如何向Delphi中的HLDS服务器发送一个UDP数据包？

Question

我正在尝试将 A2A_PING UDP 数据包发送到 HLDS 服务器，如 here using Delphi XE4. However, I'm not getting any response. When I tested using Packet Sender 所述，我在数据包发送器中得到了预期的响应。

我想做的是创建一个服务器监视器以在它的 UDP 端口上发送 ping。因此，我的应用程序将始终运行在服务器上本地使用其本地 IP。服务器的UDP端口是27015.

我要发送的 UDP 数据包是：

Hex: FF FF FF FF 69

String equivalent: ÿÿÿÿi

这是我到目前为止所做的努力：

unit uFrmMain;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, ShellAPI, IdUDPServer, IdBaseComponent, IdComponent,
  IdUDPBase, IdUDPClient, IdSocketHandle, IdGlobal;

type
  TfrmMain = class(TForm)
    ListBox1: TListBox;
    btnSendMessage: TButton;
    btnInitialize: TButton;
    procedure btnSendMessageClick(Sender: TObject);
    procedure IdUDPServer1UDPRead(AThread: TIdUDPListenerThread; const AData: TIdBytes; ABinding: TIdSocketHandle);
    procedure btnInitializeClick(Sender: TObject);
  private
    function String2Hex(const Buffer: Ansistring): string;
    procedure Initialize;
  public
    { Public declarations }
  end;

const
  Host = '172.30.0.96';
  TargetPort = 27015;
  LocalListenPort = 47001;
  MessageToSend = 'ÿÿÿÿi';  // need to send: FF FF FF FF 69

var
  frmMain: TfrmMain;
  udpServer: TIdUDPServer;
  udpClient: TIdUDPClient;

implementation

{$R *.dfm}

procedure TfrmMain.Initialize;
var
  binding: TIdSocketHandle;
begin
  // Setup UDP Server
  udpServer := TIdUDPServer.Create(frmMain);
  udpServer.Active := false;
  binding := udpServer.Bindings.Add;
  Binding.IP := Host;                 // local host ip
  binding.Port := LocalListenPort;    // Listen for incoming messages on 47001
  udpServer.OnUDPRead := IdUDPServer1UDPRead;
  udpServer.Active := true;

  // Setup UDP client
  udpClient := TIdUDPClient.Create(frmMain);
  udpClient.Host := Host;       // Local host ip
  udpClient.Port := TargetPort; // Send messages to 27015
  udpClient.Active := true;
end;

procedure TfrmMain.btnInitializeClick(Sender: TObject);
begin
  Initialize;
end;

procedure TfrmMain.btnSendMessageClick(Sender: TObject);
begin
    udpClient.SendBuffer(Host, TargetPort, ToBytes(MessageToSend));
end;

procedure TfrmMain.IdUDPServer1UDPRead(AThread: TIdUDPListenerThread; const AData: TIdBytes; ABinding: TIdSocketHandle);
begin
    ListBox1.Items.Add(BytesToString(AData));
end;

function TfrmMain.String2Hex(const Buffer: Ansistring): string;
begin
  SetLength(result, 2*Length(Buffer));
  BinToHex(@Buffer[1], PWideChar(@result[1]), Length(Buffer));
end;

end.

UPDATE 根据雷米的建议，我也试过了：

unit uFrmMain;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, ShellAPI, IdUDPServer, IdBaseComponent, IdComponent,
  IdUDPBase, IdUDPClient, IdSocketHandle, IdGlobal;

type
  TfrmMain = class(TForm)
    ListBox1: TListBox;
    btnSendMessage: TButton;
    btnInitialize: TButton;
    procedure btnSendMessageClick(Sender: TObject);
    procedure IdUDPServer1UDPRead(AThread: TIdUDPListenerThread; const AData: TIdBytes; ABinding: TIdSocketHandle);
    procedure btnInitializeClick(Sender: TObject);
  private
    function String2Hex(const Buffer: Ansistring): string;
    procedure Initialize;
  public
    { Public declarations }
  end;

const
//  Host = '172.30.0.96';
  Host = '192.168.190.1';
  TargetPort = 27015;
  LocalListenPort = 47001;

var
  frmMain: TfrmMain;
  udpServer: TIdUDPServer;
//  udpClient: TIdUDPClient;
  binding: TIdSocketHandle;

implementation

{$R *.dfm}

procedure TfrmMain.Initialize;
var
  bytes_received: integer;
begin
  // Setup UDP Server
  udpServer := TIdUDPServer.Create(frmMain);
  udpServer.Active := false;
  udpServer.DefaultPort := 0;
  binding := udpServer.Bindings.Add;
  Binding.IP := Host;                 // local host ip
  binding.Port := LocalListenPort;    // Listen for incoming messages on 47001
  udpServer.OnUDPRead := IdUDPServer1UDPRead;
  udpServer.Active := true;

  // Setup UDP client
//  udpClient := TIdUDPClient.Create(frmMain);
//  udpClient.Host := Host;       // Local host ip
//  udpClient.Port := TargetPort; // Send messages to 27015
//  udpClient.BoundIP := Host;
//  udpClient.BoundPort := LocalListenPort;
//  udpClient.ReceiveTimeout := 2000;
//  udpClient.Active := true;
end;

procedure TfrmMain.btnInitializeClick(Sender: TObject);
begin
  Initialize;
end;

procedure TfrmMain.btnSendMessageClick(Sender: TObject);
var
  MessageToSend: TIdBytes;
begin
  SetLength(MessageToSend, 5);
  MessageToSend[0] := $FF;
  MessageToSend[1] := $FF;
  MessageToSend[2] := $FF;
  MessageToSend[3] := $FF;
  MessageToSend[4] := ;
//  udpClient.SendBuffer(Host, TargetPort, RawToBytes(MessageToSend, SizeOf(MessageToSend)));
  binding.SendTo(Host, TargetPort, RawToBytes(MessageToSend, SizeOf(MessageToSend)));
end;

procedure TfrmMain.IdUDPServer1UDPRead(AThread: TIdUDPListenerThread; const AData: TIdBytes; ABinding: TIdSocketHandle);
begin
    ListBox1.Items.Add(ToHex(AData));
end;

end.

我一定遗漏了一些非常明显的东西，因为 Packet Sender 工作得很好。非常感谢任何帮助。

Answer 1

您不应在消息中使用字符串（如果您使用的是 Delphi 2009+，尤其是 Unicode 字符串）。您使用的协议本质上是二进制的，而不是文本的。您需要使用原始字节进行操作，例如：

const
  MessageToSend: array[0..4] of Byte = ($FF, $FF, $FF, $FF, );

procedure TfrmMain.btnSendMessageClick(Sender: TObject);
begin
  udpClient.SendBuffer(Host, TargetPort, RawToBytes(MessageToSend, SizeOf(MessageToSend));
end;

{
Alternatively:

procedure TfrmMain.btnSendMessageClick(Sender: TObject);
var
  MessageToSend: TIdBytes;
begin
  SetLength(MessageToSend, 5);
  MessageToSend[0] := $FF;
  MessageToSend[1] := $FF;
  MessageToSend[2] := $FF;
  MessageToSend[3] := $FF;
  MessageToSend[4] := ;
  udpClient.SendBuffer(Host, TargetPort, MessageToSend);
end;
}

procedure TfrmMain.IdUDPServer1UDPRead(AThread: TIdUDPListenerThread; const AData: TIdBytes; ABinding: TIdSocketHandle);
begin
  ListBox1.Items.Add(ToHex(AData));
end;

如何向Delphi中的HLDS服务器发送一个UDP数据包？

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