HardenedBSD/etc/network.subr

#
# Copyright (c) 2003 The FreeBSD Project. All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.
#
# $FreeBSD$
#

#
# Subroutines commonly used from network startup scripts.
# Requires that rc.conf be loaded first.
#

# ifconfig_up if
#	Evaluate ifconfig(8) arguments for interface $if and
#	run ifconfig(8) with those arguments. It returns 0 if
#	arguments were found and executed or 1 if the interface
#	had no arguments.  Pseudo arguments DHCP and WPA are handled
#	here.
#
ifconfig_up()
{
	_cfg=1

	ifconfig_args=`ifconfig_getargs $1`
	if [ -n "${ifconfig_args}" ]; then
		ifconfig $1 up
		eval "ifconfig $1 ${ifconfig_args}"
		_cfg=0
	fi

	if wpaif $1; then
		if [ $_cfg -ne 0 ] ; then
			ifconfig $1 up
		fi
		/etc/rc.d/wpa_supplicant start $1
		_cfg=0		# XXX: not sure this should count
	fi

	if dhcpif $1; then
		if [ $_cfg -ne 0 ] ; then
			ifconfig $1 up
		fi
		/etc/rc.d/dhclient start $1
		_cfg=0
	fi

	return $_cfg
}

# ifconfig_down if
#	Remove all inet entries from the $if interface. It returns
#	0 if inet entries were found and removed. It returns 1 if
#	no entries were found or they could not be removed.
#
ifconfig_down()
{
	[ -z "$1" ] && return 1
	_ifs="^"
	_cfg=1

	inetList="`ifconfig $1 | grep 'inet ' | tr "\n" "$_ifs"`"

	oldifs="$IFS"
	IFS="$_ifs"
	for _inet in $inetList ; do
		# get rid of extraneous line
		[ -z "$_inet" ] && break

		_inet=`expr "$_inet" : '.*\(inet \([0-9]\{1,3\}\.\)\{3\}[0-9]\{1,3\}\).*'`

		IFS="$oldifs"
		ifconfig $1 ${_inet} delete
		IFS="$_ifs"
		_cfg=0
	done
	IFS="$oldifs"

	if wpaif $1; then
		/etc/rc.d/wpa_supplicant stop $1
		_cfg=0
	fi

	if dhcpif $1; then
		/etc/rc.d/dhclient stop $1
		_cfg=0
	fi

	return $_cfg
}

# _ifconfig_getargs if
#	Echos the arguments for the supplied interface to stdout.
#	returns 1 if empty.  In general, ifconfig_getargs should be used
#	outside this file.
_ifconfig_getargs()
{
	_ifn=$1
	if [ -z "$_ifn" ]; then
		return 1
	fi

	eval _args=\${ifconfig_$1-$ifconfig_DEFAULT}

	echo "$_args"
}

# ifconfig_getargs if
#	Takes the result from _ifconfig_getargs and removes pseudo
#	args such as DHCP and WPA.
ifconfig_getargs()
{
	_tmpargs=`_ifconfig_getargs $1`
	if [ $? -eq 1 ]; then
		return 1
	fi
	_args=

	for _arg in $_tmpargs; do
		case $_arg in
		[Dd][Hh][Cc][Pp])
			;;
		[Nn][Oo][Aa][Uu][Tt][Oo])
			;;
		[Ww][Pp][Aa])
			;;
		*)
			_args="$_args $_arg"
			;;
		esac
	done

	echo $_args
}

# autoif
#	Returns 0 if the interface should be automaticly configured at
#	boot time and 1 otherwise.
autoif()
{
	_tmpargs=`_ifconfig_getargs $1`
	for _arg in $_tmpargs; do
		case $_arg in
		[Nn][Oo][Aa][Uu][Tt][Oo])
			return 1
			;;
		esac
	done
	return 0
}

# dhcpif if
#	Returns 0 if the interface is a DHCP interface and 1 otherwise.
dhcpif()
{
	_tmpargs=`_ifconfig_getargs $1`
	for _arg in $_tmpargs; do
		case $_arg in
		[Dd][Hh][Cc][Pp])
			return 0
			;;
		esac
	done
	return 1
}

# wpaif if
#	Returns 0 if the interface is a WPA interface and 1 otherwise.
wpaif()
{
	_tmpargs=`_ifconfig_getargs $1`
	for _arg in $_tmpargs; do
		case $_arg in
		[Ww][Pp][Aa])
			return 0
			;;
		esac
	done
	return 1
}

# ifalias_up if
#	Configure aliases for network interface $if.
#	It returns 0 if at least one alias was configured or
#	1 if there were none.
#
ifalias_up()
{
	_ret=1
	alias=0
	while : ; do
		eval ifconfig_args=\$ifconfig_$1_alias${alias}
		if [ -n "${ifconfig_args}" ]; then
			ifconfig $1 ${ifconfig_args} alias
			alias=$((${alias} + 1))
			_ret=0
		else
			break
		fi
	done
	return $_ret
}

#ifalias_down if
#	Remove aliases for network interface $if.
#	It returns 0 if at least one alias was removed or
#	1 if there were none.
#
ifalias_down()
{
	_ret=1
	alias=0
	while : ; do
		eval ifconfig_args=\$ifconfig_$1_alias${alias}
		if [ -n "${ifconfig_args}" ]; then
			ifconfig $1 ${ifconfig_args} -alias
			alias=$((${alias} + 1))
			_ret=0
		else
			break
		fi
	done
	return $_ret
}

# ifscript_up if
#	Evaluate a startup script for the $if interface.
#	It returns 0 if a script was found and processed or
#	1 if no script was found.
#
ifscript_up()
{
	if [ -r /etc/start_if.$1 ]; then
		. /etc/start_if.$1
		return 0
	fi
	return 1
}

# ifscript_down if
#	Evaluate a shutdown script for the $if interface.
#	It returns 0 if a script was found and processed or
#	1 if no script was found.
#
ifscript_down()
{
	if [ -r /etc/stop_if.$1 ]; then
		. /etc/stop_if.$1
		return 0
	fi
	return 1
}

# Create cloneable interfaces.
#
clone_up()
{
	_prefix=
	_list=
	for ifn in ${cloned_interfaces}; do
		ifconfig ${ifn} create
		if [ $? -eq 0 ]; then
			_list="${_list}${_prefix}${ifn}"
			[ -z "$_prefix" ] && _prefix=' '
		fi
	done
	debug "Cloned: ${_list}"
}

# Destroy cloned interfaces. Destroyed interfaces are echoed
# to standard output.
#
clone_down()
{
	_prefix=
	_list=
	for ifn in ${cloned_interfaces}; do
		ifconfig ${ifn} destroy
		if [ $? -eq 0 ]; then
			_list="${_list}${_prefix}${ifn}"
			[ -z "$_prefix" ] && _prefix=' '
		fi
	done
	debug "Destroyed clones: ${_list}"
}

gif_up() {
	case ${gif_interfaces} in
	[Nn][Oo] | '')
		;;
	*)
		for i in ${gif_interfaces}; do
			eval peers=\$gifconfig_$i
			case ${peers} in
			'')
				continue
				;;
			*)
				ifconfig $i create >/dev/null 2>&1
				ifconfig $i tunnel ${peers}
				ifconfig $i up
				;;
			esac
		done
		;;
	esac
}

#
# ipx_up ifn
# Configure any IPX addresses for interface $ifn. Returns 0 if IPX
# arguments were found and configured; returns 1 otherwise.
#
ipx_up()
{
	ifn="$1"
	eval ifconfig_args=\$ifconfig_${ifn}_ipx
	if [ -n "${ifconfig_args}" ]; then
		ifconfig ${ifn} ${ifconfig_args}
		return 0
	fi
	return 1
}

# ipx_down ifn
#	Remove IPX addresses for interface $ifn. Returns 0 if IPX
#	addresses were found and unconfigured. It returns 1, otherwise.
#
ipx_down()
{
	[ -z "$1" ] && return 1
	_ifs="^"
	_ret=1

	ipxList="`ifconfig $1 | grep 'ipx ' | tr "\n" "$_ifs"`"

	oldifs="$IFS"
	IFS="$_ifs"
	for _ipx in $ipxList ; do
		# get rid of extraneous line
		[ -z "$_ipx" ] && break

		_ipx=`expr "$_ipx" : '.*\(ipx [0-9a-h]\{1,8\}H*\.[0-9a-h]\{1,12\}\).*'`

		IFS="$oldifs"
		ifconfig $1 ${_ipx} delete
		IFS="$_ifs"
		_ret=0
	done
	IFS="$oldifs"

	return $_ret
}

# ifnet_rename
#	Rename all requested interfaces.
#
ifnet_rename()
{

	_ifn_list="`ifconfig -l`"
	[ -z "$_ifn_list" ] && return 0
	for _if in ${_ifn_list} ; do
		eval _ifname=\$ifconfig_${_if}_name
		if [ ! -z "$_ifname" ]; then
			ifconfig $_if name $_ifname
		fi
	done
	return 0
}

#
# list_net_interfaces type
#	List all network interfaces. The type of interface returned
#	can be controlled by the type argument. The type
#	argument can be any of the following:
#		nodhcp - all interfaces, excluding DHCP configured interfaces
#		dhcp   - list only DHCP configured interfaces
#	If no argument is specified all network interfaces are output.
#	Note that the list will include cloned interfaces if applicable.
#	Cloned interfaces must already exist to have a chance to appear
#	in the list if ${network_interfaces} is set to `auto'.
#
list_net_interfaces()
{
	type=$1

	# Get a list of ALL the interfaces and make lo0 first if it's there.
	#
	case ${network_interfaces} in
	[Aa][Uu][Tt][Oo])
		_prefix=''
		_autolist="`ifconfig -l`"
		_lo=
		for _if in ${_autolist} ; do
			if autoif $_if; then
				if [ "$_if" = "lo0" ]; then
					_lo="lo0 "
				else
					_tmplist="${_tmplist}${_prefix}${_if}"
					[ -z "$_prefix" ] && _prefix=' '
				fi
			fi
		done
		_tmplist="${_lo}${_tmplist}"
		;;
	*)
		_tmplist="${network_interfaces} ${cloned_interfaces}"
		;;
	esac

	if [ -z "$type" ]; then
		echo $_tmplist
		return 0
	fi

	# Separate out dhcp and non-dhcp interfaces
	#
	_aprefix=
	_bprefix=
	for _if in ${_tmplist} ; do
		if dhcpif $_if; then
			_dhcplist="${_dhcplist}${_aprefix}${_if}"
			[ -z "$_aprefix" ] && _aprefix=' '
		elif [ -n "`_ifconfig_getargs $if`" ]; then
			_nodhcplist="${_nodhcplist}${_bprefix}${_if}"
			[ -z "$_bprefix" ] && _bprefix=' '
		fi
	done

	case "$type" in
	nodhcp)
		echo $_nodhcplist
		;;
	dhcp)
		echo $_dhcplist
		;;
	esac
	return 0
}

hexdigit()
{
	if [ $1 -lt 10 ]; then
		echo $1
	else
		case $1 in
		10)	echo a ;;
		11)	echo b ;;
		12)	echo c ;;
		13)	echo d ;;
		14)	echo e ;;
		15)	echo f ;;
		esac
	fi
}

hexprint()
{
	val=$1
	str=''

	dig=`hexdigit $((${val} & 15))`
	str=${dig}${str}
	val=$((${val} >> 4))
	while [ ${val} -gt 0 ]; do
		dig=`hexdigit $((${val} & 15))`
		str=${dig}${str}
		val=$((${val} >> 4))
	done

	echo ${str}
}

# Setup the interfaces for IPv6
network6_interface_setup()
{
	interfaces=$*
	rtsol_interfaces=''
	case ${ipv6_gateway_enable} in
	[Yy][Ee][Ss])
		rtsol_available=no
		;;
	*)
		rtsol_available=yes
		;;
	esac
	for i in $interfaces; do
		rtsol_interface=yes
		eval prefix=\$ipv6_prefix_$i
		if [ -n "${prefix}" ]; then
			rtsol_available=no
			rtsol_interface=no
			laddr=`network6_getladdr $i`
			hostid=`expr "${laddr}" : 'fe80::\(.*\)%\(.*\)'`
			for j in ${prefix}; do
				address=$j\:${hostid}
				ifconfig $i inet6 ${address} prefixlen 64 alias

				case ${ipv6_gateway_enable} in
				[Yy][Ee][Ss])
					# subnet-router anycast address
					# (rfc2373)
					ifconfig $i inet6 $j:: prefixlen 64 \
						alias anycast
					;;
				esac
			done
		fi
		eval ipv6_ifconfig=\$ipv6_ifconfig_$i
		if [ -n "${ipv6_ifconfig}" ]; then
			rtsol_available=no
			rtsol_interface=no
			ifconfig $i inet6 ${ipv6_ifconfig} alias
		fi

		if [ ${rtsol_available} = yes -a ${rtsol_interface} = yes ]
		then
			case ${i} in
			lo0|gif[0-9]*|stf[0-9]*|faith[0-9]*|lp[0-9]*|sl[0-9]*|tun[0-9]*)
				;;
			*)
				rtsol_interfaces="${rtsol_interfaces} ${i}"
				;;
			esac
		else
			ifconfig $i inet6
		fi
	done

	if [ ${rtsol_available} = yes -a -n "${rtsol_interfaces}" ]; then
		# Act as endhost - automatically configured.
		# You can configure only single interface, as
		# specification assumes that autoconfigured host has
		# single interface only.
		sysctl net.inet6.ip6.accept_rtadv=1
		set ${rtsol_interfaces}
		ifconfig $1 up
		rtsol ${rtsol_flags} $1
	fi

	for i in $interfaces; do
		alias=0
		while : ; do
			eval ipv6_ifconfig=\$ipv6_ifconfig_${i}_alias${alias}
			if [ -z "${ipv6_ifconfig}" ]; then
				break;
			fi
			ifconfig $i inet6 ${ipv6_ifconfig} alias
			alias=$((${alias} + 1))
		done
	done
}

# Setup IPv6 to IPv4 mapping
network6_stf_setup()
{
	case ${stf_interface_ipv4addr} in
	[Nn][Oo] | '')
		;;
	*)
		# assign IPv6 addr and interface route for 6to4 interface
		stf_prefixlen=$((16+${stf_interface_ipv4plen:-0}))
		OIFS="$IFS"
		IFS=".$IFS"
		set ${stf_interface_ipv4addr}
		IFS="$OIFS"
		hexfrag1=`hexprint $(($1*256 + $2))`
		hexfrag2=`hexprint $(($3*256 + $4))`
		ipv4_in_hexformat="${hexfrag1}:${hexfrag2}"
		case ${stf_interface_ipv6_ifid} in
		[Aa][Uu][Tt][Oo] | '')
			for i in ${ipv6_network_interfaces}; do
				laddr=`network6_getladdr ${i}`
				case ${laddr} in
				'')
					;;
				*)
					break
					;;
				esac
			done
			stf_interface_ipv6_ifid=`expr "${laddr}" : \
						      'fe80::\(.*\)%\(.*\)'`
			case ${stf_interface_ipv6_ifid} in
			'')
				stf_interface_ipv6_ifid=0:0:0:1
				;;
			esac
			;;
		esac
		ifconfig stf0 create >/dev/null 2>&1
		ifconfig stf0 inet6 2002:${ipv4_in_hexformat}:${stf_interface_ipv6_slaid:-0}:${stf_interface_ipv6_ifid} \
			prefixlen ${stf_prefixlen}
		# disallow packets to malicious 6to4 prefix
		route add -inet6 2002:e000:: -prefixlen 20 ::1 -reject
		route add -inet6 2002:7f00:: -prefixlen 24 ::1 -reject
		route add -inet6 2002:0000:: -prefixlen 24 ::1 -reject
		route add -inet6 2002:ff00:: -prefixlen 24 ::1 -reject
		;;
	esac
}

# Setup static routes
network6_static_routes_setup()
{
	# Set up any static routes.
	case ${ipv6_defaultrouter} in
	[Nn][Oo] | '')
		;;
	*)
		ipv6_static_routes="default ${ipv6_static_routes}"
		ipv6_route_default="default ${ipv6_defaultrouter}"
		;;
	esac
	case ${ipv6_static_routes} in
	[Nn][Oo] | '')
		;;
	*)
		for i in ${ipv6_static_routes}; do
			eval ipv6_route_args=\$ipv6_route_${i}
			route add -inet6 ${ipv6_route_args}
		done
		;;
	esac
}

# Setup faith
network6_faith_setup()
{
	case ${ipv6_faith_prefix} in
	[Nn][Oo] | '')
		;;
	*)
		sysctl net.inet6.ip6.keepfaith=1
		ifconfig faith0 create >/dev/null 2>&1
		ifconfig faith0 up
		for prefix in ${ipv6_faith_prefix}; do
			prefixlen=`expr "${prefix}" : ".*/\(.*\)"`
			case ${prefixlen} in
			'')
				prefixlen=96
				;;
			*)
				prefix=`expr "${prefix}" : \
					     "\(.*\)/${prefixlen}"`
				;;
			esac
			route add -inet6 ${prefix} -prefixlen ${prefixlen} ::1
			route change -inet6 ${prefix} -prefixlen ${prefixlen} \
				-ifp faith0
		done
		;;
	esac
}

# Install the "default interface" to kernel, which will be used
# as the default route when there's no router.
network6_default_interface_setup()
{
	# Choose IPv6 default interface if it is not clearly specified.
	case ${ipv6_default_interface} in
	'')
		for i in ${ipv6_network_interfaces}; do
			case $i in
			lo0|faith[0-9]*)
				continue
				;;
			esac
			laddr=`network6_getladdr $i exclude_tentative`
			case ${laddr} in
			'')
				;;
			*)
				ipv6_default_interface=$i
				break
				;;
			esac
		done
		;;
	esac

	# Disallow unicast packets without outgoing scope identifiers,
	# or route such packets to a "default" interface, if it is specified.
	route add -inet6 fe80:: -prefixlen 10 ::1 -reject
	case ${ipv6_default_interface} in
	[Nn][Oo] | '')
		route add -inet6 ff02:: -prefixlen 16 ::1 -reject
		;;
	*)
		laddr=`network6_getladdr ${ipv6_default_interface}`
		route add -inet6 ff02:: ${laddr} -prefixlen 16 -interface \
			-cloning

		# Disable installing the default interface with the
		# case net.inet6.ip6.forwarding=0 and
		# net.inet6.ip6.accept_rtadv=0, due to avoid conflict
		# between the default router list and the manual
		# configured default route.
		case ${ipv6_gateway_enable} in
		[Yy][Ee][Ss])
			;;
		*)
			if [ `sysctl -n net.inet6.ip6.accept_rtadv` -eq 1 ]
			then
				ndp -I ${ipv6_default_interface}
			fi
			;;
		esac
		;;
	esac
}

network6_getladdr()
{
	ifconfig $1 2>/dev/null | while read proto addr rest; do
		case ${proto} in
		inet6)
			case ${addr} in
			fe80::*)
				if [ -z "$2" ]; then
					echo ${addr}
					return
				fi
				case ${rest} in
				*tentative*)
					continue
					;;
				*)
					echo ${addr}
					return
				esac
			esac
		esac
	done
}