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Wireshark-dev: [Wireshark-dev] How can I decode ASN.1 as Wireshark does?

From: "Abelardo Rodriguez-Trilla" <artrilla@xxxxxxxxx>
Date: Fri, 29 Feb 2008 18:42:35 +1930
Hi people.

I'm developing a VoIP protocol analyzer for a University educative module, for learning VoIP signalling protocols. I'm working with SIP and H.323. The SIP part is ready, and the Q.931 part of H.323 is also ready. But now I'm having issues with  the ASN.1 enconding of H.225.0 and H.245. I know that first I need to compile the ASN.1 tree to the language of my preference (C in this case), and it is already done. But besides the structures generated by the compiler, now I need to develop the decoding routines, which have to work with the PER alligned rules.

I wanted to know how Wireshark does to decode it?

Thanks in advance.

--
Abelardo Rodríguez-Trilla
"If you really want to do something, you'll find a way; if you don't, you'll find an excuse" Anonymous