/blcksock.pas

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{==============================================================================|

| Project : Ararat Synapse                                       | 009.009.000 |

|==============================================================================|

| Content: Library base                                                        |

|==============================================================================|

| Copyright (c)1999-2012, Lukas Gebauer                                        |

| All rights reserved.                                                         |

|                                                                              |

| Redistribution and use in source and binary forms, with or without           |

| modification, are permitted provided that the following conditions are met:  |

|                                                                              |

| Redistributions of source code must retain the above copyright notice, this  |

| list of conditions and the following disclaimer.                             |

|                                                                              |

| Redistributions in binary form must reproduce the above copyright notice,    |

| this list of conditions and the following disclaimer in the documentation    |

| and/or other materials provided with the distribution.                       |

|                                                                              |

| Neither the name of Lukas Gebauer nor the names of its contributors may      |

| be used to endorse or promote products derived from this software without    |

| specific prior written permission.                                           |

|                                                                              |

| THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"  |

| AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE    |

| IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE   |

| ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR  |

| ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL       |

| DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR   |

| SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER   |

| CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT           |

| LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY    |

| OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH  |

| DAMAGE.                                                                      |

|==============================================================================|

| The Initial Developer of the Original Code is Lukas Gebauer (Czech Republic).|

| Portions created by Lukas Gebauer are Copyright (c)1999-2012.                |

| All Rights Reserved.                                                         |

|==============================================================================|

| Contributor(s):                                                              |

|==============================================================================|

| History: see HISTORY.HTM from distribution package                           |

|          (Found at URL: http://www.ararat.cz/synapse/)                       |

|==============================================================================}



{

Special thanks to Gregor Ibic <gregor.ibic@intelicom.si>

 (Intelicom d.o.o., http://www.intelicom.si)

 for good inspiration about SSL programming.

}



{$DEFINE ONCEWINSOCK}

{Note about define ONCEWINSOCK:

If you remove this compiler directive, then socket interface is loaded and

initialized on constructor of TBlockSocket class for each socket separately.

Socket interface is used only if your need it.



If you leave this directive here, then socket interface is loaded and

initialized only once at start of your program! It boost performace on high

count of created and destroyed sockets. It eliminate possible small resource

leak on Windows systems too.

}



//{$DEFINE RAISEEXCEPT}

{When you enable this define, then is Raiseexcept property is on by default

}



{:@abstract(Synapse's library core)



Core with implementation basic socket classes.

}



{$IFDEF FPC}

  {$MODE DELPHI}

{$ENDIF}

{$IFDEF VER125}

  {$DEFINE BCB}

{$ENDIF}

{$IFDEF BCB}

  {$ObjExportAll On}

{$ENDIF}

{$Q-}

{$H+}

{$M+}

{$TYPEDADDRESS OFF}





//old Delphi does not have MSWINDOWS define.

{$IFDEF WIN32}

  {$IFNDEF MSWINDOWS}

    {$DEFINE MSWINDOWS}

  {$ENDIF}

{$ENDIF}



{$IFDEF UNICODE}

  {$WARN IMPLICIT_STRING_CAST OFF}

  {$WARN IMPLICIT_STRING_CAST_LOSS OFF}

{$ENDIF}



unit blcksock;



interface



uses

  SysUtils, Classes,

  synafpc,

  synsock, synautil, synacode, synaip

{$IFDEF CIL}

  ,System.Net

  ,System.Net.Sockets

  ,System.Text

{$ENDIF}

  ;



const



  SynapseRelease = '40';



  cLocalhost = '127.0.0.1';

  cAnyHost = '0.0.0.0';

  cBroadcast = '255.255.255.255';

  c6Localhost = '::1';

  c6AnyHost = '::0';

  c6Broadcast = 'ffff::1';

  cAnyPort = '0';

  CR = #$0d;

  LF = #$0a;

  CRLF = CR + LF;

  c64k = 65536;



type



  {:@abstract(Exception clas used by Synapse)

   When you enable generating of exceptions, this exception is raised by

   Synapse's units.}

  ESynapseError = class(Exception)

  private

    FErrorCode: Integer;

    FErrorMessage: string;

  published

    {:Code of error. Value depending on used operating system}

    property ErrorCode: Integer read FErrorCode Write FErrorCode;

    {:Human readable description of error.}

    property ErrorMessage: string read FErrorMessage Write FErrorMessage;

  end;



  {:Types of OnStatus events}

  THookSocketReason = (

    {:Resolving is begin. Resolved IP and port is in parameter in format like:

     'localhost.somewhere.com:25'.}

    HR_ResolvingBegin,

    {:Resolving is done. Resolved IP and port is in parameter in format like:

     'localhost.somewhere.com:25'. It is always same as in HR_ResolvingBegin!}

    HR_ResolvingEnd,

    {:Socket created by CreateSocket method. It reporting Family of created

     socket too!}

    HR_SocketCreate,

    {:Socket closed by CloseSocket method.}

    HR_SocketClose,

    {:Socket binded to IP and Port. Binded IP and Port is in parameter in format

     like: 'localhost.somewhere.com:25'.}

    HR_Bind,

    {:Socket connected to IP and Port. Connected IP and Port is in parameter in

     format like: 'localhost.somewhere.com:25'.}

    HR_Connect,

    {:Called when CanRead method is used with @True result.}

    HR_CanRead,

    {:Called when CanWrite method is used with @True result.}

    HR_CanWrite,

    {:Socket is swithed to Listen mode. (TCP socket only)}

    HR_Listen,

    {:Socket Accepting client connection. (TCP socket only)}

    HR_Accept,

    {:report count of bytes readed from socket. Number is in parameter string.

     If you need is in integer, you must use StrToInt function!}

    HR_ReadCount,

    {:report count of bytes writed to socket. Number is in parameter string. If

     you need is in integer, you must use StrToInt function!}

    HR_WriteCount,

    {:If is limiting of bandwidth on, then this reason is called when sending or

     receiving is stopped for satisfy bandwidth limit. Parameter is count of

     waiting milliseconds.}

    HR_Wait,

    {:report situation where communication error occured. When raiseexcept is

     @true, then exception is called after this Hook reason.}

    HR_Error

    );



  {:Procedural type for OnStatus event. Sender is calling TBlockSocket object,

   Reason is one of set Status events and value is optional data.}

  THookSocketStatus = procedure(Sender: TObject; Reason: THookSocketReason;

    const Value: String) of object;



  {:This procedural type is used for DataFilter hooks.}

  THookDataFilter = procedure(Sender: TObject; var Value: AnsiString) of object;



  {:This procedural type is used for hook OnCreateSocket. By this hook you can

   insert your code after initialisation of socket. (you can set special socket

   options, etc.)}

  THookCreateSocket = procedure(Sender: TObject) of object;



  {:This procedural type is used for monitoring of communication.}

  THookMonitor = procedure(Sender: TObject; Writing: Boolean;

    const Buffer: TMemory; Len: Integer) of object;



  {:This procedural type is used for hook OnAfterConnect. By this hook you can

   insert your code after TCP socket has been sucessfully connected.}

  THookAfterConnect = procedure(Sender: TObject) of object;



  {:This procedural type is used for hook OnVerifyCert. By this hook you can

   insert your additional certificate verification code. Usefull to verify server

   CN against URL. }



  THookVerifyCert = function(Sender: TObject):boolean of object;



 {:This procedural type is used for hook OnHeartbeat. By this hook you can

   call your code repeately during long socket operations.

   You must enable heartbeats by @Link(HeartbeatRate) property!}

  THookHeartbeat = procedure(Sender: TObject) of object;



  {:Specify family of socket.}

  TSocketFamily = (

    {:Default mode. Socket family is defined by target address for connection.

     It allows instant access to IPv4 and IPv6 nodes. When you need IPv6 address

     as destination, then is used IPv6 mode. othervise is used IPv4 mode.

     However this mode not working properly with preliminary IPv6 supports!}

    SF_Any,

    {:Turn this class to pure IPv4 mode. This mode is totally compatible with

     previous Synapse releases.}

    SF_IP4,

    {:Turn to only IPv6 mode.}

    SF_IP6

    );



  {:specify possible values of SOCKS modes.}

  TSocksType = (

    ST_Socks5,

    ST_Socks4

    );



  {:Specify requested SSL/TLS version for secure connection.}

  TSSLType = (

    LT_all,

    LT_SSLv2,

    LT_SSLv3,

    LT_TLSv1,

    LT_TLSv1_1,

    LT_SSHv2

    );



  {:Specify type of socket delayed option.}

  TSynaOptionType = (

    SOT_Linger,

    SOT_RecvBuff,

    SOT_SendBuff,

    SOT_NonBlock,

    SOT_RecvTimeout,

    SOT_SendTimeout,

    SOT_Reuse,

    SOT_TTL,

    SOT_Broadcast,

    SOT_MulticastTTL,

    SOT_MulticastLoop

    );



  {:@abstract(this object is used for remember delayed socket option set.)}

  TSynaOption = class(TObject)

  public

    Option: TSynaOptionType;

    Enabled: Boolean;

    Value: Integer;

  end;



  TCustomSSL = class;

  TSSLClass = class of TCustomSSL;



  {:@abstract(Basic IP object.)

   This is parent class for other class with protocol implementations. Do not

   use this class directly! Use @link(TICMPBlockSocket), @link(TRAWBlockSocket),

   @link(TTCPBlockSocket) or @link(TUDPBlockSocket) instead.}

  TBlockSocket = class(TObject)

  private

    FOnStatus: THookSocketStatus;

    FOnReadFilter: THookDataFilter;

    FOnCreateSocket: THookCreateSocket;

    FOnMonitor: THookMonitor;

    FOnHeartbeat: THookHeartbeat;

    FLocalSin: TVarSin;

    FRemoteSin: TVarSin;

    FTag: integer;

    FBuffer: AnsiString;

    FRaiseExcept: Boolean;

    FNonBlockMode: Boolean;

    FMaxLineLength: Integer;

    FMaxSendBandwidth: Integer;

    FNextSend: LongWord;

    FMaxRecvBandwidth: Integer;

    FNextRecv: LongWord;

    FConvertLineEnd: Boolean;

    FLastCR: Boolean;

    FLastLF: Boolean;

    FBinded: Boolean;

    FFamily: TSocketFamily;

    FFamilySave: TSocketFamily;

    FIP6used: Boolean;

    FPreferIP4: Boolean;

    FDelayedOptions: TList;

    FInterPacketTimeout: Boolean;

    {$IFNDEF CIL}

    FFDSet: TFDSet;

    {$ENDIF}

    FRecvCounter: Integer;

    FSendCounter: Integer;

    FSendMaxChunk: Integer;

    FStopFlag: Boolean;

    FNonblockSendTimeout: Integer;

    FHeartbeatRate: integer;

    FConnectionTimeout: integer;

    {$IFNDEF ONCEWINSOCK}

    FWsaDataOnce: TWSADATA;

    {$ENDIF}

    function GetSizeRecvBuffer: Integer;

    procedure SetSizeRecvBuffer(Size: Integer);

    function GetSizeSendBuffer: Integer;

    procedure SetSizeSendBuffer(Size: Integer);

    procedure SetNonBlockMode(Value: Boolean);

    procedure SetTTL(TTL: integer);

    function GetTTL:integer;

    procedure SetFamily(Value: TSocketFamily); virtual;

    procedure SetSocket(Value: TSocket); virtual;

    function GetWsaData: TWSAData;

    function FamilyToAF(f: TSocketFamily): TAddrFamily;

  protected

    FSocket: TSocket;

    FLastError: Integer;

    FLastErrorDesc: string;

    FOwner: TObject;

    procedure SetDelayedOption(const Value: TSynaOption);

    procedure DelayedOption(const Value: TSynaOption);

    procedure ProcessDelayedOptions;

    procedure InternalCreateSocket(Sin: TVarSin);

    procedure SetSin(var Sin: TVarSin; IP, Port: string);

    function GetSinIP(Sin: TVarSin): string;

    function GetSinPort(Sin: TVarSin): Integer;

    procedure DoStatus(Reason: THookSocketReason; const Value: string);

    procedure DoReadFilter(Buffer: TMemory; var Len: Integer);

    procedure DoMonitor(Writing: Boolean; const Buffer: TMemory; Len: Integer);

    procedure DoCreateSocket;

    procedure DoHeartbeat;

    procedure LimitBandwidth(Length: Integer; MaxB: integer; var Next: LongWord);

    procedure SetBandwidth(Value: Integer);

    function TestStopFlag: Boolean;

    procedure InternalSendStream(const Stream: TStream; WithSize, Indy: boolean); virtual;

    function InternalCanRead(Timeout: Integer): Boolean; virtual;

  public

    constructor Create;



    {:Create object and load all necessary socket library. What library is

     loaded is described by STUB parameter. If STUB is empty string, then is

     loaded default libraries.}

    constructor CreateAlternate(Stub: string);

    destructor Destroy; override;



    {:If @link(family) is not SF_Any, then create socket with type defined in

     @link(Family) property. If family is SF_Any, then do nothing! (socket is

     created automaticly when you know what type of socket you need to create.

     (i.e. inside @link(Connect) or @link(Bind) call.) When socket is created,

     then is aplyed all stored delayed socket options.}

    procedure CreateSocket;



    {:It create socket. Address resolving of Value tells what type of socket is

     created. If Value is resolved as IPv4 IP, then is created IPv4 socket. If

     value is resolved as IPv6 address, then is created IPv6 socket.}

    procedure CreateSocketByName(const Value: String);



    {:Destroy socket in use. This method is also automatically called from

     object destructor.}

    procedure CloseSocket; virtual;



    {:Abort any work on Socket and destroy them.}

    procedure AbortSocket; virtual;



    {:Connects socket to local IP address and PORT. IP address may be numeric or

     symbolic ('192.168.74.50', 'cosi.nekde.cz', 'ff08::1'). The same for PORT

     - it may be number or mnemonic port ('23', 'telnet').



     If port value is '0', system chooses itself and conects unused port in the

     range 1024 to 4096 (this depending by operating system!). Structure

     LocalSin is filled after calling this method.



     Note: If you call this on non-created socket, then socket is created

     automaticly.



     Warning: when you call : Bind('0.0.0.0','0'); then is nothing done! In this

     case is used implicit system bind instead.}

    procedure Bind(IP, Port: string);



    {:Connects socket to remote IP address and PORT. The same rules as with

     @link(BIND) method are valid. The only exception is that PORT with 0 value

     will not be connected!



     Structures LocalSin and RemoteSin will be filled with valid values.



     When you call this on non-created socket, then socket is created

     automaticly. Type of created socket is by @link(Family) property. If is

     used SF_IP4, then is created socket for IPv4. If is used SF_IP6, then is

     created socket for IPv6. When you have family on SF_Any (default!), then

     type of created socket is determined by address resolving of destination

     address. (Not work properly on prilimitary winsock IPv6 support!)}

    procedure Connect(IP, Port: string); virtual;



    {:Sets socket to receive mode for new incoming connections. It is necessary

     to use @link(TBlockSocket.BIND) function call before this method to select

     receiving port!}

    procedure Listen; virtual;



    {:Waits until new incoming connection comes. After it comes a new socket is

     automatically created (socket handler is returned by this function as

     result).}

    function Accept: TSocket; virtual;



    {:Sends data of LENGTH from BUFFER address via connected socket. System

     automatically splits data to packets.}

    function SendBuffer(Buffer: Tmemory; Length: Integer): Integer; virtual;



    {:One data BYTE is sent via connected socket.}

    procedure SendByte(Data: Byte); virtual;



    {:Send data string via connected socket. Any terminator is not added! If you

     need send true string with CR-LF termination, you must add CR-LF characters

     to sended string! Because any termination is not added automaticly, you can

     use this function for sending any binary data in binary string.}

    procedure SendString(Data: AnsiString); virtual;



    {:Send integer as four bytes to socket.}

    procedure SendInteger(Data: integer); virtual;



    {:Send data as one block to socket. Each block begin with 4 bytes with

     length of data in block. This 4 bytes is added automaticly by this

     function.}

    procedure SendBlock(const Data: AnsiString); virtual;



    {:Send data from stream to socket.}

    procedure SendStreamRaw(const Stream: TStream); virtual;



    {:Send content of stream to socket. It using @link(SendBlock) method}

    procedure SendStream(const Stream: TStream); virtual;



    {:Send content of stream to socket. It using @link(SendBlock) method and

    this is compatible with streams in Indy library.}

    procedure SendStreamIndy(const Stream: TStream); virtual;



    {:Note: This is low-level receive function. You must be sure if data is

     waiting for read before call this function for avoid deadlock!



     Waits until allocated buffer is filled by received data. Returns number of

     data received, which equals to LENGTH value under normal operation. If it

     is not equal the communication channel is possibly broken.



     On stream oriented sockets if is received 0 bytes, it mean 'socket is

     closed!"



     On datagram socket is readed first waiting datagram.}

    function RecvBuffer(Buffer: TMemory; Length: Integer): Integer; virtual;



    {:Note: This is high-level receive function. It using internal

     @link(LineBuffer) and you can combine this function freely with other

     high-level functions!



     Method waits until data is received. If no data is received within TIMEOUT

     (in milliseconds) period, @link(LastError) is set to WSAETIMEDOUT. Methods

     serves for reading any size of data (i.e. one megabyte...). This method is

     preffered for reading from stream sockets (like TCP).}

    function RecvBufferEx(Buffer: Tmemory; Len: Integer;

      Timeout: Integer): Integer; virtual;



    {:Similar to @link(RecvBufferEx), but readed data is stored in binary

     string, not in memory buffer.}

    function RecvBufferStr(Len: Integer; Timeout: Integer): AnsiString; virtual;



    {:Note: This is high-level receive function. It using internal

     @link(LineBuffer) and you can combine this function freely with other

     high-level functions.



     Waits until one data byte is received which is also returned as function

     result. If no data is received within TIMEOUT (in milliseconds)period,

     @link(LastError) is set to WSAETIMEDOUT and result have value 0.}

    function RecvByte(Timeout: Integer): Byte; virtual;



    {:Note: This is high-level receive function. It using internal

     @link(LineBuffer) and you can combine this function freely with other

     high-level functions.



     Waits until one four bytes are received and return it as one Ineger Value.

     If no data is received within TIMEOUT (in milliseconds)period,

     @link(LastError) is set to WSAETIMEDOUT and result have value 0.}

    function RecvInteger(Timeout: Integer): Integer; virtual;



    {:Note: This is high-level receive function. It using internal

     @link(LineBuffer) and you can combine this function freely with other

     high-level functions.



     Method waits until data string is received. This string is terminated by

     CR-LF characters. The resulting string is returned without this termination

     (CR-LF)! If @link(ConvertLineEnd) is used, then CR-LF sequence may not be

     exactly CR-LF. See @link(ConvertLineEnd) description. If no data is

     received within TIMEOUT (in milliseconds) period, @link(LastError) is set

     to WSAETIMEDOUT. You may also specify maximum length of reading data by

     @link(MaxLineLength) property.}

    function RecvString(Timeout: Integer): AnsiString; virtual;



    {:Note: This is high-level receive function. It using internal

     @link(LineBuffer) and you can combine this function freely with other

     high-level functions.



     Method waits until data string is received. This string is terminated by

     Terminator string. The resulting string is returned without this

     termination. If no data is received within TIMEOUT (in milliseconds)

     period, @link(LastError) is set to WSAETIMEDOUT. You may also specify

     maximum length of reading data by @link(MaxLineLength) property.}

    function RecvTerminated(Timeout: Integer; const Terminator: AnsiString): AnsiString; virtual;



    {:Note: This is high-level receive function. It using internal

     @link(LineBuffer) and you can combine this function freely with other

     high-level functions.



     Method reads all data waiting for read. If no data is received within

     TIMEOUT (in milliseconds) period, @link(LastError) is set to WSAETIMEDOUT.

     Methods serves for reading unknown size of data. Because before call this

     function you don't know size of received data, returned data is stored in

     dynamic size binary string. This method is preffered for reading from

     stream sockets (like TCP). It is very goot for receiving datagrams too!

     (UDP protocol)}

    function RecvPacket(Timeout: Integer): AnsiString; virtual;



    {:Read one block of data from socket. Each block begin with 4 bytes with

     length of data in block. This function read first 4 bytes for get lenght,

     then it wait for reported count of bytes.}

    function RecvBlock(Timeout: Integer): AnsiString; virtual;



    {:Read all data from socket to stream until socket is closed (or any error

     occured.)}

    procedure RecvStreamRaw(const Stream: TStream; Timeout: Integer); virtual;

    {:Read requested count of bytes from socket to stream.}

    procedure RecvStreamSize(const Stream: TStream; Timeout: Integer; Size: Integer);



    {:Receive data to stream. It using @link(RecvBlock) method.}

    procedure RecvStream(const Stream: TStream; Timeout: Integer); virtual;



    {:Receive data to stream. This function is compatible with similar function

    in Indy library. It using @link(RecvBlock) method.}

    procedure RecvStreamIndy(const Stream: TStream; Timeout: Integer); virtual;



    {:Same as @link(RecvBuffer), but readed data stays in system input buffer.

    Warning: this function not respect data in @link(LineBuffer)! Is not

    recommended to use this function!}

    function PeekBuffer(Buffer: TMemory; Length: Integer): Integer; virtual;



    {:Same as @link(RecvByte), but readed data stays in input system buffer.

     Warning: this function not respect data in @link(LineBuffer)! Is not

    recommended to use this function!}

    function PeekByte(Timeout: Integer): Byte; virtual;



    {:On stream sockets it returns number of received bytes waiting for picking.

     0 is returned when there is no such data. On datagram socket it returns

     length of the first waiting datagram. Returns 0 if no datagram is waiting.}

    function WaitingData: Integer; virtual;



    {:Same as @link(WaitingData), but if exists some of data in @link(Linebuffer),

     return their length instead.}

    function WaitingDataEx: Integer;



    {:Clear all waiting data for read from buffers.}

    procedure Purge;



    {:Sets linger. Enabled linger means that the system waits another LINGER

     (in milliseconds) time for delivery of sent data. This function is only for

     stream type of socket! (TCP)}

    procedure SetLinger(Enable: Boolean; Linger: Integer);



    {:Actualize values in @link(LocalSin).}

    procedure GetSinLocal;



    {:Actualize values in @link(RemoteSin).}

    procedure GetSinRemote;



    {:Actualize values in @link(LocalSin) and @link(RemoteSin).}

    procedure GetSins;



    {:Reset @link(LastError) and @link(LastErrorDesc) to non-error state.}

    procedure ResetLastError;



    {:If you "manually" call Socket API functions, forward their return code as

     parameter to this function, which evaluates it, eventually calls

     GetLastError and found error code returns and stores to @link(LastError).}

    function SockCheck(SockResult: Integer): Integer; virtual;



    {:If @link(LastError) contains some error code and @link(RaiseExcept)

     property is @true, raise adequate exception.}

    procedure ExceptCheck;



    {:Returns local computer name as numerical or symbolic value. It try get

     fully qualified domain name. Name is returned in the format acceptable by

     functions demanding IP as input parameter.}

    function LocalName: string;



    {:Try resolve name to all possible IP address. i.e. If you pass as name

     result of @link(LocalName) method, you get all IP addresses used by local

     system.}

    procedure ResolveNameToIP(Name: string; const IPList: TStrings);



    {:Try resolve name to primary IP address. i.e. If you pass as name result of

     @link(LocalName) method, you get primary IP addresses used by local system.}

    function ResolveName(Name: string): string;



    {:Try resolve IP to their primary domain name. If IP not have domain name,

     then is returned original IP.}

    function ResolveIPToName(IP: string): string;



    {:Try resolve symbolic port name to port number. (i.e. 'Echo' to 8)}

    function ResolvePort(Port: string): Word;



    {:Set information about remote side socket. It is good for seting remote

     side for sending UDP packet, etc.}

    procedure SetRemoteSin(IP, Port: string);



    {:Picks IP socket address from @link(LocalSin).}

    function GetLocalSinIP: string; virtual;



    {:Picks IP socket address from @link(RemoteSin).}

    function GetRemoteSinIP: string; virtual;



    {:Picks socket PORT number from @link(LocalSin).}

    function GetLocalSinPort: Integer; virtual;



    {:Picks socket PORT number from @link(RemoteSin).}

    function GetRemoteSinPort: Integer; virtual;



    {:Return @TRUE, if you can read any data from socket or is incoming

     connection on TCP based socket. Status is tested for time Timeout (in

     milliseconds). If value in Timeout is 0, status is only tested and

     continue. If value in Timeout is -1, run is breaked and waiting for read

     data maybe forever.



     This function is need only on special cases, when you need use

     @link(RecvBuffer) function directly! read functioms what have timeout as

     calling parameter, calling this function internally.}

    function CanRead(Timeout: Integer): Boolean; virtual;



    {:Same as @link(CanRead), but additionally return @TRUE if is some data in

     @link(LineBuffer).}

    function CanReadEx(Timeout: Integer): Boolean; virtual;



    {:Return @TRUE, if you can to socket write any data (not full sending

     buffer). Status is tested for time Timeout (in milliseconds). If value in

     Timeout is 0, status is only tested and continue. If value in Timeout is

     -1, run is breaked and waiting for write data maybe forever.



     This function is need only on special cases!}

    function CanWrite(Timeout: Integer): Boolean; virtual;



    {:Same as @link(SendBuffer), but send datagram to address from

     @link(RemoteSin). Usefull for sending reply to datagram received by

     function @link(RecvBufferFrom).}

    function SendBufferTo(Buffer: TMemory; Length: Integer): Integer; virtual;



    {:Note: This is low-lever receive function. You must be sure if data is

     waiting for read before call this function for avoid deadlock!



     Receives first waiting datagram to allocated buffer. If there is no waiting

     one, then waits until one comes. Returns length of datagram stored in

     BUFFER. If length exceeds buffer datagram is truncated. After this

     @link(RemoteSin) structure contains information about sender of UDP packet.}

    function RecvBufferFrom(Buffer: TMemory; Length: Integer): Integer; virtual;

{$IFNDEF CIL}

    {:This function is for check for incoming data on set of sockets. Whitch

    sockets is checked is decribed by SocketList Tlist with TBlockSocket

    objects. TList may have maximal number of objects defined by FD_SETSIZE

    constant. Return @TRUE, if you can from some socket read any data or is

    incoming connection on TCP based socket. Status is tested for time Timeout

    (in milliseconds). If value in Timeout is 0, status is only tested and

    continue. If value in Timeout is -1, run is breaked and waiting for read

    data maybe forever. If is returned @TRUE, CanReadList TList is filled by all

    TBlockSocket objects what waiting for read.}

    function GroupCanRead(const SocketList: TList; Timeout: Integer;

      const CanReadList: TList): Boolean;

{$ENDIF}

    {:By this method you may turn address reuse mode for local @link(bind). It

     is good specially for UDP protocol. Using this with TCP protocol is

     hazardous!}

    procedure EnableReuse(Value: Boolean);



    {:Try set timeout for all sending and receiving operations, if socket

     provider can do it. (It not supported by all socket providers!)}

    procedure SetTimeout(Timeout: Integer);



    {:Try set timeout for all sending operations, if socket provider can do it.

     (It not supported by all socket providers!)}

    procedure SetSendTimeout(Timeout: Integer);



    {:Try set timeout for all receiving operations, if socket provider can do

     it. (It not supported by all socket providers!)}

    procedure SetRecvTimeout(Timeout: Integer);



    {:Return value of socket type.}

    function GetSocketType: integer; Virtual;



    {:Return value of protocol type for socket creation.}

    function GetSocketProtocol: integer; Virtual;



    {:WSA structure with information about socket provider. On non-windows 

     platforms this structure is simulated!}

    property WSAData: TWSADATA read GetWsaData;



    {:FDset structure prepared for usage with this socket.}

    property FDset: TFDSet read FFDset;



    {:Structure describing local socket side.}

    property LocalSin: TVarSin read FLocalSin write FLocalSin;



    {:Structure describing remote socket side.}

    property RemoteSin: TVarSin read FRemoteSin write FRemoteSin;



    {:Socket handler. Suitable for "manual" calls to socket API or manual

     connection of socket to a previously created socket (i.e by Accept method

     on TCP socket)}

    property Socket: TSocket read FSocket write SetSocket;



    {:Last socket operation error code. Error codes are described in socket

     documentation. Human readable error description is stored in

     @link(LastErrorDesc) property.}

    property LastError: Integer read FLastError;



    {:Human readable error description of @link(LastError) code.}

    property LastErrorDesc: string read FLastErrorDesc;



    {:Buffer used by all high-level receiving functions. This buffer is used for

     optimized reading of data from socket. In normal cases you not need access

     to this buffer directly!}

    property LineBuffer: AnsiString read FBuffer write FBuffer;



    {:Size of Winsock receive buffer. If it is not supported by socket provider,

     it return as size one kilobyte.}

    property SizeRecvBuffer: Integer read GetSizeRecvBuffer write SetSizeRecvBuffer;



    {:Size of Winsock send buffer. If it is not supported by socket provider, it

     return as size one kilobyte.}

    property SizeSendBuffer: Integer read GetSizeSendBuffer write SetSizeSendBuffer;



    {:If @True, turn class to non-blocking mode. Not all functions are working

     properly in this mode, you must know exactly what you are doing! However

     when you have big experience with non-blocking programming, then you can

     optimise your program by non-block mode!}

    property NonBlockMode: Boolean read FNonBlockMode Write SetNonBlockMode;



    {:Set Time-to-live value. (if system supporting it!)}

    property TTL: Integer read GetTTL Write SetTTL;



    {:If is @true, then class in in IPv6 mode.}

    property IP6used: Boolean read FIP6used;



    {:Return count of received bytes on this socket from begin of current

     connection.}

    property RecvCounter: Integer read FRecvCounter;



    {:Return count of sended bytes on this socket from begin of current

     connection.}

    property SendCounter: Integer read FSendCounter;

  published

    {:Return descriptive string for given error code. This is class function.

     You may call it without created object!}

    class function GetErrorDesc(ErrorCode: Integer): string;



    {:Return descriptive string for @link(LastError).}

    function GetErrorDescEx: string; virtual;



    {:this value is for free use.}

    property Tag: Integer read FTag write FTag;



    {:If @true, winsock errors raises exception. Otherwise is setted

    @link(LastError) value only and you must check it from your program! Default

    value is @false.}

    property RaiseExcept: Boolean read FRaiseExcept write FRaiseExcept;



    {:Define maximum length in bytes of @link(LineBuffer) for high-level

     receiving functions. If this functions try to read more data then this

     limit, error is returned! If value is 0 (default), no limitation is used.

     This is very good protection for stupid attacks to your server by sending

     lot of data without proper terminator... until all your memory is allocated

     by LineBuffer!



     Note: This maximum length is checked only in functions, what read unknown

     number of bytes! (like @link(RecvString) or @link(RecvTerminated))}

    property MaxLineLength: Integer read FMaxLineLength Write FMaxLineLength;



    {:Define maximal bandwidth for all sending operations in bytes per second.

     If value is 0 (default), bandwidth limitation is not used.}

    property MaxSendBandwidth: Integer read FMaxSendBandwidth Write FMaxSendBandwidth;



    {:Define maximal bandwidth for all receiving operations in bytes per second.

     If value is 0 (default), bandwidth limitation is not used.}

    property MaxRecvBandwidth: Integer read FMaxRecvBandwidth Write FMaxRecvBandwidth;



    {:Define maximal bandwidth for all sending and receiving operations in bytes

     per second. If value is 0 (default), bandwidth limitation is not used.}

    property MaxBandwidth: Integer Write SetBandwidth;



    {:Do a conversion of non-standard line terminators to CRLF. (Off by default)

     If @True, then terminators like sigle CR, single LF or LFCR are converted

     to CRLF internally. This have effect only in @link(RecvString) method!}

    property ConvertLineEnd: Boolean read FConvertLineEnd Write FConvertLineEnd;



    {:Specified Family of this socket. When you are using Windows preliminary

     support for IPv6, then I recommend to set this property!}

    property Family: TSocketFamily read FFamily Write SetFamily;



    {:When resolving of domain name return both IPv4 and IPv6 addresses, then

     specify if is used IPv4 (dafault - @true) or IPv6.}

    property PreferIP4: Boolean read FPreferIP4 Write FPreferIP4;



    {:By default (@true) is all timeouts used as timeout between two packets in

     reading operations. If you set this to @false, then Timeouts is for overall

     reading operation!}

    property InterPacketTimeout: Boolean read FInterPacketTimeout Write FInterPacketTimeout;



    {:All sended datas was splitted by this value.}

    property SendMaxChunk: Integer read FSendMaxChunk Write FSendMaxChunk;



    {:By setting this property to @true you can stop any communication. You can

     use this property for soft abort of communication.}

    property StopFlag: Boolean read FStopFlag Write FStopFlag;



    {:Timeout for data sending by non-blocking socket mode.}

    property NonblockSendTimeout: Integer read FNonblockSendTimeout Write FNonblockSendTimeout;



    {:Timeout for @link(Connect) call. Default value 0 means default system timeout.

     Non-zero value means timeout in millisecond.}

    property ConnectionTimeout: Integer read FConnectionTimeout write FConnectionTimeout;



    {:This event is called by various reasons. It is good for monitoring socket,

     create gauges for data transfers, etc.}

    property OnStatus: THookSocketStatus read FOnStatus write FOnStatus;



    {:this event is good for some internal thinks about filtering readed datas.

     It is used by telnet client by example.}

    property OnReadFilter: THookDataFilter read FOnReadFilter write FOnReadFilter;



    {:This event is called after real socket creation for setting special socket

     options, because you not know when socket is created. (it is depended on

     Ipv4, IPv6 or automatic mode)}

    property OnCreateSocket: THookCreateSocket read FOnCreateSocket write FOnCreateSocket;



    {:This event is good for monitoring content of readed or writed datas.}

    property OnMonitor: THookMonitor read FOnMonitor write FOnMonitor;



    {:This event is good for calling your code during long socket operations.

      (Example, for refresing UI if class in not called within the thread.)

      Rate of heartbeats can be modified by @link(HeartbeatRate) property.}

    property OnHeartbeat: THookHeartbeat read FOnHeartbeat write FOnHeartbeat;



    {:Specify typical rate of @link(OnHeartbeat) event and @link(StopFlag) testing.

      Default value 0 disabling heartbeats! Value is in milliseconds.

      Real rate can be higher or smaller then this value, because it depending

      on real socket operations too!

      Note: Each heartbeat slowing socket processing.}

    property HeartbeatRate: integer read FHeartbeatRate Write FHeartbeatRate;

    {:What class own this socket? Used by protocol implementation classes.}

    property Owner: TObject read FOwner Write FOwner;

  end;



  {:@abstract(Support for SOCKS4 and SOCKS5 proxy)

   Layer with definition all necessary properties and functions for

   implementation SOCKS proxy client. Do not use this class directly.}

  TSocksBlockSocket = class(TBlockSocket)

  protected

    FSocksIP: string;

    FSocksPort: string;

    FSocksTimeout: integer;

    FSocksUsername: string;

    FSocksPassword: string;

    FUsingSocks: Boolean;

    FSocksResolver: Boolean;

    FSocksLastError: integer;

    FSocksResponseIP: string;

    FSocksResponsePort: string;

    FSocksLocalIP: string;

    FSocksLocalPort: string;

    FSocksRemoteIP: string;

    FSocksRemotePort: string;

    FBypassFlag: Boolean;

    FSocksType: TSocksType;

    function SocksCode(IP, Port: string): Ansistring;

    function SocksDecode(Value: Ansistring): integer;

  public

    constructor Create;



    {:Open connection to SOCKS proxy and if @link(SocksUsername) is set, do

     authorisation to proxy. This is needed only in special cases! (it is called

     internally!)}

    function SocksOpen: Boolean;



    {:Send specified request to SOCKS proxy. This is needed only in special

     cases! (it is called internally!)}

    function SocksRequest(Cmd: Byte; const IP, Port: string): Boolean;



    {:Receive response to previosly sended request. This is needed only in

     special cases! (it is called internally!)}

    function SocksResponse: Boolean;



    {:Is @True when class is using SOCKS proxy.}

    property UsingSocks: Boolean read FUsingSocks;



    {:If SOCKS proxy failed, here is error code returned from SOCKS proxy.}

    property SocksLastError: integer read FSocksLastError;

  published

    {:Address of SOCKS server. If value is empty string, SOCKS support is

     disabled. Assingning any value to this property enable SOCKS mode.

     Warning: You cannot combine this mode with HTTP-tunneling mode!}

    property SocksIP: string read FSocksIP write FSocksIP;



    {:Port of SOCKS server. Default value is '1080'.}

    property SocksPort: string read FSocksPort write FSocksPort;



    {:If you need authorisation on SOCKS server, set username here.}

    property SocksUsername: string read FSocksUsername write FSocksUsername;



    {:If you need authorisation on SOCKS server, set password here.}

    property SocksPassword: string read FSocksPassword write FSocksPassword;



    {:Specify timeout for communicatin with SOCKS server. Default is one minute.}

    property SocksTimeout: integer read FSocksTimeout write FSocksTimeout;



    {:If @True, all symbolic names of target hosts is not translated to IP's

     locally, but resolving is by SOCKS proxy. Default is @True.}

    property SocksResolver: Boolean read FSocksResolver write FSocksResolver;



    {:Specify SOCKS type. By default is used SOCKS5, but you can use SOCKS4 too.

     When you select SOCKS4, then if @link(SOCKSResolver) is enabled, then is

     used SOCKS4a. Othervise is used pure SOCKS4.}

    property SocksType: TSocksType read FSocksType write FSocksType;

  end;



  {:@abstract(Implementation of TCP socket.)

   Supported features: IPv4, IPv6, SSL/TLS or SSH (depending on used plugin),

   SOCKS5 proxy (outgoing connections and limited incomming), SOCKS4/4a proxy

   (outgoing connections and limited incomming), TCP through HTTP proxy tunnel.}

  TTCPBlockSocket = class(TSocksBlockSocket)

  protected

    FOnAfterConnect: THookAfterConnect;

    FSSL: TCustomSSL;

    FHTTPTunnelIP: string;

    FHTTPTunnelPort: string;

    FHTTPTunnel: Boolean;

    FHTTPTunnelRemoteIP: string;

    FHTTPTunnelRemotePort: string;

    FHTTPTunnelUser: string;

    FHTTPTunnelPass: string;

    FHTTPTunnelTimeout: integer;

    procedure SocksDoConnect(IP, Port: string);

    procedure HTTPTunnelDoConnect(IP, Port: string);

    procedure DoAfterConnect;

  public

    {:Create TCP socket class with default plugin for SSL/TSL/SSH implementation

    (see @link(SSLImplementation))}

    constructor Create;



    {:Create TCP socket class with desired plugin for SSL/TSL/SSH implementation}

    constructor CreateWithSSL(SSLPlugin: TSSLClass);

    destructor Destroy; override;



    {:See @link(TBlockSocket.CloseSocket)}

    procedure CloseSocket; override;



    {:See @link(TBlockSocket.WaitingData)}

    function WaitingData: Integer; override;



    {:Sets socket to receive mode for new incoming connections. It is necessary

     to use @link(TBlockSocket.BIND) function call before this method to select

     receiving port!



     If you use SOCKS, activate incoming TCP connection by this proxy. (By BIND

     method of SOCKS.)}

    procedure Listen; override;



    {:Waits until new incoming connection comes. After it comes a new socket is

     automatically created (socket handler is returned by this function as

     result).



     If you use SOCKS, new socket is not created! In this case is used same

     socket as socket for listening! So, you can accept only one connection in

     SOCKS mode.}

    function Accept: TSocket; override;



    {:Connects socket to remote IP address and PORT. The same rules as with

     @link(TBlockSocket.BIND) method are valid. The only exception is that PORT

     with 0 value will not be connected. After call to this method

     a communication channel between local and remote socket is created. Local

     socket is assigned automatically if not controlled by previous call to

     @link(TBlockSocket.BIND) method. Structures @link(TBlockSocket.LocalSin)

     and @link(TBlockSocket.RemoteSin) will be filled with valid values.



     If you use SOCKS, activate outgoing TCP connection by SOCKS proxy specified

     in @link(TSocksBlockSocket.SocksIP). (By CONNECT method of SOCKS.)



     If you use HTTP-tunnel mode, activate outgoing TCP connection by HTTP

     tunnel specified in @link(HTTPTunnelIP). (By CONNECT method of HTTP

     protocol.)



     Note: If you call this on non-created socket, then socket is created

     automaticly.}

    procedure Connect(IP, Port: string); override;



    {:If you need upgrade existing TCP connection to SSL/TLS (or SSH2, if plugin

     allows it) mode, then call this method. This method switch this class to

     SSL mode and do SSL/TSL handshake.}

    procedure SSLDoConnect;



    {:By this method you can downgrade existing SSL/TLS connection to normal TCP

     connection.}

    procedure SSLDoShutdown;



    {:If you need use this component as SSL/TLS TCP server, then after accepting

     of inbound connection you need start SSL/TLS session by this method. Before

     call this function, you must have assigned all neeeded certificates and

     keys!}

    function SSLAcceptConnection: Boolean;



    {:See @link(TBlockSocket.GetLocalSinIP)}

    function GetLocalSinIP: string; override;



    {:See @link(TBlockSocket.GetRemoteSinIP)}

    function GetRemoteSinIP: string; override;



    {:See @link(TBlockSocket.GetLocalSinPort)}

    function GetLocalSinPort: Integer; override;



    {:See @link(TBlockSocket.GetRemoteSinPort)}

    function GetRemoteSinPort: Integer; override;



    {:See @link(TBlockSocket.SendBuffer)}

    function SendBuffer(Buffer: TMemory; Length: Integer): Integer; override;



    {:See @link(TBlockSocket.RecvBuffer)}

    function RecvBuffer(Buffer: TMemory; Len: Integer): Integer; override;



    {:Return value of socket type. For TCP return SOCK_STREAM.}

    function GetSocketType: integer; override;



    {:Return value of protocol type for socket creation. For TCP return

     IPPROTO_TCP.}

    function GetSocketProtocol: integer; override;



    {:Class implementing SSL/TLS support. It is allways some descendant

     of @link(TCustomSSL) class. When programmer not select some SSL plugin

     class, then is used @link(TSSLNone)}

    property SSL: TCustomSSL read FSSL;



    {:@True if is used HTTP tunnel mode.}

    property HTTPTunnel: Boolean read FHTTPTunnel;

  published

    {:Return descriptive string for @link(LastError). On case of error

     in SSL/TLS subsystem, it returns right error description.}

    function GetErrorDescEx: string; override;



    {:Specify IP address of HTTP proxy. Assingning non-empty value to this

     property enable HTTP-tunnel mode. This mode is for tunnelling any outgoing

     TCP connection through HTTP proxy server. (If policy on HTTP proxy server

     allow this!) Warning: You cannot combine this mode with SOCK5 mode!}

    property HTTPTunnelIP: string read FHTTPTunnelIP Write FHTTPTunnelIP;



    {:Specify port of HTTP proxy for HTTP-tunneling.}

    property HTTPTunnelPort: string read FHTTPTunnelPort Write FHTTPTunnelPort;



    {:Specify authorisation username for access to HTTP proxy in HTTP-tunnel

     mode. If you not need authorisation, then let this property empty.}

    property HTTPTunnelUser: string read FHTTPTunnelUser Write FHTTPTunnelUser;



    {:Specify authorisation password for access to HTTP proxy in HTTP-tunnel

     mode.}

    property HTTPTunnelPass: string read FHTTPTunnelPass Write FHTTPTunnelPass;



    {:Specify timeout for communication with HTTP proxy in HTTPtunnel mode.}

    property HTTPTunnelTimeout: integer read FHTTPTunnelTimeout Write FHTTPTunnelTimeout;



    {:This event is called after sucessful TCP socket connection.}

    property OnAfterConnect: THookAfterConnect read FOnAfterConnect write FOnAfterConnect;

  end;



  {:@abstract(Datagram based communication)

   This class implementing datagram based communication instead default stream

   based communication style.}

  TDgramBlockSocket = class(TSocksBlockSocket)

  public

    {:Fill @link(TBlockSocket.RemoteSin) structure. This address is used for

     sending data.}

    procedure Connect(IP, Port: string); override;



    {:Silently redirected to @link(TBlockSocket.SendBufferTo).}

    function SendBuffer(Buffer: TMemory; Length: Integer): Integer; override;



    {:Silently redirected to @link(TBlockSocket.RecvBufferFrom).}

    function RecvBuffer(Buffer: TMemory; Length: Integer): Integer; override;

  end;



  {:@abstract(Implementation of UDP socket.)

   NOTE: in this class is all receiving redirected to RecvBufferFrom. You can

   use for reading any receive function. Preffered is RecvPacket! Similary all

   sending is redirected to SendbufferTo. You can use for sending UDP packet any

   sending function, like SendString.



   Supported features: IPv4, IPv6, unicasts, broadcasts, multicasts, SOCKS5

   proxy (only unicasts! Outgoing and incomming.)}

  TUDPBlockSocket = class(TDgramBlockSocket)

  protected

    FSocksControlSock: TTCPBlockSocket;

    function UdpAssociation: Boolean;

    procedure SetMulticastTTL(TT…