sctp: Bring SCTP_DELAYED_ACK socket option into API compliance

Brings delayed_ack socket option set/get into line with the latest ietf
socket extensions API draft, while maintaining backwards compatibility.

Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 0ce0443..e111517 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -300,6 +300,7 @@
 
 	/* The default SACK delay timeout for new associations. */
 	__u32 sackdelay;
+	__u32 sackfreq;
 
 	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
 	__u32 param_flags;
@@ -938,6 +939,7 @@
 
 	/* SACK delay timeout */
 	unsigned long sackdelay;
+	__u32 sackfreq;
 
 	/* When was the last time (in jiffies) that we heard from this
 	 * transport?  We use this to pick new active and retran paths.
@@ -1542,6 +1544,7 @@
 		 *             : SACK's are not delayed (see Section 6).
 		 */
 		__u8    sack_needed;     /* Do we need to sack the peer? */
+		__u32	sack_cnt;
 
 		/* These are capabilities which our peer advertised.  */
 		__u8	ecn_capable;	 /* Can peer do ECN? */
@@ -1651,6 +1654,7 @@
 
 	/* SACK delay timeout */
 	unsigned long sackdelay;
+	__u32 sackfreq;
 
 
 	unsigned long timeouts[SCTP_NUM_TIMEOUT_TYPES];