#!/bin/sh
#
# This file is part of the FreeWRT project. FreeWRT is copyrighted
# material, please see the LICENCE file in the top-level directory
# or at http://www.freewrt.org/licence for details.
#
# Christian Fischer <spaetzle@freewrt.org>
#

CFG_DOWN_IFUP_CHECK_OFF=1
CFG_STOP_PRINTING_OFF=1

iface_type() {
	# HACK: use iface name only, no idea how to get the list of existing tuntap ifaces
	# from system
	if 	check_iface_name || \
		[ "${IF_TUNTAP:-""}" != "" ] || \
		[ "${IF_TUNTAP_USER:-""}" != "" ]
	then
		return 0
	fi
	return 1
}

check_iface_name() {
	echo $IFACE | grep -q "^tun\|^tap[0-9][1-9]*$" 
}

check_kernel_support() {
	[ -e /dev/net/tun ] && return
	insmod tun >/dev/null 2>&1 ; sleep 1
	[ -e /dev/net/tun ] && return
	err="Your kernel lacks tuntap support"
	return 1
}

check_openvpn_support() {
	[ -x "$(which openvpn)" ] && return
	err="openvpn executable not found"
	return 1
}

check_tunctl_support() {
	[ -x "$(which tunctl)" ] && return
	err="tunctl executable not found"
	return 1
}

openvpn_create() {
	openvpn --mktun --dev $IFACE >/dev/null 2>&1 && return
	err="Creating openvpn tuntap $IFACE failed"
	return 1
}

tunctl_create() {
	tunctl -u ${IF_TUNTAP_USER:-0} -t $IFACE >/dev/null 2>&1 && return
	err="Creating tuntap $IFACE failed"
	return 1
}

openvpn_destroy() {
	openvpn --rmtun --dev $IFACE >/dev/null 2>&1 && return
	err="Destroying openvpn tuntap $IFACE failed"
	return 1
}

tunctl_destroy() {
	tunctl -d "${IFACE}" >/dev/null 2>&1 && return
	err="Destroying tuntap $IFACE failed"
	return 1
}

tuntap_create() {
	eval $fncreate
}

tuntap_destroy() {
	eval $fndestroy
}

set_methods() {
	if [ "${IF_TUNTAP:-""}" = "openvpn" ]
	then
		check_openvpn_support || return 1
		fncreate="openvpn_create"
		fndestroy="openvpn_destroy"
	else
		check_tunctl_support || return 1
		fncreate="tunctl_create"
		fndestroy="tunctl_destroy"
	fi
	return 0
}

if_preup() {
	check_iface_name || {
		mcreate
		mstate 1
		merr "Tuntap name $IFACE is not supported, use tun* or tap* instead"
		return 1
	}

	if ! check_kernel_support
	then
		mcreate
		mstate 1
		merr $err
	fi

	if ! set_methods
	then
		mcreate
		mstate 1
		merr $err
	fi
	
	if iface_exists
	then
		mdestroy
		tuntap_destroy
		mstate $? || {
			merr $err
			return 1
		}
	fi

	mcreate
	tuntap_create
	mstate $? || {
		merr $err
		return 1
	}
}

if_down() {
    mstop
	check_iface_name || {
		mdestroy
		mstate 1
		merr "Tuntap name $IFACE is not supported, use tun* or tap* instead"
		return 1
	}

	if ! set_methods
	then
		mdestroy
		mstate 1
		merr $err
	fi

	if ! is_up
	then
		mdestroy
		tuntap_destroy
		mstate $? || merr $err
		builtin exit 1
	fi
	mdown
}

if_postdown() {
	is_up && {
		mstate 1
		return 1
	}
	mstate 0

	if ! set_methods
	then
		mdestroy
		mstate 1
		merr $err
	fi

	mdestroy
	tuntap_destroy
	mstate $? || {
		merr $err
		return 1
	}
}

# vim:ts=4