Start dnsmaq when connected to wifi

dnsmasq-wlan

#!/bin/bash

# Write file /etc/network/if-up.d/ and link to /etc/network/if-post-down.d/
# by default, scripts on that directories will be triggered by NetworkManager

PID="/var/run/dnsmasq/wlan.pid"
WLAN="wlan0"
DNSMASQCONF="/etc/dnsmasq.conf"
IP=$(ifconfig $WLAN | sed -En 's/.*inet ([0-9\\.]+) .+/\1/p')
ME="$IFACE-dnsmasq:"

#echo "$ME Triggered by $IFACE" > /dev/kmsg

[ "$IFACE" = "$WLAN" ] || exit 0

echo "$ME $MODE $IP" > /dev/kmsg
#Remove interface & listen address and replace loopback
CONFIG=`sed "s/^interface=.*//; s/^listen-address=.*//; s/127.0.0.1/$IP/" /etc/dnsmasq.conf`

if [ "$MODE" = "start" ]; then
    if [ -f "$PID" ]; then
        # Already running
        echo "$ME Canceled, pid exists $PID" > /dev/kmsg
        exit 1
    fi

    echo "$CONFIG" | dnsmasq -C - \
        --bind-interfaces \
        --except-interface=lo \
        --interface=$WLAN \
        --listen-address=$IP \
        --pid-file=$PID &> /dev/kmsg

elif [ "$MODE" = "stop" ]; then
    if [ -f "$PID" ]; then
        # Already running
        kill `cat $PID` > /dev/kmsg
        unlink $PID
    else
        echo "$ME No Pid found" > /dev/kmsg
    fi
fi