OsmoBTS sends empty frames on BCCH for TC=5
When no SI 2bis, nor 2ter, nor 2quater is in use, then the code in bts_sysinfo_get() will return null, causing the transmission of a dummy frame (0303012B2B2B2B2B2B2B2B2B2B2B2B2B2B2B2B2B2B2B2B) instead of a system information message. This is - at least - very odd and might not be backed by the specification. We should simply send any other system information message instead of sending a frame that does not have a valid SI header.
While 030301 might be a valid, empty UI frame on a DCCH, it is not a valid frame for the BCCH, where the header is structured differently.
In fact, bts_sysinfo_get() should never return NULL and always return a valid BCCH message.
This bug was found while developing http://git.osmocom.org/osmo-ttcn3-hacks/tree/sysinfo/Test.ttcn
- Assignee changed from sysmocom to laforge
- % Done changed from 0 to 80
Fix submitted as https://gerrit.osmocom.org/3259 - pending review.
http://git.osmocom.org/osmo-ttcn3-hacks/tree/sysinfo is being developed to catch bugs like this.