Validate and parse DNS record data for a CAA record
    :param rdata: DNS record data
    :return: dict w/fields

def caa_rec(rdatas):
    '''
    Validate and parse DNS record data for a CAA record
    :param rdata: DNS record data
    :return: dict w/fields
    '''
    rschema = OrderedDict((
        ('flags', lambda flag: ['critical'] if int(flag) > 0 else []),
        ('tag', RFC.CAA_TAGS),
        ('value', lambda val: val.strip('\',"'))
    ))

    res = _data2rec_group(rschema, rdatas, 'tag')

    for tag in ('issue', 'issuewild'):
        tag_res = res.get(tag, False)
        if not tag_res:
            continue
        for idx, val in enumerate(tag_res):
            if ';' not in val:
                continue
            val, params = val.split(';', 1)
            params = dict(param.split('=') for param in shlex.split(params))
            tag_res[idx] = {val: params}

    return res