module ietf-dhcpv6-server {

    yang-version 1.1;

    namespace
      "urn:ietf:params:xml:ns:yang:ietf-dhcpv6-server";

    prefix dhc6-srv;

    import ietf-inet-types {
      prefix inet;
      reference
        "RFC 6991: Common YANG Data Types";


    }
    import ietf-yang-types {
      prefix yang;
      reference
        "RFC 6991: Common YANG Data Types";


    }
    import ietf-dhcpv6-common {
      prefix dhc6;
      reference
        "RFC 9243: A YANG Data Model for DHCPv6 Configuration";


    }
    import ietf-netconf-acm {
      prefix nacm;
      reference
        "RFC 8341: Network Configuration Access Control Model";


    }

    organization
      "IETF Dynamic Host Configuration (DHC) Working Group";

    contact
      "WG Web:   <https://datatracker.ietf.org/wg/dhc/>
WG List:  <mailto:dhcwg@ietf.org>
Author:   Yong Cui <yong@csnet1.cs.tsinghua.edu.cn>
Author:   Linhui Sun <lh.sunlinh@gmail.com>
Editor:   Ian Farrer <ian.farrer@telekom.de>
Author:   Sladjana Zeichlin <sladjana.zechlin@telekom.de>
Author:   Zihao He <hezihao9512@gmail.com>
Author:   Michal Nowikowski <godfryd@isc.org>";

    description
      "This YANG module defines components for the configuration
and management of DHCPv6 servers.

Copyright (c) 2022 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 Revised BSD License set
forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents
(https://trustee.ietf.org/license-info).

This version of this YANG module is part of RFC 9243
(https://www.rfc-editor.org/info/rfc9243); see the RFC itself
for full legal notices.";

    revision "2022-06-20" {
      description "Initial revision.";
      reference
        "RFC 9243: A YANG Data Model for DHCPv6 Configuration";

    }


    feature na-assignment {
      description
        "Denotes that the server implements DHCPv6 non-temporary
address assignment.";
      reference
        "RFC 8415: Dynamic Host Configuration Protocol for
        IPv6 (DHCPv6), Section 6.2";

    }

    feature prefix-delegation {
      description
        "Denotes that the server implements DHCPv6 prefix
delegation.";
      reference
        "RFC 8415: Dynamic Host Configuration Protocol for
        IPv6 (DHCPv6), Section 6.3";

    }

    grouping resource-config {
      description
        "Nodes that are reused at multiple levels in the DHCPv6
server's addressing hierarchy.";
      leaf-list option-set-id {
        type leafref {
          path
            "/dhcpv6-server/option-sets/option-set/option-set-id";
        }
        description
          "The ID field of the relevant set of DHCPv6 options
(option-set) to be provisioned to clients using the
allocation-range.";
      }

      leaf valid-lifetime {
        type dhc6:timer-seconds32;
        description
          "Valid lifetime for the Identity Association (IA).";
        reference
          "RFC 8415: Dynamic Host Configuration Protocol for
          IPv6 (DHCPv6), Section 12.1";

      }

      leaf renew-time {
        type dhc6:timer-seconds32;
        description "Renew (T1) time.";
        reference
          "RFC 8415: Dynamic Host Configuration Protocol for
          IPv6 (DHCPv6), Section 4.2";

      }

      leaf rebind-time {
        type dhc6:timer-seconds32;
        description "Rebind (T2) time.";
        reference
          "RFC 8415: Dynamic Host Configuration Protocol for
          IPv6 (DHCPv6), Section 4.2";

      }

      leaf preferred-lifetime {
        type dhc6:timer-seconds32;
        description
          "Preferred lifetime for the IA.";
        reference
          "RFC 8415: Dynamic Host Configuration Protocol for
          IPv6 (DHCPv6), Section 12.1";

      }

      leaf rapid-commit {
        type boolean;
        description
          "When set to 'true', specifies that client-server exchanges
involving two messages is supported.";
        reference
          "RFC 8415: Dynamic Host Configuration Protocol for
          IPv6 (DHCPv6), Section 5.1";

      }
    }  // grouping resource-config

    grouping lease-information {
      description
        "Binding information for each client that has been allocated
an IPv6 address or prefix.";
      leaf client-duid {
        type dhc6:duid;
        description "Client DUID.";
        reference
          "RFC 8415: Dynamic Host Configuration Protocol for
          IPv6 (DHCPv6), Section 11";

      }

      leaf ia-id {
        type uint32;
        mandatory true;
        description
          "Client's Identity Association IDentifier (IAID).";
        reference
          "RFC 8415: Dynamic Host Configuration Protocol for
          IPv6 (DHCPv6), Section 12";

      }

      leaf allocation-time {
        type yang:date-and-time;
        description
          "Time and date that the lease was made.";
        reference
          "RFC 8415: Dynamic Host Configuration Protocol for
          IPv6 (DHCPv6), Section 18";

      }

      leaf last-renew-rebind {
        type yang:date-and-time;
        description
          "Time of the last successful renew or rebind.";
        reference
          "RFC 8415: Dynamic Host Configuration Protocol for
          IPv6 (DHCPv6), Section 18";

      }

      leaf preferred-lifetime {
        type dhc6:timer-seconds32;
        description
          "The preferred lifetime expressed in seconds.";
        reference
          "RFC 8415: Dynamic Host Configuration Protocol for
          IPv6 (DHCPv6), Section 6";

      }

      leaf valid-lifetime {
        type dhc6:timer-seconds32;
        description
          "The valid lifetime for the lease expressed in seconds.";
        reference
          "RFC 8415: Dynamic Host Configuration Protocol for
          IPv6 (DHCPv6), Section 6";

      }

      leaf lease-t1 {
        type dhc6:timer-seconds32;
        description
          "The time interval after which the client should contact
the server from which the addresses in the IA_NA were
obtained to extend the lifetimes of the addresses assigned
to the Identity Association for Prefix Delegation (IA_PD).";
        reference
          "RFC 8415: Dynamic Host Configuration Protocol for
          IPv6 (DHCPv6), Section 4.2";

      }

      leaf lease-t2 {
        type dhc6:timer-seconds32;
        description
          "The time interval after which the client should contact
any available server to extend the lifetimes of the
addresses assigned to the IA_PD.";
        reference
          "RFC 8415: Dynamic Host Configuration Protocol for
          IPv6 (DHCPv6), Section 4.2";

      }

      uses dhc6:status;
    }  // grouping lease-information

    grouping message-statistics {
      description
        "Counters for DHCPv6 messages.";
      leaf discontinuity-time {
        type yang:date-and-time;
        description
          "The time on the most recent occasion at which any one or
more of DHCPv6 server's counters suffered a discontinuity.
If no such discontinuities have occurred since the last
re-initialization of the local management subsystem, then
this node contains the time the local management subsystem
re-initialized itself.";
      }

      leaf solicit-count {
        type yang:counter32;
        config false;
        description
          "Number of Solicit (1) messages received.";
      }

      leaf advertise-count {
        type yang:counter32;
        config false;
        description
          "Number of Advertise (2) messages sent.";
      }

      leaf request-count {
        type yang:counter32;
        config false;
        description
          "Number of Request (3) messages received.";
      }

      leaf confirm-count {
        type yang:counter32;
        config false;
        description
          "Number of Confirm (4) messages received.";
      }

      leaf renew-count {
        type yang:counter32;
        config false;
        description
          "Number of Renew (5) messages received.";
      }

      leaf rebind-count {
        type yang:counter32;
        config false;
        description
          "Number of Rebind (6) messages received.";
      }

      leaf reply-count {
        type yang:counter32;
        config false;
        description
          "Number of Reply (7) messages sent.";
      }

      leaf release-count {
        type yang:counter32;
        config false;
        description
          "Number of Release (8) messages received.";
      }

      leaf decline-count {
        type yang:counter32;
        config false;
        description
          "Number of Decline (9) messages received.";
      }

      leaf reconfigure-count {
        type yang:counter32;
        config false;
        description
          "Number of Reconfigure (10) messages sent.";
      }

      leaf information-request-count {
        type yang:counter32;
        config false;
        description
          "Number of Information-request (11) messages
received.";
      }

      leaf discarded-message-count {
        type yang:counter32;
        config false;
        description
          "Number of messages that have been discarded for any
reason.";
      }
    }  // grouping message-statistics

    grouping preference-option-group {
      description
        "OPTION_PREFERENCE (7) Preference Option.";
      reference
        "RFC 8415: Dynamic Host Configuration Protocol for
        IPv6 (DHCPv6), Section 21.8";

      container preference-option {
        description
          "OPTION_PREFERENCE (7) Preference Option.";
        leaf pref-value {
          type uint8;
          description
            "The preference value for the server in this message.  A
1-octet unsigned integer.";
        }
      }  // container preference-option
    }  // grouping preference-option-group

    grouping server-unicast-option-group {
      description
        "OPTION_UNICAST (12) Server Unicast Option.";
      reference
        "RFC 8415: Dynamic Host Configuration Protocol for
        IPv6 (DHCPv6), Section 21.12";

      container server-unicast-option {
        description
          "OPTION_UNICAST (12) Server Unicast Option.";
        leaf server-address {
          type inet:ipv6-address;
          description
            "The 128-bit address to which the client should send
messages delivered using unicast.";
        }
      }  // container server-unicast-option
    }  // grouping server-unicast-option-group

    grouping reconfigure-message-option-group {
      description
        "OPTION_RECONF_MSG (19) Reconfigure Message Option.";
      reference
        "RFC 8415: Dynamic Host Configuration Protocol for
        IPv6 (DHCPv6), Section 21.19";

      container reconfigure-message-option {
        description
          "OPTION_RECONF_MSG (19) Reconfigure Message Option.";
        leaf msg-type {
          type uint8;
          description
            "5 for Renew message, 6 for Rebind message, and 11 for
Information-request message.";
        }
      }  // container reconfigure-message-option
    }  // grouping reconfigure-message-option-group

    grouping info-refresh-time-option-group {
      description
        "OPTION_INFORMATION_REFRESH_TIME (32) Information Refresh
Time Option.";
      reference
        "RFC 8415: Dynamic Host Configuration Protocol for
        IPv6 (DHCPv6), Section 21.23";

      container info-refresh-time-option {
        description
          "OPTION_INFORMATION_REFRESH_TIME (32) Information Refresh
Time Option.";
        leaf info-refresh-time {
          type dhc6:timer-seconds32;
          description
            "Time duration specifying an upper bound for how long a
client should wait before refreshing information retrieved
from a DHCP server.";
        }
      }  // container info-refresh-time-option
    }  // grouping info-refresh-time-option-group

    grouping sol-max-rt-option-group {
      description
        "OPTION_SOL_MAX_RT (82) SOL_MAX_RT Option (Max Solicit timeout
 value).";
      reference
        "RFC 8415: Dynamic Host Configuration Protocol for
        IPv6 (DHCPv6), Section 21.24";

      container sol-max-rt-option {
        description
          "OPTION_SOL_MAX_RT (82) SOL_MAX_RT Option.";
        leaf sol-max-rt-value {
          type dhc6:timer-seconds32;
          description
            "Maximum Solicit timeout value.";
        }
      }  // container sol-max-rt-option
    }  // grouping sol-max-rt-option-group

    grouping inf-max-rt-option-group {
      description
        "OPTION_INF_MAX_RT (83) INF_MAX_RT Option (Max
 Information-request timeout value).";
      reference
        "RFC 8415: Dynamic Host Configuration Protocol for
        IPv6 (DHCPv6), Section 21.25";

      container inf-max-rt-option {
        description
          "OPTION_INF_MAX_RT (83) INF_MAX_RT Option.";
        leaf inf-max-rt-value {
          type dhc6:timer-seconds32;
          description
            "Maximum Information-request timeout value.";
        }
      }  // container inf-max-rt-option
    }  // grouping inf-max-rt-option-group

    container dhcpv6-server {
      description
        "Configuration nodes for the DHCPv6 server.";
      reference
        "RFC 8415: Dynamic Host Configuration Protocol for
        IPv6 (DHCPv6), Section 18.3";

      leaf enabled {
        type boolean;
        description
          "Enables the DHCP server function.";
      }

      leaf server-duid {
        type dhc6:duid;
        description "DUID of the server.";
        reference
          "RFC 8415: Dynamic Host Configuration Protocol for
          IPv6 (DHCPv6), Section 11";

      }

      container vendor-config {
        description
          "This container provides a location for augmenting vendor
or implementation-specific configuration nodes.";
      }  // container vendor-config

      container option-sets {
        description
          "A server may allow different option sets to be configured
for clients matching specific parameters, such as
topological location or client type.  The 'option-set' list
is a set of options and their contents that will be
returned to clients.";
        reference
          "RFC 8415: Dynamic Host Configuration Protocol for
          IPv6 (DHCPv6), Section 21";

        list option-set {
          key "option-set-id";
          description
            "YANG definitions for DHCPv6 options are contained in
separate YANG modules and augmented to this container as
required.";
          leaf option-set-id {
            type string;
            description
              "Option set identifier.";
          }

          leaf description {
            type string;
            description
              "An optional field for storing additional information
relevant to the option set.";
          }

          uses preference-option-group;

          uses dhc6:auth-option-group;

          uses server-unicast-option-group;

          uses dhc6:rapid-commit-option-group;

          uses dhc6:vendor-specific-information-option-group;

          uses reconfigure-message-option-group;

          uses dhc6:reconfigure-accept-option-group;

          uses info-refresh-time-option-group;

          uses sol-max-rt-option-group;

          uses inf-max-rt-option-group;
        }  // list option-set
      }  // container option-sets

      container class-selector {
        description
          "DHCPv6 servers use a 'class-selector' function in order
to identify and classify incoming client messages
so that they can be given the correct configuration.
The mechanisms used for implementing this function vary
greatly between different implementations; as such, it is
not possible to include them in this module.  This container
provides a location for server implementors to augment their
own class-selector YANG.";
      }  // container class-selector

      container allocation-ranges {
        description
          "This model is based on an address and parameter
allocation hierarchy.  The top level is 'global' -- which
is defined as the container for all allocation-ranges.
Under this are the individual allocation-ranges.";
        uses resource-config;

        list allocation-range {
          key "id";
          description
            "Network ranges are identified by the 'id' key.";
          leaf id {
            type string;
            mandatory true;
            description
              "Unique identifier for the allocation range.";
          }

          leaf description {
            type string;
            description
              "Description for the allocation range.";
          }

          leaf network-prefix {
            type inet:ipv6-prefix;
            mandatory true;
            description "Network prefix.";
          }

          uses resource-config;

          container address-pools {
            if-feature na-assignment;
            description
              "Configuration for the DHCPv6 server's
address pools.";
            list address-pool {
              key "pool-id";
              description
                "List of address pools for allocation to clients,
distinguished by 'pool-id'.";
              leaf pool-id {
                type string;
                mandatory true;
                description
                  "Unique identifier for the pool.";
              }

              leaf pool-prefix {
                type inet:ipv6-prefix;
                mandatory true;
                description
                  "IPv6 prefix for the pool.  Should be contained
within the network-prefix if configured.";
              }

              leaf start-address {
                type inet:ipv6-address-no-zone;
                mandatory true;
                description
                  "Starting IPv6 address for the pool.";
              }

              leaf end-address {
                type inet:ipv6-address-no-zone;
                mandatory true;
                description
                  "Ending IPv6 address for the pool.";
              }

              leaf max-address-utilization {
                type dhc6:threshold;
                description
                  "Maximum amount of the addresses in the
pool that can be simultaneously allocated,
calculated as a percentage of the available
addresses (end-address minus start-address plus
one), and rounded up. Used to set the value for
the address-pool-utilization-threshold-exceeded
notification.";
              }

              uses resource-config;

              container host-reservations {
                description
                  "Configuration for host reservations from the
address pool.";
                list host-reservation {
                  key "reserved-addr";
                  description
                    "List of host reservations.";
                  leaf client-duid {
                    type dhc6:duid;
                    description
                      "Client DUID for the reservation.";
                  }

                  leaf reserved-addr {
                    type inet:ipv6-address;
                    description
                      "Reserved IPv6 address.";
                  }

                  uses resource-config;
                }  // list host-reservation
              }  // container host-reservations

              container active-leases {
                config false;
                description
                  "Holds state related to active client
leases.";
                leaf total-count {
                  type uint64;
                  mandatory true;
                  description
                    "The total number of addresses in the pool.";
                }

                leaf allocated-count {
                  type uint64;
                  mandatory true;
                  description
                    "The number of addresses or prefixes in the pool
that are currently allocated.";
                }

                list active-lease {
                  key "leased-address";
                  description
                    "List of active address leases.";
                  leaf leased-address {
                    type inet:ipv6-address;
                    description
                      "Active address lease entry.";
                  }

                  uses lease-information;
                }  // list active-lease
              }  // container active-leases
            }  // list address-pool
          }  // container address-pools

          container prefix-pools {
            if-feature prefix-delegation;
            description
              "Configuration for the DHCPv6 server's prefix pools.";
            list prefix-pool {
              key "pool-id";
              description
                "List of prefix pools for allocation to clients,
distinguished by 'pool-id'.";
              leaf pool-id {
                type string;
                mandatory true;
                description
                  "Unique identifier for the pool.";
              }

              leaf pool-prefix {
                type inet:ipv6-prefix;
                mandatory true;
                description
                  "IPv6 prefix for the pool.  Should be contained
within the network-prefix if configured.";
              }

              leaf client-prefix-length {
                type uint8 {
                  range "1 .. 128";
                }
                mandatory true;
                description
                  "Length of the prefixes that will be delegated
to clients.";
              }

              leaf max-pd-space-utilization {
                type dhc6:threshold;
                description
                  "Maximum amount of the prefixes in the pool that
can be simultaneously allocated, calculated as a
percentage of the available prefixes, and rounded
up.  Used to set the value for the
prefix-pool-utilization-threshold-exceeded
notification.";
              }

              uses resource-config;

              container host-reservations {
                description
                  "Configuration for host reservations from the
prefix pool.";
                list prefix-reservation {
                  key "reserved-prefix";
                  description
                    "Reserved prefix reservation.";
                  leaf client-duid {
                    type dhc6:duid;
                    description
                      "Client DUID for the reservation.";
                  }

                  leaf reserved-prefix {
                    type inet:ipv6-prefix;
                    description
                      "Reserved IPv6 prefix.";
                  }

                  leaf reserved-prefix-len {
                    type uint8;
                    description
                      "Reserved IPv6 prefix length.";
                  }
                }  // list prefix-reservation

                uses resource-config;
              }  // container host-reservations

              container active-leases {
                config false;
                description
                  "Holds state related to active client prefix
leases.";
                leaf total-count {
                  type uint64;
                  mandatory true;
                  description
                    "The total number of prefixes in the pool.";
                }

                leaf allocated-count {
                  type uint64;
                  mandatory true;
                  description
                    "The number of prefixes in the pool that are
currently allocated.";
                }

                list active-lease {
                  key "leased-prefix";
                  description
                    "List of active prefix leases.";
                  leaf leased-prefix {
                    type inet:ipv6-prefix;
                    description
                      "Active leased prefix entry.";
                  }

                  uses lease-information;
                }  // list active-lease
              }  // container active-leases
            }  // list prefix-pool
          }  // container prefix-pools
        }  // list allocation-range

        container statistics {
          description
            "DHCPv6 message counters for the server.";
          uses message-statistics;
        }  // container statistics
      }  // container allocation-ranges
    }  // container dhcpv6-server

    rpc delete-address-lease {
      nacm:default-deny-all;
      if-feature na-assignment;
      description
        "Deletes a client's active address lease from the server's
lease database.  Note that this will not cause the address
to be revoked from the client, and the lease may be refreshed
or renewed by the client.";
      input {
        leaf lease-address-to-delete {
          type leafref {
            path "/dhcpv6-server/allocation-ranges/allocation-range/address-pools/address-pool/active-leases/active-lease/leased-address";
          }
          mandatory true;
          description
            "IPv6 address of an active lease that will be
deleted from the server.";
        }
      }

      output {
        leaf return-message {
          type string;
          description
            "Response message from the server.  If available, a
language identifier should be included in the message.";
          reference
            "BCP 18 (RFC 2277) IETF Policy on Character Sets
            and Languages, Section 4.2";

        }
      }
    }  // rpc delete-address-lease

    rpc delete-prefix-lease {
      nacm:default-deny-all;
      if-feature prefix-delegation;
      description
        "Deletes a client's active prefix lease from the server's
lease database.  Note that this will not cause the prefix
to be revoked from the client, and the lease may be refreshed
or renewed by the client.";
      input {
        leaf lease-prefix-to-delete {
          type leafref {
            path "/dhcpv6-server/allocation-ranges/allocation-range/prefix-pools/prefix-pool/active-leases/active-lease/leased-prefix";
          }
          mandatory true;
          description
            "IPv6 prefix of an active lease that will be deleted
from the server.";
        }
      }

      output {
        leaf return-message {
          type string;
          description
            "Response message from the server.  If available, a
language identifier should be included in the message.";
          reference
            "BCP 18 (RFC 2277) IETF Policy on Character Sets
            and Languages, Section 4.2";

        }
      }
    }  // rpc delete-prefix-lease

    notification address-pool-utilization-threshold-exceeded {
      if-feature na-assignment;
      description
        "Notification sent when the address pool
utilization exceeds the threshold configured in
max-address-utilization.";
      leaf pool-id {
        type leafref {
          path "/dhcpv6-server/allocation-ranges/allocation-range/address-pools/address-pool/pool-id";
        }
        mandatory true;
        description
          "Leafref to the address pool that the notification is being
generated for.";
      }

      leaf total-pool-addresses {
        type uint64;
        mandatory true;
        description
          "Total number of addresses in the pool (end-address minus
start-address plus one).";
      }

      leaf max-allocated-addresses {
        type uint64;
        mandatory true;
        description
          "Maximum number of addresses that can be simultaneously
allocated from the pool.  This value may be less than the
count of total addresses.  Calculated as the
max-address-utilization (percentage) of the
total-pool-addresses and rounded up.";
      }

      leaf allocated-address-count {
        type uint64;
        mandatory true;
        description
          "Number of addresses allocated from the pool.";
      }
    }  // notification address-pool-utilization-threshold-exceeded

    notification prefix-pool-utilization-threshold-exceeded {
      if-feature prefix-delegation;
      description
        "Notification sent when the prefix pool utilization
exceeds the threshold configured in
max-pd-space-utilization.";
      leaf pool-id {
        type leafref {
          path "/dhcpv6-server/allocation-ranges/allocation-range/prefix-pools/prefix-pool/pool-id";
        }
        mandatory true;
        description
          "Unique identifier for the pool.";
      }

      leaf total-pool-prefixes {
        type uint64;
        mandatory true;
        description
          "Total number of prefixes in the pool.";
      }

      leaf max-allocated-prefixes {
        type uint64;
        mandatory true;
        description
          "Maximum number of prefixes that can be simultaneously
allocated from the pool.  This value may be less than
the count of total prefixes.  Calculated as the
max-prefix-utilization (percentage) of the
total-pool-prefixes and rounded up.";
      }

      leaf allocated-prefixes-count {
        type uint64;
        mandatory true;
        description
          "Number of prefixes allocated from the pool.";
      }
    }  // notification prefix-pool-utilization-threshold-exceeded

    notification invalid-client-detected {
      description
        "Notification sent when the server detects an invalid
client.";
      leaf message-type {
        type enumeration {
          enum "solicit" {
            value 0;
            description
              "Solicit (1) message.";
          }
          enum "request" {
            value 1;
            description
              "Request (3) message.";
          }
          enum "confirm" {
            value 2;
            description
              "Confirm (4) message.";
          }
          enum "renew" {
            value 3;
            description "Renew (5) message.";
          }
          enum "rebind" {
            value 4;
            description
              "Rebind (6) message.";
          }
          enum "release" {
            value 5;
            description
              "Release (8) message.";
          }
          enum "decline" {
            value 6;
            description
              "Decline (9) message.";
          }
          enum "info-request" {
            value 7;
            description
              "Information request (11) message.";
          }
        }
        description
          "The message type received by the server that has caused
the error.";
      }

      leaf duid {
        type dhc6:duid;
        description "Client DUID.";
      }

      leaf description {
        type string;
        description
          "Description of the event (e.g., an error code or log
message).";
      }
    }  // notification invalid-client-detected

    notification decline-received {
      if-feature na-assignment;
      description
        "Notification sent when the server has received a Decline (9)
message from a client.";
      leaf duid {
        type dhc6:duid;
        description "Client DUID.";
      }

      list declined-resources {
        description
          "List of declined addresses and/or prefixes.";
        choice resource-type {
          description
            "Type of resource that has been declined.";
          leaf address {
            type inet:ipv6-address;
            description
              "Address that has been declined.";
          }
          leaf prefix {
            type inet:ipv6-prefix;
            description
              "Prefix that has been declined.";
          }
        }  // choice resource-type
      }  // list declined-resources
    }  // notification decline-received

    notification non-success-code-sent {
      description
        "Notification sent when the server responded to a client with
a non-success status code.";
      leaf duid {
        type dhc6:duid;
        description "Client DUID.";
      }

      uses dhc6:status;
    }  // notification non-success-code-sent
  }  // module ietf-dhcpv6-server