From patchwork Mon Apr 1 00:12:51 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Samuel Thibault X-Patchwork-Id: 232655 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id AFBC22C00CF for ; Mon, 1 Apr 2013 11:13:14 +1100 (EST) Received: from localhost ([::1]:49315 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UMSN6-0006XR-Mm for incoming@patchwork.ozlabs.org; Sun, 31 Mar 2013 20:13:12 -0400 Received: from eggs.gnu.org ([208.118.235.92]:48308) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UMSMr-0006X9-8B for qemu-devel@nongnu.org; Sun, 31 Mar 2013 20:12:59 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UMSMo-00073p-39 for qemu-devel@nongnu.org; Sun, 31 Mar 2013 20:12:57 -0400 Received: from toccata.ens-lyon.fr ([140.77.166.68]:42374 helo=toccata.ens-lyon.org) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UMSMn-00072t-Tb for qemu-devel@nongnu.org; Sun, 31 Mar 2013 20:12:54 -0400 Received: from localhost (localhost [127.0.0.1]) by toccata.ens-lyon.org (Postfix) with ESMTP id 07DFC84072; Mon, 1 Apr 2013 02:12:53 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at toccata.ens-lyon.org Received: from toccata.ens-lyon.org ([127.0.0.1]) by localhost (toccata.ens-lyon.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id n1GMgq7xRYPD; Mon, 1 Apr 2013 02:12:52 +0200 (CEST) Received: from type.ipv6 (youpi.is-a-geek.org [80.67.176.89]) (using TLSv1 with cipher DHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) by toccata.ens-lyon.org (Postfix) with ESMTPSA id A6D2384067; Mon, 1 Apr 2013 02:12:52 +0200 (CEST) Received: from samy by type.ipv6 with local (Exim 4.80) (envelope-from ) id 1UMSMl-0005ev-8o; Mon, 01 Apr 2013 02:12:51 +0200 Date: Mon, 1 Apr 2013 02:12:51 +0200 From: Samuel Thibault To: Stefan Hajnoczi Message-ID: <20130401001251.GD17794@type.youpi.perso.aquilenet.fr> Mail-Followup-To: Samuel Thibault , Stefan Hajnoczi , ped@listes.subiron.org, qemu-devel@nongnu.org References: <20130305163510.GC3177@type.bordeaux.inria.fr> <20130306122937.GD1954@stefanha-thinkpad.muc.redhat.com> <20130310200152.GY6036@type.youpi.perso.aquilenet.fr> <20130311083614.GA28434@stefanha-thinkpad.redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20130311083614.GA28434@stefanha-thinkpad.redhat.com> User-Agent: Mutt/1.5.21+34 (58baf7c9f32f) (2010-12-30) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.4.x-2.6.x [generic] X-Received-From: 140.77.166.68 Cc: ped@listes.subiron.org, qemu-devel@nongnu.org Subject: [Qemu-devel] [PATCH] Document mcast+ipv6 (Was: Re: socket, mcast looping back frames -> IPv6 broken) X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Stefan Hajnoczi, le Mon 11 Mar 2013 09:36:14 +0100, a écrit : > > Otherwise we may just document that one has to disable Duplicate Address > > Detection to get IPv6 working :/ > > Seems like this might be the only way for now. Here is a patch Samuel Document how to get IPv6 working with mcast socket Document that IPv6 can not work in mcast mode unless disabling DAD in the guest. Signed-off-by: Samuel Thibault diff --git a/qemu-options.hx b/qemu-options.hx index c40ba55..9074a24 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -1683,6 +1683,12 @@ mcast support is compatible with User Mode Linux (argument @option{eth@var{N}=mc @url{http://user-mode-linux.sf.net}. @item Use @option{fd=h} to specify an already opened UDP multicast socket. +@item +Since with multicast diffusion the guest will receive its own frames, its IPv6 +Duplicate Address Detection (DAD) will erroneously detect a duplicate, thus +preventing IPv6 from working. One has to disable DAD to get IPv6 working, for +instance on Linux by setting the sysctl @code{net.ipv6.conf.all.accept_dad} to +0. @end enumerate Example: