From 92ef52ca2031a33498b424fb204e27dfc78999d3 Mon Sep 17 00:00:00 2001
From: Felix Schumacher <felix.schumacher@internetallee.de>
Date: Fri, 16 Jan 2015 22:15:40 +0100
Subject: [PATCH] Use only configured DNS Servers

---
 .../protocol/http/control/DNSCacheManager.java     | 16 +++++++++------
 .../protocol/http/control/TestDNSCacheManager.java | 24 ++++++++++++++++++++++
 2 files changed, 34 insertions(+), 6 deletions(-)
 create mode 100644 test/src/org/apache/jmeter/protocol/http/control/TestDNSCacheManager.java

diff --git a/src/protocol/http/org/apache/jmeter/protocol/http/control/DNSCacheManager.java b/src/protocol/http/org/apache/jmeter/protocol/http/control/DNSCacheManager.java
index c3862b2..3cd31e9 100644
--- a/src/protocol/http/org/apache/jmeter/protocol/http/control/DNSCacheManager.java
+++ b/src/protocol/http/org/apache/jmeter/protocol/http/control/DNSCacheManager.java
@@ -42,7 +42,6 @@ import org.xbill.DNS.ExtendedResolver;
 import org.xbill.DNS.Lookup;
 import org.xbill.DNS.Record;
 import org.xbill.DNS.Resolver;
-import org.xbill.DNS.SimpleResolver;
 import org.xbill.DNS.TextParseException;
 import org.xbill.DNS.Type;
 
@@ -104,12 +103,17 @@ public class DNSCacheManager extends ConfigTestElement implements TestIterationL
         clone.cache = new LinkedHashMap<String, InetAddress[]>();
         CollectionProperty dnsServers = getServers();
         try {
-            clone.resolver = new ExtendedResolver();
+            String[] serverNames = new String[dnsServers.size()];
             PropertyIterator dnsServIt = dnsServers.iterator();
+            int index=0;
             while (dnsServIt.hasNext()) {
-                String dnsServer = dnsServIt.next().getStringValue();
-                ((ExtendedResolver) clone.resolver).addResolver(new SimpleResolver(dnsServer));
+                serverNames[index] = dnsServIt.next().getStringValue();
+                index++;
             }
+            clone.resolver = new ExtendedResolver(serverNames);
+            log.debug("Using DNS Resolvers: "
+                    + Arrays.asList(((ExtendedResolver) clone.resolver)
+                            .getResolvers()));
             // resolvers will be chosen via round-robin
             ((ExtendedResolver) clone.resolver).setLoadBalance(true);
         } catch (UnknownHostException uhe) {
@@ -146,13 +150,13 @@ public class DNSCacheManager extends ConfigTestElement implements TestIterationL
      */
     private InetAddress[] requestLookup(String host) throws UnknownHostException {
         InetAddress[] addresses = null;
-        if (isCustomResolver() && ((ExtendedResolver) resolver).getResolvers().length > 1) {
+        if (isCustomResolver() && ((ExtendedResolver) resolver).getResolvers().length > 0) {
             try {
                 Lookup lookup = new Lookup(host, Type.A);
                 lookup.setCache(lookupCache);
                 lookup.setResolver(resolver);
                 Record[] records = lookup.run();
-                if (records.length == 0) {
+                if (records == null || records.length == 0) {
                     throw new UnknownHostException("Failed to resolve host name: " + host);
                 }
                 addresses = new InetAddress[records.length];
diff --git a/test/src/org/apache/jmeter/protocol/http/control/TestDNSCacheManager.java b/test/src/org/apache/jmeter/protocol/http/control/TestDNSCacheManager.java
new file mode 100644
index 0000000..67a0c9f
--- /dev/null
+++ b/test/src/org/apache/jmeter/protocol/http/control/TestDNSCacheManager.java
@@ -0,0 +1,24 @@
+package org.apache.jmeter.protocol.http.control;
+
+import java.net.UnknownHostException;
+
+import org.apache.jmeter.junit.JMeterTestCase;
+import org.junit.Test;
+
+public class TestDNSCacheManager extends JMeterTestCase {
+
+    @Test
+    public void testCloneWithCustomResolverAndInvalidNameserver() throws UnknownHostException {
+        DNSCacheManager original = new DNSCacheManager();
+        original.setCustomResolver(true);
+        original.addServer("127.0.0.99");
+        DNSCacheManager clone = (DNSCacheManager) original.clone();
+        try {
+            clone.resolve("jmeter.apache.org");
+            fail();
+        } catch (UnknownHostException e) {
+            // OK
+        }
+    }
+
+}
-- 
1.9.1