Add TXT records in .other pseudo-domain to reveal the other_action value

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

diff --git a/invirt-dns b/invirt-dns
index 672d1f4..2b920bd 100755 (executable)
--- a/invirt-dns
+++ b/invirt-dns
@@ -4,12 +4,14 @@ from twisted.names import server
 from twisted.names import dns
 from twisted.names import common
 from twisted.names import authority
+from twisted.names import resolve
 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
+from invirt.database import NIC
 import psycopg2
 import sqlalchemy
 import time
@@ -45,7 +47,7 @@ class DatabaseAuthority(common.ResolverBase):
         for i in range(3):
             try:
                 value = self._lookup_unsafe(name, cls, type, timeout = None)
-            except (psycopg2.OperationalError, sqlalchemy.exceptions.SQLError):
+            except (psycopg2.OperationalError, sqlalchemy.exceptions.DBAPIError):
                 if i == 2:
                     raise
                 print "Reloading database"
@@ -93,10 +95,12 @@ class DatabaseAuthority(common.ResolverBase):
         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()
+                value = invirt.database.NIC.query.filter((NIC.ip == ip) | (NIC.other_ip == ip)).first()
                 if value and value.hostname:
                     hostname = value.hostname
                     if '.' not in hostname:
+                        if ip == value.other_ip:
+                            hostname = hostname + ".other"
                         hostname = hostname + "." + config.dns.domains[0]
                     record = dns.Record_PTR(hostname, ttl)
                     results.append(dns.RRHeader(name, dns.PTR, dns.IN,
@@ -108,7 +112,7 @@ class DatabaseAuthority(common.ResolverBase):
                                             ttl, self.soa, auth=True))
             # FIXME: Should only return success with no records if the name actually exists
 
-        elif name == domain or name == '.'+domain:
+        elif name == domain or name == '.'+domain or name == 'other.'+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,
@@ -123,13 +127,25 @@ class DatabaseAuthority(common.ResolverBase):
 
         else:
             host = name[:-len(domain)-1]
+            other = False
+            if host.endswith(".other"):
+                host = host[:-len(".other")]
+                other = True
             value = invirt.database.NIC.query.filter_by(hostname=host).first()
             if value:
-                ip = value.ip
+                if other:
+                    ip = value.other_ip
+                    action = value.other_action
+                else:
+                    ip = value.ip
             else:
-                value = invirt.database.Machine.query().filter_by(name=host).first()
+                value = invirt.database.Machine.query.filter_by(name=host).first()
                 if value:
-                    ip = value.nics[0].ip
+                    if other:
+                        ip = value.nics[0].other_ip
+                        action = value.nics[0].other_action
+                    else:
+                        ip = value.nics[0].ip
                 else:
                     return defer.fail(failure.Failure(dns.AuthoritativeDomainError(name)))
             if ip is None:
@@ -141,6 +157,10 @@ class DatabaseAuthority(common.ResolverBase):
             elif type == dns.SOA:
                 results.append(dns.RRHeader(domain, dns.SOA, dns.IN,
                                             ttl, self.soa, auth=True))
+            elif other and type == dns.TXT:
+                record = dns.Record_TXT(action if action else '', ttl=ttl)
+                results.append(dns.RRHeader(name, dns.TXT, dns.IN,
+                                            ttl, record, auth=True))
 
         if len(results) == 0:
             authority = []
@@ -207,19 +227,27 @@ class DelegatingQuotingBindAuthority(authority.BindAuthority):
             name = name[name.find('.') + 1 :]
             deferredResult = authority.BindAuthority._lookup(self, name, cls,
                                                              dns.NS, timeout)
-        # If we found somewhere to delegate the query to, our _lookup()
-        # for the NS record resulted in it being in the 'results' section.
-        # We need to instead return that information in the 'authority'
-        # section to delegate, and return an empty 'results' section
-        # (because we didn't find the name we were asked about).  We
-        # leave the 'additional' section as we received it because it
-        # may contain A records for the DNS server we're delegating to.
-        if maybeDelegate and not isinstance(deferredResult.result,
-                                            failure.Failure):
-            (nsResults, nsAuthority, nsAdditional) = deferredResult.result
-            deferredResult = defer.succeed(([], nsResults, nsAdditional))
         return deferredResult
 
+class TypeLenientResolverChain(resolve.ResolverChain):
+    """
+    This is a ResolverChain which is more lenient in its handling of
+    queries requesting unimplemented record types.
+    """
+
+    def query(self, query, timeout = None):
+        try:
+            return self.typeToMethod[query.type](str(query.name), timeout)
+        except KeyError, e:
+            # We don't support the requested record type.  Twisted would
+            # have us return SERVFAIL.  Instead, we'll check whether the
+            # name exists in our zone at all and return NXDOMAIN or an empty
+            # result set with NOERROR as appropriate.
+            deferredResult = self.lookupAllRecords(str(query.name), timeout)
+            if isinstance(deferredResult.result, failure.Failure):
+                return deferredResult
+            return defer.succeed(([], [], []))
+
 if '__main__' == __name__:
     resolvers = []
     try:
@@ -240,7 +268,8 @@ if '__main__' == __name__:
     resolvers.append(DatabaseAuthority())
 
     verbosity = 0
-    f = server.DNSServerFactory(authorities=resolvers, verbose=verbosity)
+    f = server.DNSServerFactory(verbose=verbosity)
+    f.resolver = TypeLenientResolverChain(resolvers)
     p = dns.DNSDatagramProtocol(f)
     f.noisy = p.noisy = verbosity