tun: TUNGETIFF interface to query name and flags
Add a TUNGETIFF interface so that userspace can query a
tun/tap descriptor for its name and flags.
This is needed because it is common for one app to create
a tap interface, exec another app and pass it the file
descriptor for the interface. Without TUNGETIFF the spawned
app has no way of detecting wheter the interface has e.g.
IFF_VNET_HDR set.
Signed-off-by: Mark McLoughlin <markmc@redhat.com>
Acked-by: Max Krasnyansky <maxk@qualcomm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/if_tun.h b/include/linux/if_tun.h
index 4c6307a..8529f57 100644
--- a/include/linux/if_tun.h
+++ b/include/linux/if_tun.h
@@ -45,6 +45,7 @@
#define TUNGETFEATURES _IOR('T', 207, unsigned int)
#define TUNSETOFFLOAD _IOW('T', 208, unsigned int)
#define TUNSETTXFILTER _IOW('T', 209, unsigned int)
+#define TUNGETIFF _IOR('T', 210, unsigned int)
/* TUNSETIFF ifr flags */
#define IFF_TUN 0x0001