netdev - Re: DDoS attack causing bad effect on conntrack searches

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Message-ID: <4BD1784A.6010306@trash.net>
Date:	Fri, 23 Apr 2010 12:36:58 +0200
From:	Patrick McHardy <kaber@...sh.net>
To:	Eric Dumazet <eric.dumazet@...il.com>
CC:	Jesper Dangaard Brouer <hawk@...u.dk>, paulmck@...ux.vnet.ibm.com,
	Changli Gao <xiaosuo@...il.com>, hawk@...x.dk,
	Linux Kernel Network Hackers <netdev@...r.kernel.org>,
	Netfilter Developers <netfilter-devel@...r.kernel.org>
Subject: Re: DDoS attack causing bad effect on conntrack searches

Eric Dumazet wrote:
> Le jeudi 22 avril 2010 à 23:03 +0200, Eric Dumazet a écrit :
>>> Guess I have to reproduce the DoS attack in a testlab (I will first have 
>>> time Tuesday).  So we can determine if its bad hashing or restart of the 
>>> search loop.
>>>
> 
> Or very long chains, if attacker managed to find a jhash flaw.

That should be visible in the "searched" statistic.

> You could add a lookup_restart counter :

I've applied Jespers equivalent patch.
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