Validate and parse DNS record data for TLSA record(s)
    :param rdata: DNS record data
    :return: dict w/fields

def tlsa_rec(rdata):
    '''
    Validate and parse DNS record data for TLSA record(s)
    :param rdata: DNS record data
    :return: dict w/fields
    '''
    rschema = OrderedDict((
        ('usage', RFC.TLSA_USAGE),
        ('selector', RFC.TLSA_SELECT),
        ('matching', RFC.TLSA_MATCHING),
        ('pub', str)
    ))

    return _data2rec(rschema, rdata)