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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, 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 5B810C43331 for ; Tue, 31 Mar 2020 01:33:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2B2AD2072A for ; Tue, 31 Mar 2020 01:33:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=permerror (0-bit key) header.d=uniroma2.it header.i=@uniroma2.it header.b="Gmmobyge"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=uniroma2.it header.i=@uniroma2.it header.b="RFNKoRW/" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729373AbgCaBdY (ORCPT ); Mon, 30 Mar 2020 21:33:24 -0400 Received: from smtp.uniroma2.it ([160.80.6.16]:46587 "EHLO smtp.uniroma2.it" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729372AbgCaBdY (ORCPT ); Mon, 30 Mar 2020 21:33:24 -0400 Received: from smtpauth-2019-1.uniroma2.it (smtpauth-2019-1.uniroma2.it [160.80.5.46]) by smtp-2015.uniroma2.it (8.14.4/8.14.4/Debian-8) with ESMTP id 02V1WGxM018227; Tue, 31 Mar 2020 03:32:21 +0200 Received: from [192.168.1.80] (93-36-196-249.ip61.fastwebnet.it [93.36.196.249]) by smtpauth-2019-1.uniroma2.it (Postfix) with ESMTPSA id DCCFC122910; Tue, 31 Mar 2020 03:32:11 +0200 (CEST) DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=uniroma2.it; s=ed201904; t=1585618332; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ZA+BuNkoFMZJknutDx9BJWIxQCcnJxRo/IgWfooEnog=; b=Gmmobygek/JzH4NA5PhWAxPvnT6YH1naati8gdJlEiM9zdy+rv7YVp28nAOthvhwQkeAQv 6x9zhC7058T1IyBg== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=uniroma2.it; s=rsa201904; t=1585618332; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ZA+BuNkoFMZJknutDx9BJWIxQCcnJxRo/IgWfooEnog=; b=RFNKoRW/Vx7Q6+sszu/W2zY044+ZJ29E/SSpS4ZW6BYb2bBv3hOJq20022tJiJhvjEWkJO o7x99wRN4HnwerNR3DeU0Zg0iYA4Dn4hJqA1akiDLjxLvaUB4FsNvPBkTU+kNPKdSlMIWz uaQg+PEbBaZusr/dvNu8H8wh2szIMdNyHM8prN7LuG3Xp5Z27LIDgfqWk53PfMBE+HBDGi YFwYLJpKZ+2qdf2sz6OF8drqaPYsaX5ls3sYt0teLp7ylFhP8TlGjgok03c4VuQydclIWc 31V/7JTfynGdUEvhLfEm9ppDEuyG0flQD+RN4ggKvp8LGT/vee8GNqkYPmF+3g== Subject: Re: [net-next] seg6: add support for optional attributes during behavior construction To: David Miller Cc: kuznet@ms2.inr.ac.ru, yoshfuji@linux-ipv6.org, dav.lebrun@gmail.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, leon@kernel.org, ast@kernel.org, daniel@iogearbox.net, kafai@fb.com, songliubraving@fb.com, yhs@fb.com, andriin@fb.com, bpf@vger.kernel.org, paolo.lungaroni@cnit.it, ahmed.abdelsalam@gssi.it References: <20200319183641.29608-1-andrea.mayer@uniroma2.it> <20200325.193016.1654692564933635575.davem@davemloft.net> <20200331012348.e0b2373bd4a96fecc77686b6@uniroma2.it> <20200330.174944.1829532392145435132.davem@davemloft.net> From: Stefano Salsano Message-ID: <1a9409cd-0e2b-577b-f522-4149beca9d7c@uniroma2.it> Date: Tue, 31 Mar 2020 03:32:11 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <20200330.174944.1829532392145435132.davem@davemloft.net> Content-Type: text/plain; charset=iso-8859-15; format=flowed Content-Language: it-IT Content-Transfer-Encoding: 7bit X-Virus-Scanned: clamav-milter 0.100.0 at smtp-2015 X-Virus-Status: Clean Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Il 2020-03-31 02:49, David Miller ha scritto: > From: Stefano Salsano > Date: Tue, 31 Mar 2020 01:23:48 +0200 > >> Of course a new application (e.g. iproute2, pyroute) using a new optional >> parameter will not work on older kernels, but simply because the new parameter >> is not supported. It will not work even without our proposed patch. >> >> On the other hand, we think that the solution in the patch is more backward >> compatible. Without the patch, if we define new attributes, old applications >> (e.g. iproute2 scripts) will not work on newer kernels, while with the optional >> attributes approach proposed in the patch they will work with no issues ! > > Translation: You want to add backwards compatibility problems because > otherwise you'll have to add backwards compatibility problems. no this is not the correct translation :-) we do not want to add any backward compatility problem we need to add a number of new parameters, if we keep the current approach these parameters will be mandatory and we will have backward compatibility problems: old applications will not work with new kernels if we are allowed to add optional parameters, old applications and new applications will be able to work with old kernels and new kernels in any combination > Sorry, I'm still not convinced. > > You must find another way to achieve your objective. -- ******************************************************************* Stefano Salsano Professore Associato Dipartimento Ingegneria Elettronica Universita' di Roma Tor Vergata Viale Politecnico, 1 - 00133 Roma - ITALY http://netgroup.uniroma2.it/Stefano_Salsano/ E-mail : stefano.salsano@uniroma2.it Cell. : +39 320 4307310 Office : (Tel.) +39 06 72597770 (Fax.) +39 06 72597435 *******************************************************************