Re: [PATCH net v2] net: mscc: ocelot: Fix multicast to the CPU port

[Jakub Kicinski]

On Tue, 19 Jan 2021 16:46:01 +0000 Vladimir Oltean wrote:
> On Tue, Jan 19, 2021 at 03:06:38PM +0100, Alban Bedel wrote:
> > Multicast entries in the MAC table use the high bits of the MAC
> > address to encode the ports that should get the packets. But this port
> > mask does not work for the CPU port, to receive these packets on the
> > CPU port the MAC_CPU_COPY flag must be set.
> > 
> > Because of this IPv6 was effectively not working because neighbor
> > solicitations were never received. This was not apparent before commit
> > 9403c158 (net: mscc: ocelot: support IPv4, IPv6 and plain Ethernet mdb
> > entries) as the IPv6 entries were broken so all incoming IPv6
> > multicast was then treated as unknown and flooded on all ports.
> > 
> > To fix this problem rework the ocelot_mact_learn() to set the
> > MAC_CPU_COPY flag when a multicast entry that target the CPU port is
> > added. For this we have to read back the ports endcoded in the pseudo
> > MAC address by the caller. It is not a very nice design but that avoid
> > changing the callers and should make backporting easier.
> > 
> > Signed-off-by: Alban Bedel <alban.bedel@xxxxxxxx>
> > Fixes: 9403c158b872 ("net: mscc: ocelot: support IPv4, IPv6 and plain Ethernet mdb entries")
> > 
> > ---  
> 
> Reviewed-by: Vladimir Oltean <vladimir.oltean@xxxxxxx>
> Tested-by: Vladimir Oltean <vladimir.oltean@xxxxxxx>

Applied, thanks!