Re: [PATCH] vlan_dev: VLAN 0 should be treated as "no vlan tag" (802.1p packet)

[Pedro Garcia Pelaez <pedro@dondevamos.com>]

On Wed, 16 Jun 2010 10:49:27 +0200, Pedro Garcia
<pedro.netdev@dondevamos.com> wrote:
> On Mon, 14 Jun 2010 21:12:52 +0200, Eric Dumazet
<eric.dumazet@gmail.com>
> wrote:
>> Le lundi 14 juin 2010 à 19:11 +0200, Patrick McHardy a écrit :
>>> Ben Hutchings wrote:
>>> > On Mon, 2010-06-14 at 18:49 +0200, Pedro Garcia wrote:
>>> >   
>>> >> On Sun, 13 Jun 2010 22:56:30 +0100, Ben Hutchings
>>> >> <bhutchings@solarflare.com> wrote:
>>> >>     
>>> >>> I have no particular opinion on this change, but you need to read
>>> >>> and
>>> >>> follow Documentation/SubmittingPatches.
>>> >>>
>>> >>> Ben.
>>> >>>       
>>> >> Sorry, first kernel patch, and I did not know about it. I resubmit
>>> >> with
>>> >> the correct style / format:
>>> >>     
>>> > [...]
>>> >
>>> > Sorry, no you haven't.
>>> >
>>> > - Networking changes go through David Miller's net-next-2.6 tree so
>>> > you
>>> > need to use that as the baseline, not 2.6.26
>>> > - Patches should be applicable with -p1, not -p0 (so if you use
diff,
>>> > you should run it from one directory level up)
>>> > - The patch was word-wrapped
>>> 
>>> Additionally:
>>> 
>>> - please use the proper comment style, meaning each line begins
>>>   with a '*'
>>> 
>>> - the pr_debug statements may be useful for debugging, but are
>>>   a bit excessive for the final version
>>> 
>>> - + /* 2010-06-13: Pedro Garcia
>>> 
>>>    We have changelogs for this, simply explaining what the code
>>>    does is enough.
>>> 
>>> - Please CC the maintainer (which is me)
>>> --
>> 
>> Pedro, we have two kind of vlan setups :
>> 
>> accelerated and non accelerated ones.
>> 
>> Your patch address non accelated ones only, since you only touch
>> vlan_skb_recv()
>> 
>> Accelerated vlan can follow these paths :
>> 
>> 1) NAPI devices
>> 
>> vlan_gro_receive() -> vlan_gro_common()
>> 
>> 2) non NAPI devices
>> 
>> __vlan_hwaccel_rx() 
>> 
>> So you might also patch __vlan_hwaccel_rx() and vlan_gro_common()
>> 
>> Please merge following bits to your patch submission :
>> 
>> http://kerneltrap.org/mailarchive/linux-netdev/2010/5/23/6277868
>> 
>> 
>> Good luck for your first patch !
> 
> Here it is again. I added the modifications in
> http://kerneltrap.org/mailarchive/linux-netdev/2010/5/23/6277868 for HW
> accelerated incoming packets (it did not apply cleanly on the last
version
> of
> the kernel, so I applied manually). Now, if the VLAN 0 is not explicitly
> created by the user, VLAN 0 packets will be treated as no VLAN (802.1p
> packets), instead of dropping them.
> 
> The patch is now for two files: vlan_core (accel) and vlan_dev (non
accel)
> 
> I can not test on HW accelerated devices, so if someone can check it I
> will appreciate (even though in the thread above it looked like yes).
For
> non accel I tessted in 2.6.26. Now the patch is for
> net-next-2.6, and it compiles OK, but I a have to setup a test
environment
> to check it is still OK (should, but better to test).
> 

I tested the pacth under net-next-2.6, and it OOPSed the kernel (worked
under 2.6.26 but not under 2.6.35). I have found why and solved it, but
now, to my surprise, it only works when I leave the interface in
promiscuous mode.

After a lot of debugging, looks like the skb does not even arrive to
__netif_receive_skb, unless in promiscuous mode. Under what circunstances
could this happen?

Pedro