libnetfilter_log is a userspace library providing interface to packets
that have been logged by the kernel packet filter. It is is part of
a system that deprecates the old syslog/dmesg based packet logging. 
This library has been previously known as libnfnetlink_log. 

libnetfilter_log is used by ulogd2.

This requires libnfnetlink, which is also available at SlackBuilds.org
and a kernel that includes the nfnetlink_log subsyste (i.e. 2.6.14 or later).