+/* This function determines and sends the vacancy event, based on the value
+ * of current vacancy and threshold vacancy. If the current vacancy is less
+ * than or equal to vacancy_down, vacancy up events must be enabled, and when
+ * the current vacancy is greater or equal to vacancy_up, vacancy down events
+ * must be enabled. */
+static void
+send_table_status(struct ofproto *ofproto, uint8_t table_id)
+{
+ struct oftable *t = &ofproto->tables[table_id];
+ if (!t->vacancy_event) {
+ return;
+ }
+
+ uint8_t vacancy = oftable_vacancy(t);
+ enum ofp14_table_reason event;
+ if (vacancy < t->vacancy_down) {
+ event = OFPTR_VACANCY_DOWN;
+ } else if (vacancy > t->vacancy_up) {
+ event = OFPTR_VACANCY_UP;
+ } else {
+ return;
+ }
+
+ if (event == t->vacancy_event) {
+ struct ofputil_table_desc td;
+ query_table_desc__(&td, ofproto, table_id);
+ connmgr_send_table_status(ofproto->connmgr, &td, event);
+
+ t->vacancy_event = (event == OFPTR_VACANCY_DOWN
+ ? OFPTR_VACANCY_UP
+ : OFPTR_VACANCY_DOWN);
+ }
+}
+