Rewrite DNSAggregatorInstance to handle DNS well
Trying to directly AXFR from dnsmasq is a mess, since their zone is barely compliant with spec, it doesn't support notifies, and it is generally really messy. This implements an advanced "AXFR parser" system, which looks at the results of an AXFR from the local dnsmasq instances per-network, and updates the real replicated MariaDB pdns backend cluster with the changed data. This allows a sensible, transferable zone with its own SOA that is dynamically reconfigured as hosts come and go from the dnsmasq zone.
This commit is contained in:
@ -23,22 +23,63 @@
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import os
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import sys
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import time
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import sqlite3
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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 MySQLdb as mysqldb
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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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# A barebones PowerDNS sqlite schema (relative to the active dir)
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sql_schema_file = 'pvcd/powerdns-aggregator-schema.sql'
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class DNSAggregatorInstance(object):
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# Initialization function
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def __init__(self, zk_conn, config, logger, d_network):
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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.d_network = d_network
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self.dns_networks = dict()
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self.is_active = False
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self.mysql_conn = mysqldb.connect(
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host=self.config['pdns_mysql_host'],
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port=int(self.config['pdns_mysql_port']),
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user=self.config['pdns_mysql_user'],
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passwd=self.config['pdns_mysql_password'],
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db=self.config['pdns_mysql_dbname']
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)
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self.dns_server_daemon = PowerDNSInstance(self.config, self.logger, self.dns_networks)
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self.dns_axfr_daemon = AXFRDaemonInstance(self.config, self.logger, self.mysql_conn, self.dns_networks)
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# Start up the PowerDNS instance
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def start_aggregator(self):
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self.dns_server_daemon.start()
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self.dns_axfr_daemon.start()
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# Stop the PowerDNS instance
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def stop_aggregator(self):
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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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print("adding {}".format(network))
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self.dns_networks[network] = DNSNetworkInstance(self.config, self.logger, self.mysql_conn, 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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print("removing {}".format(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, config, logger, dns_networks):
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self.config = config
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self.logger = 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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@ -46,113 +87,7 @@ class DNSAggregatorInstance(object):
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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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self.database_file = self.config['pdns_dynamic_directory'] + '/pdns-aggregator.sqlite3'
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self.dns_server_daemon = None
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self.prepare_db()
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# Preparation function
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def prepare_db(self):
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# Connect to the database
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sql_conn = sqlite3.connect(self.database_file)
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sql_curs = sql_conn.cursor()
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# Try to access the domains table
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try:
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sql_curs.execute(
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'select * from domains'
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)
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write_schema = False
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# The table doesn't exist, so we should create it
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except sqlite3.OperationalError:
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write_schema = True
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if write_schema:
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with open('{}/{}'.format(os.getcwd(), sql_schema_file), 'r') as schema_file:
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schema = ''.join(schema_file.readlines())
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sql_curs.executescript(schema)
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sql_conn.close()
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# Add a new network to the aggregator database
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def add_client_network(self, network):
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network_domain = self.d_network[network].domain
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if self.d_network[network].ip4_gateway != 'None':
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network_gateway = self.d_network[network].ip4_gateway
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else:
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network_gateway = self.d_network[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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sql_conn = sqlite3.connect(self.database_file)
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sql_curs = 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=?',
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(network_domain,)
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)
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results = sql_curs.fetchall()
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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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if write_domain:
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sql_curs.execute(
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'insert into domains (name, master, type, account) values (?, ?, "SLAVE", "internal")',
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(network_domain, network_gateway)
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)
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sql_conn.commit()
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sql_conn.close()
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# Remove a deleted network from the aggregator database
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def remove_client_network(self, network):
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network_domain = self.d_network[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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sql_conn = sqlite3.connect(self.database_file)
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sql_curs = sql_conn.cursor()
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sql_curs.execute(
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'delete from domains where name=?',
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(network_domain,)
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)
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sql_conn.commit()
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sql_conn.close()
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# Force AXFR
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def get_axfr(self, network):
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self.logger.out(
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'Perform AXFR for {}'.format(
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self.d_network[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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common.run_os_command(
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'/usr/bin/pdns_control --socket-dir={} retrieve {}'.format(
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self.config['pdns_dynamic_directory'],
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self.d_network[network].domain
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),
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background=True
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)
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# Start up the PowerDNS instance
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def start_aggregator(self):
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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='o'
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@ -166,10 +101,10 @@ class DNSAggregatorInstance(object):
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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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'--also-notify=10.101.0.60', # Notify upstreams
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# '--also-notify=10.101.0.60', # Notify upstreams
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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=10053', # On port 10053
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'--local-port=10053', # On port 10053
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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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@ -179,10 +114,18 @@ class DNSAggregatorInstance(object):
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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=gsqlite3', # Use the sqlite3 backend
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'--gsqlite3-database={}'.format(self.database_file),
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# Database file
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'--gsqlite3-dnssec=no' # Don't do DNSSEC here
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'--launch=gmysql', # Use the MySQL backend
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'--gmysql-host={}'.format(self.config['pdns_mysql_host']),
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# MySQL instance
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'--gmysql-port={}'.format(self.config['pdns_mysql_port']),
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# Default port
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'--gmysql-dbname={}'.format(self.config['pdns_mysql_dbname']),
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# Database name
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'--gmysql-user={}'.format(self.config['pdns_mysql_user']),
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# User name
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'--gmysql-password={}'.format(self.config['pdns_mysql_password']),
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# User password
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'--gmysql-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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@ -193,8 +136,7 @@ class DNSAggregatorInstance(object):
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logfile='{}/pdns-aggregator.log'.format(self.config['pdns_log_directory'])
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)
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# Stop the PowerDNS instance
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def stop_aggregator(self):
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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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@ -204,3 +146,289 @@ class DNSAggregatorInstance(object):
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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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class DNSNetworkInstance(object):
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# Initialization function
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def __init__(self, config, logger, mysql_conn, network):
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self.config = config
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self.logger = logger
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self.mysql_conn = mysql_conn
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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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mysql_curs = self.mysql_conn.cursor()
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# Try to access the domains entry
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mysql_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 = mysql_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
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if write_domain:
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mysql_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.mysql_conn.commit()
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mysql_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 = mysql_curs.fetchone()
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mysql_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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mysql_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.mysql_conn.commit()
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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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mysql_curs = self.mysql_conn.cursor()
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mysql_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 = mysql_curs.fetchone()
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mysql_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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mysql_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.mysql_conn.commit()
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class AXFRDaemonInstance(object):
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# Initialization function
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def __init__(self, config, logger, mysql_conn, dns_networks):
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self.config = config
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self.logger = logger
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self.mysql_conn = mysql_conn
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self.dns_networks = dns_networks
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self.thread_stopper = threading.Event()
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self.thread = 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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self.thread_stopper.clear()
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self.thread = threading.Thread(target=self.run, args=(), kwargs={})
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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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def run(self):
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# Wait for all the DNSMASQ instances to actually start
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time.sleep(2)
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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 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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# Get an AXFR from the dnsmasq instance and list of records
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print('{} {}'.format(dnsmasq_ip, domain))
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try:
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z = dns.zone.from_xfr(dns.query.xfr(dnsmasq_ip, domain, lifetime=5.0))
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records_raw = [z[n].to_text(n) for n in z.nodes.keys()]
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except OSError as e:
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print(e)
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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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# Get the current zone from the database
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mysql_curs = self.mysql_conn.cursor()
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mysql_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 = mysql_curs.fetchone()
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mysql_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(mysql_curs.fetchall())
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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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for record in results:
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# Skip the SOA and NS records
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if record[3] == 'SOA' or record[3] == 'NS':
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continue
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# Assemble a list element in the same format as the AXFR data
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entry = '{} {} IN {} {}'.format(record[2], record[5], record[3], record[4])
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records_old.append(entry)
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records_old_ids.append(record[0])
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records_new.sort()
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records_old.sort()
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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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# 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()
|
||||
# If there's a name match with different content, remove the old one
|
||||
if splitrecord[0] == splitnewrecord[0]:
|
||||
remove_records.append(record_id)
|
||||
|
||||
changed = False
|
||||
if len(remove_records) > 0:
|
||||
print(remove_records)
|
||||
# Remove the invalid old records
|
||||
for record_id in remove_records:
|
||||
mysql_curs = self.mysql_conn.cursor()
|
||||
mysql_curs.execute(
|
||||
'DELETE FROM records WHERE id=%s',
|
||||
(record_id,)
|
||||
)
|
||||
changed = True
|
||||
|
||||
if len(in_new_not_in_old) > 0:
|
||||
print(in_new_not_in_old)
|
||||
# Add the new records
|
||||
for record in in_new_not_in_old:
|
||||
# [NAME, TTL, 'IN', TYPE, DATA]
|
||||
record = record.split()
|
||||
rname = record[0]
|
||||
rttl = record[1]
|
||||
rtype = record[3]
|
||||
rdata = record[4]
|
||||
mysql_curs = self.mysql_conn.cursor()
|
||||
mysql_curs.execute(
|
||||
'INSERT INTO records (domain_id, name, ttl, type, prio, content) VALUES (%s, %s, %s, %s, %s, %s)',
|
||||
(domain_id, rname, rttl, rtype, 0, rdata)
|
||||
)
|
||||
changed = True
|
||||
|
||||
if changed:
|
||||
# Increase SOA serial
|
||||
mysql_curs.execute(
|
||||
'SELECT content FROM records WHERE domain_id=%s AND type="SOA"',
|
||||
(domain_id,)
|
||||
)
|
||||
soa_record = list(mysql_curs.fetchone())[0].split()
|
||||
print(soa_record)
|
||||
current_serial = int(soa_record[2])
|
||||
new_serial = current_serial + 1
|
||||
soa_record[2] = str(new_serial)
|
||||
mysql_curs.execute(
|
||||
'UPDATE records SET content=%s WHERE domain_id=%s AND type="SOA"',
|
||||
(' '.join(soa_record), domain_id)
|
||||
)
|
||||
|
||||
# Commit all the previous changes
|
||||
self.mysql_conn.commit()
|
||||
|
||||
# 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)
|
||||
|
||||
Reference in New Issue
Block a user