-/* Does all of the periodic maintenance required by 'mgr'. Calls
- * 'handle_openflow' for each message received on an OpenFlow connection,
- * passing along the OpenFlow connection itself and the message that was sent.
- * The 'handle_openflow' callback must not free the message. */
+/* Does all of the periodic maintenance required by 'mgr'.
+ *
+ * If 'handle_openflow' is nonnull, calls 'handle_openflow' for each message
+ * received on an OpenFlow connection, passing along the OpenFlow connection
+ * itself and the message that was sent. If 'handle_openflow' returns true,
+ * the message is considered to be fully processed. If 'handle_openflow'
+ * returns false, the message is considered not to have been processed at all;
+ * it will be stored and re-presented to 'handle_openflow' following the next
+ * call to connmgr_retry(). 'handle_openflow' must not modify or free the
+ * message.
+ *
+ * If 'handle_openflow' is NULL, no OpenFlow messages will be processed and
+ * other activities that could affect the flow table (in-band processing,
+ * fail-open processing) are suppressed too. */