def get_mtu(self):
    '''Use socket ioctl call to get MTU size'''
    s = socket.socket(type=socket.SOCK_DGRAM)
    ifr = self.ifname + '\x00'*(32-len(self.ifname))
    try:
        ifs = ioctl(s, SIOCGIFMTU, ifr)
        mtu = struct.unpack('<H',ifs[16:18])[0]
    except Exception, s:
        logger.critical('socket ioctl call failed: {0}'.format(s))
        raise

    logger.debug('get_mtu: mtu of {0} = {1}'.format(self.ifname, mtu))
    self.mtu = mtu
    return mtu

 def set_mtu(self, mtu):
    '''Use socket ioctl call to set MTU size'''
    s = socket.socket(type=socket.SOCK_DGRAM)
    ifr = struct.pack('<16sH', self.ifname, mtu) + '\x00'*14
    try:
        ifs = ioctl(s, SIOCSIFMTU, ifr)
        self.mtu = struct.unpack('<H',ifs[16:18])[0]
    except Exception, s:
        logger.critical('socket ioctl call failed: {0}'.format(s))
        raise

    logger.debug('set_mtu: mtu of {0} = {1}'.format(self.ifname, self.mtu))

    return self.mtu