#!/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"

ipv4_is_valid() {
	local address=${1}

	local prefix=$(ip_get_prefix ${address})
	address=$(ip_split_prefix ${address})

	# If prefix is set, we check if it is correct
	if isset prefix; then
		# Must be numeric
		isinteger prefix || return ${EXIT_FALSE}

		# Must be 32 if present
		[ ${prefix} -eq 32 ] || return ${EXIT_FALSE}
	fi

	inetcalc -4 -c ${address} && return ${EXIT_TRUE} || return ${EXIT_FALSE}
}

ipv4_prefix_is_valid() {
	local prefix=${1}

	# Check if prefix is a number
	isinteger prefix || return ${EXIT_FALSE}

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

	return ${EXIT_TRUE}
}

ipv4_net_is_valid() {
	local net="${1}"

	local prefix="$(ip_get_prefix "${net}")"
	local addr="$(ip_split_prefix "${net}")"

	ipv4_prefix_is_valid "${prefix}" && ipv4_is_valid "${addr}"
}

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}"
}

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}
}

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 &
}

ipv4_calculate_prefix() {
	assert [ $# -eq 2 ]

	local address="${1}"
	local broadcast="${2}"

	inetcalc -4 -p "${address}" "${broadcast}"
}

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
}

ipv4_prefix2netmask() {
	local prefix="${1}"

	case "${prefix}" in
		32)
			echo "255.255.255.255"
			;;
		31)
			echo "255.255.255.254"
			;;
		30)
			echo "255.255.255.252"
			;;
		29)
			echo "255.255.255.248"
			;;
		28)
			echo "255.255.255.240"
			;;
		27)
			echo "255.255.255.224"
			;;
		26)
			echo "255.255.255.192"
			;;
		25)
			echo "255.255.255.128"
			;;
		24)
			echo "255.255.255.0"
			;;
		23)
			echo "255.255.254.0"
			;;
		22)
			echo "255.255.252.0"
			;;
		21)
			echo "255.255.248.0"
			;;
		20)
			echo "255.255.240.0"
			;;
		19)
			echo "255.255.224.0"
			;;
		18)
			echo "255.255.192.0"
			;;
		17)
			echo "255.255.128.0"
			;;
		16)
			echo "255.255.0.0"
			;;
		15)
			echo "255.254.0.0"
			;;
		14)
			echo "255.252.0.0"
			;;
		13)
			echo "255.248.0.0"
			;;
		12)
			echo "255.240.0.0"
			;;
		11)
			echo "255.224.0.0"
			;;
		10)
			echo "255.192.0.0"
			;;
		9)
			echo "255.128.0.0"
			;;
		8)
			echo "255.0.0.0"
			;;
		7)
			echo "254.0.0.0"
			;;
		6)
			echo "252.0.0.0"
			;;
		5)
			echo "248.0.0.0"
			;;
		4)
			echo "240.0.0.0"
			;;
		3)
			echo "224.0.0.0"
			;;
		2)
			echo "192.0.0.0"
			;;
		1)
			echo "128.0.0.0"
			;;
		0)
			echo "0.0.0.0"
			;;
		*)
			return ${EXIT_ERROR}
			;;
	esac

	return ${EXIT_OK}
}

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}"
}

ipv4_get_network() {
	ip_get_network "$@"
}

ipv4_get_broadcast() {
	inetcalc -4 -b "$@" && return ${EXIT_OK} || return ${EXIT_ERROR}
}

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

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

	print "${int}"
}

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}"
}

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

	local addr2=${2}
	assert isset addr2

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

ipv4_addr_gt() {
	assert [ $# -eq 2 ]

	local addr1="${1}"
	local addr2="${2}"

	inetcalc -4 -g "${addr1}" "${addr2}" \
		&& return ${EXIT_TRUE} || return ${EXIT_FALSE}
}

ipv4_addr_ge() {
	ipv4_addr_eq "$@" || ipv4_addr_gt "$@"
}

ipv4_addr_lt() {
	! ipv4_addr_eq "$@" && ! ipv4_addr_gt "$@"
}

ipv4_addr_le() {
	ipv4_addr_eq "$@" || ! ipv4_addr_gt "$@"
}

ipv4_range() {
	local range=${1}

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

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

_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
}

ipv4_range_explicit() {
	local range=${1}

	local first last

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

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

_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
}

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}
}

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}
}