src/etc/netstart

#!/bin/sh -
#
#	$OpenBSD: netstart,v 1.234 2022/12/18 15:52:52 kn Exp $

# Turn off Strict Bourne shell mode.
set +o sh

# Show usage of the netstart script and exit.
usage() {
	print -u2 "usage: sh $0 [-n] [interface ...]"
	exit 1
}

# Test the first argument against the remaining ones, return success on a match.
isin() {
	local _a=$1 _b

	shift
	for _b; do
		[[ $_a == "$_b" ]] && return 0
	done
	return 1
}

# Echo file $1 to stdout. Skip comment lines. Strip leading and trailing
# whitespace if IFS is set.
# Usage: stripcom /path/to/file
stripcom() {
	local _file=$1 _line

	[[ -f $_file ]] || return

	while read _line; do
		[[ -n ${_line%%#*} ]] && print -r -- "$_line"
	done <$_file
}

# Parse and "unpack" a hostname.if(5) line given as positional parameters.
# Fill the _cmds array with the resulting interface configuration commands.
parse_hn_line() {
	local _af=0 _name=1 _mask=2 _bc=3 _prefix=2 _c _cmd _prev _daddr _dhcp _i
	set -A _c -- "$@"
	set -o noglob

	case ${_c[_af]} in
	''|*([[:blank:]])'#'*)
		return
		;;
	inet)	((${#_c[*]} > 1)) || return
		if [[ ${_c[_name]} == autoconf ]]; then
			_cmds[${#_cmds[*]}]="ifconfig $_if ${_c[@]}"
			V4_AUTOCONF=true
			return
		fi
		[[ ${_c[_name]} == alias ]] && _mask=3 _bc=4
		[[ -n ${_c[_mask]} ]] && _c[_mask]="netmask ${_c[_mask]}"
		if [[ -n ${_c[_bc]} ]]; then
			_c[_bc]="broadcast ${_c[_bc]}"
			[[ ${_c[_bc]} == *NONE ]] && _c[_bc]=
		fi
		_cmds[${#_cmds[*]}]="ifconfig $_if ${_c[@]}"
		;;
	inet6)	((${#_c[*]} > 1)) || return
		if [[ ${_c[_name]} == autoconf ]]; then
			_cmds[${#_cmds[*]}]="ifconfig $_if ${_c[@]}"
			V6_AUTOCONF=true
			return
		fi
		[[ ${_c[_name]} == alias ]] && _prefix=3
		[[ -n ${_c[_prefix]} ]] && _c[_prefix]="prefixlen ${_c[_prefix]}"
		_cmds[${#_cmds[*]}]="ifconfig $_if ${_c[@]}"
		;;
	dest)	((${#_c[*]} == 2)) && _daddr=${_c[1]} || return
		_prev=$((${#_cmds[*]} - 1))
		((_prev >= 0)) || return
		set -A _c -- ${_cmds[_prev]}
		_name=3
		[[ ${_c[_name]} == alias ]] && _name=4
		_c[_name]="${_c[_name]} $_daddr"
		_cmds[$_prev]="${_c[@]}"
		;;
	dhcp)	_cmds[${#_cmds[*]}]="ifconfig $_if inet autoconf"
		V4_AUTOCONF=true
		;;
	'!'*)	_cmd=$(print -- "${_c[@]}" | sed 's/\$if/'$_if'/g')
		_cmds[${#_cmds[*]}]="${_cmd#!}"
		;;
	*)	_cmds[${#_cmds[*]}]="ifconfig $_if ${_c[@]}"
		;;
	esac
	unset _c
	set +o noglob
}

# Create interface $1 if it does not yet exist.
# Usage: ifcreate if1
ifcreate() {
	local _if=$1

	if $PRINT_ONLY; then
		print -r -- "{ ifconfig $_if || ifconfig $_if create; }"
	else
		{ ifconfig $_if || ifconfig $_if create; } >/dev/null 2>&1
	fi
}

# Create interfaces for network pseudo-devices referred to by hostname.if files.
# Optionally, limit creation to given interfaces only.
# Usage: vifscreate [if ...]
vifscreate() {
	local _vif _hn _if

	for _vif in $(ifconfig -C); do
		for _hn in /etc/hostname.${_vif}+([[:digit:]]); do
			[[ -f $_hn ]] || continue
			_if=${_hn#/etc/hostname.}

			# loopback for routing domain is created by kernel
			[[ -n ${_if##lo[1-9]*} ]] || continue

			if (($# > 0)) && ! isin $_if "$@"; then
				continue
			fi

			if ! ifcreate $_if; then
				print -u2 "${0##*/}: create for '$_if' failed."
			fi
		done
	done
}

# Start a single interface.
# Usage: ifstart if1
ifstart() {
	local _if=$1 _lladdr _hn=/etc/hostname.$1 _cmds _i=0 _line _stat
	set -A _cmds

	# Interface names must be alphanumeric only.  We check to avoid
	# configuring backup or temp files, and to catch the "*" case.
	if [[ $_if == +([[:alpha:]])+([[:digit:]]) ]]; then
		_lladdr=$(ifconfig $_if 2>/dev/null |
		    sed -n 's/^[[:space:]]*lladdr[[:space:]]//p')
		if [[ -n $_lladdr && -f /etc/hostname.$_lladdr &&
		    -n $(ifconfig -M "$_lladdr") ]]; then
			print -u2 "${0##*/}: $_hn: /etc/hostname.$_lladdr overrides"
			return
		fi

	# We also support hostname.lladdr, but it must resolve to be valid
	elif [[ $_if == ??:??:??:??:??:?? ]]; then
		_lladdr=$_if
		_if=$(ifconfig -M $_lladdr)
		if (($? != 0)); then
			print -u2 "${0##*/}: $_lladdr is not unique."
			return
		fi

		[[ -z $_if ]] && return
	else
		return
	fi

	if [[ ! -f $_hn ]]; then
		print -u2 "${0##*/}: $_hn: No such file or directory."
		return
	fi

	# Not using stat(1), we can't rely on having /usr yet.
	set -A _stat -- $(ls -nL $_hn)
	if [[ "${_stat[0]}${_stat[2]}${_stat[3]}" != *---00 ]]; then
		print -u2 "WARNING: $_hn is insecure, fixing permissions."
		chmod -LR o-rwx $_hn
		chown -LR root:wheel $_hn
	fi

	# Check for ifconfig'able interface, except if -n option is specified.
	ifcreate $_if || return

	# Parse the hostname.if(5) file and fill _cmds array with interface
	# configuration commands.
	set -o noglob
	while IFS= read -- _line; do
		parse_hn_line $_line
	done <$_hn

	# Apply the interface configuration commands stored in _cmds array.
	while ((_i < ${#_cmds[*]})); do
		if $PRINT_ONLY; then
			print -r -- "${_cmds[_i]}"
		else
			eval "${_cmds[_i]}"
		fi
		((_i++))
	done
	unset _cmds
	set +o noglob
}

# Start multiple interfaces by driver name.
# Usage: ifmstart "em iwm" "trunk vlan"
#   Start "$1" interfaces in order or all interfaces if empty.
#   Don't start "$2" interfaces. "$2" is optional.
ifmstart() {
	local _sifs=$1 _xifs=$2 _hn _if _sif _xif

	for _sif in ${_sifs:-ALL}; do
		for _hn in /etc/hostname.@(+([[:alpha:]])+([[:digit:]])|??:??:??:??:??:??); do
			[[ -f $_hn ]] || continue
			_if=${_hn#/etc/hostname.}

			if [[ $_if == +([[:alpha:]])+([[:digit:]]) ]]; then
				# Skip unwanted ifs.
				for _xif in $_xifs; do
					[[ $_xif == ${_if%%[0-9]*} ]] && continue 2
				done
			fi

			# Start wanted ifs.
			[[ $_sif == @(ALL|${_if%%[0-9]*}) ]] && ifstart $_if
		done
	done
}

# Parse /etc/mygate and add default routes for IPv4 and IPv6.
# Usage: defaultroute
defaultroute() {
	local _cmd _v4set=false _v6set=false;
	set -o noglob

	stripcom /etc/mygate |
	while read gw; do
		case $gw in
		'!'*)
			_cmd=$(print -- "$gw")
			_cmd="${_cmd#!}"
			;;
		!(*:*))
			($_v4set || $V4_AUTOCONF) && continue
			_cmd="route -qn add -host default $gw"
			_v4set=true
			;;
		*)
			($_v6set || $V6_AUTOCONF) && continue
			_cmd="route -qn add -host -inet6 default $gw"
			_v6set=true
			;;
		esac
		if $PRINT_ONLY; then
			print -r -- "$_cmd"
		else
			$_cmd
		fi
	done
	set +o noglob
}

# add all the routes needed for IPv6
ip6routes() {
	local _i=0
	set -A _cmds

	# Disallow link-local unicast dest without outgoing scope identifiers.
	_cmds[_i++]="route -qn add -inet6 fe80:: -prefixlen 10 ::1 -reject"

	# Disallow site-local unicast dest without outgoing scope identifiers.
	# If you configure site-locals without scope id (it is permissible
	# config for routers that are not on scope boundary), you may want
	# to comment the line out.
	_cmds[_i++]="route -qn add -inet6 fec0:: -prefixlen 10 ::1 -reject"

	# Disallow "internal" addresses to appear on the wire.
	_cmds[_i++]="route -qn add -inet6 ::ffff:0.0.0.0 -prefixlen 96 ::1 -reject"

	# Disallow packets to malicious 6to4 prefix.
	_cmds[_i++]="route -qn add -inet6 2002:e000:: -prefixlen 20 ::1 -reject"
	_cmds[_i++]="route -qn add -inet6 2002:7f00:: -prefixlen 24 ::1 -reject"
	_cmds[_i++]="route -qn add -inet6 2002:0000:: -prefixlen 24 ::1 -reject"
	_cmds[_i++]="route -qn add -inet6 2002:ff00:: -prefixlen 24 ::1 -reject"

	# Disallow packets without scope identifier.
	_cmds[_i++]="route -qn add -inet6 ff01:: -prefixlen 16 ::1 -reject"
	_cmds[_i++]="route -qn add -inet6 ff02:: -prefixlen 16 ::1 -reject"

	# Completely disallow packets to IPv4 compatible prefix.
	#
	# This may conflict with RFC1933 under following circumstances:
	# (1) An IPv6-only KAME node tries to originate packets to IPv4
	#     compatible destination.  The KAME node has no IPv4 compatible
	#     support.  Under RFC1933, it should transmit native IPv6
	#     packets toward IPv4 compatible destination, hoping it would
	#     reach a router that forwards the packet toward auto-tunnel
	#     interface.
	# (2) An IPv6-only node originates a packet to an IPv4 compatible
	#     destination.  A KAME node is acting as an IPv6 router, and
	#     asked to forward it.
	#
	# Due to rare use of IPv4 compatible addresses, and security issues
	# with it, we disable it by default.
	_cmds[_i++]="route -qn add -inet6 ::0.0.0.0 -prefixlen 96 ::1 -reject"

	# Apply the interface configuration commands stored in _cmds array.
	_i=0
	while ((_i < ${#_cmds[*]})); do
		if $PRINT_ONLY; then
			print -r -- "${_cmds[_i]}"
		else
			eval "${_cmds[_i]}"
		fi
		((_i++))
	done
	unset _cmds
}

# wait for autoconf interfaces
wait_autoconf_default() {
	local _count=0

	if ifconfig | grep -q ': flags=.*<.*AUTOCONF.*>'; then
		while ((_count++ < 20)); do
			route -n show | grep -q ^default && break
			sleep .5
		done
	fi
}

# Ensure IPv6 Duplicate Address Detection (DAD) is completed.
wait_dad() {
	local _count=0

	while ((_count++ < 10 && $(sysctl -n net.inet6.ip6.dad_pending) != 0)); do
		sleep 1
	done
}

# Make sure the invoking user has the right privileges.  Check for presence of
# id(1) to avoid problems with diskless setups.
if [[ -x /usr/bin/id ]] && (($(id -u) != 0)); then
	print -u2 "${0##*/}: need root privileges"
	exit 1
fi

# Get network related vars from rc.conf using the parsing routine from rc.subr.
FUNCS_ONLY=1 . /etc/rc.d/rc.subr
_rc_parse_conf

PRINT_ONLY=false
V4_AUTOCONF=false
V6_AUTOCONF=false
IP6KERNEL=false

while getopts ":n" opt; do
	case $opt in
	n)	PRINT_ONLY=true;;
	*)	usage;;
	esac
done
shift $((OPTIND-1))

if ifconfig lo0 inet6 >/dev/null 2>&1; then
	IP6KERNEL=true
fi

# Load key material for the generation of IPv6 Semantically Opaque Interface
# Identifiers (SOII) used for SLAAC addresses.
if $IP6KERNEL && ! $PRINT_ONLY; then
	[[ -f /etc/soii.key ]] &&
		sysctl -q "net.inet6.ip6.soiikey=$(</etc/soii.key)"
fi

# If we were invoked with a list of interface names, just reconfigure these
# interfaces (or bridges), add default routes and return.
# Create virtual interfaces upfront to make ifconfig commands depending on
# other interfaces, e.g. "patch", work regardless of in which order interface
# names were specified.
if (($# > 0)); then
	vifscreate "$@"
	for _if; do ifstart $_if; done
	defaultroute
	return
fi

# Otherwise, process with the complete network initialization.

# Set the address for the loopback interface.  Bringing the interface up,
# automatically invokes the IPv6 address ::1.
if $PRINT_ONLY; then
	print -r -- "ifconfig lo0 inet 127.0.0.1/8"
else
	ifconfig lo0 inet 127.0.0.1/8
fi

if $IP6KERNEL && ! $PRINT_ONLY; then
	ip6routes
fi

# Create all the pseudo interfaces up front.
vifscreate

# Configure all the non-loopback interfaces which we know about, but
# do not start interfaces which must be delayed. Refer to hostname.if(5)
ifmstart "" "aggr trunk svlan vlan carp pppoe tun tap gif etherip gre egre nvgre eoip vxlan pflow wg"

# The aggr and trunk interfaces need to come up first in this list.
# The (s)vlan interfaces need to come up after trunk.
# Configure all the carp interfaces which we know about before default route.
ifmstart "aggr trunk svlan vlan carp pppoe"

# Set default routes for IPv4 and IPv6.
defaultroute

# Multicast routing.
if [[ $multicast != YES ]]; then
	if $PRINT_ONLY; then
		print -r -- "route -qn delete 224.0.0.0/4"
		print -r -- "route -qn add -net 224.0.0.0/4 -interface 127.0.0.1 -reject"
	else
		route -qn delete 224.0.0.0/4
		route -qn add -net 224.0.0.0/4 -interface 127.0.0.1 -reject
	fi
fi

# Reject 127/8 other than 127.0.0.1.
if $PRINT_ONLY; then
	print -r -- "route -qn add -net 127 127.0.0.1 -reject"
else
	route -qn add -net 127 127.0.0.1 -reject
fi

# If interface autoconf exists, pause a little for at least one default route
$PRINT_ONLY || wait_autoconf_default

# Configure interfaces that rely on routing
ifmstart "tun tap gif etherip gre egre nvgre eoip vxlan pflow wg"

if $IP6KERNEL && ! $PRINT_ONLY; then
	wait_dad
fi