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plq/README.md

Forked from denilsonsa/README.md
Created Jul 30, 2018
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slow

This bash script offers quick shortcuts to simulate slower network connections. It is useful when you need to simulate a wireless network on a Linux network server, especially when you are using a virtual machine guest on your local machine or in the cloud.

slow 3G                   # Slow network on default eth0 down to 3G wireless speeds
slow 3G -l 600ms -p 10%   # slow network on eth0 and setup latency to 600ms packetloss to 10%
slow reset                # Reset connection for default eth0 to normal
slow vsat --latency=500ms # Simulate satellite internet  with a high latency
slow dsl -b 1mbps         # Simulate DSL with a slower speed than the default
slow modem-56k -d eth0    # Simulate a 56k modem on the eth1 device. eth0 is unchanged.

Credits

Richard Bullington-McGuire richard@moduscreate.com wrote the script inspired by a UI suggestion from Mike Schwartz mike@moduscreate.com.

Stack Overflow and Superuser questions that helped:

An Aptivate blog post lent some inspiration, as did this script for throttling bandwidth.

*fork version add implementation packet loss

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.
#!/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.
#
#
# Changelog
# ---------
#
# 0.1: first version
# 0.2: implementation packet loss by aloysius
# 0.3: add ability to use own veth device for offline testing
#
# Current url: https://gist.github.com/plq/53b4099df8e4a531593991dadc06c223
#
DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )" #"
VERSION=0.3
netns=slow
device=slow1
bandwidth=100kbit
latency=1350ms
packetloss=0%
command=slow
retcode=0
PATH=/sbin:/bin:/usr/sbin:/usr/bin
echorun() {
echo -E '#' "$@"
"$@"
}
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
;;
-n | --netns)
shift
netnse=$1
;;
-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|amps)
command=slow
bandwidth=14kbit
latency=250ms
;;
EDGE|edge|2.5G|GPRS|gprs)
command=slow
bandwidth=50kbit
latency=200ms
;;
3G|3g)
command=slow
bandwidth=1000kbit
latency=200ms
;;
4G|4g)
command=slow
bandwidth=10000kbit
latency=100ms
;;
modem-0.1k|modem-110)
command=slow
bandwidth=110bit
latency=350ms
;;
modem-0.3k|modem-300)
command=slow
bandwidth=300bit
latency=300ms
;;
modem-1.2k|modem-1200)
command=slow
bandwidth=1200bit
latency=280ms
;;
modem-2.4k|modem-2400)
command=slow
bandwidth=2400bit
latency=250ms
;;
modem-9.6k|modem-9600)
command=slow
bandwidth=9600bit
latency=200ms
;;
modem-14.4k|modem-14400)
command=slow
bandwidth=14400bit
latency=150ms
;;
modem-28.8k|modem-28800)
command=slow
bandwidth=28800bit
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
;;
clear-dev)
command="clear clear-dev"
;;
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 $1"
shift
done
echo "netns=$netns"
echo "device=$device"
echo "command=$command"
echo "bandwidth=$bandwidth"
echo "latency=$latency"
echo $command
for c in $command; do
case $c 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 $VERSION"
echo "Copyright (c) 2012 Modus Create"
;;
slow)
# enable forwarding
echo "echo 1 > /proc/sys/net/ipv4/ip_forward"
echo 1 > /proc/sys/net/ipv4/ip_forward
# generate sudoers file if sudo is detected
if [ -n "$SUDO_USER" ]; then
echo sudo detected, generating sudoers.d file
sudoers_line="$SUDO_USER ALL = (ALL) NOPASSWD: $(which ip) netns exec $netns sudo -u $SUDO_USER *"
echo "$sudoers_line" | tee /etc/sudoers.d/99-netns-$netns
fi
# add device if it does not exist
if ip link | egrep -q "^[0-9]+: $device@[^:]+:" ; then
echo using existing network interface $device
else
echo adding new netns $netns
echorun ip netns add $netns
echo adding new veth device ${netns}0
echorun ip link add ${netns}0 type veth peer name ${netns}1
echorun ip link set ${netns}0 netns $netns
# non-routed block allocated to uk dwp
# https://news.ycombinator.com/item?id=9587746
echorun ip netns exec $netns ip addr add dev ${netns}0 51.0.0.1/16
echorun ip addr add dev ${netns}1 51.0.1.1/16
fi
echorun ip netns exec $netns ip link set up dev ${netns}0
echorun ip link set up dev ${netns}1
echorun ip netns exec $netns route add default gw 51.0.1.1 #dev ${netns}0
# 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 $packetloss
retcode=$?
;;
clear)
echo resetting queueing discipline
echorun tc qdisc del dev $device root
retcode=$?
;;
clear-dev)
if ! ip tuntap | egrep -q "^${device}:" ; then
echo $device not a tun/tap device, not deleted.
retcode=1;
else
echo deleting $device
echorun ip tuntap del dev ${device}0 mode tap
echorun ip tuntap del dev ${device}1 mode tap
retcode=$?
fi
;;
status)
echorun tc qdisc
retcode=$?
;;
esac
if [ $retcode != '0' ]; then
echorun exit $retcode
fi
done
echo
echo 1. make sure you bind your server to: 51.0.1.1
echo 2. make sure you run slowed process with: "sudo ip netns exec $netns sudo -u $USER \"<whatever>\""
echo
echo Have fun'!'
echo
exit $retcode
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