Support parsing VcnGatewayConnectionConfig without UnderlyingNetworkPriorities

This commit fixes the NullPointerException issue in converting a
PersistableBundle without UnderlyingNetworkPriorities to a
VcnGatewayConnectionConfig, by adding a null check and building
the VcnGatewayConnectionConfig with the default
UnderlyingNetworkPriority list.

Bug: 209142575
Test: atest FrameworksVcnTests (new tests), CtsVcnTestCases
Change-Id: I888d2994c86ba250c3fc9ee1851dccb5e6ef3e77

2 files changed, 38 insertions, 9 deletions

diff --git a/core/java/android/net/vcn/VcnGatewayConnectionConfig.java b/core/java/android/net/vcn/VcnGatewayConnectionConfig.java
index 0bd146cbc1b4..55d3ecd2c92f 100644
--- a/core/java/android/net/vcn/VcnGatewayConnectionConfig.java
+++ b/core/java/android/net/vcn/VcnGatewayConnectionConfig.java
@@ -198,7 +198,10 @@ public final class VcnGatewayConnectionConfig {
     private static final String EXPOSED_CAPABILITIES_KEY = "mExposedCapabilities";
     @NonNull private final SortedSet<Integer> mExposedCapabilities;
 
-    private static final String UNDERLYING_NETWORK_PRIORITIES_KEY = "mUnderlyingNetworkPriorities";
+    /** @hide */
+    @VisibleForTesting(visibility = Visibility.PRIVATE)
+    public static final String UNDERLYING_NETWORK_PRIORITIES_KEY = "mUnderlyingNetworkPriorities";
+
     @NonNull private final LinkedHashSet<VcnUnderlyingNetworkPriority> mUnderlyingNetworkPriorities;
 
     private static final String MAX_MTU_KEY = "mMaxMtu";
@@ -229,6 +232,8 @@ public final class VcnGatewayConnectionConfig {
         validate();
     }
 
+    // Null check MUST be done for all new fields added to VcnGatewayConnectionConfig, to avoid
+    // crashes when parsing PersistableBundle built on old platforms.
     /** @hide */
     @VisibleForTesting(visibility = Visibility.PRIVATE)
     public VcnGatewayConnectionConfig(@NonNull PersistableBundle in) {
@@ -239,19 +244,30 @@ public final class VcnGatewayConnectionConfig {
 
         final PersistableBundle exposedCapsBundle =
                 in.getPersistableBundle(EXPOSED_CAPABILITIES_KEY);
-        final PersistableBundle networkPrioritiesBundle =
-                in.getPersistableBundle(UNDERLYING_NETWORK_PRIORITIES_KEY);
-
         mGatewayConnectionName = in.getString(GATEWAY_CONNECTION_NAME_KEY);
         mTunnelConnectionParams =
                 TunnelConnectionParamsUtils.fromPersistableBundle(tunnelConnectionParamsBundle);
         mExposedCapabilities = new TreeSet<>(PersistableBundleUtils.toList(
                 exposedCapsBundle, PersistableBundleUtils.INTEGER_DESERIALIZER));
-        mUnderlyingNetworkPriorities =
-                new LinkedHashSet<>(
-                        PersistableBundleUtils.toList(
-                                networkPrioritiesBundle,
-                                VcnUnderlyingNetworkPriority::fromPersistableBundle));
+
+        final PersistableBundle networkPrioritiesBundle =
+                in.getPersistableBundle(UNDERLYING_NETWORK_PRIORITIES_KEY);
+
+        if (networkPrioritiesBundle == null) {
+            // UNDERLYING_NETWORK_PRIORITIES_KEY was added in Android T. Thus
+            // VcnGatewayConnectionConfig created on old platforms will not have this data and will
+            // be assigned with the default value
+            mUnderlyingNetworkPriorities =
+                    new LinkedHashSet<>(DEFAULT_UNDERLYING_NETWORK_PRIORITIES);
+
+        } else {
+            mUnderlyingNetworkPriorities =
+                    new LinkedHashSet<>(
+                            PersistableBundleUtils.toList(
+                                    networkPrioritiesBundle,
+                                    VcnUnderlyingNetworkPriority::fromPersistableBundle));
+        }
+
         mRetryIntervalsMs = in.getLongArray(RETRY_INTERVAL_MS_KEY);
         mMaxMtu = in.getInt(MAX_MTU_KEY);
 
diff --git a/tests/vcn/java/android/net/vcn/VcnGatewayConnectionConfigTest.java b/tests/vcn/java/android/net/vcn/VcnGatewayConnectionConfigTest.java
index 18518aac7757..377f526a9825 100644
--- a/tests/vcn/java/android/net/vcn/VcnGatewayConnectionConfigTest.java
+++ b/tests/vcn/java/android/net/vcn/VcnGatewayConnectionConfigTest.java
@@ -17,6 +17,8 @@
 package android.net.vcn;
 
 import static android.net.ipsec.ike.IkeSessionParams.IKE_OPTION_MOBIKE;
+import static android.net.vcn.VcnGatewayConnectionConfig.DEFAULT_UNDERLYING_NETWORK_PRIORITIES;
+import static android.net.vcn.VcnGatewayConnectionConfig.UNDERLYING_NETWORK_PRIORITIES_KEY;
 
 import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
@@ -30,6 +32,7 @@ import android.net.ipsec.ike.IkeSessionParams;
 import android.net.ipsec.ike.IkeTunnelConnectionParams;
 import android.net.vcn.persistablebundleutils.IkeSessionParamsUtilsTest;
 import android.net.vcn.persistablebundleutils.TunnelConnectionParamsUtilsTest;
+import android.os.PersistableBundle;
 
 import androidx.test.filters.SmallTest;
 import androidx.test.runner.AndroidJUnit4;
@@ -230,6 +233,16 @@ public class VcnGatewayConnectionConfigTest {
         assertEquals(config, new VcnGatewayConnectionConfig(config.toPersistableBundle()));
     }
 
+    @Test
+    public void testParsePersistableBundleWithoutVcnUnderlyingNetworkPriorities() {
+        PersistableBundle configBundle = buildTestConfig().toPersistableBundle();
+        configBundle.putPersistableBundle(UNDERLYING_NETWORK_PRIORITIES_KEY, null);
+
+        final VcnGatewayConnectionConfig config = new VcnGatewayConnectionConfig(configBundle);
+        assertEquals(
+                DEFAULT_UNDERLYING_NETWORK_PRIORITIES, config.getVcnUnderlyingNetworkPriorities());
+    }
+
     private static IkeTunnelConnectionParams buildTunnelConnectionParams(String ikePsk) {
         final IkeSessionParams ikeParams =
                 IkeSessionParamsUtilsTest.createBuilderMinimum()