< draft-ietf-httpbis-origin-frame-04.txt		draft-ietf-httpbis-origin-frame-05.txt >
	HTTP Working Group M. Nottingham		HTTP M. Nottingham
	Internet-Draft		Internet-Draft
	Intended status: Standards Track E. Nygren		Intended status: Standards Track E. Nygren
	Expires: February 24, 2018 Akamai		Expires: July 15, 2018 Akamai
	August 23, 2017		January 11, 2018
	The ORIGIN HTTP/2 Frame		The ORIGIN HTTP/2 Frame
	draft-ietf-httpbis-origin-frame-04		draft-ietf-httpbis-origin-frame-05
	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		Note to Readers
	Discussion of this draft takes place on the HTTP working group		Discussion of this draft takes place on the HTTP working group
	mailing list (ietf-http-wg@w3.org), which is archived at		mailing list (ietf-http-wg@w3.org), which is archived at
	https://lists.w3.org/Archives/Public/ietf-http-wg/.		https://lists.w3.org/Archives/Public/ietf-http-wg/ [1].
	Working Group information can be found at http://httpwg.github.io/;		Working Group information can be found at http://httpwg.github.io/
	source code and issues list for this draft can be found at		[2]; source code and issues list for this draft can be found at
	https://github.com/httpwg/http-extensions/labels/origin-frame.		https://github.com/httpwg/http-extensions/labels/origin-frame [3].
	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.
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF). Note that other groups may also distribute		Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-		working documents as Internet-Drafts. The list of current Internet-
	Drafts is at http://datatracker.ietf.org/drafts/current/.		Drafts is at https://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		Internet-Drafts are draft documents valid for a maximum of six months
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
	time. It is inappropriate to use Internet-Drafts as reference		time. It is inappropriate to use Internet-Drafts as reference
	material or to cite them other than as "work in progress."		material or to cite them other than as "work in progress."
	This Internet-Draft will expire on February 24, 2018.		This Internet-Draft will expire on July 15, 2018.
	Copyright Notice		Copyright Notice
	Copyright (c) 2017 IETF Trust and the persons identified as the		Copyright (c) 2018 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
	(http://trustee.ietf.org/license-info) in effect on the date of		(https://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents		publication of this document. Please review these documents
	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 . . . . . . . . . . . . . . . . . 3		1.1. Notational Conventions . . . . . . . . . . . . . . . . . 3
	2. The ORIGIN HTTP/2 Frame . . . . . . . . . . . . . . . . . . . 3		2. The ORIGIN HTTP/2 Frame . . . . . . . . . . . . . . . . . . . 3
	2.1. Syntax . . . . . . . . . . . . . . . . . . . . . . . . . 3		2.1. Syntax . . . . . . . . . . . . . . . . . . . . . . . . . 3
	2.2. Processing ORIGIN Frames . . . . . . . . . . . . . . . . 3		2.2. Processing ORIGIN Frames . . . . . . . . . . . . . . . . 4
	2.3. The Origin Set . . . . . . . . . . . . . . . . . . . . . 4		2.3. The Origin Set . . . . . . . . . . . . . . . . . . . . . 5
	2.4. Authority, Push and Coalescing with ORIGIN . . . . . . . 5		2.4. Authority, Push and Coalescing with ORIGIN . . . . . . . 6
	3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6		3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
	4. Security Considerations . . . . . . . . . . . . . . . . . . . 6		4. Security Considerations . . . . . . . . . . . . . . . . . . . 7
	5. References . . . . . . . . . . . . . . . . . . . . . . . . . 7		5. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
	5.1. Normative References . . . . . . . . . . . . . . . . . . 7		5.1. Normative References . . . . . . . . . . . . . . . . . . 7
	5.2. Informative References . . . . . . . . . . . . . . . . . 8		5.2. Informative References . . . . . . . . . . . . . . . . . 8
	Appendix A. Non-Normative Processing Algorithm . . . . . . . . . 8		5.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 9
			Appendix A. Non-Normative Processing Algorithm . . . . . . . . . 9
	Appendix B. Operational Considerations for Servers . . . . . . . 9		Appendix B. Operational Considerations for Servers . . . . . . . 9
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
	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.
	However, in certain cases, a connection is not usable for a coalesced		However, in certain cases, a connection is not usable for a coalesced
	origin, so the 421 (Misdirected Request) status code ([RFC7540],		origin, so the 421 (Misdirected Request) status code ([RFC7540],
	Section 9.1.2) was defined.		Section 9.1.2) was defined.
	skipping to change at page 3, line 8 ¶		skipping to change at page 3, line 10 ¶
	Additionally, experience has shown that HTTP/2's requirement to		Additionally, experience has shown that HTTP/2's requirement to
	establish server authority using both DNS and the server's		establish server authority using both DNS and the server's
	certificate is onerous. This specification relaxes the requirement		certificate is onerous. This specification relaxes the requirement
	to check DNS when the ORIGIN frame is in use. Doing so has		to check DNS when the ORIGIN frame is in use. Doing so has
	additional benefits, such as removing the latency associated with		additional benefits, such as removing the latency associated with
	some DNS lookups.		some DNS lookups.
	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", "NOT RECOMMENDED", "MAY", and
	document are to be interpreted as described in [RFC2119].		"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.
	2. The ORIGIN HTTP/2 Frame		2. The ORIGIN HTTP/2 Frame
	The ORIGIN HTTP/2 frame ([RFC7540], Section 4) allows a server to		This document defines a new HTTP/2 frame type ([RFC7540], Section 4)
	indicate what origin(s) [RFC6454] the server would like the client to		called ORIGIN, that allows a server to indicate what origin(s)
	consider as members of the Origin Set (Section 2.3) for the		[RFC6454] the server would like the client to consider as members of
	connection it occurs within.		the Origin Set (Section 2.3) for the connection it occurs within.
	2.1. Syntax		2.1. Syntax
	The ORIGIN frame type is 0xc (decimal 12), and contains zero to many		The ORIGIN frame type is 0xc (decimal 12), and contains zero or more
	Origin-Entry.		instances of the Origin-Entry field.
	+-------------------------------+-------------------------------+		+-------------------------------+-------------------------------+
	| Origin-Entry (*) ...		| Origin-Entry (*) ...
	+-------------------------------+-------------------------------+		+-------------------------------+-------------------------------+
	An Origin-Entry is a length-delimited string:		An Origin-Entry is a length-delimited string:
	+-------------------------------+-------------------------------+		+-------------------------------+-------------------------------+
	| Origin-Len (16) | ASCII-Origin? ...		| Origin-Len (16) | ASCII-Origin? ...
	+-------------------------------+-------------------------------+		+-------------------------------+-------------------------------+
	Specifically:		Specifically:
	Origin-Len: An unsigned, 16-bit integer indicating the length, in		Origin-Len: An unsigned, 16-bit integer indicating the length, in
	octets, of the ASCII-Origin field.		octets, of the ASCII-Origin field.
	Origin: An OPTIONAL sequence of characters containing the ASCII		Origin: An OPTIONAL sequence of characters containing the ASCII
	serialization of an origin ([RFC6454], Section 6.2) that the		serialization of an origin ([RFC6454], Section 6.2) that the
	sender believes this connection is or could be authoritative for.		sender asserts this connection is or could be authoritative for.
	The ORIGIN frame does not define any flags. However, future updates		The ORIGIN frame does not define any flags. However, future updates
	to this specification MAY define flags. See Section 2.2.		to this specification MAY define flags. See Section 2.2.
	2.2. Processing ORIGIN Frames		2.2. Processing ORIGIN Frames
	The ORIGIN frame is a non-critical extension to HTTP/2. Endpoints		The ORIGIN frame is a non-critical extension to HTTP/2. Endpoints
	that do not support this frame can safely ignore it upon receipt.		that do not support this frame can safely ignore it upon receipt.
	When received by an implementing client, it is used to initialise and		When received by an implementing client, it is used to initialise and
	manipulate the Origin Set (see Section 2.3), thereby changing how the		manipulate the Origin Set (see Section 2.3), thereby changing how the
	client establishes authority for origin servers (see Section 2.4).		client establishes authority for origin servers (see Section 2.4).
	The origin frame MUST be sent on stream 0; an ORIGIN frame on any		The ORIGIN frame MUST be sent on stream 0; an ORIGIN frame on any
	other stream is invalid and MUST be ignored.		other stream is invalid and MUST be ignored.
	Likewise, the ORIGIN frame is only valid on connections with the "h2"		Likewise, the ORIGIN frame is only valid on connections with the "h2"
	protocol identifier, or when specifically nominated by the protocol's		protocol identifier, or when specifically nominated by the protocol's
	definition; it MUST be ignored when received on a connection with the		definition; it MUST be ignored when received on a connection with the
	"h2c" protocol identifier.		"h2c" protocol identifier.
	This specification does not define any flags for the ORIGIN frame,		This specification does not define any flags for the ORIGIN frame,
	but future updates might use them to change its semantics. The first		but future updates to this specification (through IETF consensus)
	four flags (0x1, 0x2, 0x4 and 0x8) are reserved for backwards-		might use them to change its semantics. The first four flags (0x1,
	incompatible changes, and therefore when any of them are set, the		0x2, 0x4 and 0x8) are reserved for backwards-incompatible changes,
	ORIGIN frame containing them MUST be ignored by clients conforming to		and therefore when any of them are set, the ORIGIN frame containing
	this specification, unless the flag's semantics are understood. The		them MUST be ignored by clients conforming to this specification,
	remaining flags are reserved for backwards-compatible changes, and do		unless the flag's semantics are understood. The remaining flags are
	not affect processing by clients conformant to this specification.		reserved for backwards-compatible changes, and do not affect
			processing by clients conformant to this specification.
	The ORIGIN frame describes a property of the connection, and		The ORIGIN frame describes a property of the connection, and
	therefore is processed hop-by-hop. An intermediary MUST NOT forward		therefore is processed hop-by-hop. An intermediary MUST NOT forward
	ORIGIN frames. Clients configured to use a proxy MUST ignore any		ORIGIN frames. Clients configured to use a proxy MUST ignore any
	ORIGIN frames received from it.		ORIGIN frames received from it.
	Each ASCII-Origin field in the frame's payload MUST be parsed as an		Each ASCII-Origin field in the frame's payload MUST be parsed as an
	ASCII serialisation of an origin ([RFC6454], Section 6.2). If		ASCII serialisation of an origin ([RFC6454], Section 6.2). If
	parsing fails, the field MUST be ignored.		parsing fails, the field MUST be ignored.
			Note that the ORIGIN frame does not support wildcard names (e.g.,
			"*.example.com") in Origin-Entry. As a result, sending ORIGIN when a
			wildcard certificate is in use effectively disables any origins that
			are not explicitly listed in the ORIGIN frame(s) (when the client
			understands ORIGIN).
	See Appendix A for an illustrative algorithm for processing ORIGIN		See Appendix A for an illustrative algorithm for processing ORIGIN
	frames.		frames.
	2.3. The Origin Set		2.3. The Origin Set
	The set of origins (as per [RFC6454]) that a given connection might		The set of origins (as per [RFC6454]) that a given connection might
	be used for is known in this specification as the Origin Set.		be used for is known in this specification as the Origin Set.
	By default, the Origin Set for a connection is uninitialised. When		By default, the Origin Set for a connection is uninitialised. When
	an ORIGIN frame is first received and successfully processed by a		an ORIGIN frame is first received and successfully processed by a
	client, the connection's Origin Set is defined to contain an initial		client, the connection's Origin Set is defined to contain an initial
	origin. The initial origin is composed from:		origin. The initial origin is composed from:
	o Scheme: "https"		o Scheme: "https"
	o Host: the value sent in Server Name Indication (SNI, [RFC6066]		o Host: the value sent in Server Name Indication (SNI, [RFC6066],
	Section 3), converted to lower case		Section 3), converted to lower case; if SNI is not present, the
			remote address of the connection (i.e., the server's IP address)
	o Port: the remote port of the connection (i.e., the server's port)		o Port: the remote port of the connection (i.e., the server's port)
	The contents of that ORIGIN frame (and subsequent ones) allows the		The contents of that ORIGIN frame (and subsequent ones) allows the
	server to incrementally add new origins to the Origin Set, as		server to incrementally add new origins to the Origin Set, as
	described in Section 2.2.		described in Section 2.2.
	The Origin Set is also affected by the 421 (Misdirected Request)		The Origin Set is also affected by the 421 (Misdirected Request)
	response status code, defined in [RFC7540] Section 9.1.2. Upon		response status code, defined in [RFC7540], Section 9.1.2. Upon
	receipt of a response with this status code, implementing clients		receipt of a response with this status code, implementing clients
	MUST create the ASCII serialisation of the corresponding request's		MUST create the ASCII serialisation of the corresponding request's
	origin (as per [RFC6454], Section 6.2) and remove it from the		origin (as per [RFC6454], Section 6.2) and remove it from the
	connection's Origin Set, if present.		connection's Origin Set, if present.
	Note: When sending an ORIGIN frame to a connection that is		Note: When sending an ORIGIN frame to a connection that is
	initialised as an Alternative Service [RFC7838], the initial		initialised as an Alternative Service [RFC7838], the initial
	origin set Section 2.3 will contain an origin with the appropriate		origin set (Section 2.3) will contain an origin with the
	scheme and hostname (since Alternative Services specifies that the		appropriate scheme and hostname (since Alternative Services
	origin's hostname be sent in SNI). However, it is possible that		specifies that the origin's hostname be sent in SNI). However, it
	the port will be different than that of the intended origin, since		is possible that the port will be different than that of the
	the initial origin set is calculated using the actual port in use,		intended origin, since the initial origin set is calculated using
	which can be different for the alternative service. In this case,		the actual port in use, which can be different for the alternative
	the intended origin needs to be sent in the ORIGIN frame		service. In this case, the intended origin needs to be sent in
	explicitly.		the ORIGIN frame explicitly.
	For example, a client making requests for "https://example.com" is		For example, a client making requests for "https://example.com" is
	directed to an alternative service at ("h2", "x.example.net",		directed to an alternative service at ("h2", "x.example.net",
	"8443"). If this alternative service sends an ORIGIN frame, the		"8443"). If this alternative service sends an ORIGIN frame, the
	initial origin will be "https://example.com:8443". The client		initial origin will be "https://example.com:8443". The client
	will not be able to use the alternative service to make requests		will not be able to use the alternative service to make requests
	for "https://example.com" unless that origin is explicitly		for "https://example.com" unless that origin is explicitly
	included in the ORIGIN frame.		included in the ORIGIN frame.
	2.4. Authority, Push and Coalescing with ORIGIN		2.4. Authority, Push and Coalescing with ORIGIN
	[RFC7540], Section 10.1 uses both DNS and the presented TLS		Section 10.1 of [RFC7540] uses both DNS and the presented TLS
	certificate to establish the origin server(s) that a connection is		certificate to establish the origin server(s) that a connection is
	authoritative for, just as HTTP/1.1 does in [RFC7230].		authoritative for, just as HTTP/1.1 does in [RFC7230].
	Furthermore, [RFC7540] Section 9.1.1 explicitly allows a connection		Furthermore, Section 9.1.1 of [RFC7540] explicitly allows a
	to be used for more than one origin server, if it is authoritative.		connection to be used for more than one origin server, if it is
	This affects what requests can be sent on the connection, both in		authoritative. This affects what responses can be considered
	HEADERS frame by the client and as PUSH_PROMISE frames from the		authoritative, both for direct responses to requests and for server
	server ([RFC7540], Section 8.2.2).		push (see [RFC7540], Section 8.2.2). Indirectly, it also affects
			what requests will be sent on a connection, since clients will
			generally only send requests on connections that they believe to be
			authoritative for the origin in question.
	Once an Origin Set has been initialised for a connection, clients		Once an Origin Set has been initialised for a connection, clients
	that implement this specification use it to help determine what the		that implement this specification use it to help determine what the
	connection is authoritative for. Specifically, such clients MUST NOT		connection is authoritative for. Specifically, such clients MUST NOT
	consider a connection to be authoritative for an origin not present		consider a connection to be authoritative for an origin not present
	in the Origin Set, and SHOULD use the connection for all requests to		in the Origin Set, and SHOULD use the connection for all requests to
	origins in the Origin Set for which the connection is authoritative,		origins in the Origin Set for which the connection is authoritative,
	unless there are operational reasons for opening a new connection.		unless there are operational reasons for opening a new connection.
	Note that for a connection to be considered authoritative for a given		Note that for a connection to be considered authoritative for a given
	origin, the client is still required to obtain a certificate that		origin, the server is still required to authenticate with certificate
	passes suitable checks; see [RFC7540] Section 9.1.1 for more		that passes suitable checks; see Section 9.1.1 of [RFC7540] for more
	information. This includes verifying that the host matches a		information. This includes verifying that the host matches a
	"dNSName" value from the certificate "subjectAltName" field (using		"dNSName" value from the certificate "subjectAltName" field (using
	the wildcard rules defined in [RFC2818]; see also [RFC5280]		the rules defined in [RFC2818]; see also [RFC5280], Section 4.2.1.6).
	Section 4.2.1.6).
	Additionally, clients MAY avoid consulting DNS to establish the		Additionally, clients MAY avoid consulting DNS to establish the
	connection's authority for new requests; however, those that do so		connection's authority for new requests to origins in the Origin Set;
	face new risks, as explained in Section 4		however, those that do so face new risks, as explained in Section 4.
	Because ORIGIN can change the set of origins a connection is used for		Because ORIGIN can change the set of origins a connection is used for
	over time, it is possible that a client might have more than one		over time, it is possible that a client might have more than one
	viable connection to an origin open at any time. When this occurs,		viable connection to an origin open at any time. When this occurs,
	clients SHOULD not emit new requests on any connection whose Origin		clients SHOULD NOT emit new requests on any connection whose Origin
	Set is a proper subset of another connection's Origin Set, and SHOULD		Set is a proper subset of another connection's Origin Set, and SHOULD
	close it once all outstanding requests are satisfied.		close it once all outstanding requests are satisfied.
	The Origin Set is unaffected by any alternative services [RFC7838]		The Origin Set is unaffected by any alternative services [RFC7838]
	advertisements made by the server. Advertising an alternative		advertisements made by the server. Advertising an alternative
	service does not affect whether a server is authoritative.		service does not affect whether a server is authoritative.
	3. IANA Considerations		3. IANA Considerations
	This specification adds an entry to the "HTTP/2 Frame Type" registry.		This specification adds an entry to the "HTTP/2 Frame Type" registry.
	skipping to change at page 7, line 6 ¶		skipping to change at page 7, line 29 ¶
	mitigations.		mitigations.
	Relaxing the requirement to consult DNS when determining authority		Relaxing the requirement to consult DNS when determining authority
	for an origin means that an attacker who possesses a valid		for an origin means that an attacker who possesses a valid
	certificate no longer needs to be on-path to redirect traffic to		certificate no longer needs to be on-path to redirect traffic to
	them; instead of modifying DNS, they need only convince the user to		them; instead of modifying DNS, they need only convince the user to
	visit another Web site in order to coalesce connections to the target		visit another Web site in order to coalesce connections to the target
	onto their existing connection.		onto their existing connection.
	As a result, clients opting not to consult DNS ought to employ some		As a result, clients opting not to consult DNS ought to employ some
	alternative means to increase confidence that the certificate is		alternative means to establish a high degree of confidence that the
	legitimate. Examples of mechanisms that can give additional		certificate is legitimate. For example, clients might skip
	confidence in a certificate include checking for a Signed Certificate		consulting DNS only if they receive proof of inclusion in a
	Timestamp [RFC6929] and performing certificate revocation checks.		Certificate Transparency log [RFC6962] or they have a recent OCSP
			response [RFC6960] (possibly using the "status_request" TLS extension
	Clients opting not to consult DNS ought to do so only if they have a		[RFC6066]) showing that the certificate was not revoked.
	high degree of confidence that the certificate is legitimate. For
	instance, clients might skip consulting DNS only if they receive
	proof of inclusion in a Certificate Transparency log [RFC6929] or
	they have a recent OCSP response [RFC6960] (possibly using the
	"status_request" TLS extension [RFC6066]) showing that the
	certificate was not revoked.
	The Origin Set's size is unbounded by this specification, and thus		The Origin Set's size is unbounded by this specification, and thus
	could be used by attackers to exhaust client resources. To mitigate		could be used by attackers to exhaust client resources. To mitigate
	this risk, clients can monitor their state commitment and close the		this risk, clients can monitor their state commitment and close the
	connection if it is too high.		connection if it is too high.
	5. References		5. References
	5.1. Normative References		5.1. 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, <https://www.rfc-		DOI 10.17487/RFC2119, March 1997,
	editor.org/info/rfc2119>.		<https://www.rfc-editor.org/info/rfc2119>.
	[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818,		[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818,
	DOI 10.17487/RFC2818, May 2000, <https://www.rfc-		DOI 10.17487/RFC2818, May 2000,
	editor.org/info/rfc2818>.		<https://www.rfc-editor.org/info/rfc2818>.
	[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,		[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
	Housley, R., and W. Polk, "Internet X.509 Public Key		Housley, R., and W. Polk, "Internet X.509 Public Key
	Infrastructure Certificate and Certificate Revocation List		Infrastructure Certificate and Certificate Revocation List
	(CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,		(CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
	<https://www.rfc-editor.org/info/rfc5280>.		<https://www.rfc-editor.org/info/rfc5280>.
	[RFC6066] Eastlake 3rd, D., "Transport Layer Security (TLS)		[RFC6066] Eastlake 3rd, D., "Transport Layer Security (TLS)
	Extensions: Extension Definitions", RFC 6066,		Extensions: Extension Definitions", RFC 6066,
	DOI 10.17487/RFC6066, January 2011, <https://www.rfc-		DOI 10.17487/RFC6066, January 2011,
	editor.org/info/rfc6066>.		<https://www.rfc-editor.org/info/rfc6066>.
	[RFC6454] Barth, A., "The Web Origin Concept", RFC 6454,		[RFC6454] Barth, A., "The Web Origin Concept", RFC 6454,
	DOI 10.17487/RFC6454, December 2011, <https://www.rfc-		DOI 10.17487/RFC6454, December 2011,
	editor.org/info/rfc6454>.		<https://www.rfc-editor.org/info/rfc6454>.
	[RFC7540] Belshe, M., Peon, R., and M. Thomson, Ed., "Hypertext		[RFC7540] Belshe, M., Peon, R., and M. Thomson, Ed., "Hypertext
	Transfer Protocol Version 2 (HTTP/2)", RFC 7540,		Transfer Protocol Version 2 (HTTP/2)", RFC 7540,
	DOI 10.17487/RFC7540, May 2015, <https://www.rfc-		DOI 10.17487/RFC7540, May 2015,
	editor.org/info/rfc7540>.		<https://www.rfc-editor.org/info/rfc7540>.
	5.2. Informative References
	[RFC5988] Nottingham, M., "Web Linking", RFC 5988,		[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
	DOI 10.17487/RFC5988, October 2010, <https://www.rfc-		2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
	editor.org/info/rfc5988>.		May 2017, <https://www.rfc-editor.org/info/rfc8174>.
	[RFC6929] DeKok, A. and A. Lior, "Remote Authentication Dial In User		5.2. Informative References
	Service (RADIUS) Protocol Extensions", RFC 6929,
	DOI 10.17487/RFC6929, April 2013, <https://www.rfc-
	editor.org/info/rfc6929>.
	[RFC6960] Santesson, S., Myers, M., Ankney, R., Malpani, A.,		[RFC6960] Santesson, S., Myers, M., Ankney, R., Malpani, A.,
	Galperin, S., and C. Adams, "X.509 Internet Public Key		Galperin, S., and C. Adams, "X.509 Internet Public Key
	Infrastructure Online Certificate Status Protocol - OCSP",		Infrastructure Online Certificate Status Protocol - OCSP",
	RFC 6960, DOI 10.17487/RFC6960, June 2013,		RFC 6960, DOI 10.17487/RFC6960, June 2013,
	<https://www.rfc-editor.org/info/rfc6960>.		<https://www.rfc-editor.org/info/rfc6960>.
			[RFC6962] Laurie, B., Langley, A., and E. Kasper, "Certificate
			Transparency", RFC 6962, DOI 10.17487/RFC6962, June 2013,
			<https://www.rfc-editor.org/info/rfc6962>.
	[RFC7230] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer		[RFC7230] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
	Protocol (HTTP/1.1): Message Syntax and Routing",		Protocol (HTTP/1.1): Message Syntax and Routing",
	RFC 7230, DOI 10.17487/RFC7230, June 2014,		RFC 7230, DOI 10.17487/RFC7230, June 2014,
	<https://www.rfc-editor.org/info/rfc7230>.		<https://www.rfc-editor.org/info/rfc7230>.
	[RFC7838] Nottingham, M., McManus, P., and J. Reschke, "HTTP		[RFC7838] Nottingham, M., McManus, P., and J. Reschke, "HTTP
	Alternative Services", RFC 7838, DOI 10.17487/RFC7838,		Alternative Services", RFC 7838, DOI 10.17487/RFC7838,
	April 2016, <https://www.rfc-editor.org/info/rfc7838>.		April 2016, <https://www.rfc-editor.org/info/rfc7838>.
			[RFC8288] Nottingham, M., "Web Linking", RFC 8288,
			DOI 10.17487/RFC8288, October 2017,
			<https://www.rfc-editor.org/info/rfc8288>.
			5.3. URIs
			[1] https://lists.w3.org/Archives/Public/ietf-http-wg/
			[2] http://httpwg.github.io/
			[3] https://github.com/httpwg/http-extensions/labels/origin-frame
	Appendix A. Non-Normative Processing Algorithm		Appendix A. Non-Normative Processing Algorithm
	The following algorithm illustrates how a client could handle		The following algorithm illustrates how a client could handle
	received ORIGIN frames:		received ORIGIN frames:
	1. If the client is configured to use a proxy for the connection,		1. If the client is configured to use a proxy for the connection,
	ignore the frame and stop processing.		ignore the frame and stop processing.
	2. If the connection is not identified with the "h2" protocol		2. If the connection is not identified with the "h2" protocol
	identifier or another protocol that has explicitly opted into		identifier or another protocol that has explicitly opted into
	skipping to change at page 9, line 32 ¶		skipping to change at page 10, line 9 ¶
	obligated to use it, or to advertise all origins which they might be		obligated to use it, or to advertise all origins which they might be
	able to answer a request for.		able to answer a request for.
	For example, it can be used to inform the client that the connection		For example, it can be used to inform the client that the connection
	is to only be used for the SNI-based origin, by sending an empty		is to only be used for the SNI-based origin, by sending an empty
	ORIGIN frame. Or, a larger number of origins can be indicated by		ORIGIN frame. Or, a larger number of origins can be indicated by
	including a payload.		including a payload.
	Generally, this information is most useful to send before sending any		Generally, this information is most useful to send before sending any
	part of a response that might initiate a new connection; for example,		part of a response that might initiate a new connection; for example,
	"Link" headers [RFC5988] in a response HEADERS, or links in the		"Link" header fields [RFC8288] in a response HEADERS, or links in the
	response body.		response body.
	Therefore, the ORIGIN frame ought be sent as soon as possible on a		Therefore, the ORIGIN frame ought be sent as soon as possible on a
	connection, ideally before any HEADERS or PUSH_PROMISE frames.		connection, ideally before any HEADERS or PUSH_PROMISE frames.
	However, if it's desirable to associate a large number of origins		However, if it's desirable to associate a large number of origins
	with a connection, doing so might introduce end-user perceived		with a connection, doing so might introduce end-user perceived
	latency, due to their size. As a result, it might be necessary to		latency, due to their size. As a result, it might be necessary to
	select a "core" set of origins to send initially, expanding the set		select a "core" set of origins to send initially, expanding the set
	of origins the connection is used for with subsequent ORIGIN frames		of origins the connection is used for with subsequent ORIGIN frames
	later (e.g., when the connection is idle).		later (e.g., when the connection is idle).
	That said, senders are encouraged to include as many origins as		That said, senders are encouraged to include as many origins as
	practical within a single ORIGIN frame; clients need to make		practical within a single ORIGIN frame; clients need to make
	decisions about creating connections on the fly, and if the origin		decisions about creating connections on the fly, and if the origin
	set is split across many frames, their behaviour might be suboptimal.		set is split across many frames, their behaviour might be suboptimal.
	Senders take note that, as per [RFC6454] Section 4, the values in an		Senders take note that, as per Section 4, Step 5 of [RFC6454], the
	ORIGIN header need to be case-normalised before serialisation.		values in an ORIGIN header need to be case-normalised before
			serialisation.
	Finally, servers that host alternative services [RFC7838] will need		Finally, servers that host alternative services [RFC7838] will need
	to explicitly advertise their origins when sending ORIGIN, because		to explicitly advertise their origins when sending ORIGIN, because
	the default contents of the Origin Set (as per Section 2.3) do not		the default contents of the Origin Set (as per Section 2.3) do not
	contain any Alternative Services' origins, even if they have been		contain any Alternative Services' origins, even if they have been
	used previously on the connection.		used previously on the connection.
	Authors' Addresses		Authors' Addresses
	Mark Nottingham		Mark Nottingham
End of changes. 40 change blocks.
	93 lines changed or deleted		113 lines changed or added
This html diff was produced by rfcdiff 1.48. The latest version is available from http://tools.ietf.org/tools/rfcdiff/