An nftables ruleset for OpenWrt's firewall4 for dynamically setting DSCP packet marks (this only works in OpenWrt 22.03 and above).
This should be used in conjunction with layer-cake SQM queue with ctinfo configured to restore DSCP on the device ingress. The nft-dscpclassify rules use the last 8 bits of the conntrack mark (0x000000ff).
The nftables rule file must be placed in:
"/etc/nftables.d"
The SQM queue setup script 'layer_cake_ct.qos' must be placed in:
"/usr/lib/sqm"
Your SQM config must use the new 'layer_cake_ct.qos' queue setup script.
Tested working SQM config for the script:
| Config parameter | Value |
|---|---|
| qdisc_advanced | '1' |
| squash_dscp | '0' |
| squash_ingress | '0' |
| qdisc_really_really_advanced | '1' |
| iqdisc_opts | 'nat dual-dsthost ingress diffserv4' |
| eqdisc_opts | 'nat dual-srchost ack-filter diffserv4' |
| script | 'layer_cake_ct.qos' |