On Wed, Aug 3, 2011 at 5:44 PM, Ben Greear <greearb@xxxxxxxxxxxxxxx> wrote: > On 08/03/2011 03:37 PM, Sam Leffler wrote: >> >> On Tue, Aug 2, 2011 at 10:33 PM, Ben Greear<greearb@xxxxxxxxxxxxxxx> >> wrote: >>> >>> We have some interest in being able to bridge wired systems to >>> (virtual) STA interfaces, primarily for using third-party >>> traffic generation tools over virtual stations. >>> >>> I was thinking of writing a sta-bridge module that mapped >>> incoming packets on a wired interface to a STA with MAC >>> that matched the source MAC of the packet. All packets >>> received on the STA would be forwarded un-modified out >>> the wired port. >>> >>> I think this would allow someone to create a STA interface >>> with MAC matching a PC connected to the wired port and effectively >>> have it be a transparent bridge between STA and PC. >>> >>> Has anyone attempted something like this before? >>> >>> Any interest in having this feature in the upstream kernel? >> >> You've just described what's done in several products and it is indeed >> useful. The main issue is supporting it can incur overhead so you may >> want to make it a compile-time option. > > I got some basic functionality working today with some > user-space bridging code I've already written for other purposes... > > Can you think of any reason (beyond a bit of performance) that > this should be in the kernel? Doing it in user space seems fine to start. All the examples I can think of are on minimal embedded platforms where taking the user-space hit is infeasible. All the wireless devices that are interesting can do this in h/w w/ only minimal kernel support (except for the vif setup). FWIW the overhead I was referring to is in the kernel. A many-to-1 mapping of STA<->AP can be more expensive to support than 1-1. But since you already support multi-sta you're already paying the price. > > My target hardware is fast enough that copying through user-space > at moderate (ie, fast as STA can go) speeds isn't too big of a deal, but > if someone wanted to run this on weak hardware, that might be reason > enough... It might also make it easier to filter our management frames > (EAPOL, etc), but we should be able to do that easily enough in user-space > with a small bit of work. Setting up and tearing down the sta's in response to wired traffic was always the fun part. Everything else was straightforward from what I can recall. -Sam -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
