From 7c762e70c50b462fabe44a597e2a6c3e56c236c0 Mon Sep 17 00:00:00 2001
From: Vladimir Oltean <vladimir.oltean@nxp.com>
Date: Fri, 22 Apr 2022 01:42:22 +0300
Subject: [PATCH] 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 <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/dsa/slave.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
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);
--
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