Re: I-D Action: draft-carpenter-6man-rfc6874bis-00.txt

Brian E Carpenter <brian.e.carpenter@gmail.com> Fri, 09 July 2021 21:33 UTC

Return-Path: <brian.e.carpenter@gmail.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 2885C3A2FC3 for <ipv6@ietfa.amsl.com>; Fri, 9 Jul 2021 14:33:09 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.436
X-Spam-Level:
X-Spam-Status: No, score=-2.436 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, NICE_REPLY_A=-0.338, RCVD_IN_DNSWL_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=gmail.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 egTup0yrlynz for <ipv6@ietfa.amsl.com>; Fri, 9 Jul 2021 14:33:04 -0700 (PDT)
Received: from mail-pf1-x429.google.com (mail-pf1-x429.google.com [IPv6:2607:f8b0:4864:20::429]) (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 326513A2FC2 for <ipv6@ietf.org>; Fri, 9 Jul 2021 14:33:04 -0700 (PDT)
Received: by mail-pf1-x429.google.com with SMTP id 21so9956647pfp.3 for <ipv6@ietf.org>; Fri, 09 Jul 2021 14:33:04 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-language:content-transfer-encoding; bh=rfl7ODD6fiGDR4HKskfsuA8rLxp+Vs821hhMM6KItjM=; b=hAlh+luvn3dFEsVdCobRr3vzGteugGmWflGQtEGBOaeQYipsl3HN5uEl5nQ59oB8hV 61J5Jpyll5K0VJrTnFab7N3QCXDmHKyC/o5Ev5T0YjKEhkm1LiLb9Vxq+s98SDbuAuOe F5YnLMy0MjT5pBC4nsQtDlTty4odyY1Fi3RPLDVM4yi+4i1Pa1n8QQDwaJGWDXNU10Kn ppJeGR7LvsHIXGp/ilcWP2ICP96M1Sh3xJnoehbH1+1ERqTY2H+wJjJT0KxrIaqi5v94 BekZcbcOTeXTUMuhJejNMMRUmgTYPiLCFgGQ73lhhflQIq68SmoxkC28E8MMmk18sWrm kHxQ==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=rfl7ODD6fiGDR4HKskfsuA8rLxp+Vs821hhMM6KItjM=; b=mn9kOvumOeypUTAO5czjf8JI1iFAc15GYkfGCSEXkaXhSqln5zPDj2lqZUN4ILIIZb y4WRXABldZRfVcQHTETZ4oz9pTdJ65KXN7Fv3jXzEtVENEXinNqh+o6OyMvGjjERdQpZ 7x9rTo/+3dmRfQ1BuLtbMcKScwFtxqplZuPTYl0Gi58O/iR5Kr2tt6M+jlztjSB2hYJ1 P1WUyauPK2+gvXtFhOXSM2RTgY977EEvskukMDHD1KAtY20qe+Vj8iJ7qIpQOBj1f7qc F9rgivAvbtMXqEKZaas7TM6vLlM1D/wbwqb0QmQN3u7Gu9C6Ypf3LA8rI/0BBlf2Xi/m uSrQ==
X-Gm-Message-State: AOAM531gg897LLRlNqBJFFp7F8ehV67uyRcfoEZsy37dMQbKZSfhMPP5 0+wBXJbgIyMxTUNNMgr4oG0p5LuJEMhP/Q==
X-Google-Smtp-Source: ABdhPJzK54XCIv6WeHnXVhTPIp4dUxbuTdpfmjCh40W5I0MHsOzM3fcjKm9JeHZDwY8I20yWByIt/g==
X-Received: by 2002:a63:3d04:: with SMTP id k4mr6195037pga.99.1625866382885; Fri, 09 Jul 2021 14:33:02 -0700 (PDT)
Received: from ?IPv6:2406:e003:1188:5b01:80b2:5c79:2266:e431? ([2406:e003:1188:5b01:80b2:5c79:2266:e431]) by smtp.gmail.com with ESMTPSA id m18sm7707187pff.88.2021.07.09.14.33.00 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 09 Jul 2021 14:33:02 -0700 (PDT)
Subject: Re: I-D Action: draft-carpenter-6man-rfc6874bis-00.txt
To: Andrew Cady <andy@cryptonomic.net>, 6MAN WG <ipv6@ietf.org>
References: <20210706152527.j47rcxas5nwz5d63@zukertort.childrenofmay.org> <CA+9kkMDGQxFD6v=NJaDXRdRJ3jaRriTnhnyKeK3cG=jaosQhBQ@mail.gmail.com> <20210706161859.2wdw7mkeg4b7nd66@zukertort.childrenofmay.org> <28125.1625590441@localhost> <20210706170435.2dfvdx2aynpqxwl6@zukertort.childrenofmay.org> <24972.1625597141@localhost> <20210706200508.tc6tl4s7cqe4k3ga@zukertort.childrenofmay.org> <54007d49-0bb7-d97e-a7cc-6d6d982c0493@gmail.com> <CA+9kkMCOWVtjrZwrSp-qO9r4oOCSwm90sJ9NVb8uXDB3xraQWA@mail.gmail.com> <9cdae794-0f9d-1b40-9aac-7c09e604324a@gmail.com> <20210709051943.7p2jx6pfivujbrqp@zukertort.childrenofmay.org>
From: Brian E Carpenter <brian.e.carpenter@gmail.com>
Message-ID: <1532a3d8-2238-6d88-554a-b6c6f1becd07@gmail.com>
Date: Sat, 10 Jul 2021 09:32:57 +1200
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.10.0
MIME-Version: 1.0
In-Reply-To: <20210709051943.7p2jx6pfivujbrqp@zukertort.childrenofmay.org>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: quoted-printable
Archived-At: <https://mailarchive.ietf.org/arch/msg/ipv6/xtug-Yqzkd9SmSoujZK4Llmnssg>
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: Fri, 09 Jul 2021 21:33:09 -0000

Andrew,

On 09-Jul-21 17:19, Andrew Cady wrote:
> On Thu, Jul 08, 2021 at 09:56:43AM +1200, Brian E Carpenter wrote:
>> On 07-Jul-21 19:39, Ted Hardie wrote:
>>>
>>> The difficulty with this approach is that it requires you to treat
>>> the % with different semantics depending on where it occurs in the
>>> URI. 
>>>
>>> From a specification perspective, that's a major change from the
>>> philosophy in the development of URIs which were attempting to be,
>>> well, uniform.  From a practical perspective, it may look easy when
>>> you use a parser with a specific order of operations, but it ends up
>>> ossifying that order into the base spec.  That may not be a great
>>> thing (or possibly, given the breadth of schemes which might use
>>> this production).
>>
>> Exactly my point, Ted, but Andrew disputes it.
> 
> I acknowledge that you can't pct-decode unreserved characters on a
> first pass before parsing out the IPv6 literal field and still use the
> unencoded % as syntax within that field.
> 
> Yet even a parser that _does_ decode unreserved before parsing still
> won't ever mix up the _boundary_ of the IPv6 address based on whether %
> is within it.  So why does it matter?
> 
> Either an implementation has been updated to support the fe80 address
> syntax or not.
> 
> If not, the fact those addresses won't work doesn't matter.  It only
> matters whether a failure mode is harmful.  It looks like the failure
> mode is at worst IPv6 parse constructing an unzoned fe80 address that
> can't be connected to, and in practice probably a parse error like "URL
> using bad/illegal format or missing URL".
> 
> If the implementation has been updated, the update can simply include
> not decoding %25 within the square brackets.

We really need to hear from implementers about this. Assuming that we
have a constructive discussion during the upcoming 6MAN session,
outreach to implementers should be the next step, IMHO.

     Brian