diff --git a/net/sctp/socket.c b/net/sctp/socket.c index 6766913a53e626279a7a2f4eb543e1f9fa7b5263..08c6238802de1fad5b81d1e7943ebc61c7430952 100644 --- 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; }