Autohotspot function

scripts/helperscripts/autohotspot

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+#!/bin/bash
+#version 0.95-41-N/HS
+
+#You may share this script on the condition a reference to RaspberryConnect.com 
+#must be included in copies or derivatives of this script. 
+
+#A script to switch between a wifi network and a non internet routed Hotspot
+#Works at startup or with a seperate timer or manually without a reboot
+#Other setup required find out more at
+#http://www.raspberryconnect.com
+
+wifidev="wlan0" #device name to use. Default is wlan0.
+#use the command: iw dev ,to see wifi interface name 
+
+IFSdef=$IFS
+cnt=0
+#These four lines capture the wifi networks the RPi is setup to use
+wpassid=$(awk '/ssid="/{ print $0 }' /etc/wpa_supplicant/wpa_supplicant.conf | awk -F'ssid=' '{ print $2 }' ORS=',' | sed 's/\"/''/g' | sed 's/,$//')
+wpassid=$(echo "${wpassid//[$'\r\n']}")
+IFS=","
+ssids=($wpassid)
+IFS=$IFSdef #reset back to defaults
+
+
+#Note:If you only want to check for certain SSIDs
+#Remove the # in in front of ssids=('mySSID1'.... below and put a # infront of all four lines above
+# separated by a space, eg ('mySSID1' 'mySSID2')
+#ssids=('mySSID1' 'mySSID2' 'mySSID3')
+
+#Enter the Routers Mac Addresses for hidden SSIDs, seperated by spaces ie 
+#( '11:22:33:44:55:66' 'aa:bb:cc:dd:ee:ff' ) 
+mac=()
+
+ssidsmac=("${ssids[@]}" "${mac[@]}") #combines ssid and MAC for checking
+
+createAdHocNetwork()
+{
+    echo "Creating Hotspot"
+    ip link set dev "$wifidev" down
+    ip a add 10.0.0.5/24 brd + dev "$wifidev"
+    ip link set dev "$wifidev" up
+    dhcpcd -k "$wifidev" >/dev/null 2>&1
+    systemctl start dnsmasq
+    systemctl start hostapd
+}
+
+KillHotspot()
+{
+    echo "Shutting Down Hotspot"
+    ip link set dev "$wifidev" down
+    systemctl stop hostapd
+    systemctl stop dnsmasq
+    ip addr flush dev "$wifidev"
+    ip link set dev "$wifidev" up
+    dhcpcd  -n "$wifidev" >/dev/null 2>&1
+}
+
+ChkWifiUp()
+{
+	echo "Checking WiFi connection ok"
+        sleep 20 #give time for connection to be completed to router
+	if ! wpa_cli -i "$wifidev" status | grep 'ip_address' >/dev/null 2>&1
+        then #Failed to connect to wifi (check your wifi settings, password etc)
+	       echo 'Wifi failed to connect, falling back to Hotspot.'
+               wpa_cli terminate "$wifidev" >/dev/null 2>&1
+	       createAdHocNetwork
+	fi
+}
+
+
+FindSSID()
+{
+#Check to see what SSID's and MAC addresses are in range
+ssidChk=('NoSSid')
+i=0; j=0
+until [ $i -eq 1 ] #wait for wifi if busy, usb wifi is slower.
+do
+        ssidreply=$((iw dev "$wifidev" scan ap-force | egrep "^BSS|SSID:") 2>&1) >/dev/null 2>&1 
+        echo "SSid's in range: " $ssidreply
+        echo "Device Available Check try " $j
+        if (($j >= 10)); then #if busy 10 times goto hotspot
+                 echo "Device busy or unavailable 10 times, going to Hotspot"
+                 ssidreply=""
+                 i=1
+	elif echo "$ssidreply" | grep "No such device (-19)" >/dev/null 2>&1; then
+                echo "No Device Reported, try " $j
+		NoDevice
+    elif echo "$ssidreply" | grep "Network is down (-100)" >/dev/null 2>&1 ; then
+        echo "Network Not available, trying again" $j
+        j=$((j + 1))
+        sleep 2
+	elif echo "$ssidreply" | grep "Read-only file system (-30)" >/dev/null 2>&1 ; then
+		echo "Temporary Read only file system, trying again"
+		j=$((j + 1))
+		sleep 2
+	elif echo "$ssidreply" | grep "Invalid exchange (-52)" >/dev/null 2>&1 ; then
+		echo "Temporary unavailable, trying again"
+		j=$((j + 1))
+		sleep 2
+	elif ! echo "$ssidreply" | grep "resource busy (-16)"  >/dev/null 2>&1 ; then
+        echo "Device Available, checking SSid Results"
+		i=1
+	else #see if device not busy in 2 seconds
+                echo "Device unavailable checking again, try " $j
+		j=$((j + 1))
+		sleep 2
+	fi
+done
+
+for ssid in "${ssidsmac[@]}"
+do
+     if (echo "$ssidreply" | grep "$ssid") >/dev/null 2>&1
+     then
+	      #Valid SSid found, passing to script
+              echo "Valid SSID Detected, assesing Wifi status"
+              ssidChk=$ssid
+              return 0
+      else
+	      #No Network found, NoSSid issued"
+              echo "No SSid found, assessing WiFi status"
+              ssidChk='NoSSid'
+     fi
+done
+}
+
+NoDevice()
+{
+	#if no wifi device,ie usb wifi removed, activate wifi so when it is
+	#reconnected wifi to a router will be available
+	echo "No wifi device connected"
+	wpa_supplicant -B -i "$wifidev" -c /etc/wpa_supplicant/wpa_supplicant.conf >/dev/null 2>&1
+	exit 1
+}
+
+FindSSID
+
+#Create Hotspot or connect to valid wifi networks
+if [ "$ssidChk" != "NoSSid" ] 
+then
+       if systemctl status hostapd | grep "(running)" >/dev/null 2>&1
+       then #hotspot running and ssid in range
+              KillHotspot
+              echo "Hotspot Deactivated, Bringing Wifi Up"
+              wpa_supplicant -B -i "$wifidev" -c /etc/wpa_supplicant/wpa_supplicant.conf >/dev/null 2>&1
+              ChkWifiUp
+       elif { wpa_cli -i "$wifidev" status | grep 'ip_address'; } >/dev/null 2>&1
+       then #Already connected
+              echo "Wifi already connected to a network"
+       else #ssid exists and no hotspot running connect to wifi network
+              echo "Connecting to the WiFi Network"
+              wpa_supplicant -B -i "$wifidev" -c /etc/wpa_supplicant/wpa_supplicant.conf >/dev/null 2>&1
+              ChkWifiUp
+       fi
+else #ssid or MAC address not in range
+       if systemctl status hostapd | grep "(running)" >/dev/null 2>&1
+       then
+              echo "Hostspot already active"
+       elif { wpa_cli status | grep "$wifidev"; } >/dev/null 2>&1
+       then
+              echo "Cleaning wifi files and Activating Hotspot"
+              wpa_cli terminate >/dev/null 2>&1
+              ip addr flush "$wifidev"
+              ip link set dev "$wifidev" down
+              rm -r /var/run/wpa_supplicant >/dev/null 2>&1
+              createAdHocNetwork
+       else #"No SSID, activating Hotspot"
+              createAdHocNetwork
+       fi
+fi