[PATCH net] sctp: allow receiving msg when TCP-style sk is in CLOSED state

[PATCH net] sctp: allow receiving msg when TCP-style sk is in CLOSED state

[Xin Long]

Commit 141ddefce7c8 ("sctp: change sk state to CLOSED instead of
CLOSING in sctp_sock_migrate") changed sk state to CLOSED if the
assoc is closed when sctp_accept clones a new sk.

If there is still data in sk receive queue, users will not be able
to read it any more, as sctp_recvmsg returns directly if sk state
is CLOSED.

This patch is to add CLOSED state check in sctp_recvmsg to allow
reading data from TCP-style sk with CLOSED state as what TCP does.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
---
 net/sctp/socket.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 8812e1b..9fc417a 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -2079,7 +2079,7 @@ static int sctp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 	lock_sock(sk);
 
 	if (sctp_style(sk, TCP) && !sctp_sstate(sk, ESTABLISHED) &&
-	    !sctp_sstate(sk, CLOSING)) {
+	    !sctp_sstate(sk, CLOSING) && !sctp_sstate(sk, CLOSED)) {
 		err = -ENOTCONN;
 		goto out;
 	}
-- 
2.1.0

Re: [PATCH net] sctp: allow receiving msg when TCP-style sk is in CLOSED state

[Marcelo Ricardo Leitner]

On Sat, Jul 30, 2016 at 02:14:41PM +0800, Xin Long wrote:
> Commit 141ddefce7c8 ("sctp: change sk state to CLOSED instead of
> CLOSING in sctp_sock_migrate") changed sk state to CLOSED if the
> assoc is closed when sctp_accept clones a new sk.
> 
> If there is still data in sk receive queue, users will not be able
> to read it any more, as sctp_recvmsg returns directly if sk state
> is CLOSED.
> 
> This patch is to add CLOSED state check in sctp_recvmsg to allow
> reading data from TCP-style sk with CLOSED state as what TCP does.
> 
> Signed-off-by: Xin Long <lucien.xin@gmail.com>

So scripts can track this later more easily,

Fixes: 141ddefce7c8 ("sctp: change sk state to CLOSED instead of CLOSING in sctp_sock_migrate")
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>

> ---
>  net/sctp/socket.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/net/sctp/socket.c b/net/sctp/socket.c
> index 8812e1b..9fc417a 100644
> --- a/net/sctp/socket.c
> +++ b/net/sctp/socket.c
> @@ -2079,7 +2079,7 @@ static int sctp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
>  	lock_sock(sk);
>  
>  	if (sctp_style(sk, TCP) && !sctp_sstate(sk, ESTABLISHED) &&
> -	    !sctp_sstate(sk, CLOSING)) {
> +	    !sctp_sstate(sk, CLOSING) && !sctp_sstate(sk, CLOSED)) {
>  		err = -ENOTCONN;
>  		goto out;
>  	}
> -- 
> 2.1.0
> 
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Re: [PATCH net] sctp: allow receiving msg when TCP-style sk is in CLOSED state

[David Miller]

From: Xin Long <lucien.xin@gmail.com>
Date: Sat, 30 Jul 2016 14:14:41 +0800

> Commit 141ddefce7c8 ("sctp: change sk state to CLOSED instead of
> CLOSING in sctp_sock_migrate") changed sk state to CLOSED if the
> assoc is closed when sctp_accept clones a new sk.
> 
> If there is still data in sk receive queue, users will not be able
> to read it any more, as sctp_recvmsg returns directly if sk state
> is CLOSED.
> 
> This patch is to add CLOSED state check in sctp_recvmsg to allow
> reading data from TCP-style sk with CLOSED state as what TCP does.
> 
> Signed-off-by: Xin Long <lucien.xin@gmail.com>

Applied.