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RFC 9220 PROPOSED STANDARD HTTP · WEBSOCKET · HTTP/3

Bootstrapping WebSockets with HTTP/3

HTTP/3 rules for using Extended CONNECT to bootstrap WebSocket streams.

On rfc-editor.org ↗
PUBLISHED
June 2022
AUTHORS
R. Hamilton
STREAM
IETF
SETTING NAME
SETTINGS_ENABLE_CONNECT_PROTOCOL
SETTING VALUE
0x08
SETTING DEFAULT
0
DOI
10.17487/RFC9220

RFC text

Contents
Original text · RFC Editor View on rfc-editor.org ↗ 
Internet Engineering Task Force (IETF)                       R. Hamilton
Request for Comments: 9220                                        Google
Category: Standards Track                                      June 2022
ISSN: 2070-1721


                  Bootstrapping WebSockets with HTTP/3

Abstract

   The mechanism for running the WebSocket Protocol over a single stream
   of an HTTP/2 connection is equally applicable to HTTP/3, but the
   HTTP-version-specific details need to be specified.  This document
   describes how the mechanism is adapted for HTTP/3.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   https://www.rfc-editor.org/info/rfc9220.

Copyright Notice

   Copyright (c) 2022 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
   (https://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 Revised BSD License text as described in Section 4.e of the
   Trust Legal Provisions and are provided without warranty as described
   in the Revised BSD License.

Table of Contents

   1.  Introduction
   2.  Conventions and Definitions
   3.  WebSockets Upgrade over HTTP/3
   4.  Security Considerations
   5.  IANA Considerations
   6.  Normative References
   Acknowledgments
   Author's Address

1.  Introduction

   "Bootstrapping WebSockets with HTTP/2" [RFC8441] defines an extension
   to HTTP/2 [HTTP/2] that is also useful in HTTP/3 [HTTP/3].  This
   extension makes use of an HTTP/2 setting.  Appendix A.3 of [HTTP/3]
   gives some guidance on what changes (if any) are appropriate when
   porting settings from HTTP/2 to HTTP/3.

2.  Conventions and Definitions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

3.  WebSockets Upgrade over HTTP/3

   [RFC8441] defines a mechanism for running the WebSocket Protocol
   [RFC6455] over a single stream of an HTTP/2 connection.  It defines
   an Extended CONNECT method that specifies a new ":protocol" pseudo-
   header field and new semantics for the ":path" and ":authority"
   pseudo-header fields.  It also defines a new HTTP/2 setting sent by a
   server to allow the client to use Extended CONNECT.

   The semantics of the pseudo-header fields and setting are identical
   to those in HTTP/2 as defined in [RFC8441].  Appendix A.3 of [HTTP/3]
   requires that HTTP/3 settings be registered separately for HTTP/3.
   The SETTINGS_ENABLE_CONNECT_PROTOCOL value is 0x08 (decimal 8), as in
   HTTP/2.

   If a server advertises support for Extended CONNECT but receives an
   Extended CONNECT request with a ":protocol" value that is unknown or
   is not supported, the server SHOULD respond to the request with a 501
   (Not Implemented) status code (Section 15.6.2 of [HTTP]).  A server
   MAY provide more information via a "problem details" response
   [RFC7807].

   The HTTP/3 stream closure is also analogous to the TCP connection
   closure of [RFC6455].  Orderly TCP-level closures are represented as
   a FIN bit on the stream (Section 4.4 of [HTTP/3]).  RST exceptions
   are represented with a stream error (Section 8 of [HTTP/3]) of type
   H3_REQUEST_CANCELLED (Section 8.1 of [HTTP/3]).

4.  Security Considerations

   This document introduces no new security considerations beyond those
   discussed in [RFC8441].

5.  IANA Considerations

   This document registers a new setting in the "HTTP/3 Settings"
   registry (Section 11.2.2 of [HTTP/3]).

   Value:  0x08
   Setting Name:  SETTINGS_ENABLE_CONNECT_PROTOCOL
   Default:  0
   Status:  permanent
   Specification:  This document
   Change Controller:  IETF
   Contact:  HTTP Working Group (ietf-http-wg@w3.org)

6.  Normative References

   [HTTP]     Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,
              Ed., "HTTP Semantics", STD 97, RFC 9110,
              DOI 10.17487/RFC9110, June 2022,
              <https://www.rfc-editor.org/info/rfc9110>.

   [HTTP/2]   Thomson, M., Ed. and C. Benfield, Ed., "HTTP/2", RFC 9113,
              DOI 10.17487/RFC9113, June 2022,
              <https://www.rfc-editor.org/info/rfc9113>.

   [HTTP/3]   Bishop, M., Ed., "HTTP/3", RFC 9114, DOI 10.17487/RFC9114,
              June 2022, <https://www.rfc-editor.org/info/rfc9114>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC6455]  Fette, I. and A. Melnikov, "The WebSocket Protocol",
              RFC 6455, DOI 10.17487/RFC6455, December 2011,
              <https://www.rfc-editor.org/info/rfc6455>.

   [RFC7807]  Nottingham, M. and E. Wilde, "Problem Details for HTTP
              APIs", RFC 7807, DOI 10.17487/RFC7807, March 2016,
              <https://www.rfc-editor.org/info/rfc7807>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC8441]  McManus, P., "Bootstrapping WebSockets with HTTP/2",
              RFC 8441, DOI 10.17487/RFC8441, September 2018,
              <https://www.rfc-editor.org/info/rfc8441>.

Acknowledgments

   This document had reviews and input from many contributors in the
   IETF HTTP and QUIC Working Groups, with substantive input from David
   Schinazi, Martin Thomson, Lucas Pardue, Mike Bishop, Dragana
   Damjanovic, Mark Nottingham, and Julian Reschke.

Author's Address

   Ryan Hamilton
   Google
   Email: rch@google.com

ISO Plain Language

On this page
PROBLEMThe WebSocket mechanism defined for HTTP/2 is also useful with HTTP/3, but its HTTP/3-specific details needed to be specified.
MECHANISMThe memo carries over Extended CONNECT semantics and registers the SETTINGS_ENABLE_CONNECT_PROTOCOL setting for HTTP/3.
WHAT IT SPECIFIESThe HTTP/3 setting is registered with value 0x08, and stream closure represents closure of the WebSocket transport stream.

§1Adapting the HTTP/2 Mechanism

RFC 8441 defines a way to run the WebSocket Protocol over a single stream of an HTTP/2 connection. RFC 9220 specifies how to use that mechanism with HTTP/3, where protocol settings must be registered separately.

HTTP/2 already had a way to carry WebSockets on one stream. This memo specifies the related details for HTTP/3.

§3Extended CONNECT and HTTP/3 Settings

Extended CONNECT uses a :protocol pseudo-header field and defines semantics for the :path and :authority pseudo-header fields. The meaning of these fields and the setting is identical to HTTP/2. The HTTP/3 setting SETTINGS_ENABLE_CONNECT_PROTOCOL has value 0x08, the same value used in HTTP/2.

If a server advertises Extended CONNECT but receives an unknown or unsupported :protocol value, it SHOULD respond with status 501 (Not Implemented). It MAY include more information in a problem-details response.

The client and server use Extended CONNECT to identify the WebSocket protocol on the stream. A server that does not support the requested protocol should return 501.

§3Closing the HTTP/3 Stream

HTTP/3 stream closure is analogous to TCP connection closure for WebSockets. An orderly closure is represented by a FIN bit on the stream. An RST exception is represented by an HTTP/3 stream error of type H3_REQUEST_CANCELLED.

The HTTP/3 stream has signals for normal and cancelled closure. These serve the corresponding roles of connection closure in the WebSocket protocol.

§5Security and Registration

The memo introduces no new security considerations beyond those in RFC 8441. IANA registers SETTINGS_ENABLE_CONNECT_PROTOCOL in the HTTP/3 Settings registry with value 0x08, default 0 and permanent status.

The RFC adds no security considerations beyond the earlier HTTP/2 specification. It records the setting and its default in the HTTP/3 registry.

§5References

[RFC8441]RFC 8441McManus, P., "Bootstrapping WebSockets with HTTP/2", RFC 8441, September 2018.September 2018[RFC6455]RFC 6455Fette, I. and A. Melnikov, "The WebSocket Protocol", RFC 6455, December 2011.December 2011[HTTP/3]RFC 9114Bishop, M., Ed., "HTTP/3", RFC 9114, June 2022.June 2022