Wireshark · Wireshark-dev: Re: [Wireshark-dev] Unable to detect custom protocol dissector

[Anders Broman <anders.broman@xxxxxxxxxxxx>]

 

 

From: Wireshark-dev <wireshark-dev-bounces@xxxxxxxxxxxxx> On Behalf Of Graham Bloice
Sent: den 13 februari 2020 11:09
To: Developer support list for Wireshark <wireshark-dev@xxxxxxxxxxxxx>
Subject: Re: [Wireshark-dev] Unable to detect custom protocol dissector

 

Does your custom build of Wireshark include Lua?  What does the Help | About Wireshark | Wireshark info show?

 

On Wed, 12 Feb 2020 at 21:46, sandip gangakhedkar <sandipfloyd@xxxxxxxxx> wrote:

Hi,

 

I am using a Custom protocol dissector (Lua script) for the GeoNetworking header. I have build wireshark 3.2.1 from source on Ubuntu 18.04 and placed the Lua script in the Global plugins directory. However, the script fails when to find the Geonetworking protocol when I invoke it in the script:

 

  Dissector.get("gnw"):call(newTvb, pkt, root)

 

So I tried another approach:

 

  gnw_dissector = DissectorTable.get("ethertype"):get_dissector(35143)

 

The protocol gnw (GeoNetworking) corresponds to an EtherType of 35143 in my Wireshark protocols configuration. However, this also fails to find the "gnw" protocol.

 

How can I get wireshark to detect the GeoNetworking protocol from my custom Lua script?

 

Thanks in advance.

 

 

The function DissectorTable.get("ethertype"):get_dissector(35143)

https://wiki.wireshark.org/LuaAPI/Dissector#dissectortable:get_dissector.28pattern.29

gets the handle of the built in GNW dissector as far as I can tell. Is that what you want? Why do you want to replace the existing dissector? (If that’s what you are trying to do).

 

Regards

Anders

 

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