slow

#!/bin/bash
#
# slow
#
# Simulates a low bandwidth, high-latency network connection
#
# Requires a Linux operating system with the 'tc' traffic control tool
#
# Author: Richard Bullington-McGuire <richard@moduscreate.com>
# Author: Mike Schwartz <mike@moduscreate.com>
#
# Copyright 2012 Modus Create, Inc.
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject
# to the following conditions:
#
# The above copyright notice and this permission notice shall be included
# in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
# OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
# IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
# CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
# TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
# Version Change
# 0.1 first version
# 0.2 @aloysius implements packet loss
# 0.3 @sunapi386 implements the active device selected by default
# 0.4 @sunapi386 implements packet duplication, corruption, reordering
# 0.5 @sunapi386 implements reset after timeout; to recover device without a reboot
VERSION=0.5

current_used_device() {
  gateway=$(traceroute -m 1 google.com | tail -n 1 | cut -d' ' -f4)
  device=$(/sbin/route | grep $gateway | awk '{ print $NF }')
  echo $device
}

device=$(current_used_device)
bandwidth=100kbps
latency=350ms
packetloss=0%
duplication=0%
corruption=0%
reordering=0%
self_reset_delay_s=0
command=slow
retcode=0
PATH=/sbin:/bin:/usr/sbin:/usr/bin

echorun() {
  echo -E '#' "$@"
  "$@"
}

if ! which tc > /dev/null; then
  echo "Aborting: No 'tc' iptables firewall traffic conditioner found" 1>&2
  echo "This requires the Linux iptables firewall." 1>&2
  exit 1
fi

if [ $EUID -ne 0 ]; then
  echo "Aborting: you must run this as root."
  exit 2
fi


# Option processing courtesy of Stack Overflow question
# http://stackoverflow.com/questions/402377/using-getopts-in-bash-shell-script-to-get-long-and-short-command-line-options/7680682#7680682
# Questioner: gagneet http://stackoverflow.com/users/35416/gagneet
# Answer: http://stackoverflow.com/a/9899366
# Answerer:  http://stackoverflow.com/users/375889/jakesandlund


while test $# -gt 0
do
  case $1 in

  # Normal option processing
    -h | --help)
      # usage and help
      command=help
      break
      ;;
    -v | --version)
      command=version
      break
      ;;
    -d | --device)
      shift
      device=$1
      ;;
    -b | --bandwidth)
      shift
      bandwidth=$1
      ;;
    -l | --latency)
      shift
      latency=$1
      ;;
    -p | --packetloss)
      shift
      packetloss=$1
      ;;
    -u | --duplication)
      shift
      duplication=$1
      ;;
    -c | --corruption)
      shift
      corruption=$1
      ;;
    -r | --reordering)
      shift
      reordering=$1
      ;;
    -s | --self_reset_delay_s)
      shift
      self_reset_delay_s=$1
      ;;
  # ...

  # Special cases
    --)
      break
      ;;
    --*)
      # error unknown (long) option $1
      ;;
    -?)
      # error unknown (short) option $1
      ;;
   #
   # Shortcuts
       AMPS|amps)
         command=slow
         bandwidth=14kbps
         latency=250ms
         ;;
       EDGE|edge|2.5G|GPRS|gprs)
         command=slow
         bandwidth=50kbps
         latency=200ms
         ;;
       3G|3g)
         command=slow
         bandwidth=1000kbps
         latency=200ms
         ;;
       4G|4g)
         command=slow
         bandwidth=10000kbps
         latency=100ms
         ;;
       modem-0.1k|modem-110)
         command=slow
         bandwidth=110bps
         latency=350ms
         ;;
       modem-0.3k|modem-300)
         command=slow
         bandwidth=300bps
         latency=300ms
         ;;
       modem-1.2k|modem-1200)
         command=slow
         bandwidth=1200bps
         latency=280ms
         ;;
       modem-2.4k|modem-2400)
         command=slow
         bandwidth=2400bps
         latency=250ms
         ;;
       modem-9.6k|modem-9600)
         command=slow
         bandwidth=9600bps
         latency=200ms
         ;;
       modem-14.4k|modem-14400)
         command=slow
         bandwidth=14400bps
         latency=150ms
         ;;
       modem-28.8k|modem-28800)
         command=slow
         bandwidth=28800bps
         latency=150ms
         ;;
       modem-56k|modem-56000)
         command=slow
         bandwidth=56kbps
         latency=120ms
         ;;
       56k)
         command=slow
         bandwidth=56kbps
         latency=40ms
         ;;
       T1|t1)
         command=slow
         bandwidth=1500kbps
         latency=20ms
         ;;
       T3|t3)
         command=slow
         bandwidth=45mbps
         latency=10ms
         ;;
       DSL|dsl)
         command=slow
         bandwidth=2mbps
         latency=40ms
         ;;
       cablemodem)
         command=slow
         bandwidth=10mbps
         latency=20ms
         ;;
       wifi-a|wifi-g)
         command=slow
         bandwidth=54mbps
         latency=5ms
         ;;
       wifi-b)
         command=slow
         bandwidth=11mbps
         latency=10ms
         ;;
       wifi-n)
         command=slow
         bandwidth=110mbps
         latency=2ms
         ;;
       vsat)
         command=slow
         bandwidth=5mbps
         latency=500ms
         ;;
       clear|reset)
         command=clear
         ;;
       status)
         command=status
         break
         ;;


  # FUN STUFF HERE:
  # Split apart combined short options
    -*)
      split=$1
      shift
      set -- $(echo "$split" | cut -c 2- | sed 's/./-& /g') "$@"
      continue
      ;;

  # Done with options
    *)
      break
      ;;
  esac

  # for testing purposes:
  echo "param $1"

  shift
done

echo "command=$command"
echo "-d device=$device"
echo "-b bandwidth=$bandwidth"
echo "-l latency=$latency"
echo "-p packetloss=$packetloss"
echo "-u duplication=$duplication"
echo "-c corruption=$corruption"
echo "-r reordering=$reordering"
echo "-s self_reset_delay_s=$self_reset_delay_s"

case $command in
  help)
    echo $0
    echo 'Usage: slow <network-type> [-d device] [-b bandwidth] [-l latency] [-p %drop] [-u %duplication] [-c %corruption] [-r %reordering] [-s self_reset_delay_s]'
    echo '       slow reset'
    echo '       slow status'
    echo
    echo '"network-type" type can be:'
    echo '  GPRS'
    echo '  GSM'
    echo '  EDGE'
    echo '  2.5G'
    echo '  GPRS'
    echo '  3G'
    echo '  4G'
    echo '  modem-2.4k'
    echo '  modem-9.6k'
    echo '  modem-14.4k'
    echo '  modem-28.8k'
    echo '  modem-56k'
    echo '  56k'
    echo '  T1'
    echo '  T3'
    echo '  DSL'
    echo '  cablemodem'
    echo '  wifi-a'
    echo '  wifi-b'
    echo '  wifi-g'
    echo '  wifi-n'
    echo '  eth-10'
    echo '  eth-100'
    echo '  eth-1000'
    echo '  vsat'
    echo '  vsat-busy'
    ;;
  version)
    # version info
    echo "slow version $VERSION"
    echo "Copyright (c) 2012 Modus Create"
    ;;
  slow)
    # Credit to Superuser for the basic commands that run this
    # Question: http://superuser.com/questions/147156/simulating-a-low-bandwidth-high-latency-network-connection-on-linux
    # Author: Justin L. http://superuser.com/users/38740/justin-l
    # Answer: http://superuser.com/a/147434/159810
    if  tc qdisc show dev $device | fgrep -q "qdisc htb 1: root"; then
      verb=change
      echo "Changing existing queuing discipline"
    else
      verb=add
      echo "Adding new queuing discipline"
      echorun tc qdisc $verb dev $device root handle 1: htb default 12
    fi
    if ! lsmod | fgrep -q "sch_netem"; then
      modprobe sch_netem
    fi
    echorun tc class $verb dev $device parent 1:1 classid 1:12 htb rate $bandwidth ceil $bandwidth  &&
    echorun tc qdisc $verb dev $device parent 1:12 netem delay $latency loss $packetloss duplicate $duplication corrupt $corruption reorder $reordering
    if [ ${self_reset_delay_s} -ne 0 ]; then
        echo "Resetting after ${self_reset_delay_s}s of slow"
        sleep ${self_reset_delay_s}
        echo resetting queueing discipline
        echorun tc qdisc del dev ${device} root
    fi
    retcode=$?
    ;;
  clear)
    echo resetting queueing discipline
    echorun tc qdisc del dev $device root
    retcode=$?
    ;;
  status)
    echorun tc qdisc
    retcode=$?
    ;;
esac

exit $retcode