Only apply VPN isolation if it's fully routed

VPN is considered fully routed if both IPv4 and IPv6 have
either a default route or a prohibit route.

Bug: 145332510
Test: atest FrameworksNetTests
Change-Id: I59cf48552bca98092d1212e3d718fd420add5458

1 files changed, 26 insertions, 0 deletions

diff --git a/core/java/android/net/RouteInfo.java b/core/java/android/net/RouteInfo.java
index dbdaa4c2da67..e550f85e6b9a 100644
--- a/core/java/android/net/RouteInfo.java
+++ b/core/java/android/net/RouteInfo.java
@@ -426,6 +426,16 @@ public final class RouteInfo implements Parcelable {
     }
 
     /**
+     * Indicates if this route is an unreachable default route.
+     *
+     * @return {@code true} if it's an unreachable route with prefix length of 0.
+     * @hide
+     */
+    private boolean isUnreachableDefaultRoute() {
+        return mType == RTN_UNREACHABLE && mDestination.getPrefixLength() == 0;
+    }
+
+    /**
      * Indicates if this route is an IPv4 default route.
      * @hide
      */
@@ -434,6 +444,14 @@ public final class RouteInfo implements Parcelable {
     }
 
     /**
+     * Indicates if this route is an IPv4 unreachable default route.
+     * @hide
+     */
+    public boolean isIPv4UnreachableDefault() {
+        return isUnreachableDefaultRoute() && mDestination.getAddress() instanceof Inet4Address;
+    }
+
+    /**
      * Indicates if this route is an IPv6 default route.
      * @hide
      */
@@ -442,6 +460,14 @@ public final class RouteInfo implements Parcelable {
     }
 
     /**
+     * Indicates if this route is an IPv6 unreachable default route.
+     * @hide
+     */
+    public boolean isIPv6UnreachableDefault() {
+        return isUnreachableDefaultRoute() && mDestination.getAddress() instanceof Inet6Address;
+    }
+
+    /**
      * Indicates if this route is a host route (ie, matches only a single host address).
      *
      * @return {@code true} if the destination has a prefix length of 32 or 128 for IPv4 or IPv6,