< draft-ietf-httpbis-origin-frame-00.txt		draft-ietf-httpbis-origin-frame-01.txt >
	HTTP Working Group M. Nottingham		HTTP Working Group M. Nottingham
	Internet-Draft E. Nygren		Internet-Draft E. Nygren
	Intended status: Standards Track Akamai		Intended status: Standards Track Akamai
	Expires: November 11, 2016 May 10, 2016		Expires: April 1, 2017 September 28, 2016
	The ORIGIN HTTP/2 Frame		The ORIGIN HTTP/2 Frame
	draft-ietf-httpbis-origin-frame-00		draft-ietf-httpbis-origin-frame-01
	Abstract		Abstract
	This document specifies the ORIGIN frame for HTTP/2, to indicate what		This document specifies the ORIGIN frame for HTTP/2, to indicate what
	origins are available on a given connection.		origins are available on a given connection.
			Note to Readers
			Discussion of this draft takes place on the HTTP working group
			mailing list (ietf-http-wg@w3.org), which is archived at
			https://lists.w3.org/Archives/Public/ietf-http-wg/ .
			Working Group information can be found at http://httpwg.github.io/ ;
			source code and issues list for this draft can be found at
			https://github.com/httpwg/http-extensions/labels/origin-frame .
	Status of This Memo		Status of This Memo
	This Internet-Draft is submitted in full conformance with the		This Internet-Draft is submitted in full conformance with the
	provisions of BCP 78 and BCP 79.		provisions of BCP 78 and BCP 79.
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	Copyright Notice		Copyright Notice
	Copyright (c) 2016 IETF Trust and the persons identified as the		Copyright (c) 2016 IETF Trust and the persons identified as the
	document authors. All rights reserved.		document authors. All rights reserved.
	This document is subject to BCP 78 and the IETF Trust's Legal		This document is subject to BCP 78 and the IETF Trust's Legal
	Provisions Relating to IETF Documents		Provisions Relating to IETF Documents
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	carefully, as they describe your rights and restrictions with respect		carefully, as they describe your rights and restrictions with respect
	to this document. Code Components extracted from this document must		to this document. Code Components extracted from this document must
	include Simplified BSD License text as described in Section 4.e of		include Simplified BSD License text as described in Section 4.e of
	the Trust Legal Provisions and are provided without warranty as		the Trust Legal Provisions and are provided without warranty as
	described in the Simplified BSD License.		described in the Simplified BSD License.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
	1.1. Notational Conventions . . . . . . . . . . . . . . . . . 2		1.1. Notational Conventions . . . . . . . . . . . . . . . . . 2
	1.2. The ORIGIN HTTP/2 Frame . . . . . . . . . . . . . . . . . 2		2. The ORIGIN HTTP/2 Frame . . . . . . . . . . . . . . . . . . . 2
	2. Security Considerations . . . . . . . . . . . . . . . . . . . 3		2.1. The Origin Set . . . . . . . . . . . . . . . . . . . . . 3
	3. Normative References . . . . . . . . . . . . . . . . . . . . 3		2.2. Processing ORIGIN Frames . . . . . . . . . . . . . . . . 4
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 4		3. Security Considerations . . . . . . . . . . . . . . . . . . . 5
			4. Normative References . . . . . . . . . . . . . . . . . . . . 5
			Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
	1. Introduction		1. Introduction
	HTTP/2 [RFC7540] allows clients to coalesce different origins		HTTP/2 [RFC7540] allows clients to coalesce different origins
	[RFC6454] onto the same connection when certain conditions are met.		[RFC6454] onto the same connection when certain conditions are met.
	In some cases, the server is not authoritative for a coalesced		However, in certain cases, a connection is is not usable for a
	origin, so the 421 (Misdirected Request) status code was defined.		coalesced origin, so the 421 (Misdirected Request) status code
			([RFC7540], Section 9.1.2) was defined.
	Using a status code in this manner allows clients to recover from		Using a status code in this manner allows clients to recover from
	misdirected requests, but at the penalty of adding latency. To		misdirected requests, but at the penalty of adding latency. To
	address that, this specification defines a new HTTP/2 frame type,		address that, this specification defines a new HTTP/2 frame type,
	"ORIGIN", to allow servers to indicate what origins a connection is		"ORIGIN", to allow servers to indicate what origins a connection is
	authoritative for.		usable for.
	1.1. Notational Conventions		1.1. Notational Conventions
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this		"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
	document are to be interpreted as described in [RFC2119].		document are to be interpreted as described in [RFC2119].
	1.2. The ORIGIN HTTP/2 Frame		2. The ORIGIN HTTP/2 Frame
	The ORIGIN HTTP/2 frame ([RFC7540], Section 4) indicates what		The ORIGIN HTTP/2 frame ([RFC7540], Section 4) allows a server to
	origin(s) [RFC6454] the sender considers this connection		indicate what origin(s) [RFC6454] the server would like the client to
	authoritative for (in the sense of [RFC7540], Section 10.1).		consider as members of the Origin Set (Section 2.1) for the
			connection it occurs within.
	The ORIGIN frame is a non-critical extension to HTTP/2. Endpoints		The ORIGIN frame type is 0xb (decimal 11).
	that do not support this frame can safely ignore it.
	It MUST occur on stream 0; an ORIGIN frame on any other stream is		+-------------------------------+-------------------------------+
	invalid and MUST be ignored.		| Origin-Len (16) | Origin? (*) ...
			+-------------------------------+-------------------------------+
			The ORIGIN frame's payload contains the following fields, sets of
			which may be repeated within the frame to indicate multiple origins:
			Origin-Len: An unsigned, 16-bit integer indicating the length, in
			octets, of the Origin field.
			Origin: An optional sequence of characters containing the ASCII
			serialization of an origin ([RFC6454], Section 6.2) that the
			sender believes this connection is or could be authoritative for.
			The ORIGIN frame defines the following flags:
			CLEAR (0x1): Indicates that the Origin Set MUST be reset to an empty
			set before processing the contents of the frame it occurs upon.
			REMOVE (0x2): Indicates that the origin(s) carried in the payload
			must be removed from the Origin Set, if present; if not present,
			it/they have no effect.
			2.1. The Origin Set
			The set of origins (as per [RFC6454]) that a given connection might
			be used for is known in this specification as the Origin Set.
			When a connection is first established, its Origin Set is defined to
			be those origins that the client would normally consider the
			connection authoritative for; see [RFC7540], Section 10.1.
			The ORIGIN frame allows the server to modify the Origin Set. In
			particular:
			1. A server can add to its members by sending an ORIGIN frame
			(without any flags set);
			2. A server can prune one or more origins from it by sending an
			ORIGIN frame with the REMOVE flag set;
			3. A server can remove all its members and then add zero or more
			members by sending an ORIGIN frame with the CLEAR flag set and a
			payload containing the new origins.
			Adding to the Origin Set (cases 1 and 3 above) does not imply that
			the connection is authoritative for the added origins (in the sense
			of [RFC7540], Section 10.1) on its own; this MUST be established by
			some other mechanism.
			A client that implements this specification MUST NOT use a connection
			for a given origin unless that origin appears in the Origin Set for
			the connection, regardless of whether or not it believes that the
			connection is authoritative for that origin.
			2.2. Processing ORIGIN Frames
			The ORIGIN frame is a non-critical extension to HTTP/2. Endpoints
			that do not support this frame can safely ignore it upon receipt.
	When received by a client, it can be used to inform HTTP/2 connection		When received by a client, it can be used to inform HTTP/2 connection
	coalescing (see [RFC7540], Section 9.1.1), but does not relax the		coalescing (see Section 2.1), but does not relax the requirement
	requirement there that the server is authoritative.		there that the server is authoritative.
	If multiple ORIGIN frames are received on the same connection, only		The origin frame MUST be sent on stream 0; an ORIGIN frame on any
	the most recent is to be considered current.		other stream is invalid and MUST be ignored.
	Once an ORIGIN frame has been received and processed, clients that		The ORIGIN frame is processed hop-by-hop. An intermediary MUST NOT
	implement this specification SHOULD NOT use that connection for a		forward ORIGIN frames. Clients configured to use a proxy MUST ignore
	given origin if it did not appear within the current ORIGIN frame.		any ORIGIN frames received from it.
	The ORIGIN frame type is 0xb (decimal 11).		The following algorithm illustrates how a client can handle received
			ORIGIN frames:
	+-------------------------------+-------------------------------+		1. If the client is configured to use a proxy, ignore the frame and
	| Origin-Len (16) | Origin? (*) ...		stop processing.
	+-------------------------------+-------------------------------+
	The ORIGIN frame contains the following fields, sets of which may be		2. If the frame occurs upon any stream except stream 0, ignore the
	repeated within the frame to indicate multiple origins:		frame and stop processing.
	Origin-Len: An unsigned, 16-bit integer indicating the length, in		3. If the CLEAR flag is set, remove all members from the Origin Set.
	octets, of the Origin field. Origin: An optional sequence of
	characters containing the ASCII serialization of an origin
	([RFC6454], Section 6.2) that the sender believes this connection is
	authoritative for.
	The ORIGIN frame does not define any flags. It can contain one or		4. For each Origin field "origin_raw" in the frame payload:
	more Origin-Len/Origin pairs.
	The ORIGIN frame is processed hop-by-hop. An intermediary must not		1. Parse "origin_raw" as an ASCII serialization of an origin
	forward ORIGIN frames.		([RFC6454], Section 6.2) and let the result be
			"parsed_origin".
	Clients configured to use a proxy MUST ignore any ORIGIN frames		2. If the REMOVE flag is set, remove any member of the Origin
	received from it.		Set that is the same as "parsed_origin" (as per [RFC6454],
			Section 5), and continue to the next "parsed_origin".
	2. Security Considerations		3. Otherwise, add "parsed_origin" to the Origin Set.
			3. Security Considerations
	Clients that blindly trust the ORIGIN frame's contents will be		Clients that blindly trust the ORIGIN frame's contents will be
	vulnerable to a large number of attacks; hence the reinforcement that		vulnerable to a large number of attacks; hence the reinforcement that
	this specification does not relax the requirement for server		this specification does not relax the requirement for server
	authority in [RFC7540], Section 10.1.		authority in [RFC7540], Section 10.1.
	3. Normative References		4. Normative References
	[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate		[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
	Requirement Levels", BCP 14, RFC 2119,		Requirement Levels", BCP 14, RFC 2119,
	DOI 10.17487/RFC2119, March 1997,		DOI 10.17487/RFC2119, March 1997,
	<http://www.rfc-editor.org/info/rfc2119>.		<http://www.rfc-editor.org/info/rfc2119>.
	[RFC6454] Barth, A., "The Web Origin Concept", RFC 6454,		[RFC6454] Barth, A., "The Web Origin Concept", RFC 6454,
	DOI 10.17487/RFC6454, December 2011,		DOI 10.17487/RFC6454, December 2011,
	<http://www.rfc-editor.org/info/rfc6454>.		<http://www.rfc-editor.org/info/rfc6454>.
	skipping to change at page 4, line 16 ¶		skipping to change at page 5, line 34 ¶
	Transfer Protocol Version 2 (HTTP/2)", RFC 7540,		Transfer Protocol Version 2 (HTTP/2)", RFC 7540,
	DOI 10.17487/RFC7540, May 2015,		DOI 10.17487/RFC7540, May 2015,
	<http://www.rfc-editor.org/info/rfc7540>.		<http://www.rfc-editor.org/info/rfc7540>.
	Authors' Addresses		Authors' Addresses
	Mark Nottingham		Mark Nottingham
	Akamai		Akamai
	Email: mnot@mnot.net		Email: mnot@mnot.net
	URI: http://www.mnot.net/		URI: https://www.mnot.net/
	Erik Nygren		Erik Nygren
	Akamai		Akamai
	Email: nygren@akamai.com		Email: nygren@akamai.com
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