Re: [DNSOP] [Ext] I-D Action: draft-ietf-dnsop-svcb-https-05.txt

Ben Schwartz <bemasc@google.com> Tue, 11 May 2021 23:51 UTC

Return-Path: <bemasc@google.com>
X-Original-To: dnsop@ietfa.amsl.com
Delivered-To: dnsop@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 78BBB3A2B4A for <dnsop@ietfa.amsl.com>; Tue, 11 May 2021 16:51:23 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -17.6
X-Spam-Level:
X-Spam-Status: No, score=-17.6 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIMWL_WL_MED=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, ENV_AND_HDR_SPF_MATCH=-0.5, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, USER_IN_DEF_DKIM_WL=-7.5, USER_IN_DEF_SPF_WL=-7.5] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=google.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 0DNYftDR5z_s for <dnsop@ietfa.amsl.com>; Tue, 11 May 2021 16:51:22 -0700 (PDT)
Received: from mail-wm1-x332.google.com (mail-wm1-x332.google.com [IPv6:2a00:1450:4864:20::332]) (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 CE57B3A2B44 for <dnsop@ietf.org>; Tue, 11 May 2021 16:51:21 -0700 (PDT)
Received: by mail-wm1-x332.google.com with SMTP id u133so571729wmg.1 for <dnsop@ietf.org>; Tue, 11 May 2021 16:51:21 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=LQ+tOgoa2h4eoqFsBw+j+kqJy4YZ8Zbxyp7vlLdeCKg=; b=lrT3dncrfiUOctYxRx0821mXWVAiiAargxBzGgayTAuyWLBDgM7ppZzvTc6mTPwgqz l/vHIfO6ZWniYbwQ7EBBOZPOs2raEpQ5TBD+tQjuwnkwBAKagVszpJWv5a7+bLJrZb8K PNrXEmp98NOeA5IxieR/ZX341f3uR3i8LMDtfVPmJtVRVqDE+yD8PjaSavDkJbQ6f2ni TiYwLagSFrny//Nf8Kq+hjFxtupvR15/Pjg4PBw3NB94lyk+tKLdiycwK+7HZPlvLLQV cd5SahEG4YgbsGuIR7ixd0U3K8BQ/NUaXQgClH+WVjpwLY4BEvoeVQiofh3pxd/SXpnD 1AyQ==
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=LQ+tOgoa2h4eoqFsBw+j+kqJy4YZ8Zbxyp7vlLdeCKg=; b=pHA0zjLQJoJYXLJs5BvIUfcmTfx5XBArWExEr1gMprmcDChn+M58N3Evx9BSOf9D6s VXVVy6k7EXodfOH1QZUWDzAjLk4bta3sUDEKgTuc3lMzHNF/vxOymL9vYE+Qv/61akj+ 8Z6yoxl4YOtPnE7EhsTyw3BwrEBkwnY4fED3Nx+hWh+Q8eAZZt4DSTrjaVN+XnzXacjj Jo5YqaI1LRzhZpRraffLcep8Dpg++yEhYIi1/1vdgnEv3qcbo1EHI+BFj8fjI1Lm4kD4 iwtnMBza45+lpnJUIPUBc363aJC77IPhxsOxbQm1ny02uhNRMleplo+hBaUmL4jWUmBb Z51w==
X-Gm-Message-State: AOAM533iFfOzyVp9+Is2umOiVRdcdlbpaplET6zwDGiDl+UvgSY5cbg6 Vqf4RKxieyaQtxfu+7PTaGppT5aDpu2hJDqydBduyg==
X-Google-Smtp-Source: ABdhPJzoleYiaZxI23kow90bOl28o12V72CUB7aIrDNZgTUFO6taxz4r+E35T7EN/6/5r8WcTKqbqJm8LACvJY4w4Xc=
X-Received: by 2002:a1c:4482:: with SMTP id r124mr8326124wma.42.1620777079702; Tue, 11 May 2021 16:51:19 -0700 (PDT)
MIME-Version: 1.0
References: <F4CE48A1-7AB0-45D0-97FF-158CE3A04EE1@icann.org> <3EE971EE-0777-44D6-9CD2-771B92FFE938@hopcount.ca> <1d822219-8ab9-2cb7-d0a4-9b8afc39058d@powerdns.com> <2952D408-117B-40D0-B859-7A8E4111629E@hopcount.ca> <CAHbrMsD+uiaYQ8i58VRjF=3AtW9uAoAtgbKzNzrPZC3QCmD2pQ@mail.gmail.com> <CAH1iCirykCpqkQEizYUBYMJEXMYRGkWvnzyo-jP=XOT-4fP-EA@mail.gmail.com> <123fd984-a3e1-0d09-b745-9a7ed6260759@nic.cz> <CAHbrMsCrf8GS3N=HF53X-M0oq09yw_vKGFLU_qA6wt94-+vNXg@mail.gmail.com> <07FE2C2B-10C4-47B0-BFF7-AD8E980A2E26@hopcount.ca> <CAHbrMsB6qGs2QsvYMC9j2ahWAR80gdcsDbgihQiXYXG03OY9qQ@mail.gmail.com> <D72B8D52-50F8-457F-B123-D303F4865557@hopcount.ca> <CAHbrMsDzWjib5zfRpr3hJk4bjXjGAq9Z2pymPoLac9rJZPbWAQ@mail.gmail.com> <CAH1iCipSweK0nv06kLH0EJJD8Khn9kZTqjYLzSzN86mjr0ZQdA@mail.gmail.com> <CAHbrMsC_bjKXXWNdsDDS4jADBG0GNMMgTZCpo3JryLdwQGfbXw@mail.gmail.com> <CAH1iCipTh2iQZ8V=rnfJpomDrMGaMmHMxVs7=YEUYb6CFOAtTg@mail.gmail.com> <CAHbrMsCgG2joydsZ80DLNYP_qNOVKSqWUd_AR7Kop7w_sYBqLA@mail.gmail.com> <CAH1iCipqocx=S_DU4pDKAEfxeBi7in09bR0YZ6FPxAGniWcwaw@mail.gmail.com> <CAHbrMsBXOwLKNRpsgyFgXTeECFL=7e4s6dSjHig2tXUuWfczWQ@mail.gmail.com> <CAH1iCiozNk-hqVBiPjqXk4sZxotkZBmfK6tQLvoBuy6uHwFjaQ@mail.gmail.com>
In-Reply-To: <CAH1iCiozNk-hqVBiPjqXk4sZxotkZBmfK6tQLvoBuy6uHwFjaQ@mail.gmail.com>
From: Ben Schwartz <bemasc@google.com>
Date: Tue, 11 May 2021 16:51:08 -0700
Message-ID: <CAHbrMsBN4bYw9FGnPQVBDvpbp73H=85y908u_voPgXf03g6HmQ@mail.gmail.com>
To: Brian Dickson <brian.peter.dickson@gmail.com>
Cc: dnsop <dnsop@ietf.org>
Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg=sha-256; boundary="0000000000001ee2f005c21692de"
Archived-At: <https://mailarchive.ietf.org/arch/msg/dnsop/owUnbvxlhTXuJnQtffza-UOh9FQ>
Subject: Re: [DNSOP] [Ext] I-D Action: draft-ietf-dnsop-svcb-https-05.txt
X-BeenThere: dnsop@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: IETF DNSOP WG mailing list <dnsop.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/dnsop>, <mailto:dnsop-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/dnsop/>
List-Post: <mailto:dnsop@ietf.org>
List-Help: <mailto:dnsop-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/dnsop>, <mailto:dnsop-request@ietf.org?subject=subscribe>
X-List-Received-Date: Tue, 11 May 2021 23:51:24 -0000

On Tue, May 11, 2021 at 4:28 PM Brian Dickson <brian.peter.dickson@gmail.com>
wrote:
...

> What if, instead of overloading the Priority 0 to also mean AliasMode, you
> had AliasMode be an SvcParams entry (which, if present, would be the only
> param allowed)?
>

There are of course many possible ways to encode this kind of flag.  I
think using SvcPriority is significantly better than using a SvcParam:
- It allows recursive resolvers to implement full SVCB support without ever
parsing the SvcParams, greatly simplifying implementation.
- It's more compact.
- It allows recipients to sort the RRSet by SvcPriority, then inspect the
top-sorted entry to decide how to proceed.

Assuming that if any RRs have AliasMode, they all must, but also allowing
> multiple aliases with different priorities...
>

Multiple alias records within an RRSet are deliberately disallowed.
Supporting them would substantially complicate client behavior (which would
acquire multiple layers of retry/fallback) and additional section
processing (which could become very slow and intensive for recursive
resolvers), for no clear gain.