Internet Engineering Task Force (IETF) M. Bjorklund
Request for Comments: 7277 Tail-f Systems
Category: Standards Track June 2014
ISSN: 2070-1721
 A YANG Data Model for IP Management
Abstract
 This document defines a YANG data model for management of IP
 implementations. The data model includes configuration data and
 state data.
Status of This Memo
 This is an Internet Standards Track document.
 This document is a product of the Internet Engineering Task Force
 (IETF). It represents the consensus of the IETF community. It has
 received public review and has been approved for publication by the
 Internet Engineering Steering Group (IESG). Further information on
 Internet Standards is available in Section 2 of RFC 5741.
 Information about the current status of this document, any errata,
 and how to provide feedback on it may be obtained at
 http://www.rfc-editor.org/info/rfc7277.
Copyright Notice
 Copyright (c) 2014 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
 (http://trustee.ietf.org/license-info) in effect on the date of
 publication of this document. Please review these documents
 carefully, as they describe your rights and restrictions with respect
 to this document. Code Components extracted from this document must
 include Simplified BSD License text as described in Section 4.e of
 the Trust Legal Provisions and are provided without warranty as
 described in the Simplified BSD License.
Table of Contents
 1. Introduction ....................................................2
 1.1. Terminology ................................................2
 1.2. Tree Diagrams ..............................................3
 2. IP Data Model ...................................................3
 3. Relationship to the IP-MIB ......................................6
 4. IP Management YANG Module .......................................8
 5. IANA Considerations ............................................24
 6. Security Considerations ........................................24
 7. Acknowledgments ................................................25
 8. References .....................................................25
 8.1. Normative References ......................................25
 8.2. Informative References ....................................26
 Appendix A. Example: NETCONF <get> Reply ..........................28
1. Introduction
 This document defines a YANG [RFC6020] data model for management of
 IP implementations.
 The data model covers configuration of per-interface IPv4 and IPv6
 parameters, and mappings of IP addresses to link-layer addresses. It
 also provides information about which IP addresses are operationally
 used, and which link-layer mappings exist. Per-interface parameters
 are added through augmentation of the interface data model defined in
 [RFC7223].
1.1. Terminology
 The following terms are defined in [RFC6241] and are not redefined
 here:
 o client
 o configuration data
 o server
 o state data
 The following terms are defined in [RFC6020] and are not redefined
 here:
 o augment
 o data model
 o data node
 The terminology for describing YANG data models is found in
 [RFC6020].
1.2. Tree Diagrams
 A simplified graphical representation of the data model is used in
 this document. The meaning of the symbols in these diagrams is as
 follows:
 o Brackets "[" and "]" enclose list keys.
 o Abbreviations before data node names: "rw" means configuration
 data (read-write), and "ro" means state data (read-only).
 o Symbols after data node names: "?" means an optional node, "!"
 means a presence container, and "*" denotes a list and leaf-list.
 o Parentheses enclose choice and case nodes, and case nodes are also
 marked with a colon (":").
 o Ellipsis ("...") stands for contents of subtrees that are not
 shown.
2. IP Data Model
 This document defines the YANG module "ietf-ip", which augments the
 "interface" and "interface-state" lists defined in the
 "ietf-interfaces" module [RFC7223] with IP-specific data nodes, and
 also adds IP-specific state data.
 The data model has the following structure for IP configuration per
 interface:
 +--rw if:interfaces
 +--rw if:interface* [name]
 ...
 +--rw ipv4!
 | +--rw enabled? boolean
 | +--rw forwarding? boolean
 | +--rw mtu? uint16
 | +--rw address* [ip]
 | | +--rw ip inet:ipv4-address-no-zone
 | | +--rw (subnet)
 | | +--:(prefix-length)
 | | | +--rw ip:prefix-length? uint8
 | | +--:(netmask)
 | | +--rw ip:netmask? yang:dotted-quad
 | +--rw neighbor* [ip]
 | +--rw ip inet:ipv4-address-no-zone
 | +--rw link-layer-address yang:phys-address
 +--rw ipv6!
 +--rw enabled? boolean
 +--rw forwarding? boolean
 +--rw mtu? uint32
 +--rw address* [ip]
 | +--rw ip inet:ipv6-address-no-zone
 | +--rw prefix-length uint8
 +--rw neighbor* [ip]
 | +--rw ip inet:ipv6-address-no-zone
 | +--rw link-layer-address yang:phys-address
 +--rw dup-addr-detect-transmits? uint32
 +--rw autoconf
 +--rw create-global-addresses? boolean
 +--rw create-temporary-addresses? boolean
 +--rw temporary-valid-lifetime? uint32
 +--rw temporary-preferred-lifetime? uint32
 The data model defines two configuration containers per interface --
 "ipv4" and "ipv6", representing the IPv4 and IPv6 address families.
 In each container, there is a leaf "enabled" that controls whether or
 not the address family is enabled on that interface, and a leaf
 "forwarding" that controls whether or not IP packet forwarding for
 the address family is enabled on the interface. In each container,
 there is also a list of configured addresses, and a list of
 configured mappings from IP addresses to link-layer addresses.
 The data model has the following structure for IP state per
 interface:
 +--ro if:interfaces-state
 +--ro if:interface* [name]
 ...
 +--ro ipv4!
 | +--ro forwarding? boolean
 | +--ro mtu? uint16
 | +--ro address* [ip]
 | | +--ro ip inet:ipv4-address-no-zone
 | | +--ro (subnet)?
 | | | +--:(prefix-length)
 | | | | +--ro prefix-length? uint8
 | | | +--:(netmask)
 | | | +--ro netmask? yang:dotted-quad
 | | +--ro origin? ip-address-origin
 | +--ro neighbor* [ip]
 | +--ro ip inet:ipv4-address-no-zone
 | +--ro link-layer-address? yang:phys-address
 | +--ro origin? neighbor-origin
 +--ro ipv6!
 +--ro forwarding? boolean
 +--ro mtu? uint32
 +--ro address* [ip]
 | +--ro ip inet:ipv6-address-no-zone
 | +--ro prefix-length uint8
 | +--ro origin? ip-address-origin
 | +--ro status? enumeration
 +--ro neighbor* [ip]
 +--ro ip inet:ipv6-address-no-zone
 +--ro link-layer-address? yang:phys-address
 +--ro origin? neighbor-origin
 +--ro is-router? empty
 +--ro state? enumeration
 The data model defines two state containers per interface -- "ipv4"
 and "ipv6", representing the IPv4 and IPv6 address families. In each
 container, there is a leaf "forwarding" that indicates whether or not
 IP packet forwarding is enabled on that interface. In each
 container, there is also a list of all addresses in use and a list of
 known mappings from IP addresses to link-layer addresses.
3. Relationship to the IP-MIB
 If the device implements the IP-MIB [RFC4293], each entry in the
 "ipv4/address" and "ipv6/address" lists is mapped to one
 ipAddressEntry, where the ipAddressIfIndex refers to the "address"
 entry's interface.
 The IP-MIB defines objects to control IPv6 Router Advertisement
 messages. The corresponding YANG data nodes are defined in
 [ROUTING-MGMT].
 The entries in "ipv4/neighbor" and "ipv6/neighbor" are mapped to
 ipNetToPhysicalTable.
 The following tables list the YANG data nodes with corresponding
 objects in the IP-MIB.
 +----------------------------------+--------------------------------+
 | YANG data node in | IP-MIB object |
 | /if:interfaces/if:interface | |
 +----------------------------------+--------------------------------+
 | ipv4/enabled | ipv4InterfaceEnableStatus |
 | ipv4/address | ipAddressEntry |
 | ipv4/address/ip | ipAddressAddrType |
 | | ipAddressAddr |
 | ipv4/neighbor | ipNetToPhysicalEntry |
 | ipv4/neighbor/ip | ipNetToPhysicalNetAddressType |
 | | ipNetToPhysicalNetAddress |
 | ipv4/neighbor/link-layer-address | ipNetToPhysicalPhysAddress |
 | | |
 | ipv6/enabled | ipv6InterfaceEnableStatus |
 | ipv6/forwarding | ipv6InterfaceForwarding |
 | ipv6/address | ipAddressEntry |
 | ipv6/address/ip | ipAddressAddrType |
 | | ipAddressAddr |
 | ipv6/neighbor | ipNetToPhysicalEntry |
 | ipv6/neighbor/link-layer-address | ipNetToPhysicalPhysAddress |
 | ipv6/neighbor/origin | ipNetToPhysicalType |
 +----------------------------------+--------------------------------+
 YANG Interface Configuration Data Nodes and Related IP-MIB Objects
 +-----------------------------------+-------------------------------+
 | YANG data node in | IP-MIB object |
 | /if:interfaces-state/if:interface | |
 +-----------------------------------+-------------------------------+
 | ipv4 | ipv4InterfaceEnableStatus |
 | ipv4/address | ipAddressEntry |
 | ipv4/address/ip | ipAddressAddrType |
 | | ipAddressAddr |
 | ipv4/address/origin | ipAddressOrigin |
 | ipv4/neighbor | ipNetToPhysicalEntry |
 | ipv4/neighbor/ip | ipNetToPhysicalNetAddressType |
 | | ipNetToPhysicalNetAddress |
 | ipv4/neighbor/link-layer-address | ipNetToPhysicalPhysAddress |
 | ipv4/neighbor/origin | ipNetToPhysicalType |
 | | |
 | ipv6 | ipv6InterfaceEnableStatus |
 | ipv6/forwarding | ipv6InterfaceForwarding |
 | ipv6/address | ipAddressEntry |
 | ipv6/address/ip | ipAddressAddrType |
 | | ipAddressAddr |
 | ipv6/address/origin | ipAddressOrigin |
 | ipv6/address/status | ipAddressStatus |
 | ipv6/neighbor | ipNetToPhysicalEntry |
 | ipv6/neighbor/ip | ipNetToPhysicalNetAddressType |
 | | ipNetToPhysicalNetAddress |
 | ipv6/neighbor/link-layer-address | ipNetToPhysicalPhysAddress |
 | ipv6/neighbor/origin | ipNetToPhysicalType |
 | ipv6/neighbor/state | ipNetToPhysicalState |
 +-----------------------------------+-------------------------------+
 YANG Interface State Data Nodes and Related IP-MIB Objects
4. IP Management YANG Module
 This module imports typedefs from [RFC6991] and [RFC7223], and it
 references [RFC0791], [RFC0826], [RFC2460], [RFC4861], [RFC4862],
 [RFC4941], and [RFC7217].
 <CODE BEGINS> file "ietf-ip@2014年06月16日.yang"
 module ietf-ip {
 namespace "urn:ietf:params:xml:ns:yang:ietf-ip";
 prefix ip;
 import ietf-interfaces {
 prefix if;
 }
 import ietf-inet-types {
 prefix inet;
 }
 import ietf-yang-types {
 prefix yang;
 }
 organization
 "IETF NETMOD (NETCONF Data Modeling Language) Working Group";
 contact
 "WG Web: <http://tools.ietf.org/wg/netmod/>
 WG List: <mailto:netmod@ietf.org>
 WG Chair: Thomas Nadeau
 <mailto:tnadeau@lucidvision.com>
 WG Chair: Juergen Schoenwaelder
 <mailto:j.schoenwaelder@jacobs-university.de>
 Editor: Martin Bjorklund
 <mailto:mbj@tail-f.com>";
 description
 "This module contains a collection of YANG definitions for
 configuring IP implementations.
 Copyright (c) 2014 IETF Trust and the persons identified as
 authors of the code. All rights reserved.
 Redistribution and use in source and binary forms, with or
 without modification, is permitted pursuant to, and subject
 to the license terms contained in, the Simplified BSD License
 set forth in Section 4.c of the IETF Trust's Legal Provisions
 Relating to IETF Documents
 (http://trustee.ietf.org/license-info).
 This version of this YANG module is part of RFC 7277; see
 the RFC itself for full legal notices.";
 revision 2014年06月16日 {
 description
 "Initial revision.";
 reference
 "RFC 7277: A YANG Data Model for IP Management";
 }
 /*
 * Features
 */
 feature ipv4-non-contiguous-netmasks {
 description
 "Indicates support for configuring non-contiguous
 subnet masks.";
 }
 feature ipv6-privacy-autoconf {
 description
 "Indicates support for Privacy Extensions for Stateless Address
 Autoconfiguration in IPv6.";
 reference
 "RFC 4941: Privacy Extensions for Stateless Address
 Autoconfiguration in IPv6";
 }
 /*
 * Typedefs
 */
 typedef ip-address-origin {
 type enumeration {
 enum other {
 description
 "None of the following.";
 }
 enum static {
 description
 "Indicates that the address has been statically
 configured - for example, using NETCONF or a Command Line
 Interface.";
 }
 enum dhcp {
 description
 "Indicates an address that has been assigned to this
 system by a DHCP server.";
 }
 enum link-layer {
 description
 "Indicates an address created by IPv6 stateless
 autoconfiguration that embeds a link-layer address in its
 interface identifier.";
 }
 enum random {
 description
 "Indicates an address chosen by the system at
 random, e.g., an IPv4 address within 169.254/16, an
 RFC 4941 temporary address, or an RFC 7217 semantically
 opaque address.";
 reference
 "RFC 4941: Privacy Extensions for Stateless Address
 Autoconfiguration in IPv6
 RFC 7217: A Method for Generating Semantically Opaque
 Interface Identifiers with IPv6 Stateless
 Address Autoconfiguration (SLAAC)";
 }
 }
 description
 "The origin of an address.";
 }
 typedef neighbor-origin {
 type enumeration {
 enum other {
 description
 "None of the following.";
 }
 enum static {
 description
 "Indicates that the mapping has been statically
 configured - for example, using NETCONF or a Command Line
 Interface.";
 }
 enum dynamic {
 description
 "Indicates that the mapping has been dynamically resolved
 using, e.g., IPv4 ARP or the IPv6 Neighbor Discovery
 protocol.";
 }
 }
 description
 "The origin of a neighbor entry.";
 }
 /*
 * Configuration data nodes
 */
 augment "/if:interfaces/if:interface" {
 description
 "Parameters for configuring IP on interfaces.
 If an interface is not capable of running IP, the server
 must not allow the client to configure these parameters.";
 container ipv4 {
 presence
 "Enables IPv4 unless the 'enabled' leaf
 (which defaults to 'true') is set to 'false'";
 description
 "Parameters for the IPv4 address family.";
 leaf enabled {
 type boolean;
 default true;
 description
 "Controls whether IPv4 is enabled or disabled on this
 interface. When IPv4 is enabled, this interface is
 connected to an IPv4 stack, and the interface can send
 and receive IPv4 packets.";
 }
 leaf forwarding {
 type boolean;
 default false;
 description
 "Controls IPv4 packet forwarding of datagrams received by,
 but not addressed to, this interface. IPv4 routers
 forward datagrams. IPv4 hosts do not (except those
 source-routed via the host).";
 }
 leaf mtu {
 type uint16 {
 range "68..max";
 }
 units octets;
 description
 "The size, in octets, of the largest IPv4 packet that the
 interface will send and receive.
 The server may restrict the allowed values for this leaf,
 depending on the interface's type.
 If this leaf is not configured, the operationally used MTU
 depends on the interface's type.";
 reference
 "RFC 791: Internet Protocol";
 }
 list address {
 key "ip";
 description
 "The list of configured IPv4 addresses on the interface.";
 leaf ip {
 type inet:ipv4-address-no-zone;
 description
 "The IPv4 address on the interface.";
 }
 choice subnet {
 mandatory true;
 description
 "The subnet can be specified as a prefix-length, or,
 if the server supports non-contiguous netmasks, as
 a netmask.";
 leaf prefix-length {
 type uint8 {
 range "0..32";
 }
 description
 "The length of the subnet prefix.";
 }
 leaf netmask {
 if-feature ipv4-non-contiguous-netmasks;
 type yang:dotted-quad;
 description
 "The subnet specified as a netmask.";
 }
 }
 }
 list neighbor {
 key "ip";
 description
 "A list of mappings from IPv4 addresses to
 link-layer addresses.
 Entries in this list are used as static entries in the
 ARP Cache.";
 reference
 "RFC 826: An Ethernet Address Resolution Protocol";
 leaf ip {
 type inet:ipv4-address-no-zone;
 description
 "The IPv4 address of the neighbor node.";
 }
 leaf link-layer-address {
 type yang:phys-address;
 mandatory true;
 description
 "The link-layer address of the neighbor node.";
 }
 }
 }
 container ipv6 {
 presence
 "Enables IPv6 unless the 'enabled' leaf
 (which defaults to 'true') is set to 'false'";
 description
 "Parameters for the IPv6 address family.";
 leaf enabled {
 type boolean;
 default true;
 description
 "Controls whether IPv6 is enabled or disabled on this
 interface. When IPv6 is enabled, this interface is
 connected to an IPv6 stack, and the interface can send
 and receive IPv6 packets.";
 }
 leaf forwarding {
 type boolean;
 default false;
 description
 "Controls IPv6 packet forwarding of datagrams received by,
 but not addressed to, this interface. IPv6 routers
 forward datagrams. IPv6 hosts do not (except those
 source-routed via the host).";
 reference
 "RFC 4861: Neighbor Discovery for IP version 6 (IPv6)
 Section 6.2.1, IsRouter";
 }
 leaf mtu {
 type uint32 {
 range "1280..max";
 }
 units octets;
 description
 "The size, in octets, of the largest IPv6 packet that the
 interface will send and receive.
 The server may restrict the allowed values for this leaf,
 depending on the interface's type.
 If this leaf is not configured, the operationally used MTU
 depends on the interface's type.";
 reference
 "RFC 2460: Internet Protocol, Version 6 (IPv6) Specification
 Section 5";
 }
 list address {
 key "ip";
 description
 "The list of configured IPv6 addresses on the interface.";
 leaf ip {
 type inet:ipv6-address-no-zone;
 description
 "The IPv6 address on the interface.";
 }
 leaf prefix-length {
 type uint8 {
 range "0..128";
 }
 mandatory true;
 description
 "The length of the subnet prefix.";
 }
 }
 list neighbor {
 key "ip";
 description
 "A list of mappings from IPv6 addresses to
 link-layer addresses.
 Entries in this list are used as static entries in the
 Neighbor Cache.";
 reference
 "RFC 4861: Neighbor Discovery for IP version 6 (IPv6)";
 leaf ip {
 type inet:ipv6-address-no-zone;
 description
 "The IPv6 address of the neighbor node.";
 }
 leaf link-layer-address {
 type yang:phys-address;
 mandatory true;
 description
 "The link-layer address of the neighbor node.";
 }
 }
 leaf dup-addr-detect-transmits {
 type uint32;
 default 1;
 description
 "The number of consecutive Neighbor Solicitation messages
 sent while performing Duplicate Address Detection on a
 tentative address. A value of zero indicates that
 Duplicate Address Detection is not performed on
 tentative addresses. A value of one indicates a single
 transmission with no follow-up retransmissions.";
 reference
 "RFC 4862: IPv6 Stateless Address Autoconfiguration";
 }
 container autoconf {
 description
 "Parameters to control the autoconfiguration of IPv6
 addresses, as described in RFC 4862.";
 reference
 "RFC 4862: IPv6 Stateless Address Autoconfiguration";
 leaf create-global-addresses {
 type boolean;
 default true;
 description
 "If enabled, the host creates global addresses as
 described in RFC 4862.";
 reference
 "RFC 4862: IPv6 Stateless Address Autoconfiguration
 Section 5.5";
 }
 leaf create-temporary-addresses {
 if-feature ipv6-privacy-autoconf;
 type boolean;
 default false;
 description
 "If enabled, the host creates temporary addresses as
 described in RFC 4941.";
 reference
 "RFC 4941: Privacy Extensions for Stateless Address
 Autoconfiguration in IPv6";
 }
 leaf temporary-valid-lifetime {
 if-feature ipv6-privacy-autoconf;
 type uint32;
 units "seconds";
 default 604800;
 description
 "The time period during which the temporary address
 is valid.";
 reference
 "RFC 4941: Privacy Extensions for Stateless Address
 Autoconfiguration in IPv6
 - TEMP_VALID_LIFETIME";
 }
 leaf temporary-preferred-lifetime {
 if-feature ipv6-privacy-autoconf;
 type uint32;
 units "seconds";
 default 86400;
 description
 "The time period during which the temporary address is
 preferred.";
 reference
 "RFC 4941: Privacy Extensions for Stateless Address
 Autoconfiguration in IPv6
 - TEMP_PREFERRED_LIFETIME";
 }
 }
 }
 }
 /*
 * Operational state data nodes
 */
 augment "/if:interfaces-state/if:interface" {
 description
 "Data nodes for the operational state of IP on interfaces.";
 container ipv4 {
 presence "Present if IPv4 is enabled on this interface";
 config false;
 description
 "Interface-specific parameters for the IPv4 address family.";
 leaf forwarding {
 type boolean;
 description
 "Indicates whether IPv4 packet forwarding is enabled or
 disabled on this interface.";
 }
 leaf mtu {
 type uint16 {
 range "68..max";
 }
 units octets;
 description
 "The size, in octets, of the largest IPv4 packet that the
 interface will send and receive.";
 reference
 "RFC 791: Internet Protocol";
 }
 list address {
 key "ip";
 description
 "The list of IPv4 addresses on the interface.";
 leaf ip {
 type inet:ipv4-address-no-zone;
 description
 "The IPv4 address on the interface.";
 }
 choice subnet {
 description
 "The subnet can be specified as a prefix-length, or,
 if the server supports non-contiguous netmasks, as
 a netmask.";
 leaf prefix-length {
 type uint8 {
 range "0..32";
 }
 description
 "The length of the subnet prefix.";
 }
 leaf netmask {
 if-feature ipv4-non-contiguous-netmasks;
 type yang:dotted-quad;
 description
 "The subnet specified as a netmask.";
 }
 }
 leaf origin {
 type ip-address-origin;
 description
 "The origin of this address.";
 }
 }
 list neighbor {
 key "ip";
 description
 "A list of mappings from IPv4 addresses to
 link-layer addresses.
 This list represents the ARP Cache.";
 reference
 "RFC 826: An Ethernet Address Resolution Protocol";
 leaf ip {
 type inet:ipv4-address-no-zone;
 description
 "The IPv4 address of the neighbor node.";
 }
 leaf link-layer-address {
 type yang:phys-address;
 description
 "The link-layer address of the neighbor node.";
 }
 leaf origin {
 type neighbor-origin;
 description
 "The origin of this neighbor entry.";
 }
 }
 }
 container ipv6 {
 presence "Present if IPv6 is enabled on this interface";
 config false;
 description
 "Parameters for the IPv6 address family.";
 leaf forwarding {
 type boolean;
 default false;
 description
 "Indicates whether IPv6 packet forwarding is enabled or
 disabled on this interface.";
 reference
 "RFC 4861: Neighbor Discovery for IP version 6 (IPv6)
 Section 6.2.1, IsRouter";
 }
 leaf mtu {
 type uint32 {
 range "1280..max";
 }
 units octets;
 description
 "The size, in octets, of the largest IPv6 packet that the
 interface will send and receive.";
 reference
 "RFC 2460: Internet Protocol, Version 6 (IPv6) Specification
 Section 5";
 }
 list address {
 key "ip";
 description
 "The list of IPv6 addresses on the interface.";
 leaf ip {
 type inet:ipv6-address-no-zone;
 description
 "The IPv6 address on the interface.";
 }
 leaf prefix-length {
 type uint8 {
 range "0..128";
 }
 mandatory true;
 description
 "The length of the subnet prefix.";
 }
 leaf origin {
 type ip-address-origin;
 description
 "The origin of this address.";
 }
 leaf status {
 type enumeration {
 enum preferred {
 description
 "This is a valid address that can appear as the
 destination or source address of a packet.";
 }
 enum deprecated {
 description
 "This is a valid but deprecated address that should
 no longer be used as a source address in new
 communications, but packets addressed to such an
 address are processed as expected.";
 }
 enum invalid {
 description
 "This isn't a valid address, and it shouldn't appear
 as the destination or source address of a packet.";
 }
 enum inaccessible {
 description
 "The address is not accessible because the interface
 to which this address is assigned is not
 operational.";
 }
 enum unknown {
 description
 "The status cannot be determined for some reason.";
 }
 enum tentative {
 description
 "The uniqueness of the address on the link is being
 verified. Addresses in this state should not be
 used for general communication and should only be
 used to determine the uniqueness of the address.";
 }
 enum duplicate {
 description
 "The address has been determined to be non-unique on
 the link and so must not be used.";
 }
 enum optimistic {
 description
 "The address is available for use, subject to
 restrictions, while its uniqueness on a link is
 being verified.";
 }
 }
 description
 "The status of an address. Most of the states correspond
 to states from the IPv6 Stateless Address
 Autoconfiguration protocol.";
 reference
 "RFC 4293: Management Information Base for the
 Internet Protocol (IP)
 - IpAddressStatusTC
 RFC 4862: IPv6 Stateless Address Autoconfiguration";
 }
 }
 list neighbor {
 key "ip";
 description
 "A list of mappings from IPv6 addresses to
 link-layer addresses.
 This list represents the Neighbor Cache.";
 reference
 "RFC 4861: Neighbor Discovery for IP version 6 (IPv6)";
 leaf ip {
 type inet:ipv6-address-no-zone;
 description
 "The IPv6 address of the neighbor node.";
 }
 leaf link-layer-address {
 type yang:phys-address;
 description
 "The link-layer address of the neighbor node.";
 }
 leaf origin {
 type neighbor-origin;
 description
 "The origin of this neighbor entry.";
 }
 leaf is-router {
 type empty;
 description
 "Indicates that the neighbor node acts as a router.";
 }
 leaf state {
 type enumeration {
 enum incomplete {
 description
 "Address resolution is in progress, and the link-layer
 address of the neighbor has not yet been
 determined.";
 }
 enum reachable {
 description
 "Roughly speaking, the neighbor is known to have been
 reachable recently (within tens of seconds ago).";
 }
 enum stale {
 description
 "The neighbor is no longer known to be reachable, but
 until traffic is sent to the neighbor no attempt
 should be made to verify its reachability.";
 }
 enum delay {
 description
 "The neighbor is no longer known to be reachable, and
 traffic has recently been sent to the neighbor.
 Rather than probe the neighbor immediately, however,
 delay sending probes for a short while in order to
 give upper-layer protocols a chance to provide
 reachability confirmation.";
 }
 enum probe {
 description
 "The neighbor is no longer known to be reachable, and
 unicast Neighbor Solicitation probes are being sent
 to verify reachability.";
 }
 }
 description
 "The Neighbor Unreachability Detection state of this
 entry.";
 reference
 "RFC 4861: Neighbor Discovery for IP version 6 (IPv6)
 Section 7.3.2";
 }
 }
 }
 }
 }
 <CODE ENDS>
5. IANA Considerations
 This document registers a URI in the "IETF XML Registry" [RFC3688].
 Following the format in RFC 3688, the following registration has been
 made.
 URI: urn:ietf:params:xml:ns:yang:ietf-ip
 Registrant Contact: The NETMOD WG of the IETF.
 XML: N/A; the requested URI is an XML namespace.
 This document registers a YANG module in the "YANG Module Names"
 registry [RFC6020].
 Name: ietf-ip
 Namespace: urn:ietf:params:xml:ns:yang:ietf-ip
 Prefix: ip
 Reference: RFC 7277
6. Security Considerations
 The YANG module defined in this memo is designed to be accessed via
 the NETCONF protocol [RFC6241]. The lowest NETCONF layer is the
 secure transport layer and the mandatory-to-implement secure
 transport is SSH [RFC6242]. The NETCONF access control model
 [RFC6536] provides the means to restrict access for particular
 NETCONF users to a pre-configured subset of all available NETCONF
 protocol operations and content.
 There are a number of data nodes defined in the YANG module which are
 writable/creatable/deletable (i.e., config true, which is the
 default). These data nodes may be considered sensitive or vulnerable
 in some network environments. Write operations (e.g., edit-config)
 to these data nodes without proper protection can have a negative
 effect on network operations. These are the subtrees and data nodes
 and their sensitivity/vulnerability:
 ipv4/enabled and ipv6/enabled: These leafs are used to enable or
 disable IPv4 and IPv6 on a specific interface. By enabling a
 protocol on an interface, an attacker might be able to create an
 unsecured path into a node (or through it if routing is also
 enabled). By disabling a protocol on an interface, an attacker
 might be able to force packets to be routed through some other
 interface or deny access to some or all of the network via that
 protocol.
 ipv4/address and ipv6/address: These lists specify the configured IP
 addresses on an interface. By modifying this information, an
 attacker can cause a node to either ignore messages destined to it
 or accept (at least at the IP layer) messages it would otherwise
 ignore. The use of filtering or security associations may reduce
 the potential damage in the latter case.
 ipv4/forwarding and ipv6/forwarding: These leafs allow a client to
 enable or disable the forwarding functions on the entity. By
 disabling the forwarding functions, an attacker would possibly be
 able to deny service to users. By enabling the forwarding
 functions, an attacker could open a conduit into an area. This
 might result in the area providing transit for packets it
 shouldn't, or it might allow the attacker access to the area,
 bypassing security safeguards.
 ipv6/autoconf: The leafs in this branch control the
 autoconfiguration of IPv6 addresses and, in particular, whether or
 not temporary addresses are used. By modifying the corresponding
 leafs, an attacker might impact the addresses used by a node and
 thus indirectly the privacy of the users using the node.
 ipv4/mtu and ipv6/mtu: Setting these leafs to very small values can
 be used to slow down interfaces.
7. Acknowledgments
 The author wishes to thank Jeffrey Lange, Ladislav Lhotka, Juergen
 Schoenwaelder, and Dave Thaler for their helpful comments.
8. References
8.1. Normative References
 [RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791,
 September 1981.
 [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6
 (IPv6) Specification", RFC 2460, December 1998.
 [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
 January 2004.
 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
 September 2007.
 [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
 Address Autoconfiguration", RFC 4862, September 2007.
 [RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy
 Extensions for Stateless Address Autoconfiguration in
 IPv6", RFC 4941, September 2007.
 [RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the
 Network Configuration Protocol (NETCONF)", RFC 6020,
 October 2010.
 [RFC6241] Enns, R., Bjorklund, M., Schoenwaelder, J., and A.
 Bierman, "Network Configuration Protocol (NETCONF)",
 RFC 6241, June 2011.
 [RFC6991] Schoenwaelder, J., "Common YANG Data Types", RFC 6991,
 July 2013.
 [RFC7223] Bjorklund, M., "A YANG Data Model for Interface
 Management", RFC 7223, May 2014.
 [XML] Bray, T., Paoli, J., Sperberg-McQueen, C., Maler, E., and
 F. Yergeau, "Extensible Markup Language (XML) 1.0 (Fifth
 Edition)", W3C Recommendation, November 2008,
 <http://www.w3.org/TR/xml/>.
8.2. Informative References
 [RFC0826] Plummer, D., "Ethernet Address Resolution Protocol: Or
 converting network protocol addresses to 48.bit Ethernet
 address for transmission on Ethernet hardware", STD 37,
 RFC 826, November 1982.
 [RFC4293] Routhier, S., "Management Information Base for the
 Internet Protocol (IP)", RFC 4293, April 2006.
 [RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure
 Shell (SSH)", RFC 6242, June 2011.
 [RFC6536] Bierman, A. and M. Bjorklund, "Network Configuration
 Protocol (NETCONF) Access Control Model", RFC 6536,
 March 2012.
 [RFC7217] Gont, F., "A Method for Generating Semantically Opaque
 Interface Identifiers with IPv6 Stateless Address
 Autoconfiguration (SLAAC)", RFC 7217, April 2014.
 [ROUTING-MGMT]
 Lhotka, L., "A YANG Data Model for Routing Management",
 Work in Progress, May 2014.
Appendix A. Example: NETCONF <get> Reply
 This section gives an example of a reply to the NETCONF <get> request
 for a device that implements the data model defined in this document.
 The example is written in XML [XML].
 <rpc-reply
 xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"
 message-id="101">
 <data>
 <interfaces
 xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces"
 xmlns:ianaift="urn:ietf:params:xml:ns:yang:iana-if-type">
 <interface>
 <name>eth0</name>
 <type>ianaift:ethernetCsmacd</type>
 <ipv4 xmlns="urn:ietf:params:xml:ns:yang:ietf-ip">
 <address>
 <ip>192.0.2.1</ip>
 <prefix-length>24</prefix-length>
 </address>
 </ipv4>
 <ipv6 xmlns="urn:ietf:params:xml:ns:yang:ietf-ip">
 <mtu>1280</mtu>
 <address>
 <ip>2001:db8::10</ip>
 <prefix-length>32</prefix-length>
 </address>
 <dup-addr-detect-transmits>0</dup-addr-detect-transmits>
 </ipv6>
 </interface>
 </interfaces>
 <interfaces-state
 xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces"
 xmlns:ianaift="urn:ietf:params:xml:ns:yang:iana-if-type">
 <interface>
 <name>eth0</name>
 <type>ianaift:ethernetCsmacd</type>
 <!-- other parameters from ietf-interfaces omitted -->
 <ipv4 xmlns="urn:ietf:params:xml:ns:yang:ietf-ip">
 <forwarding>false</forwarding>
 <mtu>1500</mtu>
 <address>
 <ip>192.0.2.1</ip>
 <prefix-length>24</prefix-length>
 <origin>static</origin>
 </address>
 <neighbor>
 <ip>192.0.2.2</ip>
 <link-layer-address>00:01:02:03:04:05</link-layer-address>
 </neighbor>
 </ipv4>
 <ipv6 xmlns="urn:ietf:params:xml:ns:yang:ietf-ip">
 <forwarding>false</forwarding>
 <mtu>1500</mtu>
 <address>
 <ip>2001:db8::10</ip>
 <prefix-length>32</prefix-length>
 <origin>static</origin>
 <status>preferred</status>
 </address>
 <address>
 <ip>2001:db8::1:100</ip>
 <prefix-length>32</prefix-length>
 <origin>dhcp</origin>
 <status>preferred</status>
 </address>
 <neighbor>
 <ip>2001:db8::1</ip>
 <link-layer-address>00:01:02:03:04:05</link-layer-address>
 <origin>dynamic</origin>
 <is-router/>
 <state>reachable</state>
 </neighbor>
 <neighbor>
 <ip>2001:db8::4</ip>
 <origin>dynamic</origin>
 <state>incomplete</state>
 </neighbor>
 </ipv6>
 </interface>
 </interfaces-state>
 </data>
 </rpc-reply>
Author's Address
 Martin Bjorklund
 Tail-f Systems
 EMail: mbj@tail-f.com