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I2NSF Consumer-Facing Interface YANG Data Model
draft-ietf-i2nsf-consumer-facing-interface-dm-24

Document Type Active Internet-Draft (i2nsf WG)
Authors Jaehoon Paul Jeong , Chaehong Chung , Tae-Jin Ahn , Rakesh Kumar , Susan Hares
Last updated 2022-11-07
Stream Internet Engineering Task Force (IETF)
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draft-ietf-i2nsf-consumer-facing-interface-dm-24
I2NSF Working Group                                        J. Jeong, Ed.
Internet-Draft                                                  C. Chung
Intended status: Standards Track                 Sungkyunkwan University
Expires: 11 May 2023                                              T. Ahn
                                                           Korea Telecom
                                                                R. Kumar
                                                        Juniper Networks
                                                                S. Hares
                                                                  Huawei
                                                         7 November 2022

            I2NSF Consumer-Facing Interface YANG Data Model
            draft-ietf-i2nsf-consumer-facing-interface-dm-24

Abstract

   This document describes an information model and the corresponding
   YANG data model for the Consumer-Facing Interface of the Security
   Controller in an Interface to Network Security Functions (I2NSF)
   system in a Network Functions Virtualization (NFV) environment.  The
   information model defines various types of managed objects and the
   relationship among them needed to build the flow policies from users'
   perspective.  This information model is based on the "Event-
   Condition-Action" (ECA) policy model defined by a capability
   information model for I2NSF, and the YANG data model is defined for
   enabling different users of a given I2NSF system to define, manage,
   and monitor flow policies within an administrative domain (e.g., user
   group).

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 11 May 2023.

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Copyright Notice

   Copyright (c) 2022 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 Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   5
   3.  Information Model for Policy  . . . . . . . . . . . . . . . .   5
     3.1.  Event Sub-model . . . . . . . . . . . . . . . . . . . . .   7
     3.2.  Condition Sub-model . . . . . . . . . . . . . . . . . . .   8
     3.3.  Action Sub-model  . . . . . . . . . . . . . . . . . . . .  11
   4.  Information Model for Policy Endpoint Groups  . . . . . . . .  11
     4.1.  User-Group  . . . . . . . . . . . . . . . . . . . . . . .  12
     4.2.  Device-Group  . . . . . . . . . . . . . . . . . . . . . .  13
     4.3.  Location-Group  . . . . . . . . . . . . . . . . . . . . .  14
     4.4.  URL-Group . . . . . . . . . . . . . . . . . . . . . . . .  15
     4.5.  Voice-Group . . . . . . . . . . . . . . . . . . . . . . .  15
   5.  Information Model for Threat Prevention . . . . . . . . . . .  16
     5.1.  Threat Feed . . . . . . . . . . . . . . . . . . . . . . .  16
     5.2.  Payload Content . . . . . . . . . . . . . . . . . . . . .  17
   6.  YANG Data Model of Consumer-Facing Interface  . . . . . . . .  19
     6.1.  YANG Module of Consumer-Facing Interface  . . . . . . . .  19
   7.  XML Configuration Examples of High-Level Security Policy
           Rules . . . . . . . . . . . . . . . . . . . . . . . . . .  59
     7.1.  Database Registration: Information of Positions and Devices
           (Endpoint Group)  . . . . . . . . . . . . . . . . . . . .  59
     7.2.  Scenario 1: Block SNS Access during Business Hours  . . .  62
     7.3.  Scenario 2: Block Malicious VoIP/VoCN Packets Coming to a
           Company . . . . . . . . . . . . . . . . . . . . . . . . .  64
     7.4.  Scenario 3: Mitigate Flood Attacks on a Company Web
           Server  . . . . . . . . . . . . . . . . . . . . . . . . .  65
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  67
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .  67
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  69
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  69
     10.2.  Informative References . . . . . . . . . . . . . . . . .  73
   Appendix A.  Acknowledgments  . . . . . . . . . . . . . . . . . .  75

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   Appendix B.  Contributors . . . . . . . . . . . . . . . . . . . .  75
   Appendix C.  Changes from
           draft-ietf-i2nsf-consumer-facing-interface-dm-23  . . . .  76
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  76

1.  Introduction

   In a framework of Interface to Network Security Functions (I2NSF)
   [RFC8329], each vendor can register their Network Security Functions
   (NSFs) using a Developer's Management System (DMS).  Then the I2NSF
   User (e.g., an application for a security administrator such as a web
   application) can configure the NSFs by defining high-level security
   policies.  Most vendors provide various proprietary applications or
   tools to define security policies for their own NSFs.  The Consumer-
   Facing Interface is required because the applications developed by
   each vendor need to have a standard interface specifying the data
   types used when the I2NSF User and Security Controller (i.e., Network
   Operator Management System) communicate with each other using this
   interface.  Therefore, this document specifies the required
   information such as their data types and encoding schemes so that
   high-level security policies (or configuration information for
   security policies) can be transferred to the Security Controller
   through the Consumer-Facing Interface.  Security Controller will use
   the given information to translate the high-level security policies
   into the corresponding low-level security policies.  The Security
   Controller delivers the translated security policies to the NSFs
   according to their respective security capabilities for the required
   security enforcement.

   The Consumer-Facing Interface would be built using a set of objects,
   with each object capturing a unique set of information from an I2NSF
   User [RFC8329] needed to express a Security Policy.  An object may
   have relationship with various other objects to express a complete
   set of requirements.  An information model captures the managed
   objects and relationship among these objects.  The information model
   proposed in this document is structured in accordance with the
   "Event-Condition-Action" (ECA) policy model.

   An NSF Capability model is proposed in
   [I-D.ietf-i2nsf-capability-data-model] as the basic model for both
   the NSF-Facing interface and Consumer-Facing Interface security
   policy model of this document.

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   [RFC3444] explains differences between an information and data model.
   This document uses the guidelines in [RFC3444] to define both the
   information and data model for Consumer-Facing Interface.  Figure 1
   shows a high-level abstraction of Consumer-Facing Interface.  A data
   model, which represents an implementation of the information model in
   a specific data representation language, is also defined in this
   document.

                       +-----------------+
                       | Consumer-Facing |
                       |    Interface    |
                       +--------+--------+
                                ^
                                |
                                +-------------+------------+
                                |             |            |
                          +-----+----+  +-----+----+  +----+---+
                          |  Policy  |  | Endpoint |  | Threat |
                          |          |  |  groups  |  |  feed  |
                          +-----+----+  +----------+  +--------+
                                ^
                                |
                         +------+------+
                         |     Rule    |
                         +------+------+
                                ^
                                |
               +----------------+----------------+
               |                |                |
        +------+------+  +------+------+  +------+------+
        |    Event    |  |  Condition  |  |    Action   |
        +-------------+  +-------------+  +-------------+

      Figure 1: Diagram for High-level Abstraction of Consumer-Facing
                                 Interface

   Data models are defined at a lower level of abstraction and provide
   many details.  They provide details about the implementation of a
   protocol's specification, e.g., rules that explain how to map managed
   objects onto lower-level protocol constructs.  Since conceptual
   models can be implemented in different ways, multiple data models can
   be derived from a single information model.

   The efficient and flexible provisioning of network functions by a
   Network Functions Virtualization (NFV) system supports rapid
   deployment of newly developed functions.  As practical applications,
   Network Security Functions (NSFs), such as firewall, Intrusion

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   Detection System (IDS)/Intrusion Prevention System (IPS), and attack
   mitigation, can also be provided as Virtual Network Functions (VNF)
   in the NFV system.  By the efficient virtualization technology, these
   VNFs might be automatically provisioned and dynamically migrated
   based on real-time security requirements.  This document presents a
   YANG data model to implement security functions based on NFV.

2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

   This document uses the terminology described in [RFC8329].

   This document follows the guidelines of [RFC8407], uses the common
   YANG types defined in [RFC6991], and adopts the Network Management
   Datastore Architecture (NMDA) [RFC8342].  The meaning of the symbols
   in tree diagrams is defined in [RFC8340].

3.  Information Model for Policy

   A Policy object is a means to express a Security Policy set by an
   I2NSF User with the Consumer-Facing Interface.  It is sent to the
   Security Controller which converts it into an NSF-specific
   configuration via the NSF-Facing Interface for enforcement of the
   NSF.  Figure 2 shows the YANG tree of the Policy object.  The Policy
   object SHALL have the following information:

   Name:     This field identifies the name of this object.

   Language:  The language field indicates the language tag that is used
             for the natural language text that is included in all of
             the 'description' attributes.  The language field is
             encoded following the rules in Section 2.1 of [RFC5646].
             The default language tag is "en-US".

   Resolution-strategy:  This field represents how to resolve conflicts
             that occur between actions of the same or different policy
             rules that are matched and contained in this particular
             NSF.  The resolution strategy is described in Section 3.2
             of [I-D.ietf-i2nsf-capability-data-model] in detail.

   Rules:    This field contains a list of rules.  These rules are

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             defined for implementing business requirements such as 1)
             supporting communication between two Endpoint Groups (see
             Section 4), 2) preventing communication with externally or
             internally identified threats, and 3) controlling access to
             internal or external resources for meeting regulatory
             compliance.  An organization may restrict certain
             communication between a set of users and applications for
             example.  The threats may be identified from threat feeds
             obtained from external sources.  Note that rule conflict
             analysis should be performed by a monitoring service for
             policy rule conflicts in Security Controller to detect such
             rule conflicts among the policy rules installed into
             network security functions.

   module: ietf-i2nsf-cons-facing-interface
     +--rw i2nsf-cfi-policy* [name]
     |  +--rw name                   string
     |  +--rw language?              string
     |  +--rw resolution-strategy?   identityref
     |  +--rw rules* [name]
     |     ...
     +--rw endpoint-groups
     |  ...
     +--rw threat-prevention
        ...

                      Figure 2: Policy YANG Data Tree

   A policy contains a list of rules.  In order to express a Rule, a
   Rule must have complete information such as where and when a policy
   needs to be applied.  This is done by defining a set of managed
   objects and relationship among them.  A Policy Rule defined in this
   module is a set of management guidelines that defines a desired
   behavior based on the Event-Condition-Action policy model
   (Section 3.1 of [I-D.ietf-i2nsf-capability-data-model]), but that is
   independent of a specific device and implementation.  Figure 3 shows
   the YANG data tree of the Rule object.  The rule object SHALL have
   the following information:

   Name:     This field identifies the name of this object.

   Priority:  This field identifies the priority of the rule.

   Event:    This field includes the information to determine whether

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             the Rule Condition can be evaluated or not (see the
             definition of Event in Section 3.1 of
             [I-D.ietf-i2nsf-capability-data-model]).  See details of
             the Event Object in Section 3.1.

   Condition:  This field contains a set of attributes, features, and/or
             values that are to be matched with the attributes of a
             packet or traffic flow to determine whether the Rule Action
             can be executed or not (see Section 3.1 of
             [I-D.ietf-i2nsf-capability-data-model]).  See details of
             the Condition Object in Section 3.2.

   Action:   This field identifies the action taken when a rule is
             matched (see Section 3.1 of
             [I-D.ietf-i2nsf-capability-data-model]).  There is always
             an implicit action to drop traffic if no rule is matched
             for a traffic type.  See details of the Action Object in
             Section 3.3.

        +--rw rules* [name]
        |  +--rw name         string
        |  +--rw priority?    uint8
        |  +--rw event
        |  |  ...
        |  +--rw condition
        |  |  ...
        |  +--rw action
        |     ...

                       Figure 3: Rule YANG Data Tree

3.1.  Event Sub-model

   The Event Object contains information related to scheduling a Rule.
   The Event Object activates the evaluation of the Condition Object
   based on a security event (i.e., system event and system alarm).
   Note that an empty Event Object means that the event will always
   evaluate to true and start the evaluation of the Condition Object.
   Figure 4 shows the YANG tree of the Event object.  Event object SHALL
   have the following information:

   System-event (also called alert):  is defined as a warning about any
             changes of configuration, any access violation, the
             information of sessions and traffic flows.

   System-alarm:  is defined as a warning related to service degradation

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             in system hardware.

     +--rw event
     |  +--rw system-event*   identityref
     |  +--rw system-alarm*   identityref

                  Figure 4: Event Sub-model YANG Data Tree

3.2.  Condition Sub-model

   The Condition object describes the network traffic pattern or fields
   that must be matched against the observed network traffic for the
   rule to trigger.  The fields used to express the required conditions
   to trigger the rule are organized around the class of NSFs expected
   to be able to observe or compute them.  Figure 5 shows the YANG tree
   of the Condition object.  The Condition Sub-model SHALL have the
   following information:

   Case (firewall):  This field represents the layer-2 header (e.g., MAC
             addresses), layer-3 header (e.g., IPv4 or IPv6 addresses,
             ICMPv4 or ICMPv6 parameters, and transport layer protocol)
             and layer-4 header (e.g., port numbers) of the network
             traffic.  Note that the YANG module only provides high-
             level ICMP messages that are shared between ICMPv4 and
             ICMPv6 (e.g., Destination Unreachable: Port Unreachable
             which is ICMPv4's type 3 and code 3 or ICMPv6's type 1 and
             code 4).  Also note that QUIC protocol [RFC9000] is
             excluded in the data model as it is not considered in the
             initial I2NSF documents [RFC8329].  The QUIC traffic should
             not be treated as UDP traffic and will be considered in the
             future I2NSF documents.

   Case (ddos):  This field represents the threshold limit for the rate
             of the network traffic to mitigate a DDoS attack.  The
             threshold configuration can be given in packet rate, byte
             rate, and flow rate.  Definition of packet rate, byte rate,
             and flow rate are defined in Section 6 of
             [I-D.ietf-i2nsf-capability-data-model].

   Case (anti-virus):  This field represents the configuration for an
             Antivirus interruption.  Specific file names or types can
             be configured to be excluded from the interruption.

   Case (payload):  This field represents the payload information of the

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             network traffic.  The configuration is given in a high-
             level form that maps into the corresponding binary form
             registered with the Threat Prevention object (see
             Section 5.2).

   Case (url-category):  This field represents the URL to be filtered.
             This information can be used to block or allow a certain
             URL or website.  The url-name is a group of URL or websites
             to be matched.

   Case (voice):  This field contains the call source-id, call
             destination-id, and user-agent.  This information describes
             a caller id or receiver id in order to prevent any exploits
             (or attacks) of Voice over IP (VoIP) or Voice over Cellular
             Network (VoCN).  Note that VoCN can be either Voice over
             LTE (VoLTE) [TR-29.949-3GPP] or Voice over 5G (Vo5G)
             [TR-21.915-3GPP].

   Case (context):  This field represents the extra information for the
             condition such as time, application, device type, user
             condition, and geographic location (see Section 5.1 of
             [I-D.ietf-i2nsf-capability-data-model]).

   Case (Threat-feed):  This field contains the information obtained
             from threat-feeds.  This field is used when security rule
             condition is based on the existing threat reports gathered
             from other sources.

   Note that the identities for ICMP messages provided in the YANG
   module are combined for ICMPv4 and ICMPv6 such as echo/echo-reply for
   ICMPv4 and echo-request/echo-reply for ICMPv6.  For more information
   about the mapping between ICMPv4 and ICMPv6 messages, refer to
   [IANA-ICMP-Parameters] and [IANA-ICMPv6-Parameters].

 +--rw condition
 |  +--rw firewall
 |  |  +--rw source*                     union
 |  |  +--rw destination*                union
 |  |  +--rw transport-layer-protocol?   identityref
 |  |  +--rw range-port-number* [start end]
 |  |  |  +--rw start    inet:port-number
 |  |  |  +--rw end      inet:port-number
 |  |  +--rw icmp
 |  |     +--rw message*   identityref
 |  +--rw ddos
 |  |  +--rw rate-limit
 |  |     +--rw packet-rate-threshold?   uint64
 |  |     +--rw byte-rate-threshold?     uint64

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 |  |     +--rw flow-rate-threshold?     uint64
 |  +--rw anti-virus
 |  |  +--rw exception-files*   string
 |  +--rw payload
 |  |  +--rw content*   -> /threat-prevention/payload-content/name
 |  +--rw url-category
 |  |  +--rw url-name?   -> /endpoint-groups/url-group/name
 |  +--rw voice
 |  |  +--rw source-id*        -> /endpoint-groups/voice-group/name
 |  |  +--rw destination-id*   -> /endpoint-groups/voice-group/name
 |  |  +--rw user-agent*       string
 |  +--rw context
 |  |  +--rw time
 |  |  |  +--rw start-date-time?   yang:date-and-time
 |  |  |  +--rw end-date-time?     yang:date-and-time
 |  |  |  +--rw period
 |  |  |  |  +--rw start-time?   time
 |  |  |  |  +--rw end-time?     time
 |  |  |  |  +--rw day*          day
 |  |  |  |  +--rw date*         int8
 |  |  |  |  +--rw month*        string
 |  |  |  +--rw frequency?         enumeration
 |  |  +--rw application
 |  |  |  +--rw protocol*   identityref
 |  |  +--rw device-type
 |  |  |  +--rw device*   identityref
 |  |  +--rw users
 |  |  |  +--rw user* [id]
 |  |  |  |  +--rw id      uint32
 |  |  |  |  +--rw name?   string
 |  |  |  +--rw group* [id]
 |  |  |     +--rw id      uint32
 |  |  |     +--rw name?   string
 |  |  +--rw geographic-location
 |  |     +--rw source
 |  |     |  +--rw country?   -> /endpoint-groups/location-group/country
 |  |     |  +--rw region?    -> /endpoint-groups/location-group/region
 |  |     |  +--rw city?      -> /endpoint-groups/location-group/city
 |  |     +--rw destination
 |  |        +--rw country?   -> /endpoint-groups/location-group/country
 |  |        +--rw region?    -> /endpoint-groups/location-group/region
 |  |        +--rw city?      -> /endpoint-groups/location-group/city
 |  +--rw threat-feed
 |     +--rw name*   -> /threat-prevention/threat-feed-list/name

             Figure 5: Condition Sub-model YANG Data Tree

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3.3.  Action Sub-model

   This object represents actions that Security Admin wants to perform
   based on certain traffic class.  Figure 6 shows the YANG tree of the
   Action object.  The Action object SHALL have following information:

   Primary-action:  This field identifies the action when a rule is
             matched by an NSF.  The action could be one of "pass",
             "drop", "reject", "rate-limit", "mirror", "invoke-
             signaling", "tunnel-encapsulation", "forwarding", and
             "transformation".  This action is related to the ingress-
             action-capability and egress-action-capability in
             [I-D.ietf-i2nsf-capability-data-model].  Note that if the
             action is "rate-limit", the limit value should be given to
             Security Controller in order to determine the threshold of
             the traffic rate.

   Secondary-action:  This field identifies the action when a rule is
             matched by an NSF.  The action could be one of "rule-log"
             and "session-log".  This action is related to the log-
             action in [I-D.ietf-i2nsf-capability-data-model].

     +--rw action
        +--rw primary-action
        |  +--rw action    identityref
        |  +--rw limit?    decimal64
        +--rw secondary-action
           +--rw log-action?   identityref

                 Figure 6: Action Sub-model YANG Data Tree

4.  Information Model for Policy Endpoint Groups

   The Policy Endpoint Group is the collection of network nodes that are
   labeled and placed together into a group.  As shown in Figure 7,
   endpoint groups include User-Group (Section 4.1), Device-Group
   (Section 4.2), Location-Group (Section 4.3), and URL-Group
   (Section 4.4).  An I2NSF User can create and use these objects to
   represent a logical entity in their business environment, where a
   security policy is to be applied.  Figure 8 shows the YANG tree of
   the Endpoint-Groups object.

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   The endpoint group information delivered by the I2NSF User should be
   stored into a secure database available to the Security Controller
   for the translation from a high-level security policy to the
   corresponding low-level security policy.  The information should be
   synchronized with other systems in real-time for accurate
   translation.

                            +-------------------+
                            |  Endpoint Groups  |
                            +---------+---------+
                                      ^
                                      |
        +-------------+---------------+--------------+-----------+
   0..n |        0..n |          0..n |         0..n |      0..n |
  +-----+----+ +------+-----+ +-------+------+ +-----+---+ +-----+-----+
  |User-group| |Device-group| |Location-group| |URL-group| |Voice-group|
  +----------+ +------------+ +--------------+ +---------+ +-----------+

                    Figure 7: Endpoint Group Diagram

     +--rw endpoint-groups
     |  +--rw user-group* [name]
     |  |  ...
     |  +--rw device-group* [name]
     |  |  ...
     |  +--rw location-group* [country region city]
     |  |  ...
     |  +--rw url-group* [name]
     |  |  ...
     |  +--rw voice-group* [name]
     |     ...

                  Figure 8: Endpoint Group YANG Data Tree

4.1.  User-Group

   The User-Group object represents the MAC addresses and IP (IPv4 or
   IPv6) addresses that are labeled as a group of users (e.g.,
   employees).  Figure 9 shows the YANG tree of the User-Group object.
   The User-Group object SHALL have the following information:

   Name:     This field identifies the name of the user-group.

   mac-address:  This represents the MAC address(es) for the user-group.

   Range-ipv4-address:  This represents the list of IPv4 address ranges

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             for the user-group.

   Range-ipv6-address:  This represents the list of IPv6 address ranges
             for the user-group.

    +--rw user-group* [name]
    |  +--rw name                        string
    |  +--rw mac-address*                yang:mac-address
    |  +--rw (match-type)
    |     +--:(range-match-ipv4)
    |     |  +--rw range-ipv4-address* [start end]
    |     |     +--rw start    inet:ipv4-address-no-zone
    |     |     +--rw end      inet:ipv4-address-no-zone
    |     +--:(range-match-ipv6)
    |        +--rw range-ipv6-address* [start end]
    |           +--rw start    inet:ipv6-address-no-zone
    |           +--rw end      inet:ipv6-address-no-zone

                    Figure 9: User-Group YANG Data Tree

4.2.  Device-Group

   The Device-Group object represents the labeled network devices that
   provide services (e.g., servers) hosted on the IP (IPv4 or IPv6)
   addresses and application protocol.  Figure 10 shows the YANG tree of
   the Device-group object.  The Device-Group object SHALL have the
   following information:

   Name:     This field identifies the name of this object.

   Range-ipv4-address:  This represents the list of IPv4 address ranges
             for the device-group.

   Range-ipv6-address:  This represents the list of IPv6 address ranges
             for the device-group.

   Application-protocol:  This represents the application layer
             protocols of devices for the device-group.

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    +--rw device-group* [name]
    |  +--rw name                        string
    |  +--rw (match-type)
    |  |  +--:(range-match-ipv4)
    |  |  |  +--rw range-ipv4-address* [start end]
    |  |  |     +--rw start    inet:ipv4-address-no-zone
    |  |  |     +--rw end      inet:ipv4-address-no-zone
    |  |  +--:(range-match-ipv6)
    |  |     +--rw range-ipv6-address* [start end]
    |  |        +--rw start    inet:ipv6-address-no-zone
    |  |        +--rw end      inet:ipv6-address-no-zone
    |  +--rw application-protocol*       identityref

                   Figure 10: Device-Group YANG Data Tree

4.3.  Location-Group

   The Location-Group object represents the IP (IPv4 or IPv6) addresses
   labeled as a geographic location (i.e., country, region, and city)
   [RFC8805].  Figure 11 shows the YANG tree of the Location-Group
   object.  The Location-Group object SHALL have the following
   information:

   Country:  This field represents the 2-letter ISO country code
             conforming to ISO3166-1 alpha 2, e.g., 'US' for United
             States, 'JP' for Japan, and 'PL' for Poland.

   Region:   This field represents the region code conforming to ISO
             3166-2.  Examples include 'ID-RI' for Riau province of
             Indonesia and 'NG-RI' for the Rivers province in Nigeria.

   City:     This field represents the city of a region, e.g., 'Dublin',
             'New York', and 'Sao Paulo'.

   Range-ipv4-address:  This represents the list of IPv4 address range
             of a geographic location in the location group.

   Range-ipv6-address:  This represents the list of IPv6 address range
             of a geographic location in the location group.

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    +--rw location-group* [country region city]
    |  +--rw country                     string
    |  +--rw region                      string
    |  +--rw city                        string
    |  +--rw (match-type)
    |     +--:(range-match-ipv4)
    |     |  +--rw range-ipv4-address* [start end]
    |     |     +--rw start    inet:ipv4-address-no-zone
    |     |     +--rw end      inet:ipv4-address-no-zone
    |     +--:(range-match-ipv6)
    |        +--rw range-ipv6-address* [start end]
    |           +--rw start    inet:ipv6-address-no-zone
    |           +--rw end      inet:ipv6-address-no-zone

                  Figure 11: Location-Group YANG Data Tree

4.4.  URL-Group

   The URL-Group object represents the collection of Uniform Resource
   Locators (URLs) or hostnames labeled into a group (e.g., sns-
   websites).  Figure 12 shows the YANG tree of the URL-Group object.
   The URL-Group object SHALL have the following information:

   Name:     This field identifies the name of this object.

   URL:      This field represents the URL or hostname.

    +--rw url-group* [name]
    |  +--rw name    string
    |  +--rw url*    inet:uri

                    Figure 12: URL-Group YANG Data Tree

4.5.  Voice-Group

   The Voice-Group object represents the collection of Session
   Initiation Protocol (SIP) identities labeled into a group.  Figure 13
   shows the YANG tree of the Voice-Group object.  The Voice-Group
   object SHALL have the following information:

   Name:     This field identifies the name of this object.

   SIP-id:   This field represents the SIP identities in SIP URI scheme
             (Section 19.1.1 of [RFC3261]).

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     +--rw voice-group* [name]
        +--rw name      string
        +--rw sip-id*   inet:uri

                   Figure 13: Voice-Group YANG Data Tree

5.  Information Model for Threat Prevention

   The Threat Prevention model describes information obtained from
   threat feeds (i.e., sources for obtaining the threat information).
   The presented information is the features or attributes that identify
   a well-known threat (e.g., signatures or payload) to prevent
   malicious activity entering the secured network.  There are multiple
   managed objects that constitute this category.  Figure 15 shows the
   YANG tree of a Threat-Prevention object.

                      +-------------------+
                      | Threat Prevention |
                      +---------+---------+
                                ^
                                |
                      +---------+---------+
              0..n    |         0..n      |
               +------+------+   +--------+--------+
               | Threat-feed |   | Payload-content |
               +-------------+   +-----------------+

                    Figure 14: Threat Prevention Diagram

     +--rw threat-prevention
        +--rw threat-feed-list* [name]
        |  ...
        +--rw payload-content* [name]
           ...

                Figure 15: Threat Prevention YANG Data Tree

5.1.  Threat Feed

   This object represents a threat feed which provides the signatures of
   malicious activities.  Figure 16 shows the YANG tree of a Threat-
   feed-list.  The Threat-Feed object SHALL have the following
   information:

   Name:     This field identifies the name of this object.

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   IOC:      This field represents the Indicators of Compromise (IOC),
             i.e., the critical information of patterns or
             characteristics in the threat feed that identifies
             malicious activities.  The format of the information given
             in this field is based on the format field (e.g., STIX,
             MISP, and OpenIOC).

   Format:   This field represents the format or structure of the IOC
             field for the threat-feed such as Structured Threat
             Information Expression (STIX) [STIX], MISP Core [MISPCORE],
             and OpenIOC [OPENIOC].  This can be extended depending on
             the implementation of the existing threat-feed.

   It is assumed that the I2NSF User obtains the threat signatures
   (i.e., threat content patterns) from a threat-feed server (i.e., feed
   provider), which is a server providing threat signatures.  With the
   obtained threat signatures, the I2NSF User can deliver them to the
   Security Controller via the Consumer-Facing Interface.  The retrieval
   of the threat signatures by the I2NSF User is out of the scope of
   this document.

        +--rw threat-feed-list* [name]
        |  +--rw name      string
        |  +--rw ioc*      string
        |  +--rw format    identityref

                   Figure 16: Threat Feed YANG Data Tree

5.2.  Payload Content

   This object represents a list of raw binary patterns of a packet
   payload content (i.e., data after a transport layer header) to
   describe a threat.  Figure 17 shows the YANG tree of a Payload-
   content list.  The Payload-content object SHALL have the following
   information:

   Name:     This field identifies the name of this object.  It is
             recommended to use short and simple words that describe the
             content.  For example, the name "backdoor" indicates the
             payload content is related to a backdoor attack.

   Description:  This represents the description to further describe the
             content field in detail.  This field is not mandatory but
             recommended to be used as it is helpful for future usage.

   Content:  This represents the payload content patterns (i.e., data

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             after a transport layer header), which are involved in a
             security attack, in binary.  If multiple instances of
             content are defined, it should match all contents somewhere
             in the session stream.  The content pattern should be
             matched based on the order given by the user.  The scope of
             the payload to be matched can be defined by the depth and
             offset/distance fields.

   Depth:    This field specifies how far a packet should be searched
             for the specified content pattern defined in the content
             field.  If this field is undefined, then the content
             pattern should be searched within the whole payload.

   Starting-point:  This field specifies the starting point of matching
             the content pattern to the payload.  If this field is
             undefined, then the content pattern should be searched from
             the beginning of the payload.  The starting point can be
             defined by either the offset value or distance value.  The
             offset keyword specifies where to start searching for the
             specified content pattern.  The offset is calculated from
             the beginning of the payload.  The distance keyword
             specifies how far a payload should be ignored before
             starting to search for the specified content pattern
             relative to the end of the previous specified content
             pattern match.  This can be thought of as exactly the same
             thing as offset, except it is relative to the end of the
             last pattern match instead of the beginning of the packet.
             Note that this field cannot be used if the content is the
             first order of the list.

        +--rw payload-content* [name]
           +--rw name           string
           +--rw description?   string
           +--rw contents* [content]
              +--rw content           binary
              +--rw depth?            uint16
              +--rw (starting-point)?
                 +--:(offset)
                 |  +--rw offset?     int32
                 +--:(distance)
                    +--rw distance?   int32

                Figure 17: Payload Content in YANG Data Tree

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6.  YANG Data Model of Consumer-Facing Interface

   The main objective of this document is to provide the YANG data model
   of the I2NSF Consumer-Facing Interface.  This interface can be used
   to deliver control and management messages between an I2NSF User and
   Security Controller for the I2NSF User's high-level security
   policies.

   The semantics of the data model is aligned with the information model
   of the Consumer-Facing Interface.  This data model is designed to
   support the I2NSF framework that can be extended according to the
   security needs.  In other words, the model design is independent of
   the content and meaning of specific policies as well as the
   implementation approach.

   With the YANG data model of I2NSF Consumer-Facing Interface, this
   document provide examples for security policy rules such as time-
   based firewall, VoIP/VoCN security service, and DDoS-attack
   mitigation in Section 7.

6.1.  YANG Module of Consumer-Facing Interface

   This section describes a YANG module of Consumer-Facing Interface.
   This document provides identities in the data model to be used for
   configuration of an NSF.  Each identity is used for a different type
   of configuration.  The details are explained in the description of
   each identity.  This YANG module imports from [RFC6991].  It makes
   references to [RFC0768] [RFC0792] [RFC0854] [RFC0959] [RFC1939]
   [RFC2595] [RFC3022] [RFC3261] [RFC3986] [RFC4250] [RFC4340] [RFC4443]
   [RFC5321] [RFC5646] [RFC8075] [RFC8335] [RFC8805] [RFC9051] [RFC9110]
   [RFC9112] [RFC9113] [RFC9260] [RFC9293] [GLOB] [IANA-ICMP-Parameters]
   [IANA-ICMPv6-Parameters] [ISO-3166-1alpha2] [ISO-3166-2]
   [I-D.ietf-i2nsf-capability-data-model]
   [I-D.ietf-i2nsf-nsf-monitoring-data-model] [MISPCORE] [OPENIOC]
   [STIX]

   <CODE BEGINS> file "ietf-i2nsf-cons-facing-interface@2022-11-07.yang"
   module ietf-i2nsf-cons-facing-interface {
     yang-version 1.1;
     namespace
       "urn:ietf:params:xml:ns:yang:ietf-i2nsf-cons-facing-interface";
     prefix
       i2nsfcfi;

     import ietf-inet-types{
       prefix inet;
       reference "RFC 6991";
     }

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     import ietf-yang-types{
       prefix yang;
       reference "RFC 6991";
     }

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

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

        Editor: Jaehoon Paul Jeong
        <mailto:pauljeong@skku.edu>

        Editor: Patrick Lingga
        <mailto:patricklink@skku.edu>";

     description
       "This module is a YANG module for Consumer-Facing Interface.

        Copyright (c) 2022 IETF Trust and the persons identified as
        authors of the code. All rights reserved.

        Redistribution and use in source and binary forms, with or
        without modification, is permitted pursuant to, and subject to
        the license terms contained in, the Revised BSD License set
        forth in Section 4.c of the IETF Trust's Legal Provisions
        Relating to IETF Documents
        (https://trustee.ietf.org/license-info).

        This version of this YANG module is part of RFC XXXX
        (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself
        for full legal notices.";

     // RFC Ed.: replace XXXX with an actual RFC number and remove
     // this note.

     revision "2022-11-07" {
       description "Initial revision.";
       reference
         "RFC XXXX: I2NSF Consumer-Facing Interface YANG Data Model";

       // RFC Ed.: replace XXXX with an actual RFC number and remove
       // this note.
     }

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     identity resolution-strategy {
       description
         "Base identity for resolution strategy";
       reference
         "draft-ietf-i2nsf-capability-data-model-32:
          I2NSF Capability YANG Data Model - Resolution Strategy";
     }

     identity fmr {
       base resolution-strategy;
       description
         "Conflict resolution with First Matching Rule (FMR).";
       reference
         "draft-ietf-i2nsf-capability-data-model-32:
          I2NSF Capability YANG Data Model - Resolution Strategy";
     }

     identity lmr {
       base resolution-strategy;
       description
         "Conflict resolution with Last Matching Rule (LMR)";
       reference
         "draft-ietf-i2nsf-capability-data-model-32:
          I2NSF Capability YANG Data Model - Resolution Strategy";
     }

     identity pmre {
       base resolution-strategy;
       description
         "Conflict resolution with Prioritized Matching Rule with
          Errors (PMRE)";
       reference
         "draft-ietf-i2nsf-capability-data-model-32:
          I2NSF Capability YANG Data Model - Resolution Strategy";
     }

     identity pmrn {
       base resolution-strategy;
       description
         "Conflict resolution with Prioritized Matching Rule with
          No Errors (PMRN)";
       reference
         "draft-ietf-i2nsf-capability-data-model-32:
          I2NSF Capability YANG Data Model - Resolution Strategy";
     }

     identity event {
       description

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         "Base identity for policy events.";
       reference
         "draft-ietf-i2nsf-nsf-monitoring-data-model-20: I2NSF NSF
          Monitoring Interface YANG Data Model - Event";
     }

     identity system-event {
       base event;
       description
         "Base Identity for system events. System event (also called
          alert) is defined as a warning about any changes of
          configuration, any access violation, the information of
          sessions and traffic flows.";
       reference
         "draft-ietf-i2nsf-nsf-monitoring-data-model-20: I2NSF NSF
          Monitoring Interface YANG Data Model - System event";
     }

     identity system-alarm {
       base event;
       description
         "Base identity for system alarms. System alarm is defined as a
          warning related to service degradation in system hardware.";
       reference
         "draft-ietf-i2nsf-nsf-monitoring-data-model-20: I2NSF NSF
          Monitoring Interface YANG Data Model - System alarm";
     }

     identity access-violation {
       base system-event;
       description
         "Access-violation system event is an event when a user tries
          to access (read, write, create, or delete) any information or
          execute commands above their privilege (i.e., not-conformant
          with the access profile).";
       reference
         "draft-ietf-i2nsf-nsf-monitoring-data-model-20: I2NSF NSF
          Monitoring Interface YANG Data Model - System event for access
          violation";
     }

     identity configuration-change {
       base system-event;
       description
         "The configuration-change system event is an event when a user
          adds a new configuration or modify an existing configuration
          (write configuration).";
       reference

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         "draft-ietf-i2nsf-nsf-monitoring-data-model-20: I2NSF NSF
          Monitoring Interface YANG Data Model - System event for
          configuration change";
     }

     identity memory-alarm {
       base system-alarm;
       description
         "Memory is the hardware to store information temporarily or for
          a short period, i.e., Random Access Memory (RAM). A
          memory-alarm is emitted when the memory usage is exceeding
          the threshold.";
       reference
         "draft-ietf-i2nsf-nsf-monitoring-data-model-20: I2NSF NSF
          Monitoring Interface YANG Data Model - System alarm for
          memory";
     }

     identity cpu-alarm {
       base system-alarm;
       description
         "CPU is the Central Processing Unit that executes basic
          operations of the system. A cpu-alarm is emitted when the CPU
          usage is exceeding a threshold.";
       reference
         "draft-ietf-i2nsf-nsf-monitoring-data-model-20: I2NSF NSF
          Monitoring Interface YANG Data Model - System alarm for CPU";
     }

     identity disk-alarm {
       base system-alarm;
       description
         "Disk or storage is the hardware to store information for a
          long period, i.e., Hard Disk and Solid-State Drive. A
          disk-alarm is emitted when the disk usage is exceeding a
          threshold.";
       reference
         "draft-ietf-i2nsf-nsf-monitoring-data-model-20: I2NSF NSF
          Monitoring Interface YANG Data Model - System alarm for disk";
     }

     identity hardware-alarm {
       base system-alarm;
       description
         "A hardware alarm is emitted when a hardware failure (e.g.,
          CPU, memory, disk, or interface) is detected. A hardware
          failure is a malfunction within the electronic circuits or
          electromechanical components of the hardware that makes it

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          unusable.";
       reference
         "draft-ietf-i2nsf-nsf-monitoring-data-model-20: I2NSF NSF
          Monitoring Interface YANG Data Model - System alarm for
          hardware";
     }

     identity interface-alarm {
       base system-alarm;
       description
         "Interface is the network interface for connecting a device
          with the network. The interface-alarm is emitted when the
          state of the interface is changed.";
       reference
         "draft-ietf-i2nsf-nsf-monitoring-data-model-20: I2NSF NSF
          Monitoring Interface YANG Data Model - System alarm for
          interface";
     }

     identity protocol {
       description
         "This identity represents the protocol types.";
     }

     identity transport-protocol {
       base protocol;
       description
         "Base identity for the Layer 4 (i.e., Transport Layer)
         Protocols";
     }

     identity tcp {
       base transport-protocol;
       description
         "Base identity for TCP condition capabilities";
       reference
         "RFC 9293: Transmission Control Protocol";
     }

     identity udp {
       base transport-protocol;
       description
         "Base identity for UDP condition capabilities";
       reference
         "RFC 768: User Datagram Protocol";
     }

     identity sctp {

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       base transport-protocol;
       description
         "Identity for SCTP condition capabilities";
       reference
         "RFC 9260: Stream Control Transmission Protocol";
     }

     identity dccp {
       base transport-protocol;
       description
         "Identity for DCCP condition capabilities";
       reference
         "RFC 4340: Datagram Congestion Control Protocol";
     }

     identity application-protocol {
       description
         "Base identity for Application protocol. Note that a subset of
          application protocols (e.g., HTTP, HTTPS, FTP, POP3, and
          IMAP) are handled in this YANG module, rather than all
          the existing application protocols.";
     }

     identity http {
       base application-protocol;
       description
         "The identity for Hypertext Transfer Protocol version 1.1
          (HTTP/1.1).";
       reference
         "RFC 9110: HTTP Semantics
          RFC 9112: HTTP/1.1";
     }

     identity https {
       base application-protocol;
       description
         "The identity for Hypertext Transfer Protocol version 1.1
          (HTTP/1.1) over TLS.";
       reference
         "RFC 9110: HTTP Semantics
          RFC 9112: HTTP/1.1";
     }

     identity http2 {
       base application-protocol;
       description
         "The identity for Hypertext Transfer Protocol version 2
          (HTTP/2).";

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       reference
         "RFC 9113: HTTP/2";
     }

     identity https2 {
       base application-protocol;
       description
         "The identity for Hypertext Transfer Protocol version 2
          (HTTP/2) over TLS.";
       reference
         "RFC 9113: HTTP/2";
     }

     identity ftp {
       base application-protocol;
       description
         "The identity for File Transfer Protocol.";
       reference
         "RFC 959: File Transfer Protocol (FTP)";
     }

     identity ssh {
       base application-protocol;
       description
         "The identity for Secure Shell (SSH) protocol.";
       reference
         "RFC 4250: The Secure Shell (SSH) Protocol";
     }

     identity telnet {
       base application-protocol;
       description
         "The identity for telnet.";
       reference
         "RFC 854: Telnet Protocol";
     }

     identity smtp {
       base application-protocol;
       description
         "The identity for Simple Mail Transfer Protocol.";
       reference
         "RFC 5321: Simple Mail Transfer Protocol (SMTP)";
     }

     identity pop3 {
       base application-protocol;
       description

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         "The identity for Post Office Protocol 3 (POP3).";
       reference
         "RFC 1939: Post Office Protocol - Version 3 (POP3)";
     }

     identity pop3s {
       base application-protocol;
       description
         "The identity for Post Office Protocol 3 (POP3) over TLS";
       reference
         "RFC 1939: Post Office Protocol - Version 3 (POP3)
          RFC 2595: Using TLS with IMAP, POP3 and ACAP";
     }

     identity imap {
       base application-protocol;
       description
         "The identity for Internet Message Access Protocol (IMAP).";
       reference
         "RFC 9051: Internet Message Access Protocol (IMAP) - Version
          4rev2";
     }

     identity imaps {
       base application-protocol;
       description
         "The identity for Internet Message Access Protocol (IMAP) over
          TLS";
       reference
         "RFC 9051: Internet Message Access Protocol (IMAP) - Version
          4rev2";
     }

     identity action {
       description
         "Base identity for action";
     }

     identity primary-action {
       base action;
       description
         "Base identity for primary action. Primary action is an action
          that handle the forwarding of the packets or flows in an
          NSF.";
     }

     identity secondary-action {
       base action;

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       description
         "Base identity for secondary action. Secondary action is an
          action in the background that does not affect the network,
          such as logging.";
     }

     identity ingress-action {
       base primary-action;
       description
         "Base identity for ingress action. The action to handle the
          network traffic that is entering the secured network.";
       reference
         "draft-ietf-i2nsf-capability-data-model-32:
          I2NSF Capability YANG Data Model - Ingress Action";
     }

     identity egress-action {
       base primary-action;
       description
         "Base identity for egress action. The action to handle the
          network traffic that is exiting the secured network.";
       reference
         "draft-ietf-i2nsf-capability-data-model-32:
          I2NSF Capability YANG Data Model - Egress Action";
     }

     identity pass {
       base ingress-action;
       base egress-action;
       description
         "The pass action allows traffic that matches
          the rule to proceed through the NSF to reach the
          destination.";
       reference
         "draft-ietf-i2nsf-capability-data-model-32:
          I2NSF Capability YANG Data Model - Actions and
          Default Action";
     }

     identity drop {
       base ingress-action;
       base egress-action;
       description
         "The drop action denies the traffic that
          matches the rule. The drop action should do a silent drop,
          which does not give any response to the source.";
       reference
         "draft-ietf-i2nsf-capability-data-model-32:

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          I2NSF Capability YANG Data Model - Actions and
          Default Action";
     }

     identity reject {
       base ingress-action;
       base egress-action;
       description
         "The reject action denies a packet to go through the NSF
          entering or exiting the internal network and sends a response
          back to the source. The response depends on the packet and
          implementation. For example, a TCP packet is rejected with
          TCP RST response or a UDP packet may be rejected with an
          ICMPv4 response message with Type 3 Code 3 or ICMPv6 response
          message Type 1 Code 4 (i.e., Destination Unreachable:
          Destination port unreachable).";
     }

     identity mirror {
       base ingress-action;
       base egress-action;
       description
         "The mirror action copies a packet and sends the packet's copy
          to the monitoring entity while still allowing the packet or
          flow to go through the NSF.";
       reference
         "draft-ietf-i2nsf-capability-data-model-32:
          I2NSF Capability YANG Data Model - Actions and
          Default Action";
     }

     identity rate-limit {
       base ingress-action;
       base egress-action;
       description
         "The rate limit action limits the number of packets or flows
          that can go through the NSF by dropping packets or flows
          (randomly or systematically). The drop mechanism, e.g., silent
          drop and unreachable drop (i.e., reject), is up to the
          implementation";
       reference
         "draft-ietf-i2nsf-capability-data-model-32:
          I2NSF Capability YANG Data Model - Actions and
          Default Action";
     }

     identity invoke-signaling {
       base egress-action;

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       description
         "The invoke-signaling action is used to convey information of
          the event triggering this action to a monitoring entity.";
     }

     identity tunnel-encapsulation {
       base egress-action;
       description
         "The tunnel encapsulation action is used to encapsulate the
          packet to be tunneled across the network to enable a secure
          connection.";
     }

     identity forwarding {
       base egress-action;
       description
         "The forwarding action is used to relay the packet from one
          network segment to another node in the network.";
     }

     identity transformation {
       base egress-action;
       description
         "The transformation action is used to transform a packet by
          modifying it (e.g., HTTP-to-CoAP packet translation).
          Note that a subset of transformation (e.g., HTTP-to-CoAP) is
          handled in this YANG module, rather than all the existing
          transformations.  Specific algorithmic transformations can be
          executed by a middlebox (e.g., NSF) for a given transformation
          name.";
       reference
         "RFC 8075: Guidelines for Mapping Implementations: HTTP to the
          Constrained Application Protocol (CoAP) - Translation between
          HTTP and CoAP.";
     }

     identity log-action {
       base secondary-action;
       description
         "Base identity for log action";
     }

     identity rule-log {
       base log-action;
       description
         "Log the policy rule that has been triggered by a packet or
          flow.";
     }

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     identity session-log {
       base log-action;
       description
         "A session is a connection (i.e., traffic flow) of a data plane
          that includes source and destination information of IP
          addresses and transport port numbers with the protocol used.
          Log the session that triggered a policy rule.";
     }

     identity icmp-message {
       description
         "Base identity for ICMP Message types. Note that this YANG
          module only provide ICMP messages that is shared between
          ICMPv4 and ICMPv6 (e.g., Destination Unreachable: Port
          Unreachable which is ICMPv4 type 3 code 3 or ICMPv6 type 1
          code 4).";
       reference
         "RFC  792: Internet Control Message Protocol
          RFC 8335: PROBE: A Utility for Probing Interfaces
          IANA: Internet Control Message Protocol (ICMP)
          Parameters
          IANA: Internet Control Message Protocol version 6
          (ICMPv6) Parameters";
     }

     identity echo-reply {
       base icmp-message;
       description
         "Identity for 'Echo Reply' ICMP message type 0 in ICMPv4 or
          type 129 in ICMPv6";
     }

     identity destination-unreachable {
       base icmp-message;
       description
         "Identity for 'Destination Unreachable' ICMP message type 3 in
          ICMPv4 or type 1 in ICMPv6";
     }

     identity redirect {
       base icmp-message;
       description
         "Identity for 'Redirect' ICMP message type 5 in ICMPv4
          or type 137 in ICMPv6";
     }

     identity echo {
       base icmp-message;

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       description
         "Identity for 'Echo' ICMP message type 8 in ICMPv4 or type 128
          in ICMPv6";
     }

     identity router-advertisement {
       base icmp-message;
       description
         "Identity for 'Router Advertisement' ICMP message type 9 in
          ICMPv4 or type 134 in ICMPv6";
     }

     identity router-solicitation {
       base icmp-message;
       description
         "Identity for 'Router Solicitation' ICMP message type 10 in
          ICMPv4 or type 135 in ICMPv6";
     }

     identity time-exceeded {
       base icmp-message;
       description
         "Identity for 'Time exceeded' ICMP message type 11 in ICMPv4
          or type 3 in ICMPv6";
     }

     identity parameter-problem {
       base icmp-message;
       description
         "Identity for 'Parameter Problem' ICMP message type 12 in
          ICMPv4 or type 4 in ICMPv6";
     }

     identity experimental-mobility-protocols {
       base icmp-message;
       description
         "Identity for 'Experimental Mobility Protocols' ICMP message
          type 41 in ICMPv4 or type 150 in ICMPv6";
     }

     identity extended-echo-request {
       base icmp-message;
       description
         "Identity for 'Extended Echo Request' ICMP message type 42
          in ICMPv4 or type 160 in ICMPv6";
     }

     identity extended-echo-reply {

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       base icmp-message;
       description
         "Identity for 'Extended Echo Reply' ICMP message type 43 in
          ICMPv4 or type 161 in ICMPv6";
     }

     identity port-unreachable {
       base destination-unreachable;
       description
         "Identity for port unreachable in destination unreachable
          message (i.e., ICMPv4 type 3 code 3 or ICMPv6 type 1 code 4)";
     }

     identity request-no-error {
       base extended-echo-request;
       description
         "Identity for request with no error in extended echo request
          message (i.e., ICMPv4 type 42 code 0 or ICMPv6 type 160
          code 0)";
     }

     identity reply-no-error {
       base extended-echo-reply;
       description
         "Identity for reply with no error in extended echo reply
          message (i.e., ICMPv4 type 43 code 0 or ICMPv6 type 161
          code 0)";
     }

     identity malformed-query {
       base extended-echo-reply;
       description
         "Identity for malformed query in extended echo reply message
          (i.e., ICMPv4 type 43 code 1 or ICMPv6 type 161 code 1)";
     }

     identity no-such-interface {
       base extended-echo-reply;
       description
         "Identity for no such interface in extended echo reply message
          (i.e., ICMPv4 type 43 code 2 or ICMPv6 type 161 code 2)";
     }

     identity no-such-table-entry {
       base extended-echo-reply;
       description
         "Identity for no such table entry in extended echo reply
          message (i.e., ICMPv4 type 43 code 3 or ICMPv6 type 161

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          code 3)";
     }

     identity multiple-interfaces-satisfy-query {
       base extended-echo-reply;
       description
         "Identity for multiple interfaces satisfy query in extended
          echo reply message (i.e., ICMPv4 type 43 code 4 or ICMPv6
          type 161 code 4) ";
       reference
         "RFC  792: Internet Control Message Protocol
          RFC 8335: PROBE: A Utility for Probing Interfaces";
     }

     identity ioc-format {
       description
         "This represents the base identity for the format of the
          Indicators of Compromise (IOC).";
     }

     identity stix {
       base ioc-format;
       description
         "This represents the Structured Threat Information Expression
          (STIX) format in JSON.";
       reference
         "STIX: Structured Threat Information Expression version 2.1 - JSON
          format";
     }

     identity misp {
       base ioc-format;
       description
         "This represents the Malware Information Sharing Platform (MISP)
          Core format.";
       reference
         "MISPCORE: Malware Information Sharing Platform (MISP) Core
          Format";
     }

     identity openioc {
       base ioc-format;
       description
         "This represents the OpenIOC format.";
       reference
         "OPENIOC: OpenIOC 1.1 Schema document";
     }

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     identity device-type {
       description
         "Base identity for types of device. This identity is used for
          type of the device for the source or destination of a packet
          or traffic flow.";
     }

     identity computer {
       base device-type;
       description
         "Identity for computer such as personal computer (PC)
          and server.";
     }

     identity mobile-phone {
       base device-type;
       description
         "Identity for mobile-phone such as smartphone and
          cellphone";
     }

     identity voip-vocn-phone {
       base device-type;
       description
         "Identity for VoIP (Voice over Internet Protocol) or VoCN
          (Voice over Cellular Network, such as Voice over LTE or 5G)
          phone";
     }

     identity tablet {
       base device-type;
       description
         "Identity for tablet devices";
     }

     identity network-infrastructure-device {
       base device-type;
       description
         "Identity for network infrastructure devices
          such as switch, router, and access point";
     }

     identity iot-device {
       base device-type;
       description
         "Identity for Internet of Things (IoT) devices
          such as sensors, actuators, and low-power
          low-capacity computing devices";

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     }

     identity ot {
       base device-type;
       description
         "Identity for Operational Technology (OT) devices (also
          known as industrial control systems) that interact
          with the physical environment and detect or cause direct
          change through the monitoring and control of devices,
          processes, and events such as programmable logic
          controllers (PLCs), digital oscilloscopes, building
          management systems (BMS), and fire control systems";
     }

     identity vehicle {
       base device-type;
       description
         "Identity for transportation vehicles that connect to and
          share data through the Internet over Vehicle-to-Everything
          (V2X) communications.";
     }

    /*
     * Typedefs
     */

     typedef time {
       type string {
         pattern '(0[0-9]|1[0-9]|2[0-3]):[0-5][0-9]:[0-5][0-9](\.\d+)?'
           + '(Z|[\+\-]((1[0-3]|0[0-9]):([0-5][0-9])|14:00))?';
       }
       description
         "The time type represents an instance of time of zero-duration
          in the specified timezone that recurs every day.";
     }

     typedef day {
       type enumeration {
         enum monday {
           description
             "This represents Monday.";
         }
         enum tuesday {
           description
             "This represents Tuesday.";
         }
         enum wednesday {
           description

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             "This represents Wednesday";
         }
         enum thursday {
           description
             "This represents Thursday.";
         }
         enum friday {
           description
             "This represents Friday.";
         }
         enum saturday {
           description
             "This represents Saturday.";
         }
         enum sunday {
           description
             "This represents Sunday.";
         }
       }
       description
         "The type for representing the day of the week.";
     }

    /*
     * Groupings
     */

     grouping ip-address-info {
       description
         "There are two types to configure a security policy
          for an IP address, such as IPv4 adress and IPv6 address.";
       choice match-type {
         description
           "User can choose between IPv4 and IPv6.";
         case range-match-ipv4 {
           list range-ipv4-address {
             key "start end";
             leaf start {
               type inet:ipv4-address-no-zone;
               mandatory true;
               description
                 "A start IPv4 address for a range match.";
             }
             leaf end {
               type inet:ipv4-address-no-zone;
               mandatory true;
               description
                 "An end IPv4 address for a range match.";

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             }
             description
               "A range match for IPv4 addresses is provided.
                Note that the start IPv4 address must be lower than
                the end IPv4 address.";
           }
         }
         case range-match-ipv6 {
           list range-ipv6-address {
             key "start end";
             leaf start {
               type inet:ipv6-address-no-zone;
               mandatory true;
               description
                 "A start IPv6 address for a range match.";
             }
             leaf end {
               type inet:ipv6-address-no-zone;
               mandatory true;
               description
                 "An end IPv6 address for a range match.";
             }
             description
               "A range match for IPv6 addresses is provided.
                Note that the start IPv6 address must be lower than
                the end IPv6 address.";
           }
         }
       }
     }

     grouping user-group {
       description
         "This group represents user group information to label MAC
          addresses and IP (IPv4 or IPv6) addresses as a group of users.";
       leaf name {
         type string;
         description
           "This represents the name of a user-group.  A user-group name
            is used to map a user-group's name (e.g., employees) to IP
            address(es), MAC address(es).
            It is dependent on implementation.";
       }
       leaf-list mac-address {
         type yang:mac-address;
         description
           "Represent the MAC Address of a user-group. A user-group
            can have multiple MAC Addresses.";

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       }
       uses ip-address-info{
         description
           "This represents the IP addresses of a user-group.";
         refine match-type{
           mandatory true;
         }
       }
     }

     grouping device-group {
       description
         "This group represents device group information to label
          IP (IPv4 or IPv6) addresses that provide services hosted
          on the application protocol.";
       leaf name {
         type string;
         description
           "This represents the name of a device-group.";
       }
       uses ip-address-info{
         description
           "This represents the IP addresses of a device-group.";
         refine match-type{
           mandatory true;
         }
       }
       leaf-list application-protocol {
         type identityref {
           base application-protocol;
         }
         description
           "This represents the application layer protocols of devices.
            If this is not set, it cannot support the appropriate
            protocol";
       }
     }

     grouping location-group {
       description
         "This group represents location-group information to map
          IPv4 or IPv6 address to the geographical location.";
       leaf country {
         type string {
           length "2";
           pattern "[a-zA-Z]{2}";
         }
         description

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           "This represents the 2-letter ISO country code conforming to
            ISO3166-1 alpha 2. Examples include 'US' for United States,
            'JP' for Japan, and 'PL' for Poland.";
         reference
           "RFC 8805: A Format for Self-Published IP Geolocation Feeds -
            Alpha2code
            ISO 3166-1: Decoding table alpha-2 country code";
       }
       leaf region {
         type string {
           length "5..6";
           pattern "[a-zA-Z]{2}-[a-zA-Z0-9]{2,3}";
         }
         description
           "This represents the ISO region code conforming to ISO 3166-2.
            Examples include 'ID-RI' for Riau province of Indonesia and
            'NG-RI' for the Rivers province in Nigeria.";
         reference
           "RFC 8805: A Format for Self-Published IP Geolocation Feeds -
            Region
            ISO 3166-2: 3166-2 subdivision code";
       }
       leaf city {
         type string;
         description
           "This represents the city of a region. Examples include
            'Dublin', 'New York', and 'Sao Paulo'.";
         reference
           "RFC 8805: A Format for Self-Published IP Geolocation Feeds -
            City";
       }
       uses ip-address-info{
         refine match-type{
           mandatory true;
           description
             "This represents the IP addresses of a location-group.";
         }
       }
       reference
         "RFC 8805: A Format for Self-Published IP Geolocation Feeds -
          An access control for a geographical location (i.e.,
          geolocation) that has the corresponding IP prefix.";
     }

     grouping payload-string {
       description
         "The grouping for payload-string content.  It contains
          information such as name and string content.";

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     }

     list i2nsf-cfi-policy {
       key "name";
       description
         "This is a security policy list.  Each policy in the list
          contains a list of security policy rules, and is a policy
          instance to have the information of where and when a policy
          needs to be applied.";
       leaf name {
         type string;
         description
           "The name which identifies the policy.";
       }
       leaf language {
         type string {
           pattern '((([A-Za-z]{2,3}(-[A-Za-z]{3}(-[A-Za-z]{3})'
                 + '{0,2})?)|[A-Za-z]{4}|[A-Za-z]{5,8})(-[A-Za-z]{4})?'
                 + '(-([A-Za-z]{2}|[0-9]{3}))?(-([A-Za-z0-9]{5,8}'
                 + '|([0-9][A-Za-z0-9]{3})))*(-[0-9A-WYZa-wyz]'
                 + '(-([A-Za-z0-9]{2,8}))+)*(-[Xx](-([A-Za-z0-9]'
                 + '{1,8}))+)?|[Xx](-([A-Za-z0-9]{1,8}))+|'
                 + '(([Ee][Nn]-[Gg][Bb]-[Oo][Ee][Dd]|[Ii]-'
                 + '[Aa][Mm][Ii]|[Ii]-[Bb][Nn][Nn]|[Ii]-'
                 + '[Dd][Ee][Ff][Aa][Uu][Ll][Tt]|[Ii]-'
                 + '[Ee][Nn][Oo][Cc][Hh][Ii][Aa][Nn]'
                 + '|[Ii]-[Hh][Aa][Kk]|'
                 + '[Ii]-[Kk][Ll][Ii][Nn][Gg][Oo][Nn]|'
                 + '[Ii]-[Ll][Uu][Xx]|[Ii]-[Mm][Ii][Nn][Gg][Oo]|'
                 + '[Ii]-[Nn][Aa][Vv][Aa][Jj][Oo]|[Ii]-[Pp][Ww][Nn]|'
                 + '[Ii]-[Tt][Aa][Oo]|[Ii]-[Tt][Aa][Yy]|'
                 + '[Ii]-[Tt][Ss][Uu]|[Ss][Gg][Nn]-[Bb][Ee]-[Ff][Rr]|'
                 + '[Ss][Gg][Nn]-[Bb][Ee]-[Nn][Ll]|[Ss][Gg][Nn]-'
                 + '[Cc][Hh]-[Dd][Ee])|([Aa][Rr][Tt]-'
                 + '[Ll][Oo][Jj][Bb][Aa][Nn]|[Cc][Ee][Ll]-'
                 + '[Gg][Aa][Uu][Ll][Ii][Ss][Hh]|'
                 + '[Nn][Oo]-[Bb][Oo][Kk]|[Nn][Oo]-'
                 + '[Nn][Yy][Nn]|[Zz][Hh]-[Gg][Uu][Oo][Yy][Uu]|'
                 + '[Zz][Hh]-[Hh][Aa][Kk][Kk][Aa]|[Zz][Hh]-'
                 + '[Mm][Ii][Nn]|[Zz][Hh]-[Mm][Ii][Nn]-'
                 + '[Nn][Aa][Nn]|[Zz][Hh]-[Xx][Ii][Aa][Nn][Gg])))';
         }
         default "en-US";
         description
           "The value in this field indicates the language tag
            used for all of the 'leaf description' described in the
            'i2nsf-cfi-policy'.

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            The attribute is encoded following the rules in Section 2.1
            in RFC 5646. The default language tag is 'en-US'";
         reference
           "RFC 5646: Tags for Identifying Languages";
       }
       leaf resolution-strategy {
         type identityref {
           base resolution-strategy;
         }
         default fmr;
         description
           "The resolution strategies that can be used to
            specify how to resolve conflicts that occur between
            actions of the same or different policy rules that
            are matched and contained in this particular NSF";

         reference
           "draft-ietf-i2nsf-capability-data-model-32:
            I2NSF Capability YANG Data Model - Resolution strategy";
       }
       list rules {
         key "name";

         description
           "There can be a single or multiple number of rules.";
         leaf name {
           type string;
           description
             "This represents the name for a rule. The name must be
              unique to represent different rules.";
         }

         leaf priority {
           type uint8 {
             range "1..255";
           }
           description
             "The priority keyword comes with a mandatory
              numeric value which can range from 1 through 255.
              Note that a higher number means a higher priority";
         }

         container event {
           description
             "This represents an event (i.e., a security event), for
              which a security rule is made.";
           leaf-list system-event {
             type identityref {

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               base system-event;
             }
             description
               "The security policy rule according to
                system events.";
           }

           leaf-list system-alarm {
             type identityref {
               base system-alarm;
             }
             description
               "The security policy rule according to
                system alarms.";
           }
         }

         container condition {
           description
           "Conditions for general security policies.";
           container firewall {
             description
               "A general firewall condition based on the packet
                header.";
             leaf-list source {
               type union {
                 type leafref {
                   path "/endpoint-groups/user-group/name";
                 }
                 type leafref {
                   path "/endpoint-groups/device-group/name";
                 }
               }
               description
               "This describes the path of the source.";
             }

             leaf-list destination {
               type union {
                 type leafref {
                   path "/endpoint-groups/user-group/name";
                 }
                 type leafref {
                   path "/endpoint-groups/device-group/name";
                 }
               }
               description
                 "This describes the path to the destinations.";

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             }

             leaf transport-layer-protocol {
               type identityref {
                 base transport-protocol;
               }
               description
                 "The transport-layer protocol to be matched.";
             }

             list range-port-number {
               key "start end";
               leaf start {
                 type inet:port-number;
                 description
                   "A start port number for a range match.";
               }
               leaf end {
                 type inet:port-number;
                 must '. >= ../start' {
                   error-message
                     "An end port number MUST be equal to or greater than
                      a start port number.";
                 }
                 description
                   "An end port number for a range match.";
               }
               description
                 "A range match for transport-layer port number. Note
                  that the start port number value must be lower than
                  the end port number value";
             }

             container icmp {
               description
                  "Represents the ICMPv4 and ICMPv6 packet header
                   information to determine if the set of policy
                   actions in this ECA policy rule should be executed
                   or not.";
                reference
                  "RFC  792: Internet Control Message Protocol
                   RFC 8335: PROBE: A Utility for Probing Interfaces";

               leaf-list message {
                 type identityref {
                   base icmp-message;
                 }
                 description

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                   "The security policy rule according to
                    ICMP message. The type is representing the
                    ICMP message corresponds to the ICMP type and
                    code.";
                 reference
                   "RFC  792: Internet Control Message Protocol
                    RFC 8335: PROBE: A Utility for Probing Interfaces
                    IANA: Internet Control Message Protocol (ICMP)
                    Parameters
                    IANA: Internet Control Message Protocol version 6
                    (ICMPv6) Parameters";
               }
             }
           }

           container ddos {
             description
               "A condition for a DDoS attack.";
             container rate-limit {
               description
                 "This describes the rate-limit.";
               leaf packet-rate-threshold {
                 type uint64;
                 units "pps";
                 description
                   "This is a trigger value for a rate limit of packet
                    rate in packets per second (pps) for a
                    DDoS-attack mitigation.";
               }
               leaf byte-rate-threshold {
                 type uint64;
                 units "Bps";
                 description
                   "This is a trigger value for a rate limit of byte
                    rate in bytes per second (Bps) for a DDoS-attack
                    mitigation.";
               }
               leaf flow-rate-threshold {
                 type uint64;
                 description
                   "This is a trigger value for a rate limit of flow
                    creating request rate (e.g., new TCP connection
                    establishment) in flows per second for a DDoS-attack
                    mitigation.";
               }
             }
           }

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           container anti-virus {
             description
              "A condition for anti-virus";

             leaf-list exception-files {
               type string;
               description
                 "The type or name of the files to be excluded by the
                  antivirus. This can be used to keep the known
                  harmless files. Absolute paths are filenames/paths
                  to be excluded and relative ones are interpreted as
                  globs. Note that the file names can be hash names
                  to specify malicious files to block.";
               reference
                 "GLOB: Linux Programmer's Manual - GLOB";
             }
           }

           container payload {
             description
               "A condition based on a packet's content.";
             leaf-list content {
               type leafref {
                 path "/threat-prevention/payload-content/name";
               }
               description
                 "This describes the paths to a packet content's";
             }
           }

           container url-category {
             description
               "Condition for url category";
             leaf url-name {
               type leafref {
                 path "/endpoint-groups/url-group/name";
               }
               description
                 "This is description for the condition of a URL's
                  category such as SNS sites, game sites, ecommerce
                  sites, company sites, and university sites.";
             }
           }

           container voice {
             description
               "For the VoIP/VoCN security system, a VoIP/
                VoCN security system can monitor each

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                VoIP/VoCN flow and manage VoIP/VoCN
                security rules controlled by a centralized
                server for VoIP/VoCN security service
                (called VoIP IPS). The VoIP/VoCN security
                system controls each switch for the
                VoIP/VoCN call flow management by
                manipulating the rules that can be added,
                deleted, or modified dynamically.
                Note that VoIP is Voice over Internet Protocol
                and VoCN is Voice over Cellular Network such as
                Voice over LTE or 5G";
             reference
               "RFC 3261: SIP: Session Initiation Protocol";

             leaf-list source-id {
               type leafref {
                 path "/endpoint-groups/voice-group/name";
               }
               description
                 "The security policy rule according to
                  the 'From' header field of the SIP.";
               reference
                 "RFC 3261: SIP: Session Initiation Protocol
                            - Section 8.1.1.3 (From)";
             }

             leaf-list destination-id {
               type leafref {
                 path "/endpoint-groups/voice-group/name";
               }
               description
                 "The security policy rule according to
                  the 'To' header field of the SIP.";
               reference
                 "RFC 3261: SIP: Session Initiation Protocol
                            - Section 8.1.1.2 (To)";
             }

             leaf-list user-agent {
               type string;
               description
                 "The security policy rule according to
                  the 'user-agent' field of the SIP.";
               reference
                 "RFC 3261: SIP: Session Initiation Protocol
                            - Section 20.41 (User-Agent)";
             }
           }

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           container context {
             description
               "Condition for matching the context of the packet, such
                as geographic location, time, packet direction";
             container time {
               description
                 "The time when a security policy rule should be
                  applied.";
               leaf start-date-time {
                 type yang:date-and-time;
                 description
                   "This is the start date and time for a security
                    policy rule.";
               }
               leaf end-date-time {
                 type yang:date-and-time;
                 description
                   "This is the end date and time for a security policy
                    rule.  The policy rule will stop working after the
                    specified end date and time.";
               }
               container period {
                 when
                   "../frequency!='only-once'";
                 description
                   "This represents the repetition time.  In the case
                    where the frequency is weekly, the days can be
                    set.";
                 leaf start-time {
                   type time;
                   description
                     "This is a period's start time for an event.";
                 }
                 leaf end-time {
                   type time;
                   description
                     "This is a period's end time for an event.";
                 }
                 leaf-list day {
                   when
                     "../../frequency='weekly'";
                   type day;
                   min-elements 1;
                   description
                     "This represents the repeated day of every week
                     (e.g., Monday and Tuesday).  More than one day can
                     be specified.";
                 }

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                 leaf-list date {
                   when
                     "../../frequency='monthly'";
                   type int8 {
                     range "1..31";
                   }
                   min-elements 1;
                   description
                     "This represents the repeated date of every month.
                      More than one date can be specified.";
                 }
                 leaf-list month {
                   when
                     "../../frequency='yearly'";
                   type string{
                     pattern '\d{2}-\d{2}';
                   }
                   min-elements 1;
                   description
                     "This represents the repeated date and month of
                      every year.  More than one can be specified.
                      A pattern used here is Month and Date (MM-DD).";
                 }
               }

               leaf frequency {
                 type enumeration {
                   enum only-once {
                     description
                       "This represents that the rule is immediately
                        enforced only once and not repeated. The policy
                        will continuously be active from the
                        start-date-time to the end-date-time.";
                   }
                   enum daily {
                     description
                       "This represents that the rule is enforced on a
                        daily basis. The policy will be repeated daily
                        until the end-date-time.";
                   }
                   enum weekly {
                     description
                       "This represents that the rule is enforced on a
                        weekly basis. The policy will be repeated weekly
                        until the end-date-time. The repeated days can
                        be specified.";
                   }
                   enum monthly {

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                     description
                       "This represents that the rule is enforced on a
                        monthly basis. The policy will be repeated
                        monthly until the end-date-time.";
                   }
                   enum yearly {
                     description
                       "This represents that the rule is enforced on a
                        yearly basis.  The policy will be repeated
                        yearly until the end-date-time.";
                   }
                 }
                 default only-once;
                 description
                   "This represents how frequently the rule should be
                    enforced.";
               }
             }

             container application {
               description
                 "Condition for application";
               leaf-list protocol {
                 type identityref {
                   base application-protocol;
                 }
                 description
                   "The condition based on the application layer
                    protocol";
               }
             }

             container device-type {
               description
                 "Condition for type of the destination device";
               leaf-list device {
                 type identityref {
                   base device-type;
                 }
                 description
                   "The device attribute that can identify a device (i.e.,
                    computer, mobile phone, smartphone, VoIP/VoCN phone,
                    tablet, network infrastructure device, IoT device,
                    OT device, and vehicle).";
               }
             }

             container users {

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               description
                 "Condition for users";
               list user {
                 key "id";
                 description
                   "The user with which the traffic flow is associated
                    can be identified by either a user ID or username.
                    The user-to-IP address mapping is assumed to be
                    provided by the unified user management system via
                    network.";
                 leaf id {
                   type uint32;
                   description
                     "The ID of the user.";
                 }
                 leaf name {
                   type string;
                   description
                     "The name of the user.";
                 }
               }
               list group {
                 key "id";
                 description
                   "The user group with which the traffic flow is
                    associated can be identified by either a group ID
                    or group name. The group-to-IP address and
                    user-to-group mappings are assumed to be provided by
                    the unified user management system via network.";
                 leaf id {
                   type uint32;
                   description
                     "The ID of the group.";
                 }
                 leaf name {
                   type string;
                   description
                     "The name of the group.";
                 }
               }
             }

             container geographic-location {
               description
                 "A condition for a location-based connection";
               container source {
                 leaf country {
                   type leafref {

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                     path "/endpoint-groups/location-group/country";
                   }
                   description
                     "The name of the country in the 2-letter ISO country
                      code conforming to ISO3166-1 alpha-2.";
                   reference
                     "ISO 3166-1: Decoding table alpha-2 country code";
                 }
                 leaf region {
                   type leafref {
                     path "/endpoint-groups/location-group/region";
                   }
                   description
                     "The region code conforming to ISO 3166-2.";
                   reference
                     "ISO 3166-2: 3166-2 subdivision code.";
                 }
                 leaf city {
                   type leafref {
                     path "/endpoint-groups/location-group/city";
                   }
                   description
                     "The name of the city of the location.";
                 }
                 description
                   "This describes the paths to a location's source.
                    The values in this field will be mapped into
                    either IPv4 or IPv6 addresses defined in
                    /endpoint-groups/location-group.";
               }
               container destination {
                 leaf country {
                   type leafref {
                     path "/endpoint-groups/location-group/country";
                   }
                   description
                     "The name of the country in the 2-letter ISO country
                      code conforming to ISO3166-1 alpha-2.";
                   reference
                     "ISO 3166-1: Decoding table alpha-2 country code";
                 }
                 leaf region {
                   type leafref {
                     path "/endpoint-groups/location-group/region";
                   }
                   description
                     "The region code conforming to ISO 3166-2.";
                   reference

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                     "ISO 3166-2: 3166-2 subdivision code.";
                 }
                 leaf city {
                   type leafref {
                     path "/endpoint-groups/location-group/city";
                   }
                   description
                     "The name of the city of the location.";
                 }
                 description
                   "This describes the paths to a location's
                    destination. The values in this field will be
                    mapped into either IPv4 or IPv6 addresses defined in
                    /endpoint-groups/location-group.";
               }
             }
           }

           container threat-feed {
             description
               "A condition based on the threat-feed information.";
             leaf-list name {
               type leafref {
                 path "/threat-prevention/threat-feed-list/name";
               }
               description
                 "This describes the paths to a threat-feed's sources.";
             }
           }
         }

         container action {
           description
             "This is the action container.";
           container primary-action {
             description
               "This represents primary actions (e.g., ingress and
                egress actions) to be applied to a condition.
                If this is not set, it cannot support the primary
                actions.";
             leaf action {
               type identityref {
                 base primary-action;
               }
               mandatory true;
               description
                 "Ingress actions: pass, drop, reject, rate-limit,
                  and mirror.

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                  Egress actions: pass, drop, reject, rate-limit,
                  mirror, invoke-signaling, tunnel-encapsulation,
                  forwarding, and transformation.";
             }
             leaf limit {
               when "../action = 'i2nsfcfi:rate-limit'" {
                 description
                   "Rate-limit is valid only when rate-limit action is
                    used.";
               }
               type decimal64 {
                 fraction-digits 2;
               }
               units "bytes per second";
               description
                 "Specifies how to rate-limit the traffic.";
             }
           }
           container secondary-action {
             description
               "This represents secondary actions (e.g., log and syslog)
                to be applied if they are needed.  If this is not set,
                it cannot support the secondary actions.";
             leaf log-action {
               type identityref {
                 base secondary-action;
               }
               description
                 "Log action: rule log and session log";
             }
           }
         }
       }
     }

     container endpoint-groups {
       description
         "A logical entity in a business environment, where a security
          policy is to be applied.";
       list user-group{
         uses user-group;
         key "name";
         description
           "This represents a user group.";
       }
       list device-group {
         key "name";
         uses device-group;

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         description
           "This represents a device group.";
       }
       list location-group{
         key "country region city";
         uses location-group;
         description
           "This represents a location group.";
       }
       list url-group {
         key "name";
         description
           "This describes the list of URL.";
         leaf name {
           type string;
           description
             "This is the name of URL group, e.g., SNS sites,
              gaming sites, ecommerce sites";
         }
         leaf-list url {
           type inet:uri;
           description
             "Specifies the URL to be added into the group.";
           reference
             "RFC 3986: Uniform Resource Identifier (URI): Generic
              Syntax";
         }
       }
       list voice-group {
         key "name";
         description
           "This describes the list of Voice ID";
         leaf name {
           type string;
           description
             "This is the name of the voice group.";
         }
         leaf-list sip-id {
           type inet:uri;
           description
             "Specifies the logical identity of the SIP user written in
              SIP URI scheme.";
           reference
             "RFC3261: SIP: Session Initiation Protocol
                       - Section 19.1.1 (SIP and SIPS URI Components)";
         }
       }
     }

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     container threat-prevention {
       description
         "The container for threat-prevention.";
       list threat-feed-list {
         key "name";
         description
           "There can be a single or multiple number of
            threat-feeds.";
         leaf name {
           type string;
           description
             "This represents the name of the threat-feed.";
         }
         leaf-list ioc {
           type string;
           description
             "This field represents the Indicators of Compromise (IOC),
              i.e., the critical information of patterns or characteristics
              (signatures) in the threat feed that identifies malicious
              activities. The format of the information given in this field
              should be parsed based on the format field (e.g., STIX, MISP,
              and OpenIOC).";
         }
         leaf format {
           type identityref {
             base ioc-format;
           }
           mandatory true;
           description
             "This represents the format of the IOC information. This
              field is mandatory to parse the IOC. The examples of the
              format are STIX, MISP, OpenIOC.";
           reference
             "STIX: Structured Threat Information Expression version 2.1
              MISPCORE: Malware Information Sharing Platform (MISP) Core
              Format
              OPENIOC: OpenIOC 1.1 Schema document";
         }
       }

       list payload-content {
         key "name";
         leaf name {
           type string;
           description
             "This represents the name of a packet's payload-content.
              It should give an idea of why a specific payload content
              is marked as a threat.  For example, the name 'backdoor'

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              indicates the payload content is related to a backdoor
              attack.";
         }
         leaf description {
           type string;
           description
             "This represents the description of a payload. Describe
              how the payload contents are related to a security
              attack.";
         }
         list contents {
           key "content";
           ordered-by user;
           leaf content {
             type binary;
             description
               "This represents the pattern of the payload contents (i.e.,
                the data after a transport layer header) to be matched.
                Due to the types of threats, the type of the content is
                defined as a binary to accommodate any kind of a payload
                type such as HTTP, HTTPS, and SIP.

                If multiple instances of content are defined, it should
                match all contents somewhere in the session stream. The
                content pattern should be matched based on the order
                given by the user. The scope of the payload to be matched
                can be defined by the depth and offset/distance fields.";
           }
           leaf depth {
             type uint16 {
               range "1..max";
             }
             units "bytes";
             description
               "The field specifies how far a packet should be searched
                for the specified content pattern defined in the content
                field. For example, a depth of 5 means to only look for
                the specified content pattern within the first 5 bytes
                of the payload. This field accept values greater than or
                equal to the content length being searched. If this
                field is undefined, then the content pattern should be
                searched within the whole payload.";
           }
           choice starting-point {
             description
               "Choice of how to specify the starting point of matching
                the pattern to the payload. If this field is undefined,
                then the content pattern should be searched from the

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                beginning of the payload.";
             case offset {
               leaf offset {
                 type int32 {
                   range "0..65535";
                 }
                 units "bytes";
                 description
                   "The field specifies where to start searching for the
                    specified content pattern within the payload.
                    For example, an offset of 5 means to start looking for
                    the specified content pattern after the first 5 bytes
                    of the payload.";
               }
             }
             case distance {
               leaf distance {
                 type int32 {
                   range "0..65535";
                 }
                 units "bytes";
                 description
                   "The field specifies how far a payload should be
                    ignored before starting to search for the specified
                    content pattern relative to the end of the previous
                    specified content pattern match. This can be thought
                    of as exactly the same thing as offset, except it is
                    relative to the end of the last pattern match instead
                    of the beginning of the packet. For example, a distance
                    of 5 means to start looking for the specified content
                    pattern 5 bytes after the last byte of the matched
                    pattern.

                    Note that this field cannot be used if the content is
                    the first order of the list.";
               }
             }
           }
           description
             "List of contents and their scopes for matching content
              pattern with the payload";
         }
         description
           "This represents a payload-string group.";
       }
     }
   }
   <CODE ENDS>

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               Figure 18: YANG for Consumer-Facing Interface

7.  XML Configuration Examples of High-Level Security Policy Rules

   This section shows XML configuration examples of high-level security
   policy rules that are delivered from the I2NSF User to the Security
   Controller over the Consumer-Facing Interface.  The considered
   examples are: Database registration, time-based firewall for web
   filtering, VoIP/VoCN security service, and DDoS-attack mitigation.

7.1.  Database Registration: Information of Positions and Devices
      (Endpoint Group)

   The endpoint-group is used to register known network nodes and label
   them into a higher-level name (i.e., human recognizable language).
   If new endpoints are introduced to the network, it is necessary to
   first register their data to the database.  For example, if new
   members are newly introduced in different groups (i.e., user-group,
   device-group, url-group, and voice-group), each of them should be
   registered as separate entities with their corresponding information.

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  <?xml version="1.0" encoding="UTF-8" ?>
  <endpoint-groups
   xmlns="urn:ietf:params:xml:ns:yang:ietf-i2nsf-cons-facing-interface">
    <user-group>
      <name>employees</name>
      <range-ipv4-address>
        <start>192.0.2.11</start>
        <end>192.0.2.90</end>
      </range-ipv4-address>
    </user-group>
    <device-group>
      <name>webservers</name>
      <range-ipv4-address>
        <start>198.51.100.11</start>
        <end>198.51.100.20</end>
      </range-ipv4-address>
      <application-protocol>http</application-protocol>
      <application-protocol>https</application-protocol>
    </device-group>
    <url-group>
      <name>sns-websites</name>
      <url>https://www.sns-example1.com/</url>
      <url>https://www.sns-example2.com/</url>
    </url-group>
    <voice-group>
      <name>malicious-id</name>
      <sip-id>sip:alice@atlanta.com</sip-id>
      <sip-id>sip:bob@203.0.113.15</sip-id>
      <sip-id>sip:carol@chicago.com</sip-id>
    </voice-group>
  </endpoint-groups>

     Figure 19: Registering User-group, Device-group, Voice-group in
                IPv4 Addresses, and URL-group Information

   Figure 19 shows an example XML representation of the registered
   information for the user-group, device-group, voice-group in IPv4
   address [RFC5737], and url-group.

   1.  The IPv4 addresses from 192.0.2.11 to 192.0.2.90 are labeled as a
       group of users called "employees".

   2.  The IPv4 addresses from 198.51.100.11 to 198.51.100.20 provide
       services with HTTP and HTTPS application protocol labeled as
       "webservers".

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   3.  The "https://www.sns-example1.com/" and "https://www.sns-
       example2.com/" URLs are labeled as "sns-websites".

   4.  The "sip:alice@atlanta.com", "sip:bob@203.0.113.15", and
       "sip:carol@chicago.com" SIP identities are labeled as "malicious-
       id".

  <?xml version="1.0" encoding="UTF-8" ?>
  <endpoint-groups
   xmlns="urn:ietf:params:xml:ns:yang:ietf-i2nsf-cons-facing-interface">
    <user-group>
      <name>employees-v6</name>
      <range-ipv6-address>
        <start>2001:db8:0:1::11</start>
        <end>2001:db8:0:1::90</end>
      </range-ipv6-address>
    </user-group>
    <device-group>
      <name>webservers-v6</name>
      <range-ipv6-address>
        <start>2001:db8:0:2::11</start>
        <end>2001:db8:0:2::20</end>
      </range-ipv6-address>
      <application-protocol>http</application-protocol>
      <application-protocol>https</application-protocol>
    </device-group>
    <voice-group>
      <name>malicious-id-v6</name>
      <sip-id>sip:david@[2001:db8:2ef0::32b7]</sip-id>
    </voice-group>
  </endpoint-groups>

       Figure 20: Registering User-group, Device-group, Voice-group
                      Information in IPv6 Addresses

   Also, Figure 20 shows an example XML representation of the registered
   information for the user-group, device-group, and voice-group in IPv6
   addresses [RFC3849].

   1.  The IPv6 addresses from 2001:db8:0:1::11 to 2001:db8:0:1::90 are
       labeled as a group of users called "employees-v6".

   2.  The IPv6 addresses from 2001:db8:0:2::11 to 2001:db8:0:2::20
       provide services with HTTP and HTTPS application protocol labeled
       as "webservers-v6".

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   3.  The "sip:david@[2001:db8:2ef0::32b7]" SIP identity is labeled as
       "malicious-id-v6".

7.2.  Scenario 1: Block SNS Access during Business Hours

   The first example scenario is to "block SNS access during office
   hours" using a time-based firewall policy.  In this scenario, all
   users registered as "employees" in the user-group list are unable to
   access Social Networking Services (SNS) during the office hours
   (weekdays).  The XML instance is described below:

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  <?xml version="1.0" encoding="UTF-8" ?>
  <i2nsf-cfi-policy
   xmlns="urn:ietf:params:xml:ns:yang:ietf-i2nsf-cons-facing-interface">
    <name>security_policy_for_blocking_sns</name>
    <rules>
      <name>block_access_to_sns_during_office_hours</name>
      <condition>
        <firewall>
          <source>employees</source>
        </firewall>
        <url-category>
          <url-name>sns-websites</url-name>
        </url-category>
        <context>
          <time>
            <start-date-time>2021-03-11T09:00:00.00Z</start-date-time>
            <end-date-time>2021-12-31T18:00:00.00Z</end-date-time>
            <period>
              <start-time>09:00:00Z</start-time>
              <end-time>18:00:00Z</end-time>
              <day>monday</day>
              <day>tuesday</day>
              <day>wednesday</day>
              <day>thursday</day>
              <day>friday</day>
            </period>
            <frequency>weekly</frequency>
          </time>
        </context>
      </condition>
      <action>
        <primary-action>
          <action>drop</action>
        </primary-action>
      </action>
    </rules>
  </i2nsf-cfi-policy>

            Figure 21: An XML Example for Time-based Firewall

   Time-based-condition Firewall

   1.  The policy name is "security_policy_for_blocking_sns".

   2.  The rule name is "block_access_to_sns_during_office_hours".

   3.  The Source is "employees".

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   4.  The destination target is "sns-websites". "sns-websites" is the
       key which represents the list containing the information, such as
       URL, about sns-websites.

   5.  The action required is to "drop" any attempt to connect to
       websites related to Social networking.

7.3.  Scenario 2: Block Malicious VoIP/VoCN Packets Coming to a Company

   The second example scenario is to "block malicious VoIP/VoCN packets
   coming to a company" using a VoIP policy.  In this scenario, the
   calls coming from VOIP and/or VoCN sources with VoCN IDs that are
   classified as malicious are dropped.  The IP addresses of the
   employees and malicious VOIP IDs should be blocked are stored in the
   database or datastore of the enterprise.  Here and the rest of the
   cases assume that the security administrators or someone responsible
   for the existing and newly generated policies, are not aware of which
   and/or how many NSFs are needed to meet the security requirements.
   Figure 22 represents the XML document generated from YANG discussed
   in previous sections.  Once a high-level security policy is created
   by a security admin, it is delivered by the Consumer-Facing
   Interface, through RESTCONF server, to the security controller.  The
   XML instance is described below:

  <?xml version="1.0" encoding="UTF-8" ?>
  <i2nsf-cfi-policy
   xmlns="urn:ietf:params:xml:ns:yang:ietf-i2nsf-cons-facing-interface">
    <name>
      security_policy_for_blocking_malicious_voip_packets
    </name>
    <rules>
      <name>Block_malicious_voip_and_vocn_packets</name>
      <condition>
        <voice>
          <source-id>malicious-id</source-id>
        </voice>
        <firewall>
          <destination>employees</destination>
        </firewall>
      </condition>
      <action>
        <primary-action>
          <action>drop</action>
        </primary-action>
      </action>
    </rules>
  </i2nsf-cfi-policy>

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           Figure 22: An XML Example for VoIP Security Service

   Custom-condition Firewall

   1.  The policy name is
       "security_policy_for_blocking_malicious_voip_packets".

   2.  The rule name is "Block_malicious_voip_and_vocn_packets".

   3.  The source is "malicious-id".  The "malicious-id" is the key, so
       that it maps to the SIP identities that are named as "malicious-
       id".  This can be a single SIP identity or a list of SIP
       identities.

   4.  The destination target is "employees". "employees" is the key
       which represents the list containing information about employees,
       such as IP addresses.

   5.  The action required is "drop" when any incoming SIP packets are
       coming from "malicious-id" and targeting "employees".

7.4.  Scenario 3: Mitigate Flood Attacks on a Company Web Server

   The third example scenario is to "Mitigate flood attacks on a company
   web server" using a DDoS-attack mitigation policy.  Here, the time
   information is not set because the service provided by the network
   should be maintained at all times.  If the packets sent by any
   sources that target "webservers" are more than the set threshold,
   then the admin can set the percentage of the packets to be dropped to
   safely maintain the service.  Once the rule is set and delivered and
   enforced to the NSFs by the security controller, the NSFs will
   monitor the incoming packet amounts to act according to the rule set.
   The XML instance is described below:

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 <?xml version="1.0" encoding="UTF-8" ?>
 <i2nsf-cfi-policy
   xmlns="urn:ietf:params:xml:ns:yang:ietf-i2nsf-cons-facing-interface">
   <name>security_policy_for_ddos_attacks</name>
   <rules>
     <name>1000_packets_per_second</name>
     <condition>
       <firewall>
         <destination>webservers</destination>
       </firewall>
       <ddos>
         <rate-limit>
           <packet-rate-threshold>1000</packet-rate-threshold>
         </rate-limit>
       </ddos>
     </condition>
     <action>
       <primary-action>
         <action>drop</action>
       </primary-action>
     </action>
   </rules>
 </i2nsf-cfi-policy>

          Figure 23: An XML Example for DDoS-attack Mitigation

   DDoS-condition Firewall

   1.  The policy name is "security_policy_for_ddos_attacks".

   2.  The rule name is "1000_packets_per_second".

   3.  The destination is webservers.

   4.  The rate limit exists to limit the incoming amount of packets per
       second.  In this case the rate limit is "1000" packets per
       second.  This amount depends on the packet receiving capacity of
       the server devices.

   5.  The Source is all sources which send abnormal amount of packets.
       It is assumed that there is a counter per source IP address in
       this DDoS-condition Firewall.  The rate of "1000" packets per
       second is set for each source to send packets toward the
       destinations as webservers.

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   6.  The action required is to "drop" when the packet reception is
       more than "1000" packets per second for each source that sends
       packets to the destinations.

   Note that tcpdump can be used to capture packets per host as source
   [tcpdump]. tcpdump can limit capture to only packets related to a
   specific host (e.g., source) by using the host filter.

8.  IANA Considerations

   This document requests IANA to register the following URI in the
   "IETF XML Registry" [RFC3688]:

   URI: urn:ietf:params:xml:ns:yang:ietf-i2nsf-cons-facing-interface
   Registrant Contact: The IESG.
   XML: N/A; the requested URI is an XML namespace.

   This document requests IANA to register the following YANG module in
   the "YANG Module Names" registry [RFC7950][RFC8525]:

 name: ietf-i2nsf-cons-facing-interface
 namespace: urn:ietf:params:xml:ns:yang:ietf-i2nsf-cons-facing-interface
 prefix: i2nsfcfi
 reference: RFC XXXX

 // RFC Ed.: replace XXXX with an actual RFC number and remove
 // this note.

9.  Security Considerations

   The YANG module specified in this document defines a data schema
   designed to be accessed through network management protocols such as
   NETCONF [RFC6241] or RESTCONF [RFC8040].  The lowest NETCONF layer is
   the secure transport layer, and the required secure transport is
   Secure Shell (SSH) [RFC6242].  The lowest RESTCONF layer is HTTPS,
   and the required secure transport is TLS [RFC8446].

   The Network Configuration Access Control Model (NACM) [RFC8341]
   provides a means of restricting access to specific NETCONF or
   RESTCONF users to a preconfigured subset of all available NETCONF or
   RESTCONF protocol operations and contents.  Thus, NACM SHOULD be used
   to restrict the NSF registration from unauthorized users.

   There are a number of data nodes defined in this YANG module that are
   writable, creatable, and deletable (i.e., config true, which is the
   default).  These data nodes may be considered sensitive or vulnerable

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   in some network environments.  Write operations to these data nodes
   could have a negative effect on network and security operations.
   These data nodes have the following sensitivity/vulnerability:

   *  list i2nsf-cfi-policy: Writing to almost any element of this YANG
      module would directly impact the configuration of NSFs
      implementing the security policy, e.g., completely turning off
      security monitoring and mitigation capabilities; altering the
      scope of this monitoring and mitigation; creating an overwhelming
      logging volume to overwhelm downstream analytics or storage
      capacity; creating logging patterns which are confusing; or
      reducing the efficacy of statistics or artificial models built on
      historical data.

   *  container endpoint-groups: Writing to any element in this
      container can alter the configuration of the security services and
      may cause vulnerabilities in the network, e.g., changing
      registered malicious endpoints can remove the defense against
      known hostile clients.  The information given may also be
      considered private, hence it is strongly encouraged to inform
      affected users/customers of this fact and of the potential
      privacy-related consequences and trade-offs.

   *  container threat-prevention: Writing to any element in this
      container can alter the configuration of the security services and
      may cause vulnerabilities in the network, e.g., changing
      registered signature can let malicious content to get across the
      secured network without detection.

   Some of the readable data nodes in this YANG module may be considered
   sensitive or vulnerable in some network environments.  It is thus
   important to control read access (e.g., via get, get-config, or
   notification) to these data nodes.  These are the subtrees and data
   nodes with their sensitivity/vulnerability:

   *  list i2nsf-cfi-policy: The leak of this node to an attacker could
      reveal the specific configuration of security controls to an
      attacker.  An attacker can craft an attack path that avoids
      observation or mitigations; one may reveal topology information to
      inform additional targets or enable lateral movement; one enables
      the construction of an attack path that avoids observation or
      mitigations; one provides an indication that the operator has
      discovered the attack.

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   *  container endpoint-groups: This node holds a list of endpoint data
      that may be considered private to the users.  Disclosure of this
      information may expose sensitive details which can be used to
      define the identity and geographical location of a user.
      Malicious actors can leverage this information to threaten the
      user with cyber threat, e.g., voice phishing, or physical threat.

   *  container threat-prevention: The leak of this node to an attacker
      could reveal the specific detection system to an attacker.  An
      attacker can use this information to design new unknown attack
      strategies to circumvent the existing detection or prevention
      system.

10.  References

10.1.  Normative References

   [RFC0768]  Postel, J., "User Datagram Protocol", STD 6, RFC 768,
              DOI 10.17487/RFC0768, August 1980,
              <https://www.rfc-editor.org/info/rfc768>.

   [RFC0792]  Postel, J., "Internet Control Message Protocol", STD 5,
              RFC 792, DOI 10.17487/RFC0792, September 1981,
              <https://www.rfc-editor.org/info/rfc792>.

   [RFC0854]  Postel, J. and J. Reynolds, "Telnet Protocol
              Specification", STD 8, RFC 854, DOI 10.17487/RFC0854, May
              1983, <https://www.rfc-editor.org/info/rfc854>.

   [RFC0959]  Postel, J. and J. Reynolds, "File Transfer Protocol",
              STD 9, RFC 959, DOI 10.17487/RFC0959, October 1985,
              <https://www.rfc-editor.org/info/rfc959>.

   [RFC1939]  Myers, J. and M. Rose, "Post Office Protocol - Version 3",
              STD 53, RFC 1939, DOI 10.17487/RFC1939, May 1996,
              <https://www.rfc-editor.org/info/rfc1939>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC2595]  Newman, C., "Using TLS with IMAP, POP3 and ACAP",
              RFC 2595, DOI 10.17487/RFC2595, June 1999,
              <https://www.rfc-editor.org/info/rfc2595>.

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   [RFC3261]  Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
              A., Peterson, J., Sparks, R., Handley, M., and E.
              Schooler, "SIP: Session Initiation Protocol", RFC 3261,
              DOI 10.17487/RFC3261, June 2002,
              <https://www.rfc-editor.org/info/rfc3261>.

   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              DOI 10.17487/RFC3688, January 2004,
              <https://www.rfc-editor.org/info/rfc3688>.

   [RFC3986]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
              Resource Identifier (URI): Generic Syntax", STD 66,
              RFC 3986, DOI 10.17487/RFC3986, January 2005,
              <https://www.rfc-editor.org/info/rfc3986>.

   [RFC4250]  Lehtinen, S. and C. Lonvick, Ed., "The Secure Shell (SSH)
              Protocol Assigned Numbers", RFC 4250,
              DOI 10.17487/RFC4250, January 2006,
              <https://www.rfc-editor.org/info/rfc4250>.

   [RFC4340]  Kohler, E., Handley, M., and S. Floyd, "Datagram
              Congestion Control Protocol (DCCP)", RFC 4340,
              DOI 10.17487/RFC4340, March 2006,
              <https://www.rfc-editor.org/info/rfc4340>.

   [RFC4443]  Conta, A., Deering, S., and M. Gupta, Ed., "Internet
              Control Message Protocol (ICMPv6) for the Internet
              Protocol Version 6 (IPv6) Specification", STD 89,
              RFC 4443, DOI 10.17487/RFC4443, March 2006,
              <https://www.rfc-editor.org/info/rfc4443>.

   [RFC5321]  Klensin, J., "Simple Mail Transfer Protocol", RFC 5321,
              DOI 10.17487/RFC5321, October 2008,
              <https://www.rfc-editor.org/info/rfc5321>.

   [RFC5646]  Phillips, A., Ed. and M. Davis, Ed., "Tags for Identifying
              Languages", BCP 47, RFC 5646, DOI 10.17487/RFC5646,
              September 2009, <https://www.rfc-editor.org/info/rfc5646>.

   [RFC6241]  Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
              and A. Bierman, Ed., "Network Configuration Protocol
              (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
              <https://www.rfc-editor.org/info/rfc6241>.

   [RFC6242]  Wasserman, M., "Using the NETCONF Protocol over Secure
              Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011,
              <https://www.rfc-editor.org/info/rfc6242>.

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   [RFC6991]  Schoenwaelder, J., Ed., "Common YANG Data Types",
              RFC 6991, DOI 10.17487/RFC6991, July 2013,
              <https://www.rfc-editor.org/info/rfc6991>.

   [RFC7950]  Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
              RFC 7950, DOI 10.17487/RFC7950, August 2016,
              <https://www.rfc-editor.org/info/rfc7950>.

   [RFC8040]  Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
              Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
              <https://www.rfc-editor.org/info/rfc8040>.

   [RFC8075]  Castellani, A., Loreto, S., Rahman, A., Fossati, T., and
              E. Dijk, "Guidelines for Mapping Implementations: HTTP to
              the Constrained Application Protocol (CoAP)", RFC 8075,
              DOI 10.17487/RFC8075, February 2017,
              <https://www.rfc-editor.org/info/rfc8075>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC8335]  Bonica, R., Thomas, R., Linkova, J., Lenart, C., and M.
              Boucadair, "PROBE: A Utility for Probing Interfaces",
              RFC 8335, DOI 10.17487/RFC8335, February 2018,
              <https://www.rfc-editor.org/info/rfc8335>.

   [RFC8340]  Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
              BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
              <https://www.rfc-editor.org/info/rfc8340>.

   [RFC8341]  Bierman, A. and M. Bjorklund, "Network Configuration
              Access Control Model", STD 91, RFC 8341,
              DOI 10.17487/RFC8341, March 2018,
              <https://www.rfc-editor.org/info/rfc8341>.

   [RFC8342]  Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
              and R. Wilton, "Network Management Datastore Architecture
              (NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018,
              <https://www.rfc-editor.org/info/rfc8342>.

   [RFC8407]  Bierman, A., "Guidelines for Authors and Reviewers of
              Documents Containing YANG Data Models", BCP 216, RFC 8407,
              DOI 10.17487/RFC8407, October 2018,
              <https://www.rfc-editor.org/info/rfc8407>.

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   [RFC8446]  Rescorla, E., "The Transport Layer Security (TLS) Protocol
              Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
              <https://www.rfc-editor.org/info/rfc8446>.

   [RFC8525]  Bierman, A., Bjorklund, M., Schoenwaelder, J., Watsen, K.,
              and R. Wilton, "YANG Library", RFC 8525,
              DOI 10.17487/RFC8525, March 2019,
              <https://www.rfc-editor.org/info/rfc8525>.

   [RFC8805]  Kline, E., Duleba, K., Szamonek, Z., Moser, S., and W.
              Kumari, "A Format for Self-Published IP Geolocation
              Feeds", RFC 8805, DOI 10.17487/RFC8805, August 2020,
              <https://www.rfc-editor.org/info/rfc8805>.

   [RFC9051]  Melnikov, A., Ed. and B. Leiba, Ed., "Internet Message
              Access Protocol (IMAP) - Version 4rev2", RFC 9051,
              DOI 10.17487/RFC9051, August 2021,
              <https://www.rfc-editor.org/info/rfc9051>.

   [RFC9110]  Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,
              Ed., "HTTP Semantics", STD 97, RFC 9110,
              DOI 10.17487/RFC9110, June 2022,
              <https://www.rfc-editor.org/info/rfc9110>.

   [RFC9112]  Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,
              Ed., "HTTP/1.1", STD 99, RFC 9112, DOI 10.17487/RFC9112,
              June 2022, <https://www.rfc-editor.org/info/rfc9112>.

   [RFC9113]  Thomson, M., Ed. and C. Benfield, Ed., "HTTP/2", RFC 9113,
              DOI 10.17487/RFC9113, June 2022,
              <https://www.rfc-editor.org/info/rfc9113>.

   [RFC9260]  Stewart, R., Tüxen, M., and K. Nielsen, "Stream Control
              Transmission Protocol", RFC 9260, DOI 10.17487/RFC9260,
              June 2022, <https://www.rfc-editor.org/info/rfc9260>.

   [RFC9293]  Eddy, W., Ed., "Transmission Control Protocol (TCP)",
              STD 7, RFC 9293, DOI 10.17487/RFC9293, August 2022,
              <https://www.rfc-editor.org/info/rfc9293>.

   [I-D.ietf-i2nsf-capability-data-model]
              Hares, S., Jeong, J. P., Kim, J. T., Moskowitz, R., and Q.
              Lin, "I2NSF Capability YANG Data Model", Work in Progress,
              Internet-Draft, draft-ietf-i2nsf-capability-data-model-32,
              23 May 2022, <https://www.ietf.org/archive/id/draft-ietf-
              i2nsf-capability-data-model-32.txt>.

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   [I-D.ietf-i2nsf-nsf-monitoring-data-model]
              Jeong, J. P., Lingga, P., Hares, S., Xia, L. F., and H.
              Birkholz, "I2NSF NSF Monitoring Interface YANG Data
              Model", Work in Progress, Internet-Draft, draft-ietf-
              i2nsf-nsf-monitoring-data-model-20, 1 June 2022,
              <https://www.ietf.org/archive/id/draft-ietf-i2nsf-nsf-
              monitoring-data-model-20.txt>.

10.2.  Informative References

   [RFC3022]  Srisuresh, P. and K. Egevang, "Traditional IP Network
              Address Translator (Traditional NAT)", RFC 3022,
              DOI 10.17487/RFC3022, January 2001,
              <https://www.rfc-editor.org/info/rfc3022>.

   [RFC3444]  Pras, A. and J. Schoenwaelder, "On the Difference between
              Information Models and Data Models", RFC 3444,
              DOI 10.17487/RFC3444, January 2003,
              <https://www.rfc-editor.org/info/rfc3444>.

   [RFC3849]  Huston, G., Lord, A., and P. Smith, "IPv6 Address Prefix
              Reserved for Documentation", RFC 3849,
              DOI 10.17487/RFC3849, July 2004,
              <https://www.rfc-editor.org/info/rfc3849>.

   [RFC5737]  Arkko, J., Cotton, M., and L. Vegoda, "IPv4 Address Blocks
              Reserved for Documentation", RFC 5737,
              DOI 10.17487/RFC5737, January 2010,
              <https://www.rfc-editor.org/info/rfc5737>.

   [RFC8329]  Lopez, D., Lopez, E., Dunbar, L., Strassner, J., and R.
              Kumar, "Framework for Interface to Network Security
              Functions", RFC 8329, DOI 10.17487/RFC8329, February 2018,
              <https://www.rfc-editor.org/info/rfc8329>.

   [RFC9000]  Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based
              Multiplexed and Secure Transport", RFC 9000,
              DOI 10.17487/RFC9000, May 2021,
              <https://www.rfc-editor.org/info/rfc9000>.

   [GLOB]     "Linux Programmer's Manual - GLOB", 13 August 2020,
              <https://man7.org/linux/man-pages/man7/glob.7.html>.

   [IANA-ICMP-Parameters]
              Internet Assigned Numbers Authority (IANA), "Assigned
              Internet Protocol Numbers", February 2021,
              <https://www.iana.org/assignments/icmp-parameters/icmp-
              parameters.xhtml>.

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   [IANA-ICMPv6-Parameters]
              Internet Assigned Numbers Authority (IANA), "Internet
              Control Message Procotol version 6 (ICMPv6) Parameters",
              February 2021, <https://www.iana.org/assignments/icmpv6-
              parameters/icmpv6-parameters.xhtml>.

   [ISO-3166-1alpha2]
              ISO, "ISO 3166-1 decoding table",
              <http://www.iso.org/iso/home/standards/country_codes/iso-
              3166-1_decoding_table.htm>.

   [ISO-3166-2]
              ISO, "ISO 3166-2:2007",
              <http://www.iso.org/iso/home/standards/
              country_codes.htm#2012_iso3166-2>.

   [MISPCORE] Dulaunoy, A. and A. Iklody, "MISP Core", February 2022,
              <https://github.com/MISP/misp-rfc/blob/master/misp-core-
              format/raw.md.txt>.

   [OPENIOC]  Gibb, W., "OpenIOC 1.1 DRAFT", 2020,
              <https://github.com/fireeye/OpenIOC_1.1>.

   [STIX]     Jordan, B., Piazza, R., and T. Darley, "Structured Threat
              Information Expression (STIX)", STIX Version 2.1 
              https://docs.oasis-open.org/cti/stix/v2.1/os/stix-
              v2.1-os.html, June 2021.

   [TR-29.949-3GPP]
              3GPP, "Study on technical aspects on roaming end-to-end
              scenarios with Voice over LTE (VoLTE) IP Multimedia
              Subsystem (IMS) and other networks", 3GPP
              TR 29.949/Version 16.0.0, July 2020.

   [TR-21.915-3GPP]
              3GPP, "Summary of Rel-15 Work Items", 3GPP
              TR 21.915/Version 15.0.0, September 2019.

   [tcpdump]  Gerardi, R., "An introduction to using tcpdump at the
              Linux command line", September 2020,
              <https://opensource.com/article/18/10/introduction-
              tcpdump>.

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Appendix A.  Acknowledgments

   This document is a product by the I2NSF Working Group (WG) including
   WG Chairs (i.e., Linda Dunbar and Yoav Nir) and Diego Lopez.  This
   document took advantage of the review and comments from the following
   people: Roman Danyliw, Mahdi F.  Dachmehchi, Daeyoung Hyun, Jan
   Lindblad (YANG doctor), Tom Petch, Charlie Kaufman, Penglin Yang, and
   Jung-Soo Park.  The authors sincerely appreciate their sincere
   efforts and kind help.

   This work was supported by Institute of Information & Communications
   Technology Planning & Evaluation (IITP) grant funded by the Korea
   MSIT (Ministry of Science and ICT) (R-20160222-002755, Cloud based
   Security Intelligence Technology Development for the Customized
   Security Service Provisioning).  This work was supported in part by
   the IITP (2020-0-00395-003, Standard Development of Blockchain based
   Network Management Automation Technology).

Appendix B.  Contributors

   The following are co-authors of this document:

   Patrick Lingga - Department of Electrical and Computer Engineering,
   Sungkyunkwan University, 2066 Seo-ro Jangan-gu, Suwon, Gyeonggi-do
   16419, Republic of Korea.  EMail: patricklink@skku.edu

   Jinyong Tim Kim - Department of Electronic, Electrical and Computer
   Engineering, Sungkyunkwan University, 2066 Seo-ro Jangan-gu, Suwon,
   Gyeonggi-do 16419, Republic of Korea.  EMail: timkim@skku.edu

   Hyoungshick Kim - Department of Computer Science and Engineering,
   Sungkyunkwan University, 2066 Seo-ro Jangan-gu, Suwon, Gyeonggi-do
   16419, Republic of Korea.  EMail: hyoung@skku.edu

   Eunsoo Kim - Department of Electronic, Electrical and Computer
   Engineering, Sungkyunkwan University, 2066 Seo-ro Jangan-gu, Suwon,
   Gyeonggi-do 16419, Republic of Korea.  EMail: eskim86@skku.edu

   Seungjin Lee - Department of Electronic, Electrical and Computer
   Engineering, Sungkyunkwan University, 2066 Seo-ro Jangan-gu, Suwon,
   Gyeonggi-do 16419, Republic of Korea.  EMail: jine33@skku.edu

   Anil Lohiya - Juniper Networks, 1133 Innovation Way, Sunnyvale, CA
   94089, US.  EMail: alohiya@juniper.net

   Dave Qi - Bloomberg, 731 Lexington Avenue, New York, NY 10022, US.
   EMail: DQI@bloomberg.net

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   Nabil Bitar - Nokia, 755 Ravendale Drive, Mountain View, CA 94043,
   US.  EMail: nabil.bitar@nokia.com

   Senad Palislamovic - Nokia, 755 Ravendale Drive, Mountain View, CA
   94043, US.  EMail: senad.palislamovic@nokia.com

   Liang Xia - Huawei, 101 Software Avenue, Nanjing, Jiangsu 210012,
   China.  EMail: Frank.Xialiang@huawei.com

Appendix C.  Changes from draft-ietf-i2nsf-consumer-facing-interface-
             dm-23

   The following changes are made from draft-ietf-i2nsf-consumer-facing-
   interface-dm-23:

   *  This version reflected the AD Review by Roman Danyliw.

Authors' Addresses

   Jaehoon Paul Jeong (editor)
   Department of Computer Science and Engineering
   Sungkyunkwan University
   2066 Seobu-Ro, Jangan-Gu
   Suwon
   Gyeonggi-Do
   16419
   Republic of Korea
   Phone: +82 31 299 4957
   Email: pauljeong@skku.edu
   URI:   http://iotlab.skku.edu/people-jaehoon-jeong.php

   Chaehong Chung
   Department of Electronic, Electrical and Computer Engineering
   Sungkyunkwan University
   2066 Seobu-Ro, Jangan-Gu
   Suwon
   Gyeonggi-Do
   16419
   Republic of Korea
   Phone: +82 31 299 4957
   Email: darkhong@skku.edu

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   Tae-Jin Ahn
   Korea Telecom
   70 Yuseong-Ro, Yuseong-Gu
   Daejeon
   305-811
   Republic of Korea
   Phone: +82 42 870 8409
   Email: taejin.ahn@kt.com

   Rakesh Kumar
   Juniper Networks
   1133 Innovation Way
   Sunnyvale, CA 94089
   United States of America
   Email: rkkumar@juniper.net

   Susan Hares
   Huawei
   7453 Hickory Hill
   Saline, MI 48176
   United States of America
   Phone: +1-734-604-0332
   Email: shares@ndzh.com

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