--- openflow-2011-10-13-4.h	2015-07-23 09:54:16.732479345 -0700
+++ openflow-2011-10-12-5.h	2015-07-23 09:54:16.736479345 -0700
@@ -832,10 +832,20 @@
     OFPAT_EXPERIMENTER = 0xffff
 };
 
+enum ofp_controller_max_len {
+	OFPCML_MAX       = 0xffe5, /* maximum max_len value which can be used
+	                              to request a specific byte length. */
+	OFPCML_NO_BUFFER = 0xffff  /* indicates that no buffering should be
+	                              applied and the whole packet is to be
+	                              sent to the controller. */
+};
+
 /* Action structure for OFPAT_OUTPUT, which sends packets out 'port'.
  * When the 'port' is the OFPP_CONTROLLER, 'max_len' indicates the max
  * number of bytes to send.  A 'max_len' of zero means no bytes of the
- * packet should be sent.*/
+ * packet should be sent. A 'max_len' of OFPCML_NO_BUFFER means that
+ * the packet is not buffered and the complete packet is to be sent to
+ * the controller. */
 struct ofp_action_output {
     uint16_t type;                  /* OFPAT_OUTPUT. */
     uint16_t len;                   /* Length is 16. */