module openconfig-routing-policy {

  yang-version "1";

  // namespace
  namespace "http://openconfig.net/yang/routing-policy";

  prefix "rpol";

  // import some basic types
  import ietf-inet-types { prefix inet; }
  import openconfig-policy-types { prefix pt; }
  import openconfig-extensions { prefix oc-ext; }

  // meta
  organization
    "OpenConfig working group";

  contact
    "OpenConfig working group
    netopenconfig@googlegroups.com";

  description
    "This module describes a YANG model for routing policy
    configuration. It is a limited subset of all of the policy
    configuration parameters available in the variety of vendor
    implementations, but supports widely used constructs for managing
    how routes are imported, exported, and modified across different
    routing protocols.  This module is intended to be used in
    conjunction with routing protocol configuration models (e.g.,
    BGP) defined in other modules.

    Route policy expression:

    Policies are expressed as a set of top-level policy definitions,
    each of which consists of a sequence of policy statements. Policy
    statements consist of simple condition-action tuples. Conditions
    may include mutiple match or comparison operations, and similarly
    actions may be multitude of changes to route attributes or a
    final disposition of accepting or rejecting the route.

    Route policy evaluation:

    Policy definitions are referenced in routing protocol
    configurations using import and export configuration statements.
    The arguments are members of an ordered list of named policy
    definitions which comprise a policy chain, and optionally, an
    explicit default policy action (i.e., reject or accept).

    Evaluation of each policy definition proceeds by evaluating its
    corresponding individual policy statements in order.  When a
    condition statement in a policy statement is satisfied, the
    corresponding action statement is executed.  If the action
    statement has either accept-route or reject-route actions, policy
    evaluation of the current policy definition stops, and no further
    policy definitions in the chain are evaluated.

    If the condition is not satisfied, then evaluation proceeds to
    the next policy statement.  If none of the policy statement
    conditions are satisfied, then evaluation of the current policy
    definition stops, and the next policy definition in the chain is
    evaluated.  When the end of the policy chain is reached, the
    default route disposition action is performed (i.e., reject-route
    unless an an alternate default action is specified for the
    chain).

    Policy 'subroutines' (or nested policies) are supported by
    allowing policy statement conditions to reference another policy
    definition which applies conditions and actions from the
    referenced policy before returning to the calling policy
    statement and resuming evaluation.  If the called policy
    results in an accept-route (either explicit or by default), then
    the subroutine returns an effective true value to the calling
    policy.  Similarly, a reject-route action returns false.  If the
    subroutine returns true, the calling policy continues to evaluate
    the remaining conditions (using a modified route if the
    subroutine performed any changes to the route).";

  oc-ext:openconfig-version "1.1.0";

  revision "2015-10-09" {
    description
      "Initial OpenConfig public release";
    reference "1.1.0";
  }

  revision "2015-05-15" {
    description
      "Initial revision";
    reference "Pre-release";
  }

  // typedef statements

  typedef default-policy-type {
    type enumeration {
      enum ACCEPT-ROUTE {
        description "default policy to accept the route";
      }
      enum REJECT-ROUTE {
        description "default policy to reject the route";
      }
    }
    description "type used to specify default route disposition in
    a policy chain";
  }


  // grouping statements

  grouping prefix-set {
    description
      "Data definition for a list of IPv4 or IPv6 prefixes which
      are matched as part of a policy";

    list prefix-set {
      key prefix-set-name;
      description
        "List of the defined prefix sets";

      leaf prefix-set-name {
        type string;
        description
          "name / label of the prefix set -- this is used to
          reference the set in match conditions";
      }

      list prefix {
        key "ip-prefix masklength-range";
        description
          "List of prefix expressions that are part of the set";

        leaf ip-prefix {
          type inet:ip-prefix;
          mandatory true;
          description
            "The prefix member in CIDR notation -- while the
            prefix may be either IPv4 or IPv6, most
            implementations require all members of the prefix set
            to be the same address family.  Mixing address types in
            the same prefix set is likely to cause an error.";
        }

        leaf masklength-range {
          type string {
            pattern '([0-9]+\.\.[0-9]+)|exact';
          }
          description
            "Defines a range for the masklength, or 'exact' if
            the prefix has an exact length.

            Example: 10.3.192.0/21 through 10.3.192.0/24 would be
            expressed as prefix: 10.3.192.0/21,
            masklength-range: 21..24.

            Example: 10.3.192.0/21 would be expressed as
            prefix: 10.3.192.0/21,
            masklength-range: exact";
        }
      }
    }
  }

  grouping neighbor-set {
    description
      "Data definition for a list of IPv4 or IPv6 neighbors which can
      be matched in a routing policy";

    list neighbor-set {
      key neighbor-set-name;
      description
          "Definitions for neighbor sets";

      leaf neighbor-set-name {
        type string;
        description
            "name / label of the neighbor set -- this is used to
            reference the set in match conditions";
      }

      list neighbor {
        key "address";
        description
            "list of addresses that are part of the neighbor set";

        leaf address {
          type inet:ip-address;
          description
              "IP address of the neighbor set member";
        }
      }
    }
  }

  grouping tag-set {
    description
      "Data definitions for a list of tags which can be matched
      in policies";

    list tag-set {
      key tag-set-name;
      description
        "Definitions for tag sets";

      leaf tag-set-name {
        type string;
        description
          "name / label of the tag set -- this is used to reference
          the set in match conditions";
      }

      list tag {
        key "value";
        description
          "list of tags that are part of the tag set";

        leaf value {
          type pt:tag-type;
          description
            "Value of the tag set member";
        }
      }
    }
  }

  grouping generic-defined-sets {
    description
      "Data definitions for pre-defined sets of attributes used in
      policy match conditions.  These sets are generic and can
      be used in matching conditions in different routing
      protocols.";

    container prefix-sets {
      description
        "Enclosing container for defined prefix sets for matching";

      uses prefix-set;
    }

    container neighbor-sets {
      description
        "Enclosing container for defined neighbor sets for matching";

      uses neighbor-set;
    }

    container tag-sets {
      description
        "Enclosing container for defined tag sets for matching";

      uses tag-set;
    }
  }

  grouping local-generic-conditions {
    description
        "Condition statement definitions for consideration of a local
        characteristic of a route";

    leaf install-protocol-eq {
      type identityref {
        base pt:install-protocol-type;
      }
      description
        "Condition to check the protocol / method used to install
        which installed the route into the local routing table";
    }
  }

  grouping match-set-options-group {
    description
      "Grouping containing options relating to how a particular set
      should be matched";

    leaf match-set-options {
      type pt:match-set-options-type;
      description
        "Optional parameter that governs the behaviour of the
        match operation";
    }
  }

  grouping match-set-options-restricted-group {
    description
      "Grouping for a restricted set of match operation modifiers";

    leaf match-set-options {
      type pt:match-set-options-restricted-type;
      description
        "Optional parameter that governs the behaviour of the
        match operation.  This leaf only supports matching on ANY
        member of the set or inverting the match.  Matching on ALL is
        not supported)";
    }
  }

  grouping generic-conditions {
    description "Condition statement definitions for checking
    membership in a generic defined set";

    container match-prefix-set {
      presence
        "The presence of this container indicates that the routes
        should match the prefix-set referenced.";

      description
        "Match a referenced prefix-set according to the logic
        defined in the match-set-options leaf";

      leaf prefix-set {
        type leafref {
          path "/routing-policy/defined-sets/prefix-sets/" +
          "prefix-set/prefix-set-name";
          //TODO: require-instance should be added when it's
          //supported in YANG 1.1
          //require-instance true;
        }
        description "References a defined prefix set";
      }
      uses match-set-options-restricted-group;
    }

    container match-neighbor-set {
      presence
        "The presence of this container indicates that the routes
        should match the neighbour set referenced";

      description
        "Match a referenced neighbor set according to the logic
        defined in the match-set-options-leaf";

      leaf neighbor-set {
        type leafref {
          path "/routing-policy/defined-sets/neighbor-sets/" +
          "neighbor-set/neighbor-set-name";
          //TODO: require-instance should be added when it's
          //supported in YANG 1.1
          //require-instance true;
        }
        description "References a defined neighbor set";
      }
      uses match-set-options-restricted-group;
    }

    container match-tag-set {
      presence
        "The presence of this container indicates that the routes
        should match the tag-set referenced";

      description
        "Match a referenced tag set according to the logic defined
        in the match-options-set leaf";

      leaf tag-set {
        type leafref {
          path "/routing-policy/defined-sets/tag-sets/tag-set" +
          "/tag-set-name";
          //TODO: require-instance should be added when it's
          //supported in YANG 1.1
          //require-instance true;
        }
        description "References a defined tag set";
      }
      uses match-set-options-restricted-group;
    }

    uses local-generic-conditions;
  }

  grouping igp-generic-conditions {
    description "grouping for IGP policy conditions";

  }


  grouping igp-conditions {
    description "grouping for IGP-specific policy conditions";

    container igp-conditions {
      description "Policy conditions for IGP attributes";

      uses igp-generic-conditions;

    }
  }

  grouping generic-actions {
    description
      "Definitions for common set of policy action statements that
      manage the disposition or control flow of the policy";

    choice route-disposition {
      description
        "Select the final disposition for the route, either
        accept or reject.";
      leaf accept-route {
        type empty;
        description "accepts the route into the routing table";
      }

      leaf reject-route {
        type empty;
        description "rejects the route";
      }
    }
  }


  grouping igp-actions {
    description "grouping for IGP-specific policy actions";

    container igp-actions {
      description "Actions to set IGP route attributes; these actions
      apply to multiple IGPs";

      leaf set-tag {
        type pt:tag-type;
        description
          "Set the tag value for OSPF or IS-IS routes.";
      }
    }
  }

  grouping routing-policy-top {
    description
      "Top level container for OpenConfig routing policy";

    container routing-policy {
      description
        "top-level container for all routing policy configuration";

      container defined-sets {
        description
            "Predefined sets of attributes used in policy match
            statements";

        uses generic-defined-sets;
        // uses bgp-defined-sets;
        // don't see a need for IGP-specific defined sets at this
        // point e.g., for OSPF, IS-IS, etc.
      }

      container policy-definitions {
        description
          "Enclosing container for the list of top-level policy
          definitions";

        list policy-definition {

          key name;
          description
            "List of top-level policy definitions, keyed by unique
            name.  These policy definitions are expected to be
            referenced (by name) in policy chains specified in import
            or export configuration statements.";


          leaf name {
            type string;
            description
                "Name of the top-level policy definition -- this name
                  is used in references to the current policy";
          }

          container statements {
            description
              "Enclosing container for policy statements";

            list statement {
              key name;
              // TODO: names of policy statements within a policy
              // definition should be optional, however, YANG
              // requires a unique id for lists; not sure that a
              // compound key works either -- need to investigate
              // further.
              ordered-by user;
              description
                "Policy statements group conditions and actions
                within a policy definition.  They are evaluated in
                the order specified (see the description of policy
                evaluation at the top of this module.";

              leaf name {
                type string;
                description "name of the policy statement";
              }

              container conditions {

                description "Condition statements for this
                  policy statement";

                leaf call-policy {
                  type leafref {
                    path "/rpol:routing-policy/" +
                      "rpol:policy-definitions/" +
                      "rpol:policy-definition/rpol:name";
                    //TODO: require-instance should be added when
                    //it is supported in YANG 1.1
                    //require-instance true;
                  }
                  description
                    "Applies the statements from the specified policy
                    definition and then returns control the current
                    policy statement. Note that the called policy may
                    itself call other policies (subject to
                    implementation limitations). This is intended to
                    provide a policy 'subroutine' capability.  The
                    called policy should contain an explicit or a
                    default route disposition that returns an
                    effective true (accept-route) or false
                    (reject-route), otherwise the behavior may be
                    ambiguous and implementation dependent";
                }
                uses generic-conditions;
                uses igp-conditions;
              }

              container actions {

                description "Action statements for this policy
                      statement";

                uses generic-actions;
                uses igp-actions;
              }
            }
          }
        }
      }
    }
  }

  grouping apply-policy-config {
    description
      "Configuration data for routing policies";

    leaf-list import-policy {
      type leafref {
        path "/rpol:routing-policy/rpol:policy-definitions/" +
          "rpol:policy-definition/rpol:name";
        //TODO: require-instance should be added when it's
        //supported in YANG 1.1
        //require-instance true;
      }
      ordered-by user;
      description
        "list of policy names in sequence to be applied on
        receiving a routing update in the current context, e.g.,
        for the current peer group, neighbor, address family,
        etc.";
    }

    leaf default-import-policy {
      type default-policy-type;
      default REJECT-ROUTE;
      description
        "explicitly set a default policy if no policy definition
        in the import policy chain is satisfied.";
    }

    leaf-list export-policy {
      type leafref {
        path "/rpol:routing-policy/rpol:policy-definitions/" +
          "rpol:policy-definition/rpol:name";
        //TODO: require-instance should be added when it's
        //supported in YANG 1.1
        //require-instance true;
      }
      ordered-by user;
      description
        "list of policy names in sequence to be applied on
        sending a routing update in the current context, e.g.,
        for the current peer group, neighbor, address family,
        etc.";
    }

    leaf default-export-policy {
      type default-policy-type;
      default REJECT-ROUTE;
      description
        "explicitly set a default policy if no policy definition
        in the export policy chain is satisfied.";
    }
  }

  grouping apply-policy-state {
    description
      "Operational state associated with routing policy";

    //TODO: identify additional state data beyond the intended
    //policy configuration.
  }

  grouping apply-policy-group {
    description
      "Top level container for routing policy applications. This
      grouping is intended to be used in routing models where
      needed.";

    container apply-policy {
      description
        "Anchor point for routing policies in the model.
        Import and export policies are with respect to the local
        routing table, i.e., export (send) and import (receive),
        depending on the context.";

      container config {
        description
          "Policy configuration data.";

        uses apply-policy-config;
      }

      container state {

        config false;
        description
          "Operational state for routing policy";

        uses apply-policy-config;
        uses apply-policy-state;
      }
    }
  }

  uses routing-policy-top;

}