#!/bin/bash
###############################################################################
#                                                                             #
# IPFire.org - A linux based firewall                                         #
# Copyright (C) 2010  Michael Tremer & Christian Schmidt                      #
#                                                                             #
# This program is free software: you can redistribute it and/or modify        #
# it under the terms of the GNU General Public License as published by        #
# the Free Software Foundation, either version 3 of the License, or           #
# (at your option) any later version.                                         #
#                                                                             #
# This program is distributed in the hope that it will be useful,             #
# but WITHOUT ANY WARRANTY; without even the implied warranty of              #
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the               #
# GNU General Public License for more details.                                #
#                                                                             #
# You should have received a copy of the GNU General Public License           #
# along with this program.  If not, see <http://www.gnu.org/licenses/>.       #
#                                                                             #
###############################################################################

IP_SUPPORTED_PROTOCOLS="${IP_SUPPORTED_PROTOCOLS} ipv4"

function ipv4_is_valid() {
	ipcalc --ipv4 -c $@ >/dev/null 2>&1

	case "$?" in
		0)
			return ${EXIT_OK}
			;;
		*)
			return ${EXIT_ERROR}
			;;
	esac
}

function ipv4_prefix_is_valid() {
	local prefix=${1}

	isset prefix || return ${EXIT_FALSE}

	[ ${prefix} -le  0 ] && return ${EXIT_FALSE}
	[ ${prefix} -gt 32 ] && return ${EXIT_FALSE}

	return ${EXIT_TRUE}
}

function ipv4_netmask_is_valid() {
	local netmask="${1}"

	# XXX this check could be much better by checking
	# if the netmask only contains leading ones

	ipv4_is_valid "${netmask}"
}

function ipv4_detect_duplicate() {
	local device=${1}
	local address=${2}

	assert isset address
	assert isset device
	assert device_exists ${device}

	# Don't check on PPP devices.
	device_is_ppp ${device} && return ${EXIT_ERROR}

	if ! arping -q -c 2 -w 3 -D -I ${device} ${address}; then
		log DEBUG "Detected duplicate address '${address}' on device '${device}'."
		return ${EXIT_OK}
	fi

	return ${EXIT_ERROR}
}

function ipv4_update_neighbours() {
	local device=${1}
	local address=${2}

	# Don't do anything on PPP devices.
	device_is_ppp ${device} && return ${EXIT_OK}

	arping -q -A -c 1 -I ${device} ${address}
	( sleep 2; arping -q -U -c 1 -I ${device} ${address} ) >/dev/null 2>&1 </dev/null &
}

function ipv4_get_netaddress() {
	local address=${1}
	assert isset address

	local prefix=$(ip_get_prefix ${address})
	isset prefix || prefix="32"

	# Assume host-only address if no prefix has been given.
	if [ "${prefix}" = "32" ]; then
		echo "${address}/${prefix}"
		return ${EXIT_OK}
	fi

	local NETWORK
	eval $(ipcalc --network ${address})
	assert isset NETWORK

	echo "${NETWORK}/${prefix}"
	return ${EXIT_OK}
}

function ipv4_get_prefix() {
	local address=${1}
	local broadcast=${2}

	assert isset address
	assert isset broadcast

	local PREFIX
	eval $(ipcalc --prefix ${address} ${broadcast})
	assert isset PREFIX

	echo "${PREFIX}"
	return ${EXIT_OK}
}

function ipv4_get_netmask() {
	local address=${1}
	assert isset address

	# Add prefix if none given.
	local prefix=$(ip_get_prefix ${address})
	isset prefix || address="${address}/32"

	local NETMASK
	eval $(ipcalc --netmask ${address})
	assert isset NETMASK

	print "${NETMASK}"
	return ${EXIT_OK}
}

function ipv4_flush_device() {
	#
	# Flushes all routes, addresses from the device
	# and clears the ARP cache.
	#

	local device=${1}
	assert isset device

	ip -4 addr flush dev ${device} >/dev/null 2>&1
	ip -4 route flush dev ${device} >/dev/null 2>&1
	ip -4 neigh flush dev ${device} >/dev/null 2>&1

	return 0
}

function ipv4_prefix2netmask() {
	local prefix=${1}
	shift

	assert isinteger prefix

	# XXX this function is a stub

	case "${prefix}" in
		24)
			echo "255.255.255.0"
			;;
		*)
			assert false NOT IMPLEMENTED
			;;
	esac
}

function ipv4_netmask2prefix() {
	local netmask="${1}"
	assert isset netmask

	local mask=0

	local field
	for field in ${netmask//\./ }; do
		mask=$(( $(( ${mask} << 8 )) | ${field} ))
	done

	local cidr=0
	local x="$(( 128 << 24 ))" # 0x80000000

	while [ $(( ${x} & ${mask} )) -ne 0 ]; do
		[ ${mask} -eq ${x} ] && mask=0 || mask=$(( ${mask} << 1 ))
		cidr=$(( ${cidr} + 1 ))
	done

	assert [ $(( ${mask} & 2147483647 )) -eq 0 ]

	print "${cidr}"
}

function ipv4_get_network() {
	local network=$(ipv4_get_network $@)

	ipv4_decode ${network}
}

function ipv4_get_network_encoded() {
	local net=${1}

	local prefix=$(ip_get_prefix ${net})
	isset prefix || prefix=32

	local mask=0
	if [ ${prefix} -ne 0 ]; then
		mask=$(( -1 << $(( 32 - ${prefix} )) ))
	fi

	local addr=$(ip_split_prefix ${net})
	addr=$(ipv4_encode ${addr})

	print "%d" $(( ${addr} & ${mask} ))
}

function ipv4_get_broadcast() {
	local broadcast=$(ipv4_get_broadcast_encoded $@)

	ipv4_decode ${broadcast}
}

function ipv4_get_broadcast_encoded() {
	local net=${1}

	local prefix=$(ip_get_prefix ${net})
	assert isset prefix

	prefix=$(( 32 - ${prefix} ))

	local netmask=0
	local broadcast=-1
	if [ ${prefix} -eq 32 ]; then
		:
	else
		netmask=$(( -1 << ${prefix} ))
		broadcast=$(( $(( 1 << ${prefix} )) - 1))
	fi

	local addr=$(ip_split_prefix ${net})
	addr=$(ipv4_encode ${addr})

	print "%d" $(( $(( ${addr} & ${netmask} )) | ${broadcast} ))
}

function ipv4_encode() {
	local addr=${1}
	local int=0

	local field
	for field in ${addr//./ }; do
		int=$(( $(( ${int} << 8 )) | ${field} ))
	done

	print "${int}"
}

function ipv4_decode() {
	local int=${1}

	local addr=$(( ${int} & 255 ))

	local i
	for i in 1 2 3; do
		int=$(( ${int} >> 8 ))
		addr="$(( ${int} & 255 )).${addr}"
	done

	print "${addr}"
}

function ipv4_addr_eq() {
	local addr1=${1}
	assert isset addr1

	local addr2=${2}
	assert isset addr2

	[[ "${addr1}" = "${addr2}" ]] \
		&& return ${EXIT_TRUE} || return ${EXIT_FALSE}
}

function ipv4_addr_gt() {
	local addr1=${1}
	assert isset addr1

	local addr2=${2}
	assert isset addr2

	local addr
	for addr in addr1 addr2; do
		printf -v ${addr} "%s" "$(ip_encode ${!addr})"
	done

	[[ ${addr1} -gt ${addr2} ]] \
		&& return ${EXIT_TRUE} || return ${EXIT_FALSE}
}

function ipv4_range() {
	local range=${1}

	local first=${1%-*}
	local last=${1#*-}

	_ipv4_range "$(ipv4_encode ${first})" "$(ipv4_encode ${last})"
}

function _ipv4_range() {
	local first=${1}
	local last=${2}

	if [ ${first} -gt ${last} ]; then
		local range="$(ipv4_decode ${first})-$(ipv4_decode ${last})"

		error "Invalid IPv4 address range: ${range}"
		return ${EXIT_ERROR}
	fi

	last=$(( ${last} + 1 ))

	local prefix
	local x y z
	while [ ${last} -gt ${first} ]; do
		prefix=
		x=31
		y=2
		z=1

		while [ $(( ${first} % ${y} )) -eq 0 ] && [ ${last} -gt $(( ${first} + ${y} )) ]; do
			prefix="/${x}"
			x=$(( ${x} - 1 ))
			z=${y}
			y=$(( ${y} * 2 ))
		done

		print "$(ipv4_decode ${first})${prefix}"
		first=$(( ${first} + ${z} ))
	done
}

function ipv4_range_explicit() {
	local range=${1}

	local first last

	case "${range}" in
		*.*.*.*-*.*.*.*)
			first=${range%-*}
			last=${range#*-}
			;;
		*.*.*.*/*)
			first=$(ipv4_get_network ${range})
			last=$(ipv4_get_broadcast ${range})
			;;
	esac

	_ipv4_range_explicit "$(ipv4_encode ${first})" "$(ipv4_encode ${last})"
}

function _ipv4_range_explicit() {
	local first=${1}
	local last=${2}

	if [ ${first} -gt ${last} ]; then
		local range="$(ipv4_decode ${first})-$(ipv4_decode ${last})"

		error "Invalid IPv4 address range: ${range}"
		return ${EXIT_ERROR}
	fi

	while [ ${first} -le ${last} ]; do
		ipv4_decode ${first}
		first=$(( ${first} + 1 ))
	done
}

function ipv4_in_subnet() {
	local addr=${1}
	assert isset addr

	local subnet=${2}
	assert isset subnet

	local subnet_first=$(ipv4_get_network_encoded ${subnet})
	local subnet_last=$(ipv4_get_broadcast_encoded ${subnet})

	addr=$(ipv4_encode ${addr})

	if [[ "${addr}" -ge "${subnet_first}" ]] && [[ "${addr}" -le "${subnet_last}" ]]; then
		return ${EXIT_TRUE}
	fi

	return ${EXIT_FALSE}
}

function ipv4_ttl_valid() {
	local ttl="${1}"

	isinteger ttl || return ${EXIT_FALSE}

	# Must be between 10 and 255.
	[ "${ttl}" -lt  10 ] && return ${EXIT_FALSE}
	[ "${ttl}" -gt 255 ] && return ${EXIT_FALSE}

	return ${EXIT_TRUE}
}