Wireshark-dev: Re: [Wireshark-dev] Can a Lua dissector access Wireshark preferences?
From: "Maynard, Chris" <[email protected]>
Date: Thu, 30 Aug 2018 16:42:06 +0000

If you look at the documentation for ProtoField.new and friends[1], you can see that there’s a “mask” argument.  That specifies how many bits applies to this field.

 

So for example, below there are 2 fields, field1 is the upper nibble of a byte, field2 is the lower nibble of a byte:

 

local foo_field1 = ProtoField.uint8("foo.field1", "Field1", base.DEC, nil, 0xf0)

local foo_field2 = ProtoField.uint8("foo.field2", "Field2", base.DEC, nil, 0x0f)

 

- Chris

 

[1]: https://www.wireshark.org/docs/wsdg_html_chunked/lua_module_Proto.html#lua_class_ProtoField

 

 

From: Wireshark-dev [mailto:[email protected]] On Behalf Of David Aldrich
Sent: Thursday, August 30, 2018 11:51 AM
To: [email protected]
Subject: [Wireshark-dev] Can a Lua dissector access Wireshark preferences?

 

Hi

 

For my lua dissector, I want to be able to specify the bit width of a data field using a Wireshark Preference.

 

Is that possible?  If so, where would I find some help on how to do it?

 

Best regards

 

David

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