server: null-check public IP before the DNS/Source NAT guard in createPublicLoadBalancerRule

createPublicLoadBalancerRule resolved ipVO only when an ipAddrId was supplied,
then at the port-53 check did (srcPortStart == DNS_PORT && ipVO.isSourceNat()).
For an elastic-LB rule created without an explicit IP (ipAddrId == null) the
system IP is allocated later, so ipVO was still null and creating a rule on
port 53 threw a NullPointerException. The ipVO == null validation only runs
further down.

Guard the check with ipVO != null so the DNS/Source NAT conflict test is
skipped when there is no IP yet; the flow then reaches the existing
can't-find-source-IP parameter error.

Adds a regression test creating a port-53 rule with a null ipAddrId
(NullPointerException before the fix).

Author: nagaboinaramgopal

server/src/main/java/com/cloud/network/lb/LoadBalancingRulesManagerImpl.java

@@ -1706,7 +1706,7 @@ public LoadBalancer createPublicLoadBalancerRule(String xId, String name, String
         IpAddress systemIp = null;
         NetworkOffering off = _entityMgr.findById(NetworkOffering.class, network.getNetworkOfferingId());
 
-        if (srcPortStart == DNS_PORT && ipVO.isSourceNat()) {
+        if (srcPortStart == DNS_PORT && ipVO != null && ipVO.isSourceNat()) {
             List<NetworkOfferingServiceMapVO> offeringServices = _networkOfferingServiceDao.listByNetworkOfferingId(network.getNetworkOfferingId());
             for (NetworkOfferingServiceMapVO serviceMapVo: offeringServices) {
                 if (serviceMapVo.getService().equals(Service.Dns.getName())) {

server/src/test/java/com/cloud/network/lb/LoadBalancingRulesManagerImplTest.java

@@ -17,10 +17,16 @@
 
 package com.cloud.network.lb;
 
+import com.cloud.exception.InvalidParameterValueException;
 import com.cloud.network.Network;
+import com.cloud.network.NetworkModel;
 import com.cloud.network.dao.LoadBalancerVO;
 import com.cloud.network.dao.NetworkDao;
 import com.cloud.network.dao.NetworkVO;
+import com.cloud.offering.NetworkOffering;
+import com.cloud.user.Account;
+import com.cloud.user.AccountManager;
+import com.cloud.utils.db.EntityManager;
 import com.cloud.utils.exception.CloudRuntimeException;
 import org.apache.cloudstack.api.ServerApiException;
 import org.apache.cloudstack.engine.orchestration.service.NetworkOrchestrationService;
@@ -48,6 +54,21 @@ public class LoadBalancingRulesManagerImplTest{
     @Mock
     NetworkOrchestrationService _networkMgr;
 
+    @Mock
+    EntityManager _entityMgr;
+
+    @Mock
+    AccountManager _accountMgr;
+
+    @Mock
+    NetworkModel _networkModel;
+
+    @Mock
+    NetworkVO networkMock;
+
+    private long accountId = 10L;
+    private long networkId = 4L;
+
     @Spy
     @InjectMocks
     LoadBalancingRulesManagerImpl lbr = new LoadBalancingRulesManagerImpl();
@@ -101,4 +122,19 @@ public void testGetLoadBalancerServiceProviderFail() {
 
         Network.Provider provider = lbr.getLoadBalancerServiceProvider(loadBalancerMock);
     }
+
+    @Test(expected = InvalidParameterValueException.class)
+    public void createPublicLoadBalancerRuleWithDnsPortAndNoIpDoesNotNpe() throws Exception {
+        long lbOwnerId = accountId;
+        long networkOfferingId = 7L;
+        when(_accountMgr.getAccount(lbOwnerId)).thenReturn(Mockito.mock(Account.class));
+        when(_networkModel.getNetwork(networkId)).thenReturn(networkMock);
+        when(networkMock.getNetworkOfferingId()).thenReturn(networkOfferingId);
+        NetworkOffering off = Mockito.mock(NetworkOffering.class);
+        when(_entityMgr.findById(NetworkOffering.class, networkOfferingId)).thenReturn(off);
+        when(off.isElasticLb()).thenReturn(false);
+
+        lbr.createPublicLoadBalancerRule("xid", "name", "desc", 53, 53, 53, 53,
+                null, "tcp", "roundrobin", networkId, lbOwnerId, false, "tcp", null, null);
+    }
 }