On Fri, Jun 03, 2016 at 10:42:45PM +0800, Xin Long wrote:
> Now sctp doesn't change socket state upon shutdown reception. It changes
> just the assoc state, even though it's a TCP-style socket.
>
> For some cases, if we really need to check sk->sk_state, it's necessary to
> fix this issue, at least when we use ss or netstat to dump, we can get a
> more exact information.
>
> As an improvement, we will change sk->sk_state when we change asoc->state
> to SHUTDOWN_RECEIVED, and also do it in sctp_shutdown to keep consistent with
> sctp_close.
>
> Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
> ---
> net/sctp/sm_sideeffect.c | 4 +++-
> net/sctp/socket.c | 1 +
> 2 files changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
> index aa37122..12d4519 100644
> --- a/net/sctp/sm_sideeffect.c
> +++ b/net/sctp/sm_sideeffect.c
> @@ -806,8 +806,10 @@ static void sctp_cmd_new_state(sctp_cmd_seq_t *cmds,
>
> /* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */
> if (sctp_state(asoc, SHUTDOWN_RECEIVED) &&
> - sctp_sstate(sk, ESTABLISHED))
> + sctp_sstate(sk, ESTABLISHED)) {
> + sk->sk_state = SCTP_SS_CLOSING;
> sk->sk_shutdown |= RCV_SHUTDOWN;
> + }
> }
>
> if (sctp_state(asoc, COOKIE_WAIT)) {
> diff --git a/net/sctp/socket.c b/net/sctp/socket.c
> index 67154b8..91a460d 100644
> --- a/net/sctp/socket.c
> +++ b/net/sctp/socket.c
> @@ -4193,6 +4193,7 @@ static void sctp_shutdown(struct sock *sk, int how)
> return;
>
> if (how & SEND_SHUTDOWN) {
> + sk->sk_state = SCTP_SS_CLOSING;
> ep = sctp_sk(sk)->ep;
> if (!list_empty(&ep->asocs)) {
> asoc = list_entry(ep->asocs.next,
Oh but I think the removed chunk was important, it just needed fixing.
A comment in there said:
/* If the association on the newsk is already closed before
* accept() is called, set RCV_SHUTDOWN flag.
*/
Meaning that there is a way that it will create a socket in the state
you're trying to avoid here, which now is not handled.
Marcelo
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