netdev - RE: 802.1AD packets - Kernel changes ether type from 88A8 to 8100 on all packets.

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Message-ID: <BLU184-W5932FDD379FA1C7DFFA92FD0500@phx.gbl>
Date:	Tue, 15 Apr 2014 01:34:47 +0000
From:	Dennis Punjabi <linuxdev@...s.bz>
To:	Atzm Watanabe <atzm@...atosphere.co.jp>,
	Daniel Borkmann <dborkman@...hat.com>
CC:	Toshiaki Makita <toshiaki.makita1@...il.com>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: RE: 802.1AD packets - Kernel changes ether type from 88A8 to 8100
 on all packets.

>>> Hi.
>>>
>>> Though I'm not an expert with libpcap, I feel tcpdump sometimes shows a
>>> wrong vlan protocol (if vlan_tci is used).
>>>
>>> Maybe this topic has relevance?
>>>
>>> packet: deliver VLAN TPID to userspace
>>> http://marc.info/?l=linux-netdev&m=138728859001934&w=2
>>> http://marc.info/?l=linux-netdev&m=138728859601935&w=2
>>> http://marc.info/?l=linux-netdev&m=138728860101937&w=2
>>> http://marc.info/?l=linux-netdev&m=138728860601939&w=2
>>
>> The issue seems not to be in AF_PACKET as it just 'playes dumb' and propagates
>> what has been set in the skb as metadata to user space e.g., see ...
>
> Yes.
> Also I sent a small pull-request for libpcap via github to fix this
> issue about 2 weeks ago, but it is not pulled yet, still opened:
>
> https://github.com/the-tcpdump-group/libpcap/pull/346


Thanks Atzm and everyone for clarifying that and pointing me in the right direction.
Was not too sure where to begin looking.

I will apply the individual patches and try the 802.1AD filtering on the bridge.
Appreciate your help.

Best Regards,
Dennis
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