path: root/src/plugins/yang/openconfig/openconfig-bfd.yang

module openconfig-bfd {

  yang-version "1";

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

  prefix "oc-bfd";

  // import some basic types
  import openconfig-extensions { prefix "ocext"; }
  import openconfig-types { prefix "oc-types"; }
  import openconfig-interfaces { prefix "oc-if"; }
  import openconfig-inet-types { prefix "oc-inet"; }
  import openconfig-if-types { prefix "oc-ift"; }
  import openconfig-network-instance { prefix "oc-ni"; }
  import openconfig-policy-types { prefix "oc-pol-types"; }

  // meta
  organization "OpenConfig working group";

  contact
    "OpenConfig working group
    www.openconfig.net";

  description
    "An OpenConfig model of Bi-Directional Forwarding Detection (BFD)
    configuration and operational state.";

  ocext:openconfig-version "0.1.0";

  revision "2017-11-17" {
    description
      "Update version number for initial sharing.";
    reference "0.1.0";
  }

  revision "2017-10-19" {
    description
      "Adopt OpenConfig types models, type corrections";
    reference "0.0.2";
  }

  revision "2016-06-24" {
    description
      "Initial revision";
    reference "0.0.1";
  }

  typedef bfd-session-state {
    type enumeration {
      enum UP {
        description
          "The BFD session is perceived to be up by the system.";
      }
      enum DOWN {
        description
          "The BFD session is perceived to be down by the system.";
      }
      enum ADMIN_DOWN {
        description
          "The BFD session is administratively disabled.";
      }
      enum INIT {
        description
          "The BFD session is perceived to be initialising by the
          system.";
      }
    }
    description
      "The state of the BFD session according to the system referred
      to by the context of the leaf.";
    reference
      "RFC5880 - Bidirectional Forwarding Detection, Section
      4.1";
  }

  typedef bfd-diagnostic-code {
    type enumeration {
      enum NO_DIAGNOSTIC {
        value 0;
        description
          "No diagnostic code was specified, or the session has not
          changed state.";
      }
      enum DETECTION_TIMEOUT {
        value 1;
        description
          "The control detection time expired: no BFD packet was
          received within the required period.";
      }
      enum ECHO_FAILED {
        value 2;
        description
          "The BFD echo function failed - echo packets have not been
          received for the required period of time.";
      }
      enum FORWARDING_RESET {
        value 3;
        description
          "The forwarding plane in the local system was reset - such
          that the remote system cannot rely on the forwarding state of
          the device specifying this error code.";
      }
      enum PATH_DOWN {
        value 4;
        description
          "Signalling outside of BFD specified that the path underlying
          this session has failed.";
      }
      enum CONCATENATED_PATH_DOWN {
        value 5;
        description
          "When a BFD session runs over a series of path segments, this
          error code indicates that a subsequent path segment (i.e.,
          one in the transmit path between the source and destination
          of the session) has failed.";
      }
      enum ADMIN_DOWN {
        value 6;
        description
          "The BFD session has been administratively disabled by the
          peer.";
      }
      enum REVERSE_CONCATENATED_PATH_DOWN {
        value 7;
        description
          "In the case that a BFD session is running over a series of
          path segments, this error code indicates that a path segment
          on the reverse path (i.e., in the transmit direction from the
          destination to the source of the session) has failed.";
      }
    }
    description
      "Diagnostic codes defined by BFD. These typically indicate the
      reason for a change of session state.";
    reference
      "RFC5880 - Bidirectional Forwarding Detection, Section
      4.1";
  }


  grouping bfd-interface-config {
    description
      "Top-level per-interface configuration parameters for BFD.";

    leaf id {
      type string;
      description
        "A unique identifier for the interface.";
    }

    leaf enabled {
      type boolean;
      description
        "When this leaf is set to true then the BFD session is enabled
        on the specified interface - if it is set to false, it is
        administratively disabled.";
    }

    leaf local-address {
      type oc-inet:ip-address;
      description
        "The source IP address to be used for BFD sessions over this
        interface.";
    }

    leaf desired-minimum-tx-interval {
      type uint32;
      units microseconds;
      description
        "The minimum interval between transmission of BFD control
        packets that the operator desires. This value is advertised to
        the peer, however the actual interval used is specified by
        taking the maximum of desired-minimum-tx-interval and the
        value of the remote required-minimum-receive interval value.

        This value is specified as an integer number of microseconds.";
    }

    leaf required-minimum-receive {
      type uint32;
      units microseconds;
      description
        "The minimum interval between received BFD control packets that
        this system should support. This value is advertised to the
        remote peer to indicate the maximum frequency (i.e., minimum
        inter-packet interval) between BFD control packets that is
        acceptable to the local system.";
    }

    // rjs: Could have required-minimum-echo-receive here, but this is
    // generally not configurable.

    leaf detection-multiplier {
      type uint16 {
        range "1..max";
      }
      description
        "The number of packets that must be missed to declare this
        session as down. The detection interval for the BFD session
        is calculated by multiplying the value of the negotiated
        transmission interval by this value.";
    }

    leaf enable-per-member-link {
      type boolean;
      default false;
      description
        "When this leaf is set to true - BFD will be enabled on
        each member interface of the aggregated Ethernet bundle.";

      when "/oc-if:interfaces/oc-if:interface" +
          "[name=current()/../../interface-ref/config/interface]/" +
          "oc-if:state/oc-if:type = 'oc-ift:IF_AGGREGATE'" {
        description
          "Include per-member link BFD only when the type of
          interface is a link aggregate.";
      }
    }
  }

  grouping bfd-interface-state {
    // placeholder
    description
      "Operational state parameters relating to BFD running on an
      interface.";
  }

  grouping bfd-session-state-mode-timers-common {
    description
      "Common operational state parameters that are re-used across
      both asynchronous and echo modes of BFD.";

    leaf last-packet-transmitted {
      type uint64;
      description
        "The date and time at which the last BFD packet
        was transmitted for this session, expressed as the number
        of nanoseconds since the Unix Epoch (January 1, 1970,
        00:00 UTC).";
    }

    leaf last-packet-received {
      type uint64;
      description
        "The date and time at which the last BFD packet
        was received for this session, expressed as the number
        of nanoseconds since the Unix Epoch (January 1, 1970,
        00:00 UTC).";
    }

    leaf transmitted-packets {
      // TODO: looks to be unsupported on JUNOS
      type uint64;
      description
        "The number of packets that have been transmitted
        by the local system.";
    }

    leaf received-packets {
      // TODO: looks to be unsupported on JUNOS
      type uint64;
      description
        "The number of packets that have been received by the
        local system from the remote neighbour.";
    }

    leaf up-transitions {
      // TODO: looks to only be supported in SROS
      type uint64;
      description
        "The number of times that the adjacency with the neighbor
        has transitioned into the up state.";
    }
  }

  grouping bfd-session-state-sessiondetails-common {
    description
      "Common session details for a BFD session.";

    leaf session-state {
      type bfd-session-state;
      description
        "The state of the BFD session perceived by the local system.";

    }

    leaf remote-session-state {
      type bfd-session-state;
      description
        "The reported state of the BFD session according to the remote
        system. This state reflects the last state reported in a BFD
        control packet.";
    }

    leaf last-failure-time {
      type oc-types:timeticks64;
      description
        "The time of the last transition of the BFD session out of
        the UP state, expressed as the number of nanoseconds since
        the Unix epoch.";
    }

    leaf failure-transitions {
      type uint64;
      description
        "The number of times that the BFD session has transitioned
        out of the UP state.";
    }

    leaf local-discriminator {
      type string;
      description
        "A unique identifier used by the local system to identify this
        BFD session.";
    }

    leaf remote-discriminator {
      type string;
      description
        "A unique identified used by the remote system to identify this
        BFD session.";
    }

    leaf local-diagnostic-code {
      type bfd-diagnostic-code;
      description
        "The local BFD diagnostic code indicating the most recent
        reason for failure of this BFD session.";
    }

    leaf remote-diagnostic-code {
      type bfd-diagnostic-code;
      description
        "The remote BFD diagnostic code indicating the remote system's
        reason for failure of the BFD session";
    }

    leaf remote-minimum-receive-interval {
      type uint32;
      description
        "The value of the minimum receive interval that was specified
        in the most recent BFD control packet received from the peer.";
    }

    leaf demand-mode-requested {
      type boolean;
      description
        "This leaf is set to true when the remote system has requested
        demand mode be run for this session.";
    }

    leaf remote-authentication-enabled {
      type boolean;
      description
        "This leaf is set to true when the remote system has specified
        that authentication is present for the BFD session.";
    }

    leaf remote-control-plane-independent {
      type boolean;
      description
        "This leaf is set to true when the remote system has specified
        that the hardware implementing this BFD session is independent
        of the control plane's liveliness.";
    }
  }


  grouping bfd-session-state-async-common {
    description
      "Common parameters for asynchronous BFD sessions";

    container async {
      description
        "Operational state parameters specifically relating to
        asynchronous mode of BFD.";

      uses bfd-session-state-mode-timers-common;
    }
  }

  grouping bfd-session-state-echo-common {
    description
      "Common parameters for echo-mode BFD sessions.";

    container echo {
      description
        "Operational state parameters specifically relating to the
        echo mode of BFD.";

      leaf active {
        type boolean;
        description
          "This leaf is set to true when echo mode is running between
          the local and remote system. When it is set to false, solely
          asynchronous mode is active.";
      }

      uses bfd-session-state-mode-timers-common;
    }
  }


  grouping bfd-session-state-common {
    description
      "Common operational state parameters that may be re-used across
      multiple BFD session contexts.";

    leaf local-address {
      type oc-inet:ip-address;
      description
        "The IP address used by the local system for this BFD session.";
    }

    leaf remote-address {
      type oc-inet:ip-address;
      description
        "The IP address used by the remote system for this BFD session.";
    }

    leaf-list subscribed-protocols {
      type identityref {
        base "oc-pol-types:INSTALL_PROTOCOL_TYPE";
      }
      description
        "Indicates the set of protocols that currently use
        this BFD session for liveliness detection.";
    }

    uses bfd-session-state-sessiondetails-common;
    uses bfd-session-state-echo-common;
    uses bfd-session-state-async-common;
  }

  grouping bfd-session-microbfd-common {
    description
      "BFD session parameters utilised only for micro-BFD sessions.";

    uses bfd-session-state-sessiondetails-common;
    uses bfd-session-state-async-common;
  }

  grouping bfd-interface-peer-state {
    description
      "Per-peer, per-interface operational state parameters for BFD.";

    uses bfd-session-state-common;
  }

  grouping bfd-interface-microbfd-config {
    description
      "Configuration parameters for a microBFD session on an
      interface.";

    leaf local-address {
      type oc-inet:ip-address;
      description
        "The local IP address used by the system for the micro-BFD session
        specified.";
    }

    leaf remote-address {
      type oc-inet:ip-address;
      description
        "The remote IP destination that should be used by the system for
        the micro-BFD session specified.";
    }

    leaf member-interface {
      type leafref {
        path "/oc-if:interfaces/" +
          "oc-if:interface/oc-if:config/oc-if:name";
      }
      // rjs: Note that this does not restrict to only interfaces that
      // are part of the current LAG. An implementation should return
      // NOK if such an interface is specified.
      description
        "Reference to a member link of the aggregate interface being
        described.";
    }
  }

  grouping bfd-interface-microbfd-state {
    description
      "Operational state parameters relating to a micro-BFD session on
      an interface.";

    uses bfd-session-microbfd-common;
  }

  grouping bfd-interface-microbfd-structural {
    description
      "Structural grouping for micro-bfd configuration and state
      parameters.";

    container micro-bfd-sessions {
      description
        "Parameters relating to micro-BFD sessions associated
        with the interface.";

      list micro-bfd-session {
        description
          "This list contains configuration and state parameters
          relating to micro-BFD session.";
        reference
          "RFC7130 - Bidirectional Forwarding Detection (BFD)
          on Link Aggregation Group (LAG) Interfaces.";

        key "member-interface";

        leaf member-interface {
          type leafref {
            path "../config/member-interface";
          }
          description
            "A reference to the member interface of the link
            aggregate.";
        }

        container config {
          description
            "Configuration parameters for the micro-BFD session.";
          uses bfd-interface-microbfd-config;
        }

        container state {
          config false;
          description
            "Operational state parameters for the micro-BFD session.";
          uses bfd-interface-microbfd-config;
          uses bfd-interface-microbfd-state;
        }
      }
      when "/oc-if:interfaces/oc-if:interface" +
          "[name=current()/../interface-ref/config/interface]/" +
          "oc-if:state/oc-if:type = 'oc-ift:IF_AGGREGATE'" {
        description
          "Include per-member link BFD only when the type of
          interface is a link aggregate.";
      }
    }
  }

  grouping bfd-interface-peer-structural {
    description
      "Structural grouping for BFD peers (in the context of an interface).";

    container peers {
      description
        "Parameters relating to the BFD peers which are seen
        over this interface.";

      list peer {
        key "local-discriminator";
        config false;

        description
          "Parameters relating to the BFD peer specified by the
          remote address.";

        leaf local-discriminator {
          type leafref {
            path "../state/local-discriminator";
          }
          description
            "The local discriminator, which is unique for the
            session on the system.";
        }

        container state {
          config false;
          description
            "Operational state parameters for the BFD session.";

          uses bfd-interface-peer-state;
        }
      }
    }
  }

  grouping bfd-top {
    description
      "Structural grouping for Bidirectional Forwarding Detection (BFD).";

    container bfd {
      description
        "Configuration and operational state parameters for BFD.";
      reference "RFC5880, RFC5881";

      container interfaces {
        description
          "Interfaces on which BFD sessions are to be enabled.";

        list interface {
          key "id";

          description
            "Per-interface configuration and state parameters for BFD.";

          leaf id {
            type leafref {
              path "../config/id";
            }
            description
              "A reference to an identifier for the interface on which
              BFD is enabled.";
          }

          container config {
            description
              "Configuration parameters for BFD on the specified
              interface.";
            uses bfd-interface-config;
          }

          container state {
            config false;
            description
              "Operational state parameters for BFD on the specified
              interface.";
            uses bfd-interface-config;
            uses bfd-interface-state;
          }

          uses oc-if:interface-ref;

          uses bfd-interface-microbfd-structural;
          uses bfd-interface-peer-structural;
        }
      }
    }
  }

  grouping enable-bfd-config {
    description
      "Configuration parameters relating to enabling BFD.";

    leaf enabled {
      type boolean;
      description
        "When this leaf is set to true, BFD is used to detect the
        liveliness of the remote peer or next-hop.";
    }
  }

  grouping enable-bfd-state {
    description
      "Operational state parameters relating to enabling BFD.";

    leaf associated-session {
      // TODO: this is a leafref to something unique, but seems
      // like it might be expensive for the NMS to find out since
      // it will need to cycle through all interfaces looking for
      // the associated local-discriminator.
      type leafref {
        path "/bfd/interfaces/interface/peers/peer/local-discriminator";
      }
      description
        "A reference to the BFD session that is tracking the liveliness
        of the remote entity.";
    }

    //
    // A fix to the above is to have the following leaf to show which
    // interface is associated.
    //
    // leaf associated-interface {
    //   type leafref {
    //     path "/bfd/interfaces/interface/config/id";
    //   }
    // }
  }

  grouping bfd-enable {
    description
      "Grouping which can be included in a protocol wishing to enable
      BFD.";

    container enable-bfd {
      description
        "Enable BFD for liveliness detection to the next-hop or
        neighbour.";

      container config {
        description
          "Configuration parameters relating to enabling BFD.";

        uses enable-bfd-config;
      }

      container state {
        config false;
        description
          "Operational state parameters relating to enabing BFD.";

        uses enable-bfd-config;
        uses enable-bfd-state;
      }
    }
  }

  // rjs - TODO - should these be specified within each model? The
  // answer here is probably yes, since otherwise openconfig
  // network-instance ends up with a circular reference.
  augment "/oc-ni:network-instances/oc-ni:network-instance/" +
          "oc-ni:protocols/oc-ni:protocol/oc-ni:bgp/" +
          "oc-ni:neighbors/oc-ni:neighbor" {
    description
      "Augment the BGP routing protocol to add a link to BFD for
      neighbour detection.";

    uses bfd-enable;
  }

  augment "/oc-ni:network-instances/oc-ni:network-instance/" +
          "oc-ni:protocols/oc-ni:protocol/oc-ni:bgp/" +
          "oc-ni:peer-groups/oc-ni:peer-group" {
    description
      "Augment the BGP routing protocol to add a link to BFD for
      neighbor detection when specified within a peer-group.";

    uses bfd-enable;
  }

  augment "/oc-ni:network-instances/oc-ni:network-instance/" +
          "oc-ni:protocols/oc-ni:protocol/oc-ni:static-routes/" +
          "oc-ni:static/oc-ni:next-hops/oc-ni:next-hop" {
    description
      "Augment the static route configuration to allow a next-hop
      to be tracked by BFD.";

    uses bfd-enable;
  }

  uses bfd-top;
}