pingloop.sh

#!/bin/bash

# PINGLOOP with OS X wifi bugfix

# Will ping google.com or domain provided via parameter.
# Keep this running in background to monitor connection and fix automatically.

# By Carlos Navarro, with thanks to Kevin Ritchie for the wifi bugfix code.
# Bugfix code provided here: http://osxdaily.com/2015/10/16/fix-wi-fi-problems-mac-os-x-el-capitan/

# NOTE: This is not a proper fix. This simply refreshes wifi configuration when connection failure is
#       detected, equivalent to turning wifi off/on but faster. There could be, at worst, up to a
#       second of no connectivity, which may break some active connections.
#       Permanent fix remains up to Apple.

# Contact via:
#  * Twitter: twitter.com/Nosgoroth
#  * Email: nosgoroth@gmail.com

# Pingloop output legend
#  * Green "O"  -> Ping was OK
#  * Red "X"	-> Ping failed
#  * Yellow "!" -> Wifi bugfix was applied

#################
# Configuration #
#################

# Set to zero to apply fix immediately after offline condition detected.
# A nonzero value prevents notifications for momentary ping errors.
min_seconds_before_offline=0

# Set to false to disable toast notifications.
notify=true

# Set to false to disable OS X wifi bug fix.
wifi_bugfix=true

# Set to true to enable some extra output.
debug=false

# Change default address to ping here.
# You can also specify a domain via parameters (pingloop apple.com)
defaultaddr=google.com



#############
# Functions #
#############

not(){
	osascript -e "display notification \"${*/\"/\\\"}\" with title \"Alert\""
}

do_ping(){
	res=$(ping -q -c 1 -t 1 $address &> /dev/null)
	return $?
}

apply_wifi_bugfix(){
	echo "add State:/Network/Interface/en0/RefreshConfiguration temporary" | scutil
}



########
# Init #
########

tput clear

if [[ -z "$1" ]]; then
	address=$defaultaddr
	addrname=Network
else
	address=$1
	addrname=Domain\ $1
fi

_user=$(whoami)
if [ "$_user" == "root" ]; then
	_root=true
else
	_root=false
fi



##############
# Info block #
##############

if $debug; then
	echo "$(tput bold)$(tput setaf 3)DEBUG MODE$(tput sgr 0)"
	echo
fi


if $wifi_bugfix; then
	if $_root; then
		echo "WiFi bufgix: $(tput setaf 2)enabled$(tput sgr 0)"
	else
		echo "WiFi bufgix: $(tput bold)$(tput setaf 3)enabled but cannot apply$(tput sgr 0) - run with $(tput bold)sudo$(tput sgr 0)"
	fi
else
	echo "WiFi bufgix: $(tput setaf 1)disabled$(tput sgr 0)"
fi

if $notify; then
	echo "Toast notifications: $(tput setaf 2)enabled$(tput sgr 0)"
else
	echo "Toast notifications: $(tput setaf 1)disabled$(tput sgr 0)"
fi

if (( $min_seconds_before_offline > 0 )); then
	echo "Offline condition will be treated after it persists for $(tput bold)$(tput setaf 2)$min_seconds_before_offline$(tput sgr 0) seconds"
else
	echo "Offline condition will be treated $(tput bold)$(tput setaf 3)immediately$(tput sgr 0)"
fi
echo

echo "Pinging $(tput bold)$address$(tput sgr 0) in loop. Press $(tput bold)Ctrl+C$(tput sgr 0) to exit."



#############
# Main loop #
#############

trap 'echo; echo Exiting...; exit' INT

s="0"
ctrbuf=-1
minbuf=$min_seconds_before_offline

while true; do
	do_ping &> /dev/null

	r=$?

	if [ "$r" == "0" ]; then
		echo -n "$(tput setaf 2)O$(tput sgr 0)"
	else
		echo -n "$(tput setaf 1)X$(tput sgr 0)"
	fi

	if [ "$s" != "$r" ] && (( $ctrbuf > $minbuf )); then
		ctrbuf=0
	else
		ctrbuf=$(( ctrbuf + 1 )) 
	fi

	$debug && echo -n ".$r$s."
	
	if [ "$r" == "0" ] && [ "$s" != "0" ]; then
		$debug && echo -n "~"
		$notify && not "$addrname online"
		s="$r"
	elif [ "$r" != "0" ] && [ "$s" == "0" ] && (( $ctrbuf + 1 > $minbuf )); then
		$debug && echo -n "~"
		if $wifi_bugfix && $_root; then
			apply_wifi_bugfix
			echo -n "$(tput bold)$(tput setaf 3)!$(tput sgr 0)"
			$notify && not "Applied wifi bugfix"
		else
			$notify && not "$addrname offline"
		fi
		s="$r"
	fi

	if [ "$r" == "0" ]; then
		sleep 1
	fi
done