DWORD g_last_time;
CRITICAL_SECTION timesec;
//////////////////////////////////////////////////////////////////////////
DWORD WINAPI TimeCheckThread(LPVOID lp)
{

	while(TRUE){
		EnterCriticalSection(&timesec);
		if(GetTickCount()-g_last_time > 200){ // signal lost more than 200ms
			printf("SIGNAL LOST\r");
		}else{
			printf("SIGNAL GOOD\r");
		}
		LeaveCriticalSection(&timesec);
		Sleep(1);
	}

	return 0;
}

//////////////////////////////////////////////////////////////////////////
void CaptureLoop(SOCKET ssock)
{
	char *pdata = (char*)malloc(65536);
	int isize = 0;
	DWORD tid;
	
	printf("waiting for broadcast signals...\n");

	InitializeCriticalSection(&timesec);

	g_last_time = GetTickCount();
	CreateThread(0,0,TimeCheckThread,0,0,&tid);

	while(!_kbhit()){

		isize = recvfrom(ssock, pdata, 65536, 0, 0, 0);

		if(isize > 0){
			// analyse the packet
			PACKET *ppack = (PPACKET)pdata;

			if(ppack->iphdr.ip_protocol == IPPROTO_UDP)
				if(ppack->udphdr.dst_port == htons(33333))
					if(memcmp((((LPBYTE)ppack)+sizeof(PACKET)), "BROADCAST_SIG", 13)==0){
						EnterCriticalSection(&timesec);
						g_last_time = GetTickCount();
						LeaveCriticalSection(&timesec);
					}
				
		}

	}

	free(pdata);
}

procedure TForm1.IdTCPServer1Execute(AThread: TIdPeerThread);
var TempStr:TStringList;
    Command:String;
begin
if not AThread.Terminated and AThread.Connection.Connected then begin
    
    TempStr:=TStringList.Create;
    Command:=AThread.Connection.ReadLn;
    try
    //memo1.Lines.Add(Command);
      try
      Section.Enter;
      Spisok.Add(Command);
      finally
      Section.Leave;
      end;
//==============================================================================
    TempStr.Clear;
    TempStr.Add(IntToStr(Length(Command)));
    AThread.Connection.WriteStrings(TempStr);
//==============================================================================
    Except
    AThread.Connection.Disconnect;
    end;
    TempStr.Free;
end;
end;