Re: [RFC 3/9] net: dsa: mv88e6xxx: add support for VTU ops

From: Vivien Didelot
Date: Tue Jun 02 2015 - 21:40:14 EST


Guenter,

On Jun 2, 2015, at 2:50 AM, Guenter Roeck linux@xxxxxxxxxxxx wrote:
> On 06/01/2015 06:27 PM, Vivien Didelot wrote:
>> + /* Bringing an interface up adds it to the VLAN 0. Ignore this. */
>> + if (!vid)
>> + return 0;
>> +
>
> Me puzzled ;-). I brought this and the fid question up before.
> No idea if my e-mail got lost or what happened.
>
> Can you explain why we don't need a configuration for vlan 0 ?

Sorry for late reply. Initially, when issuing "ip link set up dev swp0",
ndo_vlan_rx_add_vid was called to add the interface in the VLAN 0.

2 things happen here:

* this is inconsistent with the "bridge vlan" output which doesn't seem to
know about a VID 0;
* VID 0 seems special for this switch: if an ingressing frame has VID 0, the
tagged port will override the VID bits with the port default VID at egress.

Thanks,
-v
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