Subject: Re: prism DLT type and wi(4)
To: None <>
From: David Young <>
List: tech-net
Date: 10/21/2002 12:31:33
I do not know if it is compatible with other BSDs. I did not think other

I have discovered that in libpcap and in ethereal, DLT_PRISM_HEADER is
the 144-byte header returned by the Prism monitor mode. We do not have
a monitor mode, yet, so I am going to skip DLT_PRISM_HEADER.

I propose to call the header I described in my last e-mail,

DLT_SHORT_PRISM_HEADER is useful for watching signal/noise, data rate,
etc., during normal STA operations. (Monitor mode suspends normal STA
operations, so it is not always the right choice.)

I will send a patch, soon.

I wonder what you think about the generic radio DLT I propose?


On Mon, Oct 21, 2002 at 06:51:16PM +0900, Atsushi Onoe wrote:
> > Will anyone object if I modify wi(4) so that it does not pass to bpf
> > the entire Prism frame, which consists of
> > but I omit the data length and the ethernet header, instead?
> I'm sorry I didn't check compatibility by myself, but is it compatible
> with other BSDs?  I think that DLT_PRISM_HEADER should be compatible among
> BSDs at least, and I'm not sure your proposal is either fixing current
> incompatibilty or changing current definition.
> Atsushi Onoe

David Young             OJC Technologies      Engineering from the Right Brain
                        Urbana, IL * (217) 278-3933