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 439F2C433EF for ; Thu, 30 Sep 2021 07:19:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 204B161882 for ; Thu, 30 Sep 2021 07:19:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348645AbhI3HVN (ORCPT ); Thu, 30 Sep 2021 03:21:13 -0400 Received: from mail.netfilter.org ([217.70.188.207]:35894 "EHLO mail.netfilter.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348624AbhI3HVL (ORCPT ); Thu, 30 Sep 2021 03:21:11 -0400 Received: from netfilter.org (unknown [78.30.35.141]) by mail.netfilter.org (Postfix) with ESMTPSA id 251CA63EB3; Thu, 30 Sep 2021 09:18:03 +0200 (CEST) Date: Thu, 30 Sep 2021 09:19:24 +0200 From: Pablo Neira Ayuso To: Daniel Borkmann Cc: netfilter-devel@vger.kernel.org, davem@davemloft.net, netdev@vger.kernel.org, kuba@kernel.org, lukas@wunner.de, kadlec@netfilter.org, fw@strlen.de, ast@kernel.org, edumazet@google.com, tgraf@suug.ch, nevola@gmail.com, john.fastabend@gmail.com, willemb@google.com Subject: Re: [PATCH nf-next v5 0/6] Netfilter egress hook Message-ID: References: <20210928095538.114207-1-pablo@netfilter.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, Sep 30, 2021 at 08:08:53AM +0200, Daniel Borkmann wrote: > On 9/28/21 11:55 AM, Pablo Neira Ayuso wrote: > > Hi, > > > > This patchset v5 that re-adds the Netfilter egress: > > > > 1) Rename linux/netfilter_ingress.h to linux/netfilter_netdev.h > > from Lukas Wunner. > > > > 2) Generalize ingress hook file to accomodate egress support, > > from Lukas Wunner. > > > > 3) Modularize Netfilter ingress hook into nf_tables_netdev: Daniel > > Borkmann is requesting for a mechanism to allow to blacklist > > Netfilter, this allows users to blacklist this new module that > > includes ingress chain and the new egress chain for the netdev > > family. There is no other in-tree user of the ingress and egress > > hooks than this which might interfer with his matter. > > > > 4) Place the egress hook again before the tc egress hook as requested > > by Daniel Borkmann. Patch to add egress hook from Lukas Wunner. > > The Netfilter egress hook remains behind the static key, if unused > > performance degradation is negligible. > > > > 5) Add netfilter egress handling to af_packet. > > > > Arguably, distributors might decide to compile nf_tables_netdev > > built-in. Traditionally, distributors have compiled their kernels using > > the default configuration that Netfilter Kconfig provides (ie. use > > modules whenever possible). In any case, I consider that distributor > > policy is out of scope in this discussion, providing a mechanism to > > allow Daniel to prevent Netfilter ingress and egress chains to be loaded > > should be sufficient IMHO. > > Hm, so in the case of SRv6 users were running into a similar issue and commit > 7a3f5b0de364 ("netfilter: add netfilter hooks to SRv6 data plane") [0] added > a new hook along with a sysctl which defaults the new hook to off. > > The rationale for it was given as "the hooks are enabled via nf_hooks_lwtunnel > sysctl to make sure existing netfilter rulesets do not break." [0,1] > > If the suggestion to flag the skb [2] one way or another from the tc forwarding > path (e.g. skb bit or per-cpu marker) is not technically feasible, then why not > do a sysctl toggle like in the SRv6 case? I am already providing a global toggle to disable netdev ingress/egress hooks? In the SRv6 case that is not possible. Why do you need you need a sysctl knob when my proposal is already addressing your needs?