CrcGenerator *crcGenerator;
Parser *parser;
CFSocketRef cfSocket;
CFRunLoopSourceRef cfSource;
struct sockaddr_in addr;
struct sockaddr_in addrOut;
CFDataRef addrData;
CFDataRef addrDataOut;
CFDataRef Data;
CFDataRef DataOut;

const char *ip = "0.0.0.0";
const char *ipOut = "192.168.2.255";
const int port = 8234;
const int minimalFrameSize = 3;

-(void) initNetworkCommunication
{
    CFSocketContext socketContext = {0, (__bridge void *)(self), NULL, NULL, NULL};

    cfSocket = CFSocketCreate(kCFAllocatorDefault, AF_INET, SOCK_DGRAM, IPPROTO_UDP, kCFSocketAcceptCallBack | kCFSocketDataCallBack, (CFSocketCallBack)socketCallback, &socketContext);

    if ( cfSocket == NULL) {
        NSLog(@"CfSocketCreate failed");
    }else{
        if( cfSocket ) {
            NSLog(@"Socket created ");

            //configure listening address
            memset(&addr, 0, sizeof(addr));
            addr.sin_len = sizeof(addr);
            addr.sin_family = AF_INET;
            addr.sin_port = htons(port); //port
            inet_pton(AF_INET,ip, &addr.sin_addr); //ip adress
            addrData = CFDataCreate(NULL, (const UInt8*)&addr, sizeof(addr));

            //configure output address
            memset(&addrOut, 0, sizeof(addrOut));
            addrOut.sin_len = sizeof(addrOut);
            addrOut.sin_family = AF_INET;
            addrOut.sin_port = htons(port); //port
            inet_pton(AF_INET,ipOut, &addrOut.sin_addr); //ip adress
            addrDataOut = CFDataCreate(NULL, (const UInt8*)&addrOut, sizeof(addrOut));

            //enable broadcast on the socket
            int flag = 1;
            CFSocketNativeHandle socket_handle = (CFSocketNativeHandle)CFSocketGetNative(cfSocket);
            int result = setsockopt(socket_handle, SOL_SOCKET, SO_BROADCAST, &flag, sizeof(flag));
            if ( result < 0 ) {
                NSLog(@"broadcast enable failed");
            }

            //set address of the socket to listen to
            CFSocketSetAddress (cfSocket, addrData);

            //CRC generation object
            crcGenerator = [[CrcGenerator alloc] init];
            //parser object
            parser = [[Parser alloc] init];
            parser.delegate = self;
        }
    }

    cfSource = CFSocketCreateRunLoopSource(kCFAllocatorDefault, cfSocket, 0);
    CFRunLoopAddSource(CFRunLoopGetCurrent(), cfSource, kCFRunLoopDefaultMode);

    CFRelease(cfSource);
    CFRelease(cfSocket);
    //CFRunLoopRun();
}

static void socketCallback(CFSocketRef cfSocket, CFSocketCallBackType
                           type, CFDataRef address, const void *data, void *userInfo)
{
    //conversion of data from bytes to string
    NSData * inputData = (__bridge NSData*)data;
    NSUInteger capacity = inputData.length * 2;

    NSMutableString *sbuf = [NSMutableString stringWithCapacity:capacity];
    const unsigned char *buf = inputData.bytes;
    NSInteger i;
    for (i=0; i<inputData.length; ++i) {
        [sbuf appendFormat:@"%02X", (NSUInteger)buf[i]];
    }
    //log for checking received frame
    NSLog(sbuf);

    //CRC check
    if(capacity > minimalFrameSize*2){
        uint8_t* inputByteData = (uint8_t*)inputData.bytes;
        uint8_t inputByteArray[inputData.length];
        memcpy(inputByteArray, inputByteData, inputData.length);
        uint16_t compCrc = [crcGenerator generateCRC:inputByteArray withFrameLength:(uint8_t*)(inputData.length - 2) negate:true];
        uint8_t crc[2];
        memcpy(crc, &compCrc, 2);

        if(inputByteArray[inputData.length - 2 ] == crc[0] && inputByteArray[inputData.length - 1] == crc[1])
        {
            NSLog(@"OK n");
            //parse
            [parser setFrameDataToParse:inputData];
        }
    }
}