draft-ietf-hip-rfc5206-bis-08.txt   draft-ietf-hip-rfc5206-bis-09.txt 
Network Working Group T. Henderson, Ed. Network Working Group T. Henderson, Ed.
Internet-Draft University of Washington Internet-Draft University of Washington
Obsoletes: 5206 (if approved) C. Vogt Obsoletes: 5206 (if approved) C. Vogt
Intended status: Standards Track J. Arkko Intended status: Standards Track J. Arkko
Expires: July 16, 2015 Ericsson Research NomadicLab Expires: January 23, 2016 Ericsson Research NomadicLab
January 12, 2015 July 22, 2015
Host Mobility with the Host Identity Protocol Host Mobility with the Host Identity Protocol
draft-ietf-hip-rfc5206-bis-08 draft-ietf-hip-rfc5206-bis-09
Abstract Abstract
This document defines mobility extensions to the Host Identity This document defines mobility extensions to the Host Identity
Protocol (HIP). Specifically, this document defines a general Protocol (HIP). Specifically, this document defines a general
"LOCATOR_SET" parameter for HIP messages that allows for a HIP host "LOCATOR_SET" parameter for HIP messages that allows for a HIP host
to notify peers about alternate addresses at which it may be reached. to notify peers about alternate addresses at which it may be reached.
This document also defines elements of procedure for mobility of a This document also defines elements of procedure for mobility of a
HIP host -- the process by which a host dynamically changes the HIP host -- the process by which a host dynamically changes the
primary locator that it uses to receive packets. While the same primary locator that it uses to receive packets. While the same
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on July 16, 2015. This Internet-Draft will expire on January 23, 2016.
Copyright Notice Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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1. Introduction and Scope . . . . . . . . . . . . . . . . . . . 3 1. Introduction and Scope . . . . . . . . . . . . . . . . . . . 3
2. Terminology and Conventions . . . . . . . . . . . . . . . . . 4 2. Terminology and Conventions . . . . . . . . . . . . . . . . . 4
3. Protocol Model . . . . . . . . . . . . . . . . . . . . . . . 5 3. Protocol Model . . . . . . . . . . . . . . . . . . . . . . . 5
3.1. Operating Environment . . . . . . . . . . . . . . . . . . 5 3.1. Operating Environment . . . . . . . . . . . . . . . . . . 5
3.1.1. Locator . . . . . . . . . . . . . . . . . . . . . . . 8 3.1.1. Locator . . . . . . . . . . . . . . . . . . . . . . . 8
3.1.2. Mobility Overview . . . . . . . . . . . . . . . . . . 8 3.1.2. Mobility Overview . . . . . . . . . . . . . . . . . . 8
3.2. Protocol Overview . . . . . . . . . . . . . . . . . . . . 9 3.2. Protocol Overview . . . . . . . . . . . . . . . . . . . . 9
3.2.1. Mobility with a Single SA Pair (No Rekeying) . . . . 9 3.2.1. Mobility with a Single SA Pair (No Rekeying) . . . . 9
3.2.2. Mobility with a Single SA Pair (Mobile-Initiated 3.2.2. Mobility with a Single SA Pair (Mobile-Initiated
Rekey) . . . . . . . . . . . . . . . . . . . . . . . 11 Rekey) . . . . . . . . . . . . . . . . . . . . . . . 11
3.2.3. Network Renumbering . . . . . . . . . . . . . . . . . 11 3.2.3. Mobility messaging through rendezvous server . . . . 11
3.3. Other Considerations . . . . . . . . . . . . . . . . . . 11 3.2.4. Network Renumbering . . . . . . . . . . . . . . . . . 12
3.3.1. Address Verification . . . . . . . . . . . . . . . . 12 3.3. Other Considerations . . . . . . . . . . . . . . . . . . 13
3.3.2. Credit-Based Authorization . . . . . . . . . . . . . 12 3.3.1. Address Verification . . . . . . . . . . . . . . . . 13
3.3.3. Preferred Locator . . . . . . . . . . . . . . . . . . 13 3.3.2. Credit-Based Authorization . . . . . . . . . . . . . 13
4. LOCATOR_SET Parameter Format . . . . . . . . . . . . . . . . 14 3.3.3. Preferred Locator . . . . . . . . . . . . . . . . . . 14
4.1. Traffic Type and Preferred Locator . . . . . . . . . . . 15 4. LOCATOR_SET Parameter Format . . . . . . . . . . . . . . . . 15
4.2. Locator Type and Locator . . . . . . . . . . . . . . . . 16 4.1. Traffic Type and Preferred Locator . . . . . . . . . . . 16
4.3. UPDATE Packet with Included LOCATOR_SET . . . . . . . . . 16 4.2. Locator Type and Locator . . . . . . . . . . . . . . . . 17
5. Processing Rules . . . . . . . . . . . . . . . . . . . . . . 16 4.3. UPDATE Packet with Included LOCATOR_SET . . . . . . . . . 17
5.1. Locator Data Structure and Status . . . . . . . . . . . . 16 5. Processing Rules . . . . . . . . . . . . . . . . . . . . . . 17
5.2. Sending LOCATOR_SETs . . . . . . . . . . . . . . . . . . 18 5.1. Locator Data Structure and Status . . . . . . . . . . . . 17
5.3. Handling Received LOCATOR_SETs . . . . . . . . . . . . . 19 5.2. Sending LOCATOR_SETs . . . . . . . . . . . . . . . . . . 19
5.4. Verifying Address Reachability . . . . . . . . . . . . . 21 5.3. Handling Received LOCATOR_SETs . . . . . . . . . . . . . 20
5.5. Changing the Preferred Locator . . . . . . . . . . . . . 22 5.4. Verifying Address Reachability . . . . . . . . . . . . . 22
5.6. Credit-Based Authorization . . . . . . . . . . . . . . . 23 5.5. Changing the Preferred Locator . . . . . . . . . . . . . 23
5.6.1. Handling Payload Packets . . . . . . . . . . . . . . 23 5.6. Credit-Based Authorization . . . . . . . . . . . . . . . 24
5.6.2. Credit Aging . . . . . . . . . . . . . . . . . . . . 25 5.6.1. Handling Payload Packets . . . . . . . . . . . . . . 24
6. Security Considerations . . . . . . . . . . . . . . . . . . . 26 5.6.2. Credit Aging . . . . . . . . . . . . . . . . . . . . 26
6.1. Impersonation Attacks . . . . . . . . . . . . . . . . . . 27 6. Security Considerations . . . . . . . . . . . . . . . . . . . 27
6.2. Denial-of-Service Attacks . . . . . . . . . . . . . . . . 28 6.1. Impersonation Attacks . . . . . . . . . . . . . . . . . . 28
6.2.1. Flooding Attacks . . . . . . . . . . . . . . . . . . 28 6.2. Denial-of-Service Attacks . . . . . . . . . . . . . . . . 29
6.2.2. Memory/Computational-Exhaustion DoS Attacks . . . . . 28 6.2.1. Flooding Attacks . . . . . . . . . . . . . . . . . . 29
6.3. Mixed Deployment Environment . . . . . . . . . . . . . . 29 6.2.2. Memory/Computational-Exhaustion DoS Attacks . . . . . 29
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 29 6.3. Mixed Deployment Environment . . . . . . . . . . . . . . 30
8. Authors and Acknowledgments . . . . . . . . . . . . . . . . . 30 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 30
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 30 8. Authors and Acknowledgments . . . . . . . . . . . . . . . . . 31
9.1. Normative references . . . . . . . . . . . . . . . . . . 30 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 31
9.2. Informative references . . . . . . . . . . . . . . . . . 30 9.1. Normative references . . . . . . . . . . . . . . . . . . 31
Appendix A. Document Revision History . . . . . . . . . . . . . 32 9.2. Informative references . . . . . . . . . . . . . . . . . 32
Appendix A. Document Revision History . . . . . . . . . . . . . 33
1. Introduction and Scope 1. Introduction and Scope
The Host Identity Protocol [I-D.ietf-hip-rfc4423-bis] (HIP) supports The Host Identity Protocol [I-D.ietf-hip-rfc4423-bis] (HIP) supports
an architecture that decouples the transport layer (TCP, UDP, etc.) an architecture that decouples the transport layer (TCP, UDP, etc.)
from the internetworking layer (IPv4 and IPv6) by using public/ from the internetworking layer (IPv4 and IPv6) by using public/
private key pairs, instead of IP addresses, as host identities. When private key pairs, instead of IP addresses, as host identities. When
a host uses HIP, the overlying protocol sublayers (e.g., transport a host uses HIP, the overlying protocol sublayers (e.g., transport
layer sockets and Encapsulating Security Payload (ESP) Security layer sockets and Encapsulating Security Payload (ESP) Security
Associations (SAs)) are instead bound to representations of these Associations (SAs)) are instead bound to representations of these
host identities, and the IP addresses are only used for packet host identities, and the IP addresses are only used for packet
forwarding. However, each host must also know at least one IP forwarding. However, each host must also know at least one IP
address at which its peers are reachable. Initially, these IP address at which its peers are reachable. Initially, these IP
addresses are the ones used during the HIP base exchange addresses are the ones used during the HIP base exchange [RFC7401].
[I-D.ietf-hip-rfc5201-bis].
One consequence of such a decoupling is that new solutions to One consequence of such a decoupling is that new solutions to
network-layer mobility and host multihoming are possible. There are network-layer mobility and host multihoming are possible. There are
potentially many variations of mobility and multihoming possible. potentially many variations of mobility and multihoming possible.
The scope of this document encompasses messaging and elements of The scope of this document encompasses messaging and elements of
procedure for basic network-level host mobility, leaving more procedure for basic network-level host mobility, leaving more
complicated mobility scenarios, multihoming, and other variations for complicated mobility scenarios, multihoming, and other variations for
further study. More specifically: further study. More specifically:
This document defines a generalized LOCATOR_SET parameter for use This document defines a generalized LOCATOR_SET parameter for use
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change in the preferred IP address used to reach a host. In change in the preferred IP address used to reach a host. In
particular, message flows to enable successful host mobility, particular, message flows to enable successful host mobility,
including address verification methods, are defined herein. including address verification methods, are defined herein.
However, while the same LOCATOR_SET parameter is intended to However, while the same LOCATOR_SET parameter is intended to
support host multihoming (simultaneous use of a number of support host multihoming (simultaneous use of a number of
addresses), detailed elements of procedure for host multihoming addresses), detailed elements of procedure for host multihoming
are out of scope. are out of scope.
While HIP can potentially be used with transports other than the ESP While HIP can potentially be used with transports other than the ESP
transport format [I-D.ietf-hip-rfc5202-bis], this document largely transport format [RFC7402], this document largely assumes the use of
assumes the use of ESP and leaves other transport formats for further ESP and leaves other transport formats for further study.
study.
There are a number of situations where the simple end-to-end There are a number of situations where the simple end-to-end
readdressing functionality is not sufficient. These include the readdressing functionality is not sufficient. These include the
initial reachability of a mobile host, location privacy, simultaneous initial reachability of a mobile host, location privacy, simultaneous
mobility of both hosts, and some modes of NAT traversal. In these mobility of both hosts, and some modes of NAT traversal. In these
situations, there is a need for some helper functionality in the situations, there is a need for some helper functionality in the
network, such as a HIP rendezvous server [I-D.ietf-hip-rfc5204-bis]. network, such as a HIP rendezvous server [I-D.ietf-hip-rfc5204-bis].
Such functionality is out of the scope of this document. We also do Use of the HIP rendezvous server to manage the simultaneous mobility
not consider localized mobility management extensions (i.e., mobility of both hosts is specified herein, but other such scenarios are out
management techniques that do not involve directly signaling the of scope for this document. We also do not consider localized
correspondent node); this document is concerned with end-to-end mobility management extensions (i.e., mobility management techniques
mobility. Making underlying IP mobility transparent to the transport that do not involve directly signaling the correspondent node); this
layer has implications on the proper response of transport congestion document is concerned with end-to-end mobility. Making underlying IP
control, path MTU selection, and Quality of Service (QoS). mobility transparent to the transport layer has implications on the
Transport-layer mobility triggers, and the proper transport response proper response of transport congestion control, path MTU selection,
to a HIP mobility or multihoming address change, are outside the and Quality of Service (QoS). Transport-layer mobility triggers, and
scope of this document. the proper transport response to a HIP mobility or multihoming
address change, are outside the scope of this document.
2. Terminology and Conventions 2. Terminology and Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
LOCATOR_SET. The name of a HIP parameter containing zero or more LOCATOR_SET. The name of a HIP parameter containing zero or more
Locator fields. Locator fields.
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authorizes the peer to receive a certain amount of data at the new authorizes the peer to receive a certain amount of data at the new
locator before the result of such verification is known. locator before the result of such verification is known.
3. Protocol Model 3. Protocol Model
This section is an overview; more detailed specification follows this This section is an overview; more detailed specification follows this
section. section.
3.1. Operating Environment 3.1. Operating Environment
The Host Identity Protocol (HIP) [I-D.ietf-hip-rfc5201-bis] is a key The Host Identity Protocol (HIP) [RFC7401] is a key establishment and
establishment and parameter negotiation protocol. Its primary parameter negotiation protocol. Its primary applications are for
applications are for authenticating host messages based on host authenticating host messages based on host identities, and
identities, and establishing security associations (SAs) for the ESP establishing security associations (SAs) for the ESP transport format
transport format [I-D.ietf-hip-rfc5202-bis] and possibly other [RFC7402] and possibly other protocols in the future.
protocols in the future.
+--------------------+ +--------------------+ +--------------------+ +--------------------+
| | | | | | | |
| +------------+ | | +------------+ | | +------------+ | | +------------+ |
| | Key | | HIP | | Key | | | | Key | | HIP | | Key | |
| | Management | <-+-----------------------+-> | Management | | | | Management | <-+-----------------------+-> | Management | |
| | Process | | | | Process | | | | Process | | | | Process | |
| +------------+ | | +------------+ | | +------------+ | | +------------+ |
| ^ | | ^ | | ^ | | ^ |
| | | | | | | | | | | |
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Figure 2 depicts a layered architectural view of a HIP-enabled stack Figure 2 depicts a layered architectural view of a HIP-enabled stack
using the ESP transport format. In HIP, upper-layer protocols using the ESP transport format. In HIP, upper-layer protocols
(including TCP and ESP in this figure) are bound to Host Identity (including TCP and ESP in this figure) are bound to Host Identity
Tags (HITs) and not IP addresses. The HIP sublayer is responsible Tags (HITs) and not IP addresses. The HIP sublayer is responsible
for maintaining the binding between HITs and IP addresses. The SPI for maintaining the binding between HITs and IP addresses. The SPI
is used to associate an incoming packet with the right HITs. The is used to associate an incoming packet with the right HITs. The
block labeled "MH" is introduced below. block labeled "MH" is introduced below.
Consider first the case in which there is no mobility or multihoming, Consider first the case in which there is no mobility or multihoming,
as specified in the base protocol specification as specified in the base protocol specification [RFC7401]. The HIP
[I-D.ietf-hip-rfc5201-bis]. The HIP base exchange establishes the base exchange establishes the HITs in use between the hosts, the SPIs
HITs in use between the hosts, the SPIs to use for ESP, and the IP to use for ESP, and the IP addresses (used in both the HIP signaling
addresses (used in both the HIP signaling packets and ESP data packets and ESP data packets). Note that there can only be one such
packets). Note that there can only be one such set of bindings in set of bindings in the outbound direction for any given packet, and
the outbound direction for any given packet, and the only fields used the only fields used for the binding at the HIP layer are the fields
for the binding at the HIP layer are the fields exposed by ESP (the exposed by ESP (the SPI and HITs). For the inbound direction, the
SPI and HITs). For the inbound direction, the SPI is all that is SPI is all that is required to find the right host context. ESP
required to find the right host context. ESP rekeying events change rekeying events change the mapping between the HIT pair and SPI, but
the mapping between the HIT pair and SPI, but do not change the IP do not change the IP addresses.
addresses.
Consider next a mobility event, in which a host moves to another IP Consider next a mobility event, in which a host moves to another IP
address. Two things must occur in this case. First, the peer must address. Two things must occur in this case. First, the peer must
be notified of the address change using a HIP UPDATE message. be notified of the address change using a HIP UPDATE message.
Second, each host must change its local bindings at the HIP sublayer Second, each host must change its local bindings at the HIP sublayer
(new IP addresses). It may be that both the SPIs and IP addresses (new IP addresses). It may be that both the SPIs and IP addresses
are changed simultaneously in a single UPDATE; the protocol described are changed simultaneously in a single UPDATE; the protocol described
herein supports this. However, simultaneous movement of both hosts, herein supports this. However, simultaneous movement of both hosts,
notification of transport layer protocols of the path change, and notification of transport layer protocols of the path change, and
procedures for possibly traversing middleboxes are not covered by procedures for possibly traversing middleboxes are not covered by
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tunneling scenarios. Locators may simply be traditional network tunneling scenarios. Locators may simply be traditional network
addresses. The format of the locator fields in the LOCATOR_SET addresses. The format of the locator fields in the LOCATOR_SET
parameter is defined in Section 4. parameter is defined in Section 4.
3.1.2. Mobility Overview 3.1.2. Mobility Overview
When a host moves to another address, it notifies its peer of the new When a host moves to another address, it notifies its peer of the new
address by sending a HIP UPDATE packet containing a LOCATOR_SET address by sending a HIP UPDATE packet containing a LOCATOR_SET
parameter. This UPDATE packet is acknowledged by the peer. For parameter. This UPDATE packet is acknowledged by the peer. For
reliability in the presence of packet loss, the UPDATE packet is reliability in the presence of packet loss, the UPDATE packet is
retransmitted as defined in the HIP protocol specification retransmitted as defined in the HIP protocol specification [RFC7401].
[I-D.ietf-hip-rfc5201-bis]. The peer can authenticate the contents The peer can authenticate the contents of the UPDATE packet based on
of the UPDATE packet based on the signature and keyed hash of the the signature and keyed hash of the packet.
packet.
When using ESP Transport Format [I-D.ietf-hip-rfc5202-bis], the host When using ESP Transport Format [RFC7402], the host may at the same
may at the same time decide to rekey its security association and time decide to rekey its security association and possibly generate a
possibly generate a new Diffie-Hellman key; all of these actions are new Diffie-Hellman key; all of these actions are triggered by
triggered by including additional parameters in the UPDATE packet, as including additional parameters in the UPDATE packet, as defined in
defined in the base protocol specification [I-D.ietf-hip-rfc5201-bis] the base protocol specification [RFC7401] and ESP extension
and ESP extension [I-D.ietf-hip-rfc5202-bis]. [RFC7402].
When using ESP (and possibly other transport modes in the future), When using ESP (and possibly other transport modes in the future),
the host is able to receive packets that are protected using a HIP the host is able to receive packets that are protected using a HIP
created ESP SA from any address. Thus, a host can change its IP created ESP SA from any address. Thus, a host can change its IP
address and continue to send packets to its peers without necessarily address and continue to send packets to its peers without necessarily
rekeying. However, the peers are not able to send packets to these rekeying. However, the peers are not able to send packets to these
new addresses before they can reliably and securely update the set of new addresses before they can reliably and securely update the set of
addresses that they associate with the sending host. Furthermore, addresses that they associate with the sending host. Furthermore,
mobility may change the path characteristics in such a manner that mobility may change the path characteristics in such a manner that
reordering occurs and packets fall outside the ESP anti-replay window reordering occurs and packets fall outside the ESP anti-replay window
for the SA, thereby requiring rekeying. for the SA, thereby requiring rekeying.
3.2. Protocol Overview 3.2. Protocol Overview
In this section, we briefly introduce a number of usage scenarios for In this section, we briefly introduce a number of usage scenarios for
HIP host mobility. These scenarios assume that HIP is being used HIP host mobility. These scenarios assume that HIP is being used
with the ESP transform [I-D.ietf-hip-rfc5202-bis], although other with the ESP transform [RFC7402], although other scenarios may be
scenarios may be defined in the future. To understand these usage defined in the future. To understand these usage scenarios, the
scenarios, the reader should be at least minimally familiar with the reader should be at least minimally familiar with the HIP protocol
HIP protocol specification [I-D.ietf-hip-rfc5201-bis]. However, for specification [RFC7401]. However, for the (relatively) uninitiated
the (relatively) uninitiated reader, it is most important to keep in reader, it is most important to keep in mind that in HIP the actual
mind that in HIP the actual payload traffic is protected with ESP, payload traffic is protected with ESP, and that the ESP SPI acts as
and that the ESP SPI acts as an index to the right host-to-host an index to the right host-to-host context. More specification
context. More specification details are found later in Section 4 and details are found later in Section 4 and Section 5.
Section 5.
The scenarios below assume that the two hosts have completed a single The scenarios below assume that the two hosts have completed a single
HIP base exchange with each other. Both of the hosts therefore have HIP base exchange with each other. Both of the hosts therefore have
one incoming and one outgoing SA. Further, each SA uses the same one incoming and one outgoing SA. Further, each SA uses the same
pair of IP addresses, which are the ones used in the base exchange. pair of IP addresses, which are the ones used in the base exchange.
The readdressing protocol is an asymmetric protocol where a mobile The readdressing protocol is an asymmetric protocol where a mobile
host informs a peer host about changes of IP addresses on affected host informs a peer host about changes of IP addresses on affected
SPIs. The readdressing exchange is designed to be piggybacked on SPIs. The readdressing exchange is designed to be piggybacked on
existing HIP exchanges. The majority of the packets on which the existing HIP exchanges. The majority of the packets on which the
skipping to change at page 10, line 39 skipping to change at page 10, line 38
message. The UPDATE message also contains an ESP_INFO parameter message. The UPDATE message also contains an ESP_INFO parameter
containing the values of the old and new SPIs for a security containing the values of the old and new SPIs for a security
association. In this case, the OLD SPI and NEW SPI parameters association. In this case, the OLD SPI and NEW SPI parameters
both are set to the value of the preexisting incoming SPI; this both are set to the value of the preexisting incoming SPI; this
ESP_INFO does not trigger a rekeying event but is instead ESP_INFO does not trigger a rekeying event but is instead
included for possible parameter-inspecting middleboxes on the included for possible parameter-inspecting middleboxes on the
path. The LOCATOR_SET parameter contains the new IP address path. The LOCATOR_SET parameter contains the new IP address
(Locator Type of "1", defined below) and a locator lifetime. The (Locator Type of "1", defined below) and a locator lifetime. The
mobile host waits for this UPDATE to be acknowledged, and mobile host waits for this UPDATE to be acknowledged, and
retransmits if necessary, as specified in the base specification retransmits if necessary, as specified in the base specification
[I-D.ietf-hip-rfc5201-bis]. [RFC7401].
2. The peer host receives the UPDATE, validates it, and updates any 2. The peer host receives the UPDATE, validates it, and updates any
local bindings between the HIP association and the mobile host's local bindings between the HIP association and the mobile host's
destination address. The peer host MUST perform an address destination address. The peer host MUST perform an address
verification by placing a nonce in the ECHO_REQUEST parameter of verification by placing a nonce in the ECHO_REQUEST parameter of
the UPDATE message sent back to the mobile host. It also the UPDATE message sent back to the mobile host. It also
includes an ESP_INFO parameter with the OLD SPI and NEW SPI includes an ESP_INFO parameter with the OLD SPI and NEW SPI
parameters both set to the value of the preexisting incoming SPI, parameters both set to the value of the preexisting incoming SPI,
and sends this UPDATE (with piggybacked acknowledgment) to the and sends this UPDATE (with piggybacked acknowledgment) to the
mobile host at its new address. The peer MAY use the new address mobile host at its new address. The peer MAY use the new address
skipping to change at page 11, line 41 skipping to change at page 11, line 41
UPDATE(ESP_INFO, LOCATOR_SET, SEQ, [DIFFIE_HELLMAN]) UPDATE(ESP_INFO, LOCATOR_SET, SEQ, [DIFFIE_HELLMAN])
-----------------------------------> ----------------------------------->
UPDATE(ESP_INFO, SEQ, ACK, [DIFFIE_HELLMAN,] ECHO_REQUEST) UPDATE(ESP_INFO, SEQ, ACK, [DIFFIE_HELLMAN,] ECHO_REQUEST)
<----------------------------------- <-----------------------------------
UPDATE(ACK, ECHO_RESPONSE) UPDATE(ACK, ECHO_RESPONSE)
-----------------------------------> ----------------------------------->
Figure 4: Readdress with Mobile-Initiated Rekey Figure 4: Readdress with Mobile-Initiated Rekey
3.2.3. Network Renumbering 3.2.3. Mobility messaging through rendezvous server
Section 6.11 of [RFC7401] specifies procedures for sending HIP UPDATE
packets. The UPDATE packets are protected by a timer subject to
exponential backoff and resent UPDATE_RETRY_MAX times. It may be,
however, that the peer is itself in the process of moving when the
local host is trying to update the IP address bindings of the HIP
association. This is sometimes called the "double-jump" mobility
problem; each host's UPDATE packets are simultaneously sent to a
stale address of the peer, and the hosts are no longer reachable from
one another.
The HIP Rendezvous Extension [I-D.ietf-hip-rfc5204-bis] specifies a
rendezvous service that permits the I1 packet from the base exchange
to be relayed from a stable or well-known public IP address location
to the current IP address of the host. It is possible to support
double-jump mobility with this rendezvous service if the following
extensions to the specifications of [I-D.ietf-hip-rfc5204-bis] and
[RFC7401] are followed.
1. The mobile host sending an UPDATE to the peer, and not receiving
an ACK, MAY resend the UPDATE to a rendezvous server (RVS) of the
peer, if such a server is known. The host may try the RVS of the
peer up to UPDATE_RETRY_MAX times as specified in [RFC7401]. The
host may try to use the peer's RVS before it has tried
UPDATE_RETRY_MAX times to the last working address (i.e. the RVS
may be tried in parallel with retries to the last working
address).
2. A rendezvous server supporting the UPDATE forwarding extensions
specified herein MUST modify the UPDATE in the same manner as it
modifies the I1 packet before forwarding. Specifically, it MUST
rewrite the IP header source and destination addresses, recompute
the IP header checksum, and include the FROM and RVS_HMAC
parameters.
3. A host receiving an UPDATE packet MUST be prepared to process the
FROM and RVS_HMAC parameters, and MUST include a VIA_RVS
parameter in the UPDATE reply that contains the ACK of the UPDATE
SEQ.
4. This scenario requires that hosts using rendezvous servers also
take steps to update their current address bindings with their
rendezvous server upon a mobility event.
[I-D.ietf-hip-rfc5204-bis] does not specify how to update the
rendezvous server with a client host's new address.
[I-D.ietf-hip-rfc5203-bis] Section 3.2 describes how a host may
send a REG_REQUEST in either an I2 packet (if there is no active
association) or an UPDATE packet (if such association exists).
The procedures described in [I-D.ietf-hip-rfc5203-bis] for
sending a REG_REQUEST and REG_RESPONSE to the rendezvous server
apply also to this mobility scenario.
3.2.4. Network Renumbering
It is expected that IPv6 networks will be renumbered much more often It is expected that IPv6 networks will be renumbered much more often
than most IPv4 networks. From an end-host point of view, network than most IPv4 networks. From an end-host point of view, network
renumbering is similar to mobility. renumbering is similar to mobility.
3.3. Other Considerations 3.3. Other Considerations
3.3.1. Address Verification 3.3.1. Address Verification
When a HIP host receives a set of locators from another HIP host in a When a HIP host receives a set of locators from another HIP host in a
LOCATOR_SET, it does not necessarily know whether the other host is LOCATOR_SET, it does not necessarily know whether the other host is
actually reachable at the claimed addresses. In fact, a malicious actually reachable at the claimed addresses. In fact, a malicious
peer host may be intentionally giving bogus addresses in order to peer host may be intentionally giving bogus addresses in order to
cause a packet flood towards the target addresses [RFC4225]. cause a packet flood towards the target addresses [RFC4225].
Therefore, the HIP host must first check that the peer is reachable Therefore, the HIP host must first check that the peer is reachable
at the new address. at the new address.
skipping to change at page 14, line 8 skipping to change at page 15, line 8
When a host has multiple locators, the peer host must decide which to When a host has multiple locators, the peer host must decide which to
use for outbound packets. It may be that a host would prefer to use for outbound packets. It may be that a host would prefer to
receive data on a particular inbound interface. HIP allows a receive data on a particular inbound interface. HIP allows a
particular locator to be designated as a Preferred locator and particular locator to be designated as a Preferred locator and
communicated to the peer (see Section 4). communicated to the peer (see Section 4).
4. LOCATOR_SET Parameter Format 4. LOCATOR_SET Parameter Format
The LOCATOR_SET parameter is a critical parameter as defined by The LOCATOR_SET parameter is a critical parameter as defined by
[I-D.ietf-hip-rfc5201-bis]. It consists of the standard HIP [RFC7401]. It consists of the standard HIP parameter Type and Length
parameter Type and Length fields, plus zero or more Locator sub- fields, plus zero or more Locator sub-parameters. Each Locator sub-
parameters. Each Locator sub-parameter contains a Traffic Type, parameter contains a Traffic Type, Locator Type, Locator Length,
Locator Type, Locator Length, Preferred locator bit, Locator Preferred locator bit, Locator Lifetime, and a Locator encoding. A
Lifetime, and a Locator encoding. A LOCATOR_SET containing zero LOCATOR_SET containing zero Locator fields is permitted but has the
Locator fields is permitted but has the effect of deprecating all effect of deprecating all addresses.
addresses.
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Traffic Type | Locator Type | Locator Length | Reserved |P| | Traffic Type | Locator Type | Locator Length | Reserved |P|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Locator Lifetime | | Locator Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 18, line 33 skipping to change at page 19, line 33
1. Host mobility with no multihoming and no rekeying. The mobile 1. Host mobility with no multihoming and no rekeying. The mobile
host creates a single UPDATE containing a single ESP_INFO with a host creates a single UPDATE containing a single ESP_INFO with a
single LOCATOR_SET parameter. The ESP_INFO contains the current single LOCATOR_SET parameter. The ESP_INFO contains the current
value of the SPI in both the OLD SPI and NEW SPI fields. The value of the SPI in both the OLD SPI and NEW SPI fields. The
LOCATOR_SET contains a single Locator with a "Locator Type" of LOCATOR_SET contains a single Locator with a "Locator Type" of
"1"; the SPI must match that of the ESP_INFO. The Preferred bit "1"; the SPI must match that of the ESP_INFO. The Preferred bit
SHOULD be set and the "Locator Lifetime" is set according to SHOULD be set and the "Locator Lifetime" is set according to
local policy. The UPDATE also contains a SEQ parameter as usual. local policy. The UPDATE also contains a SEQ parameter as usual.
This packet is retransmitted as defined in the HIP protocol This packet is retransmitted as defined in the HIP protocol
specification [I-D.ietf-hip-rfc5201-bis]. The UPDATE should be specification [RFC7401]. The UPDATE should be sent to the peer's
sent to the peer's preferred IP address with an IP source address preferred IP address with an IP source address corresponding to
corresponding to the address in the LOCATOR_SET parameter. the address in the LOCATOR_SET parameter.
2. Host mobility with no multihoming but with rekeying. The mobile 2. Host mobility with no multihoming but with rekeying. The mobile
host creates a single UPDATE containing a single ESP_INFO with a host creates a single UPDATE containing a single ESP_INFO with a
single LOCATOR_SET parameter (with a single address). The single LOCATOR_SET parameter (with a single address). The
ESP_INFO contains the current value of the SPI in the OLD SPI and ESP_INFO contains the current value of the SPI in the OLD SPI and
the new value of the SPI in the NEW SPI, and a KEYMAT Index as the new value of the SPI in the NEW SPI, and a KEYMAT Index as
selected by local policy. Optionally, the host may choose to selected by local policy. Optionally, the host may choose to
initiate a Diffie Hellman rekey by including a DIFFIE_HELLMAN initiate a Diffie Hellman rekey by including a DIFFIE_HELLMAN
parameter. The LOCATOR_SET contains a single Locator with parameter. The LOCATOR_SET contains a single Locator with
"Locator Type" of "1"; the SPI must match that of the NEW SPI in "Locator Type" of "1"; the SPI must match that of the NEW SPI in
skipping to change at page 26, line 31 skipping to change at page 27, line 31
the peer via a TCP connection and the end-to-end round-trip time does the peer via a TCP connection and the end-to-end round-trip time does
not exceed 500 milliseconds. Alternative credit-aging algorithms may not exceed 500 milliseconds. Alternative credit-aging algorithms may
use other parameter values or different parameters, which may even be use other parameter values or different parameters, which may even be
dynamically established. dynamically established.
6. Security Considerations 6. Security Considerations
The HIP mobility mechanism provides a secure means of updating a The HIP mobility mechanism provides a secure means of updating a
host's IP address via HIP UPDATE packets. Upon receipt, a HIP host host's IP address via HIP UPDATE packets. Upon receipt, a HIP host
cryptographically verifies the sender of an UPDATE, so forging or cryptographically verifies the sender of an UPDATE, so forging or
replaying a HIP UPDATE packet is very difficult (see replaying a HIP UPDATE packet is very difficult (see [RFC7401]).
[I-D.ietf-hip-rfc5201-bis]). Therefore, security issues reside in Therefore, security issues reside in other attack domains. The two
other attack domains. The two we consider are malicious redirection we consider are malicious redirection of legitimate connections as
of legitimate connections as well as redirection-based flooding well as redirection-based flooding attacks using this protocol. This
attacks using this protocol. This can be broken down into the can be broken down into the following:
following:
Impersonation attacks Impersonation attacks
- direct conversation with the misled victim - direct conversation with the misled victim
- man-in-the-middle attack - man-in-the-middle attack
DoS attacks DoS attacks
- flooding attacks (== bandwidth-exhaustion attacks) - flooding attacks (== bandwidth-exhaustion attacks)
skipping to change at page 27, line 34 skipping to change at page 28, line 34
the attacker tricks its victim into initiating the connection over an the attacker tricks its victim into initiating the connection over an
incorrect routing path (e.g., by acting as a router or using spoofed incorrect routing path (e.g., by acting as a router or using spoofed
DNS entries). DNS entries).
The HIP extensions defined in this specification change the situation The HIP extensions defined in this specification change the situation
in that they introduce an ability to redirect a connection (like in that they introduce an ability to redirect a connection (like
IPv6), both before and after establishment. If no precautionary IPv6), both before and after establishment. If no precautionary
measures are taken, an attacker could misuse the redirection feature measures are taken, an attacker could misuse the redirection feature
to impersonate a victim's peer from any arbitrary location. The to impersonate a victim's peer from any arbitrary location. The
authentication and authorization mechanisms of the HIP base exchange authentication and authorization mechanisms of the HIP base exchange
[I-D.ietf-hip-rfc5201-bis] and the signatures in the UPDATE message [RFC7401] and the signatures in the UPDATE message prevent this
prevent this attack. Furthermore, ownership of a HIP association is attack. Furthermore, ownership of a HIP association is securely
securely linked to a HIP HI/HIT. If an attacker somehow uses a bug linked to a HIP HI/HIT. If an attacker somehow uses a bug in the
in the implementation or weakness in some protocol to redirect a HIP implementation or weakness in some protocol to redirect a HIP
connection, the original owner can always reclaim their connection connection, the original owner can always reclaim their connection
(they can always prove ownership of the private key associated with (they can always prove ownership of the private key associated with
their public HI). their public HI).
MitM attacks are always possible if the attacker is present during MitM attacks are always possible if the attacker is present during
the initial HIP base exchange and if the hosts do not authenticate the initial HIP base exchange and if the hosts do not authenticate
each other's identities. However, once the opportunistic base each other's identities. However, once the opportunistic base
exchange has taken place, even a MitM cannot steal the HIP connection exchange has taken place, even a MitM cannot steal the HIP connection
anymore because it is very difficult for an attacker to create an anymore because it is very difficult for an attacker to create an
UPDATE packet (or any HIP packet) that will be accepted as a UPDATE packet (or any HIP packet) that will be accepted as a
skipping to change at page 28, line 44 skipping to change at page 29, line 44
amplification in the number and size of the redirected packets. As a amplification in the number and size of the redirected packets. As a
result, the combination of a reachability check and credit-based result, the combination of a reachability check and credit-based
authorization lowers a HIP redirection-based flooding attack to the authorization lowers a HIP redirection-based flooding attack to the
level of a direct flooding attack in which the attacker itself sends level of a direct flooding attack in which the attacker itself sends
the flooding traffic to the victim. the flooding traffic to the victim.
6.2.2. Memory/Computational-Exhaustion DoS Attacks 6.2.2. Memory/Computational-Exhaustion DoS Attacks
We now consider whether or not the proposed extensions to HIP add any We now consider whether or not the proposed extensions to HIP add any
new DoS attacks (consideration of DoS attacks using the base HIP new DoS attacks (consideration of DoS attacks using the base HIP
exchange and updates is discussed in [I-D.ietf-hip-rfc5201-bis]). A exchange and updates is discussed in [RFC7401]). A simple attack is
simple attack is to send many UPDATE packets containing many IP to send many UPDATE packets containing many IP addresses that are not
addresses that are not flagged as preferred. The attacker continues flagged as preferred. The attacker continues to send such packets
to send such packets until the number of IP addresses associated with until the number of IP addresses associated with the attacker's HI
the attacker's HI crashes the system. Therefore, there SHOULD be a crashes the system. Therefore, there SHOULD be a limit to the number
limit to the number of IP addresses that can be associated with any of IP addresses that can be associated with any HI. Other forms of
HI. Other forms of memory/computationally exhausting attacks via the memory/computationally exhausting attacks via the HIP UPDATE packet
HIP UPDATE packet are handled in the base HIP document are handled in the base HIP document [RFC7401].
[I-D.ietf-hip-rfc5201-bis].
A central server that has to deal with a large number of mobile A central server that has to deal with a large number of mobile
clients may consider increasing the SA lifetimes to try to slow down clients may consider increasing the SA lifetimes to try to slow down
the rate of rekeying UPDATEs or increasing the cookie difficulty to the rate of rekeying UPDATEs or increasing the cookie difficulty to
slow down the rate of attack-oriented connections. slow down the rate of attack-oriented connections.
6.3. Mixed Deployment Environment 6.3. Mixed Deployment Environment
We now assume an environment with both HIP and non-HIP aware hosts. We now assume an environment with both HIP and non-HIP aware hosts.
Four cases exist. Four cases exist.
skipping to change at page 30, line 20 skipping to change at page 31, line 20
Jokela was a co-author of the initial individual submission. Jokela was a co-author of the initial individual submission.
The authors thank Jeff Ahrenholz, Baris Boyvat, Rene Hummen, Miika The authors thank Jeff Ahrenholz, Baris Boyvat, Rene Hummen, Miika
Komu, Mika Kousa, Jan Melen, and Samu Varjonen for improvements to Komu, Mika Kousa, Jan Melen, and Samu Varjonen for improvements to
the document. the document.
9. References 9. References
9.1. Normative references 9.1. Normative references
[I-D.ietf-hip-rfc5201-bis] [I-D.ietf-hip-rfc5203-bis]
Moskowitz, R., Heer, T., Jokela, P., and T. Henderson, Laganier, J. and L. Eggert, "Host Identity Protocol (HIP)
"Host Identity Protocol Version 2 (HIPv2)", draft-ietf- Registration Extension", draft-ietf-hip-rfc5203-bis-09
hip-rfc5201-bis-20 (work in progress), October 2014. (work in progress), June 2015.
[I-D.ietf-hip-rfc5202-bis]
Jokela, P., Moskowitz, R., and J. Melen, "Using the
Encapsulating Security Payload (ESP) Transport Format with
the Host Identity Protocol (HIP)", draft-ietf-hip-
rfc5202-bis-07 (work in progress), September 2014.
[I-D.ietf-hip-rfc5204-bis] [I-D.ietf-hip-rfc5204-bis]
Laganier, J. and L. Eggert, "Host Identity Protocol (HIP) Laganier, J. and L. Eggert, "Host Identity Protocol (HIP)
Rendezvous Extension", draft-ietf-hip-rfc5204-bis-05 (work Rendezvous Extension", draft-ietf-hip-rfc5204-bis-06 (work
in progress), December 2014. in progress), June 2015.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing
Architecture", RFC 4291, February 2006. Architecture", RFC 4291, DOI 10.17487/RFC4291, February
2006, <http://www.rfc-editor.org/info/rfc4291>.
[RFC7401] Moskowitz, R., Ed., Heer, T., Jokela, P., and T.
Henderson, "Host Identity Protocol Version 2 (HIPv2)", RFC
7401, DOI 10.17487/RFC7401, April 2015,
<http://www.rfc-editor.org/info/rfc7401>.
[RFC7402] Jokela, P., Moskowitz, R., and J. Melen, "Using the
Encapsulating Security Payload (ESP) Transport Format with
the Host Identity Protocol (HIP)", RFC 7402, DOI 10.17487/
RFC7402, April 2015,
<http://www.rfc-editor.org/info/rfc7402>.
9.2. Informative references 9.2. Informative references
[CBA-MIPv6] [CBA-MIPv6]
Vogt, C. and J. Arkko, "Credit-Based Authorization for Vogt, C. and J. Arkko, "Credit-Based Authorization for
Mobile IPv6 Early Binding Updates", February 2005. Mobile IPv6 Early Binding Updates", February 2005.
[I-D.ietf-hip-rfc4423-bis] [I-D.ietf-hip-rfc4423-bis]
Moskowitz, R. and M. Komu, "Host Identity Protocol Moskowitz, R. and M. Komu, "Host Identity Protocol
Architecture", draft-ietf-hip-rfc4423-bis-09 (work in Architecture", draft-ietf-hip-rfc4423-bis-12 (work in
progress), October 2014. progress), June 2015.
[RFC4225] Nikander, P., Arkko, J., Aura, T., Montenegro, G., and E. [RFC4225] Nikander, P., Arkko, J., Aura, T., Montenegro, G., and E.
Nordmark, "Mobile IP Version 6 Route Optimization Security Nordmark, "Mobile IP Version 6 Route Optimization Security
Design Background", RFC 4225, December 2005. Design Background", RFC 4225, DOI 10.17487/RFC4225,
December 2005, <http://www.rfc-editor.org/info/rfc4225>.
[SIMPLE-CBA] [SIMPLE-CBA]
Vogt, C. and J. Arkko, "Credit-Based Authorization for Vogt, C. and J. Arkko, "Credit-Based Authorization for
Concurrent Reachability Verification", February 2006. Concurrent Reachability Verification", February 2006.
Appendix A. Document Revision History Appendix A. Document Revision History
To be removed upon publication To be removed upon publication
+----------+--------------------------------------------------------+ +----------+--------------------------------------------------------+
skipping to change at page 32, line 43 skipping to change at page 33, line 43
| draft-07 | Document refresh; IANA considerations updated. | | draft-07 | Document refresh; IANA considerations updated. |
| | | | | |
| draft-08 | Remove sending LOCATOR_SET in R1, I2, and NOTIFY | | draft-08 | Remove sending LOCATOR_SET in R1, I2, and NOTIFY |
| | (multihoming) | | | (multihoming) |
| | | | | |
| | State that only one LOCATOR_SET parameter may be sent | | | State that only one LOCATOR_SET parameter may be sent |
| | in an UPDATE packet (according to this draft) | | | in an UPDATE packet (according to this draft) |
| | (multihoming) | | | (multihoming) |
| | | | | |
| | Remove text about cross-family handovers (multihoming) | | | Remove text about cross-family handovers (multihoming) |
| | |
| draft-09 | Add specification text regarding double-jump mobility |
| | procedures. |
+----------+--------------------------------------------------------+ +----------+--------------------------------------------------------+
Authors' Addresses Authors' Addresses
Thomas R. Henderson (editor) Thomas R. Henderson (editor)
University of Washington University of Washington
Campus Box 352500 Campus Box 352500
Seattle, WA Seattle, WA
USA USA
EMail: tomhend@u.washington.edu EMail: tomhend@u.washington.edu
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