adhoc.sh

#!/bin/sh
# Copyright (c) 2010 Rex Tsai <chihchun@kalug.linux.org.tw>
# 
# Description
# * Setup wlan0 as ad-hoc interface
# * make eth0 as gateway, change it if you like to use other inteface like ppp0
#
# INIC
# ONIC
WLAN=wlan0
ROUTE=eth0

# /etc/init.d/shorewall restart
# we don't want network manager to manage networks
# /etc/init.d/network-manager stop

sysctl -w net.ipv4.conf.all.forwarding=1
sysctl -w net.ipv4.conf.default.forwarding=1

iptables -I INPUT 1 -i ${WLAN} -d 10.8.8.1 -p udp --dport 53 -j ACCEPT
iptables -A FORWARD -i ${WLAN} -o ${ROUTE} -s 10.8.8.0/24 -m conntrack --ctstate NEW -j ACCEPT
iptables -A FORWARD -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
iptables -A POSTROUTING -t nat -j MASQUERADE

# transparent proxy
# iptables -t nat -A PREROUTING -i ${WLAN} -p tcp --dport 80 -j REDIRECT --to-port 3128
# iptables -I INPUT 1 -i ${WLAN} -d 10.8.8.1 -p 3128 --dport tcp -j ACCEPT

# DNAT settings
# iptables -t nat -A PREROUTING -i ${WLAN} -p tcp --dport 1194 -j DNAT --to-destination 192.168.2.2
# iptables -t nat -A PREROUTING -i ${WLAN} -p udp -m multiport --dports 53,1194 -j DNAT --to-destination 192.168.2.2
# iptables -A FORWARD -i ${WLAN} -d 192.168.2.2 -p tcp --dport 1194 -j ACCEPT
# iptables -A FORWARD -i ${WLAN} -d 192.168.2.2 -p udp -m multiport --dports 53,1194 -j ACCEPT

ifconfig ${WLAN} down
iwconfig ${WLAN} mode ad-hoc
iwconfig ${WLAN} essid rex
ifconfig ${WLAN} 10.8.8.1
ifconfig ${WLAN} up

# DNS + DHCP
dnsmasq --listen-address=10.8.8.1 \
    --interface=${WLAN} \
    --dhcp-range=10.8.8.100,10.8.8.200,1h \
    --no-daemon \
    --log-dhcp \
    --log-queries \
    --enable-dbus --all-servers \
    -i ${WLAN}