Add simple NetdService util class

am: c1bc0be161

Change-Id: I67d1ecda70efca7b47d6ebfb79c7da941d51965e

services/core/java/com/android/server/connectivity/tethering/IPv6TetheringInterfaceServices.java

@@ -25,6 +25,7 @@ import android.net.NetworkState;
 import android.net.RouteInfo;
 import android.net.ip.RouterAdvertisementDaemon;
 import android.net.ip.RouterAdvertisementDaemon.RaParams;
+import android.net.util.NetdService;
 import android.os.INetworkManagementService;
 import android.os.ServiceSpecificException;
 import android.os.RemoteException;
@@ -193,7 +194,7 @@ class IPv6TetheringInterfaceServices {
 
     private void configureLocalDns(
             HashSet<Inet6Address> deprecatedDnses, HashSet<Inet6Address> newDnses) {
-        INetd netd = getNetdServiceOrNull();
+        final INetd netd = NetdService.getInstance();
         if (netd == null) {
             if (newDnses != null) newDnses.clear();
             Log.e(TAG, "No netd service instance available; not setting local IPv6 addresses");
@@ -265,18 +266,6 @@ class IPv6TetheringInterfaceServices {
         return localRoutes;
     }
 
-    private INetd getNetdServiceOrNull() {
-        if (mNMService != null) {
-            try {
-                return mNMService.getNetdService();
-            } catch (RemoteException ignored) {
-                // This blocks until netd can be reached, but it can return
-                // null during a netd crash.
-            }
-        }
-        return null;
-    }
-
     // Given a prefix like 2001:db8::/64 return 2001:db8::1.
     private static Inet6Address getLocalDnsIpFor(IpPrefix localPrefix) {
         final byte[] dnsBytes = localPrefix.getRawAddress();

services/net/Android.mk

@@ -5,6 +5,10 @@ include $(CLEAR_VARS)
 LOCAL_MODULE := services.net
 
 LOCAL_SRC_FILES += \
-    $(call all-java-files-under,java)
+    $(call all-java-files-under,java)  \
+    ../../../../system/netd/server/binder/android/net/INetd.aidl
+
+LOCAL_AIDL_INCLUDES += \
+    system/netd/server/binder
 
 include $(BUILD_STATIC_JAVA_LIBRARY)

services/net/java/android/net/util/NetdService.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net.util;
+
+import android.net.INetd;
+import android.os.ServiceManager;
+import android.util.Log;
+
+
+/**
+ * @hide
+ */
+public class NetdService {
+    private static final String TAG = NetdService.class.getSimpleName();
+    private static final String NETD_SERVICE_NAME = "netd";
+
+    /**
+     * It is the caller's responsibility to check for a null return value
+     * and to handle RemoteException errors from invocations on the returned
+     * interface if, for example, netd dies and is restarted.
+     *
+     * @return an INetd instance or null.
+     */
+    public static INetd getInstance() {
+        final INetd netdInstance = INetd.Stub.asInterface(
+                ServiceManager.getService(NETD_SERVICE_NAME));
+        if (netdInstance == null) {
+            Log.w(TAG, "WARNING: returning null INetd instance.");
+        }
+        return netdInstance;
+    }
+}