Python dns.rdatatype() Examples

def iterate_rdatas(self, rdtype=dns.rdatatype.ANY,
                       covers=dns.rdatatype.NONE):
        """Return a generator which yields (name, ttl, rdata) tuples for
        all rdatas in the zone which have the specified I{rdtype}
        and I{covers}.  If I{rdtype} is dns.rdatatype.ANY, the default,
        then all rdatas will be matched.

        @param rdtype: int or string
        @type rdtype: int or string
        @param covers: the covered type (defaults to None)
        @type covers: int or string
        """

        if isinstance(rdtype, string_types):
            rdtype = dns.rdatatype.from_text(rdtype)
        if isinstance(covers, string_types):
            covers = dns.rdatatype.from_text(covers)
        for (name, node) in self.iteritems():
            for rds in node:
                if rdtype == dns.rdatatype.ANY or \
                   (rds.rdtype == rdtype and rds.covers == covers):
                    for rdata in rds:
                        yield (name, rds.ttl, rdata) 

def _make_dns_message(self, zone_name, notify=False):
        """
        This constructs a SOA query or a dns NOTIFY message.
        :param zone_name: The zone name for which a SOA/NOTIFY needs to be
            sent.
        :param notify: If true, a notify message is constructed else a SOA
            message is constructed.
        :return: The constructed message.
        """
        dns_message = dns.message.make_query(zone_name, dns.rdatatype.SOA)
        dns_message.flags = 0
        if notify:
            dns_message.set_opcode(dns.opcode.NOTIFY)
            dns_message.flags |= dns.flags.AA
        else:
            # Setting the flags to RD causes BIND9 to respond with a NXDOMAIN.
            dns_message.set_opcode(dns.opcode.QUERY)
            dns_message.flags |= dns.flags.RD

        return dns_message 

def iterate_rdatas(self, rdtype=dns.rdatatype.ANY,
                       covers=dns.rdatatype.NONE):
        """Return a generator which yields (name, ttl, rdata) tuples for
        all rdatas in the zone which have the specified I{rdtype}
        and I{covers}.  If I{rdtype} is dns.rdatatype.ANY, the default,
        then all rdatas will be matched.

        @param rdtype: int or string
        @type rdtype: int or string
        @param covers: the covered type (defaults to None)
        @type covers: int or string
        """

        if isinstance(rdtype, string_types):
            rdtype = dns.rdatatype.from_text(rdtype)
        if isinstance(covers, string_types):
            covers = dns.rdatatype.from_text(covers)
        for (name, node) in self.iteritems():
            for rds in node:
                if rdtype == dns.rdatatype.ANY or \
                   (rds.rdtype == rdtype and rds.covers == covers):
                    for rdata in rds:
                        yield (name, rds.ttl, rdata) 

def test_limit_notify_middleware(self):
        self.CONF.set_override('notify_delay', 0.1, 'service:agent')

        # Initialize the middlware
        placeholder_app = None
        middleware = dnsutils.LimitNotifyMiddleware(placeholder_app)

        # Prepare a NOTIFY
        zone_name = 'example.com.'
        notify = dns.message.make_query(zone_name, dns.rdatatype.SOA)
        notify.flags = 0
        notify.set_opcode(dns.opcode.NOTIFY)
        notify.flags |= dns.flags.AA

        # Send the NOTIFY through the middleware
        # No problem, middleware should return None to pass it on
        self.assertIsNone(middleware.process_request(notify)) 

def test_limit_notify_middleware_no_acquire(self, mock_acquire):
        self.CONF.set_override('notify_delay', 0.1, 'service:agent')

        # Initialize the middlware
        placeholder_app = None
        middleware = dnsutils.LimitNotifyMiddleware(placeholder_app)

        # Prepare a NOTIFY
        zone_name = 'example.com.'
        notify = dns.message.make_query(zone_name, dns.rdatatype.SOA)
        notify.flags = 0
        notify.set_opcode(dns.opcode.NOTIFY)
        notify.flags |= dns.flags.AA

        # Make a response object to match the middleware's return
        response = dns.message.make_response(notify)
        # Provide an authoritative answer
        response.flags |= dns.flags.AA

        # Send the NOTIFY through the middleware
        # Lock can't be acquired, a NOTIFY is already being worked on
        # so just return what would have come back for a successful NOTIFY
        # This needs to be a one item tuple for the serialization middleware
        self.assertEqual(middleware.process_request(notify), (response,)) 

def test_get_serial_number_nxdomain_deleted_zone(self, mock_sleep):
        # The zone is not found and it's not was supposed be there
        response = RoObject(
            answer=[RoObject(
                rdclass=dns.rdataclass.IN,
                rdtype=dns.rdatatype.SOA
            )],
            rcode=mock.Mock(return_value=dns.rcode.NXDOMAIN)
        )
        zone = RoObject(name='zn', serial=0, action='DELETE')
        self.notify._make_and_send_dns_message = mock.Mock(
            return_value=(response, 1)
        )

        out = self.notify.get_serial_number(
            'c', zone, 'h', 1234, 1, 2, 3, 4
        )

        self.assertEqual(('NO_ZONE', 0, 3), out) 

def test_get_serial_number_ok(self, mock_sleep):
        zone = RoObject(name='zn', serial=314)
        ds = RoObject(items=[zone])
        response = RoObject(
            answer=[RoObject(
                name='zn',
                rdclass=dns.rdataclass.IN,
                rdtype=dns.rdatatype.SOA,
                to_rdataset=mock.Mock(return_value=ds)
            )],
            rcode=mock.Mock(return_value=dns.rcode.NOERROR)
        )
        self.notify._make_and_send_dns_message = mock.Mock(
            return_value=(response, 1)
        )

        out = self.notify.get_serial_number(
            'c', zone, 'h', 1234, 1, 2, 3, 4
        )

        self.assertEqual(('SUCCESS', 314, 3), out) 

def test_get_serial_number_too_many_retries(self, mock_sleep):
        zone = RoObject(name='zn', serial=314)
        ds = RoObject(items=[RoObject(serial=310)])
        response = RoObject(
            answer=[RoObject(
                name='zn',
                rdclass=dns.rdataclass.IN,
                rdtype=dns.rdatatype.SOA,
                to_rdataset=mock.Mock(return_value=ds)
            )],
            rcode=mock.Mock(return_value=dns.rcode.NOERROR)
        )
        self.notify._make_and_send_dns_message = mock.Mock(
            return_value=(response, 1)
        )

        out = self.notify.get_serial_number(
            'c', zone, 'h', 1234, 1, 2, 3, 4
        )

        self.assertEqual(('ERROR', 310, 0), out) 

def find_zone_serial(self, zone_name):
        LOG.debug("Finding %s", zone_name)

        zone_name = zone_name.rstrip('.')
        output = self.denominator.get_record(
            zone=zone_name,
            type='SOA',
            name=zone_name)
        try:
            text = ' '.join(output.split()[3:])
            rdata = dns.rdata.from_text(dns.rdataclass.IN,
                                        dns.rdatatype.SOA,
                                        text)
        except Exception:
            return None
        return rdata.serial 

def _build_resource_to_address_map(answer):
    """Return a dictionary that maps resource name to address.
    The response from any DNS query is a list of answer records and
    a list of additional records that may be useful.  In the case of
    SRV queries, the answer section contains SRV records which contain
    the service weighting information and a DNS resource name which
    requires further resolution.  The additional records segment may
    contain A records for the resources.  This function collects them
    into a dictionary that maps resource name to an array of addresses.
    :rtype: dict
    """
    mapping = collections.defaultdict(list)
    for resource in answer.response.additional:
        target = resource.name.to_text()
        mapping[target].extend(record.address
                               for record in resource.items
                               if record.rdtype == dns.rdatatype.A)
    return mapping 

def iterate_rdatas(self, rdtype=dns.rdatatype.ANY,
                       covers=dns.rdatatype.NONE):
        """Return a generator which yields (name, ttl, rdata) tuples for
        all rdatas in the zone which have the specified I{rdtype}
        and I{covers}.  If I{rdtype} is dns.rdatatype.ANY, the default,
        then all rdatas will be matched.

        @param rdtype: int or string
        @type rdtype: int or string
        @param covers: the covered type (defaults to None)
        @type covers: int or string
        """

        if isinstance(rdtype, (str, unicode)):
            rdtype = dns.rdatatype.from_text(rdtype)
        if isinstance(covers, (str, unicode)):
            covers = dns.rdatatype.from_text(covers)
        for (name, node) in self.iteritems():
            for rds in node:
                if rdtype == dns.rdatatype.ANY or \
                   (rds.rdtype == rdtype and rds.covers == covers):
                    for rdata in rds:
                        yield (name, rds.ttl, rdata) 

def iterate_rdatas(self, rdtype=dns.rdatatype.ANY,
                       covers=dns.rdatatype.NONE):
        """Return a generator which yields (name, ttl, rdata) tuples for
        all rdatas in the zone which have the specified I{rdtype}
        and I{covers}.  If I{rdtype} is dns.rdatatype.ANY, the default,
        then all rdatas will be matched.

        @param rdtype: int or string
        @type rdtype: int or string
        @param covers: the covered type (defaults to None)
        @type covers: int or string
        """

        if isinstance(rdtype, string_types):
            rdtype = dns.rdatatype.from_text(rdtype)
        if isinstance(covers, string_types):
            covers = dns.rdatatype.from_text(covers)
        for (name, node) in self.iteritems():
            for rds in node:
                if rdtype == dns.rdatatype.ANY or \
                   (rds.rdtype == rdtype and rds.covers == covers):
                    for rdata in rds:
                        yield (name, rds.ttl, rdata) 

def iterate_rdatas(self, rdtype=dns.rdatatype.ANY,
                       covers=dns.rdatatype.NONE):
        """Return a generator which yields (name, ttl, rdata) tuples for
        all rdatas in the zone which have the specified I{rdtype}
        and I{covers}.  If I{rdtype} is dns.rdatatype.ANY, the default,
        then all rdatas will be matched.

        @param rdtype: int or string
        @type rdtype: int or string
        @param covers: the covered type (defaults to None)
        @type covers: int or string
        """

        if isinstance(rdtype, string_types):
            rdtype = dns.rdatatype.from_text(rdtype)
        if isinstance(covers, string_types):
            covers = dns.rdatatype.from_text(covers)
        for (name, node) in self.iteritems():
            for rds in node:
                if rdtype == dns.rdatatype.ANY or \
                   (rds.rdtype == rdtype and rds.covers == covers):
                    for rdata in rds:
                        yield (name, rds.ttl, rdata) 

def iterate_rdatas(self, rdtype=dns.rdatatype.ANY,
                       covers=dns.rdatatype.NONE):
        """Return a generator which yields (name, ttl, rdata) tuples for
        all rdatas in the zone which have the specified I{rdtype}
        and I{covers}.  If I{rdtype} is dns.rdatatype.ANY, the default,
        then all rdatas will be matched.

        @param rdtype: int or string
        @type rdtype: int or string
        @param covers: the covered type (defaults to None)
        @type covers: int or string
        """

        if isinstance(rdtype, string_types):
            rdtype = dns.rdatatype.from_text(rdtype)
        if isinstance(covers, string_types):
            covers = dns.rdatatype.from_text(covers)
        for (name, node) in self.iteritems():
            for rds in node:
                if rdtype == dns.rdatatype.ANY or \
                   (rds.rdtype == rdtype and rds.covers == covers):
                    for rdata in rds:
                        yield (name, rds.ttl, rdata) 

def find_rrset(self, name, rdtype, covers=dns.rdatatype.NONE):
        """Look for rdata with the specified name and type in the zone,
        and return an RRset encapsulating it.

        The I{name}, I{rdtype}, and I{covers} parameters may be
        strings, in which case they will be converted to their proper
        type.

        This method is less efficient than the similar
        L{find_rdataset} because it creates an RRset instead of
        returning the matching rdataset.  It may be more convenient
        for some uses since it returns an object which binds the owner
        name to the rdata.

        This method may not be used to create new nodes or rdatasets;
        use L{find_rdataset} instead.

        KeyError is raised if the name or type are not found.
        Use L{get_rrset} if you want to have None returned instead.

        @param name: the owner name to look for
        @type name: DNS.name.Name object or string
        @param rdtype: the rdata type desired
        @type rdtype: int or string
        @param covers: the covered type (defaults to None)
        @type covers: int or string
        @raises KeyError: the node or rdata could not be found
        @rtype: dns.rrset.RRset object
        """

        name = self._validate_name(name)
        if isinstance(rdtype, string_types):
            rdtype = dns.rdatatype.from_text(rdtype)
        if isinstance(covers, string_types):
            covers = dns.rdatatype.from_text(covers)
        rdataset = self.nodes[name].find_rdataset(self.rdclass, rdtype, covers)
        rrset = dns.rrset.RRset(name, self.rdclass, rdtype, covers)
        rrset.update(rdataset)
        return rrset 

def get_rrset(self, name, rdtype, covers=dns.rdatatype.NONE):
        """Look for rdata with the specified name and type in the zone,
        and return an RRset encapsulating it.

        The I{name}, I{rdtype}, and I{covers} parameters may be
        strings, in which case they will be converted to their proper
        type.

        This method is less efficient than the similar L{get_rdataset}
        because it creates an RRset instead of returning the matching
        rdataset.  It may be more convenient for some uses since it
        returns an object which binds the owner name to the rdata.

        This method may not be used to create new nodes or rdatasets;
        use L{find_rdataset} instead.

        None is returned if the name or type are not found.
        Use L{find_rrset} if you want to have KeyError raised instead.

        @param name: the owner name to look for
        @type name: DNS.name.Name object or string
        @param rdtype: the rdata type desired
        @type rdtype: int or string
        @param covers: the covered type (defaults to None)
        @type covers: int or string
        @rtype: dns.rrset.RRset object
        """

        try:
            rrset = self.find_rrset(name, rdtype, covers)
        except KeyError:
            rrset = None
        return rrset 

def get_rrset(self, name, rdtype, covers=dns.rdatatype.NONE):
        """Look for rdata with the specified name and type in the zone,
        and return an RRset encapsulating it.

        The I{name}, I{rdtype}, and I{covers} parameters may be
        strings, in which case they will be converted to their proper
        type.

        This method is less efficient than the similar L{get_rdataset}
        because it creates an RRset instead of returning the matching
        rdataset.  It may be more convenient for some uses since it
        returns an object which binds the owner name to the rdata.

        This method may not be used to create new nodes or rdatasets;
        use L{find_rdataset} instead.

        None is returned if the name or type are not found.
        Use L{find_rrset} if you want to have KeyError raised instead.

        @param name: the owner name to look for
        @type name: DNS.name.Name object or string
        @param rdtype: the rdata type desired
        @type rdtype: int or string
        @param covers: the covered type (defaults to None)
        @type covers: int or string
        @rtype: dns.rrset.RRset object
        """

        try:
            rrset = self.find_rrset(name, rdtype, covers)
        except KeyError:
            rrset = None
        return rrset 

def find_rdataset(self, name, rdtype, covers=dns.rdatatype.NONE,
                      create=False):
        """Look for rdata with the specified name and type in the zone,
        and return an rdataset encapsulating it.

        The I{name}, I{rdtype}, and I{covers} parameters may be
        strings, in which case they will be converted to their proper
        type.

        The rdataset returned is not a copy; changes to it will change
        the zone.

        KeyError is raised if the name or type are not found.
        Use L{get_rdataset} if you want to have None returned instead.

        @param name: the owner name to look for
        @type name: DNS.name.Name object or string
        @param rdtype: the rdata type desired
        @type rdtype: int or string
        @param covers: the covered type (defaults to None)
        @type covers: int or string
        @param create: should the node and rdataset be created if they do not
        exist?
        @type create: bool
        @raises KeyError: the node or rdata could not be found
        @rtype: dns.rrset.RRset object
        """

        name = self._validate_name(name)
        if isinstance(rdtype, string_types):
            rdtype = dns.rdatatype.from_text(rdtype)
        if isinstance(covers, string_types):
            covers = dns.rdatatype.from_text(covers)
        node = self.find_node(name, create)
        return node.find_rdataset(self.rdclass, rdtype, covers, create) 

def get_rdataset(self, name, rdtype, covers=dns.rdatatype.NONE,
                     create=False):
        """Look for rdata with the specified name and type in the zone,
        and return an rdataset encapsulating it.

        The I{name}, I{rdtype}, and I{covers} parameters may be
        strings, in which case they will be converted to their proper
        type.

        The rdataset returned is not a copy; changes to it will change
        the zone.

        None is returned if the name or type are not found.
        Use L{find_rdataset} if you want to have KeyError raised instead.

        @param name: the owner name to look for
        @type name: DNS.name.Name object or string
        @param rdtype: the rdata type desired
        @type rdtype: int or string
        @param covers: the covered type (defaults to None)
        @type covers: int or string
        @param create: should the node and rdataset be created if they do not
        exist?
        @type create: bool
        @rtype: dns.rrset.RRset object
        """

        try:
            rdataset = self.find_rdataset(name, rdtype, covers, create)
        except KeyError:
            rdataset = None
        return rdataset 

def delete_rdataset(self, name, rdtype, covers=dns.rdatatype.NONE):
        """Delete the rdataset matching I{rdtype} and I{covers}, if it
        exists at the node specified by I{name}.

        The I{name}, I{rdtype}, and I{covers} parameters may be
        strings, in which case they will be converted to their proper
        type.

        It is not an error if the node does not exist, or if there is no
        matching rdataset at the node.

        If the node has no rdatasets after the deletion, it will itself
        be deleted.

        @param name: the owner name to look for
        @type name: DNS.name.Name object or string
        @param rdtype: the rdata type desired
        @type rdtype: int or string
        @param covers: the covered type (defaults to None)
        @type covers: int or string
        """

        name = self._validate_name(name)
        if isinstance(rdtype, string_types):
            rdtype = dns.rdatatype.from_text(rdtype)
        if isinstance(covers, string_types):
            covers = dns.rdatatype.from_text(covers)
        node = self.get_node(name)
        if node is not None:
            node.delete_rdataset(self.rdclass, rdtype, covers)
            if len(node) == 0:
                self.delete_node(name) 

def check_origin(self):
        """Do some simple checking of the zone's origin.

        @raises dns.zone.NoSOA: there is no SOA RR
        @raises dns.zone.NoNS: there is no NS RRset
        @raises KeyError: there is no origin node
        """
        if self.relativize:
            name = dns.name.empty
        else:
            name = self.origin
        if self.get_rdataset(name, dns.rdatatype.SOA) is None:
            raise NoSOA
        if self.get_rdataset(name, dns.rdatatype.NS) is None:
            raise NoNS 

def delete_rdataset(self, name, rdtype, covers=dns.rdatatype.NONE):
        """Delete the rdataset matching I{rdtype} and I{covers}, if it
        exists at the node specified by I{name}.

        The I{name}, I{rdtype}, and I{covers} parameters may be
        strings, in which case they will be converted to their proper
        type.

        It is not an error if the node does not exist, or if there is no
        matching rdataset at the node.

        If the node has no rdatasets after the deletion, it will itself
        be deleted.

        @param name: the owner name to look for
        @type name: DNS.name.Name object or string
        @param rdtype: the rdata type desired
        @type rdtype: int or string
        @param covers: the covered type (defaults to None)
        @type covers: int or string
        """

        name = self._validate_name(name)
        if isinstance(rdtype, string_types):
            rdtype = dns.rdatatype.from_text(rdtype)
        if isinstance(covers, string_types):
            covers = dns.rdatatype.from_text(covers)
        node = self.get_node(name)
        if node is not None:
            node.delete_rdataset(self.rdclass, rdtype, covers)
            if len(node) == 0:
                self.delete_node(name) 

def find_rrset(self, name, rdtype, covers=dns.rdatatype.NONE):
        """Look for rdata with the specified name and type in the zone,
        and return an RRset encapsulating it.

        The I{name}, I{rdtype}, and I{covers} parameters may be
        strings, in which case they will be converted to their proper
        type.

        This method is less efficient than the similar
        L{find_rdataset} because it creates an RRset instead of
        returning the matching rdataset.  It may be more convenient
        for some uses since it returns an object which binds the owner
        name to the rdata.

        This method may not be used to create new nodes or rdatasets;
        use L{find_rdataset} instead.

        KeyError is raised if the name or type are not found.
        Use L{get_rrset} if you want to have None returned instead.

        @param name: the owner name to look for
        @type name: DNS.name.Name object or string
        @param rdtype: the rdata type desired
        @type rdtype: int or string
        @param covers: the covered type (defaults to None)
        @type covers: int or string
        @raises KeyError: the node or rdata could not be found
        @rtype: dns.rrset.RRset object
        """

        name = self._validate_name(name)
        if isinstance(rdtype, string_types):
            rdtype = dns.rdatatype.from_text(rdtype)
        if isinstance(covers, string_types):
            covers = dns.rdatatype.from_text(covers)
        rdataset = self.nodes[name].find_rdataset(self.rdclass, rdtype, covers)
        rrset = dns.rrset.RRset(name, self.rdclass, rdtype, covers)
        rrset.update(rdataset)
        return rrset 

def delete_rdataset(self, name, rdtype, covers=dns.rdatatype.NONE):
        """Delete the rdataset matching I{rdtype} and I{covers}, if it
        exists at the node specified by I{name}.

        The I{name}, I{rdtype}, and I{covers} parameters may be
        strings, in which case they will be converted to their proper
        type.

        It is not an error if the node does not exist, or if there is no
        matching rdataset at the node.

        If the node has no rdatasets after the deletion, it will itself
        be deleted.

        @param name: the owner name to look for
        @type name: DNS.name.Name object or string
        @param rdtype: the rdata type desired
        @type rdtype: int or string
        @param covers: the covered type (defaults to None)
        @type covers: int or string
        """

        name = self._validate_name(name)
        if isinstance(rdtype, string_types):
            rdtype = dns.rdatatype.from_text(rdtype)
        if isinstance(covers, string_types):
            covers = dns.rdatatype.from_text(covers)
        node = self.get_node(name)
        if node is not None:
            node.delete_rdataset(self.rdclass, rdtype, covers)
            if len(node) == 0:
                self.delete_node(name) 

def get_rdataset(self, name, rdtype, covers=dns.rdatatype.NONE,
                     create=False):
        """Look for rdata with the specified name and type in the zone,
        and return an rdataset encapsulating it.

        The I{name}, I{rdtype}, and I{covers} parameters may be
        strings, in which case they will be converted to their proper
        type.

        The rdataset returned is not a copy; changes to it will change
        the zone.

        None is returned if the name or type are not found.
        Use L{find_rdataset} if you want to have KeyError raised instead.

        @param name: the owner name to look for
        @type name: DNS.name.Name object or string
        @param rdtype: the rdata type desired
        @type rdtype: int or string
        @param covers: the covered type (defaults to None)
        @type covers: int or string
        @param create: should the node and rdataset be created if they do not
        exist?
        @type create: bool
        @rtype: dns.rrset.RRset object
        """

        try:
            rdataset = self.find_rdataset(name, rdtype, covers, create)
        except KeyError:
            rdataset = None
        return rdataset 

def find_rdataset(self, name, rdtype, covers=dns.rdatatype.NONE,
                      create=False):
        """Look for rdata with the specified name and type in the zone,
        and return an rdataset encapsulating it.

        The I{name}, I{rdtype}, and I{covers} parameters may be
        strings, in which case they will be converted to their proper
        type.

        The rdataset returned is not a copy; changes to it will change
        the zone.

        KeyError is raised if the name or type are not found.
        Use L{get_rdataset} if you want to have None returned instead.

        @param name: the owner name to look for
        @type name: DNS.name.Name object or string
        @param rdtype: the rdata type desired
        @type rdtype: int or string
        @param covers: the covered type (defaults to None)
        @type covers: int or string
        @param create: should the node and rdataset be created if they do not
        exist?
        @type create: bool
        @raises KeyError: the node or rdata could not be found
        @rtype: dns.rrset.RRset object
        """

        name = self._validate_name(name)
        if isinstance(rdtype, string_types):
            rdtype = dns.rdatatype.from_text(rdtype)
        if isinstance(covers, string_types):
            covers = dns.rdatatype.from_text(covers)
        node = self.find_node(name, create)
        return node.find_rdataset(self.rdclass, rdtype, covers, create) 

def ns(fqdn, dns_server=None):
    """Resolve DNS zone.
    """
    return [str(rec) for rec in query(fqdn, dns.rdatatype.NS, dns_server)] 

def soa(label, dns_server=None):
    """Resolve a SOA resource record

    :param label: label to lookup
    :type zone: str

    :param dns_server: dns host and port information
    :type dns_server: (list, int)

    :return: a list of soa records
    """
    return query(label, dns.rdatatype.SOA, dns_server) 

def srv(label, dns_server=None, ignore_additional=True):
    """Resolve a CNAME resource record

    :param label: label to lookup
    :type zone: str

    :param dns_server: dns host and port information
    :type dns_server: (list, int)

    :return: a list of tuples (ip, port, prio, weight)
    """
    return _build_result_set(query(label, dns.rdatatype.SRV, dns_server),
                             ignore_additional) 

def cname(label, dns_server=None):
    """Resolve a CNAME resource record

    :param label: label to lookup
    :type zone: str

    :param dns_server: dns host and port information
    :type dns_server: (list, int)

    :return: a list of cnames
    """
    return [str(rec) for rec in query(label, dns.rdatatype.CNAME, dns_server)]