X-Git-Url: http://xvm.mit.edu/gitweb/invirt/packages/invirt-dns.git/blobdiff_plain/fbabf89bd5bbb2d312d68e8841b692421cb7a08e..9ec49e10b2d8007f27a1741c43dc6aa79dea21ba:/code/dnsserver.py diff --git a/code/dnsserver.py b/code/dnsserver.py old mode 100644 new mode 100755 index 3cc8dc5..9da9eda --- a/code/dnsserver.py +++ b/code/dnsserver.py @@ -7,48 +7,94 @@ from twisted.internet import defer from twisted.python import failure import sipb_xen_database +import psycopg2 +import sqlalchemy +import time class DatabaseAuthority(common.ResolverBase): """An Authority that is loaded from a file.""" soa = None - def __init__(self, domain, database=None): + def __init__(self, domains, database=None): common.ResolverBase.__init__(self) if database is not None: sipb_xen_database.connect(database) - self.domain = domain + self.domains = domains self.soa = dns.Record_SOA(mname='sipb-xen-dev.mit.edu', rname='sipb-xen.mit.edu', serial=1, refresh=3600, retry=900, expire=3600000, minimum=21600, ttl=3600) + self.ns = dns.Record_NS(name='ns1.xvm.mit.edu', ttl=3600) + record = dns.Record_A(address='18.181.0.62', ttl=3600) + self.ns1 = dns.RRHeader('ns1.xvm.mit.edu', dns.A, dns.IN, + 3600, record, auth=True) + + def _lookup(self, name, cls, type, timeout = None): - if not (name.lower() == self.domain or - name.lower().endswith('.'+self.domain)): - #Not us - return defer.fail(failure.Failure(dns.DomainError(name))) + for i in range(3): + try: + value = self._lookup_unsafe(name, cls, type, timeout = None) + except (psycopg2.OperationalError, sqlalchemy.exceptions.SQLError): + if i == 2: + raise + print "Reloading database" + time.sleep(0.5) + continue + else: + return value + + def _lookup_unsafe(self, name, cls, type, timeout): + sipb_xen_database.clear_cache() + + ttl = 900 + name = name.lower() + if name in self.domains: + domain = name + else: + # This works because domain will remain bound after breaking out of the loop + for domain in self.domains: + if name.endswith('.'+domain): + break + else: #Not us + return defer.fail(failure.Failure(dns.DomainError(name))) results = [] - if cls == dns.IN and type in (dns.A, dns.ALL_RECORDS): - host = name[:-len(self.domain)-1] - value = sipb_xen_database.Machine.get_by(name=host) - if value is None or not value.nics: - return defer.fail(failure.Failure(dns.AuthoritativeDomainError(name))) - ip = value.nics[0].ip - if ip is None: #Deactivated? - return defer.fail(failure.Failure(dns.AuthoritativeDomainError(name))) - ttl = 900 - record = dns.Record_A(ip, ttl) - results.append(dns.RRHeader(name, dns.A, dns.IN, - ttl, record, auth=True)) authority = [] - authority.append(dns.RRHeader(self.domain, dns.SOA, dns.IN, 3600, - self.soa, auth=True)) - return defer.succeed((results, authority, [])) - #Doesn't exist - return defer.fail(failure.Failure(dns.AuthoritativeDomainError(name))) + additional = [self.ns1] + authority.append(dns.RRHeader(domain, dns.NS, dns.IN, + 3600, self.ns, auth=True)) + if cls == dns.IN: + if type in (dns.A, dns.ALL_RECORDS): + host = name[:-len(domain)-1] + if not host: + record = dns.Record_A('18.181.0.62', ttl) + results.append(dns.RRHeader(name, dns.A, dns.IN, + ttl, record, auth=True)) + else: + value = sipb_xen_database.Machine.get_by(name=host) + if value is None or not value.nics: + return defer.fail(failure.Failure(dns.AuthoritativeDomainError(name))) + ip = value.nics[0].ip + if ip is None: #Deactivated? + return defer.fail(failure.Failure(dns.AuthoritativeDomainError(name))) + record = dns.Record_A(ip, ttl) + results.append(dns.RRHeader(name, dns.A, dns.IN, + ttl, record, auth=True)) + elif type == dns.NS: + results.append(dns.RRHeader(domain, dns.NS, dns.IN, + ttl, self.ns, auth=True)) + authority = [] + elif type == dns.SOA: + results.append(dns.RRHeader(domain, dns.SOA, dns.IN, + ttl, self.soa, auth=True)) + return defer.succeed((results, authority, additional)) + else: + #Doesn't exist + return defer.fail(failure.Failure(dns.AuthoritativeDomainError(name))) if '__main__' == __name__: - resolver = DatabaseAuthority('servers.csail.mit.edu', + resolver = DatabaseAuthority(['servers.csail.mit.edu', + 'xvm.mit.edu'], 'postgres://sipb-xen@sipb-xen-dev/sipb_xen') verbosity = 0