unit Unit1;

interface

uses
 Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
 Dialogs, StdCtrls;

type
 TForm1 = class(TForm)
   Button1: TButton;
   Memo1: TMemo;
   procedure Button1Click(Sender: TObject);
 private
   { Private declarations }
 public
   { Public declarations }
 end;

type
///////////////
// Некоторые объявления типов для Winsock 2
 u_char = Char;
 u_short = Word;
 u_int = Integer;
 u_long = Longint;

 SunB = packed record
   s_b1, s_b2, s_b3, s_b4: u_char;
 end;
 SunW = packed record
   s_w1, s_w2: u_short;
 end;
 in_addr = record
   case integer of
     0: (S_un_b: SunB);
     1: (S_un_w: SunW);
     2: (S_addr: u_long);
 end;
 TInAddr = in_addr;

 Sockaddr_in = record
   case Integer of
     0: (sin_family: u_short;
       sin_port: u_short;
       sin_addr: TInAddr;
       sin_zero: array[0..7] of Char);
     1: (sa_family: u_short;
       sa_data: array[0..13] of Char)
 end;
 TSockAddr = Sockaddr_in;
 TSocket = u_int;

const
 WSADESCRIPTION_LEN = 256;
 WSASYS_STATUS_LEN = 128;

type
 PWSAData = ^TWSAData;
 WSAData = record // !!! also WSDATA
   wVersion: Word;
   wHighVersion: Word;
   szDescription: array[0..WSADESCRIPTION_LEN] of Char;
   szSystemStatus: array[0..WSASYS_STATUS_LEN] of Char;
   iMaxSockets: Word;
   iMaxUdpDg: Word;
   lpVendorInfo: PChar;
 end;
 TWSAData = WSAData;

// Определяем необходимые функции winsock 2
function closesocket(s: TSocket): Integer; stdcall;
function socket(af, Struct, protocol: Integer): TSocket; stdcall;
function sendto(s: TSocket; var Buf; len, flags: Integer; var addrto: TSockAddr;
 tolen: Integer): Integer; stdcall; {}
function setsockopt(s: TSocket; level, optname: Integer; optval: PChar;
 optlen: Integer): Integer; stdcall;
function inet_addr(cp: PChar): u_long; stdcall; {PInAddr;} { TInAddr }
function htons(hostshort: u_short): u_short; stdcall;
function WSAGetLastError: Integer; stdcall;
function WSAStartup(wVersionRequired: word; var WSData: TWSAData): Integer; stdcall;
function WSACleanup: Integer; stdcall;

const
 AF_INET = 2; // internetwork: UDP, TCP, etc.

 IP_HDRINCL = 2; // включаем заголовок IP пакета

 SOCK_RAW = 3; // интерфейс raw-протокола

 IPPROTO_IP = 0; // dummy for IP
 IPPROTO_TCP = 6; // tcp
 IPPROTO_UDP = 17; // user datagram protocol
 IPPROTO_RAW = 255; // raw IP пакет

 INVALID_SOCKET = TSocket(not (0));
 SOCKET_ERROR = -1;

 SOCK_DGRAM = 2; // интерфейс udp-протокола
 IP_MULTICAST_LOOP = 4; //???
 IP_MULTICAST_IF = 2; //???
//http://www.blitzbasic.com/codearcs/codearcs.php?code=1270
////////////////

var
 Form1: TForm1;

implementation

// Импортируем функции Winsock 2
const WinSocket = 'WS2_32.DLL';

function closesocket; external winsocket name 'closesocket';
function socket; external winsocket name 'socket';
function sendto; external winsocket name 'sendto';
function setsockopt; external winsocket name 'setsockopt';
function inet_addr; external winsocket name 'inet_addr';
function htons; external winsocket name 'htons';
function WSAGetLastError; external winsocket name 'WSAGetLastError';
function WSAStartup; external winsocket name 'WSAStartup';
function WSACleanup; external winsocket name 'WSACleanup';

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
var
 wsdata: TWSAdata;
 ret: Integer;
 sd: TSocket;
 loopch: byte;
 groupSock: TSockAddr;
 localInterface: TInAddr;
 datalen: integer;
 databuf: array[0..1024] of byte;

begin
// Startup Winsock 2
 ret := WSAStartup($0002, wsdata);
 if ret <> 0 then begin
   memo1.lines.add('WSA Startup failed.');
   exit;
 end;
 with memo1.lines do begin
   add('WSA Startup:');
   add('Desc.: ' + wsData.szDescription);
   add('Status: ' + wsData.szSystemStatus);
 end;

 try

// Создаём сокет
   //sd := Socket(AF_INET, SOCK_RAW, IPPROTO_UDP);
   sd := socket(AF_INET, SOCK_DGRAM, 0);
   if (sd = INVALID_SOCKET) then begin
     memo1.lines.add('Socket() failed: ' + IntToStr(WSAGetLastError));
     exit;
   end;
   Memo1.lines.add('Socket Handle = ' + IntToStr(sd));

 (*
  * Initialize the group sockaddr structure with a
  * group address of 225.1.1.1 and port 5555.
  *)
// memset((char *) &groupSock, 0, sizeof(groupSock));  ???
   groupSock.sin_family := AF_INET;
   groupSock.sin_addr.s_addr := inet_addr('225.1.1.1');
   groupSock.sin_port := htons(5555);

 (*
  * Disable loopback so you do not receive your own datagrams.
  *)

   loopch := 0;
   ret := setsockopt(sd, IPPROTO_IP, IP_MULTICAST_LOOP, @loopch, sizeof(loopch));

   if ret = SOCKET_ERROR then begin
     Memo1.lines.add('setsockopt(IP_MULTICAST_LOOP) failed: ' + IntToStr(WSAGetLastError));
     exit;
   end;

  (*
   * set local interface for outbound multicast datagrams.
   * The IP address specified must be associated with a local,
   * multicast - capable interface.
   *)
   localInterface.s_addr := inet_addr('192.168.1.5');
   ret := setsockopt(sd, IPPROTO_IP, IP_MULTICAST_IF, @localInterface, sizeof(localInterface));

   if ret = SOCKET_ERROR then begin
     Memo1.lines.add('setsockopt(IP_MULTICAST_IF) failed: ' + IntToStr(WSAGetLastError));
     exit;
   end;

 (*
  * Send a message to the multicast group specified by the
  * groupSock sockaddr structure.
  *)
   datalen := 10;
   ret := sendto(sd, databuf, datalen, 0, groupSock, sizeof(groupSock));
   if ret = SOCKET_ERROR then begin
     Memo1.lines.add('sending datagram message: ' + IntToStr(WSAGetLastError));
     exit;
   end;

// Закрываем сокет
   CloseSocket(sd);
 finally
// Закрываем Winsock 2
   WSACleanup;
 end;

end;

end.

 ip_mreq = record
   imr_multiaddr: TInAddr; //* IP multicast address of group */
   imr_interface: TInAddr; //* local IP address of interface */
 end;
 Tip_mreq = ip_mreq;

procedure TForm1.Button4Click(Sender: TObject);
begin
 igmp_init_server('192.168.1.5');
 send_databuf[0] := 11; send_databuf[5] := 33; send_databuf[7] := 55; // test data
 igmp_send_data('225.1.1.1', 5555, 10);
end;

procedure TForm1.Button5Click(Sender: TObject);

var
 datalen, i: integer;

begin
 igmp_init_client('192.168.1.5', '225.1.1.1', 5555);
 igmp_recv_data(datalen);
 Memo1.lines.add('Bytes received: ' + inttostr(datalen));
 if datalen > 0 then for i := 0 to datalen - 1 do Memo1.lines.add(inttostr(i) + ' - ' + inttostr(recv_databuf[i]));
end;