netdev - Re: "wrong" ifindex on received VLAN tagged packet?

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Message-ID: <0448b3dd-d60f-b5f2-f833-fa63476f4a80@gmail.com>
Date:   Mon, 12 Mar 2018 13:26:15 -0700
From:   David Ahern <dsahern@...il.com>
To:     Lawrence Kreeger <lkreeger@...il.com>
Cc:     netdev@...r.kernel.org
Subject: Re: "wrong" ifindex on received VLAN tagged packet?

On 3/6/18 5:27 PM, Lawrence Kreeger wrote:
> Using ETH_P_ALL instead of ETH_P_802_2, is causing mstpd to get 3
> copies of the same BPDU.  One from eth0, one from eth0.100, and
> another from vlan100 (the bridge).
> mstpd will drop the one from vlan100, but since there is also an
> instance of spanning tree running on the native VLAN, there is now no
> way to differentiate BPDUs coming in
> tagged vs untagged because they all show up with eth0.  So, there
> isn't some kernel knob to get the BPDUs to only come from eth0.100?

not that I am aware of. You could bind your socket or program to
eth0.100, but I suspect you actually have more than the one vlan
interface coming into the bridge that you want to snoop.