On Wed, Jul 16, 2025 at 11:35:50AM -0400, Joseph Huang wrote:
> 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@xxxxxxxxxx>
Reviewed-by: Ido Schimmel <idosch@xxxxxxxxxx>
