module ietf-dots-signal-channel {

    yang-version 1.1;

    namespace
      "urn:ietf:params:xml:ns:yang:ietf-dots-signal-channel";

    prefix signal;

    import ietf-inet-types {
      prefix inet;
      reference
        "Section 4 of RFC 6991";


    }
    import ietf-yang-types {
      prefix yang;
      reference
        "Section 3 of RFC 6991";


    }
    import ietf-dots-data-channel {
      prefix ietf-data;
      reference
        "RFC 8783: Distributed Denial-of-Service Open Threat Signaling
        	  (DOTS) Data Channel Specification";


    }
    import iana-dots-signal-channel {
      prefix iana-signal;
    }

    organization
      "IETF DDoS Open Threat Signaling (DOTS) Working Group";

    contact
      "WG Web:   <https://datatracker.ietf.org/wg/dots/>
     WG List:  <mailto:dots@ietf.org>

     Editor:  Konda, Tirumaleswar Reddy.K
              <mailto:TirumaleswarReddy_Konda@McAfee.com>

     Editor:  Mohamed Boucadair
              <mailto:mohamed.boucadair@orange.com>

     Author:  Prashanth Patil
              <mailto:praspati@cisco.com>

     Author:  Andrew Mortensen
              <mailto:amortensen@arbor.net>

     Author:  Nik Teague
              <mailto:nteague@ironmountain.co.uk>";

    description
      "This module contains YANG definition for the signaling
     messages exchanged between a DOTS client and a DOTS server.

     Copyright (c) 2020 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 8782; see
     the RFC itself for full legal notices.";

    revision "2020-05-28" {
      description "Initial revision.";
      reference
        "RFC 8782: Distributed Denial-of-Service Open Threat
        	  Signaling (DOTS) Signal Channel Specification";

    }


    grouping mitigation-scope {
      description
        "Specifies the scope of the mitigation request.";
      list scope {
        key "cuid mid";
        description
          "The scope of the request.";
        leaf cdid {
          type string;
          description
            "The cdid should be included by a server-domain
           DOTS gateway to propagate the client domain
           identification information from the
           gateway's client-facing side to the gateway's
           server-facing side, and from the gateway's
           server-facing side to the DOTS server.

           It may be used by the final DOTS server
           for policy enforcement purposes.";
        }

        leaf cuid {
          type string;
          description
            "A unique identifier that is
           generated by a DOTS client to prevent
           request collisions.  It is expected that the
           cuid will remain consistent throughout the
           lifetime of the DOTS client.";
        }

        leaf mid {
          type uint32;
          description
            "Mitigation request identifier.

           This identifier must be unique for each mitigation
           request bound to the DOTS client.";
        }

        uses ietf-data:target;

        leaf-list alias-name {
          type string;
          description
            "An alias name that points to a resource.";
        }

        leaf lifetime {
          type int32;
          units "seconds";
          default "3600";
          description
            "Indicates the lifetime of the mitigation request.

           A lifetime of '0' in a mitigation request is an
           invalid value.

           A lifetime of negative one (-1) indicates indefinite
           lifetime for the mitigation request.";
        }

        leaf trigger-mitigation {
          type boolean;
          default "true";
          description
            "If set to 'false', DDoS mitigation will not be
           triggered unless the DOTS signal channel
           session is lost.";
        }

        leaf mitigation-start {
          type uint64;
          config false;
          description
            "Mitigation start time is represented in seconds
           relative to 1970-01-01T00:00:00Z in UTC time.";
        }

        leaf status {
          type iana-signal:status;
          config false;
          description
            "Indicates the status of a mitigation request.
           It must be included in responses only.";
        }

        container conflict-information {
          config false;
          description
            "Indicates that a conflict is detected.
           Must only be used for responses.";
          leaf conflict-status {
            type iana-signal:conflict-status;
            description
              "Indicates the conflict status.";
          }

          leaf conflict-cause {
            type iana-signal:conflict-cause;
            description
              "Indicates the cause of the conflict.";
          }

          leaf retry-timer {
            type uint32;
            units "seconds";
            description
              "The DOTS client must not resend the
             same request that has a conflict before the expiry of
             this timer.";
          }

          container conflict-scope {
            description
              "Provides more information about the conflict scope.";
            uses ietf-data:target {
              when
                "/dots-signal/scope/conflict-information/"
                  + "conflict-cause = 'overlapping-targets'";
            }

            leaf-list alias-name {
              when
                "../../conflict-cause = 'overlapping-targets'";
              type string;
              description
                "Conflicting alias-name.";
            }

            list acl-list {
              when
                "../../conflict-cause = 'conflict-with-acceptlist'";
              key "acl-name";
              description
                "List of conflicting ACLs as defined in the DOTS data
               channel.  These ACLs are uniquely defined by
               cuid and acl-name.";
              leaf acl-name {
                type leafref {
                  path
                    "/ietf-data:dots-data/ietf-data:dots-client/"
                      + "ietf-data:acls/ietf-data:acl/ietf-data:name";
                }
                description
                  "Reference to the conflicting ACL name bound to
                 a DOTS client.";
              }

              leaf acl-type {
                type leafref {
                  path
                    "/ietf-data:dots-data/ietf-data:dots-client/"
                      + "ietf-data:acls/ietf-data:acl/ietf-data:type";
                }
                description
                  "Reference to the conflicting ACL type bound to
                 a DOTS client.";
              }
            }  // list acl-list

            leaf mid {
              when
                "../../conflict-cause = 'overlapping-targets'";
              type leafref {
                path "../../../mid";
              }
              description
                "Reference to the conflicting 'mid' bound to
               the same DOTS client.";
            }
          }  // container conflict-scope
        }  // container conflict-information

        leaf bytes-dropped {
          type yang:zero-based-counter64;
          units "bytes";
          config false;
          description
            "The total dropped byte count for the mitigation
           request since the attack mitigation was triggered.
           The count wraps around when it reaches the maximum value
           of counter64 for dropped bytes.";
        }

        leaf bps-dropped {
          type yang:gauge64;
          config false;
          description
            "The average number of dropped bits per second for
           the mitigation request since the attack
           mitigation was triggered.  This should be over
           five-minute intervals (that is, measuring bytes
           into five-minute buckets and then averaging these
           buckets over the time since the mitigation was
           triggered).";
        }

        leaf pkts-dropped {
          type yang:zero-based-counter64;
          config false;
          description
            "The total number of dropped packet count for the
           mitigation request since the attack mitigation was
           triggered.  The count wraps around when it reaches
           the maximum value of counter64 for dropped packets.";
        }

        leaf pps-dropped {
          type yang:gauge64;
          config false;
          description
            "The average number of dropped packets per second
           for the mitigation request since the attack
           mitigation was triggered.  This should be over
           five-minute intervals (that is, measuring packets
           into five-minute buckets and then averaging these
           buckets over the time since the mitigation was
           triggered).";
        }

        leaf attack-status {
          type iana-signal:attack-status;
          description
            "Indicates the status of an attack as seen by the
           DOTS client.";
        }
      }  // list scope
    }  // grouping mitigation-scope

    grouping config-parameters {
      description
        "Subset of DOTS signal channel session configuration.";
      container heartbeat-interval {
        description
          "DOTS agents regularly send heartbeats to each other
         after mutual authentication is successfully
         completed in order to keep the DOTS signal channel
         open.";
        leaf max-value {
          type uint16;
          units "seconds";
          config false;
          description
            "Maximum acceptable heartbeat-interval value.";
        }

        leaf min-value {
          type uint16;
          units "seconds";
          config false;
          description
            "Minimum acceptable heartbeat-interval value.";
        }

        leaf current-value {
          type uint16;
          units "seconds";
          default "30";
          description
            "Current heartbeat-interval value.

           '0' means that heartbeat mechanism is deactivated.";
        }
      }  // container heartbeat-interval

      container missing-hb-allowed {
        description
          "Maximum number of missing heartbeats allowed.";
        leaf max-value {
          type uint16;
          config false;
          description
            "Maximum acceptable missing-hb-allowed value.";
        }

        leaf min-value {
          type uint16;
          config false;
          description
            "Minimum acceptable missing-hb-allowed value.";
        }

        leaf current-value {
          type uint16;
          default "15";
          description
            "Current missing-hb-allowed value.";
        }
      }  // container missing-hb-allowed

      container probing-rate {
        description
          "The limit for sending Non-confirmable messages with
         no response.";
        leaf max-value {
          type uint16;
          units "byte/second";
          config false;
          description
            "Maximum acceptable probing-rate value.";
        }

        leaf min-value {
          type uint16;
          units "byte/second";
          config false;
          description
            "Minimum acceptable probing-rate value.";
        }

        leaf current-value {
          type uint16;
          units "byte/second";
          default "5";
          description
            "Current probing-rate value.";
        }
      }  // container probing-rate

      container max-retransmit {
        description
          "Maximum number of retransmissions of a Confirmable
         message.";
        leaf max-value {
          type uint16;
          config false;
          description
            "Maximum acceptable max-retransmit value.";
        }

        leaf min-value {
          type uint16;
          config false;
          description
            "Minimum acceptable max-retransmit value.";
        }

        leaf current-value {
          type uint16;
          default "3";
          description
            "Current max-retransmit value.";
        }
      }  // container max-retransmit

      container ack-timeout {
        description
          "Initial retransmission timeout value.";
        leaf max-value-decimal {
          type decimal64 {
            fraction-digits 2;
          }
          units "seconds";
          config false;
          description
            "Maximum ack-timeout value.";
        }

        leaf min-value-decimal {
          type decimal64 {
            fraction-digits 2;
          }
          units "seconds";
          config false;
          description
            "Minimum ack-timeout value.";
        }

        leaf current-value-decimal {
          type decimal64 {
            fraction-digits 2;
          }
          units "seconds";
          default "2";
          description
            "Current ack-timeout value.";
        }
      }  // container ack-timeout

      container ack-random-factor {
        description
          "Random factor used to influence the timing of
         retransmissions.";
        leaf max-value-decimal {
          type decimal64 {
            fraction-digits 2;
          }
          config false;
          description
            "Maximum acceptable ack-random-factor value.";
        }

        leaf min-value-decimal {
          type decimal64 {
            fraction-digits 2;
          }
          config false;
          description
            "Minimum acceptable ack-random-factor value.";
        }

        leaf current-value-decimal {
          type decimal64 {
            fraction-digits 2;
          }
          default "1.5";
          description
            "Current ack-random-factor value.";
        }
      }  // container ack-random-factor
    }  // grouping config-parameters

    grouping signal-config {
      description
        "DOTS signal channel session configuration.";
      leaf sid {
        type uint32;
        mandatory true;
        description
          "An identifier for the DOTS signal channel
         session configuration data.";
      }

      container mitigating-config {
        description
          "Configuration parameters to use when a mitigation
         is active.";
        uses config-parameters;
      }  // container mitigating-config

      container idle-config {
        description
          "Configuration parameters to use when no mitigation
         is active.";
        uses config-parameters;
      }  // container idle-config
    }  // grouping signal-config

    grouping redirected-signal {
      description
        "Grouping for the redirected signaling.";
      leaf alt-server {
        type string;
        config false;
        mandatory true;
        description
          "FQDN of an alternate server.";
      }

      leaf-list alt-server-record {
        type inet:ip-address;
        config false;
        description
          "List of records for the alternate server.";
      }
    }  // grouping redirected-signal

    container dots-signal {
      description
        "Main container for DOTS signal message.

       A DOTS signal message can be a mitigation, a configuration,
       or a redirected signal message.";
      choice message-type {
        description
          "Can be a mitigation, a configuration, or a redirect
         message.";
        case mitigation-scope {
          description
            "Mitigation scope of a mitigation message.";
          uses mitigation-scope;
        }  // case mitigation-scope

        case signal-config {
          description
            "Configuration message.";
          uses signal-config;
        }  // case signal-config

        case redirected-signal {
          description
            "Redirected signaling.";
          uses redirected-signal;
        }  // case redirected-signal

        case heartbeat {
          description "DOTS heartbeats.";
          leaf peer-hb-status {
            type boolean;
            mandatory true;
            description
              "Indicates whether a DOTS agent receives heartbeats
             from its peer.  The value is set to 'true' if the
             DOTS agent is receiving heartbeat messages
             from its peer.";
          }
        }  // case heartbeat
      }  // choice message-type
    }  // container dots-signal
  }  // module ietf-dots-signal-channel