[PATCH net-next 1/3] vsock: add support for SIOCOUTQ ioctl for all vsock socket types.

[Luigi Leonardi <luigi.leonardi@outlook.com>]

This add support for ioctl(s) for SOCK_STREAM SOCK_SEQPACKET and SOCK_DGRAM
in AF_VSOCK.
The only ioctl available is SIOCOUTQ/TIOCOUTQ, which returns the number
of unsent bytes in the socket. This information is transport-specific
and is delegated to them using a callback.

Suggested-by: Daan De Meyer <daan.j.demeyer@gmail.com>
Signed-off-by: Luigi Leonardi <luigi.leonardi@outlook.com>
---
 include/net/af_vsock.h   |  1 +
 net/vmw_vsock/af_vsock.c | 42 +++++++++++++++++++++++++++++++++++++---
 2 files changed, 40 insertions(+), 3 deletions(-)

diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
index 535701efc1e5..cd4311abd3c9 100644
--- a/include/net/af_vsock.h
+++ b/include/net/af_vsock.h
@@ -137,6 +137,7 @@ struct vsock_transport {
 	u64 (*stream_rcvhiwat)(struct vsock_sock *);
 	bool (*stream_is_active)(struct vsock_sock *);
 	bool (*stream_allow)(u32 cid, u32 port);
+	int (*stream_bytes_unsent)(struct vsock_sock *vsk);
 
 	/* SEQ_PACKET. */
 	ssize_t (*seqpacket_dequeue)(struct vsock_sock *vsk, struct msghdr *msg,
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 54ba7316f808..991e9edfa743 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -112,6 +112,7 @@
 #include <net/sock.h>
 #include <net/af_vsock.h>
 #include <uapi/linux/vm_sockets.h>
+#include <uapi/asm-generic/ioctls.h>
 
 static int __vsock_bind(struct sock *sk, struct sockaddr_vm *addr);
 static void vsock_sk_destruct(struct sock *sk);
@@ -1292,6 +1293,41 @@ int vsock_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
 }
 EXPORT_SYMBOL_GPL(vsock_dgram_recvmsg);
 
+static int vsock_do_ioctl(struct socket *sock, unsigned int cmd,
+			  int __user *arg)
+{
+	struct sock *sk = sock->sk;
+	int retval = -EOPNOTSUPP;
+	struct vsock_sock *vsk;
+
+	vsk = vsock_sk(sk);
+
+	switch (cmd) {
+	case SIOCOUTQ:
+		if (vsk->transport->stream_bytes_unsent) {
+			if (sk->sk_state == TCP_LISTEN)
+				return -EINVAL;
+			retval = vsk->transport->stream_bytes_unsent(vsk);
+		}
+		break;
+	default:
+		retval = -EOPNOTSUPP;
+	}
+
+	if (retval >= 0) {
+		put_user(retval, arg);
+		retval = 0;
+	}
+
+	return retval;
+}
+
+static int vsock_ioctl(struct socket *sock, unsigned int cmd,
+		       unsigned long arg)
+{
+	return vsock_do_ioctl(sock, cmd, (int __user *)arg);
+}
+
 static const struct proto_ops vsock_dgram_ops = {
 	.family = PF_VSOCK,
 	.owner = THIS_MODULE,
@@ -1302,7 +1338,7 @@ static const struct proto_ops vsock_dgram_ops = {
 	.accept = sock_no_accept,
 	.getname = vsock_getname,
 	.poll = vsock_poll,
-	.ioctl = sock_no_ioctl,
+	.ioctl = vsock_ioctl,
 	.listen = sock_no_listen,
 	.shutdown = vsock_shutdown,
 	.sendmsg = vsock_dgram_sendmsg,
@@ -2286,7 +2322,7 @@ static const struct proto_ops vsock_stream_ops = {
 	.accept = vsock_accept,
 	.getname = vsock_getname,
 	.poll = vsock_poll,
-	.ioctl = sock_no_ioctl,
+	.ioctl = vsock_ioctl,
 	.listen = vsock_listen,
 	.shutdown = vsock_shutdown,
 	.setsockopt = vsock_connectible_setsockopt,
@@ -2308,7 +2344,7 @@ static const struct proto_ops vsock_seqpacket_ops = {
 	.accept = vsock_accept,
 	.getname = vsock_getname,
 	.poll = vsock_poll,
-	.ioctl = sock_no_ioctl,
+	.ioctl = vsock_ioctl,
 	.listen = vsock_listen,
 	.shutdown = vsock_shutdown,
 	.setsockopt = vsock_connectible_setsockopt,
-- 
2.34.1