Re: [RFC PATCH v4 07/17] af_vsock: rest of SEQPACKET support

[Stefano Garzarella <sgarzare@redhat.com>]

On Sun, Feb 07, 2021 at 06:16:12PM +0300, Arseny Krasnov wrote:
>This does rest of SOCK_SEQPACKET support:
>1) Adds socket ops for SEQPACKET type.
>2) Allows to create socket with SEQPACKET type.
>
>Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
>---
> net/vmw_vsock/af_vsock.c | 37 ++++++++++++++++++++++++++++++++++++-
> 1 file changed, 36 insertions(+), 1 deletion(-)
>
>diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
>index a033d3340ac4..c77998a14018 100644
>--- a/net/vmw_vsock/af_vsock.c
>+++ b/net/vmw_vsock/af_vsock.c
>@@ -452,6 +452,7 @@ int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk)
> 		new_transport = transport_dgram;
> 		break;
> 	case SOCK_STREAM:
>+	case SOCK_SEQPACKET:
> 		if (vsock_use_local_transport(remote_cid))
> 			new_transport = transport_local;
> 		else if (remote_cid <= VMADDR_CID_HOST || !transport_h2g ||
>@@ -459,6 +460,15 @@ int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk)
> 			new_transport = transport_g2h;
> 		else
> 			new_transport = transport_h2g;
>+
>+		if (sk->sk_type == SOCK_SEQPACKET) {
>+			if (!new_transport ||
>+			    !new_transport->seqpacket_seq_send_len ||
>+			    !new_transport->seqpacket_seq_send_eor ||
>+			    !new_transport->seqpacket_seq_get_len ||
>+			    !new_transport->seqpacket_dequeue)
>+				return -ESOCKTNOSUPPORT;
>+		}

Maybe we should move this check after the try_module_get() call, since 
the memory pointed by 'new_transport' pointer can be deallocated in the 
meantime.

Also, if the socket had a transport before, we should deassign it before 
returning an error.

> 		break;
> 	default:
> 		return -ESOCKTNOSUPPORT;
>@@ -684,6 +694,7 @@ static int __vsock_bind(struct sock *sk, struct sockaddr_vm *addr)
>
> 	switch (sk->sk_socket->type) {
> 	case SOCK_STREAM:
>+	case SOCK_SEQPACKET:
> 		spin_lock_bh(&vsock_table_lock);
> 		retval = __vsock_bind_connectible(vsk, addr);
> 		spin_unlock_bh(&vsock_table_lock);
>@@ -769,7 +780,7 @@ static struct sock *__vsock_create(struct net *net,
>
> static bool sock_type_connectible(u16 type)
> {
>-	return type == SOCK_STREAM;
>+	return (type == SOCK_STREAM) || (type == SOCK_SEQPACKET);
> }
>
> static void __vsock_release(struct sock *sk, int level)
>@@ -2199,6 +2210,27 @@ static const struct proto_ops vsock_stream_ops = {
> 	.sendpage = sock_no_sendpage,
> };
>
>+static const struct proto_ops vsock_seqpacket_ops = {
>+	.family = PF_VSOCK,
>+	.owner = THIS_MODULE,
>+	.release = vsock_release,
>+	.bind = vsock_bind,
>+	.connect = vsock_connect,
>+	.socketpair = sock_no_socketpair,
>+	.accept = vsock_accept,
>+	.getname = vsock_getname,
>+	.poll = vsock_poll,
>+	.ioctl = sock_no_ioctl,
>+	.listen = vsock_listen,
>+	.shutdown = vsock_shutdown,
>+	.setsockopt = vsock_connectible_setsockopt,
>+	.getsockopt = vsock_connectible_getsockopt,
>+	.sendmsg = vsock_connectible_sendmsg,
>+	.recvmsg = vsock_connectible_recvmsg,
>+	.mmap = sock_no_mmap,
>+	.sendpage = sock_no_sendpage,
>+};
>+
> static int vsock_create(struct net *net, struct socket *sock,
> 			int protocol, int kern)
> {
>@@ -2219,6 +2251,9 @@ static int vsock_create(struct net *net, struct socket *sock,
> 	case SOCK_STREAM:
> 		sock->ops = &vsock_stream_ops;
> 		break;
>+	case SOCK_SEQPACKET:
>+		sock->ops = &vsock_seqpacket_ops;
>+		break;
> 	default:
> 		return -ESOCKTNOSUPPORT;
> 	}
>-- 
>2.25.1
>