From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pablo Neira Ayuso Subject: Re: [PATCH 1/1] netfilter: Add possibility to turn off netfilters defrag per netns Date: Wed, 4 Jan 2012 18:23:41 +0100 Message-ID: <20120104172341.GA3489@1984> References: <1325664443-10320-1-git-send-email-hans.schillstrom@ericsson.com> <201201041047.54579.hans.schillstrom@ericsson.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Jan Engelhardt , Jozsef Kadlecsik , Patrick McHardy , "netfilter-devel@vger.kernel.org" , "netdev@vger.kernel.org" , "hans@schillstrom.com" To: Hans Schillstrom Return-path: Content-Disposition: inline In-Reply-To: <201201041047.54579.hans.schillstrom@ericsson.com> Sender: netdev-owner@vger.kernel.org List-Id: netfilter-devel.vger.kernel.org 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.