Reverse-resolution support in invirt-dns
[invirt/packages/invirt-dns.git] / invirt-dns
index 4193be1..d6d072e 100755 (executable)
@@ -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
@@ -92,20 +93,41 @@ class DatabaseAuthority(common.ResolverBase):
                     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?
-                    return defer.fail(failure.Failure(dns.AuthoritativeDomainError(name)))
+                if name.endswith(".in-addr.arpa"): # Reverse resolution here
+                    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)))
+                    # FIXME: Should only return success with no records if the name actually exists
+                else: # Forward resolution here
+                    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 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 = []
@@ -121,9 +143,18 @@ class QuotingBindAuthority(authority.BindAuthority):
     This will catch double quotes as marking the start or end of a
     quoted phrase, unless the double quote is escaped by a backslash
     """
-    # Grab everything up to the first whitespace character or
-    # quotation mark not proceeded by a backslash
-    whitespace_re = re.compile(r'(.*?)([\t\n\x0b\x0c\r ]+|(?<!\\)")')
+    # Match either a quoted or unquoted string literal followed by
+    # whitespace or the end of line.  This yields two groups, one of
+    # which has a match, and the other of which is None, depending on
+    # whether the string literal was quoted or unquoted; this is what
+    # necessitates the subsequent filtering out of groups that are
+    # None.
+    string_pat = \
+            re.compile(r'"((?:[^"\\]|\\.)*)"|((?:[^\\\s]|\\.)+)(?:\s+|\s*$)')
+
+    # For interpreting escapes.
+    escape_pat = re.compile(r'\\(.)')
+
     def collapseContinuations(self, lines):
         L = []
         state = 0
@@ -142,57 +173,33 @@ class QuotingBindAuthority(authority.BindAuthority):
                     L[-1] += ' ' + line
         lines = L
         L = []
+
         for line in lines:
             in_quote = False
             split_line = []
-            while len(line) > 0:
-                match = self.whitespace_re.match(line)
-                if match is None:
-                    # If there's no match, that means that there's no
-                    # whitespace in the rest of the line, so it should
-                    # be treated as a single entity, quoted or not
-                    #
-                    # This also means that a closing quote isn't
-                    # strictly necessary if the line ends the quote
-                    substr = line
-                    end = ''
-                else:
-                    substr, end = match.groups()
-                
-                if in_quote:
-                    # If we're in the middle of the quote, the string
-                    # we just grabbed belongs at the end of the
-                    # previous string
-                    #
-                    # Including the whitespace! Unless it's not
-                    # whitespace and is actually a closequote instead
-                    split_line[-1] += substr + (end if end != '"' else '')
-                else:
-                    # If we're not in the middle of a quote, than this
-                    # is the next new string
-                    split_line.append(substr)
-                
-                if end == '"':
-                    in_quote = not in_quote
-                
-                # Then strip off what we just processed
-                line = line[len(substr + end):]
+            for m in self.string_pat.finditer(line):
+                [x] = [x for x in m.groups() if x is not None]
+                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