Update VPN isolation code for excluded routes

Bug: 230058738
Test: atest LinkPropertiesTest

Result: https://paste.googleplex.com/4706859672928256

Change-Id: I970fca6b0e2cd358e9bd77152563d13367867c74

framework/src/android/net/LinkProperties.java

@@ -1365,6 +1365,21 @@ public final class LinkProperties implements Parcelable {
         return false;
     }
 
+    /**
+     * Returns true if this link has a throw route.
+     *
+     * @return {@code true} if there is an exclude route, {@code false} otherwise.
+     * @hide
+     */
+    public boolean hasExcludeRoute() {
+        for (RouteInfo r : mRoutes) {
+            if (r.getType() == RouteInfo.RTN_THROW) {
+                return true;
+            }
+        }
+        return false;
+    }
+
     /**
      * Compares this {@code LinkProperties} interface name against the target
      *

service/src/com/android/server/ConnectivityService.java

@@ -8056,7 +8056,8 @@ public class ConnectivityService extends IConnectivityManager.Stub
                 && nc.getOwnerUid() != Process.SYSTEM_UID
                 && lp.getInterfaceName() != null
                 && (lp.hasIpv4DefaultRoute() || lp.hasIpv4UnreachableDefaultRoute())
-                && (lp.hasIpv6DefaultRoute() || lp.hasIpv6UnreachableDefaultRoute());
+                && (lp.hasIpv6DefaultRoute() || lp.hasIpv6UnreachableDefaultRoute())
+                && !lp.hasExcludeRoute();
     }
 
     private static UidRangeParcel[] toUidRangeStableParcels(final @NonNull Set<UidRange> ranges) {

tests/common/java/android/net/LinkPropertiesTest.java

@@ -1261,6 +1261,17 @@ public class LinkPropertiesTest {
         assertFalse(lp.hasIpv4UnreachableDefaultRoute());
     }
 
+    @Test @IgnoreUpTo(Build.VERSION_CODES.S_V2)
+    public void testHasExcludeRoute() {
+        LinkProperties lp = new LinkProperties();
+        lp.setInterfaceName("VPN");
+        lp.addRoute(new RouteInfo(new IpPrefix(ADDRV4, 2), RTN_UNICAST));
+        lp.addRoute(new RouteInfo(new IpPrefix(ADDRV6, 0), RTN_UNICAST));
+        assertFalse(lp.hasExcludeRoute());
+        lp.addRoute(new RouteInfo(new IpPrefix(ADDRV6, 2), RTN_THROW));
+        assertTrue(lp.hasExcludeRoute());
+    }
+
     @Test @IgnoreUpTo(Build.VERSION_CODES.Q)
     @EnableCompatChanges({LinkProperties.EXCLUDED_ROUTES})
     public void testRouteAddWithSameKey() throws Exception {