module service-function-path-metadata {

    yang-version 1;

    namespace
      "urn:cisco:params:xml:ns:yang:sfc-md";

    prefix sfc-md;

    organization "Cisco Systems, Inc.";

    contact "Paul Quinn <paulq@cisco.com>";

    description
      "This module contains a collection of YANG definitions metadata
 used in a service function path between participating nodes";

    revision "2014-07-01" {
      description "Initial Version";
      reference
        "RFC XXXX: Service Path Metadata";

    }


    typedef context-metadata-ref {
      type leafref {
        path "/sfc-md:service-function-metadata/sfc-md:context-metadata/sfc-md:name";
      }
      description
        "This type is used by data models that need to reference
configured context metadata headers.";
    }

    typedef variable-metadata-ref {
      type leafref {
        path "/sfc-md:service-function-metadata/sfc-md:variable-metadata/sfc-md:name";
      }
      description
        "This type is used by data models that need to reference
configured variable metadata headers.";
    }

    container service-function-metadata {
      description
        "NSH provides a mechanism to carry shared metadata between
network  devices and service function, and between service
functions. The semantics of the shared metadata is
communicated via a control plane to participating
nodes. Examples of metadata include classification
information used for policy enforcement and network context
for forwarding post service delivery.";
      list context-metadata {
        key "name";
        description
          "Fixed Context metadata headers";
        leaf name {
          type string;
          description
            "A unique name for this set of context headers";
        }

        leaf context-header1 {
          type uint32;
          description
            "network platform context, bytes 9-12";
        }

        leaf context-header2 {
          type uint32;
          description
            "network platform context, bytes 13-16";
        }

        leaf context-header3 {
          type uint32;
          description
            "network platform context, bytes 17-20";
        }

        leaf context-header4 {
          type uint32;
          description
            "network platform context, bytes 21-24";
        }
      }  // list context-metadata

      list variable-metadata {
        key "name";
        description
          "A list that contain sets of variable length
metadata";
        leaf name {
          type string;
          description
            "A unique name for this set of variable length
metadata";
        }

        list tlv-metadata {
          key "tlv-class tlv-type";
          description
            "A set of variable length metadata";
          leaf tlv-class {
            type uint16;
            description
              "Class of TLV being used, bytes 25-26";
          }

          leaf tlv-type {
            type uint8;
            description
              "type of tlv for a given class";
          }

          leaf flags {
            type bits {
              bit r1 {
                position 24;
                description "Reserved";
              }
              bit r2 {
                position 25;
                description "Reserved";
              }
              bit r3 {
                position 26;
                description "Reserved";
              }
            }
            description "reserved flag bits";
          }

          leaf length {
            type uint8 {
              range "0..32";
            }
            description
              "Length of the variable metadata in 4-byte
words";
          }

          leaf tlv-data {
            type string;
            description "Variable Data";
          }
        }  // list tlv-metadata
      }  // list variable-metadata
    }  // container service-function-metadata
  }  // module service-function-path-metadata