When the controller wants to get statistics for aggregate or set of flow entries, it should send OFPMP_AGGREGATE multipart message (ofp_multipart_request) to switch.
The message format that should be used by controller for sending the multipart request message is defined in the Introduction section of this chapter.
For getting the statistics of a flow entry, the controller should set the type field as OFPMP_AGGREGATE.
The body field should be filled with the following structure:
/* Body for ofp_multipart_request of type OFPMP_AGGREGATE. */
struct ofp_aggregate_stats_request {
uint8_t table_id; /* ID of table to read (from
* ofp_table_stats) OFPTT_ALL for
* all tables. */
uint8_t pad[3]; /* Align to 32 bits. */
uint32_t out_port; /* Require matching entries to include this
* as an output port. A value of OFPP_ANY
...