From mboxrd@z Thu Jan  1 00:00:00 1970
From: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Subject: Re: [PATCH v2 net] net: Always untag vlan-tagged traffic on input.
Date: Mon, 29 Sep 2014 15:46:55 +0200
Message-ID: <542962CF.6000602@6wind.com>
References: <1407523333-31455-1-git-send-email-vyasevic@redhat.com> <54295449.7030203@6wind.com> <20140929130543.GB1839@nanopsycho.orion>
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Cc: Vladislav Yasevich <vyasevic@redhat.com>, netdev@vger.kernel.org,
	Patrick McHardy <kaber@trash.net>,
	Nithin Nayak Sujir <nsujir@broadcom.com>,
	Michael Chan <mchan@broadcom.com>
To: Jiri Pirko <jiri@resnulli.us>
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Le 29/09/2014 15:05, Jiri Pirko a =E9crit :
> Mon, Sep 29, 2014 at 02:44:57PM CEST, nicolas.dichtel@6wind.com wrote=
:
>> Le 08/08/2014 20:42, Vladislav Yasevich a =E9crit :
>> [snip]
>>>
>>> The patch attempt to fix this another way.  It moves the vlan heade=
r
>>> stipping code out of the vlan module and always builds it into the
>>> kernel network core.  This way, even if vlan is not supported on
>>> a virtualizatoin host, the virtual machines running on top of such
>>> host will still work with VLANs enabled.
>> After this patch (0d5501c1c828 ("net: Always untag vlan-tagged traff=
ic on
>> input.")), tcpdump will not be able to display the VLAN header on in=
put path.
>> Is this really intended?
>
> I assume you are talking about the case when CONFIG_VLAN_8021Q is "n"
> right? Because if it is "m" of "y" I see no change in the code.
Right.

>
> In case of CONFIG_VLAN_8021Q is "n" the only change is that for
> non-accelerated path, skb->vlan_tci is set and vlan header is strippe=
d.
> This makes the path same to accelerated path.
>
> tcpdump should be able to cope with skb->vlan_tci
My fault, I've tested with a quite old tcpdump version, with a recent o=
ne it
works perfectly!


Thank you,
Nicolas