фильтр управления трафиком на основе потоков (flow based traffic control filter)
Примечание (Note)
As stated above where applicable, matches of a certain layer
implicitly depend on the matches of the next lower layer.
Precisely, layer one and two matches (indev, dst_mac and
src_mac) have no dependency, MPLS and layer three matches (mpls,
mpls_label, mpls_tc, mpls_bos, mpls_ttl, ip_proto, dst_ip,
src_ip, arp_tip, arp_sip, arp_op, arp_tha, arp_sha and ip_flags)
depend on the protocol option of tc filter, layer four port
matches (dst_port and src_port) depend on ip_proto being set to
tcp, udp or sctp, and finally ICMP matches (code and type) depend
on ip_proto being set to icmp or icmpv6.
There can be only used one mask per one prio. If user needs to
specify different mask, he has to use different prio.
