dns: add basic functional "make test" case

Type: test
Signed-off-by: Dave Barach <dave@barachs.net>
Change-Id: I88e93b510d8d4f7b59f3e630539dc7e0264afa47

2 files changed, 114 insertions, 0 deletions

diff --git a/src/vnet/dns/dns.c b/src/vnet/dns/dns.c
index eac95450485..304aa1868fe 100644
--- a/src/vnet/dns/dns.c
+++ b/src/vnet/dns/dns.c
@@ -821,6 +821,10 @@ vnet_dns_resolve_name (dns_main_t * dm, u8 * name, dns_pending_request_t * t,
   /* In case we can't actually answer the question right now... */
   *retp = 0;
 
+  /* binary API caller might forget to set the name. Guess how we know. */
+  if (name[0] == 0)
+    return VNET_API_ERROR_INVALID_VALUE;
+
   dns_cache_lock (dm);
 search_again:
   p = hash_get_mem (dm->cache_entry_by_name, name);
diff --git a/test/test_dns.py b/test/test_dns.py
new file mode 100644
index 00000000000..307e73c983a
--- /dev/null
+++ b/test/test_dns.py
@@ -0,0 +1,110 @@
+#!/usr/bin/env python
+
+import unittest
+
+from framework import VppTestCase, VppTestRunner
+from vpp_ip_route import VppIpTable, VppIpRoute, VppRoutePath
+from vpp_ip import VppIpPrefix
+from ipaddress import *
+
+import scapy.compat
+from scapy.contrib.mpls import MPLS
+from scapy.layers.inet import IP, UDP, TCP, ICMP, icmptypes, icmpcodes
+from scapy.layers.l2 import Ether
+from scapy.packet import Raw
+from scapy.layers.dns import DNSRR, DNS, DNSQR
+
+
+class TestDns(VppTestCase):
+    """ Dns Test Cases """
+
+    @classmethod
+    def setUpClass(cls):
+        super(TestDns, cls).setUpClass()
+
+    @classmethod
+    def tearDownClass(cls):
+        super(TestDns, cls).tearDownClass()
+
+    def setUp(self):
+        super(TestDns, self).setUp()
+
+        self.create_pg_interfaces(range(1))
+
+        for i in self.pg_interfaces:
+            i.admin_up()
+            i.config_ip4()
+            i.resolve_arp()
+
+    def tearDown(self):
+        super(TestDns, self).tearDown()
+
+    def create_stream(self, src_if):
+        """Create input packet stream for defined interface.
+
+        :param VppInterface src_if: Interface to create packet stream for.
+        """
+        good_request = (Ether(dst=src_if.local_mac, src=src_if.remote_mac) /
+                        IP(src=src_if.remote_ip4) /
+                        UDP(sport=1234, dport=53) /
+                        DNS(rd=1, qd=DNSQR(qname="bozo.clown.org")))
+
+        bad_request = (Ether(dst=src_if.local_mac, src=src_if.remote_mac) /
+                       IP(src=src_if.remote_ip4) /
+                       UDP(sport=1234, dport=53) /
+                       DNS(rd=1, qd=DNSQR(qname="no.clown.org")))
+        pkts = [good_request, bad_request]
+        return pkts
+
+    def verify_capture(self, dst_if, capture):
+        """Verify captured input packet stream for defined interface.
+
+        :param VppInterface dst_if: Interface to verify captured packet stream
+            for.
+        :param list capture: Captured packet stream.
+        """
+        self.logger.info("Verifying capture on interface %s" % dst_if.name)
+        for packet in capture:
+            dns = packet[DNS]
+            self.assertEqual(dns.an[0].rdata, '1.2.3.4')
+
+    def test_dns_unittest(self):
+        """ DNS Name Resolver Basic Functional Test """
+
+        # Set up an upstream name resolver. We won't actually go there
+        self.vapi.dns_name_server_add_del(
+            is_ip6=0, is_add=1, server_address=IPv4Address(u'8.8.8.8').packed)
+
+        # Enable name resolution
+        self.vapi.dns_enable_disable(enable=1)
+
+        # Manually add a static dns cache entry
+        self.logger.info(self.vapi.cli("dns cache add bozo.clown.org 1.2.3.4"))
+
+        # Test the binary API
+        rv = self.vapi.dns_resolve_name(name='bozo.clown.org')
+        self.assertEqual(rv.ip4_address, IPv4Address(u'1.2.3.4').packed)
+
+        # Configure 127.0.0.1/8 on the pg interface
+        self.vapi.sw_interface_add_del_address(
+            sw_if_index=self.pg0.sw_if_index,
+            prefix=VppIpPrefix("127.0.0.1", 8).encode())
+
+        # Send a couple of DNS request packets, one for bozo.clown.org
+        # and one for no.clown.org which won't resolve
+
+        pkts = self.create_stream(self.pg0)
+        self.pg0.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+
+        self.pg_start()
+        pkts = self.pg0.get_capture(1)
+        self.verify_capture(self.pg0, pkts)
+
+        # Make sure that the cache contents are correct
+        str = self.vapi.cli("show dns cache verbose")
+        self.assertIn('1.2.3.4', str)
+        self.assertIn('[P] no.clown.org:', str)
+
+if __name__ == '__main__':
+    unittest.main(testRunner=VppTestRunner)