Subject: hme SIMPLEX and bpf: duplicate copies
To: None <>
From: Greg Troxel <>
List: tech-net
Date: 02/02/2004 11:29:20
[on tech-net since really this is about the right way to do bpf on
interfaces that aren't SIMPLEX.]

I have an ultra2 with builtin hme and a qfe.
I am running 1.6.2ish with the set-SIMPLEX-based-on-FDX patch from
When running tcpdump, I notice 2 copies of outgoing packets.

In src/sys/dev/ic/hme.c I see that the bpf_mtap call for the outgoing
packet is not conditionalized on SIMPLEX, and the incoming call does
not check the mac src.

My inclination is to decline to tap the outgoing packets if SIMPLEX is
not set.