netifd is an RPC-capable daemon written in C for better access to kernel APIs with the ability to listen on netlink events. Netifd has replaced the old OpenWrt-network configuration scripts, the actual scripts that configured the network e.g.,
The WPAN support is now a simple clone of 802.11 support which include C code for netifd and Ash scripts to handle wpan interface.
The hardware platform I use is ci40 from Imagination, which has ca2810 802.15.4 radio chip. For most router without 802.15.4 hardware chips, fakelb is a good choice for testing. here is a simple tutorial how to setup a 6lowpan test network.
The OpenWRT source code is here