From mboxrd@z Thu Jan 1 00:00:00 1970 From: Patrick McHardy Subject: Re: [PATCHv6 0/3] Interface group patches Date: Fri, 23 Nov 2007 01:10:24 +0100 Message-ID: <47461A70.2010201@trash.net> References: <200711221537.29396.wolfgang.walter@studentenwerk.mhn.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Cc: netfilter-devel@vger.kernel.org, linux-netdev@vger.kernel.org To: Wolfgang Walter Return-path: Received: from stinky.trash.net ([213.144.137.162]:49592 "EHLO stinky.trash.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751241AbXKWAK1 (ORCPT ); Thu, 22 Nov 2007 19:10:27 -0500 In-Reply-To: <200711221537.29396.wolfgang.walter@studentenwerk.mhn.de> Sender: netfilter-devel-owner@vger.kernel.org List-Id: netfilter-devel.vger.kernel.org Wolfgang Walter wrote: > From: Patrick McHardy >> I'm working on the incremental ruleset changing API BTW :) >> One of the changes will be that interface matching is not >> a default part of every rule, and without wildcards it will >> use the ifindex. But since the cost of this feature seems >> pretty low, I don't see a compelling reason against it. > > Using ifindex instead of string matching the interface name in -i and -o would > be a serious problem as it changes the semantics. > > 1) Now you can match a non existing interface. This is certainly used. I.e. > with vlan interfaces, ppp etc. > 2) Now your rule will match an interface even if the ifindex of the interface > changes. This is used (i.e. you activate a backup interface and rename it, > build new bridges etc.). > > If one wants to use the ifindex instead of a string match on the name one > should explicitly request that (i.e. by using "-i =eth0" or something like > that). Don't worry, it will subscribe to netdevice events and adjust the ifindex when necessary. For userspace its still a device name match.