198 lines
8 KiB
Python
198 lines
8 KiB
Python
import logging
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from typing import Optional
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import dns.query
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import dns.rdatatype
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import dns.resolver
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from django.db.models.functions import Length
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from django_rq import job
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from dns import rcode
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from netaddr import ip
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from ipam.models import IPAddress
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from netbox_ddns.models import ACTION_CREATE, ACTION_DELETE, DNSStatus, ReverseZone, Zone
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logger = logging.getLogger('netbox_ddns')
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def get_zone(dns_name: str) -> Optional[Zone]:
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# Generate all possible zones
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zones = []
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parts = dns_name.lower().split('.')
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for i in range(len(parts)):
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zones.append('.'.join(parts[-i - 1:]))
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# Find the zone, if any
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return Zone.objects.filter(name__in=zones).order_by(Length('name').desc()).first()
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def get_soa(dns_name: str) -> str:
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parts = dns_name.rstrip('.').split('.')
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for i in range(len(parts)):
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zone_name = '.'.join(parts[i:]) + '.'
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try:
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dns.resolver.query(zone_name, dns.rdatatype.SOA)
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return zone_name
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except dns.resolver.NoAnswer:
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# The name exists, but has no SOA. Continue one level further up
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continue
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except dns.resolver.NXDOMAIN as e:
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# Look for a SOA record in the authority section
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for query, response in e.responses().items():
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for rrset in response.authority:
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if rrset.rdtype == dns.rdatatype.SOA:
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return rrset.name.to_text()
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def get_reverse_zone(address: ip.IPAddress) -> Optional[ReverseZone]:
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# Find the zone, if any
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zones = list(ReverseZone.objects.filter(prefix__net_contains=address))
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if not zones:
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return None
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zones.sort(key=lambda zone: zone.prefix.prefixlen)
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return zones[-1]
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def status_update(output: list, operation: str, response) -> None:
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code = response.rcode()
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if code == dns.rcode.NOERROR:
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message = f"{operation} successful"
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logger.info(message)
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else:
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message = f"{operation} failed: {dns.rcode.to_text(code)}"
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logger.error(message)
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output.append(message)
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@job
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def update_dns(old_record: IPAddress = None, new_record: IPAddress = None,
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skip_forward=False, skip_reverse=False):
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old_address = old_record.address.ip if old_record else None
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new_address = new_record.address.ip if new_record else None
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old_dns_name = old_record.dns_name.rstrip('.') + '.' if old_record and old_record.dns_name else ''
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new_dns_name = new_record.dns_name.rstrip('.') + '.' if new_record and new_record.dns_name else ''
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output = []
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status, created = DNSStatus.objects.get_or_create(ip_address=new_record or old_record)
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# Only delete old records when they are provided and not the same as the new records
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if old_dns_name and old_address and (old_dns_name != new_dns_name or old_address != new_address):
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# Delete old forward record
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if not skip_forward:
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zone = get_zone(old_dns_name)
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if zone:
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logger.debug(f"Found zone {zone.name} for {old_dns_name}")
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status.forward_action = ACTION_DELETE
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# Check the SOA, we don't want to write to a parent zone if it has delegated authority
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soa = get_soa(old_dns_name)
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if soa == zone.name:
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update = zone.server.create_update(zone.name)
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update.delete(
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old_dns_name,
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'a' if old_address.version == 4 else 'aaaa',
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str(old_address)
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)
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response = dns.query.udp(update, zone.server.address)
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status_update(output, f'Deleting {old_dns_name} {old_address}', response)
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status.forward_rcode = response.rcode()
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else:
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logger.warning(f"Can't update zone {zone.name} for {old_dns_name}, "
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f"it has delegated authority for {soa}")
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status.forward_rcode = rcode.NOTAUTH
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else:
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logger.debug(f"No zone found for {old_dns_name}")
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# Delete old reverse record
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if not skip_reverse:
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zone = get_reverse_zone(old_address)
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if zone and old_dns_name:
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record_name = zone.record_name(old_address)
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logger.debug(f"Found zone {zone.name} for {record_name}")
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status.reverse_action = ACTION_DELETE
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# Check the SOA, we don't want to write to a parent zone if it has delegated authority
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soa = get_soa(record_name)
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if soa == zone.name:
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update = zone.server.create_update(zone.name)
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update.delete(
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record_name,
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'ptr',
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old_dns_name
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)
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response = dns.query.udp(update, zone.server.address)
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status_update(output, f'Deleting {record_name} {old_dns_name}', response)
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status.reverse_rcode = response.rcode()
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else:
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logger.warning(f"Can't update zone {zone.name} for {record_name}, "
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f"it has delegated authority for {soa}")
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status.reverse_rcode = rcode.NOTAUTH
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else:
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logger.debug(f"No zone found for {old_address}")
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# Always try to add, just in case a previous update failed
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if new_dns_name and new_address:
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# Add new forward record
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if not skip_forward:
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zone = get_zone(new_dns_name)
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if zone:
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logger.debug(f"Found zone {zone.name} for {new_dns_name}")
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status.forward_action = ACTION_CREATE
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# Check the SOA, we don't want to write to a parent zone if it has delegated authority
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soa = get_soa(new_dns_name)
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if soa == zone.name:
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update = zone.server.create_update(zone.name)
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update.add(
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new_dns_name,
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zone.ttl,
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'a' if new_address.version == 4 else 'aaaa',
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str(new_address)
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)
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response = dns.query.udp(update, zone.server.address)
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status_update(output, f'Adding {new_dns_name} {new_address}', response)
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status.forward_rcode = response.rcode()
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else:
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logger.warning(f"Can't update zone {zone.name} for {old_dns_name}, "
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f"it has delegated authority for {soa}")
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status.forward_rcode = rcode.NOTAUTH
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else:
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logger.debug(f"No zone found for {new_dns_name}")
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# Add new reverse record
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if not skip_reverse:
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zone = get_reverse_zone(new_address)
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if zone and new_dns_name:
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record_name = zone.record_name(new_address)
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logger.debug(f"Found zone {zone.name} for {record_name}")
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status.reverse_action = ACTION_CREATE
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# Check the SOA, we don't want to write to a parent zone if it has delegated authority
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soa = get_soa(record_name)
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if soa == zone.name:
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update = zone.server.create_update(zone.name)
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update.add(
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record_name,
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zone.ttl,
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'ptr',
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new_dns_name
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)
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response = dns.query.udp(update, zone.server.address)
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status_update(output, f'Adding {record_name} {new_dns_name}', response)
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status.reverse_rcode = response.rcode()
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else:
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logger.warning(f"Can't update zone {zone.name} for {record_name}, "
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f"it has delegated authority for {soa}")
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status.reverse_rcode = rcode.NOTAUTH
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else:
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logger.debug(f"No zone found for {new_address}")
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# Store the status
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status.save()
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return ', '.join(output)
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