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