From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH 1/2] IPV6: remove addresses and routes when carrier is lost Date: Tue, 03 Jun 2008 10:30:59 -0700 (PDT) Message-ID: <20080603.103059.193720094.davem@davemloft.net> References: <20080603102144.571df55b@extreme> <20080603.102501.193702820.davem@davemloft.net> <20080604.022836.31952523.yoshfuji@linux-ipv6.org> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: shemminger@vyatta.com, netdev@vger.kernel.org To: yoshfuji@linux-ipv6.org Return-path: Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:54032 "EHLO sunset.davemloft.net" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1755273AbYFCRbC (ORCPT ); Tue, 3 Jun 2008 13:31:02 -0400 In-Reply-To: <20080604.022836.31952523.yoshfuji@linux-ipv6.org> Sender: netdev-owner@vger.kernel.org List-ID: From: YOSHIFUJI Hideaki Date: Wed, 04 Jun 2008 02:28:36 +0900 (JST) > In article <20080603.102501.193702820.davem@davemloft.net> (at Tue, 03 Jun 2008 10:25:01 -0700 (PDT)), David Miller says: > > > From: Stephen Hemminger > > Date: Tue, 3 Jun 2008 10:21:44 -0700 > > > > > The patch just makes carrier_off respond the same as doing 'ip link set dev eth0 down' > > > (or ifconfig eth0 down). A router needs to be able to re-route when link fails. > > > > But I can't see how this behavior makes sense for the normal desktop case > > and it disagrees with existing practice for many years. > > > > If I pull out my network cable while making some adjustments in my > > rack, and then plug it back in, I don't expect to lose my static > > routes on that interface. > > > > That doesn't make any sense at all. > > How about ignoring routes via down interface? Look at what happens now in my example case. The packets simply get queued in the device queue until the carrier comes back up. Once it comes back up, the packets go out with zero packet loss. With your suggestion, the packets will get dropped if there are no other devices with active routes to the destination, which is a very poor quality of implementation decision in my opinion, especially for this case.