Wireshark-dev: Re: [Wireshark-dev] How to call a dissector from the llc dissector?
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From: Guy Harris <guy@xxxxxxxxxxxx>
Date: Wed, 20 May 2009 14:25:58 -0700

On May 20, 2009, at 2:15 PM, Guy Harris wrote:



On May 20, 2009, at 5:19 AM, Florian FAVIER wrote:


We are now writing a new dissector for the Asterix protocol,


I assume you mean "ASTERIX protocol":

	http://www.eurocontrol.int/asterix/public/subsite_homepage/homepage.html


and we would like to call it when the LLC dissector is running.

The condition is when the third byte of LLC is equal to 0x03, we
have to call our dissector.


In other words, the Asterix protocol prevents most SNAP-based or
otherwise 802.2-based protocols from working on any machine using it?
"When the third byte of LLC is equal to 0x03" is equivalent to "when
the packet is an LLC UI frame", and most packets on 802.2-based
networks are LLC UI frames.
If you *do* mean the ASTERIX protocol, then, at least according to Figure 1 in 

	http://www.comsoft.de/download/atc/background/rmcde_atca97.pdf
ASTERIX runs atop a transport or session-layer protocol, so its dissector should *NOT* be called by the LLC dissector.