Subject: Re: nul interface?
To: Andrew Brown <>
From: Alfred Perlstein <>
List: tech-net
Date: 10/25/2001 13:02:41
* Andrew Brown <> [011025 11:53] wrote:
> so i slapped in a cloning nul interface implementation and i'm struck
> by one thing.  i can ping the ipv6 link-local address, but i can't see
> the packets (on nul0).  i take it this is because the local address
> gets a route automatically inserted for it via lo0.  is there any way
> around this?  should i mark the interface as IFF_LOOPBACK?

Since I can't see the code except the little snippet you posted
which seems to neglect pushing packets into bpf, maybe that's
what you're missing?

see (in 1.5.x) /usr/src/sys/dev/pcmcia/if_wi.c:wi_start()
or (in -current) /usr/src/sys/dev/ic/wi.c:wi_start()

         * If there's a BPF listner, bounce a copy of
         * this frame to him.
        if (ifp->if_bpf)
                bpf_mtap(ifp->if_bpf, m0);


hope this helps.

-Alfred Perlstein []
'Instead of asking why a piece of software is using "1970s technology,"
 start asking why software is ignoring 30 years of accumulated wisdom.'