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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7CE62C4332F for ; Fri, 18 Nov 2022 11:46:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235322AbiKRLqs (ORCPT ); Fri, 18 Nov 2022 06:46:48 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45252 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230042AbiKRLqr (ORCPT ); Fri, 18 Nov 2022 06:46:47 -0500 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [IPv6:2a0a:51c0:0:237:300::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 478F512AF1 for ; Fri, 18 Nov 2022 03:46:46 -0800 (PST) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1ovzpT-00027X-Cy; Fri, 18 Nov 2022 12:46:43 +0100 Date: Fri, 18 Nov 2022 12:46:43 +0100 From: Florian Westphal To: Phil Sutter , Pablo Neira Ayuso , Florian Westphal , netfilter-devel@vger.kernel.org Subject: Re: [nft PATCH v2 0/4] xt: Implement dump and restore support Message-ID: <20221118114643.GD15714@breakpoint.cc> References: <20221117174546.21715-1-phil@nwl.cc> <20221117211347.GB15714@breakpoint.cc> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org Phil Sutter wrote: > On Fri, Nov 18, 2022 at 11:11:42AM +0100, Pablo Neira Ayuso wrote: > > Merging threads. > > > > On Fri, Nov 18, 2022 at 10:55:04AM +0100, Phil Sutter wrote: > > [...] > > > > I think this more or less a summary of what we discussed in the NFWS. > > > > > > Pablo, I think you're mixing up two things here: > > > > > > This "support dump and load of compat expression" feature is to sanitize > > > the current situation with up to date iptables and nftables. > > > > OK, then the problem we discuss is mixing iptables-nft and nftables. > > > > On Fri, Nov 18, 2022 at 10:47:48AM +0100, Phil Sutter wrote: > > [...] > > > > At this time I'd rather like a time machine to prevent nft_compat.c from > > > > getting merged :-( > > > > > > If you do, please convince Pablo to not push iptables commit 384958620a. > > > I think it opened the can of worms we're trying to confine here. > > > > It could be worst, if iptables-nft would not be in place, then old > > iptables-legacy and new nftables rules would have no visibility each > > other. > > > > With iptables-nft we have a way to move forward: > > > > - Replace nft_compat by native expressions from iptables-nft. > > - Extend iptables-nft to understand more complex expressions, worst > > case dump a native representation. > > > > Why don't we just move ahead this path instead of spinning around the > > compat layer? This only requires userspace updates on iptables-nft. > > Sure! I'm just picking low hanging fruits first. With even translation > support being still incomplete, I fear it will take a while until the > tools are fluent enough for this to not matter anymore. And then there's > still nftables without libxtables support. Then perhaps its better to do following path: 1. Try ->xlate(), if that fails, then print a 'breaking' format? As far as I understand the problem is the "# comment" - type syntax that makes nft just skip the incomplete rule, so perhaps just use invalid format? Example: counter packets 0 bytes 0 # name foo interval 250.0ms ewmalog 500.0ms Instead make this something like counter packets 0 bytes 0 nft_compat [ RATEEST name foo interval 250.0ms ewmalog 500.0ms ] # unsupported iptables-nft rule ? I'd like to avoid exposure in the frontend with compatible-restore-approach if possible.