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Versions: 00 01 02 draft-ietf-netconf-tcp-client-server

NETCONF Working Group                                          K. Watsen
Internet-Draft                                           Watsen Networks
Intended status: Standards Track                           March 9, 2019
Expires: September 10, 2019


             YANG Groupings for TCP Clients and TCP Servers
               draft-kwatsen-netconf-tcp-client-server-00

Abstract

   This document defines two YANG modules: the first defines a grouping
   for configuring a generic TCP client, and the second defines a
   grouping for configuring a generic TCP server.  It is intended that
   these groupings will be used by applications using the TCP protocol.

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.  No other RFC
   Editor instructions are specified elsewhere in this document.

   Artwork in this document contains placeholder values for the date of
   publication of this draft.  Please apply the following replacement:

   o  "2019-03-09" --> the publication date of this draft

   The following Appendix section is to be removed prior to publication:

   o  Appendix A.  Change Log

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 September 10, 2019.



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Copyright Notice

   Copyright (c) 2019 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  The TCP Client Model  . . . . . . . . . . . . . . . . . . . .   3
     3.1.  Tree Diagram  . . . . . . . . . . . . . . . . . . . . . .   3
     3.2.  Example Usage . . . . . . . . . . . . . . . . . . . . . .   3
     3.3.  YANG Module . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  The TCP Server Model  . . . . . . . . . . . . . . . . . . . .   7
     4.1.  Tree Diagram  . . . . . . . . . . . . . . . . . . . . . .   7
     4.2.  Example Usage . . . . . . . . . . . . . . . . . . . . . .   8
     4.3.  YANG Module . . . . . . . . . . . . . . . . . . . . . . .   8
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  11
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  12
     6.1.  The IETF XML Registry . . . . . . . . . . . . . . . . . .  12
     6.2.  The YANG Module Names Registry  . . . . . . . . . . . . .  13
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  13
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  13
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  14
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  14

1.  Introduction

   This document defines two YANG 1.1 [RFC7950] modules: the first
   defines a grouping for configuring a generic TCP client, and the
   second defines a grouping for configuring a generic TCP server.  It
   is intended that these groupings will be used by applications using
   the TCP protocol.  For instance, these groupings could help define
   the configuration module for an SSH, TLS, or HTTP based application.







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2.  Terminology

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

3.  The TCP Client Model

3.1.  Tree Diagram

   This section provides a tree diagram [RFC8340] for the "ietf-tcp-
   client" module.

   module: ietf-tcp-client

     grouping tcp-client-grouping
       +-- remote-address    inet:host
       +-- remote-port?      inet:port-number
       +-- local-address?    inet:ip-address
       +-- local-port?       inet:port-number
       +-- tcp-keepalives {tcp-client-keepalives}?
          +-- idle-time?        uint16
          +-- max-probes?       uint16
          +-- probe-interval?   uint16
     grouping ip-params-grouping
       +-- remote-address    inet:host
       +-- remote-port?      inet:port-number
       +-- local-address?    inet:ip-address
       +-- local-port?       inet:port-number
     grouping keepalives-grouping
       +-- tcp-keepalives {tcp-client-keepalives}?
          +-- idle-time?        uint16
          +-- max-probes?       uint16
          +-- probe-interval?   uint16

3.2.  Example Usage

   This section presents an example showing the tcp-client-grouping
   populated with some data.










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   <tcp-client xmlns="urn:ietf:params:xml:ns:yang:ietf-tcp-client">
     <remote-address>www.example.com</remote-address>
     <remote-port>443</remote-port>
     <local-address>0.0.0.0</local-address>
     <local-port>0</local-port>
     <tcp-keepalives>
       <idle-time>15</idle-time>
       <max-probes>3</max-probes>
       <probe-interval>30</probe-interval>
     </tcp-keepalives>
   </tcp-client>

3.3.  YANG Module

   This YANG module has normative references to [RFC6991].

  <CODE BEGINS> file "ietf-tcp-client@2019-03-09.yang"
  module ietf-tcp-client {
    yang-version 1.1;
    namespace "urn:ietf:params:xml:ns:yang:ietf-tcp-client";
    prefix tcpc;

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

    organization
      "IETF NETCONF (Network Configuration) Working Group";

    contact
      "WG Web:   <http://datatracker.ietf.org/wg/netconf/>
       WG List:  <mailto:netconf@ietf.org>
       Author:   Kent Watsen <mailto:kent+ietf@watsen.net>";

    description
      "This module defines reusable groupings for TCP clients that
       can be used as a basis for specific TCP client instances.

       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.

       Copyright (c) 2019 IETF Trust and the persons identified as



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       authors of the code. All rights reserved.

       Redistribution and use in source and binary forms, with or
       without modification, is permitted pursuant to, and subject
       to the license terms contained in, the Simplified BSD
       License set forth in Section 4.c of the IETF Trust's
       Legal Provisions Relating to IETF Documents
       (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 2019-03-09 {
      description
        "Initial version";
      reference
        "RFC XXXX: YANG Groupings for TCP Clients and TCP Servers";
    }

    // Features

    feature tcp-client-keepalives {
      description
        "Per socket TCP keepalive parameters are configurable for
         TCP clients on the server implementing this feature.";
    }

    // Groupings

    grouping tcp-client-grouping {
      description
        "A reusable grouping for configuring a TCP client.";
      uses ip-params-grouping;
      uses keepalives-grouping;
    }

    grouping ip-params-grouping {
      description
        "A reusable grouping for configuring TCP client IP level
         parameters.";
      leaf remote-address {
        type inet:host;
        mandatory true;
        description
          "The IP address or hostname of the remote peer to connect to.
           If a domain name is configured, then the DNS resolution
           should happen on each connection attempt.  If the the DNS
           resolution results in multiple IP addresses, the IP addresses



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           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;
        default "0";
        description
          "The IP port number for the remote peer  to connect to.  An
           invalid default value (0) is used (instead of 'mandatory
           true') so that a application level data model may 'refine'
           it with an application specific default port number value.";
      }
      leaf local-address {
        type inet:ip-address;
        description
          "The local IP address/interface (VRF?) to bind to for when
           connecting to the remote peer.  INADDR_ANY ('0.0.0.0') or
           INADDR6_ANY ('0:0:0:0:0:0:0:0' a.k.a. '::') MAY be used to
           explicitly indicate the implicit default, that the server
           can bind to any IPv4 or IPv6 addresses, respectively.";
      }
      leaf local-port {
        type inet:port-number;
        default "0";
        description
          "The local IP port number to bind to for when connecting to
           the remote peer.  The port number '0', which is the default
           value, indicates that any available local port number may
           be used.";
      }
    }

    grouping keepalives-grouping {
      description
        "A reusable grouping for configuring TCP client keepalive
         parameters.";
      container tcp-keepalives {
        if-feature "tcp-client-keepalives";
        description
          "Configures the keep-alive policy, to proactively test the
           aliveness of the TCP server.  Not all clients will use
           all the values, based on capabilities of the underlying
           operating system.  An unresponsive TCP server is dropped
           after approximately (idle-time * 60) + (max-probes *
           probe-interval) seconds.";
        leaf idle-time {
          type uint16 {



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            range "1..max";
          }
          units "minutes";
          description
            "Sets the amount of time in minutes after which if no data
             has been received from the TCP server, a TCP-level probe
             message will be sent to test the aliveness of the TCP
             server.  When 'idle-time' is not configured (the default)
             TCP keep-alives are disabled.";
        }
        leaf max-probes {
          type uint16 {
            range "1..max";
          }
          description
            "Sets the maximum number of sequential keep-alive probes
             that can fail to obtain a response from the TCP server
             before assuming the TCP server is no longer alive.  If
             no value is specified, then the operating system provided
             default value is used.";
        }
        leaf probe-interval {
          type uint16 {
            range "1..max";
          }
          units "seconds";
          description
            "Sets the time interval between failed probes.  If no value
             is specified, then the operating system provided default
             value is used.";
        }
      }
    }
  }
  <CODE ENDS>

4.  The TCP Server Model

4.1.  Tree Diagram

   This section provides a tree diagram [RFC8340] for the "ietf-tcp-
   server" module.









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   module: ietf-tcp-server

     grouping tcp-server-grouping
       +-- local-address     inet:ip-address
       +-- local-port?       inet:port-number
       +-- tcp-keepalives {tcp-server-keepalives}?
          +-- idle-time?        uint16
          +-- max-probes?       uint16
          +-- probe-interval?   uint16
     grouping ip-params-grouping
       +-- local-address    inet:ip-address
       +-- local-port?      inet:port-number
     grouping keepalives-grouping
       +-- tcp-keepalives {tcp-server-keepalives}?
          +-- idle-time?        uint16
          +-- max-probes?       uint16
          +-- probe-interval?   uint16

4.2.  Example Usage

   This section presents an example showing the tcp-server-grouping
   populated with some data.

   <tcp-server xmlns="urn:ietf:params:xml:ns:yang:ietf-tcp-server">
     <local-address>10.20.30.40</local-address>
     <local-port>7777</local-port>
     <tcp-keepalives>
       <idle-time>15</idle-time>
       <max-probes>3</max-probes>
       <probe-interval>30</probe-interval>
     </tcp-keepalives>
   </tcp-server>

4.3.  YANG Module

   This YANG module has normative references to [RFC6991].

   <CODE BEGINS> file "ietf-tcp-server@2019-03-09.yang"
   module ietf-tcp-server {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:ietf-tcp-server";
     prefix tcps;

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



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     organization
       "IETF NETCONF (Network Configuration) Working Group";

     contact
       "WG Web:   <http://datatracker.ietf.org/wg/netconf/>
        WG List:  <mailto:netconf@ietf.org>
        Author:   Kent Watsen <mailto:kent+ietf@watsen.net>";

     description
       "This module defines reusable groupings for TCP servers that
        can be used as a basis for specific TCP server instances.

        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.

        Copyright (c) 2019 IETF Trust and the persons identified as
        authors of the code. All rights reserved.

        Redistribution and use in source and binary forms, with or
        without modification, is permitted pursuant to, and subject
        to the license terms contained in, the Simplified BSD
        License set forth in Section 4.c of the IETF Trust's
        Legal Provisions Relating to IETF Documents
        (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 2019-03-09 {
       description
         "Initial version";
       reference
         "RFC XXXX: YANG Groupings for TCP Clients and TCP Servers";
     }

     // Features

     feature tcp-server-keepalives {
       description
         "Per socket TCP keepalive parameters are configurable for
          TCP servers on the server implementing this feature.";
     }

     // Groupings



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     grouping tcp-server-grouping {
       description
         "A reusable grouping for configuring a TCP server.";
       uses ip-params-grouping;
       uses keepalives-grouping;
     }

     grouping ip-params-grouping {
       description
         "A reusable grouping for configuring TCP server IP level
          parameters.";
       leaf local-address {
         type inet:ip-address;
         mandatory true;
         description
           "The local IP address to listen on for incoming TCL
            client connections.  INADDR_ANY (0.0.0.0) or INADDR6_ANY
            (0:0:0:0:0:0:0:0 a.k.a. ::) MUST be used when the server
            is to listen on all IPv4 or IPv6 addresses, respectively.";
       }
       leaf local-port {
         type inet:port-number;
         default "0";
         description
           "The local port number to listen on for incoming TCP client
            connections.  An invalid default value (0) is used (instead
            of 'mandatory true') so that a application level data model
            may 'refine' it with an application specific default port
            number value.";
       }
     }

     grouping keepalives-grouping {
       description
         "A reusable grouping for configuring TCP server keepalive
          parameters.";
       container tcp-keepalives {
         if-feature "tcp-server-keepalives";
         description
           "Configures the keep-alive policy, to proactively test the
            aliveness of the TCP client.  Not all servers will use
            all the values, based on capabilities of the underlying
            operating system.  An unresponsive TCP client is dropped
            after approximately (idle-time * 60) + (max-probes *
            probe-interval) seconds.";
         leaf idle-time {
           type uint16 {
             range "1..max";



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           }
           units "minutes";
           description
             "Sets the amount of time in minutes after which if no data
              has been received from the TCP client, a TCP-level probe
              message will be sent to test the aliveness of the TCP
              client.  When 'idle-time' is not configured (the default)
              TCP keep-alives are disabled.";
         }
         leaf max-probes {
           type uint16 {
             range "1..max";
           }
           description
             "Sets the maximum number of sequential keep-alive probes
              that can fail to obtain a response from the TCP client
              before assuming the TCP client is no longer alive.  If
              no value is specified, then the operating system provided
              default value is used.";
         }
         leaf probe-interval {
           type uint16 {
             range "1..max";
           }
           units "seconds";
           description
             "Sets the time interval between failed probes.  If no value
              is specified, then the operating system provided default
              value is used.";
         }
       }
     }
   }
   <CODE ENDS>

5.  Security Considerations

   The YANG modules defined in this document are designed to be accessed
   via YANG based management protocols, such as NETCONF [RFC6241] and
   RESTCONF [RFC8040].  Both of these protocols have mandatory-to-
   implement secure transport layers (e.g., SSH, TCP) with mutual
   authentication.

   The NETCONF access control model (NACM) [RFC8341] provides the means
   to restrict access for particular users to a pre-configured subset of
   all available protocol operations and content.





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   Since the modules defined in this document only define groupings,
   these considerations are primarily for the designers of other modules
   that use these groupings.

   There are a number of data nodes defined in the YANG modules that 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:

      NONE

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

      NONE

   Some of the RPC operations in this YANG module may be considered
   sensitive or vulnerable in some network environments.  It is thus
   important to control access to these operations.  These are the
   operations and their sensitivity/vulnerability:

      NONE

6.  IANA Considerations

6.1.  The IETF XML Registry

   This document registers two URIs in the "ns" subregistry of the IETF
   XML Registry [RFC3688].  Following the format in [RFC3688], the
   following registrations are requested:

      URI: urn:ietf:params:xml:ns:yang:ietf-tcp-client
      Registrant Contact: The NETCONF WG of the IETF.
      XML: N/A, the requested URI is an XML namespace.

      URI: urn:ietf:params:xml:ns:yang:ietf-tcp-server
      Registrant Contact: The NETCONF WG of the IETF.
      XML: N/A, the requested URI is an XML namespace.







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6.2.  The YANG Module Names Registry

   This document registers two YANG modules in the YANG Module Names
   registry [RFC6020].  Following the format in [RFC6020], the following
   registrations are requested:

      name:         ietf-tcp-client
      namespace:    urn:ietf:params:xml:ns:yang:ietf-tcp-client
      prefix:       tcpc
      reference:    RFC XXXX

      name:         ietf-tcp-server
      namespace:    urn:ietf:params:xml:ns:yang:ietf-tcp-server
      prefix:       tcps
      reference:    RFC XXXX

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>.

   [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>.

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

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

   [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>.

   [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>.





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7.2.  Informative References

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

   [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>.

   [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>.

   [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>.

Author's Address

   Kent Watsen
   Watsen Networks

   EMail: kent+ietf@watsen.net


























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