Subject: Re: adding an 802.11 data link type
To: Atsushi Onoe <>
From: Bill Studenmund <>
List: tech-net
Date: 08/08/2002 10:08:24
On Thu, 8 Aug 2002, Atsushi Onoe wrote:

> > So if I understand your code right, (ic->ic_rawbpf) is a necessary but not
> > sufficient condition to hand the packet off to bpf_mtap. The bpf system
> > would have had to ask for that packet type too. So something like:
> > if ((ic->ic_rawbpf) && (ic->ic_raw_bpfcount))
> > 	bpf_mtap(ic->ic_rawbpf, m0);
> Please note that this interface is very similar to existing bpf hook.
> So the value of ic->ic_rawbpf remains NULL unless someone issues BPFSETIF
> and BIOCSDLT, and recovered to NULL when the bpf listener closes bpf.
> The number of opening listeners are counted in bpf itself.

How does bpf communicate what kind of packets it wants to the driver?

Take care,