module ietf-bmp-telemetry-message {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-bmp-telemetry-message";
  prefix bmptm;

  import ietf-inet-types {
    prefix inet;
    reference
      "RFC 9911: Common YANG Data Types";
  }
  import ietf-yang-types {
    prefix yang;
    reference
      "RFC 9911: Common YANG Data Types";
  }
  import ietf-yang-structure-ext {
    prefix sx;
    reference
      "RFC 8791: YANG Data Structure Extensions";
  }
  import ietf-routing-types {
    prefix rt-types;
    reference
      "RFC 8294: Common YANG Data Types for the Routing Area.";
  }
  import ietf-bgp-open {
    prefix bgo;
    reference
      "RFC XXXX: YANG Model for a BGP OPEN Message.";
  }
  import ietf-bgp-rib-entry {
    prefix bre;
    reference
      "RFC XXXX: YANG Model for a BGP RIB Entry.";
  }
  import ietf-bmp-tlv {
    prefix btlv;
    reference
      "RFC XXXX: YANG Model for BMP TLVs.";
  }

  organization
    "IETF Draft";
  contact
    "Author:    Thomas Graf
                <mailto:thomas.graf@swisscom.com>
                Paolo Lucente
                <mailto:paolo@ntt.net>
                Leonardo Rodoni
                <mailto:leonardo.rodoni@swisscom.com>";

  description
    "Adds BMP specific subscription metadata to the data collection
     protocol provenance of the ietf-telemetry-message envelope.

     The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL',
     'SHALL NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED',
     'NOT RECOMMENDED', 'MAY', and 'OPTIONAL' in this document
     are to be interpreted as described in BCP 14 (RFC 2119)
     (RFC 8174) when, and only when, they appear in all
     capitals, as shown here.

     Copyright (c) 2026 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 XXXX; see the RFC
     itself for full legal notices.";
  revision 2026-06-30 {
    description
      "Initial revision.";
    reference
      "RFC XXXX";
  }

  typedef peer-type {
    type enumeration {
      enum global-instance-peer {
        value 0;
        description
          "Global Instance Peer";
        reference
          "RFC 7854: BGP Monitoring Protocol (BMP), Section 4.2.";
      }
      enum rd-instance-peer {
        value 1;
        description
          "RD Instance Peer";
        reference
          "RFC 7854: BGP Monitoring Protocol (BMP), Section 4.2.";
      }
      enum local-instance-peer {
        value 2;
        description
          "Local Instance Peer";
        reference
          "RFC 7854: BGP Monitoring Protocol (BMP), Section 4.2.";
      }
      enum loc-rib-instance-peer {
        value 3;
        description
          "Loc-RIB Instance Peer";
        reference
          "RFC 9069: Support for Local RIB in the BGP Monitoring
           Protocol (BMP)";
      }
    }
    description
      "BMP Peer Type.";
    reference
      "RFC 7854: BGP Monitoring Protocol (BMP), Section 4.2.";
  }

  grouping per-peer {
    description
      "BMP per-peer header.";
    reference
      "RFC 7854: BGP Monitoring Protocol (BMP), Section 4.2.";
    leaf peer-type {
      type peer-type;
      mandatory true;
      description
        "BMP peer type from per-peer header.";
      reference
        "RFC 7854: BGP Monitoring Protocol (BMP), Section 4.2.";
    }
    container peer-flags {
      when "not(../extended-flags)" {
        description
          "Present only when the Extended Flags TLV is absent.
           When extended-flags is present it is authoritative
           and peer-flags MUST NOT be emitted.";
      }
      description
        "BMP Per-Peer Header Flags decoded from the Per-Peer Header
         Flags field.";
      reference
        "RFC 7854: BGP Monitoring Protocol (BMP), Section 4.2.";
      uses btlv:peer-header-flags;
    }
    leaf peer-distinguisher {
      type rt-types:route-distinguisher;
      mandatory true;
      description
        "BMP peer distinguisher from per-peer header.
         The routing instance on which the encapsulated PDU was
         received.";
      reference
        "RFC 7854: BGP Monitoring Protocol (BMP), Section 4.2.";
    }
    leaf peer-address {
      type inet:ip-address;
      mandatory true;
      description
        "BMP peer IP address from per-peer header.";
      reference
        "RFC 7854: BGP Monitoring Protocol (BMP), Section 4.2. The
         remote IP address associated with the TCP session over which
         the encapsulated PDU was received.";
    }
    leaf peer-as {
      type uint32;
      mandatory true;
      description
        "BMP peer autonomous system number from per-peer header. The
         Autonomous System number of the peer from which the
         encapsulated PDU was received.";
      reference
        "RFC 7854: BGP Monitoring Protocol (BMP), Section 4.2.";
    }
    leaf peer-bgp-id {
      type inet:ipv4-address;
      mandatory true;
      description
        "BMP Peer BGP ID from per-peer header. The BGP Identifier of
         the peer from which the encapsulated PDU was received.";
      reference
        "RFC 7854: BGP Monitoring Protocol (BMP), Section 4.2.";
    }
    leaf timestamp {
      type yang:date-and-time;
      description
        "BMP timestamp from the Per-Peer Header (RFC 7854 Section 4.2).
         Represents the time the encapsulated routes were received or
         installed in the Adj-RIB-In. Absent when the value was zero
         (unavailable) in the wire header.

         // TODO: check with bmp-tlv regarding authoritative timestamp
         The Timestamp TLV (message-timestamp in btlv:common) MAY
         also be present and carries a typed timestamp. When
         message-timestamp with type 'adj-rib-in-time' is present, it
         is the authoritative value for this same event; the other
         Timestamp TLV types (trigger-time, message-export-time,
         local-rib-time, adj-rib-out-time) carry additional timing
         information with no Per-Peer Header equivalent.";
      reference
        "RFC 7854: BGP Monitoring Protocol (BMP), Section 4.2.;
         draft-ietf-grow-bmp-tlv: Section 5.6.1.";
    }
  }

  typedef peer-down-reason-code {
    type enumeration {
      enum local-system-closed-notification {
        value 1;
        description
          "The local system closed the session. A BGP PDU containing
           a BGP NOTIFICATION message that would have been sent to
           the peer follows the reason code.";
        reference
          "RFC 7854: BGP Monitoring Protocol (BMP), Section 4.9.";
      }
      enum local-system-closed-fsm-event {
        value 2;
        description
          "The local system closed the session. No NOTIFICATION
           message was sent. A 2-byte field containing the FSM
           Event code follows the reason code.";
        reference
          "RFC 7854: BGP Monitoring Protocol (BMP), Section 4.9.";
      }
      enum remote-system-closed-notification {
        value 3;
        description
          "The remote system closed the session with a NOTIFICATION
           message. The BGP PDU containing the NOTIFICATION follows
           the reason code.";
        reference
          "RFC 7854: BGP Monitoring Protocol (BMP), Section 4.9.";
      }
      enum remote-system-closed-no-data {
        value 4;
        description
          "The remote system closed the session without a NOTIFICATION
           message. Includes any unexpected termination of the
           transport session.";
        reference
          "RFC 7854: BGP Monitoring Protocol (BMP), Section 4.9.";
      }
      enum peer-de-configured {
        value 5;
        description
          "Information for this peer will no longer be sent to the
           monitoring station for configuration reasons.";
        reference
          "RFC 7854: BGP Monitoring Protocol (BMP), Section 4.9.";
      }
      enum local-system-closed-tlv-data-follows {
        value 6;
        description
          "The local system closed the Loc-RIB instance peer session.
           TLV data follows (see btlv:peer-down), including the
           VRF/Table Name TLV if it was present in the Peer Up.";
        reference
          "RFC 9069: Support for Local RIB in BMP, Section 5.3.";
      }
    }
    description
      "BMP Peer Down reason codes.";
    reference
      "RFC 7854: Section 4.9; RFC 9069: Section 5.3.";
  }

  grouping mirroring {
    description
      "BMP Route Mirroring Information TLV content (type 1 in the
       Route Mirroring TLVs registry). Conveys a 2-byte information
       code about the mirrored message or message stream.";
    reference
      "RFC 7854: BGP Monitoring Protocol (BMP), Section 4.7.";
    leaf information {
      type enumeration {
        enum error-pdu {
          value 0;
          description
            "Errored PDU. The contained message was found to have
             an error causing it to be treated-as-withdraw
             (RFC 7606). A BGP Message TLV MUST also be present.";
        }
        enum message-lost {
          value 1;
          description
            "Messages Lost. One or more messages may have been
             lost, e.g., due to buffer exhaustion.";
        }
      }
      description
        "Route Mirroring Information code.";
    }
  }

  // TODO: design better grouping for statistics
  grouping statistics {
    description
      "BMP Statistics.";
    reference
      "RFC 7854: BGP Monitoring Protocol (BMP), Section 4.8.";
    leaf statistics-type {
      type string {
      }
      description
        "BMP statistics type. Defines the type of the statistic carried
         in the Stat Data field.";
    }
    leaf statistics-data {
      type uint64;
      description
        "BMP statistics data. Defines the value of the statistic.";
    }
  }

  grouping peer-up {
    description
      "BMP Peer Up Notification fields.";
    reference
      "RFC 7854: BGP Monitoring Protocol (BMP), Section 4.10.";
    leaf local-address {
      type inet:ip-address;
      description
        "Local address from the Peer Up Notification. Set to
         '0::' for Loc-RIB Instance Peers.";
      reference
        "RFC 7854: BGP Monitoring Protocol (BMP), Section 4.10.";
    }
    leaf local-port {
      type inet:port-number;
      description
        "Local port from the Peer Up Notification. Set to 0
         for Loc-RIB Instance Peers.";
      reference
        "RFC 7854: BGP Monitoring Protocol (BMP), Section 4.10.";
    }
    leaf remote-port {
      type inet:port-number;
      description
        "Remote port from the Peer Up Notification. Set to 0
         for Loc-RIB Instance Peers.";
      reference
        "RFC 7854: BGP Monitoring Protocol (BMP), Section 4.10.";
    }

    container sent-open {
      description
        "BGP OPEN message sent by the local router to its peer.";
      reference
        "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 4.2.
         RFC 7854: BGP Monitoring Protocol (BMP), Section 4.10.";
      uses bgo:bgp-open;
    }
    container received-open {
      description
        "BGP OPEN message received from the peer.";
      reference
        "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 4.2.
         RFC 7854: BGP Monitoring Protocol (BMP), Section 4.10.";
      uses bgo:bgp-open;
    }
  }

  sx:structure message {
    description
      "Augments telemetry-message-metadata with BMP specific
       subscription metadata";

    leaf version {
      type uint8;
      mandatory true;
      description
        "BMP version from common header.";
      reference
        "RFC 7854: BGP Monitoring Protocol (BMP), Section 4.1.";
    }

    container session-metadata {
      presence
        "BMP Initiation message information cached by a collector
         to enrich this message with router identity context.";
      description
        "Optional metadata derived from the BMP Initiation message
         for this BMP session. A collector MAY populate sys-name,
         sys-descr or a free-form string leaf-list to make this
         message self-contained for consumers that did not process
         or store the Initiation message directly.";
      uses btlv:information;
    }

    choice message-type {
      description
        "BMP message type from common header.";
      reference
        "RFC 7854: BGP Monitoring Protocol (BMP), Section 4.1.";
      case route-monitoring {
        container route-monitoring {
          description
            "BMP Route Monitoring message. Used for initial
             synchronization of Adj-RIBs-In and for ongoing
             incremental route monitoring.";
          uses per-peer;
          uses bre:rib-entry;
          uses btlv:route-monitoring;
          uses btlv:common;
        }
      }
      case statistics-report {
        container statistics-report {
          description
            "BMP Statistics Report message. Carries one or more
             counters reflecting activity on the monitored router.";
          uses per-peer;
          uses statistics;
          uses btlv:common;
        }
      }
      case peer-down-notification {
        container peer-down-notification {
          description
            "BMP Peer Down Notification message. Indicates that a
             peering session was terminated.";
          uses per-peer;
          leaf reason {
            type peer-down-reason-code;
            mandatory true;
            description
              "Reason why the peering session was closed.";
            reference
              "RFC 7854: BGP Monitoring Protocol (BMP), Section 4.9;
               RFC 9069: Support for Local RIB in BMP, Section 5.3.";
          }
          container peer-down {
            when "../reason = 'local-system-closed-tlv-data-follows'" {
              description
                "TLV data is present only when reason code 6 is
                 used (Loc-RIB instance peer session closed).";
            }
            description
              "Peer Down TLV data following reason code 6. Contains
               the VRF/Table Name TLV if it was present in the
               corresponding Peer Up notification.";
            uses btlv:peer-down;
          }
          uses btlv:common;
        }
      }
      case peer-up-notification {
        container peer-up-notification {
          description
            "BMP Peer Up Notification message. Indicates that a
             peering session has come up.";
          uses per-peer;
          uses peer-up;
          container information {
            presence
              "Information TLVs are present in this Peer Up
               notification";
            description
              "Optional Information TLVs at the end of the Peer Up
               message. For standard peers only the string type
               (type 0) is defined; for Loc-RIB Instance Peers the
               VRF/Table Name TLV (type 3, RFC 9069) MUST be
               included when a name is configured.";
            reference
              "RFC 7854: Section 4.10;
               RFC 9069: Section 5.2.1.";
            uses btlv:information;
          }
          uses btlv:common;
        }
      }
      case initiation-message {
        container initiation-message {
          description
            "BMP Initiation Message. Provides information about the
             monitored router. MUST be the first message sent after
             the TCP session comes up. The sysDescr and sysName
             TLVs MUST be present.";
          uses btlv:information;
          uses btlv:common;
        }
      }
      case termination-message {
        container termination-message {
          description
            "BMP Termination Message. Provides a reason why the
             monitored router is closing the BMP session.";
          uses btlv:termination;
          uses btlv:common;
        }
      }
      case route-mirroring-message {
        container route-mirroring-message {
          description
            "BMP Route Mirroring Message. Used for verbatim
             duplication of messages as received, e.g., for
             full-fidelity monitoring or error reporting.";
          uses per-peer;
          uses bre:rib-entry;
          uses mirroring;
          uses btlv:common;
        }
      }
    }
  }
}