Re: Network Programming - Penultimate Segment Popping

Fernando Gont <fernando@gont.com.ar> Thu, 05 December 2019 20:51 UTC

Return-Path: <fernando@gont.com.ar>
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 3886A120137; Thu, 5 Dec 2019 12:51:31 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.9
X-Spam-Level:
X-Spam-Status: No, score=-1.9 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001] autolearn=ham autolearn_force=no
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 8AxGYOoXxTGk; Thu, 5 Dec 2019 12:51:29 -0800 (PST)
Received: from fgont.go6lab.si (fgont.go6lab.si [91.239.96.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id DB9661200EF; Thu, 5 Dec 2019 12:51:28 -0800 (PST)
Received: from [192.168.4.77] (unknown [190.179.35.56]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by fgont.go6lab.si (Postfix) with ESMTPSA id 680F48666C; Thu, 5 Dec 2019 21:51:25 +0100 (CET)
Subject: Re: Network Programming - Penultimate Segment Popping
To: "Darren Dukes (ddukes)" <ddukes@cisco.com>, Ron Bonica <rbonica=40juniper.net@dmarc.ietf.org>
Cc: SPRING WG <spring@ietf.org>, 6man <6man@ietf.org>
References: <BN7PR05MB56998A05469327E759B5B671AE5D0@BN7PR05MB5699.namprd05.prod.outlook.com> <3AD3BD11-8C34-41FE-B88F-49A9F2561D78@cisco.com>
From: Fernando Gont <fernando@gont.com.ar>
Autocrypt: addr=fernando@gont.com.ar; prefer-encrypt=mutual; keydata= mQINBE5so2gBEACzBQBLUy8nzgAzSZn6ViXT6TmZBFNYNqTpPRvTVtUqF6+tkI+IEd9N2E8p pXUXCd0W4dkxz6o7pagnK63m4QSueggvp881RVVHOF8oTSHOdnGxLfLeLNJFKE1FOutU3vod GK/wG/Fwzkv9MebdXpMlLV8nnJuAt66XGl/lU1JrNfrKO4SoYQi4TsB/waUQcygh7OR/PEO0 EttiU8kZUbZNv58WH+PAj/rdZCrgUSiGXiWUQQKShqKnJxLuAcTcg5YRwL8se/V6ciW0QR9i /sr52gSmLLbW5N3hAoO+nv1V/9SjJAUvzXu43k8sua/XlCXkqU7uLj41CRR72JeUZ4DQsYfP LfNPC98ZGTVxbWbFtLXxpzzDDT8i3uo7w1LJ2Ij/d5ezcARqw01HGljWWxnidUrjbTpxkJ9X EllcsH94mer728j/HKzC9OcTuz6WUBP3Crgl6Q47gY5ZIiF0lsmd9/wxbaq5NiJ+lGuBRZrD v0dQx9KmyI0/pH2AF8cW897/6ypvcyD/1/11CJcN+uAGIrklwJlVpRSbKbFtGC6In592lhu7 wnK8cgyP5cTU+vva9+g6P1wehi4bylXdlKc6mMphbtSA+T3WBNP557+mh3L62l4pGaEGidcZ DLYT2Ud18eAJmxU3HnM8P3iZZgeoK7oqgb53/eg96vkONXNIOwARAQABtCVGZXJuYW5kbyBH b250IDxmZ29udEBzaTZuZXR3b3Jrcy5jb20+iQJBBBMBAgArAhsjBQkSzAMABgsJCAcDAgYV CAIJCgsEFgIDAQIeAQIXgAUCTmylpQIZAQAKCRCuJQ1VHU50kv7wD/9fuNtTfxSLk3B3Hs3p ixTy8YXVjdkVwWlnJjFd7BOWmg7sI+LDhpjGfT6+ddOiwkumnvUZpObodj4ysH0i8c7P4C5t F9yu7WjklSlrB5Rth2CGChg5bKt541z2WHkFFxys9qBLmCSYDeKQkzLqhCjIUJizY2kOJ2GI MnSFDzJjhSFEh//oW830Y8fel1xnf/NVF+lBVtRMtMOfoWUqDjvP3sJ1G4zgkDCnF0CfncLx +hq2Mv26Uq9OTzvLH9aSQQ/f067BOkKAJKsfHdborX4E96ISTz57/4xECRSMr5dVsKVm4Y// uVIsb+L5z+a32FaiBZIAKDgnJO7Z8j6CV5e5yfuBTtX52Yi9HjYYqnYJGSDxYd6igD4bWu+7 xmJPHjkdqZgGV6dQIgiUfqkU+s5Cv350vK48CMaT/ZLo2BdsMhWsmaHmb+waePUMyq6E4E9x 9Js+EJb9ZiCfxS9exgieZQpet1L36IvhiwByvkQM009ywfa30JeMOltUtfLi5V06WQWsTzPL 5C+4cpkguSuAJVDTctjCA0moIeVDOpJ8WH9voQ4IeWapQnX35OIoj1jGJqqYdx65gc1ygbyx b8vw+pJ9E5GLse5TQnYifOWpXzX9053dtbwp/2OVhU4KLlzfCPCEsoTyfu9nIZxdI2PMwiL5 M85BfjX4NmwBLmPGoLkCDQRObKNoARAAqqXCkr250BchRDmi+05F5UQFgylUh10XTAJxBeaQ UNtdxZiZRm6jgomSrqeYtricM9t9K0qb4X2ZXmAMW8o8AYW3RrQHTjcBwMnAKzUIEXXWaLfG cid/ygmvWzIHgMDQKP+MUq1AGQrnvt/MRLvZLyczAV1RTXS58qNaxtaSpc3K/yrDozh/a4pu WcUsVvIkzyx43sqcwamDSBb6U8JFoZizuLXiARLLASgyHrrCedNIZdWSx0z0iHEpZIelA2ih AGLiSMtmtikVEyrJICgO81DkKNCbBbPg+7fi23V6M24+3syHk3IdQibTtBMxinIPyLFF0byJ aGm0fmjefhnmVJyCIl/FDkCHprVhTme57G2/WdoGnUvnT7mcwDRb8XY5nNRkOJsqqLPemKjz kx8mXdQbunXtX9bKyVgd1gIl+LLsxbdzRCch773UBVoortPdK3kMyLtZ4uMeDX3comjx+6VL bztUdJ1Zc9/njwVG8fgmQ+0Kj5+bzQfUY+MmX0HTXIx3B4R1I1a8QoOwi1N+iZNdewV5Zfq+ 29NlQLnVPjCRCKbaz9k6RJ2oIti55YUI6zSsL3lmlOXsRbXN5bRswFczkNSCJxJMlDiyAUIC WOay7ymzvgzPa+BY/mYn94vRaurDQ4/ljOfj6oqgfjts+dJev4Jj89vp8MQI3KJpZPEAEQEA AYkCJQQYAQIADwUCTmyjaAIbDAUJEswDAAAKCRCuJQ1VHU50km4xEACho45PZrUjY4Zl2opR DFNo5a6roTOPpgwO9PcBb3I5F8yX2Dnew+9OhgWXbBhAFq4DCx+9Gjs43Bn60qbZTDbLGJ/m 8N4PwEiq0e5MKceYcbetEdEUWhm5L6psU9ZZ82GR3UGxPXYe+oifEoJjOXQ39avf9S8p3yKP Diil0E79rn7LbJjMcgMLyjFg9SDoJ6pHLtniJoDhEAaSSgeV7Y745+gyMIdtQmrFHfqrFdjq D6G0HE+Z68ywc5KN67YxhvhBmSycs1ZSKAXv1zLDlXdmjHDHkU3xMcB+RkuiTba8yRFYwb/n j62CC4NhFTuIKOc4ta3dJsyXTGh/hO9UjWUnmAGfd0fnzTBZF8Qlnw/8ftx5lt4/O+eqY1EN RITScnPzXE/wMOlTtdkddQ+QN6xt6jyR2XtAIi7aAFHypIqA3lLI9hF9x+lj4UQ2yA9LqpoX 6URpPOd13JhAyDe47cwsP1u9Y+OBvQTVLSvw7Liu2b4KjqL4lx++VdBi7dXsjJ6kjIRjI6Lb WVpxe8LumMCuVDepTafBZ49gr7Fgc4F9ZSCo6ChgQNLn6WDzIkqFX+42KuHz90AHWhuW+KZR 1aJylERWeTcMCGUSBptd48KniWmD6kPKpzwoMkJtEXTuO2lVuborxzwuqOTNuYg9lWDl7zKt wPI9brGzquUHy4qRrA==
Message-ID: <adcc1d5c-854a-500a-818e-9bc6b742ff58@gont.com.ar>
Date: Thu, 05 Dec 2019 17:50:41 -0300
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.1
MIME-Version: 1.0
In-Reply-To: <3AD3BD11-8C34-41FE-B88F-49A9F2561D78@cisco.com>
Content-Type: text/plain; charset="utf-8"
Content-Language: en-US
Content-Transfer-Encoding: 8bit
Archived-At: <https://mailarchive.ietf.org/arch/msg/ipv6/hB2rF95BLd1cTuiSMYrIFUQ3rEk>
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: Thu, 05 Dec 2019 20:51:31 -0000

On 5/12/19 13:50, Darren Dukes (ddukes) wrote:
> Hello Ron, I believe this is the fifth time you have raised this comment
> in 6man and/or spring.
> The comment has been addressed in earlier iterations. 
> 
> Let me recap.
> 
> With the PSP behavior, the SRH is only removed by the node identified in
> the destination address field of the IPv6 header.

The question if simple: If SRH is removed by the very node identified by
the destination address when SL !=0, then that's a middlebox mangling
with SRH, and not allowed by RFC8200.


  
> That destination address was placed in the SRH by the SR Source node,
> fully expecting the behavior.

Yes, SRv6 folks have expected insertion, too. However, we have an
internet standard that forbids that (including removal by middleboxes),
and hence that's not allowed -- unless you get consensus to update RFC8200.

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