tun: Get skfilter layout

The only thing we may have from tun device is the fprog, whic contains
the number of filter elements and a pointer to (user-space) memory
where the elements are. The program itself may not be available if the
device is persistent and detached.

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 10 insertions, 0 deletions

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 6acbdbccebcd..60a1e93e9d35 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -2042,6 +2042,16 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
                 tun_detach_filter(tun, tun->numqueues);
                 break;
 
+        case TUNGETFILTER:
+                ret = -EINVAL;
+                if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
+                        break;
+                ret = -EFAULT;
+                if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
+                        break;
+                ret = 0;
+                break;
+
         default:
                 ret = -EINVAL;
                 break;