On Sun, Jul 17, 2022 at 03:09:10PM +0200, netdev@xxxxxxxxxxxxxxxxxxxx wrote: > On 2022-07-17 14:57, Vladimir Oltean wrote: > > On Sun, Jul 17, 2022 at 02:21:47PM +0200, netdev@xxxxxxxxxxxxxxxxxxxx > > wrote: > > > On 2022-07-13 14:39, Ido Schimmel wrote: > > > > On Wed, Jul 13, 2022 at 09:09:58AM +0200, netdev@xxxxxxxxxxxxxxxxxxxx > > > > 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. I don't understand what you want to say by that. It will block all other packets with the same MAC SA that are classified to the same FID. In case of VLAN-aware bridges, the mv88e6xxx driver allocates a new FID for each VID (see mv88e6xxx_atu_new). In other words, if a locked port is VLAN-aware and has a pvid, then whatever the PVID may be, all ports in that same VLAN are still blocked in the same way. > Besides the fid will be zero with vlan unaware afaik, and all with > zero fid do not create locked entries. If by 0 you mean 1 (MV88E6XXX_FID_BRIDGED), then you are correct: ports with FID 0 (MV88E6XXX_FID_STANDALONE) should not create locked FDB entries, because they are, well, standalone and not bridged. Again I don't exactly see the relevance though.
