#!/bin/bash

### basic settings - speed in bits/sec
WAN_INTF=eth0
WAN_UP_SPEED=2800000
WAN_DOWN_SPEED=28000000

### advanced settings
TQDISC=fq_codel

# Dave Taht's recommendation:
#   less than 40mbit: 300
#   otherwise: 1514
FQ_CODEL_QUANTUM_UP=300
FQ_CODEL_QUANTUM_DOWN=300

# Dave Taht's recommendation:
#   less than 3mbit: 15ms
#   otherwise: 5ms
FQ_CODEL_TARGET_UP=15ms
FQ_CODEL_TARGET_DOWN=5ms

# Dave Taht's recommendation:
#   less than 40mbit: 1500
#   otherwise: higher (e.g., 8000 or higher for 100mbit etc.)
HTB_QUANTUM_UP=1500
HTB_QUANTUM_DOWN=1500

### configurable knobs end here

TQDISC_OPTS_UP=
TQDISC_OPTS_DOWN=
if [ "$TQDISC" == fq_codel ]; then
    TQDISC_OPTS_UP+="quantum $FQ_CODEL_QUANTUM_UP "
    TQDISC_OPTS_UP+="target $FQ_CODEL_TARGET_UP "
    TQDISC_OPTS_DOWN+="quantum $FQ_CODEL_QUANTUM_DOWN "
    TQDISC_OPTS_DOWN+="target $FQ_CODEL_TARGET_DOWN "
fi

WAN_IFB="ifb_${WAN_INTF}"
TC=/sbin/tc
IP=/sbin/ip

$TC qdisc del dev $WAN_INTF root >/dev/null 2>&1
$TC qdisc del dev $WAN_INTF ingress >/dev/null 2>&1
$TC qdisc del dev $WAN_IFB root >/dev/null 2>&1

[ "$1" == clear ] && exit 0

$TC qdisc add dev $WAN_INTF root handle 1: htb default 10
$TC class add dev $WAN_INTF parent 1: classid 1:1 \
    htb quantum $HTB_QUANTUM_UP \
    rate $WAN_UP_SPEED ceil $WAN_UP_SPEED
$TC class add dev $WAN_INTF parent 1:1 classid 1:10 \
    htb quantum $HTB_QUANTUM_UP \
    rate $WAN_UP_SPEED ceil $WAN_UP_SPEED
$TC qdisc add dev $WAN_INTF parent 1:10 handle 100: $TQDISC $TQDISC_OPTS_UP

$IP link add $WAN_IFB type ifb >/dev/null 2>&1
$TC qdisc add dev $WAN_IFB root handle 1: htb default 10
$TC class add dev $WAN_IFB parent 1: classid 1:1 \
    htb quantum $HTB_QUANTUM_DOWN \
    rate $WAN_DOWN_SPEED ceil $WAN_DOWN_SPEED
$TC class add dev $WAN_IFB parent 1:1 classid 1:10 \
    htb quantum $HTB_QUANTUM_DOWN \
    rate $WAN_DOWN_SPEED ceil $WAN_DOWN_SPEED
$TC qdisc add dev $WAN_IFB parent 1:10 handle 100: $TQDISC $TQDISC_OPTS_DOWN

$IP link set $WAN_IFB up
$TC qdisc add dev $WAN_INTF handle ffff: ingress
$TC filter add dev $WAN_INTF parent ffff: \
    protocol all prio 10 u32 match u32 0 0 flowid 1:1 \
    action mirred egress redirect dev $WAN_IFB