sctp: fix the sendmsg() flag SCTP_EOF to comply to spec

PATCH Superseded Wei Yongjun 2 participants 2 messages Apr 19, 2010 – Apr 20, 2010

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Networking SCTP protocol

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Wei Yongjun

author

2010-04-19 08:30 UTC #0 lore raw

PATCH v2 1/1 sctp: fix the sendmsg() flag SCTP_EOF to comply to spec

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 <[email protected]>

---
V1 -> V2:
- SCTP_EOF cannot be set in CLOSED state
- Forbid SCTP_EOF and send a message combination on non-blocking sockets

---
 net/sctp/socket.c |   36 ++++++++++++++++++++++++++++++------
 1 files changed, 30 insertions(+), 6 deletions(-)

net/sctp/socket.c +30 -6

index 007e8ba..783d865 100644
@@ -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.
 	 */

Signature · 1 line

1.6.5.2

Vlad Yasevich

2010-04-20 13:43 UTC #1 lore raw

Re: [PATCH v2] sctp: fix the sendmsg() flag SCTP_EOF to comply to

Quoted 9 lines · Wei Yongjun

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 <[email protected]>
---
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

Quoted 66 lines

---
 net/sctp/socket.c |   36 ++++++++++++++++++++++++++++++------
 1 files changed, 30 insertions(+), 6 deletions(-)

net/sctp/socket.c +30 -6

index 007e8ba..783d865 100644
@@ -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.
 	 */