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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 48E6AC433F5 for ; Tue, 19 Oct 2021 14:47:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2F2AE60EBB for ; Tue, 19 Oct 2021 14:47:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233052AbhJSOtn convert rfc822-to-8bit (ORCPT ); Tue, 19 Oct 2021 10:49:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40094 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231848AbhJSOtf (ORCPT ); Tue, 19 Oct 2021 10:49:35 -0400 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [IPv6:2a0a:51c0:0:12e:520::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BCC9BC0617B1; Tue, 19 Oct 2021 07:46:25 -0700 (PDT) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1mcqNj-0005NP-7M; Tue, 19 Oct 2021 16:46:23 +0200 Date: Tue, 19 Oct 2021 16:46:23 +0200 From: Florian Westphal To: David Ahern Cc: Florian Westphal , Eugene Crosser , netdev@vger.kernel.org, netfilter-devel@vger.kernel.org, Lahav Schlesinger , David Ahern Subject: Re: Commit 09e856d54bda5f288ef8437a90ab2b9b3eab83d1r "vrf: Reset skb conntrack connection on VRF rcv" breaks expected netfilter behaviour Message-ID: <20211019144623.GG28644@breakpoint.cc> References: <20211013092235.GA32450@breakpoint.cc> <20211015210448.GA5069@breakpoint.cc> <378ca299-4474-7e9a-3d36-2350c8c98995@gmail.com> <20211018143430.GB28644@breakpoint.cc> <20211019114939.GD28644@breakpoint.cc> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: 8BIT In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org David Ahern wrote: > On 10/19/21 5:49 AM, Florian Westphal wrote: > > David Ahern wrote: > >> Thanks for the detailed summary and possible solutions. > >> > >> NAT/MASQ rules with VRF were not really thought about during > >> development; it was not a use case (or use cases) Cumulus or other NOS > >> vendors cared about. Community users were popping up fairly early and > >> patches would get sent, but no real thought about how to handle both > >> sets of rules - VRF device and port devices. > >> > >> What about adding an attribute on the VRF device to declare which side > >> to take -- rules against the port device or rules against the VRF device > >> and control the nf resets based on it? > > > > This would need a way to suppress the NF_HOOK invocation from the > > normal IP path. Any idea on how to do that? AFAICS there is no way to > > get to the vrf device at that point, so no way to detect the toggle. > > > > Or did you mean to only suppress the 2nd conntrack round? > > My thought was that the newly inserted nf_reset_ct fixed one use case > and breaks another, so the new attribute would control that call. Right, but the 'new nf_reset_ct' are there to undo the 2nd nat transformation done on round 2. So, no round 2, no second nat transformation & no need for the new nf_ct_reset(). I dislike the idea of treating locally originating flows different from forwarded ones. Treating them the same causes asymmetry of ingress&egress, i.e. ingress means 'traverse conntrack for lower device' whereas egress means 'traverse conntrack via vrf device'. I could hack the nat core & the conntrack commit hook to skip functionality if the outdev is a vrf device -- that should in theory result in consistent semantics, i.e. conntrack only runs in lower device context. I'll give that a shot unless someone has a better idea.