#!/bin/sh
# use gainroot to become root and relaunch itself
if [ `id -u` != 0 ] ; then
#if not already root, call itself as root
        exec sudo gainroot <<EOF
exec $0 $*
EOF
        exit $?
fi
# real script follows

#BT MAC of PC/phone
BTADDR='00:09:DD:60:11:B6'
#bluetooth name of PC/phone, not important, just for infoprints
BTNAME="DH9JYJ2J"
#desired IP address of your tablet
IP=192.168.0.4
#default gateway - IP address of PC/phone
GW=192.168.0.3 
#DNS server
NS=10.6.101.1
# remote PAN role, one of NAP, GN
PAN_ROLE=GN 

infoprint(){
DBUS_SESSION_BUS_ADDRESS='unix:path=/tmp/session_bus_socket' dbus-send --session --print-reply --dest=org.freedesktop.Notifications /org/freedesktop/Notifications org.freedesktop.Notifications.SystemNoteInfoprint "string:$*" &
}

dbus_method(){
local dest=$1
shift
DBUS_REPLY=$(dbus-send 2>&1 --system --type=method_call --print-reply --dest="$dest" $* )
}

dbus_result(){
echo $DBUS_REPLY | cut -d ' ' -f 7 | tr -d \"
}

find_connection(){
#find or create connection
if dbus_method org.bluez /org/bluez org.bluez.Manager.ActivateService string:network ; then
    NET_BUS=$(dbus_result)
#    echo destination $NET_BUS
    if dbus_method "${NET_BUS}" /org/bluez/network org.bluez.network.Manager.FindConnection string:"${BTADDR}" ; then
        CONN=$(dbus_result)
    else
        if dbus_method "${NET_BUS}" /org/bluez/network org.bluez.network.Manager.CreateConnection string:"${BTADDR}" string:"$PAN_ROLE" ; then
        CONN=$(dbus_result)
        fi
    fi
fi
}


bnep_start(){
#find_connection
if [ "$CONN" != "" ] ; then
echo connection $CONN
if dbus_method "${NET_BUS}" ${CONN} org.bluez.network.Connection.Connect ; then
    BNEPDEV=$(dbus_result)
    echo connected to $BNEPDEV
    ifconfig $BNEPDEV $IP up
    if route -n | grep -q '^0.0.0.0' ; then
        echo "default gateway already set, skipping GW and DNS setting"
    else
        route add default gw $GW
        echo "nameserver $NS" >/tmp/resolv.conf.lo
    fi
    [ -t 1 ] || infoprint "Connected to $BTNAME"
fi
fi
}

bnep_stop(){
#find_connection
if [ "$CONN" != "" ] ; then
echo connection $CONN
if dbus_method "${NET_BUS}" ${CONN} org.bluez.network.Connection.Disconnect ; then
echo "OK, bringing down"
echo -n '' >/tmp/resolv.conf.lo
[ -t 1 ] || infoprint "$BTNAME disconnected"
fi
fi
}

echo "Searching for $BTADDR ..."
[ -t 1 ] || infoprint "Searching for $BTADDR"
find_connection
if [ "$CONN" = "" ] ; then
    echo $DBUS_REPLY
    echo "Setting up connection to $BTADDR failed"
    [ -t 1 ] || infoprint "Connection to $BTADDR failed"
    exit
fi

COMMAND=$1
if [ "$COMMAND" = "" ] ; then
    dbus_method "${NET_BUS}" ${CONN} org.bluez.network.Connection.IsConnected
    if [ "$(dbus_result)" = "true" ] ; then
        COMMAND=stop
    else
        COMMAND=start
    fi
fi

case $COMMAND in
    start)      bnep_start ;;
    stop)       bnep_stop ;;
esac