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

[Christian Lamparter <chunkeey@googlemail.com>]

On Sunday 10 April 2011 01:34:21 Max Filippov wrote:
> > > 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?
> 
> I ran tests first without "iwconfig wlan0 power on", rebooted and re-ran them
> with PSM. Didn't notice any difference.
ok. but still there's something positive about the result:
	ps no longer breaks everything ;)
	[Michael]

> And having ingress traffic only doesn't help ARPs to get through. They need egress to get in.
> In other words: I saw ingress packets in tcpdump, but no ARPs matching filter among them.
> But once packets start to go out of p54spi, ARPs matching filter get in. Looks very strange.
> 
> > > 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 for ff:ff:ff:ff:ff:ff.
> 
> But currently that cancels ARP filtering completely.

Ok, so we can't have both [atm] and we can't really choose between them either.
Or do you think it's worth salvaging the multicast filter for a [PATCH]?
> > > 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?
> 
> "sagred stuff" ?
yeah, it was a while ago... 
"p54spi (STLC4560) with Marvel XScale CPU (kernel 2.6.25.4)"
http://www.spinics.net/lists/linux-wireless/msg55967.html

AFAIK they have another p54spi firmware
"phy0: FW rev 2.19.0.0.A.14 Private - Softmac protocol 5.6"

Regards,
	Chr