IETF Logo Mail Archive

Re: [Tofoo] VXLAN (UDP tunnel protocols) and non-zero checksums

Joe Touch <touch@isi.edu> Thu, 01 May 2014 20:34 UTC

Return-Path: <touch@isi.edu>
X-Original-To: tofoo@ietfa.amsl.com
Delivered-To: tofoo@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 09CC71A6F62; Thu, 1 May 2014 13:34:48 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -4.851
X-Spam-Level:
X-Spam-Status: No, score=-4.851 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, RP_MATCHES_RCVD=-0.651] autolearn=ham
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 NmXy6GE9Gbzj; Thu, 1 May 2014 13:34:47 -0700 (PDT)
Received: from vapor.isi.edu (vapor.isi.edu [128.9.64.64]) by ietfa.amsl.com (Postfix) with ESMTP id 1912E1A0976; Thu, 1 May 2014 13:34:47 -0700 (PDT)
Received: from [128.9.160.166] (abc.isi.edu [128.9.160.166]) (authenticated bits=0) by vapor.isi.edu (8.13.8/8.13.8) with ESMTP id s41KY3JP013901 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NOT); Thu, 1 May 2014 13:34:03 -0700 (PDT)
Message-ID: <5362AFBB.6080008@isi.edu>
Date: Thu, 01 May 2014 13:34:03 -0700
From: Joe Touch <touch@isi.edu>
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0
MIME-Version: 1.0
To: sarikaya@ieee.org
References: <CA+mtBx8+OyN5UUsL-sS1AuPF69p6=T3kw4Mq-BogjQhEF-Cpsw@mail.gmail.com> <CAC8QAccqYygAZrX=P1S7Av4KXtU82RWANv=BAaKjYm=hDH0hAA@mail.gmail.com> <CA+mtBx9YfBtizy+a1Wi+z5isYQ7AtLm_Hevx7U66U8HS8u_6LQ@mail.gmail.com> <CAC8QAcdXLbdVw3FYcdqSg163_w76ThYXuK3M9-vvw_wx5d52_Q@mail.gmail.com> <5362ACA5.1030102@isi.edu> <CAC8QAcfi=CEc_a43R1ZgidtmdjGL2G4C_+PPj-uDCMkZ+aheuw@mail.gmail.com>
In-Reply-To: <CAC8QAcfi=CEc_a43R1ZgidtmdjGL2G4C_+PPj-uDCMkZ+aheuw@mail.gmail.com>
Content-Type: text/plain; charset="UTF-8"; format="flowed"
Content-Transfer-Encoding: 7bit
X-ISI-4-43-8-MailScanner: Found to be clean
X-MailScanner-From: touch@isi.edu
Archived-At: http://mailarchive.ietf.org/arch/msg/tofoo/spxj1Hm2bSSLBiJcpc0JTfEqUU0
Cc: "tofoo@ietf.org" <tofoo@ietf.org>, "nvo3@ietf.org" <nvo3@ietf.org>, ddutt.ietf@hobbesdutt.com, mallik_mahalingam@yahoo.com, Tom Herbert <therbert@google.com>
Subject: Re: [Tofoo] VXLAN (UDP tunnel protocols) and non-zero checksums
X-BeenThere: tofoo@ietf.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: "Discussion list for Tunneling over Foo \(with\)in IP networks \(TOFOO\)." <tofoo.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/tofoo>, <mailto:tofoo-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/tofoo/>
List-Post: <mailto:tofoo@ietf.org>
List-Help: <mailto:tofoo-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/tofoo>, <mailto:tofoo-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 01 May 2014 20:34:48 -0000

On 5/1/2014 1:30 PM, Behcet Sarikaya wrote:
>
>
>
> On Thu, May 1, 2014 at 3:20 PM, Joe Touch <touch@isi.edu
> <mailto:touch@isi.edu>> wrote:
>
>
>
>     On 4/30/2014 2:23 PM, Behcet Sarikaya wrote:
>
>         Here is what VXLAN says on tunneled traffic:
>
>         Tunneled traffic over the IP network can be secured with traditional
>              security mechanisms like IPsec that authenticate and optionally
>              encrypt VXLAN traffic. This will, of course, need to be
>         coupled with
>              an authentication infrastructure for authorized endpoints
>         to obtain
>              and distribute credentials.
>
>         Based on this, UDP checksum text seems to be consistent, no?
>
>
>     No; the UDP checksum is not for authetication. It is an error check.
>
>     The only party that can decide to make the UDP checksum optional
>     when using IPv4 is the source - by inserting zero.
>
>     It's not the receiver's choice to ignore that checksum if it's not
>     zero. That's where this doc breaks the current standards.
>
> The important point in the above text that I quoted was encryption being
> optional not about authentication.
> So checksum would be zero if the payload is encrypted and non-zero if it
> is not not and both cases are possible.

Receiver processing is simple:

	- if the checksum is zero, ignore

	- if the checksum is NOT zero, it MUST match

No other part of the packet needs to be examined. If the *sender* wants 
to have the receiver ignore the checksum, it inserts zero. If not, the 
receiver MUST process and validate it.

Joe

v2.23.0 | Report a Bug | By Email