def tcp_mapping_request(local_conn, remote_ip, remote_port):        while True:        remote_conn = socket.socket(socket.AF_INET, socket.SOCK_STREAM)        try:            remote_conn.settimeout(3)            remote_conn.connect((remote_ip, remote_port))        except Exception:            logger.error('Unable to connect to the remote server.')            continue        threading.Thread(target=tcp_mapping_worker, args=(local_conn, remote_conn)).start()        threading.Thread(target=tcp_mapping_worker, args=(remote_conn, local_conn)).start()        return

def tcp_mapping_worker(conn_receiver, conn_sender):    while True:        try:            data = conn_receiver.recv(PKT_BUFF_SIZE)        except Exception:            logger.debug('Connection closed.')            break        if not data:            logger.info('No more data is received.')            break        try:            conn_sender.sendall(data)        except Exception:            logger.error('Failed sending data.')            break