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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.
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This Internet-Draft will expire on February 19, 2009.
This document describes the need for an interface between Mobile IPv6 and IPsec/IKE and show how the two protocols can interwork. An extension of the PF_KEY framework is proposed which allows smooth and solid operation of IKE in a Mobile IPv6 environment.
This document is heavily based on a previous draft [MIGRATE] written by Shinta Sugimoto, Masahide Nakamura and Francis Dupont. It simply reuses the MIGRATE mechanism defined in the expired document, removes a companion extension (SADB_X_EXT_PACKET) based on implementation feedback (complexity, limitations, ...) and fills the gap by very simple changes to MIGRATE mechanism. This results in a more simple and consistent mechanism, which also proved to be easier to implement. This document is expected to serve as a continuation of [MIGRATE] work. For that reason, the name of the extension has been kept.
PF_KEY MIGRATE message serves as a carrier for updated address information for both the in-kernel IPsec structures (SP/SA) and those maintained by the key managers. This includes in-kernel SP/SA endpoints, key manager maintained equivalents and addresses used by IKE_SA (current and to be negotiated). The extension is helpful for assuring smooth internetworking between Mobile IPv6 and IPsec/IKE for the bootstrapping of mobile nodes and their movements.
1.
Introduction
2.
Terminology
3.
Needs for Interactions between Mobile IPv6 and IPsec/IKE
4.
Requirements
5.
PF_KEY Extensions for Mobile IPv6: PF_KEY MIGRATE Message
5.1.
Overview
5.1.1.
System Overview
5.1.2.
Bootstrapping
5.1.3.
Movement
5.1.4.
IKE_SA Update
5.2.
Issuing PF_KEY MIGRATE Message
5.3.
Processing PF_KEY MIGRATE Message
5.4.
Applicability of PF_KEY MIGRATE to Other Systems
5.5.
NAT Traversal
5.6.
Limitations of PF_KEY MIGRATE
6.
Necessary Modifications to Mobile IPv6 and IPsec/IKE
7.
Security Considerations
8.
Conclusion
9.
References
9.1.
Normative References
9.2.
Informative References
Appendix A.
PF_KEY MIGRATE Message Format
Appendix B.
Acknowledgements
§
Authors' Addresses
§
Intellectual Property and Copyright Statements
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In Mobile IPv6 (Johnson, D., Perkins, C., and J. Arkko, “Mobility Support in IPv6,” June 2004.) [RFC3775], the Mobile Node (MN) and the Home Agent (HA) use some IPsec Security Associations (SAs) in tunnel mode to protect some mobility signaling messages, mobile prefix discovery and optionally payload traffic. Since the MN may change its attachment point to the Internet, it is necessary for it to update the tunnel endpoint address of its IPsec SAs. This indicates that corresponding entries in IPsec databases (Security Policy (SPD) and SA (SAD) databases) should be updated when MN performs movements.
In a Mobile IPv6 environment, a key manager also needs to be notified when the SPD and SAD are updated. More generally, it needs to be provided with updated addresses for already negotiated and future IKE_SA. Because of its role and unlike common applications, key managers have to take part to the mobility process they secure: they need to be aware of address changes.
This document describes the need for an interface between Mobile IPv6 and IPsec/IKE and shows how the two protocols can interwork. An extension to the PF_KEY framework (McDonald, D., Metz, C., and B. Phan, “PF_KEY Key Management API, Version 2,” July 1998.) [RFC2367] which allows smooth and solid operation of IKE in a Mobile IPv6 environment is defined in the document. The extension is called PF_KEY MIGRATE and serves as a carrier for the necessary information for both the in-kernel IPsec stack and the key managers.
For the IPsec stack, this allows migrating the endpoint addresses of the IPsec SAs (and associated SP). For the key managers, this allows the mirrored structures to be updated (SAD and SPD). This also allows the addresses of already negotiated and associated IKE_SA to be migrated, and to make specific addresses available for negotiations of future IKE_SA. This set of operations performed by the KM on its internal structures is initiated by the MIPv6 process.
With the extension, the bootstrapping of the MN appears as a common operation for IKE, by having the right addresses needed for the negotiation available prior to the reception of the ACQUIRE message.
The extension is helpful for assuring smooth interworking between Mobile IPv6 and IPsec/IKE and achieving performance optimization.
As stated in the abstract, this document is heavily based on the content of a previous draft MIGRATE (Sugimoto, S., Nakamura, M., and F. Dupont, “PF_KEY Extension as an Interface between Mobile IPv6 and IPsec/IKE,” December 2007.) [MIGRATE]. This expired memo served as the basis for this work both from technical and editorial standpoints. Numerous technical discussions with some of its authors took place while working on this memo.
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In this document, the term IKE implicitly stands for both IKEv1 [RFC2409] (Harkins, D. and D. Carrel, “The Internet Key Exchange (IKE),” November 1998.) and IKEv2 [RFC4306] (Kaufman, C., “Internet Key Exchange (IKEv2) Protocol,” December 2005.). IKEv2 terminology is used preferentially when describing actions performed by the key manager but they also apply to the IKEv1 counterparts. For instance, when actions occur on IKE_SA, they also apply to Phase 1 for IKEv1, except otherwise specified. Key manager is used as a more generic term in the memo to refer to the IKE daemon.
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The section 4.4 of RFC 3776 (Arkko, J., Devarapalli, V., and F. Dupont, “Using IPsec to Protect Mobile IPv6 Signaling Between Mobile Nodes and Home Agents,” June 2004.) [RFC3776] specifies the rules which apply to IKE for MNs and HAs. The first requirement is to run IKE over the Care-of Address (CoA) because the Home Address (HoA) is usable only after the home registration but not yet in the bootstrapping phase, when Transport mode IPsec SA are commonly negotiated to protect BU/BA.
A tunnel IPsec SA pair protects some signaling messages and optionally all the traffic between the MN and HA. The initial SPD entry uses the HoA for the MN endpoint address and updates this address to the new CoA at each movement. A tunnel SA pair is created on demand and is updated too. The RFC 3775 (Johnson, D., Perkins, C., and J. Arkko, “Mobility Support in IPv6,” June 2004.) [RFC3775] assumes there is an API which performs the update in the SPD and SAD on both the MN and HA, and notify the IKE daemon. This document is mainly about this API.
Mobile IPv6 may need to make an access to the SPD not only for updating an endpoint address but also for deleting/inserting a specific SPD entry. When the MN performs Foreign-to-Home movement, IPsec SAs established between the MN and HA should be deleted, which means that the SPD entry should have no effect anymore. On the other hand, when the MN performs Home-to-Foreign movement, the IPsec SAs should be restored. Hence security policy entries that are associated with tunnel mode SAs may dynamically be added/removed (enabled/disabled) in along with MN's movements.
It should be noted that NEMO Basic Support (Devarapalli, V., Wakikawa, R., Petrescu, A., and P. Thubert, “Network Mobility (NEMO) Basic Support Protocol,” January 2005.) [RFC3963] has similar requirements for the Mobile Router (MR) and MR's HA (MRHA). In NEMO, the MR works just like a MN registering its location information to the MRHA and establishes a tunnel (IP-in-IP or IPsec tunnel). When an IPsec tunnel is established between MR and MRHA, the MR serves as a Security Gateway for the nodes connected to the mobile network. The MR is responsible for handling its tunnel endpoint properly.
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Despite the need for an interface between Mobile IPv6 and
IPsec/IKE, it should be kept simple. Following are the
requirements for the interface from a software engineering point
of view.
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In order to fulfill the needs and requirements described in Section 3 (Needs for Interactions between Mobile IPv6 and IPsec/IKE) and Section 4 (Requirements) we propose to extend the PF_KEY framework so that Mobile IPv6 and IPsec/IKE can interact with each other. The new message dedicated to that function is called MIGRATE. A new simple PF_KEY structure (sadb_x_kmaddress) is also defined to be used by MIGRATE to serve the purpose of IKE_SA update.
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The MIGRATE message is used for providing updated information to its two targets, the kernel IPsec stack and the key manager (when used). The figure below illustrates how Mobile IPv6 and IPsec/IKE components interact with each other using PF_KEY MIGRATE message in a dynamic keying scenario. On left top is a Mobile IPv6 entity (it may be possible that Mobile IPv6 component is completely implemented inside the kernel). In any case, Mobile IPv6 should be the one which issues the MIGRATE message. On right top is an IKE daemon which is responsible for establishing SAs required for Mobile IPv6 operation. In a manual keying scenario, the difference is mainly that there is no IKE daemon running on the system.
+-------------+ +------------+
| | | |
| Mobile IPv6 | | IKE Daemon |
| | | |
+-------------+ +------------+
| 1. PF_KEY A 4. Update SPD & SAD
| MIGRATE | 5. Update IKE_SA
+-----------+ +-----------+
| |
Userland V |
==========================[PF_KEY Socket]========================
Kernel | |
+----------+ +----------+
| 2. Update | 3. Update
V SPD V SAD
+-----------+ +------------+
| | | |
| SPD | | SAD |
| | | |
+-----------+ +------------+
In the kernel, the primary role of PF_KEY MIGRATE message is to migrate endpoint addresses of SA pairs, which results in requesting IPsec to update its databases (SPD and SAD). Even if tunnel mode is the primary target for MIPv6, MIGRATE is not limited to that mode (See Section 5.4 (Applicability of PF_KEY MIGRATE to Other Systems)). Then, after proper processing by the kernel, the MIGRATE message is sent to all open sockets. A listening key manager processes it, which results in a possible update of its internal structures. The specific actions are introduced on the following figure.
MIPv6 ---------------- kernel -------------------> IKE
process
1) update of SP 1) Update of SA and SP
endpoints and endpoints (in image)
associated SA. 2) Update of src and dst
@ in SPD image for
future SA negotiation
3) Update of IKE_SA src
and dst @ associated
with provided SA
In more details, the processing of a MIGRATE message is
done in following steps:
Note that the way IKE maintains its local copy of SPD (the SPD image) is an implementation specific issue since there is no standard interface to access SPD. Some IKE implementations may continuously monitor the SPD inside the kernel. Some IKE implementation may expect notifications from the kernel when the SPD is modified. In either way, the proposed mechanism gives a chance for IKE to keep its SPD image up-to-date which is significant in Mobile IPv6 operation.
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In the bootstrapping stage of Mobile IPv6, the MN and the HA need to establish IPsec SA to protect signaling messages of Mobile IPv6 such as BU and BA. When IKE is used to establish and maintain the SA pairs, the IKE negotiation is the very first transaction made between the MN and the HA.
As mentioned in [RFC3776] (Arkko, J., Devarapalli, V., and F. Dupont, “Using IPsec to Protect Mobile IPv6 Signaling Between Mobile Nodes and Home Agents,” June 2004.), some care is needed for the address management of the IKE negotiation in Mobile IPv6 environments. In particular, IKE negotiation to be made to establish a transport mode IPsec SA pair is tricky because the local IKE_SA address and the SA endpoint on the MN side (the Home Address) are different. This is because the home address cannot be used prior to the initial home registration. Even if the SADB_X_EXT_KMADDRESS extension defined in this memo enables the MIPv6 module to notify the IKE module about the IKE endpoint, address selection is left outside the scope of the document. In practice, a suitable candidate for the IKE endpoint is the primary CoA.
A simple solution to have the key manager be aware that a different address must be used for the negotiation of SA is to have it record this address within its mirrored SPD entries as soon as it becomes available. With that information, it is able to inflect its usual processing where it selects by default the source address of the SA for the negotiation (i.e. as local address of the IKE_SA). By having the MIGRATE message emitted by the Mobile IPv6 process before the emission of the BU, the address is already available to the key manager when the ACQUIRE message is received.
Even if the bootstrapping process initially appears differently than the usual process, having the internal structure of the key manager explicitly record the address (to be used for the negotiation of the SA for a specific SP) allows to keep things simple. The only requirement is that the MIGRATE message be emitted by the Mobile IPv6 process before it sends its Binding Update.
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Next, we will see how migration takes place in along with home registration. The figure below shows sequence of mobility signaling and PF_KEY MIGRATE messages while the MN roams around links. It is assumed that in the initial state the tunnel endpoint address for a given MN is set as its home address. In the initial home registration, the MN and HA migrate the tunnel endpoint address from the HoA to CoA1. It should be noted that no migration takes place when the MN performs re-registration since the care-of address remains the same. Accordingly, the MN performs movement and changes its primary care-of address from CoA1 to CoA2. A PF_KEY MIGRATE message is issued on both MN and HA for each direction. When the MN returns to home, migration takes place updating the endpoint address with the MN's home address.
With regard to the timing of issuing the MIGRATE message on the MN side during a handover, it must occur immediately before the emission of the binding update performing the home registration (as for bootstrapping). It is possible that ESP-protected (IPsec tunneled) user traffic be sent from the new CoA which is not known to the HA yet. As the HA processes the packets under IPsec, and as far as it finds a valid SA, then those packets will be authenticated regardless of their source IP address. In the end, there is no security issue in updating the IPsec SA endpoint while sending the BU and no reason not to do it. Furthermore, this may help the MN to minimize the packet loss of its outbound traffic during the handover.
MN HA
| |
~ ~
Movement->|
MIGRATE ->| BU (Initial home registration) |
(HoA->CoA1)|----------------------------------------->|
| BA |<- MIGRATE
|<-----------------------------------------| (HoA->CoA1)
| |
~ BU (Home re-registration) ~
|----------------------------------------->|
| BA |
|<-----------------------------------------|
| |
~ ~
| |
Movement->| BU (Home registration) |
MIGRATE ->| BA |
(CoA1->CoA2)|----------------------------------------->|
| |<- MIGRATE
|<-----------------------------------------| (CoA1->CoA2)
| |
~ ~
Movement->| BU (Home de-registration) |
MIGRATE ->| BA |
(CoA2->HoA)|----------------------------------------->|
| |<- MIGRATE
|<-----------------------------------------| (CoA2->HoA)
| |
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The bootstrapping process described in Section 5.1.2 (Bootstrapping) allows the creation of the SA by having the right source address available to the key manager before the beginning of the negotiation. When the SA has been negotiated, some further exchanges are expected to happen during the lifetime of the SA, including rekeying related exchanges. After the first movement (and obviously further ones), the address used during the bootstrapping process becomes invalid. Even if the SPD and SAD entries are updated (as described in Section 5.1.1 (System Overview)), there is also a need for the key manager to update the addresses used by the IKE_SA.
When the key manager processes the MIGRATE message, it uses the local and remote address information provided by the sadb_x_kmaddress structure to update:
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The Mobile IPv6 entity (MN or HA) code triggers the migration by sending a PF_KEY MIGRATE message to its PF_KEY socket. Conceptually, the PF_KEY MIGRATE message should contain following information:
o Key manager address information \
* source address | For IKE only
* destination address /
o Selector information: \
* source address/port |
* destination address/port |
* upper layer protocol (i.e., Mobility Header) |
* direction (inbound/outbound) |
o Old SA information: |
* old source endpoint address | For IKE and
* old destination endpoint address | IPsec stack
* IPsec protocol (ESP/AH) |
* mode (Tunnel/Transport/BEET) |
o New SA information: |
* new source endpoint address |
* new destination endpoint address |
* IPsec protocol (ESP/AH) |
* mode (Tunnel/Transport/BEET) /
Key manager address information content (source and destination address) is recorded in the associated entry of the SPD image. Those are used from now on by the key manager for SA negotiation associated with that SP. The information is also used by the key manager to update the local and remote addresses of the IKE_SA (used by already negotiated SA associated with the SP).
Selector information is required for specifying the target SPD entry to be updated. Basically the information should contain necessary elements which characterize traffic selector as specified in the IPsec architecture ([RFC2401] (Kent, S. and R. Atkinson, “Security Architecture for the Internet Protocol,” November 1998.), [RFC4301] (Kent, S. and K. Seo, “Security Architecture for the Internet Protocol,” December 2005.)). With regard to the upper layer protocol, when the Mobile IPv6 stack is not fully aware of IPsec configuration, a wildcard value could be given. In such case, an upper layer protocol information should not be taken into account for searching SPD entry. Plus, the direction of the security policy (inbound/outbound) should be provided.
The old SA information, along with old locator information is used to specify target SA to be updated. For tunnel and BEET [I‑D.nikander‑esp‑beet‑mode] (Melen, J. and P. Nikander, “A Bound End-to-End Tunnel (BEET) mode for ESP,” August 2008.) modes, the endpoint addresses refer to the source and destination IP addresses that appear in the IP header, and those should be provided by the MIGRATE message. For transport mode, we require it to be present to keep a fixed message format. For all modes, the address information represents the locators of the SA. For transport mode, it must match with the addresses provided in the selector. For tunnel mode, it is obviously not required.
The source and destination addresses (locators) of the target entry should be overwritten. New locator values should also be used to update SP. Note that the IPsec protocol and mode fields should not be updated by a PF_KEY MIGRATE message.
A PF_KEY MIGRATE message should be formed, based on security policy configuration and binding record. The selector information and some parts of the SA information (IPsec protocol and mode) should be taken from the policy configuration. The rest of the information should be taken from the sequential binding information. For example, in the case where the MN updates its inbound security policy and corresponding tunnel mode SA pair, the old source address should be set as its previous CoA, and the new source address should be set as its current CoA. Hence, the MN should sequentially keep track of its CoA record. Such information shall be stored in binding update list entry. For the same reason, the HA should keep track of previous CoAs of MNs. Such information shall be stored in binding cache entry. In previous scenario, the source and destination entries of the address information for the key manager should respectively be set to the CoA and the address of the HA.
A detailed format of MIGRATE message is provided in Appendix A.
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Since a PF_KEY MIGRATE message is applied to a single SPD entry, the kernel should first check validity of the message. During that process, it simply skips sadb_x_kmaddress structure content. If the message is invalid, an EINVAL error MUST be returned as a return value for the write() operation made to the PF_KEY socket. After the validation, the kernel checks if the target SPD entry really exists. If no entry is found, an ENOENT error MUST be returned. If a SPD entry is found and successfully updated, a success (0) MUST be returned regardless of subsequent result of SAD lookup/update. Note that there may be cases where a corresponding SAD entry does not exist even if a SPD entry is successfully updated. In any error case, a PF_KEY MIGRATE message MUST NOT have any effect on the SPD and SAD.
With respect to the behavior of a normal process (including the IKE daemon) which receives a PF_KEY MIGRATE message from a PF_KEY socket, it SHOULD first check if the message does not include erroneous information. When there is any error indicated, the process MUST silently discard the PF_KEY MIGRATE message. Otherwise, the processing of the message may continue. This implies that the kernel is the only entity responsible for returning a status regarding message validation.
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The PF_KEY MIGRATE extension can also be applied to other systems than Mobile IPv6. In some systems, there is a need to update endpoint address of IPsec security association for various reasons such as mobility management and multihoming.
In a Mobile VPN scenario (aka "road warrior"), client node roams around different IP subnets while maintaining security associations with the security gateway. Just like in Mobile IPv6 case, both of the IKE peers need to update the endpoint of the IPsec tunnel and PF_KEY MIGRATE message can be used for that purpose.
In HIP mobility management scenario [RFC5206] (Nikander, P., Henderson, T., Vogt, C., and J. Arkko, “End-Host Mobility and Multihoming with the Host Identity Protocol,” April 2008.), a mobile host can maintain a HIP association with its peer while moving around IP subnets. When the mobile host changes its attachment point to the Internet, it sends an UPDATE message to the peer reporting its new locator. Since HIP association is represented by an IPsec security association of ESP BEET mode, the same mechanism can be applied for the purpose of updating endpoint. The procedure of MIGRATE can take place when the mobile host detects movement and when the peer receives the UPDATE message.
From the ID/Locator separation point of view, PF_KEY MIGRATE is designed to update locators stored in an IPsec security association. Even if this usually applies to IPsec security associations in tunnel mode, the MIGRATE framework also covers the transport mode. For instance, there are exceptional cases where IPsec security associations are bundled. In some case, a transport mode security association may be bundled with a tunnel mode security association. For instance, a combination of AH (transport mode) and ESP (tunnel mode) may assure confidentiality of the payload as well as data integritiy of the whole IP packet including outer header. In such case, PF_KEY MIGRATE message may be used for updating endpoint addresses of IPsec transport mode.
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Dual Stack Mobile IPv6 [I‑D.ietf‑mext‑nemo‑v4traversal] (Soliman, H., “Mobile IPv6 support for dual stack Hosts and Routers (DSMIPv6),” July 2008.) supports a scenario where a MN is connected to a network behind a Network Address Translator (NAT). In such case, the MN assigns a IPv4 private address to its network interface but it is still capable of registering its care-of address to the HA, using the NAT Traversal technique [RFC3948] (Huttunen, A., Swander, B., Volpe, V., DiBurro, L., and M. Stenberg, “UDP Encapsulation of IPsec ESP Packets,” January 2005.). The MN and HA leverage an IPsec tunnel to protect the return routability messages.
It is possible for the PF_KEY MIGRATE message to handle IPv4 private address when the MN is behind a NAT device. In a NAT Traversal case, the endpoint address of the MN is characterized by the IP address and the pair of source and destination port numbers used for the UDP encapsulation. Therefore, in a NAT Traversal scenario, a Mobile IPv6 module MUST issue a PF_KEY MIGRATE message along with the pair of source and destination port numbers of a UDP encpasulation, to handle IPv4 private address.
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Currently, a Security Parameter Index (SPI) is not included in the old SA information to specify target SAD entry. This helps to lessen operational burden of Mobile IPv6. However, this simplification can produce ambiguity in searching for the target security association entry. When the unique SPD level is available, it should be used because it avoids this problem both by marking the SAs to update and by limiting SA sharing.
It should be noted that delivery of PF_KEY MIGRATE messages cannot be guaranteed, which is common to other PF_KEY messages. It may be possible (even if highly unlikely) that a MIGRATE message be lost. In such case, there will be inconsistency between the binding record managed by Mobile IPv6 and IPsec database inside the kernel or the IKE daemon. Once a PF_KEY MIGRATE message is lost, it would not be possible for the receiver to process some subsequent MIGRATE messages properly. Reinitialization of the Mobile IPv6 stack and IPsec databases may be needed for recovery.
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In order to realize the proposed mechanism, there are some
necessary modifications to Mobile IPv6 and IPsec/IKE. They are
listed below for implementors of Mobile IPv6 and/or
IPsec/IKE.
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There is no specific security considerations for the mechanisms introduced by the document but as it makes deployment of dynamic keying in Mobile IPv6 environments easier it should improve the security of such environments. Note that dynamic keying is known to be more secure (it provides anti-replay for instance) and far more scalable.
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| [RFC2367] | McDonald, D., Metz, C., and B. Phan, “PF_KEY Key Management API, Version 2,” RFC 2367, July 1998 (TXT). |
| [RFC2401] | Kent, S. and R. Atkinson, “Security Architecture for the Internet Protocol,” RFC 2401, November 1998 (TXT). |
| [RFC2409] | Harkins, D. and D. Carrel, “The Internet Key Exchange (IKE),” RFC 2409, November 1998 (TXT). |
| [RFC3775] | Johnson, D., Perkins, C., and J. Arkko, “Mobility Support in IPv6,” RFC 3775, June 2004 (TXT). |
| [RFC3776] | Arkko, J., Devarapalli, V., and F. Dupont, “Using IPsec to Protect Mobile IPv6 Signaling Between Mobile Nodes and Home Agents,” RFC 3776, June 2004 (TXT). |
| [RFC4301] | Kent, S. and K. Seo, “Security Architecture for the Internet Protocol,” RFC 4301, December 2005 (TXT). |
| [RFC4306] | Kaufman, C., “Internet Key Exchange (IKEv2) Protocol,” RFC 4306, December 2005 (TXT). |
| TOC |
| [I-D.ietf-mext-nemo-v4traversal] | Soliman, H., “Mobile IPv6 support for dual stack Hosts and Routers (DSMIPv6),” draft-ietf-mext-nemo-v4traversal-05 (work in progress), July 2008 (TXT). |
| [I-D.nikander-esp-beet-mode] | Melen, J. and P. Nikander, “A Bound End-to-End Tunnel (BEET) mode for ESP,” draft-nikander-esp-beet-mode-09 (work in progress), August 2008 (TXT). |
| [MIGRATE] | Sugimoto, S., Nakamura, M., and F. Dupont, “PF_KEY Extension as an Interface between Mobile IPv6 and IPsec/IKE,” draft-sugimoto-mip6-pfkey-migrate-04 (work in progress), December 2007 (TXT). |
| [RFC3948] | Huttunen, A., Swander, B., Volpe, V., DiBurro, L., and M. Stenberg, “UDP Encapsulation of IPsec ESP Packets,” RFC 3948, January 2005 (TXT). |
| [RFC3963] | Devarapalli, V., Wakikawa, R., Petrescu, A., and P. Thubert, “Network Mobility (NEMO) Basic Support Protocol,” RFC 3963, January 2005 (TXT). |
| [RFC5206] | Nikander, P., Henderson, T., Vogt, C., and J. Arkko, “End-Host Mobility and Multihoming with the Host Identity Protocol,” RFC 5206, April 2008 (TXT). |
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The figure below shows the message format of PF_KEY MIGRATE. The message consists of 7 parts (boundary of each part is marked with ">"). The message starts with PF_KEY base message header directly followed by a sadb_x_kmaddress{} structure. The extension holds the two IKE_SA local and remote addresses as opaque data for the key manager (two 64-bit aligned sockaddr). It is then followed by two address extensions: those respectively hold source and destination addresses of the selector. The rest of the message is specific to IPsec implementations on BSD and Linux. sadb_x_policy{} structure holds additional information of security policy. The last part of the message is a pair of sadb_x_ipsecrequest{} structures that hold old and new SA information.
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 +---------------+---------------+---------------+---------------+ | ...version | sadb_msg_type | sadb_msg_errno| ...msg_satype | +---------------+---------------+---------------+---------------+ | sadb_msg_len | sadb_msg_reserved | +---------------+---------------+---------------+---------------+ | sadb_msg_seq | +---------------+---------------+---------------+---------------+ | sadb_msg_pid | >+---------------+---------------+---------------+---------------+ | sadb_x_kmaddress_len | sadb_x_kmaddress_exttype | +---------------+---------------+---------------+---------------+ | sadb_x_kmaddress_reserved | +---------------+---------------+---------------+---------------+ ~ IKE_SA local address (64-bit aligned ... ~ +---------------+---------------+---------------+---------------+ ~ IKE_SA remote address ... pair of sockaddr) ~ >+---------------+---------------+---------------+---------------+ | sadb_address_len | sadb_address_exttype | +---------------+---------------+---------------+---------------+ | _address_proto| ..._prefixlen | sadb_address_reserved | +---------------+---------------+---------------+---------------+ ~ selector source address (64-bit aligned sockaddr) ~ >+---------------+---------------+---------------+---------------+ | sadb_address_len | sadb_address_exttype | +---------------+---------------+---------------+---------------+ | _address_proto| ..._prefixlen | sadb_address_reserved | +---------------+---------------+---------------+---------------+ ~ selector destination address (64-bit aligned sockaddr) ~ >+---------------+---------------+---------------+---------------+ | sadb_x_policy_len | sadb_x_policy_exttype | +---------------+---------------+---------------+---------------+ | sadb_x_policy_type | ..._dir | ..._reserved | +---------------+---------------+---------------+---------------+ | sadb_x_policy_id | +---------------+---------------+---------------+---------------+ | sadb_x_policy_priority | >+---------------+---------------+---------------+---------------+ | sadb_x_ipsecrequest_len | sadb_x_ipsecrequest_proto | +---------------+---------------+---------------+---------------+ | ..._mode | ..._level | sadb_x_ipsecrequest_reserved1 | +---------------+---------------+---------------+---------------+ | sadb_x_ipsecrequest_reqid | +---------------+---------------+---------------+---------------+ | sadb_x_ipsecrequest_reserved2 | +---------------+---------------+---------------+---------------+ ~ old source endpoint address (64-bit aligned ... ~ +---------------+---------------+---------------+---------------+ ~ old destination endpoint address ... pair of sockaddr) ~ >+---------------+---------------+---------------+---------------+ | sadb_x_ipsecrequest_len | sadb_x_ipsecrequest_proto | +---------------+---------------+---------------+---------------+ | ..._mode | ..._level | sadb_x_ipsecrequest_reserved1 | +---------------+---------------+---------------+---------------+ | sadb_x_ipsecrequest_reqid | +---------------+---------------+---------------+---------------+ | sadb_x_ipsecrequest_reserved2 | +---------------+---------------+---------------+---------------+ ~ new source endpoint address (64-bit aligned ... ~ +---------------+---------------+---------------+---------------+ ~ new destination endpoint address ... pair of sockaddr) ~ +---------------+---------------+---------------+---------------+
Following is a structure of PF_KEY base message header specified in [RFC2367] (McDonald, D., Metz, C., and B. Phan, “PF_KEY Key Management API, Version 2,” July 1998.). A new message type for PF_KEY MIGRATE (i.e., SADB_X_MIGRATE) should be specified in member sadb_msg_type.
struct sadb_msg {
uint8_t sadb_msg_version;
uint8_t sadb_msg_type;
uint8_t sadb_msg_errno;
uint8_t sadb_msg_satype;
uint16_t sadb_msg_len;
uint16_t sadb_msg_reserved;
uint32_t sadb_msg_seq;
uint32_t sadb_msg_pid;
};
Following is the structure of key manager address extension header. SADB_X_EXT_KMADDRESS should be specified in sadb_x_kmaddress_exttype field. It is followed by a pair of sockaddr structures holding respectively up-to-date local and remote address to be used by IKE_SA. The pair is globally 64-bit aligned.
struct sadb_x_kmaddress {
uint16_t sadb_x_kmaddress_len;
uint16_t sadb_x_kmaddress_exttype;
uint32_t sadb_x_kmaddress_reserved;
};
/* sizeof(struct sadb_x_kmaddress) == 8 */
/* Followed by two sockaddr (local and remote) */
Following is a structure of address extension header specified in [RFC2367] (McDonald, D., Metz, C., and B. Phan, “PF_KEY Key Management API, Version 2,” July 1998.). Upper layer protocol should be specified in member sadb_address_proto.
struct sadb_address {
uint16_t sadb_address_len;
uint16_t sadb_address_exttype;
uint8_t sadb_address_proto;
uint8_t sadb_address_prefixlen;
uint16_t sadb_address_reserved;
};
Following is a structure for holding attributes that are relevant to security policy, which is available on BSD and Linux IPsec implementations. Direction of the target security policy should be specified in member sadb_x_policy_dir.
struct sadb_x_policy {
uint16_t sadb_x_policy_len;
uint16_t sadb_x_policy_exttype;
uint16_t sadb_x_policy_type;
uint8_t sadb_x_policy_dir;
uint8_t sadb_x_policy_reserved;
uint32_t sadb_x_policy_id;
uint32_t sadb_x_policy_priority;
};
Following is a structure for holding attributes that are relevant to security association, which is available on BSD and Linux IPsec implementation. IPsec protocol (ESP or AH) and mode of the target security association should be provided in member sadb_x_ipsecrequest_proto and sadb_x_ipsecrequest_mode, respectively.
struct sadb_x_ipsecrequest {
uint16_t sadb_x_ipsecrequest_len;
uint16_t sadb_x_ipsecrequest_proto;
uint8_t sadb_x_ipsecrequest_mode;
uint8_t sadb_x_ipsecrequest_level;
uint16_t sadb_x_ipsecrequest_reserved1;
uint32_t sadb_x_ipsecrequest_reqid;
uint32_t sadb_x_ipsecrequest_reserved2;
};
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Various people had contributed and were acknowledged in previous version of MIGRATE draft. Because most of the text from previous draft has been kept in this document, those acknowledgements are still valid: Sebastien Decugis, Mitsuru Kanda, Kazunori Miyazawa, Tsuyoshi Momose Shoichi Sakane, Keiichi Shima, Noriaki Takamiya, and Hideaki Yoshifuji.
Support of NAT Traversal was suggested by Kazunori Miyazawa.
We would also like to acknowledge here the positive technical feedback from Shinta Sugimoto while extending his MIGRATE mechanism and also the work provided by people of USAGI (Masahide Nakamura, Shinta Sugimoto, Hideaki Yoshifuji, ...) on Linux kernel's Mobile IPv6 and IPsec stack.
This document was generated by xml2rfc.
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| Arnaud Ebalard | |
| EADS Innovation Works | |
| 12, rue Pasteur - BP76 | |
| Suresnes 92152 | |
| France | |
| Phone: | +33 1 46 97 30 28 |
| Email: | arnaud.ebalard@eads.net |
| Sebastien Decugis | |
| National Institute of Information and Communications Technology | |
| 4-2-1, Nukui-Kitamachi, | |
| Koganei, Tokyo 184-8795 | |
| Japan | |
| Email: | sdecugis@hongo.wide.ad.jp |
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