* Search for longest-matching domain name instead of first-matching.

[invirt/packages/invirt-dns.git] / code / dnsserver.py

diff --git a/code/dnsserver.py b/code/dnsserver.py
index ee18cca..3036092 100755 (executable)
--- a/code/dnsserver.py
+++ b/code/dnsserver.py
@@ -56,23 +56,41 @@ class DatabaseAuthority(common.ResolverBase):
         
         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='0.0.0.0', ttl=3600), auth=True)
+            return defer.succeed(([], [authority], [additional]))
+
         if name in self.domains:
             domain = name
         else:
-            # This works because domain will remain bound after breaking out of the loop
+            # 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):
-                    break
-            else: #Not us
+                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:
+            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, 
@@ -84,20 +102,20 @@ class DatabaseAuthority(common.ResolverBase):
                 elif type == dns.SOA:
                     results.append(dns.RRHeader(domain, dns.SOA, dns.IN,
                                                 ttl, self.soa, auth=True))
-            else:
+            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)],
                         [], []))
 
-                if host:
-                    value = invirt.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)))
+                value = invirt.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)))
+
                 if type in (dns.A, dns.ALL_RECORDS):
                     record = dns.Record_A(ip, ttl)
                     results.append(dns.RRHeader(name, dns.A, dns.IN,