draft-ietf-dhc-triggered-reconfigure-01.txt   draft-ietf-dhc-triggered-reconfigure-02.txt 
DHC Working Group M. Boucadair DHC Working Group M. Boucadair
Internet-Draft X. Pougnard Internet-Draft X. Pougnard
Updates: 3315, 6422 (if approved) France Telecom Updates: 3315, 6422 (if approved) France Telecom
Intended status: Standards Track September 28, 2012 Intended status: Standards Track December 17, 2012
Expires: April 1, 2013 Expires: June 20, 2013
RECONFIGURE Triggered by DHCPv6 Relay Agents RECONFIGURE Triggered by DHCPv6 Relay Agents
draft-ietf-dhc-triggered-reconfigure-01 draft-ietf-dhc-triggered-reconfigure-02
Abstract Abstract
This document defines a new DHCPv6 message type: RECONFIGURE-REQUEST. This document defines a new DHCPv6 message type: RECONFIGURE-REQUEST.
This message is sent by a DHCPv6 relay agent to notify a DHCPv6 This message is sent by a DHCPv6 relay agent to notify a DHCPv6
server about a configuration information change, so that the DHCPv6 server about a configuration information change, so that the DHCPv6
server can send a RECONFIGURE message accordingly. server can send a RECONFIGURE message accordingly.
This document updates RFC3315 and RFC6422. This document updates RFC3315 and RFC6422.
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This Internet-Draft will expire on April 1, 2013. This Internet-Draft will expire on June 20, 2013.
Copyright Notice Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the Copyright (c) 2012 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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include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Problem . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Problem . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2. Requirements Language . . . . . . . . . . . . . . . . . . . 4 1.2. Requirements Language . . . . . . . . . . . . . . . . . . . 4
2. Proposed Solution . . . . . . . . . . . . . . . . . . . . . . . 4 2. Proposed Solution . . . . . . . . . . . . . . . . . . . . . . . 4
3. RECONFIGURE-REQUEST . . . . . . . . . . . . . . . . . . . . . . 5 3. Link Address Option . . . . . . . . . . . . . . . . . . . . . . 5
3.1. Message Format . . . . . . . . . . . . . . . . . . . . . . 5 4. RECONFIGURE-REQUEST . . . . . . . . . . . . . . . . . . . . . . 6
3.2. Message Validation . . . . . . . . . . . . . . . . . . . . 5 4.1. Message Format . . . . . . . . . . . . . . . . . . . . . . 6
3.3. Creation and Transmission of RECONFIGURE-REQUEST . . . . . 6 4.2. Message Validation . . . . . . . . . . . . . . . . . . . . 6
3.4. Server Behaviour . . . . . . . . . . . . . . . . . . . . . 7 4.3. Creation and Transmission of RECONFIGURE-REQUEST . . . . . 7
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7 4.4. Server Behaviour . . . . . . . . . . . . . . . . . . . . . 8
5. Security Considerations . . . . . . . . . . . . . . . . . . . . 7 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 8
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7 6. Security Considerations . . . . . . . . . . . . . . . . . . . . 8
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 8 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 9
7.1. Normative References . . . . . . . . . . . . . . . . . . . 8 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9
7.2. Informative References . . . . . . . . . . . . . . . . . . 8 8.1. Normative References . . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8 8.2. Informative References . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction 1. Introduction
1.1. Problem 1.1. Problem
[RFC6422] updates the DHCPv6 specification [RFC3315] with a new [RFC6422] updates the DHCPv6 specification [RFC3315] with a new
feature to let a DHCPv6 relay agent communicate information towards a feature to let a DHCPv6 relay agent communicate information towards a
DHCPv6 Client, and which is not available at the DHCPv6 server. This DHCPv6 Client, and which is not available at the DHCPv6 server. This
is achieved owing to the use of RSOO (Relay-Supplied Options option) is achieved owing to the use of RSOO (Relay-Supplied Options option)
which carries configuration data to the DHCPv6 server. The data which carries configuration data to the DHCPv6 server. The data
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|<--Reconfigure-------------| (Reconfigure) | |<--Reconfigure-------------| (Reconfigure) |
| | | | | |
.... ....
Figure 3: RECONFIGURE-REQUEST Flow Example Figure 3: RECONFIGURE-REQUEST Flow Example
The Reconfigure-Request message can also be used in other scenarios The Reconfigure-Request message can also be used in other scenarios
than those that assume the use of RSOO. It is out of scope of this than those that assume the use of RSOO. It is out of scope of this
document to describe all these scenarios. document to describe all these scenarios.
3. RECONFIGURE-REQUEST 3. Link Address Option
3.1. Message Format Figure 4 shows the format of the Link Address Option.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_LINK_ADDRESS | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| link-address (IPv6 address) |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Message Format of Link Address Option
The description of the fields are as follows:
option-code: OPTION_LINK_ADDRESS (To be assigned by IANA, see
Section 5).
option-len: 16 (octets).
link-address: An IPv6 address used by the server to identify the
link on which the client is located.
The Link Address Option is used by the relay agent to indicate to the
server the link on which the client is located. The relay agent MUST
use a link-address value that is equivalent to the value used when
relaying messages from the client to the server. Two link-address
values are said to be equivalent if both values are IPv6 addresses
that are on-link for the network link to which the client is
connected. The relay agent SHOULD use the same value that was sent
to the DHCP server when relaying messages from the client to the
server, as in Section 20.1.1 of [RFC3315].
The relay agent MUST NOT use the IPv6 unspecified address (0::0) in
this option. The server MUST discard any Reconfigure Request message
containing a Link Address Option that carries the unspecified
address.
4. RECONFIGURE-REQUEST
4.1. Message Format
A new message type code is defined: A new message type code is defined:
RECONFIGURE-REQUEST (To be assigned by IANA, see Section 4). RECONFIGURE-REQUEST (To be assigned by IANA, see Section 5).
RECONFIGURE-REQUEST uses the same format as defined in Section 6 of RECONFIGURE-REQUEST uses the same format as defined in Section 6 of
[RFC3315]. [RFC3315].
3.2. Message Validation 4.2. Message Validation
Clients MUST silently discard any received RECONFIGURE-REQUEST Clients MUST silently discard any received RECONFIGURE-REQUEST
messages. messages.
Servers MUST silently discard any received RECONFIGURE-REQUEST Servers MUST silently discard any received RECONFIGURE-REQUEST
messages that meet any of the following conditions: messages that meet any of the following conditions:
o the message does not include an OPTION_CLIENTID option. o the message does not include a Client Identifier Option [RFC3315].
o the message includes an OPTION_SERVERID option but the contents of
the OPTION_SERVERID option does not match the server's identifier. o the message does not include a Link Address Option (Section 3).
o the message includes a Server Identifier Option [RFC3315] but the
contents of the Server Identifier Option does not match the
server's identifier.
The server MUST be configurable to accept or reject RECONFIGURE- The server MUST be configurable to accept or reject RECONFIGURE-
REQUEST messages. If the server is configured to reject RECONFIGURE- REQUEST messages. If the server is configured to reject RECONFIGURE-
REQUEST, the server MUST silently discard any RECONFIGURE-REQUEST it REQUEST, the server MUST silently discard any RECONFIGURE-REQUEST it
receives. receives.
The relay agent MUST be configurable to accept or reject RECONFIGURE- The relay agent MUST be configurable to accept or reject RECONFIGURE-
REQUEST messages received from other relay agents. If the relay is REQUEST messages received from other relay agents. If the relay is
configured to reject RECONFIGURE-REQUEST, the relay MUST silently configured to reject RECONFIGURE-REQUEST, the relay MUST silently
discard any RECONFIGURE-REQUEST it receives. If the relay is discard any RECONFIGURE-REQUEST it receives. If the relay is
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relayed as specified in Section 20.1.1 of [RFC3315]. relayed as specified in Section 20.1.1 of [RFC3315].
Because RECONFIGURE-REQUEST message provides a mechanism for Because RECONFIGURE-REQUEST message provides a mechanism for
triggering the DHCP Reconfigure message, and the DHCP Reconfigure triggering the DHCP Reconfigure message, and the DHCP Reconfigure
message can raise security threats (e.g., to control the timing of a message can raise security threats (e.g., to control the timing of a
DHCP renewal), the DHCP server MUST have some mechanism for DHCP renewal), the DHCP server MUST have some mechanism for
determining that the relay agent is a trusted entity. RECONFIGURE- determining that the relay agent is a trusted entity. RECONFIGURE-
REQUEST messages originating from unknown relay agents MUST be REQUEST messages originating from unknown relay agents MUST be
silently dropped. silently dropped.
3.3. Creation and Transmission of RECONFIGURE-REQUEST 4.3. Creation and Transmission of RECONFIGURE-REQUEST
For any event (e.g., modification of the configuration information) For any event (e.g., modification of the configuration information)
that requires the server to issue a Reconfigure message, the relay that requires the server to issue a Reconfigure message, the relay
agent determines the client which is affected by the change and then agent determines the client which is affected by the change and then
builds a Reconfigure-Request message: the relay agent sets the "msg- builds a Reconfigure-Request message: the relay agent sets the "msg-
type" field to RECONFIGURE-REQUEST and sets the "transaction-id " type" field to RECONFIGURE-REQUEST and sets the "transaction-id "
field to 0. The relay agent MUST include an OPTION_CLIENTID option field to 0. The relay agent MUST include a Client Identifier Option
[RFC3315] so that the DHCPv6 server can identify the corresponding [RFC3315] and a Link Address Option (Section 3) so that the DHCPv6
client. The relay agent MAY supply the updated configuration in the server can identify the corresponding client and the link on which
RSOO [RFC6422]. The relay agent MAY supply an OPTION_RECONF_MSG the client is located. The relay agent MAY supply the updated
option to indicate which form of Reconfigure to use. configuration in the RSOO [RFC6422]. The relay agent MAY supply a
Reconfigure Message Option to indicate which form of Reconfigure to
use.
When several clients are concerned with a configuration change, the When several clients on the same link are concerned with a
relay MUST include several OPTION_CLIENTID options, each of them configuration change, the relay MUST include several Client
identifies a specific client. If including OPTION_CLIENTID options Identifier Options, each of them identifies a specific client. If
of all impacted clients exceeds the maximum message size, the relay including Client Identifier Options of all impacted clients exceeds
MUST generate several RECONFIGURE-REQUEST messages required to carry the maximum message size, the relay MUST generate several
all OPTION_CLIENTID options. RECONFIGURE-REQUEST messages required to carry all Client Identifier
Options.
3.4. Server Behaviour 4.4. Server Behaviour
Upon receipt of a valid Reconfigure-Request message from a DHCPv6 Upon receipt of a valid Reconfigure-Request message from a DHCPv6
relay agent (see Section 3.2), the server determines the client(s) relay agent (see Section 4.2), the server determines the client(s)
for which a Reconfigure message is to be sent. for which a Reconfigure message is to be sent.
The server MAY use the content of the OPTION_RECONF_MSG option The server MAY use the content of the Reconfigure Message Option
supplied by the relay agent to determine which form of Reconfigure to supplied by the relay agent to determine which form of Reconfigure to
use. use.
If RSOO is supplied, the server MAY use its content to double check If RSOO is supplied, the server MAY use its content to double check
whether a Reconfigure is required to be sent to the client. This whether a Reconfigure is required to be sent to the client. This
assumes the server store the content of RSOO it used to generate assumes the server store the content of RSOO it used to generate
configuration data sent to requesting clients. configuration data sent to requesting clients.
Then, the server MUST follow the procedure defined in Section 19.1 of Then, the server MUST follow the procedure defined in Section 19.1 of
[RFC3315] to construct a Reconfigure message. This message may be [RFC3315] to construct a Reconfigure message. This message may be
sent directly to the DHCPv6 client or to a relay agent [RFC3315]. sent directly to the DHCPv6 client or to a relay agent [RFC3315].
4. IANA Considerations 5. IANA Considerations
This document requests IANA to assign a new DHCPv6 Message type: IANA is requested to assign the following new DHCPv6 Message type in
the registry maintained in
http://www.iana.org/assignments/dhcpv6-parameters:
RECONFIGURE-REQUEST RECONFIGURE-REQUEST
5. Security Considerations IANA is requested to assign the following new DHCPv6 Option Codes in
the registry maintained in
http://www.iana.org/assignments/dhcpv6-parameters:
OPTION_LINK_ADDRESS
6. Security Considerations
Security considerations elaborated in [RFC3315] and [RFC6422] must be Security considerations elaborated in [RFC3315] and [RFC6422] must be
taken into account. In addition, DHCPv6 servers MAY be configured to taken into account. In addition, DHCPv6 servers MAY be configured to
discard relayed RECONFIGURE-REQUEST messages or restrict relay discard relayed RECONFIGURE-REQUEST messages or restrict relay
chaining (see [RFC5007] for more discussion about the rationale of chaining (see [RFC5007] for more discussion about the rationale of
this recommended behavior). Relay agents SHOULD implement this recommended behavior). Relay agents SHOULD implement
appropriate means to prevent using RECONFIGURE-REQUEST messages as a appropriate means to prevent using RECONFIGURE-REQUEST messages as a
denial-of-service attack on the DHCPv6 servers. denial-of-service attack on the DHCPv6 servers.
6. Acknowledgements 7. Acknowledgements
Many thanks to T. Lemon, R. Maglione, A. Kostur, G. Halwasia and C. Many thanks to R. Maglione, A. Kostur, G. Halwasia, C. Jacquenet and
Jacquenet for the comments and review. B. Volz for the comments and review.
7. References Special thanks to T. Lemon who provided a detailed review.
7.1. Normative References
8. References
8.1. Normative References
[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, March 1997.
[RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., [RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C.,
and M. Carney, "Dynamic Host Configuration Protocol for and M. Carney, "Dynamic Host Configuration Protocol for
IPv6 (DHCPv6)", RFC 3315, July 2003. IPv6 (DHCPv6)", RFC 3315, July 2003.
[RFC6422] Lemon, T. and Q. Wu, "Relay-Supplied DHCP Options", [RFC6422] Lemon, T. and Q. Wu, "Relay-Supplied DHCP Options",
RFC 6422, December 2011. RFC 6422, December 2011.
7.2. Informative References 8.2. Informative References
[RFC5007] Brzozowski, J., Kinnear, K., Volz, B., and S. Zeng, [RFC5007] Brzozowski, J., Kinnear, K., Volz, B., and S. Zeng,
"DHCPv6 Leasequery", RFC 5007, September 2007. "DHCPv6 Leasequery", RFC 5007, September 2007.
[RFC5176] Chiba, M., Dommety, G., Eklund, M., Mitton, D., and B. [RFC5176] Chiba, M., Dommety, G., Eklund, M., Mitton, D., and B.
Aboba, "Dynamic Authorization Extensions to Remote Aboba, "Dynamic Authorization Extensions to Remote
Authentication Dial In User Service (RADIUS)", RFC 5176, Authentication Dial In User Service (RADIUS)", RFC 5176,
January 2008. January 2008.
Authors' Addresses Authors' Addresses
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