From: Vladimir Oltean Date: Thu, 21 Apr 2022 22:42:22 +0000 (+0300) Subject: net: dsa: flood multicast to CPU when slave has IFF_PROMISC X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=7c762e70c50b462fabe44a597e2a6c3e56c236c0;p=linux.git net: dsa: flood multicast to CPU when slave has IFF_PROMISC 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 Reviewed-by: Florian Fainelli Signed-off-by: David S. Miller --- diff --git a/net/dsa/slave.c b/net/dsa/slave.c index 41c69a6e7854a..8022d50584db7 100644 --- a/net/dsa/slave.c +++ b/net/dsa/slave.c @@ -285,7 +285,7 @@ static void dsa_port_manage_cpu_flood(struct dsa_port *dp) if (other_dp->slave->flags & IFF_ALLMULTI) flags.val |= BR_MCAST_FLOOD; if (other_dp->slave->flags & IFF_PROMISC) - flags.val |= BR_FLOOD; + flags.val |= BR_FLOOD | BR_MCAST_FLOOD; } err = dsa_port_pre_bridge_flags(dp, flags, NULL);