Ethereal-dev: Re: [Ethereal-dev] Re: TCP retransmission in BGP dissector

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From: "Ronnie Sahlberg" <ronnie_sahlberg@xxxxxxxxxxxxxx>
Date: Tue, 15 Apr 2003 20:27:12 +1000
----- Original Message -----
From: "Guy Harris"
To: "Ronnie Sahlberg"
Sent: Tuesday, April 15, 2003 7:59 PM
Subject: Re: [Ethereal-dev] Re: TCP retransmission in BGP dissector



> Note that the dissector won't be able to indicate how many bytes there
> are until the next PDU starts if the PDU header that has a length is
> split across segment boundaries and you're looking at the first segment,
> because you'll have to do desegmentation just to find out how big the
> packet is.

Yes, that is a good point that unfortunately killed my idea.

A desegmenting dissector sometimes will request only partial reassembly in
order to get just enough data to
do a second dissection attempt which will again result in more_data_needed.
The first "reassemble more data" will then not point to a new pdu header and
thus we should not store it.

Hm. need more brain applied.
It would have been nice though, making existing variables more generic and
enhancing its semantics.

If worst comes to it, I'll just have to add another field to pinfo but
desegment_len is already so close
semantically to what is needed it would feel wrong not to use it for this as
well.