Subject: Re: access point list from Lucent wireless cards
To: None <>
From: Atsushi Onoe <>
List: current-users
Date: 09/19/2001 13:58:24
> I'd like to have a device (/dev/wi0 or something) that can be used as
> a method to pass data into and out of the kernel.  I'd use this as a
> way to pass along packets that perhaps I don't want to send to the
> IP stack (management, encrypted or undecryptable frames, etc) as
> well as a general purpose async notification pipe for monitoring
> AP associations, signal strengths, etc.

I've heard BSD/OS uses BPF to capture 802.11 packets, which is basically
the right way, IMHO.

But it is hard to send 802.11 frame via BPF because it is not clear
what field should be filled by the driver.  Obviously, some information
such as seqence control should be consistent with the normal IP packets.
And there may be a discussion who should take care of encryption.
Some device cannot skip hardware encryption/decryption engine.

And if we change the bpf type from DLT_EN10MB, the application like
dhclient(8) must be updated.  So I'm thinking the way to creating switch
controlled by ioctl for bpf device.

Anyway, creating device and introducing device specific utility for each
wireless device is not a good idea, IMO.  Please make it generic among
number of wireless devices.

Atsushi Onoe