Raspberry PI - Switch between Hotspot and Wifi modes

README.md

Inspiration from http://www.raspberryconnect.com/network/item/330-raspberry-pi-auto-wifi-hotspot-switch-internet

Pre-requisites:

• A working Wifi (configured in /etc/wpa_supplicant/wpa_supplicant.conf)
• A working hotspot setup (configured in /etc/hostapd/hostapd.conf)
• The /etc/dhcpcd.conf file has following contents:

interface wlan0
  nohook wpa_supplicant

Installation:

• Copy the file autohotspot to /usr/bin/autohotspot and chmod a+x

• Copy the file autohotspot.service to /etc/systemd/system/

• systemctl enable autohotspot

• Create a file /boot/wificfg.txt with a single line. The contents supported are:

  • hotspot
    • Automatically start Raspberry PI in hotspot mode
  • wifi
    • Automatically start Raspberry PI in wifi mode
  • wifiOrhotspot
    • While booting, Try Wifi client for 10s, if not connected, Start hotspot mode

• If the file /boot/wificfg.txt is not present, then start in hotspot mode

autohotspot.service

[Unit]
Description=Automatically generates an internet Hotspot when a valid ssid is not in range
After=multi-user.target

[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/usr/bin/autohotspot service

[Install]
WantedBy=multi-user.target

autohotspot.sh

#!/bin/bash

echo "$1"

function show_status() {
  sleep 2
  ifconfig wlan0
  iwconfig
  ps auxww | grep wpa_supplicant
  systemctl status dnsmasq
  systemctl status hostapd
}

function hotspot_off() {
  echo "Stopping hotspot and starting normal"
  ip link set dev wlan0 down
  systemctl stop dnsmasq
  systemctl stop hostapd
  ip addr flush wlan0
  ip link set dev wlan0 up
  wpa_supplicant -B -i wlan0 -c /etc/wpa_supplicant/wpa_supplicant.conf
  dhcpcd -n wlan0
}

function hotspot_on() {
  echo "Creating hotspot"
  wpa_cli terminate
  ip addr flush wlan0
  ip link set dev wlan0 down
  rm -rf /var/run/wpa_supplicant

  ip addr add 192.168.90.1/24 brd + dev wlan0
  ip link set dev wlan0 up

  dhcpcd -k wlan0
  systemctl start dnsmasq
  systemctl start hostapd
  dhcpcd -n wlan0
}

if [[ $1 == "off" ]]; then
  hotspot_off
elif [[ $1 == "status" ]]; then
  show_status

elif [[ $1 == "on" ]]; then
  hotspot_on

elif [[ $1 == "service" ]]; then

  if [[ ! -f /boot/wificfg.txt ]]; then
     hotspot_on
     exit
  fi

  if grep -E '^hotspot' /boot/wificfg.txt
  then
     hotspot_on
     exit
  fi

  if grep -E '^wifiOrhotspot' /boot/wificfg.txt
  then
     hotspot_off
     sleep 20
     if ! wpa_cli -i wlan0 status | grep 'ip_address' >/dev/null 2>&1
     then
       hotspot_on
     fi
     exit
  fi

  if grep -E '^wifi' /boot/wificfg.txt
  then
     hotspot_off
     exit
  fi
fi