From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chr Subject: Re: IPv6 unique local address flushes on up/down Date: Tue, 25 Mar 2008 17:07:52 +0100 Message-ID: <200803251707.52528.chunkeey@web.de> References: <200803251557.21563.chunkeey@web.de> <20080326.002428.19095257.yoshfuji@linux-ipv6.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: hostap@lists.shmoo.com, netdev@vger.kernel.org, chunkeey@web.de To: YOSHIFUJI Hideaki / =?utf-8?q?=E5=90=89=E8=97=A4=E8=8B=B1=E6=98=8E?= Return-path: Received: from fmmailgate02.web.de ([217.72.192.227]:57059 "EHLO fmmailgate02.web.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755472AbYCYQH5 convert rfc822-to-8bit (ORCPT ); Tue, 25 Mar 2008 12:07:57 -0400 In-Reply-To: <20080326.002428.19095257.yoshfuji@linux-ipv6.org> Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-ID: On Tuesday 25 March 2008 16:24:28 YOSHIFUJI Hideaki / =E5=90=89=E8=97=A4= =E8=8B=B1=E6=98=8E wrote: > In article <200803251557.21563.chunkeey@web.de> (at Tue, 25 Mar 2008=20 15:57:21 +0100), Chr says: > > Now my question, which _one_ should we fix the applications or the > > stack?! I think the network stack, but I don't know if there are RF= C > > about this issue... or is there already some flag/setting which I'v= e > > missed so far? > > Well..., in fact, this is known as an uneasy-to-fix issue. > The behavior han not been changed for long time, so you definately > need to have work-around for this issue, anyway. > > From specification point of view, we need to re-perform DAD (duplicat= e > address detection) after down-up cycle or even link-down and up. > One possible way is to add "tentative" flag for static addresses > (instead of purging them) when the interface is going down and > reperform DAD for all of such addresses when the interface is coming = up. > If the link is being down, we might want to use "Optimistic" DAD inst= ead. > Ah yeah, ok... I guess... alright! ...=20 but another question, about this issue form the userspace side. Since I'm going to use the stateful DHCPv6 way... I'm wondering how I c= an set=20 the tentative flag from userspace? Because the DHCPv6 Client uses the ip utility to add the ipv6 address t= oo. And unlike the _static_ setting for the router, this _stateful_=20 autoconf-address should be flushed on ifup/down, right?=20 And according to the manual page of my iproute (debian sid - from 2008-= 01-08).=20 the ip utility doesn't have this "set flag xy for address zw" capabilit= y at=20 all...=20 so how can I _possibly_ set it, or prevent from being set?=20 Or do I miss some good and obvious point here again?!=20 Regards, Christian