Re: [PATCH net-next v3] selftests: net: csum: filter packets by source address and port

[Simon Horman <horms@kernel.org>]

On Tue, Sep 08, 2026 at 11:54:29AM -0400, Willem de Bruijn wrote:
> From: Willem de Bruijn <willemb@google.com>
> 
> Add source address and port verification in recv_verify_packet_* and
> recv_udp: non-matching packets are skipped.
> 
> The receiver reads from PF_PACKET and UDP sockets to verify incoming
> packets to test hardware checksum offload. It did not validate the
> packet source address or source port.
> 
> During tests expecting an invalid checksum (-E) or zero checksum (-Z),
> background packets can fail the test.
> 
> For -Z, build_packet_udp chooses a specific source port that causes
> the checksum to sum to zero. When running in receive-only mode (-R),
> call build_packet in do_rx to compute the expected source port so
> that source port filtering can be applied to -Z as well.
> 
> Also
> - add an inter-packet delay to avoid drops from bursts.
> - remove a comment that is no longer correct.
> 
> Fixes: 91a7de85600d ("selftests/net: add csum offload test")
> Signed-off-by: Willem de Bruijn <willemb@google.com>
> 
> ---
> 
> Changes
>   v2 -> v3
>     - also fix same issue for zero checksum:
>       calculate expected src_port by calling build_packet on rx side
>   v1 -> v2
>     - also check udp socket, with recvfrom
> 
> v2: https://lore.kernel.org/netdev/20260904030624.3833721-1-willemdebruijn.kernel@gmail.com/
> v1: https://lore.kernel.org/netdev/20260831210128.1359978-1-willemdebruijn.kernel@gmail.com/

Reviewed-by: Simon Horman <horms@kernel.org>