From mboxrd@z Thu Jan 1 00:00:00 1970 From: Patrick McHardy Subject: Re: netfilter: marking IPv6 packets sends them to the wrong interface Date: Mon, 24 Jan 2011 17:10:50 +0100 Message-ID: <4D3DA48A.2020605@trash.net> References: <20110123122108.GA30305@darkside.kls.lan> <4D3D82D1.6050305@trash.net> <20110124143518.GA2616@darkside.kls.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit To: Mario 'BitKoenig' Holbe , netfilter-devel@vger.kernel.org, linux-kernel@vger.kernel.org, NetDev Return-path: Received: from stinky.trash.net ([213.144.137.162]:33042 "EHLO stinky.trash.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753357Ab1AXQLG (ORCPT ); Mon, 24 Jan 2011 11:11:06 -0500 In-Reply-To: <20110124143518.GA2616@darkside.kls.lan> Sender: netfilter-devel-owner@vger.kernel.org List-ID: Am 24.01.2011 15:35, schrieb Mario 'BitKoenig' Holbe: > On Mon, Jan 24, 2011 at 02:46:57PM +0100, Patrick McHardy wrote: >> On 23.01.2011 13:21, Mario 'BitKoenig' Holbe wrote: >>> Without marking everything runs as it should be. >>> Marking eth0 packets results in all advertisements transmitted via eth1. >>> The behaviour goes back to normal as soon as the marking disappears. >>> I also tried marking with 0xff00 instead of 1 - same results. >> That probably means that we're not using the correct keys >> when rerouting in ip6_route_me_harder(). Just for testing, >> please try to disable the ip6_route_me_harder() call in >> net/ipv6/netfilter/ip6table_mangle.c::ip6t_mangle_out(). > > Yes, disabling the ip6_route_me_harder() call in ip6t_mangle_out() > results in the advertisements being transmitted on the correct > interfaces Thanks. The problem appears to be that ip6_route_me_harder() only uses the socket's oif for the route lookup when the socket is bound to an interface, but radvd uses IPV6_PKTINFO to specify the outgoing interface. I guess netfilter shouldn't be overriding IPV6_PKTINFO, but we unfortunately have neither an indication of this nor the original route lookup keys available at the time the packet is rerouted.