Skeleton for IVmTethering service with flag guarding

This reverts commit f9676878292a49caa03e5270c3be2769b029db60.

Bug: 340376953
Test: adb shell /apex/com.android.virt/bin/vm run-microdroid --network-supported

Change-Id: I9c859dd43e7ba7c852a71afce8f36ca10477ad24
diff --git a/java/jni/Android.bp b/java/jni/Android.bp
index 4a569d4..d9b1880 100644
--- a/java/jni/Android.bp
+++ b/java/jni/Android.bp
@@ -20,6 +20,20 @@
 }
 
 cc_library_shared {
+    name: "libvirtualizationsystemservice_jni",
+    defaults: ["avf_build_flags_cc"],
+    srcs: [
+        "com_android_system_virtualmachine_VirtualizationSystemService.cpp",
+    ],
+    apex_available: ["com.android.virt"],
+    shared_libs: [
+        "liblog",
+        "libnativehelper",
+    ],
+    static_libs: ["libavf_cc_flags"],
+}
+
+cc_library_shared {
     name: "libvirtualmachine_jni",
     defaults: ["avf_build_flags_cc"],
     srcs: [
diff --git a/java/jni/com_android_system_virtualmachine_VirtualizationSystemService.cpp b/java/jni/com_android_system_virtualmachine_VirtualizationSystemService.cpp
new file mode 100644
index 0000000..a15e7a7
--- /dev/null
+++ b/java/jni/com_android_system_virtualmachine_VirtualizationSystemService.cpp
@@ -0,0 +1,27 @@
+/*
+ * Copyright 2024 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.
+ */
+
+#define LOG_TAG "VirtualizationSystemService"
+
+#include <android/avf_cc_flags.h>
+#include <jni.h>
+#include <log/log.h>
+
+extern "C" JNIEXPORT jboolean JNICALL
+Java_com_android_system_virtualmachine_VirtualizationSystemService_nativeIsNetworkFlagEnabled(
+        [[maybe_unused]] JNIEnv* env, [[maybe_unused]] jobject obj) {
+    return android::virtualization::IsNetworkFlagEnabled();
+}
diff --git a/java/service/Android.bp b/java/service/Android.bp
index 8bac7be..814445c 100644
--- a/java/service/Android.bp
+++ b/java/service/Android.bp
@@ -31,6 +31,7 @@
     ],
     static_libs: [
         "android.system.virtualizationmaintenance-java",
+        "android.system.vmtethering-java",
     ],
     sdk_version: "core_platform",
     apex_available: ["com.android.virt"],
diff --git a/java/service/src/com/android/system/virtualmachine/VirtualizationSystemService.java b/java/service/src/com/android/system/virtualmachine/VirtualizationSystemService.java
index 2461755..970f780 100644
--- a/java/service/src/com/android/system/virtualmachine/VirtualizationSystemService.java
+++ b/java/service/src/com/android/system/virtualmachine/VirtualizationSystemService.java
@@ -26,6 +26,7 @@
 import android.os.ServiceManager;
 import android.os.UserHandle;
 import android.system.virtualizationmaintenance.IVirtualizationMaintenance;
+import android.system.vmtethering.IVmTethering;
 import android.util.Log;
 
 import com.android.internal.os.BackgroundThread;
@@ -39,18 +40,35 @@
  * storing secrets for apps or users that no longer exist.
  */
 public class VirtualizationSystemService extends SystemService {
+    static {
+        System.loadLibrary("virtualizationsystemservice_jni");
+    }
+
     private static final String TAG = VirtualizationSystemService.class.getName();
-    private static final String SERVICE_NAME = "android.system.virtualizationmaintenance";
+    private static final String MAINTENANCE_SERVICE_NAME =
+            "android.system.virtualizationmaintenance";
     private Handler mHandler;
+    private final TetheringService mTetheringService;
+
+    /*
+     * Retrieve boolean value whether RELEASE_AVF_ENABLE_NETWORK build flag is enabled or not.
+     */
+    static native boolean nativeIsNetworkFlagEnabled();
 
     public VirtualizationSystemService(Context context) {
         super(context);
+        if (nativeIsNetworkFlagEnabled()) {
+            mTetheringService = new TetheringService();
+        } else {
+            mTetheringService = null;
+        }
     }
 
     @Override
     public void onStart() {
-        // Nothing needed here - we don't expose any binder service. The binder service we use is
-        // exposed as a lazy service by the virtualizationservice native binary.
+        if (mTetheringService != null) {
+            publishBinderService(IVmTethering.DESCRIPTOR, mTetheringService);
+        }
     }
 
     @Override
@@ -82,11 +100,11 @@
     }
 
     static IVirtualizationMaintenance connectToMaintenanceService() {
-        IBinder binder = ServiceManager.waitForService(SERVICE_NAME);
+        IBinder binder = ServiceManager.waitForService(MAINTENANCE_SERVICE_NAME);
         IVirtualizationMaintenance maintenance =
                 IVirtualizationMaintenance.Stub.asInterface(binder);
         if (maintenance == null) {
-            throw new IllegalStateException("Failed to connect to " + SERVICE_NAME);
+            throw new IllegalStateException("Failed to connect to " + MAINTENANCE_SERVICE_NAME);
         }
         return maintenance;
     }
@@ -136,4 +154,11 @@
             }
         }
     }
+
+    private static final class TetheringService extends IVmTethering.Stub {
+        @Override
+        public void enableVmTethering() throws UnsupportedOperationException {
+            throw new UnsupportedOperationException("VM tethering is not supported yet");
+        }
+    }
 }