Re: [tcpm] Progressing draft-ietf-tcpm-converters

Yuchung Cheng <ycheng@google.com> Fri, 24 May 2019 15:01 UTC

Return-Path: <ycheng@google.com>
X-Original-To: tcpm@ietfa.amsl.com
Delivered-To: tcpm@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id DE9321202EC for <tcpm@ietfa.amsl.com>; Fri, 24 May 2019 08:01:35 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -7.41
X-Spam-Level:
X-Spam-Status: No, score=-7.41 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, ENV_AND_HDR_SPF_MATCH=-0.5, RCVD_IN_DNSWL_NONE=-0.0001, SPF_PASS=-0.001, T_DKIMWL_WL_MED=-0.01, URIBL_BLOCKED=0.001, URIBL_SBL=10, URIBL_SBL_A=0.1, USER_IN_DEF_DKIM_WL=-7.5, USER_IN_DEF_SPF_WL=-7.5] autolearn=no 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 Sn1t-X00Hoex for <tcpm@ietfa.amsl.com>; Fri, 24 May 2019 08:01:33 -0700 (PDT)
Received: from mail-wm1-x32d.google.com (mail-wm1-x32d.google.com [IPv6:2a00:1450:4864:20::32d]) (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 66E23120019 for <tcpm@ietf.org>; Fri, 24 May 2019 08:01:33 -0700 (PDT)
Received: by mail-wm1-x32d.google.com with SMTP id x64so9717767wmb.5 for <tcpm@ietf.org>; Fri, 24 May 2019 08:01:33 -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:content-transfer-encoding; bh=i4LtHzpVGhieVdGANC7NMRcMyb8WWtQvvU3E84PhsJk=; b=n8Prkcf4zEg9JcIW+xduqNjg59ngJ2vYUCpqu4XEzygjJzAHoDxP5AxpSQZs2Z6aXQ lHrlw36GS34AX26ag5VtGEH8bmPyXdASnLCOfO/4Sn9w265DiSxEW9bwi+SwrI4JFnNV VTRkbHBJ20LkTXLR3YHnP5ThIsK3dgnZG1YZ8/R5oF+4+O5oLZdwvTxASqtZN8K/QgOA Nhq0ZQ4dr+jBGIYPhyNol9VqvBfxLsYawU9YwyNpJb3Bj4DJM20PMPn2cVSQfKu98nqP EotkhznzbLSpxdC6MOdccjDWMCXzkm0LgA2Au43v3Dlbl3VRxfsgvJbV3mK7yKrEfuQO xhGg==
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:content-transfer-encoding; bh=i4LtHzpVGhieVdGANC7NMRcMyb8WWtQvvU3E84PhsJk=; b=b3r5VW1V2yMN0WOXWuFr8mmpevgsfBBoHK8s+zBHV5Bqw+9nb8RL6QAKOvM6WqBQWu AXXd2Gz8YQpL39cfOZz30xvYVNkC0nr2L7mbyRlqc8l0hVE5vjb9fWTod6SvAJpfwHzH k/SkjVg+3kYoFDFEwG+lK2v1jogRQVLpOHDDrPGUBezUJKdNoMgzKAC/7TQFXFmBRf5K xpDm6vpr92FCYnOKXa2DEvP7NLCfL6vU8/CbKvIkkDV7UCehmNM6y9w7zwMKTmwspYiu k6N5b/qLZUHx5Txd3z7Z2GxKnSqmy0Cl8QNYTAP4mdISu6wTbNBUgv1LujOfyl3J6GAq YAVA==
X-Gm-Message-State: APjAAAWrTuo4WrtlUS1+kogDcXvEhAqGyFD8+aoUnVmZujmFPc4grDnQ 8PFPTiiS4EPzUvkcqb1zH+yuy8NEOpXQ06kIvZ9xJoVm
X-Google-Smtp-Source: APXvYqwru+ptxw6StjccGBscirumNKWJqnDc8jDh1QIerU/emQ4FQqMYsL4chbE9SccDySSxrr3EwFCEATt355TAmZg=
X-Received: by 2002:a1c:38c5:: with SMTP id f188mr180633wma.9.1558710091205; Fri, 24 May 2019 08:01:31 -0700 (PDT)
MIME-Version: 1.0
References: <F92BF1E2-60EB-4E48-84A4-1C82589A056A@tessares.net> <CAK6E8=f-TAUWs3x4P9XHUHbvRhOqBhH9GU910Yoy5v_0vzUxAQ@mail.gmail.com> <A0496204-331F-4D8E-A1C1-83D3E1CE759B@tessares.net> <CAK6E8=e0RVzfRA0j=y8EZK0HonH6vaMBL6m-U3L+8cNO-zpqqw@mail.gmail.com> <787AE7BB302AE849A7480A190F8B93302EA8E8EF@OPEXCAUBMA2.corporate.adroot.infra.ftgroup>
In-Reply-To: <787AE7BB302AE849A7480A190F8B93302EA8E8EF@OPEXCAUBMA2.corporate.adroot.infra.ftgroup>
From: Yuchung Cheng <ycheng@google.com>
Date: Fri, 24 May 2019 08:00:53 -0700
Message-ID: <CAK6E8=cDrLB0Oop2act7jCe_CYnNd2gJZU06ZHg_zJXXh_VOXg@mail.gmail.com>
To: mohamed.boucadair@orange.com
Cc: Olivier Bonaventure <olivier.bonaventure@tessares.net>, "tcpm@ietf.org Extensions" <tcpm@ietf.org>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Archived-At: <https://mailarchive.ietf.org/arch/msg/tcpm/OY7FsRkV79X1QhoTUnmvzTnWzjQ>
Subject: Re: [tcpm] Progressing draft-ietf-tcpm-converters
X-BeenThere: tcpm@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: TCP Maintenance and Minor Extensions Working Group <tcpm.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/tcpm>, <mailto:tcpm-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/tcpm/>
List-Post: <mailto:tcpm@ietf.org>
List-Help: <mailto:tcpm-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/tcpm>, <mailto:tcpm-request@ietf.org?subject=subscribe>
X-List-Received-Date: Fri, 24 May 2019 15:01:36 -0000

On Thu, May 23, 2019 at 11:34 PM <mohamed.boucadair@orange.com>; wrote:
>
> Hi Yuchung,
>
> Please see inline.
>
> Cheers,
> Med
>
> > -----Message d'origine-----
> > De : tcpm [mailto:tcpm-bounces@ietf.org] De la part de Yuchung Cheng
> > Envoyé : jeudi 23 mai 2019 18:38
> > À : Olivier Bonaventure
> > Cc : tcpm@ietf.org Extensions
> > Objet : Re: [tcpm] Progressing draft-ietf-tcpm-converters
> >
> > On Tue, May 21, 2019 at 4:52 AM Olivier Bonaventure
> > <olivier.bonaventure@tessares.net>; wrote:
> > >
> > > Yuchung,
> > >
> > > >>
> > > >> We believe that a specialised TCP application should be allowed to
> > use its own cookie inside the payload instead of relying on the TCP header
> > to use fast open. The 0-RTT convert protocol is one example, but there
> > could be others. Looking at other application layer protocols, I noticed
> > that TLS1.3 (rfc8446) also includes a cookie which is mainly designed
> > enable servers to get a confirmation of the reachability of the client IP
> > addresses for DTLS, but the same approach could be used when TLS sends its
> > initial data in the SYN as well.
> > > >>
> > > >> Another point that should be clarified in RFC7413 are how middleboxes
> > should handle SYN packets containing a non-zero payload. According to
> > RFC793, such packets are valid TCP packets. The TFO option, defined in
> > RFC7314 is not and should not be considered as an indication that is
> > required to “authorise” the utilisation of payload inside a SYN packet.
> > During the Prague meeting, Christoph Paasch mentioned at the mike that
> > they have one application that uses data inside the SYN and their
> > measurements indicate that sending this SYN without the TFO option enables
> > it to pass through more middleboxes than when the same SYN contains the
> > TFO option.
> > > >>
> > > >> Another point is the socket API. Currently, Linux and MacOS decouple
> > the transmission of data inside the SYN from the utilisation of the TFO
> > option. This makes it possible for a client to send data inside the SYN
> > without enabling TFO. On Windows, the API seems to force the utilisation
> > of TFO when there is data in the SYN. As indicated earlier, RFC793 does
> > not mandate the presence of the TFO to place data inside the SYN.
> > > >>
> > > >> The approach we are proposing has the benefits of RFC7413 but without
> > its drawbacks. Moreover, given that RFC7413 is Experimental, we don't
> > think that there is a harm if we proceed with the approach 0-rtt convert
> > protocol while the IETF can further tweak and adjust the applicability
> > scope of RFC7413. For example, an update can be proposed to RFC7413 to
> > clarify that specialized application-level protocols could place cookie
> > information in their payload and thus not use the TFO option.
> > > > Just to confirm: you mean an API that
> > > > let application sets the TFO cookie (on either server and client)?
> > >
> > >
> > > No, we suggest to let specific applications use data in the SYN without
> > using the TFO cookie. Those applications can manage their cookie inside
> > the SYN payload if needed. Instead of having TFO cookies that are managed
> > by the TCP stack and have limited size, those specialised protocols would
> > use application-level cookies which can be longer and are managed by these
> > application protocols.
> > I see. though I suppose this requires changing RFC793 of not uploading
> > the data to application until 3WHS completes.
> >
>
> [Med] That constraint can be relaxed following a rationale similar to the one in RFC7413.
>
> Is there any particular reason why a change to RFC793 would be required here but not for RFC7413?
It's an interesting question -

RFC793 long allows data-in-SYN but requires data to be posted after
handshake. RFC7413 relaxes that but also requires a cookie.

So if we think this is an "extension" to TFO, then perhaps extends
RFC7413 not changing RFC793? personally I do think that makes sense.
IMO TFO implementation provides a generic way to do data-in-SYN.
Application can use whatever they prefer to protect or optimize
data-in-SYN. TFO cookie is just a default simple mechanism for
application who finds that acceptable.

>
> > >
> > > > otherwise obviously application can place any data in their TCP
> > payload for its
> > > > purposes.
> > >
> > > This is what we proposed in Prague, i.e. using data in the TCP SYN
> > without the TFO option.
> > >
> > >
> > > Olivier
> > > --
> > >
> > >
> > > Disclaimer: https://www.tessares.net/mail-disclaimer/
> > > <https://www.tessares.net/mail-disclaimer/>
> > >
> > >
> >
> > _______________________________________________
> > tcpm mailing list
> > tcpm@ietf.org
> > https://www.ietf.org/mailman/listinfo/tcpm