diff --git a/core/java/android/net/ConnectivityManager.java b/core/java/android/net/ConnectivityManager.java
index 68ac46c..99db040 100644
--- a/core/java/android/net/ConnectivityManager.java
+++ b/core/java/android/net/ConnectivityManager.java
@@ -3911,15 +3911,16 @@
      *
      * <p>This endpoint is exclusively for use by the NetworkStack and is protected by the
      * corresponding permission.
+     * @param network Network on which the captive portal was detected.
      * @param appExtras Extras to include in the app start intent.
      * @hide
      */
     @SystemApi
     @TestApi
     @RequiresPermission(NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK)
-    public void startCaptivePortalApp(Bundle appExtras) {
+    public void startCaptivePortalApp(Network network, Bundle appExtras) {
         try {
-            mService.startCaptivePortalAppInternal(appExtras);
+            mService.startCaptivePortalAppInternal(network, appExtras);
         } catch (RemoteException e) {
             throw e.rethrowFromSystemServer();
         }
diff --git a/core/java/android/net/IConnectivityManager.aidl b/core/java/android/net/IConnectivityManager.aidl
index 92a5839..83bb3a0 100644
--- a/core/java/android/net/IConnectivityManager.aidl
+++ b/core/java/android/net/IConnectivityManager.aidl
@@ -168,7 +168,7 @@
     void setAcceptUnvalidated(in Network network, boolean accept, boolean always);
     void setAvoidUnvalidated(in Network network);
     void startCaptivePortalApp(in Network network);
-    void startCaptivePortalAppInternal(in Bundle appExtras);
+    void startCaptivePortalAppInternal(in Network network, in Bundle appExtras);
 
     boolean getAvoidBadWifi();
     int getMultipathPreference(in Network Network);
diff --git a/services/core/java/com/android/server/ConnectivityService.java b/services/core/java/com/android/server/ConnectivityService.java
index af2bbfb..2cd25e4 100644
--- a/services/core/java/com/android/server/ConnectivityService.java
+++ b/services/core/java/com/android/server/ConnectivityService.java
@@ -57,8 +57,10 @@
 import android.content.IntentFilter;
 import android.content.res.Configuration;
 import android.database.ContentObserver;
+import android.net.CaptivePortal;
 import android.net.ConnectionInfo;
 import android.net.ConnectivityManager;
+import android.net.ICaptivePortal;
 import android.net.IConnectivityManager;
 import android.net.IIpConnectivityMetrics;
 import android.net.INetd;
@@ -2689,11 +2691,6 @@
                     EVENT_PROVISIONING_NOTIFICATION, PROVISIONING_NOTIFICATION_HIDE,
                     mNai.network.netId));
         }
-
-        @Override
-        public void logCaptivePortalLoginEvent(int eventId, String packageName) {
-            new MetricsLogger().action(eventId, packageName);
-        }
     }
 
     private boolean networkRequiresValidation(NetworkAgentInfo nai) {
@@ -3237,22 +3234,63 @@
     /**
      * NetworkStack endpoint to start the captive portal app. The NetworkStack needs to use this
      * endpoint as it does not have INTERACT_ACROSS_USERS_FULL itself.
+     * @param network Network on which the captive portal was detected.
      * @param appExtras Bundle to use as intent extras for the captive portal application.
      *                  Must be treated as opaque to avoid preventing the captive portal app to
      *                  update its arguments.
      */
     @Override
-    public void startCaptivePortalAppInternal(Bundle appExtras) {
+    public void startCaptivePortalAppInternal(Network network, Bundle appExtras) {
         mContext.checkCallingOrSelfPermission(NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK);
 
         final Intent appIntent = new Intent(ConnectivityManager.ACTION_CAPTIVE_PORTAL_SIGN_IN);
         appIntent.putExtras(appExtras);
+        appIntent.putExtra(ConnectivityManager.EXTRA_CAPTIVE_PORTAL,
+                new CaptivePortal(new CaptivePortalImpl(network).asBinder()));
         appIntent.setFlags(Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT | Intent.FLAG_ACTIVITY_NEW_TASK);
 
         Binder.withCleanCallingIdentity(() ->
                 mContext.startActivityAsUser(appIntent, UserHandle.CURRENT));
     }
 
+    private class CaptivePortalImpl extends ICaptivePortal.Stub {
+        private final Network mNetwork;
+
+        private CaptivePortalImpl(Network network) {
+            mNetwork = network;
+        }
+
+        @Override
+        public void appResponse(final int response) throws RemoteException {
+            if (response == CaptivePortal.APP_RETURN_WANTED_AS_IS) {
+                enforceSettingsPermission();
+            }
+
+            // getNetworkAgentInfoForNetwork is thread-safe
+            final NetworkAgentInfo nai = getNetworkAgentInfoForNetwork(mNetwork);
+            if (nai == null) return;
+
+            // nai.networkMonitor() is thread-safe
+            final INetworkMonitor nm = nai.networkMonitor();
+            if (nm == null) return;
+
+            final long token = Binder.clearCallingIdentity();
+            try {
+                nm.notifyCaptivePortalAppFinished(response);
+            } finally {
+                // Not using Binder.withCleanCallingIdentity() to keep the checked RemoteException
+                Binder.restoreCallingIdentity(token);
+            }
+        }
+
+        @Override
+        public void logEvent(int eventId, String packageName) {
+            enforceSettingsPermission();
+
+            new MetricsLogger().action(eventId, packageName);
+        }
+    }
+
     public boolean avoidBadWifi() {
         return mMultinetworkPolicyTracker.getAvoidBadWifi();
     }