Anna Emese Nyiri wrote:

Extend cmsg_sender.c with a new option '-Q' to send SO_PRIORITY
ancillary data.

cmsg_so_priority.sh script added to validate SO_PRIORITY behavior 
by creating VLAN device with egress QoS mapping and testing packet
priorities using flower filters. Verify that packets with different
priorities are correctly matched and counted by filters for multiple
protocols and IP versions.

Suggested-by: Ido Schimmel <redacted>
Signed-off-by: Anna Emese Nyiri <redacted>

Reviewed-by: Willem de Bruijn <willemb@google.com>

+            ip netns exec $NS ./cmsg_sender -$i -Q $priority -d "${DELAY}" \
+	            -p $proto $TGT $PORT
+
+            pkts=$(tc -n $NS -j -s filter show dev dummy1 egress \
+                | jq ".[] | select(.options.handle == ${handle}) | \
+                .options.actions[0].stats.packets")
+            if [[ $pkts == 1 ]]; then
+                check_result 0
+            else
+                echo "prio $priority -Q: expected 1, got $pkts"
+                check_result 1
+            fi
+
+            ip netns exec $NS ./cmsg_sender -$i -P $priority -d "${DELAY}" \
+	            -p $proto $TGT $PORT

nit: delay is not used here. Neither txtime nor ts is set (and only
one packet is sent). It's harmless. No need to respin just for this.