IETF Logo Mail Archive

Re: Death by extension header (was:RE: New Version Notification for draft-li-6man-hbh-fwd-hdr-00.txt)

Tom Herbert <tom@herbertland.com> Mon, 13 July 2020 18:12 UTC

Return-Path: <tom@herbertland.com>
X-Original-To: ipv6@ietfa.amsl.com
Delivered-To: ipv6@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 834493A1666 for <ipv6@ietfa.amsl.com>; Mon, 13 Jul 2020 11:12:28 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.897
X-Spam-Level:
X-Spam-Status: No, score=-1.897 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, SPF_HELO_NONE=0.001, SPF_NONE=0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=herbertland-com.20150623.gappssmtp.com
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id scwPuFyNkw2i for <ipv6@ietfa.amsl.com>; Mon, 13 Jul 2020 11:12:27 -0700 (PDT)
Received: from mail-ej1-x636.google.com (mail-ej1-x636.google.com [IPv6:2a00:1450:4864:20::636]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 4C3A13A1638 for <6man@ietf.org>; Mon, 13 Jul 2020 11:11:44 -0700 (PDT)
Received: by mail-ej1-x636.google.com with SMTP id n26so18383800ejx.0 for <6man@ietf.org>; Mon, 13 Jul 2020 11:11:44 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=herbertland-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=x99Sei2nG8xGx5bQbdlXtwOaHi5WANZaiBcESR8i7+U=; b=06ZvlCS+UAucmL/8GrNjT3Pt9DXHHc6xZyzbdQRzmxdMzS0/nkzbdEalfuijGWNqqn 1Cch25bAMW5MGxBcpdYFhGuCE2p/Lb5XOpsuB/dW/RxxKI1KOFfDNPdf6W/u8oGAp9aP iyj8APLoD1cO2wkWNgYl2epAZUCEiujhMQDJzu7Q3lnJrORV3/kyEhoDabInthXHfkhA CFsxJtZSeZJoxr4HGv1VFJc2R0kShAi8miOnU7s/gXX07QBCQNs1ZuukUGbt/Yo6TIg2 dXGumJfxiKGJykPzbGa2ZoZyhKVUiYaACwByH9wUr33sxrxvRlMb8rcUgqqu6GDoWNvc 3dxA==
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=x99Sei2nG8xGx5bQbdlXtwOaHi5WANZaiBcESR8i7+U=; b=YCA4x/oWRomsnzP8jSq/Eb5JHi6sV8gFjBcInNllXwBtIKj2Xp1b6EBxdYhaL+vJVQ tz2Vs5dyaHONsaujUNlDRhS69oaB9j+TYjtbPR0NY9yoVsysqzdilvJn8FJwM2PhQa0r CSEygauaXrBCYJtgX63KOGF8zITKXAcfibHe6GM0mYqU/QDL0+V0EH1+ivLYaAhKHzGU 7ymBdLdUk1/SVBtb5Hdtf/3SOaNBfXWxYWxhXw8jvqK8FG0MxoSWlWtK/IdofmBn0CWN AFIGFHh0QBW+5b+jqgPj+6KN9MOvtM5D27Q4VmKcXBNPW6TMuA1hloDjpmVlToxHnI4y dKkQ==
X-Gm-Message-State: AOAM532PTcIrIHHeAfalCl4bH/WTJY4DZZW0e9G00a3lPy/xuZY9slHS 7NX2HyukedUSGjA4wfdRpZwmE0xlzJbPigdgz4UYGF/b36Q=
X-Google-Smtp-Source: ABdhPJy7B6+lNEIqvf2RfqgIWbn26RkTECfqP9oxB0RKKaM0szV8p6GQH8Nx88etTlUh+Tt7Fw4ZGNAH441c1xT8BZE=
X-Received: by 2002:a17:906:6b0c:: with SMTP id q12mr918197ejr.525.1594663902720; Mon, 13 Jul 2020 11:11:42 -0700 (PDT)
MIME-Version: 1.0
References: <DM6PR05MB6348708352E1EE4421A61D63AE650@DM6PR05MB6348.namprd05.prod.outlook.com> <CALx6S34e21BLHRfx+p7agrzzDsx-M-XxB6cZQnWc-d0wqSesRQ@mail.gmail.com> <20200710183228.GV42197@faui48f.informatik.uni-erlangen.de> <6fc66168-f04c-c23e-856c-5a61e1a28f5f@gont.com.ar>
In-Reply-To: <6fc66168-f04c-c23e-856c-5a61e1a28f5f@gont.com.ar>
From: Tom Herbert <tom@herbertland.com>
Date: Mon, 13 Jul 2020 11:11:31 -0700
Message-ID: <CALx6S37T_7JYW=93iOhaHaq_Kw1CsaFc37sjT3Bo4Sx_wtbfqQ@mail.gmail.com>
Subject: Re: Death by extension header (was:RE: New Version Notification for draft-li-6man-hbh-fwd-hdr-00.txt)
To: Fernando Gont <fernando@gont.com.ar>
Cc: Toerless Eckert <tte@cs.fau.de>, "6man@ietf.org" <6man@ietf.org>
Content-Type: text/plain; charset="UTF-8"
Archived-At: <https://mailarchive.ietf.org/arch/msg/ipv6/BwjFdQpHyAVGQcwr0iAlrrLjXxY>
X-BeenThere: ipv6@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: "IPv6 Maintenance Working Group \(6man\)" <ipv6.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/ipv6>, <mailto:ipv6-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/ipv6/>
List-Post: <mailto:ipv6@ietf.org>
List-Help: <mailto:ipv6-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/ipv6>, <mailto:ipv6-request@ietf.org?subject=subscribe>
X-List-Received-Date: Mon, 13 Jul 2020 18:12:28 -0000

On Mon, Jul 13, 2020 at 11:01 AM Fernando Gont <fernando@gont.com.ar> wrote:
>
> On 10/7/20 15:32, Toerless Eckert wrote:
> > IMHO: See my email earlier in the thread about punting stuff to slow-path, especially when/before
> > you figure out that you should have just ignored something at linerarte.
> >
> > Aka: not sufficiently prescriptive RFCs + bad implementations == extension header based features killed in deployments.
>
> Indeed. And add to that that the EH structure itself seems to be rather
> unfriendly with some popular hardware architectures. (unless with "not
> sufficiently prescriptive RFCs" you are meaning to set the maximum
> EH-header chain length to some sane value that folks might agree to
> comply with).
>

RFC8504 implicitly does that for number of Hop-by-Hop or Destination
options in a packet:

"A host MAY impose a limit on the maximum number of non-padding
options allowed in the destination options and hop-by-hop extension
headers.  If this feature is supported, the maximum number SHOULD be
configurable, and the default value SHOULD be set to 8."

The default value of eight was derived from the number of already
defined options, extrapolation of new options that might be defined
and deployed, and discussions with some HW vendors that they can
efficiently process a small number of TLVs (as opposed to hundreds in
a packet that are possible without a limit).

Tom


> Thanks,
> --
> Fernando Gont
> e-mail: fernando@gont.com.ar || fgont@si6networks.com
> PGP Fingerprint: 7809 84F5 322E 45C7 F1C9 3945 96EE A9EF D076 FFF1
>
>
>

v2.23.0 | Report a Bug | By Email