Network Working Group S. Sugimoto
Internet-Draft Ericsson
Expires: March 23, 2007 F. Dupont
CELAR
M. Nakamura
Hitachi
September 19, 2006
PF_KEY Extension as an Interface between Mobile IPv6 and IPsec/IKE
draft-sugimoto-mip6-pfkey-migrate-03
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Copyright Notice
Copyright (C) The Internet Society (2006).
Abstract
This document describes the need for an interface between Mobile IPv6
and IPsec/IKE and show how the two protocols can interwork. We
propose a set of extensions to the PF_KEY framework which allows
smooth and solid operation of IKE in a Mobile IPv6 environment. The
first extension is called PF_KEY MIGRATE and is for migrating the
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endpoint addresses of a IPsec Security Association pair in tunnel
mode. The second extension is named SADB_X_EXT_PACKET and allows IKE
to make the right choice for address selection in bootstrapping
process. Both extensions are helpful for assuring smooth
interworking between Mobile IPv6 and IPsec/IKE and achieving
performance optimization.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Needs for Interactions between Mobile IPv6 and IPsec/IKE . . . 3
3. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. PF_KEY Extensions for Mobile IPv6 . . . . . . . . . . . . . . 4
4.1. PF_KEY MIGRATE Message . . . . . . . . . . . . . . . . . . 5
4.1.1. Overview . . . . . . . . . . . . . . . . . . . . . . . 5
4.1.2. Message Sequence . . . . . . . . . . . . . . . . . . . 6
4.1.3. Issuing PF_KEY MIGRATE Message . . . . . . . . . . . . 7
4.1.4. Processing PF_KEY MIGRATE Message . . . . . . . . . . 8
4.1.5. Applicability of PF_KEY MIGRATE to Other Systems . . . 9
4.1.6. Limitation of PF_KEY MIGRATE . . . . . . . . . . . . . 9
4.2. PF_KEY Packet Extension . . . . . . . . . . . . . . . . . 10
4.2.1. Inserting Packet Extension to SADB_ACQUIRE Message . . 10
4.2.2. Processing SADB_ACQUIRE Message with Packet
Extension . . . . . . . . . . . . . . . . . . . . . . 11
4.2.3. Relation of Packet Extension to IKEv2 . . . . . . . . 11
5. Necessary Modifications to Mobile IPv6 and IPsec/IKE . . . . . 12
6. Security Considerations . . . . . . . . . . . . . . . . . . . 12
7. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . 13
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Appendix A. PF_KEY MIGRATE Message Format . . . . . . . . . . . . 14
Appendix B. Acknowledgements . . . . . . . . . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 17
Intellectual Property and Copyright Statements . . . . . . . . . . 18
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1. Introduction
In Mobile IPv6 [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 to update its endpoint address
of the IPsec SAs. This indicates that corresponding entry in IPsec
databases (Security Policy (SPD) and SA (SAD) databases) should be
updated when MN performs movements. In addition, IKE requires
treatment to keep its IKE session alive in a Mobile IPv6 environment.
This document describes the need for an interface between Mobile IPv6
and IPsec/IKE and shows how the two protocols can interwork. We
propose a set of extensions to the PF_KEY framework [RFC2367] which
allows smooth and solid operation of IKE in an Mobile IPv6
environment. The first extension is called PF_KEY MIGRATE and is for
migrating the endpoint addresses of the IPsec SAs in tunnel mode.
The second extension is named SADB_X_EXT_PACKET and allows IKE to
make the right choice in address selection in the bootstrapping
process. Both extensions are helpful for assuring smooth
interworking between Mobile IPv6 and IPsec/IKE and achieving
performance optimization.
In this document, the term IKE implicitly stands for both IKEv1
[RFC2409] and IKEv2 [RFC4306]. In description with regard to any
functionality that is specific to either of the protocols, specific
protocol name shall be provided.
2. Needs for Interactions between Mobile IPv6 and IPsec/IKE
The section 4.4 of RFC 3776 [RFC3776] specifies the rules which
applies 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 so not yet in the
bootstrapping phase.
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 [RFC3775] assumes there
is an API which performs the update in the SPD and SAD on both the MN
and HA. This document is mainly about this API.
Mobile IPv6 specifies a flag named Key Management Mobility Capability
bit (K-bit) in Binding Update (BU) and Binding Acknowledgement (BA)
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messages (section 10.3.1 of [RFC3775]), which indicates the ability
of IKE sessions to survive movement. When both the MN and HA agree
to use this functionality, the IKE daemons dynamically update the IKE
session when the MN moves. In order to realize this, IKE daemons
should be notified by Mobile IPv6, and necessary information to
migrate the IKE session should be provided.
Mobile IPv6 may need to make an access to the SPD not only for
updating an endpoint address but also for the deletion/insertion of 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 any more. 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 [RFC3963] has similar
requirements for the Mobile Router (MR) and MR's HA (MRHA). In NEMO,
the MR works just as same as 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.
3. Requirements
Given the need for an interface between Mobile IPv6 and IPsec/IKE,
there should be a minimum interface between the two protocols.
Followings are the requirements for the interface from a software
engineering point of view.
o Necessary modifications to the existing software, namely Mobile
IPv6 and IPsec/IKE, in order to realize proposed mechanisms,
should be kept minimum.
o Proposed mechanism should not be platform dependent. The
mechanism should be based on technology which is commonly
available on various platform. This seems to be essential for
achieving high portability of the implementation which supports
proposed mechanisms.
4. PF_KEY Extensions for Mobile IPv6
In order to fulfill the needs and requirements described in Section 2
and Section 3 we propose to extend the PF_KEY framework so that
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Mobile IPv6 and IPsec/IKE could interact with each other.
4.1. PF_KEY MIGRATE Message
The first extension is primarily for migrating an endpoint address of
an IPsec SA pair in tunnel mode from one to another, which results in
updating IPsec databases. A new PF_KEY message named MIGRATE is
introduced for the mechanism.
4.1.1. Overview
The figure below illustrates how Mobile IPv6 and IPsec/IKE components
interact with each other using PF_KEY MIGRATE messages in a dynamic
keying scenario. On left top, there is a Mobile IPv6 entity. It may
be possible that Mobile IPv6 component is completely implemented
inside the kernel (this is the case for our implementations because
it makes some facilities and extensions far easier at the cost of
maintaining a SPD image in daemons). In any case, Mobile IPv6 should
be the one which issues the MIGRATE messages. On right top, there is
an IKE daemon which is responsible for establishing SAs required for
Mobile IPv6 operation. In a manual keying scenario, the difference
is only that there is no IKE daemon running on the system.
+-------------+ +------------+
| | | |
| Mobile IPv6 | | IKE Daemon |
| | | |
+-------------+ +------------+
| 1. PF_KEY A 4. Update
| MIGRATE | SPD & SAD
+-----------+ +-----------+
| |
Userland V |
==========================[PF_KEY Socket]========================
Kernel | |
+----------+ +----------+
| 2. Update | 3. Update
V SPD V SAD
+-----------+ +------------+
| | | |
| SPD | | SAD |
| | | |
+-----------+ +------------+
The primary role of PF_KEY MIGRATE messages is to migrate endpoint
addresses of tunnel mode SA pairs requesting IPsec to update its
databases (SPD and SAD). In addition, the new message can be used by
IKE to enhance its mobility capability. When a PF_KEY MIGRATE
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message is properly processed by the kernel, it is sent to all open
sockets as normal PF_KEY messages. The processing of a sequence of
MIGRATE messages is done in following steps:
o Mobile IPv6 issues a PF_KEY MIGRATE message to the PF_KEY socket.
o The operating system (kernel) validates the message and checks if
corresponding security policy entry exists in SPD.
o When the message is confirmed to be valid, the target SPD entry is
updated according to the MIGRATE message. If there is any target
SA found that are also target of the update, those should also be
updated.
o After the MIGRATE message is successfully processed inside the
kernel, it will be sent to all open PF_KEY sockets.
o The IKE daemon receives the MIGRATE message from its PF_KEY socket
and updates its SPD and SAD images. The IKE daemon may also
update its state to keep the IKE session alive.
Note that the way IKE maintains its local copy of SPD (the SPD image)
is implementation specific issue since there is no standard interface
to access SPD. Some IKE implementation may continuously monitor the
SPD inside the kernel. Some IKE implementation may expect
notification 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.
4.1.2. Message Sequence
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 a MIGRATE message on the MN
side, the message can be issued immediately after the home
registration. That is, there is no need to wait until the
acknowledgment from the HA to issue migrate the endpoint addresses
stored in the IPsec databases. The Mobile IPv6 specification
([RFC3775] Section 11.6.3) actually allows the MN to start using the
new care-of address immediately after sending a BU message to the HA.
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This may help the MN to minimize the packet loss of its outbound
traffic during the handover.
MN HA
| |
~ ~
Movement->| BU (Initial home registration) |
|----------------------------------------->|
MIGRATE ->| BA |<- MIGRATE
(HoA->CoA1) |<-----------------------------------------| (HoA->CoA1)
| |
~ BU (Home re-registration) ~
|----------------------------------------->|
| BA |
|<-----------------------------------------|
| |
~ ~
| |
Movement->| BU (Home registration) |
|----------------------------------------->|
MIGRATE ->| BA |<- MIGRATE
(CoA1->CoA2)|<-----------------------------------------| (CoA1->CoA2)
| |
~ ~
Movement->| BU (Home de-registration) |
|----------------------------------------->|
MIGRATE ->| BA |<- MIGRATE
(CoA2->HoA) |<-----------------------------------------| (CoA2->HoA)
| |
4.1.3. Issuing PF_KEY MIGRATE Message
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 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
* old destination endpoint address
* IPsec protocol (ESP/AH)
* mode (Tunnel)
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o New SA information:
* new source endpoint address
* new destination endpoint address
* IPsec protocol (ESP/AH)
* mode (Tunnel)
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], [RFC4301]). With regard to the upper
layer protocol, when the Mobile IPv6 stack is not fully aware of
IPsec configuration, an wild-card 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
is used to specify target security association to be updated. The
source and destination addresses of the target entry should be
overwritten with the ones included in the new SA information. 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.
Additionally, a piece of information which indicates a mobility
capability of IKE (K-bit) should be provided by any means. This
makes it possible for IKE to see if there is a need to update its
state (IKE endpoint addresses) in accordance with PF_KEY MIGRATE
messages.
A detailed message format of PF_KEY MIGRATE is provided in
Appendix A.
4.1.4. Processing PF_KEY MIGRATE Message
Since a PF_KEY MIGRATE message is applied to a single SPD entry, the
kernel should first check validity of the message. If the message is
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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 a
case 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.
4.1.5. Applicability of PF_KEY MIGRATE to Other Systems
It should be noted that the PF_KEY MIGRATE extension is also
applicable to other systems than Mobile IPv6 and/or IKE. For
example, it can be used in a scenario where an IPsec/IKE enabled node
establishes tunnel mode SAs association with its Security Gateway
while it roams around the network (aka "road warrior"). The security
policy is set as such that all traffic should bi-directionally go
through the tunnel IPsec SAs. In such case, the migration of a
tunnel endpoint address can be handled by PF_KEY MIGRATE messages.
Each time the node changes its attachment point to the Internet,
PF_KEY MIGRATE messages should be issued to the system.
Consequently, the IPsec databases (SPD and SAD) shall be properly
updated.
It is also essential to keep design of the mechanism protocol
independent. More specifically, the PF_KEY MIGRATE extension should
be able to work on both IPv4 and IPv6. In order to achieve this, the
IP addresses to be stored in selector and SA information should be
handled in a protocol-independent manner.
4.1.6. Limitation of PF_KEY MIGRATE
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 use
because it avoids this problem both by marking the SAs to update and
by limiting SA sharing.
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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 that a MIGRATE message is lost. In such case, there will be
inconsistency between the binding record managed by Mobile IPv6 and
IPsec database inside the kernel. 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.
4.2. PF_KEY Packet Extension
In the initial stage of MIPv6 operation known as the bootstrapping
process, the MN and HA probably need to establish SAs from scratch in
order to start the MIPv6 operation. If IKE is used to maintain the
SAs, the MN and HA are required to establish a transport mode SA pair
so that the MN could make the initial protected home registration to
the HA. As mentioned in RFC 3776 [RFC3776], the IKE negotiation
should be done carefully in terms of handling the identity of the MN.
More specifically, IKE must be run over the MN's primary CoA while
the SA pair should be based on the MN's HoA. Note that the HoA
cannot be used prior to the initial home registration. This is an
exceptional case of IKE negotiation in a sense that the peer address
(the address on which IKE runs) and the IP address to be used as
selector for the SAs are different. Since IKE should not be required
to maintain mobility state, there is a need to guide IKE to make the
right choice for address/identity.
A simple solution for this explicit notification can be provided by
extending PF_KEY framework by including information of the triggering
packet into SADB_ACQUIRE messages. This extension allows receiver of
a SADB_ACQUIRE message to determine which address to use for what
purpose, i.e., to recognize the exceptional case as all the needed
informations are already in the home registration binding update. As
shown below, a SADB_ACQUIRE message MAY contain an extension which
contains the triggering packet (the whole packet, information
extracted from it by the kernel or as we recommend enough of the
beginning of it).
<base, address(SD), address(P)*, identity(SD)*,
sensitivity*, proposal, packet*>
4.2.1. Inserting Packet Extension to SADB_ACQUIRE Message
The IPsec subsystem MAY include a Packet Extension to a SADB_ACQUIRE
message when it is triggered by an output of data packet. The Packet
Extension simply contains the information of the triggering packet.
Like any other extension headers specified in RFC 2367 [RFC2367], a
Packet Extension (SADB_X_EXT_PACKET) MUST follow the basic rules and
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be formulated in the type-length-value format. A redundant part of
the original IP packet (i.e., payload/trailer) MAY be eliminated.
More than one Packet Extension header MUST NOT be appended to the
message. A sadb_x_packet extension header is followed by an IP
packet which has triggered the SADB_ACQUIRE message. Note that the
Packet Extension is protocol independent, which means that the
triggering packet included in the extension header could be either
IPv4 or IPv6. The address family of the triggering packet can be
recognized by the first 4 bits of the IP packet.
struct sadb_x_packet {
uint16_t sadb_packet_len;
uint16_t sadb_packet_exttype;
};
/* sizeof(struct sadb_x_packet) == 4 */
/* followed by an IP packet header which triggered
the SADB_ACQUIRE message */
4.2.2. Processing SADB_ACQUIRE Message with Packet Extension
A receiver of a SADB_ACQUIRE message with a Packet Extension MAY
extract and process the extension header. A MIPv6-aware IKE daemon
should be able to process a Packet Extension which includes the IPv6
packet which carries an initial home registration BU message. Such
packet includes a home address destination option which contains the
primary CoA of the MN and the source address field of the IPv6 header
contains the HoA of the MN (note the exact layout depends on the
place of the IPsec acquiring code, we assume here its place follows
the section 11.3.2 of [RFC3775]). The destination address field of
the IPv6 header contains the address of the HA, the mobility header a
BU (type 5) for home registration (H flag set to one).
Receipt of SADB_ACQUIRE Message with Packet Extension containing BU
message implies that IKE is required to establish SAs for the MIPv6
home registration. Accordingly, the IKE should be able to make a
right choice of address selection. The CoA must be used as a peer
address in the IKE negotiation and the HoA should be used as selector
of transport mode SAs and as endpoint address of tunnel mode SAs.
4.2.3. Relation of Packet Extension to IKEv2
In IKEv2 [RFC4306], when the initiator has requested to establish SAs
triggered by a data packet, the first traffic selector of TSi and TSr
should reflect the triggering packet. Therefore, IKEv2 could take
advantage of Packet Extensions when some information from triggering
packets are needed for a traffic selector negotiation.
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5. Necessary Modifications to Mobile IPv6 and IPsec/IKE
In order to realize the proposed mechanism, there are some necessary
modifications to Mobile IPv6 and IPsec/IKE. Following are the
summary of necessary modifications, which could be of interest to
implementors of Mobile IPv6 and/or IPsec/IKE.
o Modifications to Mobile IPv6:
* The Mobile IPv6 code can make an access to PF_KEY socket. In
particular, the Mobile IPv6 code should have privilege to write
messages into a PF_KEY socket.
* Issuing PF_KEY MIGRATE messages: in order to send MIGRATE
messages, it is required that the Mobile IPv6 code has some
knowledge of its IPsec configuration and precise binding
record. The Mobile IPv6 code may be aware of exact IPsec
configuration in form or security policy. It would also be
possible that the Mobile IPv6 code is only aware of minimum
IPsec configuration whether if IPsec is utilized or not.
o Modifications to IPsec:
* Processing PF_KEY MIGRATE messages: the kernel should be able
to process PF_KEY MIGRATE messages sent by the Mobile IPv6
code. Unless the message is invalid, it should be sent to all
open PF_KEY sockets.
* Enabling Packet Extensions (SADB_X_EXT_PACKET): the kernel
should be able to append a SADB_X_EXT_PACKET extension to
SADB_MIGRATE messages when they are triggered by an output of a
data packet.
o Modifications to IKE:
* Processing PF_KEY MIGRATE messages: the IKE code may update its
local copy of IPsec databases (SPD and SAD) in accordance with
received PF_KEY MIGRATE messages. In addition, it may update
its state / IKE session with new endpoint addresses indicated
by PF_KEY MIGRATE messages.
* Processing of Packet Extensions (SADB_X_EXT_PACKET): the IKE
code may process SADB_X_EXT_PACKET extensions and extract
necessary information from triggering packets. In order for
the IKE code to be MIPv6-aware, it should properly extract the
home address, care-of address, and HA address from IP packets
which carry home registration BU messages.
6. Security Considerations
There is no specific security considerations for the mechanisms
introduced by the document but as it should make 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
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scalable.
7. Conclusion
o There is a need for Mobile IPv6 and IPsec/IKE to interact with
each other to provide full support of IPsec security functions.
o An extension to the PF_KEY framework (PF_KEY MIGRATE message) is
proposed, which makes it possible for the IPsec/IKE to migrate an
endpoint address of tunnel IPsec SAs from one to another.
o PF_KEY MIGRATE messages also make it possible for IKE to survive
movements by updating its IKE session.
o In order for the IKE to perform key negotiations and rekeying,
effort should be made to keep its SPD image up-to-date.
o The proposed mechanism was implemented on both Linux and BSD
platforms and confirmed to be working well.
o Currently, large portion of the proposed mechanism is
implementation dependent due to lack of standard interface to
access the SPD (PF_POLICY?).
8. References
[RFC2367] McDonald, D., Metz, C., and B. Phan, "PF_KEY Key
Management API, Version 2", RFC 2367, July 1998.
[RFC2401] Kent, S. and R. Atkinson, "Security Architecture for the
Internet Protocol", RFC 2401, November 1998.
[RFC2409] Harkins, D. and D. Carrel, "The Internet Key Exchange
(IKE)", RFC 2409, November 1998.
[RFC3775] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support
in IPv6", RFC 3775, June 2004.
[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.
[RFC3963] Devarapalli, V., Wakikawa, R., Petrescu, A., and P.
Thubert, "Network Mobility (NEMO) Basic Support Protocol",
RFC 3963, January 2005.
[RFC4301] Kent, S. and K. Seo, "Security Architecture for the
Internet Protocol", RFC 4301, December 2005.
[RFC4306] Kaufman, C., "Internet Key Exchange (IKEv2) Protocol",
RFC 4306, December 2005.
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Appendix A. PF_KEY MIGRATE Message Format
The figure below shows the message format of PF_KEY MIGRATE. The
message consists of 6 parts (boundary of each part is marked with
">"). The message starts with PF_KEY base message header followed by
two address extensions. A pair of address extensions hold source and
destination address of the selector. Rest of the message are
specific to IPsec implementation on BSD. 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_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 |
+---------------+---------------+---------------+---------------+
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| sadb_x_ipsecrequest_reserved2 |
+---------------+---------------+---------------+---------------+
~ old tunnel source address (64-bit aligned sockaddr) ~
+---------------+---------------+---------------+---------------+
~ old tunnel destination address (64-bit aligned sockaddr) ~
>+---------------+---------------+---------------+---------------+
| sadb_x_ipsecrequest_len | sadb_x_ipsecrequest_proto |
+---------------+---------------+---------------+---------------+
| ..._mode | ..._level | sadb_x_ipsecrequest_reserved1 |
+---------------+---------------+---------------+---------------+
| sadb_x_ipsecrequest_reqid |
+---------------+---------------+---------------+---------------+
| sadb_x_ipsecrequest_reserved2 |
+---------------+---------------+---------------+---------------+
~ new tunnel source address (64-bit aligned sockaddr) ~
+---------------+---------------+---------------+---------------+
~ new tunnel destination address (64-bit aligned sockaddr) ~
+---------------+---------------+---------------+---------------+
Following is a structure of PF_KEY base message header specified in
[RFC2367]. 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 a structure of address extension header specified in
[RFC2367]. 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 IPsec implementation.
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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 IPsec implementation.
IPsec protocol (ESP or AH) and mode (Tunnel) 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;
};
Appendix B. Acknowledgements
The authors gratefully acknowledge the contribution of: Kazunori
Miyazawa, Noriaki Takamiya, Shoichi Sakane, Mitsuru Kanda, Keiichi
Shima, Tsuyoshi Momose and other members from USAGI Project and KAME
Project.
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Authors' Addresses
Shinta Sugimoto
Nippon Ericsson K.K.
Koraku Mori Building
1-4-14, Koraku, Bunkyo-ku
Tokyo 112-0004
Japan
Phone: +81 3 3830 2241
Email: shinta.sugimoto@ericsson.com
Francis Dupont
CELAR
Email: Francis.Dupont@fdupont.fr
Masahide Nakamura
Hitachi Communication Technologies, Ltd.
216 Totsuka-cho, Totsuka-ku
Yokohama 244-8567
Japan
Phone: +81 45 865 7003
Email: masahide.nakamura.cz@hitachi.com
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