#!/bin/sh

# this script will work with eth0
INTERNET_IFACE=eth0
# should be wireless
MOBILE_IFACE=wlan0
# your network name your mobile will connect to
MOBILE_ESSID="Mobile Router"

# Configure your dhcp server !

# dhcp client (for internet interface) : this script uses dhcpcd
# dhcp server (for mobile interface) : this script uses dhcpd

if [ "${UID}" != "0" ]; then
  echo "You should be root to run this program"
  echo "Hint : sudo $0"
  exit 1
fi

# Step 1 : halt scripts
/etc/init.d/NetworkManager stop &> /dev/null
/etc/init.d/wicd stop &> /dev/null

sleep 2

# Step 2 : internet connection
dhcpcd -b ${INTERNET_IFACE}
iptables -t nat -A POSTROUTING -o ${INTERNET_IFACE} -j MASQUERADE
sysctl net.ipv4.ip_forward=1

# Step 3 : wifi connection
iwconfig ${MOBILE_IFACE} mode ad-hoc essid "${MOBILE_ESSID}"
ifconfig ${MOBILE_IFACE} 10.10.10.1 up

# Step 3b : dhpd
/etc/init.d/dhcpd start

# Wait for closing
echo "Press Ctrl-D to stop sniffing"
cat

# Step -3b
/etc/init.d/dhcpd stop
# Step -3
# Step -2
iptables -t nat -D POSTROUTING -o ${INTERNET_IFACE} -j MASQUERADE
sysctl net.ipv4.ip_forward=0
dhcpcd -k ${INTERNET_IFACE}
# Step -1
/etc/init.d/NetworkManager start &> /dev/null
/etc/init.d/wicd start &> /dev/null

echo Sniff finished