+#define _ODPL_SFLOW_NR 2 /* sFlow samples. */
+#define ODPL_SFLOW (1 << _ODPL_SFLOW_NR)
+#define ODPL_ALL (ODPL_MISS | ODPL_ACTION | ODPL_SFLOW)
+
+/**
+ * struct odp_msg - format of messages read from datapath fd.
+ * @type: One of the %_ODPL_* constants.
+ * @length: Total length of message, including this header.
+ * @port: Port that received the packet embedded in this message.
+ * @reserved: Not currently used. Should be set to 0.
+ * @arg: Argument value whose meaning depends on @type.
+ *
+ * For @type == %_ODPL_MISS_NR, the header is followed by packet data. The
+ * @arg member is the ID (in network byte order) of the tunnel that
+ * encapsulated this packet. It is 0 if the packet was not received on a tunnel.
+ *
+ * For @type == %_ODPL_ACTION_NR, the header is followed by packet data. The
+ * @arg member is copied from the &struct odp_action_controller that caused
+ * the &struct odp_msg to be composed.
+ *
+ * For @type == %_ODPL_SFLOW_NR, the header is followed by &struct
+ * odp_sflow_sample_header, then by an array of &union odp_action (the number
+ * of which is specified in &struct odp_sflow_sample_header), then by packet
+ * data.
+ */