marcusH
52 lines
2.2 KiB
Python
52 lines
2.2 KiB
Python
from ipaddress import ip_address
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from sys import stderr
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from dns.name import from_text, root
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from dns.resolver import NXDOMAIN, NoAnswer, Resolver, Timeout
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from .provider import DNSProvider
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class DNSPythonProvider(DNSProvider):
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def configure(self, dns_servers, *, bind_addresses=None, search_domains=()):
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super().configure(dns_servers, bind_addresses=bind_addresses, search_domains=search_domains)
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self.resolver = Resolver(configure=False)
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self.resolver.domain = root
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self.resolver.search = [from_text(d) for d in search_domains]
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self.rectypes = []
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if self.bind_addresses is None or any(a.version == 4 for a in self.bind_addresses):
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self.rectypes.append('A')
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if self.bind_addresses is None or any(a.version == 6 for a in self.bind_addresses):
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self.rectypes.append('AAAA')
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def lookup_host(self, hostname, keep_going=True):
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result = set()
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for source in self.bind_addresses or [None]:
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if source is None:
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self.resolver.nameservers = self.dns_servers
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else:
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self.resolver.nameservers = [str(dns) for dns in self.dns_servers if dns.version == source.version]
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if not self.resolver.nameservers:
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continue
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for rectype in self.rectypes:
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try:
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# print("Issuing query for hostname %r, rectype %r, source %r, search %r, nameservers %r" % (
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# hostname, rectype, source, self.resolver.search, self.resolver.nameservers), file=stderr)
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a = self.resolver.query(hostname, rectype, source=None if source is None else str(source))
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print("Got results: %r" % list(a), file=stderr)
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except (NXDOMAIN, NoAnswer):
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pass
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except Timeout:
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# No point in retrying with a different rectype if these DNS server(s) are not responding
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break
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else:
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result.update(ip_address(r.address) for r in a)
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if result and not keep_going:
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return result
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return result or None
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