#!/usr/bin/env python3 # DNSAggregatorInstance.py - Class implementing a DNS aggregator and run by pvcnoded # Part of the Parallel Virtual Cluster (PVC) system # # Copyright (C) 2018-2020 Joshua M. Boniface # # This program is free software: you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation, either version 3 of the License, or # (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program. If not, see . # ############################################################################### import time import dns.zone import dns.query import psycopg2 from threading import Thread, Event import pvcnoded.log as log import pvcnoded.zkhandler as zkhandler import pvcnoded.common as common class DNSAggregatorInstance(object): # Initialization function def __init__(self, zk_conn, config, logger): self.zk_conn = zk_conn self.config = config self.logger = logger self.dns_networks = dict() self.is_active = False self.dns_server_daemon = PowerDNSInstance(self) self.dns_axfr_daemon = AXFRDaemonInstance(self) # Start up the PowerDNS instance def start_aggregator(self): # Restart the SQL connection self.dns_server_daemon.start() self.dns_axfr_daemon.start() self.is_active = True # Stop the PowerDNS instance def stop_aggregator(self): self.is_active = False self.dns_axfr_daemon.stop() self.dns_server_daemon.stop() def add_network(self, network): self.dns_networks[network] = DNSNetworkInstance(self, network) self.dns_networks[network].add_network() self.dns_axfr_daemon.update_networks(self.dns_networks) def remove_network(self, network): if self.dns_networks[network]: self.dns_networks[network].remove_network() del self.dns_networks[network] self.dns_axfr_daemon.update_networks(self.dns_networks) class PowerDNSInstance(object): # Initialization function def __init__(self, aggregator): self.aggregator = aggregator self.config = self.aggregator.config self.logger = self.aggregator.logger self.dns_server_daemon = None # Floating upstreams self.vni_ipaddr, self.vni_cidrnetmask = self.config['vni_floating_ip'].split('/') self.upstream_ipaddr, self.upstream_cidrnetmask = self.config['upstream_floating_ip'].split('/') def start(self): self.logger.out( 'Starting PowerDNS zone aggregator', state='i' ) # Define the PowerDNS config dns_configuration = [ # Option # Explanation '--no-config', '--daemon=no', # Start directly '--guardian=yes', # Use a guardian '--disable-syslog=yes', # Log only to stdout (which is then captured) '--disable-axfr=no', # Allow AXFRs '--allow-axfr-ips=0.0.0.0/0', # Allow AXFRs to anywhere '--local-address={},{}'.format(self.vni_ipaddr, self.upstream_ipaddr), # Listen on floating IPs '--local-port=53', # On port 53 '--log-dns-details=on', # Log details '--loglevel=3', # Log info '--master=yes', # Enable master mode '--slave=yes', # Enable slave mode '--slave-renotify=yes', # Renotify out for our slaved zones '--version-string=powerdns', # Set the version string '--default-soa-name=dns.pvc.local', # Override dnsmasq's invalid name '--socket-dir={}'.format(self.config['pdns_dynamic_directory']), # Standard socket directory '--launch=gpgsql', # Use the PostgreSQL backend '--gpgsql-host={}'.format(self.config['pdns_postgresql_host']), # PostgreSQL instance '--gpgsql-port={}'.format(self.config['pdns_postgresql_port']), # Default port '--gpgsql-dbname={}'.format(self.config['pdns_postgresql_dbname']), # Database name '--gpgsql-user={}'.format(self.config['pdns_postgresql_user']), # User name '--gpgsql-password={}'.format(self.config['pdns_postgresql_password']), # User password '--gpgsql-dnssec=no', # Do DNSSEC elsewhere ] # Start the pdns process in a thread self.dns_server_daemon = common.run_os_daemon( '/usr/sbin/pdns_server {}'.format( ' '.join(dns_configuration) ), environment=None, logfile='{}/pdns-aggregator.log'.format(self.config['pdns_log_directory']) ) if self.dns_server_daemon: self.logger.out( 'Successfully started PowerDNS zone aggregator', state='o' ) def stop(self): if self.dns_server_daemon: self.logger.out( 'Stopping PowerDNS zone aggregator', state='i' ) # Terminate, then kill self.dns_server_daemon.signal('term') time.sleep(0.2) self.dns_server_daemon.signal('kill') self.logger.out( 'Successfully stopped PowerDNS zone aggregator', state='o' ) class DNSNetworkInstance(object): # Initialization function def __init__(self, aggregator, network): self.aggregator = aggregator self.config = self.aggregator.config self.logger = self.aggregator.logger self.sql_conn = None self.network = network # Add a new network to the aggregator database def add_network(self): network_domain = self.network.domain if self.network.ip4_gateway != 'None': network_gateway = self.network.ip4_gateway else: network_gateway = self.network.ip6_gateway self.logger.out( 'Adding entry for client domain {}'.format( network_domain ), prefix='DNS aggregator', state='o' ) # Connect to the database self.sql_conn = psycopg2.connect( "host='{}' port='{}' dbname='{}' user='{}' password='{}' sslmode='disable'".format( self.config['pdns_postgresql_host'], self.config['pdns_postgresql_port'], self.config['pdns_postgresql_dbname'], self.config['pdns_postgresql_user'], self.config['pdns_postgresql_password'] ) ) sql_curs = self.sql_conn.cursor() # Try to access the domains entry sql_curs.execute( "SELECT * FROM domains WHERE name=%s", (network_domain,) ) results = sql_curs.fetchone() # If we got back a result, don't try to add the domain to the DB if results: write_domain = False else: write_domain = True # Write the domain to the database if we're active if self.aggregator.is_active and write_domain: sql_curs.execute( "INSERT INTO domains (name, type, account, notified_serial) VALUES (%s, 'MASTER', 'internal', 0)", (network_domain,) ) self.sql_conn.commit() sql_curs.execute( "SELECT id FROM domains WHERE name=%s", (network_domain,) ) domain_id = sql_curs.fetchone() sql_curs.execute( """ INSERT INTO records (domain_id, name, content, type, ttl, prio) VALUES (%s, %s, %s, %s, %s, %s) """, (domain_id, network_domain, 'nsX.{d} root.{d} 1 10800 1800 86400 86400'.format(d=self.config['upstream_domain']), 'SOA', 86400, 0) ) if self.network.name_servers: ns_servers = self.network.name_servers else: ns_servers = ['pvc-dns.{}'.format(self.config['upstream_domain'])] for ns_server in ns_servers: sql_curs.execute( """ INSERT INTO records (domain_id, name, content, type, ttl, prio) VALUES (%s, %s, %s, %s, %s, %s) """, (domain_id, network_domain, ns_server, 'NS', 86400, 0) ) self.sql_conn.commit() self.sql_conn.close() self.sql_conn = None # Remove a deleted network from the aggregator database def remove_network(self): network_domain = self.network.domain self.logger.out( 'Removing entry for client domain {}'.format( network_domain ), prefix='DNS aggregator', state='o' ) # Connect to the database self.sql_conn = psycopg2.connect( "host='{}' port='{}' dbname='{}' user='{}' password='{}' sslmode='disable'".format( self.config['pdns_postgresql_host'], self.config['pdns_postgresql_port'], self.config['pdns_postgresql_dbname'], self.config['pdns_postgresql_user'], self.config['pdns_postgresql_password'] ) ) sql_curs = self.sql_conn.cursor() # Get the domain ID sql_curs.execute( "SELECT id FROM domains WHERE name=%s", (network_domain,) ) domain_id = sql_curs.fetchone() # Delete the domain from the database if we're active if self.aggregator.is_active and domain_id: sql_curs.execute( "DELETE FROM domains WHERE id=%s", (domain_id,) ) sql_curs.execute( "DELETE FROM records WHERE domain_id=%s", (domain_id,) ) self.sql_conn.commit() self.sql_conn.close() self.sql_conn = None class AXFRDaemonInstance(object): # Initialization function def __init__(self, aggregator): self.aggregator = aggregator self.config = self.aggregator.config self.logger = self.aggregator.logger self.dns_networks = self.aggregator.dns_networks self.thread_stopper = Event() self.thread = None self.sql_conn = None def update_networks(self, dns_networks): self.dns_networks = dns_networks def start(self): # Create the thread self.thread_stopper.clear() self.thread = Thread(target=self.run, args=(), kwargs={}) # Start a local instance of the SQL connection # Trying to use the instance from the main DNS Aggregator can result in connection failures # after the leader transitions self.sql_conn = psycopg2.connect( "host='{}' port='{}' dbname='{}' user='{}' password='{}' sslmode='disable'".format( self.config['pdns_postgresql_host'], self.config['pdns_postgresql_port'], self.config['pdns_postgresql_dbname'], self.config['pdns_postgresql_user'], self.config['pdns_postgresql_password'] ) ) # Start the thread self.thread.start() def stop(self): self.thread_stopper.set() if self.sql_conn: self.sql_conn.close() self.sql_conn = None def run(self): # Wait for all the DNSMASQ instances to actually start time.sleep(5) while not self.thread_stopper.is_set(): # We do this for each network for network, instance in self.dns_networks.items(): zone_modified = False # Set up our SQL cursor try: sql_curs = self.sql_conn.cursor() except Exception: time.sleep(0.5) continue # Set up our basic variables domain = network.domain if network.ip4_gateway != 'None': dnsmasq_ip = network.ip4_gateway else: dnsmasq_ip = network.ip6_gateway # # Get an AXFR from the dnsmasq instance and list of records # try: axfr = dns.query.xfr(dnsmasq_ip, domain, lifetime=5.0) z = dns.zone.from_xfr(axfr) records_raw = [z[n].to_text(n) for n in z.nodes.keys()] except Exception as e: if self.config['debug']: self.logger.out('{} {} ({})'.format(e, dnsmasq_ip, domain), state='d', prefix='dns-aggregator') continue # Fix the formatting because it's useless # 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.] # We don't really care about dnsmasq's terrible SOA or NS records which are in [0] string_records = '\n'.join(records_raw[1:]) # Split into individual records records_new = list() for element in string_records.split('\n'): if element: record = element.split() # Handle space-containing data elements if domain not in record[0]: name = '{}.{}'.format(record[0], domain) else: name = record[0] entry = '{} {} IN {} {}'.format(name, record[1], record[3], ' '.join(record[4:])) records_new.append(entry) # # Get the current zone from the database # try: sql_curs.execute( "SELECT id FROM domains WHERE name=%s", (domain,) ) domain_id = sql_curs.fetchone() sql_curs.execute( "SELECT * FROM records WHERE domain_id=%s", (domain_id,) ) results = list(sql_curs.fetchall()) if self.config['debug']: self.logger.out('SQL query results: {}'.format(results), state='d', prefix='dns-aggregator') except Exception as e: self.logger.out('ERROR: Failed to obtain DNS records from database: {}'.format(e)) # Fix the formatting because it's useless for comparison # 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.) records_old = list() records_old_ids = list() if not results: if self.config['debug']: self.logger.out('No results found, skipping.', state='d', prefix='dns-aggregator') continue for record in results: # Skip the non-A r_id = record[0] r_name = record[2] r_ttl = record[5] r_type = record[3] r_data = record[4] # Assemble a list element in the same format as the AXFR data entry = '{} {} IN {} {}'.format(r_name, r_ttl, r_type, r_data) if self.config['debug']: self.logger.out('Found record: {}'.format(entry), state='d', prefix='dns-aggregator') # Skip non-A or AAAA records if r_type != 'A' and r_type != 'AAAA': if self.config['debug']: self.logger.out('Skipping record {}, not A or AAAA: "{}"'.format(entry, r_type), state='d', prefix='dns-aggregator') continue records_old.append(entry) records_old_ids.append(r_id) records_new.sort() records_old.sort() if self.config['debug']: self.logger.out('New: {}'.format(records_new), state='d', prefix='dns-aggregator') self.logger.out('Old: {}'.format(records_old), state='d', prefix='dns-aggregator') # Find the differences between the lists # Basic check one: are they completely equal if records_new != records_old: # Get set elements in_new = set(records_new) in_old = set(records_old) in_new_not_in_old = in_new - in_old in_old_not_in_new = in_old - in_new if self.config['debug']: self.logger.out('New but not old: {}'.format(in_new_not_in_old), state='d', prefix='dns-aggregator') self.logger.out('Old but not new: {}'.format(in_old_not_in_new), state='d', prefix='dns-aggregator') # Go through the old list remove_records = list() # list of database IDs for i in range(len(records_old)): record_id = records_old_ids[i] record = records_old[i] splitrecord = records_old[i].split() # If the record is not in the new list, remove it if record in in_old_not_in_new: remove_records.append(record_id) # Go through the new elements for newrecord in in_new_not_in_old: splitnewrecord = newrecord.split() # If there's a name and type match with different content, remove the old one if splitrecord[0] == splitnewrecord[0] and splitrecord[3] == splitnewrecord[3]: remove_records.append(record_id) changed = False if len(remove_records) > 0: # Remove the invalid old records for record_id in remove_records: if self.config['debug']: self.logger.out('Removing record: {}'.format(record_id), state='d', prefix='dns-aggregator') sql_curs.execute( "DELETE FROM records WHERE id=%s", (record_id,) ) changed = True if len(in_new_not_in_old) > 0: # Add the new records for record in in_new_not_in_old: # [NAME, TTL, 'IN', TYPE, DATA] record = record.split() r_name = record[0] r_ttl = record[1] r_type = record[3] r_data = record[4] if self.config['debug']: self.logger.out('Add record: {}'.format(name), state='d', prefix='dns-aggregator') try: sql_curs.execute( "INSERT INTO records (domain_id, name, ttl, type, prio, content) VALUES (%s, %s, %s, %s, %s, %s)", (domain_id, r_name, r_ttl, r_type, 0, r_data) ) changed = True except psycopg2.IntegrityError as e: if self.config['debug']: self.logger.out('Failed to add record due to {}: {}'.format(e, name), state='d', prefix='dns-aggregator') 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']: self.logger.out('Records changed; bumping SOA: {}'.format(new_serial), state='d', prefix='dns-aggregator') 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']: self.logger.out('Committing database changes and reloading PDNS', state='d', prefix='dns-aggregator') 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)