From: Greg Price <price@mit.edu>
Date: Fri, 27 Feb 2009 09:38:33 +0000 (-0500)
Subject: pull out dns.IN, comment the structure of the DNS logic
X-Git-Tag: 0.0.11~1
X-Git-Url: http://xvm.mit.edu/gitweb/invirt/packages/invirt-dns.git/commitdiff_plain/56cffcd902204e35cc28915efb27eea559a6618d

pull out dns.IN, comment the structure of the DNS logic

svn path=/trunk/packages/invirt-dns/; revision=2209
---

diff --git a/invirt-dns b/invirt-dns
index 1744ac8..d5fa021 100755
--- a/invirt-dns
+++ b/invirt-dns
@@ -81,65 +81,71 @@ class DatabaseAuthority(common.ResolverBase):
         authority.append(dns.RRHeader(domain, dns.NS, dns.IN,
                                       3600, self.ns, auth=True))
 
-        if cls == dns.IN:
-            if name.endswith(".in-addr.arpa"):
-                if type in (dns.PTR, dns.ALL_RECORDS):
-                    ip = '.'.join(reversed(name.split('.')[:-2]))
-                    value = invirt.database.NIC.query.filter_by(ip=ip).first()
-                    if value and value.hostname:
-                        hostname = value.hostname
-                        if '.' not in hostname:
-                            hostname = hostname + "." + config.dns.domains[0]
-                        record = dns.Record_PTR(hostname, ttl)
-                        results.append(dns.RRHeader(name, dns.PTR, dns.IN,
-                                                    ttl, record, auth=True))
-                    else: # IP address doesn't point to an active host
-                        return defer.fail(failure.Failure(dns.AuthoritativeDomainError(name)))
-                elif type == dns.SOA:
-                    results.append(dns.RRHeader(domain, dns.SOA, dns.IN,
-                                                ttl, self.soa, auth=True))
-                # FIXME: Should only return success with no records if the name actually exists
-            elif name == domain or name == '.'+domain:
-                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:
-                host = name[:-len(domain)-1]
-                value = invirt.database.NIC.query.filter_by(hostname=host).first()
-                if value:
-                    ip = value.ip
-                else:
-                    value = invirt.database.Machine.query().filter_by(name=host).first()
-                    if value:
-                        ip = value.nics[0].ip
-                    else:
-                        return defer.fail(failure.Failure(dns.AuthoritativeDomainError(name)))
+        # The order of logic:
+        # - What class?
+        # - What domain: in-addr.arpa, domain root, or subdomain?
+        # - What query type: A, PTR, NS, ...?
 
-                if ip is None:
-                    return defer.fail(failure.Failure(dns.AuthoritativeDomainError(name)))
+        if cls != dns.IN:
+            # Hahaha.  No.
+            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,
+        if name.endswith(".in-addr.arpa"):
+            if type in (dns.PTR, dns.ALL_RECORDS):
+                ip = '.'.join(reversed(name.split('.')[:-2]))
+                value = invirt.database.NIC.query.filter_by(ip=ip).first()
+                if value and value.hostname:
+                    hostname = value.hostname
+                    if '.' not in hostname:
+                        hostname = hostname + "." + config.dns.domains[0]
+                    record = dns.Record_PTR(hostname, ttl)
+                    results.append(dns.RRHeader(name, dns.PTR, 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:
+                else: # IP address doesn't point to an active host
+                    return defer.fail(failure.Failure(dns.AuthoritativeDomainError(name)))
+            elif type == dns.SOA:
+                results.append(dns.RRHeader(domain, dns.SOA, dns.IN,
+                                            ttl, self.soa, auth=True))
+            # FIXME: Should only return success with no records if the name actually exists
+
+        elif name == domain or name == '.'+domain:
+            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 = []
-                additional = []
-            return defer.succeed((results, authority, additional))
+            elif type == dns.SOA:
+                results.append(dns.RRHeader(domain, dns.SOA, dns.IN,
+                                            ttl, self.soa, auth=True))
+
         else:
-            #Doesn't exist
-            return defer.fail(failure.Failure(dns.AuthoritativeDomainError(name)))
+            host = name[:-len(domain)-1]
+            value = invirt.database.NIC.query.filter_by(hostname=host).first()
+            if value:
+                ip = value.ip
+            else:
+                value = invirt.database.Machine.query().filter_by(name=host).first()
+                if value:
+                    ip = value.nics[0].ip
+                else:
+                    return defer.fail(failure.Failure(dns.AuthoritativeDomainError(name)))
+            if ip is None:
+                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))
 
 class QuotingBindAuthority(authority.BindAuthority):
     """