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Wireshark-dev: Re: [Wireshark-dev] general inquiry on building dissectors for wireshark-3.4.4

From: Graham Bloice <graham.bloice@xxxxxxxxxxxxx>
Date: Wed, 7 Apr 2021 18:46:15 +0100


On Wed, 7 Apr 2021 at 17:28, Vincent Randal <vtrandal@xxxxxxxxx> wrote:
Hello,

Where can I find a complete "text based" dissector example that builds with the current Wireshark cmake build method used in wireshark-3.4.4? Does that question even make sense? I fear most people reading my question won't understand what I'm after.

I've watched numerous YouTube videos by Graham Bloice and Richard Sharpe that describe 3 primary methods for Wireshark dissector development:
1. Text based
2. Scripting Language based
3. C based

In the meantime I have built wireshark-2.6.20 using the older ./autogen.sh, configure, make build method. This gives me hope I might have some success with at least 1 (one) text-based dissector example that uses that build method:


The text based dissector in my presentation was specifically WSGD which provides its own runtime via a plugin DLL.  It's a bit of a grey area if an ASN.1 dissector is text based, as the description is fed into the dissector generator asn2wrs.py and out pops a C-based dissector.
 
If I were an expert with cmake (which might be easier than I think) I would probably update the text-based examples to build using cmake. But I don't know how to do that (yet).

Adding a dissector with CMake is easier (I think)  as it mostly handles platform and compiler differences.  As such the page you link to (which is the old wiki, not our new shiny GitLab one, https://gitlab.com/wireshark/wireshark/-/wikis/ASN1_plugin) is woefully out of date as it doesn't describe how to do that with CMake.

Unfortunately I've never dealt with an asn1 based dissector, either built-in or as a plugin so can't offer advice on that.


Vincent Randal
Longmont, CO

--
Graham Bloice