Network Working Group
J. Pezeshki Internet-DraftE. Ertekin Internet-Draft C. Christou Expires: February 16,April 17, 2009 R. Jasani C. ChristouJ. Pezeshki Booz Allen Hamilton August 15,October 14, 2008 IKEv2 Extensions to Support Robust Header Compression over IPsec (RoHCoIPsec) draft-ietf-rohc-ikev2-extensions-hcoipsec-06(ROHCoIPsec) draft-ietf-rohc-ikev2-extensions-hcoipsec-07 Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. 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. 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/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on February 16,April 17, 2009. Abstract In order to integrate RoHCROHC with IPsec [ROHCOIPSEC], a mechanism is needed to negotiate RoHCROHC configuration parameters between end-points. Internet Key Exchange (IKE) is a mechanism which can be leveraged to handle these negotiations. This document specifies extensions to IKEv2 [IKEV2] that will allow RoHCROHC and its associated configuration parameters to be negotiated for IPsec security associations (SAs). Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. RoHCROHC Channel Negotiation . . . . . . . . . . . . . . . . . . . 3 2.1. Negotiation of RoHCROHC Channel Parameters . . . . . . . . . . 3 3. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 5. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 76 6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 6.1. Normative References . . . . . . . . . . . . . . . . . . . 7 6.2. Informative References . . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8 Intellectual Property and Copyright Statements . . . . . . . . . . 9 1. Introduction Increased packet header overhead due to IPsec [IPSEC] can result in the inefficient utilization of bandwidth. Coupling RoHCROHC [ROHC] with IPsec offers an efficient way to transfer protected IP traffic. The operation of RoHCoIPsecROHCoIPsec [ROHCOIPSEC] requires configuration parameters to be negotiated between the compressor and decompressor. Current specifications for hop-by-hop RoHCROHC negotiate these parameters through a link-layer protocol such as Point-to-Point Protocol (PPP) (i.e. RoHCROHC over PPP [ROHCPPP]). Since key exchange protocols (e.g. IKEv2) can be used to negotiate parameters between IPsec peers, this document defines extensions to IKEv2 to negotiate RoHCROHC parameters for RoHCoIPsec.ROHCoIPsec. 2. RoHCROHC Channel Negotiation The initialization of a RoHCROHC session requires the negotiation of a set of configuration parameters (e.g. MAX_CID, PROFILES, etc.). The following subsections define extensions to IKEv2 which enables an initiator to propose a set of RoHCROHC parameters; the responder selects the appropriate parameters from this list, and responds with the accepted parameters for the RoHCROHC channel. 2.1. Negotiation of RoHCROHC Channel Parameters RoHCROHC configuration parameters will be negotiated at either the establishment or rekeying of a Child SA. Specifically, a new Notify payloadmessage type is used during the IKE_AUTH and CREATE_CHILD_SA exchanges to negotiate these parameters. The Notify payload sent by the initiator contains the configuration parameters for the RoHCROHC implementation. Upon receipt of the initiator's request, the responder will either ignore the payload (if it doesn't support RoHCROHC or the proposed parameters) or respond with a Notify payload that contains the accepted RoHCROHC channel parameters. The accepted parameters are an intersection between the parameters proposed by the initiator and the parameters supported by the responder (e.g. if the initiator proposes a MAX_CID value of 15, but the responder only supports a MAX_CID value of 13, the responder will respond with a value of 13, which is supported by both parties). Note that only one Notify payload is used to convey RoHCROHC parameters per exchange. If multiple Notify payloads relaying RoHCROHC parameters are received by the responder, all but the first such Notify payload must be dropped. If the initiator does not receive a Notify Payload with the responder's accepted RoHCROHC channel parameters, RoHCROHC must not be enabled on the Child SA. A new Notify Message Type value, denoted ROHC_SUPPORTED, will be added toindicate that the Notify payload is conveying RoHCROHC channel parameters. Additionally, several fields of theThe Notify payloadPayload (as defined in [IKEV2]) is illustrated in Figure 1 below: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ! Next Payload !C! RESERVED ! Payload Length ! +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ! Protocol ID ! SPI Size ! Notify Message Type ! +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ! ! ~ Security Parameter Index (SPI) ~ ! ! +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ! ! ~ Notification Data ~ ! ! +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1. Notify Payload format. The fields of the Notify Payload are set as follows: CriticalNext Payload (1 bit) This value is set to zero to indicate thatoctet) Identifier for the recipient must skip thispayload if it does not understandtype of the next payload type codein the Next Payload field of the previous payload. RESERVED (7 bits) Mustmessage. Further details can be sent as zero, andfound in [IKEV2]. Critical (1 bit) Since all IKEv2 implementations must be ignored on receipt.support the Notify Payload, this value is zero. Protocol ID (1 octet) IfSince this Notification message is used during the RoHC parameters are set at SA creation,creation of a Child SA, this field must be set to zero. If this notification concerns an existing SA, this value may be set to (2) AH [AH], or (3) ESP [ESP].SPI Size (1 octet) This value must be set to zero, since no SPI is applicable (RoHC(ROHC parameters are set at SA creation, thus the SPI has not been defined). Notify Message Type (2 octets) This field must be set to ROHC_SUPPORTED. RoHCROHC configuration parameters will be communicated via a new Notify message type, denoted ROHC_SUPPORTED. The RoHCROHC configuration parameters will be listed within the Notification Data field of the Notify payload in the following format (default values for the configuration parameters are consistent with [ROHCPPP]): 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ! MAX_CID ! MRRU ! +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ! MAX_HEADER ! PROFILE LENGTH !| RESERVED |PROFILES_LENGTH! +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ! ! ~ PROFILES... ~ ! ! +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ! ! ~ INTEGRITY ALGORITHMS... ~ ! ! +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1.2. Notification Data field for the ROHC_SUPPORTED Notify message type. MAX_CID (2 octets) The MAX_CID field indicates the maximum value of a context identifier. This value must be at least 0 and at most 16383 (The value 0 implies having one context). Suggested value: 15 Note:PROFILES_LENGTH (1 octet) The value of LARGE_CIDS will be implicitly determined by this value (i.e. if MAX_CID is <= 15, LARGE_CIDS will be assumed to be 0). MRRU (2 octets) The MRRU field indicates the maximum reconstructed reception unit (see [ROHC], section 5.1.1). Suggested value: 0 The MRRU value is used in conjunction with the segmentation protocol defined in RoHC. Since RoHC is implemented over an IPsec SA, RoHC segmentation is not possible. Therefore, the MRRU value must be set to zero, indicating that no segment headers are allowed on the channel. MAX_HEADER (2 octets) The largest header size in octets that may be compressed. Suggested value: 168 octets Note: The MAX_HEADER parameter is not used for all RoHC profiles. If none of the RoHC profiles require this field, this value is ignored. PROFILE LENGTH (2 octets) The total numbertotal number of profiles contained within the PROFILES field (note that each RoHCROHC profile is 2-octets in length). PROFILES (variable) The set of profiles to be enabled for the RoHCROHC process. Profiles are further detailed in [ROHC]. In addition, several common profiles are defined in [ROHCPROF]. These 16-bit profile identifiers are to be sent in network byte order. INTEGRITY ALGORITHMS The set of Integrity Algorithms that may be use to ensure the integrity of the decompressed packets (i.e. ensure that the packet headers are properly decompressed). Each Integrity Algorithm is represented by a 2-octet value that corresponds to the value listed in [IKEV2-PARA] "For Transform Type 3 (Integrity Algorithm)" section. It is noted that: 1. The length of this field is inferred from the Notify Payload's "Payload Length" field ([IKEV2], Section 3.10).field. 2. The key for this Integrity Algorithm is computed using the same method as is used to compute IPsec's Integrity Algorithm key ([IKEV2], Section 2.17). 3. A ROHCoIPsec implementation may choose to negotiate a value of "0" in this field (i.e., NONE, as defined in the Integrity Algorithm Transform ID registry). The negotiated set of ROHC parameters are associated with the inbound/outbound pair of SAs established by each IKEv2 CREATE_CHILD_SA exchange. The following ROHC channel parameters are not negotiated: o LARGE_CIDS: This value is implicitly determined by the value of MAX_CID (e.g. if MAX_CID is <= 15, LARGE_CIDS is assumed to be 0). o MRRU: IPsec implementations will always implement path MTU discovery; therefore, ROHC packets will never need to use ROHC segmentation over an IPsec SA. As a result, this value will always be zero, and does not need to be negotiated. o FEEDBACK_FOR: When a pair of SAs are created (one in each direction), the RoHCROHC channel parameter FEEDBACK_FOR is set implicitly to the other SA of the pair (i.e. the SA pointing in the reverse direction). 3. Security Considerations The RoHCROHC channel parameters negotiated via IKEv2 do not add any new vulnerabilities beyond those associated with the normal operation of IKEv2. 4. IANA Considerations This document defines a new Notify Message (Status Type). Therefore, IANA is requested to allocate one value from the IKEv2 Notify Message registry to indicate ROHC_SUPPORTED. Note that, since this Notify Message is a Status Type, values ranging from 0 to 16383 must not be allocated for ROHC_SUPPORTED. 5. Acknowledgments The authors would like to thank Mr. Sean O'Keeffe, Mr. James Kohler, and Ms. Linda Noone of the Department of Defense, as well as Mr. Rich Espy of OPnet for their contributions and support in the development of this document. The authors would also like to thank Mr. Tero Kivinen for providing his technical expertise for this document. In addition, the authors would like to thank the following for their numerous reviews and comments to this document: o Dr. Stephen Kent o Dr. Carsten Bormann o Mr. Lars-Erik Jonnson o Mr. Pasi Eronen o Dr. Joseph Touch o Mr. Yoav Nir Finally, the authors would also like to thank Mr. Tom Conkle, Ms. Michele Casey, and Mr. Etzel Brower. 6. References 6.1. Normative References [ROHCOIPSEC] Ertekin, E., Christou, C., and R. Jasani, "Integration of Robust Header Compression over IPsec Security Associations", work in progress , October 2008. [ROHC] Bormann, C., Burmeister, C., Degermark, M., Fukushima, H., Hannu, H., Jonsson, L., Hakenberg, R., Koren, T., Le, K., Liu, Z., Martensson, A., Miyazaki, A., Svanbro, K., Wiebke, T., Yoshimura, T., and H. Zheng, "RObust Header Compression (ROHC): Framework and four profiles: RTP, UDP, ESP, and uncompressed", RFC 3095, July 2001. [IPSEC] Kent, S. and K. Seo, "Security Architecture for the Internet Protocol", RFC 4301, December 2005. [ROHCOIPSEC] Ertekin, E., Christou, C., and R. Jasani, "Integration of Robust Header Compression over IPsec Security Associations", work in progress , June 2006.[IKEV2] Kaufman, C., "Internet Key Exchange (IKEv2) Protocol", RFC 4306, December 2005. [ROHCPPP] Bormann, C., "Robust Header Compression (ROHC) over PPP", RFC 3241, April 2002. [AH] Kent, S., "IP Authentication Header", RFC 4302, December 2005. [ESP] Kent, S., "IP Encapsulating Security Payload (ESP)", RFC 4303, December 2005.6.2. Informative References [ROHCPROF] Pelletier, G. and K. Sandlund, "RObust Header Compression Version 2 (RoHCv2):(ROHCv2): Profiles for RTP, UDP, IP, ESP and UDP Lite", www.iana.org/assignments/ROHC-pro-ids , May 2007. [IKEV2-PARA] IANA, "IKEv2 Parameters, http://www.iana.org/assignments/ikev2-parameters", January 2008. Authors' Addresses Jonah PezeshkiEmre Ertekin Booz Allen Hamilton 13200 Woodland Park Dr. Herndon, VA 20171 US Email: email@example.com Emre Ertekinertekin_emre@bah.com Chris Christou Booz Allen Hamilton 13200 Woodland Park Dr. Herndon, VA 20171 US Email: firstname.lastname@example.org_chris@bah.com Rohan Jasani Booz Allen Hamilton 13200 Woodland Park Dr. Herndon, VA 20171 US Email: email@example.com Chris ChristouJonah Pezeshki Booz Allen Hamilton 13200 Woodland Park Dr. Herndon, VA 20171 US Email: firstname.lastname@example.org_jonah@bah.com Full Copyright Statement Copyright (C) The IETF Trust (2008). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. 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