525 lines
21 KiB
Python
525 lines
21 KiB
Python
#!/usr/bin/env python3
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# DNSAggregatorInstance.py - Class implementing a DNS aggregator and run by pvcd
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# Part of the Parallel Virtual Cluster (PVC) system
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#
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# Copyright (C) 2018 Joshua M. Boniface <joshua@boniface.me>
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <https://www.gnu.org/licenses/>.
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#
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###############################################################################
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import os
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import sys
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import time
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import threading
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import dns.zone
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import dns.query
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import psycopg2
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import pvcd.log as log
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import pvcd.zkhandler as zkhandler
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import pvcd.common as common
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class DNSAggregatorInstance(object):
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# Initialization function
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def __init__(self, zk_conn, config, logger):
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self.zk_conn = zk_conn
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self.config = config
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self.logger = logger
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self.dns_networks = dict()
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self.is_active = False
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self.dns_server_daemon = PowerDNSInstance(self)
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self.dns_axfr_daemon = AXFRDaemonInstance(self)
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# Start up the PowerDNS instance
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def start_aggregator(self):
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# Restart the SQL connection
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self.dns_server_daemon.start()
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self.dns_axfr_daemon.start()
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self.is_active = True
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# Stop the PowerDNS instance
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def stop_aggregator(self):
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self.is_active = False
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self.dns_axfr_daemon.stop()
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self.dns_server_daemon.stop()
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def add_network(self, network):
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self.dns_networks[network] = DNSNetworkInstance(self, network)
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self.dns_networks[network].add_network()
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self.dns_axfr_daemon.update_networks(self.dns_networks)
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def remove_network(self, network):
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if self.dns_networks[network]:
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self.dns_networks[network].remove_network()
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del self.dns_networks[network]
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self.dns_axfr_daemon.update_networks(self.dns_networks)
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class PowerDNSInstance(object):
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# Initialization function
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def __init__(self, aggregator):
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self.aggregator = aggregator
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self.config = self.aggregator.config
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self.logger = self.aggregator.logger
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self.dns_server_daemon = None
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# Floating upstreams
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self.vni_dev = self.config['vni_dev']
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self.vni_ipaddr, self.vni_cidrnetmask = self.config['vni_floating_ip'].split('/')
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self.upstream_dev = self.config['upstream_dev']
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self.upstream_ipaddr, self.upstream_cidrnetmask = self.config['upstream_floating_ip'].split('/')
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def start(self):
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self.logger.out(
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'Starting PowerDNS zone aggregator',
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state='i'
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)
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# Define the PowerDNS config
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dns_configuration = [
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# Option # Explanation
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'--no-config',
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'--daemon=no', # Start directly
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'--guardian=yes', # Use a guardian
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'--disable-syslog=yes', # Log only to stdout (which is then captured)
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'--disable-axfr=no', # Allow AXFRs
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'--allow-axfr-ips=0.0.0.0/0', # Allow AXFRs to anywhere
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'--local-address={},{}'.format(self.vni_ipaddr, self.upstream_ipaddr),
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# Listen on floating IPs
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'--local-port=53', # On port 53
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'--log-dns-details=on', # Log details
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'--loglevel=3', # Log info
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'--master=yes', # Enable master mode
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'--slave=yes', # Enable slave mode
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'--slave-renotify=yes', # Renotify out for our slaved zones
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'--version-string=powerdns', # Set the version string
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'--default-soa-name=dns.pvc.local', # Override dnsmasq's invalid name
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'--socket-dir={}'.format(self.config['pdns_dynamic_directory']),
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# Standard socket directory
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'--launch=gpgsql', # Use the PostgreSQL backend
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'--gpgsql-host={}'.format(self.config['pdns_postgresql_host']),
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# PostgreSQL instance
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'--gpgsql-port={}'.format(self.config['pdns_postgresql_port']),
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# Default port
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'--gpgsql-dbname={}'.format(self.config['pdns_postgresql_dbname']),
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# Database name
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'--gpgsql-user={}'.format(self.config['pdns_postgresql_user']),
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# User name
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'--gpgsql-password={}'.format(self.config['pdns_postgresql_password']),
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# User password
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'--gpgsql-dnssec=no', # Do DNSSEC elsewhere
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]
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# Start the pdns process in a thread
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self.dns_server_daemon = common.run_os_daemon(
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'/usr/sbin/pdns_server {}'.format(
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' '.join(dns_configuration)
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),
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environment=None,
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logfile='{}/pdns-aggregator.log'.format(self.config['pdns_log_directory'])
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)
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if self.dns_server_daemon:
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self.logger.out(
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'Successfully started PowerDNS zone aggregator',
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state='o'
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)
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def stop(self):
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if self.dns_server_daemon:
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self.logger.out(
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'Stopping PowerDNS zone aggregator',
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state='i'
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)
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# Terminate, then kill
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self.dns_server_daemon.signal('term')
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time.sleep(0.2)
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self.dns_server_daemon.signal('kill')
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self.logger.out(
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'Successfully stopped PowerDNS zone aggregator',
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state='o'
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)
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class DNSNetworkInstance(object):
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# Initialization function
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def __init__(self, aggregator, network):
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self.aggregator = aggregator
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self.config = self.aggregator.config
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self.logger = self.aggregator.logger
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self.sql_conn = None
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self.network = network
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# Add a new network to the aggregator database
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def add_network(self):
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network_domain = self.network.domain
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if self.network.ip4_gateway != 'None':
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network_gateway = self.network.ip4_gateway
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else:
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network_gateway = self.network.ip6_gateway
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self.logger.out(
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'Adding entry for client domain {}'.format(
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network_domain
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),
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prefix='DNS aggregator',
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state='o'
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)
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# Connect to the database
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self.sql_conn = psycopg2.connect(
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"host='{}' port='{}' dbname='{}' user='{}' password='{}' sslmode='disable'".format(
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self.config['pdns_postgresql_host'],
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self.config['pdns_postgresql_port'],
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self.config['pdns_postgresql_dbname'],
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self.config['pdns_postgresql_user'],
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self.config['pdns_postgresql_password']
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)
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)
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sql_curs = self.sql_conn.cursor()
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# Try to access the domains entry
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sql_curs.execute(
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"SELECT * FROM domains WHERE name=%s",
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(network_domain,)
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)
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results = sql_curs.fetchone()
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# If we got back a result, don't try to add the domain to the DB
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if results:
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write_domain = False
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else:
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write_domain = True
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# Write the domain to the database if we're active
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if self.aggregator.is_active and write_domain:
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sql_curs.execute(
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"INSERT INTO domains (name, type, account, notified_serial) VALUES (%s, 'MASTER', 'internal', 0)",
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(network_domain,)
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)
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self.sql_conn.commit()
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sql_curs.execute(
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"SELECT id FROM domains WHERE name=%s",
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(network_domain,)
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)
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domain_id = sql_curs.fetchone()
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sql_curs.execute(
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"""
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INSERT INTO records (domain_id, name, content, type, ttl, prio) VALUES
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(%s, %s, %s, %s, %s, %s)
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""",
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(domain_id, network_domain, 'nsX.{d} root.{d} 1 10800 1800 86400 86400'.format(d=self.config['cluster_domain']), 'SOA', 86400, 0)
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)
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ns_servers = [network_gateway, 'pvc-ns1.{}'.format(self.config['cluster_domain']), 'pvc-ns2.{}'.format(self.config['cluster_domain'])]
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for ns_server in ns_servers:
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sql_curs.execute(
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"""
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INSERT INTO records (domain_id, name, content, type, ttl, prio) VALUES
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(%s, %s, %s, %s, %s, %s)
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""",
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(domain_id, network_domain, ns_server, 'NS', 86400, 0)
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)
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self.sql_conn.commit()
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self.sql_conn.close()
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self.sql_conn = None
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# Remove a deleted network from the aggregator database
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def remove_network(self):
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network_domain = self.network.domain
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self.logger.out(
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'Removing entry for client domain {}'.format(
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network_domain
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),
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prefix='DNS aggregator',
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state='o'
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)
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# Connect to the database
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self.sql_conn = psycopg2.connect(
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"host='{}' port='{}' dbname='{}' user='{}' password='{}' sslmode='disable'".format(
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self.config['pdns_postgresql_host'],
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self.config['pdns_postgresql_port'],
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self.config['pdns_postgresql_dbname'],
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self.config['pdns_postgresql_user'],
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self.config['pdns_postgresql_password']
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)
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)
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sql_curs = self.sql_conn.cursor()
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# Get the domain ID
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sql_curs.execute(
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"SELECT id FROM domains WHERE name=%s",
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(network_domain,)
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)
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domain_id = sql_curs.fetchone()
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# Delete the domain from the database if we're active
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if self.aggregator.is_active and domain_id:
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sql_curs.execute(
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"DELETE FROM domains WHERE id=%s",
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(domain_id,)
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)
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sql_curs.execute(
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"DELETE FROM records WHERE domain_id=%s",
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(domain_id,)
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)
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self.sql_conn.commit()
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self.sql_conn.close()
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self.sql_conn = None
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class AXFRDaemonInstance(object):
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# Initialization function
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def __init__(self, aggregator):
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self.aggregator = aggregator
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self.config = self.aggregator.config
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self.logger = self.aggregator.logger
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self.dns_networks = self.aggregator.dns_networks
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self.thread_stopper = threading.Event()
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self.thread = None
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self.sql_conn = None
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def update_networks(self, dns_networks):
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self.dns_networks = dns_networks
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def start(self):
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# Create the thread
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self.thread_stopper.clear()
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self.thread = threading.Thread(target=self.run, args=(), kwargs={})
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# Start a local instance of the SQL connection
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# Trying to use the instance from the main DNS Aggregator can result in connection failures
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# after the leader transitions
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self.sql_conn = psycopg2.connect(
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"host='{}' port='{}' dbname='{}' user='{}' password='{}' sslmode='disable'".format(
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self.config['pdns_postgresql_host'],
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self.config['pdns_postgresql_port'],
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self.config['pdns_postgresql_dbname'],
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self.config['pdns_postgresql_user'],
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self.config['pdns_postgresql_password']
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)
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)
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# Start the thread
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self.thread.start()
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def stop(self):
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self.thread_stopper.set()
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if self.sql_conn:
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self.sql_conn.close()
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self.sql_conn = None
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def run(self):
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# Wait for all the DNSMASQ instances to actually start
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time.sleep(5)
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while not self.thread_stopper.is_set():
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# We do this for each network
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for network, instance in self.dns_networks.items():
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zone_modified = False
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# Set up our SQL cursor
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sql_curs = self.sql_conn.cursor()
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# Set up our basic variables
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domain = network.domain
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if network.ip4_gateway != 'None':
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dnsmasq_ip = network.ip4_gateway
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else:
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dnsmasq_ip = network.ip6_gateway
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#
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# Get an AXFR from the dnsmasq instance and list of records
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#
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try:
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axfr = dns.query.xfr(dnsmasq_ip, domain, lifetime=5.0)
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z = dns.zone.from_xfr(axfr)
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records_raw = [z[n].to_text(n) for n in z.nodes.keys()]
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except Exception as e:
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print('{} {} ({})'.format(e, dnsmasq_ip, domain))
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continue
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# Fix the formatting because it's useless
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# reference: ['@ 600 IN SOA . . 4 1200 180 1209600 600\n@ 600 IN NS .', 'test3 600 IN A 10.1.1.203\ntest3 600 IN AAAA 2001:b23e:1113:0:5054:ff:fe5c:f131', etc.]
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# We don't really care about dnsmasq's terrible SOA or NS records which are in [0]
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string_records = '\n'.join(records_raw[1:])
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# Split into individual records
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records_new = list()
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for element in string_records.split('\n'):
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if element:
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record = element.split()
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# Handle space-containing data elements
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if domain not in record[0]:
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name = '{}.{}'.format(record[0], domain)
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else:
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name = record[0]
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entry = '{} {} IN {} {}'.format(name, record[1], record[3], ' '.join(record[4:]))
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records_new.append(entry)
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#
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# Get the current zone from the database
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#
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try:
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sql_curs.execute(
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"SELECT id FROM domains WHERE name=%s",
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(domain,)
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)
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domain_id = sql_curs.fetchone()
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sql_curs.execute(
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"SELECT * FROM records WHERE domain_id=%s",
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(domain_id,)
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)
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results = list(sql_curs.fetchall())
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if self.config['debug']:
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print('SQL query results: {}'.format(results))
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except Exception as e:
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self.logger.out('ERROR: Failed to obtain DNS records from database: {}'.format(e))
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# Fix the formatting because it's useless for comparison
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# reference: ((10, 28, 'testnet01.i.bonilan.net', 'SOA', 'nsX.pvc.local root.pvc.local 1 10800 1800 86400 86400', 86400, 0, None, 0, None, 1), etc.)
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records_old = list()
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records_old_ids = list()
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if not results:
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if self.config['debug']:
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print('No results found, skipping.')
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continue
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for record in results:
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# Skip the non-A
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r_id = record[0]
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r_name = record[2]
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r_ttl = record[5]
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r_type = record[3]
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r_data = record[4]
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# Assemble a list element in the same format as the AXFR data
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entry = '{} {} IN {} {}'.format(r_name, r_ttl, r_type, r_data)
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if self.config['debug']:
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print('Found record: {}'.format(entry))
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# Skip non-A or AAAA records
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if r_type != 'A' and r_type != 'AAAA':
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if self.config['debug']:
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print('Skipping record {}, not A or AAAA: "{}"'.format(entry, r_type))
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continue
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records_old.append(entry)
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records_old_ids.append(r_id)
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records_new.sort()
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records_old.sort()
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if self.config['debug']:
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print('New: {}'.format(records_new))
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print('Old: {}'.format(records_old))
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# Find the differences between the lists
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# Basic check one: are they completely equal
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if records_new != records_old:
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# Get set elements
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in_new = set(records_new)
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in_old = set(records_old)
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in_new_not_in_old = in_new - in_old
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in_old_not_in_new = in_old - in_new
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if self.config['debug']:
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print('New but not old: {}'.format(in_new_not_in_old))
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print('Old but not new: {}'.format(in_old_not_in_new))
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# Go through the old list
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remove_records = list() # list of database IDs
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for i in range(len(records_old)):
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record_id = records_old_ids[i]
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record = records_old[i]
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splitrecord = records_old[i].split()
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# If the record is not in the new list, remove it
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if record in in_old_not_in_new:
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remove_records.append(record_id)
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# Go through the new elements
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for newrecord in in_new_not_in_old:
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splitnewrecord = newrecord.split()
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# If there's a name and type match with different content, remove the old one
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if splitrecord[0] == splitnewrecord[0] and splitrecord[3] == splitnewrecord[3]:
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remove_records.append(record_id)
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changed = False
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if len(remove_records) > 0:
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# Remove the invalid old records
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for record_id in remove_records:
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if self.config['debug']:
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print('Removing record: {}'.format(record_id))
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sql_curs.execute(
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"DELETE FROM records WHERE id=%s",
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(record_id,)
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)
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changed = True
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if len(in_new_not_in_old) > 0:
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# Add the new records
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for record in in_new_not_in_old:
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# [NAME, TTL, 'IN', TYPE, DATA]
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record = record.split()
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r_name = record[0]
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r_ttl = record[1]
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r_type = record[3]
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r_data = record[4]
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if self.config['debug']:
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print('Add record: {}'.format(name))
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sql_curs.execute(
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"INSERT INTO records (domain_id, name, ttl, type, prio, content) VALUES (%s, %s, %s, %s, %s, %s)",
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(domain_id, r_name, r_ttl, r_type, 0, r_data)
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)
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changed = True
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|
if changed:
|
|
# Increase SOA serial
|
|
sql_curs.execute(
|
|
"SELECT content FROM records WHERE domain_id=%s AND type='SOA'",
|
|
(domain_id,)
|
|
)
|
|
soa_record = list(sql_curs.fetchone())[0].split()
|
|
current_serial = int(soa_record[2])
|
|
new_serial = current_serial + 1
|
|
soa_record[2] = str(new_serial)
|
|
if self.config['debug']:
|
|
print('Records changed; bumping SOA: {}'.format(new_serial))
|
|
sql_curs.execute(
|
|
"UPDATE records SET content=%s WHERE domain_id=%s AND type='SOA'",
|
|
(' '.join(soa_record), domain_id)
|
|
)
|
|
|
|
# Commit all the previous changes
|
|
if self.config['debug']:
|
|
print('Committing database changes and reloading PDNS')
|
|
try:
|
|
self.sql_conn.commit()
|
|
except Exception as e:
|
|
self.logger.out('ERROR: Failed to commit DNS aggregator changes: {}'.format(e), state='e')
|
|
|
|
# Reload the domain
|
|
common.run_os_command(
|
|
'/usr/bin/pdns_control --socket-dir={} reload {}'.format(
|
|
self.config['pdns_dynamic_directory'],
|
|
domain
|
|
),
|
|
background=False
|
|
)
|
|
|
|
# Wait for 10 seconds
|
|
time.sleep(10)
|