Hi all!
As some of you might have seen from the various git commit messages, I spent
quite a bit of time to implement a GSM 12.21 (A-bis OML) plugin for wireshark
from scratch. It's available in our git repository at /wireshark/abis_oml.patch
My main focus has been the parsing of the ip.access vendor-specific extensions
to 12.21, as that part is much harder than just implementing what's written
in TS 12.21 itself.
One of the things that it can now decode is decoding of the 'network listen'
functionality implemented as 12.21 'perform test'.
Using this, you can scan over all ARFCN and report the rx level (good for
determining an unused channel at your current location), or you can actually
decode the BCCH information of all cells in your vicinity.
This is just the wireshark plugin. I did not write any FOSS code for actually
starting those tests, you still need some non-free software for that. However,
looking at the pcap file I sent some time ago and at this wireshark plugin,
anyone interested should be able to implement this very quickly, maybe as an
addition to ipaccess-config.
Due to my current lack of access to BS-11 hardware, the plugin was not yet
tested against it. If anyone can do some testing in this regard, it would
be much appreciated. Alternatively, if somebody can send me some BS11 pcap
files (maybe just of OpenBSC starting up), I can make sure to fix it.
I'm planning to do some more work regarding cleanup and feature-completeness of
the plugin before submitting it mainline to wireshark.
However, the Abis-IP plugin should be quite complete and I'll plan to submit
it really soon now.
Regards,
--
- Harald Welte <laforge(a)gnumonks.org> http://laforge.gnumonks.org/
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"Privacy in residential applications is a desirable marketing option."
(ETSI EN 300 175-7 Ch. A6)
