Mobile network configuration

[David Z Maze <dmaze@debian.org>]

I have a fairly new laptop running Debian unstable.  It has on-board
MiniPCI 802.11 wireless (yay!).  I'm using kernel 2.4.12, with the
driver modules from the pcmcia-source package (specifically, the
wvlan_cs module).

What I'd like to do is have the laptop automatically detect the local
network and configure itself appropriately at boot time.  In
particular:

-- If I'm at home, use a known static IP address.
-- If I'm at work, use one set of access points preferentially over
   another, and get an address via DHCP.
-- Otherwise, use any access point that's available and get an address
   via DHCP.

I'm assuming there's some way I can test based on access-point name to
determine "at work" vs. "at home" vs. "none of the above".  (iwconfig
does give different ESSID names.)

So, questions:

(1) How do I set this up?  It looks like there's no easy way to do
    this using the pcmcia infrastructure.  The ifupdown stuff in
    unstable looks like it can pick a network configuration based on
    some script, but the only documentation is examples in
    /usr/share/doc/ifupdown/examples, which are somewhat useful but
    not completely informative.  Is the best way to do it really to
    say "force the first ESSID, and if there's signal, use it, else
    repeat?"

(2) Where do I start services (zhm, ntp, possibly others) that should
    only be started when the network is up?  pcmcia stuff suggests
    adding it to start_fn in /etc/pcmcia/network.opts, but this won't
    scale well, particularly if I need to add the same things to
    start_fn in three different places.  I thought I saw a hint
    somewhere that symlinking init scripts into /etc/network/if-up.d
    would DWIW.

(3) Is all of this documented somewhere, and I just missed it?  (The
    Wireless-HOWTO is really hard to read and talks a lot about
    network setups from the AP end, which I really don't care about.)

Right now I'm doing this using 'cardctl scheme ...', which works but
isn't as automated as I'd like.  It'd be nice if the PCMCIA scripts
gave me more support, but the things you can configure on (scheme,
slot, driver, MAC address) are mostly fixed, so this really isn't a
useful set of configuration options.

Thanks,

-- 
David Maze         dmaze@debian.org      http://people.debian.org/~dmaze/
"Theoretical politics is interesting.  Politicking should be illegal."
	-- Abra Mitchell