def ethernet(packet_data):
    (send_mac, recv_mac, protocol) = struct.unpack('!6s 6s H', packet_data[:14])
    return (read_mac_addr(send_mac), read_mac_addr(recv_mac), socket.htons(protocol), packet_data[:14])
def ethernet(packet_data):
    (send_mac, recv_mac, protocol) = struct.unpack('!6s 6s H', packet_data[:14])
    return (read_mac_addr(send_mac), read_mac_addr(recv_mac), socket.htons(protocol), packet_data[:14])