igc: Add wildcard rule support to ethtool NFC using Default Queue

igc: Add wildcard rule support to ethtool NFC using Default Queue

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

Reviewed-by: Kurt Kanzenbach <kurt@linutronix.de>
Co-developed-by: Blanco Alcaine Hector <hector.blanco.alcaine@intel.com>
Signed-off-by: Blanco Alcaine Hector <hector.blanco.alcaine@intel.com>
Signed-off-by: Song Yoong Siang <yoong.siang.song@intel.com>
Tested-by: Mor Bar-Gabay <morx.bar.gabay@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>