Knockd in Chaos Calmer

Knocked is removed from Chaos Calmer, actually, it is not removed. As openwrt package is maintained by community, this obsolete program will be forgotten if no one takes care of it. However, this little program means some values for my little server...

What's is port knocking? http://blogger.gtwang.org/2013/10/port-knocking.html

Hope that I can't build it in my openwrt condition.,