id = os.getpid() & 0xFFFF
sequenceNum = 0

def sendPacket() :

    checksum = ((2048) + 0 + id + sequenceNum) & 0xFFFF
    checksum = calculateCheckSum(checksum)

    # Header is type (8), code (8), checksum (16), id (16), sequence (16)
    header = struct.pack("!BBHHH", 8, 0, checksum, id, sequenceNum)
    #payload = '0123456789012345678901234567890123456789012345678901234'
    sequenceNum++;

def calculateCheckSum(checksum) :

    return 0  & 0xFFFF;