SlackBuildsOrg/network/ipv6calc

ipv6calc is a small utility written in programming language C to manipulate
(not only) IPv6 addresses. Intentions were convering a given IPv6 address into
compressed format, convering a given IPv6 address into the same format like
shown in /proc/net/if_inet6 and (because it was not difficulty) migrating the
Perl program ip6_int into. Now only one utiltity is needed to do a lot.
 
This utility was also used in the past to extend features on
network-functions-ipv6 library, used by initscripts-ipv6.

To enable IP2Location support you will need to install the optional dependency
ip2location-c first, and then pass:

  IP2LOCATION=yes

to this Slackbuild.