Add support for fwmark split tunneling

Packets are now only marked for fwmark if their destination is in one of
the routes for the target interface.

Change-Id: Ided4ad992c4cf957d77ae11fa62ac4843a8592c7
diff --git a/UidMarkMap.cpp b/UidMarkMap.cpp
index 34764cf..d30ac53 100644
--- a/UidMarkMap.cpp
+++ b/UidMarkMap.cpp
@@ -65,3 +65,15 @@
     }
     return -1;
 };
+
+bool UidMarkMap::anyRulesForMark(int mark) {
+    android::RWLock::AutoRLock lock(mRWLock);
+    android::netd::List<UidMarkEntry*>::iterator it;
+    for (it = mMap.begin(); it != mMap.end(); it++) {
+        UidMarkEntry *entry = *it;
+        if (entry->mark == mark) {
+            return true;
+        }
+    }
+    return false;
+}