On 06/30/2011 09:31 AM, Thomas Graf wrote:
> On Wed, Jun 29, 2011 at 12:14:41PM -0400, Vladislav Yasevich wrote:
>> Right. The lack of ABORT from the receive of data is a bug. I was trying to point out
>> that instead of modified the sender of data to send the ABORT, you modify the receiver
>> to send the ABORT when it is being closed while having data queued.
>
> Is this what you had in mind?
Almost. It could really be a simple true/false condition about recvqueue or inqueue
being non-empty. If that's the case, trigger abort.
-vlad
>
> Trigger user ABORT when a socket is closed which has skbs sitting on
> the receive queue. If data was lost, there is no point in doing a
> graceful shutdown. This is consistent with TCP behaviour.
>
> This also resolves the situation when a receiver cannot reopen its rwnd
> and the sender continues retransmission attempts indefinitely before
> initiating the shutdown.
>
> Signed-off-by: Thomas Graf <tgraf@xxxxxxxxxxxxx>
>
> diff --git a/include/net/sctp/ulpevent.h b/include/net/sctp/ulpevent.h
> index 99b027b..ca4693b 100644
> --- a/include/net/sctp/ulpevent.h
> +++ b/include/net/sctp/ulpevent.h
> @@ -80,7 +80,7 @@ static inline struct sctp_ulpevent *sctp_skb2event(struct sk_buff *skb)
>
> void sctp_ulpevent_free(struct sctp_ulpevent *);
> int sctp_ulpevent_is_notification(const struct sctp_ulpevent *);
> -void sctp_queue_purge_ulpevents(struct sk_buff_head *list);
> +unsigned int sctp_queue_purge_ulpevents(struct sk_buff_head *list);
>
> struct sctp_ulpevent *sctp_ulpevent_make_assoc_change(
> const struct sctp_association *asoc,
> diff --git a/net/sctp/socket.c b/net/sctp/socket.c
> index 6766913..958253a 100644
> --- a/net/sctp/socket.c
> +++ b/net/sctp/socket.c
> @@ -1384,6 +1384,7 @@ SCTP_STATIC void sctp_close(struct sock *sk, long timeout)
> struct sctp_endpoint *ep;
> struct sctp_association *asoc;
> struct list_head *pos, *temp;
> + unsigned int data_was_unread;
>
> SCTP_DEBUG_PRINTK("sctp_close(sk: 0x%p, timeout:%ld)\n", sk, timeout);
>
> @@ -1393,6 +1394,10 @@ SCTP_STATIC void sctp_close(struct sock *sk, long timeout)
>
> ep = sctp_sk(sk)->ep;
>
> + /* Clean up any skbs sitting on the receive queue. */
> + data_was_unread = sctp_queue_purge_ulpevents(&sk->sk_receive_queue);
> + data_was_unread += sctp_queue_purge_ulpevents(&sctp_sk(sk)->pd_lobby);
> +
> /* Walk all associations on an endpoint. */
> list_for_each_safe(pos, temp, &ep->asocs) {
> asoc = list_entry(pos, struct sctp_association, asocs);
> @@ -1410,7 +1415,8 @@ SCTP_STATIC void sctp_close(struct sock *sk, long timeout)
> }
> }
>
> - if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
> + if (data_was_unread ||
> + (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime)) {
> struct sctp_chunk *chunk;
>
> chunk = sctp_make_abort_user(asoc, NULL, 0);
> @@ -1420,10 +1426,6 @@ SCTP_STATIC void sctp_close(struct sock *sk, long timeout)
> sctp_primitive_SHUTDOWN(asoc, NULL);
> }
>
> - /* Clean up any skbs sitting on the receive queue. */
> - sctp_queue_purge_ulpevents(&sk->sk_receive_queue);
> - sctp_queue_purge_ulpevents(&sctp_sk(sk)->pd_lobby);
> -
> /* On a TCP-style socket, block for at most linger_time if set. */
> if (sctp_style(sk, TCP) && timeout)
> sctp_wait_for_close(sk, timeout);
> diff --git a/net/sctp/ulpevent.c b/net/sctp/ulpevent.c
> index e70e5fc..aab3184 100644
> --- a/net/sctp/ulpevent.c
> +++ b/net/sctp/ulpevent.c
> @@ -1081,9 +1081,19 @@ void sctp_ulpevent_free(struct sctp_ulpevent *event)
> }
>
> /* Purge the skb lists holding ulpevents. */
> -void sctp_queue_purge_ulpevents(struct sk_buff_head *list)
> +unsigned int sctp_queue_purge_ulpevents(struct sk_buff_head *list)
> {
> struct sk_buff *skb;
> - while ((skb = skb_dequeue(list)) != NULL)
> + unsigned int data_unread = 0;
> +
> + while ((skb = skb_dequeue(list)) != NULL) {
> + struct sctp_ulpevent *event = sctp_skb2event(skb);
> +
> + if (!sctp_ulpevent_is_notification(event))
> + data_unread += skb->len;
> +
> sctp_ulpevent_free(sctp_skb2event(skb));
> + }
> +
> + return data_unread;
> }
>
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