From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B187FC63777 for ; Mon, 16 Nov 2020 22:31:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 62AD22080A for ; Mon, 16 Nov 2020 22:31:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730280AbgKPWbU (ORCPT ); Mon, 16 Nov 2020 17:31:20 -0500 Received: from correo.us.es ([193.147.175.20]:50952 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729756AbgKPWbT (ORCPT ); Mon, 16 Nov 2020 17:31:19 -0500 Received: from antivirus1-rhel7.int (unknown [192.168.2.11]) by mail.us.es (Postfix) with ESMTP id 31250DED2D for ; Mon, 16 Nov 2020 23:31:17 +0100 (CET) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 1B77DDA78F for ; Mon, 16 Nov 2020 23:31:17 +0100 (CET) Received: by antivirus1-rhel7.int (Postfix, from userid 99) id 0F91ADA789; Mon, 16 Nov 2020 23:31:17 +0100 (CET) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id D12E3DA72F; Mon, 16 Nov 2020 23:31:14 +0100 (CET) Received: from 192.168.1.97 (192.168.1.97) by antivirus1-rhel7.int (F-Secure/fsigk_smtp/550/antivirus1-rhel7.int); Mon, 16 Nov 2020 23:31:14 +0100 (CET) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/antivirus1-rhel7.int) Received: from us.es (unknown [90.77.255.23]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: 1984lsi) by entrada.int (Postfix) with ESMTPSA id B3FE14265A5A; Mon, 16 Nov 2020 23:31:14 +0100 (CET) Date: Mon, 16 Nov 2020 23:31:14 +0100 X-SMTPAUTHUS: auth mail.us.es From: Pablo Neira Ayuso To: Tobias Waldekranz Cc: Jakub Kicinski , netfilter-devel@vger.kernel.org, davem@davemloft.net, netdev@vger.kernel.org, razor@blackwall.org, jeremy@azazel.net Subject: Re: [PATCH net-next,v3 0/9] netfilter: flowtable bridge and vlan enhancements Message-ID: <20201116223114.GA6905@salvia> References: <20201111193737.1793-1-pablo@netfilter.org> <20201113175556.25e57856@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> <20201114115906.GA21025@salvia> <87sg9cjaxo.fsf@waldekranz.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <87sg9cjaxo.fsf@waldekranz.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-Virus-Scanned: ClamAV using ClamSMTP Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org On Sat, Nov 14, 2020 at 03:00:03PM +0100, Tobias Waldekranz wrote: > On Sat, Nov 14, 2020 at 12:59, Pablo Neira Ayuso wrote: > > If any of the flowtable device goes down / removed, the entries are > > removed from the flowtable. This means packets of existing flows are > > pushed up back to classic bridge / forwarding path to re-evaluate the > > fast path. > > > > For each new flow, the fast path that is selected freshly, so they use > > the up-to-date FDB to select a new bridge port. > > > > Existing flows still follow the old path. The same happens with FIB > > currently. > > > > It should be possible to explore purging entries in the flowtable that > > are stale due to changes in the topology (either in FDB or FIB). > > > > What scenario do you have specifically in mind? Something like VM > > migrates from one bridge port to another? > > This should work in the case when the bridge ports are normal NICs or > switchdev ports, right? Yes. > In that case, relying on link state is brittle as you can easily have a > switch or a media converter between the bridge and the end-station: > > br0 br0 > / \ / \ > eth0 eth1 eth0 eth1 > / \ => / \ > [sw0] [sw1] [sw0] [sw1] > / \ / \ > A A > > In a scenario like this, A has clearly moved. But neither eth0 nor eth1 > has seen any changes in link state. > > This particular example is a bit contrived. But this is essentially what > happens in redundant topologies when reconfigurations occur (e.g. STP). > > These protocols will typically signal reconfigurations to all bridges > though, so as long as the affected flows are flushed at the same time as > the FDB it should work. Yes, watching the FDB should allow to clean up stale flows immediately.