+struct OVS_LOCKABLE rule_dpif;
+struct OVS_LOCKABLE group_dpif;
+
+/* Number of implemented OpenFlow tables. */
+enum { N_TABLES = 255 };
+enum { TBL_INTERNAL = N_TABLES - 1 }; /* Used for internal hidden rules. */
+BUILD_ASSERT_DECL(N_TABLES >= 2 && N_TABLES <= 255);
+
+/* Ofproto-dpif -- DPIF based ofproto implementation.
+ *
+ * Ofproto-dpif provides an ofproto implementation for those platforms which
+ * implement the netdev and dpif interface defined in netdev.h and dpif.h. The
+ * most important of which is the Linux Kernel Module (dpif-linux), but
+ * alternatives are supported such as a userspace only implementation
+ * (dpif-netdev), and a dummy implementation used for unit testing.
+ *
+ * Ofproto-dpif is divided into three major chunks.
+ *
+ * - ofproto-dpif.c
+ * The main ofproto-dpif module is responsible for implementing the
+ * provider interface, installing and removing datapath flows, maintaining
+ * packet statistics, running protocols (BFD, LACP, STP, etc), and
+ * configuring relevant submodules.
+ *
+ * - ofproto-dpif-upcall.c
+ * Ofproto-dpif-upcall is responsible for retrieving upcalls from the kernel,
+ * processing miss upcalls, and handing more complex ones up to the main
+ * ofproto-dpif module. Miss upcall processing boils down to figuring out
+ * what each packet's actions are, executing them (i.e. asking the kernel to
+ * forward it), and handing it up to ofproto-dpif to decided whether or not
+ * to install a kernel flow.
+ *
+ * - ofproto-dpif-xlate.c
+ * Ofproto-dpif-xlate is responsible for translating OpenFlow actions into
+ * datapath actions. */
+
+/* Stores the various features which the corresponding backer supports. */
+struct dpif_backer_support {
+ /* True if the datapath supports variable-length
+ * OVS_USERSPACE_ATTR_USERDATA in OVS_ACTION_ATTR_USERSPACE actions.
+ * False if the datapath supports only 8-byte (or shorter) userdata. */
+ bool variable_length_userdata;
+
+ /* True if the datapath supports masked data in OVS_ACTION_ATTR_SET
+ * actions. */
+ bool masked_set_action;
+
+ /* True if the datapath supports tnl_push and pop actions. */
+ bool tnl_push_pop;