[net-next,v4,02/12] vsock: read from socket's error queue
Commit Message
This adds handling of MSG_ERRQUEUE input flag in receive call. This flag
is used to read socket's error queue instead of data queue. Possible
scenario of error queue usage is receiving completions for transmission
with MSG_ZEROCOPY flag. This patch also adds new defines: 'SOL_VSOCK'
and 'VSOCK_RECVERR'.
Signed-off-by: Arseniy Krasnov <avkrasnov@salutedevices.com>
---
Changelog:
v1 -> v2:
* Place new defines for userspace to the existing file 'vm_sockets.h'
instead of creating new one.
v2 -> v3:
* Add comments to describe 'SOL_VSOCK' and 'VSOCK_RECVERR' in the file
'vm_sockets.h'.
* Reorder includes in 'af_vsock.c' in alphabetical order.
v3 -> v4:
* Update comments for 'SOL_VSOCK' and 'VSOCK_RECVERR' by adding more
details.
include/linux/socket.h | 1 +
include/uapi/linux/vm_sockets.h | 17 +++++++++++++++++
net/vmw_vsock/af_vsock.c | 6 ++++++
3 files changed, 24 insertions(+)
Comments
On Tue, Oct 10, 2023 at 10:15:14PM +0300, Arseniy Krasnov wrote:
>This adds handling of MSG_ERRQUEUE input flag in receive call. This flag
>is used to read socket's error queue instead of data queue. Possible
>scenario of error queue usage is receiving completions for transmission
>with MSG_ZEROCOPY flag. This patch also adds new defines: 'SOL_VSOCK'
>and 'VSOCK_RECVERR'.
>
>Signed-off-by: Arseniy Krasnov <avkrasnov@salutedevices.com>
>---
> Changelog:
> v1 -> v2:
> * Place new defines for userspace to the existing file 'vm_sockets.h'
> instead of creating new one.
> v2 -> v3:
> * Add comments to describe 'SOL_VSOCK' and 'VSOCK_RECVERR' in the file
> 'vm_sockets.h'.
> * Reorder includes in 'af_vsock.c' in alphabetical order.
> v3 -> v4:
> * Update comments for 'SOL_VSOCK' and 'VSOCK_RECVERR' by adding more
> details.
>
> include/linux/socket.h | 1 +
> include/uapi/linux/vm_sockets.h | 17 +++++++++++++++++
> net/vmw_vsock/af_vsock.c | 6 ++++++
> 3 files changed, 24 insertions(+)
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
@@ -383,6 +383,7 @@ struct ucred {
#define SOL_MPTCP 284
#define SOL_MCTP 285
#define SOL_SMC 286
+#define SOL_VSOCK 287
/* IPX options */
#define IPX_TYPE 1
@@ -191,4 +191,21 @@ struct sockaddr_vm {
#define IOCTL_VM_SOCKETS_GET_LOCAL_CID _IO(7, 0xb9)
+/* MSG_ZEROCOPY notifications are encoded in the standard error format,
+ * sock_extended_err. See Documentation/networking/msg_zerocopy.rst in
+ * kernel source tree for more details.
+ */
+
+/* 'cmsg_level' field value of 'struct cmsghdr' for notification parsing
+ * when MSG_ZEROCOPY flag is used on transmissions.
+ */
+
+#define SOL_VSOCK 287
+
+/* 'cmsg_type' field value of 'struct cmsghdr' for notification parsing
+ * when MSG_ZEROCOPY flag is used on transmissions.
+ */
+
+#define VSOCK_RECVERR 1
+
#endif /* _UAPI_VM_SOCKETS_H */
@@ -89,6 +89,7 @@
#include <linux/types.h>
#include <linux/bitops.h>
#include <linux/cred.h>
+#include <linux/errqueue.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/kernel.h>
@@ -110,6 +111,7 @@
#include <linux/workqueue.h>
#include <net/sock.h>
#include <net/af_vsock.h>
+#include <uapi/linux/vm_sockets.h>
static int __vsock_bind(struct sock *sk, struct sockaddr_vm *addr);
static void vsock_sk_destruct(struct sock *sk);
@@ -2137,6 +2139,10 @@ vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
int err;
sk = sock->sk;
+
+ if (unlikely(flags & MSG_ERRQUEUE))
+ return sock_recv_errqueue(sk, msg, len, SOL_VSOCK, VSOCK_RECVERR);
+
vsk = vsock_sk(sk);
err = 0;