6MAN B. Carpenter Internet-Draft Univ. of Auckland Updates: 3986, 4007 (if approved) R. Hinden Intended status: Standards Track Check Point Expires: June 9, 2012 December 7, 2011 Representing IPv6 Zone Identifiers in Uniform Resource Identifiers draft-carpenter-6man-uri-zoneid-00 Abstract This document describes how the Zone Identifier of an IPv6 scoped address can be represented in a Uniform Resource Identifier that includes a literal IPv6 address. It updates RFC 3986 and RFC 4007. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on June 9, 2012. Copyright Notice Copyright (c) 2011 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Carpenter & Hinden Expires June 9, 2012 [Page 1]
Internet-Draft IPv6 Zone ID in URI December 2011 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Specification . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5 6. Change log [RFC Editor: Please remove] . . . . . . . . . . . . 5 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5 7.1. Normative References . . . . . . . . . . . . . . . . . . . 5 7.2. Informative References . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6 Carpenter & Hinden Expires June 9, 2012 [Page 2]
Internet-Draft IPv6 Zone ID in URI December 2011 1. Introduction [RFC3986] defined how a literal IPv6 address can be represented in the "host" part of a Uniform Resource Identifier (URI). Subsequently, [RFC4007] extended the text representation of limited- scope IPv6 addresses such that a zone identifier may be concatenated to an address, for purposes described in that RFC. Zone identifiers are especially useful in contexts where literal addresses are typically used, for example during fault diagnosis, when it may be essential to specify which interface is used for sending to a link local address. It should be noted that zone identifiers have purely local meaning within the host where they are defined, and they are completely meaningless for any other host. RFC 4007 does not specify how zone identifiers are to be represented in URIs. Practical experience has shown that this feature is useful, in particular when using a web browser for debugging with link local addresses, but as it is undefined, it is not implemented consistently in URI parsers or in browsers. This document updates [RFC3986] by adding syntax to allow a zone identifier to be included in a literal IPv6 address. It also clarifies some statements in [RFC4007]. The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. 2. Specification According to RFC 4007, a zone identifier is attached to the textual representation of an IPv6 address by concatenating "%" followed by <zone_id>, where <zone_id> is a string identifying the zone of the address. However, RFC 4007 gives no precise definition of the character set allowed in <zone_id>. There are no rules or de facto standards for this. For example, the first Ethernet interface in a host might be called %0, %1, %en1, %eth0, or whatever the implementer happened to choose. In a URI, a literal IPv6 address is always embedded between "[" and "]". This document specifies that <zone_id> may contain any ASCII character classified in RFC 3986 as "unreserved", which conveniently excludes "]" in order to simplify parsing. There is an additional complication in that "%" is always treated as an escape character in a URI, and according to RFC 3986 it must therefore itself be escaped in a URI, in the form "%25". Thus, the Carpenter & Hinden Expires June 9, 2012 [Page 3]
Internet-Draft IPv6 Zone ID in URI December 2011 scoped address fe80::a%en1 would appear in a produced URI as http://[fe80::a%25en1]. In RFC 3986, the IPv6 literal format is formally defined in ABNF [RFC5234] by the following rule: IP-literal = "[" ( IPv6address / IPvFuture ) "]" To provide support for a zone identifier, firstly a new rule is added: ZoneID = 1*15unreserved Then two options are possible (to be discussed). OPTION 1: The existing syntax of IPv6address is extended by adding a specific option for the case of link-local addresses. The following definition of IPv6address replaces that given in RFC 3986: IPv6address = 6( h16 ":" ) ls32 / "::" 5( h16 ":" ) ls32 / [ h16 ] "::" 4( h16 ":" ) ls32 / [ *1( h16 ":" ) h16 ] "::" 3( h16 ":" ) ls32 / [ *2( h16 ":" ) h16 ] "::" 2( h16 ":" ) ls32 / [ *3( h16 ":" ) h16 ] "::" h16 ":" ls32 / [ *4( h16 ":" ) h16 ] "::" ls32 / [ *5( h16 ":" ) h16 ] "::" h16 / [ *6( h16 ":" ) h16 ] "::" / "fe80::" [ *3( h16 ":" ) h16 ] "%" ZoneID OPTION 2: The existing syntax of IPv6address is retained, and a zone identifier may be added optionally to any literal address. This allows flexibility for unknown future uses. The rule quoted above from RFC 3986 is replaced by two rules: IP-literal = "[" ( IPv6addrz / IPvFuture ) "]" IPv6addrz = IPv6address [ "%" ZoneID ] The rules in [RFC5952] SHOULD be applied in producing URIs, and the user MUST replace "%" by "%25" when manually constructing such a URI. Carpenter & Hinden Expires June 9, 2012 [Page 4]
Internet-Draft IPv6 Zone ID in URI December 2011 3. Security Considerations The security considerations of [RFC3986] and [RFC4007] apply. In particular, this URI format creates a specific pathway by which a deceitful zone index might be communicated, as mentioned in the final security consideration of RFC 4007. It is emphasised that the format is intended only for debugging purposes, but of course this intention does not prevent misuse. IF OPTION 2 IS CHOSEN: To limit this risk, implementations SHOULD NOT allow use of the format except for link local addresses under prefix fe80::/10. 4. IANA Considerations This document requests no action by IANA. 5. Acknowledgements The lack of this format was pointed out by Kerry Lynn. Valuable comments and contributions were made by... This document was produced using the xml2rfc tool [RFC2629]. 6. Change log [RFC Editor: Please remove] draft-carpenter-v6ops-label-balance-00: original version, 2011-12-07. 7. References 7.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986, January 2005. [RFC4007] Deering, S., Haberman, B., Jinmei, T., Nordmark, E., and B. Zill, "IPv6 Scoped Address Architecture", RFC 4007, March 2005. Carpenter & Hinden Expires June 9, 2012 [Page 5]
Internet-Draft IPv6 Zone ID in URI December 2011 [RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", STD 68, RFC 5234, January 2008. [RFC5952] Kawamura, S. and M. Kawashima, "A Recommendation for IPv6 Address Text Representation", RFC 5952, August 2010. 7.2. Informative References [RFC2629] Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629, June 1999. Authors' Addresses Brian Carpenter Department of Computer Science University of Auckland PB 92019 Auckland, 1142 New Zealand Email: brian.e.carpenter@gmail.com Robert M. Hinden Check Point Software Technologies, Inc. 800 Bridge Parkway Redwood City, CA 94065 US Email: bob.hinden@gmail.com Carpenter & Hinden Expires June 9, 2012 [Page 6]