From: Patrick McHardy <kaber@trash.net>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Changli Gao <xiaosuo@gmail.com>,
hawk@comx.dk, Jesper Dangaard Brouer <hawk@diku.dk>,
paulmck@linux.vnet.ibm.com,
Linux Kernel Network Hackers <netdev@vger.kernel.org>,
Netfilter Developers <netfilter-devel@vger.kernel.org>
Subject: Re: DDoS attack causing bad effect on conntrack searches
Date: Tue, 01 Jun 2010 12:41:38 +0200 [thread overview]
Message-ID: <4C04E3E2.7020209@trash.net> (raw)
In-Reply-To: <1275388310.2738.2.camel@edumazet-laptop>
Eric Dumazet wrote:
> Le mardi 01 juin 2010 à 12:18 +0200, Patrick McHardy a écrit :
>
>> If a new conntrack is created in PRE_ROUTING or LOCAL_OUT, it will be
>> added to the unconfirmed list and moved to the hash as soon as the
>> packet passes POST_ROUTING. This means the number of unconfirmed entries
>> created by the network is bound by the number of CPUs due to BH
>> processing. The number created by locally generated packets is unbound
>> in case of preemptible kernels however.
>>
>
> OK, we should have a percpu list then.
Yes, that makes sense.
> BTW, I notice nf_conntrack_untracked is incorrectly annotated
> '__read_mostly'.
>
> It can be written very often :(
>
> Should'nt we special case it and let be really const ?
That would need quite a bit of special-casing to avoid touching
the reference counts. So far this is completely hidden, so I'd
say it just shouldn't be marked __read_mostly. Alternatively we
can make "untracked" a nfctinfo state.
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next prev parent reply other threads:[~2010-06-01 10:41 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-22 12:58 DDoS attack causing bad effect on conntrack searches Jesper Dangaard Brouer
2010-04-22 13:13 ` Changli Gao
2010-04-22 13:17 ` Patrick McHardy
2010-04-22 14:36 ` Eric Dumazet
2010-04-22 14:53 ` Eric Dumazet
2010-04-22 15:51 ` Paul E. McKenney
2010-04-22 16:02 ` Eric Dumazet
2010-04-22 16:34 ` Paul E. McKenney
2010-04-22 20:38 ` Jesper Dangaard Brouer
2010-04-22 21:03 ` Eric Dumazet
2010-04-22 21:14 ` Eric Dumazet
2010-04-22 23:44 ` David Miller
2010-04-23 5:44 ` Eric Dumazet
2010-04-23 8:13 ` David Miller
2010-04-23 8:18 ` David Miller
2010-04-23 8:40 ` Jesper Dangaard Brouer
2010-04-23 10:36 ` Patrick McHardy
2010-04-23 11:06 ` Eric Dumazet
2010-04-22 21:28 ` Jesper Dangaard Brouer
2010-04-23 7:23 ` Jan Engelhardt
2010-04-23 7:46 ` Eric Dumazet
2010-04-23 7:55 ` Jan Engelhardt
2010-04-23 9:23 ` Eric Dumazet
2010-04-23 10:55 ` Patrick McHardy
2010-04-23 11:05 ` Eric Dumazet
2010-04-23 11:06 ` Patrick McHardy
2010-04-23 20:57 ` Eric Dumazet
2010-04-24 11:11 ` Jesper Dangaard Brouer
2010-04-24 20:11 ` Eric Dumazet
2010-04-26 14:36 ` Jesper Dangaard Brouer
2010-05-31 21:21 ` Eric Dumazet
2010-06-01 0:28 ` Changli Gao
2010-06-01 5:05 ` Eric Dumazet
2010-06-01 5:48 ` Changli Gao
2010-06-01 10:18 ` Patrick McHardy
2010-06-01 10:31 ` Eric Dumazet
2010-06-01 10:41 ` Patrick McHardy [this message]
2010-06-01 16:20 ` [RFC nf-next-2.6] conntrack: per cpu nf_conntrack_untracked Eric Dumazet
2010-06-04 11:40 ` Patrick McHardy
2010-06-04 12:10 ` Changli Gao
2010-06-04 12:29 ` Patrick McHardy
2010-06-04 12:36 ` Eric Dumazet
2010-06-04 16:25 ` [PATCH nf-next-2.6] conntrack: IPS_UNTRACKED bit Eric Dumazet
2010-06-04 20:15 ` [PATCH nf-next-2.6 2/2] conntrack: per_cpu untracking Eric Dumazet
2010-06-08 14:29 ` Patrick McHardy
2010-06-08 14:52 ` Eric Dumazet
2010-06-08 15:12 ` Eric Dumazet
2010-06-09 12:45 ` Patrick McHardy
2010-06-08 14:12 ` [PATCH nf-next-2.6] conntrack: IPS_UNTRACKED bit Patrick McHardy
2010-04-23 10:56 ` DDoS attack causing bad effect on conntrack searches Patrick McHardy
2010-04-23 12:45 ` Jesper Dangaard Brouer
2010-04-23 13:57 ` Patrick McHardy
2010-04-22 13:31 ` Jesper Dangaard Brouer
2010-04-23 10:35 ` Patrick McHardy
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