Support Safemode for VCNs.

This CL updates VcnManagementService to support Safemode for VCN
instances. Specifically, VcnGatewayConnections will notify their Vcn
instance when they enter Safemode. Vcn instances will in-turn notify
VcnManagementService, which notifies all registered
UnderlyingNetworkPolicyListeners to update their policies.

Bug: 178140973
Test: atest FrameworksVcnTests
Change-Id: I3336c150e9406b3eb2330d2e86cae2ed835730bb

8 files changed, 252 insertions, 41 deletions

diff --git a/services/core/java/com/android/server/VcnManagementService.java b/services/core/java/com/android/server/VcnManagementService.java
index 916bec27af39..4dce59f23a79 100644
--- a/services/core/java/com/android/server/VcnManagementService.java
+++ b/services/core/java/com/android/server/VcnManagementService.java
@@ -66,6 +66,7 @@ import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
+import java.util.Objects;
 import java.util.concurrent.TimeUnit;
 
 /**
@@ -291,8 +292,9 @@ public class VcnManagementService extends IVcnManagementService.Stub {
                 @NonNull VcnContext vcnContext,
                 @NonNull ParcelUuid subscriptionGroup,
                 @NonNull VcnConfig config,
-                @NonNull TelephonySubscriptionSnapshot snapshot) {
-            return new Vcn(vcnContext, subscriptionGroup, config, snapshot);
+                @NonNull TelephonySubscriptionSnapshot snapshot,
+                @NonNull VcnSafemodeCallback safemodeCallback) {
+            return new Vcn(vcnContext, subscriptionGroup, config, snapshot, safemodeCallback);
         }
 
         /** Gets the subId indicated by the given {@link WifiInfo}. */
@@ -438,7 +440,12 @@ public class VcnManagementService extends IVcnManagementService.Stub {
         // TODO(b/176939047): Support multiple VCNs active at the same time, or limit to one active
         //                    VCN.
 
-        final Vcn newInstance = mDeps.newVcn(mVcnContext, subscriptionGroup, config, mLastSnapshot);
+        final VcnSafemodeCallbackImpl safemodeCallback =
+                new VcnSafemodeCallbackImpl(subscriptionGroup);
+
+        final Vcn newInstance =
+                mDeps.newVcn(
+                        mVcnContext, subscriptionGroup, config, mLastSnapshot, safemodeCallback);
         mVcns.put(subscriptionGroup, newInstance);
 
         // Now that a new VCN has started, notify all registered listeners to refresh their
@@ -536,7 +543,7 @@ public class VcnManagementService extends IVcnManagementService.Stub {
         }
     }
 
-    /** Get current configuration list for testing purposes */
+    /** Get current VCNs for testing purposes */
     @VisibleForTesting(visibility = Visibility.PRIVATE)
     public Map<ParcelUuid, Vcn> getAllVcns() {
         synchronized (mLock) {
@@ -638,8 +645,8 @@ public class VcnManagementService extends IVcnManagementService.Stub {
             synchronized (mLock) {
                 ParcelUuid subGroup = mLastSnapshot.getGroupForSubId(subId);
 
-                // TODO(b/178140910): only mark the Network as VCN-managed if not in safe mode
-                if (mVcns.containsKey(subGroup)) {
+                Vcn vcn = mVcns.get(subGroup);
+                if (vcn != null && vcn.isActive()) {
                     isVcnManagedNetwork = true;
                 }
             }
@@ -651,4 +658,31 @@ public class VcnManagementService extends IVcnManagementService.Stub {
 
         return new VcnUnderlyingNetworkPolicy(false /* isTearDownRequested */, networkCapabilities);
     }
+
+    /** Callback for signalling when a Vcn has entered Safemode. */
+    public interface VcnSafemodeCallback {
+        /** Called by a Vcn to signal that it has entered Safemode. */
+        void onEnteredSafemode();
+    }
+
+    /** VcnSafemodeCallback is used by Vcns to notify VcnManagementService on entering Safemode. */
+    private class VcnSafemodeCallbackImpl implements VcnSafemodeCallback {
+        @NonNull private final ParcelUuid mSubGroup;
+
+        private VcnSafemodeCallbackImpl(@NonNull final ParcelUuid subGroup) {
+            mSubGroup = Objects.requireNonNull(subGroup, "Missing subGroup");
+        }
+
+        @Override
+        public void onEnteredSafemode() {
+            synchronized (mLock) {
+                // Ignore if this subscription group doesn't exist anymore
+                if (!mVcns.containsKey(mSubGroup)) {
+                    return;
+                }
+
+                notifyAllPolicyListenersLocked();
+            }
+        }
+    }
 }
diff --git a/services/core/java/com/android/server/vcn/Vcn.java b/services/core/java/com/android/server/vcn/Vcn.java
index a82f239948ff..5ec527a7d6c4 100644
--- a/services/core/java/com/android/server/vcn/Vcn.java
+++ b/services/core/java/com/android/server/vcn/Vcn.java
@@ -29,6 +29,7 @@ import android.util.Slog;
 
 import com.android.internal.annotations.VisibleForTesting;
 import com.android.internal.annotations.VisibleForTesting.Visibility;
+import com.android.server.VcnManagementService.VcnSafemodeCallback;
 import com.android.server.vcn.TelephonySubscriptionTracker.TelephonySubscriptionSnapshot;
 
 import java.util.Collections;
@@ -37,6 +38,7 @@ import java.util.HashSet;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Set;
+import java.util.concurrent.atomic.AtomicBoolean;
 
 /**
  * Represents an single instance of a VCN.
@@ -82,10 +84,19 @@ public class Vcn extends Handler {
     /** Triggers an immediate teardown of the entire Vcn, including GatewayConnections. */
     private static final int MSG_CMD_TEARDOWN = MSG_CMD_BASE;
 
+    /**
+     * Causes this VCN to immediately enter Safemode.
+     *
+     * <p>Upon entering Safemode, the VCN will unregister its RequestListener, tear down all of its
+     * VcnGatewayConnections, and notify VcnManagementService that it is in Safemode.
+     */
+    private static final int MSG_CMD_ENTER_SAFEMODE = MSG_CMD_BASE + 1;
+
     @NonNull private final VcnContext mVcnContext;
     @NonNull private final ParcelUuid mSubscriptionGroup;
     @NonNull private final Dependencies mDeps;
     @NonNull private final VcnNetworkRequestListener mRequestListener;
+    @NonNull private final VcnSafemodeCallback mVcnSafemodeCallback;
 
     @NonNull
     private final Map<VcnGatewayConnectionConfig, VcnGatewayConnection> mVcnGatewayConnections =
@@ -94,14 +105,33 @@ public class Vcn extends Handler {
     @NonNull private VcnConfig mConfig;
     @NonNull private TelephonySubscriptionSnapshot mLastSnapshot;
 
-    private boolean mIsRunning = true;
+    /**
+     * Whether this Vcn instance is active and running.
+     *
+     * <p>The value will be {@code true} while running. It will be {@code false} if the VCN has been
+     * shut down or has entered safe mode.
+     *
+     * <p>This AtomicBoolean is required in order to ensure consistency and correctness across
+     * multiple threads. Unlike the rest of the Vcn, this is queried synchronously on Binder threads
+     * from VcnManagementService, and therefore cannot rely on guarantees of running on the VCN
+     * Looper.
+     */
+    // TODO(b/179429339): update when exiting safemode (when a new VcnConfig is provided)
+    private final AtomicBoolean mIsActive = new AtomicBoolean(true);
 
     public Vcn(
             @NonNull VcnContext vcnContext,
             @NonNull ParcelUuid subscriptionGroup,
             @NonNull VcnConfig config,
-            @NonNull TelephonySubscriptionSnapshot snapshot) {
-        this(vcnContext, subscriptionGroup, config, snapshot, new Dependencies());
+            @NonNull TelephonySubscriptionSnapshot snapshot,
+            @NonNull VcnSafemodeCallback vcnSafemodeCallback) {
+        this(
+                vcnContext,
+                subscriptionGroup,
+                config,
+                snapshot,
+                vcnSafemodeCallback,
+                new Dependencies());
     }
 
     @VisibleForTesting(visibility = Visibility.PRIVATE)
@@ -110,10 +140,13 @@ public class Vcn extends Handler {
             @NonNull ParcelUuid subscriptionGroup,
             @NonNull VcnConfig config,
             @NonNull TelephonySubscriptionSnapshot snapshot,
+            @NonNull VcnSafemodeCallback vcnSafemodeCallback,
             @NonNull Dependencies deps) {
         super(Objects.requireNonNull(vcnContext, "Missing vcnContext").getLooper());
         mVcnContext = vcnContext;
         mSubscriptionGroup = Objects.requireNonNull(subscriptionGroup, "Missing subscriptionGroup");
+        mVcnSafemodeCallback =
+                Objects.requireNonNull(vcnSafemodeCallback, "Missing vcnSafemodeCallback");
         mDeps = Objects.requireNonNull(deps, "Missing deps");
         mRequestListener = new VcnNetworkRequestListener();
 
@@ -143,6 +176,11 @@ public class Vcn extends Handler {
         sendMessageAtFrontOfQueue(obtainMessage(MSG_CMD_TEARDOWN));
     }
 
+    /** Synchronously checks whether this Vcn is active. */
+    public boolean isActive() {
+        return mIsActive.get();
+    }
+
     /** Get current Gateways for testing purposes */
     @VisibleForTesting(visibility = Visibility.PRIVATE)
     public Set<VcnGatewayConnection> getVcnGatewayConnections() {
@@ -160,7 +198,7 @@ public class Vcn extends Handler {
 
     @Override
     public void handleMessage(@NonNull Message msg) {
-        if (!mIsRunning) {
+        if (!isActive()) {
             return;
         }
 
@@ -177,6 +215,9 @@ public class Vcn extends Handler {
             case MSG_CMD_TEARDOWN:
                 handleTeardown();
                 break;
+            case MSG_CMD_ENTER_SAFEMODE:
+                handleEnterSafemode();
+                break;
             default:
                 Slog.wtf(getLogTag(), "Unknown msg.what: " + msg.what);
         }
@@ -198,7 +239,13 @@ public class Vcn extends Handler {
             gatewayConnection.teardownAsynchronously();
         }
 
-        mIsRunning = false;
+        mIsActive.set(false);
+    }
+
+    private void handleEnterSafemode() {
+        handleTeardown();
+
+        mVcnSafemodeCallback.onEnteredSafemode();
     }
 
     private void handleNetworkRequested(
@@ -233,7 +280,8 @@ public class Vcn extends Handler {
                                 mVcnContext,
                                 mSubscriptionGroup,
                                 mLastSnapshot,
-                                gatewayConnectionConfig);
+                                gatewayConnectionConfig,
+                                new VcnGatewayStatusCallbackImpl());
                 mVcnGatewayConnections.put(gatewayConnectionConfig, vcnGatewayConnection);
             }
         }
@@ -242,7 +290,7 @@ public class Vcn extends Handler {
     private void handleSubscriptionsChanged(@NonNull TelephonySubscriptionSnapshot snapshot) {
         mLastSnapshot = snapshot;
 
-        if (mIsRunning) {
+        if (isActive()) {
             for (VcnGatewayConnection gatewayConnection : mVcnGatewayConnections.values()) {
                 gatewayConnection.updateSubscriptionSnapshot(mLastSnapshot);
             }
@@ -271,6 +319,20 @@ public class Vcn extends Handler {
         return 52;
     }
 
+    /** Callback used for passing status signals from a VcnGatewayConnection to its managing Vcn. */
+    @VisibleForTesting(visibility = Visibility.PACKAGE)
+    public interface VcnGatewayStatusCallback {
+        /** Called by a VcnGatewayConnection to indicate that it has entered Safemode. */
+        void onEnteredSafemode();
+    }
+
+    private class VcnGatewayStatusCallbackImpl implements VcnGatewayStatusCallback {
+        @Override
+        public void onEnteredSafemode() {
+            sendMessage(obtainMessage(MSG_CMD_ENTER_SAFEMODE));
+        }
+    }
+
     /** External dependencies used by Vcn, for injection in tests */
     @VisibleForTesting(visibility = Visibility.PRIVATE)
     public static class Dependencies {
@@ -279,9 +341,14 @@ public class Vcn extends Handler {
                 VcnContext vcnContext,
                 ParcelUuid subscriptionGroup,
                 TelephonySubscriptionSnapshot snapshot,
-                VcnGatewayConnectionConfig connectionConfig) {
+                VcnGatewayConnectionConfig connectionConfig,
+                VcnGatewayStatusCallback gatewayStatusCallback) {
             return new VcnGatewayConnection(
-                    vcnContext, subscriptionGroup, snapshot, connectionConfig);
+                    vcnContext,
+                    subscriptionGroup,
+                    snapshot,
+                    connectionConfig,
+                    gatewayStatusCallback);
         }
     }
 }
diff --git a/services/core/java/com/android/server/vcn/VcnGatewayConnection.java b/services/core/java/com/android/server/vcn/VcnGatewayConnection.java
index 853bb4324f90..bd82fcc1447b 100644
--- a/services/core/java/com/android/server/vcn/VcnGatewayConnection.java
+++ b/services/core/java/com/android/server/vcn/VcnGatewayConnection.java
@@ -69,6 +69,7 @@ import com.android.internal.util.StateMachine;
 import com.android.server.vcn.TelephonySubscriptionTracker.TelephonySubscriptionSnapshot;
 import com.android.server.vcn.UnderlyingNetworkTracker.UnderlyingNetworkRecord;
 import com.android.server.vcn.UnderlyingNetworkTracker.UnderlyingNetworkTrackerCallback;
+import com.android.server.vcn.Vcn.VcnGatewayStatusCallback;
 
 import java.io.IOException;
 import java.net.Inet4Address;
@@ -412,6 +413,7 @@ public class VcnGatewayConnection extends StateMachine {
     @NonNull private final ParcelUuid mSubscriptionGroup;
     @NonNull private final UnderlyingNetworkTracker mUnderlyingNetworkTracker;
     @NonNull private final VcnGatewayConnectionConfig mConnectionConfig;
+    @NonNull private final VcnGatewayStatusCallback mGatewayStatusCallback;
     @NonNull private final Dependencies mDeps;
 
     @NonNull private final VcnUnderlyingNetworkTrackerCallback mUnderlyingNetworkTrackerCallback;
@@ -487,8 +489,15 @@ public class VcnGatewayConnection extends StateMachine {
             @NonNull VcnContext vcnContext,
             @NonNull ParcelUuid subscriptionGroup,
             @NonNull TelephonySubscriptionSnapshot snapshot,
-            @NonNull VcnGatewayConnectionConfig connectionConfig) {
-        this(vcnContext, subscriptionGroup, snapshot, connectionConfig, new Dependencies());
+            @NonNull VcnGatewayConnectionConfig connectionConfig,
+            @NonNull VcnGatewayStatusCallback gatewayStatusCallback) {
+        this(
+                vcnContext,
+                subscriptionGroup,
+                snapshot,
+                connectionConfig,
+                gatewayStatusCallback,
+                new Dependencies());
     }
 
     @VisibleForTesting(visibility = Visibility.PRIVATE)
@@ -497,11 +506,14 @@ public class VcnGatewayConnection extends StateMachine {
             @NonNull ParcelUuid subscriptionGroup,
             @NonNull TelephonySubscriptionSnapshot snapshot,
             @NonNull VcnGatewayConnectionConfig connectionConfig,
+            @NonNull VcnGatewayStatusCallback gatewayStatusCallback,
             @NonNull Dependencies deps) {
         super(TAG, Objects.requireNonNull(vcnContext, "Missing vcnContext").getLooper());
         mVcnContext = vcnContext;
         mSubscriptionGroup = Objects.requireNonNull(subscriptionGroup, "Missing subscriptionGroup");
         mConnectionConfig = Objects.requireNonNull(connectionConfig, "Missing connectionConfig");
+        mGatewayStatusCallback =
+                Objects.requireNonNull(gatewayStatusCallback, "Missing gatewayStatusCallback");
         mDeps = Objects.requireNonNull(deps, "Missing deps");
 
         synchronized (mLock) {
diff --git a/tests/vcn/java/android/net/vcn/VcnGatewayConnectionConfigTest.java b/tests/vcn/java/android/net/vcn/VcnGatewayConnectionConfigTest.java
index 86a15912b6b4..3e659d0bc128 100644
--- a/tests/vcn/java/android/net/vcn/VcnGatewayConnectionConfigTest.java
+++ b/tests/vcn/java/android/net/vcn/VcnGatewayConnectionConfigTest.java
@@ -59,12 +59,17 @@ public class VcnGatewayConnectionConfigTest {
 
     // Public for use in VcnGatewayConnectionTest
     public static VcnGatewayConnectionConfig buildTestConfig() {
+        return buildTestConfigWithExposedCaps(EXPOSED_CAPS);
+    }
+
+    // Public for use in VcnGatewayConnectionTest
+    public static VcnGatewayConnectionConfig buildTestConfigWithExposedCaps(int... exposedCaps) {
         final VcnGatewayConnectionConfig.Builder builder =
                 new VcnGatewayConnectionConfig.Builder()
                         .setRetryInterval(RETRY_INTERVALS_MS)
                         .setMaxMtu(MAX_MTU);
 
-        for (int caps : EXPOSED_CAPS) {
+        for (int caps : exposedCaps) {
             builder.addExposedCapability(caps);
         }
 
diff --git a/tests/vcn/java/com/android/server/VcnManagementServiceTest.java b/tests/vcn/java/com/android/server/VcnManagementServiceTest.java
index e32e1e831f83..485964487fda 100644
--- a/tests/vcn/java/com/android/server/VcnManagementServiceTest.java
+++ b/tests/vcn/java/com/android/server/VcnManagementServiceTest.java
@@ -66,6 +66,7 @@ import android.telephony.TelephonyManager;
 import androidx.test.filters.SmallTest;
 import androidx.test.runner.AndroidJUnit4;
 
+import com.android.server.VcnManagementService.VcnSafemodeCallback;
 import com.android.server.vcn.TelephonySubscriptionTracker;
 import com.android.server.vcn.Vcn;
 import com.android.server.vcn.VcnContext;
@@ -142,6 +143,9 @@ public class VcnManagementServiceTest {
     private final TelephonySubscriptionTracker mSubscriptionTracker =
             mock(TelephonySubscriptionTracker.class);
 
+    private final ArgumentCaptor<VcnSafemodeCallback> mSafemodeCallbackCaptor =
+            ArgumentCaptor.forClass(VcnSafemodeCallback.class);
+
     private final VcnManagementService mVcnMgmtSvc;
 
     private final IVcnUnderlyingNetworkPolicyListener mMockPolicyListener =
@@ -184,7 +188,7 @@ public class VcnManagementServiceTest {
         doAnswer((invocation) -> {
             // Mock-within a doAnswer is safe, because it doesn't actually run nested.
             return mock(Vcn.class);
-        }).when(mMockDeps).newVcn(any(), any(), any(), any());
+        }).when(mMockDeps).newVcn(any(), any(), any(), any(), any());
 
         final PersistableBundle bundle =
                 PersistableBundleUtils.fromMap(
@@ -307,7 +311,7 @@ public class VcnManagementServiceTest {
         TelephonySubscriptionSnapshot snapshot =
                 triggerSubscriptionTrackerCbAndGetSnapshot(Collections.singleton(TEST_UUID_1));
         verify(mMockDeps)
-                .newVcn(eq(mVcnContext), eq(TEST_UUID_1), eq(TEST_VCN_CONFIG), eq(snapshot));
+                .newVcn(eq(mVcnContext), eq(TEST_UUID_1), eq(TEST_VCN_CONFIG), eq(snapshot), any());
     }
 
     @Test
@@ -485,7 +489,8 @@ public class VcnManagementServiceTest {
                         eq(mVcnContext),
                         eq(TEST_UUID_2),
                         eq(TEST_VCN_CONFIG),
-                        eq(TelephonySubscriptionSnapshot.EMPTY_SNAPSHOT));
+                        eq(TelephonySubscriptionSnapshot.EMPTY_SNAPSHOT),
+                        any());
 
         // Verify Vcn is updated if it was previously started
         mVcnMgmtSvc.setVcnConfig(TEST_UUID_2, TEST_VCN_CONFIG, TEST_PACKAGE_NAME);
@@ -634,4 +639,25 @@ public class VcnManagementServiceTest {
 
         verify(mMockPolicyListener).onPolicyChanged();
     }
+
+    @Test
+    public void testVcnSafemodeCallbackOnEnteredSafemode() throws Exception {
+        TelephonySubscriptionSnapshot snapshot =
+                triggerSubscriptionTrackerCbAndGetSnapshot(Collections.singleton(TEST_UUID_1));
+        verify(mMockDeps)
+                .newVcn(
+                        eq(mVcnContext),
+                        eq(TEST_UUID_1),
+                        eq(TEST_VCN_CONFIG),
+                        eq(snapshot),
+                        mSafemodeCallbackCaptor.capture());
+
+        mVcnMgmtSvc.addVcnUnderlyingNetworkPolicyListener(mMockPolicyListener);
+
+        VcnSafemodeCallback safemodeCallback = mSafemodeCallbackCaptor.getValue();
+        safemodeCallback.onEnteredSafemode();
+
+        assertFalse(mVcnMgmtSvc.getAllVcns().get(TEST_UUID_1).isActive());
+        verify(mMockPolicyListener).onPolicyChanged();
+    }
 }
diff --git a/tests/vcn/java/com/android/server/vcn/VcnGatewayConnectionDisconnectedStateTest.java b/tests/vcn/java/com/android/server/vcn/VcnGatewayConnectionDisconnectedStateTest.java
index fbaae6f534a9..8643d8a2ea8a 100644
--- a/tests/vcn/java/com/android/server/vcn/VcnGatewayConnectionDisconnectedStateTest.java
+++ b/tests/vcn/java/com/android/server/vcn/VcnGatewayConnectionDisconnectedStateTest.java
@@ -45,7 +45,12 @@ public class VcnGatewayConnectionDisconnectedStateTest extends VcnGatewayConnect
     public void testEnterWhileNotRunningTriggersQuit() throws Exception {
         final VcnGatewayConnection vgc =
                 new VcnGatewayConnection(
-                        mVcnContext, TEST_SUB_GRP, TEST_SUBSCRIPTION_SNAPSHOT, mConfig, mDeps);
+                        mVcnContext,
+                        TEST_SUB_GRP,
+                        TEST_SUBSCRIPTION_SNAPSHOT,
+                        mConfig,
+                        mGatewayStatusCallback,
+                        mDeps);
 
         vgc.setIsRunning(false);
         vgc.transitionTo(vgc.mDisconnectedState);
diff --git a/tests/vcn/java/com/android/server/vcn/VcnGatewayConnectionTestBase.java b/tests/vcn/java/com/android/server/vcn/VcnGatewayConnectionTestBase.java
index df1341cce20f..333b5b990dde 100644
--- a/tests/vcn/java/com/android/server/vcn/VcnGatewayConnectionTestBase.java
+++ b/tests/vcn/java/com/android/server/vcn/VcnGatewayConnectionTestBase.java
@@ -43,6 +43,7 @@ import android.os.test.TestLooper;
 
 import com.android.server.IpSecService;
 import com.android.server.vcn.TelephonySubscriptionTracker.TelephonySubscriptionSnapshot;
+import com.android.server.vcn.Vcn.VcnGatewayStatusCallback;
 
 import org.junit.Before;
 import org.mockito.ArgumentCaptor;
@@ -80,6 +81,7 @@ public class VcnGatewayConnectionTestBase {
     @NonNull protected final VcnNetworkProvider mVcnNetworkProvider;
     @NonNull protected final VcnContext mVcnContext;
     @NonNull protected final VcnGatewayConnectionConfig mConfig;
+    @NonNull protected final VcnGatewayStatusCallback mGatewayStatusCallback;
     @NonNull protected final VcnGatewayConnection.Dependencies mDeps;
     @NonNull protected final UnderlyingNetworkTracker mUnderlyingNetworkTracker;
 
@@ -94,6 +96,7 @@ public class VcnGatewayConnectionTestBase {
         mVcnNetworkProvider = mock(VcnNetworkProvider.class);
         mVcnContext = mock(VcnContext.class);
         mConfig = VcnGatewayConnectionConfigTest.buildTestConfig();
+        mGatewayStatusCallback = mock(VcnGatewayStatusCallback.class);
         mDeps = mock(VcnGatewayConnection.Dependencies.class);
         mUnderlyingNetworkTracker = mock(UnderlyingNetworkTracker.class);
 
@@ -123,7 +126,12 @@ public class VcnGatewayConnectionTestBase {
 
         mGatewayConnection =
                 new VcnGatewayConnection(
-                        mVcnContext, TEST_SUB_GRP, TEST_SUBSCRIPTION_SNAPSHOT, mConfig, mDeps);
+                        mVcnContext,
+                        TEST_SUB_GRP,
+                        TEST_SUBSCRIPTION_SNAPSHOT,
+                        mConfig,
+                        mGatewayStatusCallback,
+                        mDeps);
     }
 
     protected IpSecTransform makeDummyIpSecTransform() throws Exception {
diff --git a/tests/vcn/java/com/android/server/vcn/VcnTest.java b/tests/vcn/java/com/android/server/vcn/VcnTest.java
index 0c1df763a08e..66cbf84619ab 100644
--- a/tests/vcn/java/com/android/server/vcn/VcnTest.java
+++ b/tests/vcn/java/com/android/server/vcn/VcnTest.java
@@ -16,22 +16,27 @@
 
 package com.android.server.vcn;
 
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.mockito.Matchers.any;
 import static org.mockito.Matchers.eq;
 import static org.mockito.Mockito.doAnswer;
 import static org.mockito.Mockito.doReturn;
 import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 
 import android.content.Context;
 import android.net.NetworkRequest;
 import android.net.vcn.VcnConfig;
+import android.net.vcn.VcnGatewayConnectionConfig;
 import android.net.vcn.VcnGatewayConnectionConfigTest;
 import android.os.ParcelUuid;
 import android.os.test.TestLooper;
 
+import com.android.server.VcnManagementService.VcnSafemodeCallback;
 import com.android.server.vcn.TelephonySubscriptionTracker.TelephonySubscriptionSnapshot;
+import com.android.server.vcn.Vcn.VcnGatewayStatusCallback;
 import com.android.server.vcn.VcnNetworkProvider.NetworkRequestListener;
 
 import org.junit.Before;
@@ -51,9 +56,13 @@ public class VcnTest {
     private VcnContext mVcnContext;
     private TelephonySubscriptionSnapshot mSubscriptionSnapshot;
     private VcnNetworkProvider mVcnNetworkProvider;
+    private VcnSafemodeCallback mVcnSafemodeCallback;
     private Vcn.Dependencies mDeps;
 
+    private ArgumentCaptor<VcnGatewayStatusCallback> mGatewayStatusCallbackCaptor;
+
     private TestLooper mTestLooper;
+    private VcnGatewayConnectionConfig mGatewayConnectionConfig;
     private VcnConfig mConfig;
     private Vcn mVcn;
 
@@ -63,6 +72,7 @@ public class VcnTest {
         mVcnContext = mock(VcnContext.class);
         mSubscriptionSnapshot = mock(TelephonySubscriptionSnapshot.class);
         mVcnNetworkProvider = mock(VcnNetworkProvider.class);
+        mVcnSafemodeCallback = mock(VcnSafemodeCallback.class);
         mDeps = mock(Vcn.Dependencies.class);
 
         mTestLooper = new TestLooper();
@@ -76,15 +86,26 @@ public class VcnTest {
         doAnswer((invocation) -> {
             // Mock-within a doAnswer is safe, because it doesn't actually run nested.
             return mock(VcnGatewayConnection.class);
-        }).when(mDeps).newVcnGatewayConnection(any(), any(), any(), any());
+        }).when(mDeps).newVcnGatewayConnection(any(), any(), any(), any(), any());
 
-        mConfig =
-                new VcnConfig.Builder(mContext)
-                        .addGatewayConnectionConfig(
-                                VcnGatewayConnectionConfigTest.buildTestConfig())
-                        .build();
+        mGatewayStatusCallbackCaptor = ArgumentCaptor.forClass(VcnGatewayStatusCallback.class);
 
-        mVcn = new Vcn(mVcnContext, TEST_SUB_GROUP, mConfig, mSubscriptionSnapshot, mDeps);
+        final VcnConfig.Builder configBuilder = new VcnConfig.Builder(mContext);
+        for (final int capability : VcnGatewayConnectionConfigTest.EXPOSED_CAPS) {
+            configBuilder.addGatewayConnectionConfig(
+                    VcnGatewayConnectionConfigTest.buildTestConfigWithExposedCaps(capability));
+        }
+        configBuilder.addGatewayConnectionConfig(VcnGatewayConnectionConfigTest.buildTestConfig());
+        mConfig = configBuilder.build();
+
+        mVcn =
+                new Vcn(
+                        mVcnContext,
+                        TEST_SUB_GROUP,
+                        mConfig,
+                        mSubscriptionSnapshot,
+                        mVcnSafemodeCallback,
+                        mDeps);
     }
 
     private NetworkRequestListener verifyAndGetRequestListener() {
@@ -95,23 +116,22 @@ public class VcnTest {
         return mNetworkRequestListenerCaptor.getValue();
     }
 
-    private NetworkRequest getNetworkRequestWithCapabilities(int[] networkCapabilities) {
-        final NetworkRequest.Builder builder = new NetworkRequest.Builder();
-        for (final int netCapability : networkCapabilities) {
-            builder.addCapability(netCapability);
+    private void startVcnGatewayWithCapabilities(
+            NetworkRequestListener requestListener, int... netCapabilities) {
+        final NetworkRequest.Builder requestBuilder = new NetworkRequest.Builder();
+        for (final int netCapability : netCapabilities) {
+            requestBuilder.addCapability(netCapability);
         }
-        return builder.build();
+
+        requestListener.onNetworkRequested(requestBuilder.build(), NETWORK_SCORE, PROVIDER_ID);
+        mTestLooper.dispatchAll();
     }
 
     @Test
     public void testSubscriptionSnapshotUpdatesVcnGatewayConnections() {
         final NetworkRequestListener requestListener = verifyAndGetRequestListener();
-
-        requestListener.onNetworkRequested(
-                getNetworkRequestWithCapabilities(VcnGatewayConnectionConfigTest.EXPOSED_CAPS),
-                NETWORK_SCORE,
-                PROVIDER_ID);
-        mTestLooper.dispatchAll();
+        startVcnGatewayWithCapabilities(
+                requestListener, VcnGatewayConnectionConfigTest.EXPOSED_CAPS);
 
         final Set<VcnGatewayConnection> gatewayConnections = mVcn.getVcnGatewayConnections();
         assertFalse(gatewayConnections.isEmpty());
@@ -126,4 +146,38 @@ public class VcnTest {
             verify(gateway).updateSubscriptionSnapshot(eq(updatedSnapshot));
         }
     }
+
+    @Test
+    public void testGatewayEnteringSafemodeNotifiesVcn() {
+        final NetworkRequestListener requestListener = verifyAndGetRequestListener();
+        for (final int capability : VcnGatewayConnectionConfigTest.EXPOSED_CAPS) {
+            startVcnGatewayWithCapabilities(requestListener, capability);
+        }
+
+        // Each Capability in EXPOSED_CAPS was split into a separate VcnGatewayConnection in #setUp.
+        // Expect one VcnGatewayConnection per capability.
+        final int numExpectedGateways = VcnGatewayConnectionConfigTest.EXPOSED_CAPS.length;
+
+        final Set<VcnGatewayConnection> gatewayConnections = mVcn.getVcnGatewayConnections();
+        assertEquals(numExpectedGateways, gatewayConnections.size());
+        verify(mDeps, times(numExpectedGateways))
+                .newVcnGatewayConnection(
+                        eq(mVcnContext),
+                        eq(TEST_SUB_GROUP),
+                        eq(mSubscriptionSnapshot),
+                        any(),
+                        mGatewayStatusCallbackCaptor.capture());
+
+        // Doesn't matter which callback this gets - any Gateway entering Safemode should shut down
+        // all Gateways
+        final VcnGatewayStatusCallback statusCallback = mGatewayStatusCallbackCaptor.getValue();
+        statusCallback.onEnteredSafemode();
+        mTestLooper.dispatchAll();
+
+        for (final VcnGatewayConnection gatewayConnection : gatewayConnections) {
+            verify(gatewayConnection).teardownAsynchronously();
+        }
+        verify(mVcnNetworkProvider).unregisterListener(requestListener);
+        verify(mVcnSafemodeCallback).onEnteredSafemode();
+    }
 }