From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: [PATCH 1/2] bridge: leave carrier on for empty bridge Date: Sat, 3 Sep 2011 21:14:38 -0700 Message-ID: <20110903211438.2a43d2f2@nehalam.ftrdhcpuser.net> References: <20110902172220.830228928@vyatta.com> <20110902172247.396753508@vyatta.com> <4E614CF7.7030700@gmail.com> <20110902151100.327af0bf@nehalam.ftrdhcpuser.net> <4E6272BC.4020707@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: "David S. Miller" , netdev@vger.kernel.org To: Nicolas de =?ISO-8859-1?B?UGVzbG/8YW4=?= Return-path: Received: from mail.vyatta.com ([76.74.103.46]:41762 "EHLO mail.vyatta.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750793Ab1IDEO2 convert rfc822-to-8bit (ORCPT ); Sun, 4 Sep 2011 00:14:28 -0400 In-Reply-To: <4E6272BC.4020707@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: On Sat, 03 Sep 2011 20:32:28 +0200 Nicolas de Peslo=FCan wrote: > Le 03/09/2011 00:11, Stephen Hemminger a =E9crit : > > On Fri, 02 Sep 2011 23:39:03 +0200 > > Nicolas de Peslo=FCan wrote: > > > >> Le 02/09/2011 19:22, Stephen Hemminger a =E9crit : > >>> This resolves a regression seen by some users of bridging. > >>> Some users use the bridge like a dummy device. > >>> They expect to be able to put an IPv6 address on the device > >>> with no ports attached during boot. > >>> > >>> Note: the bridge still will reflect the state of ports in the > >>> bridge if there are any added. > >> > >> Doesn't this jeopardize the behavior introduced in 1faa4356a3bd89e= a11fb92752d897cff3a20ec0e > >> "bridge: control carrier based on ports online"? > >> > >> If the user starts the DHCP client before adding the first port to= the bridge, the DHCP client will > >> have a carrier and start the autoconfiguration process. This was t= he old behavior, but you fixed it. > >> > >> Nicolas. > >> > > > > There is no perfect solution. > > If DHCP works then IPv6 breaks? >=20 > Instead of asserting carrier when the bridge have no port, can't we a= ssert carrier when the three=20 > following condition are true at the same time : >=20 > - The bridge have no port. > - At least one IP address is setup on the bridge. > - The two above conditions are true for more than a configurable amou= nt of seconds, with a default=20 > of 10, for example. >=20 > This would only delay carrier on for a few seconds for the regression= and keep the current behavior=20 > (carrier off until at least 1 port is on) for DHCP. This fails on two counts: 1. Bridge's often run without IP addresses! 2. DHCP won't try and send out request until carrier is true.