tree 9a1c59c0c7fa60a3bc2c86c8e918addd14ab6d15
parent b94d525e58dc9638dd3f98094cb468bcfb262039
author Steffen Klassert <steffen.klassert@secunet.com> 1411369868 +0200
committer David S. Miller <davem@davemloft.net> 1411706490 -0400

ip_tunnel: Don't allow to add the same tunnel multiple times.

When we try to add an already existing tunnel, we don't return
an error. Instead we continue and call ip_tunnel_update().
This means that we can change existing tunnels by adding
the same tunnel multiple times. It is even possible to change
the tunnel endpoints of the fallback device.

We fix this by returning an error if we try to add an existing
tunnel.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>