The libmaxminddb library provides a C library for reading MaxMind DB
files, including the GeoIP2 databases from MaxMind. This is a custom
binary format designed to facilitate fast lookups of IP addresses
while allowing for great flexibility in the type of data associated
with an address.

The MaxMind DB format is an open format.
The spec is available at http://maxmind.github.io/MaxMind-DB/.
This spec is licensed under the Creative Commons Attribution-ShareAlike
3.0 Unported License.