Internet DRAFT - draft-ietf-ipsecme-ipv6-ipv4-codes

draft-ietf-ipsecme-ipv6-ipv4-codes







ipsecme                                                     M. Boucadair
Internet-Draft                                                    Orange
Updates: 7296 (if approved)                            December 17, 2020
Intended status: Standards Track
Expires: June 20, 2021


       IKEv2 Notification Status Types for IPv4/IPv6 Coexistence
                 draft-ietf-ipsecme-ipv6-ipv4-codes-06

Abstract

   This document specifies new IKEv2 notification status types to better
   manage IPv4 and IPv6 co-existence by allowing the responder to signal
   to the initiator which address families are allowed.

   This document updates RFC7296.

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
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   This Internet-Draft will expire on June 20, 2021.

Copyright Notice

   Copyright (c) 2020 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
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   (https://trustee.ietf.org/license-info) in effect on the date of
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   include Simplified BSD License text as described in Section 4.e of




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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Why Not INTERNAL_ADDRESS_FAILURE? . . . . . . . . . . . . . .   3
   4.  IP6_ALLOWED and IP4_ALLOWED Status Types  . . . . . . . . . .   4
   5.  An Update to RFC7296  . . . . . . . . . . . . . . . . . . . .   4
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   6
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .   6
     9.2.  Informative References  . . . . . . . . . . . . . . . . .   7
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   As described in [RFC7849], if the subscription data or network
   configuration allows only one IP address family (IPv4 or IPv6), the
   cellular host must not request a second PDP-Context (Section 3.2 of
   [RFC6459]) to the same Access Point Name (APN) for the other IP
   address family (AF).  The Third Generation Partnership Project (3GPP)
   network informs the cellular host about allowed Packet Data Protocol
   (PDP) types by means of Session Management (SM) cause codes.  In
   particular, the following cause codes can be returned:

   o  cause #50 "PDP type IPv4 only allowed": This cause code is used by
      the network to indicate that only PDP type IPv4 is allowed for the
      requested Public Data Network (PDN) connectivity.

   o  cause #51 "PDP type IPv6 only allowed": This cause code is used by
      the network to indicate that only PDP type IPv6 is allowed for the
      requested PDN connectivity.

   o  cause #52 "single address bearers only allowed": This cause code
      is used by the network to indicate that the requested PDN
      connectivity is accepted with the restriction that only single IP
      version bearers are allowed.

   If the requested IPv4v6 PDP-Context is not supported by the network
   but IPv4 and IPv6 PDP types are allowed, then the cellular host will
   be configured with an IPv4 address or an IPv6 prefix by the network.
   It must initiate another PDP-Context activation of the other address
   family in addition to the one already activated for a given APN.  The
   purpose of initiating a second PDP-Context is to achieve dual-stack



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   connectivity (that is, IPv4 and IPv6 connectivity) by means of two
   PDP-Contexts.

   When the User Equipment (UE) attaches to the 3GPP network using a
   non-3GPP access network (e.g., Wireless Local Area Network (WLAN)),
   there are no equivalent Internet Key Exchange Protocol Version 2
   (IKEv2) capabilities [RFC7296] notification codes for the 3GPP
   network to inform the UE why an IP address family is not assigned or
   whether that UE should retry with another address family.

   This document fills that void by introducing new IKEv2 notification
   status types for the sake of deterministic UE behaviors (Section 4).

   These notification status types are not specific to 3GPP
   architectures, but can be used in other deployment contexts.
   Cellular networks are provided as an illustration example.

2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119][RFC8174] when, and only when, they appear in all
   capitals, as shown here.

   This document makes use of the terms defined in [RFC7296].  In
   particular, readers should be familiar with "initiator" and
   "responder" terms used in that document.

3.  Why Not INTERNAL_ADDRESS_FAILURE?

   The following address assignment failures may be encountered when an
   initiator requests assignment of IP addresses/prefixes:

   o  An initiator asks for IPvx, but IPvx address assignment is not
      supported by the responder.

   o  An initiator requests both IPv4 and IPv6 addresses, but only IPv4
      address assignment is supported by the responder.

   o  An initiator requests both IPv4 and IPv6 addresses, but only IPv6
      prefix assignment is supported by the responder.

   o  An initiator asks for both IPv4 and IPv6 addresses, but only one
      address family can be assigned by the responder for policy
      reasons.





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   Section 3.15.4 of [RFC7296] defines a generic notification error type
   (INTERNAL_ADDRESS_FAILURE) that is related to a failure to handle an
   address assignment request.  The responder sends
   INTERNAL_ADDRESS_FAILURE only if no addresses can be assigned.  This
   behavior does not explicitly allow an initiator to determine why a
   given address family is not assigned, nor whether it should try using
   another address family.  INTERNAL_ADDRESS_FAILURE is a catch-all
   error type when an address-related issue is encountered by an IKEv2
   responder.

   INTERNAL_ADDRESS_FAILURE does not provide sufficient hints to the
   IKEv2 initiator to adjust its behavior.

4.  IP6_ALLOWED and IP4_ALLOWED Status Types

   IP6_ALLOWED and IP4_ALLOWED notification status types (see Section 7)
   are defined to inform the initiator about the responder's address
   family assignment support capabilities, and to report to the
   initiator the reason why an address assignment failed.  These
   notification status types are used by the initiator to adjust its
   behavior accordingly (Section 5).

   No data is associated with these notifications.

5.  An Update to RFC7296

   If the initiator is dual-stack (i.e., supports both IPv4 and IPv6),
   it MUST include both address families configuration attributes in its
   configuration request (absent explicit policy/configuration
   otherwise).  More details about IPv4 and IPv6 configuration
   attributes are provided in Section 3.15 of [RFC7296].  These
   attributes are used to infer the requested/assigned AFs listed in
   Table 1.

   The responder MUST include IP6_ALLOWED and/or IP4_ALLOWED
   notification status type in a response to an address assignment
   request as indicated in Table 1.














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   +----------------+----------------+---------------+-----------------+
   |                |                |               |     Returned    |
   |   Requested    |   Supported    |    Assigned   |   Notification  |
   |     AF(s)      |     AF(s)      |     AF(s)     |  Status Type(s) |
   |  (Initiator)   |  (Responder)   |  (Responder)  |   (Responder)   |
   +----------------+----------------+---------------+-----------------+
   |      IPv4      |      IPv6      |      None     |   IP6_ALLOWED   |
   |      IPv4      |      IPv4      |      IPv4     |   IP4_ALLOWED   |
   |      IPv4      | IPv4 and IPv6  |      IPv4     |   IP4_ALLOWED,  |
   |                |                |               |   IP6_ALLOWED   |
   |      IPv6      |      IPv6      |      IPv6     |   IP6_ALLOWED   |
   |      IPv6      |      IPv4      |      None     |   IP4_ALLOWED   |
   |      IPv6      | IPv4 and IPv6  |      IPv6     |   IP4_ALLOWED,  |
   |                |                |               |   IP6_ALLOWED   |
   | IPv4 and IPv6  |      IPv4      |      IPv4     |   IP4_ALLOWED   |
   | IPv4 and IPv6  |      IPv6      |      IPv6     |   IP6_ALLOWED   |
   | IPv4 and IPv6  | IPv4 and IPv6  | IPv4 and IPv6 |   IP4_ALLOWED,  |
   |                |                |               |   IP6_ALLOWED   |
   | IPv4 and IPv6  |  IPv4 or IPv6  |  IPv4 or IPv6 |   IP4_ALLOWED,  |
   |                | (Policy-based) |               |   IP6_ALLOWED   |
   +----------------+----------------+---------------+-----------------+

                Table 1: Returned Notification Status Types

   If the initiator only receives one single notification IP4_ALLOWED or
   IP6_ALLOWED from the responder, the initiator MUST NOT send a
   subsequent request for an alternate address family not supported by
   the responder.

   If a dual-stack initiator requests only an IPv6 prefix (or an IPv4
   address) but only receives IP4_ALLOWED (or IP6_ALLOWED) notification
   status type from the responder, the initiator MUST send a request for
   IPv4 address(es) (or IPv6 prefix(es)).

   If a dual-stack initiator requests both an IPv6 prefix and an IPv4
   address but receives an IPv6 prefix (or an IPv4 address) only with
   both IP4_ALLOWED and IP6_ALLOWED notification status types from the
   responder, the initiator MAY send a request for the other AF (i.e.,
   IPv4 address (or IPv6 prefix)).  In such case, the initiator MUST
   create a new IKE Security Association (SA) and request that another
   address family using the new IKE SA.

   For other address-related error cases that have not been covered by
   the aforementioned notification status types, the responder/initiator
   MUST follow the procedure defined in Section 3.15.4 of [RFC7296].






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6.  Security Considerations

   Since the IPv4/IPv6 capabilities of a node are readily determined
   from the traffic it generates, this document does not introduce any
   new security considerations compared to the ones described in
   [RFC7296], which continue to apply.

7.  IANA Considerations

   This document requests IANA to update the "IKEv2 Notify Message Types
   - Status Types" registry available at:
   https://www.iana.org/assignments/ikev2-parameters/
   ikev2-parameters.xhtml with the following status types:

   Value           NOTIFY MESSAGES - STATUS TYPES     Reference
    TBD                   IP4_ALLOWED                 [This-Document]
    TBD                   IP6_ALLOWED                 [This-Document]

8.  Acknowledgements

   Many thanks to Christian Jacquenet for the review.

   Thanks to Paul Wouters, Yaov Nir, Valery Smyslov, Daniel Migault,
   Tero Kivinen, and Michael Richardson for the comments and review.

   Thanks to Benjamin Kaduk for the AD review.

   Thanks to Murray Kucherawy, Eric Vyncke, and Robert Wilton for the
   IESG review.

9.  References

9.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC7296]  Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T.
              Kivinen, "Internet Key Exchange Protocol Version 2
              (IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October
              2014, <https://www.rfc-editor.org/info/rfc7296>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.




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9.2.  Informative References

   [RFC6459]  Korhonen, J., Ed., Soininen, J., Patil, B., Savolainen,
              T., Bajko, G., and K. Iisakkila, "IPv6 in 3rd Generation
              Partnership Project (3GPP) Evolved Packet System (EPS)",
              RFC 6459, DOI 10.17487/RFC6459, January 2012,
              <https://www.rfc-editor.org/info/rfc6459>.

   [RFC7849]  Binet, D., Boucadair, M., Vizdal, A., Chen, G., Heatley,
              N., Chandler, R., Michaud, D., Lopez, D., and W. Haeffner,
              "An IPv6 Profile for 3GPP Mobile Devices", RFC 7849,
              DOI 10.17487/RFC7849, May 2016,
              <https://www.rfc-editor.org/info/rfc7849>.

Author's Address

   Mohamed Boucadair
   Orange
   Rennes  35000
   France

   Email: mohamed.boucadair@orange.com





























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