Internet Engineering Task Force (IETF) M. Bishop
Request for Comments: 9412 Akamai
Category: Standards Track June 2023
ISSN: 2070-1721
The ORIGIN Extension in HTTP/3
Abstract
The ORIGIN frame for HTTP/2 is equally applicable to HTTP/3, but it
needs to be separately registered. This document describes the
ORIGIN frame 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/rfc9412.
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Table of Contents
1. Introduction
1.1. Notational Conventions
2. The ORIGIN HTTP/3 Frame
2.1. Frame Layout
3. Security Considerations
4. IANA Considerations
5. References
5.1. Normative References
5.2. Informative References
Author's Address
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.
1.1. Notational Conventions
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.
The frame diagram in this document uses the format defined in
Section 1.3 of [QUIC-TRANSPORT] to illustrate the order and size of
fields.
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.
2.1. Frame Layout
The ORIGIN frame has a layout that is nearly identical to the layout
used in HTTP/2; the information is restated here for clarity. The
ORIGIN frame type is 0x0c (decimal 12), as in HTTP/2. The payload
contains zero or more instances of the Origin-Entry field.
HTTP/3 Origin-Entry {
Origin-Len (16),
ASCII-Origin (..),
}
HTTP/3 ORIGIN Frame {
Type (i) = 0x0c,
Length (i),
Origin-Entry (..) ...,
}
Figure 1: ORIGIN Frame Layout
An Origin-Entry is a length-delimited string. Specifically, it
contains two fields:
Origin-Len: An unsigned, 16-bit integer indicating the length, in
octets, of the ASCII-Origin field.
ASCII-Origin: An OPTIONAL sequence of characters containing the
ASCII serialization of an origin ([RFC6454], Section 6.2) that the
sender asserts this connection is or could be authoritative for.
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>
5. References
5.1. Normative References
[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>.
[ORIGIN] Nottingham, M. and E. Nygren, "The ORIGIN HTTP/2 Frame",
RFC 8336, DOI 10.17487/RFC8336, March 2018,
<https://www.rfc-editor.org/info/rfc8336>.
[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>.
[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>.
5.2. Informative References
[QUIC-TRANSPORT]
Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based
Multiplexed and Secure Transport", RFC 9000,
DOI 10.17487/RFC9000, May 2021,
<https://www.rfc-editor.org/info/rfc9000>.
[RFC6454] Barth, A., "The Web Origin Concept", RFC 6454,
DOI 10.17487/RFC6454, December 2011,
<https://www.rfc-editor.org/info/rfc6454>.
Author's Address
Mike Bishop
Akamai
Email: mbishop@evequefou.be