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Re: [Linphone-developers] patch to fix ZRTP sequence number handling
From: |
Guillaume Beraudo |
Subject: |
Re: [Linphone-developers] patch to fix ZRTP sequence number handling |
Date: |
Tue, 7 May 2013 09:25:37 +0200 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
Hi Eli,
Thanks for the information.
I think we will integrate the patch, though it seems to me very strange to
receive chaotical sequence numbers.
Why are you using such a strange zrtp stack as Groundwire's?
Cheers,
Guillaume
On Tue, Apr 30, 2013 at 12:46:12PM -0400, Eli Burke wrote:
> Attached is a patch to oRTP that fixes incorrect handling of ZRTP sequence
> numbers. We encountered a consistent error when connecting between Linphone
> and Groundwire using ZRTP (note: compatibility with Groundwire requires my
> previously submitted zrtp-hash patch).
>
> Bug details: Linphone sends ZrtpHello and receives Groundwire's ZrtpHelloAck,
> followed by ZrtpHello with a lower sequence number. This packet gets dropped
> with the error "Discarding received out of order zrtp packet:..." and
> Linphone never completes the ZRTP handshake.
>
> Though you may conclude that Groundwire is misbehaving, it is in fact in
> compliance with the RFC, which simply says:
> > The Sequence Number is a count that is incremented for each ZRTP
> > packet sent. The count is initialized to a random value. This is
> > useful in estimating ZRTP packet loss and also detecting when ZRTP
> > packets arrive out of sequence.
>
> http://tools.ietf.org/html/rfc6189#section-5
>
> I have confirmed with Werner Dittmann (author of ZrtpCpp) that the sequence
> number is only intended for diagnostic purposes and not for enforcing any
> kind of packet ordering.
>
> _______________________________________________
> Linphone-developers mailing list
> address@hidden
> https://lists.nongnu.org/mailman/listinfo/linphone-developers
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- Re: [Linphone-developers] patch to fix ZRTP sequence number handling,
Guillaume Beraudo <=