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=-13.2 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL 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 C8450C63798 for ; Fri, 20 Nov 2020 03:55:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6816A22365 for ; Fri, 20 Nov 2020 03:55:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="NWRbI5bK" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726122AbgKTDz1 (ORCPT ); Thu, 19 Nov 2020 22:55:27 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47040 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725937AbgKTDz1 (ORCPT ); Thu, 19 Nov 2020 22:55:27 -0500 Received: from mail-yb1-xb44.google.com (mail-yb1-xb44.google.com [IPv6:2607:f8b0:4864:20::b44]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6A466C0613CF for ; Thu, 19 Nov 2020 19:55:25 -0800 (PST) Received: by mail-yb1-xb44.google.com with SMTP id v92so7348101ybi.4 for ; Thu, 19 Nov 2020 19:55:25 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=5FzFYaey8liBWPJFQwuMtk0+xYf//gOPidhBjOFWJJo=; b=NWRbI5bK4VwLwrauuA4RZ7iGNnK8D5r6VpE42X7O3jpgyh1h+mvGwlwlsqtp6yCjjl 9BbwV8+iFE63ZtdY1mXYIrRt1oPsaGcnyTmfpwEY60cuPU0zX+XMebcO/FnhbaY5CFpc 6B73IAayiMPunhrK1SmHbFxdOT3J3K27ECCoPvekYWdX2sO7tfteMs1bQ4jE4OhcULYb SmUdU0SmluaF3jukJDHEol+UxQO66ltzh5r2/j9VMph9aWaZC2wdB409wK02cqQphp+c /BVBpoizicMdsriygGNFgBeZyS9SzxQ0jNH4MmWa49xeRUH0cr08saddeD7d00mVzdS1 5Rbw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=5FzFYaey8liBWPJFQwuMtk0+xYf//gOPidhBjOFWJJo=; b=A3riBEYsD7l3NDoAatAPFbUpls/dUUjuvfShRK7wEWpwekGuYjv4H6Wkez1EHdpCh/ QDAZl9rEbFqb27HJufA4tERqKFDkvHZInJW3Snt80jfHMx5YP6nNFPk8UwM5YZDz2R9U ZYYctPW4Y1OG2rmDizVVKCdxgd2ktw0oQgeHQHHjf6ZMWqnXt6wI5td/eFW9rGjSVO6M V7RX7leitwHBZWlZfWhtUfDVlKT2Mv+63UwwhJmg/s1Lnzpv5bkFH/jGx4wdMTKlFCkr FzeTskzEX82mbbIcOCkIpvMlGhbiC7+Kb9q4fYCqA0isduvgXmnZ4F2hilkyfNPxb4Y0 t+Hg== X-Gm-Message-State: AOAM532W4LAaMywMUQsFdOwkNcboI3h8hHNAph25ZiK2CAkbissj6c8S cXxFW5jr4VHjtf3Lf83E9b5ecwY3s8xQ5Z2/S8L+9Q== X-Google-Smtp-Source: ABdhPJxL9gRQiWuSir7oJokARLblIw7pfGlutKoNggm+9lZQXmMb6ZjasAEB3nZU2Er8gR5xjTv57P7WoCdTMBe7vY4= X-Received: by 2002:a25:848e:: with SMTP id v14mr17604149ybk.153.1605844524054; Thu, 19 Nov 2020 19:55:24 -0800 (PST) MIME-Version: 1.0 References: <20201111204308.3352959-1-jianyang.kernel@gmail.com> <20201114101709.42ee19e0@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> <20201116123447.2be5a827@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> <20201117171830.GA286718@shredder.lan> <7e16f1f3-2551-dff5-8039-bcede955bbfc@6wind.com> In-Reply-To: From: =?UTF-8?B?TWFoZXNoIEJhbmRld2FyICjgpK7gpLngpYfgpLYg4KSs4KSC4KSh4KWH4KS14KS+4KSwKQ==?= Date: Thu, 19 Nov 2020 19:55:08 -0800 Message-ID: Subject: Re: [PATCH net-next] net-loopback: allow lo dev initial state to be controlled To: nicolas.dichtel@6wind.com Cc: David Ahern , Ido Schimmel , Jakub Kicinski , Jian Yang , David Miller , linux-netdev , Jian Yang , Eric Dumazet Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, Nov 19, 2020 at 12:03 AM Nicolas Dichtel wrote: > > Le 18/11/2020 =C3=A0 18:39, Mahesh Bandewar (=E0=A4=AE=E0=A4=B9=E0=A5=87= =E0=A4=B6 =E0=A4=AC=E0=A4=82=E0=A4=A1=E0=A5=87=E0=A4=B5=E0=A4=BE=E0=A4=B0) = a =C3=A9crit : > > On Wed, Nov 18, 2020 at 8:58 AM Nicolas Dichtel > > wrote: > >> > >> Le 18/11/2020 =C3=A0 02:12, David Ahern a =C3=A9crit : > >> [snip] > >>> If there is no harm in just creating lo in the up state, why not just= do > >>> it vs relying on a sysctl? It only affects 'local' networking so no r= eal > >>> impact to containers that do not do networking (ie., packets can't > >>> escape). Linux has a lot of sysctl options; is this one really needed= ? > >>> > > I started with that approach but then I was informed about these > > containers that disable networking all together including loopback. > > Also bringing up by default would break backward compatibility hence > > resorted to sysctl. > >> +1 > >> > >> And thus, it will benefit to everybody. > > > > Well, it benefits everyone who uses networking (most of us) inside > Sure. > > > netns but would create problems for workloads that create netns to > > disable networking. One can always disable it after creating the netns > > but that would mean change in the workflow and it could be viewed as > > regression. > The networking is very limited with only a loopback. Do you have some rea= l use > case in mind? My use cases all use networking but I think principally we cannot break backward compatibility, right? Jakub, WDYT?