Wireshark-users: Re: [Wireshark-users] Lua scripting (obtaining protocol fields)
From: "Luis EG Ontanon" <[email protected]>
Date: Tue, 11 Sep 2007 21:37:20 +0200
On 9/11/07, Dan Siemon <[email protected]> wrote:
> However, I haven't been able to figure out how I can get access to parts of
> the packet data that are not covered by the display filter syntax. The
> particular example I am working on now involves obtaining the answers in a
> DNS response packet.

dnsExtractor = Field.new(" dns")

function tap.packet(pinfo, tvb, userdata)
       local dns_tvb = Tvb.new_real(dnsExtractor())
       local id = dns_tvb(0,2):get_uint() -- tvbrange:get_uint()
end

but that means redissecting dns...

BTW:
 For which fields the dns dissector does not have display filter fields?


if there are multiple instances of a field in a given packet you can
get a table with them all this way:

xxxs_table = {xxxExtractor()}

or you can:

value1, value2 =  xxxExtractor();


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