Indy/Lib/Core/IdCustomTransparentProxy.pas

{
  $Project$
  $Workfile$
  $Revision$
  $DateUTC$
  $Id$

  This file is part of the Indy (Internet Direct) project, and is offered
  under the dual-licensing agreement described on the Indy website.
  (http://www.indyproject.org/)

  Copyright:
   (c) 1993-2005, Chad Z. Hower and the Indy Pit Crew. All rights reserved.
}
{
  $Log$
}
{
  Rev 1.10    11/12/2004 11:30:16 AM  JPMugaas
  Expansions for IPv6.

  Rev 1.9    11/11/2004 10:25:22 PM  JPMugaas
  Added OpenProxy and CloseProxy so you can do RecvFrom and SendTo functions
  from the UDP client with SOCKS.  You must call OpenProxy  before using
  RecvFrom or SendTo.  When you are finished, you must use CloseProxy to close
  any connection to the Proxy.  Connect and disconnect also call OpenProxy and
  CloseProxy.

  Rev 1.8    11/11/2004 3:42:52 AM  JPMugaas
  Moved strings into RS.  Socks will now raise an exception if you attempt to
  use SOCKS4 and SOCKS4A with UDP.  Those protocol versions do not support UDP
  at all.

  Rev 1.7    11/9/2004 8:18:00 PM  JPMugaas
  Attempt to add SOCKS support in UDP.

  Rev 1.6    6/6/2004 11:51:56 AM  JPMugaas
  Fixed TODO with an exception

  Rev 1.5    2004.02.03 4:17:04 PM  czhower
  For unit name changes.

    Rev 1.4    10/15/2003 10:59:06 PM  DSiders
  Corrected spelling error in resource string name.
  Added resource string for circular links exception in transparent proxy.

    Rev 1.3    10/15/2003 10:10:18 PM  DSiders
  Added localization comments.

    Rev 1.2    5/16/2003 9:22:38 AM  BGooijen
  Added Listen(...)

    Rev 1.1    5/14/2003 6:41:00 PM  BGooijen
  Added Bind(...)

  Rev 1.0    12/2/2002 05:01:26 PM  JPMugaas
  Rechecked in due to file corruption.
}

unit IdCustomTransparentProxy;

interface

{$I IdCompilerDefines.inc}
//we need to put this in Delphi mode to work

uses
  Classes,
  IdComponent,
  IdException,
  IdGlobal,
  IdIOHandler,
  IdSocketHandle,
  IdBaseComponent;

type
  EIdTransparentProxyCircularLink = class(EIdException);
  EIdTransparentProxyUDPNotSupported = class(EIdException);

  TIdCustomTransparentProxyClass = class of TIdCustomTransparentProxy;

  TIdCustomTransparentProxy = class(TIdComponent)
  protected
    FHost: String;
    FPassword: String;
    FPort: TIdPort;
    FIPVersion : TIdIPVersion;
    FUsername: String;
    {$IFDEF USE_OBJECT_ARC}[Weak]{$ENDIF} FChainedProxy: TIdCustomTransparentProxy;
    //
    procedure InitComponent; override;
    function  GetEnabled: Boolean; virtual; abstract;
    procedure SetEnabled(AValue: Boolean); virtual;
    procedure MakeConnection(AIOHandler: TIdIOHandler; const AHost: string; const APort: TIdPort; const AIPVersion: TIdIPVersion = ID_DEFAULT_IP_VERSION); virtual; abstract;
    {$IFNDEF USE_OBJECT_ARC}
    procedure Notification(AComponent: TComponent; Operation: TOperation); override;
    {$ENDIF}
    procedure SetChainedProxy(const AValue: TIdCustomTransparentProxy);
  public
    procedure Assign(ASource: TPersistent); override;
    procedure OpenUDP(AHandle : TIdSocketHandle; const AHost: string = ''; const APort: TIdPort = 0; const AIPVersion: TIdIPVersion = ID_DEFAULT_IP_VERSION); virtual;
    procedure CloseUDP(AHandle: TIdSocketHandle); virtual;
    function RecvFromUDP(AHandle: TIdSocketHandle; var ABuffer : TIdBytes;
      var VPeerIP: string; var VPeerPort: TIdPort; var VIPVersion: TIdIPVersion;
       AMSec: Integer = IdTimeoutDefault): Integer; virtual;
    procedure SendToUDP(AHandle: TIdSocketHandle;
      const AHost: string; const APort: TIdPort; const AIPVersion: TIdIPVersion;
      const ABuffer : TIdBytes); virtual;
    procedure Connect(AIOHandler: TIdIOHandler; const AHost: string; const APort: TIdPort; const AIPVersion: TIdIPVersion = ID_DEFAULT_IP_VERSION);
    //
    procedure Bind(AIOHandler: TIdIOHandler; const AHost: string; const APort: TIdPort; const AIPVersion: TIdIPVersion = ID_DEFAULT_IP_VERSION);overload;virtual;
    procedure Bind(AIOHandler: TIdIOHandler; const APort: TIdPort); overload;
    function  Listen(AIOHandler: TIdIOHandler; const ATimeOut: Integer): Boolean; virtual;
    //
    property  Enabled: Boolean read GetEnabled write SetEnabled;
    property  Host: String read FHost write FHost;
    property  Password: String read FPassword write FPassword;
    property  Port: TIdPort read FPort write FPort;
    property  IPVersion : TIdIPVersion read FIPVersion write FIPVersion default ID_DEFAULT_IP_VERSION;
    property  Username: String read FUsername write FUsername;
    property  ChainedProxy: TIdCustomTransparentProxy read FChainedProxy write SetChainedProxy;
  end;

implementation

uses
  IdResourceStringsCore, IdExceptionCore;

{ TIdCustomTransparentProxy }

procedure TIdCustomTransparentProxy.InitComponent;
begin
  inherited;
  FIPVersion := ID_DEFAULT_IP_VERSION;
end;

procedure TIdCustomTransparentProxy.Assign(ASource: TPersistent);
var
  LSource: TIdCustomTransparentProxy;
Begin
  if ASource is TIdCustomTransparentProxy then begin
    LSource := TIdCustomTransparentProxy(ASource);
    FHost := LSource.Host;
    FPassword := LSource.Password;
    FPort := LSource.Port;
    FIPVersion := LSource.IPVersion;
    FUsername := LSource.Username;
  end else begin
    inherited Assign(ASource);
  end;
End;//

procedure TIdCustomTransparentProxy.Connect(AIOHandler: TIdIOHandler; const AHost: string; const APort: TIdPort; const AIPVersion: TIdIPVersion = ID_DEFAULT_IP_VERSION);
var
  // under ARC, convert a weak reference to a strong reference before working with it
  LChainedProxy: TIdCustomTransparentProxy;
begin
  LChainedProxy := FChainedProxy;
  if Assigned(LChainedProxy) and LChainedProxy.Enabled then begin
    MakeConnection(AIOHandler, LChainedProxy.Host, LChainedProxy.Port);
    LChainedProxy.Connect(AIOHandler, AHost, APort, AIPVersion);
  end else begin
    MakeConnection(AIOHandler, AHost, APort, AIPVersion);
  end;
end;

procedure RaiseProxyBindError;
  {$IFDEF USE_NORETURN}noreturn;{$ENDIF}
begin
  raise EIdTransparentProxyCantBind.Create(RSTransparentProxyCannotBind);
end;

function TIdCustomTransparentProxy.Listen(AIOHandler: TIdIOHandler; const ATimeOut: integer):boolean;
begin
  {$IFNDEF USE_NORETURN}
  Result := False; // keep the compiler happy
  {$ENDIF}
  RaiseProxyBindError;
end;

procedure TIdCustomTransparentProxy.Bind(AIOHandler: TIdIOHandler; const AHost: string; const APort: TIdPort; const AIPVersion: TIdIPVersion = ID_DEFAULT_IP_VERSION);
begin
  RaiseProxyBindError;
end;

procedure TIdCustomTransparentProxy.Bind(AIOHandler: TIdIOHandler; const APort: TIdPort);
begin
  Bind(AIOHandler, '0.0.0.0', APort);   {do not localize}
end;

procedure TIdCustomTransparentProxy.SetEnabled(AValue: Boolean);
Begin
End;

// under ARC, all weak references to a freed object get nil'ed automatically
{$IFNDEF USE_OBJECT_ARC}
procedure TIdCustomTransparentProxy.Notification(AComponent: TComponent; Operation: TOperation);
begin
  if (Operation = opRemove) and (AComponent = FChainedProxy) then begin
    FChainedProxy := nil;
  end;
  inherited Notification(AComponent,Operation);
end;
{$ENDIF}

procedure TIdCustomTransparentProxy.SetChainedProxy(const AValue: TIdCustomTransparentProxy);
var
  LNextValue: TIdCustomTransparentProxy;
  // under ARC, convert a weak reference to a strong reference before working with it
  LChainedProxy: TIdCustomTransparentProxy;
begin
  LChainedProxy := FChainedProxy;

  if LChainedProxy <> AValue then
  begin
    LNextValue := AValue;
    while Assigned(LNextValue) do begin
      if LNextValue = Self then begin
        raise EIdTransparentProxyCircularLink.CreateFmt(RSInterceptCircularLink, [ClassName]);// -> One EIDCircularLink exception
      end;
      LNextValue := LNextValue.ChainedProxy;
    end;

    // under ARC, all weak references to a freed object get nil'ed automatically

    {$IFNDEF USE_OBJECT_ARC}
    if Assigned(LChainedProxy) then begin
      LChainedProxy.RemoveFreeNotification(Self);
    end;
    {$ENDIF}

    FChainedProxy := AValue;

    {$IFNDEF USE_OBJECT_ARC}
    if Assigned(AValue) then begin
      AValue.FreeNotification(Self);
    end;
    {$ENDIF}
  end;
end;

procedure RaiseUDPNotSupportedError;
  {$IFDEF USE_NORETURN}noreturn;{$ENDIF}
begin
  raise EIdTransparentProxyUDPNotSupported.Create(RSTransparentProxyCanNotSupportUDP);
end;

procedure TIdCustomTransparentProxy.CloseUDP(AHandle: TIdSocketHandle);
begin
  RaiseUDPNotSupportedError;
end;

procedure TIdCustomTransparentProxy.OpenUDP(AHandle: TIdSocketHandle;
  const AHost: string = ''; const APort: TIdPort = 0;
  const AIPVersion: TIdIPVersion = ID_DEFAULT_IP_VERSION);
begin
  RaiseUDPNotSupportedError;;
end;

function TIdCustomTransparentProxy.RecvFromUDP(AHandle: TIdSocketHandle;
  var ABuffer : TIdBytes; var VPeerIP: string; var VPeerPort: TIdPort;
  var VIPVersion: TIdIPVersion; AMSec: Integer = IdTimeoutDefault): Integer;
begin
  {$IFNDEF USE_NORETURN}
  Result := 0; // keep the compiler happy
  {$ENDIF}
  RaiseUDPNotSupportedError;
end;

procedure TIdCustomTransparentProxy.SendToUDP(AHandle: TIdSocketHandle;
  const AHost: string; const APort: TIdPort; const AIPVersion: TIdIPVersion;
  const ABuffer : TIdBytes);
begin
  RaiseUDPNotSupportedError;
end;

end.