source: trunk/dns/dnsserver.py @ 245

Last change on this file since 245 was 226, checked in by ecprice, 17 years ago

Use the machine name, not the hostname, field.

File size: 2.4 KB
Line 
1#!/usr/bin/python
2from twisted.internet import reactor
3from twisted.names import server
4from twisted.names import dns
5from twisted.names import common
6from twisted.internet import defer
7from twisted.python import failure
8
9import sipb_xen_database
10
11class DatabaseAuthority(common.ResolverBase):
12    """An Authority that is loaded from a file."""
13
14    soa = None
15
16    def __init__(self, domain, database=None):
17        common.ResolverBase.__init__(self)
18        if database is not None:
19            sipb_xen_database.connect(database)
20        self.domain = domain
21        self.soa = dns.Record_SOA(mname='sipb-xen-dev.mit.edu', 
22                                  rname='sipb-xen.mit.edu',
23                                  serial=1, refresh=3600, retry=900,
24                                  expire=3600000, minimum=21600, ttl=3600)
25    def _lookup(self, name, cls, type, timeout = None):
26        if not (name.lower() == self.domain or 
27                name.lower().endswith('.'+self.domain)):
28            #Not us
29            return defer.fail(failure.Failure(dns.DomainError(name)))
30        results = []
31        if cls == dns.IN and type in (dns.A, dns.ALL_RECORDS):
32            host = name[:-len(self.domain)-1]
33            value = sipb_xen_database.Machine.get_by(name=host)
34            if value is None or not value.nics:
35                return defer.fail(failure.Failure(dns.AuthoritativeDomainError(name)))
36            ip = value.nics[0].ip
37            if ip is None:  #Deactivated?
38                return defer.fail(failure.Failure(dns.AuthoritativeDomainError(name)))
39            ttl = 900
40            record = dns.Record_A(ip, ttl)
41            results.append(dns.RRHeader(name, dns.A, dns.IN, 
42                                        ttl, record, auth=True))
43        authority = []
44        authority.append(dns.RRHeader(self.domain, dns.SOA, dns.IN, 3600,
45                                      self.soa, auth=True))
46        return defer.succeed((results, authority, []))
47        #Doesn't exist
48        return defer.fail(failure.Failure(dns.AuthoritativeDomainError(name)))
49
50if '__main__' == __name__:
51    resolver = DatabaseAuthority('servers.csail.mit.edu',
52                                 'postgres://sipb-xen@sipb-xen-dev/sipb_xen')
53
54    verbosity = 0
55    f = server.DNSServerFactory(authorities=[resolver], verbose=verbosity)
56    p = dns.DNSDatagramProtocol(f)
57    f.noisy = p.noisy = verbosity
58   
59    reactor.listenUDP(53, p)
60    reactor.listenTCP(53, f)
61    reactor.run()
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