vsock: read from socket's error queue

[ Upstream commit 49dbe25adac42d3e06f65d1420946bec65896222 ]

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>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/include/linux/socket.h b/include/linux/socket.h
index 39b74d8..cfcb7e2 100644 (file)
--- a/include/linux/socket.h
+++ b/include/linux/socket.h
@@ -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

diff --git a/include/uapi/linux/vm_sockets.h b/include/uapi/linux/vm_sockets.h
index c60ca33..ed07181 100644 (file)
--- a/include/uapi/linux/vm_sockets.h
+++ b/include/uapi/linux/vm_sockets.h
@@ -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 */

diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 020cf17..ccd8cef 100644 (file)
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -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);
@@ -2134,6 +2136,10 @@ 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;