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

[Luigi Leonardi]

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.deme...@gmail.com>
Signed-off-by: Luigi Leonardi <luigi.leona...@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