Re: [PATCH iwl-next,v2 1/1] igc: Add wildcard rule support to ethtool NFC using Default Queue

[Kurt Kanzenbach]

On Thu Jun 19 2025, Song Yoong Siang wrote:
> Introduce support for a lowest priority wildcard (catch-all) rule in
> ethtool's Network Flow Classification (NFC) for the igc driver. The
> wildcard rule directs all unmatched network traffic, including traffic not
> captured by Receive Side Scaling (RSS), to a specified queue. This
> functionality utilizes the Default Queue feature available in I225/I226
> hardware.
>
> The implementation has been validated on Intel ADL-S systems with two
> back-to-back connected I226 network interfaces.
>
> Testing Procedure:
> 1. On the Device Under Test (DUT), verify the initial statistic:
>    $ ethtool -S enp1s0 | grep rx_q.*packets
>         rx_queue_0_packets: 0
>         rx_queue_1_packets: 0
>         rx_queue_2_packets: 0
>         rx_queue_3_packets: 0
>
> 2. From the Link Partner, send 10 ARP packets:
>    $ arping -c 10 -I enp170s0 169.254.1.2
>
> 3. On the DUT, verify the packet reception on Queue 0:
>    $ ethtool -S enp1s0 | grep rx_q.*packets
>         rx_queue_0_packets: 10
>         rx_queue_1_packets: 0
>         rx_queue_2_packets: 0
>         rx_queue_3_packets: 0
>
> 4. On the DUT, add a wildcard rule to route all packets to Queue 3:
>    $ sudo ethtool -N enp1s0 flow-type ether queue 3
>
> 5. From the Link Partner, send another 10 ARP packets:
>    $ arping -c 10 -I enp170s0 169.254.1.2
>
> 6. Now, packets are routed to Queue 3 by the wildcard (Default Queue) rule:
>    $ ethtool -S enp1s0 | grep rx_q.*packets
>         rx_queue_0_packets: 10
>         rx_queue_1_packets: 0
>         rx_queue_2_packets: 0
>         rx_queue_3_packets: 10
>
> 7. On the DUT, add a EtherType rule to route ARP packet to Queue 1:
>    $ sudo ethtool -N enp1s0 flow-type ether proto 0x0806 queue 1
>
> 8. From the Link Partner, send another 10 ARP packets:
>    $ arping -c 10 -I enp170s0 169.254.1.2
>
> 9. Now, packets are routed to Queue 1 by the EtherType rule because it is
>    higher priority than the wildcard (Default Queue) rule:
>    $ ethtool -S enp1s0 | grep rx_q.*packets
>         rx_queue_0_packets: 10
>         rx_queue_1_packets: 10
>         rx_queue_2_packets: 0
>         rx_queue_3_packets: 10
>
> 10. On the DUT, delete all the NFC rules:
>     $ sudo ethtool -N enp1s0 delete 63
>     $ sudo ethtool -N enp1s0 delete 64
>
> 11. From the Link Partner, send another 10 ARP packets:
>     $ arping -c 10 -I enp170s0 169.254.1.2
>
> 12. Now, packets are routed to Queue 0 because the value of Default Queue
>     is reset back to 0:
>     $ ethtool -S enp1s0 | grep rx_q.*packets
>          rx_queue_0_packets: 20
>          rx_queue_1_packets: 10
>          rx_queue_2_packets: 0
>          rx_queue_3_packets: 10
>
> Co-developed-by: Blanco Alcaine Hector <hector.blanco.alcaine@xxxxxxxxx>
> Signed-off-by: Blanco Alcaine Hector <hector.blanco.alcaine@xxxxxxxxx>
> Signed-off-by: Song Yoong Siang <yoong.siang.song@xxxxxxxxx>

Reviewed-by: Kurt Kanzenbach <kurt@xxxxxxxxxxxxx>

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