Notify PolicyListeners to refresh their policy on VCN changes.

This CL updates VcnManagementService to notify all registered
VcnUnderlyingNetworkPolicyListeners to refresh their
UnderlyingNetworkPolicy when any VCN is added or removed.

Bug: 175914059
Test: atest FrameworksVcnTests
Change-Id: Ie87f4aa3401c6c4ba9f932130a1d475e35f59d4e

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

@@ -397,7 +397,7 @@ public class VcnManagementService extends IVcnManagementService.Stub {
                                 // correct instance is torn down. This could happen as a result of a
                                 // Carrier App manually removing/adding a VcnConfig.
                                 if (mVcns.get(uuidToTeardown) == instanceToTeardown) {
-                                    mVcns.remove(uuidToTeardown).teardownAsynchronously();
+                                    stopVcnLocked(uuidToTeardown);
                                 }
                             }
                         }, instanceToTeardown, CARRIER_PRIVILEGES_LOST_TEARDOWN_DELAY_MS);
@@ -410,6 +410,27 @@ public class VcnManagementService extends IVcnManagementService.Stub {
         }
     }
 
+    @GuardedBy("mLock")
+    private void stopVcnLocked(@NonNull ParcelUuid uuidToTeardown) {
+        final Vcn vcnToTeardown = mVcns.remove(uuidToTeardown);
+        if (vcnToTeardown == null) {
+            return;
+        }
+
+        vcnToTeardown.teardownAsynchronously();
+
+        // Now that the VCN is removed, notify all registered listeners to refresh their
+        // UnderlyingNetworkPolicy.
+        notifyAllPolicyListenersLocked();
+    }
+
+    @GuardedBy("mLock")
+    private void notifyAllPolicyListenersLocked() {
+        for (final PolicyListenerBinderDeath policyListener : mRegisteredPolicyListeners.values()) {
+            Binder.withCleanCallingIdentity(() -> policyListener.mListener.onPolicyChanged());
+        }
+    }
+
     @GuardedBy("mLock")
     private void startVcnLocked(@NonNull ParcelUuid subscriptionGroup, @NonNull VcnConfig config) {
         Slog.v(TAG, "Starting VCN config for subGrp: " + subscriptionGroup);
@@ -419,6 +440,10 @@ public class VcnManagementService extends IVcnManagementService.Stub {
 
         final Vcn newInstance = mDeps.newVcn(mVcnContext, subscriptionGroup, config, mLastSnapshot);
         mVcns.put(subscriptionGroup, newInstance);
+
+        // Now that a new VCN has started, notify all registered listeners to refresh their
+        // UnderlyingNetworkPolicy.
+        notifyAllPolicyListenersLocked();
     }
 
     @GuardedBy("mLock")
@@ -481,9 +506,7 @@ public class VcnManagementService extends IVcnManagementService.Stub {
             synchronized (mLock) {
                 mConfigs.remove(subscriptionGroup);
 
-                if (mVcns.containsKey(subscriptionGroup)) {
-                    mVcns.remove(subscriptionGroup).teardownAsynchronously();
-                }
+                stopVcnLocked(subscriptionGroup);
 
                 writeConfigsToDiskLocked();
             }

tests/vcn/java/com/android/server/VcnManagementServiceTest.java

@@ -314,6 +314,7 @@ public class VcnManagementServiceTest {
     public void testTelephonyNetworkTrackerCallbackStopsInstances() throws Exception {
         final TelephonySubscriptionTrackerCallback cb = getTelephonySubscriptionTrackerCallback();
         final Vcn vcn = startAndGetVcnInstance(TEST_UUID_2);
+        mVcnMgmtSvc.addVcnUnderlyingNetworkPolicyListener(mMockPolicyListener);
 
         triggerSubscriptionTrackerCbAndGetSnapshot(Collections.emptySet());
 
@@ -321,6 +322,7 @@ public class VcnManagementServiceTest {
         mTestLooper.moveTimeForward(VcnManagementService.CARRIER_PRIVILEGES_LOST_TEARDOWN_DELAY_MS);
         mTestLooper.dispatchAll();
         verify(vcn).teardownAsynchronously();
+        verify(mMockPolicyListener).onPolicyChanged();
     }
 
     @Test
@@ -391,6 +393,7 @@ public class VcnManagementServiceTest {
             mVcnMgmtSvc.setVcnConfig(TEST_UUID_1, TEST_VCN_CONFIG, TEST_PACKAGE_NAME);
             fail("Expected security exception for non system user");
         } catch (SecurityException expected) {
+            verify(mMockPolicyListener, never()).onPolicyChanged();
         }
     }
 
@@ -402,6 +405,7 @@ public class VcnManagementServiceTest {
             mVcnMgmtSvc.setVcnConfig(TEST_UUID_1, TEST_VCN_CONFIG, TEST_PACKAGE_NAME);
             fail("Expected security exception for missing carrier privileges");
         } catch (SecurityException expected) {
+            verify(mMockPolicyListener, never()).onPolicyChanged();
         }
     }
 
@@ -411,6 +415,7 @@ public class VcnManagementServiceTest {
             mVcnMgmtSvc.setVcnConfig(TEST_UUID_1, TEST_VCN_CONFIG, "IncorrectPackage");
             fail("Expected exception due to mismatched packages in config and method call");
         } catch (IllegalArgumentException expected) {
+            verify(mMockPolicyListener, never()).onPolicyChanged();
         }
     }
 
@@ -610,4 +615,23 @@ public class VcnManagementServiceTest {
 
         verify(vcnInstance).updateSubscriptionSnapshot(eq(snapshot));
     }
+
+    @Test
+    public void testAddNewVcnUpdatesPolicyListener() throws Exception {
+        mVcnMgmtSvc.addVcnUnderlyingNetworkPolicyListener(mMockPolicyListener);
+
+        mVcnMgmtSvc.setVcnConfig(TEST_UUID_2, TEST_VCN_CONFIG, TEST_PACKAGE_NAME);
+
+        verify(mMockPolicyListener).onPolicyChanged();
+    }
+
+    @Test
+    public void testRemoveVcnUpdatesPolicyListener() throws Exception {
+        mVcnMgmtSvc.setVcnConfig(TEST_UUID_2, TEST_VCN_CONFIG, TEST_PACKAGE_NAME);
+        mVcnMgmtSvc.addVcnUnderlyingNetworkPolicyListener(mMockPolicyListener);
+
+        mVcnMgmtSvc.clearVcnConfig(TEST_UUID_2);
+
+        verify(mMockPolicyListener).onPolicyChanged();
+    }
 }