RFC 9412: The ORIGIN Extension in 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/rfc9412.¶

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1. Introduction

Existing RFCs define extensions to HTTP/2 [HTTP/2] that remain useful in HTTP/3. Appendix A.2 of [HTTP/3] describes the required updates for HTTP/2 frames to be used with HTTP/3.¶

[ORIGIN] defines the HTTP/2 ORIGIN frame, which indicates what origins are available on a given connection. It defines a single HTTP/2 frame type.¶

2. The ORIGIN HTTP/3 Frame

The ORIGIN HTTP/3 frame allows a server to indicate what origin or origins [RFC6454] the server would like the client to consider as one or more members of the Origin Set (Section 2.3 of [ORIGIN]) for the connection within which it occurs.¶

The semantics of the frame payload are identical to those of the HTTP/2 frame defined in [ORIGIN]. Where HTTP/2 reserves stream 0 for frames related to the state of the connection, HTTP/3 defines a pair of unidirectional streams called "control streams" for this purpose.¶

Where [ORIGIN] indicates that the ORIGIN frame is sent on stream 0, this should be interpreted to mean the HTTP/3 control stream: that is, the ORIGIN frame is sent from servers to clients on the server's control stream.¶

HTTP/3 does not define a Flags field in the generic frame layout. As no flags have been defined for the ORIGIN frame, this specification does not define a mechanism for communicating such flags in HTTP/3.¶

HTTP/3 Origin-Entry {
  Origin-Len (16),
  ASCII-Origin (..),
}

HTTP/3 ORIGIN Frame {
  Type (i) = 0x0c,
  Length (i),
  Origin-Entry (..) ...,
}

3. Security Considerations

This document introduces no new security considerations beyond those discussed in [ORIGIN] and [HTTP/3].¶

4. IANA Considerations

This document registers a frame type in the "HTTP/3 Frame Types" registry defined by [HTTP/3], located at <https://www.iana.org/assignments/http3-parameters/>.¶

Value:

0x0c¶

Frame Type:

ORIGIN¶

Status:

permanent¶

Reference:

Section 2¶

Date:

2023-03-14¶

Change Controller:

IETF¶

Contact:

HTTP WG <ietf-http-wg@w3.org>¶

Author's Address