libnetfilter_queue is a userspace library providing an API to packets that have been queued by the kernel packet filter. It is is part of a system that deprecates the old ip_queue / libipq mechanism.
Created attachment 92913 [details] libnetfilter_queue-0.0.12.ebuild
This is now in the sunrise overlay. You can find it at: http://gentoo-sunrise.org/svn/reviewed/net-firewall/libnetfilter_queue
In portage tree in net-libs/libnetfilter_queue