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";
  }

  import ietf-tcp-common {
    prefix tcpcmn;
    reference
      "RFC DDDD: YANG Groupings for TCP Clients and TCP Servers";
  }

  organization
    "IETF NETCONF (Network Configuration) Working Group and the
     IETF TCP Maintenance and Minor Extensions (TCPM) Working Group";

  contact
    "WG Web:   https://datatracker.ietf.org/wg/netconf
               https://datatracker.ietf.org/wg/tcpm
     WG List:  NETCONF WG list <mailto:netconf@ietf.org>
               TCPM WG list <mailto:tcpm@ietf.org>
     Authors:  Kent Watsen <mailto:kent+ietf@watsen.net>
               Michael Scharf
               <mailto:michael.scharf@hs-esslingen.de>";

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

     Copyright (c) 2023 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 DDDD
     (https://www.rfc-editor.org/info/rfcDDDD); see the RFC
     itself for full legal notices.

     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 (RFC 2119)
     (RFC 8174) when, and only when, they appear in all
     capitals, as shown here.";

  revision 2023-12-28 {
    description
      "Initial version";
    reference
      "RFC DDDD: 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.";
    reference
      "RFC 9293: Transmission Control Protocol (TCP)";
  }

  // Groupings

  grouping tcp-server-grouping {
    description
      "A reusable grouping for configuring a TCP 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
       'tcp-server-parameters').  This model purposely does
       not do this itself so as to provide maximum flexibility
       to consuming models.";
    leaf local-address {
      type inet:ip-address;
      mandatory true;
      description
        "The local IP address to listen on for incoming
         TCP 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 an
         application level data model may 'refine' it with
         an application specific default port number value.";
    }
    uses tcpcmn:tcp-common-grouping {
      refine "keepalives" {
        if-feature "tcp-server-keepalives";
        description
          "Add an if-feature statement so that implementations
           can choose to support TCP server keepalives.";
      }
    }
  }
}