#!/bin/sh
# Cero3 Shaper
# A 3 bin tc_codel and ipv6 enabled shaping script for
# ethernet gateways

# Copyright (C) 2012 Michael D Taht
# GPLv2

# Compared to the complexity that debloat had become
# this cleanly shows a means of going from diffserv marking
# to prioritization using the current tools (ip(6)tables
# and tc. I note that the complexity of debloat exists for
# a reason, and it is expected that script is run first
# to setup various other parameters such as BQL and ethtool.
# (And that the debloat script has setup the other interfaces)

# You need to jiggle these parameters. Note limits are tuned towards a <10Mbit uplink <60Mbup down




. /usr/lib/aqm/functions.sh



ipt_setup() {

ipt -t mangle -N QOS_MARK_${IFACE}

ipt -t mangle -A QOS_MARK_${IFACE} -j MARK --set-mark 0x2
# You can go further with classification but...
ipt -t mangle -A QOS_MARK_${IFACE} -m dscp --dscp-class CS1 -j MARK --set-mark 0x3
ipt -t mangle -A QOS_MARK_${IFACE} -m dscp --dscp-class CS6 -j MARK --set-mark 0x1
ipt -t mangle -A QOS_MARK_${IFACE} -m dscp --dscp-class EF -j MARK --set-mark 0x1
ipt -t mangle -A QOS_MARK_${IFACE} -m dscp --dscp-class AF42 -j MARK --set-mark 0x1
ipt -t mangle -A QOS_MARK_${IFACE} -m tos  --tos Minimize-Delay -j MARK --set-mark 0x1

# and it might be a good idea to do it for udp tunnels too

# Turn it on. Preserve classification if already performed

ipt -t mangle -A POSTROUTING -o $DEV -m mark --mark 0x00 -g QOS_MARK_${IFACE} 
ipt -t mangle -A POSTROUTING -o $IFACE -m mark --mark 0x00 -g QOS_MARK_${IFACE} 

# The Syn optimization was nice but fq_codel does it for us
# ipt -t mangle -A PREROUTING -i s+ -p tcp -m tcp --tcp-flags SYN,RST,ACK SYN -j MARK --set-mark 0x01
# Not sure if this will work. Encapsulation is a problem period

ipt -t mangle -A PREROUTING -i vtun+ -p tcp -j MARK --set-mark 0x2 # tcp tunnels need ordering

# Emanating from router, do a little more optimization
# but don't bother with it too much. 

ipt -t mangle -A OUTPUT -p udp -m multiport --ports 123,53 -j DSCP --set-dscp-class AF42

#Not clear if the second line is needed
#ipt -t mangle -A OUTPUT -o $IFACE -g QOS_MARK_${IFACE}

}


# TC rules

egress() {

CEIL=${UPLINK}
PRIO_RATE=`expr $CEIL / 3` # Ceiling for prioirty
BE_RATE=`expr $CEIL / 6`   # Min for best effort
BK_RATE=`expr $CEIL / 6`   # Min for background
BE_CEIL=`expr $CEIL - 64`  # A little slop at the top

LQ="quantum `get_mtu $IFACE`"

$TC qdisc del dev $IFACE root 2> /dev/null
$TC qdisc add dev $IFACE root handle 1: ${STABSTRING} htb default 12
$TC class add dev $IFACE parent 1: classid 1:1 htb $LQ rate ${CEIL}kbit ceil ${CEIL}kbit $ADSLL
$TC class add dev $IFACE parent 1:1 classid 1:10 htb $LQ rate ${CEIL}kbit ceil ${CEIL}kbit prio 0 $ADSLL
$TC class add dev $IFACE parent 1:1 classid 1:11 htb $LQ rate 128kbit ceil ${PRIO_RATE}kbit prio 1 $ADSLL
$TC class add dev $IFACE parent 1:1 classid 1:12 htb $LQ rate ${BE_RATE}kbit ceil ${BE_CEIL}kbit prio 2 $ADSLL
$TC class add dev $IFACE parent 1:1 classid 1:13 htb $LQ rate ${BK_RATE}kbit ceil ${BE_CEIL}kbit prio 3 $ADSLL

$TC qdisc add dev $IFACE parent 1:11 handle 110: $QDISC limit 600 $NOECN `get_quantum 300` `get_flows ${PRIO_RATE}`
$TC qdisc add dev $IFACE parent 1:12 handle 120: $QDISC limit 600 $NOECN `get_quantum 300` `get_flows ${BE_RATE}`
$TC qdisc add dev $IFACE parent 1:13 handle 130: $QDISC limit 600 $NOECN `get_quantum 300` `get_flows ${BK_RATE}`

# Need a catchall rule

$TC filter add dev $IFACE parent 1:0 protocol all prio 999 u32 \
        match ip protocol 0 0x00 flowid 1:12  

# FIXME should probably change the filter here to do pre-nat
        
$TC filter add dev $IFACE parent 1:0 protocol ip prio 1 handle 1 fw classid 1:11
$TC filter add dev $IFACE parent 1:0 protocol ip prio 2 handle 2 fw classid 1:12
$TC filter add dev $IFACE parent 1:0 protocol ip prio 3 handle 3 fw classid 1:13

# ipv6 support. Note that the handle indicates the fw mark bucket that is looked for

$TC filter add dev $IFACE parent 1:0 protocol ipv6 prio 4 handle 1 fw classid 1:11
$TC filter add dev $IFACE parent 1:0 protocol ipv6 prio 5 handle 2 fw classid 1:12
$TC filter add dev $IFACE parent 1:0 protocol ipv6 prio 6 handle 3 fw classid 1:13

# Arp traffic

$TC filter add dev $IFACE parent 1:0 protocol arp prio 7 handle 1 fw classid 1:11

}

ingress() {

CEIL=$DOWNLINK
PRIO_RATE=`expr $CEIL / 3` # Ceiling for prioirty
BE_RATE=`expr $CEIL / 6`   # Min for best effort
BK_RATE=`expr $CEIL / 6`   # Min for background
BE_CEIL=`expr $CEIL - 64`  # A little slop at the top

LQ="quantum `get_mtu $IFACE`"

$TC qdisc del dev $IFACE handle ffff: ingress 2> /dev/null
$TC qdisc add dev $IFACE handle ffff: ingress
 
$TC qdisc del dev $DEV root  2> /dev/null
$TC qdisc add dev $DEV root handle 1: ${STABSTRING} htb default 12
$TC class add dev $DEV parent 1: classid 1:1 htb $LQ rate ${CEIL}kbit ceil ${CEIL}kbit
$TC class add dev $DEV parent 1:1 classid 1:10 htb $LQ rate ${CEIL}kbit ceil ${CEIL}kbit prio 0
$TC class add dev $DEV parent 1:1 classid 1:11 htb $LQ rate 32kbit ceil ${PRIO_RATE}kbit prio 1
$TC class add dev $DEV parent 1:1 classid 1:12 htb $LQ rate ${BE_RATE}kbit ceil ${BE_CEIL}kbit prio 2
$TC class add dev $DEV parent 1:1 classid 1:13 htb $LQ rate ${BK_RATE}kbit ceil ${BE_CEIL}kbit prio 3

# I'd prefer to use a pre-nat filter but that causes permutation...

$TC qdisc add dev $DEV parent 1:11 handle 110: $QDISC limit 1000 $ECN `get_quantum 500` `get_flows ${PRIO_RATE}`
$TC qdisc add dev $DEV parent 1:12 handle 120: $QDISC limit 1000 $ECN `get_quantum 1500` `get_flows ${BE_RATE}`
$TC qdisc add dev $DEV parent 1:13 handle 130: $QDISC limit 1000 $ECN `get_quantum 1500` `get_flows ${BK_RATE}`

diffserv $DEV

ifconfig $DEV up

# redirect all IP packets arriving in $IFACE to ifb0 

$TC filter add dev $IFACE parent ffff: protocol all prio 10 u32 \
  match u32 0 0 flowid 1:1 action mirred egress redirect dev $DEV

}

do_modules
ipt_setup
egress 
ingress

# References:
# This alternate shaper attempts to go for 1/u performance in a clever way
# http://git.coverfire.com/?p=linux-qos-scripts.git;a=blob;f=src-3tos.sh;hb=HEAD

# Comments
# This does the right thing with ipv6 traffic.
# It also tries to leverage diffserv to some sane extent. In particular,
# the 'priority' queue is limited to 33% of the total, so EF, and IMM traffic
# cannot starve other types. The rfc suggested 30%. 30% is probably
# a lot in today's world.

# Flaws
# Many!