IPv6: IP-in-IPv6 tunnel (RFC2473)

modulename: ip6_tunnel.ko

configname: CONFIG_IPV6_TUNNEL

Linux Kernel Configuration
└─>Networking
└─>Networking options
└─>IPv6: IP-in-IPv6 tunnel (RFC2473)
In linux kernel since version 2.6.12  
Support for IPv6-in-IPv6 and IPv4-in-IPv6 tunnels described in
RFC 2473.

If unsure, say N.

source code:
net/ipv6/ip6_tunnel.c