NETMOD WG                                                  D. BogdanovicInternet-Draft                                            Volta NetworksIntended status: Standards Track                         M. JethanandaniExpires: December 17, 2017                            Cisco Systems, Inc                                                                L. Huang                                                        General Electric                                                              S. Agarwal                                                     Cisco Systems, Inc.                                                                D. Blair                                                      Cisco Systems, INc                                                           June 15, 2017           Network Access Control List (ACL) YANG Data Model                     draft-ietf-netmod-acl-model-11Abstract   This document describes a data model of Access Control List (ACL)   basic building blocks.   Editorial Note (To be removed by RFC Editor)   This draft contains many placeholder values that need to be replaced   with finalized values at the time of publication.  This note   summarizes all of the substitutions that are needed.  Please note   that no other RFC Editor instructions are specified anywhere else in   this document.   Artwork in this document contains shorthand references to drafts in   progress.  Please apply the following replacements   o  "XXXX" --> the assigned RFC value for this draft.   o  Revision date in model (Oct 12, 2016) needs to get updated with      the date the draft gets approved.  The date also needs to get      reflected on the line with <CODE BEGINS>.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 http://datatracker.ietf.org/drafts/current/.Bogdanovic, et al.      Expires December 17, 2017               [Page 1]Internet-Draft               ACL YANG model                    June 2017   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 December 17, 2017.Copyright Notice   Copyright (c) 2017 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   (http://trustee.ietf.org/license-info) in effect on the date of   publication of this document.  Please review these documents   carefully, as they describe your rights and restrictions with respect   to this document.  Code Components extracted from this document must   include Simplified BSD License text as described in Section 4.e of   the Trust Legal Provisions and are provided without warranty as   described in the Simplified BSD License.Table of Contents   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3     1.1.  Definitions and Acronyms  . . . . . . . . . . . . . . . .   3   2.  Problem Statement . . . . . . . . . . . . . . . . . . . . . .   4   3.  Understanding ACL's Filters and Actions . . . . . . . . . . .   4     3.1.  ACL Modules . . . . . . . . . . . . . . . . . . . . . . .   5   4.  ACL YANG Models . . . . . . . . . . . . . . . . . . . . . . .   9     4.1.  IETF Access Control List module . . . . . . . . . . . . .   9     4.2.  IETF Packet Fields module . . . . . . . . . . . . . . . .  18     4.3.  An ACL Example  . . . . . . . . . . . . . . . . . . . . .  28     4.4.  Port Range Usage Example  . . . . . . . . . . . . . . . .  28   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  29   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  30   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  30   8.  Open Issues . . . . . . . . . . . . . . . . . . . . . . . . .  31   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  31     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  31     9.2.  Informative References  . . . . . . . . . . . . . . . . .  32   Appendix A.  Extending ACL model examples . . . . . . . . . . . .  32     A.1.  Example of extending existing model for route filtering .  32     A.2.  A company proprietary module example  . . . . . . . . . .  34     A.3.  Example to augment model with mixed ACL type  . . . . . .  42     A.4.  Linux nftables  . . . . . . . . . . . . . . . . . . . . .  43   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  44Bogdanovic, et al.      Expires December 17, 2017               [Page 2]Internet-Draft               ACL YANG model                    June 20171.  Introduction   Access Control List (ACL) is one of the basic elements to configure   device forwarding behavior.  It is used in many networking concepts   such as Policy Based Routing, Firewalls etc.   An ACL is an ordered set of rules that is used to filter traffic on a   networking device.  Each rule is represented by an Access Control   Entry (ACE).   Each ACE has a group of match criteria and a group of action   criteria.   The match criteria consist of a tuple of packet header match criteria   and can have metadata match criteria as well.   o  Packet header matches apply to fields visible in the packet such      as address or class of service or port numbers.   o  In case vendor supports it, metadata matches apply to fields      associated with the packet but not in the packet header such as      input interface or overall packet length   The actions specify what to do with the packet when the matching   criteria is met.  These actions are any operations that would apply   to the packet, such as counting, policing, or simply forwarding.The   list of potential actions is endless depending on the innovations of   the networked devices.   Access Control List is also widely knowns as ACL (pronounce as [ak-uh   l]) or Access List.  In this document, Access Control List, ACL and   Access List are used interchangeably.   The matching of filters and actions in an ACE/ACL are triggered only   after application/attachment of the ACL to an interface, VRF, vty/tty   session, QoS policy, routing protocols amongst various other config   attachment points.  Once attached, it is used for filtering traffic   using the match criteria in the ACE's and taking appropriate   action(s) that have been configured against that ACE.  In order to   apply an ACL to any attachment point, vendors would have to augment   the ACL YANG model.1.1.  Definitions and Acronyms   ACE: Access Control Entry   ACL: Access Control ListBogdanovic, et al.      Expires December 17, 2017               [Page 3]Internet-Draft               ACL YANG model                    June 2017   DSCP: Differentiated Services Code Point   ICMP: Internet Control Message Protocol   IP: Internet Protocol   IPv4: Internet Protocol version 4   IPv6: Internet Protocol version 6   MAC: Media Access Control   TCP: Transmission Control Protocol2.  Problem Statement   This document defines a YANG [RFC6020] data model for the   configuration of ACLs.  It is very important that model can be easily   used by applications/attachments.   ACL implementations in every device may vary greatly in terms of the   filter constructs and actions that they support.  Therefore this   draft proposes a model that can be augmented by standard extensions   and vendor proprietary models.3.  Understanding ACL's Filters and Actions   Although different vendors have different ACL data models, there is a   common understanding of what access control list (ACL) is.  A network   system usually have a list of ACLs, and each ACL contains an ordered   list of rules, also known as access list entries - ACEs.  Each ACE   has a group of match criteria and a group of action criteria.  The   match criteria consist of packet header matching.  It as also   possible for ACE to match on metadata, if supported by the vendor.   Packet header matching applies to fields visible in the packet such   as address or class of service or port numbers.  Metadata matching   applies to fields associated with the packet, but not in the packet   header such as input interface, packet length, or source or   destination prefix length.  The actions can be any sort of operation   from logging to rate limiting or dropping to simply forwarding.   Actions on the first matching ACE are applied with no processing of   subsequent ACEs.   The model also includes a container to hold overall operational state   for each ACL and operational state for each ACE.  One ACL can be   applied to multiple targets within the device, such as interfaces of   a networked device, applications or features running in the device,   etc.  When applied to interfaces of a networked device, the ACL isBogdanovic, et al.      Expires December 17, 2017               [Page 4]Internet-Draft               ACL YANG model                    June 2017   applied in a direction which indicates if it should be applied to   packet entering (input) or leaving the device (output).  An example   in the appendix shows how to express it in YANG model.   This draft tries to address the commonalities between all vendors and   create a common model, which can be augmented with proprietary   models.  The base model is simple and with this design we hope to   achieve enough flexibility for each vendor to extend the base model.   The use of feature statements in the document allows vendors to   advertise match rules they support.3.1.  ACL Modules   There are two YANG modules in the model.  The first module, "ietf-   access-control-list", defines generic ACL aspects which are common to   all ACLs regardless of their type or vendor.  In effect, the module   can be viewed as providing a generic ACL "superclass".  It imports   the second module, "ietf-packet-fields".  The match container in   "ietf-access-control-list" uses groupings in "ietf-packet-fields".   The combination of if-feature checks and must statements allow for   the selection of relevant match fields that a user can define rules   for.   If there is a need to define new "matches" choice, such as IPFIX   [RFC5101], the container "matches" can be augmented.   For a reference to the annotations used in the diagram below, see   YANG Tree Diagrams [I-D.ietf-netmod-yang-tree-diagrams]. module: ietf-access-control-list     +--rw access-lists        +--rw acl* [acl-type acl-name]           +--rw acl-name               string           +--rw acl-type               acl-type           +--ro acl-oper-data           +--rw access-list-entries              +--rw ace* [rule-name]                 +--rw rule-name        string                 +--rw matches                 |  +--rw l2-acl {l2-acl}?                 |  |  +--rw destination-mac-address?        yang:mac-ad dress                 |  |  +--rw destination-mac-address-mask?   yang:mac-ad dress                 |  |  +--rw source-mac-address?             yang:mac-ad dress                 |  |  +--rw source-mac-address-mask?        yang:mac-ad dressBogdanovic, et al.      Expires December 17, 2017               [Page 5]Internet-Draft               ACL YANG model                    June 2017                 |  |  +--rw ether-type?                     string                 |  +--rw ipv4-acl {ipv4-acl}?                 |  |  +--rw tos?                        uint8                 |  |  +--rw length?                     uint16                 |  |  +--rw ttl?                        uint8                 |  |  +--rw protocol?                   uint8                 |  |  +--rw source-port-range!                 |  |  |  +--rw lower-port    inet:port-number                 |  |  |  +--rw upper-port?   inet:port-number                 |  |  +--rw destination-port-range!                 |  |  |  +--rw lower-port    inet:port-number                 |  |  |  +--rw upper-port?   inet:port-number                 |  |  +--rw ihl?                        uint8                 |  |  +--rw flags?                      bits                 |  |  +--rw offset?                     uint16                 |  |  +--rw identification?             uint16                 |  |  +--rw destination-ipv4-network?   inet:ipv4-prefi x                 |  |  +--rw source-ipv4-network?        inet:ipv4-prefi x                 |  +--rw ipv6-acl {ipv6-acl}?                 |  |  +--rw tos?                        uint8                 |  |  +--rw length?                     uint16                 |  |  +--rw ttl?                        uint8                 |  |  +--rw protocol?                   uint8                 |  |  +--rw source-port-range!                 |  |  |  +--rw lower-port    inet:port-number                 |  |  |  +--rw upper-port?   inet:port-number                 |  |  +--rw destination-port-range!                 |  |  |  +--rw lower-port    inet:port-number                 |  |  |  +--rw upper-port?   inet:port-number                 |  |  +--rw next-header?                uint8                 |  |  +--rw destination-ipv6-network?   inet:ipv6-prefi x                 |  |  +--rw source-ipv6-network?        inet:ipv6-prefi x                 |  |  +--rw flow-label?                 inet:ipv6-flow- label                 |  +--rw l2-l3-ipv4-acl {mixed-ipv4-acl}?                 |  |  +--rw destination-mac-address?        yang:mac-ad dress                 |  |  +--rw destination-mac-address-mask?   yang:mac-ad dress                 |  |  +--rw source-mac-address?             yang:mac-ad dress                 |  |  +--rw source-mac-address-mask?        yang:mac-ad dress                 |  |  +--rw ether-type?                     stringBogdanovic, et al.      Expires December 17, 2017               [Page 6]Internet-Draft               ACL YANG model                    June 2017                 |  |  +--rw tos?                            uint8                 |  |  +--rw length?                         uint16                 |  |  +--rw ttl?                            uint8                 |  |  +--rw protocol?                       uint8                 |  |  +--rw source-port-range!                 |  |  |  +--rw lower-port    inet:port-number                 |  |  |  +--rw upper-port?   inet:port-number                 |  |  +--rw destination-port-range!                 |  |  |  +--rw lower-port    inet:port-number                 |  |  |  +--rw upper-port?   inet:port-number                 |  |  +--rw ihl?                            uint8                 |  |  +--rw flags?                          bits                 |  |  +--rw offset?                         uint16                 |  |  +--rw identification?                 uint16                 |  |  +--rw destination-ipv4-network?       inet:ipv4-p refix                 |  |  +--rw source-ipv4-network?            inet:ipv4-p refix                 |  +--rw l2-l3-ipv6-acl {mixed-ipv6-acl}?                 |  |  +--rw destination-mac-address?        yang:mac-ad dress                 |  |  +--rw destination-mac-address-mask?   yang:mac-ad dress                 |  |  +--rw source-mac-address?             yang:mac-ad dress                 |  |  +--rw source-mac-address-mask?        yang:mac-ad dress                 |  |  +--rw ether-type?                     string                 |  |  +--rw tos?                            uint8                 |  |  +--rw length?                         uint16                 |  |  +--rw ttl?                            uint8                 |  |  +--rw protocol?                       uint8                 |  |  +--rw source-port-range!                 |  |  |  +--rw lower-port    inet:port-number                 |  |  |  +--rw upper-port?   inet:port-number                 |  |  +--rw destination-port-range!                 |  |  |  +--rw lower-port    inet:port-number                 |  |  |  +--rw upper-port?   inet:port-number                 |  |  +--rw next-header?                    uint8                 |  |  +--rw destination-ipv6-network?       inet:ipv6-p refix                 |  |  +--rw source-ipv6-network?            inet:ipv6-p refix                 |  |  +--rw flow-label?                     inet:ipv6-f low-label                 |  +--rw l2-l3-ipv4-ipv6-acl {l2-l3-ipv4-ipv6-acl}?                 |  |  +--rw destination-mac-address?        yang:mac-ad dressBogdanovic, et al.      Expires December 17, 2017               [Page 7]Internet-Draft               ACL YANG model                    June 2017                 |  |  +--rw destination-mac-address-mask?   yang:mac-ad dress                 |  |  +--rw source-mac-address?             yang:mac-ad dress                 |  |  +--rw source-mac-address-mask?        yang:mac-ad dress                 |  |  +--rw ether-type?                     string                 |  |  +--rw tos?                            uint8                 |  |  +--rw length?                         uint16                 |  |  +--rw ttl?                            uint8                 |  |  +--rw protocol?                       uint8                 |  |  +--rw source-port-range!                 |  |  |  +--rw lower-port    inet:port-number                 |  |  |  +--rw upper-port?   inet:port-number                 |  |  +--rw destination-port-range!                 |  |  |  +--rw lower-port    inet:port-number                 |  |  |  +--rw upper-port?   inet:port-number                 |  |  +--rw ihl?                            uint8                 |  |  +--rw flags?                          bits                 |  |  +--rw offset?                         uint16                 |  |  +--rw identification?                 uint16                 |  |  +--rw destination-ipv4-network?       inet:ipv4-p refix                 |  |  +--rw source-ipv4-network?            inet:ipv4-p refix                 |  |  +--rw next-header?                    uint8                 |  |  +--rw destination-ipv6-network?       inet:ipv6-p refix                 |  |  +--rw source-ipv6-network?            inet:ipv6-p refix                 |  |  +--rw flow-label?                     inet:ipv6-f low-label                 |  +--rw tcp-acl {tcp-acl}?                 |  |  +--rw sequence-number?          uint32                 |  |  +--rw acknowledgement-number?   uint32                 |  |  +--rw data-offset?              uint8                 |  |  +--rw reserved?                 uint8                 |  |  +--rw flags?                    uint16                 |  |  +--rw window-size?              uint16                 |  |  +--rw urgent-pointer?           uint16                 |  |  +--rw options?                  uint32                 |  +--rw udp-acl {udp-acl}?                 |  |  +--rw length?   uint16                 |  +--rw icmp-acl {icmp-acl}?                 |  |  +--rw type?             uint8                 |  |  +--rw code?             uint8                 |  |  +--rw rest-of-header?   uint32                 |  +--rw any-acl! {any-acl}?Bogdanovic, et al.      Expires December 17, 2017               [Page 8]Internet-Draft               ACL YANG model                    June 2017                 +--rw actions                 |  +--rw (packet-handling)?                 |  |  +--:(deny)                 |  |  |  +--rw deny?      empty                 |  |  +--:(permit)                 |  |     +--rw permit?    empty                 |  +--rw logging?   boolean                 +--ro ace-oper-data                    +--ro match-counter?   yang:counter644.  ACL YANG Models4.1.  IETF Access Control List module   "ietf-access-control-list" is the standard top level module for   access lists.  The "access-lists" container stores a list of "acl".   Each "acl" has information identifying the access list by a   name("acl-name") and a list("access-list-entries") of rules   associated with the "acl-name".  Each of the entries in the   list("access-list-entries"), indexed by the string "rule-name", has   containers defining "matches" and "actions".   The "matches" define criteria used to identify patterns in "ietf-   packet-fields".  The "actions" define behavior to undertake once a   "match" has been identified.  In addition to permit and deny for   actions, a logging option allows for a match to be logged that can be   used to determine which rule was matched upon.<CODE BEGINS> file "ietf-access-control-list@2017-06-16.yang"module ietf-access-control-list {  namespace "urn:ietf:params:xml:ns:yang:ietf-access-control-list";  prefix acl;  import ietf-yang-types {    prefix yang;  }  import ietf-packet-fields {    prefix packet-fields;  }  organization    "IETF NETMOD (NETCONF Data Modeling Language)     Working Group";  contact    "WG Web: http://tools.ietf.org/wg/netmod/     WG List: netmod@ietf.org     Editor: Dean Bogdanovic     ivandean@gmail.comBogdanovic, et al.      Expires December 17, 2017               [Page 9]Internet-Draft               ACL YANG model                    June 2017     Editor: Mahesh Jethanandani     mjethanandani@gmail.com     Editor: Lisa Huang     lyihuang16@gmail.com     Editor: Sonal Agarwal     agarwaso@cisco.com     Editor: Dana Blair     dblair@cisco.com";  description    "This YANG module defines a component that describing the     configuration of Access Control Lists (ACLs).     Copyright (c) 2016 IETF Trust and the persons identified as     the document authors.  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     (http://trustee.ietf.org/license-info).     This version of this YANG module is part of RFC XXXX; see     the RFC itself for full legal notices.";  revision 2017-06-16 {    description      "Added feature and identity statements for different types       of rule matches. Split the matching rules based on the       feature statement and added a must statement within       each container.";    reference      "RFC XXX: Network Access Control List (ACL) YANG Data Model.";  }  revision 2016-10-12 {    description      "Base model for Network Access Control List (ACL).";    reference      "RFC XXXX: Network Access Control List (ACL)      YANG Data  Model";  }  /*   * Identities   */  identity acl-base {    description      "Base Access Control List type for all Access Control List type      identifiers.";Bogdanovic, et al.      Expires December 17, 2017              [Page 10]Internet-Draft               ACL YANG model                    June 2017  }  identity ipv4-acl {    base acl:acl-base;    description       "ACL that primarily matches on fields from the IPv4 header       (e.g. IPv4 destination address) and layer 4 headers (e.g. TCP       destination port).  An acl of type ipv4-acl does not contain       matches on fields in the ethernet header or the IPv6 header.";  }  identity ipv6-acl {    base acl:acl-base;    description      "ACL that primarily matches on fields from the IPv6 header      (e.g. IPv6 destination address) and layer 4 headers (e.g. TCP      destination port). An acl of type ipv6-acl does not contain      matches on fields in the ethernet header or the IPv4 header.";  }  identity eth-acl {    base acl:acl-base;    description      "ACL that primarily matches on fields in the ethernet header,      like 10/100/1000baseT or WiFi Access Control List. An acl of      type eth-acl does not contain matches on fields in the IPv4      header, IPv6 header or layer 4 headers.";  }  identity mixed-l2-l3-ipv4-acl {    base "acl:acl-base";    description      "ACL that contains a mix of entries that       primarily match on fields in ethernet headers,       entries that primarily match on IPv4 headers.       Matching on layer 4 header fields may also exist in the       list.";  }  identity mixed-l2-l3-ipv6-acl {    base "acl:acl-base";    description      "ACL that contains a mix of entries that       primarily match on fields in ethernet headers, entries       that primarily match on fields in IPv6 headers. Matching on       layer 4 header fields may also exist in the list.";Bogdanovic, et al.      Expires December 17, 2017              [Page 11]Internet-Draft               ACL YANG model                    June 2017  }  identity mixed-l2-l3-ipv4-ipv6-acl {    base "acl:acl-base";    description      "ACL that contains a mix of entries that       primarily match on fields in ethernet headers, entries       that primarily match on fields in IPv4 headers, and entries       that primarily match on fields in IPv6 headers. Matching on       layer 4 header fields may also exist in the list.";  }  identity any-acl {    base "acl:acl-base";    description      "ACL that can contain any pattern to match upon";  }  /*   * Features   */  feature l2-acl {    description      "Layer 2 ACL supported";  }  feature ipv4-acl {    description      "Layer 3 IPv4 ACL supported";  }  feature ipv6-acl {    description      "Layer 3 IPv6 ACL supported";  }  feature mixed-ipv4-acl {    description      "Layer 2 and Layer 3 IPv4 ACL supported";  }  feature mixed-ipv6-acl {    description      "Layer 2 and Layer 3 IPv6 ACL supported";  }Bogdanovic, et al.      Expires December 17, 2017              [Page 12]Internet-Draft               ACL YANG model                    June 2017  feature l2-l3-ipv4-ipv6-acl {    description      "Layer 2 and any Layer 3 ACL supported.";  }  feature tcp-acl {    description      "TCP header ACL supported.";  }  feature udp-acl {    description      "UDP header ACL supported.";  }  feature icmp-acl {    description      "ICMP header ACL supported.";  }  feature any-acl {    description     "ACL for any pattern.";  }  /*   * Typedefs   */  typedef acl-type {    type identityref {      base acl-base;    }    description      "This type is used to refer to an Access Control List      (ACL) type";  }  typedef access-control-list-ref {    type leafref {      path "/access-lists/acl/acl-name";    }    description      "This type is used by data models that need to reference an      Access Control List";  }  /*   * Configuration data nodesBogdanovic, et al.      Expires December 17, 2017              [Page 13]Internet-Draft               ACL YANG model                    June 2017   */  container access-lists {    description      "This is a top level container for Access Control Lists.       It can have one or more Access Control Lists.";    list acl {      key "acl-type acl-name";      description        "An Access Control List(ACL) is an ordered list of         Access List Entries (ACE). Each Access Control Entry has a         list of match criteria and a list of actions.         Since there are several kinds of Access Control Lists         implemented with different attributes for         different vendors, this         model accommodates customizing Access Control Lists for         each kind and for each vendor.";      leaf acl-name {        type string;        description          "The name of access-list. A device MAY restrict the length           and value of this name, possibly space and special           characters are not allowed.";      }      leaf acl-type {        type acl-type;        description          "Type of access control list. Indicates the primary intended           type of match criteria (e.g. ethernet, IPv4, IPv6, mixed,           etc) used in the list instance.";      }      container acl-oper-data {        config false;        description          "Overall Access Control List operational data";      }      container access-list-entries {        description          "The access-list-entries container contains           a list of access-list-entries(ACE).";        list ace {          key "rule-name";          ordered-by user;          description            "List of access list entries(ACE)";          leaf rule-name {            type string;            description              "A unique name identifying this Access ListBogdanovic, et al.      Expires December 17, 2017              [Page 14]Internet-Draft               ACL YANG model                    June 2017               Entry(ACE).";          }          container matches {            description              "The rules in this set determine what fields will be               matched upon before any action is taken on them.               The rules are selected based on the feature set               defined by the server and the acl-type defined.";            container l2-acl {              if-feature l2-acl;              must "../../../../acl-type = 'eth-acl'";              uses packet-fields:acl-eth-header-fields;              description                "Rule set for L2 ACL.";            }            container ipv4-acl {              if-feature ipv4-acl;                  must "../../../../acl-type = 'ipv4-acl'";              uses packet-fields:acl-ip-header-fields;                  uses packet-fields:acl-ipv4-header-fields;              description                "Rule set that supports IPv4 headers.";            }            container ipv6-acl {              if-feature ipv6-acl;              must "../../../../acl-type = 'ipv6-acl'";              uses packet-fields:acl-ip-header-fields;              uses packet-fields:acl-ipv6-header-fields;              description                "Rule set that supports IPv6 headers.";            }            container l2-l3-ipv4-acl {              if-feature mixed-ipv4-acl;              must "../../../../acl-type = 'mixed-l2-l3-ipv4-acl'";              uses packet-fields:acl-eth-header-fields;              uses packet-fields:acl-ip-header-fields;              uses packet-fields:acl-ipv4-header-fields;              description                "Rule set that is a logical AND (&&) of l2                 and ipv4 headers.";            }            container l2-l3-ipv6-acl {Bogdanovic, et al.      Expires December 17, 2017              [Page 15]Internet-Draft               ACL YANG model                    June 2017              if-feature mixed-ipv6-acl;              must "../../../../acl-type = 'mixed-l2-l3-ipv6-acl'";              uses packet-fields:acl-eth-header-fields;              uses packet-fields:acl-ip-header-fields;              uses packet-fields:acl-ipv6-header-fields;              description                "Rule set that is a logical AND (&&) of L2                 && IPv6 headers.";            }            container l2-l3-ipv4-ipv6-acl {              if-feature l2-l3-ipv4-ipv6-acl;              must "../../../../acl-type = 'mixed-l2-l3-ipv4-ipv6-acl'";              uses packet-fields:acl-eth-header-fields;              uses packet-fields:acl-ip-header-fields;              uses packet-fields:acl-ipv4-header-fields;              uses packet-fields:acl-ipv6-header-fields;              description                "Rule set that is a logical AND (&&) of L2                 && IPv4 && IPv6 headers.";            }            container tcp-acl {              if-feature tcp-acl;              uses packet-fields:acl-tcp-header-fields;              description                "Rule set that defines TCP headers.";            }            container udp-acl {              if-feature udp-acl;              uses packet-fields:acl-udp-header-fields;              description                "Rule set that defines UDP headers.";            }            container icmp-acl {              if-feature icmp-acl;              uses packet-fields:acl-icmp-header-fields;              description                "Rule set that defines ICMP headers.";            }            container any-acl {              if-feature any-acl;              must "../../../../acl-type = 'any-acl'";              presence "Matches any";              descriptionBogdanovic, et al.      Expires December 17, 2017              [Page 16]Internet-Draft               ACL YANG model                    June 2017                "Rule set that allows for a any ACL.";            }          }          container actions {            description              "Definitions of action criteria for this Access List               Entry.";            choice packet-handling {              default "deny";              description                "Packet handling action.";              case deny {                leaf deny {                  type empty;                  description                    "Deny action.";                }              }              case permit {                leaf permit {                  type empty;                  description                    "Permit action.";                }              }            }            leaf logging {              type boolean;              description                "Log the rule on which the match occurred.                 Setting the value to true enables logging,                 whereas setting the value to false disables it.";            }          }          /*           * Operational state data nodes           */          container ace-oper-data {            config false;            description              "Operational data for this Access List Entry.";            leaf match-counter {              type yang:counter64;              description                "Number of matches for this Access List Entry";            }          }Bogdanovic, et al.      Expires December 17, 2017              [Page 17]Internet-Draft               ACL YANG model                    June 2017        }      }    }  }}<CODE ENDS>4.2.  IETF Packet Fields module   The packet fields module defines the necessary groups for matching on   fields in the packet including ethernet, ipv4, ipv6, and transport   layer fields.  The 'acl-type' node determines which of these fields   get included for any given ACL with the exception of TCP, UDP and   ICMP header fields.  Those fields can be used in conjunction with any   of the above layer 2 or layer 3 fields.   Since the number of match criteria is very large, the base draft does   not include these directly but references them by "uses" to keep the   base module simple.  In case more match conditions are needed, those   can be added by augmenting choices within container "matches" in   ietf-access-control-list.yang model.<CODE BEGINS> file "ietf-packet-fields@2017-06-16.yang"module ietf-packet-fields {  namespace "urn:ietf:params:xml:ns:yang:ietf-packet-fields";  prefix packet-fields;  import ietf-inet-types {    prefix inet;  }  import ietf-yang-types {    prefix yang;  }  organization    "IETF NETMOD (NETCONF Data Modeling Language) Working     Group";  contact    "WG Web: http://tools.ietf.org/wg/netmod/    WG List: netmod@ietf.org    Editor: Dean Bogdanovic    ivandean@gmail.com    Editor: Mahesh JethanandaniBogdanovic, et al.      Expires December 17, 2017              [Page 18]Internet-Draft               ACL YANG model                    June 2017    mahesh@cisco.com    Editor: Lisa Huang    lyihuang16@gmail.com    Editor: Sonal Agarwal    agarwaso@cisco.com    Editor: Dana Blair    dblair@cisco.com";  description    "This YANG module defines groupings that are used by    ietf-access-control-list YANG module. Their usage is not    limited to ietf-access-control-list and can be    used anywhere as applicable.    Copyright (c) 2016 IETF Trust and the persons identified as    the document authors.  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    (http://trustee.ietf.org/license-info).    This version of this YANG module is part of RFC XXXX; see    the RFC itself for full legal notices.";  revision 2017-06-16 {    description      "Added header fields for TCP, UDP, and ICMP.";    reference      "RFC XXX: Network Access Control List (ACL) YANG Data Model.";  }  revision 2016-10-12 {    description      "Initial version of packet fields used by       ietf-access-control-list";    reference      "RFC XXXX: Network Access Control List (ACL)       YANG Data  Model";  }  grouping acl-transport-header-fields {    description      "Transport header fields";    container source-port-range {      presence "Enables setting source port range";      description        "Inclusive range representing source ports to be used.Bogdanovic, et al.      Expires December 17, 2017              [Page 19]Internet-Draft               ACL YANG model                    June 2017         When only lower-port is present, it represents a single port.";      leaf lower-port {        type inet:port-number;        mandatory true;        description          "Lower boundary for port.";      }      leaf upper-port {        type inet:port-number;        must ". >= ../lower-port" {          error-message          "The upper-port must be greater than or equal           to lower-port";        }        description          "Upper boundary for port . If existing, the upper port           must be greater or equal to lower-port.";      }    }    container destination-port-range {      presence "Enables setting destination port range";      description        "Inclusive range representing destination ports to be used.         When only lower-port is present, it represents a single         port.";      leaf lower-port {        type inet:port-number;        mandatory true;        description          "Lower boundary for port.";      }      leaf upper-port {        type inet:port-number;        must ". >= ../lower-port" {          error-message            "The upper-port must be greater than or equal             to lower-port";        }        description          "Upper boundary for port. If existing, the upper port must          be greater or equal to lower-port";      }    }  }Bogdanovic, et al.      Expires December 17, 2017              [Page 20]Internet-Draft               ACL YANG model                    June 2017  grouping acl-ip-header-fields {    description      "IP header fields common to ipv4 and ipv6";    reference      "RFC 791.";    leaf tos {      type uint8;      description        "Also known as Traffic Class in IPv6. The Type of Service (TOS)         provides an indication of the abstract parameters of the         quality of service desired.";      reference        "RFC 719, RFC 2460";    }    leaf length {      type uint16;      description        "In IPv4 header field, this field is known as the Total Length.         Total Length is the length of the datagram, measured in octets,         including internet header and data.         In IPv6 header field, this field is known as the Payload         Length, the length of the IPv6 payload, i.e. the rest of         the packet following the IPv6 header, in octets.";      reference        "RFC 719, RFC 2460";    }    leaf ttl {      type uint8;      description        "This field indicates the maximum time the datagram is allowed         to remain in the internet system.  If this field contains the         value zero, then the datagram must be destroyed.         In IPv6, this field is known as the Hop Limit.";      reference "RFC 719, RFC 2460";    }    leaf protocol {      type uint8;      description        "Internet Protocol number.";    }    uses acl-transport-header-fields;  }Bogdanovic, et al.      Expires December 17, 2017              [Page 21]Internet-Draft               ACL YANG model                    June 2017  grouping acl-ipv4-header-fields {    description      "Fields in IPv4 header.";    leaf ihl {      type uint8 {        range "5..60";      }      description        "An IPv4 header field, the Internet Header Length (IHL) is         the length of the internet header in 32 bit words, and         thus points to the beginning of the data. Note that the         minimum value for a correct header is 5.";    }    leaf flags {      type bits {        bit reserved {          position 0;          description            "Reserved. Must be zero.";        }        bit fragment {          position 1;          description            "Setting value to 0 indicates may fragment, while setting             the value to 1 indicates do not fragment.";        }        bit more {          position 2;          description            "Setting the value to 0 indicates this is the last fragment,             and setting the value to 1 indicates more fragments are             coming.";        }      }      description        "Bit definitions for the flags field in IPv4 header.";    }    leaf offset {      type uint16 {        range "20..65535";      }      description        "The fragment offset is measured in units of 8 octets (64 bits).         The first fragment has offset zero. The length is 13 bits";    }Bogdanovic, et al.      Expires December 17, 2017              [Page 22]Internet-Draft               ACL YANG model                    June 2017    leaf identification {      type uint16;      description        "An identifying value assigned by the sender to aid in         assembling the fragments of a datagram.";    }    leaf destination-ipv4-network {      type inet:ipv4-prefix;      description        "Destination IPv4 address prefix.";    }    leaf source-ipv4-network {      type inet:ipv4-prefix;      description        "Source IPv4 address prefix.";    }  }  grouping acl-ipv6-header-fields {    description      "Fields in IPv6 header";    leaf next-header {      type uint8;      description        "Identifies the type of header immediately following the         IPv6 header. Uses the same values as the IPv4 Protocol         field.";      reference        "RFC 2460";    }    leaf destination-ipv6-network {      type inet:ipv6-prefix;      description        "Destination IPv6 address prefix.";    }    leaf source-ipv6-network {      type inet:ipv6-prefix;      description        "Source IPv6 address prefix.";    }    leaf flow-label {      type inet:ipv6-flow-label;      descriptionBogdanovic, et al.      Expires December 17, 2017              [Page 23]Internet-Draft               ACL YANG model                    June 2017        "IPv6 Flow label.";    }    reference      "RFC 4291: IP Version 6 Addressing Architecture       RFC 4007: IPv6 Scoped Address Architecture       RFC 5952: A Recommendation for IPv6 Address Text                 Representation";  }  grouping acl-eth-header-fields {    description      "Fields in Ethernet header.";    leaf destination-mac-address {      type yang:mac-address;      description        "Destination IEEE 802 MAC address.";    }    leaf destination-mac-address-mask {      type yang:mac-address;      description        "Destination IEEE 802 MAC address mask.";    }    leaf source-mac-address {      type yang:mac-address;      description        "Source IEEE 802 MAC address.";    }    leaf source-mac-address-mask {      type yang:mac-address;      description        "Source IEEE 802 MAC address mask.";    }    leaf ether-type {      type string {        pattern '[0-9a-fA-F]{4}';      }      description        "The Ethernet Type (or Length) value represented         in the canonical order defined by IEEE 802.         The canonical representation uses lowercase         characters.         Note: This is not the most ideal way to define         ether-types. Ether-types are well known types         and are registered with RAC in IEEE. So they         should well defined types with values. For now         this model is defining it as a string.Bogdanovic, et al.      Expires December 17, 2017              [Page 24]Internet-Draft               ACL YANG model                    June 2017         There is a note out to IEEE that needs to be         turned into a liaison statement asking them to         define all ether-types for the industry to use.";      reference        "IEEE 802-2014 Clause 9.2";    }    reference      "IEEE 802: IEEE Standard for Local and Metropolitan       Area Networks: Overview and Architecture.";  }  grouping acl-tcp-header-fields {    description      "Collection of TCP header fields that can be used to       setup a match filter.";    leaf sequence-number {      type uint32;      description        "Sequence number that appears in the packet.";    }    leaf acknowledgement-number {      type uint32;      description        "The acknowledgement number that appears in the         packet.";    }    leaf data-offset {      type uint8 {        range "5..15";      }      description        "Specifies the size of the TCP header in 32-bit         words. The minimum size header is 5 words and         the maximum is 15 words thus giving the minimum         size of 20 bytes and maximum of 60 bytes,         allowing for up to 40 bytes of options in the         header.";    }    leaf reserved {      type uint8;      description        "Reserved for future use.";    }Bogdanovic, et al.      Expires December 17, 2017              [Page 25]Internet-Draft               ACL YANG model                    June 2017    leaf flags {      type uint16;      description        "Also known as Control Bits. Contains 9 1-bit flags.";    }    leaf window-size {      type uint16;      description        "The size of the receive window, which specifies         the number of window size units (by default,         bytes) (beyond the segment identified by the         sequence number in the acknowledgment field)         that the sender of this segment is currently         willing to receive.";    }    leaf urgent-pointer {      type uint16;      description        "This field s an offset from the sequence number         indicating the last urgent data byte.";    }    leaf options {      type uint32;      description        "The length of this field is determined by the         data offset field. Options have up to three         fields: Option-Kind (1 byte), Option-Length         (1 byte), Option-Data (variable). The Option-Kind         field indicates the type of option, and is the         only field that is not optional. Depending on         what kind of option we are dealing with,         the next two fields may be set: the Option-Length         field indicates the total length of the option,         and the Option-Data field contains the value of         the option, if applicable.";    }  }  grouping acl-udp-header-fields {    description      "Collection of UDP header fields that can be used       to setup a match filter.";    leaf length {      type uint16;Bogdanovic, et al.      Expires December 17, 2017              [Page 26]Internet-Draft               ACL YANG model                    June 2017      description        "A field that specifies the length in bytes of         the UDP header and UDP data. The minimum         length is 8 bytes because that is the length of         the header. The field size sets a theoretical         limit of 65,535 bytes (8 byte header + 65,527         bytes of data) for a UDP datagram. However the         actual limit for the data length, which is         imposed by the underlying IPv4 protocol, is         65,507 bytes (65,535 minus 8 byte UDP header         minus 20 byte IP header).         In IPv6 jumbograms it is possible to have         UDP packets of size greater than 65,535 bytes.         RFC 2675 specifies that the length field is set         to zero if the length of the UDP header plus         UDP data is greater than 65,535.";    }  }  grouping acl-icmp-header-fields {    description      "Collection of ICMP header fields that can be       used to setup a match filter.";    leaf type {      type uint8;      description        "Also known as Control messages.";      reference "RFC 792";    }    leaf code {      type uint8;      description        "ICMP subtype. Also known as Control messages.";    }    leaf rest-of-header {      type uint32;      description        "Four-bytes field, contents vary based on the         ICMP type and code.";    }  }}<CODE ENDS>Bogdanovic, et al.      Expires December 17, 2017              [Page 27]Internet-Draft               ACL YANG model                    June 20174.3.  An ACL Example   Requirement: Deny tcp traffic from 10.10.10.1/24, destined to   11.11.11.1/24.   Here is the acl configuration xml for this Access Control List:   <?xml version='1.0' encoding='UTF-8'?>     <data xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">       <access-lists xmlns="urn:ietf:params:xml:ns:yang:        ietf-access-control-list">         <acl>           <acl-name>sample-ipv4-acl</acl-name>           <acl-type>ipv4</acl-type>           <access-list-entries>             <ace>               <rule-name>rule1</rule-name>               <matches>                 <source-ipv4-network>                   10.10.10.1/24                 </source-ipv4-network>                 <destination-ipv4-network>                   11.11.11.1/24                 </destination-ipv4-network>               </matches>               <actions>                 <deny />               </actions>               <protocol>                tcp               </protocol>             </ace>           </access-list-entries>         </acl>       </access-lists>     </data>   The acl and aces can be described in CLI as the following:         access-list ipv4 sample-ipv4-acl         deny tcp 10.10.10.1/24 11.11.11.1/244.4.  Port Range Usage Example   When a lower-port and an upper-port are both present, it represents a   range between lower-port and upper-port with both the lower-port and   upper-port are included.  When only a lower-port presents, it   represents a single port.Bogdanovic, et al.      Expires December 17, 2017              [Page 28]Internet-Draft               ACL YANG model                    June 2017   With the follow XML snippet:        <source-port-range>          <lower-port>16384</lower-port>          <upper-port>16387</upper-port>        </source-port-range>   This represents source ports 16384,16385, 16386, and 16387.   With the follow XML snippet:         <source-port-range>           <lower-port>16384</lower-port>           <upper-port>65535</upper-port>         </source-port-range>   This represents source ports greater than/equal to 16384 and less   than equal to 65535.   With the follow XML snippet:         <source-port-range>           <lower-port>21</lower-port>         </source-port-range>   This represents port 21.5.  Security Considerations   The YANG module defined in this memo is designed to be accessed via   the NETCONF [RFC6241].  The lowest NETCONF layer is the secure   transport layer and the mandatory-to-implement secure transport is   SSH [RFC6242].  The NETCONF Access Control Model ( NACM [RFC6536])   provides the means to restrict access for particular NETCONF users to   a pre-configured subset of all available NETCONF protocol operations   and content.   There are a number of data nodes defined in the YANG module which are   writable/creatable/deletable (i.e., config true, which is the   default).  These data nodes may be considered sensitive or vulnerable   in some network environments.  Write operations (e.g., <edit-config>)   to these data nodes without proper protection can have a negative   effect on network operations.   These are the subtrees and data nodes and their sensitivity/   vulnerability:Bogdanovic, et al.      Expires December 17, 2017              [Page 29]Internet-Draft               ACL YANG model                    June 2017   /access-lists/acl/access-list-entries: This list specifies all the   configured access list entries on the device.  Unauthorized write   access to this list can allow intruders to access and control the   system.  Unauthorized read access to this list can allow intruders to   spoof packets with authorized addresses thereby compromising the   system.6.  IANA Considerations   This document registers a URI in the IETF XML registry [RFC3688].   Following the format in RFC 3688, the following registration is   requested to be made:   URI: urn:ietf:params:xml:ns:yang:ietf-access-control-list   URI: urn:ietf:params:xml:ns:yang:ietf-packet-fields   Registrant Contact: The IESG.   XML: N/A, the requested URI is an XML namespace.   This document registers a YANG module in the YANG Module Names   registry [RFC6020].   name: ietf-access-control-list namespace:   urn:ietf:params:xml:ns:yang:ietf-access-control-list prefix: ietf-acl   reference: RFC XXXX   name: ietf-packet-fields namespace: urn:ietf:params:xml:ns:yang:ietf-   packet-fields prefix: ietf-packet-fields reference: RFC XXXX7.  Acknowledgements   Alex Clemm, Andy Bierman and Lisa Huang started it by sketching out   an initial IETF draft in several past IETF meetings.  That draft   included an ACL YANG model structure and a rich set of match filters,   and acknowledged contributions by Louis Fourie, Dana Blair, Tula   Kraiser, Patrick Gili, George Serpa, Martin Bjorklund, Kent Watsen,   and Phil Shafer.  Many people have reviewed the various earlier   drafts that made the draft went into IETF charter.   Dean Bogdanovic, Kiran Agrahara Sreenivasa, Lisa Huang, and Dana   Blair each evaluated the YANG model in previous draft separately and   then work together, to created a new ACL draft that can be supported   by different vendors.  The new draft removes vendor specific   features, and gives examples to allow vendors to extend in their own   proprietary ACL.  The earlier draft was superseded with the new one   that received more participation from many vendors.Bogdanovic, et al.      Expires December 17, 2017              [Page 30]Internet-Draft               ACL YANG model                    June 2017   Authors would like to thank Jason Sterne, Lada Lhotka, Juergen   Schoenwalder, and David Bannister for their review of and suggestions   to the draft.8.  Open Issues   o  The current model does not support the concept of "containers"      used to contain multiple addresses per rule entry.   o  The current model defines 'any' rule as a presence container,      allowing a user to define any 'any' rule.   o  The model defines 'ether-type' node as a string.  Ideally, this      should be a well defined list of all Ethernet Types assigned by      IEEE.   o  Should this draft include route-policy definition as defined in      draft-ietf-rtgwg-policy-model?9.  References9.1.  Normative References   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,              DOI 10.17487/RFC3688, January 2004,              <http://www.rfc-editor.org/info/rfc3688>.   [RFC6020]  Bjorklund, M., Ed., "YANG - A Data Modeling Language for              the Network Configuration Protocol (NETCONF)", RFC 6020,              DOI 10.17487/RFC6020, October 2010,              <http://www.rfc-editor.org/info/rfc6020>.   [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,              <http://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,              <http://www.rfc-editor.org/info/rfc6242>.   [RFC6536]  Bierman, A. and M. Bjorklund, "Network Configuration              Protocol (NETCONF) Access Control Model", RFC 6536,              DOI 10.17487/RFC6536, March 2012,              <http://www.rfc-editor.org/info/rfc6536>.Bogdanovic, et al.      Expires December 17, 2017              [Page 31]Internet-Draft               ACL YANG model                    June 20179.2.  Informative References   [I-D.ietf-netmod-yang-tree-diagrams]              Bjorklund, M. and L. Berger, "YANG Tree Diagrams", draft-              ietf-netmod-yang-tree-diagrams-00 (work in progress), June              2017.   [RFC5101]  Claise, B., Ed., "Specification of the IP Flow Information              Export (IPFIX) Protocol for the Exchange of IP Traffic              Flow Information", RFC 5101, DOI 10.17487/RFC5101, January              2008, <http://www.rfc-editor.org/info/rfc5101>.Appendix A.  Extending ACL model examplesA.1.  Example of extending existing model for route filtering   With proposed modular design, it is easy to extend the model with   other features.  Those features can be standard features, like route   filters.  Route filters match on specific IP addresses or ranges of   prefixes.  Much like ACLs, they include some match criteria and   corresponding match action(s).  For that reason, it is very simple to   extend existing ACL model with route filtering.  The combination of a   route prefix and prefix length along with the type of match   determines how route filters are evaluated against incoming routes.   Different vendors have different match types and in this model we are   using only ones that are common across all vendors participating in   this draft.  As in this example, the base ACL model can be extended   with company proprietary extensions, described in the next section.   module: example-ext-route-filter   augment /ietf-acl:access-lists/ietf-acl:acl/   ietf-acl:access-list-entries/ietf-acl:ace/ietf-acl:matches:      +--rw (route-prefix)?         +--:(range)            +--rw (ipv4-range)?            |  +--:(v4-lower-bound)            |  |  +--rw v4-lower-bound?   inet:ipv4-prefix            |  +--:(v4-upper-bound)            |     +--rw v4-upper-bound?   inet:ipv4-prefix            +--rw (ipv6-range)?               +--:(v6-lower-bound)               |  +--rw v6-lower-bound?   inet:ipv6-prefix               +--:(v6-upper-bound)                  +--rw v6-upper-bound?   inet:ipv6-prefix   file "example-ext-route-filter@2016-10-12.yang"   module example-ext-route-filter {     namespace "urn:ietf:params:xml:ns:yang:example-ext-route-filter";Bogdanovic, et al.      Expires December 17, 2017              [Page 32]Internet-Draft               ACL YANG model                    June 2017     prefix example-ext-route-filter;     import ietf-inet-types {       prefix "inet";     }     import ietf-access-control-list {       prefix "ietf-acl";     }     organization       "Route model group.";     contact       "abc@abc.com";     description "       This module describes route filter as a collection of       match prefixes. When specifying a match prefix, you       can specify an exact match with a particular route or       a less precise match. You can configure either a       common action that applies to the entire list or an       action associated with each prefix.       ";     revision 2016-10-12 {       description         "Creating Route-Filter extension model based on         ietf-access-control-list model";       reference " ";     }     augment "/ietf-acl:access-lists/ietf-acl:acl/"       + "ietf-acl:access-list-entries/ietf-acl:ace/ietf-acl:matches"{       description "         This module augments the matches container in the ietf-acl         module with route filter specific actions         ";       choice route-prefix{         description "Define route filter match criteria";         case range {           description             "Route falls between the lower prefix/prefix-length             and the upperprefix/prefix-length.";           choice ipv4-range {             description "Defines the IPv4 prefix range";             leaf v4-lower-bound {               type inet:ipv4-prefix;               description                 "Defines the lower IPv4 prefix/prefix length";             }             leaf v4-upper-bound {Bogdanovic, et al.      Expires December 17, 2017              [Page 33]Internet-Draft               ACL YANG model                    June 2017               type inet:ipv4-prefix;               description                 "Defines the upper IPv4 prefix/prefix length";             }           }           choice ipv6-range {             description "Defines the IPv6 prefix/prefix range";             leaf v6-lower-bound {               type inet:ipv6-prefix;               description                 "Defines the lower IPv6 prefix/prefix length";             }             leaf v6-upper-bound {               type inet:ipv6-prefix;               description                 "Defines the upper IPv6 prefix/prefix length";             }           }         }       }     }   }A.2.  A company proprietary module example   Access control list typically does not exist in isolation.  Instead,   they are associated with a certain scope in which they are applied,   for example, an interface of a set of interfaces.  How to attach an   access control list to an interface (or other system artifact) is   outside the scope of this model, as it depends on the specifics of   the system model that is being applied.  However, in general, the   general design pattern will involved adding a data node with a   reference, or set of references, to ACLs that are to be applied to   the interface.  For this purpose, the type definition "access-   control-list-ref" can be used.   Module "example-newco-acl" is an example of company proprietary model   that augments "ietf-acl" module.  It shows how to use 'augment' with   an XPath expression to add additional match criteria, action   criteria, and default actions when no ACE matches found, as well how   to attach an Access Control List to an interface.  All these are   company proprietary extensions or system feature extensions.   "example-newco-acl" is just an example and it is expected from   vendors to create their own proprietary models.   The following figure is the tree structure of example-newco-acl.  In   this example, /ietf-acl:access-lists/ietf-acl:acl/ietf-acl:access-Bogdanovic, et al.      Expires December 17, 2017              [Page 34]Internet-Draft               ACL YANG model                    June 2017   list-entries/ ietf-acl:ace/ietf-acl:matches are augmented with two   new choices, protocol-payload-choice and metadata.  The protocol-   payload-choice uses a grouping with an enumeration of all supported   protocol values.  Metadata matches apply to fields associated with   the packet but not in the packet header such as input interface or   overall packet length.  In other example, /ietf-acl:access-lists/   ietf-acl:acl/ietf-acl:access-list-entries/ ietf-acl:ace/ietf-   acl:actions are augmented with new choice of actions.   module: example-newco-acl   augment /ietf-acl:access-lists/ietf-acl:acl/   ietf-acl:access-list-entries/ietf-acl:ace/ietf-acl:matches:      +--rw vlan-tagged?      uint16      +--rw mpls-unicast?     uint16      +--rw mpls-multicast?   uint16      +--rw ipv4?             uint16      +--rw ipv6?             uint16   augment /ietf-acl:access-lists/ietf-acl:acl/   ietf-acl:access-list-entries/ietf-acl:ace/ietf-acl:matches:      +--rw ipv4-ttl?      uint8      +--rw ipv4-len?      uint16      +--rw ipv4-ihl?      uint8      +--rw ipv4-id?       uint16      +--rw ipv4-flags?    ipv4-flags-type      +--rw ipv4-offset?   uint16   augment /ietf-acl:access-lists/ietf-acl:acl/   ietf-acl:access-list-entries/ietf-acl:ace/ietf-acl:matches:      +--rw (protocol-payload-choice)?      |  +--:(protocol-payload)      |     +--rw protocol-payload* [value-keyword]      |        +--rw value-keyword    enumeration      +--rw (metadata)?         +--:(interface-name)            +--rw interface-name* [input-interface]               +--rw input-interface    ietf-if:interface-ref   augment /ietf-acl:access-lists/ietf-acl:acl/   ietf-acl:access-list-entries/ietf-acl:ace/ietf-acl:actions:      +--rw (action)?         +--:(count)         |  +--rw count?                   string         +--:(policer)         |  +--rw policer?                 string         +--:(hiearchical-policer)            +--rw hierarchitacl-policer?   string   augment /ietf-acl:access-lists/ietf-acl:acl:      +--rw default-actions         +--rw deny?   empty   augment /ietf-if:interfaces/ietf-if:interface:Bogdanovic, et al.      Expires December 17, 2017              [Page 35]Internet-Draft               ACL YANG model                    June 2017      +--rw acl         +--rw acl-name?        ietf-acl:access-control-list-ref         +--ro match-counter?   yang:counter64         +--rw (direction)?            +--:(in)            |  +--rw in?              empty            +--:(out)               +--rw out?             empty   augment /ietf-acl:access-lists/ietf-acl:acl/ietf-acl:acl-oper-data:      +--ro targets         +--ro (interface)?            +--:(interface-name)               +--ro interface-name*   ietf-if:interface-ref   module example-newco-acl {     yang-version 1.1;     namespace "urn:newco:params:xml:ns:yang:example-newco-acl";     prefix example-newco-acl;     import ietf-access-control-list {       prefix "ietf-acl";     }     import ietf-interfaces {       prefix "ietf-if";     }     import ietf-yang-types {       prefix yang;     }     organization       "Newco model group.";     contact       "abc@newco.com";     description       "This YANG module augment IETF ACL Yang.";     revision 2016-10-12{       description         "Creating NewCo proprietary extensions to ietf-acl model";       reference         "RFC XXXX: Network Access Control List (ACL)         YANG Data  Model";Bogdanovic, et al.      Expires December 17, 2017              [Page 36]Internet-Draft               ACL YANG model                    June 2017     }     typedef known-ether-type {       type enumeration {         enum "ipv4" {           value 2048; // 0x0800           description "Internet Protocol version 4 (IPv4)";         }         enum "vlan-tagged" {           value 33024; // 0x8100           description             "VLAN-tagged frame (IEEE 802.1Q) & Shortest Path              Bridging IEEE 802.1aq[4]";         }         enum "ipv6" {           value 34525; // 0x86DD           description "Internet Protocol Version 6 (IPv6)";         }         enum "mpls-unicast" {           value 34887; // 0x8847           description "MPLS unicast";         }         enum "mpls-multicast" {           value 34888; // 0x8848           description "MPLS multicast";         }       }       description "Listing supported Ethertypes";     }     typedef ipv4-flags-type {       type bits {         bit ipv4-reserved {           position 0;           description "reserved bit";         }         bit ipv4-DF {           position 1;           description "DF bit";         }         bit ipv4-MF {          position 2;          description "MF bit";         }       }       description "IPv4 flag types";     }Bogdanovic, et al.      Expires December 17, 2017              [Page 37]Internet-Draft               ACL YANG model                    June 2017     augment "/ietf-acl:access-lists/ietf-acl:acl/" +             "ietf-acl:access-list-entries/ietf-acl:ace/" +             "ietf-acl:matches" {      when "ietf-acl:access-lists/ietf-acl:acl/" +           "ietf-acl:acl-type = 'ace-eth'";      description "additional MAC header matching";        leaf vlan-tagged {          type uint16;          description "Ethernet frame with VLAN tag";        }        leaf mpls-unicast {          type uint16;          description "Ethernet frame with MPLS unicast payload";        }        leaf mpls-multicast {          type uint16;          description "Ethernet frame with MPLS multicast payload";        }        leaf ipv4 {          type uint16;          description "Ethernet frame with IPv4 unicast payload";        }        leaf ipv6 {          type uint16;          description "Ethernet frame with IPv4 unicast payload";        }     }     augment "/ietf-acl:access-lists/ietf-acl:acl/" +             "ietf-acl:access-list-entries/ietf-acl:ace/" +             "ietf-acl:matches" {      when "ietf-acl:access-lists/ietf-acl:acl/" +           "ietf-acl:acl-type = 'ipv4-acl'";      description "additional IP header information";       leaf ipv4-ttl {         type uint8;         description "time to live of a given packet as         defined in RFC791";       }       leaf ipv4-len {Bogdanovic, et al.      Expires December 17, 2017              [Page 38]Internet-Draft               ACL YANG model                    June 2017         type uint16;         description "total packet length as defined in RFC791";       }       leaf ipv4-ihl {         type uint8 {            range 0..15;         }         description "Internet Header Length in 32 bit words                      (see RFC791). Note that while the minimum                      value for this field in a packet is 5,                      we leave open the possibility here that                      the packet has been corrupted.";       }       leaf ipv4-id {         type uint16;         description "Identification as decribed in RFC791";       }       leaf ipv4-flags {         type ipv4-flags-type;         description "IPv4 flags as defined in RFC791";       }       leaf ipv4-offset {         type uint16 {            range 0..8191;         }         description "Matches on the packet fragment offset";       }      }      augment "/ietf-acl:access-lists/ietf-acl:acl/" +              "ietf-acl:access-list-entries/ietf-acl:ace/" +              "ietf-acl:matches" {       description "Newco proprietary simple filter matches";       choice protocol-payload-choice {         description "Newo proprietary payload match condition";         list protocol-payload {           key value-keyword;           ordered-by user;           description "Match protocol payload";           uses match-simple-payload-protocol-value;         }       }       choice metadata {Bogdanovic, et al.      Expires December 17, 2017              [Page 39]Internet-Draft               ACL YANG model                    June 2017         description "Newco proprietary interface match condition";         list interface-name {           key input-interface;           ordered-by user;           description "Match interface name";           uses metadata;         }       }     }     augment "/ietf-acl:access-lists/ietf-acl:acl/" +             "ietf-acl:access-list-entries/ietf-acl:ace/" +             "ietf-acl:actions" {       description "Newco proprietary simple filter actions";       choice action {         description "";         case count {           description "Count the packet in the named counter";           leaf count {             type string;             description "";           }         }         case policer {           description "Name of policer to use to rate-limit traffic";           leaf policer {             type string;             description "";           }         }         case hiearchical-policer {           description "Name of hierarchical policer to use to           rate-limit traffic";           leaf hierarchitacl-policer{             type string;             description "";           }         }       }     }     augment "/ietf-acl:access-lists/ietf-acl:acl" {       description "Newco proprietary default action";       container default-actions {         description           "Actions that occur if no access-list entry is matched.";         leaf deny {           type empty;Bogdanovic, et al.      Expires December 17, 2017              [Page 40]Internet-Draft               ACL YANG model                    June 2017           description "";         }       }     }     grouping metadata {       description       "Fields associated with a packet which are not in       the header.";       leaf input-interface {         type ietf-if:interface-ref {           require-instance false;         }         description           "Packet was received on this interface";       }     }     grouping match-simple-payload-protocol-value {       description "Newco proprietary payload";       leaf value-keyword {         type enumeration {           enum icmp {             description "Internet Control Message Protocol";           }           enum icmp6 {             description "Internet Control Message Protocol Version 6";           }           enum range {             description "Range of values";           }         }         description "(null)";       }     }     augment "/ietf-if:interfaces/ietf-if:interface" {       description "Apply ACL to interfaces";       container acl{         description "ACL related properties.";         leaf acl-name {           type ietf-acl:access-control-list-ref;           description "Access Control List name.";         }         leaf match-counter {           type yang:counter64;           config false;Bogdanovic, et al.      Expires December 17, 2017              [Page 41]Internet-Draft               ACL YANG model                    June 2017           description             "Total match count for Access Control             List on this interface";         }         choice direction {           description "Applying ACL in which traffic direction";           leaf in {             type empty;             description "Inbound traffic";           }           leaf out {             type empty;             description "Outbound traffic";           }         }       }     }     augment "/ietf-acl:access-lists/ietf-acl:acl/" +             "ietf-acl:acl-oper-data" {       description         "This is an example on how to apply acl to a target to collect          operational data";       container targets {         description "To which object is the ACL attached to";         choice interface {           description             "Access Control List was attached to this interface";           leaf-list interface-name{             type ietf-if:interface-ref {             require-instance true;           }           description "Attached to this interface name";         }       }     }   }   Draft authors expect that different vendors will provide their own   yang models as in the example above, which is the augmentation of the   base modelA.3.  Example to augment model with mixed ACL type   As vendors (or IETF) add more features to ACL, the model is easily   augmented.  One of such augmentations can be to add support for mixed   type of ACLs, where acl-type-base can be augmented like in example   below:Bogdanovic, et al.      Expires December 17, 2017              [Page 42]Internet-Draft               ACL YANG model                    June 2017               identity mixed-l3-acl {                 base "access-control-list:acl-type-base";                 description "ACL that contains a mix of entries that                 primarily match on fields in IPv4 headers and entries                 that primarily match on fields in IPv6 headers.          Matching on layer 4 header fields may also exist in the                 list. An acl of type mixed-l3-acl does not contain                 matches on fields in the ethernet header.";               }               identity mixed-l2-l3-acl {                 base "access-control-list:acl-type-base";                 description "ACL that contains a mix of entries that                 primarily match on fields in ethernet headers, entries                 that primarily match on fields in IPv4 headers,          and entries that primarily match on fields in IPv6          headers. Matching on layer 4 header fields may also          exist in the list.";               }A.4.  Linux nftables   As Linux platform is becoming more popular as networking platform,   the Linux data model is changing.  Previously ACLs in Linux were   highly protocol specific and different utilities were used (iptables,   ip6tables, arptables, ebtables), so each one had separate data model.   Recently, this has changed and a single utility, nftables, has been   developed.  With a single application, it has a single data model for   filewall filters and it follows very similarly to the ietf-access-   control list module proposed in this draft.  The nftables support   input and output ACEs and each ACE can be defined with match and   action.   The example in Section 4.3 can be configured using nftable tool as   below.         nft add table ip filter         nft add chain filter input         nft add rule ip filter input ip protocol tcp ip saddr \             10.10.10.1/24 drop   The configuration entries added in nftable would be.Bogdanovic, et al.      Expires December 17, 2017              [Page 43]Internet-Draft               ACL YANG model                    June 2017         table ip filter {           chain input {             ip protocol tcp ip saddr 10.10.10.1/24 drop           }         }   We can see that there are many similarities between Linux nftables   and IETF ACL YANG data models and its extension models.  It should be   fairly easy to do translation between ACL YANG model described in   this draft and Linux nftables.Authors' Addresses   Dean Bogdanovic   Volta Networks   Email: ivandean@gmail.com   Mahesh Jethanandani   Cisco Systems, Inc   Email: mjethanandani@gmail.com   Lisa Huang   General Electric   Email: lyihuang16@gmail.com   Sonal Agarwal   Cisco Systems, Inc.   Email: agarwaso@cisco.com   Dana   Cisco Systems, INc   Email: dblair@cisco.comBogdanovic, et al.      Expires December 17, 2017              [Page 44]