diff mbox series

[RFC,v4,04/17] af_vsock: implement SEQPACKET receive loop

Message ID 20210207151526.804741-1-arseny.krasnov@kaspersky.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series virtio/vsock: introduce SOCK_SEQPACKET support | expand

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Context Check Description
netdev/cover_letter success Link
netdev/fixes_present success Link
netdev/patch_count fail Series longer than 15 patches
netdev/tree_selection success Guessed tree name to be net-next
netdev/subject_prefix success Link
netdev/cc_maintainers success CCed 8 of 8 maintainers
netdev/source_inline success Was 0 now: 0
netdev/verify_signedoff success Link
netdev/module_param success Was 0 now: 0
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/verify_fixes success Link
netdev/checkpatch warning CHECK: Alignment should match open parenthesis WARNING: function definition argument 'struct msghdr *' should also have an identifier name WARNING: function definition argument 'struct vsock_sock *' should also have an identifier name
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/header_inline success Link
netdev/stable success Stable not CCed

Commit Message

Arseny Krasnov Feb. 7, 2021, 3:15 p.m. UTC 
This adds receive loop for SEQPACKET. It looks like receive loop for
STREAM, but there is a little bit difference:
1) It doesn't call notify callbacks.
2) It doesn't care about 'SO_SNDLOWAT' and 'SO_RCVLOWAT' values, because
   there is no sense for these values in SEQPACKET case.
3) It waits until whole record is received or error is found during
   receiving.
4) It processes and sets 'MSG_TRUNC' flag.

So to avoid extra conditions for two types of socket inside one loop, two
independent functions were created.

Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
---
 include/net/af_vsock.h   |  5 +++
 net/vmw_vsock/af_vsock.c | 96 +++++++++++++++++++++++++++++++++++++++-
 2 files changed, 100 insertions(+), 1 deletion(-)

Comments

Stefano Garzarella Feb. 11, 2021, 11:47 a.m. UTC | #1 
On Sun, Feb 07, 2021 at 06:15:22PM +0300, Arseny Krasnov wrote:
>This adds receive loop for SEQPACKET. It looks like receive loop for
>STREAM, but there is a little bit difference:
>1) It doesn't call notify callbacks.
>2) It doesn't care about 'SO_SNDLOWAT' and 'SO_RCVLOWAT' values, because
>   there is no sense for these values in SEQPACKET case.
>3) It waits until whole record is received or error is found during
>   receiving.
>4) It processes and sets 'MSG_TRUNC' flag.
>
>So to avoid extra conditions for two types of socket inside one loop, two
>independent functions were created.
>
>Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
>---
> include/net/af_vsock.h   |  5 +++
> net/vmw_vsock/af_vsock.c | 96 +++++++++++++++++++++++++++++++++++++++-
> 2 files changed, 100 insertions(+), 1 deletion(-)
>
>diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
>index b1c717286993..bb6a0e52be86 100644
>--- a/include/net/af_vsock.h
>+++ b/include/net/af_vsock.h
>@@ -135,6 +135,11 @@ struct vsock_transport {
> 	bool (*stream_is_active)(struct vsock_sock *);
> 	bool (*stream_allow)(u32 cid, u32 port);
>
>+	/* SEQ_PACKET. */
>+	size_t (*seqpacket_seq_get_len)(struct vsock_sock *);
>+	int (*seqpacket_dequeue)(struct vsock_sock *, struct msghdr *,
>+				     int flags, bool *msg_ready);

CHECK: Alignment should match open parenthesis
#35: FILE: include/net/af_vsock.h:141:
+	int (*seqpacket_dequeue)(struct vsock_sock *, struct msghdr *,
+				     int flags, bool *msg_ready);

And to make checkpatch.pl happy please use the identifier name also for 
the others parameter. I know we haven't done this before, but for new 
code I think we can do it.

>+
> 	/* Notification. */
> 	int (*notify_poll_in)(struct vsock_sock *, size_t, bool *);
> 	int (*notify_poll_out)(struct vsock_sock *, size_t, bool *);
>diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
>index 66c8a932f49b..3d8af987216a 100644
>--- a/net/vmw_vsock/af_vsock.c
>+++ b/net/vmw_vsock/af_vsock.c
>@@ -1977,6 +1977,97 @@ static int __vsock_stream_recvmsg(struct sock *sk, struct msghdr *msg,
> 	return err;
> }
>
>+static int __vsock_seqpacket_recvmsg(struct sock *sk, struct msghdr *msg,
>+				     size_t len, int flags)
>+{
>+	const struct vsock_transport *transport;
>+	const struct iovec *orig_iov;
>+	unsigned long orig_nr_segs;
>+	bool msg_ready;
>+	struct vsock_sock *vsk;
>+	size_t record_len;
>+	long timeout;
>+	int err = 0;
>+	DEFINE_WAIT(wait);
>+
>+	vsk = vsock_sk(sk);
>+	transport = vsk->transport;
>+
>+	timeout = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
>+	orig_nr_segs = msg->msg_iter.nr_segs;
>+	orig_iov = msg->msg_iter.iov;
>+	msg_ready = false;
>+	record_len = 0;
>+
>+	while (1) {
>+		err = vsock_wait_data(sk, &wait, timeout, NULL, 0);
>+
>+		if (err <= 0) {
>+			/* In case of any loop break(timeout, signal
>+			 * interrupt or shutdown), we report user that
>+			 * nothing was copied.
>+			 */
>+			err = 0;
>+			break;
>+		}
>+
>+		if (record_len == 0) {
>+			record_len =
>+				transport->seqpacket_seq_get_len(vsk);
>+
>+			if (record_len == 0)
>+				continue;
>+		}
>+
>+		err = transport->seqpacket_dequeue(vsk, msg,
>+					flags, &msg_ready);

A single line here should be okay.

>+		if (err < 0) {
>+			if (err == -EAGAIN) {
>+				iov_iter_init(&msg->msg_iter, READ,
>+					      orig_iov, orig_nr_segs,
>+					      len);
>+				/* Clear 'MSG_EOR' here, because dequeue
>+				 * callback above set it again if it was
>+				 * set by sender. This 'MSG_EOR' is from
>+				 * dropped record.
>+				 */
>+				msg->msg_flags &= ~MSG_EOR;
>+				record_len = 0;
>+				continue;
>+			}
>+
>+			err = -ENOMEM;
>+			break;
>+		}
>+
>+		if (msg_ready)
>+			break;
>+	}
>+
>+	if (sk->sk_err)
>+		err = -sk->sk_err;
>+	else if (sk->sk_shutdown & RCV_SHUTDOWN)
>+		err = 0;
>+
>+	if (msg_ready) {
>+		/* User sets MSG_TRUNC, so return real length of
>+		 * packet.
>+		 */
>+		if (flags & MSG_TRUNC)
>+			err = record_len;
>+		else
>+			err = len - msg->msg_iter.count;
>+
>+		/* Always set MSG_TRUNC if real length of packet is
>+		 * bigger than user's buffer.
>+		 */
>+		if (record_len > len)
>+			msg->msg_flags |= MSG_TRUNC;
>+	}
>+
>+	return err;
>+}
>+
> static int
> vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
> 			  int flags)
>@@ -2032,7 +2123,10 @@ vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
> 		goto out;
> 	}
>
>-	err = __vsock_stream_recvmsg(sk, msg, len, flags);
>+	if (sk->sk_type == SOCK_STREAM)
>+		err = __vsock_stream_recvmsg(sk, msg, len, flags);
>+	else
>+		err = __vsock_seqpacket_recvmsg(sk, msg, len, flags);
>
> out:
> 	release_sock(sk);

The rest seems ok to me, but I need to get more familiar with SEQPACKET 
before giving my R-b.

Thanks,
Stefano
diff mbox series

Patch

diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
index b1c717286993..bb6a0e52be86 100644
--- a/include/net/af_vsock.h
+++ b/include/net/af_vsock.h
@@ -135,6 +135,11 @@  struct vsock_transport {
 	bool (*stream_is_active)(struct vsock_sock *);
 	bool (*stream_allow)(u32 cid, u32 port);
 
+	/* SEQ_PACKET. */
+	size_t (*seqpacket_seq_get_len)(struct vsock_sock *);
+	int (*seqpacket_dequeue)(struct vsock_sock *, struct msghdr *,
+				     int flags, bool *msg_ready);
+
 	/* Notification. */
 	int (*notify_poll_in)(struct vsock_sock *, size_t, bool *);
 	int (*notify_poll_out)(struct vsock_sock *, size_t, bool *);
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 66c8a932f49b..3d8af987216a 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -1977,6 +1977,97 @@  static int __vsock_stream_recvmsg(struct sock *sk, struct msghdr *msg,
 	return err;
 }
 
+static int __vsock_seqpacket_recvmsg(struct sock *sk, struct msghdr *msg,
+				     size_t len, int flags)
+{
+	const struct vsock_transport *transport;
+	const struct iovec *orig_iov;
+	unsigned long orig_nr_segs;
+	bool msg_ready;
+	struct vsock_sock *vsk;
+	size_t record_len;
+	long timeout;
+	int err = 0;
+	DEFINE_WAIT(wait);
+
+	vsk = vsock_sk(sk);
+	transport = vsk->transport;
+
+	timeout = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
+	orig_nr_segs = msg->msg_iter.nr_segs;
+	orig_iov = msg->msg_iter.iov;
+	msg_ready = false;
+	record_len = 0;
+
+	while (1) {
+		err = vsock_wait_data(sk, &wait, timeout, NULL, 0);
+
+		if (err <= 0) {
+			/* In case of any loop break(timeout, signal
+			 * interrupt or shutdown), we report user that
+			 * nothing was copied.
+			 */
+			err = 0;
+			break;
+		}
+
+		if (record_len == 0) {
+			record_len =
+				transport->seqpacket_seq_get_len(vsk);
+
+			if (record_len == 0)
+				continue;
+		}
+
+		err = transport->seqpacket_dequeue(vsk, msg,
+					flags, &msg_ready);
+		if (err < 0) {
+			if (err == -EAGAIN) {
+				iov_iter_init(&msg->msg_iter, READ,
+					      orig_iov, orig_nr_segs,
+					      len);
+				/* Clear 'MSG_EOR' here, because dequeue
+				 * callback above set it again if it was
+				 * set by sender. This 'MSG_EOR' is from
+				 * dropped record.
+				 */
+				msg->msg_flags &= ~MSG_EOR;
+				record_len = 0;
+				continue;
+			}
+
+			err = -ENOMEM;
+			break;
+		}
+
+		if (msg_ready)
+			break;
+	}
+
+	if (sk->sk_err)
+		err = -sk->sk_err;
+	else if (sk->sk_shutdown & RCV_SHUTDOWN)
+		err = 0;
+
+	if (msg_ready) {
+		/* User sets MSG_TRUNC, so return real length of
+		 * packet.
+		 */
+		if (flags & MSG_TRUNC)
+			err = record_len;
+		else
+			err = len - msg->msg_iter.count;
+
+		/* Always set MSG_TRUNC if real length of packet is
+		 * bigger than user's buffer.
+		 */
+		if (record_len > len)
+			msg->msg_flags |= MSG_TRUNC;
+	}
+
+	return err;
+}
+
 static int
 vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
 			  int flags)
@@ -2032,7 +2123,10 @@  vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
 		goto out;
 	}
 
-	err = __vsock_stream_recvmsg(sk, msg, len, flags);
+	if (sk->sk_type == SOCK_STREAM)
+		err = __vsock_stream_recvmsg(sk, msg, len, flags);
+	else
+		err = __vsock_seqpacket_recvmsg(sk, msg, len, flags);
 
 out:
 	release_sock(sk);