Internet Engineering Task Force                                A. Hutton
Internet-Draft                                                     Unify
Intended status: Standards Track                               J. Uberti
Expires: February 19, 2015                                        Google
                                                              M. Thomson
                                                                 Mozilla
                                                         August 18, 2014


             The Tunnel-Protocol HTTP Request Header Field
                 draft-ietf-httpbis-tunnel-protocol-00

Abstract

   This specification allows HTTP CONNECT requests to indicate what
   protocol will be used within the tunnel once established, using the
   Tunnel-Protocol request header field.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on February 19, 2015.

Copyright Notice

   Copyright (c) 2014 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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   publication of this document.  Please review these documents
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   include Simplified BSD License text as described in Section 4.e of




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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   2
   2.  The Tunnel-Protocol HTTP Request Header Field . . . . . . . .   2
     2.1.  Header Field Values . . . . . . . . . . . . . . . . . . .   3
     2.2.  Syntax  . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   3
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   3
   5.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     5.1.  Normative References  . . . . . . . . . . . . . . . . . .   4
     5.2.  Informative References  . . . . . . . . . . . . . . . . .   4
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   4

1.  Introduction

   The HTTP CONNECT method (Section 4.3.6 of [RFC7231]) requests that
   the recipient establish a tunnel to the identified origin server and
   thereafter forward packets, in both directions, until the tunnel is
   closed.  Such tunnels are commonly used to create end-to-end virtual
   connections, through one or more proxies, which may then be secured
   using TLS (Transport Layer Security, [RFC5246]).

   The HTTP Tunnel-Protocol header field identifies the protocol that
   will be spoken within the tunnel, using the application layer next
   protocol identifier [RFC7301] specified for TLS [RFC5246]".

   When CONNECT is used to establish a TLS tunnel, the Tunnel-Protocol
   header field may be used to carry the same next protocol label as was
   carried within the TLS handshake.  However, the HTTP-Protocol is an
   indication rather a negotiation since HTTP proxies do not implement
   the tunneled protocol.

1.1.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

2.  The Tunnel-Protocol HTTP Request Header Field

   Clients include the Tunnel-Protocol Request Header field in a HTTP
   Connect request to indicate the application layer protocol used
   within the tunnel.




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2.1.  Header Field Values

   Valid values for the protocol field are taken from the registry
   established in [RFC7301].

2.2.  Syntax

   The ABNF (Augmented Backus-Naur Form) syntax for the Tunnel-Protocol
   header field is given below.  It is based on the Generic Grammar
   defined in Section 2 of [RFC7230].

   Tunnel-Protocol = "Tunnel-Protocol":" protocol-id

   protocol-id = token ; percent-encoded ALPN protocol identifier

   ALPN protocol names are octet sequences with no additional
   constraints on format.  Octets not allowed in tokens ([RFC7230],
   Section 3.2.6) must be percent-encoded as per Section 2.1 of
   [RFC3986].  Consequently, the octet representing the percent
   character "%" (hex 25) must be percent-encoded as well.

   In order to have precisely one way to represent any ALPN protocol
   name, the following additional constraints apply:

   o  Octets in the ALPN protocol must not be percent-encoded if they
      are valid token characters except "%", and

   o  When using percent-encoding, uppercase hex digits must be used.

   With these constraints, recipients can apply simple string comparison
   to match protocol identifiers.

   For example:

            CONNECT turn_server.example.com:5349 HTTP/1.1
            Host: turn_server.example.com:5349
            Tunnel-Protocol: turn

3.  IANA Considerations

   To Be Added

4.  Security Considerations

   In case of using HTTP CONNECT to a TURN server the security
   consideration of [RFC7231], Section-4.3.6] apply.  It states that
   there "are significant risks in establishing a tunnel to arbitrary
   servers, particularly when the destination is a well-known or



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   reserved TCP port that is not intended for Web traffic.  Proxies that
   support CONNECT SHOULD restrict its use to a limited set of known
   ports or a configurable whitelist of safe request targets."

   The Tunnel-Protocol request header field described in this document
   is an optional header and HTTP Proxies may of course not support the
   header and therefore ignore it.  If the header is not present or
   ignored then the proxy has no explicit indication as to the purpose
   of the tunnel on which to provide consent, this is the generic case
   that exists without the Tunnel-Protocol header.

5.  References

5.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC3986]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
              Resource Identifier (URI): Generic Syntax", STD 66, RFC
              3986, January 2005.

   [RFC7230]  Fielding, R. and J. Reschke, "Hypertext Transfer Protocol
              (HTTP/1.1): Message Syntax and Routing", RFC 7230, June
              2014.

   [RFC7231]  Fielding, R. and J. Reschke, "Hypertext Transfer Protocol
              (HTTP/1.1): Semantics and Content", RFC 7231, June 2014.

   [RFC7301]  Friedl, S., Popov, A., Langley, A., and E. Stephan,
              "Transport Layer Security (TLS) Application-Layer Protocol
              Negotiation Extension", RFC 7301, July 2014.

5.2.  Informative References

   [RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security
              (TLS) Protocol Version 1.2", RFC 5246, August 2008.

Authors' Addresses

   Andrew Hutton
   Unify
   Technology Drive
   Nottingham  NG9 1LA
   UK

   Email: andrew.hutton@unify.com




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   Justin Uberti
   Google
   747 6th Ave S
   Kirkland, WA  98033
   US

   Email: justin@uberti.name


   Martin Thomson
   Mozilla
   331 E Evelyn Street
   Mountain View, CA  94041
   US

   Email: martin.thomson@gmail.com



































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