Do not offload IGMP/MLD messages as it could lead to IGMP/MLD Reports being unintentionally flooded to Hosts. Instead, let the bridge decide where to send these IGMP/MLD messages. Consider the case where the local host is sending out reports in response to a remote querier like the following: mcast-listener-process (IP_ADD_MEMBERSHIP) \ br0 / \ swp1 swp2 | | QUERIER SOME-OTHER-HOST In the above setup, br0 will want to br_forward() reports for mcast-listener-process's group(s) via swp1 to QUERIER; but since the source hwdom is 0, the report is eligible for tx offloading, and is flooded by hardware to both swp1 and swp2, reaching SOME-OTHER-HOST as well. (Example and illustration provided by Tobias.) Fixes: 472111920f1c ("net: bridge: switchdev: allow the TX data plane forwarding to be offloaded") Signed-off-by: Joseph Huang --- v1: https://lore.kernel.org/netdev/20250701193639.836027-1-Joseph.Huang@garmin.com/ v2: https://lore.kernel.org/netdev/20250714150101.1168368-1-Joseph.Huang@garmin.com/ Updated commit message. v3: Return early if it's an IGMP/MLD packet. --- net/bridge/br_switchdev.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/bridge/br_switchdev.c b/net/bridge/br_switchdev.c index 95d7355a0407..9a910cf0256e 100644 --- a/net/bridge/br_switchdev.c +++ b/net/bridge/br_switchdev.c @@ -17,6 +17,9 @@ static bool nbp_switchdev_can_offload_tx_fwd(const struct net_bridge_port *p, if (!static_branch_unlikely(&br_switchdev_tx_fwd_offload)) return false; + if (br_multicast_igmp_type(skb)) + return false; + return (p->flags & BR_TX_FWD_OFFLOAD) && (p->hwdom != BR_INPUT_SKB_CB(skb)->src_hwdom); } -- 2.50.1