From mboxrd@z Thu Jan 1 00:00:00 1970 From: Toshiaki Makita Subject: Re: [PATCH v3 net 2/9] bridge: Fix the way to insert new local fdb entries in br_fdb_changeaddr Date: Sat, 08 Feb 2014 11:43:48 +0900 Message-ID: <1391827428.1739.22.camel@localhost.localdomain> References: <1391759306-24956-1-git-send-email-makita.toshiaki@lab.ntt.co.jp> <1391759306-24956-3-git-send-email-makita.toshiaki@lab.ntt.co.jp> <20140207093127.56f78187@samsung-9> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Toshiaki Makita , "David S . Miller" , Vlad Yasevich , netdev@vger.kernel.org To: Stephen Hemminger Return-path: Received: from mail-pa0-f41.google.com ([209.85.220.41]:35318 "EHLO mail-pa0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750756AbaBHCny (ORCPT ); Fri, 7 Feb 2014 21:43:54 -0500 Received: by mail-pa0-f41.google.com with SMTP id fa1so3964726pad.28 for ; Fri, 07 Feb 2014 18:43:53 -0800 (PST) In-Reply-To: <20140207093127.56f78187@samsung-9> Sender: netdev-owner@vger.kernel.org List-ID: On Fri, 2014-02-07 at 09:31 -0700, Stephen Hemminger wrote: > On Fri, 7 Feb 2014 16:48:19 +0900 > Toshiaki Makita wrote: > > > Since commit bc9a25d21ef8 ("bridge: Add vlan support for local fdb entries"), > > br_fdb_changeaddr() has inserted a new local fdb entry only if it can > > find old one. But if we have two ports where they have the same address > > or user has deleted a local entry, there will be no entry for one of the > > ports. > > > > Example of problematic case: > > ip link set eth0 address aa:bb:cc:dd:ee:ff > > ip link set eth1 address aa:bb:cc:dd:ee:ff > > brctl addif br0 eth0 > > brctl addif br0 eth1 # eth1 will not have a local entry due to dup. > > I think the second addif should fail, it doesn't seem valid to have > two interfaces on same bridge with same address. Most hardware switches > would disable the port in that case. Thank you for your comment, but I don't think so for several reasons. - From other network elements on the same network, bridge ports don't appear to have a mac address, but the bridge appears to have several mac addresses that can reach to the bridge. The duplicated address is simply seen as one of those addresses. I don't think it is a problem. - This operation (add a port that has duplicated address) has allowed for several years, and it is obviously intended, as commented in fdb_insert(). 417 /* it is okay to have multiple ports with same 418 * address, just use the first one. 419 */ - Hardware switches usually have one mac address per one switch. Their ports don't have mac addresses. It is not reasonable to compare hardware switches. Thanks, Toshiaki Makita