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 4193be1..2b920bd 100755 (executable)
--- a/invirt-dns
+++ b/invirt-dns
@@ -4,11 +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 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 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.config import structs as config
 import invirt.database

+from invirt.database import NIC

 import psycopg2
 import sqlalchemy
 import time
 import psycopg2
 import sqlalchemy
 import time

@@ -44,7 +47,7 @@ class DatabaseAuthority(common.ResolverBase):
         for i in range(3):
             try:
                 value = self._lookup_unsafe(name, cls, type, timeout = None)
         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"
                 if i == 2:
                     raise
                 print "Reloading database"

@@ -62,14 +65,17 @@ class DatabaseAuthority(common.ResolverBase):
         if name in self.domains:
             domain = name
         else:
         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 == '':
             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 = []
             domain = best_domain
         results = []
         authority = []

@@ -77,53 +83,109 @@ class DatabaseAuthority(common.ResolverBase):
         authority.append(dns.RRHeader(domain, dns.NS, dns.IN,
                                       3600, self.ns, auth=True))
 
         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: # 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, 
+        # The order of logic:
+        # - What class?
+        # - What domain: in-addr.arpa, domain root, or subdomain?
+        # - What query type: A, PTR, NS, ...?
+
+        if cls != dns.IN:
+            # Hahaha.  No.
+            return defer.fail(failure.Failure(dns.AuthoritativeDomainError(name)))
+
+        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((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,

                                                 ttl, record, auth=True))
                                                 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: # 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: # IP address doesn't point to an active host

                     return defer.fail(failure.Failure(dns.AuthoritativeDomainError(name)))
                     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

 
 

-                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:
+        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,
+                                            ttl, record, auth=True))
+            elif type == dns.NS:
+                results.append(dns.RRHeader(domain, dns.NS, dns.IN,
+                                            ttl, self.ns, auth=True))

                 authority = []
                 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:
         else:

-            #Doesn't exist
-            return defer.fail(failure.Failure(dns.AuthoritativeDomainError(name)))
+            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:
+                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()
+                if value:
+                    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:
+                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))
+            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 = []
+            additional = []
+        return defer.succeed((results, authority, additional))

 
 

-class QuotingBindAuthority(authority.BindAuthority):
+class DelegatingQuotingBindAuthority(authority.BindAuthority):

     """
     """

-    A BindAuthority that (almost) deals with quoting correctly
+    A delegating BindAuthority that (almost) deals with quoting correctly

     
     This will catch double quotes as marking the start or end of a
     quoted phrase, unless the double quote is escaped by a backslash
     """
     
     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
     def collapseContinuations(self, lines):
         L = []
         state = 0

@@ -142,61 +204,72 @@ class QuotingBindAuthority(authority.BindAuthority):
                     L[-1] += ' ' + line
         lines = L
         L = []
                     L[-1] += ' ' + line
         lines = L
         L = []

+

         for line in lines:
             in_quote = False
             split_line = []
         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)
 
             L.append(split_line)
         return filter(None, L)
 

+    def _lookup(self, name, cls, type, timeout = None):
+        maybeDelegate = False
+        deferredResult = authority.BindAuthority._lookup(self, name, cls,
+                                                         type, timeout)
+        # If we didn't find an exact match for the name we were seeking,
+        # check if it's within a subdomain we're supposed to delegate to
+        # some other DNS server.
+        while (isinstance(deferredResult.result, failure.Failure)
+               and '.' in name):
+            maybeDelegate = True
+            name = name[name.find('.') + 1 :]
+            deferredResult = authority.BindAuthority._lookup(self, name, cls,
+                                                             dns.NS, timeout)
+        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 = []
 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 = DelegatingQuotingBindAuthority(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
     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
     
     p = dns.DNSDatagramProtocol(f)
     f.noisy = p.noisy = verbosity