Internet-Draft A YANG Data Model for IP-TFS August 2022
Fedyk & Hopps Expires 17 February 2023 [Page]
Workgroup:
Network Working Group
Internet-Draft:
draft-ietf-ipsecme-yang-iptfs-13
Published:
Intended Status:
Standards Track
Expires:
Authors:
D. Fedyk
LabN Consulting, L.L.C.
C. Hopps
LabN Consulting, L.L.C.

A YANG Data Model for IP Traffic Flow Security

Abstract

This document describes a yang module for the management of IP Traffic Flow Security additions to IKEv2 and IPsec.

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 17 February 2023.

Table of Contents

1. Introduction

This document defines a YANG module [RFC7950] for the management of the IP Traffic Flow Security (IP-TFS) extensions as defined in [I-D.ietf-ipsecme-iptfs]. IP-TFS provides enhancements to an IPsec tunnel Security Association to provide improved traffic confidentiality. Traffic confidentiality reduces the ability of traffic analysis to determine identity and correlate observable traffic patterns. IP-TFS offers efficiency when aggregating traffic in fixed size IPsec tunnel packets.

The YANG data model in this document conforms to the Network Management Datastore Architecture (NMDA) defined in [RFC8342].

The published YANG modules for IPsec are defined in [RFC9061]. This document uses these models as a general IPsec model that is augmented for IP-TFS. The models in [RFC9061] provide for both an IKE and an IKELESS model.

1.1. Terminology & Concepts

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 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.

2. Overview

This document defines configuration and operational parameters of IP traffic flow security (IP-TFS). IP-TFS, defined in [I-D.ietf-ipsecme-iptfs], defines a security association for tunnel mode IPsec with characteristics that improve traffic confidentiality and reduce bandwidth efficiency loss. These documents assume familiarity with IP security concepts described in [RFC4301].

IP-TFS uses tunnel mode to improve confidentiality by hiding inner packet identifiable information, packet size and packet timing. IP-TFS provides a general capability allowing aggregation of multiple packets in uniform size outer tunnel IPsec packets. It maintains the outer packet size by utilizing combinations of aggregating, padding and fragmenting inner packets to fill out the IPsec outer tunnel packet. Zero byte padding is used to fill the packet when no data is available to send.

This document specifies an extensible configuration model for IP-TFS. This version utilizes the capabilities of IP-TFS to configure fixed size IP-TFS Packets that are transmitted at a constant rate. This model is structured to allow for different types of operation through future augmentation.

The IP-TFS YANG module augments IPsec YANG model from [RFC9061]. IP-TFS makes use of IPsec tunnel mode and adds a small number configuration items to tunnel mode IPsec. As defined in [I-D.ietf-ipsecme-iptfs], any SA configured to use IP-TFS supports only IP-TFS packets i.e. no mixed IPsec modes.

The behavior for IP-TFS is controlled by the source. The self-describing format of an IP-TFS packets allows a sending side to adjust the packet-size and timing independently from any receiver. Both directions are also independent, e.g. IP-TFS may be run only in one direction. This means that counters, which are created here for both directions may be 0 or not updated in the case of an SA that uses IP-TFS only in on direction.

Cases where IP-TFS statistics are active for one direction:

Case where IP-TFS statistics are for both directions:

The IP-TFS model support IP-TFS configuration and operational data.

This YANG module supports configuration of fixed size and fixed rate packets, and elements that may be augmented to support future configuration. The protocol specification [I-D.ietf-ipsecme-iptfs], goes beyond this simple fixed mode of operation by defining a general format for any type of scheme. In this document the outer IPsec packets can be sent with fixed or variable size (without padding). The configuration allows the fixed packet size to be determined by the path MTU. The fixed packet size can also be configured if a value lower than the path MTU is desired.

Other configuration items include:

The YANG operational data allows the readout of the configured parameters as well as the per SA statistics and error counters for IP-TFS. Per SA IPsec packet statistics are provided as a feature and per SA IP-TFS specific statistics as another feature. Both sets of statistics augment the IPsec YANG models with counters that allow observation of IP-TFS packet efficiency.

[RFC9061] has a set of IPsec YANG management objects. IP-TFS YANG augments the IKE and the IKELESS models. In these models the Security Policy database entry and Security Association entry for an IPsec Tunnel can be augmented with IP-TFS.

3. YANG Management

3.1. YANG Tree

The following is the YANG tree diagram ([RFC8340]) for the IP-TFS extensions.


module: ietf-ipsec-iptfs

  augment /nsfike:ipsec-ike/nsfike:conn-entry/nsfike:spd
            /nsfike:spd-entry/nsfike:ipsec-policy-config
            /nsfike:processing-info/nsfike:ipsec-sa-cfg:
    +--rw traffic-flow-security
       +--rw congestion-control?           boolean
       +--rw packet-size
       |  +--rw use-path-mtu-discovery?   boolean
       |  +--rw outer-packet-size?        uint16
       +--rw (tunnel-rate)?
       |  +--:(l2-fixed-rate)
       |  |  +--rw l2-fixed-rate?          yang:counter64
       |  +--:(l3-fixed-rate)
       |     +--rw l3-fixed-rate?          yang:counter64
       +--rw dont-fragment?                boolean
       +--rw max-aggregation-time?         decimal64
       +--rw window-size?                  uint16
       +--rw send-immediately?             boolean
       +--rw lost-packet-timer-interval?   decimal64
  augment /nsfike:ipsec-ike/nsfike:conn-entry/nsfike:child-sa-info:
    +--ro traffic-flow-security
       +--ro congestion-control?           boolean
       +--ro packet-size
       |  +--ro use-path-mtu-discovery?   boolean
       |  +--ro outer-packet-size?        uint16
       +--ro (tunnel-rate)?
       |  +--:(l2-fixed-rate)
       |  |  +--ro l2-fixed-rate?          yang:counter64
       |  +--:(l3-fixed-rate)
       |     +--ro l3-fixed-rate?          yang:counter64
       +--ro dont-fragment?                boolean
       +--ro max-aggregation-time?         decimal64
       +--ro window-size?                  uint16
       +--ro send-immediately?             boolean
       +--ro lost-packet-timer-interval?   decimal64
  augment /nsfikels:ipsec-ikeless/nsfikels:spd/nsfikels:spd-entry
            /nsfikels:ipsec-policy-config/nsfikels:processing-info
            /nsfikels:ipsec-sa-cfg:
    +--rw traffic-flow-security
       +--rw congestion-control?           boolean
       +--rw packet-size
       |  +--rw use-path-mtu-discovery?   boolean
       |  +--rw outer-packet-size?        uint16
       +--rw (tunnel-rate)?
       |  +--:(l2-fixed-rate)
       |  |  +--rw l2-fixed-rate?          yang:counter64
       |  +--:(l3-fixed-rate)
       |     +--rw l3-fixed-rate?          yang:counter64
       +--rw dont-fragment?                boolean
       +--rw max-aggregation-time?         decimal64
       +--rw window-size?                  uint16
       +--rw send-immediately?             boolean
       +--rw lost-packet-timer-interval?   decimal64
  augment /nsfikels:ipsec-ikeless/nsfikels:sad/nsfikels:sad-entry:
    +--ro traffic-flow-security
       +--ro congestion-control?           boolean
       +--ro packet-size
       |  +--ro use-path-mtu-discovery?   boolean
       |  +--ro outer-packet-size?        uint16
       +--ro (tunnel-rate)?
       |  +--:(l2-fixed-rate)
       |  |  +--ro l2-fixed-rate?          yang:counter64
       |  +--:(l3-fixed-rate)
       |     +--ro l3-fixed-rate?          yang:counter64
       +--ro dont-fragment?                boolean
       +--ro max-aggregation-time?         decimal64
       +--ro window-size?                  uint16
       +--ro send-immediately?             boolean
       +--ro lost-packet-timer-interval?   decimal64
  augment /nsfike:ipsec-ike/nsfike:conn-entry/nsfike:child-sa-info:
    +--ro ipsec-stats {ipsec-stats}?
    |  +--ro tx-pkts?        yang:counter64
    |  +--ro tx-octets?      yang:counter64
    |  +--ro tx-drop-pkts?   yang:counter64
    |  +--ro rx-pkts?        yang:counter64
    |  +--ro rx-octets?      yang:counter64
    |  +--ro rx-drop-pkts?   yang:counter64
    +--ro iptfs-inner-pkt-stats {iptfs-stats}?
    |  +--ro tx-pkts?              yang:counter64
    |  +--ro tx-octets?            yang:counter64
    |  +--ro rx-pkts?              yang:counter64
    |  +--ro rx-octets?            yang:counter64
    |  +--ro rx-incomplete-pkts?   yang:counter64
    +--ro iptfs-outer-pkt-stats {iptfs-stats}?
       +--ro tx-all-pad-pkts?       yang:counter64
       +--ro tx-all-pad-octets?     yang:counter64
       +--ro tx-extra-pad-pkts?     yang:counter64
       +--ro tx-extra-pad-octets?   yang:counter64
       +--ro rx-all-pad-pkts?       yang:counter64
       +--ro rx-all-pad-octets?     yang:counter64
       +--ro rx-extra-pad-pkts?     yang:counter64
       +--ro rx-extra-pad-octets?   yang:counter64
       +--ro rx-errored-pkts?       yang:counter64
       +--ro rx-missed-pkts?        yang:counter64
  augment /nsfikels:ipsec-ikeless/nsfikels:sad/nsfikels:sad-entry:
    +--ro ipsec-stats {ipsec-stats}?
    |  +--ro tx-pkts?        yang:counter64
    |  +--ro tx-octets?      yang:counter64
    |  +--ro tx-drop-pkts?   yang:counter64
    |  +--ro rx-pkts?        yang:counter64
    |  +--ro rx-octets?      yang:counter64
    |  +--ro rx-drop-pkts?   yang:counter64
    +--ro iptfs-inner-pkt-stats {iptfs-stats}?
    |  +--ro tx-pkts?              yang:counter64
    |  +--ro tx-octets?            yang:counter64
    |  +--ro rx-pkts?              yang:counter64
    |  +--ro rx-octets?            yang:counter64
    |  +--ro rx-incomplete-pkts?   yang:counter64
    +--ro iptfs-outer-pkt-stats {iptfs-stats}?
       +--ro tx-all-pad-pkts?       yang:counter64
       +--ro tx-all-pad-octets?     yang:counter64
       +--ro tx-extra-pad-pkts?     yang:counter64
       +--ro tx-extra-pad-octets?   yang:counter64
       +--ro rx-all-pad-pkts?       yang:counter64
       +--ro rx-all-pad-octets?     yang:counter64
       +--ro rx-extra-pad-pkts?     yang:counter64
       +--ro rx-extra-pad-octets?   yang:counter64
       +--ro rx-errored-pkts?       yang:counter64
       +--ro rx-missed-pkts?        yang:counter64

3.2. YANG Module

The following is the YANG module for managing the IP-TFS extensions. The model contains references to [I-D.ietf-ipsecme-iptfs] and [RFC5348].

<CODE BEGINS> file "ietf-ipsec-iptfs@2022-05-17.yang"

module ietf-ipsec-iptfs {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-ipsec-iptfs";
  prefix iptfs;

  import ietf-i2nsf-ike {
    prefix nsfike;
  }
  import ietf-i2nsf-ikeless {
    prefix nsfikels;
  }
  import ietf-yang-types {
    prefix yang;
  }

  organization
    "IETF IPSECME Working Group (IPSECME)";
  contact
    "WG Web:  <https://tools.ietf.org/wg/ipsecme/>
     WG List: <mailto:ipsecme@ietf.org>

     Author: Don Fedyk
             <mailto:dfedyk@labn.net>

     Author: Christian Hopps
             <mailto:chopps@chopps.org>";

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

  description
    "This module defines the configuration and operational state for
     managing the IP Traffic Flow Security functionality [RFC XXXX].

     Copyright (c) 2021 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 Simplified 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://tools.ietf.org/html/rfcXXXX); see the RFC itself for
     full legal notices.";

  revision 2022-05-17 {
    description
      "Initial Revision";
    reference
      "RFC XXXX: IP Traffic Flow Security YANG Module";
  }

  feature ipsec-stats {
    description
      "This feature indicates the device supports
       per SA IPsec statistics";
  }

  feature iptfs-stats {
    description
      "This feature indicates the device supports
       per SA IP Traffic Flow Security statistics";
  }

  /*--------------------*/
  /*   groupings        */
  /*--------------------*/

  grouping ipsec-tx-stat-grouping {
    description
      "IPsec outbound statistics";
    leaf tx-pkts {
      type yang:counter64;
      config false;
      description
        "Outbound Packet count";
    }
    leaf tx-octets {
      type yang:counter64;
      config false;
      description
        "Outbound Packet bytes";
    }
    leaf tx-drop-pkts {
      type yang:counter64;
      config false;
      description
        "Outbound dropped packets count";
    }
  }

  grouping ipsec-rx-stat-grouping {
    description
      "IPsec inbound statistics";
    leaf rx-pkts {
      type yang:counter64;
      config false;
      description
        "Inbound Packet count";
    }
    leaf rx-octets {
      type yang:counter64;
      config false;
      description
        "Inbound Packet bytes";
    }
    leaf rx-drop-pkts {
      type yang:counter64;
      config false;
      description
        "Inbound dropped packets count";
    }
  }

  grouping iptfs-inner-tx-stat-grouping {
    description
      "IP-TFS outbound inner packet statistics";
    leaf tx-pkts {
      type yang:counter64;
      config false;
      description
        "Total number of IP-TFS inner packets sent. This
         count is whole packets only.  A fragmented packet
         counts as one packet";
      reference
        "draft-ietf-ipsecme-iptfs";
    }
    leaf tx-octets {
      type yang:counter64;
      config false;
      description
        "Total number of IP-TFS inner octets sent.  This is
         inner packet octets only.  Does not count padding.";
      reference
        "draft-ietf-ipsecme-iptfs";
    }
  }

  grouping iptfs-outer-tx-stat-grouping {
    description
      "IP-TFS outbound inner packet statistics";
    leaf tx-all-pad-pkts {
      type yang:counter64;
      config false;
      description
        "Total number of transmitted IP-TFS packets that
         were all padding with no inner packet data.";
      reference
        "draft-ietf-ipsecme-iptfs section 2.2.3";
    }
    leaf tx-all-pad-octets {
      type yang:counter64;
      config false;
      description
        "Total number transmitted octets of padding added to
         IP-TFS packets with no inner packet data.";
      reference
        "draft-ietf-ipsecme-iptfs section 2.2.3";
    }
    leaf tx-extra-pad-pkts {
      type yang:counter64;
      config false;
      description
        "Total number of transmitted outer IP-TFS packets
         that included some padding.";
      reference
        "draft-ietf-ipsecme-iptfs section 2.2.3.1";
    }
    leaf tx-extra-pad-octets {
      type yang:counter64;
      config false;
      description
        "Total number of transmitted octets of padding added
         to outer IP-TFS packets with data.";
      reference
        "draft-ietf-ipsecme-iptfs section 2.2.3.1";
    }
  }

  grouping iptfs-inner-rx-stat-grouping {
    description
      "IP-TFS inner packet inbound statistics";
    leaf rx-pkts {
      type yang:counter64;
      config false;
      description
        "Total number of IP-TFS inner packets received.";
      reference
        "draft-ietf-ipsecme-iptfs section 2.2";
    }
    leaf rx-octets {
      type yang:counter64;
      config false;
      description
        "Total number of IP-TFS inner octets received.  Does
         not include padding or overhead";
      reference
        "draft-ietf-ipsecme-iptfs section 2.2";
    }
    leaf rx-incomplete-pkts {
      type yang:counter64;
      config false;
      description
        "Total number of IP-TFS inner packets that were
         incomplete.  Usually this is due to fragments not
         received. Also, this may be due to misordering or
         errors in received outer packets.";
      reference
        "draft-ietf-ipsecme-iptfs";
    }
  }

  grouping iptfs-outer-rx-stat-grouping {
    description
      "IP-TFS outer packet inbound statistics";
    leaf rx-all-pad-pkts {
      type yang:counter64;
      config false;
      description
        "Total number of received IP-TFS packets that were
         all padding with no inner packet data.";
      reference
        "draft-ietf-ipsecme-iptfs section 2.2.3";
    }
    leaf rx-all-pad-octets {
      type yang:counter64;
      config false;
      description
        "Total number received octets of padding added to
         IP-TFS packets with no inner packet data.";
      reference
        "draft-ietf-ipsecme-iptfs section 2.2.3";
    }
    leaf rx-extra-pad-pkts {
      type yang:counter64;
      config false;
      description
        "Total number of received outer IP-TFS packets that
         included some padding.";
      reference
        "draft-ietf-ipsecme-iptfs section 2.2.3.1";
    }
    leaf rx-extra-pad-octets {
      type yang:counter64;
      config false;
      description
        "Total number of received octets of padding added to
         outer IP-TFS packets with data.";
      reference
        "draft-ietf-ipsecme-iptfs section 2.2.3.1";
    }
    leaf rx-errored-pkts {
      type yang:counter64;
      config false;
      description
        "Total number of IP-TFS outer packets dropped due to
         errors.";
      reference
        "draft-ietf-ipsecme-iptfs";
    }
    leaf rx-missed-pkts {
      type yang:counter64;
      config false;
      description
        "Total number of IP-TFS outer packets missing
         indicated by missing sequence number.";
      reference
        "draft-ietf-ipsecme-iptfs";
    }
  }

  grouping iptfs-config {
    description
      "This is the grouping for iptfs configuration";
    container traffic-flow-security {
      description
        "Configure the IPSec TFS in Security
         Association Database (SAD)";
      leaf congestion-control {
        type boolean;
        default "true";
        description
          "When set to true, the default, this enables the
           congestion control on-the-wire exchange of data that is
           required by congestion control algorithms as defined by
           RFC 5348.  When set to false, IP-TFS sends fixed-sized
           packets over an IP-TFS tunnel at a constant rate.";
        reference
          "draft-ietf-ipsecme-iptfs section 2.5.2, RFC 5348";
      }
      container packet-size {
        description
          "Packet size is either auto-discovered or manually
           configured.";
        leaf use-path-mtu-discovery {
          type boolean;
          default "true";
          description
            "Utilize path mtu discovery to determine maximum
             IP-TFS packet size. If the packet size is explicitly
             configured, then it will only be adjusted downward if
             use-path-mtu-discovery is set.";
          reference
            "draft-ietf-ipsecme-iptfs section 4.2";
        }
        leaf outer-packet-size {
          type uint16;
          units bytes;
          description
            "On transmission, the size of the outer encapsulating
             tunnel packet (i.e., the IP packet containing the ESP
             payload).";
          reference
            "draft-ietf-ipsecme-iptfs section 4.2";
        }
      }
      choice tunnel-rate {
        description
          "TFS bit rate may be specified at layer 2 wire
           rate or layer 3 packet rate";
        leaf l2-fixed-rate {
          type yang:counter64;
          description
            "On transmission, target bandwidth/bit rate in bps
             for iptfs tunnel. This fixed rate is the nominal
             timing for the fixed size packet. If congestion
             control is enabled the rate may be adjusted down (or
             up if unset).";
          reference
            "draft-ietf-ipsecme-iptfs section 4.1";
        }
        leaf l3-fixed-rate {
          type yang:counter64;
          description
            "On transmission, target bandwidth/bit rate in bps
             for iptfs tunnel.  This fixed rate is the nominal
             timing for the fixed size packet.  If congestion
             control is enabled the rate may be adjusted down (or
             up if unset).";
          reference
            "draft-ietf-ipsecme-iptfs section 4.1";
        }
      }
      leaf dont-fragment {
        type boolean;
        default "false";
        description
          "On transmission, disable packet fragmentation across
           consecutive iptfs tunnel packets; inner packets larger
           than what can be transmitted in outer packets will be
           dropped.";
        reference
          "draft-ietf-ipsecme-iptfs section 2.2.4 and 6.4.1";
      }
      leaf max-aggregation-time {
        type decimal64 {
          fraction-digits 6;
        }
        units "milliseconds";
        description
          "On transmission, maximum aggregation time is the
           maximum length of time a received inner packet can be
           held prior to transmission in the iptfs tunnel. Inner
           packets that would be held longer than this time, based
           on the current tunnel configuration will be dropped
           rather than be queued for transmission.  Maximum
           aggregation time is configurable in milliseconds or
           fractional milliseconds down to 1 nanosecond.";
      }
      leaf window-size {
        type uint16 {
          range "0..65535";
        }
        description
          "On reception, the maximum number of out-of-order
           packets that will be reordered by an iptfs receiver
           while performing the reordering operation. The value 0
           disables any reordering.";
        reference
          "draft-ietf-ipsecme-iptfs section 2.2.3";
      }
      leaf send-immediately {
        type boolean;
        default false;
        description
          "On reception, send inner packets as soon as possible, do
           not wait for lost or misordered outer packets.
           Selecting this option reduces the inner (user) packet
           delay but can amplify out-of-order delivery of the
           inner packet stream in the presence of packet
           aggregation and any reordering.";
        reference
          "draft-ietf-ipsecme-iptfs section 2.5";
      }
      leaf lost-packet-timer-interval {
        type decimal64 {
          fraction-digits 6;
        }
        units "milliseconds";
        description
          "On reception, this interval defines the length of time
           an iptfs receiver will wait for a missing packet before
           considering it lost.  If not using send-immediately,
           then each lost packet will delay inner (user) packets
           until this timer expires. Setting this value too low
           can impact reordering and reassembly. The value is
           configurable in milliseconds or fractional milliseconds
           down to 1 nanosecond.";
         reference
          "draft-ietf-ipsecme-iptfs section 2.2.3";
      }
    }
  }

  /*
   * IP-TFS ike configuration
   */

  augment "/nsfike:ipsec-ike/nsfike:conn-entry/nsfike:spd/"
        + "nsfike:spd-entry/"
        + "nsfike:ipsec-policy-config/"
        + "nsfike:processing-info/"
        + "nsfike:ipsec-sa-cfg" {
    description
      "IP-TFS configuration for this policy.";
    uses iptfs-config;
  }

  augment "/nsfike:ipsec-ike/nsfike:conn-entry/"
        + "nsfike:child-sa-info" {
    description
      "IP-TFS configured on this SA.";
    uses iptfs-config {
      refine "traffic-flow-security" {
        config false;
      }
    }
  }

  /*
   * IP-TFS ikeless configuration
   */

  augment "/nsfikels:ipsec-ikeless/nsfikels:spd/"
        + "nsfikels:spd-entry/"
        + "nsfikels:ipsec-policy-config/"
        + "nsfikels:processing-info/"
        + "nsfikels:ipsec-sa-cfg" {
    description
      "IP-TFS configuration for this policy.";
    uses iptfs-config;
  }

  augment "/nsfikels:ipsec-ikeless/nsfikels:sad/"
        + "nsfikels:sad-entry" {
    description
      "IP-TFS configured on this SA.";
    uses iptfs-config {
      refine "traffic-flow-security" {
        config false;
      }
    }
  }

  /*
   * packet counters
   */

  augment "/nsfike:ipsec-ike/nsfike:conn-entry/"
        + "nsfike:child-sa-info" {
    description
      "Per SA Counters";
    container ipsec-stats {
      if-feature "ipsec-stats";
      config false;
      description
        "IPsec per SA packet counters.";
      uses ipsec-tx-stat-grouping {
        //when "direction = 'outbound'";
      }
      uses ipsec-rx-stat-grouping {
        //when "direction = 'inbound'";
      }
    }
    container iptfs-inner-pkt-stats {
      if-feature "iptfs-stats";
      config false;
      description
        "IPTFS per SA inner packet counters.";
      uses iptfs-inner-tx-stat-grouping {
        //when "direction = 'outbound'";
      }
      uses iptfs-inner-rx-stat-grouping {
        //when "direction = 'inbound'";
      }
    }
    container iptfs-outer-pkt-stats {
      if-feature "iptfs-stats";
      config false;
      description
        "IPTFS per SA outer packets counters.";
      uses iptfs-outer-tx-stat-grouping {
        //when "direction = 'outbound'";
      }
      uses iptfs-outer-rx-stat-grouping {
        //when "direction = 'inbound'";
      }
    }
  }

  /*
   * packet counters
   */

  augment "/nsfikels:ipsec-ikeless/nsfikels:sad/"
        + "nsfikels:sad-entry" {
    description
      "Per SA Counters";
    container ipsec-stats {
      if-feature "ipsec-stats";
      config false;
      description
        "IPsec per SA packet counters.";
      uses ipsec-tx-stat-grouping {
        //when "direction = 'outbound'";
      }
      uses ipsec-rx-stat-grouping {
        //when "direction = 'inbound'";
      }
    }
    container iptfs-inner-pkt-stats {
      if-feature "iptfs-stats";
      config false;
      description
        "IPTFS per SA inner packet counters.";
      uses iptfs-inner-tx-stat-grouping {
        //when "direction = 'outbound'";
      }
      uses iptfs-inner-rx-stat-grouping {
        //when "direction = 'inbound'";
      }
    }
    container iptfs-outer-pkt-stats {
      if-feature "iptfs-stats";
      config false;
      description
        "IPTFS per SA outer packets counters.";
      uses iptfs-outer-tx-stat-grouping {
        //when "direction = 'outbound'";
      }
      uses iptfs-outer-rx-stat-grouping {
        //when "direction = 'inbound'";
      }
    }

  }
}

<CODE ENDS>

4. IANA Considerations

4.1. Updates to the IETF XML Registry

This document registers a URI in the "IETF XML Registry" [RFC3688]. Following the format in [RFC3688], the following registration has been made:

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

4.2. Updates to the YANG Module Names Registry

This document registers one YANG module in the "YANG Module Names" registry [RFC6020]. Following the format in [RFC6020], the following registration has been made:

name:
ietf-ipsec-iptfs
namespace:
urn:ietf:params:xml:ns:yang:ietf-ipsec-iptfs
prefix:
iptfs
reference:
RFC XXXX (RFC Ed.: replace XXXX with actual RFC number and remove this note.)

5. Security Considerations

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

The Network Configuration Access Control Model (NACM) [RFC8341] provides the means to restrict access for particular NETCONF or RESTCONF users to a preconfigured subset of all available NETCONF or RESTCONF protocol operations and content.

Certain data nodes defined in this YANG module are writable/creatable/deletable. These changes can enable, disable and modify the behavior of IP traffic flow security, for the implications regarding these types of changes consult the [I-D.ietf-ipsecme-iptfs] which defines the functionality. The relevant sub-trees or nodes are:

../traffic-flow-security:
Enabling IP traffic flow security is controlled by setting the entries under traffic-flow-security in IKE or IKE-less models. IP traffic flow security is set either to be congestion sensitive or a fixed rate by setting parameters in this sub-tree.

Certain readable data nodes in this YANG module may be considered sensitive or vulnerable in some network environments. While IP-TFS hides the traffic flows through the network, IP-TFS YANG statistics could reveal some information about traffic flows. Therefore, access to IP-TFS YANG statistics also needs to be protected from third party observation. These IP-TFS YANG statistics can be found at:

../iptfs-inner-pkt-stats and ../iptfs-outer-pkt-stats:
Access to IP traffic flow security statistics can provide information that IP traffic flow security obscures such as the true activity of the flows using IP traffic flow security.

6. Acknowledgements

The authors would like to thank Eric Kinzie, Juergen Schoenwaelder, Lou Berger and Tero Kivinen for their feedback and review on the YANG model.

7. References

7.1. Normative References

[I-D.ietf-ipsecme-iptfs]
Hopps, C., "IP-TFS: Aggregation and Fragmentation Mode for ESP and its Use for IP Traffic Flow Security", Work in Progress, Internet-Draft, draft-ietf-ipsecme-iptfs-12, , <https://www.ietf.org/archive/id/draft-ietf-ipsecme-iptfs-12.txt>.
[RFC2119]
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/info/rfc2119>.
[RFC4301]
Kent, S. and K. Seo, "Security Architecture for the Internet Protocol", RFC 4301, DOI 10.17487/RFC4301, , <https://www.rfc-editor.org/info/rfc4301>.
[RFC6020]
Bjorklund, M., Ed., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, , <https://www.rfc-editor.org/info/rfc6020>.
[RFC7950]
Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, , <https://www.rfc-editor.org/info/rfc7950>.
[RFC8174]
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <https://www.rfc-editor.org/info/rfc8174>.
[RFC8342]
Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K., and R. Wilton, "Network Management Datastore Architecture (NMDA)", RFC 8342, DOI 10.17487/RFC8342, , <https://www.rfc-editor.org/info/rfc8342>.
[RFC9061]
Marin-Lopez, R., Lopez-Millan, G., and F. Pereniguez-Garcia, "A YANG Data Model for IPsec Flow Protection Based on Software-Defined Networking (SDN)", RFC 9061, DOI 10.17487/RFC9061, , <https://www.rfc-editor.org/info/rfc9061>.

7.2. Informative References

[RFC3688]
Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, , <https://www.rfc-editor.org/info/rfc3688>.
[RFC5348]
Floyd, S., Handley, M., Padhye, J., and J. Widmer, "TCP Friendly Rate Control (TFRC): Protocol Specification", RFC 5348, DOI 10.17487/RFC5348, , <https://www.rfc-editor.org/info/rfc5348>.
[RFC6241]
Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., and A. Bierman, Ed., "Network Configuration Protocol (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, , <https://www.rfc-editor.org/info/rfc6241>.
[RFC6242]
Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, , <https://www.rfc-editor.org/info/rfc6242>.
[RFC8040]
Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, , <https://www.rfc-editor.org/info/rfc8040>.
[RFC8340]
Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", BCP 215, RFC 8340, DOI 10.17487/RFC8340, , <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, , <https://www.rfc-editor.org/info/rfc8341>.
[RFC8446]
Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 8446, DOI 10.17487/RFC8446, , <https://www.rfc-editor.org/info/rfc8446>.

Appendix A. Examples

The following examples show configuration and operational data for the IKE-less and IKE cases using XML and JSON. Also, the operational statistics for the IKE-less case is illustrated.

A.1. Example XML Configuration

This example illustrates configuration for IP-TFS in the IKE-less case. Note that since this augments the IPsec IKE-less schema only minimal a IKE-less configuration to satisfy the schema has been populated.

<i:ipsec-ikeless
  xmlns:i="urn:ietf:params:xml:ns:yang:ietf-i2nsf-ikeless"
  xmlns:tfs="urn:ietf:params:xml:ns:yang:ietf-ipsec-iptfs">
  <i:spd>
    <i:spd-entry>
      <i:name>protect-policy-1</i:name>
      <i:direction>outbound</i:direction>
      <i:ipsec-policy-config>
        <i:traffic-selector>
          <i:local-prefix>192.0.2.0/16</i:local-prefix>
          <i:remote-prefix>198.51.100.0/16</i:remote-prefix>
        </i:traffic-selector>
        <i:processing-info>
          <i:action>protect</i:action>
          <i:ipsec-sa-cfg>
            <tfs:traffic-flow-security>
             <tfs:congestion-control>true</tfs:congestion-control>
              <tfs:packet-size>
                <tfs:use-path-mtu-discovery
                   >true</tfs:use-path-mtu-discovery>
              </tfs:packet-size>
              <tfs:l2-fixed-rate>1000000000</tfs:l2-fixed-rate>
              <tfs:max-aggregation-time
                 >0.1</tfs:max-aggregation-time>
              <tfs:window-size>5</tfs:window-size>
              <tfs:send-immediately>false</tfs:send-immediately>
              <tfs:lost-packet-timer-interval
                 >0.2</tfs:lost-packet-timer-interval>
            </tfs:traffic-flow-security>
          </i:ipsec-sa-cfg>
        </i:processing-info>
      </i:ipsec-policy-config>
    </i:spd-entry>
  </i:spd>
</i:ipsec-ikeless>
Figure 1: Example IP-TFS XML configuration

A.2. Example XML Operational Data

This example illustrates operational data for IP-TFS in the IKE-less case. Note that since this augments the IPsec IKE-less schema only minimal IKE-less configuration to satisfy the schema has been populated.

<i:ipsec-ikeless
  xmlns:i="urn:ietf:params:xml:ns:yang:ietf-i2nsf-ikeless"
  xmlns:tfs="urn:ietf:params:xml:ns:yang:ietf-ipsec-iptfs">
  <i:sad>
    <i:sad-entry>
      <i:name>sad-1</i:name>
      <i:ipsec-sa-config>
        <i:spi>1</i:spi>
        <i:traffic-selector>
          <i:local-prefix>2001:DB8::0/16</i:local-prefix>
          <i:remote-prefix>2001:DB8::1:0/16</i:remote-prefix>
        </i:traffic-selector>
      </i:ipsec-sa-config>
      <tfs:traffic-flow-security>
        <tfs:congestion-control>true</tfs:congestion-control>
        <tfs:packet-size>
          <tfs:use-path-mtu-discovery
            >true</tfs:use-path-mtu-discovery>
        </tfs:packet-size>
        <tfs:l2-fixed-rate>1000000000</tfs:l2-fixed-rate>
        <tfs:max-aggregation-time>0.100</tfs:max-aggregation-time>
        <tfs:window-size>0</tfs:window-size>
        <tfs:send-immediately>true</tfs:send-immediately>
        <tfs:lost-packet-timer-interval
          >0.200</tfs:lost-packet-timer-interval>
      </tfs:traffic-flow-security>
    </i:sad-entry>
  </i:sad>
</i:ipsec-ikeless>
Figure 2: Example IP-TFS XML Operational data

A.3. Example JSON Configuration

This example illustrates config data for IP-TFS in the IKE case. Note that since this augments the IPsec IKE schema only minimal ike configuration to satisfy the schema has been populated.

{
  "ietf-i2nsf-ike:ipsec-ike": {
    "ietf-i2nsf-ike:conn-entry": [
      {
        "name": "my-peer-connection",
        "ike-sa-encr-alg": [
          {
            "id": 1,
            "algorithm-type": 12,
            "key-length": 128
          }
          ],
          "local": {
            "local-pad-entry-name": "local-1"
          },
          "remote": {
            "remote-pad-entry-name": "remote-1"
          },
          "ietf-i2nsf-ike:spd": {
          "spd-entry": [
            {
              "name": "protect-policy-1",
              "ipsec-policy-config": {
                "traffic-selector": {
                  "local-prefix": "192.0.2.0/16",
                  "remote-prefix": "198.51.100.0/16"
                },
                "processing-info": {
                  "action": "protect",
                  "ipsec-sa-cfg": {
                    "ietf-ipsec-iptfs:traffic-flow-security": {
                      "congestion-control": true,
                      "l2-fixed-rate": "1000000000",
                      "packet-size": {
                        "use-path-mtu-discovery": true
                      },
                      "max-aggregation-time": "0.1",
                      "window-size": 1,
                      "send-immediately": false,
                      "lost-packet-timer-interval": "0.2"
                    }
                  }
                }
              }
            }
          ]
        }
      }
    ]
  }
}
Figure 3: Example IP-TFS JSON configuration

A.4. Example JSON Operational Data

This example illustrates operational data for IP-TFS in the IKE case. Note that since this augments the IPsec IKE tree only minimal IKE configuration to satisfy the schema has been populated.

{
  "ietf-i2nsf-ike:ipsec-ike": {
    "ietf-i2nsf-ike:conn-entry": [
      {
        "name": "my-peer-connection",
        "ike-sa-encr-alg": [
        {
          "id": 1,
          "algorithm-type": 12,
          "key-length": 128
        }
        ],
        "local": {
          "local-pad-entry-name": "local-1"
        },
        "remote": {
          "remote-pad-entry-name": "remote-1"
        },
        "ietf-i2nsf-ike:child-sa-info": {
          "ietf-ipsec-iptfs:traffic-flow-security": {
            "congestion-control": true,
            "l2-fixed-rate": "1000000000",
            "packet-size": {
              "use-path-mtu-discovery": true
            },
            "max-aggregation-time": "0.1",
            "window-size": 5,
            "send-immediately": false,
            "lost-packet-timer-interval": "0.2"
          }
        }
      }
    ]
  }
}
Figure 4: Example IP-TFS JSON Operational data

A.5. Example JSON Operational Statistics

This example shows the JSON formatted statistics for IP-TFS. Note a unidirectional IP-TFS transmit side is illustrated, with arbitrary numbers for transmit.

{
  "ietf-i2nsf-ikeless:ipsec-ikeless": {
    "sad": {
      "sad-entry": [
        {
          "name": "sad-1",
          "ipsec-sa-config": {
            "spi": 1,
            "traffic-selector": {
              "local-prefix": "192.0.2.1/16",
              "remote-prefix": "198.51.100.0/16"
            }
          },
          "ietf-ipsec-iptfs:traffic-flow-security": {
            "window-size": 5,
            "send-immediately": false,
            "lost-packet-timer-interval": "0.2"
          },
          "ietf-ipsec-iptfs:ipsec-stats": {
            "tx-pkts": "300",
            "tx-octets": "80000",
            "tx-drop-pkts": "2",
            "rx-pkts": "0",
            "rx-octets": "0",
            "rx-drop-pkts": "0"
          },
          "ietf-ipsec-iptfs:iptfs-inner-pkt-stats": {
            "tx-pkts": "250",
            "tx-octets": "75000",
            "rx-pkts": "0",
            "rx-octets": "0",
            "rx-incomplete-pkts": "0"
          },
          "ietf-ipsec-iptfs:iptfs-outer-pkt-stats": {
            "tx-all-pad-pkts": "40",
            "tx-all-pad-octets": "40000",
            "tx-extra-pad-pkts": "200",
            "tx-extra-pad-octets": "30000",
            "rx-all-pad-pkts": "0",
            "rx-all-pad-octets": "0",
            "rx-extra-pad-pkts": "0",
            "rx-extra-pad-octets": "0",
            "rx-errored-pkts": "0",
            "rx-missed-pkts": "0"
          },
          "ipsec-sa-state": {
            "sa-lifetime-current": {
              "time": 80000,
              "bytes": "400606",
              "packets": 1000,
              "idle": 5
            }
          }
        }
      ]
    }
  }
}
Figure 5: Example IP-TFS JSON Statistics

Authors' Addresses

Don Fedyk
LabN Consulting, L.L.C.
Christian Hopps
LabN Consulting, L.L.C.