Re: [Doh] [Ext] A question on the mix of DNS and HTTP semantics

Andrew Sullivan <ajs@anvilwalrusden.com> Mon, 19 March 2018 22:11 UTC

Return-Path: <ajs@anvilwalrusden.com>
X-Original-To: doh@ietfa.amsl.com
Delivered-To: doh@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 1283E12D94D for <doh@ietfa.amsl.com>; Mon, 19 Mar 2018 15:11:53 -0700 (PDT)
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, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (1024-bit key) header.d=yitter.info header.b=NS8Qk4a/; dkim=pass (1024-bit key) header.d=yitter.info header.b=hne30iqb
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 B2p5QyYlorYC for <doh@ietfa.amsl.com>; Mon, 19 Mar 2018 15:11:51 -0700 (PDT)
Received: from mx4.yitter.info (mx4.yitter.info [159.203.56.111]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 86F821200E5 for <doh@ietf.org>; Mon, 19 Mar 2018 15:11:51 -0700 (PDT)
Received: from localhost (localhost [127.0.0.1]) by mx4.yitter.info (Postfix) with ESMTP id A3FA3BE780 for <doh@ietf.org>; Mon, 19 Mar 2018 22:11:20 +0000 (UTC)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yitter.info; s=default; t=1521497480; bh=MXCzUAXjn4HhxgF+t0Ey4NSZIMJTBbTyKvUC6zic31w=; h=Date:From:To:Subject:References:In-Reply-To:From; b=NS8Qk4a/t4zcyapiis2bnMu39iUF8Qc9QzYOV5QC7TB4sIdWmPMsELIwGu08d6zuM 7H/HpMeJJOj4QdjBv7oEsNpVbdwWlzc7GEmHXQ+/8BtUbAabrRIF+49g92C4sBqjwJ ezs0u2rvLRdY5fiFsalW7ijHTZW8GnMa/xzJOlW8=
X-Virus-Scanned: Debian amavisd-new at crankycanuck.ca
Received: from mx4.yitter.info ([127.0.0.1]) by localhost (mx4.yitter.info [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id yZX41kDu8ud5 for <doh@ietf.org>; Mon, 19 Mar 2018 22:11:19 +0000 (UTC)
Date: Mon, 19 Mar 2018 18:11:16 -0400
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yitter.info; s=default; t=1521497479; bh=MXCzUAXjn4HhxgF+t0Ey4NSZIMJTBbTyKvUC6zic31w=; h=Date:From:To:Subject:References:In-Reply-To:From; b=hne30iqbbTpfyE2poxy8+tPYWJUngLRihbst6WnJQC5dCIlfew6ydw7kJyF/24tJs vRU7MGzqEMIvKwBQV5IeBZ6SvEBD1JTGzPURWfK5rY0q0jv6LI/+A8Pg42UEvjpZFa sXZh1xkXOmFvAMMgm3YJKDNvzoEgrZyHnVQo6vxE=
From: Andrew Sullivan <ajs@anvilwalrusden.com>
To: doh@ietf.org
Message-ID: <20180319221116.2tooil7y64lv764q@mx4.yitter.info>
References: <CA+9kkMB7awRfW9jUmY9Q-1p+w3VLtpG5DxhF3s7Q58nEMZeX3w@mail.gmail.com> <20180318164307.GB6724@laperouse.bortzmeyer.org> <CAOdDvNr1GstB+g3pYi4w0bXuQ=Nz8HqgTRfWUX9TGu9YAYiz0w@mail.gmail.com> <CA+9kkMA733q3BPRbnN++0vwKrmOOCN8SBgknYwFaeEf2cvYikw@mail.gmail.com> <88AB1743-7270-4D72-8C70-0AB6B74416BD@icann.org> <SN1PR08MB1854485BF319264F51D208C3DAD40@SN1PR08MB1854.namprd08.prod.outlook.com> <20180319150958.GA23411@laperouse.bortzmeyer.org> <20180319152126.c5ylchfawn4syfwb@mx4.yitter.info> <20180319153958.GA24327@laperouse.bortzmeyer.org>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Disposition: inline
In-Reply-To: <20180319153958.GA24327@laperouse.bortzmeyer.org>
Archived-At: <https://mailarchive.ietf.org/arch/msg/doh/Ca-VZ546iXqgzFNbLqQO6PFHiVA>
Subject: Re: [Doh] [Ext] A question on the mix of DNS and HTTP semantics
X-BeenThere: doh@ietf.org
X-Mailman-Version: 2.1.22
Precedence: list
List-Id: DNS Over HTTPS <doh.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/doh>, <mailto:doh-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/doh/>
List-Post: <mailto:doh@ietf.org>
List-Help: <mailto:doh-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/doh>, <mailto:doh-request@ietf.org?subject=subscribe>
X-List-Received-Date: Mon, 19 Mar 2018 22:11:53 -0000

On Mon, Mar 19, 2018 at 03:39:58PM +0000, Stephane Bortzmeyer wrote:
> Truncated for HTTP reasons (error 500 : the server crashed), not for
> DNS reasons.

That's what I assumed, but my point is that the rule could still be
that the client could be required to process it, because the client
would fail.  The truncated message would have a section count that was
higher than the records actually contained there (because of the
truncated message), so the client would have a partial message and
would eventually do whatever it would do in that case (in ordinary
DNS, time out).  

I think erro 500 would probably return faster, however.

> If the DNS answer is truncated for DNS reasons (EDNS buffer size too
> small), I would expect the HTTP status code to be 200.

Also ok with me.  But since it's a wire message, you still need a TC
bit set, right?  (Hard for the as-yet-unwritten cases where there are
no such header bits, though, so 200 is probably better.)

A

-- 
Andrew Sullivan
ajs@anvilwalrusden.com