Wei Yongjun wrote:
> It should be possible to send a message and set the SCTP_EOF flag
> at the same time, but we don't support it yet. This patch fix the
> sendmsg() flag SCTP_EOF to comply to spec.
>
> Signed-off-by: Wei Yongjun <yjwei@xxxxxxxxxxxxxx>
> ---
> V1 -> V2:
> - SCTP_EOF cannot be set in CLOSED state
> - Forbid SCTP_EOF and send a message combination on non-blocking sockets
Hmm... I am going to have to think about this. I was hoping to resolve
the CLOSED state issue.
For non-blocking limitation, we should probably return EWOULDBLOCK since
there is really no way we can do this if the app decides to run this
in a loop, especially if the decide to do to the same destination.
The thing that's standing in our way of fixing the CLOSED state is the
SHUTDOWN_PENDING state. That's really not so much of a state as a modification
to any existing state that an association can be in.
I have a few ideas of how to solve that, but if you want to take a crack at
it, be my guest.
-vlad
> ---
> net/sctp/socket.c | 36 ++++++++++++++++++++++++++++++------
> 1 files changed, 30 insertions(+), 6 deletions(-)
>
> diff --git a/net/sctp/socket.c b/net/sctp/socket.c
> index 007e8ba..783d865 100644
> --- a/net/sctp/socket.c
> +++ b/net/sctp/socket.c
> @@ -1551,13 +1551,11 @@ SCTP_STATIC int sctp_sendmsg(struct kiocb *iocb, struct sock *sk,
> goto out_nounlock;
> }
>
> - /* If SCTP_EOF is set, no data can be sent. Disallow sending zero
> - * length messages when SCTP_EOF|SCTP_ABORT is not set.
> - * If SCTP_ABORT is set, the message length could be non zero with
> - * the msg_iov set to the user abort reason.
> + /* Disallow sending zero length messages when SCTP_EOF|SCTP_ABORT
> + * is not set. If SCTP_ABORT is set, the message length could be non
> + * zero with the msg_iov set to the user abort reason.
> */
> - if (((sinfo_flags & SCTP_EOF) && (msg_len > 0)) ||
> - (!(sinfo_flags & (SCTP_EOF|SCTP_ABORT)) && (msg_len == 0))) {
> + if (!(sinfo_flags & (SCTP_EOF|SCTP_ABORT)) && (msg_len == 0)) {
> err = -EINVAL;
> goto out_nounlock;
> }
> @@ -1615,6 +1613,26 @@ SCTP_STATIC int sctp_sendmsg(struct kiocb *iocb, struct sock *sk,
> }
>
> if (sinfo_flags & SCTP_EOF) {
> + /* SCTP_EOF cannot be set on an association
> + * in CLOSED state.
> + */
> + if (sctp_state(asoc, CLOSED)) {
> + err = -EINVAL;
> + goto out_nounlock;
> + }
> +
> + /*
> + * Forbid SCTP_EOF and send a message combination
> + * on non-blocking sockets.
> + */
> + if (msg_len != 0 && sk->sk_socket->file &&
> + sk->sk_socket->file->f_flags & O_NONBLOCK) {
> + err = -EINVAL;
> + goto out_nounlock;
> + }
> + }
> +
> + if (sinfo_flags & SCTP_EOF && msg_len == 0) {
> SCTP_DEBUG_PRINTK("Shutting down association: %p\n",
> asoc);
> sctp_primitive_SHUTDOWN(asoc, NULL);
> @@ -1846,6 +1864,12 @@ SCTP_STATIC int sctp_sendmsg(struct kiocb *iocb, struct sock *sk,
> else
> err = msg_len;
>
> + if (sinfo_flags & SCTP_EOF) {
> + SCTP_DEBUG_PRINTK("Shutting down association: %p\n",
> + asoc);
> + sctp_primitive_SHUTDOWN(asoc, NULL);
> + }
> +
> /* If we are already past ASSOCIATE, the lower
> * layers are responsible for association cleanup.
> */
--
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