On Sat, Jul 30, 2016 at 02:09:09PM +0800, Xin Long wrote:
> Prior to this patch, once sctp received SHUTDOWN or shutdown with RD,
> sk->sk_shutdown would be set with RCV_SHUTDOWN, and all events would
> be dropped in sctp_ulpq_tail_event(). It would cause:
>
> 1. some notifications couldn't be received by users. like
> SCTP_SHUTDOWN_COMP generated by sctp_sf_do_4_C().
>
> 2. sctp would also never trigger sk_data_ready when the association
> was closed, making it harder to identify the end of the association
> by calling recvmsg() and getting an EOF. It was not convenient for
> kernel users.
>
> The check here should be stopping delivering DATA chunks after receiving
> SHUTDOWN, and stopping delivering ANY chunks after sctp_close().
>
> So this patch is to allow notifications to enqueue into receive queue
> even if sk->sk_shutdown is set to RCV_SHUTDOWN in sctp_ulpq_tail_event,
> but if sk->sk_shutdown == RCV_SHUTDOWN | SEND_SHUTDOWN, it drops all
> events.
>
> Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@xxxxxxxxx>
> ---
> net/sctp/ulpqueue.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/net/sctp/ulpqueue.c b/net/sctp/ulpqueue.c
> index ec166d2..877e550 100644
> --- a/net/sctp/ulpqueue.c
> +++ b/net/sctp/ulpqueue.c
> @@ -204,7 +204,9 @@ int sctp_ulpq_tail_event(struct sctp_ulpq *ulpq, struct sctp_ulpevent *event)
> /* If the socket is just going to throw this away, do not
> * even try to deliver it.
> */
> - if (sock_flag(sk, SOCK_DEAD) || (sk->sk_shutdown & RCV_SHUTDOWN))
> + if (sk->sk_shutdown & RCV_SHUTDOWN &&
> + (sk->sk_shutdown & SEND_SHUTDOWN ||
> + !sctp_ulpevent_is_notification(event)))
> goto out_free;
>
> if (!sctp_ulpevent_is_notification(event)) {
> --
> 2.1.0
>
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