OpenBSC system_information branch

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Harald Welte laforge at gnumonks.org
Thu Oct 22 09:18:09 UTC 2009


Hi!

I've updated the system_information branch.  The purpose of this branch
is to move away from static u_int8_t arrays that are used as templates
for the SYSTEM INFORMATION messages.  Thise arrays are reminiscent of the
old days of bs11_init, where everything had been done this way.

The current head of system_information is now managing to actually do that.
The full SI1-SI4 on the BCCH as well as the SI5/SI6 on the SACCH are now
created from scratch (see code in system_information.c)

The content of the SI is "phase 1" content, i.e. before rest octets were
introduced

I've also written some code to generate the rest octets, as well as a some
"rest octet encoding aware" bit vector routines that understand the meaning of
0/1/L/H.

However, those rest octet routines are not yet used.  They need some careful
testing before use.  Testing is actually quite hard, as not even wireshark
has dissector for the system information messages (anyone interested in
contributing on this? It's needed for airprobe, too)

One interesting bit that stalled development for quite some time:  If you send
a SACCH FILLing with length > 18 bytes, then the nanoBTS will actually crash
somewhere in the layer 2, sending you long error strings with addresses
(stack?) as error reports before rebooting :)

Feel free to start testing the system_information branch if you're interested.
I'd be happy to hear any "master works for my phone, but system_information
branch confuses my phone" kind of reports.

Regards,
	Harald
-- 
- Harald Welte <laforge at gnumonks.org>           http://laforge.gnumonks.org/
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