Re: [RFT] p54: implement multicast + arp req PS filter

[Christian Lamparter <chunkeey@googlemail.com>]

On Saturday 09 April 2011 22:23:51 Max Filippov wrote:
>>> So, I associated with that AP and obtained an IP address.
>> Just a question, that popped into my head: "Have you enabled PS?
>> either with "iw dev wlanX set power_save on" or
>> ?iwconfig wlanX power on?, because the filters may be restricted
>> to PSM.
> 
> I hadn't. LMAC API doc doesn't say that they're related.
> This time I ran tests both with "iwconfig wlan0 power on"
> and without it. Looks like PSM only makes kernel print
> "wlan0: detected beacon loss from AP - sending probe request".
> I see no other effect.
Well, that settles that.

>>[..]
> In the ARP case, when there's no other traffic on p54spi, all ARP requests
> are dropped. But if there's some egress traffic from p54spi, filter seems
> to work correctly: only ARP requests that match filter pass through.
"no other traffic" sounds like a the psm filter at work, have you disabled
it before starting the experiment?

or apply:

http://www.spinics.net/lists/linux-wireless/msg65488.html
(this patch makes the psm less aggressive by only sleeping
for one beacon interval at most [instead of listen_interval = 5]).

> In the multicast case filter seems to work correctly, but it treats broadcast
> as subject to that filtering too. By default only 01:00:5e:00:00:01 gets into
> priv->mc_maclist, so we miss all broadcasts.
ok, so we have to reserve a spot of ff:ff:ff:ff:ff:ff.

> These two filters seem to interfere:
> - if we set ARP filter and multicast filter without broadcast, we miss all
> ARPs if there's no egress traffic;
> - if we set ARP filter and multicast filter with broadcast, or don't set
> multicast filter at all we get all ARPs.
> 
> This effect does not depend on filter setup order.
interesting, well a unnamed [but trustworthy] source told us that ST identified
a problem with the arp/multicast filter some time ago, unfortunately I haven't
seen any updated p54spi firmwares lately. Maybe this sagred stuff works?
 
Thanks,
	Christian