#!/bin/bash

# Traffic Shaper -- with inspiration from Wondershaper/LARTC Cookbooks

TC=/sbin/tc

# desired traffic speed
TOPLAYERS=5120

# Interface to use
DEV=eth0

# The port that squid uses
CACHEPORTS="2235 80"

if [ "$1" = "status" ]
then
	$TC -s qdisc ls dev $DEV
	$TC -s class ls dev $DEV
	exit
fi


# clean existing down- and uplink qdiscs, hide errors
$TC qdisc del dev $DEV root    2> /dev/null > /dev/null
$TC qdisc del dev $DEV ingress 2> /dev/null > /dev/null

if [ "$1" = "stop" ] 
then 
	exit
fi


#
# Uplink
#

#
# Disciplines
#

# install root HTB

$TC qdisc add dev $DEV root handle 1: htb default 20

# set the maximum throughput to our definition (1:1)
$TC class add dev $DEV parent 1: classid 1:1 htb rate $[$TOPLAYERS+2048]kbit \
    burst 6k

# this is the highest priority traffic for interactive work (1:10)
$TC class add dev $DEV parent 1:1 classid 1:10 htb rate $[$TOPLAYERS+2048]kbit \
    burst 6k prio 1

# bulk and default class (1:20) is the default class
$TC class add dev $DEV parent 1:1 classid 1:20 htb rate $[$TOPLAYERS+1024]kbit \
    burst 6k prio 2

# the long-term traffic hogs are in this class (1:30) and get the lowest rate
$TC class add dev $DEV parent 1:1 classid 1:30 htb rate ${TOPLAYERS}kbit \
    burst 6k prio 2

# stochatic fairness will try to service all consumers of our network
$TC qdisc add dev $DEV parent 1:10 handle 10: sfq perturb 10
$TC qdisc add dev $DEV parent 1:20 handle 20: sfq perturb 10
$TC qdisc add dev $DEV parent 1:30 handle 30: sfq perturb 10

#
# Filters
#

# TOS Minimum Delay
$TC filter add dev $DEV parent 1:0 protocol ip prio 10 u32 \
    match ip tos 0x10 0xff  flowid 1:10

# ICMP (ip protocol 1) in the interactive class 1:10
$TC filter add dev $DEV parent 1:0 protocol ip prio 10 u32 \
        match ip protocol 1 0xff flowid 1:10

# prioritize ACK packets
$TC filter add dev $DEV parent 1: protocol ip prio 10 u32 \
    match ip protocol 6 0xff \
    match u8 0x05 0x0f at 0 \
    match u16 0x0000 0xffc0 at 2 \
    match u8 0x10 0xff at 33 \
    flowid 1:10

# prioritize small packets (<64 bytes)
tc filter add dev $DEV parent 1: protocol ip prio 12 u32 \
    match ip protocol 6 0xff \
    match u8 0x05 0x0f at 0 \
    match u16 0x0000 0xffc0 at 2 \
    flowid 1:10

# give cache traffic a slower time
for a in $CACHEPORTS
do
  $TC filter add dev $DEV parent 1: protocol ip prio 15 u32 \
      match ip sport $a 0xffff flowid 1:30
done

# rest is 'non-interactive' ie 'bulk' and ends up in 1:20
$TC filter add dev $DEV parent 1: protocol ip prio 18 u32 \
    match ip dst 0.0.0.0/0 flowid 1:20