[patch] wireless network support

[David Zeuthen]

On Tue, May 25, 2004 at 09:48:04PM -0400, Joe Shaw wrote:
> Hi,
> 
> The attached patch adds support for the linux wireless extensions.  It
> uses the sysfs and iwlib interfaces for getting the current wireless
> settings as well as scanning for available networks.
> 

Yay, I think this is quite nice. One could wonder whether this is
stretching what the HAL should do; my take on that is that it makes
good sense to do this; I mean, it's the same thing we do for wired
networks with the property net.ethernet.link. I'm curious what other
people think?

My only concern is that might cause a storm of D-BUS signal emissions
and callouts; Kay talked about adding attributes to properties so
perhaps one day we could say something like

 hal_property_set_attribute (d, "net.wireless.network0.noise", 
                             HAL_PROP_ATTR_NO_CALLOUT|
                             HAL_PROP_ATTR_NO_MASS_EMISSION);

meaning that D-BUS clients only get updates if they actively watch
the device, and there will be no callouts in property.d from changes
to this property. 

Of course, this would require API-changes in libhal and in the D-BUS
network API offered. And we'd have to check that D-BUS can do this,
cf. the signal emission rules in the system message bus.

> The main strike against this patch is that it adds iwlib as a
> dependency.  We could either continue with that or import part (or all)
> of the code into hal.  Unfortunately the interfaces between the kernel
> and user space are so tightly intertwined that I don't think we could
> have a smaller, separate implementation.
> 

I think it would be rather unconstructive to duplicate code for the
sake of removing dependencies (and iwlib isn't really a policital
target like some other deps), so can't we just make this a
compile-time option? If distribution vendors are supporting wireless
ethernet they sure have iwlib available anyway.

My only other comment is that the properties should be called
net.ethernet.wireless instead of just net.wireless, since other
wireless networking technologies may or may not exist.

>   net.wireless = true  (bool)

Can we call this net.ethernet.is_wireless instead to follow what we do
(or should do, I'll check when updating the spec which is RSN :-]) in
other parts of the HAL?

> Enjoy.
> 

Cheers,
David

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