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Versions: 00 01 02 03 rfc6028                                           
HIP Working Group                                           G. Camarillo
Internet-Draft                                                A. Keranen
Intended status: Experimental                                   Ericsson
Expires: September 9, 2010                                 March 8, 2010


        Host Identity Protocol (HIP) Multi-hop Routing Extension
                       draft-ietf-hip-via-01.txt

Abstract

   This document specifies two extensions to HIP to implement multi-hop
   routing.  The first extension allows implementing source routing in
   HIP.  That is, a host sending a HIP packet can define a set of hosts
   that the HIP packet should traverse.  The second extension allows a
   HIP packet to carry and record the list of hosts that forwarded it.

Status of this Memo

   This Internet-Draft is submitted to IETF in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
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   Drafts.

   Internet-Drafts are draft documents valid for a maximum of six months
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   This Internet-Draft will expire on September 9, 2010.

Copyright Notice

   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



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   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 BSD License.


Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3
     2.1.  Requirements Language . . . . . . . . . . . . . . . . . . . 3
     2.2.  Definitions . . . . . . . . . . . . . . . . . . . . . . . . 3
   3.  Protocol Definitions  . . . . . . . . . . . . . . . . . . . . . 4
     3.1.  Creating and Processing Via Lists . . . . . . . . . . . . . 4
     3.2.  Creating Destination Lists  . . . . . . . . . . . . . . . . 4
     3.3.  Processing Destination Lists  . . . . . . . . . . . . . . . 5
   4.  Packet Formats  . . . . . . . . . . . . . . . . . . . . . . . . 5
     4.1.  Source and Destination Route List Parameters  . . . . . . . 6
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7
   6.  Security Considerations . . . . . . . . . . . . . . . . . . . . 7
   7.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 8
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 8
     8.1.  Normative References  . . . . . . . . . . . . . . . . . . . 8
     8.2.  Informative References  . . . . . . . . . . . . . . . . . . 8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 8
























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1.  Introduction

   When HIP [RFC5201] is used in certain contexts, hosts need the
   ability to perform source routing.  That is, a host needs the ability
   to send a HIP packet that will traverse a set of hosts before
   reaching its destination.  Such features are needed, e.g., in HIP
   BONE [I-D.ietf-hip-bone] overlay networks or if two hosts wish to
   keep a third, or more, HIP hosts on the signaling path.  This
   document defines an extension that provides HIP with this
   functionality.

   Additionally, when HIP packets are routed through multiple hosts,
   some of these hosts (e.g., the destination host) need the ability to
   know the hosts a particular packet traversed.  This document defines
   another extension that provides HIP with this functionality.

   These two extensions enable multi-hop routing in HIP.  Before these
   extensions were specified, there were standardized ways for
   supporting only a single intermediate host (e.g., a rendezvous server
   [RFC5204]) between the source of a HIP packet and its destination.


2.  Terminology

2.1.  Requirements Language

   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 [RFC2119].

2.2.  Definitions

   The following terms used in this document are similar to those
   defined by RELOAD [I-D.ietf-p2psip-base] but used here in context of
   HIP.

   Destination list:  A list of HITs of the hosts that a HIP packet
      should traverse.

   Via list:  A list of HITs of the hosts that a HIP packet has
      traversed.

   Symmetric routing:  A response to a message is routed back using the
      same set of intermediary nodes as the original message used,
      except in reversed order.  Also known as symmetric recursive
      routing.





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3.  Protocol Definitions

   The multi-hop routing extensions may be used in different contexts
   and whether a new HIP packet should, for example, include a Via list
   or have different options enabled, can depend on the particular use
   case, local policies, and different protocols using the extension.
   This section defines how the new parameters are handled, but when to
   use these extensions is out of scope for this document.

3.1.  Creating and Processing Via Lists

   When a host sending a HIP packet needs to record the hosts that are
   on the path that the HIP packet traverses, it includes an empty
   ROUTE_VIA parameter to the packet.

   A host that receives a packet with a ROUTE_VIA parameter SHOULD add
   its own HIT to the end of the ROUTE_VIA parameter, unless it is the
   receiver of the packet.  If the host uses a different HIT on the HIP
   association it used for receiving the packet than for sending it
   forward, it SHOULD also add the receiving HIT to the route list
   before the sending HIT.

   If the host is the receiver of the packet, and the received packet
   generates a response HIP packet, the host checks the SYMMETRIC flag
   from the ROUTE_VIA parameter.  If the SYMMETRIC flag is set, the host
   MUST create a ROUTE_DST parameter from the ROUTE_VIA parameter, as
   described in Section 3.2, and include it in the response packet.
   Also, if an intermediary host generates a new HIP packet (e.g., an
   error NOTIFY packet) due to a HIP packet that had a ROUTE_VIA
   parameter with SYMMETRIC flag set, and the new packet is intended for
   the sender of the original HIP packet, the host SHOULD construct and
   add a ROUTE_DST parameter into the new packet as in the previous
   case.

3.2.  Creating Destination Lists

   A host that needs to define the other hosts that should be on the
   path a HIP packet traverses adds a ROUTE_DST parameter to the HIP
   packet.  The host may either decide the path independently, or it may
   create the path based on a ROUTE_VIA parameter.  Only the originator
   of a signed HIP packet can add a ROUTE_DST parameter to the HIP
   packet since the parameter is covered by the signature.

   When a host creates a ROUTE_DST parameter due to receiving a packet
   with a ROUTE_VIA parameter, it copies all the HITs in the ROUTE_VIA
   parameter to the ROUTE_DST parameter, but in reversed order.  This
   results in HIP response packet being forwarded using the same set of
   hosts as the packet for which the response was generated for.



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3.3.  Processing Destination Lists

   When a host receives a HIP packet that contains a ROUTE_DST
   parameter, it first looks up its own HIT from the route list.  If
   host's own HIT is not in the list and the host is not the receiver of
   the packet, the packet was incorrectly forwarded and MUST be dropped.
   If the host's HIT is in the list more than once, the list is invalid
   and the packet MUST be dropped to avoid forwarding loops.  Next hop
   for the packet is the HIT after host's own HIT in the list.  If the
   host's HIT was the last HIT in the list, the next hop is the
   receiver's HIT in the HIP header.

   If the MUST_FOLLOW flag in the ROUTE_DST parameter is not set, the
   host SHOULD check whether it has a valid locator for one of the hosts
   later in the list, or for the receiver of the packet, and it MAY
   select such a host as the next hop.  If the MUST_FOLLOW flag is set,
   the host MUST NOT skip any hosts in the list.

   If the host has a valid locator for the next hop, it MUST forward the
   HIP packet to the next hop host.  If the host can not determine a
   valid locator for the next hop host, it SHOULD drop the packet and
   SHOULD send back a NOTIFY error packet with type UNKNOWN_NEXT_HOP
   (value [TBD by IANA; 90]).  The Notification Data field for the error
   notifications SHOULD contain the HIP header of the rejected packet
   and the ROUTE_DST parameter.


4.  Packet Formats

   This memo defines two new HIP parameters that are used for recording
   a route via multiple hosts (ROUTE_VIA) and for defining a route a
   packet should traverse by the sender of the packet (ROUTE_DST).

   The ROUTE_DST parameter is integrity protected with the signature
   (where present) but ROUTE_VIA is not so that intermediary hosts can
   add their own HITs to the list.  Both parameters have critical type
   (as defined in Section 5.2.1 of [RFC5201]) since the packet will not
   be properly routed unless all hosts on path recognize the parameters.













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4.1.  Source and Destination Route List Parameters

      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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |             Type              |             Length            |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |             Flags             |            Reserved           |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                                                               |
     |                            HIT #1                             |
     |                                                               |
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     .                               .                               .
     .                               .                               .
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                                                               |
     |                            HIT #n                             |
     |                                                               |
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


     Type      [ TBD by IANA
               ROUTE_DST: 971
               ROUTE_VIA: 65525 ]
     Length    length in octets, excluding Type and Length
               (i.e., number-of-HITs * 16 + 4)
     Flags     bit flags that can be used for requesting special
               handling of the parameter
     Reserved  reserved for future use
     HIT       Host Identity Tag of one of the hosts on the path

        Figure 1: Format of the ROUTE_VIA and ROUTE_DST Parameters

   Figure 1 shows the format of both ROUTE_VIA and ROUTE_DST parameters.
   The ROUTE_DST parameter, if present, MUST have at least one HIT, but
   the ROUTE_VIA parameter can also have zero HITs.  Both can contain at
   most 32 HITs.  The Flags field is used for requesting special
   handling for via and destination lists.  The flags defined in this
   document are shown in Table 1.  The Reserved field can be used by
   future extensions; it MUST be zero when sending and ignored when
   receiving this parameter.







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   +-----+-------------+-----------------------------------------------+
   | Pos | Name        | Purpose                                       |
   +-----+-------------+-----------------------------------------------+
   |  0  | SYMMETRIC   | The response packet MUST be sent with a       |
   |     |             | ROUTE_DST list made from the ROUTE_VIA list   |
   |     |             | containing this flag, i.e., using symmetric   |
   |     |             | routing.                                      |
   |  1  | MUST_FOLLOW | All the hosts in a ROUTE_DST list MUST be     |
   |     |             | traversed, i.e., even if a host would have a  |
   |     |             | valid locator for a host beyond the next hop, |
   |     |             | it MUST NOT forward the packet there but to   |
   |     |             | the next hop host.                            |
   +-----+-------------+-----------------------------------------------+

         Table 1: Bit Flags in ROUTE_VIA and ROUTE_DST Parameters

   The "Pos" column in Table 1 shows the bit position of the flag (as in
   Figure 1) in the Flags field, "Name" gives the name of the flag used
   in this document, and "Purpose" gives brief description of the
   meaning of that flag.

   The flags apply to both ROUTE_VIA and ROUTE_DST parameters and when a
   ROUTE_DST parameter is added to a packet because of a ROUTE_VIA
   parameter, the same flags MUST be copied to the ROUTE_DST parameter.


5.  IANA Considerations

   This section is to be interpreted according to [RFC5226].

   This document updates the IANA Registry for HIP Parameter Types
   [RFC5201] by assigning new HIP Parameter Type values for the new HIP
   Parameters: ROUTE_VIA and ROUTE_DST (defined in Section 4).  This
   document also defines a new Notify Packet Type [RFC5201]
   UNKNOWN_NEXT_HOP in Section 3.3.


6.  Security Considerations

   A malicious host could craft a destination route list that contains
   the same HIT more than once and thus create a forwarding loop.  The
   check described in Section 3.3 should break such loops but hosts MAY
   in addition utilize the OVERLAY_TTL [I-D.ietf-hip-bone] parameter for
   additional protection against forwarding loops.







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7.  Acknowledgments

   Tom Henderson provided valuable comments and improvement suggestions
   for this document.


8.  References

8.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC5201]  Moskowitz, R., Nikander, P., Jokela, P., and T. Henderson,
              "Host Identity Protocol", RFC 5201, April 2008.

8.2.  Informative References

   [RFC5204]  Laganier, J. and L. Eggert, "Host Identity Protocol (HIP)
              Rendezvous Extension", RFC 5204, April 2008.

   [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", BCP 26, RFC 5226,
              May 2008.

   [I-D.ietf-hip-bone]
              Camarillo, G., Nikander, P., Hautakorpi, J., Keranen, A.,
              and A. Johnston, "HIP BONE: Host Identity Protocol (HIP)
              Based Overlay Networking Environment",
              draft-ietf-hip-bone-04 (work in progress), January 2010.

   [I-D.ietf-p2psip-base]
              Jennings, C., Lowekamp, B., Rescorla, E., Baset, S., and
              H. Schulzrinne, "REsource LOcation And Discovery (RELOAD)
              Base Protocol", draft-ietf-p2psip-base-07 (work in
              progress), February 2010.


Authors' Addresses

   Gonzalo Camarillo
   Ericsson
   Hirsalantie 11
   02420 Jorvas
   Finland

   Email: Gonzalo.Camarillo@ericsson.com




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   Ari Keranen
   Ericsson
   Hirsalantie 11
   02420 Jorvas
   Finland

   Email: Ari.Keranen@ericsson.com












































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