Hi Guenter,
On Jun 2, 2015, at 10:17 PM, Guenter Roeck li...@roeck-us.net wrote:
> On Tue, Jun 02, 2015 at 09:39:50PM -0400, Vivien Didelot wrote:
>> Guenter,
>>
>> On Jun 2, 2015, at 2:50 AM, Guenter Roeck li...@roeck-us.net 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.
>>
> Loading the 802.1q module has the same effect.
>
> I think this may be on purpose; it is telling the switch to accept
> packets with vid==0 (and untagged packets).
>
>> 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.
>>
> As far as I can see, the switch treats packets with vid==0 and untaged packets
> as unknown if VLAN support is enabled.
I am not sure about the untagged frames. But for tagged frames, the
documentation says that frames with vid 0 will be overridden with the port's
default VID.
> Anyway, sounds odd. Sure this isn't a configuration problem somethere ?
If I'm not mistaken, other drivers do that. e.g. Rocker deals with VID >= 1:
for (vid = 1; vid < VLAN_N_VID; vid++)
Maybe this VID overriding feature is what we want? But it doesn't look right to
me, even more since it is not exposed to the user.
Thanks,
-v
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