Re: Handling TCP packets reordering

[Sake Blok <sake () euronet nl>]

On 4 mei 2011, at 22:11, Jeff Morriss wrote:

> Max Dmitrichenko wrote:
> > Hi!
> > I'm continue to write dissector for an encrypted protocol. Everything
> > works fine until I receive an out-of-order TCP segment, i.e. previous
> > was lost.
> > Since I'm trying to decrypt it, I fail with it and break the whole
> > decryption context. Is there any way to:
> > 1) Detect that this packet is out of order in given conversation?
> > 2) Ask the TCP dissector to feed this packet later again when all
> > previous segments will be retransmitted?
>
> I would think desegment_tcp() should be able to handle this by not calling your dissector for an out-of-order 
> segment: it should be able to only call your dissector once it has a completely reassembled (desegmented) PDU.  
> Looking through the code, it's not immediately obvious to me what the problem is.

One case that can cause a problem is when the first segment of a PDU is received out-of-order. Or did your recent work 
also handle this exception, Jeff?

Cheers,


Sake

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