syntax = "proto3";

package envoy.config.core.v3;

import "udpa/annotations/status.proto";
import "udpa/annotations/versioning.proto";
import "validate/validate.proto";

option java_package = "io.envoyproxy.envoy.config.core.v3";
option java_outer_classname = "SocketOptionProto";
option java_multiple_files = true;
option go_package = "github.com/envoyproxy/go-control-plane/envoy/config/core/v3;corev3";
option (udpa.annotations.file_status).package_version_status = ACTIVE;

// [#protodoc-title: Socket Option ]

// Generic socket option message. This would be used to set socket options that
// might not exist in upstream kernels or precompiled Envoy binaries.
//
// For example:
//
// .. code-block:: json
//
//  {
//    "description": "support tcp keep alive",
//    "state": 0,
//    "level": 1,
//    "name": 9,
//    "int_value": 1,
//  }
//
// 1 means SOL_SOCKET and 9 means SO_KEEPALIVE on Linux.
// With the above configuration, `TCP Keep-Alives <https://www.freesoft.org/CIE/RFC/1122/114.htm>`_
// can be enabled in socket with Linux, which can be used in
// :ref:`listener's<envoy_v3_api_field_config.listener.v3.Listener.socket_options>` or
// :ref:`admin's <envoy_v3_api_field_config.bootstrap.v3.Admin.socket_options>` socket_options etc.
//
// It should be noted that the name or level may have different values on different platforms.
// [#next-free-field: 7]
message SocketOption {
  option (udpa.annotations.versioning).previous_message_type = "envoy.api.v2.core.SocketOption";

  enum SocketState {
    // Socket options are applied after socket creation but before binding the socket to a port
    STATE_PREBIND = 0;

    // Socket options are applied after binding the socket to a port but before calling listen()
    STATE_BOUND = 1;

    // Socket options are applied after calling listen()
    STATE_LISTENING = 2;
  }

  // An optional name to give this socket option for debugging, etc.
  // Uniqueness is not required and no special meaning is assumed.
  string description = 1;

  // Corresponding to the level value passed to setsockopt, such as IPPROTO_TCP
  int64 level = 2;

  // The numeric name as passed to setsockopt
  int64 name = 3;

  oneof value {
    option (validate.required) = true;

    // Because many sockopts take an int value.
    int64 int_value = 4;

    // Otherwise it's a byte buffer.
    bytes buf_value = 5;
  }

  // The state in which the option will be applied. When used in BindConfig
  // STATE_PREBIND is currently the only valid value.
  SocketState state = 6 [(validate.rules).enum = {defined_only: true}];
}
