Is udev necessary for NM plug-in?

[Mu Qiao <qiaomuf gmail com>]

Hi all,
I'm writing a plugin for Gentoo.

I've read the source code of ifupdown and ifcfg-rh. I find that
ifupdown use udev to bind device to connection. The main work it has
done during binding is getting the mac address of network interface
through udev API and adding it to corresponding connection setting.
However, I didn't find the same thing in ifcfg-rh.

So I've tried to omit the udev part for my gentoo plugin. After
starting NetworkManager, although I can see the connection managed by
my plugin via nm-applet, ifconfig command shows that the network isn't
correctly setup.
Do I need to set mac address for each connection to let them work
correctly? Or there are other things that I didn't handle in the right
way? I've tried to remove mac address saved in
/etc/sysconfig/network-scripts/ifcfg-eth*, but NM still works
correctly.
-- 
Best wishes,
Mu Qiao