Network address class

[David M . Arroyo Díaz]

I've looked at the defined classes output that cfengine shows when it's run
in debug & parse-only mode, and I didn't found any class that points to the
network address of the server.
For example, I've got a host with the IP address 192.168.1.23, and it's
network address is 192.168.1.0 (because it belongs to a simple class c
subnet).

The question is simple: how can I define an aditional class that references
this parameter? Should I try a custom shell script for this purpose?

Thanks in advance.