5.15-stable review patch. If anyone has any objections, please let me know.
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From: Joseph Huang Joseph.Huang@garmin.com
[ Upstream commit 683dc24da8bf199bb7446e445ad7f801c79a550e ]
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 Joseph.Huang@garmin.com Acked-by: Nikolay Aleksandrov razor@blackwall.org Reviewed-by: Ido Schimmel idosch@nvidia.com Link: https://patch.msgid.link/20250716153551.1830255-1-Joseph.Huang@garmin.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 6bf518d78f029..44ae2068045b1 100644 --- a/net/bridge/br_switchdev.c +++ b/net/bridge/br_switchdev.c @@ -16,6 +16,9 @@ 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); }