Messages in this thread | | | From | DENG Qingfang <> | Date | Fri, 30 Jul 2021 23:45:41 +0800 | Subject | Re: [RFC net-next 2/2] net: dsa: mt7530: trap packets from standalone ports to the CPU |
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On Fri, Jul 30, 2021 at 12:50 AM Vladimir Oltean <olteanv@gmail.com> wrote: > I have the MT7621 GSW, and sadly this reference manual isn't the best in > explaining what is and what is not possible. For example, I am still not > clear what is meant by "VID1" and "VID0". Is "VID1" the inner (customer) > VLAN tag, and "VID0" the outer (service) VLAN tag, or "VID1" means the > actual VLAN ID 1? > > And the bits 3:1 of VAWD1 (VLAN table access register) indicate a FID > field per VLAN. I cannot find the piece that you quoted in this manual. > But what I expect to happen for a Transparent Port is that the packets > are always classified to that port's PVID, and the VLAN Table is looked > up with that PVID. There, it will find the FID, which this driver > currently always configures as zero. In my manual's description, in the > "Transparent Port" chapter, it does explicitly say: > > VID0 and VID1 will store PVID as the default VID which is used > to look up the VLAN table. > > So I get the impression that the phrase "the VLAN table is not applicable" > is not quite correct, but I might be wrong...
Alright, I think I've made some progress. In the current code, we only use two combinations to toggle user ports' VLAN awareness: one is PCR.PORT_VLAN set to port matrix mode with PVC.VLAN_ATTR set to transparent port, the other is PCR.PORT_VLAN set to security mode with PVC.VLAN_ATTR set to user port.
It turns out that only PVC.VLAN_ATTR contributes to VLAN awareness. Port matrix mode just skips the VLAN table lookup. The reference manual is somehow misleading when describing PORT_VLAN modes (See Page 17 of MT7531 Reference Manual, available at http://wiki.banana-pi.org/Banana_Pi_BPI-R64#Resources). It states that PORT_MEM (VLAN port member) is used for destination if the VLAN table lookup hits, but actually it uses **PORT_MEM & PORT_MATRIX** (bitwise AND of VLAN port member and port matrix) instead, which means we can have two or more separate VLAN-aware bridges with the same PVID and traffic won't leak between them.
So I came up with a solution: Set PORT_VLAN to fallback mode when in VLAN-unaware mode, this way, even VLAN-unaware bridges will use independent VLAN filtering. Then assign all standalone ports to a reserved VLAN.
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