Messages in this thread | | | Date | Sun, 17 Jul 2022 15:09:10 +0200 | From | netdev@kapio-te ... | Subject | Re: [PATCH v4 net-next 3/6] drivers: net: dsa: add locked fdb entry flag to drivers |
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On 2022-07-17 14:57, Vladimir Oltean wrote: > On Sun, Jul 17, 2022 at 02:21:47PM +0200, netdev@kapio-technology.com > wrote: >> On 2022-07-13 14:39, Ido Schimmel wrote: >> > On Wed, Jul 13, 2022 at 09:09:58AM +0200, netdev@kapio-technology.com >> > wrote: >> >> > >> > What are "Storm Prevention" and "zero-DPV" FDB entries? >> >> They are both FDB entries that at the HW level drops all packets >> having a >> specific SA, thus using minimum resources. >> (thus the name "Storm Prevention" aka, protection against DOS attacks. >> We >> must remember that we operate with CPU based learning.) > > DPV means Destination Port Vector, and an ATU entry with a DPV of 0 > essentially means a FDB entry pointing nowhere, so it will drop the > packet. That's a slight problem with Hans' implementation, the bridge > thinks that the locked FDB entry belongs to port X, but in reality it > matches on all bridged ports (since it matches by FID). FID allocation > in mv88e6xxx is slightly strange, all VLAN-unaware bridge ports, > belonging to any bridge, share the same FID, so the FDB databases are > not exactly isolated from each other.
But if the locked port is vlan aware and has a pvid, it should not block other ports. Besides the fid will be zero with vlan unaware afaik, and all with zero fid do not create locked entries.
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