module openconfig-system {

  yang-version "1";

  // namespace
  namespace "http://openconfig.net/yang/system";

  prefix "oc-sys";

  // import some basic types
  import openconfig-inet-types { prefix oc-inet; }
  import ietf-yang-types { prefix yang; }
  import openconfig-types { prefix oc-types; }
  import openconfig-extensions { prefix oc-ext; }
  import openconfig-aaa { prefix oc-aaa; }
  import openconfig-system-logging { prefix oc-log; }
  import openconfig-system-terminal { prefix oc-sys-term; }
  import openconfig-procmon { prefix oc-proc; }


  // meta
  organization "OpenConfig working group";

  contact
    "OpenConfig working group
    netopenconfig@googlegroups.com";

  description
    "Model for managing system-wide services and functions on
    network devices.

    Portions of this code were derived from IETF RFC 7317.
    Please reproduce this note if possible.

    IETF code is subject to the following copyright and license:
    Copyright (c) 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).";

  oc-ext:openconfig-version "0.2.0";

  revision "2017-07-06" {
    description
      "Move to oc-inet types, add IETF attribution, add RADIUS
      counters, changed password leaf names to indicate hashed";
    reference "0.2.0";
  }

  revision "2017-01-29" {
    description
      "Initial public release";
    reference "0.1.0";
  }

  // extension statements

  // feature statements

  // identity statements

  identity NTP_AUTH_TYPE {
    description
      "Base identity for encryption schemes supported for NTP
      authentication keys";
  }

  identity NTP_AUTH_MD5 {
    base NTP_AUTH_TYPE;
    description
      "MD5 encryption method";
  }

  // typedef statements

  typedef timezone-name-type {
    type string;
    description
      "A time zone name as used by the Time Zone Database,
       sometimes referred to as the 'Olson Database'.

       The exact set of valid values is an implementation-specific
       matter.  Client discovery of the exact set of time zone names
       for a particular server is out of scope.";
    reference
      "BCP 175: Procedures for Maintaining the Time Zone Database";
   }

  // grouping statements

  grouping system-clock-config {
    description
      "Configuration data for system-wide clock configuration";

    leaf timezone-name {
      type timezone-name-type;
      description
        "The TZ database name to use for the system, such
         as 'Europe/Stockholm'.";
      reference "IANA Time Zone Database
        http://www.iana.org/time-zones";
    }
  }

  grouping system-clock-state {
    description
      "Operational state data for system-wide clock configuration";
  }

  grouping system-clock-top {
    description
      "Top-level grouping for system-wide clock configuration";

    container clock {
      description
        "Top-level container for clock configuration data";

      container config {
        description
          "Configuration data for system clock";

        uses system-clock-config;
      }

      container state {

        config false;

        description
          "Operational state data for system clock";

        uses system-clock-config;
        uses system-clock-state;
      }
    }
  }

  grouping system-global-config {
    description "system-wide configuration parameters";

    leaf hostname {
      type oc-inet:domain-name;
      description
        "The hostname of the device -- should be a single domain
        label, without the domain.";
    }

    leaf domain-name {
      type oc-inet:domain-name;
      description
        "Specifies the domain name used to form fully qualified name
        for unqualified hostnames.";
    }

    leaf login-banner {
      type string;
      description
        "The console login message displayed before the login prompt,
        i.e., before a user logs into the system.";
    }

    leaf motd-banner {
      type string;
      description
        "The console message displayed after a user logs into the
        system.  They system may append additional standard
        information such as the current system date and time, uptime,
        last login timestamp, etc.";
    }
  }

  grouping system-global-state {
    description
      "Global operational state data for the system";

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

    leaf boot-time {
        type oc-types:timeticks64;
        description
          "This timestamp indicates the time that the system was last
          restarted.  The value is the timestamp in seconds relative
          to the Unix Epoch (Jan 1, 1970 00:00:00 UTC).";
    }

  }

  grouping system-dns-config {
    description "DNS / resolver related configuration data";

    leaf-list search {
      type oc-inet:domain-name;
      ordered-by user;
      description
        "An ordered list of domains to search when resolving
        a host name.";
    }
  }

  grouping system-dns-state {
    description
      "Operational state data for system DNS resolver";

  }

  grouping system-dns-servers-config {
    description
      "Configuration data for DNS resolvers";

    //RFC 7317 includes a single-value choice statement to for
    //TCP and UDP transport.  This has been removed since it the
    //transport protocol is not generally available as an options
    //on target devices.  It may be added back if and when needed.

    leaf address {
      type oc-inet:ip-address;
      description
        "The address of the DNS server, can be either IPv4
        or IPv6.";
    }

    leaf port {
      type oc-inet:port-number;
      default 53;
      description
        "The port number of the DNS server.";
    }

    //RFC 7317 includes resolver timeout and attempts options. These
    //have been omitted as they are not available on many targets. If
    //and when they are required, they may be added back in.
  }

  grouping system-dns-static-config {
    description
      "Configuration data for static host entries";

    leaf hostname {
      type string;
      description
        "Hostname for the static DNS entry";
    }

    leaf-list alias {
      type string;
      description
        "Additional aliases for the hostname";
    }

    leaf-list ipv4-address {
      type oc-inet:ipv4-address;
      description
        "List of IPv4 addressses for the host entry";
    }

    leaf-list ipv6-address {
      type oc-inet:ipv6-address;
      description
        "List of IPv6 addresses for the host entry";
    }
  }

  grouping system-dns-static-state {
    description
      "Operational state data for static host entries";
  }

  grouping system-dns-static-top {
    description
      "Top-level grouping for static DNS host entries";

    container host-entries {
      description
        "Enclosing container for list of static host entries";

      list host-entry {
        key "hostname";
        description
          "List of static host entries";

        leaf hostname {
          type leafref {
            path "../config/hostname";
          }
          description
            "Reference to the hostname list key";
        }

        container config {
          description
            "Configuration data for static host entries";

          uses system-dns-static-config;
        }

        container state {

          config false;

          description
            "Operational state data for static host entries";

          uses system-dns-static-config;
          uses system-dns-static-state;
        }
      }
    }
  }

  grouping system-dns-servers-state {
    description
      "Operational state data for DNS resolvers";

  }

  grouping system-dns-servers-top {
    description
      "Top-level grouping for the list of DNS resolvers.";

    container servers {
      description
        "Enclosing container for DNS resolver list";

      list server {
        key "address";
        ordered-by user;
        description
          "List of the DNS servers that the resolver should query.

           When the resolver is invoked by a calling application, it
           sends the query to the first name server in this list.  If
           no response has been received within 'timeout' seconds,
           the resolver continues with the next server in the list.
           If no response is received from any server, the resolver
           continues with the first server again.  When the resolver
           has traversed the list 'attempts' times without receiving
           any response, it gives up and returns an error to the
           calling application.

           Implementations MAY limit the number of entries in this
           list.";

        leaf address {
          type leafref {
            path "../config/address";
          }
          description
            "References the configured address of the DNS server";
        }

        container config {
          description
            "Configuration data for each DNS resolver";

          uses system-dns-servers-config;
        }

        container state {

          config false;

          description
            "Operational state data for each DNS resolver";

          uses system-dns-servers-config;
          uses system-dns-servers-state;
        }

      }
    }
  }

  grouping system-dns-top {
    description
      "Top-level grouping for DNS / resolver config and operational
      state data";

    container dns {
      description
        "Enclosing container for DNS resolver data";

      container config {
        description
          "Configuration data for the DNS resolver";

        uses system-dns-config;

      }

      container state {

        config false;

        description
          "Operational state data for the DNS resolver";

        uses system-dns-config;
        uses system-dns-state;

      }

      uses system-dns-servers-top;
      uses system-dns-static-top;
    }
  }

  grouping system-ntp-server-config {
    description
      "Configuration data for NTP servers";

    leaf address {
      type oc-inet:host;
      description
        "The address or hostname of the NTP server.";
    }

    leaf port {
      type oc-inet:port-number;
      default 123;
      description
        "The port number of the NTP server.";
    }

    leaf version {
      type uint8 {
        range 1..4;
      }
      default 4;
      description
        "Version number to put in outgoing NTP packets";
    }

    leaf association-type {
      type enumeration {
        enum SERVER {
          description
            "Use client association mode.  This device
             will not provide synchronization to the
             configured NTP server.";
        }
        enum PEER {
          description
            "Use symmetric active association mode.
             This device may provide synchronization
             to the configured NTP server.";
        }
        enum POOL {
          description
            "Use client association mode with one or
             more of the NTP servers found by DNS
             resolution of the domain name given by
             the 'address' leaf.  This device will not
             provide synchronization to the servers.";
        }
      }
      default SERVER;
      description
        "The desired association type for this NTP server.";
    }
    leaf iburst {
      type boolean;
      default false;
      description
        "Indicates whether this server should enable burst
        synchronization or not.";
    }
    leaf prefer {
      type boolean;
      default false;
      description
        "Indicates whether this server should be preferred
        or not.";
    }
  }

  grouping system-ntp-server-state {
    description
      "Operational state data for NTP servers";

    leaf stratum {
      type uint8;
      description
        "Indicates the level of the server in the NTP hierarchy. As
        stratum number increases, the accuracy is degraded.  Primary
        servers are stratum while a maximum value of 16 indicates
        unsynchronized.  The values have the following specific
        semantics:

        | 0      | unspecified or invalid
        | 1      | primary server (e.g., equipped with a GPS receiver)
        | 2-15   | secondary server (via NTP)
        | 16     | unsynchronized
        | 17-255 | reserved";
      reference
        "RFC 5905 - Network Time Protocol Version 4: Protocol and
        Algorithms Specification";
    }

    leaf root-delay {
      type uint32;
      // TODO: reconsider units for these values -- the spec defines
      // rootdelay and rootdisperson as 2 16-bit integers for seconds
      // and fractional seconds, respectively.  This gives a
      // precision of ~15 us (2^-16).  Using milliseconds here based
      // on what implementations typically provide and likely lack
      // of utility for less than millisecond precision with NTP
      // time sync.
      units "milliseconds";
      description
        "The round-trip delay to the server, in milliseconds.";
      reference
        "RFC 5905 - Network Time Protocol Version 4: Protocol and
        Algorithms Specification";
    }

    leaf root-dispersion {
      type uint64;
      units "milliseconds";
      description
        "Dispersion (epsilon) represents the maximum error inherent
        in the measurement";
      reference
        "RFC 5905 - Network Time Protocol Version 4: Protocol and
        Algorithms Specification";
    }

    leaf offset {
      type uint64;
      units "milliseconds";
      description
        "Estimate of the current time offset from the peer.  This is
        the time difference between the local and reference clock.";
    }

    leaf poll-interval {
      type uint32;
      units "seconds";
      description
        "Polling interval of the peer";
    }
  }

  grouping system-ntp-server-top {
    description
      "Top-level grouping for the list of NTP servers";

    container servers {
      description
        "Enclosing container for the list of NTP servers";

      list server {
        key "address";
        description
          "List of NTP servers to use for system clock
          synchronization.  If '/system/ntp/enabled'
          is 'true', then the system will attempt to
          contact and utilize the specified NTP servers.";

        leaf address {
          type leafref {
            path "../config/address";
          }
          description
            "References the configured address or hostname of the
            NTP server.";
        }

        container config {
          description
            "Configuration data for an NTP server.";

          uses system-ntp-server-config;
        }

        container state {

          config false;

          description
            "Operational state data for an NTP server.";

          uses system-ntp-server-config;
          uses system-ntp-server-state;
        }

      }
    }
  }

  grouping system-ntp-auth-keys-config {
    description
      "Configuration data ";

    leaf key-id {
      type uint16;
      description
        "Integer identifier used by the client and server to
        designate a secret key.  The client and server must use
        the same key id.";
    }

    leaf key-type {
      type identityref {
        base NTP_AUTH_TYPE;
      }
      description
        "Encryption type used for the NTP authentication key";
    }

    leaf key-value {
      type string;
      description
        "NTP authentication key value";
    }
  }

  grouping system-ntp-auth-keys-state {
    description
      "Operational state data for NTP auth key data";
  }

  grouping system-ntp-auth-keys-top {
    description
      "Top-level grouping for NTP auth key data";

    container ntp-keys {
      description
        "Enclosing container for list of NTP authentication keys";

      list ntp-key {
        key "key-id";
        description
          "List of NTP authentication keys";

        leaf key-id {
          type leafref {
            path "../config/key-id";
          }
          description
            "Reference to auth key-id list key";
        }

        container config {
          description
            "Configuration data for NTP auth keys";

          uses system-ntp-auth-keys-config;
        }

        container state {

          config false;

          description
            "Operational state data for NTP auth keys";

          uses system-ntp-auth-keys-config;
          uses system-ntp-auth-keys-state;
        }
      }
    }
  }

  grouping system-ntp-config {
    description
      "Configuration data for system-wide NTP operation.";

    leaf enabled {
      type boolean;
      default false;
      description
        "Enables the NTP protocol and indicates that the system should
        attempt to synchronize the system clock with an NTP server
        from the servers defined in the 'ntp/server' list.";
    }

    leaf ntp-source-address {
      type oc-inet:ip-address;
      description
        "Source address to use on outgoing NTP packets";
    }

    leaf enable-ntp-auth {
      type boolean;
      default false;
      description
        "Enable or disable NTP authentication -- when enabled, the
        system will only use packets containing a trusted
        authentication key to synchronize the time.";
    }
  }

  grouping system-ntp-state {
    description
      "Operational state data for system-wide NTP operation.";

    leaf auth-mismatch {
      type yang:counter64;
      description
        "Count of the number of NTP packets received that were not
        processed due to authentication mismatch.";
    }
  }

  grouping system-ntp-top {
    description
      "Top-level grouping for configuration and state data for NTP";

    container ntp {
      description
        "Top-level container for NTP configuration and state";

      container config {
        description
          "Configuration data for NTP client.";

        uses system-ntp-config;
      }

      container state {

        config false;

        description
          "Operational state data for NTP services.";

        uses system-ntp-config;
        uses system-ntp-state;
      }
      uses system-ntp-auth-keys-top;
      uses system-ntp-server-top;
    }
  }

  grouping system-memory-config {
    description
      "Configuration data for system memory";
  }

  grouping system-memory-state {
    description
      "Operational state data for system memory";

    leaf physical {
      type uint64;
      units bytes;
      // TODO: consider making units in megabytes
      description
        "Reports the total physical memory available on the
        system.";
    }

    leaf reserved {
      type uint64;
      units bytes;
      description
        "Memory reserved for system use";
    }
  }

  grouping system-memory-top {
    description
      "Top-level grouping for system memory data definitions";

    container memory {
      description
        "Top-level container for system memory data";

      container config {
        description
          "Configuration data for system memory";

        uses system-memory-config;
      }

      container state {

        config false;

        description
          "Operational state data for system memory";

        uses system-memory-config;
        uses system-memory-state;
      }
    }
  }


  grouping system-top {
    description
      "Top level system data containers";

    container system {
      description
        "Enclosing container for system-related configuration and
        operational state data";

      container config {
        description "Global configuration data for the system";

        uses system-global-config;

      }

      container state {

        config false;

        description "Global operational state data for the system";

        uses system-global-config;
        uses system-global-state;

      }

      uses system-clock-top;
      uses system-dns-top;
      uses system-ntp-top;
      uses oc-sys-term:system-ssh-server-top;
      uses oc-sys-term:system-telnet-server-top;
      uses oc-log:logging-top;
      uses oc-aaa:aaa-top;
      uses system-memory-top;
      uses oc-proc:procmon-processes-top;
    }
  }

  // data definition statements

  uses system-top;

}