diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 7f59ee9..46a85c9 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -238,6 +238,11 @@
 	u32	end_seq;
 };
 
+/*These are used to set the sack_ok field in struct tcp_options_received */
+#define TCP_SACK_SEEN     (1 << 0)   /*1 = peer is SACK capable, */
+#define TCP_FACK_ENABLED  (1 << 1)   /*1 = FACK is enabled locally*/
+#define TCP_DSACK_SEEN    (1 << 2)   /*1 = DSACK was received from peer*/
+
 struct tcp_options_received {
 /*	PAWS/RTTM data	*/
 	long	ts_recent_stamp;/* Time we stored ts_recent (for aging) */