Router custom QoS script: SimpleHFSCgamerscript.sh

SimpleHFSCgamerscript.sh is a shell script that will set up highly responsive QoS for a wired router with a single LAN on OpenWrt. It is important that you use a single ethernet device for your LAN, not a bridge with wifi, otherwise this script will not see all packets coming down from the internet as it only regulates ONE lan device and a bridge with ethernet and wifi contains two devices.

• log into your OpenWrt router
• cd /etc
• wget --no-check-certificates https://raw.githubusercontent.com/dlakelan/routerperf/master/SimpleHFSCgamerscript.sh
• chmod a+x /etc/SimpleHFSCgamerscript.sh
• wget --no-check-certificates https://raw.githubusercontent.com/dlakelan/routerperf/master/dscptag.sh
• edit SimpleHFSCgamerscript.sh to set your WAN and LAN interfaces, your network speeds, and the speed you reserve for your game (GAMEUP and GAMEDOWN)
• As of now the system will work with a combo wired+wifi router using a veth based design. If you want to use this set "USEVETHDOWN=yes" and "LANBR=br-lan" or change the name of your lan bridge if you have altered it from the OpenWrt default
• edit the script to include your gaming boxes in the set of ips that is prioritized for UDP:
• if you want to use netem also grab the files in tc-dists folder and place in /usr/lib/tc on your router

for ip4 in 192.168.1.111 192.168.1.222; do
    ipset add realtimeset4 "$ip4"
done

for ip6 in 2001:db8::1 2001:db8::2 ; do
    ipset add realtimeset6 "$ip6"
done

• You will need some packages, and I'm not sure what they all are, but you need packages for ipsets, hashlimits, the HFSC qdisc, veth modules, ip-full and probably a few others. If someone can give me a list, I will put it here.
• Preliminary package list suggests this is enough:
  • kmod-sched
  • ipset
  • kmod-ipt-ipset
  • ip-full
  • kmod-veth
  • iptables-mod-hashlimit
  • kmod-ipt-hashlimit
  • tc
  • iptables-mod-ipopt
  • iptables-mod-conntrack-extra
• edit the script to include bulk ports for torrent clients that you use
• edit dscptag.sh to add any rules you want to use for custom DSCP tagging
• If you are using the veth based method, then you need to add a custom OpenWrt interface for the veth device, do:

From the LUCI web interface:

• go to network > interfaces

• create an interface called "veth"

• under general setup > Protocol = unmanaged

• under physical settings > interface = lanveth

• under firewall settings > assign firewall-zone = LAN

Now, for testing, run the script

./SimpleHFSCgamerscript.sh

• To enable the script at all times, get the hotplug file:

cd /etc/hotplug.d/iface/
wget https://raw.githubusercontent.com/dlakelan/routerperf/master/13-SimpleHFSCGamerScriptHotplug

• Reboot

What this script does:

This script sets up a HFSC queue system on your WAN and LAN ethernet interfaces. It offers 5 classes of traffic. The most important class is 1:11 which is for use by realtime UDP traffic to and from a list of gaming machines which is set by you. Packets with DSCP tags CS5, CS6, CS7 will be sent to the realtime queue. Later when QFQ is available on OpenWrt we may enable sub-prioritizing these, such as making game packets more important than in-game VOIP or things like that.

The remaining classes 1:12, 1:13, 1:14, 1:15 are non-realtime but have different bandwidth and latency behavior when there is contention. You can edit the dscptag.sh script to tag DSCP on whatever packets you want to enter each class.

• CS4 goes to 1:12 which will have relatively low latency, good for interactive video chats, or casual gaming on a non-dedicated game machine
• CS3 or by default anything else goes to 1:13 which is for normal browsing
• CS2 goes to 1:14 which will tend to pause and allow other traffic to go ahead, this is useful for medium long downloads
• CS1 goes to 1:15 and has very poor bandwidth and long latency when there is contention with other classes. This is good for all-night torrenting etc.

All "normal" classes will use all available bandwidth if they are the only class using bandwidth. The realtime class will only use at most GAMEUP or GAMEDOWN.

In general for high speed connections the realtime bandwidth should be around 10-15% of your bandwidth or less... But when your connections are slow, we need them to be at least what the game actually needs. As a guideline, Call Of Duty used about 160kbps upstream and 320kbps downstream, so a good baseline is about double that each direction. By default we do something smart but you can adjust the script if needed, depending on the game you play.

This script will limit your download to at most 10x your upload, this is to avoid flooding your upload with ACK packets that compete with your gaming during large downloads by other devices. For slow speed connections below 3Mbps, it also does MSS clamping to encourage your TCP streams to use 540 byte packets to reduce the "lumpiness" of your queue thereby reducing jitter and dropped packets.

This should allow you to game on a shared line down to in the range of 700kbps upstream, however of course having higher speed connections will in general be better. A 3000kbps connection and above should have absolutely fluid gaming traffic with proper tuning of the settings. Testers have successfully played with fluid gaming on 16000kbps down / 830kbps up DSL lines.

Low Latency Daemon for x86 routers

On x86 routers using the intel pstate power saving system, you can prevent the cpu from going to very low power states by running the script lowlatencydaemon.lua as follows (can be done in /etc/rc.local)

lua lowlatencydaemon.lua

It has two tunables, starthr and endhr, which are the hours of the day that it should run at low latency, by default 6 and 22 so it is in low latency mode from 6am to 11pm. You can set 0 and 24 if you want low latency at all times.

Router performance analysis scripts (other scripts in this github)

This software collects data on a router running OpenWRT (or other linux) and creates a data file. It also includes scripts to transform that data file into a file containing a single JSON array, and some data analysis scripts in R.

The idea is we will eventually crowdsource a bunch of the data files, and create predictions for reliable SQM shaping bandwidth that each router supported by OpenWRT can handle. This portion of the project is no longer active.