sctp: add support for generating assoc reset event notification

This patch is to add Association Reset Event described in rfc6525
section 6.1.2.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sctp/ulpevent.c b/net/sctp/ulpevent.c
index c8881bc5..420d7f3 100644
--- a/net/sctp/ulpevent.c
+++ b/net/sctp/ulpevent.c
@@ -883,6 +883,34 @@
 	return event;
 }
 
+struct sctp_ulpevent *sctp_ulpevent_make_assoc_reset_event(
+	const struct sctp_association *asoc, __u16 flags, __u32 local_tsn,
+	__u32 remote_tsn, gfp_t gfp)
+{
+	struct sctp_assoc_reset_event *areset;
+	struct sctp_ulpevent *event;
+	struct sk_buff *skb;
+
+	event = sctp_ulpevent_new(sizeof(struct sctp_assoc_reset_event),
+				  MSG_NOTIFICATION, gfp);
+	if (!event)
+		return NULL;
+
+	skb = sctp_event2skb(event);
+	areset = (struct sctp_assoc_reset_event *)
+		skb_put(skb, sizeof(struct sctp_assoc_reset_event));
+
+	areset->assocreset_type = SCTP_ASSOC_RESET_EVENT;
+	areset->assocreset_flags = flags;
+	areset->assocreset_length = sizeof(struct sctp_assoc_reset_event);
+	sctp_ulpevent_set_owner(event, asoc);
+	areset->assocreset_assoc_id = sctp_assoc2id(asoc);
+	areset->assocreset_local_tsn = local_tsn;
+	areset->assocreset_remote_tsn = remote_tsn;
+
+	return event;
+}
+
 /* Return the notification type, assuming this is a notification
  * event.
  */