Re: [PATCH net] net: dsa: flood multicast to CPU when slave has IFF_PROMISC

[Florian Fainelli <f.fainelli@gmail.com>]

On 4/21/22 15:42, Vladimir Oltean wrote:
> Certain DSA switches can eliminate flooding to the CPU when none of the
> ports have the IFF_ALLMULTI or IFF_PROMISC flags set. This is done by
> synthesizing a call to dsa_port_bridge_flags() for the CPU port, a call
> which normally comes from the bridge driver via switchdev.
> 
> The bridge port flags and IFF_PROMISC|IFF_ALLMULTI have slightly
> different semantics, and due to inattention/lack of proper testing, the
> IFF_PROMISC flag allows unknown unicast to be flooded to the CPU, but
> not unknown multicast.
> 
> This must be fixed by setting both BR_FLOOD (unicast) and BR_MCAST_FLOOD
> in the synthesized dsa_port_bridge_flags() call, since IFF_PROMISC means
> that packets should not be filtered regardless of their MAC DA.
> 
> Fixes: 7569459a52c9 ("net: dsa: manage flooding on the CPU ports")
> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
-- 
Florian