From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Frederic Sowa Subject: Re: [PATCH RFC] ipv6: fix route selection if kernel is not compiled with CONFIG_IPV6_ROUTER_PREF Date: Wed, 10 Jul 2013 15:21:22 +0200 Message-ID: <20130710132122.GD15411@order.stressinduktion.org> References: <20130707173031.GC9625@order.stressinduktion.org> <20130709215701.GD9763@order.stressinduktion.org> <51DD1352.8000705@6wind.com> <51DD2959.9060206@6wind.com> <20130710105316.GA5735@order.stressinduktion.org> <51DD521F.1000905@6wind.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: netdev@vger.kernel.org, yoshfuji@linux-ipv6.org, petrus.lt@gmail.com, davem@davemloft.net To: Nicolas Dichtel Return-path: Received: from s15338416.onlinehome-server.info ([87.106.68.36]:36836 "EHLO order.stressinduktion.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753834Ab3GJNVX (ORCPT ); Wed, 10 Jul 2013 09:21:23 -0400 Content-Disposition: inline In-Reply-To: <51DD521F.1000905@6wind.com> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, Jul 10, 2013 at 02:22:55PM +0200, Nicolas Dichtel wrote: > Le 10/07/2013 12:53, Hannes Frederic Sowa a =C3=A9crit : > >On Wed, Jul 10, 2013 at 11:28:57AM +0200, Nicolas Dichtel wrote: > >>Le 10/07/2013 09:54, Nicolas Dichtel a =C3=A9crit : > >>>Le 09/07/2013 23:57, Hannes Frederic Sowa a =C3=A9crit : > >>>>After starting a ping6 2000::1 the box should panic soon, after t= he > >>>>first nexthop entry times out. > >>>> > >>>>Perhaps you could give me a hint? > >>>I will run some tests with your patch. Will see. > >>I don't reproduce this panic. > > > >I just dumped the routes for which it does increase the rt6i_nsiblin= gs > >counter in this condition: > > > > /* If we have the same destination and the = same=20 > > metric, > > * but not the same gateway, then the route= we=20 > > try to > > * add is sibling to this route, increment = our=20 > > counter > > * of siblings, and later we will add our r= oute=20 > > to the > > * list. > > * Only static routes (which don't have fla= g > > * RTF_EXPIRES) are used for ECMPv6. > > * > > * To avoid long list, we only had siblings= if the > > * route have a gateway. > > */ > > if (rt->rt6i_flags & RTF_GATEWAY && > > !(rt->rt6i_flags & RTF_EXPIRES) && > > !(iter->rt6i_flags & RTF_EXPIRES)) > > rt->rt6i_nsiblings++; > > dump_route(iter, "(iter)"); > > dump_route(rt, "(rt)"); > > } > > > > > > > >Here: > > > >[ 42.497470] (iter): ffff88011796cc00 dst 2000::1 plen 128 gateway= =20 > >2001:db8::32, siblings 2, metric 0, expires 0 gateway 2 idev6=20 > >ffff8801139ddc00 dev ffff880117e83000 > >[ 42.505912] (rt): ffff88011796d800 dst 2000::1 plen 128 gateway=20 > >fe80::5054:ff:fe82:e153, siblings 1, metric 0, expires 0 gateway 2 i= dev6=20 > >ffff880117edc400 dev ffff8801185cb000 > >[ 42.527241] (iter): ffff88011796d380 dst 2000::1 plen 128 gateway= =20 > >2001:db8::33, siblings 2, metric 0, expires 0 gateway 2 idev6=20 > >ffff8801139ddc00 dev ffff880117e83000 > >[ 42.536440] (rt): ffff88011796d800 dst 2000::1 plen 128 gateway=20 > >fe80::5054:ff:fe82:e153, siblings 2, metric 0, expires 0 gateway 2 i= dev6=20 > >ffff880117edc400 dev ffff8801185cb000 > > > > From my understanding these two routes should not be aggregated in = one=20 > > ecmp > >route set. Am I seeing this correct? (My configuration is like in th= e mail > >before.) > Hmm, why? > Routes have the same destination, same metric, are static (expires =3D= =3D 0)=20 > and have a gateway. The route with rt6i_gateway does actually expire because I got it from autoconf and ip -6 r l confirms this, too. It seems this is only the ca= ched route (I will confirm shortly). Is this still ok? > nsiblings counts the number of siblings and does not contains ourself= ,=20 > hence both iter should be 1, not 2. Ok. Thanks for helping, Hannes