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=-11.4 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,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 D959AC41604 for ; Wed, 7 Oct 2020 17:44:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6B95921707 for ; Wed, 7 Oct 2020 17:44:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="vMFVbnks" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728239AbgJGRop (ORCPT ); Wed, 7 Oct 2020 13:44:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33982 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727253AbgJGRoo (ORCPT ); Wed, 7 Oct 2020 13:44:44 -0400 Received: from mail-io1-xd41.google.com (mail-io1-xd41.google.com [IPv6:2607:f8b0:4864:20::d41]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8280FC061755 for ; Wed, 7 Oct 2020 10:44:44 -0700 (PDT) Received: by mail-io1-xd41.google.com with SMTP id k6so3287357ior.2 for ; Wed, 07 Oct 2020 10:44:44 -0700 (PDT) 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; bh=pfDC6ggIxducMqfO00QLvs/+qts4BSr0MlBGQbUF5sI=; b=vMFVbnksLSPZMnYebhjUT4pIxkgnHQScv8TXqKYiHD7Tey0mttN6Jm7YgvKE112q6c V7Q3MnJr+DMM2vKK/VWBDd8U5bl2THi+iIx+Lc2Ih54oUyZo2j+ToXDbehTA3UYBGU2k Y9zYLFsSc9cVNwkxQ5FXkYmtSG3AZbcEUf62DMtG/bwnvvC96Aep8hHpQbqXvWwsZUvx ZqtD+LmKNwdVyfmSqD0QR3kFigx37oPHFwg12PIRzHUg85vCCVYgH9Cr5KhNoffqMJZg +RWJo0prz/wxD9AWFoOAwaPA9QvehFDpaEgL01gmuQnQ/louWCmUMokQurAOuA6XCWU7 z6iA== 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; bh=pfDC6ggIxducMqfO00QLvs/+qts4BSr0MlBGQbUF5sI=; b=dQNccJBujzLXHggbMP/aiivUXTu8Si1j7U2DSH9wf68XI56L/HscIz4wxR2dP21ZPT vWWJzQJv3uU5A+ioD+95uXVejOMLMSa2Cpm1LYr36CavRaDbKgociOVfYwnk5wvQ0ILu SgdjjVGDBLeFhfXc+J9tzj7ch7dVXFwxJzSsAUUn8J8lCF31kjXpKlZidgQPrO1iDyjv w1zjSBAhVzUVJC6Cyp9iCf/oJPN1Y/PeYTuRU76acgBR28ygWnI/NmLHh+Nbso/XlqzO bL9UFy8d/D0KpEdkFPRo9UFUek0q/DSWy07HbgirtL1JTwq9i0w7tQAmeLog/2nDZ1oe RaLA== X-Gm-Message-State: AOAM530HXsvqvf9Av9I6TgJQ9gtv99aLlGjruNztEp/9y0JrRX6F9Yxe ryfAckN++zKlfT0tYuIJ1LviyQlDwMcE2xJ8nCiHaHJhj5E= X-Google-Smtp-Source: ABdhPJw56KeOvZD9f3lZerZIs35wHKjo02gHP4gf/z4zmdfhC7ZiyVYKxDFnV+0Cn95g24vnsirmCVTGtaprjEOvTDo= X-Received: by 2002:a02:82c8:: with SMTP id u8mr3789531jag.61.1602092683565; Wed, 07 Oct 2020 10:44:43 -0700 (PDT) MIME-Version: 1.0 References: <160200013701.719143.12665708317930272219.stgit@firesoul> <160200018165.719143.3249298786187115149.stgit@firesoul> <20201006183302.337a9502@carbon> <20201006181858.6003de94@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> In-Reply-To: From: =?UTF-8?Q?Maciej_=C5=BBenczykowski?= Date: Wed, 7 Oct 2020 10:44:30 -0700 Message-ID: Subject: Re: [PATCH bpf-next V1 3/6] bpf: add BPF-helper for reading MTU from net_device via ifindex To: David Ahern Cc: Jakub Kicinski , Jesper Dangaard Brouer , bpf , Linux NetDev , Daniel Borkmann , Alexei Starovoitov , Lorenz Bauer , Shaun Crampton , Lorenzo Bianconi , Marek Majkowski , John Fastabend Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org > > FYI: It would be nice to have a similar function to return a device's > > L2 header size (ie. 14 for ethernet) and/or hwtype. > > Why does that need to be looked up via a helper? It's a static number > for a device and can plumbed to a program in a number of ways. Fair enough.