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rfc:rfc6746

Internet Research Task Force (IRTF) RJ Atkinson Request for Comments: 6746 Consultant Category: Experimental SN Bhatti ISSN: 2070-1721 U. St Andrews

                                                         November 2012
                        IPv4 Options for the
             Identifier-Locator Network Protocol (ILNP)

Abstract

 This document defines two new IPv4 Options that are used only with
 the Identifier-Locator Network Protocol for IPv4 (ILNPv4).  ILNP is
 an experimental, evolutionary enhancement to IP.  This document is a
 product of the IRTF Routing Research Group.

Status of This Memo

 This document is not an Internet Standards Track specification; it is
 published for examination, experimental implementation, and
 evaluation.
 This document defines an Experimental Protocol for the Internet
 community.  This document is a product of the Internet Research Task
 Force (IRTF).  The IRTF publishes the results of Internet-related
 research and development activities.  These results might not be
 suitable for deployment.  This RFC represents the individual
 opinion(s) of one or more members of the Routing Research Group of
 the Internet Research Task Force (IRTF).  Documents approved for
 publication by the IRSG are not a candidate for any level of Internet
 Standard; see Section 2 of RFC 5741.
 Information about the current status of this document, any errata,
 and how to provide feedback on it may be obtained at
 http://www.rfc-editor.org/info/rfc6746.

Atkinson & Bhatti Experimental [Page 1] RFC 6746 ILNPv4 Opts November 2012

Copyright Notice

 Copyright (c) 2012 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.
 This document may not be modified, and derivative works of it may not
 be created, except to format it for publication as an RFC or to
 translate it into languages other than English.

Table of Contents

 1. Introduction ....................................................2
    1.1. Document Roadmap ...........................................3
    1.2. Terminology ................................................4
 2. IPv4 Options for ILNPv4 .........................................4
    2.1. ILNPv4 Packet Format .......................................5
    2.2. ILNP Identifier Option for IPv4 ............................7
    2.3. ILNP Nonce Option for IPv4 .................................8
 3. Security Considerations .........................................8
 4. IANA Considerations .............................................9
 5. References ......................................................9
    5.1. Normative References .......................................9
    5.2. Informative References ....................................10
 6. Acknowledgements ...............................................11

1. Introduction

 This document is part of the ILNP document set, and it has had
 extensive review within the IRTF Routing RG.  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 have had much broader review than the
 IRTF Routing RG.  The views in this document were considered
 controversial by the Routing RG, but the RG reached a consensus that
 the document still should be published.  The Routing RG has had
 remarkably little consensus on anything, so virtually all Routing RG
 outputs are considered controversial.
 At present, the Internet research and development community is
 exploring various approaches to evolving the Internet Architecture to
 solve a variety of issues including, but not limited to, scalability

Atkinson & Bhatti Experimental [Page 2] RFC 6746 ILNPv4 Opts November 2012

 of inter-domain routing [RFC4984].  A wide range of other issues
 (e.g., site multihoming, node multihoming, site/subnet mobility, node
 mobility) are also active concerns at present.  Several different
 classes of evolution are being considered by the Internet research
 and development community.  One class is 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.
 The Identifier-Locator Network Protocol (ILNP) is a proposal for
 evolving the Internet Architecture.  It differs from the current
 Internet Architecture primarily by deprecating the concept of an IP
 Address and instead defining two new objects, each having crisp
 syntax and semantics.  The first new object is the Locator, a
 topology-dependent name for a subnetwork.  The other new object is
 the Identifier, which provides a topology-independent name for a
 node.

1.1. Document Roadmap

 This document describes a new IPv4 Nonce Option used by ILNPv4 nodes
 to carry a security nonce to prevent off-path attacks against ILNP
 ICMP messages and defines a new IPv4 Identifier Option used by ILNPv4
 nodes.
 The ILNP architecture can have more than one engineering
 instantiation.  For example, one can imagine a "clean-slate"
 engineering design based on the ILNP architecture.  In separate
 documents, we describe two specific engineering instances of ILNP.
 The term "ILNPv6" refers precisely to an instance of ILNP that is
 based upon, and backwards compatible with, IPv6.  The term "ILNPv4"
 refers precisely to an instance of ILNP that is based upon, and
 backwards compatible with, IPv4.
 Many engineering aspects common to both ILNPv4 and ILNPv6 are
 described in [RFC6741].  A full engineering specification for either
 ILNPv6 or ILNPv4 is beyond the scope of this document.
 Readers are referred to other related ILNP documents for details not
 described here:
 a) [RFC6740] is the main architectural description of ILNP, including
    the concept of operations.
 b) [RFC6741] describes engineering and implementation considerations
    that are common to both ILNPv4 and ILNPv6.

Atkinson & Bhatti Experimental [Page 3] RFC 6746 ILNPv4 Opts November 2012

 c) [RFC6742] defines additional DNS resource records that support
    ILNP.
 d) [RFC6743] defines a new ICMPv6 Locator Update message used by an
    ILNP node to inform its correspondent nodes of any changes to its
    set of valid Locators.
 e) [RFC6744] defines a new IPv6 Nonce Destination Option used by
    ILNPv6 nodes (1) to indicate to ILNP correspondent nodes (by
    inclusion within the initial packets of an ILNP session) that the
    node is operating in the ILNP mode and (2) to prevent off-path
    attacks against ILNP ICMP messages.  This Nonce is used, for
    example, with all ILNP ICMPv6 Locator Update messages that are
    exchanged among ILNP correspondent nodes.
 f) [RFC6745] defines a new ICMPv4 Locator Update message used by an
    ILNP node to inform its correspondent nodes of any changes to its
    set of valid Locators.
 g) [RFC6747] describes extensions to Address Resolution Protocol
    (ARP) for use with ILNPv4.
 h) [RFC6748] describes optional engineering and deployment functions
    for ILNP.  These are not required for the operation or use of ILNP
    and are provided as additional options.

1.2. 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 [RFC2119].

2. IPv4 Options for ILNPv4

 ILNP for IPv4 (ILNPv4) is merely a different instantiation of the
 ILNP architecture, so it retains the crisp distinction between the
 Locator and the Identifier.  As with ILNP for IPv6 (ILNPv6), when
 ILNPv4 is used for a network-layer session, the upper-layer protocols
 (e.g., TCP/UDP pseudo-header checksum, IPsec Security Association)
 bind only to the Identifiers, never to the Locators.  As with ILNPv6,
 only the Locator values are used for routing and forwarding ILNPv4
 packets.
 However, just as the packet format for IPv4 is different from IPv6,
 so the engineering details for ILNPv4 are different also.  Just as
 ILNPv6 is carefully engineered to be backwards-compatible with IPv6,
 ILNPv4 is carefully engineered to be backwards-compatible with IPv4.

Atkinson & Bhatti Experimental [Page 4] RFC 6746 ILNPv4 Opts November 2012

 Each of these options MUST be copied upon fragmentation.  Each of
 these options is used for control, so uses Option Class 0.
 Originally, these two options were specified to use separate IP
 option numbers.  However, only one IP Option (decimal 158) has been
 defined for experimental use with properties of MUST COPY and CONTROL
 [RFC4727].  So these two options have been reworked to share that
 same IP Option number (158).  To distinguish between the two actual
 options, the unsigned 8-bit field ILNPv4_OPT inside this option is
 examined.
 It is important for implementers to understand that IP Option 158 is
 not uniquely allocated to ILNPv4.  Other IPv4-related experiments
 might be using that IP Option value for different IP options having
 different IP Option formats.

2.1. ILNPv4 Packet Format

 The Source IP Address in the IPv4 header becomes the Source ILNPv4
 Locator value, while the Destination IP Address of the IPv4 header
 becomes the Destination ILNPv4 Locator value.  Of course, backwards
 compatibility requirements mean that ILNPv4 Locators use the same
 number space as IPv4 routing prefixes.
 ILNPv4 uses the same 64-bit Identifier, with the same modified EUI-64
 syntax, as ILNPv6.  Because the IPv4 address fields are much smaller
 than the IPv6 address fields, ILNPv4 cannot carry the Identifier
 values in the fixed portion of the IPv4 header.  The obvious two ways
 to carry the ILNP Identifier with ILNPv4 are either as an IPv4 Option
 or as an IPv6-style Extension Header placed after the IPv4 header and
 before the upper-layer protocol (e.g., OSPF, TCP, UDP, SCTP).
 Currently deployed IPv4 routers from multiple router vendors use
 packet forwarding silicon that is able to parse past IPv4 Options to
 examine the upper-layer protocol header at wire-speed on reasonably
 fast (e.g., 1 Gbps or better) network interfaces.  By contrast, no
 existing IPv4-capable packet forwarding silicon is able to parse past
 a new Extension Header for IPv4.  Hence, for engineering reasons,
 ILNPv4 uses a new IPv4 Option to carry the Identifier values.
 Another new IPv4 Option also carries a nonce value, performing the
 same function for ILNPv4 as the IPv6 Nonce Destination Option
 [RFC6744] performs for ILNPv6.

Atkinson & Bhatti Experimental [Page 5] RFC 6746 ILNPv4 Opts November 2012

   0                   1                   2                   3
   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |Version|  IHL  |Type of Service|          Total Length         |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |         Identification        |Flags|      Fragment Offset    |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |  Time to Live |    Protocol   |         Header Checksum       |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |                 Source Locator (32 bits)                      |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |              Destination Locator (32 bits)                    |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |      OT=158   |     OL=5      |      0x00     |ILNPv4_OPT=0x01|
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |                                                               |
  +                      Source Identifier                        +
  |                                                               |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |                                                               |
  +                    Destination Identifier                     +
  |                                                               |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |     OT=158    |     OL=2      |      0x00     |ILNPv4_OPT=0x02|
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |                      top 32 bits of nonce                     |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |                     lower 32 bits of nonce                    |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 Figure 1: ILNPv4 Header with ILNP ID Option and ILNP Nonce Option
         Notation for Figure 1:
                 IHL:  Internet Header Length
                  OT:  Option Type
                  OL:  Option Length

Atkinson & Bhatti Experimental [Page 6] RFC 6746 ILNPv4 Opts November 2012

2.2. ILNP Identifier Option for IPv4

  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |     OT=158    |     OL=20     |      0x00     |ILNPv4_OPT=0x01|
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                      Source Identifier                        |
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                    Destination Identifier                     |
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 Figure 2: ILNP Identifier Option for IPv4
        Notation for Figure 2:
                 OT:   Option Type
                 OL:   Option Length
 RFC 791, Page 15 specifies that the Option Length is measured in
 words and includes the Option Type octet, the Option Length octet,
 and the option data octets.
 The Source Identifier and Destination Identifier are unsigned 64-bit
 integers.  [RFC6741] specifies the syntax, semantics, and generation
 of ILNP Identifier values.  Using the same syntax and semantics for
 all instantiations of ILNP Identifiers simplifies specification and
 implementation, while also facilitating translation or transition
 between ILNPv4 and ILNPv6 should that be desirable in future.
 This IP Option MUST NOT be present in an IPv4 packet unless the
 packet is part of an ILNPv4 session.  ILNPv4 sessions MUST include
 this option in the first few packets of each ILNPv4 session and MAY
 include this option in all packets of the ILNPv4 session.  It is
 RECOMMENDED to include this option in all packets of the ILNPv4
 session if packet loss is higher than normal.

Atkinson & Bhatti Experimental [Page 7] RFC 6746 ILNPv4 Opts November 2012

2.3. ILNP Nonce Option for IPv4

  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |     OT=158    |     OL=2      |      0x00     |ILNPv4_OPT=0x02|
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                      top 32 bits of nonce                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                     lower 32 bits of nonce                    |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 Figure 3: ILNP Nonce Option for IPv4
        Notation for Figure 3:
                 OT:   Option Type
                 OL:   Option Length
 This option contains a 64-bit ILNP Nonce.  As noted in [RFC6740] and
 [RFC6741], all ILNP Nonce values are unidirectional.  This means, for
 example, that when TCP is in use, the underlying ILNPv4 session will
 have two different NONCE values: one from Initiator to Responder and
 another from Responder to Initiator.  The ILNP Nonce is used to
 provide non-cryptographic protection against off-path attacks (e.g.,
 forged ICMP messages from the remote end of a TCP session).
 Each NONCE value MUST be unpredictable (i.e., cryptographically
 random).  Guidance to implementers on generating cryptographically
 random values is provided in [RFC4086].
 This IP Option MUST NOT be present in an IPv4 packet unless the
 packet is part of an ILNPv4 session.  ILNPv4 nodes MUST include this
 option in the first few packets of each ILNP session, MUST include
 this option in all ICMP messages generated by endpoints participating
 in an ILNP session, and MAY include this option in all packets of an
 ILNPv4 session.

3. Security Considerations

 Security considerations for the overall ILNP Architecture are
 described in [RFC6740].  Additional common security considerations
 are described in [RFC6741].  This section describes security
 considerations specific to ILNPv4 topics discussed in this document.
 If the ILNP Nonce value is predictable, then an off-path attacker
 might be able to forge data or control packets.  This risk also is
 mitigated by the existing common practice of IP Source Address
 filtering [RFC2827] [RFC3704].

Atkinson & Bhatti Experimental [Page 8] RFC 6746 ILNPv4 Opts November 2012

 IP Security for ILNP [RFC6741] [RFC4301] provides cryptographic
 protection for ILNP data and control packets.  The ILNP Nonce Option
 is required in the circumstances described in Section 3, even if
 IPsec is also in use.  Deployments of ILNPv4 in high-threat
 environments SHOULD use IPsec for additional risk reduction.
 This option is intended to be used primarily end-to-end between a
 source node and a destination node.  However, unlike IPv6, IPv4 does
 not specify a method to distinguish between options with hop-by-hop
 behaviour versus end-to-end behaviour.
 [FILTERING] provides general discussion of potential operational
 issues with IPv4 options, along with specific advice for handling
 several specific IPv4 options.  Further, many deployed modern IP
 routers (both IPv4 and IPv6) have been explicitly configured to
 ignore all IP options, even including the "Router Alert" option, when
 forwarding packets not addressed to the router itself.  Reports
 indicate this has been done to preclude use of IP options as a
 (Distributed) Denial-of-Service (D)DoS attack vector on backbone
 routers.

4. IANA Considerations

 This document makes no request of IANA.
 If in the future the IETF decided to standardise ILNPv4, then
 allocation of two unique Header Option values to ILNPv4, one for the
 Identifier option and one for the Nonce option, would be sensible.

5. References

5.1. Normative References

 [RFC2119]   Bradner, S., "Key words for use in RFCs to Indicate
             Requirement Levels", BCP 14, RFC 2119, March 1997.
 [RFC4301]   Kent, S. and K. Seo, "Security Architecture for the
             Internet Protocol", RFC 4301, December 2005.
 [RFC4727]   Fenner, B., "Experimental Values In IPv4, IPv6, ICMPv4,
             ICMPv6, UDP, and TCP Headers", RFC 4727, November 2006.
 [RFC6740]   Atkinson, R. and S. Bhatti, "Identifier-Locator Network
             Protocol (ILNP) Architectural Description", RFC 6740,
             November 2012.

Atkinson & Bhatti Experimental [Page 9] RFC 6746 ILNPv4 Opts November 2012

 [RFC6741]   Atkinson, R. and S. Bhatti, "Identifier-Locator Network
             Protocol (ILNP) Engineering and Implementation
             Considerations", RFC 6741, November 2012.
 [RFC6742]   Atkinson, R., Bhatti, S. and S. Rose, "DNS Resource
             Records for the Identifier-Locator Network Protocol
             (ILNP)", RFC 6742, November 2012.
 [RFC6745]   Atkinson, R. and S. Bhatti,  "ICMP Locator Update Message
             for the Identifier-Locator Network Protocol Version 4
             (ILNPv4)", RFC 6745, November 2012.
 [RFC6747]   Atkinson, R. and S. Bhatti, "Address Resolution Protocol
             (ARP) Extension for the Identifier-Locator Network
             Protocol Version 4 (ILNPv4)", RFC 6747, November 2012.

5.2. Informative References

 [FILTERING] Gont, F., Atkinson, R., and C. Pignataro,
             "Recommendations on filtering of IPv4 packets containing
             IPv4 options", Work in Progress, March 2012.
 [RFC2780]   Bradner, S. and V. Paxson, "IANA Allocation Guidelines
             For Values In the Internet Protocol and Related Headers",
             BCP 37, RFC 2780, March 2000.
 [RFC2827]   Ferguson, P. and D. Senie, "Network Ingress Filtering:
             Defeating Denial of Service Attacks which employ IP
             Source Address Spoofing", BCP 38, RFC 2827, May 2000.
 [RFC3704]   Baker, F. and P. Savola, "Ingress Filtering for
             Multihomed Networks", BCP 84, RFC 3704, March 2004.
 [RFC4086]   Eastlake 3rd, D., Schiller, J., and S. Crocker,
             "Randomness Requirements for Security", BCP 106, RFC
             4086, June 2005.
 [RFC4984]   Meyer, D., Ed., Zhang, L., Ed., and K. Fall, Ed., "Report
             from the IAB Workshop on Routing and Addressing", RFC
             4984, September 2007.
 [RFC6743]   Atkinson, R. and S. Bhatti, "ICMP Locator Update Message
             for the Identifier-Locator Network Protocol Version 6
             (ICMPv6)", RFC 6743, November 2012.
 [RFC6744]   Atkinson, R. and S. Bhatti, "IPv6 Nonce Destination
             Option for the Identifier-Locator Network Protocol
             Version 6 (ILNPv6)", RFC 6744, November 2012.

Atkinson & Bhatti Experimental [Page 10] RFC 6746 ILNPv4 Opts November 2012

 [RFC6748]   Atkinson, R. and S Bhatti, "Optional Advanced Deployment
             Scenarios for the Identifier-Locator Network Protocol
             (ILNP)", RFC 6748, November 2012.

6. Acknowledgements

 Steve Blake, Stephane Bortzmeyer, Mohamed Boucadair, Noel Chiappa,
 Wes George, Steve Hailes, Joel Halpern, Mark Handley, Volker Hilt,
 Paul Jakma, Dae-Young Kim, Tony Li, Yakov Rehkter, Bruce Simpson,
 Robin Whittle and John Wroclawski (in alphabetical order) provided
 review and feedback on earlier versions of this document.  Steve
 Blake provided an especially thorough review of an early version of
 the entire ILNP document set, which was extremely helpful.  We also
 wish to thank the anonymous reviewers of the various ILNP papers for
 their feedback.
 Roy Arends provided expert guidance on technical and procedural
 aspects of DNS issues.

Authors' Addresses

 RJ Atkinson
 Consultant
 San Jose, CA 95125
 USA
 EMail: rja.lists@gmail.com
 SN Bhatti
 School of Computer Science
 University of St Andrews
 North Haugh, St Andrews
 Fife, Scotland
 KY16 9SX, UK
 EMail: saleem@cs.st-andrews.ac.uk

Atkinson & Bhatti Experimental [Page 11]

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