draft-ietf-6man-uri-zoneid-02.txt		draft-ietf-6man-uri-zoneid-03.txt
	6MAN B. Carpenter		6MAN B. Carpenter
	Internet-Draft Univ. of Auckland		Internet-Draft Univ. of Auckland
	Updates: 3986, 4007 (if approved) R. Hinden		Updates: 3986 (if approved) R. Hinden
	Intended status: Standards Track Check Point		Intended status: Standards Track Check Point
	Expires: January 12, 2013 July 11, 2012		Expires: March 14, 2013 September 10, 2012
	Representing IPv6 Zone Identifiers in Address Literals and Uniform		Representing IPv6 Zone Identifiers in Address Literals and Uniform
	Resource Identifiers		Resource Identifiers
	draft-ietf-6man-uri-zoneid-02		draft-ietf-6man-uri-zoneid-03
	Abstract		Abstract
	This document describes how the Zone Identifier of an IPv6 scoped		This document describes how the Zone Identifier of an IPv6 scoped
	address can be represented in a a literal IPv6 address and in a		address can be represented in a literal IPv6 address and in a Uniform
	Uniform Resource Identifier that includes such a literal address. It		Resource Identifier that includes such a literal address. It updates
	updates RFC 3986 and RFC 4007 accordingly.		RFC 3986 accordingly.
	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 http://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 January 12, 2013.		This Internet-Draft will expire on March 14, 2013.
	Copyright Notice		Copyright Notice
	Copyright (c) 2012 IETF Trust and the persons identified as the		Copyright (c) 2012 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		(http://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
	skipping to change at page 2, line 11		skipping to change at page 2, line 11
	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 . . . . . . . . . . . . . . . . . . . . . . . . . 3		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
	2. Specification . . . . . . . . . . . . . . . . . . . . . . . . . 4		2. Specification . . . . . . . . . . . . . . . . . . . . . . . . . 4
	3. Web Browsers . . . . . . . . . . . . . . . . . . . . . . . . . 5		3. Web Browsers . . . . . . . . . . . . . . . . . . . . . . . . . 5
	4. Security Considerations . . . . . . . . . . . . . . . . . . . . 6		4. Security Considerations . . . . . . . . . . . . . . . . . . . . 5
	5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6		5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
	6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6		6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6
	7. Change log [RFC Editor: Please remove] . . . . . . . . . . . . 7		7. Change log [RFC Editor: Please remove] . . . . . . . . . . . . 6
	8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7		8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7
	8.1. Normative References . . . . . . . . . . . . . . . . . . . 7		8.1. Normative References . . . . . . . . . . . . . . . . . . . 7
	8.2. Informative References . . . . . . . . . . . . . . . . . . 8		8.2. Informative References . . . . . . . . . . . . . . . . . . 7
	Appendix A. Alternatives Considered . . . . . . . . . . . . . . . 8		Appendix A. Alternatives Considered . . . . . . . . . . . . . . . 8
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9
	1. Introduction		1. Introduction
	[RFC3986] defined how a literal IPv6 address can be represented in		[RFC3986] defined how a literal IPv6 address can be represented in
	the "host" part of a Uniform Resource Identifier (URI).		the "host" part of a Uniform Resource Identifier (URI).
	Subsequently, [RFC4007] extended the text representation of limited-		Subsequently, [RFC4007] extended the text representation of limited-
	scope IPv6 addresses such that a zone identifier may be concatenated		scope IPv6 addresses such that a zone identifier may be concatenated
	to a literal address, for purposes described in that RFC. Zone		to a literal address, for purposes described in that RFC. Zone
	skipping to change at page 3, line 37		skipping to change at page 3, line 37
	Some versions of some browsers accept the RFC 4007 syntax for scoped		Some versions of some browsers accept the RFC 4007 syntax for scoped
	IPv6 addresses embedded in URIs, i.e., they have been coded to		IPv6 addresses embedded in URIs, i.e., they have been coded to
	interpret the "%" sign according to RFC 4007 instead of RFC 3986.		interpret the "%" sign according to RFC 4007 instead of RFC 3986.
	Clearly this approach is very convenient for users, although it		Clearly this approach is very convenient for users, although it
	formally breaches the syntax rules of RFC 3986. The present document		formally breaches the syntax rules of RFC 3986. The present document
	defines an alternative approach that respects and extends the rules		defines an alternative approach that respects and extends the rules
	of URI syntax, and IPv6 literals in general, to be consistent.		of URI syntax, and IPv6 literals in general, to be consistent.
	Thus, this document updates [RFC3986] by adding syntax to allow a		Thus, this document updates [RFC3986] by adding syntax to allow a
	zone identifier to be included in a literal IPv6 address within a		zone identifier to be included in a literal IPv6 address within a
	URI. It also updates [RFC4007], in particular by adding a second		URI.
	allowed delimiter for zone identifiers.
	It should be noted that in other contexts than a user interface, a		It should be noted that in other contexts than a user interface, a
	zone identifier is mapped into a numeric zone index or interface		zone identifier is mapped into a numeric zone index or interface
	number. The MIB textual convention [RFC4001] and the socket		number. The MIB textual convention [RFC4001] and the socket
	interface [RFC3493] define this as a 32 bit unsigned integer. The		interface [RFC3493] define this as a 32 bit unsigned integer. The
	mapping between the human-readable zone identifier string and the		mapping between the human-readable zone identifier string and the
	numeric value is a host-specific function that varies between		numeric value is a host-specific function that varies between
	operating systems. The present document is concerned only with the		operating systems. The present document is concerned only with the
	human-readable string.		human-readable string.
	skipping to change at page 4, line 28		skipping to change at page 4, line 26
	happened to choose.		happened to choose.
	In a URI, a literal IPv6 address is always embedded between "[" and		In a URI, a literal IPv6 address is always embedded between "[" and
	"]". This document specifies how a <zone_id> can be appended to the		"]". This document specifies how a <zone_id> can be appended to the
	address. A <zone_id> SHOULD contain only ASCII characters classified		address. A <zone_id> SHOULD contain only ASCII characters classified
	in RFC 3986 as "unreserved", which conveniently excludes "]" in order		in RFC 3986 as "unreserved", which conveniently excludes "]" in order
	to simplify parsing.		to simplify parsing.
	Unfortunately "%" is always treated as an escape character in a URI,		Unfortunately "%" is always treated as an escape character in a URI,
	and according to RFC 3986 it MUST therefore itself be escaped in a		and according to RFC 3986 it MUST therefore itself be escaped in a
	URI, in the form "%25". For this reason, "-" (hyphen) is used		URI, in the form "%25". Thus, the scoped address fe80::a%en1 would
	instead as the separator when a <zone_id> is included in a URI.		appear in a URI as http://[fe80::a%25en1].
	Thus, the scoped address fe80::a%en1 would appear in a URI as
	http://[fe80::a-en1].
	If an operating system uses any other characters in zone or interface		If an operating system uses any other characters in zone or interface
	identifiers that are not in the "unreserved" character set, they MUST		identifiers that are not in the "unreserved" character set, they MUST
	be escaped with a "%" sign according to RFC 3986.		be escaped with a "%" sign according to RFC 3986.
	We now present the necessary formal syntax.		We now present the necessary formal syntax.
	In RFC 3986, the IPv6 literal format is formally defined in ABNF		In RFC 3986, the IPv6 literal format is formally defined in ABNF
	[RFC5234] by the following rule:		[RFC5234] by the following rule:
	skipping to change at page 5, line 9		skipping to change at page 4, line 50
	To provide support for a zone identifier, the existing syntax of		To provide support for a zone identifier, the existing syntax of
	IPv6address is retained, and a zone identifier may be added		IPv6address is retained, and a zone identifier may be added
	optionally to any literal address. This allows flexibility for		optionally to any literal address. This allows flexibility for
	unknown future uses. The rule quoted above from RFC 3986 is replaced		unknown future uses. The rule quoted above from RFC 3986 is replaced
	by three rules:		by three rules:
	IP-literal = "[" ( IPv6addrz / IPvFuture ) "]"		IP-literal = "[" ( IPv6addrz / IPvFuture ) "]"
	ZoneID = 1*( unreserved / pct-encoded )		ZoneID = 1*( unreserved / pct-encoded )
	IPv6addrz = IPv6address [ "-" ZoneID ]		IPv6addrz = IPv6address [ "%" ZoneID ]
	Section 11 of RFC 4007 is updated to allow "-" as well as "%" as the
	preceding delimiter of a ZoneID.
	The rules in [RFC5952] SHOULD be applied in producing URIs.		The rules in [RFC5952] SHOULD be applied in producing URIs.
	RFC 3986 states that URIs have a global scope, but that in some cases		RFC 3986 states that URIs have a global scope, but that in some cases
	their interpretation depends on the end-user's context. URIs		their interpretation depends on the end-user's context. URIs
	including a ZoneID are to be interpreted only in the context of the		including a ZoneID are to be interpreted only in the context of the
	host where they originate, since the ZoneID is of local signifance		host where they originate, since the ZoneID is of local signifance
	only.		only.
	The 6man WG discussed and rejected an alternative in which the		The 6man WG discussed and rejected an alternative in which the
	skipping to change at page 5, line 45		skipping to change at page 5, line 36
	Due to the lack of a standard in this area, web browsers have been		Due to the lack of a standard in this area, web browsers have been
	inconsistent in providing for ZoneIDs. Many have no support, but		inconsistent in providing for ZoneIDs. Many have no support, but
	there are examples of ad hoc support. For example, older versions of		there are examples of ad hoc support. For example, older versions of
	Firefox allowed the use of a ZoneID preceded by an unescaped "%"		Firefox allowed the use of a ZoneID preceded by an unescaped "%"
	character, but this was removed for consistency with RFC 3986. As		character, but this was removed for consistency with RFC 3986. As
	another example, recent versions of Internet Explorer allow use of a		another example, recent versions of Internet Explorer allow use of a
	ZoneID preceded by a "%" character escaped as "%25", still beyond the		ZoneID preceded by a "%" character escaped as "%25", still beyond the
	syntax allowed by RFC 3986. This syntax extension is in fact used		syntax allowed by RFC 3986. This syntax extension is in fact used
	internally in the Windows operating system and some of its APIs.		internally in the Windows operating system and some of its APIs.
	In recent years, web browsers have evolved considerably and now		This document implies that all browsers should recognise a ZoneID
	accept and parse many forms of input that are not a formal URI.		preceded by an escaped "%". In the spirit of "be liberal with what
	Examples of this include host names, search items, bookmarks, search		you accept", we also recommend that URI parsers accept bare "%" signs
	history, etc. For example the Google Chrome browser now calls the		(i.e., a "%" not followed by two valid hexadecimal characters). This
	"address bar" the "omnibox" [chrome]. The authors believe it is		makes it easy for a user to copy and paste a string such as
	feasible, and very convenient for users, if browsers also allow (in		"fe80::a%en1" from the output of a "ping" command and have it work.
	addition to the formal URI syntax defined in this document) a syntax
	that will enable cut and paste. For example:
	http://[fe80::a%en1]
	It seems that modern browsers can be adapted to parse this because it
	is inside of the "[" "]"'s. This would permit the output of commands
	like ping6 -w ff02::1%en1 to be "cut and pasted" into a browser
	address bar. Consequently this document recommends that browsers
	support this syntax in addition to the formal URI syntax defined
	above.
	4. Security Considerations		4. Security Considerations
	The security considerations of [RFC3986] and [RFC4007] apply. In		The security considerations of [RFC3986] and [RFC4007] apply. In
	particular, this URI format creates a specific pathway by which a		particular, this URI format creates a specific pathway by which a
	deceitful zone index might be communicated, as mentioned in the final		deceitful zone index might be communicated, as mentioned in the final
	security consideration of RFC 4007. It is emphasised that the format		security consideration of RFC 4007. It is emphasised that the format
	is intended only for debugging purposes, but of course this intention		is intended only for debugging purposes, but of course this intention
	does not prevent misuse.		does not prevent misuse.
	To limit this risk, implementations SHOULD NOT allow use of this		To limit this risk, implementations SHOULD NOT allow use of this
	format except for well-defined usages such as sending to link local		format except for well-defined usages such as sending to link local
	addresses under prefix fe80::/10.		addresses under prefix fe80::/10.
	An HTTP server or proxy MUST ignore any ZoneID attached to an		An HTTP server or proxy MUST ignore any ZoneID attached to an
	incoming URI, as it only has local significance at the sending host.		incoming URI, as it only has local significance at the sending host.
	The addition of a choice between "%" and "-" as the delimiter
	preceding a ZoneID slightly complicates the string comparison issue
	discussed in [I-D.iab-identifier-comparison].
	5. IANA Considerations		5. IANA Considerations
	This document requests no action by IANA.		This document requests no action by IANA.
	6. Acknowledgements		6. Acknowledgements
	The lack of this format was first pointed out by Margaret Wasserman		The lack of this format was first pointed out by Margaret Wasserman
	some years ago, and more recently by Kerry Lynn. A previous draft		some years ago, and more recently by Kerry Lynn. A previous draft
	document by Martin Duerst and Bill Fenner [I-D.fenner-literal-zone]		document by Martin Duerst and Bill Fenner [I-D.fenner-literal-zone]
	discussed this topic but was not finalised.		discussed this topic but was not finalised.
	Valuable comments and contributions were made by Karl Auer, Carsten		Valuable comments and contributions were made by Karl Auer, Carsten
	Bormann, Brian Haberman, Tatuya Jinmei, Tom Petch, Tomoyuki Sahara,		Bormann, Brian Haberman, Tatuya Jinmei, Tom Petch, Tomoyuki Sahara,
	Juergen Schoenwaelder, Dave Thaler, and Ole Troan.		Juergen Schoenwaelder, Dave Thaler, and Ole Troan.
			Stuart Cheshire suggested the current approach taken by this
			document.
	Brian Carpenter was a visitor at the Computer Laboratory, Cambridge		Brian Carpenter was a visitor at the Computer Laboratory, Cambridge
	University during part of this work.		University during part of this work.
	This document was produced using the xml2rfc tool [RFC2629].		This document was produced using the xml2rfc tool [RFC2629].
	7. Change log [RFC Editor: Please remove]		7. Change log [RFC Editor: Please remove]
			draft-ietf-6man-uri-zoneid-03: reverted to percent-encoded model
			following WGLC, 2012-09-10.
	draft-ietf-6man-uri-zoneid-02: additional WG comments, 2012-07-11.		draft-ietf-6man-uri-zoneid-02: additional WG comments, 2012-07-11.
	draft-ietf-6man-uri-zoneid-01: use "-" instead of %25, listed		draft-ietf-6man-uri-zoneid-01: use "-" instead of %25, listed
	alternatives in Appendix, according to WG debate, added suggestion		alternatives in Appendix, according to WG debate, added suggestion
	for browser developers, 2012-05-29.		for browser developers, 2012-05-29.
	draft-ietf-6man-uri-zoneid-00: adopted by WG, fixed syntax to allow		draft-ietf-6man-uri-zoneid-00: adopted by WG, fixed syntax to allow
	for % encoded characters, 2012-02-17.		for % encoded characters, 2012-02-17.
	draft-carpenter-6man-uri-zoneid-01: chose Option 2, removed 15		draft-carpenter-6man-uri-zoneid-01: chose Option 2, removed 15
	skipping to change at page 8, line 15		skipping to change at page 7, line 40
	8.2. Informative References		8.2. Informative References
	[I-D.fenner-literal-zone]		[I-D.fenner-literal-zone]
	Fenner, B. and M. Duerst, "Formats for IPv6 Scope Zone		Fenner, B. and M. Duerst, "Formats for IPv6 Scope Zone
	Identifiers in Literal Address Formats",		Identifiers in Literal Address Formats",
	draft-fenner-literal-zone-02 (work in progress),		draft-fenner-literal-zone-02 (work in progress),
	October 2005.		October 2005.
	[I-D.iab-identifier-comparison]		[I-D.iab-identifier-comparison]
	Thaler, D., "Issues in Identifier Comparison for Security		Thaler, D., "Issues in Identifier Comparison for Security
	Purposes", draft-iab-identifier-comparison-02 (work in		Purposes", draft-iab-identifier-comparison-03 (work in
	progress), May 2012.		progress), July 2012.
	[RFC2629] Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629,		[RFC2629] Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629,
	June 1999.		June 1999.
	[RFC3493] Gilligan, R., Thomson, S., Bound, J., McCann, J., and W.		[RFC3493] Gilligan, R., Thomson, S., Bound, J., McCann, J., and W.
	Stevens, "Basic Socket Interface Extensions for IPv6",		Stevens, "Basic Socket Interface Extensions for IPv6",
	RFC 3493, February 2003.		RFC 3493, February 2003.
	[RFC4001] Daniele, M., Haberman, B., Routhier, S., and J.		[RFC4001] Daniele, M., Haberman, B., Routhier, S., and J.
	Schoenwaelder, "Textual Conventions for Internet Network		Schoenwaelder, "Textual Conventions for Internet Network
	Addresses", RFC 4001, February 2005.		Addresses", RFC 4001, February 2005.
	[chrome] Google, "Use the address bar (omnibox)", 2012, <http://		[chrome] Google, "Use the address bar (omnibox)", 2012, <http://
	support.google.com/chrome/bin/answer.py?answer=95440>.		support.google.com/chrome/bin/answer.py?answer=95440>.
	Appendix A. Alternatives Considered		Appendix A. Alternatives Considered
	1. Leave the problem unsolved.		1. Leave the problem unsolved.
	skipping to change at page 9, line 10		skipping to change at page 8, line 37
	Advantage: allows use of browser, allows cut and paste.		Advantage: allows use of browser, allows cut and paste.
	Disadvantage: invalid syntax under RFC 3986; not acceptable to		Disadvantage: invalid syntax under RFC 3986; not acceptable to
	URI community.		URI community.
	3. Escaping the escape character as allowed by RFC 3986:		3. Escaping the escape character as allowed by RFC 3986:
	http://[fe80::a%25en1]		http://[fe80::a%25en1]
	Advantage: allows use of browser.		Advantage: allows use of browser, consistent with general URI
			syntax.
	Disadvantage: ugly and confusing, doesn't allow simple cut and		Disadvantage: somewhat ugly and confusing, doesn't allow simple
	paste.		cut and paste.
	4. Alternative separator		4. Alternative separator
	http://[fe80::a-en1]		http://[fe80::a-en1]
	Advantage: allows use of browser, simple syntax		Advantage: allows use of browser, simple syntax
	Disadvantage: Requires all IPv6 address literal parsers and		Disadvantage: Requires all IPv6 address literal parsers and
	generators to be updated in order to allow simple cut and paste.		generators to be updated in order to allow simple cut and paste;
			inconsistent with existing tools and practice.
	Note: the initial proposal for this choice was to use an		Note: the initial proposal for this choice was to use an
	underscore as the separator, but it was noted that this becomes		underscore as the separator, but it was noted that this becomes
	effectively invisible when a user interface automatically		effectively invisible when a user interface automatically
	underlines URLs.		underlines URLs.
	5. With the "IPvFuture" syntax left open in RFC 3986:		5. With the "IPvFuture" syntax left open in RFC 3986:
	http://[v6.fe80::a_en1]		http://[v6.fe80::a_en1]
End of changes. 20 change blocks.
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