Date: Wed, 19 Oct 2005 10:26:10 -0400 From: "Andrew Atrens" <atrens@nortel.com> To: Andrew Thompson <thompsa@freebsd.org> Cc: freebsd-current@freebsd.org, Jiri Mikulas <konfer@mikulas.com> Subject: Re: ath client bridge Message-ID: <43565782.8080706@nortel.com> In-Reply-To: <20051019091559.GA45009@heff.fud.org.nz> References: <43560B6A.4070505@mikulas.com> <20051019091559.GA45009@heff.fud.org.nz>
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Andrew Thompson wrote: > On Wed, Oct 19, 2005 at 11:01:30AM +0200, Jiri Mikulas wrote: > >>Hello >>I have problem to setup bridging box with ath in client mode and if_bridge >>When card is in AP mode, everything is ok, but if I want to run card in >>client mode, bridging is not working. >>Here are my testing steps: (it's quite long, so I prefer put URL there :) ) > > > Bridging on the client side of a wireless connection is not supported > and has to do with the 801.11 frame format. The problem is that the > client only registers its own MAC address with the AP, so the bridged > clients do not get a reply (as far as I understand). Yah, the 802.11 header only has room for three addresses. The AP uses them as - ssid src dest (in this case src is the *real* src of the packet hence the AP itself can bridge) The client uses - ssid src dest (in this case src *must* be the client mac, hence the client can't bridge packets from other macs) There is a four address version of the packet header, but as I recall the fourth address is used by TKIP. So it's a problem with 802.11 standard. I think that's why they came up with WDS. I think there's some support for WDS in MadWiFi, but not yet in the BSD stack(s). Another thing that you *could* do - that I'm actually working on for DragonFly, is to add support for bridging GIF interfaces. Or, if it was possible add support for directly bridging across IPsec - I think even transport mode support would suffice, as long as in either case the AP and client were endpoints for the IPsec connection. Andrewhome | help
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