create_ap

create a nat-ed wifi ap
git clone git://git.2f30.org/create_ap.git
Log | Files | Refs | LICENSE

commit a336acd7cc0d8f01a2b18d725726d0473eeea23b
parent 513f1fce1994400c71299776d99335d4372f219d
Author: oblique <psyberbits@gmail.com>
Date:   Mon Nov 18 02:38:05 +0200

Add -m option, now you can choose NATed (default) or bridged Internet sharing (thanks batnas)

Diffstat:
create_ap | 161+++++++++++++++++++++++++++++++++++++++++++++++++++++++------------------------
1 file changed, 112 insertions(+), 49 deletions(-)
diff --git a/create_ap b/create_ap @@ -4,10 +4,12 @@ # bash (to run this script) # util-linux (for getopt) # hostapd -# dnsmasq -# iptables # iproute2 # haveged (optional) +# dnsmasq (needed for 'nat' or 'none' Internet sharing method) +# iptables (needed for 'nat' Internet sharing method) +# bridge-utils (needed for 'bridge' Internet sharing method) +# dhclient (needed for 'bridge' Internet sharing method) usage() { echo "Usage: $(basename $0) [options] <wifi-interface> [<interface-with-internet>] [<access-point-name> [<passphrase>]]" @@ -16,24 +18,40 @@ usage() { echo " -h, --help Show this help" echo " -c <channel> Channel number (default: 1)" echo " -w <WPA version> Use 1 for WPA, use 2 for WPA2, use 1+2 for both (default: 1+2)" - echo " -g <gateway> IPv4 Gateway for the Access Point (default: 192.168.12.1)" - echo " -d DNS server will take into account /etc/hosts" echo " -n Disable Internet sharing (if you use this, don't pass" echo " the <interface-with-internet> argument)" + echo " -m <method> Method for Internet sharing." + echo " Use: 'nat' for NAT (default)" + echo " 'bridge' for bridging" + echo " 'none' for no Internet sharing (equivalent to -n)" echo " --hidden Make the Access Point hidden (do not broadcast the SSID)" echo + echo "Non-Bridging Options:" + echo " -g <gateway> IPv4 Gateway for the Access Point (default: 192.168.12.1)" + echo " -d DNS server will take into account /etc/hosts" + echo echo "Examples:" echo " $(basename $0) wlan0 eth0 MyAccessPoint MyPassPhrase" echo " $(basename $0) -n wlan0 MyAccessPoint MyPassPhrase" + echo " $(basename $0) -m bridge wlan0 eth0 MyAccessPoint MyPassPhrase" echo " echo -e 'MyAccessPoint\nMyPassPhrase' | $(basename $0) wlan0 eth0" - echo " echo -e 'MyAccessPoint\nMyPassPhrase' | $(basename $0) -n wlan0" } get_macaddr() { - ip link show "$1" | sed -n 's/.*ether \([0-9a-f][0-9a-f]:[0-9a-f][0-9a-f]:[0-9a-f][0-9a-f]:[0-9a-f][0-9a-f]:[0-9a-f][0-9a-f]:[0-9a-f][0-9a-f]\) .*/\1/p' + ip link show "$1" | grep ether | grep -Eo '([0-9a-f]{2}:){5}[0-9a-f]{2}\s' +} + +get_avail_bridge() { + for i in {1..100}; do + curr_bridge=$(brctl show | grep "br$i" | cut -s -f1) + if [[ -z $curr_bridge ]]; then + echo "br$i" + return + fi + done } -ARGS=$(getopt -o hc:w:g:dn -l "help","hidden" -n $(basename $0) -- "$@") +ARGS=$(getopt -o hc:w:g:dnm: -l "help","hidden" -n $(basename $0) -- "$@") [[ $? -ne 0 ]] && exit 1 eval set -- "$ARGS" @@ -42,7 +60,7 @@ GATEWAY=192.168.12.1 WPA_VERSION=1+2 ETC_HOSTS=0 HIDDEN=0 -SHARE_INTERNET=1 +SHARE_METHOD=nat while :; do case "$1" in @@ -56,24 +74,18 @@ while :; do ;; -c) shift - if [[ -n "$1" ]]; then - CHANNEL="$1" - shift - fi + CHANNEL="$1" + shift ;; -w) shift - if [[ -n "$1" ]]; then - WPA_VERSION="$1" - shift - fi + WPA_VERSION="$1" + shift ;; -g) shift - if [[ -n "$1" ]]; then - GATEWAY="$1" - shift - fi + GATEWAY="$1" + shift ;; -d) shift @@ -81,7 +93,12 @@ while :; do ;; -n) shift - SHARE_INTERNET=0 + SHARE_METHOD=none + ;; + -m) + shift + SHARE_METHOD="$1" + shift ;; --) shift @@ -95,10 +112,35 @@ if [[ $# -lt 1 ]]; then exit 1 fi +if [[ $(id -u) -ne 0 ]]; then + echo "You must run it as root." + exit 1 +fi + +if [[ "$SHARE_METHOD" != "nat" && "$SHARE_METHOD" != "bridge" && "$SHARE_METHOD" != "none" ]]; then + echo "ERROR: Wrong Internet sharing method" + echo + usage + exit 1 +fi + WIFI_IFACE=$1 +if [[ "$SHARE_METHOD" == "bridge" ]]; then + BRIDGE_IFACE=$(get_avail_bridge) + if [[ -z $BRIDGE_IFACE ]]; then + echo "ERROR: No availabe bridges < br100" + exit 1 + fi +fi + +if [[ "$SHARE_METHOD" != "none" ]]; then + MIN_REQUIRED_ARGS=2 +else + MIN_REQUIRED_ARGS=1 +fi -if [[ $# -gt 2 ]]; then - if [[ $SHARE_INTERNET -eq 1 ]]; then +if [[ $# -gt $MIN_REQUIRED_ARGS ]]; then + if [[ "$SHARE_METHOD" != "none" ]]; then if [[ $# -ne 3 && $# -ne 4 ]]; then usage exit 1 @@ -115,7 +157,7 @@ if [[ $# -gt 2 ]]; then PASSPHRASE=$3 fi else - if [[ $SHARE_INTERNET -eq 1 ]]; then + if [[ "$SHARE_METHOD" != "none" ]]; then if [[ $# -ne 2 ]]; then usage exit 1 @@ -141,11 +183,6 @@ else fi fi -if [[ $(id -u) -ne 0 ]]; then - echo "You must run it as root." - exit 1 -fi - CONFDIR=$(mktemp -d /tmp/create_ap.${WIFI_IFACE}.conf.XXXXXXXX) echo "Config dir: $CONFDIR" @@ -175,28 +212,42 @@ rsn_pairwise=CCMP EOF fi -# dnsmasq config (dhcp + dns) -cat << EOF > $CONFDIR/dnsmasq.conf +if [[ "$SHARE_METHOD" == "bridge" ]]; then + echo "bridge=${BRIDGE_IFACE}" >> $CONFDIR/hostapd.conf +else + # dnsmasq config (dhcp + dns) + cat << EOF > $CONFDIR/dnsmasq.conf interface=${WIFI_IFACE} bind-interfaces dhcp-range=${GATEWAY%.*}.1,${GATEWAY%.*}.254,255.255.255.0,24h dhcp-option=option:router,${GATEWAY} EOF + [[ $ETC_HOSTS -eq 0 ]] && echo no-hosts >> $CONFDIR/dnsmasq.conf +fi -[[ $ETC_HOSTS -eq 0 ]] && echo no-hosts >> $CONFDIR/dnsmasq.conf - -# enable interface +# setup WiFi interface ip link set down dev ${WIFI_IFACE} ip addr flush ${WIFI_IFACE} -ip link set up dev ${WIFI_IFACE} -ip addr add ${GATEWAY}/24 dev ${WIFI_IFACE} - -# enable NATed Internet sharing -if [[ $SHARE_INTERNET -eq 1 ]]; then - iptables -t nat -A POSTROUTING -o ${INTERNET_IFACE} -j MASQUERADE - iptables -A FORWARD -i ${WIFI_IFACE} -j ACCEPT - OLD_IP_FORWARD=$(cat /proc/sys/net/ipv4/ip_forward) - echo 1 > /proc/sys/net/ipv4/ip_forward +if [[ "$SHARE_METHOD" != "bridge" ]]; then + ip link set up dev ${WIFI_IFACE} + ip addr add ${GATEWAY}/24 dev ${WIFI_IFACE} +fi + +# enable Internet sharing +if [[ "$SHARE_METHOD" != "none" ]]; then + echo "Sharing Internet using method: $SHARE_METHOD" + if [[ "$SHARE_METHOD" == "nat" ]]; then + iptables -t nat -A POSTROUTING -o ${INTERNET_IFACE} -j MASQUERADE + iptables -A FORWARD -i ${WIFI_IFACE} -j ACCEPT + OLD_IP_FORWARD=$(cat /proc/sys/net/ipv4/ip_forward) + echo 1 > /proc/sys/net/ipv4/ip_forward + elif [[ "$SHARE_METHOD" == "bridge" ]]; then + brctl addbr ${BRIDGE_IFACE} + brctl addif ${BRIDGE_IFACE} ${INTERNET_IFACE} + dhclient -pf $CONFDIR/dhclient.pid ${BRIDGE_IFACE} + fi +else + echo "No Internet sharing" fi # boost low-entropy @@ -207,7 +258,9 @@ if [[ $(cat /proc/sys/kernel/random/entropy_avail) -lt 1000 ]]; then fi # start dns + dhcp server -dnsmasq -C $CONFDIR/dnsmasq.conf -x $CONFDIR/dnsmasq.pid +if [[ "$SHARE_METHOD" != "bridge" ]]; then + dnsmasq -C $CONFDIR/dnsmasq.conf -x $CONFDIR/dnsmasq.pid +fi # start access point echo "hostapd command-line interface: hostapd_cli -p $CONFDIR/hostapd_ctrl" @@ -223,15 +276,25 @@ hostapd $CONFDIR/hostapd.conf || { echo } +echo +echo "Doing cleanup..." + # exiting for x in $CONFDIR/*.pid; do - kill -9 $(cat $x) + # even if the $CONFDIR is empty, the for loop will assign + # a value in $x. so we need to check if the value is a file + [[ -f $x ]] && kill -9 $(cat $x) done rm -rf $CONFDIR -if [[ $SHARE_INTERNET -eq 1 ]]; then - iptables -t nat -D POSTROUTING -o ${INTERNET_IFACE} -j MASQUERADE - iptables -D FORWARD -i ${WIFI_IFACE} -j ACCEPT - echo $OLD_IP_FORWARD > /proc/sys/net/ipv4/ip_forward +if [[ "$SHARE_METHOD" != "none" ]]; then + if [[ "$SHARE_METHOD" == "nat" ]]; then + iptables -t nat -D POSTROUTING -o ${INTERNET_IFACE} -j MASQUERADE + iptables -D FORWARD -i ${WIFI_IFACE} -j ACCEPT + echo $OLD_IP_FORWARD > /proc/sys/net/ipv4/ip_forward + elif [[ "$SHARE_METHOD" == "bridge" ]]; then + ip link set down $BRIDGE_IFACE + brctl delbr $BRIDGE_IFACE + fi fi ip link set down dev ${WIFI_IFACE} ip addr flush ${WIFI_IFACE}