From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Frederic Sowa Subject: Re: [PATCH net-next] ipv6: addrconf: fix mcast route for GRE devices Date: Wed, 30 Jul 2014 17:14:42 +0200 Message-ID: <1406733282.5122.12.camel@localhost> References: <1406681743-104844-1-git-send-email-equinox@diac24.net> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: "David S. Miller" , netdev@vger.kernel.org, Stephen Hemminger To: David Lamparter Return-path: Received: from out2-smtp.messagingengine.com ([66.111.4.26]:59284 "EHLO out2-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753151AbaG3POq (ORCPT ); Wed, 30 Jul 2014 11:14:46 -0400 Received: from compute5.internal (compute5.nyi.internal [10.202.2.45]) by gateway1.nyi.internal (Postfix) with ESMTP id B68602397B for ; Wed, 30 Jul 2014 11:14:44 -0400 (EDT) In-Reply-To: <1406681743-104844-1-git-send-email-equinox@diac24.net> Sender: netdev-owner@vger.kernel.org List-ID: Hi, On Mi, 2014-07-30 at 02:55 +0200, David Lamparter wrote: > GRE devices, for some reason, were coming up with an autoconfigured > address, but no ff00::/8 route in the local table. This breaks any kind > of multicast, in particular OSPFv3, mDNS, - and ND. In fact, IPv6 only > works at all because there is little need for ND on PtP devices. > > Adding any other IPv6 address on the device would rectify this issue > through inet6_addr_add()/addrconf_add_dev() - and would leave the route > around even if the address was later removed. (This is probably why > this issue was not discovered earlier. AFAICS it has been there from > the beginning, e.g. aee80b5 "generate link local address for GRE > tunnel") Yep, this is poor, but changing this will break user space... > (Note: multicast is supported on GRE devices of all kinds, including PtP > GRE, P-t-Mcast GRE and NBMA-GRE.) > > Fixes: aee80b54b235 (ipv6: generate link local address for GRE tunnel) > Signed-off-by: David Lamparter > Cc: Stephen Hemminger We should install routes before joining LL, I would go with idev = addrconf_add_dev(dev); if (IS_ERR(idev)) return; in addrconf_gre_config etc. Looks like we don't correctly configure ARPHRD_IP6GRE gre tunnels... > --- > net/ipv6/addrconf.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c > index 0b239fc..655a0df 100644 > --- a/net/ipv6/addrconf.c > +++ b/net/ipv6/addrconf.c > @@ -2824,6 +2824,7 @@ static void addrconf_gre_config(struct net_device *dev) > } > > addrconf_addr_gen(idev, true); > + addrconf_add_mroute(dev); > } > #endif > Thanks, Hannes