DHC WG X. Zhou Internet-Draft ZTE Corporation Intended status: Standards Track October 11, 2012 Expires: April 14, 2013 DHCPv4 and DHCPv6 options for GRE draft-zhou-dhc-gre-option-00 Abstract This document specifies how the Generic Routing Encapsulation parameters are exchanged using Dynamic Host Configuration Protocol (DHCPv4 and DHCPv6) signaling in an IP network. 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 April 14, 2013. 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. 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. Zhou Expires April 14, 2013 [Page 1] Internet-Draft DHCPv4 and DHCPv6 options for GRE October 2012 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Convention and Terminology . . . . . . . . . . . . . . . . . . 4 3. GRE Key Option for DHCPv4 . . . . . . . . . . . . . . . . . . 5 4. GRE Key Option for DHCPv6 . . . . . . . . . . . . . . . . . . 6 5. Option Usage . . . . . . . . . . . . . . . . . . . . . . . . . 7 5.1. Usage of GRE Key Option for DHCPv4 . . . . . . . . . . . . 7 5.1.1. Mobile Node Behavior . . . . . . . . . . . . . . . . . 7 5.2. Usage of GRE Key Option for DHCPv6 . . . . . . . . . . . . 7 5.2.1. Mobile Node Behavior . . . . . . . . . . . . . . . . . 7 6. Security Considerations . . . . . . . . . . . . . . . . . . . 9 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 8. Normative References . . . . . . . . . . . . . . . . . . . . . 11 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 12 Zhou Expires April 14, 2013 [Page 2] Internet-Draft DHCPv4 and DHCPv6 options for GRE October 2012 1. Introduction There are scenarios where the point-to-point access link types are required to be supported. For example, Proxy Mobile IPv6 [RFC5213] supports only point-to-point access link types which assumes that the mobile node and mobile access gateway are the only two nodes on the access link. In this case, both IP layer and layer-2 point-to-point can be used for this requirement. When there is IP routed node being deployed between the two point-to-point nodes, only IP layer point- to-point mode can be used. In this case, Generic Routing Encapsulation (GRE) [RFC2784] is one of ideal IP layer modes which can be used to implementate layer-3 point-to-point link. In other hand, DHCP is widely used to assign configuration parameters in addtion to IP address. This document defines new Dynamic Host Configuration Protocol (DHCPv4 and DHCPv6) options to enable a mobile node to obtain the dynamically assigned Generic Routing Encapsulation key. In this way, the mobile node achieves to negotiate the uplink/downlink GRE key via DHCP signaling. In this specification, it assumes that the DHCP server makes sure the corresponding GRE tunnel endpoint can obtain the negotiated GRE key if DHCP server is not co-located with the corresponding GRE tunnel endpoint. Zhou Expires April 14, 2013 [Page 3] Internet-Draft DHCPv4 and DHCPv6 options for GRE October 2012 2. Convention and 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]. The following term used in this document. Uplink GRE Key The GRE key is assigned by the DHCP server and used by the mobile node, i.e. DHCP client to mark the uplink traffic that belongs to a specific IP connection as described in this specification. Downlink GRE Key The GRE key is assigned by the DHCP client and used by the corresponding GRE tunnel endpoint to mark the downlink traffic that belongs to a specific IP connection as described in this specification. In current specification, it is optional for the mobile node i.e. DHCP client side to assign the downlink GRE key. If the DHCP cilent does not set the value of the downlink GRE key in the option, it is considered that the value of the downlink GRE key is equal to the value of uplink GRE key by default. Thus, both the uplink GRE key and downlink GRE key are used to identify the specific IP connection which are unique within the scope of the DHCP client side. Zhou Expires April 14, 2013 [Page 4] Internet-Draft DHCPv4 and DHCPv6 options for GRE October 2012 3. GRE Key Option for DHCPv4 This section describes the GRE Key Option for DHCPv4. The option layout is depicted below: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Option Code | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | GRE Key Identifier | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Option Code OPTION-IPv4_GREKEY(To be assigned). Length 8-bit unsigned integer indicating the length of the option in octets, excluding the Option Code and length fields. GRE Key Identifier A four-byte field containing the GRE key identifier as specified in [RFC2890]. Zhou Expires April 14, 2013 [Page 5] Internet-Draft DHCPv4 and DHCPv6 options for GRE October 2012 4. GRE Key Option for DHCPv6 This section describes the GRE Key Option for DHCPv6. The option layout is depicted below: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Option Code | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | GRE Key Identifier | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Option Code OPTION-IPv6_GREKEY(To be assigned). Length 16-bit unsigned integer indicating the length of the option in octets, excluding the Option Code and length fields. GRE Key Identifier A four-byte field containing the GRE key identifier as specified in [RFC2890]. Zhou Expires April 14, 2013 [Page 6] Internet-Draft DHCPv4 and DHCPv6 options for GRE October 2012 5. Option Usage 5.1. Usage of GRE Key Option for DHCPv4 The requesting and sending of the proposed DHCPv4 options follow the rules for DHCP options in [RFC2131]. 5.1.1. Mobile Node Behavior In order to request for GRE Key exchanging, the mobile node (i.e. DHCP client) MUST include a GRE Key option in the Parameter Request List (PRL) in the respective DHCP messages as defined in [RFC2131] and [RFC2132]. The DHCP client MAY initiate a new DHCP exchange or piggyback on other DHCP message exchanges. DHCP client-handling PRL options are specified in [RFC2131], Section 4.4. If the mobile node include GRE Key option and set 0 in the GRE Key identifier field, it indicates that the downlink GRE key has the same value with the uplink GRE key. If the mobile node include GRE Key option and set non-zero in the GRE Key identifier field, it explicitly assigns the downlink GRE key to the corresponding GRE tunnel endpoint. In this specification, the GRE Key identifier field is set 0 by default. If the mobile node receives the DHCP message sent by the DHCPv4 server without GRE key option, the mobile node MUST consider that the DHCPv4 server does not support the GRE Key option and MUST not include the GRE Key option in the subsequent DHCPv4 message. 5.2. Usage of GRE Key Option for DHCPv6 The requesting and sending of the proposed DHCPv6 options follow the rules for DHCP options in [RFC3315]. 5.2.1. Mobile Node Behavior In order to request for GRE Key exchanging, the mobile node (i.e. DHCP client) MUST include a GRE Key option in the Option Request Option (ORO) in the respective DHCP messages as defined in [RFC3315]. The DHCP client MAY initiate a new DHCP exchange or piggyback on other DHCP message exchanges. DHCP client-handling ORO options are specified in [RFC3315], Section 17.1 and 18.1. If the mobile node include GRE Key option and set 0 in the GRE Key identifier field, it indicates that the downlink GRE key has the same value with the uplink GRE key. If the mobile node include GRE Key option and set non-zero in the GRE Key identifier field, it explicitly assigns the downlink GRE key to the corresponding GRE Zhou Expires April 14, 2013 [Page 7] Internet-Draft DHCPv4 and DHCPv6 options for GRE October 2012 tunnel endpoint. In this specification, the GRE Key identifier field is set 0 by default. If the mobile node receives the DHCP message sent by the DHCPv6 server without GRE key option, the mobile node MUST consider that the DHCPv6 server does not support the GRE Key option and MUST not include the GRE Key option in the subsequent DHCPv6 message. Zhou Expires April 14, 2013 [Page 8] Internet-Draft DHCPv4 and DHCPv6 options for GRE October 2012 6. Security Considerations TBD Zhou Expires April 14, 2013 [Page 9] Internet-Draft DHCPv4 and DHCPv6 options for GRE October 2012 7. IANA Considerations This document defines two new DHCP options as described in Sections 3 and 4. GRE Key Option for DHCPv4(OPTION-IPv4_GREKEY) TBA GRE Key Option for DHCPv6 (OPTION-IPv6_GREKEY) TBA Zhou Expires April 14, 2013 [Page 10] Internet-Draft DHCPv4 and DHCPv6 options for GRE October 2012 8. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2131] Droms, R., "Dynamic Host Configuration Protocol", RFC 2131, March 1997. [RFC2132] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor Extensions", RFC 2132, March 1997. [RFC2784] Farinacci, D., Li, T., Hanks, S., Meyer, D., and P. Traina, "Generic Routing Encapsulation (GRE)", RFC 2784, March 2000. [RFC2890] Dommety, G., "Key and Sequence Number Extensions to GRE", RFC 2890, September 2000. [RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., and M. Carney, "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)", RFC 3315, July 2003. [RFC5213] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K., and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008. Zhou Expires April 14, 2013 [Page 11] Internet-Draft DHCPv4 and DHCPv6 options for GRE October 2012 Author's Address Xingyue Zhou ZTE Corporation No.50 Software Avenue, Yuhuatai District Nanjing China Phone: +86-25-8801-4634 Email: zhou.xingyue@zte.com.cn Zhou Expires April 14, 2013 [Page 12]