# Copyright (c) 2014 Rackspace Hosting # All Rights Reserved. # # Licensed under the Apache License, Version 2.0 (the "License"); you may # not use this file except in compliance with the License. You may obtain # a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, WITHOUT # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the # License for the specific language governing permissions and limitations # under the License. import time import eventlet import dns import dns.rdataclass import dns.rdatatype import dns.exception import dns.flags import dns.rcode import dns.message import dns.opcode from oslo_config import cfg from oslo_log import log as logging from designate.mdns import base from designate.i18n import _LI from designate.i18n import _LW dns_query = eventlet.import_patched('dns.query') LOG = logging.getLogger(__name__) CONF = cfg.CONF class NotifyEndpoint(base.BaseEndpoint): RPC_API_VERSION = '2.0' RPC_API_NAMESPACE = 'notify' def notify_zone_changed(self, context, zone, host, port, timeout, retry_interval, max_retries, delay): """ :param context: The user context. :param zone: The designate zone object. This contains the zone name. :param host: A notify is sent to this host. :param port: A notify is sent to this port. :param timeout: The time (in seconds) to wait for a NOTIFY response from server. :param retry_interval: The time (in seconds) between retries. :param max_retries: The maximum number of retries mindns would do for sending a NOTIFY message. After this many retries, mindns gives up. :param delay: The time to wait before sending the first NOTIFY request. :return: a tuple of (response, current_retry) where response is the response on success or None on failure. current_retry is the current retry number. The return value is just used for testing and not by pool manager. """ time.sleep(delay) return self._make_and_send_dns_message( zone, host, port, timeout, retry_interval, max_retries, notify=True) def poll_for_serial_number(self, context, zone, nameserver, timeout, retry_interval, max_retries, delay): """Get the serial number of a zone on a resolver, then call update_status on Pool Manager to update the zone status. :param context: The user context. :param zone: The designate zone object. This contains the zone name. zone.serial = expected_serial :param nameserver: Destination for the poll :param timeout: The time (in seconds) to wait for a SOA response from nameserver. :param retry_interval: The time (in seconds) between retries. :param max_retries: The maximum number of retries mindns would do for an expected serial number. After this many retries, mindns returns an ERROR. :param delay: The time to wait before sending the first request. :return: None """ (status, actual_serial, retries) = self.get_serial_number( context, zone, nameserver.host, nameserver.port, timeout, retry_interval, max_retries, delay) self.pool_manager_api.update_status( context, zone, nameserver, status, actual_serial) def get_serial_number(self, context, zone, host, port, timeout, retry_interval, max_retries, delay): """ :param context: The user context. :param zone: The designate zone object. This contains the zone name. zone.serial = expected_serial :param host: A notify is sent to this host. :param port: A notify is sent to this port. :param timeout: The time (in seconds) to wait for a SOA response from nameserver. :param retry_interval: The time (in seconds) between retries. :param max_retries: The maximum number of retries mindns would do for an expected serial number. After this many retries, mindns returns an ERROR. :param delay: The time to wait before sending the first request. :return: a tuple of (status, actual_serial, retries) status is either "SUCCESS" or "ERROR". actual_serial is either the serial number returned in the SOA message from the nameserver or None. retries is the number of retries left. The return value is just used for testing and not by pool manager. The pool manager is informed of the status with update_status. """ actual_serial = None status = 'ERROR' retries = max_retries time.sleep(delay) while (True): (response, retry) = self._make_and_send_dns_message( zone, host, port, timeout, retry_interval, retries) if response and (response.rcode() in ( dns.rcode.NXDOMAIN, dns.rcode.REFUSED, dns.rcode.SERVFAIL) or not bool(response.answer)): status = 'NO_ZONE' if zone.serial == 0 and zone.action in ['DELETE', 'NONE']: return (status, 0, retries) elif response and len(response.answer) == 1 \ and str(response.answer[0].name) == str(zone.name) \ and response.answer[0].rdclass == dns.rdataclass.IN \ and response.answer[0].rdtype == dns.rdatatype.SOA: # parse the SOA response and get the serial number rrset = response.answer[0] actual_serial = rrset.to_rdataset().items[0].serial if actual_serial is None or actual_serial < zone.serial: # TODO(vinod): Account for serial number wrap around. retries = retries - retry LOG.warning(_LW("Got lower serial for '%(zone)s' to '%(host)s:" "%(port)s'. Expected:'%(es)d'. Got:'%(as)s'." "Retries left='%(retries)d'") % {'zone': zone.name, 'host': host, 'port': port, 'es': zone.serial, 'as': actual_serial, 'retries': retries}) if retries > 0: # retry again time.sleep(retry_interval) continue else: break else: # Everything looks good at this point. Return SUCCESS. status = 'SUCCESS' break # Return retries for testing purposes. return (status, actual_serial, retries) def _make_and_send_dns_message(self, zone, host, port, timeout, retry_interval, max_retries, notify=False): """ :param zone: The designate zone object. This contains the zone name. :param host: The destination host for the dns message. :param port: The destination port for the dns message. :param timeout: The time (in seconds) to wait for a response from destination. :param retry_interval: The time (in seconds) between retries. :param max_retries: The maximum number of retries mindns would do for a response. After this many retries, the function returns. :param notify: If true, a notify message is constructed else a SOA message is constructed. :return: a tuple of (response, current_retry) where response is the response on success or None on failure. current_retry is the current retry number """ dns_message = self._make_dns_message(zone.name, notify=notify) retry = 0 response = None while retry < max_retries: retry = retry + 1 LOG.info(_LI("Sending '%(msg)s' for '%(zone)s' to '%(server)s:" "%(port)d'."), {'msg': 'NOTIFY' if notify else 'SOA', 'zone': zone.name, 'server': host, 'port': port}) response = self._send_dns_message( dns_message, host, port, timeout) if isinstance(response, dns.exception.Timeout): LOG.warning( _LW("Got Timeout while trying to send '%(msg)s' for " "'%(zone)s' to '%(server)s:%(port)d'. Timeout=" "'%(timeout)d' seconds. Retry='%(retry)d'") % {'msg': 'NOTIFY' if notify else 'SOA', 'zone': zone.name, 'server': host, 'port': port, 'timeout': timeout, 'retry': retry}) response = None # retry sending the message if we get a Timeout. time.sleep(retry_interval) continue elif isinstance(response, dns_query.BadResponse): LOG.warning( _LW("Got BadResponse while trying to send '%(msg)s' " "for '%(zone)s' to '%(server)s:%(port)d'. Timeout" "='%(timeout)d' seconds. Retry='%(retry)d'") % {'msg': 'NOTIFY' if notify else 'SOA', 'zone': zone.name, 'server': host, 'port': port, 'timeout': timeout, 'retry': retry}) response = None break # Check that we actually got a NOERROR in the rcode and and an # authoritative answer elif (response.rcode() in (dns.rcode.NXDOMAIN, dns.rcode.REFUSED, dns.rcode.SERVFAIL)) or \ (response.rcode() == dns.rcode.NOERROR and not bool(response.answer)): LOG.info(_LI("%(zone)s not found on %(server)s:%(port)d"), {'zone': zone.name, 'server': host, 'port': port}) break elif not (response.flags & dns.flags.AA) or dns.rcode.from_flags( response.flags, response.ednsflags) != dns.rcode.NOERROR: LOG.warning( _LW("Failed to get expected response while trying to " "send '%(msg)s' for '%(zone)s' to '%(server)s:" "%(port)d'.\nResponse message:\n%(resp)s\n") % {'msg': 'NOTIFY' if notify else 'SOA', 'zone': zone.name, 'server': host, 'port': port, 'resp': str(response)}) response = None break else: break return (response, retry) 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 _send_dns_message(self, dns_message, host, port, timeout): """ :param dns_message: The dns message that needs to be sent. :param host: The destination ip of dns_message. :param port: The destination port of dns_message. :param timeout: The timeout in seconds to wait for a response. :return: response or dns.exception.Timeout or dns_query.BadResponse """ try: if not CONF['service:mdns'].all_tcp: response = dns_query.udp( dns_message, host, port=port, timeout=timeout) else: response = dns_query.tcp( dns_message, host, port=port, timeout=timeout) return response except dns.exception.Timeout as timeout: return timeout except dns_query.BadResponse as badResponse: return badResponse