module bbf-icmpv6 {

    yang-version 1.1;

    namespace "urn:bbf:yang:bbf-icmpv6";

    prefix bbf-icmpv6;

    import ietf-interfaces {
      prefix if;
    }
    import ietf-yang-types {
      prefix yang;
    }
    import bbf-if-type {
      prefix bbfift;
    }
    import bbf-icmpv6-profile-common {
      prefix bbf-icmpv6-pc;
    }

    organization
      "Broadband Forum <https://www.broadband-forum.org>
     Common YANG Work Area";

    contact
      "Comments or questions about this Broadband Forum YANG module
     should be directed to <mailto:help@broadband-forum.org>.

     Editor:      Nick Hancock, Adtran

     Editor:      Ludwig Pauwels, Nokia

     PS Leader:   Joey Boyd, Adtran

     WA Director: Joey Boyd, Adtran

     WA Director: Sven Ooghe, Nokia";

    description
      "This module contains a collection of YANG definitions for
     supporting the Broadband Forum requirements on subscriber
     management via the Internet Control Message Protocol version 6
     (ICMPv6) as applicable to access network equipment. As such, this
     module is specific to access network equipment (e.g.,
     BBF-specified Access Nodes and FTTdp DPUs).

     The functionality to realize BBF's ICMPv6 protocol requirements
     is called 'ICMPv6 Relay'.

     Copyright (c) 2017-2023, Broadband Forum

     Redistribution and use in source and binary forms, with or
     without modification, are permitted provided that the following
     conditions are met:

     1. Redistributions of source code must retain the above copyright
        notice, this list of conditions and the following disclaimer.

     2. Redistributions in binary form must reproduce the above
        copyright notice, this list of conditions and the following
        disclaimer in the documentation and/or other materials
        provided with the distribution.

     3. Neither the name of the copyright holder nor the names of its
        contributors may be used to endorse or promote products
        derived from this software without specific prior written
        permission.

     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
     CONTRIBUTORS \"AS IS\" AND ANY EXPRESS OR IMPLIED WARRANTIES,
     INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
     MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
     CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
     CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
     STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
     ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

     The above license is used as a license under copyright only.
     Please reference the Forum IPR Policy for patent licensing terms
     <https://www.broadband-forum.org/ipr-policy>.

     Any moral rights which are necessary to exercise under the above
     license grant are also deemed granted under this license.

     This version of this YANG module is part of TR-383a7; see
     the TR itself for full legal notices.";

    revision "2023-12-15" {
      description
        "Amendment 7.
       * Approval Date:    2023-12-15.
       * Publication Date: 2023-12-15.";
      reference
        "TR-383a7: Common YANG Modules
        	  <https://www.broadband-forum.org/technical/download/
        		   TR-383_Amendment-7.pdf>";

    }


    grouping counters {
      description
        "Defines counter parameters.";
      leaf forwarded-messages {
        type yang:counter32;
        description
          "Number of messages forwarded.";
      }

      leaf discarded-messages {
        type yang:counter32;
        description
          "Number of messages discarded.";
      }
    }  // grouping counters

    grouping icmpv6-counters {
      description
        "Defines ICMPv6 statistics parameters.";
      container router-solicitation {
        description
          "ICMPv6 Router Solicitation statistics.";
        reference
          "TR-177 R-17";

        uses counters;
      }  // container router-solicitation

      container router-advertisement {
        description
          "ICMPv6 Router Advertisement statistics.";
        reference
          "TR-177 R-18";

        uses counters;
      }  // container router-advertisement

      container neighbor-advertisement {
        description
          "ICMPv6 Neighbor Advertisement statistics.";
        reference
          "TR-177 Section 5.6.2.4";

        uses counters;
      }  // container neighbor-advertisement

      container neighbor-solicitation {
        description
          "ICMPv6 Neighbor Solicitation statistics.";
        reference
          "TR-177 Section 5.6.2.3";

        uses counters;
      }  // container neighbor-solicitation

      container router-redirect {
        description
          "ICMPv6 Redirect Message statistics.";
        reference
          "TR-177 R-19";

        uses counters;
      }  // container router-redirect

      container multicast-listener-query {
        description
          "ICMPv6 Multicast Listener Query statistics.";
        reference
          "TR-177 R-20";

        uses counters;
      }  // container multicast-listener-query

      container error-message {
        description
          "Aggregate count of the following ICMPv6 error messages:
         Type 1 - Destination Unreachable
         Type 2 - Message Too Big
         Type 3 - Time Exceeded
         Type 4 - Parameter Problem.";
        reference
          "TR-177 Section 5.6.2";

        uses counters;
      }  // container error-message

      container informational-message {
        description
          "Aggregate count of the following ICMPv6 informational
         messages:
         Type 128 - Echo Request
         Type 129 - Echo Reply.";
        reference
          "TR-177 Section 5.6.2";

        uses counters;
      }  // container informational-message

      container unknown-message {
        description
          "ICMPv6 invalid message statistics, i.e., ICMPv6 messages with
         an unknown type.";
        reference
          "TR-177 R-13";

        uses counters;
      }  // container unknown-message
    }  // grouping icmpv6-counters

    uses bbf-icmpv6-pc:icmpv6-profiles;

    augment /if:interfaces/if:interface {
      when
        "derived-from-or-self (if:type, 'bbfift:vlan-sub-interface')" {
        description
          "Applies to VLAN sub-interfaces.";
      }
      description
        "Additions for ICMPv6 message processing on the VLAN
       sub-interface.";
      container icmpv6 {
        presence
          "Indicates configuration related to ICMPv6 message processing
         is present on this interface.";
        description
          "ICMPv6 Relay configuration parameters.

         Configuration within this container instantiates (or may
         instantiate, see leaf 'enabled') an ICMPv6 Relay with a
         behavior based on the additional configuration contained
         within this container.

         If the container is not present, no ICMPv6 Relay
         functionality is performed on this interface. Any received
         ICMPv6 message is processed based on the layer 2
         configuration, e.g., VLAN sub-interface and/or layer 2
         forwarding.";
        leaf enabled {
          type union {
            type boolean;
            type enumeration {
              enum "secured-host" {
                value 0;
                description
                  "Upstream ICMPv6 messages that can be sent by a host
                 are forwarded. Messages that can be sent only by a
                 router are discarded. Discarded messages are:
                 - Router Advertisement
                 - Redirect
                 - MLD query messages.

                 Downstream ICMPv6 messages that could reveal data of
                 one user to another shall be sent to the right user
                 only or shall be discarded. For example, the
                 multicast Neighbor Solicitation message sent to
                 resolve a user's IP address to a MAC address shall be
                 discarded.";
              }
            }
          }
          default "false";
          description
            "If 'true', the ICMPv6 Relay will process ICMPv6 messages
           received on the interface as defined in the referenced
           Technical Report:
           - Discard messages that are only sent by routers, i.e.,
             Router Advertisement, Redirect, MLD Query messages.
           - Relay the received Router Solicitation within a new IPv6
             datagram and insert a LIO.
           - Forward other ICMPv6 messages as normal layer 2 frames.

           The downstream IPv6 datagram received as a reply will be
           unpacked and the Router Advertisement message included
           within will be sent on the interface identified by the LIO.

           Downstream ICMPv6 messages that can come from a router are
           forwarded, Downstream ICMPv6 messages that can come only
           from a host, i.e., the Router Solicitation message, shall
           be discarded (if it reaches the VLAN sub-interface).

           If 'false', no ICMPv6 Relay functionality is performed on
           this interface. Received ICMPv6 messages are processed
           based on the layer 2 configuration, e.g., VLAN
           sub-interface and/or layer 2 forwarding.

           Otherwise, the ICMPv6 Relay will forward messages as
           defined in the selected enumeration.";
          reference
            "TR-177 R-17;
            TR-177 R-18;
            TR-177 R-19;
            TR-177 R-20";

        }

        leaf unknown-type-processing {
          type enumeration {
            enum "forward" {
              value 0;
              description
                "ICMPv6 messages with a type unknown to the device are
               processed based on the layer 2 forwarding
               configuration.";
            }
            enum "discard" {
              value 1;
              description
                "ICMPv6 messages with a type unknown to the device are
               discarded.";
            }
          }
          default "forward";
          description
            "Manages how to process ICMPv6 messages with a type unknown
           to the device.";
          reference
            "TR-177 R-13";

        }

        leaf profile-ref {
          when "../enabled = 'true'" {
            description
              "Applicable only when ICMPv6 Relay functionality is
             enabled.";
          }
          if-feature bbf-icmpv6-pc:relay-with-lio;
          type leafref {
            path "/bbf-icmpv6:icmpv6-profiles/bbf-icmpv6:icmpv6-profile/bbf-icmpv6:name";
          }
          mandatory true;
          description
            "Reference to the ICMPv6 configuration profile.";
        }
      }  // container icmpv6
    }

    augment /if:interfaces-state/if:interface/if:statistics {
      when
        "derived-from-or-self (../if:type, "
          + "                      'bbfift:vlan-sub-interface')" {
        description
          "Applies only to VLAN sub-interfaces.";
      }
      description
        "Add state data for ICMPv6 message processing statistics on
       VLAN sub-interfaces.

       Note that the model provides a rather complete set of optional
       statistics. This does not turn the support of these statistics
       into a requirement. For example, if certain ICMPv6 messages are
       forwarded at layer 2 then such messages might not be counted.";
      container icmpv6 {
        presence
          "ICMPv6 statistics are available.";
        description
          "Container presents the message statistics related to the
         ICMPv6 Relay.";
        container upstream {
          description
            "Upstream ICMPv6 Relay statistics.";
          uses icmpv6-counters;
        }  // container upstream

        container downstream {
          description
            "Downstream ICMPv6 Relay statistics.";
          uses icmpv6-counters;
        }  // container downstream
      }  // container icmpv6
    }
  }  // module bbf-icmpv6