diff mbox series

[RFC,v1,2/4] virtio/vsock: support MSG_PEEK for SOCK_SEQPACKET

Message ID 20230618062451.79980-3-AVKrasnov@sberdevices.ru
State New
Headers
Series virtio/vsock: some updates for MSG_PEEK flag |

Commit Message

Arseniy Krasnov June 18, 2023, 6:24 a.m. UTC 
  This adds support of MSG_PEEK flag for SOCK_SEQPACKET type of socket.
Difference with SOCK_STREAM is that this callback returns either length
of the message or error.

Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
---
 net/vmw_vsock/virtio_transport_common.c | 63 +++++++++++++++++++++++--
 1 file changed, 60 insertions(+), 3 deletions(-)

Comments

Stefano Garzarella June 26, 2023, 4:28 p.m. UTC | #1 
On Sun, Jun 18, 2023 at 09:24:49AM +0300, Arseniy Krasnov wrote:
>This adds support of MSG_PEEK flag for SOCK_SEQPACKET type of socket.
>Difference with SOCK_STREAM is that this callback returns either length
>of the message or error.
>
>Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
>---
> net/vmw_vsock/virtio_transport_common.c | 63 +++++++++++++++++++++++--
> 1 file changed, 60 insertions(+), 3 deletions(-)
>
>diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
>index 2ee40574c339..352d042b130b 100644
>--- a/net/vmw_vsock/virtio_transport_common.c
>+++ b/net/vmw_vsock/virtio_transport_common.c
>@@ -460,6 +460,63 @@ virtio_transport_stream_do_dequeue(struct vsock_sock *vsk,
> 	return err;
> }
>
>+static ssize_t
>+virtio_transport_seqpacket_do_peek(struct vsock_sock *vsk,
>+				   struct msghdr *msg)
>+{
>+	struct virtio_vsock_sock *vvs = vsk->trans;
>+	struct sk_buff *skb;
>+	size_t total, len;
>+
>+	spin_lock_bh(&vvs->rx_lock);
>+
>+	if (!vvs->msg_count) {
>+		spin_unlock_bh(&vvs->rx_lock);
>+		return 0;
>+	}
>+
>+	total = 0;
>+	len = msg_data_left(msg);
>+
>+	skb_queue_walk(&vvs->rx_queue, skb) {
>+		struct virtio_vsock_hdr *hdr;
>+
>+		if (total < len) {
>+			size_t bytes;
>+			int err;
>+
>+			bytes = len - total;
>+			if (bytes > skb->len)
>+				bytes = skb->len;
>+
>+			spin_unlock_bh(&vvs->rx_lock);
>+
>+			/* sk_lock is held by caller so no one else can dequeue.
>+			 * Unlock rx_lock since memcpy_to_msg() may sleep.
>+			 */
>+			err = memcpy_to_msg(msg, skb->data, bytes);
>+			if (err)
>+				return err;
>+
>+			spin_lock_bh(&vvs->rx_lock);
>+		}
>+
>+		total += skb->len;
>+		hdr = virtio_vsock_hdr(skb);
>+
>+		if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOM) {
>+			if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOR)
>+				msg->msg_flags |= MSG_EOR;
>+
>+			break;
>+		}
>+	}
>+
>+	spin_unlock_bh(&vvs->rx_lock);
>+
>+	return total;

Should we return the minimum between total and len?

Thanks,
Stefano

>+}
>+
> static int virtio_transport_seqpacket_do_dequeue(struct vsock_sock *vsk,
> 						 struct msghdr *msg,
> 						 int flags)
>@@ -554,9 +611,9 @@ virtio_transport_seqpacket_dequeue(struct vsock_sock *vsk,
> 				   int flags)
> {
> 	if (flags & MSG_PEEK)
>-		return -EOPNOTSUPP;
>-
>-	return virtio_transport_seqpacket_do_dequeue(vsk, msg, flags);
>+		return virtio_transport_seqpacket_do_peek(vsk, msg);
>+	else
>+		return virtio_transport_seqpacket_do_dequeue(vsk, msg, flags);
> }
> EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_dequeue);
>
>-- 
>2.25.1
>
Arseniy Krasnov June 27, 2023, 4:34 a.m. UTC | #2 
On 26.06.2023 19:28, Stefano Garzarella wrote:
> On Sun, Jun 18, 2023 at 09:24:49AM +0300, Arseniy Krasnov wrote:
>> This adds support of MSG_PEEK flag for SOCK_SEQPACKET type of socket.
>> Difference with SOCK_STREAM is that this callback returns either length
>> of the message or error.
>>
>> Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
>> ---
>> net/vmw_vsock/virtio_transport_common.c | 63 +++++++++++++++++++++++--
>> 1 file changed, 60 insertions(+), 3 deletions(-)
>>
>> diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
>> index 2ee40574c339..352d042b130b 100644
>> --- a/net/vmw_vsock/virtio_transport_common.c
>> +++ b/net/vmw_vsock/virtio_transport_common.c
>> @@ -460,6 +460,63 @@ virtio_transport_stream_do_dequeue(struct vsock_sock *vsk,
>>     return err;
>> }
>>
>> +static ssize_t
>> +virtio_transport_seqpacket_do_peek(struct vsock_sock *vsk,
>> +                   struct msghdr *msg)
>> +{
>> +    struct virtio_vsock_sock *vvs = vsk->trans;
>> +    struct sk_buff *skb;
>> +    size_t total, len;
>> +
>> +    spin_lock_bh(&vvs->rx_lock);
>> +
>> +    if (!vvs->msg_count) {
>> +        spin_unlock_bh(&vvs->rx_lock);
>> +        return 0;
>> +    }
>> +
>> +    total = 0;
>> +    len = msg_data_left(msg);
>> +
>> +    skb_queue_walk(&vvs->rx_queue, skb) {
>> +        struct virtio_vsock_hdr *hdr;
>> +
>> +        if (total < len) {
>> +            size_t bytes;
>> +            int err;
>> +
>> +            bytes = len - total;
>> +            if (bytes > skb->len)
>> +                bytes = skb->len;
>> +
>> +            spin_unlock_bh(&vvs->rx_lock);
>> +
>> +            /* sk_lock is held by caller so no one else can dequeue.
>> +             * Unlock rx_lock since memcpy_to_msg() may sleep.
>> +             */
>> +            err = memcpy_to_msg(msg, skb->data, bytes);
>> +            if (err)
>> +                return err;
>> +
>> +            spin_lock_bh(&vvs->rx_lock);
>> +        }
>> +
>> +        total += skb->len;
>> +        hdr = virtio_vsock_hdr(skb);
>> +
>> +        if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOM) {
>> +            if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOR)
>> +                msg->msg_flags |= MSG_EOR;
>> +
>> +            break;
>> +        }
>> +    }
>> +
>> +    spin_unlock_bh(&vvs->rx_lock);
>> +
>> +    return total;
> 
> Should we return the minimum between total and len?

I guess no, because seqpacket dequeue callback always returns length of message,
then, in af_vsock.c we return either number of bytes read or length of message
depending on MSG_TRUNC flags.

Thanks, Arseniy

> 
> Thanks,
> Stefano
> 
>> +}
>> +
>> static int virtio_transport_seqpacket_do_dequeue(struct vsock_sock *vsk,
>>                          struct msghdr *msg,
>>                          int flags)
>> @@ -554,9 +611,9 @@ virtio_transport_seqpacket_dequeue(struct vsock_sock *vsk,
>>                    int flags)
>> {
>>     if (flags & MSG_PEEK)
>> -        return -EOPNOTSUPP;
>> -
>> -    return virtio_transport_seqpacket_do_dequeue(vsk, msg, flags);
>> +        return virtio_transport_seqpacket_do_peek(vsk, msg);
>> +    else
>> +        return virtio_transport_seqpacket_do_dequeue(vsk, msg, flags);
>> }
>> EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_dequeue);
>>
>> -- 
>> 2.25.1
>>
>
Stefano Garzarella June 27, 2023, 7:48 a.m. UTC | #3 
On Tue, Jun 27, 2023 at 07:34:29AM +0300, Arseniy Krasnov wrote:
>
>
>On 26.06.2023 19:28, Stefano Garzarella wrote:
>> On Sun, Jun 18, 2023 at 09:24:49AM +0300, Arseniy Krasnov wrote:
>>> This adds support of MSG_PEEK flag for SOCK_SEQPACKET type of socket.
>>> Difference with SOCK_STREAM is that this callback returns either length
>>> of the message or error.
>>>
>>> Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
>>> ---
>>> net/vmw_vsock/virtio_transport_common.c | 63 +++++++++++++++++++++++--
>>> 1 file changed, 60 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
>>> index 2ee40574c339..352d042b130b 100644
>>> --- a/net/vmw_vsock/virtio_transport_common.c
>>> +++ b/net/vmw_vsock/virtio_transport_common.c
>>> @@ -460,6 +460,63 @@ virtio_transport_stream_do_dequeue(struct vsock_sock *vsk,
>>>     return err;
>>> }
>>>
>>> +static ssize_t
>>> +virtio_transport_seqpacket_do_peek(struct vsock_sock *vsk,
>>> +                   struct msghdr *msg)
>>> +{
>>> +    struct virtio_vsock_sock *vvs = vsk->trans;
>>> +    struct sk_buff *skb;
>>> +    size_t total, len;
>>> +
>>> +    spin_lock_bh(&vvs->rx_lock);
>>> +
>>> +    if (!vvs->msg_count) {
>>> +        spin_unlock_bh(&vvs->rx_lock);
>>> +        return 0;
>>> +    }
>>> +
>>> +    total = 0;
>>> +    len = msg_data_left(msg);
>>> +
>>> +    skb_queue_walk(&vvs->rx_queue, skb) {
>>> +        struct virtio_vsock_hdr *hdr;
>>> +
>>> +        if (total < len) {
>>> +            size_t bytes;
>>> +            int err;
>>> +
>>> +            bytes = len - total;
>>> +            if (bytes > skb->len)
>>> +                bytes = skb->len;
>>> +
>>> +            spin_unlock_bh(&vvs->rx_lock);
>>> +
>>> +            /* sk_lock is held by caller so no one else can dequeue.
>>> +             * Unlock rx_lock since memcpy_to_msg() may sleep.
>>> +             */
>>> +            err = memcpy_to_msg(msg, skb->data, bytes);
>>> +            if (err)
>>> +                return err;
>>> +
>>> +            spin_lock_bh(&vvs->rx_lock);
>>> +        }
>>> +
>>> +        total += skb->len;
>>> +        hdr = virtio_vsock_hdr(skb);
>>> +
>>> +        if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOM) {
>>> +            if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOR)
>>> +                msg->msg_flags |= MSG_EOR;
>>> +
>>> +            break;
>>> +        }
>>> +    }
>>> +
>>> +    spin_unlock_bh(&vvs->rx_lock);
>>> +
>>> +    return total;
>>
>> Should we return the minimum between total and len?
>
>I guess no, because seqpacket dequeue callback always returns length of message,
>then, in af_vsock.c we return either number of bytes read or length of message
>depending on MSG_TRUNC flags.

Right! We should always return the total lenght of the packet.

Thanks,
Stefano

>
>Thanks, Arseniy
>
>>
>> Thanks,
>> Stefano
>>
>>> +}
>>> +
>>> static int virtio_transport_seqpacket_do_dequeue(struct vsock_sock *vsk,
>>>                          struct msghdr *msg,
>>>                          int flags)
>>> @@ -554,9 +611,9 @@ virtio_transport_seqpacket_dequeue(struct vsock_sock *vsk,
>>>                    int flags)
>>> {
>>>     if (flags & MSG_PEEK)
>>> -        return -EOPNOTSUPP;
>>> -
>>> -    return virtio_transport_seqpacket_do_dequeue(vsk, msg, flags);
>>> +        return virtio_transport_seqpacket_do_peek(vsk, msg);
>>> +    else
>>> +        return virtio_transport_seqpacket_do_dequeue(vsk, msg, flags);
>>> }
>>> EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_dequeue);
>>>
>>> -- 
>>> 2.25.1
>>>
>>
>
diff mbox series

Patch

diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index 2ee40574c339..352d042b130b 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -460,6 +460,63 @@  virtio_transport_stream_do_dequeue(struct vsock_sock *vsk,
 	return err;
 }
 
+static ssize_t
+virtio_transport_seqpacket_do_peek(struct vsock_sock *vsk,
+				   struct msghdr *msg)
+{
+	struct virtio_vsock_sock *vvs = vsk->trans;
+	struct sk_buff *skb;
+	size_t total, len;
+
+	spin_lock_bh(&vvs->rx_lock);
+
+	if (!vvs->msg_count) {
+		spin_unlock_bh(&vvs->rx_lock);
+		return 0;
+	}
+
+	total = 0;
+	len = msg_data_left(msg);
+
+	skb_queue_walk(&vvs->rx_queue, skb) {
+		struct virtio_vsock_hdr *hdr;
+
+		if (total < len) {
+			size_t bytes;
+			int err;
+
+			bytes = len - total;
+			if (bytes > skb->len)
+				bytes = skb->len;
+
+			spin_unlock_bh(&vvs->rx_lock);
+
+			/* sk_lock is held by caller so no one else can dequeue.
+			 * Unlock rx_lock since memcpy_to_msg() may sleep.
+			 */
+			err = memcpy_to_msg(msg, skb->data, bytes);
+			if (err)
+				return err;
+
+			spin_lock_bh(&vvs->rx_lock);
+		}
+
+		total += skb->len;
+		hdr = virtio_vsock_hdr(skb);
+
+		if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOM) {
+			if (le32_to_cpu(hdr->flags) & VIRTIO_VSOCK_SEQ_EOR)
+				msg->msg_flags |= MSG_EOR;
+
+			break;
+		}
+	}
+
+	spin_unlock_bh(&vvs->rx_lock);
+
+	return total;
+}
+
 static int virtio_transport_seqpacket_do_dequeue(struct vsock_sock *vsk,
 						 struct msghdr *msg,
 						 int flags)
@@ -554,9 +611,9 @@  virtio_transport_seqpacket_dequeue(struct vsock_sock *vsk,
 				   int flags)
 {
 	if (flags & MSG_PEEK)
-		return -EOPNOTSUPP;
-
-	return virtio_transport_seqpacket_do_dequeue(vsk, msg, flags);
+		return virtio_transport_seqpacket_do_peek(vsk, msg);
+	else
+		return virtio_transport_seqpacket_do_dequeue(vsk, msg, flags);
 }
 EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_dequeue);