Adding an additional network from plugin with triggering the relevant smart proxies

has anybody an idea on how to extend an existing plugin to add a new
network interface to a node and additionally trigger the smartproxy for the
subnet of the interface.

This means I'll either call the smart-proxy directly for the given network
or add the a full network interface (interface section) and trigger the
smartproxies for that subnet.

Can anybody help or just point me to where to find that in foreman source