refactor DNS logic; fix some bugs in reverse-resolution

[invirt/packages/invirt-dns.git] / invirt-dns

diff --git a/invirt-dns b/invirt-dns
index b2a9ac6..1744ac8 100755 (executable)
--- a/invirt-dns
+++ b/invirt-dns
@@ -7,6 +7,7 @@ from twisted.names import authority
 from twisted.internet import defer
 from twisted.python import failure
 
+from invirt.common import InvirtConfigError
 from invirt.config import structs as config
 import invirt.database
 import psycopg2
@@ -62,14 +63,17 @@ class DatabaseAuthority(common.ResolverBase):
         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.)
+            # Look for the longest-matching domain.
             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)))
+                if name.endswith('.in-addr.arpa'):
+                    # Act authoritative for the IP address for reverse resolution requests
+                    best_domain = name
+                else:
+                    return defer.fail(failure.Failure(dns.DomainError(name)))
             domain = best_domain
         results = []
         authority = []
@@ -78,11 +82,27 @@ class DatabaseAuthority(common.ResolverBase):
                                       3600, self.ns, auth=True))
 
         if cls == dns.IN:
-            host = name[:-len(domain)-1]
-            if not host: # Request for the domain itself.
+            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, 
+                    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,
@@ -91,17 +111,24 @@ class DatabaseAuthority(common.ResolverBase):
                 elif type == dns.SOA:
                     results.append(dns.RRHeader(domain, dns.SOA, dns.IN,
                                                 ttl, self.soa, auth=True))
-            else: # Request for a subdomain.
-                value = invirt.database.Machine.query().filter_by(name=host).first()
-                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?
+            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)))
+
+                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, 
+                    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,
@@ -155,25 +182,29 @@ class QuotingBindAuthority(authority.BindAuthority):
         for line in lines:
             in_quote = False
             split_line = []
-            for m in string_pat.finditer(line):
+            for m in self.string_pat.finditer(line):
                 [x] = [x for x in m.groups() if x is not None]
-                split_line.append(escape_pat.sub(r'\1', x))
+                split_line.append(self.escape_pat.sub(r'\1', x))
             L.append(split_line)
         return filter(None, L)
 
 if '__main__' == __name__:
     resolvers = []
-    for zone in config.dns.zone_files:
-        for origin in config.dns.domains:
-            r = QuotingBindAuthority(zone)
-            # This sucks, but if I want a generic zone file, I have to
-            # reload the information by hand
-            r.origin = origin
-            lines = open(zone).readlines()
-            lines = r.collapseContinuations(r.stripComments(lines))
-            r.parseLines(lines)
-            
-            resolvers.append(r)
+    try:
+        for zone in config.dns.zone_files:
+            for origin in config.dns.domains:
+                r = QuotingBindAuthority(zone)
+                # This sucks, but if I want a generic zone file, I have to
+                # reload the information by hand
+                r.origin = origin
+                lines = open(zone).readlines()
+                lines = r.collapseContinuations(r.stripComments(lines))
+                r.parseLines(lines)
+                
+                resolvers.append(r)
+    except InvirtConfigError:
+        # Don't care if zone_files isn't defined
+        pass
     resolvers.append(DatabaseAuthority())
 
     verbosity = 0