Internet DRAFT - draft-cui-dhc-dhcp4o6-bulk-active-leasequery
draft-cui-dhc-dhcp4o6-bulk-active-leasequery
dhc Working Group Y. Cui
Internet-Draft Z. Liu
Intended status: Informational C. Liu
Expires: September 10, 2015 Tsinghua University
Y. Lee
Comcast
March 9, 2015
DHCP4o6 Bulk and Active Leasequery
draft-cui-dhc-dhcp4o6-bulk-active-leasequery-01
Abstract
As networks migrate towards IPv6, some entities still have the
requirement for IPv4 configuration. DHCPv4 over DHCPv6 [RFC7341]
provides a mechanism for obtaining IPv4 configuration information
dynamically in IPv6 networks. DHCPv4/DHCPv6 Bulk Leasequery and
Active Leasequery allow a client to get DHCP address binding
information data in bulk transfer or in real-time via TCP. This
document describes an extension of DHCPv6 Bulk and Active Leasequery
that provides a mechanism to get DHCPv4 over DHCPv6 lease
information.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 10, 2015.
Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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(http://trustee.ietf.org/license-info) in effect on the date of
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 3
4. Message and Option Description . . . . . . . . . . . . . . . 4
5. Requestor and Server Behavior . . . . . . . . . . . . . . . . 5
5.1. Extension to Bulk Leasequery . . . . . . . . . . . . . . 5
5.2. Extension to Active Leasequery . . . . . . . . . . . . . 6
6. Security Considerations . . . . . . . . . . . . . . . . . . . 7
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
7.1. Normative References . . . . . . . . . . . . . . . . . . 7
7.2. Informative References . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
The DHCPv4 Leasequery [RFC4388] extends the basic DHCPv4 capability
[RFC2131] [RFC2132]to allow a requestor to query a DHCPv4 server for
an individual binding information. DHCPv4 Bulk Leasequery[RFC6926]
extends [RFC4388] to allow a requestor to query a DHCPv4 server for
bulk transfer of binding information. DHCPv4 Active Leasequery
further extends [RFC6926] to create a long-lived TCP connection
between the requester and DHCPv4 server for near real-time binding
information. Paralle Leasequery protocols are also defined for
DHCPv6.
In IPv6 migration, some hosts in IPv6 network may also need DHCPv4
configuration using DHCPv4 over DHCPv6[RFC7341]. In some use cases,
it also need to extend DHCPv4 over DHCPv6 to carry related IPv6
information along with the DHCPv4 configuration, such as
[I-D.fsc-softwire-dhcp4o6-saddr-opt]. In these extending DHCPv4 over
DHCPv6 messages, IPv4 and IPv6 bindings may interact and correlate
with each other. The DHCPv4 lease information (including IPv4
address and other DHCPv4 options) is encapsulated in DHCPv4 Message
option as defined in[RFC7341]. And the related IPv6 bindings is
encapsulated in DHCPv6 message (DHCPV4-QUERY/DHCPV4-RESPONSE
messages).
The interaction of the DHCPv4 and IPv6 information used by DHCP4o6
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makes it different from original DHCPv4 [RFC2131]. One example is
Lightweight 4over6 dynamic provisioning: A client (lwB4) may use
DHCPv6 option(OPTION_DHCP4O6_SADDR)
[I-D.fsc-softwire-dhcp4o6-saddr-opt] to set the IPv6 tunnel source
address in the DHCP4o6 server. For each lwB4, the lwAFTR needs to
create a mapping entry. The mapping contains the tuple (lease IPv4
address, port set, IPv6 tunnel source address). The lwAFTR must
obtain the tuple before providing service to a particular lwB4.
However, there is no single DHCP server contains all three pieces of
information.
The lwB4's IPv6 tunnel source address may be an active IPv6 address
lease or a manual static address. The OPTION_DHCP4O6_SADDR is a
DHCPv6 option but may not bind to the active IPv6 address lease.
Furthermore, DHCP4o6 message doesn't contain DUID or any kind of
identifiers for the requestor to query the DHCPv4 lease and co-relate
it to the IPv6 configuration. In this scenario, the requestor
(lwAFTR) cannot get the lwB4s' IPv6 tunnel source address using
DHCPv4 Bulk/Active Leasequery or DHCPv6 Bulk/Active Leasequery.
DHCPv4 Bulk/Active Leasequery is DHCPv4 protocol, they can't be used
to query DHCPv6 bindings. Similarly, DHCPv6 Bulk/Active Leasequery
is DHCPv6 protocol, it can't be used to query DHCPv4 bindings. This
document describes an extension of DHCPv6 Bulk and Active Leasequery
to allow a requestor to request DHCPv4 lease and related IPv6
configuration.
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
3. Protocol Overview
In IPv6 network, entities use DHCPv4 over DHCPv6 to get DHCPv4
configuration and even get the related IPv6 configuration just like
the OPTION_DHCP4O6_SADDR defined in
[I-D.fsc-softwire-dhcp4o6-saddr-opt]. Entities may need other
related IPv6 configuration along with DHCPv4 lease using DHCPv4 over
DHCPv6. DHCP4o6 Bulk/Active Leasequery mechanism based on both
DHCPv4/DHCPv6 Bulk Leasequery and DHCPv4/DHCPv6 Active Leasequery
make requestor get DHCP4o6 lease information (DHCPv4 lease and
related IPv6 configuration) in bulk transfer or in real-time from
DHCP4o6 server via TCP.
The DHCP4o6 Bulk/Active Leasequery mechanism is modeled on the
existing DHCPv4 over DHCPv6 protocol in[RFC7341], which combines
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DHCPv4 Bulk/Active Leasequery and DHCPv6 Bulk/Active Leasequery to
provide DHCPv4 lease and related IPv6 information in IPv6 network.
The DHCP4o6 Bulk/Active Leasequery requestors and DHCP4o6 servers
communicate with each other using DHCPv6 Bulk/Active Leasequery which
contains DHCPv4 Message Option defined in [RFC7341]. In DHCPv6 Bulk/
Active Leasequery messages, DHCPv4 Message Option contains the DHCPv4
Bulk/Active leasequery message. The type and status of DHCPv4 Bulk/
Active leasequery message in the option should be synchronous with
the DHCPv6 part in the same message during the process of leasequery.
Requestor sends a DHCPv6 Bulk/Active Leasequery message contains
DHCPv4 Message Option to query for DHCP4o6 lease information. In the
message, the DHCPv4 lease query is put in the DHCPv4 Bulk/Active
Leasequery message in DHCPv4 Message Option, and related IPv6
configuration is put in the DHCPv6 option.
The DHCPv4 lease in the DHCPv4 Message Option of the messages sent by
DHCP4o6 server in response should be identical to the messages sent
by the DHCPv4 Bulk/Active Leasequery server. The related IPv6
configuration part in response is put in the DHCPv6 Bulk/Active
Leasequery options.
Applications which employ Active Leasequery to keep a database up to
date with respect to the server's lease state database usually use an
initial Bulk Leasequery to bring their database into equivalence with
that of the server. In DHCP4o6 Bulk and Active Leasequery, it works
in the same way.
4. Message and Option Description
All of the message types and options defined in DHCPv4/DHCPv6 Bulk/
Active Leasequery [RFC5460][I-D.ietf-dhc-dhcpv6-active-leasequery]
[RFC6926][I-D.ietf-dhc-dhcpv4-active-leasequery] are also used by
DHCP4o6 Bulk/Active Leasequery. In addition, a new usage of the
existing option is defined in this document. DHCPv4 Message Option
defined in [RFC7341] contains the DHCPv4 message sent by the DHCP
client or server. In DHCP4o6 Bulk/Active Leasequery scenario, DHCPv4
Message Option contains the DHCPv4 Bulk/Active Leasequery message
sent by requestor and DHCP4o6 server.
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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-code | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. DHCPv4-Bulk/Active-Leasequery-message .
. .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
option-code: OPTION_DHCPV4_MSG (87)
option-len: Length of the DHCPv4 Bulk/Active Leasequery message.
DHCPv4-Bulk/Active-Leasequery-message:
The DHCPv4 Bulk or Active Leasequery message sent by the client
or the server.
Figure 1: DHCPv4 Message Option
When using in DHCP4o6 Bulk Leasequery, DHCPv4 Message Option contains
DHCPv4 Bulk Leasequery message. When DHCP4o6 Bulk Leasequery
requestors query for DHCP4o6 lease information, DHCPv4 Message Option
contains the DHCPv4 DHCPBULKLEASEQUERY message. In response, DHCP4o6
servers will put the DHCPv4 reply message (DHCPLEASEACTIVE ,
DHCPLEASEUNASSIGNED or DHCPLEASEQUERYDONE message) in the DHCPv4
Message Option.
When using in DHCP4o6 Active Leasequery, DHCPv4 Message Option
contains DHCPv4 Active Leasequery message. When DHCP4o6 Active
Leasequery requestors query for DHCP4o6 lease information, DHCPv4
Message Option contains the DHCPv4 ACTIVELEASEQUERY message. In
response, DHCP4o6 servers will put the DHCPv4 reply message
(DHCPLEASEQUERYSTATUS, DHCPLEASEACTIVE , DHCPLEASEUNASSIGNED or
DHCPLEASEQUERYDONE message) in the DHCPv4 Message Option.
5. Requestor and Server Behavior
5.1. Extension to Bulk Leasequery
DHCP4o6 Bulk Leasequery extends the Bulk Leasequery to allow a
requestor getting bulk of DHCP4o6 lease information. A requestor
attempts to establish a TCP connection to a DHCP4o6 server in order
to initiate a leasequery exchange. If the attempt fails, the
requestor MAY retry.
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After a connection is established, the requestor constructs a DHCP4o6
Bulk Leasequery message. In DHCPv6 LEASEQUERY message, the Query
options MUST include an OPTION_ORO option to indicate the options for
each client's related IPv6 configuration that the requestor would
like the server to return. The query-type in Query option MUST be
identical with the query-type of the DHCPv4 Bulk Leasequery message
in DHCPv4 Message Option. Related IPv6 configuration is binding to
the DHCPv4 lease, and DHCPv4 DHCPBULKLEASEQUERY message in the DHCPv4
Message Option formats as defined in [RFC6926].
When DHCP4o6 server receives the extending DHCPv6 Bulk Leasequery
message, it first addresses the DHCPv4 Bulk Leasequery message as
defined in [RFC6926]. Then DHCP4o6 server addresses related IPv6
configuration query recording to the DHCPv4 replying. In LEASEQUERY-
REPLY, LEASEQUERY-DATA or LEASEQUERY-DONE message, DHCPv4 Message
Option contains the DHCPLEASEACTIVE , DHCPLEASEUNASSIGNED or
DHCPLEASEQUERYDONE message as a reply to DHCPv4 lease query and
Client Data Option contains the related IPv6 option as a reply to
related IPv6 configuration query. The status description in DHCPv6
reply message MUST be identical with the status in DHCPv4 reply
message in semantics.
5.2. Extension to Active Leasequery
DHCP4o6 Active Leasequery extends the Active Leasequery to allow a
requestor getting the current DHCP4o6 lease information and in this
scenario, DHCP4o6 server MUST support the DHCP4o6 Bulk Leasequery.
As defined in[I-D.ietf-dhc-dhcpv6-active-leasequery], an Active
Leasequery requestor would typically use Bulk Leasequery to
initialize its database with all current data when that database
contains no binding information. In addition, requestors would use
Bulk Leasequery to recover missed information in the event that it
recover from the failure. It also works in DHCP4o6 Active
Leasequery.
A requestor attempts to establish a TCP connection to a DHCP4o6
server in order to initiate an Active Leasequery exchange. If the
attempt fails, the requestor MAY retry. After a connection is
established, the requestor constructs a DHCP4o6 Active Leasequery
message. In ACTIVELEASEQUERY message, the Query options MUST include
an OPTION_ORO option to indicate the options for each client's
related IPv6 configration that the requestor would like the server to
return. The query-type in Query option MUST be identical with the
query-type of the DHCPv4 Active Leasequery message in DHCPv4 Message
Option. Similar to Bulk Leasequery, the DHCPv4 Active Leasequery
message DHCPACTIVELEASEQUERY message in the DHCPv4 Message Option
composes as defined in [I-D.ietf-dhc-dhcpv4-active-leasequery].
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When DHCP4o6 server receives the extending Active Leasequery message,
it first addresses the DHCPv4 Active Leasequery message as defined
in[I-D.ietf-dhc-dhcpv4-active-leasequery]. Then DHCP4o6 server
addresses related IPv6 configuration query according to the DHCPv4
replying. The status description in DHCPv6 reply message MUST be
identical with the status in DHCPv4 reply message in semantics. When
the server updates DHCPv4 lease or related IPv6 information, it will
generate a response to requestors. In response, the server sends
updates of DHCPv4o6 lease information in the DHCPv6 LEASEQUERY-DATA
message. In LEASEQUERY-REPLY, LEASEQUERY-DATA or LEASEQUERY-DONE
message, DHCPv4 Message Option contains the DHCPLEASEACTIVE,
DHCPLEASEUNASSIGNED or DHCPLEASEQUERYDONE message as a reply to
DHCPv4 lease query and Client Data Option contains the related IPv6
option as a reply to related IPv6 configuration query.
6. Security Considerations
The "Security Considerations" section of [RFC5460] and
[I-D.ietf-dhc-dhcpv6-active-leasequery]details the threats to DHCPv6
Bulk Leasequery and Active Leasequery especially additional concerns
for the use of TCP. In this document, DHCPv4 leasequery messages are
encapsulated in the defined option. In order to bypass firewalls or
network authentication gateways, a malicious attacker may leverage
this feature to convey other messages using DHCPv6 leasequery
message.
It is possible for a rogue host to reply as a DHCP4o6 leasequery
requestor, which may get configuration of the network. Or there is a
rogue server to provide false lease, which may misdirect requestor.
Requestors and DHCP4o6 servers may use TLS or other authentication
methods to protect the leasequery process.
7. References
7.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2131] Droms, R., "Dynamic Host Configuration Protocol", RFC
2131, March 1997.
[RFC2132] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor
Extensions", RFC 2132, March 1997.
[RFC4388] Woundy, R. and K. Kinnear, "Dynamic Host Configuration
Protocol (DHCP) Leasequery", RFC 4388, February 2006.
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[RFC5007] Brzozowski, J., Kinnear, K., Volz, B., and S. Zeng,
"DHCPv6 Leasequery", RFC 5007, September 2007.
[RFC5460] Stapp, M., "DHCPv6 Bulk Leasequery", RFC 5460, February
2009.
[RFC6926] Kinnear, K., Stapp, M., Desetti, R., Joshi, B., Russell,
N., Kurapati, P., and B. Volz, "DHCPv4 Bulk Leasequery",
RFC 6926, April 2013.
[RFC7341] Sun, Q., Cui, Y., Siodelski, M., Krishnan, S., and I.
Farrer, "DHCPv4-over-DHCPv6 (DHCP 4o6) Transport", RFC
7341, August 2014.
7.2. Informative References
[I-D.fsc-softwire-dhcp4o6-saddr-opt]
Farrer, I., Sun, Q., and Y. Cui, "DHCPv4 over DHCPv6
Source Address Option", draft-fsc-softwire-dhcp4o6-saddr-
opt-01 (work in progress), September 2014.
[I-D.ietf-dhc-dhcpv4-active-leasequery]
Kinnear, K., Stapp, M., Volz, B., and N. Russell, "Active
DHCPv4 Lease Query", draft-ietf-dhc-dhcpv4-active-
leasequery-02 (work in progress), March 2015.
[I-D.ietf-dhc-dhcpv6-active-leasequery]
Dushyant, D., Kinnear, K., and D. Kukrety, "DHCPv6 Active
Leasequery", draft-ietf-dhc-dhcpv6-active-leasequery-02
(work in progress), March 2015.
[I-D.ietf-dhc-dynamic-shared-v4allocation]
Cui, Y., Qiong, Q., Farrer, I., Lee, Y., Sun, Q., and M.
Boucadair, "Dynamic Allocation of Shared IPv4 Addresses",
draft-ietf-dhc-dynamic-shared-v4allocation-05 (work in
progress), February 2015.
[I-D.ietf-softwire-lw4over6]
Cui, Y., Qiong, Q., Boucadair, M., Tsou, T., Lee, Y., and
I. Farrer, "Lightweight 4over6: An Extension to the DS-
Lite Architecture", draft-ietf-softwire-lw4over6-13 (work
in progress), November 2014.
Authors' Addresses
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Yong Cui
Tsinghua University
Beijing 100084
P.R.China
Phone: +86-10-6260-3059
Email: yong@csnet1.cs.tsinghua.edu.cn
ZiLong Liu
Tsinghua University
Beijing 100084
P.R.China
Phone: +86-10-6278-5822
Email: liuzilong8266@163.com
Cong Liu
Tsinghua University
Beijing 100084
P.R.China
Phone: +86-10-6278-5822
Email: gnocuil@gmail.com
Yiu L. Lee
Comcast
U.S.A
Email: yiu_lee@cable.comcast.com
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