Open AP on Linux

netAP

#!/bin/bash

###########################################
#This shell is modified from Leon Lee, or-#
#iginal version see here:                 #
#                                         #
#https://gist.github.com/anonymous/1117004#
#                                         #
#                                         #
#Notice: To run this shell, you should in-#
#stall hostapd and dnsmasq first.         #
#                                         #
#For example(archlinux):                  #
#sudo pacman -S hostapd dnsmasq           #
#                                         #
#If you have any question, please mail to #
#[email protected].                     #
###########################################

ShareNet=enp7s0
WInterface=wlp8s0
Igateway=192.168.2.254
Inetmask=255.255.255.0
Inetwork=192.168.2.0
DhcpRangeMin=192.168.2.10
DhcpRangeMax=192.168.2.105
###########################################

AP_Folder=/etc/AP
hostapdFile=/etc/hostapd/hostapd.conf
dnsmasqFile=$AP_Folder/dnsmasq.conf
resolvFile=/etc/resolv.conf
dnsmasqPid=/var/run/dnsmasq.pid
dnsmasqLeases=/var/run/dnsmasq.leases
############################################

# start AP
function AP_start
{
	echo "Starting AP..."
	check_dnsmasq
	sleep 1
	sudo ifconfig $WInterface down
	echo -n "Setting $WInterface gateway and netmask."
	sudo ifconfig $WInterface $Igateway netmask $Inetmask
	sleep 1
	echo
	
	echo -n "Setting up $WInterface ..."
	sudo ifconfig $WInterface up
	sudo hostapd $hostapdFile -B
	sleep 1
	echo
	
	echo -n "Setting iptable..."
	sleep 1
	
	#remove the old rules
	sudo iptables -N wireless-AP
  	sudo iptables -F wireless-AP
  	sudo iptables -t nat -F PREROUTING
  	sudo iptables -t nat -F POSTROUTING
  	sudo iptables -t nat -F

	#bring up the NAT rules
	sudo iptables -A wireless-AP -m state --state ESTABLISHED,RELATED -j ACCEPT
	sudo iptables -A wireless-AP -s $Inetwork/24 -j ACCEPT
	sudo iptables -A wireless-AP -p 47 -j ACCEPT
	sudo iptables -A wireless-AP -j DROP
	sudo iptables -A FORWARD -m state --state INVALID -j DROP
	sudo iptables -A FORWARD -j wireless-AP
	sudo iptables -t nat -I POSTROUTING -s $Inetwork/24 -j MASQUERADE
	sleep 1
	sudo sh -c "echo 1 > /proc/sys/net/ipv4/ip_forward"
	echo -n "."
	sleep 1
	sudo dnsmasq -i $WInterface --resolv-file=$resolvFile --conf-file=$dnsmasqFile
	echo
	echo "Success"
}

# stop AP
function AP_stop
{
	echo "Stopping AP ..."
	sudo sh -c "echo 0 > /proc/sys/net/ipv4/ip_forward"
	echo -n "."
	sudo ifconfig $WInterface down
	sudo pkill hostapd
	sleep 1
	# remove iptabled rules
	sudo iptables -D FORWARD -j wireless-AP
	sudo iptables -D FORWARD -m state --state INVALID -j DROP
	sudo iptables -F wireless-AP
	sudo iptables -X wireless-AP
	sudo iptables -t nat -F PREROUTING
	sudo iptables -t nat -F POSTROUTING
	sudo iptables -t nat -F
	sleep 1
	if [ -f $dnsmasqPid ]; then
		dnsmasqID=`cat $dnsmasqPid`
		kill $dnsmasqID
		sleep 1
	fi
	if [ -f $dnsmasqLeases ]; then 
		rm $dnsmasqLeases
	fi
	echo
	echo "Wifi AP now stopped"
}

# restart AP
function AP_restart
{
	echo "Now, resart AP ..."
	AP_stop
	sleep 2
	AP_start
}

# check dnsmasq.conf
function check_dnsmasq
{
 
	if [ -f $dnsmasqPid ]; then
		echo "Dhcp is running!"
		echo "Now, restart AP"
		AP_stop
		sleep 1
	fi
	if [ ! -d $AP_Folder ]; then
	mkdir $AP_Folder
	fi
 
	if [ ! -f $dnsmasqFile ]; then
	echo "$dnsmasqFile is not exist, now building."
 
	echo "dhcp-authoritative" > $dnsmasqFile
	echo "dhcp-range=$DhcpRangeMin,$DhcpRangeMax,12h" >> $dnsmasqFile
	echo "dhcp-leasefile=$dnsmasqLeases" >> $dnsmasqFile
	echo "pid-file=$dnsmasqPid" >> $dnsmasqFile
	echo "user=root" >> $dnsmasqFile
	echo "no-negcache" >> $dnsmasqFile
	fi
}
 
# is super user?
function super_user
{
	if [ "$UID" = "0" ]; then
	return 0
	else
	return 1
	fi
}
 
function usage
{
	echo "Wifi AP control"
	echo "$1 [-h][-s]"
	echo "Default is start AP"
	echo "-h show the usage"
	echo "-s stop AP"
	echo "-r restart AP"
}
 
if ! super_user ; then
echo "Need super user permission!"
exit 1
fi
if [ $# -lt 1 ]; then
AP_start
elif [ "$1" = "-h" ]; then
usage
elif [ "$1" = "-s" ]; then
AP_stop
elif [ "$1" = "-r" ]; then
AP_restart
else
echo "Input error!"
echo "$1 -h gives usage information."
fi