Add NetworkStack app

The app is not started yet, and does not contain any service for now.

Test: built, booted
Bug: b/112869080
Change-Id: Id5a0fd02c891100e85d86b1040e53beec3581950

1 files changed, 74 insertions, 0 deletions

diff --git a/src/com/android/server/NetworkStackService.java b/src/com/android/server/NetworkStackService.java
new file mode 100644
index 0000000..5afaf58
--- /dev/null
+++ b/src/com/android/server/NetworkStackService.java
@@ -0,0 +1,74 @@
+/*
+ * Copyright (C) 2018 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 com.android.server;
+
+import static android.os.Binder.getCallingUid;
+
+import android.annotation.NonNull;
+import android.annotation.Nullable;
+import android.app.Service;
+import android.content.Intent;
+import android.net.INetworkStackConnector;
+import android.os.IBinder;
+import android.os.Process;
+
+import java.io.FileDescriptor;
+import java.io.PrintWriter;
+
+/**
+ * Android service used to start the network stack when bound to via an intent.
+ *
+ * <p>The service returns a binder for the system server to communicate with the network stack.
+ */
+public class NetworkStackService extends Service {
+    private static final String TAG = NetworkStackService.class.getSimpleName();
+
+    /**
+     * Create a binder connector for the system server to communicate with the network stack.
+     *
+     * <p>On platforms where the network stack runs in the system server process, this method may
+     * be called directly instead of obtaining the connector by binding to the service.
+     */
+    public static IBinder makeConnector() {
+        return new NetworkStackConnector();
+    }
+
+    @NonNull
+    @Override
+    public IBinder onBind(Intent intent) {
+        return makeConnector();
+    }
+
+    private static class NetworkStackConnector extends INetworkStackConnector.Stub {
+        // TODO: makeDhcpServer(), etc. will go here.
+
+        @Override
+        protected void dump(@NonNull FileDescriptor fd, @NonNull PrintWriter fout,
+                @Nullable String[] args) {
+            checkCaller();
+            fout.println("NetworkStack logs:");
+            // TODO: dump logs here
+        }
+    }
+
+    private static void checkCaller() {
+        // TODO: check that the calling PID is the system server.
+        if (getCallingUid() != Process.SYSTEM_UID && getCallingUid() != Process.ROOT_UID) {
+            throw new SecurityException("Invalid caller: " + getCallingUid());
+        }
+    }
+}