#!/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} ipv6"

function ipv6_device_autoconf_enable() {
	local device="${1}"
	assert device_exists "${device}"

	sysctl_set "net.ipv6.conf.${device}.accept_ra" 1
	sysctl_set "net.ipv6.conf.${device}.autoconf" 1
}

function ipv6_device_autoconf_disable() {
	local device="${1}"
	assert device_exists "${device}"

	sysctl_set "net.ipv6.conf.${device}.accept_ra" 0
	sysctl_set "net.ipv6.conf.${device}.autoconf" 0
}

# Enable IPv6 RFC3041 privacy extensions if desired
function ipv6_device_privacy_extensions_enable() {
	local device="${1}"
	assert device_exists "${device}"

	sysctl_set "net.ipv6.conf.${device}.use_tempaddr" 2
}

function ipv6_device_privacy_extensions_disable() {
	local device="${1}"
	assert device_exists "${device}"

	sysctl_set "net.ipv6.conf.${device}.use_tempaddr" 0
}

function ipv6_is_valid() {
	ipcalc --ipv6 -c $@ >/dev/null 2>&1

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

function ipv6_prefix_is_valid() {
	local prefix=${1}
	assert isset prefix

	[ ${prefix} -le   0 ] && return ${EXIT_FALSE}
	[ ${prefix} -gt 128 ] && return ${EXIT_FALSE}

	return ${EXIT_TRUE}
}

function ipv6_get_prefix() {
	ip_get_prefix "$@"
}

function ipv6_split_prefix() {
	ip_split_prefix "$@"
}

function ipv6_implode() {
	local address=${1}
	assert isset address

	local ADDRESS6_IMPL
	eval $(ipcalc -6 -i ${address} 2>/dev/null)
	assert isset ADDRESS6_IMPL

	print "${ADDRESS6_IMPL}"
}

function ipv6_explode() {
	local address=${1}
	assert isset address

	# Nothing to do if the length of the address is 39.
	if [ ${#address} -eq 39 ]; then
		print "${address}"
		return ${EXIT_OK}
	fi

	local ADDRESS6_EXPL
	eval $(ipcalc -6 -e ${address} 2>/dev/null)
	assert isset ADDRESS6_EXPL

	print "${ADDRESS6_EXPL}"
}

function ipv6_addr_eq() {
	local addr1=${1}
	assert isset addr1

	local addr2=${2}
	assert isset addr2

	local addr
	for addr in addr1 addr2; do
		printf -v ${addr} "%s" $(ipv6_explode ${!addr})
	done

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

function ipv6_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" $(ipv6_explode ${!addr})
	done

	local i addr1_oct addr2_oct
	for i in 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30; do
		addr1_oct="0x${addr1:${i}:2}"
		addr2_oct="0x${addr2:${i}:2}"

		[[ ${addr1_oct} -gt ${addr2_oct} ]] && return ${EXIT_TRUE}
	done

	return ${EXIT_FALSE}
}

function ipv6_hash() {
	local address=${1}

	assert isset address

	# Explode address
	address=$(ipv6_explode ${address})

	echo "${address//:/}"
}

function ipv6_get_network() {
	local addr=${1}
	assert isset addr

	# Check if a prefix (e.g. /64) is provided.
	local prefix=$(ip_get_prefix ${addr})
	assert ipv6_prefix_is_valid ${prefix}

	local PREFIX6
	eval $(ipcalc --ipv6 -p ${addr})
	assert isset PREFIX6

	print "${PREFIX6}/${prefix}"
}

function ipv6_6rd_format_address() {
	local isp_prefix="${1}"
	assert ipv6_is_valid "${isp_prefix}"

	local client_address="${2}"
	assert ipv4_is_valid "${client_address}"

	local prefix="$(ipv6_get_prefix "${isp_prefix}")"
	isp_prefix="$(ipv6_split_prefix "${isp_prefix}")"

	# This only works for prefix lengths up to 32 bit.
	assert [ "${prefix}" -le 32 ]
	assert [ "${prefix}" -gt  0 ]

	# Explode the address and throw away the second 32 bit.
	local address="$(ipv6_explode "${isp_prefix}")"

	client_address="$(ipv6_6rd_format_client_address ${client_address})"
	assert isset client_address

	local block1="0x${address:0:4}"
	local block2="0x${address:5:4}"
	local block3="0x${address:10:4}"
	local block4="0x${address:15:4}"

	address="$(( (${block1} << 48) + (${block2} << 32) + (${block3} << 16) + ${block4} ))"
	assert [ "${address}" -gt 0 ]

	block1="0x${client_address:0:4}"
	block2="0x${client_address:5:4}"

	client_address="$(( (${block1} << 48) + (${block2} << 32) ))"

	# Fix for numbers that are interpreted by bash as negative
	# numbers and therefore filled up with ones when shifted to
	# the right. Weird.
	if [ "${client_address}" -gt 0 ]; then
		client_address="$(( ${client_address} >> ${prefix} ))"
	else
		local bitmask="$(( 1 << 63 ))"
		client_address="$(( ${client_address} >> 1 ))"
		client_address="$(( ${client_address} ^ ${bitmask} ))"
		client_address="$(( ${client_address} >> $(( ${prefix} - 1 )) ))"
	fi
	assert [ "${client_address}" -gt 0 ]

	# XOR everything together
	address="$(( ${address} ^ ${client_address} ))"
	prefix="$(( ${prefix} + 32 ))"

	local block formatted_address=":"
	while [ ${address} -gt 0 ]; do
		printf -v block "%x" "$(( ${address} & 0xffff ))"
		formatted_address="${block}:${formatted_address}"

		address="$(( ${address} >> 16 ))"
	done

	assert ipv6_is_valid "${formatted_address}"

	# Implode the output IP address.
	formatted_address="$(ipv6_implode "${formatted_address}")"

	print "${formatted_address}/${prefix}"
}

function ipv6_6rd_format_client_address() {
	local address="${1}"
	assert isset address

	print "%02x%02x:%02x%02x" ${address//\./ }
}