wifi-connect

wifi-connect.sh

#!/usr/bin/env bash
ProgName=$(basename $0)

function main(){
	# Main Caller Function
	parse_args "$@"

}
function parse_args(){
	sub_command=$1;
	case $sub_command in 
		"" | "-h" | "--help")
			print_manual
			;;
		"-d" | "--debug" )
			declare DEBUG=true
			sub_command=$2
			shift
			;& 
		"connect" | "disconnect" | "status" | "scan" )
			shift;
			EXEC_ID=$(id -u)
			if [[ $EXEC_ID != 0 ]];then
				>&2 echo "Execute with sudo or run as root"
				exit 1
			fi
			sub_${sub_command} "$@"
			;;
		"ip" )
			shift;
			sub_${sub_command} "$@"
			;;
		*)
			>&2 echo "Command Not Found"
			>&2 print_manual
			;;


		esac
	}
###############
# SubCommands #
###############
function sub_disconnect(){
	killall wpa_supplicant
	return $?
}
function sub_status() {
	if [[ -z $device_to_use ]];then
		find_wireless_iface
	fi
	device_unconnected $device_to_use
	if [[ $? == 0 ]];then
		>&2 echo "No access to internet"
		exit 1
	else
		>&2 echo "Connected to internet"
		exit 0 
	fi

}
function sub_scan(){
	if [[ -z $device_to_use ]];then
		find_wireless_iface
	fi
	OLD_IFS=$IFS
	IFS=$'\n'
	SSIDS=($(scan_devices $device_to_use))
	if [[ -z $SSIDS ]]; then
		>&2 echo "No Wifi Device Found"
		exit 1
	fi
	IFS=$OLD_IFS
	for i in "${!SSIDS[@]}";do
		printf "%s. %s\n" "$(( $i + 1 ))" "${SSIDS[$i]}"
	done
	return 0
}
function sub_ip(){
	PARSED_ARGUMENTS=$(getopt -n ip -o ie -l internal,external -- "$@") 
	VALID_ARGUMENTS=$?
	if [[ "$VALID_ARGUMENTS" != "0" ]];then
		print_manual
		exit 1
	fi
	eval set -- "$PARSED_ARGUMENTS"
	while :
	do 
		case "$1" in
			-i | --internal ) 
				declare INTERNAL=true
				shift;
				;;
			-n | --external )
				declare EXTERNAL=true
				shift;
				;;
			-- ) 
				shift;
				break
				;;
		esac

	done
	if [[ -z $device_to_use ]];then
		find_wireless_iface
	fi
	is_iface_up $device_to_use;
	if [[ $? != 0 ]];then
		>&2 echo "Wireless device $device_to_use is down"
		exit $?
	fi
	device_unconnected $device_to_use;
	if [[ $? == 0 ]];then
		>&2 echo "Either you are not connected to router or not reachable to internet"
		exit 1
	fi
	
	INTERNAL_IP=$(ip a show $device_to_use 2>/dev/null | grep -w inet | awk '{print $2}' | cut -f1 -d'/')
	EXTERNAL_IP=$(dig +short myip.opendns.com @resolver1.opendns.com 2>/dev/null)
	if [[ -z $INTERNAL && -z $EXTERNAL ]];then
		INTERNAL=true
		EXTERNAL=true
	fi
	if [[ $INTERNAL == true ]];then
		echo "INTERNAL IP: $INTERNAL_IP"
	fi
	if [[ $EXTERNAL == true ]];then
		echo "EXTERNAL IP: $EXTERNAL_IP"
	fi

}
function sub_connect() {
	PARSED_ARGUMENTS=$(getopt -n connect -o isp -l interactive,ssid,pass -- "$@") 
	VALID_ARGUMENTS=$?
	if [[ "$VALID_ARGUMENTS" != "0" ]];then
		print_manual
		exit 1
	fi
	eval set -- "$PARSED_ARGUMENTS"
	while :
	do 
		case "$1" in
			-i | --interactive ) 
				declare INTERACTIVE=true
				shift;
				;;
			-s | --ssid )
				declare SSID="$1"
				shift;
				;;
			-p | --pass )
				declare PASS="$1"
				shift;
				;;
			-- ) 
				shift;
				break
				;;
		esac

	done
	if [[ -n $DEBUG ]];then
		echo "Finding wireless iface"
	fi
	find_wireless_iface
	if [[ $INTERACTIVE == "true" ]];then
		sub_scan
		printf "Which device you want to connect to? (Enter Serial No): "
		read ssid_index
		ssid_to_connect="${SSIDS[$((ssid_index - 1))]}"
		printf "Enter Password: "
		read -s password
	else
		if [[ -z $SSID || -z $PASS ]];then
			>&2 echo "--ssid and --pass are required if --interactive is not provided"
			print_manual
			exit 1
		fi
		ssid_to_connect="$SSID"
		password="$PASS"
	fi
	printf "\nConnecting ${ssid_to_connect}\n"
	connect_to_wifi "$ssid_to_connect" "$password" "$device_to_use"

}

####################
# HELPER FUNCTIONS #
####################
function connect_to_wifi(){
	if [[ -n $DEBUG ]];then
		cat << EOF
SSID:        $1
PASSWORD:    $2
IFACE:       $3
EOF
	fi
	base_path=/etc/wpa_supplicant/devices
	if [[ ! -d $base_path ]];then
		mkdir -p $base_path
	fi
	file_name=$( echo -n "$1" | sed 's#\s#_#g')
	wpa_existing_processes="$(ps -ax | grep wpa_supplicant | wc -l)"
	if [[ $wpa_existing_processes -gt 1 ]];then
		sub_disconnect
	fi	
	wpa_passphrase "${1}" "$2" > ${base_path}/${file_name}.yaml
	wpa_supplicant -B -D wext -i $3 -c ${base_path}/${file_name}.yaml &> /dev/null
	if [[ $? == 0 ]];then
		dhclient -r && sleep 5 && dhclient &> /dev/null
		if [[ $? == 0 ]]; then
			ping -c 1 8.8.8.8 &> /dev/null
			if [[ $? == 0 ]];then
				echo Connected to internet
				return 0
			else
				echo Unable to reach internet, check your router
				exit 1
			fi
		fi
	else
		>&2 echo "Unable to connect to wifi. Developer could help you troubleshoot"
		exit 1
	fi

}

function is_iface_up(){
	ip link show up | grep $1 &> /dev/null
	return $?
}

function scan_devices(){
	is_iface_up $1;
	l_status=$?
	if [[ $l_status != 0 ]]; then
		ip link set $1 up
		if [[ $? != 0 ]];then
			>&2 echo "Failed to start device"
			exit 1
		fi
	fi
	iw dev $1 scan 2>/dev/null | grep SSID | sed 's#\sSSID: ##g' | sort -u
	return $?
}
function device_unconnected(){
	# To Check whether wireless device not connected
	if [[ -z $1 ]];then
		>&2 echo "Device Not Provided" 
		exit 1
	fi
	device_status=$(iw dev $1 link 2> /dev/null)
	if [[ "${device_status^^}" == "NOT CONNECTED." ]];then
		return 0
	fi
	return 1
}

function find_wireless_iface(){
	devices=($(ls /sys/class/net | grep wl))
	if [[ -z $devices ]];then
		>&2 echo "No Wireless interface detected"
		exit 1
	fi
	device_to_use="${devices[0]}"
	return 0
}

###########
# Manuals #
###########
function print_manual(){
	cat << EOF
USAGE: $ProgName [GLOBAL_ARGS] SUB_COMMAND [COMMAND_ARGS]

GLOBAL_ARGS:
--debug         -d                 To Print Debug statement
--help          -h                 Print this manual

SUB_COMMANDS:
connect                            To connect wifi to router
disconnect                         To disconnect with existing router
ip                                 To know your ip address
scan                               To scan nearby router.
status                             To know current status of the wireless router

COMMAND_ARGS:

1. connect Args

--interactive   -i                 To scan and connect interactively           
--ssid          -s                 To provide ssid name [required if --interactive is not provided]
--pass          -p                 To provide

2. ip

--internal      -i                 To print internal ip
--external      -e                 To print external ip

EOF

}
###################################### Execution start from Here ###################################
main "$@"