'Send an ethernet frame.
Send an ethernet frame, formating the header.
Args:
dst_mac: \'byte string\'
src_mac: \'byte string\'
protocol: short in host byte order
payload: \'byte string\''

def send_to(self, dst_mac, src_mac, protocol, payload):

    if (self._socket is None):
        raise error.TestError('Raw    socket    not    open')
    try:
        packet = ethernet.pack(dst_mac, src_mac, protocol, payload)
    except Exception:
        raise error.TestError('Invalid    Packet')
    self.send(packet)
