RE: Read VLAN Tag in mac80211

["voncken" <cedric.voncken@acksys.fr>]

	The VLAN tag is moved from frame to the field skb->vlan_tci by the
input netdev. 

	In your case, if vlan_tci is always equal to 0, I think your driver
do not support the VLAN, or you need to enable it.
	You can have more information from netdev mailing list.

Cedric Voncken 


> -----Message d'origine-----
> De : linux-wireless-owner@vger.kernel.org [mailto:linux-wireless-
> owner@vger.kernel.org] De la part de Dani Camps
> Envoyé : vendredi 17 janvier 2014 17:27
> À : linux-wireless@vger.kernel.org
> Objet : Read VLAN Tag in mac80211
> 
> 
> 
> Dear all,
> 
> I am having trouble reading a VLAN tag inside mac80211. I believe the tag
is
> in the packet because I can see it in wireshark. This is a simple test
code that
> I am using in tx.c:
> 
> #include <linux/if_vlan.h>
> 
> ...
>         unsigned short TCI;
>         unsigned short id;
> ...
> 
> // Checking if VLAN tag is present
>         if(vlan_tx_tag_present(skb)){
>                 TCI = vlan_tx_tag_get (skb);
>                 id = TCI & VLAN_VID_MASK;
>                 printk ("VLAN detection:  Detected frame with VLAN ID = %x
\n", id);
>         }
>         else{
>                 printk ("VLAN detection:  No VLAN Tag detected but
skb->vlan_tci is
> %x \n", skb->vlan_tci);
>         }
> 
> The previous code always fails to enter the VLAN present case, and goes to
> the else condition printing a skb->vlan_tci value of zero, whereas I can
see in
> wireshark a frame with a VLAN tag and VLAN ID=1.
> 
> Can anyone help me figure out what I am missing here?
> 
> Best Regards
> 
> Daniel
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