Internet Draft R. Atkinson draft-rja-ilnp-icmp-03.txt Consultant Category: Experimental 24 June 2010 Expires: 24 DEC 2010 ICMP Locator Update message draft-rja-ilnp-icmp-03.txt Status of this Memo Distribution of this memo is unlimited. Copyright (c) 2010 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. This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. This document may contain material from IETF Documents or IETF Contributions published or made publicly available before November 10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to allow modifications of such material outside the IETF Standards Process. Without obtaining an adequate license from the person(s) controlling the copyright in such materials, this document may not be modified outside the IETF Standards Process, and derivative works of it may not be created outside the IETF Standards Process, except to format it for publication as an RFC or to translate it into languages other than English. This document may not be modified, and derivative works of it may not be created, except to publish it as an RFC or to translate it into languages other than English. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Atkinson Expires in 6 months [Page 1]
Internet Draft ILNP ICMP 24 JUN 2010 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/1id-abstracts.html The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html This document is not on the IETF standards-track and does not specify any level of standard. This document merely provides information for the Internet community. This document has had extensive review within the IRTF Routing Research Group, and is part of the ILNP document set. Also, ILNP is one of the recommendations made by the RG Chairs. Separately, various refereed research papers on ILNP have also been published during this decade. So the ideas contained herein also have had broader review than just the IRTF Routing RG. Abstract This note specifies an experimental ICMPv6 message type used with the Identifier-Locator Network Protocol (ILNP). This message is used to dynamically update Identifier/Locator bindings for an existing ILNP session. This is a product of the IRTF Routing RG. Table of Contents 1. Introduction ...........................................2 2. Syntax..................................................3 3. Transport Protocol Effects..............................5 4. Implementation Considerations...........................5 5. Backwards Compatibility.................................6 6. Security Considerations ................................6 7. IANA Considerations ....................................7 8. References .............................................7 1. Introduction At present, the research and development community are examining various alternatives for evolving the Internet Architecture. Several different classes of evolution are being considered. One class is Atkinson Expires in 6 months [Page 2]
Internet Draft ILNP ICMP 24 JUN 2010 often called "Map and Encapsulate", where traffic would be mapped and then tunnelled through the inter-domain core of the Internet. Another class being considered is sometimes known as "Identifier/Locator Split". This document relates to a proposal that is in the latter class of evolutionary approaches. In particular, the Identifier-Locator Network Protocol being described in this document and related Internet-Drafts is an evolution of IPv6. [ILNP- Intro] [ILNP-Nonce] [ILNP-DNS] [RFC 2460] The new ICMPv6 Locator Update message described in this document enables an ILNP-capable node to update its correspondents about the currently valid set of Locators valid to use in reaching the node sending this message. This new ICMPv6 message MUST NOT be used for IP sessions operating in classic IPv6 mode. This ICMPv6 message MUST ONLY be used for IP sessions that are operating in Identifier/Locator Split mode. Authentication is always required, as described in the Security Considerations section later in this note. Some might consider any and all use of ICMP to be undesirable. In that context, please note that while this specification uses ICMP, there is no architectural difference between using ICMP and using some different framing, for example UDP. 1.1 Terminology 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 RFC 2119. [RFC 2119] 2. Syntax Example ICMP message body for case where only 1 Locator value is being indicated: ------------------------------------------------------------ | ICMP Type | ICMP Code | Checksum | +-------------+---------------+-------------+--------------+ | Num of Locs | RESERVED | Preference | +-------------+---------------+-------------+--------------+ / Locator / +-------------+---------------+-------------+--------------+ Example ICMP message body for case where 2 Locator values are being indicated: Atkinson Expires in 6 months [Page 3]
Internet Draft ILNP ICMP 24 JUN 2010 ------------------------------------------------------------ | ICMP Type | ICMP Code | Checksum | +-------------+---------------+-------------+--------------+ | Num of Locs | RESERVED | Preference | +-------------+---------------+-------------+--------------+ / Locator / +-------------+---------------+-------------+--------------+ | RESERVED | Preference | +-------------+---------------+-------------+--------------+ / Locator / +-------------+---------------+-------------+--------------+ For cases where more than 2 Locator values are being indicated, the "RESERVED", "Preference", and "Locator" fields are appended as appropriate to carry the intended number of Locator fields. ICMP Type: This 8-bit field is set to the value XXX to indicate that this is a Locator Update message. ICMP Code: This 8-bit field indicates which kind of ICMP Locator Update this is. At present, the only valid value is 0, which means that this message contains all currently valid Locator values for the sending node. Checksum: This contains the ICMPv6 Checksum value for this packet. Num of Locs: This field contains the number of 64-bit Locators that follow the RESERVED field. This field must not contain the number zero, as each ILNP node needs to be reachable via at least 1 Locator value. Multi-homed nodes will have at least 2 Locator values. Reserved: These fields MUST be sent as zero. At this time, recipients should ignore the contents of these field, as these bits are reserved for future use. (Implementators should understand that these fields might be used in future.) Locator: This 64-bit field contains a valid Locator that can be used to reach the sending node. A variable number of Locator fields are concatenated one after another. These are Atkinson Expires in 6 months [Page 4]
Internet Draft ILNP ICMP 24 JUN 2010 listed in priority order, with the first Locator field containing the most preferred Locator value. Preference: A 16-bit unsigned integer which specifies the preference given to this Locator among other Locators in the same ICMP message. Lower Preference values are preferred over higher Preference values. NOTE: In order to prevent session stealing by an off-path adversary, all ICMP Locator Update packets MUST also contain an ILNP Nonce Destination Option with valid authentication information for the session associated with the ICMP Locator Update packet. The ILNP Nonce Destination Option is required in all cases, even if some other authentication mechanism (e.g. IP Authentication Header) is also in use. 3. Transport Protocol Effects This message has no impact on any transport protocol. The message may affect where packets for a given transport session are sent, but one of the design objectives for the I/L Split Mode (i.e. ILNP) is to decouple transport-protocols from network-layer changes. 4. Implementation Considerations Implementers may use any internal implementation they wish, provided that the external appearance is the same as this implementation approach. To support the Identifier/Locator Split operating mode, and retain the incremental deployability and backwards compatibility needed, the network layer needs a mode bit in the Transport Control Block (or its equivalent) to track which IP sessions are using the classic IPv6 mode and which IP sessions are using the Identifier/Locator Split mode. Further, when in the Identifier/Locator Split mode, nodes will need to retain a Correspondent Cache in the network layer that contains for each correspondent node: - Source Identifier(s) in use - Source Locator(s) in use - Destination Identifier(s) in use Atkinson Expires in 6 months [Page 5]
Internet Draft ILNP ICMP 24 JUN 2010 - Destination Locator(s) in use - Session Nonce value from Local Node to Correspondent Node - Session Nonce value from Correspondent Node to Local Node Please also read the discussion of this Correspondent Cache in the companion document [ILNP-Intro]. Implementions need to support a large number of Locator values being sent or received in a single ICMP Locator Update message, because a multi-homed node or multi-homed site might have a large number of upstream links to different service providers, each with its own Locator value. 5. Backwards Compatibility For all sessions operating in Identifier/Locator Split mode, inside each node the high-order 64-bits ("Locator") are always set to zero before the packet is sent upwards to the transport protocol. So any changes in Locator values used on the wire will be invisible to the transport protocol. In this mode, transport-layer checksums (e.g. TCP pseudo-header checksum) will be calculated with both Source Locator and Destination Locator fields set to all zero. For receipient nodes or sessions operating in the classic IPv6 mode or otherwise not in the Identifier/Locator Split mode, the ICMP Locator Update packet MUST be discarded by the recipient without being processed. 6. Security Considerations The ICMP Locator Update message MUST ONLY be used for IP sessions operating in the Identifier/Locator Split mode. The experimental Nonce Destination Option [ILNP-Nonce] MUST be present in packets containing an ICMPv6 Locator Update message. Further, the received Nonce Destination Option must contain the correct nonce value for the packet to be accepted by the recipient and then passed to the ICMPv6 protocol for processing. If either of these requirements are not met, the received packet MUST be discarded as not authentic, and a security event SHOULD be logged by the system receiving the non-authentic packet. For sessions operating in higher risk environments, the use of Atkinson Expires in 6 months [Page 6]
Internet Draft ILNP ICMP 24 JUN 2010 the IP Authentication Header *in addition* to the experimental Nonce Destination Option is recommended. Use of the IP Authentication Header to protect a packet does NOT permit the packet to be sent without the Nonce Destination Option. A broader discussion of ILNP Security Considerations is in [ILNP-Intro], and is incorporated here by reference. Implementions need to support the case where an ICMP Locator Update message contains a large number of Locator and Preference values and ought not develop a security fault (e.g. stack overflow) due to a received message containing more Locator values than expected. 7. IANA Considerations IANA is requested to assign a value, replacing the XXX, to the ICMP Type listed in Section 2, following the procedures in [RFC 4443]. There are no other IANA actions for this document. 8. References 8.1. Normative References [RFC 2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC 2460] S. Deering & R. Hinden, "Internet Protocol Version 6 Specification", RFC-2460, December 1998. [RFC 4443] A. Conta, S. Deering, and M. Gupta (Ed.), "Internet Control Message Protocol (ICMPv6) for the Internet Protocol Protocol Version 6 (IPv6) Specification", RFC 4443, March 2006. 8.2. Informative References [ILNP-Intro] Atkinson, R, "ILNP Concept of Operations", draft-rja-ilnp-intro-04.txt, June 2010. [ILNP-DNS] Atkinson, R, "DNS Resource Records for ILNP", draft-rja-ilnp-dns-04.txt, June 2010. [ILNP-Nonce] Atkinson, R, "Nonce Destination Option", Atkinson Expires in 6 months [Page 7]
Internet Draft ILNP ICMP 24 JUN 2010 draft-rja-ilnp-nonce-03.txt, June 2010. 7. ACKNOWLEDGEMENTS Steve Blake, Mohamed Boucadair, Saleem Bhatti, Steve Hailes, Joel Halpern, Mark Handley, Tony Li, and Yakov Rehkter (in alphabetical order) provided review and feedback on earlier versions of this document. AUTHOR'S ADDRESS R. Atkinson Consultant McLean, VA 22102 USA Email: rja.lists@gmail.com Expires: 24 DEC 2010 Atkinson Expires in 6 months [Page 8]