X-Git-Url: http://xvm.mit.edu/gitweb/invirt/packages/invirt-dns.git/blobdiff_plain/c222800f93e407a18292cab69564b24ac0965459..58148f6341dcefbf0b13efc8e76b0fc3be306949:/files/usr/sbin/invirt-dns

diff --git a/files/usr/sbin/invirt-dns b/files/usr/sbin/invirt-dns
new file mode 100755
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--- /dev/null
+++ b/files/usr/sbin/invirt-dns
@@ -0,0 +1,144 @@
+#!/usr/bin/python
+from twisted.internet import reactor
+from twisted.names import server
+from twisted.names import dns
+from twisted.names import common
+from twisted.internet import defer
+from twisted.python import failure
+
+from invirt.config import structs as config
+import invirt.database
+import psycopg2
+import sqlalchemy
+import time
+
+class DatabaseAuthority(common.ResolverBase):
+    """An Authority that is loaded from a file."""
+
+    soa = None
+
+    def __init__(self, domains=None, database=None):
+        common.ResolverBase.__init__(self)
+        if database is not None:
+            invirt.database.connect(database)
+        else:
+            invirt.database.connect()
+        if domains is not None:
+            self.domains = domains
+        else:
+            self.domains = config.dns.domains
+        ns = config.dns.nameservers[0]
+        self.soa = dns.Record_SOA(mname=ns.hostname,
+                                  rname=config.dns.contact.replace('@','.',1),
+                                  serial=1, refresh=3600, retry=900,
+                                  expire=3600000, minimum=21600, ttl=3600)
+        self.ns = dns.Record_NS(name=ns.hostname, ttl=3600)
+        record = dns.Record_A(address=ns.ip, ttl=3600)
+        self.ns1 = dns.RRHeader(ns.hostname, dns.A, dns.IN,
+                                3600, record, auth=True)
+
+    
+    def _lookup(self, name, cls, type, timeout = None):
+        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):
+        invirt.database.clear_cache()
+        
+        ttl = 900
+        name = name.lower()
+
+        # XXX hack for the transition to two separate dev/prod clusters
+        if 'dev.xvm.mit.edu' in self.domains and name.endswith('prod.xvm.mit.edu'):
+            # import time, sys
+            # print time.localtime(), 'handling prod request', name
+            # sys.stdout.flush()
+
+            # Point the client in the right direction for prod requests.
+            authority = dns.RRHeader('prod.xvm.mit.edu', dns.NS, dns.IN, 3600,
+                    dns.Record_NS(name='ns1.prod.xvm.mit.edu', ttl=3600), auth=True)
+            additional = dns.RRHeader('ns1.prod.xvm.mit.edu', dns.A, dns.IN, 3600,
+                    dns.Record_A(address='18.181.0.221', ttl=3600), auth=True)
+            return defer.succeed(([], [authority], [additional]))
+
+        if name in self.domains:
+            domain = name
+        else:
+            # Look for the longest-matching domain.  (This works because domain
+            # will remain bound after breaking out of the loop.)
+            best_domain = ''
+            for domain in self.domains:
+                if name.endswith('.'+domain) and len(domain) > len(best_domain):
+                    best_domain = domain
+            if best_domain == '':
+                return defer.fail(failure.Failure(dns.DomainError(name)))
+            domain = best_domain
+        results = []
+        authority = []
+        additional = [self.ns1]
+        authority.append(dns.RRHeader(domain, dns.NS, dns.IN,
+                                      3600, self.ns, auth=True))
+
+        if cls == dns.IN:
+            host = name[:-len(domain)-1]
+            if not host: # Request for the domain itself.
+                if type in (dns.A, dns.ALL_RECORDS):
+                    record = dns.Record_A(config.dns.nameservers[0].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))
+            else: # Request for a subdomain.
+                if 'passup' in dir(config.dns) and host in config.dns.passup:
+                    record = dns.Record_CNAME('%s.%s' % (host, config.dns.parent), ttl)
+                    return defer.succeed((
+                        [dns.RRHeader(name, dns.CNAME, dns.IN, ttl, record, auth=True)],
+                        [], []))
+
+                value = invirt.database.Machine.query().filter_by(name=host).one()
+                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)))
+
+                if type in (dns.A, dns.ALL_RECORDS):
+                    record = dns.Record_A(ip, ttl)
+                    results.append(dns.RRHeader(name, dns.A, dns.IN, 
+                                                ttl, record, auth=True))
+                elif type == dns.SOA:
+                    results.append(dns.RRHeader(domain, dns.SOA, dns.IN,
+                                                ttl, self.soa, auth=True))
+            if len(results) == 0:
+                authority = []
+                additional = []
+            return defer.succeed((results, authority, additional))
+        else:
+            #Doesn't exist
+            return defer.fail(failure.Failure(dns.AuthoritativeDomainError(name)))
+
+if '__main__' == __name__:
+    resolver = DatabaseAuthority()
+
+    verbosity = 0
+    f = server.DNSServerFactory(authorities=[resolver], verbose=verbosity)
+    p = dns.DNSDatagramProtocol(f)
+    f.noisy = p.noisy = verbosity
+    
+    reactor.listenUDP(53, p)
+    reactor.listenTCP(53, f)
+    reactor.run()