draft-ietf-6man-addr-select-opt-03.txt		draft-ietf-6man-addr-select-opt-04.txt
	6man Working Group A. Matsumoto		6man Working Group A. Matsumoto
	Internet-Draft T. Fujisaki		Internet-Draft T. Fujisaki
	Intended status: Standards Track J. Kato		Intended status: Standards Track J. Kato
	Expires: August 24, 2012 NTT		Expires: January 17, 2013 NTT
	T. Chown		T. Chown
	University of Southampton		University of Southampton
	February 21, 2012		July 16, 2012
	Distributing Address Selection Policy using DHCPv6		Distributing Address Selection Policy using DHCPv6
	draft-ietf-6man-addr-select-opt-03.txt		draft-ietf-6man-addr-select-opt-04.txt
	Abstract		Abstract
	RFC 3484 defines default address selection mechanisms for IPv6 that		RFC 3484 defines default address selection mechanisms for IPv6 that
	allow nodes to select appropriate address when faced with multiple		allow nodes to select appropriate address when faced with multiple
	source and/or destination addresses to choose between. The RFC 3484		source and/or destination addresses to choose between. The RFC 3484
	allowed for the future definition of methods to administratively		allowed for the future definition of methods to administratively
	configure the address selection policy information. This document		configure the address selection policy information. This document
	defines a new DHCPv6 option for such configuration, allowing a site		defines a new DHCPv6 option for such configuration, allowing a site
	administrator to distribute address selection policy overriding the		administrator to distribute address selection policy overriding the
	default address selection policy table, and thus control the address		default address selection parameters and policy table, and thus
	selection behavior of nodes in their site.		control the address selection behavior of nodes in their site.
	Status of this Memo		Status of this Memo
	This Internet-Draft is submitted in full conformance with the		This Internet-Draft is submitted in full conformance with the
	provisions of BCP 78 and BCP 79.		provisions of BCP 78 and BCP 79.
	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 August 24, 2012.		This Internet-Draft will expire on January 17, 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
	skipping to change at page 2, line 42		skipping to change at page 2, line 42
	configuration.		configuration.
	Some problems have been identified with the default RFC 3484 address		Some problems have been identified with the default RFC 3484 address
	selection policy [RFC5220]. It is unlikely that any default policy		selection policy [RFC5220]. It is unlikely that any default policy
	will suit all scenarios, and thus mechanisms to control the source		will suit all scenarios, and thus mechanisms to control the source
	address selection policy will be necessary. Requirements for those		address selection policy will be necessary. Requirements for those
	mechanisms are described in [RFC5221], while solutions are discussed		mechanisms are described in [RFC5221], while solutions are discussed
	in [I-D.ietf-6man-addr-select-sol] and		in [I-D.ietf-6man-addr-select-sol] and
	[I-D.ietf-6man-addr-select-considerations]. Those documents have		[I-D.ietf-6man-addr-select-considerations]. Those documents have
	helped shape the improvements in the default address selection		helped shape the improvements in the default address selection
	algorithm [I-D.ietf-6man-rfc3484-revise] as well as the DHCPv6 option		algorithm [I-D.ietf-6man-rfc3484bis] as well as the DHCPv6 option
	defined in this specification.		defined in this specification.
	1.1. Conventions Used in This Document		1.1. Conventions Used in This Document
	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 [RFC2119].		document are to be interpreted as described in [RFC2119].
	1.2. Terminology		1.2. Terminology
	This document uses the terminology defined in [RFC2460] and the		This document uses the terminology defined in [RFC2460] and the
	DHCPv6 specification defined in [RFC3315]		DHCPv6 specification defined in [RFC3315]
	2. Address Selection Policy option		2. Address Selection options
	The Address Selection Policy option provides the policy table for		The Address Selection option provides the address selection policy
	address selection rules as described in RFC 3484 and in		table, and some other configuration parameters.
	[I-D.ietf-6man-rfc3484-revise].
	Each end node is expected to configure its policy table, as described		A address selection option contains zero or more policy table
	in RFC 3484, using the Address Selection Policy option as described		options. Multiple policy table options in a Policy Table option
	in the section below on processing the option.		constitute a single policy table.
	Multiple Address Selection Policy options MAY appear in a DHCPv6		The format of the Address Selection option is given below.
	message. They constitute a single policy table.
	The format of the Address Selection Policy option is given below.		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_ADDRSEL | option-len |
			+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
			| Reserved |A|P| |
			+-+-+-+-+-+-+-+-+ POLICY TABLE OPTIONS |
			| (variable length) |
			| |
			+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
			Figure 1: Address Selection option format
			option-code: OPTION_ADDRSEL (TBD).
			option-len: The total length of the Reserved field, A, P flags, and
			POLICY TABLE OPITONS in octets.
			Reserved: Reserved field. Server MUST set this value to zero and
			client MUST ignore its content.
			A: Automatic Row Addition flag. This flag toggles the Automatic
			Row Addition flag at client hosts, which is described in the
			section 2.1 in RFC 3484 revision [I-D.ietf-6man-rfc3484bis]. If
			this flag is set to 1, it does not change client host behavior,
			that is, a client MAY automatically add additional site-specific
			rows to the policy table. If set to 0, the Automatic Row
			Addition flag is disabled, and a client MAY NOT automatically
			add rows to the policy table.
			P: Privacy Preference flag. This flag toggles the Privacy
			Preference flag at client hosts, which is described in the
			section 5 in RFC 3484 revision [I-D.ietf-6man-rfc3484bis]. If
			this flag is set to 1, it does not change client host behavior,
			that is, a client SHOULD prefer temporary addresses. If set to
			0, the Privacy Preference flag is disabled, and a client SHOULD
			prefer public addresses.
			POLICY TABLE OPTIONS: Zero or more Address Selection Policy Table
			options described below.
	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
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| OPTION_DASP | option-len |		| OPTION_ADDRSEL_TABLE | option-len |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| label | precedence | prefix-len | |		| label | precedence | prefix-len | |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
	| |		| |
	| prefix (variable length) |		| prefix (variable length) |
	| |		| |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| |		| |
	. DASP options .		. Prefix Specific options .
	. .		. .
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	Figure 1: Address Selection Policy option format		Figure 2: Address Selection Policy Table option format
	option-code: OPTION_DASP (TBD).		option-code: OPTION_ADDRSEL_TABLE (TBD).
	option-len: The total length of the label field, precedence field,		option-len: The total length of the label field, precedence field,
	prefix-len field, prefix field, and DASP options field in		prefix-len field, prefix field, and DASP options field in
	octets.		octets.
	label: An 8-bit unsigned integer; this value is used to make a		label: An 8-bit unsigned integer; this value is used to make a
	combination of source address prefixes and destination address		combination of source address prefixes and destination address
	prefixes.		prefixes.
	precedence: An 8-bit unsigned integer; this value is used for		precedence: An 8-bit unsigned integer; this value is used for
	skipping to change at page 4, line 21		skipping to change at page 5, line 14
	prefix-len: An 8-bit unsigned integer; the number of leading bits in		prefix-len: An 8-bit unsigned integer; the number of leading bits in
	the prefix that are valid. The value ranges from 0 to 128.		the prefix that are valid. The value ranges from 0 to 128.
	prefix: A variable-length field containing an IP address or the		prefix: A variable-length field containing an IP address or the
	prefix of an IP address. An IPv4-mapped address [RFC4291] must		prefix of an IP address. An IPv4-mapped address [RFC4291] must
	be used to represent an IPv4 address as a prefix value. The		be used to represent an IPv4 address as a prefix value. The
	Prefix should be truncated on the byte boundary. So the length		Prefix should be truncated on the byte boundary. So the length
	of this field should be between 0 and 16 bytes.		of this field should be between 0 and 16 bytes.
	DASP options: Options specific to this particular Address Selection		Prefix Specific options: Options specific to this particular Address
	Policy option. This includes, but not limited to, zero or one		Selection Policy option. This includes, but not limited to,
	PREFIX_ZONE option that specify the zone index of the prefix in		zero or one Zone Index option that specify the zone index of the
	this option.		prefix in this option.
	The format of the Zone Index option is given below.		The format of the Zone Index option is given below.
	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
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| OPTION_ZONE_INDEX | option-len |		| OPTION_ADDRSEL_ZONE | option-len |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| zone-index |		| zone-index |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	Figure 2: Zone Index option format		Figure 3: Zone Index option format
	option-code: OPTION_ZONE_INDEX (TBD).		option-code: OPTION_ADDRSEL_ZONE (TBD).
	option-len: 4.		option-len: 4.
	zone-index: The zone-index field is an 32-bit unsigned integer, and		zone-index: The zone-index field is an 32-bit unsigned integer, and
	used to specify the zone for scoped addresses. The zone-index		used to specify the zone for scoped addresses. The zone-index
	is defined in RFC 3493 [RFC3493] as 'scope ID'.		is defined in RFC 3493 [RFC3493] as 'scope ID'.
	3. Appearance of the Address Selection Policy option		3. Appearance of the Address Selection options
	The Address Selection Policy option MUST NOT appear in any messages
	other than the following ones: Solicit, Advertise, Request, Renew,
	Rebind, Reconfigure, Information-Request, and Reply.
	4. Processing the Address Selection Policy option		The Address Selection options MUST NOT appear in any messages other
			than the following ones: Solicit, Advertise, Request, Renew, Rebind,
			Reconfigure, Information-Request, and Reply.
	This section describes how to process received Address Selection		4. Processing the Policy Table option
	Policy options at the DHCPv6 client.
	When a host receives a DHCPv6 message that includes multiple Address		This section describes how to process received Policy Table option at
	Selection Policy options, they MUST be treated as a single policy		the DHCPv6 client.
	table.
	This option's concept is to serve as a hint for a node about how to		This option's concept is to serve as a hint for a node about how to
	behave in the network. So, basically, it should be up to the node's		behave in the network. So, basically, it should be up to the node's
	administrator how to make use of or even ignore the received policy		administrator how to deal with the received policy information in the
	information.		way described below.
	4.1. Handling of the local policy table		4.1. Handling of the local policy table
	RFC 3484 defines the default policy table. Also, a user is usually		RFC 3484 defines the default policy table. Also, a user is usually
	able to configure the policy table to satisfy his requirement.		able to configure the policy table to satisfy his requirement.
	The client node SHOULD provide the following choices:		The client implementation SHOULD provide the following choices to the
			user:
	a) It receives distributed policy table, and replaces the existing		a) It receives distributed policy table, and replaces the existing
	policy tables with that.		policy tables with that.
	b) It preserves the default policy table, or manually configured		b) It preserves the default policy table, or manually configured
	policy.		policy.
	4.2. Handling of the stale policy table		4.2. Handling of the stale policy table
	When the information from the DHCP server goes stale, the policy		When the information from the DHCP server goes stale, the policy
	received form the DHCP server should be removed and the default		received form the DHCP server should be removed and the default
	policy should be restored.		policy should be restored.
	The received information can be considered stale in several cases,		The received information can be considered stale in several cases,
	such as, when the interface goes down, the DHCP server does not		such as, when the interface goes down, the DHCP server does not
	respond for a certain amount of time, and the Information Refresh		respond for a certain amount of time, and the Information Refresh
	Time is expired.		Time is expired.
	4.3. Processing multiple received policy tables		4.3. Processing multiple received policies
	The policy table is node-global information by its nature. So, the		The policy table, and other parameters specified in this document are
	node cannot use multiple received policy tables at the same time. In		node-global information by its nature. So, the node cannot use
	other words, once the received policy from one source is merged with		multiple received policies at the same time. In other words, once
	another source, the policy is more or less changed. The policy table		the received policy from one source is merged with another source,
	is defined as a whole, so the slightest addition/deletion from the		the policy is more or less changed. The policy table is defined as a
	policy table brings a change in semantics of the policy.		whole, so the slightest addition/deletion from the policy table
			brings a change in semantics of the policy.
	It also should be noted that, when a node is single-homed and has		It also should be noted that, when a node is single-homed and has
	only one upstream line, adopting a received policy table does not		only one upstream line, adopting a received policy table does not
	degrade the security level.		degrade the security level.
	Under the above assumptions, we specify how to handle multiple		Under the above assumptions, how to handle multiple received policies
	received policy tables below.		is specified below.
	A node MAY use OPTION_DASP in any of the following two cases:		A node MAY use Address Selection options in any of the following two
			cases:
	1: The address selection option is delivered across the only secure,		1: The Address Selection option is delivered across the only secure,
	trusted channel.		trusted channel.
	2: The address selection option delivery is not secured, but the node		2: The Address Selection option delivery is not secured, but the node
	is single-homed.		is single-homed.
	In other cases the node MUST NOT use OPTION_DASP unless the node is		In other cases the node MUST NOT use Policy Table options unless the
	specifically configured to do so.		node is specifically configured to do so.
			Discussion: The secure trusted channel does not necessarily mean a
			prioritized route in the routing table. So, such a situation
			could happen that the traffic goes through a non-secure, non-
			trusted channel and the host follows the delivered policy from a
			secure, truested channel. However, this policy is not for
			optimization of traffic and resources at the local network and the
			hosts, but for implementing the network policy to the hosts in the
			network.
	5. Implementation Considerations		5. Implementation Considerations
	o The value 'label' is passed as an unsigned integer, but there is		o The value 'label' is passed as an unsigned integer, but there is
	no special meaning for the value, that is whether it is a large or		no special meaning for the value, that is whether it is a large or
	small number. It is used to select a preferred source address		small number. It is used to select a preferred source address
	prefix corresponding to a destination address prefix by matching		prefix corresponding to a destination address prefix by matching
	the same label value within the DHCP message. DHCPv6 clients need		the same label value within the DHCP message. DHCPv6 clients need
	to convert this label to a representation specified by each		to convert this label to a representation specified by each
	implementation (e.g., string).		implementation (e.g., string).
	skipping to change at page 7, line 26		skipping to change at page 8, line 26
	Another threat is about privacy concern. As in the security		Another threat is about privacy concern. As in the security
	consideration section of RFC 3484, at least a part of, the address		consideration section of RFC 3484, at least a part of, the address
	selection policy stored in a host can be leaked by a packet from a		selection policy stored in a host can be leaked by a packet from a
	remote host. This issue will not be degraded regardless of the		remote host. This issue will not be degraded regardless of the
	introduction of this option, or regardless of whether the host is		introduction of this option, or regardless of whether the host is
	multihomed or not.		multihomed or not.
	7. IANA Considerations		7. IANA Considerations
	IANA is requested to assign option codes to OPTION_DASP from the		IANA is requested to assign option codes to OPTION_ADDRSEL ,
	option-code space as defined in section "DHCPv6 Options" of RFC 3315.		OPTION_ADDRSEL_TABLE, and OPTION_ADDRSEL_ZONE from the option-code
			space as defined in section "DHCPv6 Options" of RFC 3315.
	8. References		8. References
	8.1. Normative References		8.1. Normative References
			[I-D.ietf-6man-rfc3484bis]
			Thaler, D., Draves, R., Matsumoto, A., and T. Chown,
			"Default Address Selection for Internet Protocol version 6
			(IPv6)", draft-ietf-6man-rfc3484bis-06 (work in progress),
			June 2012.
			[I-D.ietf-6man-stable-privacy-addresses]
			Gont, F., "A method for Generating Stable Privacy-Enhanced
			Addresses with IPv6 Stateless Address Autoconfiguration
			(SLAAC)", draft-ietf-6man-stable-privacy-addresses-00
			(work in progress), May 2012.
	[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.
	[RFC3484] Draves, R., "Default Address Selection for Internet		[RFC3484] Draves, R., "Default Address Selection for Internet
	Protocol version 6 (IPv6)", RFC 3484, February 2003.		Protocol version 6 (IPv6)", RFC 3484, February 2003.
	skipping to change at page 8, line 11		skipping to change at page 9, line 23
	Address Selection Policy Changes",		Address Selection Policy Changes",
	draft-ietf-6man-addr-select-considerations-04 (work in		draft-ietf-6man-addr-select-considerations-04 (work in
	progress), October 2011.		progress), October 2011.
	[I-D.ietf-6man-addr-select-sol]		[I-D.ietf-6man-addr-select-sol]
	Matsumoto, A., Fujisaki, T., and R. Hiromi, "Solution		Matsumoto, A., Fujisaki, T., and R. Hiromi, "Solution
	approaches for address-selection problems",		approaches for address-selection problems",
	draft-ietf-6man-addr-select-sol-03 (work in progress),		draft-ietf-6man-addr-select-sol-03 (work in progress),
	March 2010.		March 2010.
	[I-D.ietf-6man-rfc3484-revise]
	Matsumoto, A., Kato, J., Fujisaki, T., and T. Chown,
	"Update to RFC 3484 Default Address Selection for IPv6",
	draft-ietf-6man-rfc3484-revise-05 (work in progress),
	October 2011.
	[RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6		[RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6
	(IPv6) Specification", RFC 2460, December 1998.		(IPv6) Specification", RFC 2460, December 1998.
	[RFC3493] Gilligan, R., Thomson, S., Bound, J., McCann, J., and W.		[RFC3493] Gilligan, R., Thomson, S., Bound, J., McCann, J., and W.
	Stevens, "Basic Socket Interface Extensions for IPv6",		Stevens, "Basic Socket Interface Extensions for IPv6",
	RFC 3493, February 2003.		RFC 3493, February 2003.
	[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, February 2006.
End of changes. 35 change blocks.
	64 lines changed or deleted		116 lines changed or added
This html diff was produced by rfcdiff 1.41. The latest version is available from http://tools.ietf.org/tools/rfcdiff/