s4 dns: Add a first test case

source4/scripting/python/samba/tests/dns.py

@@ -0,0 +1,117 @@
+#!/usr/bin/env python
+
+# Unix SMB/CIFS implementation.
+# Copyright (C) Kai Blin  <kai@samba.org> 2011
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+import os
+import sys
+import struct
+import random
+from samba import socket
+import samba.ndr as ndr
+import samba.dcerpc.dns as dns
+from samba.tests import TestCase
+
+class DNSTest(TestCase):
+
+    def assert_dns_rcode_equals(self, packet, rcode):
+        "Helper function to check return code"
+        p_errcode = packet.operation & 0x000F
+        self.assertEquals(p_errcode, rcode, "Expected RCODE %s, got %s" % \
+                            (rcode, p_errcode))
+
+    def assert_dns_opcode_equals(self, packet, opcode):
+        "Helper function to check opcode"
+        p_opcode = packet.operation & 0x7800
+        self.assertEquals(p_opcode, opcode, "Expected OPCODE %s, got %s" % \
+                            (opcode, p_opcode))
+
+    def make_name_packet(self, opcode, qid=None):
+        "Helper creating a dns.name_packet"
+        p = dns.name_packet()
+        if qid is None:
+            p.id = random.randint(0x0, 0xffff)
+        p.operation = opcode
+        p.questions = []
+        return p
+
+    def finish_name_packet(self, packet, questions):
+        "Helper to finalize a dns.name_packet"
+        packet.qdcount = len(questions)
+        packet.questions = questions
+
+    def make_name_question(self, name, qtype, qclass):
+        "Helper creating a dns.name_question"
+        q = dns.name_question()
+        q.name = name
+        q.question_type = qtype
+        q.question_class = qclass
+        return q
+
+    def get_dns_domain(self):
+        "Helper to get dns domain"
+        return os.getenv('REALM', 'example.com').lower()
+
+    def test_one_a_query(self):
+        "create a query packet containing one query record"
+        p = self.make_name_packet(dns.DNS_OPCODE_QUERY)
+        questions = []
+
+        name = "%s.%s" % (os.getenv('DC_SERVER'), self.get_dns_domain())
+        q = self.make_name_question(name, dns.DNS_QTYPE_A, dns.DNS_QCLASS_IN)
+        print "asking for ", q.name
+        questions.append(q)
+
+        self.finish_name_packet(p, questions)
+        response = self.dns_transaction_udp(p)
+        self.assert_dns_rcode_equals(response, dns.DNS_RCODE_OK)
+        self.assert_dns_opcode_equals(response, dns.DNS_OPCODE_QUERY)
+
+    def test_two_queries(self):
+        "create a query packet containing two query records"
+        p = self.make_name_packet(dns.DNS_OPCODE_QUERY)
+        questions = []
+
+        name = "%s.%s" % (os.getenv('DC_SERVER'), self.get_dns_domain())
+        q = self.make_name_question(name, dns.DNS_QTYPE_A, dns.DNS_QCLASS_IN)
+        questions.append(q)
+
+        name = "%s.%s" % ('bogusname', self.get_dns_domain())
+        q = self.make_name_question(name, dns.DNS_QTYPE_A, dns.DNS_QCLASS_IN)
+        questions.append(q)
+
+        self.finish_name_packet(p, questions)
+        response = self.dns_transaction_udp(p)
+        self.assert_dns_rcode_equals(response, dns.DNS_RCODE_FORMERR)
+
+    def dns_transaction_udp(self, packet, host=os.getenv('DC_SERVER_IP')):
+        "send a DNS query and read the reply"
+        s = None
+        try:
+            send_packet = ndr.ndr_pack(packet)
+            s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, 0)
+            s.connect((host, 53))
+            s.send(send_packet, 0)
+            recv_packet = s.recv(2048, 0)
+            return ndr.ndr_unpack(dns.name_packet, recv_packet)
+        finally:
+            if s is not None:
+                s.close()
+
+if __name__ == "__main__":
+    import unittest
+    unittest.main()