Support for IP version 6 (IPv6).

For general information about IPv6, see
<https://en.wikipedia.org/wiki/IPv6>.
For specific information about IPv6 under Linux, see
Documentation/networking/ipv6.txt and read the HOWTO at
<http://www.tldp.org/HOWTO/Linux+IPv6-HOWTO/>

To compile this protocol support as a module, choose M here: the
module will be called ipv6.