IP VTI (Virtual Tunnel Interface) is used to create a virtual device
for IPsec VPN (similar to OpenVPN).
Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@44606 3c298f89-4303-0410-b956-a3cf2f4a3e73