From: Pablo Neira Ayuso <pablo@netfilter.org>
To: Hans Schillstrom <hans.schillstrom@ericsson.com>
Cc: Jan Engelhardt <jengelh@medozas.de>,
Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>,
Patrick McHardy <kaber@trash.net>,
"netfilter-devel@vger.kernel.org"
<netfilter-devel@vger.kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"hans@schillstrom.com" <hans@schillstrom.com>
Subject: Re: [PATCH 1/1] netfilter: Add possibility to turn off netfilters defrag per netns
Date: Wed, 4 Jan 2012 18:23:41 +0100 [thread overview]
Message-ID: <20120104172341.GA3489@1984> (raw)
In-Reply-To: <201201041047.54579.hans.schillstrom@ericsson.com>
On Wed, Jan 04, 2012 at 10:47:53AM +0100, Hans Schillstrom wrote:
> On Wednesday 04 January 2012 10:32:14 Jan Engelhardt wrote:
> > On Wednesday 2012-01-04 10:03, Jozsef Kadlecsik wrote:
> >
> > >On Wed, 4 Jan 2012, Hans Schillstrom wrote:
> > >
> > >> On Wednesday 04 January 2012 09:28:05 Jozsef Kadlecsik wrote:
> > >> >
> > >> > On Wed, 4 Jan 2012, Hans Schillstrom wrote:
> > >> >
> > >> > > In some cases it not desirable to have auto defrag.
> > >> > > Ex. in a cluster where packets can arrive on different blades.
> > >> > > In that case it is possible to use containers (LXC) and send
> > >> > > all fragments to one place where defrag is enabled.
> > >> > >
> > >> > > This patch makes it possible to turn off the defrag per network name space,
> > >> > > by setting net.netfilter.nf_conntrack_nodefrag to 1.
> > >> > > Both IPv4 and IPv6 is effected by this sysctl.
> > >> > > Default is 0 which is defrag.
> > >> >
> > >> > Conntrack assumes that the packets are defragmented and will drop any
> > >> > unfragmented one. So your patch results packet drops.
> > >>
> > >> Hmmm, more work...
> > >> >
> > >> > Also, if you want to disable defragmentation then why don't you simply
> > >> > "mark" the packets with the NOTRACK target?
> > >>
> > >> I don't think that will work since NF_IP_PRI_CONNTRACK_DEFRAG is -400
> > >
> > >Then change NF_IP_PRI_RAW so that it precedes NF_IP_PRI_CONNTRACK_DEFRAG.
> > >The raw table should be made possible to completely override conntack and
> > >defrag is implicit part of the latter.
> >
> > We've been there (me in the thread even) - defrag is running before raw,
> > because otherwise you could not select packets based upon L4
> > parameters for non-defrag in the first place:
> >
> > -t raw ... -p udp --dport 53 -j CT --notrack
> >
> > Not that I overly care about whether defrag is before/after raw..
> >
> What about a mod param for ip{6}table_raw so it could be changed ?
No obscure modparam tweaks, please.
next prev parent reply other threads:[~2012-01-04 17:23 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-04 8:07 [PATCH 1/1] netfilter: Add possibility to turn off netfilters defrag per netns Hans Schillstrom
2012-01-04 8:28 ` Jozsef Kadlecsik
2012-01-04 8:49 ` Hans Schillstrom
2012-01-04 9:03 ` Jozsef Kadlecsik
2012-01-04 9:32 ` Jan Engelhardt
2012-01-04 9:47 ` Hans Schillstrom
2012-01-04 17:23 ` Pablo Neira Ayuso [this message]
2012-01-04 9:49 ` Jozsef Kadlecsik
2012-01-04 10:18 ` Hans Schillstrom
2012-01-04 11:17 ` Jan Engelhardt
2012-01-04 11:48 ` Hans Schillstrom
2012-01-04 17:40 ` Pablo Neira Ayuso
2012-01-04 18:05 ` Jozsef Kadlecsik
2012-01-04 20:56 ` Hans Schillstrom
2012-01-04 21:40 ` Jozsef Kadlecsik
2012-01-05 7:19 ` Hans Schillstrom
2012-01-05 9:11 ` Jozsef Kadlecsik
2012-01-05 14:18 ` Pablo Neira Ayuso
2012-01-09 8:58 ` Hans Schillstrom
2012-01-10 3:17 ` Pablo Neira Ayuso
2012-01-04 20:45 ` Hans Schillstrom
2012-01-04 21:15 ` Hans Schillstrom
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