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Message-ID: <e1c1e7c114f0226b116d9549cea8e7a9@kapio-technology.com> Date: Sun, 17 Jul 2022 16:57:50 +0200 From: netdev@...io-technology.com To: Vladimir Oltean <olteanv@...il.com> Cc: Ido Schimmel <idosch@...dia.com>, davem@...emloft.net, kuba@...nel.org, netdev@...r.kernel.org, Andrew Lunn <andrew@...n.ch>, Vivien Didelot <vivien.didelot@...il.com>, Florian Fainelli <f.fainelli@...il.com>, Eric Dumazet <edumazet@...gle.com>, Paolo Abeni <pabeni@...hat.com>, Jiri Pirko <jiri@...nulli.us>, Ivan Vecera <ivecera@...hat.com>, Roopa Prabhu <roopa@...dia.com>, Nikolay Aleksandrov <razor@...ckwall.org>, Shuah Khan <shuah@...nel.org>, Daniel Borkmann <daniel@...earbox.net>, linux-kernel@...r.kernel.org, bridge@...ts.linux-foundation.org, linux-kselftest@...r.kernel.org Subject: Re: [PATCH v4 net-next 3/6] drivers: net: dsa: add locked fdb entry flag to drivers On 2022-07-17 15:59, Vladimir Oltean wrote: > On Sun, Jul 17, 2022 at 03:09:10PM +0200, netdev@...io-technology.com > wrote: >> On 2022-07-17 14:57, Vladimir Oltean wrote: >> > On Sun, Jul 17, 2022 at 02:21:47PM +0200, netdev@...io-technology.com >> > wrote: >> > > On 2022-07-13 14:39, Ido Schimmel wrote: >> > > > On Wed, Jul 13, 2022 at 09:09:58AM +0200, netdev@...io-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. > > 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. Maybe I am just trying to understand the problem you are posing, so afaics MAC addresses should be unique and having the same MAC address behind a locked port and a not-locked port seems like a mis-configuration regardless of vlan setup? As the zero-DPV entry only blocks the specific SA MAC on a specific vlan, which is behind a locked port, there shouldn't be any problem...? If the host behind a locked port starts sending on another vlan than where it got the first locked entry, another locked entry will occur, as the locked entries are MAC + vlan. > >> 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.
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