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From: "Fabien C." <7o5fzvj4duxjxzp@jetable.org>
To: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Florian Westphal <fw@strlen.de>, netfilter-devel@vger.kernel.org
Subject: Re: libnetfilter_queue: Some accepted packets get lost
Date: Thu, 10 Mar 2011 22:21:18 +0100	[thread overview]
Message-ID: <4D7940CE.8080602@jetable.org> (raw)
In-Reply-To: <4D78D77E.6040703@netfilter.org>

>> perhaps you're hitting this problem?:
>> http://marc.info/?l=netfilter-devel&m=129016166319433&w=2
>> It triggers when your receive a 2nd UDP packet with the same
>> address/port pair while the 1st packet is still queued.
> 
> Fabien, to confirm that this is the problem, please use the following rule:
> iptables -A OUTPUT -t raw -p udp --dport 53 -j NFQUEUE --queue-num 666
> and retest. Let us know if that fixed it.

Yes, that fixed it, thank you for the information!

It's just a bit sad not being able to use conntracking, it avoided some packets
going through userland once one had already been accepted on the same source
ip/port.

Do you think it's not technically possible to fix that race condition in a
proper way?

Fabien

      reply	other threads:[~2011-03-10 21:21 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-03-04 23:04 libnetfilter_queue: Some accepted packets get lost Fabien C.
2011-03-09 13:44 ` Pablo Neira Ayuso
2011-03-09 23:27   ` Fabien C.
2011-03-10  6:29     ` Florian Westphal
2011-03-10 13:51       ` Pablo Neira Ayuso
2011-03-10 21:21         ` Fabien C. [this message]

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