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

[Stefano Garzarella <sgarzare@xxxxxxxxxx>]

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@xxxxxxxxxxxxx>
> ---
> 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