On 7/29/2020 7:49 AM, Gaube, Marvin (THSE-TL1) wrote:
> Hello,
> I just tried a VLAN-enabled bridge.
> All ingress packets definitely have the 802.1q-Tag on CPU ingress,
> double-checked that. Tried again with VLAN21-Tagged frames coming in the
> physical port.
> It seems that the bridge also handles all packets from lan1 as untagged. When
> I add lan1 to the bridge, the following happens:
>
> If lan1 has (only) VLAN 21 tagged on the bridge, no packet appears.
> As soon as I add an untagged/pvid VLAN to lan1 on the bridge, all packets
> appear on the bridge with whichever VLAN I added.
> I checked simultaneously with the CPU Ingress-Port (eth1), the same packets
> had Ethertype 8100 with VLAN 21 when they entered CPU.
Can you share the commands you use to set-up your bridge with VLAN
filtering and VLAN21 added to the VLAN database of the bridge for lan1?
>
> With Switchport 1, the physical switch port of the KSZ is meant.
OK.
>
> About the last thing: VLAN tagged frames are definitively passed to the CPU.
> If I "tcpdump -xx" onto eth1, I see for example "(12 byte MAC) 8100 0015 86dd
> (IPv6-Payload)". The tail tag is also visible.
> Exactly the same frame appears on lan1 as "(12 byte MAC) 86dd
> (IPv6-Payload)", so the 802.1q-Header is present on CPU ingress.
> Therefore the VLAN tag probably is lost between eth1 (Ingress) and the
> respective DSA-Interface, and is not filtered on the KSZ9477.
What Ethernet controller driver is eth1, does it support VLAN receive
filter (NETIF_F_HW_VLAN_CTAG_FILTER)?
>
> Best Regards
> Marvin Gaube
>
> -----Ursprüngliche Nachricht-----
> Von: Florian Fainelli <[email protected]>
> Gesendet: Mittwoch, 29. Juli 2020 15:48
> An: Gaube, Marvin (THSE-TL1) <[email protected]>; Woojung Huh
> <[email protected]>; Microchip Linux Driver Support
> <[email protected]>
> Cc: [email protected]
> Betreff: Re: PROBLEM: (DSA/Microchip): 802.1Q-Header lost on KSZ9477-DSA
> ingress without bridge
>
>
>
> On 7/28/2020 11:05 PM, Gaube, Marvin (THSE-TL1) wrote:
>> Summary: 802.1Q-Header lost on KSZ9477-DSA ingress without bridge
>> Keywords: networking, dsa, microchip, 802.1q, vlan Full description:
>>
>> Hello,
>> we're trying to get 802.1Q-Tagged Ethernet Frames through an KSZ9477
>> DSA-enabled switch without creating a bridge on the kernel side.
>
> Does it work if you have a bridge that is VLAN aware though? If it does, this
> would suggest that the default VLAN behavior without a bridge is too
> restrictive and needs changing.
>
>> Following setup:
>> Switchport 1 <-- KSZ9477 --> eth1 (CPU-Port) <---> lan1
>
> This representation is confusing, is switchport 1 a network device or is this
> meant to be physical switch port number of 1 of the KSZ9477?
>
>>
>> No bridge is configured, only the interface directly. Untagged packets are
>> working without problems. The Switch uses the ksz9477-DSA-Driver with
>> Tail-Tagging ("DSA_TAG_PROTO_KSZ9477").
>> When sending packets with 802.1Q-Header (tagged VLAN) into the Switchport, I
>> see them including the 802.1Q-Header on eth1.
>> They also appear on lan1, but with the 802.1Q-Header missing.
>> When I create an VLAN-Interface over lan1 (e.g. lan1.21), nothing arrives
>> there.
>> The other way around, everything works fine: Packets transmitted into
>> lan1.21 are appearing in 802.1Q-VLAN 21 on the Switchport 1.
>>
>> I assume that is not the intended behavior.
>> I haven't found an obvious reason for this behavior yet, but I suspect the
>> VLAN-Header gets stripped of anywhere around "dsa_switch_rcv" in
>> net/dsa/dsa.c or "ksz9477_rcv" in net/dsa/tag_ksz.c.
>
> Not sure how though, ksz9477_rcv() only removes the trail tag, this should
> leave any header intact. It seems to me that the switch is incorrectly
> configured and is not VLAN aware at all, nor passing VLAN tagged frames
> through on ingress to CPU when it should.
> --
> Florian
>
> ________________________________
>
> Tesat-Spacecom GmbH & Co. KG
> Sitz: Backnang; Registergericht: Amtsgericht Stuttgart HRA 270977
> Persoenlich haftender Gesellschafter: Tesat-Spacecom Geschaeftsfuehrungs GmbH;
> Sitz: Backnang; Registergericht: Amtsgericht Stuttgart HRB 271658;
> Geschaeftsfuehrung: Dr. Marc Steckling, Kerstin Basche, Ralf Zimmermann
>
> [banner]
>
--
Florian
