2 from twisted.internet import reactor
3 from twisted.names import server
4 from twisted.names import dns
5 from twisted.names import common
6 from twisted.internet import defer
7 from twisted.python import failure
9 import sipb_xen_database
14 class DatabaseAuthority(common.ResolverBase):
15 """An Authority that is loaded from a file."""
19 def __init__(self, domains, database=None):
20 common.ResolverBase.__init__(self)
21 if database is not None:
22 sipb_xen_database.connect(database)
23 self.domains = domains
24 self.soa = dns.Record_SOA(mname='sipb-xen-dev.mit.edu',
25 rname='sipb-xen.mit.edu',
26 serial=1, refresh=3600, retry=900,
27 expire=3600000, minimum=21600, ttl=3600)
28 self.ns = dns.Record_NS(name='ns1.xvm.mit.edu', ttl=3600)
29 record = dns.Record_A(address='18.181.0.62', ttl=3600)
30 self.ns1 = dns.RRHeader('ns1.xvm.mit.edu', dns.A, dns.IN,
31 3600, record, auth=True)
34 def _lookup(self, name, cls, type, timeout = None):
37 value = self._lookup_unsafe(name, cls, type, timeout = None)
38 except (psycopg2.OperationalError, sqlalchemy.exceptions.SQLError):
41 print "Reloading database"
47 def _lookup_unsafe(self, name, cls, type, timeout):
48 sipb_xen_database.clear_cache()
52 if name in self.domains:
55 # This works because domain will remain bound after breaking out of the loop
56 for domain in self.domains:
57 if name.endswith('.'+domain):
60 return defer.fail(failure.Failure(dns.DomainError(name)))
63 additional = [self.ns1]
64 authority.append(dns.RRHeader(domain, dns.NS, dns.IN,
65 3600, self.ns, auth=True))
67 host = name[:-len(domain)-1]
69 if type in (dns.A, dns.ALL_RECORDS):
70 record = dns.Record_A('18.181.0.62', ttl)
71 results.append(dns.RRHeader(name, dns.A, dns.IN,
72 ttl, record, auth=True))
74 results.append(dns.RRHeader(domain, dns.NS, dns.IN,
75 ttl, self.ns, auth=True))
78 results.append(dns.RRHeader(domain, dns.SOA, dns.IN,
79 ttl, self.soa, auth=True))
82 value = sipb_xen_database.Machine.get_by(name=host)
83 if value is None or not value.nics:
84 return defer.fail(failure.Failure(dns.AuthoritativeDomainError(name)))
86 if ip is None: #Deactivated?
87 return defer.fail(failure.Failure(dns.AuthoritativeDomainError(name)))
88 if type in (dns.A, dns.ALL_RECORDS):
89 record = dns.Record_A(ip, ttl)
90 results.append(dns.RRHeader(name, dns.A, dns.IN,
91 ttl, record, auth=True))
93 results.append(dns.RRHeader(domain, dns.SOA, dns.IN,
94 ttl, self.soa, auth=True))
98 return defer.succeed((results, authority, additional))
101 return defer.fail(failure.Failure(dns.AuthoritativeDomainError(name)))
103 if '__main__' == __name__:
104 resolver = DatabaseAuthority(['servers.csail.mit.edu',
106 'postgres://sipb-xen@sipb-xen-dev/sipb_xen')
109 f = server.DNSServerFactory(authorities=[resolver], verbose=verbosity)
110 p = dns.DNSDatagramProtocol(f)
111 f.noisy = p.noisy = verbosity
113 reactor.listenUDP(53, p)
114 reactor.listenTCP(53, f)