+ /* Returns one greater than the largest port number accepted in flow
+ * actions. */
+ int (*get_max_ports)(const struct dpif *dpif);
+
+ /* Returns the Netlink PID value to supply in OVS_ACTION_ATTR_USERSPACE
+ * actions as the OVS_USERSPACE_ATTR_PID attribute's value, for use in
+ * flows whose packets arrived on port 'port_no'.
+ *
+ * A 'port_no' of UINT16_MAX should be treated as a special case. The
+ * implementation should return a reserved PID, not allocated to any port,
+ * that the client may use for special purposes.
+ *
+ * The return value only needs to be meaningful when DPIF_UC_ACTION has
+ * been enabled in the 'dpif''s listen mask, and it is allowed to change
+ * when DPIF_UC_ACTION is disabled and then re-enabled.
+ *
+ * A dpif provider that doesn't have meaningful Netlink PIDs can use NULL
+ * for this function. This is equivalent to always returning 0. */
+ uint32_t (*port_get_pid)(const struct dpif *dpif, uint16_t port_no);
+
+ /* Attempts to begin dumping the ports in a dpif. On success, returns 0
+ * and initializes '*statep' with any data needed for iteration. On
+ * failure, returns a positive errno value. */
+ int (*port_dump_start)(const struct dpif *dpif, void **statep);
+
+ /* Attempts to retrieve another port from 'dpif' for 'state', which was
+ * initialized by a successful call to the 'port_dump_start' function for
+ * 'dpif'. On success, stores a new dpif_port into 'port' and returns 0.
+ * Returns EOF if the end of the port table has been reached, or a positive
+ * errno value on error. This function will not be called again once it
+ * returns nonzero once for a given iteration (but the 'port_dump_done'
+ * function will be called afterward).
+ *
+ * The dpif provider retains ownership of the data stored in 'port'. It
+ * must remain valid until at least the next call to 'port_dump_next' or
+ * 'port_dump_done' for 'state'. */
+ int (*port_dump_next)(const struct dpif *dpif, void *state,
+ struct dpif_port *port);
+
+ /* Releases resources from 'dpif' for 'state', which was initialized by a
+ * successful call to the 'port_dump_start' function for 'dpif'. */
+ int (*port_dump_done)(const struct dpif *dpif, void *state);