From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vlad Yasevich Subject: Re: [PATCH] macvlan: Set IFF_UNICAST_FLT flag to prevent unnecessary promisc mode. Date: Thu, 07 Mar 2013 15:43:43 -0500 Message-ID: <5138FBFF.9000108@redhat.com> References: <1362687708-8685-1-git-send-email-vyasevic@redhat.com> <5138F82F.6010005@candelatech.com> <5138F95A.9010305@redhat.com> Reply-To: vyasevic@redhat.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: Ben Greear Return-path: Received: from mx1.redhat.com ([209.132.183.28]:10309 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751200Ab3CGUnp (ORCPT ); Thu, 7 Mar 2013 15:43:45 -0500 In-Reply-To: <5138F95A.9010305@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: On 03/07/2013 03:32 PM, Vlad Yasevich wrote: > On 03/07/2013 03:27 PM, Ben Greear wrote: >> On 03/07/2013 12:21 PM, Vlad Yasevich wrote: >>> Macvlan already supports hw address filters. Set the IFF_UNICAST_FLT >>> so that it doesn't needlesly enter PROMISC mode when macvlans are >>> stacked. >> >> Out of curiosity, how can stacking mac-vlans be useful? >> >> (You are stacking more macvlans on a base mac-vlan?) > > Yep, and macvlans allows, but it looks like it only tries to detect a 2 > level stack. I am not sure what the reason is. Might be realated to > vlan-to-vlan communication. Aha. The reason is explained in this commit. commit b0832a2961022a076c812384435b5f0290b3fc91 Author: Eric Biederman Date: Fri Mar 13 13:15:37 2009 -0700 macvlan: Support creating macvlans from macvlans When running in a network namespace whose only link to the outside world is a macvlan device, not being able to create another macvlan is a real pain. So modify macvlan creation to allow automatically forward a creation of a macvlan on a macvlan to become a creation of a macvlan on the underlying network device. I don't know if it's useful to support more then 2 levels. -vlad > > -vlad > >> >> Thanks, >> Ben >> >