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
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
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
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
Hutton, et al. Expires February 19, 2015 [Page 1]
Internet-Draft Tunnel-Protocol August 2014
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.
Hutton, et al. Expires February 19, 2015 [Page 2]
Internet-Draft Tunnel-Protocol August 2014
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
Hutton, et al. Expires February 19, 2015 [Page 3]
Internet-Draft Tunnel-Protocol August 2014
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
Hutton, et al. Expires February 19, 2015 [Page 4]
Internet-Draft Tunnel-Protocol August 2014
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
Hutton, et al. Expires February 19, 2015 [Page 5]