At 03:51 PM 7/5/00, Gilbert Ramirez wrote:
On Wed, Jul 05, 2000 at 03:56:02AM -0500, Neil Hunter wrote:
>
>
> Hi,
> I've just started looking through the Ethereal code and documents, so
> apologies if this is covered elsewhere (but I haven't spotted it yet!).
>
> Is it possible to chain dissectors together?
>
> I'll explain the scenario in case I'm coming at this in the wrong way. WAP
> uses up to three separate protocols to carry its data and uses UDP as the
> transport. Therefore a UDP packet could contain WTLS, WTP or WSP data. The
> combination is (thankfully) defined by the port being used.
>
> [ ... ]
> I'd rather keep the protocol dissection separate if possible and not have a
> single wap dissector that splits everything up internally - but is this
> feasible?
Sure. Look at the ppp dissector for an example. It has both
dissect_ppp() and dissect_payload_ppp().
--gilbert
WAP is a stack rather than a protocol, thus WSP is carried in WTP a bit like
TCP is carried in IP. Indeed, I refer to port 9201 data as WSP/WTP.
This came up on the kannel mailing list.
Inherently a WTP dissector has to arrange for a 'superior' dissector to
continue the
process, just as packet-udp does, otherwise there is no point in starting.
I think
that this goes bit beyond and is more intimate that the relation between
ppp and payload_ppp, but perhaps we are just saying the same thing in different
words.
I have posted the URL to the WAP documents before, it is
< URL:http://www.wapforum.org/what/technical.htm >, those here
interested in network protocols might also want to look at
< URL:http://www.4k-associates.com/IEEE-L7-WAP-BIG.html >
I also think that the dissectors should be kept separate, so although
I consider this a WAP project and there is a single wap.h header file,
I have put the code into separate files wsp.c and wtp.c.
See my other posts. Thank you for your interest and your very clear
and helpful comments.
Ben.
P.S. It is not my choice that I am using broken software that cannot
emit a sig break. Consider it an innovation.
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