#!/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=0.1
device=eth0
bandwidth=100kbps
latency=350ms
packetloss=
command=slow
retcode=0
PATH=/sbin:/bin:/usr/sbin:/usr/bin

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
      ;;
  # ...

  # Special cases
    --)
      break
      ;;
    --*)
      # error unknown (long) option $1
      ;;
    -?)
      # error unknown (short) option $1
      ;;
   # 
   # Shortcuts
       AMPS)
         command=slow
         bandwidth=14kbit
         latency=250ms
         ;;
       EDGE|2.5G|GPRS)
         command=slow
         bandwidth=50kbit
         latency=200ms
         ;;
       3G)
         command=slow
         bandwidth=1000kbit
         latency=200ms
         ;;
       4G)
         command=slow
         bandwidth=10000kbit
         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=56kbit
         latency=120ms
         ;;
       56k)
         command=slow
         bandwidth=56kbit
         latency=40ms
         ;;
       T1|t1)
         command=slow
         bandwidth=1500kbit
         latency=20ms
         ;;
       T3|t3)
         command=slow
         bandwidth=45mbit
         latency=10ms
         ;;
       DSL|dsl)
         command=slow
         bandwidth=2mbit
         latency=40ms
         ;;
       cablemodem)
         command=slow
         bandwidth=10mbit
         latency=20ms
         ;;
       wifi-a|wifi-g)
         command=slow
         bandwidth=54mbit
         latency=5ms
         ;;
       wifi-b)
         command=slow
         bandwidth=11mbit
         latency=10ms
         ;; 
       wifi-n)
         command=slow
         bandwidth=110mbit
         latency=2ms
         ;;
       vsat)
         command=slow
         bandwidth=5mbit
         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=$command"
echo "bandwidth=$bandwidth"
echo "latency=$latency"

case $command in
  help)
    echo $0
    echo 'Usage: slow <network-type> [-d device] [-b bandwidth] [-l latency] [-p drop]'
    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 | grep "qdisc htb 1: root" >/dev/null; then
      verb=change
      echo "Changing existing queuing discipline"
    else
      verb=add
      echo "Adding new queuing discipline"
      tc qdisc $verb dev $device root handle 1: htb default 12
    fi
    tc class $verb dev $device parent 1:1 classid 1:12 htb rate $bandwidth ceil $bandwidth  &&
    tc qdisc $verb dev $device parent 1:12 netem delay $latency
    retcode=$?
    ;;
  clear)
    echo resetting queueing discipline
    tc qdisc del dev $device root
    retcode=$?
    ;;
  status)
    tc qdisc
    retcode=$?
    ;;
esac

exit $retcode