Set static preference field only if local preference field is

initialized

In case of service instance, VMI would have VMI_property field
set, but the local preference value would not be assigned
in such cases also agent was not running mastership algorithm for
active path selection based on traffic.Set static preference only
if local preference is greater than 0, such that if AAP
address is assigned to service interface it works fine.
Test case for same.
Closes-bug:#1435689

Change-Id: If642ae574306cc6339ef03cb6783acb720092ac7

src/vnsw/agent/oper/test/test_aap.cc

@@ -528,6 +528,24 @@ TEST_F(TestAap, StaticMachine_11) {
     EXPECT_TRUE(path->path_preference().static_preference() == false);
 }
 
+//Verify that static preference is not populated
+//when preference value is set to 0
+TEST_F(TestAap, StateMachine_12) {
+    AddStaticPreference("intf1", 1, 0);
+    Ip4Address ip = Ip4Address::from_string("1.1.1.1");
+    EXPECT_TRUE(RouteFind("vrf1", ip, 32));
+
+    InetUnicastRouteEntry *rt =
+        RouteGet("vrf1", ip, 32);
+    const AgentPath *path = rt->GetActivePath();
+    EXPECT_TRUE(path->path_preference().sequence() == 0);
+    EXPECT_TRUE(path->path_preference().preference() == PathPreference::LOW);
+    EXPECT_TRUE(path->path_preference().ecmp() == false);
+    EXPECT_TRUE(path->path_preference().wait_for_traffic() == true);
+    EXPECT_TRUE(path->path_preference().static_preference() == false);
+}
+
+
 int main(int argc, char *argv[]) {
     GETUSERARGS();
     client = TestInit(init_file, ksync_init);

src/vnsw/agent/oper/vm_interface.cc

@@ -634,9 +634,15 @@ static void BuildAttributes(Agent *agent, IFMapNode *node,
     //Extract the local preference
     if (cfg->IsPropertySet(VirtualMachineInterface::PROPERTIES)) {
         autogen::VirtualMachineInterfacePropertiesType prop = cfg->properties();
-        data->local_preference_ = VmInterface::LOW;
-        if (prop.local_preference == VmInterface::HIGH) {
-            data->local_preference_ = VmInterface::HIGH;
+        //Service instance also would have VirtualMachineInterface
+        //properties field set, pick up local preference
+        //value only when it has been initialized to proper
+        //value, if its 0, ignore the local preference
+        if (prop.local_preference) {
+            data->local_preference_ = VmInterface::LOW;
+            if (prop.local_preference == VmInterface::HIGH) {
+                data->local_preference_ = VmInterface::HIGH;
+            }
         }
     }