access_point_if_no_wifi

#!/bin/bash
#
# Interface checker
# Checks to see whether interface has an IP address, if it doesn't assume it's down and start hostapd
# Author : SirLagz
#
Interface='wlan0'
HostAPDIP='192.168.42.1'
echo "-----------------------------------"
echo "Checking connectivity of $Interface"
NetworkUp=`/sbin/ifconfig $Interface`
IP=`echo "$NetworkUp" | grep inet | wc -l`
if [[ $IP -eq 0 ]]; then
  echo "Connection is down"
  hostapd=`pidof hostapd`
  if [[ -z $hostapd ]]; then
    # If there are any more actions required when the interface goes down, add them here
    echo "Attempting to start hostapd"
    /etc/init.d/hostapd start
    echo "Attempting to start dnsmasq"
    /etc/init.d/dnsmasq start
    echo "Setting IP Address for wlan0"
    /sbin/ifconfig wlan0 $HostAPDIP netmask 255.255.255.0 up
  fi
elif [[ $IP -eq 1 && $NetworkUp =~ $HostAPDIP ]]; then
  echo "IP is $HostAPDIP - hostapd is running"
  else
  echo "Connection is up"
  hostapd=`pidof hostapd`
  if [[ ! -z $hostapd ]]; then
    echo "Attempting to stop hostapd"
    /etc/init.d/hostapd stop
    echo "Attempting to stop dnsmasq"
    /etc/init.d/udhcpd stop
    echo "Renewing IP Address for $Interface"
    /sbin/dhclient wlan0
  fi
fi
echo "-----------------------------------"