+ case TUNGETVNETHDRSZ:
+ vnet_hdr_sz = tun->vnet_hdr_sz;
+ if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
+ ret = -EFAULT;
+ break;
+
+ case TUNSETVNETHDRSZ:
+ if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
+ ret = -EFAULT;
+ break;
+ }
+ if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
+ ret = -EINVAL;
+ break;
+ }
+
+ tun->vnet_hdr_sz = vnet_hdr_sz;
+ break;
+