Hi Benoit,
On Wed, Aug 01, 2018 at 09:34:27PM +0200, benoit michau wrote:
> This email to point to a recent development I made on CSN.1, which
> might be of interest to some of you.
Thanks a lot for implementing this in the first place, and also for
sharing information about it here.
It's amazing that we finally seem to be getting good CSN.1 tools
> I extracted and consolidated all
> CSN.1 definitions from 24.008, 44.018 and 44.060 (the "consolidation"
> part was quite hard...).
I think the biggest problems are the many syntax errors in the official CSN.1
syntax in the specs. I once tried to parse it from proprietaryt CSN.1 tools,
and it was a nightmare. In fact, there are companies selling the cleaned up
and fully confirming syntax for money.
Somebody should submit your fixed versin to 3GPP so they can release a correct
syntax at least...
> I have also developped a CSN.1 to Python
> translater, and a runtime to encode / decode any CSN.1 structures.
Thanks. What we need to figure out now is how to make best use of this from
within
Osmocom. OsmoPCU is - as you know - implemented in C. Rewriting it in python
is
unfortunately not an option, if not alone for performance reasons :/
However, it would be great if we could benefit from your work in other ways,
such as
a) for unit testing our code (particularly the hand-written encoders/decoders)
b) for integration testing. Unfortunately TTCN3/TITAN doesn't have any CSN.1
tools,
so we cannot use a "trusted, aut-generated" encoder/decoder from our existing
integration tests. However, maybe there are ways we can integrate your
python
CSN.1 with TTCN-3? MAybe it's possible to auto-generate ASN.1 syntax and an
ASN.1(BER)-to-CSN.1
transcoder in python. Then we could use TTCN3 templates in the TITAN world,
and
we'd simply call a function to encode as ASN.1-BER, and then into your
transcoder to create
CSN.1 from that (and vice versa)?
c) something like a MS-side (E)GPRS RLC/MAC implementation in python. We could
then use this
over "virtual/simulated" radio against OsmoPCU.
d) maybe generate C / C++ encoder/decoder from your python framework, since it
fully
parses and understands the syntax tree...
I'm not a python expert and I have not used your code yet, so I'm not sure what
is
realistic/possible. But for sure it would be really great to use generated
parser/encoders
for CSN.1 in one way or another...
If you (or anyone else) have any further ideas to share, please feel free to do
so!
Regards,
Harald
--
- Harald Welte <[email protected]> http://laforge.gnumonks.org/
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