diff --git a/core/java/android/net/ConnectivityManager.java b/core/java/android/net/ConnectivityManager.java
index 436b4a1..abc00fe 100644
--- a/core/java/android/net/ConnectivityManager.java
+++ b/core/java/android/net/ConnectivityManager.java
@@ -2051,6 +2051,16 @@
         return (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
     }
 
+    /** @hide */
+    public NetworkRequest getDefaultRequest() {
+        try {
+            // This is not racy as the default request is final in ConnectivityService.
+            return mService.getDefaultRequest();
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+    }
+
     /* TODO: These permissions checks don't belong in client-side code. Move them to
      * services.jar, possibly in com.android.server.net. */
 
diff --git a/core/java/android/net/IConnectivityManager.aidl b/core/java/android/net/IConnectivityManager.aidl
index e7d441d..da5d96e 100644
--- a/core/java/android/net/IConnectivityManager.aidl
+++ b/core/java/android/net/IConnectivityManager.aidl
@@ -167,6 +167,8 @@
 
     int getMultipathPreference(in Network Network);
 
+    NetworkRequest getDefaultRequest();
+
     int getRestoreDefaultNetworkDelay(int networkType);
 
     boolean addVpnAddress(String address, int prefixLength);
diff --git a/core/java/android/net/INetworkMonitor.aidl b/core/java/android/net/INetworkMonitor.aidl
new file mode 100644
index 0000000..41f969a
--- /dev/null
+++ b/core/java/android/net/INetworkMonitor.aidl
@@ -0,0 +1,45 @@
+/**
+ * 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 perNmissions and
+ * limitations under the License.
+ */
+package android.net;
+
+import android.net.PrivateDnsConfigParcel;
+
+/** @hide */
+oneway interface INetworkMonitor {
+    // After a network has been tested this result can be sent with EVENT_NETWORK_TESTED.
+    // The network should be used as a default internet connection.  It was found to be:
+    // 1. a functioning network providing internet access, or
+    // 2. a captive portal and the user decided to use it as is.
+    const int NETWORK_TEST_RESULT_VALID = 0;
+
+    // After a network has been tested this result can be sent with EVENT_NETWORK_TESTED.
+    // The network should not be used as a default internet connection.  It was found to be:
+    // 1. a captive portal and the user is prompted to sign-in, or
+    // 2. a captive portal and the user did not want to use it, or
+    // 3. a broken network (e.g. DNS failed, connect failed, HTTP request failed).
+    const int NETWORK_TEST_RESULT_INVALID = 1;
+
+    void start();
+    void launchCaptivePortalApp();
+    void forceReevaluation(int uid);
+    void notifyPrivateDnsChanged(in PrivateDnsConfigParcel config);
+    void notifyDnsResponse(int returnCode);
+    void notifySystemReady();
+    void notifyNetworkConnected();
+    void notifyNetworkDisconnected();
+    void notifyLinkPropertiesChanged();
+    void notifyNetworkCapabilitiesChanged();
+}
\ No newline at end of file
diff --git a/core/java/android/net/INetworkMonitorCallbacks.aidl b/core/java/android/net/INetworkMonitorCallbacks.aidl
new file mode 100644
index 0000000..0bc2575
--- /dev/null
+++ b/core/java/android/net/INetworkMonitorCallbacks.aidl
@@ -0,0 +1,29 @@
+/*
+ * 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 android.net;
+
+import android.net.INetworkMonitor;
+import android.net.PrivateDnsConfigParcel;
+
+/** @hide */
+oneway interface INetworkMonitorCallbacks {
+    void onNetworkMonitorCreated(in INetworkMonitor networkMonitor);
+    void notifyNetworkTested(int testResult, @nullable String redirectUrl);
+    void notifyPrivateDnsConfigResolved(in PrivateDnsConfigParcel config);
+    void showProvisioningNotification(String action);
+    void hideProvisioningNotification();
+}
\ No newline at end of file
diff --git a/core/java/android/net/INetworkStackConnector.aidl b/core/java/android/net/INetworkStackConnector.aidl
index be0dc07..2df8ab7 100644
--- a/core/java/android/net/INetworkStackConnector.aidl
+++ b/core/java/android/net/INetworkStackConnector.aidl
@@ -15,6 +15,7 @@
  */
 package android.net;
 
+import android.net.INetworkMonitorCallbacks;
 import android.net.dhcp.DhcpServingParamsParcel;
 import android.net.dhcp.IDhcpServerCallbacks;
 
@@ -22,4 +23,5 @@
 oneway interface INetworkStackConnector {
     void makeDhcpServer(in String ifName, in DhcpServingParamsParcel params,
         in IDhcpServerCallbacks cb);
+    void makeNetworkMonitor(int netId, String name, in INetworkMonitorCallbacks cb);
 }
\ No newline at end of file
diff --git a/core/java/android/net/NetworkStack.java b/core/java/android/net/NetworkStack.java
index d4a0ec63..2eac6de 100644
--- a/core/java/android/net/NetworkStack.java
+++ b/core/java/android/net/NetworkStack.java
@@ -48,14 +48,16 @@
 public class NetworkStack {
     private static final String TAG = NetworkStack.class.getSimpleName();
 
+    public static final String NETWORKSTACK_PACKAGE_NAME = "com.android.mainline.networkstack";
+
     @NonNull
     @GuardedBy("mPendingNetStackRequests")
-    private final ArrayList<NetworkStackRequest> mPendingNetStackRequests = new ArrayList<>();
+    private final ArrayList<NetworkStackCallback> mPendingNetStackRequests = new ArrayList<>();
     @Nullable
     @GuardedBy("mPendingNetStackRequests")
     private INetworkStackConnector mConnector;
 
-    private interface NetworkStackRequest {
+    private interface NetworkStackCallback {
         void onNetworkStackConnected(INetworkStackConnector connector);
     }
 
@@ -77,6 +79,21 @@
         });
     }
 
+    /**
+     * Create a NetworkMonitor.
+     *
+     * <p>The INetworkMonitor will be returned asynchronously through the provided callbacks.
+     */
+    public void makeNetworkMonitor(Network network, String name, INetworkMonitorCallbacks cb) {
+        requestConnector(connector -> {
+            try {
+                connector.makeNetworkMonitor(network.netId, name, cb);
+            } catch (RemoteException e) {
+                e.rethrowFromSystemServer();
+            }
+        });
+    }
+
     private class NetworkStackConnection implements ServiceConnection {
         @Override
         public void onServiceConnected(ComponentName name, IBinder service) {
@@ -96,14 +113,14 @@
         ServiceManager.addService(Context.NETWORK_STACK_SERVICE, service, false /* allowIsolated */,
                 DUMP_FLAG_PRIORITY_HIGH | DUMP_FLAG_PRIORITY_NORMAL);
 
-        final ArrayList<NetworkStackRequest> requests;
+        final ArrayList<NetworkStackCallback> requests;
         synchronized (mPendingNetStackRequests) {
             requests = new ArrayList<>(mPendingNetStackRequests);
             mPendingNetStackRequests.clear();
             mConnector = connector;
         }
 
-        for (NetworkStackRequest r : requests) {
+        for (NetworkStackCallback r : requests) {
             r.onNetworkStackConnected(connector);
         }
     }
@@ -124,7 +141,8 @@
                     "com.android.server.NetworkStackService",
                     true /* initialize */,
                     context.getClassLoader());
-            connector = (IBinder) service.getMethod("makeConnector").invoke(null);
+            connector = (IBinder) service.getMethod("makeConnector", Context.class)
+                    .invoke(null, context);
         } catch (NoSuchMethodException | IllegalAccessException | InvocationTargetException e) {
             Slog.wtf(TAG, "Could not create network stack connector from NetworkStackService");
             // TODO: crash/reboot system here ?
@@ -153,7 +171,7 @@
     }
 
     // TODO: use this method to obtain the connector when implementing network stack operations
-    private void requestConnector(@NonNull NetworkStackRequest request) {
+    private void requestConnector(@NonNull NetworkStackCallback request) {
         // TODO: PID check.
         if (Binder.getCallingUid() != Process.SYSTEM_UID) {
             // Don't even attempt to obtain the connector and give a nice error message
diff --git a/core/java/android/net/PrivateDnsConfigParcel.aidl b/core/java/android/net/PrivateDnsConfigParcel.aidl
new file mode 100644
index 0000000..b52fce6
--- /dev/null
+++ b/core/java/android/net/PrivateDnsConfigParcel.aidl
@@ -0,0 +1,22 @@
+/*
+ * 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 android.net;
+
+parcelable PrivateDnsConfigParcel {
+    String hostname;
+    String[] ips;
+}