diff --git a/bridge/br_common.h b/bridge/br_common.h
index 718ecb9..83b2b9f 100644
--- a/bridge/br_common.h
+++ b/bridge/br_common.h

@@ -5,6 +5,7 @@ extern int print_fdb(const struct sockaddr_nl *who,
 		     struct nlmsghdr *n, void *arg);
 
 extern int do_fdb(int argc, char **argv);
+extern int do_mdb(int argc, char **argv);
 extern int do_monitor(int argc, char **argv);
 
 extern int preferred_family;

@@ -12,3 +13,37 @@ extern int show_stats;
 extern int show_detail;
 extern int timestamp;
 extern struct rtnl_handle rth;
+
+/* Bridge multicast database attributes
+ * [MDBA_MDB] = {
+ *    [MDBA_MCADDR]
+ *    [MDBA_BRPORT_NO]
+ * }
+ * [MDBA_ROUTER] = {
+ *    [MDBA_BRPORT_NO]
+ * }
+ */
+enum {
+	MDBA_UNSPEC,
+	MDBA_MDB,
+	MDBA_ROUTER,
+	__MDBA_MAX,
+};
+#define MDBA_MAX (__MDBA_MAX - 1)
+
+enum {
+	MDBA_MDB_UNSPEC,
+	MDBA_MCADDR,
+	MDBA_BRPORT_NO,
+	__MDBA_MDB_MAX,
+};
+#define MDBA_MDB_MAX (__MDBA_MDB_MAX - 1)
+
+struct br_port_msg {
+        int ifindex;
+};
+
+#ifndef MDBA_RTA
+#define MDBA_RTA(r) \
+	((struct rtattr*)(((char*)(r)) + NLMSG_ALIGN(sizeof(struct br_port_msg))))
+#endif