Disable DAD for downstream interfaces when tethering

Bug: 30298058
Change-Id: If4cd1f2e2b782ff08d667eb065138c06559b3394
diff --git a/server/InterfaceController.h b/server/InterfaceController.h
index 356cc5a..98c8b8f 100644
--- a/server/InterfaceController.h
+++ b/server/InterfaceController.h
@@ -24,6 +24,7 @@
     static int setEnableIPv6(const char *interface, const int on);
     static int setAcceptIPv6Ra(const char *interface, const int on);
     static int setAcceptIPv6Dad(const char *interface, const int on);
+    static int setIPv6DadTransmits(const char *interface, const char *value);
     static int setIPv6PrivacyExtensions(const char *interface, const int on);
     static int setIPv6NdOffload(char* interface, const int on);
     static int setMtu(const char *interface, const char *mtu);