Re: [PATCH net-next 2/2] tun: enable socket system calls

From: Alex Gartrell
Date: Fri Dec 26 2014 - 14:16:51 EST

Hello Jason,

Thanks for commenting.

On 12/26/14 4:43 AM, Jason Wang wrote:

On 12/26/2014 02:50 PM, Alex Gartrell wrote:
By setting private_data to a socket and private_data_is_socket to true, we
can use the socket syscalls. We also can't just blindly use private_data
anymore, so there's a __tun_file_get function that returns the container_of
private_data appropriately.

So this in fact expose other socket syscalls to userspace. But some of
proto_ops was not supported. E.g consider what happens if a bind() was
called for tun socket?

Yeah, I erroneously assumed that NULL => sock_no_*, but a quick glance assures me that that's not the case. In this case, I'd need to introduce another patch that sets all of the additional ops to sock_no_*.

+static struct tun_file *tun_file_from_file(struct file *file)
+ struct socket *s = (struct socket *)file->private_data;
+ if (!s)

Can s be NULL here? If yes, why tun_get() didn't check for NULL?

This check is just to ensure that tun_get_socket continues to work in the right way when passed a file with private_data set to NULL.

Alex Gartrell <agartrell@xxxxxx>
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at