From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf1-x131.google.com (mail-lf1-x131.google.com [IPv6:2a00:1450:4864:20::131]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 806263B29D for ; Tue, 29 Dec 2020 15:59:27 -0500 (EST) Received: by mail-lf1-x131.google.com with SMTP id 23so33431004lfg.10 for ; Tue, 29 Dec 2020 12:59:27 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=1HqkjhYf6LSwhiYASJpuDXCChLlD9GLVjctO5xsY5Xw=; b=Qlg5pEND0DT8pE6xBhZqwU8444qmb/TRJWE08WQ/y56jdzHjwXJ4wDt4UMLgzmgbZ4 i9bpf74MJ1sejjLaGFWFXzeQ0UOf+beDeDkj2/tSsPiF/ZdxG2zjToEI36iriAqFg4bh ymMM/34XAw7nTcFZOs0rNQvGavm+bwYA/z68TQvXgB68hN+ZA3/ciq9O1wEbthnC5y4x 1YM0JFRQfq1i3AHkhsGp4CvftXMHKIMRkQ4x4K5IO4njQxnYNbY/Vjby1dAGkctfHeb+ d41frGo1MWnwY37Dnlq1wDxpZ8eDapVgLN0vn1VH7MG6eZo+sXfpiEt0HwePAUpu5rU9 aKFg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=1HqkjhYf6LSwhiYASJpuDXCChLlD9GLVjctO5xsY5Xw=; b=HN8lNgewL6QLklcNJes9jVLZAfcLEo2IQGMyxjbfbaGYsnxN3/moqHChyxO69VT3G7 x1TUoAmc1BGAcSTW5wBo+3aiksQV89Vnp6kL2TT7zbYGjDXMjzjcPrMvw1AUX2XiDdrx 6GKVmc2VRT1ytonetB5Mfuxktlb+HFVp/HTObjQ1UHXRWnsJzHkFxElMTLsU7uNQEdju wddEMTiXDZVJBoK9ZVuMlp/rHZvbiW+SyAN48Bsp8Xa446nBuDU3xxi7+WLOU6S3BGgj x00LsXAeoUxn64eJ54V6qWNRDHx/EjQ82cShT0bc3iW5z3Co8oVG16HU6WbYE0jpnH9N RH6Q== X-Gm-Message-State: AOAM530YArdfzaNjZrvqRX3saOu3dl8rlqcRkR1PCAKda0bciUufVV1v 10EFaO61jbHPuWMqsljU/uk= X-Google-Smtp-Source: ABdhPJyqMV4ynTErmArlZveoifNT/FAC9teeinWA/NO3AaJvlWEx2bhcoVkDFRGXP/Z6/ZFiWMIZ/A== X-Received: by 2002:a2e:7a12:: with SMTP id v18mr26266361ljc.72.1609275565957; Tue, 29 Dec 2020 12:59:25 -0800 (PST) Received: from jonathartonsmbp.lan (178-55-231-236.bb.dnainternet.fi. [178.55.231.236]) by smtp.gmail.com with ESMTPSA id u3sm5691096lff.259.2020.12.29.12.59.25 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Tue, 29 Dec 2020 12:59:25 -0800 (PST) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 11.5 \(3445.9.7\)) From: Jonathan Morton In-Reply-To: <202012292013.0BTKDGCk078796@gndrsh.dnsmgr.net> Date: Tue, 29 Dec 2020 22:59:23 +0200 Cc: Dave Taht , ECN-Sane Content-Transfer-Encoding: quoted-printable Message-Id: <25865485-3505-49F7-ACE4-8F13B43BC54E@gmail.com> References: <202012292013.0BTKDGCk078796@gndrsh.dnsmgr.net> To: "Rodney W. Grimes" <4bone@gndrsh.dnsmgr.net> X-Mailer: Apple Mail (2.3445.9.7) Subject: Re: [Ecn-sane] Fwd: [PATCH net] ipv4: Ignore ECN bits for fib lookups in fib_compute_spec_dst() X-BeenThere: ecn-sane@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Discussion of explicit congestion notification's impact on the Internet List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 29 Dec 2020 20:59:27 -0000 > On 29 Dec, 2020, at 10:13 pm, Rodney W. Grimes = <4bone@gndrsh.dnsmgr.net> wrote: >=20 > If these are purely kernel macros that scope of work is well = contained. Are these macro's exported from a header to userland visible = code? It appears RT_TOS is defined in a "uapi" header, that is, Userspace API. = So yes, and this also means any bugs in it have propagated into = userspace code built against it. Actually, it looks like it is not a bug in the macro itself, but in its = intended application, referring to an obsolete and very short-lived = specification. It's extracting *specifically* the widened Type of = Service bitfield, containing the non-orthogonal "flags" indicating Max = Throughput, Min Latency, Max Reliability, and Min Cost (this last being = the short-lived part of the spec, as Diffserv and ECN replaced it very = quickly). The mask specifically excludes the Precedence field and thus = the most-significant half of the Diffserv field. - Jonathan Morton=