Move DhcpServer to NetworkStack app

Test: atest FrameworksNetTests && atest NetworkStackTests
Bug: b/112869080

Change-Id: I96c40e63e9ceb37b67705bdd4d120307e114715b

1 files changed, 42 insertions, 0 deletions

diff --git a/src/com/android/server/util/PermissionUtil.java b/src/com/android/server/util/PermissionUtil.java
new file mode 100644
index 0000000..733f873
--- /dev/null
+++ b/src/com/android/server/util/PermissionUtil.java
@@ -0,0 +1,42 @@
+/*
+ * 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.util;
+
+import static android.os.Binder.getCallingUid;
+
+import android.os.Process;
+
+/**
+ * Utility class to check calling permissions on the network stack.
+ */
+public final class PermissionUtil {
+
+    /**
+     * Check that the caller is allowed to communicate with the network stack.
+     * @throws SecurityException The caller is not allowed to communicate with the network stack.
+     */
+    public static void checkNetworkStackCallingPermission() {
+        // 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());
+        }
+    }
+
+    private PermissionUtil() {
+        throw new UnsupportedOperationException("This class is not to be instantiated");
+    }
+}