Ethereal-dev: AW: [Ethereal-dev] dissecting PDU with variable length

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From: Lars Dörner <mail@xxxxxxxxx>
Date: Thu, 12 Jan 2006 17:01:18 +0100
Hello


First I have to get the information how many crypted Datastreams there are
in the PDU. 
Then I have to get the Header of the first stream (including 8B Struct and
4B encoding type)
This informations I hand over to a Decoder which is counting the Data Bytes
included in the stream. But because of the unknown length I have to recall
this function when tcp segment ends (remembering where I am in the PDU) and
continue with the next TCP Segment in this PDU. After reaching the end the
Decoder give over the Length of the stream an the next header is to dissect.
This continues till the last stream in the PDU is dissected. 

I don`t need the information in the stream but I have to know each struct,
each encoding and each stream length. 

I hope it`s easier to understand now.  

THX,
LD



-----Ursprüngliche Nachricht-----
Von: ethereal-dev-bounces@xxxxxxxxxxxx
[mailto:ethereal-dev-bounces@xxxxxxxxxxxx] Im Auftrag von Jaap Keuter
Gesendet: Donnerstag, 12. Januar 2006 16:13
An: Ethereal development
Betreff: Re: [Ethereal-dev] dissecting PDU with variable length

Hi,

Lets see:

	2B std info
	2B encoding count
		8B struct
		4B encoding type
		?B encoded data
		8B struct
		4B encoding type
		?B encoded data
		... repeat 'encoding count' times

So how do you know you've reached the end of the encoded data, so where
the new encoding block begins? Is it defined by the encoding type, or
derived from the decoded data?

Thanx,
Jaap