Hi Tom,
From: Tom Uijldert Subject: RE: WTP reassembly patch; alternatives please
Date: Thu, 13 Dec 2001 11:20:23 +0100
I'd propose to skip the OVERLAP-checking in that case as overlapping is
impossible with sequence-blocks. As for receiving an existing
sequence-block, that could be a re-transmission and then the size could
differ.
Are you certain that the size could differ for retransmissions?
If the size can differ for retransmissions (due to the stack collapsing
multiple blocks into one) and if the only way to identify the block
is by its sequence number, then I think it would be impossible for the
receiving host to reliably reassemble the payload.
Well, I will add fragment_add_seq() tonight but I will
make it handle retransmissions in the following way:
IF a retransmitted block is received we will verify that both the size
and the content of the block is identical to the first received block
or else FD_OVERLAPCONFLICT will be set.
I think this would make most sense since I belive this behaviour would be
most sane and useful for a generic fragment_add_seq().
Please, IF you are certain that WTP CAN collapse multiple blocks and thus
send retransmissions with different block sizes tell me, because
then we must make some more changes (in that case, just ignoring the
retransmitted
blocks is not sufficient for reliable reassembly)
As I won't be able to do anything significant for the next month or so and
am not really comfortable with that part of the code, you doing the changes
would be very much appreciated.
OK. I will add fragment_add_seq() and I can change the WTP code to
use it.
However I can not test the changes since I have no WTP captures which are
fragmented.
When I have produced a patch, could I send it to you for testing
before it gets checked in?
best regards
ronnie sahlberg
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