YANG Groupings for UDP Clients and UDP Servers
draft-ietf-netconf-udp-client-server-05

Network Working Group                                      A. Huang Feng
Internet-Draft                                               P. Francois
Intended status: Standards Track                               INSA-Lyon
Expires: 20 April 2025                                         K. Watsen
                                                         Watsen Networks
                                                         17 October 2024

             YANG Groupings for UDP Clients and UDP Servers
                draft-ietf-netconf-udp-client-server-05

Abstract

   This document defines two YANG 1.1 modules to support the
   configuration of UDP clients and UDP servers.

Requirements Language

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

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 20 April 2025.

Copyright Notice

   Copyright (c) 2024 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  The "ietf-udp-client" Module  . . . . . . . . . . . . . . . .   2
     2.1.  Data Model Overview . . . . . . . . . . . . . . . . . . .   3
     2.2.  Example Usage . . . . . . . . . . . . . . . . . . . . . .   4
     2.3.  YANG Module . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  The "ietf-udp-server" Module  . . . . . . . . . . . . . . . .   6
     3.1.  Data Model Overview . . . . . . . . . . . . . . . . . . .   7
     3.2.  Example Usage . . . . . . . . . . . . . . . . . . . . . .   7
     3.3.  YANG Module . . . . . . . . . . . . . . . . . . . . . . .   8
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .  10
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  10
     5.1.  URI . . . . . . . . . . . . . . . . . . . . . . . . . . .  11
     5.2.  YANG module name  . . . . . . . . . . . . . . . . . . . .  11
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  11
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  11
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  11
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  13
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  13

1.  Introduction

   This document defines two YANG 1.1 [RFC7950] modules to support the
   configuration of UDP clients and UDP servers [RFC768].  The data
   models defined by these modules may be used directly (e.g., to define
   a specific UDP client or UDP server) or in conjunction with the
   configuration defined for higher level protocols that depend on UDP.

2.  The "ietf-udp-client" Module

   This section defines a YANG 1.1 module called "ietf-udp-client".
   This YANG module defines the "udp-client" grouping for configuring
   UDP clients with remote server information.

   Section 2.1 provides an overview of the YANG module for configuring
   UDP clients.  An example of usage is illustrated in Section 2.2 and
   Section 2.3 defines the YANG module itself.

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2.1.  Data Model Overview

   This section provides an overview of the features and the grouping
   defined in the "ietf-udp-client" YANG module.

2.1.1.  Features

   The "ietf-udp-client" module defines only one "feature" statements:

   Features:
     +-- local-binding

   This "local-binding" feature indicates that the client supports
   configuring local bindings (i.e., the local address and local port)
   for UDP clients.

   The diagram above uses syntax that is similar to but not defined in
   [RFC8340].

2.1.2.  The "udp-client" Grouping

   The following tree diagram [RFC8340] illustrates the tree structure
   of the "udp-client" grouping:

   module: ietf-udp-client

     grouping udp-client:
       +-- remote-address    inet:host
       +-- remote-port?      inet:port-number
       +-- local-address?    inet:ip-address {local-binding}?
       +-- local-port?       inet:port-number {local-binding}?

   Comments:

   *  The "remote-address", which is mandatory, may be configured as an
      IPv4 address, an IPv6 address, or a hostname.

   *  The "remote-port" is defined with neither a "default" nor a
      "mandatory" statement.  YANG modules using this grouping SHOULD
      refine the grouping with a "default" statement, when the port
      number is well-known (e.g., a port number allocated by IANA), or
      with a "mandatory" statement, if a port number needs to always be
      configured.  This MAY be ignored when the port number is neither
      well-known nor mandatory to configure, such as might be the case
      when this grouping is used by another grouping.

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   *  The "local-address", which is enabled by the "local-binding"
      feature, may be configured as an IPv4 address, an IPv6 address, or
      a wildcard value.

   *  The "local-port", which is enabled by the "local-binding" feature,
      is not mandatory.  Its default value is "0", indicating that the
      operating system can pick an arbitrary port number.

2.2.  Example Usage

   This section presents an example of usage of the "udp-client"
   grouping.

   <!-- The outermost element below doesn't exist in the data model. -->
   <!--  It simulates if the "grouping" were a "container" instead.  -->

   <udp-client xmlns="urn:ietf:params:xml:ns:yang:ietf-udp-client">
     <remote-address>www.example.com</remote-address>
     <remote-port>10000</remote-port>
     <local-address>192.0.2.2</local-address>
     <local-port>12345</local-port>
   </udp-client>

2.3.  YANG Module

   This module imports types defined in [RFC6991].

   <CODE BEGINS> file "ietf-udp-client@2024-10-15"
   module ietf-udp-client {
     yang-version 1.1;
     namespace
       "urn:ietf:params:xml:ns:yang:ietf-udp-client";
     prefix udpc;
     import ietf-inet-types {
       prefix inet;
       reference
         "RFC 6991: Common YANG Data Types";
     }

     organization "IETF NETCONF (Network Configuration) Working Group";
     contact
       "WG Web:   <http:/tools.ietf.org/wg/netconf/>
        WG List:  <mailto:netconf@ietf.org>

        Authors:  Alex Huang Feng
                  <mailto:alex.huang-feng@insa-lyon.fr>
                  Pierre Francois
                  <mailto:pierre.francois@insa-lyon.fr>";

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     description
       "Defines a generic grouping for UDP-based client applications.

       Copyright (c) 2024 IETF Trust and the persons identified as
       authors of the code.  All rights reserved.

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

       This version of this YANG module is part of RFC-to-be; see the RFC
       itself for full legal notices.";

     revision 2024-10-15 {
       description
         "Initial revision";
       reference
         "RFC-to-be: YANG Groupings for UDP Clients and UDP Servers";
     }

     feature local-binding {
       description
         "Indicates that the UDP client supports configuring local
          bindings (i.e., the local address and local port) for
          UDP clients.";
     }

     grouping udp-client {
       description
         "A reusable grouping for configuring a UDP client.

         Note that this grouping uses fairly typical descendant
         node names such that a stack of 'uses' statements will
         have name conflicts.  It is intended that the consuming
         data model will resolve the issue (e.g., by wrapping
         the 'uses' statement in a container called
         'udp-client-parameters').  This model purposely does
         not do this itself so as to provide maximum flexibility
         to consuming models.";

       leaf remote-address {
         type inet:host;
         mandatory true;
         description
           "The IP address or hostname of the remote UDP server.
           If a domain name is configured, then the DNS resolution should

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           happen on each connection attempt. If the DNS resolution
           results in multiple IP addresses, the IP addresses
           are tried according to local preference order until
           a connection has been established or until all IP
           addresses have failed.";
       }

       leaf remote-port {
         type inet:port-number;
         description
           "The port number of the remote UDP server.";
       }

       leaf local-address {
         if-feature "local-binding";
         type inet:ip-address;
         description
           "The local IP address to bind to when sending UDP
           messages to the remote server. INADDR_ANY ('0.0.0.0') or
           INADDR6_ANY ('0:0:0:0:0:0:0:0' a.k.a. '::') may be used
           so that the server can bind to any IPv4 or IPv6 address.";
       }

       leaf local-port {
         if-feature "local-binding";
         type inet:port-number;
         default "0";
         description
           "The local port number to bind to when sending UDP
           messages to the remote server. The port number '0',
           which is the default value, indicates that any available
           local port number may be used.";
       }
     }
   }
   <CODE ENDS>

3.  The "ietf-udp-server" Module

   This section defines a YANG 1.1 module called "ietf-udp-server".
   This YANG module defines the "udp-server" grouping for configuring
   UDP servers.

   Section 3.1 provides an overview of the YANG module for configuring
   UDP servers.  An example of usage is illustrated in Section 3.2 while
   Section 3.3 defines the YANG module itself.

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3.1.  Data Model Overview

   This section provides an overview of the grouping defined in the
   "ietf-udp-server" module.

3.1.1.  The "udp-server" Grouping

   The following tree diagram [RFC8340] illustrates the structure of
   "udp-server" grouping:

   module: ietf-udp-server

     grouping udp-server:
       +-- local-bind* [local-address]
          +-- local-address    inet:ip-address
          +-- local-port?      inet:port-number

   Comments:

   *  The "local-address", which is mandatory, may be configured as an
      IPv4 address, an IPv6 address, or a wildcard value.

   *  The "local-port" is defined with neither a "default" nor a
      "mandatory" statement.  YANG modules using this grouping SHOULD
      refine the grouping with a "default" statement, when the port
      number is well-known (e.g., a port number allocated by IANA), or
      with a "mandatory" statement, if a port number needs to always be
      configured.  This MAY be ignored when the port number is neither
      well-known nor mandatory to configure, such as might be the case
      when this grouping is used by another grouping.

3.2.  Example Usage

   This section presents two examples of usage of the "udp-server"
   grouping.

   This following shows an example of a server configured for listening
   to an IPv4 address:

   <!-- The outermost element below doesn't exist in the data model. -->
   <!--  It simulates if the "grouping" were a "container" instead.  -->

   <udp-server xmlns="urn:ietf:params:xml:ns:yang:ietf-udp-server">
     <local-bind>
       <local-address>192.0.2.2</local-address>
       <local-port>49152</local-port>
     </local-bind>
   </udp-server>

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   This example shows an example of a server configured to listen to an
   IPv4 and IPv6 together:

   <!-- The outermost element below doesn't exist in the data model. -->
   <!--  It simulates if the "grouping" were a "container" instead.  -->

   <udp-server xmlns="urn:ietf:params:xml:ns:yang:ietf-udp-server">
     <local-bind>
       <local-address>192.0.2.2</local-address>
       <local-port>49152</local-port>
     </local-bind>
     <local-bind>
       <local-address>2001:db8::0</local-address>
       <local-port>49153</local-port>
     </local-bind>
   </udp-server>

3.3.  YANG Module

   The "ietf-udp-server" imports types defined in [RFC6991].

   <CODE BEGINS> file "ietf-udp-server@2024-10-15.yang"
   module ietf-udp-server {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:ietf-udp-server";
     prefix udps;

     import ietf-inet-types {
       prefix inet;
       reference
         "RFC 6991: Common YANG Data Types";
     }

     organization
       "IETF NETCONF (Network Configuration) Working Group";
     contact
       "WG Web:   <http:/tools.ietf.org/wg/netconf/>
        WG List:  <mailto:netconf@ietf.org>

        Authors:  Alex Huang Feng
                  <mailto:alex.huang-feng@insa-lyon.fr>
                  Pierre Francois
                  <mailto:pierre.francois@insa-lyon.fr>";
     description
       "Defines a generic grouping for UDP-based server applications.

        Copyright (c) 2024 IETF Trust and the persons identified as
        authors of the code.  All rights reserved.

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

        This version of this YANG module is part of RFC-to-be; see the RFC
        itself for full legal notices.";

     revision 2024-10-15 {
       description
         "Initial revision";
       reference
         "RFC-to-be: YANG Groupings for UDP Clients and UDP Servers";
     }

     grouping udp-server {
       description
         "Provides a reusable grouping for configuring a UDP server.

          Note that this grouping uses fairly typical descendant
          node names such that a stack of 'uses' statements will
          have name conflicts.  It is intended that the consuming
          data model will resolve the issue (e.g., by wrapping
          the 'uses' statement in a container called
          'udp-server-parameters').  This model purposely does
          not do this itself so as to provide maximum flexibility
          to consuming models.";
       list local-bind {
         key "local-address";
         min-elements 1;
         description
           "A list of bind (listen) points for this server
            instance.  A server instance may have multiple
            bind points to support, e.g., the same port in
            different address families or different ports
            in the same address family.";
         leaf local-address {
           type inet:ip-address;
           mandatory true;
           description
             "The local IP address to listen on for incoming
              UDP messages.  To configure listening
              on all IPv4 addresses the value must be '0.0.0.0'
              (INADDR_ANY).  To configure listening on all IPv6
              addresses the value must be '::' (INADDR6_ANY).";
         }
         leaf local-port {

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           type inet:port-number;
           description
             "The local port number to listen on for incoming UDP
              messages.";
         }
       }
     }
   }
   <CODE ENDS>

4.  Security Considerations

   This section uses the template described in Section 3.7 of
   [I-D.ietf-netmod-rfc8407bis].

   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].  These network management
   protocols are required to use a secure transport layer and mutual
   authentication, e.g., SSH [RFC6242] without the "none" authentication
   option, Transport Layer Security (TLS) [RFC8446] with mutual X.509
   authentication, and HTTPS with HTTP authentication (Section 11 of
   [RFC9110]).

   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.

   The YANG module defines a set of identities, types, and groupings.
   These nodes are intended to be reused by other YANG modules.  The
   module by itself does not expose any data nodes that are writable,
   data nodes that contain read-only state, or RPCs.  As such, there are
   no additional security issues related to the YANG module that need to
   be considered.

   Modules that use the groupings that are defined in this document
   should identify the corresponding security considerations.  For
   example, reusing some of these groupings will expose privacy-related
   information (e.g., 'node-example').

5.  IANA Considerations

   This document describes the URIs from IETF XML Registry and the
   registration of a two new YANG module names

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5.1.  URI

   IANA is requested to assign two new URIs from the IETF XML Registry
   [RFC3688].  The following two URIs are suggested:

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

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

5.2.  YANG module name

   This document also requests IANA to register the following YANG
   modules in the YANG Module Names registry [RFC6020] within the "YANG
   Parameters" registry group:

   name: ietf-udp-client
   namespace: urn:ietf:params:xml:ns:yang:ietf-udp-client
   prefix: udpc
   maintained by IANA? N
   reference: RFC-to-be

   name: ietf-udp-server
   namespace: urn:ietf:params:xml:ns:yang:ietf-udp-server
   prefix: udps
   maintained by IANA? N
   reference: RFC-to-be

6.  Acknowledgements

   The authors would like to thank Mohamed Boucadair, Benoit Claise,
   Qiufang Ma and Qin Wu for their review and valuable comments.

7.  References

7.1.  Normative References

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

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

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   [RFC6020]  Bjorklund, M., Ed., "YANG - A Data Modeling Language for
              the Network Configuration Protocol (NETCONF)", RFC 6020,
              DOI 10.17487/RFC6020, October 2010,
              <https://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,
              <https://www.rfc-editor.org/info/rfc6241>.

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

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

   [RFC768]   Postel, J., "User Datagram Protocol", STD 6, RFC 768,
              DOI 10.17487/RFC0768, August 1980,
              <https://www.rfc-editor.org/info/rfc768>.

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

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

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

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

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

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

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

7.2.  Informative References

   [I-D.ietf-netmod-rfc8407bis]
              Bierman, A., Boucadair, M., and Q. Wu, "Guidelines for
              Authors and Reviewers of Documents Containing YANG Data
              Models", Work in Progress, Internet-Draft, draft-ietf-
              netmod-rfc8407bis-18, 11 October 2024,
              <https://datatracker.ietf.org/doc/html/draft-ietf-netmod-
              rfc8407bis-18>.

Authors' Addresses

   Alex Huang Feng
   INSA-Lyon
   Lyon
   France
   Email: alex.huang-feng@insa-lyon.fr

   Pierre Francois
   INSA-Lyon
   Lyon
   France
   Email: pierre.francois@insa-lyon.fr

   Kent Watsen
   Watsen Networks
   Email: kent+ietf@watsen.net

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