Driver for the intermediate queue device
Jiri Fojtasek jiri.fojtasek(somewhere at)hlohovec.net, Last update: 30.3. 2004

Fixed bug with spinlock in dev_queue_xmit(), Addet experimental support for ingress queue (just only IPV4), Addet some comments to the sources, Fixed example in README + new example for ingress, The kernel patch for 2.4.25 was broken (oops)

Using GNU/Linux is part of my job. Sometimes i need to change or include something special in to linux kernel, so the Linux kernel hacking being also a part of my job. Because i doing it also for fun, i setup this little page to show my first public project for GNU/Linux. Over the Internet exist some implementations to have common traffic controler over multiple network interfaces (IMQ), but all have some issues regarding stability and functionality. So i decide joinn together all good ideas i found, and even more :) ... Read below.

INTRODUCTION
INSTALATION - KERNEL PATCH
INSTALATION - NETFILTER USERSPACE
TODO
CHANGELOG
EXAMPLE1
EXAMPLE2
LINKS

This is the intermediate queue device for GNU/Linux. Original version of this driver was writen by Martin Devera and Patrick McHardy. This is new implementation that use devices EOS event.  Current version contain original netfilter support writen by Patrick McHardy. Here is also ability to have multiple imq devices. Supported are both ingress and egress queue.

Current version support only 2.4.25 kernel(TODO). To apply the patch copy the imq-2.4.25-1.1.diff file in to the root of your kernel source tree and run:

patch -p1 << imq-2.4.25-1.1.diff

This will install kernel driver and netfilter kernel space support. Then configure, rebuild and  install new kernel.

Current version not support patch-o-matic(TODO). Simply copy contens of the extensions folder in
to <iptables-userspace>/extensions folder (eg /usr/src/iptables-1.2.9/extensions) and rebuild the
iptables.

- netfilter "nosync" option, do not use device EOS
- netfilter "reset" option to clear imq flags
- netfilter "match module" to check imq flags
- netfilter patch-o-mantic support
- support for kernel 2.6.x (i using only 2.4.x series)
- code and documentation cleanup, english are not my "native" languages

1.0 - Initial version. Its rewrite of imq device by Martin Devera
      and Patrick McHardy. This version can queue only egress trafics
      and have support for device EOS. Netfilter implementation and driver
      skeleton is unchanged from Patric McHardy version of IMQ.
1.1 - Fixed bug with spinlock in dev_queue_xmit()
      Addet experimental support for ingress queue (just only IPV4)
      Addet some comments in to source
      Fixed example in README + new example for ingress
      The kernel patch for 2.4.25 was broken (oops)

This example show network interface independet traffic controller. Its complette example to show imq device usage for a router that have five network interfaces and ethernet bridge with ebtables patch. Trafics controler is used to manage upload and download bandwidth.

We have assigned more public IP address from ISP with 1Mbit for download and 1Mbit for upload. "Customers" will have assigned private (NATed) and public network address.

We have those NIC's assigned for:
eth0  - Internet from ISP
eth1  - "Customers" with public IP's
wlan0 - "Customers" with public IP's  (WiFi)
eth2  - "Customers" with private IP's
wlan1 - "Customers" with private IP's (WiFi)

Public IP's range will be 195.66.77.0/24 and private IP's range 10.0.0.0/16. The example not show
the firewall and wireless interfaces setup.

The example script with comment:

#!/bin/sh

# Example script to show IMQ driver usage
# Author : Jiri Fojtasek <jiri.fojtasek(at)hlohovec.net> http://hyperfighter.sk/qos
# Version: 1.0

#NIC's and bridge br0 connected to ISP
 brctl addbr br0
 brctl addif br0 eth0
 brctl addif br0 eth1
 brctl addif br0 wlan0
 ifconfig eth0 0.0.0.0 up
 ifconfig eth1 0.0.0.0 up
 ifconfig wlan0 0.0.0.0 up
 ifconfig br0 195.66.77.1 netmask 255.255.255.0
 route add default gw 195.66.77.99

#NIC's for private network
 ifconfig eth2 10.0.1.1 netmask 255.255.255.0
 ifconfig wlan1 10.0.2.1 netmask 255.255.255.0

#Setup IMQ devices (numdevs parameter specifies number of imq devices will be loaded)
 modprobe imq numdevs=2
 ifconfig imq0 up
 ifconfig imq1 up

#Setup the NAT
 iptables -t nat -A POSTROUTING -s 10.0.0.0/16 -o br0 -j SNAT --to 195.66.77.1
 
#Setup traffic controler for imq0 (download)
 tc qdisc del dev imq0 root
 tc qdisc add dev imq0 root handle 1 htb default 99
 tc class add dev imq0 parent 1: classid 1:10 htb rate 1Mbit
 
 #Customer 1 with rate 64 Kbit
  tc class add dev imq0 parent 1:10 classid 1:1000 htb rate 64Kbit ceil 64Kbit
  tc qdisc add dev imq0 parent 1:1000 handle 1000 sfq
  tc filter add dev imq0 parent 1:0 protocol ip prio 200 handle 1000 fw classid 1:1000

 #Customer 2 with rate 128 Kbit
  tc class add dev imq0 parent 1:10 classid 1:1010 htb rate 128Kbit ceil 128Kbit
  tc qdisc add dev imq0 parent 1:1010 handle 1010 sfq
  tc filter add dev imq0 parent 1:0 protocol ip prio 200 handle 1010 fw classid 1:1010

 #Customer 3 with rate 256 Kbit
  tc class add dev imq0 parent 1:10 classid 1:1020 htb rate 256Kbit ceil 256Kbit
  tc qdisc add dev imq0 parent 1:1020 handle 1020 sfq
  tc filter add dev imq0 parent 1:0 protocol ip prio 200 handle 1020 fw classid 1:1020

 #Default class with rate 32 Kbit
  tc class add dev imq0 parent 1:10 classid 1:99 htb rate 32Kbit ceil 32Kbit

#Setup traffic controler for imq1 (upload)
 tc qdisc del imq1 root
 tc qdisc add dev imq1 root handle 1 htb default 98
 tc class add dev imq1 parent 1: classid 1:20 htb rate 1Mbit
 
 #Customer 1 with rate 64 Kbit
  tc class add dev imq1 parent 1:20 classid 1:2000 htb rate 64Kbit ceil 64Kbit
  tc qdisc add dev imq1 parent 1:2000 handle 2000 sfq
  tc filter add dev imq1 parent 1:0 protocol ip prio 200 handle 2000 fw classid 1:2000

 #Customer 2 with rate 128 Kbit
  tc class add dev imq1 parent 1:20 classid 1:2010 htb rate 128Kbit ceil 128Kbit
  tc qdisc add dev imq1 parent 1:2010 handle 2010 sfq
  tc filter add dev imq1 parent 1:0 protocol ip prio 200 handle 2010 fw classid 1:2010

 #Customer 3 with rate 256 Kbit
  tc class add dev imq1 parent 1:20 classid 1:2020 htb rate 256Kbit ceil 256Kbit
  tc qdisc add dev imq1 parent 1:2020 handle 2020 sfq
  tc filter add dev imq1 parent 1:0 protocol ip prio 200 handle 2020 fw classid 1:2020

 #Default class with 32 Kbit
  tc class add dev imq1 parent 1:20 classid 1:99 htb rate 32Kbit ceil 32Kbit

#Setup nfmark for each Customer

 #Customer 1 with public IP 195.66.77.2
  #Download
   iptables -t mangle -A POSTROUTING -d 195.66.77.2 -j MARK --set-mark 1000
  #Upload
   iptables -t mangle -A POSTROUTING -s 195.66.77.2 -j MARK --set-mark 2000

 #Customer 2 with private IP 10.0.1.2
  #Download
   iptables -t mangle -A POSTROUTING -d 10.0.1.2 -j MARK --set-mark 1010
  #Upload
   iptables -t mangle -A POSTROUTING -s 10.0.1.2 -j MARK --set-mark 2010

 #Customer 3 with private IP 10.0.2.2
  #Download
   iptables -t mangle -A POSTROUTING -d 10.0.2.2 -j MARK --set-mark 1020
  #Upload
   iptables -t mangle -A POSTROUTING -s 10.0.2.2 -j MARK --set-mark 2020

#And finnaly direct traffic to right IMQ device :)
 #Download
  iptables -t mangle -A POSTROUTING -d 10.0.0.0/16    -j IMQ --todev 0
  iptables -t mangle -A POSTROUTING -d 195.66.77.0/24 -j IMQ --todev 0
 #Upload
  iptables -t mangle -A POSTROUTING -s 10.0.0.0/16    -j IMQ --todev 1
  iptables -t mangle -A POSTROUTING -s 195.66.77.0/24 -j IMQ --todev 1

Simply example to limit speed of incoming e-mails to 64Kbit:

#!/bin/sh

modprobe imq

ifconfig imq0 up

tc qdisc del dev imq0 root

tc qdisc add dev imq0 handle 1: root htb default 1
tc class add dev imq0 parent 1: classid 1:1 htb rate 64kbit
tc qdisc add dev imq0 parent 1:1 handle 2 sfq

iptables -t mangle -A PREROUTING -i eth0 -p TCP --dport 25 -j IMQ

Linux Advanced Routing & Traffic Control
Original IMQ by Martin Devera
Patrick McHardy IMQ implementation with netfilter
Roy's IMQ implementation with netfilter
Current IMQ implementation

Copyright (C)2004 Jiri Fojtasek