+linux kernels above 4.2 ("Flower" classifier required).
+The kernel support can be checked with this command::
+
+ zcat /proc/config.gz | ( grep 'CLS_FLOWER=' || echo 'not supported' ) |
+ tee -a /dev/stderr | grep -q '=m' &&
+ lsmod | ( grep cls_flower || echo 'try modprobe cls_flower' )
+
+Supported items: