in the requirements, but I realised it came for free with the recent work that has been done.

Let me know if you agree, otherwise, I will just keep them as sketch scripts locally.