eeebuntu tip: ifup/down for NetworkManager

By switching to NetworkManager, I lost the use of the Linux ifup/ifdown scripts for quickly bringing network interfaces up and down. (These scripts rely on the information in /etc/network/interfaces, which I've stripped bare to transfer control to NetworkManager.)

Now, with nm-applet and kin, I have no real need or desire to control my network interfaces from the shell. However, some of my other scripts do -- in particular, when suspending and resuming the machine, I need to remove/reload the Atheros kernel modules, and I can't do that while the interface is up.

Also, my keyboard has a cute little "Wifi On/Off" button that I want to work. (More info on that in a later post.)

Fortunately, the solution turns out to be dead-simple: NetworkManager's dbus API exposes methods for bringing the network up and down.

To bring all NetworkManager-controlled interfaces down:

dbus-send --system --type=method_call \
  --dest=org.freedesktop.NetworkManager \
  /org/freedesktop/NetworkManager \
  org.freedesktop.NetworkManager.sleep

(Yes, all those switches are necessary.)

To bring 'em back up:

dbus-send --system --type=method_call \
  --dest=org.freedesktop.NetworkManager \
  /org/freedesktop/NetworkManager \
  org.freedesktop.NetworkManager.wake

In my case, I dropped these into scripts in /etc/acpi/suspend.d and /etc/acpi/resume.d, respectively, alongside their old-school ifup/down counterparts. Works great, assuming the drivers come back up; I'll post the trick for that in a subsequent post. (I'm transcribing my porting notes as fast as I can here.)