Network Working Group A. Bierman
Internet-Draft Netconf Central
Intended status: Standards Track M. Bjorklund
Expires: August 02, 2012 Tail-f Systems
February 01, 2012

YANG Data Model for System Management
draft-ietf-netmod-system-mgmt-00

Abstract

This document defines a YANG data model for the configuration and identification of the management system of a device.

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 August 02, 2012.

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.


Table of Contents

1. Introduction

This document defines a YANG [RFC6020] data model for the configuration and identification of the management system of a device.

Devices that are managed by NETCONF and perhaps other mechanisms have common properties that need to be configured and monitored in a standard way.

The YANG module defined in this document provides the following features:

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].

1.1.1. Terms

The following terms are used within this document:

2. Objectives

2.1. System Identification

There are many common properties used to identify devices, operating systems, software versions, etc. that need to be supported in the system data module. These objects are defined as operational data and intended to be specific to the device vendor.

Some user-configurable administrative strings are also provided such as the system location and description.

2.2. System Time Management

The management of the date and time used by the system need to be supported. Use of one or more NTP servers to automatically set the system date and time need to be possible. Utilization of the Timezone database [I-D.lear-iana-timezone-database] also need to be supported.

2.3. User Authentication

The authentication mechanism need to support password authentication over RADIUS, to support deployment scenarios with centralized authentication servers. Additionally, local users need to be supported, for scenarios when no centralized authentication server exists, or for situations where the centralized authentication server cannot be reached from the device.

Since the mandatory transport protocol for NETCONF is SSH [RFC6242] the authentication model need to support SSH's "publickey" and "password" authentication methods [RFC4252].

The model for authentication configuration should be flexible enough to support authentication methods defined by other standard documents or by vendors.

3. System Data Model

3.1. System Identification

The data model for system identification has the following structure:

   +--rw system
      +--rw contact?          string
      +--rw name?             string
      +--rw location?         string
      +--ro platform
         +--ro os-name?       string
         +--ro os-release?    string
         +--ro os-version?    string
         +--ro machine?       string
         +--ro nodename?      string
	    

3.2. System Time Management

The data model for system time management has the following structure:

   +--rw system
      +--rw clock
      |  +--ro current-datetime?      yang:date-and-time
      |  +--ro boot-datetime?         yang:date-and-time
      |  +--rw (timezone)?
      |     +--:(timezone-location)
      |     |  +--rw timezone-location?     string
      |     +--:(timezone-name)
      |     |  +--rw timezone-name?         string
      |     +--:(timezone-utc-offset)
      |        +--rw timezone-utc-offset?   int16
      +--rw ntp
         +--rw use-ntp?      boolean
         +--rw ntp-server [address]
            +--rw address    inet:host
            +--rw enabled    boolean
	    

3.3. DNS Resolver Model

The data model for configuration of the DNS resolver has the following structure:

   +--rw system
      +--rw dns
         +--rw search*    inet:host
         +--rw server*    inet:ip-address
         +--rw options
            +--rw ndots?      uint8
            +--rw timeout?    uint8
            +--rw attempts?   uint8
	    

3.4. RADIUS Client Model

The data model for configuration of the RADIUS client has the following structure:

   +--rw system
      +--rw radius
         +--rw server [address]
         |  +--rw address                inet:host
         |  +--rw authentication-port?   inet:port-number
         |  +--rw shared-secret?         string
         +--rw options
            +--rw timeout?    uint8
            +--rw attempts?   uint8
	    

3.5. User Authentication Model

This document defines three authentication methods for use with NETCONF:

Additional methods can be defined by other standard documents or by vendors.

This document defines two optional YANG features, "local‑users" and "radius‑authentication", which the server advertises to indicate support for configuring local users on the device, and support for using RADIUS for authentication, respectively.

The authentication parameters defined in this document are primarily used to configure authentication of NETCONF users, but MAY also be used by other interfaces, e.g., a Command Line Interface or a Web-based User Interface.

The data model for user authentication has the following structure:

   +--rw system
      +--rw authentication
         +--rw user-authentication-order*   identityref
         +--rw user [name]
            +--rw name        string
            +--rw password?   crypt-hash
            +--rw ssh-dsa?    binary
            +--rw ssh-rsa?    binary
	    

3.5.1. SSH Public Key Authentication

If the NETCONF server advertises the "local‑users" feature, configuration of local users and their SSH public keys is supported in the /system/authentication/user list.

Public key authentication is requested by the SSH client. If the "local‑users" feature is supported, then when a NETCONF client starts an SSH session towards the server using the "publickey" authentication "method name" [RFC4252], the SSH server looks up the user name given in the SSH authentication request in the /system/authentication/user list, and verifies the key as described in [RFC4253].

3.5.2. Local User Password Authentication

If the NETCONF server advertises the "local‑users" feature, configuration of local users and their passwords is supported in the /system/authentication/user list.

For NETCONF transport protocols that support password authentication, the leaf-list "user‑authentication‑order" is used to control if local user password authentication should be used.

In SSH, password authentication is requested by the client. Other NETCONF transport protocols MAY also support password authentication.

When local user password authentication is requested, the NETCONF transport looks up the user name provided by the client in the /system/ authentication/user list, and verifies the password.

3.5.3. RADIUS Password Authentication

If the NETCONF server advertises the "radius‑authentication" feature, the device supports user authentication using RADIUS.

For NETCONF transport protocols that support password authentication, the leaf-list "user‑authentication‑order" is used to control if RADIUS password authentication should be used.

In SSH, password authentication is requested by the client. Other NETCONF transport protocols MAY also support password authentication.

3.6. System Control

Two protocol operations are included to restart or shutdown the system. The 'system‑restart' operation can be used to restart the entire system (not just the NETCONF server). The 'system‑shutdown' operation can be used to power off the entire system.

4. System YANG module

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

This YANG module imports YANG extensions from [I-D.ietf-netconf-access-control], imports YANG types from [RFC6021], and references [RFC1321], [RFC2865], [RFC3418], [RFC5607], [IEEE-1003.1-2008], and [FIPS.180-3.2008].

<CODE BEGINS> file "ietf-system@2012-01-31.yang"

module ietf-system {
  namespace "urn:ietf:params:xml:ns:yang:ietf-system";
  prefix "sys";

  import ietf-yang-types {
    prefix yang;
  }

  import ietf-inet-types {
    prefix inet;
  }

  import ietf-netconf-acm {
    prefix nacm;
  }

  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:   Andy Bierman
               <mailto:andy@netconfcentral.org>

     Editor:   Martin Bjorklund
               <mailto:mbj@tail-f.com>";
  
  description
    "This module contains a collection of YANG definitions for the
     configuration and identification of the management system of a
     device.

     Copyright (c) 2011 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 XXXX; see
     the RFC itself for full legal notices.";

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

  // RFC Ed.: remove this note
  // Note: extracted from draft-ietf-netmod-system-mgmt-00.txt

  // RFC Ed.: update the date below with the date of RFC publication
  // and remove this note.
  revision 2012-01-31 {
    description
      "Initial revision.";
    reference
      "RFC XXXX: A YANG Data Model for System Management";
  }
  
  /*
   * Typedefs
   */ 

  typedef timezone-name {
    description
      "List of available timezone enumerations.
       Based on the referenced list, but non-unique names
       have been changed so they are unique enumeration
       identifiers.";
    reference
      "Wikipedia: http://en.wikipedia.org/wiki/"
       + "List_of_time_zone_abbreviations";
    type enumeration {
      enum ACDT {
        description
          "Australian Central Daylight Time UTC+10:30";
      }
      enum ACST {
        description
          "Australian Central Standard Time UTC+09:30";
      }
      enum ACT {
        description
          "ASEAN Common Time UTC+08";
      }
      enum ADT {
        description
          "Atlantic Daylight Time UTC−03";
      }
      enum AEDT {
        description
          "Australian Eastern Daylight Time UTC+11";
      }
      enum AEST {
        description
          "Australian Eastern Standard Time UTC+10";
      }
      enum AFT {
        description
          "Afghanistan Time UTC+04:30";
      }
      enum AKDT {
        description
          "Alaska Daylight Time UTC−08";
      }
      enum AKST {
        description
          "Alaska Standard Time UTC−09";
      }
      enum AMST {
        description
          "Armenia Summer Time UTC+05";
      }
      enum AMT {
        description
          "Armenia Time UTC+04";
      }
      enum ART {
        description
          "Argentina Time UTC−03";
      }
      enum AST {
        description
          "Arab Standard Time (Kuwait, Riyadh) UTC+03";
      }
      enum AST-2 {
        description
          "Arabian Standard Time (Abu Dhabi, Muscat) UTC+04";
      }
      enum AST-3 {
        description
          "Arabic Standard Time (Baghdad) UTC+03";
      }
      enum AST-4 {
        description
          "Atlantic Standard Time UTC−04";
      }
      enum AWDT {
        description
          "Australian Western Daylight Time UTC+09";
      }
      enum AWST {
        description
          "Australian Western Standard Time UTC+08";
      }
      enum AZOST {
        description
          "Azores Standard Time UTC−01";
      }
      enum AZT {
        description
          "Azerbaijan Time UTC+04";
      }
      enum BDT {
        description
          "Brunei Time UTC+08";
      }
      enum BIOT {
        description
          "British Indian Ocean Time UTC+06";
      }
      enum BIT {
        description
          "Baker Island Time UTC−12";
      }
      enum BOT {
        description
          "Bolivia Time UTC−04";
      }
      enum BRT {
        description
          "Brasilia Time UTC−03";
      }
      enum BST {
        description
          "Bangladesh Standard Time UTC+06";
      }
      enum BST-2 {
        description
          "British Summer Time (British Standard Time 
           from Feb 1968 to Oct 1971) UTC+01";
      }
      enum BTT {
        description
          "Bhutan Time UTC+06";
      }
      enum CAT {
        description
          "Central Africa Time UTC+02";
      }
      enum CCT {
        description
          "Cocos Islands Time UTC+06:30";
      }
      enum CDT {
        description
          "Central Daylight Time (North America) UTC−05";
      }
      enum CEDT {
        description
          "Central European Daylight Time UTC+02";
      }
      enum CEST {
        description
          "Central European Summer Time (Cf. HAEC) UTC+02";
      }
      enum CET {
        description
          "Central European Time UTC+01";
      }
      enum CHADT {
        description
          "Chatham Daylight Time UTC+13:45";
      }
      enum CHAST {
        description
          "Chatham Standard Time UTC+12:45";
      }
      enum CIST {
        description
          "Clipperton Island Standard Time UTC−08";
      }
      enum CKT {
        description
          "Cook Island Time UTC−10";
      }
      enum CLST {
        description
          "Chile Summer Time UTC−03";
      }
      enum CLT {
        description
          "Chile Standard Time UTC−04";
      }
      enum COST {
        description
          "Colombia Summer Time UTC−04";
      }
      enum COT {
        description
          "Colombia Time UTC−05";
      }
      enum CST {
        description
          "Central Standard Time (North America) UTC−06";
      }
      enum CST-2 {
        description
          "China Standard Time UTC+08";
      }
      enum CST-3 {
        description
          "Central Standard Time (Australia) UTC+09:30";
      }
      enum CT {
        description
          "China Time UTC+08";
      }
      enum CVT {
        description
          "Cape Verde Time UTC−01";
      }
      enum CXT {
        description
          "Christmas Island Time UTC+07";
      }
      enum CHST {
        description
          "Chamorro Standard Time UTC+10";
      }
      enum DFT {
        description
          "AIX specific equivalent of Central European Time UTC+01";
      }
      enum EAST {
        description
          "Easter Island Standard Time UTC−06";
      }
      enum EAT {
        description
          "East Africa Time UTC+03";
      }
      enum ECT {
        description
          "Eastern Caribbean Time (does not recognise DST) UTC−04";
      }
      enum ECT-2 {
        description
          "Ecuador Time UTC−05";
      }
      enum EDT {
        description
          "Eastern Daylight Time (North America) UTC−04";
      }
      enum EEDT {
        description
          "Eastern European Daylight Time UTC+03";
      }
      enum EEST {
        description
          "Eastern European Summer Time UTC+03";
      }
      enum EET {
        description
          "Eastern European Time UTC+02";
      }
      enum EST {
        description
          "Eastern Standard Time (North America) UTC−05";
      }
      enum FJT {
        description
          "Fiji Time UTC+12";
      }
      enum FKST {
        description
          "Falkland Islands Summer Time UTC−03";
      }
      enum FKT {
        description
          "Falkland Islands Time UTC−04";
      }
      enum GALT {
        description
          "Galapagos Time UTC−06";
      }
      enum GET {
        description
          "Georgia Standard Time UTC+04";
      }
      enum GFT {
        description
          "French Guiana Time UTC−03";
      }
      enum GILT {
        description
          "Gilbert Island Time UTC+12";
      }
      enum GIT {
        description
          "Gambier Island Time UTC−09";
      }
      enum GMT {
        description
          "Greenwich Mean Time UTC";
      }
      enum GST {
        description
          "South Georgia and the South Sandwich Islands UTC−02";
      }
      enum GST-2 {
        description
          "Gulf Standard Time UTC+04";
      }
      enum GYT {
        description
          "Guyana Time UTC−04";
      }
      enum HADT {
        description
          "Hawaii-Aleutian Daylight Time UTC−09";
      }
      enum HAEC {
        description
          "Heure Avancée d'Europe Centrale francised name for 
           CEST UTC+02";
      }
      enum HAST {
        description
          "Hawaii-Aleutian Standard Time UTC−10";
      }
      enum HKT {
        description
          "Hong Kong Time UTC+08";
      }
      enum HMT {
        description
          "Heard and McDonald Islands Time UTC+05";
      }
      enum HST {
        description
          "Hawaii Standard Time UTC−10";
      }
      enum ICT {
        description
          "Indochina Time UTC+07";
      }
      enum IDT {
        description
          "Israeli Daylight Time UTC+03";
      }
      enum IRKT {
        description
          "Irkutsk Time UTC+08";
      }
      enum IRST {
        description
          "Iran Standard Time UTC+03:30";
      }
      enum IST {
        description
          "Indian Standard Time UTC+05:30";
      }
      enum IST-2 {
        description
          "Irish Summer Time UTC+01";
      }
      enum IST-3 {
        description
          "Israel Standard Time UTC+02";
      }
      enum JST {
        description
          "Japan Standard Time UTC+09";
      }
      enum KRAT {
        description
          "Krasnoyarsk Time UTC+07";
      }
      enum KST {
        description
          "Korea Standard Time UTC+09";
      }
      enum LHST {
        description
          "Lord Howe Standard Time UTC+10:30";
      }
      enum LINT {
        description
          "Line Islands Time UTC+14";
      }
      enum MAGT {
        description
          "Magadan Time UTC+11";
      }
      enum MDT {
        description
          "Mountain Daylight Time (North America) UTC−06";
      }
      enum MET {
        description
          "Middle European Time Same zone as CET UTC+02";
      }
      enum MEST {
        description
          "Middle European Saving Time Same zone as CEST UTC+02";
      }
      enum MIT {
        description
          "Marquesas Islands Time UTC−09:30";
      }
      enum MSD {
        description
          "Moscow Summer Time UTC+04";
      }
      enum MSK {
        description
          "Moscow Standard Time UTC+03";
      }
      enum MST {
        description
          "Malaysian Standard Time UTC+08";
      }
      enum MST-2 {
        description
          "Mountain Standard Time (North America) UTC−07";
      }
      enum MST-3 {
        description
          "Myanmar Standard Time UTC+06:30";
      }
      enum MUT {
        description
          "Mauritius Time UTC+04";
      }
      enum MYT {
        description
          "Malaysia Time UTC+08";
      }
      enum NDT {
        description
          "Newfoundland Daylight Time UTC−02:30";
      }
      enum NFT {
        description
          "Norfolk Time[1] UTC+11:30";
      }
      enum NPT {
        description
          "Nepal Time UTC+05:45";
      }
      enum NST {
        description
          "Newfoundland Standard Time UTC−03:30";
      }
      enum NT {
        description
          "Newfoundland Time UTC−03:30";
      }
      enum NZDT {
        description
          "New Zealand Daylight Time UTC+13";
      }
      enum NZST {
        description
          "New Zealand Standard Time UTC+12";
      }
      enum OMST {
        description
          "Omsk Time UTC+06";
      }
      enum PDT {
        description
          "Pacific Daylight Time (North America) UTC−07";
      }
      enum PETT {
        description
          "Kamchatka Time UTC+12";
      }
      enum PHOT {
        description
          "Phoenix Island Time UTC+13";
      }
      enum PKT {
        description
          "Pakistan Standard Time UTC+05";
      }
      enum PST {
        description
          "Pacific Standard Time (North America) UTC−08";
      }
      enum PST-2 {
        description
          "Philippine Standard Time UTC+08";
      }
      enum RET {
        description
          "Réunion Time UTC+04";
      }
      enum SAMT {
        description
          "Samara Time UTC+04";
      }
      enum SAST {
        description
          "South African Standard Time UTC+02";
      }
      enum SBT {
        description
          "Solomon Islands Time UTC+11";
      }
      enum SCT {
        description
          "Seychelles Time UTC+04";
      }
      enum SGT {
        description
          "Singapore Time UTC+08";
      }
      enum SLT {
        description
          "Sri Lanka Time UTC+05:30";
      }
      enum SST {
        description
          "Samoa Standard Time UTC−11";
      }
      enum SST-2 {
        description
          "Singapore Standard Time UTC+08";
      }
      enum TAHT {
        description
          "Tahiti Time UTC−10";
      }
      enum THA {
        description
          "Thailand Standard Time UTC+07";
      }
      enum UTC {
        description
          "Coordinated Universal Time UTC";
      }
      enum UYST {
        description
          "Uruguay Summer Time UTC−02";
      }
      enum UYT {
        description
          "Uruguay Standard Time UTC−03";
      }
      enum VET {
        description
          "Venezuelan Standard Time UTC−04:30";
      }
      enum VLAT {
        description
          "Vladivostok Time UTC+10";
      }
      enum WAT {
        description
          "West Africa Time UTC+01";
      }
      enum WEDT {
        description
          "Western European Daylight Time UTC+01";
      }
      enum WEST {
        description
          "Western European Summer Time UTC+01";
      }
      enum WET {
        description
          "Western European Time UTC";
      }
      enum WST {
        description
          "Western Standard Time UTC+08";
      }
      enum YAKT {
        description
          "Yakutsk Time UTC+09";
      }
      enum YEKT {
        description
          "Yekaterinburg Time UTC+05";
      }
    }
  }

  typedef crypt-hash {
    type string {
      pattern "$0$.* | $1|5|6$[a-zA-Z0-9./]{2,16}$.*";
    }
    description
      "The crypt-hash type is used to store passwords using
       a hash function.  This type is implemented in various UNIX
       systems as the function crypt(3).

       When a clear text value is set to a leaf of this type, the
       server calculates a password hash, and stores the result
       in the datastore.  Thus, the password is never stored in
       clear text.

       When a leaf of this type is read, the stored password hash is
       returned.

       A value of this type matches one of the forms:

         $0$<clear text password>
         $<id>$<salt>$<password hash>

      The '$0$' prefix signals that the value is clear text.  When
      such a value is received by the server, a hash value is
      calculated, and the string '$<id>$<salt>$' is prepended to the
      result, where <salt> is a random 2-16 characters long salt
      used to generate the digest.  This value is stored in the
      configuration data store.

      If a value starting with '$<id>$<salt>$' is received, the
      server knows that the value already represents a hashed value,
      and stores it as is in the data store.

      When a server needs to verify a password given by a user, it
      finds the stored password hash string for that user, extracts
      the salt, and calculates the hash with the salt and given
      password as input.  If the calculated hash value is the same
      as the stored value, the password given by the client is
      correct.

      This type defines the following hash functions:

        id | hash function | feature
        ---+---------------+-------------------
         1 | MD5           | crypt-hash-md5
         5 | SHA-256       | crypt-hash-sha-256
         6 | SHA-512       | crypt-hash-sha-512

      The server indicates support for the different hash functions
      by advertising the corresponding feature.";
    reference
      "IEEE Std 1003.1-2008 - crypt() function
       Wikipedia: http://en.wikipedia.org/wiki/Crypt_(Unix)
       RFC 1321: The MD5 Message-Digest Algorithm
       FIPS.180-3.2008: Secure Hash Standard";
  }

  /*
   * Features
   */
  
  feature radius {
    description
      "Indicates that the device can be configured as a RADIUS
       client.";
    reference
      "RFC 2865: Remote Authentication Dial In User Service "
    + "(RADIUS)";
  }

  feature authentication {
    description
      "Indicates that the device can be configured
       to do authentication of users.";
  }

  feature local-users {
    if-feature authentication;
    description
      "Indicates that the device supports
       local user authentication.";
  }
  
  feature radius-authentication {
    if-feature radius;
    if-feature authentication;
    description
      "Indicates that the device supports user authentication over
       RADIUS.";
    reference
      "RFC 2865: Remote Authentication Dial In User Service (RADIUS)
       RFC 5607: Remote Authentication Dial-In User Service (RADIUS)
                 Authorization for Network Access Server (NAS)
                 Management";
  }

  feature crypt-hash-md5 {
    description
      "Indicates that the device supports the MD5
       hash function in 'crypt-hash' values";
    reference "RFC 1321: The MD5 Message-Digest Algorithm";
  }

  feature crypt-hash-sha-256 {
    description
      "Indicates that the device supports the SHA-256
       hash function in 'crypt-hash' values";
    reference "FIPS.180-3.2008: Secure Hash Standard";
  }

  feature crypt-hash-sha-512 {
    description
      "Indicates that the device supports the SHA-512
       hash function in 'crypt-hash' values";
    reference "FIPS.180-3.2008: Secure Hash Standard";
  }

  feature ntp {
    description
      "Indicates that the device can be configured
       to use one or more NTP servers to set the 
       system date and time.";
  }

  feature timezone-location {
    description
      "Indicates that the local timezone on the device
       can be configured to use the TZ database
       to set the timezone and manage daylight savings time.";
    reference
      "TZ Database  http://www.twinsun.com/tz/tz-link.htm
       Maintaining the Timezone Database
         draft-lear-iana-timezone-database-04.txt";
  }

  feature timezone-name {
    description
      "Indicates that the local timezone on the device
       can be configured using the timezone enumeration
       strings as an alias for an UTC offset.";
    reference
      "Wikipedia: http://en.wikipedia.org/wiki/"
    + "List_of_time_zone_abbreviations";
  }

  /*
   * Identities
   */
  
  identity authentication-method {
    description
      "Base identity for user authentication methods.";
  }
  
  identity radius {
    base authentication-method;
    description
      "Indicates user authentication using RADIUS.";
    reference
      "RFC 2865: Remote Authentication Dial In User Service (RADIUS)
       RFC 5607: Remote Authentication Dial-In User Service (RADIUS)
                 Authorization for Network Access Server (NAS)
                 Management";
  }

  identity local-users {
    base authentication-method;
    description
      "Indicates password-based authentication of locally
       configured users.";
  }

  /*
   * Top-level container
   */

  container system {
    description
      "System group configuration.";
    
    leaf contact { 
      type string {
        length "0..255";
      }
      default "";
      description
        "The administrator contact information for the system.";
      reference
        "RFC 3418 - Management Information Base (MIB) for the
                    Simple Network Management Protocol (SNMP)
                    SNMPv2-MIB.sysContact";
    }
    
    leaf name {
      type string {
        length "0..255";
      }
      default "";
      description
        "The administratively assigned system name.";
      reference
        "RFC 3418 - Management Information Base (MIB) for the
                    Simple Network Management Protocol (SNMP)
                    SNMPv2-MIB.sysName";
    }
    
    leaf location {
      type string {
        length "0..255";
      }
      default "";
      description
        "The system location";
      reference
        "RFC 3418 - Management Information Base (MIB) for the
                    Simple Network Management Protocol (SNMP)
                    SNMPv2-MIB.sysLocation";
    }

    container platform {
      config false;
      description
        "Contains vendor-specific information for
         identifying the system platform and operating system.";
      reference
        "IEEE Std 1003.1-2008 - sys/utsname.h";

      leaf os-name {
        type string;
        description
          "The name of the operating system in use,
           for example 'Linux'";
        reference
          "IEEE Std 1003.1-2008 - utsname.sysname";
      }

      leaf os-release {
        type string;
        description
          "The current release level of the operating
           system in use.  This string MAY indicate
           the OS source code revision.";
        reference
          "IEEE Std 1003.1-2008 - utsname.release";
      }

      leaf os-version {
        type string;
        description
          "The current version level of the operating
           system in use.  This string MAY indicate
           the specific OS build date and target variant
           information.";
        reference
          "IEEE Std 1003.1-2008 - utsname.version";
      }

      leaf machine {
        type string;
        description 
          "A vendor-specific identifier string representing
           the hardware in use.";
        reference
          "IEEE Std 1003.1-2008 - utsname.machine";
      }

      leaf nodename {
        type string;
        description
          "The host name of this system.";
        reference
          "IEEE Std 1003.1-2008 - utsname.nodename";
      }
    }

    container clock {
      description
        "Configuration and monitoring of the system
         date and time properties.";

      leaf current-datetime {
        type yang:date-and-time;
        config false;
        description 
          "The current system date and time.";
      }

      leaf boot-datetime {
        type yang:date-and-time;
        config false;
        description
          "The system date and time when the NETCONF
           server last restarted.";
      }

      choice timezone {
        description
          "Configure the system timezone information.";

        leaf timezone-location {
          if-feature timezone-location;
          type string;
          description
            "The TZ database location identifier string
             to use for the system, such as 'Europe/Stockholm'.";
        }

        leaf timezone-name {
          if-feature timezone-name;
          type timezone-name; 
          description
            "The timezone enumeration string to use
             for the system, such as 'CET'.";
        }

        leaf timezone-utc-offset {
          type int16 {
            range "-1439 .. 1439";
          }
          description
            "The number of minutes to add to UTC time to
             identify the timezone for this system.
             For example, 'UTC - 8:00 hours' would be
             represented as '-480'.";
        }
      }
    }

    container ntp {
      if-feature ntp;

      description
        "Configuration of the NTP client.";

      leaf use-ntp {
        type boolean;
        default true;
        description
          "Indicates that the system should attempt
           to synchronize the system clock with an
           NTP server from the 'ntp-server' list.";
      }

      list ntp-server {
        key address;
        ordered-by user;
        description
          "List of NTP servers to use for
           system clock synchronization.  If 'use-ntp'
           is 'true', then the system will attempt to
           contact and utilize the specified NTP servers.
           The user specified order indicates the server priority.";

        leaf address {
          type inet:host;
          description
            "The IP address or domain name of the NTP server.";
        }
        leaf enabled {
          type boolean;
          default true;
          description
            "Indicates whether this server is enabled for use or
             not.";
        }
      }
    }

    container dns {
      description
        "Configuration of the DNS resolver.";

      leaf-list search {
        type inet:host;
        ordered-by user;
        description
          "An ordered list of domains to search when resolving 
           a host name.";
      }
      leaf-list server {
        type inet:ip-address;
        ordered-by user;
        description
          "Addresses of the name servers that the resolver should
           query.

           Implementations MAY limit the number of entries in this
           leaf list.";
      }
      container options {
        description
          "Resolver options.  The set of available options has been
           limited to those that are generally available across
           different resolver implementations, and generally
           useful.";
        leaf ndots {
          type uint8;
          default "1";
          description
            "This parameter sets a threshold for the number of dots 
             which must appear in a query request before an initial
             absolute query will be made.";
        }
        leaf timeout {
          type uint8;
          units "seconds";
          default "5";
          description
            "The amount of time the resolver will wait for a 
             response from a remote name server before 
             retrying the query via a different name server.";
        }
        leaf attempts {
          type uint8;
          default "2";
          description
            "The number of times the resolver will send a query to 
             its name servers before giving up and returning an 
             error to the calling application.";
        }
      }
    }

    container radius {
      if-feature radius;

      description
        "Configuration of the RADIUS client.";

      list server {
        key address;
        ordered-by user;
        description
          "List of RADIUS servers used by the device.";

        leaf address {
          type inet:host;
          description
            "The address of the RADIUS server.";
        }
        leaf authentication-port {
          type inet:port-number;
          default "1812";
          description
            "The port number of the RADIUS server.";
        }
        leaf shared-secret {
          type string;
          nacm:default-deny-all;
          description
            "The shared secret which is known to both the RADIUS
             client and server.";
          reference
            "RFC 2865: Remote Authentication Dial In User Service";
        }
      }
      container options {
        description
          "RADIUS client options.";
        
        leaf timeout {
          type uint8;
          units "seconds";
          default "5";
          description
            "The number of seconds the device will wait for a
             response from a RADIUS server before trying with a
             different server.";
        }
        leaf attempts {
          type uint8;
          default "2";
          description
            "The number of times the device will send a query to
             the RADIUS servers before giving up.";
        }
      }
    }

    container authentication {
      nacm:default-deny-write;
      if-feature authentication;

       description
         "The authentication configuration subtree.";

       leaf-list user-authentication-order {
         type identityref {
           base authentication-method;
         }
         must '(. = "sys:radius" and ../../radius/server) or'
            + '(. != "sys:radius")' {
           error-message
             "When 'radius' is used, a radius server"
           + " must be configured.";
         }
         ordered-by user;

         description
           "When the device authenticates a user with
            a password, it tries the authentication methods in this
            leaf-list in order.  If authentication with one method
            fails, the next method is used.  If no method succeeds,
            the user is denied access.

            If the 'radius-authentication' feature is advertised by
            the NETCONF server, the 'radius' identity can be added to
            this list.

            If the 'local-users' feature is advertised by the
            NETCONF server, the 'local-users' identity can be
            added to this list.";
       }

       list user {
         if-feature local-users;
         key name;
         description
           "The list of local users configured on this device.";
         
         leaf name {
           type string;
           description
            "The user name string identifying this entry.";
         }
         leaf password {
           type crypt-hash;
           description
             "The password for this entry.";
         }
         leaf ssh-dsa {
           type binary;
           description
             "The public DSA key for this entry.";
         }
         leaf ssh-rsa {
           type binary;
           description
             "The public RSA key for this entry.";
         }
       }
     }
  }

  rpc set-current-datetime {
    nacm:default-deny-all;
    description
      "Manually set the /system/clock/current-datetime leaf
       to the specified value.

       If the /system/ntp/ntp-in-use leaf exists and
       is set to 'true', then this operation will
       fail with error-tag 'operation-failed',
       and error-app-tag value of 'ntp-active'";
    input {
      leaf current-datetime {
        type yang:date-and-time;
        mandatory true;
        description 
          "The current system date and time.";
      }
    }
  }

  rpc system-restart {
    nacm:default-deny-all;
    description
      "Request that the entire system be restarted immediately.
       A server SHOULD send an rpc reply to the client before
       restarting the system.";
  }

  rpc system-shutdown {
    nacm:default-deny-all;
    description
      "Request that the entire system be shut down immediately.
       A server SHOULD send an rpc reply to the client before
       shutting down the system.";
  }


}

	    

<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 is requested to be made.

     URI: urn:ietf:params:xml:ns:yang:ietf-system

     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-system
  namespace:    urn:ietf:params:xml:ns:yang:ietf-system
  prefix:       sys
  reference:    RFC XXXX
	    

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 this 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:

Some of the readable data nodes in this YANG module may be considered sensitive or vulnerable in some network environments. It is thus important to control read access (e.g., via get, get-config, or notification) to these data nodes. These are the subtrees and data nodes and their sensitivity/vulnerability:

Some of the RPC operations in this YANG module may be considered sensitive or vulnerable in some network environments. It is thus important to control access to these operations. These are the operations and their sensitivity/vulnerability:

7. References

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, January 2004.
[RFC4252] Ylonen, T. and C. Lonvick, "The Secure Shell (SSH) Authentication Protocol", RFC 4252, January 2006.
[RFC4253] Ylonen, T. and C. Lonvick, "The Secure Shell (SSH) Transport Layer Protocol", RFC 4253, January 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.
[I-D.lear-iana-timezone-database] Lear, E and P Eggert, "IANA Procedures for Maintaining the Timezone Database", Internet-Draft draft-lear-iana-timezone-database-04, May 2011.
[I-D.ietf-netconf-access-control] Bierman, A and M Bjorklund, "Network Configuration Protocol (NETCONF) Access Control Model", Internet-Draft draft-ietf-netconf-access-control-05, October 2011.
[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.
[RFC1321] Rivest, R., "The MD5 Message-Digest Algorithm", RFC 1321, April 1992.
[RFC2865] Rigney, C., Willens, S., Rubens, A. and W. Simpson, "Remote Authentication Dial In User Service (RADIUS)", RFC 2865, June 2000.
[RFC3418] Presuhn, R., "Management Information Base (MIB) for the Simple Network Management Protocol (SNMP)", STD 62, RFC 3418, December 2002.
[RFC5607] Nelson, D. and G. Weber, "Remote Authentication Dial-In User Service (RADIUS) Authorization for Network Access Server (NAS) Management", RFC 5607, July 2009.
[FIPS.180-3.2008] National Institute of Standards and Technology, "Secure Hash Standard", FIPS PUB 180-3, October 2008.
[IEEE-1003.1-2008] Institute of Electrical and Electronics Engineers, "POSIX.1-2008", IEEE Standard 1003.1, March 2008.

Authors' Addresses

Andy Bierman Netconf Central EMail: andy@netconfcentral.org
Martin Bjorklund Tail-f Systems EMail: mbj@tail-f.com