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 9E728C6379F for ; Wed, 18 Nov 2020 17:40:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3DA8B248EA for ; Wed, 18 Nov 2020 17:40:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="eBC9l5Rt" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727880AbgKRRj7 (ORCPT ); Wed, 18 Nov 2020 12:39:59 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40336 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725943AbgKRRj7 (ORCPT ); Wed, 18 Nov 2020 12:39:59 -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 E2B5CC0613D4 for ; Wed, 18 Nov 2020 09:39:58 -0800 (PST) Received: by mail-yb1-xb44.google.com with SMTP id s8so2427843yba.13 for ; Wed, 18 Nov 2020 09:39:58 -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=8KABC7APAn8HWA8TUE8T9+tys79NOmtJFfJcRi/4C4I=; b=eBC9l5RtAldDUzm/Swnmpe8GqncqaMDFpvz2ziv0bpSiC3Fb3e7bAuLhGf88gU27Ic MTWO+KKN1t6975nkjXyDaFXvYNNy21AsmOnZsPw1QSZK/MJWJRScQa0O+Xb+ZPMu13Ne CsYhb+T67dN/V8GWLd8ZBJ2RnBre1115cEVjM2Vh+K7fMDUPrI1rKwaH3iM9HQNidTUC ly9dUrBGxzAtx6qKhFpytW5VITlBmv/AtQAVgwggZn5O2C0wSllBykp/FhDQ4Gz1ZQ48 s2xKhQJjMWfdZdUllPSv+T+SWiLKvsmQ/idhZkv5u8BT+quh4IA+TnZHzbo1goW7WGI3 q0rQ== 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=8KABC7APAn8HWA8TUE8T9+tys79NOmtJFfJcRi/4C4I=; b=XCW1F2VTi3ZdS8I02FhRJj0lGcypAnrMj9i0H25Y1YYSwNyl7lLvDV6Ak/tn86/tL/ +2L3iPk1455I4aeq7DoM7bF8T6dp/oIFM+E1D4GlU0zgX6LPi77t9g0FubshkRu2xLPl vkvO0TaWAMcoo9ln9tt6fRoBQ4UzoKQXgkiVQCym4OdhUpWvHnlHC/3f6g2f7PYAG60Y sMHW8na9M+VJIIDq7reaTXGb3FLFu0PqlE0Y+d1m3gyVVQZNjzq/rOfVjCh1EjrjDNoD qcjfXZvK6lY9znL68iQcVDXuqO8pWqck/pb7UecFWfyVbAB8dJS3wJew0HmhOYy99B68 5TEQ== X-Gm-Message-State: AOAM532BHvqkIbtHojNBcYqnfHz2ZWWXKquWTQNyhqhCnCzEdUIAegS0 s/erMoyWzt1SzL3JyAIefI2nWkw74ZwtgwxUL8krPw== X-Google-Smtp-Source: ABdhPJyIE2ulk8C+0sDc6GnwZF0VpOpamECPcMk9eLOaLKYgEDsPN+7xMnBUuD0/w/7azmUdtnrY2RK2/tFdSPTyrWQ= X-Received: by 2002:a25:6ec3:: with SMTP id j186mr7542169ybc.335.1605721197822; Wed, 18 Nov 2020 09:39:57 -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: <7e16f1f3-2551-dff5-8039-bcede955bbfc@6wind.com> From: =?UTF-8?B?TWFoZXNoIEJhbmRld2FyICjgpK7gpLngpYfgpLYg4KSs4KSC4KSh4KWH4KS14KS+4KSwKQ==?= Date: Wed, 18 Nov 2020 09:39:41 -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 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 d= o > > it vs relying on a sysctl? It only affects 'local' networking so no rea= l > > 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 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.