From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nicolas Dichtel Subject: Re: [PATCH RFC] ipv6: fix route selection if kernel is not compiled with CONFIG_IPV6_ROUTER_PREF Date: Wed, 10 Jul 2013 16:10:58 +0200 Message-ID: <51DD6B72.1050700@6wind.com> 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> <20130710132122.GD15411@order.stressinduktion.org> Reply-To: nicolas.dichtel@6wind.com Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: netdev@vger.kernel.org, yoshfuji@linux-ipv6.org, petrus.lt@gmail.com, davem@davemloft.net, hannes@stressinduktion.org To: unlisted-recipients:; (no To-header on input) Return-path: Received: from mail-wi0-f175.google.com ([209.85.212.175]:52510 "EHLO mail-wi0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752561Ab3GJOLD (ORCPT ); Wed, 10 Jul 2013 10:11:03 -0400 Received: by mail-wi0-f175.google.com with SMTP id m6so11439772wiv.14 for ; Wed, 10 Jul 2013 07:11:01 -0700 (PDT) In-Reply-To: <20130710132122.GD15411@order.stressinduktion.org> Sender: netdev-owner@vger.kernel.org List-ID: Le 10/07/2013 15:21, Hannes Frederic Sowa a =C3=A9crit : > 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 = the >>>>>> 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_nsibli= ngs >>> counter in this condition: >>> >>> /* If we have the same destination and the= same >>> metric, >>> * but not the same gateway, then the rout= e we >>> try to >>> * add is sibling to this route, increment= our >>> counter >>> * of siblings, and later we will add our = route >>> to the >>> * list. >>> * Only static routes (which don't have fl= ag >>> * RTF_EXPIRES) are used for ECMPv6. >>> * >>> * To avoid long list, we only had sibling= s 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 gatewa= y >>> 2001:db8::32, siblings 2, metric 0, expires 0 gateway 2 idev6 >>> ffff8801139ddc00 dev ffff880117e83000 >>> [ 42.505912] (rt): ffff88011796d800 dst 2000::1 plen 128 gateway >>> fe80::5054:ff:fe82:e153, siblings 1, metric 0, expires 0 gateway 2 = idev6 >>> ffff880117edc400 dev ffff8801185cb000 >>> [ 42.527241] (iter): ffff88011796d380 dst 2000::1 plen 128 gatewa= y >>> 2001:db8::33, siblings 2, metric 0, expires 0 gateway 2 idev6 >>> ffff8801139ddc00 dev ffff880117e83000 >>> [ 42.536440] (rt): ffff88011796d800 dst 2000::1 plen 128 gateway >>> fe80::5054:ff:fe82:e153, siblings 2, metric 0, expires 0 gateway 2 = idev6 >>> ffff880117edc400 dev ffff8801185cb000 >>> >>> From my understanding these two routes should not be aggregated in= one >>> ecmp >>> route set. Am I seeing this correct? (My configuration is like in t= he mail >>> before.) >> Hmm, why? >> Routes have the same destination, same metric, are static (expires =3D= =3D 0) >> and have a gateway. > > The route with rt6i_gateway does actually expire because I got it fro= m > autoconf and ip -6 r l confirms this, too. It seems this is only the = cached > route (I will confirm shortly). Is this still ok? I wonder why expires is 0. Even if this route is cached, the flag RTF_E= XPIRES=20 should be set. Am I wrong? Nicolas