Add support for TAP interfaces in TestNetworkManager.

Test: builds, boots
Change-Id: I88bfd7f37c0ba0228f8288fe92212618ce134e4f

api/test-current.txt

@@ -719,6 +719,7 @@ package android.net {
   }
 
   public class TestNetworkManager {
+    method public android.net.TestNetworkInterface createTapInterface();
     method public android.net.TestNetworkInterface createTunInterface(@NonNull android.net.LinkAddress[]);
     method public void setupTestNetwork(@NonNull String, @NonNull android.os.IBinder);
     method public void teardownTestNetwork(@NonNull android.net.Network);

core/java/android/net/ITestNetworkManager.aidl

@@ -29,6 +29,7 @@ import android.os.ParcelFileDescriptor;
 interface ITestNetworkManager
 {
     TestNetworkInterface createTunInterface(in LinkAddress[] linkAddrs);
+    TestNetworkInterface createTapInterface();
 
     void setupTestNetwork(in String iface, in IBinder binder);
 

core/java/android/net/TestNetworkManager.java

@@ -88,4 +88,21 @@ public class TestNetworkManager {
             throw e.rethrowFromSystemServer();
         }
     }
+
+    /**
+     * Create a tap interface for testing purposes
+     *
+     * @return A ParcelFileDescriptor of the underlying TAP interface. Close this to tear down the
+     *     TAP interface.
+     * @hide
+     */
+    @TestApi
+    public TestNetworkInterface createTapInterface() {
+        try {
+            return mService.createTapInterface();
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+    }
+
 }

services/core/java/com/android/server/TestNetworkService.java

@@ -60,6 +60,7 @@ class TestNetworkService extends ITestNetworkManager.Stub {
     @NonNull private static final String TAG = TestNetworkService.class.getSimpleName();
     @NonNull private static final String TEST_NETWORK_TYPE = "TEST_NETWORK";
     @NonNull private static final String TEST_TUN_PREFIX = "testtun";
+    @NonNull private static final String TEST_TAP_PREFIX = "testtap";
     @NonNull private static final AtomicInteger sTestTunIndex = new AtomicInteger();
 
     @NonNull private final Context mContext;
@@ -70,7 +71,7 @@ class TestNetworkService extends ITestNetworkManager.Stub {
     @NonNull private final Handler mHandler;
 
     // Native method stubs
-    private static native int jniCreateTun(@NonNull String iface);
+    private static native int jniCreateTunTap(boolean isTun, @NonNull String iface);
 
     @VisibleForTesting
     protected TestNetworkService(
@@ -85,23 +86,23 @@ class TestNetworkService extends ITestNetworkManager.Stub {
     }
 
     /**
-     * Create a TUN interface with the given interface name and link addresses
+     * Create a TUN or TAP interface with the given interface name and link addresses
      *
-     * <p>This method will return the FileDescriptor to the TUN interface. Close it to tear down the
-     * TUN interface.
+     * <p>This method will return the FileDescriptor to the interface. Close it to tear down the
+     * interface.
      */
-    @Override
-    public TestNetworkInterface createTunInterface(@NonNull LinkAddress[] linkAddrs) {
+    private TestNetworkInterface createInterface(boolean isTun, LinkAddress[] linkAddrs) {
         enforceTestNetworkPermissions(mContext);
 
         checkNotNull(linkAddrs, "missing linkAddrs");
 
-        String iface = TEST_TUN_PREFIX + sTestTunIndex.getAndIncrement();
+        String ifacePrefix = isTun ? TEST_TUN_PREFIX : TEST_TAP_PREFIX;
+        String iface = ifacePrefix + sTestTunIndex.getAndIncrement();
         return Binder.withCleanCallingIdentity(
                 () -> {
                     try {
                         ParcelFileDescriptor tunIntf =
-                                ParcelFileDescriptor.adoptFd(jniCreateTun(iface));
+                                ParcelFileDescriptor.adoptFd(jniCreateTunTap(isTun, iface));
                         for (LinkAddress addr : linkAddrs) {
                             mNetd.interfaceAddAddress(
                                     iface,
@@ -116,6 +117,28 @@ class TestNetworkService extends ITestNetworkManager.Stub {
                 });
     }
 
+    /**
+     * Create a TUN interface with the given interface name and link addresses
+     *
+     * <p>This method will return the FileDescriptor to the TUN interface. Close it to tear down the
+     * TUN interface.
+     */
+    @Override
+    public TestNetworkInterface createTunInterface(@NonNull LinkAddress[] linkAddrs) {
+        return createInterface(true, linkAddrs);
+    }
+
+    /**
+     * Create a TAP interface with the given interface name
+     *
+     * <p>This method will return the FileDescriptor to the TAP interface. Close it to tear down the
+     * TAP interface.
+     */
+    @Override
+    public TestNetworkInterface createTapInterface() {
+        return createInterface(false, new LinkAddress[0]);
+    }
+
     // Tracker for TestNetworkAgents
     @GuardedBy("mTestNetworkTracker")
     @NonNull

services/core/jni/com_android_server_TestNetworkService.cpp

@@ -54,12 +54,12 @@ static void throwException(JNIEnv* env, int error, const char* action, const cha
     jniThrowException(env, "java/lang/IllegalStateException", msg.c_str());
 }
 
-static int createTunInterface(JNIEnv* env, const char* iface) {
+static int createTunTapInterface(JNIEnv* env, bool isTun, const char* iface) {
     base::unique_fd tun(open("/dev/tun", O_RDWR | O_NONBLOCK));
     ifreq ifr{};
 
     // Allocate interface.
-    ifr.ifr_flags = IFF_TUN | IFF_NO_PI;
+    ifr.ifr_flags = (isTun ? IFF_TUN : IFF_TAP) | IFF_NO_PI;
     strlcpy(ifr.ifr_name, iface, IFNAMSIZ);
     if (ioctl(tun.get(), TUNSETIFF, &ifr)) {
         throwException(env, errno, "allocating", ifr.ifr_name);
@@ -80,23 +80,23 @@ static int createTunInterface(JNIEnv* env, const char* iface) {
 
 //------------------------------------------------------------------------------
 
-static jint create(JNIEnv* env, jobject /* thiz */, jstring jIface) {
+static jint create(JNIEnv* env, jobject /* thiz */, jboolean isTun, jstring jIface) {
     ScopedUtfChars iface(env, jIface);
     if (!iface.c_str()) {
         jniThrowNullPointerException(env, "iface");
         return -1;
     }
 
-    int tun = createTunInterface(env, iface.c_str());
+    int tun = createTunTapInterface(env, isTun, iface.c_str());
 
-    // Any exceptions will be thrown from the createTunInterface call
+    // Any exceptions will be thrown from the createTunTapInterface call
     return tun;
 }
 
 //------------------------------------------------------------------------------
 
 static const JNINativeMethod gMethods[] = {
-    {"jniCreateTun", "(Ljava/lang/String;)I", (void*)create},
+    {"jniCreateTunTap", "(ZLjava/lang/String;)I", (void*)create},
 };
 
 int register_android_server_TestNetworkService(JNIEnv* env) {