Support connecting to networks with misconfigured subnet masks.

In K and earlier, we would connect to a network where the gateway
was not covered by the subnet mask of the IP address. This is an
invalid configuration, but it used to work, and other OSes appear
to accept it too, so support it.

Bug: 19067207

(cherry picked from commit 2dfb79a54adeb4bcf1f62332a9db467fce302ced)

Change-Id: I80088f291466dbd5a47f360dcc1620acee5cf57e
diff --git a/core/java/android/net/StaticIpConfiguration.java b/core/java/android/net/StaticIpConfiguration.java
index 5a273cf..8bf8f2e 100644
--- a/core/java/android/net/StaticIpConfiguration.java
+++ b/core/java/android/net/StaticIpConfiguration.java
@@ -76,15 +76,22 @@
 
     /**
      * Returns the network routes specified by this object. Will typically include a
-     * directly-connected route for the IP address's local subnet and a default route.
+     * directly-connected route for the IP address's local subnet and a default route. If the
+     * default gateway is not covered by the directly-connected route, it will also contain a host
+     * route to the gateway as well. This configuration is arguably invalid, but it used to work
+     * in K and earlier, and other OSes appear to accept it.
      */
     public List<RouteInfo> getRoutes(String iface) {
-        List<RouteInfo> routes = new ArrayList<RouteInfo>(2);
+        List<RouteInfo> routes = new ArrayList<RouteInfo>(3);
         if (ipAddress != null) {
-            routes.add(new RouteInfo(ipAddress, null, iface));
+            RouteInfo connectedRoute = new RouteInfo(ipAddress, null, iface);
+            routes.add(connectedRoute);
+            if (gateway != null && !connectedRoute.matches(gateway)) {
+                routes.add(RouteInfo.makeHostRoute(gateway, iface));
+            }
         }
         if (gateway != null) {
-            routes.add(new RouteInfo((LinkAddress) null, gateway, iface));
+            routes.add(new RouteInfo((IpPrefix) null, gateway, iface));
         }
         return routes;
     }