From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maxime Bizon Subject: Re: 3.6 routing cache regression, multicast loopback broken Date: Thu, 22 Nov 2012 15:04:16 +0100 Message-ID: <1353593056.8285.24.camel@sakura.staff.proxad.net> References: <1352133471.12029.43.camel@sakura.staff.proxad.net> Reply-To: mbizon@freebox.fr Mime-Version: 1.0 Content-Type: text/plain; charset="ANSI_X3.4-1968" Content-Transfer-Encoding: 7bit Cc: David Miller , netdev@vger.kernel.org To: Julian Anastasov Return-path: Received: from ns.iliad.fr ([212.27.33.1]:38095 "EHLO ns.iliad.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756915Ab2KVT2b (ORCPT ); Thu, 22 Nov 2012 14:28:31 -0500 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Wed, 2012-11-21 at 02:35 +0200, Julian Anastasov wrote: Hi, > Do you also have CONFIG_IP_MROUTE enabled? I see the I don't > problem with caching both "RTCF_MULTICAST | RTCF_LOCAL" and > "RTCF_MULTICAST" flags to same place but I'm not sure in the > sequence of route lookups for your setup. ip_mc_output does > not care about RTCF_LOCAL when CONFIG_IP_MROUTE is disabled, > so in this case it should loop the packet even on wrong > caching (without RTCF_LOCAL flag). but the problem here was that dst was using ip_output() instead of ip_mc_output(). > Can you try the following patch. If it does not > solve the problem we have to add some debugs in __mkroute_output. > And I'm not sure if this is fatal only when CONFIG_IP_MROUTE > is enabled, I have to spend more time to check the code. > As an optimization, the patch avoids lookup for fnhe > when multicast is not cached because multicasts are > not redirected and they do not learn PMTU. > > The patch is not tested. I'll update the commit > message after your tests. the patch fixes the problem, and it looks valid to me. thanks ! -- Maxime