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Date: Tue, 28 Aug 2007 21:37:18 +0100
From: "Bruce M. Simpson" <bms@FreeBSD.org>
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To: "Christian S.J. Peron" <csjp@FreeBSD.org>
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Cc: FreeBSD Current <current@freebsd.org>,
	Andrew Thompson <thompsa@FreeBSD.org>
Subject: Re: multicast packets from bpf
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Christian S.J. Peron wrote:
> I think that tap(4) is a bit different since the only kind of frames it
> handles are Ethernet.

As Andrew points out the tapwrite check probably isn't needed now.

>   This is not the case for bpf(4).  I wonder if it
> makes sense to add this check into ether_output()? IIRC bpf will call
> the network interface's output routine, in the Ethernet/bridge case it
> should be ether_output().
>   

This approach avoids touching the device-independent paths, and, 
providing the check resides in the AF_UNSPEC case (as ARP resolution 
should do the right thing) is reasonably neat.

But it doesn't handle the case where there are link-layer netgraph nodes 
between bpf and if_bridge, something which the first change would deal with.

regards
BMS