I2NSF Working Group J. Kim
Internet-Draft J. Jeong
Intended status: Standards Track Sungkyunkwan University
Expires: May 8, 2019 J. Park
ETRI
S. Hares
Q. Lin
Huawei
November 4, 2018

I2NSF Network Security Function-Facing Interface YANG Data Model
draft-ietf-i2nsf-nsf-facing-interface-dm-02

Abstract

This document defines a YANG data model corresponding to the information model for Network Security Functions (NSF)-Facing Interface in Interface to Network Security Functions (I2NSF). It describes a data model for the features provided by generic security functions. This data model provides vendors with generic components that they understand well, so these generic components can be used even if they have some vendor specific functions. These generic functions represent a point of interoperability, and can be provided by any product that offers the required capabilities. Also, if they need additional features for their network security functions, the vendors can easily add the features by extending the YANG data model in this document.

Status of This Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at https://datatracker.ietf.org/drafts/current/.

Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."

This Internet-Draft will expire on May 8, 2019.

Copyright Notice

Copyright (c) 2018 IETF Trust and the persons identified as the document authors. All rights reserved.

This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.


Table of Contents

1. Introduction

This document defines a YANG [RFC6020] data model for the configuration of security services with the information model for Network Security Functions (NSF) facing interface in Interface to Network Security Functions (I2NSF). It provides a specific information model and the corresponding data models for generic network security functions (i.e., network security functions), as defined in [i2nsf-nsf-cap-im]. With these data model, I2NSF controller can control the capabilities of NSFs.

The "Event-Condition-Action" (ECA) policy model is used as the basis for the design of I2NSF Policy Rules.

The "ietf-i2nsf-nsf-facing-interface" YANG module defined in this document provides the following features:

2. Requirements Language

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119].

3. Terminology

This document uses the terminology described in [i2nsf-nsf-cap-im][RFC8431][supa-policy-info-model]. Especially, the following terms are from [supa-policy-info-model]:

3.1. Tree Diagrams

A simplified graphical representation of the data model is used in this document. The meaning of the symbols in these diagrams [RFC8431] is as follows:

4. The Structure and Objective of I2NSF Security Policy

4.1. I2NSF Security Policy Rule

This shows a policy rule for generic network security functions. The object of a policy rule is defined as policy information and rule information. This includes ECA Policy Rule such as Event Clause Objects, Condition Clause Objects, Action Clause Objects, Resolution Strategy, and Default Action.

4.2. Event Clause

This shows an event clause for generic network security functions. An Event is any important occurrence in time of a change in the system being managed, and/or in the environment of the system being managed. When used in the context of I2NSF Policy Rules, it is used to determine whether the Condition clause of the I2NSF Policy Rule can be evaluated or not. The object of an event clauses is defined as user security event, device security event, system security event, and time security event. The objects of event clauses can be extended according to specific vendor event features.

4.3. Condition Clause

This shows a condition clause for generic network security functions. A condition is defined as a set of attributes, features, and/or values that are to be compared with a set of known attributes, features, and/or values in order to determine whether or not the set of Actions in that (imperative) I2NSF Policy Rule can be executed or not. These objects are defined as packet security condition, packet payload security condition, target security condition, user security condition, context condition, and generic context condition. The objects of action clauses can be extended according to specific vendor condition features.

4.4. Action Clause

This shows an action clause for generic network security functions. An action is used to control and monitor aspects of flow-based NSFs when the event and condition clauses are satisfied. NSFs provide security functions by executing various Actions. The object of an action clause is defined as ingress action, egress action, and apply profile action. The objects of action clauses can be extended according to specific vendor action features.

5. Data Model Structure

This section shows a data model structure tree of generic network security functions that are defined in the [i2nsf-nsf-cap-im]. Note that a detailed data model for the configuration of the advanced network security functions is described in [i2nsf-advanced-nsf-dm]. The section discusses the following subjects:

5.1. I2NSF Security Policy Rule

The data model for the identification of network security policy has the following structure:

module: ietf-i2nsf-policy-rule-for-nsf
+--rw i2nsf-security-policy
   +--rw system-policy* [system-policy-name]
      +--rw system-policy-name     string
      +--rw priority-usage         priority-usage-type
      +--rw rules* [rule-name]
      |  +--rw rule-name                     string
      |  +--rw rule-description?             string
      |  +--rw rule-priority?                uint8
      |  +--rw enable?                       boolean
      |  +--rw session-aging-time?           uint16
      |  +--rw long-connection
      |  |  +--rw enable?   boolean
      |  |  +--rw during?   uint16
      |  +--rw time-zone
      |  |  +--rw absolute-time-zone
      |  |  |  +--rw time
      |  |  |  |  +--rw start-time?   yang:date-and-time
      |  |  |  |  +--rw end-time?     yang:date-and-time
      |  |  |  +--rw date
      |  |  |     +--rw absolute-date?   yang:date-and-time
      |  |  +--rw periodic-time-zone
      |  |     +--rw day
      |  |     |  +--rw sunday?      boolean
      |  |     |  +--rw monday?      boolean
      |  |     |  +--rw tuesday?     boolean
      |  |     |  +--rw wednesday?   boolean
      |  |     |  +--rw thursday?    boolean
      |  |     |  +--rw friday?      boolean
      |  |     |  +--rw saturday?    boolean
      |  |     +--rw month
      |  |        +--rw january?     boolean
      |  |        +--rw february?    boolean
      |  |        +--rw march?       boolean
      |  |        +--rw april?       boolean
      |  |        +--rw may?         boolean
      |  |        +--rw june?        boolean
      |  |        +--rw july?        boolean
      |  |        +--rw august?      boolean
      |  |        +--rw september?   boolean
      |  |        +--rw october?     boolean
      |  |        +--rw november?    boolean
      |  |        +--rw december?    boolean
      |  +--rw event-clause-container
      |  |  ...
      |  +--rw condition-clause-container
      |  |  ...
      |  +--rw action-clause-container
      |     ...
      +--rw resolution-strategy
      |  +--rw (resolution-strategy-type)?
      |     +--:(fmr)
      |     |  +--rw first-matching-rule?   boolean
      |     +--:(lmr)
      |        +--rw last-matching-rule?    boolean
      +--rw default-action
      |  +--rw default-action-type?   boolean
      +--rw rule-group
         +--rw groups* [group-name]
            +--rw group-name     string
            +--rw rule-range
            |  +--rw start-rule?   string
            |  +--rw end-rule?     string
            +--rw enable?        boolean
            +--rw description?   string

    

Figure 1: Data Model Structure for Network Security Policy Identification

5.2. Event Clause

The data model for event rule has the following structure:

module: ietf-i2nsf-policy-rule-for-nsf
+--rw i2nsf-security-policy
   +--rw system-policy* [system-policy-name]
      ...
      |  +--rw event-clause-container
      |  |  +--rw event-clause-list* [eca-object-id]
      |  |     +--rw entity-class?        identityref
      |  |     +--rw eca-object-id        string
      |  |     +--rw description?         string
      |  |     +--rw sec-event-content    string
      |  |     +--rw sec-event-format     sec-event-format
      |  |     +--rw sec-event-type       string
      |  +--rw condition-clause-container
      |  |  ...
      |  +--rw action-clause-container
      |     ...
      +--rw resolution-strategy
      |  ...
      +--rw default-action
      |  ...
      +--rw rule-group
         ...

Figure 2: Data Model Structure for Event Rule

These objects are defined as user security event, device security event, system security event, and time security event. These objects can be extended according to specific vendor event features. We will add additional event objects for more generic network security functions.

5.3. Condition Clause

The data model for condition rule has the following structure:

module: ietf-i2nsf-policy-rule-for-nsf
+--rw i2nsf-security-policy
   +--rw system-policy* [system-policy-name]
      ...
      |  +--rw event-clause-container
      |  |  ...
      |  +--rw condition-clause-container
      |  |  +--rw condition-clause-list* [eca-object-id]
      |  |     +--rw entity-class?                identityref
      |  |     +--rw eca-object-id                string
      |  |     +--rw packet-security-condition
      |  |     |  +--rw packet-description?               string
      |  |     |  +--rw packet-security-mac-condition
      |  |     |  |  +--rw pkt-sec-cond-mac-dest*    yang:phys-address
      |  |     |  |  +--rw pkt-sec-cond-mac-src*     yang:phys-address
      |  |     |  |  +--rw pkt-sec-cond-mac-8021q*        string
      |  |     |  |  +--rw pkt-sec-cond-mac-ether-type*   string
      |  |     |  |  +--rw pkt-sec-cond-mac-tci*          string
      |  |     |  +--rw packet-security-ipv4-condition
      |  |     |  |  +--rw pkt-sec-cond-ipv4-header-length*     uint8
      |  |     |  |  +--rw pkt-sec-cond-ipv4-tos*               uint8
      |  |     |  |  +--rw pkt-sec-cond-ipv4-total-length*      uint16
      |  |     |  |  +--rw pkt-sec-cond-ipv4-id*                uint8
      |  |     |  |  +--rw pkt-sec-cond-ipv4-fragment*          uint8
      |  |     |  |  +--rw pkt-sec-cond-ipv4-fragment-offset*   uint16
      |  |     |  |  +--rw pkt-sec-cond-ipv4-ttl*               uint8
      |  |     |  |  +--rw pkt-sec-cond-ipv4-protocol*          uint8
      |  |     |  |  +--rw pkt-sec-cond-ipv4-src*      inet:ipv4-address
      |  |     |  |  +--rw pkt-sec-cond-ipv4-dest*     inet:ipv4-address
      |  |     |  |  +--rw pkt-sec-cond-ipv4-ipopts?            string
      |  |     |  |  +--rw pkt-sec-cond-ipv4-sameip?            boolean
      |  |     |  |  +--rw pkt-sec-cond-ipv4-geoip*             string
      |  |     |  +--rw packet-security-ipv6-condition
      |  |     |  |  +--rw pkt-sec-cond-ipv6-dscp*             string
      |  |     |  |  +--rw pkt-sec-cond-ipv6-ecn*              string
      |  |     |  |  +--rw pkt-sec-cond-ipv6-traffic-class*    uint8
      |  |     |  |  +--rw pkt-sec-cond-ipv6-flow-label*       uint32
      |  |     |  |  +--rw pkt-sec-cond-ipv6-payload-length*   uint16
      |  |     |  |  +--rw pkt-sec-cond-ipv6-next-header*      uint8
      |  |     |  |  +--rw pkt-sec-cond-ipv6-hop-limit*        uint8
      |  |     |  |  +--rw pkt-sec-cond-ipv6-src*      inet:ipv6-address
      |  |     |  |  +--rw pkt-sec-cond-ipv6-dest*     inet:ipv6-address
      |  |     |  +--rw packet-security-tcp-condition
      |  |     |  |  +--rw pkt-sec-cond-tcp-src-port*   inet:port-number
      |  |     |  |  +--rw pkt-sec-cond-tcp-dest-port*  inet:port-number
      |  |     |  |  +--rw pkt-sec-cond-tcp-seq-num*       uint32
      |  |     |  |  +--rw pkt-sec-cond-tcp-ack-num*       uint32
      |  |     |  |  +--rw pkt-sec-cond-tcp-window-size*   uint16
      |  |     |  |  +--rw pkt-sec-cond-tcp-flags*         uint8
      |  |     |  +--rw packet-security-udp-condition
      |  |     |  |  +--rw pkt-sec-cond-udp-src-port*   inet:port-number
      |  |     |  |  +--rw pkt-sec-cond-udp-dest-port*  inet:port-number
      |  |     |  |  +--rw pkt-sec-cond-udp-length*      string
      |  |     |  +--rw packet-security-icmp-condition
      |  |     |     +--rw pkt-sec-cond-icmp-type*      uint8
      |  |     |     +--rw pkt-sec-cond-icmp-code*      uint8
      |  |     |     +--rw pkt-sec-cond-icmp-seg-num*   uint32
      |  |     +--rw packet-payload-condition
      |  |     |  +--rw packet-payload-description?   string
      |  |     |  +--rw pkt-payload-content*          string
      |  |     +--rw acl-number?                  uint32
      |  |     +--rw application-condition
      |  |     |  +--rw application-description?   string
      |  |     |  +--rw application-object*        string
      |  |     |  +--rw application-group*         string
      |  |     |  +--rw application-label*         string
      |  |     |  +--rw category
      |  |     |     +--rw application-category* 
      |  |     |                  [name application-subcategory]
      |  |     |        +--rw name                       string
      |  |     |        +--rw application-subcategory    string
      |  |     +--rw target-condition
      |  |     |  +--rw target-description?        string
      |  |     |  +--rw device-sec-context-cond
      |  |     |     +--rw pc?                 boolean
      |  |     |     +--rw mobile-phone?       boolean
      |  |     |     +--rw voip-volte-phone?   boolean
      |  |     |     +--rw tablet?             boolean
      |  |     |     +--rw iot?                boolean
      |  |     |     +--rw vehicle?            boolean
      |  |     +--rw users-condition
      |  |     |  +--rw users-description?   string
      |  |     |  +--rw user
      |  |     |  |  +--rw (user-name)?
      |  |     |  |     +--:(tenant)
      |  |     |  |     |  +--rw tenant    uint8
      |  |     |  |     +--:(vn-id)
      |  |     |  |        +--rw vn-id     uint8
      |  |     |  +--rw group
      |  |     |  |  +--rw (group-name)?
      |  |     |  |     +--:(tenant)
      |  |     |  |     |  +--rw tenant    uint8
      |  |     |  |     +--:(vn-id)
      |  |     |  |        +--rw vn-id     uint8
      |  |     |  +--rw security-grup        string
      |  |     +--rw url-category-condition
      |  |     |  +--rw url-category-description?   string
      |  |     |  +--rw pre-defined-category*       string
      |  |     |  +--rw user-defined-category*      string
      |  |     +--rw context-condition
      |  |     |  +--rw context-description?   string
      |  |     +--rw gen-context-condition
      |  |        +--rw gen-context-description?   string
      |  |        +--rw geographic-location
      |  |           +--rw src-geographic-location*    uint32
      |  |           +--rw dest-geographic-location*   uint32
      |  +--rw action-clause-container
      |     ...
      +--rw resolution-strategy
      |  ...
      +--rw default-action
      |  ...
      +--rw rule-group
         ...

Figure 3: Data Model Structure for Condition Rule

These objects are defined as packet security condition, packet payload security condition, target security condition, user security condition, context condition, and generic context condition. These objects can be extended according to specific vendor condition features. We will add additional condition objects for more generic network security functions.

5.4. Action Clause

The data model for action rule has the following structure:

module: ietf-i2nsf-policy-rule-for-nsf
+--rw i2nsf-security-policy
   +--rw system-policy* [system-policy-name]
      ...
      |  +--rw event-clause-container
      |  |  ...
      |  +--rw condition-clause-container
      |  |  ...
      |  +--rw action-clause-container
      |     +--rw action-clause-list* [eca-object-id]
      |        +--rw entity-class?     identityref
      |        +--rw eca-object-id     string
      |        +--rw rule-log?         boolean
      |        +--rw session-log?      boolean
      |        +--rw ingress-action
      |        |  +--rw ingress-description?   string
      |        |  +--rw ingress-action-type?   ingress-action
      |        +--rw egress-action
      |        |  +--rw egress-description?   string
      |        |  +--rw egress-action-type?   egress-action
      |        +--rw apply-profile
      |           +--rw profile-description?         string
      |           +--rw content-security-control
      |           |  +--rw content-security-control-types
      |           |     +--rw antivirus?             string
      |           |     +--rw ips?                   string
      |           |     +--rw ids?                   string
      |           |     +--rw url-filtering?         string
      |           |     +--rw data-filtering?        string
      |           |     +--rw mail-filtering?        string
      |           |     +--rw file-blocking?         string
      |           |     +--rw file-isolate?          string
      |           |     +--rw pkt-capture?           string
      |           |     +--rw application-control?   string
      |           |     +--rw voip-volte?            string
      |           +--rw attack-mitigation-control
      |              +--rw ddos-attack
      |              |  +--rw ddos-attack-type
      |              |     +--rw network-layer-ddos-attack
      |              |     |  +--rw network-layer-ddos-attack-type
      |              |     |     +--rw syn-flood?       string
      |              |     |     +--rw udp-flood?       string
      |              |     |     +--rw icmp-flood?      string
      |              |     |     +--rw ip-frag-flood?   string
      |              |     |     +--rw ipv6-related?    string
      |              |     +--rw app-layer-ddos-attack
      |              |        +--rw app-ddos-attack-types
      |              |           +--rw http-flood?      string
      |              |           +--rw https-flood?     string
      |              |           +--rw dns-flood?       string
      |              |           +--rw dns-amp-flood?   string
      |              |           +--rw ssl-ddos?        string
      |              +--rw single-packet-attack
      |                 +--rw single-packet-attack-type
      |                    +--rw scan-and-sniff-attack
      |                    |  +--rw scan-and-sniff-attack-types
      |                    |     +--rw ip-sweep?        string
      |                    |     +--rw port-scanning?   string
      |                    +--rw malformed-packet-attack
      |                    |  +--rw malformed-packet-attack-types
      |                    |     +--rw ping-of-death?   string
      |                    |     +--rw teardrop?        string
      |                    +--rw special-packet-attack
      |                       +--rw special-packet-attack-types
      |                          +--rw oversized-icmp?   string
      |                          +--rw tracert?          string
      +--rw resolution-strategy
      |  ...
      +--rw default-action
      |  ...
      +--rw rule-group
         ...

Figure 4: Data Model Structure for Action Rule

These objects are defined as ingress action, egress action, and apply profile action. These objects can be extended according to specific vendor action feature. We will add additional action objects for more generic network security functions.

6. YANG Module

6.1. IETF NSF-Facing Interface YANG Data Module

This section introduces a YANG module for the information model of network security functions, as defined in the [i2nsf-nsf-cap-im].

<CODE BEGINS> file "ietf-i2nsf-policy-rule-for-nsf@2018-11-04.yang"

module ietf-i2nsf-policy-rule-for-nsf {
  yang-version 1.1;
  namespace 
    "urn:ietf:params:xml:ns:yang:ietf-i2nsf-policy-rule-for-nsf";
  prefix
    policy-rule-for-nsf;

  import ietf-inet-types{
    prefix inet;
  }
  import ietf-yang-types{
    prefix yang;
  }

  organization
    "IETF I2NSF (Interface to Network Security Functions) 
     Working Group";

  contact
    "WG Web: <http://tools.ietf.org/wg/i2nsf>
     WG List: <mailto:i2nsf@ietf.org>

     WG Chair: Adrian Farrel
     <mailto:Adrain@olddog.co.uk>

     WG Chair: Linda Dunbar
     <mailto:Linda.duhbar@huawei.com>

     Editor: Jingyong Tim Kim 
     <mailto:timkim@skku.edu>
    
     Editor: Jaehoon Paul Jeong
     <mailto:pauljeong@skku.edu>
     
     Editor: Susan Hares
     <mailto:shares@ndzh.com>";

  description
    "This module defines a YANG data module for network security 
     functions.";
  revision "2018-11-04"{
    description "The fourth revision";
    reference
      "draft-ietf-i2nsf-capability-04";
  }
  
  typedef sec-event-format {
      type enumeration {
        enum unknown {
            description
              "If SecEventFormat is unknown";
        }
        enum guid {
            description
              "If SecEventFormat is GUID 
              (Generic Unique IDentifier)";
        }
        enum uuid {
            description
              "If SecEventFormat is UUID 
              (Universal Unique IDentifier)";
        }
        enum uri {
            description
              "If SecEventFormat is URI 
              (Uniform Resource Identifier)";
        }
        enum fqdn {
            description
              "If SecEventFormat is FQDN 
              (Fully Qualified Domain Name)";
        }
        enum fqpn {
            description
              "If SecEventFormat is FQPN 
              (Fully Qualified Path Name)";
        }
      }
      description
        "This is used for SecEventFormat.";
  }
  
  typedef priority-usage-type {
      type enumeration {
        enum priority-by-order {
            description
              "If priority type is order";
        }
        enum priority-by-number {
            description
              "If priority type is number";
        }
      }
      description
        "This is used for priority type.";
  } 

  typedef ingress-action {
      type enumeration {
        enum pass {
            description
              "If ingress action is pass";
        }
        enum drop {
            description
              "If ingress action is drop";
        }
        enum reject {
            description
              "If ingress action is reject";
        }
        enum alert {
            description
              "If ingress action is alert";
        }
        enum mirror {
            description
              "If ingress action is mirror";
        }
      }
      description
        "This is used for ingress action.";
  }

  typedef egress-action {
      type enumeration {
        enum invoke-signaling {
            description
              "If egress action is invoke signaling";
        }
        enum tunnel-encapsulation {
            description
              "If egress action is tunnel encapsulation";
        }
        enum forwarding {
            description
              "If egress action is forwarding";
        }
        enum redirection {
            description
              "If egress action is redirection";
        }
      }
      description
        "This is used for egress action.";
  } 

  identity ECA-OBJECT-TYPE {
    description "TBD";
  }
  
  identity ECA-EVENT-TYPE {
    base ECA-OBJECT-TYPE;
    description "TBD";
  }
  
  identity ECA-CONDITION-TYPE {
    base ECA-OBJECT-TYPE;
    description "TBD";
  }
  
  identity ECA-ACTION-TYPE {
    base ECA-OBJECT-TYPE;
    description "TBD";
  }  
  
   identity EVENT-USER-TYPE {
    base ECA-EVENT-TYPE;
    description "TBD";
  } 
  
   identity EVENT-DEV-TYPE {
    base ECA-EVENT-TYPE;
    description "TBD";
  } 
  
   identity EVENT-SYS-TYPE {
    base ECA-EVENT-TYPE;
    description "TBD";
  } 
  
   identity EVENT-TIME-TYPE {
    base ECA-EVENT-TYPE;
    description "TBD";
  } 
  
  
  grouping i2nsf-eca-object-type {
    leaf entity-class {
      type identityref {
        base ECA-OBJECT-TYPE;
      }
      description "TBD";
    }
    leaf eca-object-id {
        type string;
        description "TBD";
    }
    description "TBD";
  }

  grouping i2nsf-event-type {
      description "TBD";
      leaf description {
        type string;
        description
          "This is description for event.
          Vendors can write instructions for event 
          that vendor made";
      }
      
      leaf sec-event-content {
        type string;
        mandatory true;
        description
         "This is a mandatory string that contains the content 
          of the SecurityEvent. The format of the content 
          is specified in the SecEventFormat class 
          attribute, and the type of event is defined in the 
          SecEventType class attribute. An example of the 
          SecEventContent attribute is a string hrAdmin,
          with the SecEventFormat set to 1 (GUID) and the 
          SecEventType attribute set to 5 (new logon).";
      }
      
      leaf sec-event-format {
        type sec-event-format;
        mandatory true;
        description
         "This is a mandatory uint 8 enumerated integer, which 
          is used to specify the data type of the 
          SecEventContent attribute. The content is 
          specified in the SecEventContent class attribute, 
          and the type of event is defined in the 
          SecEventType class attribute. An example of the 
          SecEventContent attribute is string hrAdmin, 
          with the SecEventFormat attribute set to 1 (GUID) 
          and the SecEventType attribute set to 5 
          (new logon).";
      }
      
      leaf sec-event-type {
        type string;
        mandatory true;
        description
         "This is a mandatory uint 8 enumerated integer, which 
          is used to specify the type of event that involves 
          this user. The content and format are specified in 
          the SecEventContent and SecEventFormat class 
          attributes, respectively. An example of the 
          SecEventContent attribute is string hrAdmin, 
          with the SecEventFormat attribute set to 1 (GUID) 
          and the SecEventType attribute set to 5 
         (new logon).";
      }
    
 }  
 

  container i2nsf-security-policy {
    description
      "policy is a container
       including a set of security rules according to certain logic, 
       i.e., their similarity or mutual relations, etc. The network
       security policy is able to apply over both the unidirectional
       and bidirectional traffic across the NSF.";
       
      list system-policy {
        key "system-policy-name";
        description
          "The system-policy represents there could be multiple system 
          policies in one NSF, and each system policy is used by 
          one virtual instance of the NSF/device.";
       
      
      leaf system-policy-name {
        type string;
        mandatory true;     
        description
          "The name of the policy. 
           This must be unique.";
      }  
     
     
       leaf priority-usage {
        type priority-usage-type;
        mandatory true; 
        description
          "This is priority type.";
      }
      
      list rules {
        key "rule-name";
        description
          "This is a rule for network security functions.";
            
        leaf rule-name {
          type string;
          mandatory true;
          description
            "The id of the rule.
             This must be unique.";
        }
        
        leaf rule-description {
          type string;
          description
            "This description gives more information about 
             rules.";
        }
    
        leaf rule-priority {
          type uint8;
          description
            "The priority keyword comes with a mandatory 
             numeric value which can range from 1 till 255.";
        }
        
        leaf enable {
          type boolean;
          description
            "True is enable.
             False is not enbale.";
        }

        leaf session-aging-time {
          type uint16;
          description
            "This is session aging time.";
        }

        container long-connection {
          description
            "This is long-connection";
             
          leaf enable {
            type boolean;
            description
              "True is enable.
               False is not enbale.";
          }
        
          leaf during {
            type uint16;
            description
              "This is during time.";
          }
        }       
        
        container time-zone {
          description
            "This can be used to apply rules according to time-zone";
          container absolute-time-zone {
            description
            "This can be used to apply rules according to 
             absolute-time";          
            container time {
              description
                "This can be used to apply rules according to time";
              leaf start-time {
                type yang:date-and-time;
                description
                  "This is start time for time zone";
              }
              leaf end-time {
                type yang:date-and-time;
                description
                  "This is end time for time zone";
              }
            }
            container date {
              description
                "This can be used to apply rules according to date";
              leaf absolute-date {
                type yang:date-and-time;
                description
                  "This is absolute date for time zone";
              }
            }
          }
          container periodic-time-zone {
            description
             "This can be used to apply rules according to 
             periodic-time-zone";          
            container day {
              description
               "This can be used to apply rules according 
                to periodic day";
              leaf sunday {
                type boolean;
                description
                  "This is sunday for periodic day";
              }
              leaf monday {
                type boolean;
                description
                  "This is monday for periodic day";
              }
              leaf tuesday {
                type boolean;
                description
                  "This is tuesday for periodic day";
              }
              leaf wednesday {
                type boolean;
                description
                  "This is wednesday for periodic day";
              }
              leaf thursday {
                type boolean;
                description
                  "This is thursday for periodic day";
              }
              leaf friday {
                type boolean;
                description
                  "This is friday for periodic day";
              }
              leaf saturday {
                type boolean;
                description
                  "This is saturday for periodic day";
              }
            }
            container month {
              description
               "This can be used to apply rules according 
                to periodic month";
              leaf january {
                type boolean;
                description
                  "This is january for periodic month";
              }
              leaf february {
                type boolean;
                description
                  "This is february for periodic month";
              }
              leaf march {
                type boolean;
                description
                  "This is march for periodic month";
              }
              leaf april {
                type boolean;
                description
                  "This is april for periodic month";
              }
              leaf may {
                type boolean;
                description
                  "This is may for periodic month";
              }
              leaf june {
                type boolean;
                description
                  "This is june for periodic month";
              }
              leaf july {
                type boolean;
                description
                  "This is july for periodic month";
              }
              leaf august {
                type boolean;
                description
                  "This is august for periodic month";
              }
              leaf september {
                type boolean;
                description
                  "This is september for periodic month";
              }
              leaf october {
                type boolean;
                description
                  "This is october for periodic month";
              }
              leaf november {
                type boolean;
                description
                  "This is november for periodic month";
              }
              leaf december {
                type boolean;
                description
                  "This is december for periodic month";
              }
            }
          }
        }    

    container event-clause-container {
      description "TBD";
      list event-clause-list {
      key eca-object-id;
      uses i2nsf-eca-object-type {
        refine entity-class {
            default ECA-EVENT-TYPE;
        }
      }
      
      description 
        " This is abstract. An event is defined as any important 
          occurrence in time of a change in the system being 
          managed, and/or in the environment of the system being 
          managed. When used in the context of policy rules for 
          a flow-based NSF, it is used to determine whether the 
          Condition clause of the Policy Rule can be evaluated 
          or not. Examples of an I2NSF event include time and 
          user actions (e.g., logon, logoff, and actions that 
          violate any ACL.).";
              
       uses i2nsf-event-type;
       }
    }
      container condition-clause-container {
      description "TBD";
      list condition-clause-list {
        key eca-object-id;
        uses i2nsf-eca-object-type {
            refine entity-class {
                default ECA-CONDITION-TYPE;
            }
        }
        description 
          " This is abstract.  A condition is defined as a set 
          of attributes, features, and/or values that are to be 
          compared with a set of known attributes, features, 
          and/or values in order to determine whether or not the 
          set of Actions in that (imperative) I2NSF Policy Rule 
          can be executed or not. Examples of I2NSF Conditions
          include matching attributes of a packet or flow, and 
          comparing the internal state of an NSF to a desired 
          state.";
            
          container packet-security-condition {
            description
              "TBD";          
            leaf packet-description {
              type string;
              description
                "This is description for packet condition.
                Vendors can write instructions for packet condition 
                that vendor made";
            }
  
            container packet-security-mac-condition {
              description
               "The purpose of this Class is to represent packet MAC
               packet header information that can be used as part of
               a test to determine if the set of Policy Actions in
               this ECA Policy Rule should be execute or not.";
  
              leaf-list pkt-sec-cond-mac-dest {
                type yang:phys-address;
                description
                  "The MAC destination address (6 octets long).";
              }
  
              leaf-list pkt-sec-cond-mac-src {
                type yang:phys-address;
                description
                  "The MAC source address (6 octets long).";
              }
  
              leaf-list pkt-sec-cond-mac-8021q {
                type string;
                description
                  "This is an optional string attribute, and defines
                   The 802.1Q tab value (2 octets long).";
              }
  
              leaf-list pkt-sec-cond-mac-ether-type {
                type string;
                description
                  "The EtherType field (2 octets long). Values up to
                   and including 1500 indicate the size of the 
                   payload in octets; values of 1536 and above
                   define which protocol is encapsulated in the 
                   payload of the frame.";
              }
  
              leaf-list pkt-sec-cond-mac-tci {
                type string;
                description
                 "This is an optional string attribute, and defines
                  the Tag Control Information. This consists of a 3
                  bit user priority field, a drop eligible indicator
                  (1 bit), and a VLAN identifier (12 bits).";
              }
            }
  
            container packet-security-ipv4-condition {
              description
                "The purpose of this Class is to represent IPv4
                 packet header information that can be used as 
                 part of a test to determine if the set of Policy
                 Actions in this ECA Policy Rule should be executed 
                 or not.";
  
              leaf-list pkt-sec-cond-ipv4-header-length {
                type uint8;
                description
                  "The IPv4 packet header consists of 14 fields, 
                   of which 13 are required.";
              }
  
              leaf-list pkt-sec-cond-ipv4-tos {
                type uint8;
                description
                  "The ToS field could specify a datagram's priority
                   and request a route for low-delay, 
                   high-throughput, or highly-reliable service..";
              }
  
              leaf-list pkt-sec-cond-ipv4-total-length {
                type uint16;
                description
                  "This 16-bit field defines the entire packet size,
                   including header and data, in bytes.";
              }
  
              leaf-list pkt-sec-cond-ipv4-id {
                type uint8;
                description
                  "This field is an identification field and is 
                   primarily used for uniquely identifying 
                   the group of fragments of a single IP datagram.";
              }
  
              leaf-list pkt-sec-cond-ipv4-fragment {
                type uint8;
                description
                  "IP fragmentation is an Internet Protocol (IP)
                   process that breaks datagrams into smaller pieces 
                   (fragments), so that packets may be formed that 
                   can pass through a link with a smaller maximum 
                   transmission unit (MTU) than the original 
                   datagram size.";
              }
  
              leaf-list pkt-sec-cond-ipv4-fragment-offset {
                type uint16;
                description
                  "Fragment offset field along with Don't Fragment 
                   and More Fragment flags in the IP protocol 
                   header are used for fragmentation and reassembly 
                   of IP datagrams.";
              } 
  
              leaf-list pkt-sec-cond-ipv4-ttl {
                type uint8;
                description
                  "The ttl keyword is used to check for a specific
                   IP time-to-live value in the header of 
                   a packet."; 
              }
  
              leaf-list pkt-sec-cond-ipv4-protocol {
                type uint8;
                description
                  "Internet Protocol version 4(IPv4) is the fourth
                   version of the Internet Protocol (IP).";
              }
  
              leaf-list pkt-sec-cond-ipv4-src {
                type inet:ipv4-address;
                description
                  "Defines the IPv4 Source Address.";
              }
  
              leaf-list pkt-sec-cond-ipv4-dest {
                type inet:ipv4-address;
                description
                  "Defines the IPv4 Destination Address.";
              }
  
              leaf pkt-sec-cond-ipv4-ipopts {
                type string;
                description
                  "With the ipopts keyword you can check if 
                   a specific ip option is set. Ipopts has 
                   to be used at the beginning of a rule."; 
              }
  
              leaf pkt-sec-cond-ipv4-sameip {
                type boolean;
                description
                  "Every packet has a source IP-address and 
                   a destination IP-address. It can be that 
                   the source IP is the same as 
                   the destination IP.";
              }
  
              leaf-list pkt-sec-cond-ipv4-geoip {
                type string;
                description
                  "The geoip keyword enables you to match on 
                   the source, destination or source and destination
                   IP addresses of network traffic and to see to
                   which country it belongs. To do this, Suricata 
                   uses GeoIP API with MaxMind database format.";
              }
            }
              
            container packet-security-ipv6-condition {
              description
                 "The purpose of this Class is to represent packet 
                 IPv6 packet header information that can be used as 
                 part of a test to determine if the set of Policy 
                 Actions in this ECA Policy Rule should be executed 
                 or not.";
                  
              leaf-list pkt-sec-cond-ipv6-dscp {
                type string;
                description
                  "Differentiated Services Code Point (DSCP) 
                   of ipv6.";
              }
  
              leaf-list pkt-sec-cond-ipv6-ecn {
                type string;
                description
                  "ECN allows end-to-end notification of network 
                   congestion without dropping packets.";
              }
  
              leaf-list pkt-sec-cond-ipv6-traffic-class {
                type uint8;
                description
                  "The bits of this field hold two values. The 6
                   most-significant bits are used for 
                   differentiated services, which is used to
                   classify packets.";
              }
  
              leaf-list pkt-sec-cond-ipv6-flow-label {
                type uint32;
                description
                  "The flow label when set to a non-zero value 
                   serves as a hint to routers and switches 
                   with multiple outbound paths that these 
                   packets should stay on the same path so that
                   they will not be reordered."; 
              }
  
              leaf-list pkt-sec-cond-ipv6-payload-length {
                type uint16;
                description
                  "The size of the payload in octets, 
                   including any extension headers.";
              }
  
              leaf-list pkt-sec-cond-ipv6-next-header {
                type uint8;
                description
                  "Specifies the type of the next header. 
                   This field usually specifies the transport 
                   layer protocol used by a packet's payload.";
              }
  
              leaf-list pkt-sec-cond-ipv6-hop-limit {
                type uint8;
                description
                  "Replaces the time to live field of IPv4.";
              }
  
              leaf-list pkt-sec-cond-ipv6-src {
                type inet:ipv6-address;
                description
                  "The IPv6 address of the sending node.";
              }
  
              leaf-list pkt-sec-cond-ipv6-dest {
                type inet:ipv6-address;
                description
                  "The IPv6 address of the destination node(s).";
              }
            }
              
            container packet-security-tcp-condition {
              description
                "The purpose of this Class is to represent packet 
                 TCP packet header information that can be used as 
                 part of a test to determine if the set of Policy 
                 Actions in this ECA Policy Rule should be executed 
                 or not.";
 
              leaf-list pkt-sec-cond-tcp-src-port {
                type inet:port-number;
                description
                  "This is a mandatory string attribute, and 
                  defines the Source Port number (16 bits).";
              }
 
              leaf-list pkt-sec-cond-tcp-dest-port {
                type inet:port-number;
                description
                  "This is a mandatory string attribute, and 
                  defines the Destination Port number (16 bits).";
              }
              
              leaf-list pkt-sec-cond-tcp-seq-num {
                type uint32;
                description
                  "If the SYN flag is set (1), then this is the
                   initial sequence number.";
              }
  
              leaf-list pkt-sec-cond-tcp-ack-num {
                type uint32;
                description
                  "If the ACK flag is set then the value of this 
                   field is the next sequence number that the sender
                   is expecting.";
              }
  
              leaf-list pkt-sec-cond-tcp-window-size {
                type uint16;
                description
                  "The size of the receive window, which specifies 
                   the number of windows size units 
                   (by default,bytes) (beyond the segment 
                   identified by the sequence number in the
                   acknowledgment field) that the sender of this
                   segment is currently willing to recive.";
              }
  
              leaf-list pkt-sec-cond-tcp-flags {
                type uint8;
                description
                  "This is a mandatory string attribute, and defines 
                   the nine Control bit flags (9 bits).";
              }
            }
              
            container packet-security-udp-condition {
              description
               "The purpose of this Class is to represent packet UDP
                packet header information that can be used as part 
                of a test to determine if the set of Policy Actions 
                in this ECA Policy Rule should be executed or not.";
                  
              leaf-list pkt-sec-cond-udp-src-port {
                type inet:port-number;
                description
                  "This is a mandatory string attribute, and 
                  defines the UDP Source Port number (16 bits).";
              }
 
              leaf-list pkt-sec-cond-udp-dest-port {
                type inet:port-number;
                description
                  "This is a mandatory string attribute, and 
                  defines the UDP Destination Port number (16 bits).";
              }
                  
              leaf-list pkt-sec-cond-udp-length {
                type string;
                description
                 "This is a mandatory string attribute, and defines 
                  the length in bytes of the UDP header and data 
                  (16 bits).";
              }
            }
  
            container packet-security-icmp-condition {
              description
                "The internet control message protocol condition.";
  
              leaf-list pkt-sec-cond-icmp-type {
                type uint8;
                description
                  "ICMP type, see Control messages.";
              }
  
              leaf-list pkt-sec-cond-icmp-code {
                type uint8;
                description
                  "ICMP subtype, see Control messages.";
              }
  
              leaf-list pkt-sec-cond-icmp-seg-num {
                type uint32;
                description
                  "The icmp Sequence Number.";
              }
            }
          }
          
          container packet-payload-condition {
            description
              "TBD";          
            leaf packet-payload-description {
              type string;
              description
               "This is description for payload condition.
               Vendors can write instructions for payload condition 
               that vendor made";
            }
            leaf-list pkt-payload-content {
              type string;
              description
                "The content keyword is very important in 
                 signatures. Between the quotation marks you
                 can write on what you would like the
                 signature to match.";
            }
          }  
          
          leaf acl-number {
            type uint32;
            description
             "This is acl-number.";
          }
          
          container application-condition {
            description
              "TBD";          
            leaf application-description {
              type string;
              description
               "This is description for application condition.";
            }
            leaf-list application-object {
              type string;
              description
                "This is application object.";
            }
            leaf-list application-group {
              type string;
              description
                "This is application group.";
            }
            leaf-list application-label {
              type string;
              description
                "This is application label.";
            }
            container category {
              description
                "TBD"; 
              list application-category {
                key "name application-subcategory";
                description
                  "TBD";
                leaf name {
                  type string;
                  description
                   "This is name for application category.";
                }
                leaf application-subcategory {
                  type string;
                  description
                   "This is application subcategory.";
                }
              }               
            }               
          }  
          
          container target-condition {
            description
              "TBD";
            leaf target-description {
              type string;
              description
                "This is description for target condition.
                Vendors can write instructions for target condition 
                that vendor made";
            }
            
            container device-sec-context-cond {
              description 
                "The device attribute that can identify a device,
                 including the device type (i.e., router, switch,
                 pc, ios, or android) and the device's owner as
                 well.";

              leaf pc {
                type boolean;
                description 
                  "If type of a device is PC.";
              }

              leaf mobile-phone {
                type boolean;
                description 
                  "If type of a device is mobile-phone.";
              }
              
              leaf voip-volte-phone {
                type boolean;
                description 
                  "If type of a device is voip-volte-phone.";
              } 

              leaf tablet {
                type boolean;
                description 
                  "If type of a device is tablet.";
              }

              
              leaf iot {
                type boolean;
                description 
                  "If type of a device is Internet of Things.";
              } 
              
              leaf vehicle {
                type boolean;
                description 
                  "If type of a device is vehicle.";
              }               
            }  
          }
          container users-condition {
            description
              "TBD";
            leaf users-description {
              type string;
              description
                "This is description for user condition.
                Vendors can write instructions for user condition 
                that vendor made";
            }
            
            container user{
              description 
                "The user (or user group) information with which
                 network flow is associated: The user has many 
                 attributes such as name, id, password, type, 
                 authentication mode and so on. Name/id is often 
                 used in the security policy to identify the user.
                 Besides, NSF is aware of the IP address of the 
                 user provided by a unified user management system
                 via network. Based on name-address association,
                 NSF is able to enforce the security functions 
                 over the given user (or user group)";

              choice user-name {
                description 
                  "The name of the user.
                   This must be unique.";

                case tenant {
                  description 
                    "Tenant information.";

                  leaf tenant {
                    type uint8;
                    mandatory true;
                    description 
                      "User's tenant information.";
                  }
                }

                case vn-id {
                  description 
                    "VN-ID information.";

                  leaf vn-id {
                    type uint8;
                    mandatory true;
                    description
                      "User's VN-ID information.";
                  }
                }
              }
            }
            container group {
              description 
                "The user (or user group) information with which
                 network flow is associated: The user has many 
                 attributes such as name, id, password, type, 
                 authentication mode and so on. Name/id is often 
                 used in the security policy to identify the user.
                 Besides, NSF is aware of the IP address of the 
                 user provided by a unified user management system
                 via network. Based on name-address association,
                 NSF is able to enforce the security functions 
                 over the given user (or user group)";

              choice group-name {
                description 
                  "The name of the user.
                   This must be unique.";

                case tenant {
                  description 
                    "Tenant information.";

                  leaf tenant {
                    type uint8;
                    mandatory true;
                    description 
                      "User's tenant information.";
                  }
                }

                case vn-id {
                  description 
                    "VN-ID information.";

                  leaf vn-id {
                    type uint8;
                    mandatory true;
                    description
                      "User's VN-ID information.";
                  }
                }
              }
            }
            leaf security-grup {
              type string;
              mandatory true;
              description
                "security-grup.";
            }
          }
          
          container url-category-condition {
            description
              "TBD";          
            leaf url-category-description {
              type string;
              description
                "This is description for url category condition.
                Vendors can write instructions for context condition 
                that vendor made";
            }
            
            leaf-list pre-defined-category {
              type string;
              description
                "This is pre-defined-category.";
            }
            leaf-list user-defined-category {
              type string;
              description
                "This user-defined-category.";
            }               
          } 
          
          container context-condition {
            description
              "TBD";
            leaf context-description {
              type string;
              description
                "This is description for context condition.
                Vendors can write instructions for context condition 
                that vendor made";
            }
          }
          
          container gen-context-condition {
            description
              "TBD";
            leaf gen-context-description {
              type string;
              description
                "This is description for generic context condition.
                Vendors can write instructions for generic context 
                condition that vendor made";
            }

            container geographic-location {
              description
                "The location where network traffic is associated
                 with. The region can be the geographic location 
                 such as country, province, and city, 
                 as well as the logical network location such as 
                 IP address, network section, and network domain.";

              leaf-list src-geographic-location {
                type uint32;
                description
                  "This is mapped to ip address. We can acquire 
                   source region through ip address stored the 
                   database.";
              }
              leaf-list dest-geographic-location {
                type uint32;
                description
                  "This is mapped to ip address. We can acquire 
                   destination region through ip address stored 
                   the database.";
              }
            }           
          }
       }
      }
      container action-clause-container {
        description "TBD";
        list action-clause-list {
        key eca-object-id;
        uses i2nsf-eca-object-type {
          refine entity-class {
            default ECA-ACTION-TYPE;
          }
        }
        description 
          "An action is used to control and monitor aspects of
           flow-based NSFs when the event and condition clauses 
           are satisfied. NSFs provide security functions by 
           executing various Actions. Examples of I2NSF Actions 
           include providing intrusion detection and/or protection, 
           web and flow filtering, and deep packet inspection 
           for packets and flows.";
  
          leaf rule-log {
            type boolean;
            description
              "True is enable
               False is not enable.";
          }
          leaf session-log {
            type boolean;
            description
              "True is enable
               False is not enable.";
          }
          container ingress-action {
            description
              "TBD";
            leaf ingress-description {
              type string;
              description
                "This is description for ingress action.
                Vendors can write instructions for ingress action 
                that vendor made";
            }
            leaf ingress-action-type {
              type ingress-action;
              description
                "Ingress action type: permit, deny, and mirror.";
            }
          }
          container egress-action {
            description
              "TBD";
            leaf egress-description {
              type string;
              description
                "This is description for egress action.
                Vendors can write instructions for egress action 
                that vendor made";
            }
            leaf egress-action-type {
              type egress-action;
              description
                "Egress-action-type: invoke-signaling,
                 tunnel-encapsulation, and forwarding.";
            }
          } 
          
          container apply-profile {
            description
              "TBD";
            leaf profile-description {
              type string;
              description
                "This is description for apply profile action.
                Vendors can write instructions for apply 
                profile action that vendor made";
            }
              
              container content-security-control {
                description
                 "Content security control is another category of 
                 security capabilities applied to application layer.
                 Through detecting the contents carried over the 
                 traffic in application layer, these capabilities
                 can realize various security purposes, such as 
                 defending against intrusion, inspecting virus, 
                 filtering malicious URL or junk email, and blocking 
                 illegal web access or data retrieval.";
            
                container content-security-control-types {
                  description
                   "Content Security types: Antivirus, IPS, IDS, 
                    url-filtering, data-filtering, mail-filtering,
                    file-blocking, file-isolate, pkt-capture,
                    application-control, and voip-volte.";
            
                  leaf antivirus {
                      type string;
                      description 
                        "Additional inspection of antivirus.";
                  }
            
                  leaf ips {
                      type string;
                      description
                        "Additional inspection of IPS.";
                  }
            
                  leaf ids {
                      type string;
                      description
                        "Additional inspection of IDS.";
                  }
            
                  leaf url-filtering {
                      type string;
                      description 
                        "Additional inspection of URL filtering.";
                  }
            
                  leaf data-filtering {
                     type string;
                     description 
                       "Additional inspection of data filtering.";
                  }
            
                  leaf mail-filtering {
                    type string;
                    description 
                      "Additional inspection of mail filtering.";
                  }
            
                  leaf file-blocking {
                    type string;
                    description 
                      "Additional inspection of file blocking.";
                  }
            
                  leaf file-isolate {
                    type string;
                    description 
                      "Additional inspection of file isolate.";
                  }
            
                  leaf pkt-capture {
                    type string;
                    description 
                      "Additional inspection of packet capture.";
                  }
            
                  leaf application-control {
                    type string;
                    description 
                      "Additional inspection of app control.";
                  }
            
                  leaf voip-volte {
                    type string;
                    description 
                      "Additional inspection of VoIP/VoLTE.";
                  }
                }
              }
            
              container attack-mitigation-control {
                description
                  "This category of security capabilities is 
                   specially used to detect and mitigate various
                   types of network attacks.";
            
                  container ddos-attack {
                    description
                      "A distributed-denial-of-service (DDoS) is 
                       where the attack source is more than one, 
                       often thousands of unique IP addresses.";
            
                    container ddos-attack-type {
                      description
                        "DDoS-attack types: Network Layer 
                        DDoS Attacks and Application Layer
                        DDoS Attacks.";
            
                      container network-layer-ddos-attack {
                        description
                          "Network layer DDoS-attack.";
                        container network-layer-ddos-attack-type {
                          description
                            "Network layer DDoS attack types: 
                             Syn Flood Attack, UDP Flood Attack,
                             ICMP Flood Attack, IP Fragment Flood, 
                             IPv6 Related Attacks, and etc";
            
                          leaf syn-flood {
                            type string;
                            description
                              "Additional Inspection of 
                               Syn Flood Attack.";
                          }
            
                          leaf udp-flood {
                            type string;
                            description
                              "Additional Inspection of 
                               UDP Flood Attack.";
                          }
            
                          leaf icmp-flood {
                            type string;
                            description
                              "Additional Inspection of 
                               ICMP Flood Attack.";
                          }
            
                          leaf ip-frag-flood {
                            type string;
                            description
                              "Additional Inspection of 
                               IP Fragment Flood.";
                          }
            
                          leaf ipv6-related {
                            type string;
                            description
                              "Additional Inspection of 
                               IPv6 Related Attacks.";
                          }
                        }
                      }
            
                      container app-layer-ddos-attack {
                        description
                          "Application layer DDoS-attack.";
            
                        container app-ddos-attack-types {
                          description
                            "Application layer DDoS-attack types: 
                             Http Flood Attack, Https Flood Attack, 
                             DNS Flood Attack, and 
                             DNS Amplification Flood Attack,
                             SSL DDoS Attack, and etc.";
            
                          leaf http-flood {
                            type string;
                            description
                              "Additional Inspection of 
                               Http Flood Attack.";
                          }
            
                          leaf https-flood {
                            type string;
                            description
                              "Additional Inspection of 
                               Https Flood Attack.";
                          }
            
                          leaf dns-flood {
                            type string;
                            description
                              "Additional Inspection of 
                               DNS Flood Attack.";
                          }
            
                          leaf dns-amp-flood {
                            type string;
                            description
                              "Additional Inspection of 
                               DNS Amplification Flood Attack.";
                          }
            
                          leaf ssl-ddos {
                            type string;
                            description
                              "Additional Inspection of 
                               SSL Flood Attack.";
                          }
                        }
                      }
                    }
                  }
            
                  container single-packet-attack {
                    description
                      "Single Packet Attacks.";
                    container single-packet-attack-type {
                      description
                        "DDoS-attack types: Scanning Attack, 
                         Sniffing Attack, Malformed Packet Attack,
                         Special Packet Attack, and etc.";
            
                      container scan-and-sniff-attack {
                        description
                          "Scanning and Sniffing Attack.";
                        container scan-and-sniff-attack-types {
                          description
                            "Scanning and sniffing attack types: 
                             IP Sweep attack, Port Scanning, 
                             and etc.";
            
                          leaf ip-sweep {
                            type string;
                            description
                              "Additional Inspection of 
                               IP Sweep Attack.";
                          }
            
                          leaf port-scanning {
                            type string;
                            description
                              "Additional Inspection of 
                               Port Scanning Attack.";
                          }
                        }
                      }
            
                      container malformed-packet-attack {
                        description
                          "Malformed Packet Attack.";
                        container malformed-packet-attack-types {
                          description
                            "Malformed packet attack types: 
                             Ping of Death Attack, Teardrop Attack, 
                             and etc.";
            
                          leaf ping-of-death {
                            type string;
                            description
                              "Additional Inspection of 
                               Ping of Death Attack.";
                          }
            
                          leaf teardrop {
                            type string;
                            description
                              "Additional Inspection of 
                               Teardrop Attack.";
                          }
                        }
                      }
            
                      container special-packet-attack {
                        description
                          "special Packet Attack.";
                        container special-packet-attack-types {
                          description
                            "Special packet attack types: 
                             Oversized ICMP Attack, Tracert Attack,
                             and etc.";
            
                          leaf oversized-icmp {
                            type string;
                            description
                              "Additional Inspection of 
                               Oversize ICMP Attack.";
                          }
            
                          leaf tracert {
                            type string;
                            description
                              "Additional Inspection of 
                               Tracrt Attack.";
                          }
                        }
                      }
                    }
                  }
              }                
          }        
      } 
    }       
        
      }
        container resolution-strategy {
          description 
            "The resolution strategies can be used to
            specify how to resolve conflicts that occur between 
            the actions of the same or different policy rules that 
            are matched and contained in this particular NSF";
        
              
          choice resolution-strategy-type {
            description
              "Vendors can use YANG data model to configure rules";
        
            case fmr {
              leaf first-matching-rule {
                type boolean;
                description
                  "If the resolution strategy is first matching rule";
              }
            }
            case lmr {
              leaf last-matching-rule {
                type boolean;
                description
                  "If the resolution strategy is last matching rule";
              }
            }          
        
          }               
        }
        
        container default-action {
          description 
            "This default action can be used to specify a predefined 
            action when no other alternative action was matched 
            by the currently executing I2NSF Policy Rule. An analogy 
            is the use of a default statement in a C switch statement."; 
              
          leaf default-action-type {
            type boolean;
            description
              "True is permit
               False is deny.";
          }                           
        }

        
        container rule-group {
          description 
            "This is rule group"; 
              
          list groups {
            key "group-name";
            description
              "This is a group for rules";
              
            leaf group-name {
              type string;
              description
                "This is a group for rules";            
            }
            
            container rule-range {
              description 
                "This is a rule range.";

              leaf start-rule {
                type string;
                description
                  "This is a start rule";           
              }
              leaf end-rule {
                type string;
                description
                  "This is a end rule";         
              }
            }
            leaf enable {
              type boolean;
              description
                "This is enable
                 False is not enable.";         
            }
            leaf description {
              type string;
              description
                "This is a desription for rule-group";          
            }           
          }       
        }
      }  

      }
  }                        
                            
  <CODE ENDS>
  

Figure 5: YANG Data Module of I2NSF NSF-Facing-Interface

7. Security Considerations

This document introduces no additional security threats and SHOULD follow the security requirements as stated in [RFC8329].

8. References

8.1. Normative References

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, October 2010.
[RFC8329] Lopez, D., Lopez, E., Dunbar, L., Strassner, J. and R. Kumar, "Framework for Interface to Network Security Functions", RFC 8329, February 2018.
[RFC8431] Wang, L., Chen, M., Dass, A., Ananthakrishnan, H., Kini, S. and N. Bahadur, "A YANG Data Model for Routing Information Base (RIB)", RFC RFC8431, September 2018.

8.2. Informative References

[i2nsf-advanced-nsf-dm] Pan, W. and L. Xia, "Configuration of Advanced Security Functions with I2NSF Security Controller", Internet-Draft draft-dong-i2nsf-asf-config-01, October 2018.
[i2nsf-nsf-cap-im] Xia, L., Strassner, J., Basile, C. and D. Lopez, "Information Model of NSFs Capabilities", Internet-Draft draft-ietf-i2nsf-capability-04, October 2018.
[supa-policy-info-model] Strassner, J., Halpern, J. and S. Meer, "Generic Policy Information Model for Simplified Use of Policy Abstractions (SUPA)", Internet-Draft draft-ietf-supa-generic-policy-info-model-03, May 2017.

Appendix A. Changes from draft-ietf-i2nsf-nsf-facing-interface-dm-01

The following changes are made from draft-ietf-i2nsf-nsf-facing-interface-dm-01:

Appendix B. Acknowledgments

This work was supported by Institute for Information & communications Technology Promotion (IITP) grant funded by the Korea government (MSIP) (No.R-20160222-002755, Cloud based Security Intelligence Technology Development for the Customized Security Service Provisioning).

Appendix C. Contributors

This document is made by the group effort of I2NSF working group. Many people actively contributed to this document. The following are considered co-authors:

Authors' Addresses

Jinyong Tim Kim Department of Computer Engineering Sungkyunkwan University 2066 Seobu-Ro, Jangan-Gu Suwon, Gyeonggi-Do 16419 Republic of Korea Phone: +82 10 8273 0930 EMail: timkim@skku.edu
Jaehoon Paul Jeong Department of Software Sungkyunkwan University 2066 Seobu-Ro, Jangan-Gu Suwon, Gyeonggi-Do 16419 Republic of Korea Phone: +82 31 299 4957 Fax: +82 31 290 7996 EMail: pauljeong@skku.edu URI: http://iotlab.skku.edu/people-jaehoon-jeong.php
Jung-Soo Park Electronics and Telecommunications Research Institute 218 Gajeong-Ro, Yuseong-Gu Daejeon, 34129 Republic of Korea Phone: +82 42 860 6514 EMail: pjs@etri.re.kr
Susan Hares Huawei 7453 Hickory Hill Saline, MI 48176 USA Phone: +1-734-604-0332 EMail: shares@ndzh.com
Qiushi Lin Huawei Huawei Industrial Base Shenzhen, Guangdong 518129 China EMail: linqiushi@huawei.com