sctp: fix missing send up SCTP_SENDER_DRY_EVENT when subscribe it

We forgot to send up SCTP_SENDER_DRY_EVENT notification when user app subscribes to this event, and there is no data to be sent or retransmit. This is required by the Socket API and used by the DTLS/SCTP implementation. Reported-by: Michael Tüxen <[email protected]> Signed-off-by: Wei Yongjun <[email protected]> Tested-by: Robin Seggelmann <[email protected]> Signed-off-by: David S. Miller <[email protected]>
mna · Jul 7, 2011 · 9491230 · 9491230
1 parent f03d78d
commit 9491230
Showing 1 changed file with 23 additions and 0 deletions.
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
@@ -2073,10 +2073,33 @@ static int sctp_setsockopt_disable_fragments(struct sock *sk,
 static int sctp_setsockopt_events(struct sock *sk, char __user *optval,
 				  unsigned int optlen)
 {
+	struct sctp_association *asoc;
+	struct sctp_ulpevent *event;
+
 	if (optlen > sizeof(struct sctp_event_subscribe))
 		return -EINVAL;
 	if (copy_from_user(&sctp_sk(sk)->subscribe, optval, optlen))
 		return -EFAULT;
+
+	/*
+	 * At the time when a user app subscribes to SCTP_SENDER_DRY_EVENT,
+	 * if there is no data to be sent or retransmit, the stack will
+	 * immediately send up this notification.
+	 */
+	if (sctp_ulpevent_type_enabled(SCTP_SENDER_DRY_EVENT,
+				       &sctp_sk(sk)->subscribe)) {
+		asoc = sctp_id2assoc(sk, 0);
+
+		if (asoc && sctp_outq_is_empty(&asoc->outqueue)) {
+			event = sctp_ulpevent_make_sender_dry_event(asoc,
+					GFP_ATOMIC);
+			if (!event)
+				return -ENOMEM;
+
+			sctp_ulpq_tail_event(&asoc->ulpq, event);
+		}
+	}
+
 	return 0;
 }