How to set a CoS on a specific outbound packet?

Installing and Using OpenWrt
1

Hi,

I would like to know how to set a CoS on a specific outbound packet.

I've seen on others forums that they pass all traffic from the same VLAN (802.1q) on the same priority CoS (egress mapping). e.g : egress mapping "0:0 2:2 3:3 4:4 5:5 6:6 7:7 1:0 0:6" to set all outbound traffic on CoS 6.

But this method affects the upstream bandwidth, and the only solution is to set in nftables via a ".inlude file" a rule to reset all traffic on 0:1 via mangle_postrouting chain.

I'm searching a another way to do it, but without marking all traffic on CoS 6.
Just DHCP/DHCPv6/ARP/ICMPv6 on CoS 6.

If you've any ideas, it would be appreciate.

Thank you.

e.g VLAN egress :

config device
	option name 'eth0.1337'
	option type '8021q'
	option ifname 'eth0'
	option vid '1337'
        list egress_qos_mapping '0:0'
        list egress_qos_mapping '2:2'       
        list egress_qos_mapping '3:3'                                                                                                                   
        list egress_qos_mapping '4:4'
        list egress_qos_mapping '5:5'
        list egress_qos_mapping '6:6'
        list egress_qos_mapping '7:7'
        list egress_qos_mapping '1:0'
        list egress_qos_mapping '0:6'

e.g nftables mangle_postrouting rules :

nft add rule inet fw4 mangle_postrouting oifname "eth0.1337" counter meta priority set 0:1
nft add rule inet fw4 mangle_postrouting oifname "eth0.1337" udp dport 67 counter meta priority set 0:6
nft add rule inet fw4 mangle_postrouting oifname "eth0.1337" udp dport 547 counter meta priority set 0:6
nft add rule inet fw4 mangle_postrouting oifname "eth0.1337" ip protocol icmpv6 counter meta priority set 0:6