def dstport_to_icmptc(dstport):
    """
    Destination port to ICMP type- and code - definition taken from
    https://www.erg.abdn.ac.uk/users/gorry/course/inet-pages/icmp-code.html
    https://www.iana.org/assignments/icmp-parameters/icmp-parameters.xhtml

    Args:
        dstport     `int` destination port number
    Return:
        `int` icmp type, `int` icmp code
    """
    return int(dstport / 256), dstport % 256