Re: [v6ops] Scope of Unique Local IPv6 Unicast Addresses (Fwd: New Version Notification for draft-gont-6man-ipv6-ula-scope-00.txt)

Brian E Carpenter <brian.e.carpenter@gmail.com> Sat, 13 February 2021 21:11 UTC

Return-Path: <brian.e.carpenter@gmail.com>
X-Original-To: v6ops@ietfa.amsl.com
Delivered-To: v6ops@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 59FA23A0DFF for <v6ops@ietfa.amsl.com>; Sat, 13 Feb 2021 13:11:09 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.1
X-Spam-Level:
X-Spam-Status: No, score=-2.1 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=-0.001, 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 P0tbJcPyFNFI for <v6ops@ietfa.amsl.com>; Sat, 13 Feb 2021 13:11:07 -0800 (PST)
Received: from mail-pg1-x535.google.com (mail-pg1-x535.google.com [IPv6:2607:f8b0:4864:20::535]) (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 D87AD3A0DFC for <v6ops@ietf.org>; Sat, 13 Feb 2021 13:11:07 -0800 (PST)
Received: by mail-pg1-x535.google.com with SMTP id o21so1913074pgn.12 for <v6ops@ietf.org>; Sat, 13 Feb 2021 13:11:07 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=L/bwDFTUJ826mYk7KfA8+axMvTkTk9q1+AbDWvEm1FA=; b=vN3AZ0R1zG9/jnwTV4HV6ow2XFpPFPV4zBkLvRbmFDflFKovBD91VkpEfERqaHnKZB mYVBQUlxS2HjUZhaveupCEZ3orQ5sBLCcLpdHcp4DUPu+OMQo4AyF76RS5gGIxg32XKD 7EtoQiU9cEif73gAo6jF84Y6uNItfcKVcyiFsSWYwXbU0H7VoL0fI66j+OziDTyYEvsI YcuFELc++uqj3aOT3QzF7+g349NoOwE+DuaQEZTDDhOFm5k8T5r4CwCFJ9sEI2WhYBMr 4/W6G1ZPyF1l7MWxHOCdiN3TfTJksOiqrDI0S/DqWGvCND4ZHLmzunDySJcjEr1l76sX iZ9w==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=L/bwDFTUJ826mYk7KfA8+axMvTkTk9q1+AbDWvEm1FA=; b=frSJyDYKQI9DNIxBYnTNTGH5/CstlJcQcK3lumdoY1WsLMsoRM/FqAyLxTlGqGxNe6 L0x5iaHWLgEVmoJl5kS16OGrkyTvIuk9L5Ekbli6PSZ/LtVOh7ogQRzDRfEUwHU+Xpnx MxESHNsuvTV5qe2Wd56asApFxpx1+uwQgsHuVoB7VLwYXucnyy7A6RtpKmCXHoO9HZLT SN+JCPn9O00EhflcwmOr4idwr/USH9IKJA+qFqov3PBBGFh/X0oJOtgutg0pXmC0FtDF 9Cu0udkoniHLV3S1t1TKxnEJ/HkqhPukOSWDGdl/e+63XQg3999sZhSR2H+8/FeQIdX9 L4iw==
X-Gm-Message-State: AOAM533np5kvmjIXvmteTP1svxFN8iob+QLnXTVEZLeWZzFp0JmWBNX3 CHQG/cKW8sN6eUZZonqxRe020nGTIx2k8g==
X-Google-Smtp-Source: ABdhPJz5Sh08y6aMD0QM4nBuXlG+okBFy4VeiPydkxaGtupFYcggkpewhz6RDYD6KJN10zjA+FgC2Q==
X-Received: by 2002:a62:3181:0:b029:1df:4f2:16b3 with SMTP id x123-20020a6231810000b02901df04f216b3mr8453790pfx.24.1613250666406; Sat, 13 Feb 2021 13:11:06 -0800 (PST)
Received: from [192.168.178.20] ([151.210.131.28]) by smtp.gmail.com with ESMTPSA id n12sm12048689pff.29.2021.02.13.13.11.03 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Sat, 13 Feb 2021 13:11:05 -0800 (PST)
To: Fernando Gont <fgont@si6networks.com>, Ted Lemon <mellon@fugue.com>
Cc: v6ops@ietf.org, Fernando Gont <fernando@gont.com.ar>
References: <160989494094.6024.7402128068704112703@ietfa.amsl.com> <6fe3a45e-de65-9f88-808d-ea7e2abdcd16@si6networks.com> <F4E00812-E366-4520-AE17-7BB46E28D575@gmail.com> <b2e51a89-e8a7-9ddb-643d-63a98569b03c@si6networks.com> <CB9EA5F4-A241-46A4-A371-B2A1BFB8C72F@fugue.com> <dff93a2e-f4f8-01c9-ce88-c2dbb20a04f1@si6networks.com> <759637FF-77C7-41EA-8671-73988AD48873@fugue.com> <6ab2d348-6220-6744-9585-1f99e23a7ee0@gont.com.ar> <EFF8F0BB-D147-4D99-B17A-892825835590@fugue.com> <dd7c8d97-3f1c-e82e-4b7a-431f727adeec@si6networks.com> <B7E3D476-C4AE-425A-945E-FBCBAE1E4037@fugue.com> <9a5c8db7-3d6f-060d-33f2-1f63499a2c8e@si6networks.com> <971635b5-81c9-594a-0200-23a71d3b1f4b@gmail.com> <8ef4a730-5403-8384-e85f-bcf9e3a92ef4@si6networks.com>
From: Brian E Carpenter <brian.e.carpenter@gmail.com>
Message-ID: <2c10c9c5-d9d4-21f8-d4d7-c95e6b466b44@gmail.com>
Date: Sun, 14 Feb 2021 10:11:00 +1300
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.9.1
MIME-Version: 1.0
In-Reply-To: <8ef4a730-5403-8384-e85f-bcf9e3a92ef4@si6networks.com>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Archived-At: <https://mailarchive.ietf.org/arch/msg/v6ops/BlIjeHifixbsFofKJ_K6UW3YjHM>
Subject: Re: [v6ops] Scope of Unique Local IPv6 Unicast Addresses (Fwd: New Version Notification for draft-gont-6man-ipv6-ula-scope-00.txt)
X-BeenThere: v6ops@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: v6ops discussion list <v6ops.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/v6ops>, <mailto:v6ops-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/v6ops/>
List-Post: <mailto:v6ops@ietf.org>
List-Help: <mailto:v6ops-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/v6ops>, <mailto:v6ops-request@ietf.org?subject=subscribe>
X-List-Received-Date: Sat, 13 Feb 2021 21:11:09 -0000

On 14-Feb-21 09:33, Fernando Gont wrote:
> Hi, Brian,
> 
> On 13/2/21 17:18, Brian E Carpenter wrote:
> [....]
>>> ---- cut here ----
>>> 5.1.  Address Attributes in Programming Languages
>>>
>>>      Python's ipaddress library [Python-ipaddr] defines 'IPv6Address'
>>>      objects that have a number of attributes, including:
>>>
>>>      o  'True' if the address is allocated for private networks.
>>>
>>>      o  'True' if the address is allocated for public networks.
>>>
>>>      For ULAs, the is_private attribute is 'True', while the is_global
>>>      attribute is 'False'.  This contradicts the definition of ULAs as
>>>      having "global scope" [RFC4291] [RFC4193], but is in line with the
>>>      specification update performed by this document (see Section 6).
>>> ---- cut here ----
>>>
>>> (this one is documented in our draft, but credit goes to Brian for
>>> spotting it).
>>
>> The fact is that I spotted it due to an issue with running code.
>> Just for fun, here is the test for ULAness according to the Python
>> ipaddress module's semantics:
>>
>> def is_ula(a):
>>      """Test for ULA"""
>>      return (a.is_private and not a.is_link_local
>>               and not a.is_loopback
>>               and not a.is_unspecified)
> 
> IIRC, I don't remember seeing a "is_ula" attribute. -- will recheck.

No, there isn't. But I needed it in my code, so I wrote the function.
(It was a bit purist to write it that way rather than using the fc00::/7 mask)

   Brian

> 
> 
> 
>>> Are the is_private and is_global attributes employed by such library
>>> correct? Do they match our specs? Do they match the obvious
>>> interpretation of such attributes?  Should they be changed? Why, or why not?
>>
>> A bit off topic, but I think the .is_private attribute is a very poor
>> choice, because it might be misunderstood as implying privacy properties.
> 
> I believe the name attribute is borrowed from the IPv4 world (i.e., 
> RFC1918).
> 
> Thanks,
>