wireless-to-wired bridging

[Lowell Gilbert]

"Reid Linnemann" <lreid at cs.okstate.edu> writes:

> I have a question that is more of a networking question than a BSD
> question, but I am hoping someone out there has faced this same dilemma
> before and has some advice:
> 
> I have a FreeBSD machine running -current that servers as a router for my
> home LAN, using nat. I recently tossed in a DLink DWL-G520 wireless card
> (ath0), and bridged that interface to the internal LAN interface on the
> machine (rl1). After a bit of configurating, I had the ath interface in
> hostap mode, and everything was working great - except the wired clients
> cannot route to eachother.
> 
> I am suspicious that, since the wired network is in AP mode, if a
> wireless client wants to send a packet to another wireless client, it
> must be sent to the AP, which should theoretically redirect the packet
> to the appropriate host on the wireless net. In the wired network, a
> switch handles this automagically on the datalink layer without those
> messages hitting the rl1 interface of the BSD router. I've looked at
> the bridge code, and it seems that unless a packet is multicast or
> broadcast it will be copied to the other bridge interfaces but not
> returned to the original caller. Since the packets being sent between
> wireless clients are not broadcast, I think they are getting dumped into
> the black hole of the wired LAN, and not being processed and pumped back
> out through the ath interface. Is this a correct assumption? Are there
> ways I can overcome this problem?

I think that you mixed up the terms "wired" and "wireless" in some
(but not all) of the uses above.  This makes it somewhat harder to
follow the problem.

I would actually suggest that you make the wireless link a separate
subnet from the Ethernets.  802.11 really is a different protocol than
802.1, and I don't think you'll get any performance benefit from
bridging in this case.