Wireshark · Ethereal-dev: Re: [Ethereal-dev] Arbitrarily choosing a protocol

[Guy Harris <gharris@xxxxxxxxx>]

Yann Samama wrote:

> Is it possible to call an upper-level dissector from a lower-level 
> dissector even if the upper-level dissector has not registered itself by 
> its name?

Not unless the upper-level dissector has registered itself in a 
dissector table and your lower-level dissector can use that dissector 
table.  For example, if the lower-level protocol header includes an 
Ethernet type field, it can use the dissector table for Ethernet types 
(and, in fact, *should* do so, rather than handling the Ethernet type 
itself).

> My goal is to achieve this without modifying the source code of the 
> upper-level dissector.

Given that Ethereal is free software, why is that a goal?  If you need 
some particular dissector to register itself by name, you could just 
modify Ethereal to do that, and send us a patch so that, in the next 
release, you don't have to modify Ethereal.  This means that your 
lower-level dissector won't work with an unmodified Ethereal, so you 
might have to build it yourself for the platforms on which it needs to 
run until a release comes out with your change, but if you can live with 
that restriction....