cvs commit: src/sys/dev/bge if_bge.c

Peter Jeremy peterjeremy at
Wed Sep 20 02:28:49 PDT 2006

On Wed, 2006-Sep-20 09:52:36 +0100, David Malone wrote:
>Putting ethernet specific code in bpf_* feels like a bad idea.

Is this any worse than having ethernet specific code in the mbuf header?

> It
>should be possible to leave hardware assisted VLAN tagging on and
>get ether input to reinsert the tag only in cases where there is a
>bpf listener.

This could still be seen as a layering violation but is probably cleaner.

>(It's interesting to note that as ethernet cards introduce more
>features it is getting harder for us to tell what we put on the

This probably makes it more critical for bpf to not automatically
disable NIC features, otherwise we run the risk of introducing
heisenbugs in the network system.

>With VLAN tagging we can't trust the VLAN tag.

Unlike checksums etc, the kernel must be able to determine the VLAN
tag to be able to process the packet.  The problem is that it isn't
where bpf expects.

Peter Jeremy
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