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Versions: (draft-bjorklund-netmod-ip-cfg) 00 01 02 03 04 05 06 07 09 10 11 12 13 14 RFC 7277

Network Working Group                                       M. Bjorklund
Internet-Draft                                            Tail-f Systems
Intended status: Standards Track                       November 15, 2012
Expires: May 19, 2013


                  A YANG Data Model for IP Management
                      draft-ietf-netmod-ip-cfg-07

Abstract

   This document defines a YANG data model for management of IP
   implementations.

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
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on May 19, 2013.

Copyright Notice

   Copyright (c) 2012 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.






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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1.  Terminology  . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  IP Data Model  . . . . . . . . . . . . . . . . . . . . . . . .  4
   3.  Relationship to IP-MIB . . . . . . . . . . . . . . . . . . . .  6
   4.  IP configuration YANG Module . . . . . . . . . . . . . . . . .  7
   5.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 15
   6.  Security Considerations  . . . . . . . . . . . . . . . . . . . 16
   7.  Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . . 18
   8.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 19
     8.1.  Normative References . . . . . . . . . . . . . . . . . . . 19
     8.2.  Informative References . . . . . . . . . . . . . . . . . . 19
   Appendix A.  Example: NETCONF <get> reply  . . . . . . . . . . . . 21
   Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 22




































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1.  Introduction

   This document defines a YANG [RFC6020] data model for management of
   IP implementations.

   The initial version of this data model focuses on configuration
   parameters for interfaces.  Future revisions of this data model might
   add other kinds of IP parameters.

   Parameters to manage IP routing are defined in
   [I-D.ietf-netmod-routing-cfg].

1.1.  Terminology

   The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14, [RFC2119].

   The following terms are defined in [RFC6241] and are not redefined
   here:

   o  client

   o  server

   The following terms are defined in [RFC6020] and are not redefined
   here:

   o  augment

   o  data model

   o  data node

















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2.  IP Data Model

   The module "ietf-ip" augments the "interface" list defined in the
   "ietf-interfaces" module [I-D.ietf-netmod-interfaces-cfg] with the
   following data nodes, where square brackets are used to enclose a
   list's keys, and "?" means that the node is optional.  Choice and
   case nodes are enclosed in parenthesis, and a case node is marked
   with a colon (":").

      +--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
            |  |  +--rw (subnet)?
            |  |     +--:(prefix-length)
            |  |     |  +--rw ip:prefix-length?   uint8
            |  |     +--:(netmask)
            |  |        +--rw ip:netmask?         inet:ipv4-address
            |  +--rw neighbor [ip]
            |     +--rw ip               inet:ipv4-address
            |     +--rw phys-address?    yang:phys-address
            +--rw ipv6?
               +--rw enabled?            boolean
               +--rw forwarding?         boolean
               +--rw mtu?                uint32
               +--rw address [ip]
               |  +--rw ip               inet:ipv6-address
               |  +--rw prefix-length?   uint8
               +--rw neighbor [ip]
               |  +--rw ip               inet:ipv6-address
               |  +--rw phys-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 containers, "ipv4" and "ipv6",
   representing the IPv4 and IPv6 address families.  In each container,
   there is a leaf "enabled" that controls if the address family is
   enabled on that interface, and a leaf "forwarding" that controls if
   ip packet forwarding for the address family is enabled on the



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   interface.  In each container, there is also a list of addresses, and
   a list of mappings from ip addresses to physical addresses.

















































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3.  Relationship to IP-MIB

   If the device implements 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.  The
   corresponding YANG data nodes are defined in
   [I-D.ietf-netmod-routing-cfg].

   The entries in "ipv4/neighbor" and "ipv6/neighbor" are mapped to
   ipNetToPhysicalTable.

   The object ipAddressStatus is writable in the IP-MIB but does not
   represent configuration, and is thus not mapped to the YANG module.

   The following table lists the YANG data nodes with corresponding
   objects in the IP-MIB.

          +-----------------+-----------------------------------+
          | YANG data node  | IP-MIB object                     |
          +-----------------+-----------------------------------+
          | ipv4/enabled    | ipv4InterfaceEnableStatus         |
          | ipv4/address    | ipAddressEntry                    |
          | ipv4/address/ip | ipAddressAddrType / ipAddressAddr |
          | ipv4/neighbor   | ipNetToPhysicalTable              |
          | ipv6/enabled    | ipv6InterfaceEnableStatus         |
          | ipv6/forwarding | ipv6InterfaceForwarding           |
          | ipv6/address    | ipAddressEntry                    |
          | ipv6/address/ip | ipAddressAddrType / ipAddressAddr |
          | ipv6/neighbor   | ipNetToPhysicalTable              |
          +-----------------+-----------------------------------+

               Mapping of YANG data nodes to IP-MIB objects

















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4.  IP configuration YANG Module

   This module imports typedefs from [RFC6021] and
   [I-D.ietf-netmod-interfaces-cfg], and references [RFC0791],
   [RFC0826], [RFC2460], [RFC4861], [RFC4862], and [RFC4941].

   RFC Ed.: update the date below with the date of RFC publication and
   remove this note.

   <CODE BEGINS> file "ietf-ip@2012-11-15.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: David Kessens
                  <mailto:david.kessens@nsn.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) 2012 IETF Trust and the persons identified as
        authors of the code.  All rights reserved.



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        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 XXXX; see
        the RFC itself for full legal notices.";

     // RFC Ed.: replace XXXX with actual RFC number and remove this
     // note.

     // RFC Ed.: update the date below with the date of RFC publication
     // and remove this note.
     revision 2012-11-15 {
       description
         "Initial revision.";
       reference
         "RFC XXXX: A YANG Data Model for IP Configuration";
     }

     /* 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";
     }

     /* 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.";




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       container ipv4 {
         presence "Configure IPv4 on this interface.";
         description
           "Parameters for the IPv4 address family.";

         leaf enabled {
           type boolean;
           default true;
           description
             "Controls if IPv4 is enabled or disabled on this
              interface.";
         }
         leaf forwarding {
           type boolean;
           default false;
           description
             "Controls if 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.

              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 IPv4 addresses on the interface.";

           leaf ip {
             type inet:ipv4-address;
             description
               "The IPv4 address on the interface.";
           }
           choice subnet {
             default prefix-length;



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             description
               "The subnet can be specified as a prefix-length, or,
                if the server supports non-contiguous netmasks, as
                a netmask.

                The default subnet is a prefix-length of 32.";
             leaf prefix-length {
               type uint8 {
                 range "0..32";
               }
               default 32;
               description
                 "The length of the subnet prefix.";
             }
             leaf netmask {
               if-feature ipv4-non-contiguous-netmasks;
               type inet:ipv4-address;
               description
                 "The subnet specified as a netmask.";
             }
           }
         }
         list neighbor {
           key "ip";
           description
             "A list of mappings from IPv4
              addresses to physical 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;
             description
               "The IPv4 address of a neighbor node.";
           }
           leaf phys-address {
             type yang:phys-address;
             description
               "The physical level address of the neihgbor node.";
           }
         }

       }
       container ipv6 {
         presence "Configure IPv6 on this interface.";



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         description
           "Parameters for the IPv6 address family.";

         leaf enabled {
           type boolean;
           default true;
           description
             "Controls if IPv6 is enabled or disabled on this
              interface.";
         }
         leaf forwarding {
           type boolean;
           default false;
           description
             "Controls if 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.

              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: IPv6 Specification
                        Section 5";
         }
         list address {
           key "ip";
           description
             "The list of IPv6 addresses on the interface.";

           leaf ip {
             type inet:ipv6-address;
             description
               "The IPv6 address on the interface.";
           }



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           leaf prefix-length {
             type uint8 {
               range "0..128";
             }
             default 128;
             description
               "The length of the subnet prefix.";
           }
         }
         list neighbor {
           key "ip";
           description
             "A list of mappings from IPv6
              addresses to physical 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;
             description
               "The IPv6 address of a neighbor node.";
           }
           leaf phys-address {
             type yang:phys-address;
             description
               "The physical level 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.";



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           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 section 5.5 of RFC 4862.";
             reference
               "RFC 4862: IPv6 Stateless Address Autoconfiguration";
           }
           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_PREFERED_LIFETIME";



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           }
         }
       }
     }
   }

   <CODE ENDS>












































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5.  IANA Considerations

   This document registers a URI in the IETF XML registry [RFC3688].
   Following the format in RFC 3688, the following registration is
   requested to be 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 XXXX
































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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].

   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 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
      temporary addresses are used or not.  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.





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   ipv4/mtu and ipv6/mtu:  Setting these leafs to very small values can
      be used to slow down interfaces.

















































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7.  Acknowledgments

   The author wishes to thank Ladislav Lhotka, Juergen Schoenwaelder,
   and Dave Thaler for their helpful comments.















































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8.  References

8.1.  Normative References

   [I-D.ietf-netmod-interfaces-cfg]
              Bjorklund, M., "A YANG Data Model for Interface
              Configuration", draft-ietf-netmod-interfaces-cfg-05 (work
              in progress), July 2012.

   [RFC0791]  Postel, J., "Internet Protocol", STD 5, RFC 791,
              September 1981.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [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.

   [RFC6021]  Schoenwaelder, J., "Common YANG Data Types", RFC 6021,
              October 2010.

8.2.  Informative References

   [I-D.ietf-netmod-routing-cfg]
              Lhotka, L., "A YANG Data Model for Routing Configuration",
              draft-ietf-netmod-routing-cfg-04 (work in progress),
              July 2012.

   [RFC0826]  Plummer, D., "Ethernet Address Resolution Protocol: Or
              converting network protocol addresses to 48.bit Ethernet



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              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.

   [RFC6241]  Enns, R., Bjorklund, M., Schoenwaelder, J., and A.
              Bierman, "Network Configuration Protocol (NETCONF)",
              RFC 6241, June 2011.

   [RFC6242]  Wasserman, M., "Using the NETCONF Protocol over Secure
              Shell (SSH)", RFC 6242, June 2011.







































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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.

   <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">
         <interface>
           <name>eth0</name>
           <type>ethernetCsmacd</type>
           <location>0</location>
           <if-index>2</if-index>
           <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::1</ip>
               <prefix-length>32</prefix-length>
             </address>
             <dup-addr-detect-transmits>0</dup-addr-detect-transmits>
           </ipv6>
         </interface>
       </interfaces>
     </data>
   </rpc-reply>

















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Author's Address

   Martin Bjorklund
   Tail-f Systems

   Email: mbj@tail-f.com













































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