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 de3701a2a2129dd6357f1910ec4878cb1005eaf9..1db29aab8f9c3caf66de143505a4aad6c54719ba 100644 (file)
--- a/include/linux/socket.h
+++ b/include/linux/socket.h
@@ -376,6 +376,7 @@ 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 c60ca33eac594bbed44b87ab416087090a352da9..ed07181d4eff917591dd459f4325078b33957bbe 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 8360c790a8a0116cb8fce7f1429805e74950c034..84471745c0829dafe15a6f6baf51b42757d5a1fd 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);
@@ -2096,6 +2098,10 @@ 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;