Virtual (secure) IPv6: tunneling

modulename: ip6_vti.ko

configname: CONFIG_IPV6_VTI

Linux Kernel Configuration
└─>Networking support
└─>Networking options
└─>The IPv6 protocol
└─>Virtual (secure) IPv6: tunneling
In linux kernel since version 3.10 (release Date: 2013-06-30)  
Tunneling means encapsulating data of one protocol type within
another protocol and sending it over a channel that understands the
encapsulating protocol. This can be used with xfrm mode tunnel to give
the notion of a secure tunnel for IPSEC and then use routing protocol
on top.

source code: