From 6b7f88aa7d7545bddac91e33698034959abb13d4 Mon Sep 17 00:00:00 2001
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: Tue, 22 May 2018 16:32:01 +0200
Subject: [PATCH] wg-quick: openbsd: add new implementation

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 src/wg-quick/openbsd.bash | 451 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 451 insertions(+)
 create mode 100755 src/wg-quick/openbsd.bash

diff --git a/src/wg-quick/openbsd.bash b/src/wg-quick/openbsd.bash
new file mode 100755
index 0000000..b8934d4
--- /dev/null
+++ b/src/wg-quick/openbsd.bash
@@ -0,0 +1,451 @@
+#!/usr/local/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Copyright (C) 2015-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+#
+
+set -e -o pipefail
+shopt -s extglob
+export LC_ALL=C
+
+SELF="$(readlink -f "${BASH_SOURCE[0]}")"
+export PATH="${SELF%/*}:$PATH"
+
+WG_CONFIG=""
+INTERFACE=""
+ADDRESSES=( )
+MTU=""
+DNS=( )
+TABLE=""
+PRE_UP=( )
+POST_UP=( )
+PRE_DOWN=( )
+POST_DOWN=( )
+SAVE_CONFIG=0
+CONFIG_FILE=""
+PROGRAM="${0##*/}"
+ARGS=( "$@" )
+
+cmd() {
+	echo "[#] $*" >&2
+	"$@"
+}
+
+die() {
+	echo "$PROGRAM: $*" >&2
+	exit 1
+}
+
+parse_options() {
+	local interface_section=0 line key value stripped
+	CONFIG_FILE="$1"
+	[[ $CONFIG_FILE =~ ^[a-zA-Z0-9_=+.-]{1,15}$ ]] && CONFIG_FILE="/etc/wireguard/$CONFIG_FILE.conf"
+	[[ -e $CONFIG_FILE ]] || die "\`$CONFIG_FILE' does not exist"
+	[[ $CONFIG_FILE =~ (^|/)([a-zA-Z0-9_=+.-]{1,15})\.conf$ ]] || die "The config file must be a valid interface name, followed by .conf"
+	CONFIG_FILE="$(readlink -f "$CONFIG_FILE")"
+	((($(stat -f '0%#p' "$CONFIG_FILE") & $(stat -f '0%#p' "${CONFIG_FILE%/*}") & 0007) == 0)) || echo "Warning: \`$CONFIG_FILE' is world accessible" >&2
+	INTERFACE="${BASH_REMATCH[2]}"
+	shopt -s nocasematch
+	while read -r line || [[ -n $line ]]; do
+		stripped="${line%%\#*}"
+		key="${stripped%%=*}"; key="${key##*([[:space:]])}"; key="${key%%*([[:space:]])}"
+		value="${stripped#*=}"; value="${value##*([[:space:]])}"; value="${value%%*([[:space:]])}"
+		[[ $key == "["* ]] && interface_section=0
+		[[ $key == "[Interface]" ]] && interface_section=1
+		if [[ $interface_section -eq 1 ]]; then
+			case "$key" in
+			Address) ADDRESSES+=( ${value//,/ } ); continue ;;
+			MTU) MTU="$value"; continue ;;
+			DNS) DNS+=( ${value//,/ } ); continue ;;
+			Table) TABLE="$value"; continue ;;
+			PreUp) PRE_UP+=( "$value" ); continue ;;
+			PreDown) PRE_DOWN+=( "$value" ); continue ;;
+			PostUp) POST_UP+=( "$value" ); continue ;;
+			PostDown) POST_DOWN+=( "$value" ); continue ;;
+			SaveConfig) read_bool SAVE_CONFIG "$value"; continue ;;
+			esac
+		fi
+		WG_CONFIG+="$line"$'\n'
+	done < "$CONFIG_FILE"
+	shopt -u nocasematch
+}
+
+read_bool() {
+	case "$2" in
+	true) printf -v "$1" 1 ;;
+	false) printf -v "$1" 0 ;;
+	*) die "\`$2' is neither true nor false"
+	esac
+}
+
+auto_su() {
+	[[ $UID == 0 ]] || exec doas -- "$BASH" -- "$SELF" "${ARGS[@]}"
+}
+
+
+get_real_interface() {
+	local interface diff
+	wg show interfaces >/dev/null
+	[[ -f "/var/run/wireguard/$INTERFACE.name" ]] || return 1
+	interface="$(< "/var/run/wireguard/$INTERFACE.name")"
+	[[ -n $interface && -S "/var/run/wireguard/$interface.sock" ]] || return 1
+	diff=$(( $(stat -f %m "/var/run/wireguard/$interface.sock" 2>/dev/null || echo 200) - $(stat -f %m "/var/run/wireguard/$INTERFACE.name" 2>/dev/null || echo 100) ))
+	[[ $diff -ge 2 || $diff -le -2 ]] && return 1
+	REAL_INTERFACE="$interface"
+	echo "[+] Interface for $INTERFACE is $REAL_INTERFACE" >&2
+	return 0
+}
+
+add_if() {
+	export WG_TUN_NAME_FILE="/var/run/wireguard/$INTERFACE.name"
+	mkdir -m 0700 -p "/var/run/wireguard/"
+	cmd "${WG_QUICK_USERSPACE_IMPLEMENTATION:-wireguard-go}" tun
+	get_real_interface
+}
+
+del_routes() {
+	local todelete=( ) destination gateway netif
+	[[ -n $REAL_INTERFACE ]] || return 0
+	while read -r destination _ _ _ _ netif _; do
+		[[ $netif == "$REAL_INTERFACE" ]] && todelete+=( "$destination" )
+	done < <(netstat -nr -f inet)
+	for destination in "${todelete[@]}"; do
+		cmd route -q -n delete -inet "$destination" || true
+	done
+	todelete=( )
+	while read -r destination gateway _ netif; do
+		[[ $netif == "$REAL_INTERFACE" || ( $netif == lo* && $gateway == "$REAL_INTERFACE" ) ]] && todelete+=( "$destination" )
+	done < <(netstat -nr -f inet6)
+	for destination in "${todelete[@]}"; do
+		cmd route -q -n delete -inet6 "$destination" || true
+	done
+	for destination in "${ENDPOINTS[@]}"; do
+		if [[ $destination == *:* ]]; then
+			cmd route -q -n delete -inet6 "$destination" || true
+		else
+			cmd route -q -n delete -inet "$destination" || true
+		fi
+	done
+}
+
+del_if() {
+	unset_dns
+	[[ -z $REAL_INTERFACE ]] || cmd rm -f "/var/run/wireguard/$REAL_INTERFACE.sock"
+	cmd rm -f "/var/run/wireguard/$INTERFACE.name"
+}
+
+up_if() {
+	cmd ifconfig "$REAL_INTERFACE" up
+}
+
+add_addr() {
+	local family
+	if [[ $1 == *:* ]]; then
+		family=inet6
+		[[ -n $FIRSTADDR6 ]] || FIRSTADDR6="${1%/*}"
+	else
+		family=inet
+		[[ -n $FIRSTADDR4 ]] || FIRSTADDR4="${1%/*}"
+	fi
+	cmd ifconfig "$REAL_INTERFACE" $family "$1" alias
+}
+
+set_mtu() {
+	local mtu=0 endpoint output family
+	if [[ -n $MTU ]]; then
+		cmd ifconfig "$REAL_INTERFACE" mtu "$MTU"
+		return
+	fi
+	while read -r _ endpoint; do
+		[[ $endpoint =~ ^\[?([a-z0-9:.]+)\]?:[0-9]+$ ]] || continue
+		family=inet
+		[[ ${BASH_REMATCH[1]} == *:* ]] && family=inet6
+		output="$(route -n get "-$family" "${BASH_REMATCH[1]}" || true)"
+		[[ $output =~ interface:\ ([^ ]+)$'\n' && $(ifconfig "${BASH_REMATCH[1]}") =~ mtu\ ([0-9]+) && ${BASH_REMATCH[1]} -gt $mtu ]] && mtu="${BASH_REMATCH[1]}"
+	done < <(wg show "$REAL_INTERFACE" endpoints)
+	if [[ $mtu -eq 0 ]]; then
+		read -r output < <(route -n get default || true) || true
+		[[ $output =~ interface:\ ([^ ]+)$'\n' && $(ifconfig "${BASH_REMATCH[1]}") =~ mtu\ ([0-9]+) && ${BASH_REMATCH[1]} -gt $mtu ]] && mtu="${BASH_REMATCH[1]}"
+	fi
+	[[ $mtu -gt 0 ]] || mtu=1500
+	cmd ifconfig "$REAL_INTERFACE" mtu $(( mtu - 80 ))
+}
+
+
+collect_gateways() {
+	local destination gateway
+
+	GATEWAY4=""
+	while read -r destination gateway _; do
+		[[ $destination == default ]] || continue
+		GATEWAY4="$gateway"
+		break
+	done < <(netstat -nr -f inet)
+
+	GATEWAY6=""
+	while read -r destination gateway _; do
+		[[ $destination == default ]] || continue
+		[[ $gateway == fe80:* ]] && continue
+		GATEWAY6="$gateway"
+		break
+	done < <(netstat -nr -f inet6)
+}
+
+collect_endpoints() {
+	ENDPOINTS=( )
+	while read -r _ endpoint; do
+		[[ $endpoint =~ ^\[?([a-z0-9:.]+)\]?:[0-9]+$ ]] || continue
+		ENDPOINTS+=( "${BASH_REMATCH[1]}" )
+	done < <(wg show "$REAL_INTERFACE" endpoints)
+}
+
+set_endpoint_direct_route() {
+	local old_endpoints endpoint old_gateway4 old_gateway6 remove_all_old=0 added=( )
+	old_endpoints=( "${ENDPOINTS[@]}" )
+	old_gateway4="$GATEWAY4"
+	old_gateway6="$GATEWAY6"
+	collect_gateways
+	collect_endpoints
+
+	[[ $old_gateway4 != "$GATEWAY4" || $old_gateway6 != "$GATEWAY6" ]] && remove_all_old=1
+
+	if [[ $remove_all_old -eq 1 ]]; then
+		for endpoint in "${ENDPOINTS[@]}"; do
+			[[ " ${old_endpoints[*]} " == *" $endpoint "* ]] || old_endpoints+=( "$endpoint" )
+		done
+	fi
+
+	for endpoint in "${old_endpoints[@]}"; do
+		[[ $remove_all_old -eq 0 && " ${ENDPOINTS[*]} " == *" $endpoint "* ]] && continue
+		if [[ $endpoint == *:* && $AUTO_ROUTE6 -eq 1 ]]; then
+			cmd route -q -n delete -inet6 "$endpoint" 2>/dev/null || true
+		elif [[ $AUTO_ROUTE4 -eq 1 ]]; then
+			cmd route -q -n delete -inet "$endpoint" 2>/dev/null || true
+		fi
+	done
+
+	for endpoint in "${ENDPOINTS[@]}"; do
+		if [[ $remove_all_old -eq 0 && " ${old_endpoints[*]} " == *" $endpoint "* ]]; then
+			added+=( "$endpoint" )
+			continue
+		fi
+		if [[ $endpoint == *:* && $AUTO_ROUTE6 -eq 1 ]]; then
+			if [[ -n $GATEWAY6 ]]; then
+				cmd route -q -n add -inet6 "$endpoint" -gateway "$GATEWAY6" || true
+			else
+				# Prevent routing loop
+				cmd route -q -n add -inet6 "$endpoint" ::1 -blackhole || true
+			fi
+			added+=( "$endpoint" )
+		elif [[ $AUTO_ROUTE4 -eq 1 ]]; then
+			if [[ -n $GATEWAY4 ]]; then
+				cmd route -q -n add -inet "$endpoint" -gateway "$GATEWAY4" || true
+			else
+				# Prevent routing loop
+				cmd route -q -n add -inet "$endpoint" 127.0.0.1 -blackhole || true
+			fi
+			added+=( "$endpoint" )
+		fi
+	done
+	ENDPOINTS=( "${added[@]}" )
+}
+
+monitor_daemon() {
+	echo "[+] Backgrounding route monitor" >&2
+	(trap 'del_routes; exit 0' INT TERM EXIT
+	exec >/dev/null 2>&1
+	local event
+	# TODO: this should also check to see if the endpoint actually changes
+	# in response to incoming packets, and then call set_endpoint_direct_route
+	# then too. That function should be able to gracefully cleanup if the
+	# endpoints change.
+	while read -r event; do
+		[[ $event == RTM_* ]] || continue
+		ifconfig "$REAL_INTERFACE" >/dev/null 2>&1 || break
+		[[ $AUTO_ROUTE4 -eq 1 || $AUTO_ROUTE6 -eq 1 ]] && set_endpoint_direct_route
+		# TODO: set the mtu as well, but only if up
+	done < <(route -n monitor)) & disown
+}
+
+set_dns() {
+	[[ ${#DNS[@]} -gt 0 ]] || return 0
+	# TODO: this is a horrible way of doing it. Has OpenBSD no resolvconf?
+	cmd cp /etc/resolv.conf "/etc/resolv.conf.wg-quick-backup.$INTERFACE"
+	cmd printf 'nameserver %s\n' "${DNS[@]}" > /etc/resolv.conf
+}
+
+unset_dns() {
+	[[ -f "/etc/resolv.conf.wg-quick-backup.$INTERFACE" ]] || return 0
+	cmd mv "/etc/resolv.conf.wg-quick-backup.$INTERFACE" /etc/resolv.conf
+}
+
+add_route() {
+	[[ $TABLE != off ]] || return 0
+	local family ifaceroute
+
+	if [[ $1 == *:* ]]; then
+		family=inet6
+		[[ -n $FIRSTADDR6 ]] || die "Local IPv6 address must be set to have routes"
+		ifaceroute="$FIRSTADDR6"
+	else
+		family=inet
+		[[ -n $FIRSTADDR4 ]] || die "Local IPv4 address must be set to have routes"
+		ifaceroute="$FIRSTADDR4"
+	fi
+
+	if [[ -n $TABLE && $TABLE != auto ]]; then
+		cmd route -q -n add "-$family" -rdomain "$TABLE" "$1" -iface "$ifaceroute"
+	elif [[ $1 == */0 ]]; then
+		if [[ $1 == *:* ]]; then
+			AUTO_ROUTE6=1
+			cmd route -q -n add -inet6 ::/1 -iface "$ifaceroute"
+			cmd route -q -n add -inet6 8000::/1 -iface "$ifaceroute"
+		else
+			AUTO_ROUTE4=1
+			cmd route -q -n add -inet 0.0.0.0/1 -iface "$ifaceroute"
+			cmd route -q -n add -inet 128.0.0.0/1 -iface "$ifaceroute"
+		fi
+	else
+		[[ $(route -n get "-$family" "$1" 2>/dev/null) =~ interface:\ $REAL_INTERFACE$'\n' ]] || cmd route -q -n add "-$family" "$1" -iface "$ifaceroute"
+	fi
+}
+
+set_config() {
+	cmd wg setconf "$REAL_INTERFACE" <(echo "$WG_CONFIG")
+}
+
+save_config() {
+	# TODO: actually save addresses by running ifconfig and dnses too
+	local old_umask new_config current_config address cmd
+	new_config=$'[Interface]\n'
+	for address in "${ADDRESSES[@]}"; do
+		new_config+="Address = $address"$'\n'
+	done
+	for address in "${DNS[@]}"; do
+		new_config+="DNS = $address"$'\n'
+	done
+	[[ -n $MTU ]] && new_config+="MTU = $MTU"$'\n'
+	[[ -n $TABLE ]] && new_config+="Table = $TABLE"$'\n'
+	[[ $SAVE_CONFIG -eq 0 ]] || new_config+=$'SaveConfig = true\n'
+	for cmd in "${PRE_UP[@]}"; do
+		new_config+="PreUp = $cmd"$'\n'
+	done
+	for cmd in "${POST_UP[@]}"; do
+		new_config+="PostUp = $cmd"$'\n'
+	done
+	for cmd in "${PRE_DOWN[@]}"; do
+		new_config+="PreDown = $cmd"$'\n'
+	done
+	for cmd in "${POST_DOWN[@]}"; do
+		new_config+="PostDown = $cmd"$'\n'
+	done
+	old_umask="$(umask)"
+	umask 077
+	current_config="$(cmd wg showconf "$REAL_INTERFACE")"
+	trap 'rm -f "$CONFIG_FILE.tmp"; exit' INT TERM EXIT
+	echo "${current_config/\[Interface\]$'\n'/$new_config}" > "$CONFIG_FILE.tmp" || die "Could not write configuration file"
+	sync "$CONFIG_FILE.tmp"
+	mv "$CONFIG_FILE.tmp" "$CONFIG_FILE" || die "Could not move configuration file"
+	trap - INT TERM EXIT
+	umask "$old_umask"
+}
+
+execute_hooks() {
+	local hook
+	for hook in "$@"; do
+		hook="${hook//%i/$REAL_INTERFACE}"
+		hook="${hook//%I/$INTERFACE}"
+		echo "[#] $hook" >&2
+		(eval "$hook")
+	done
+}
+
+cmd_usage() {
+	cat >&2 <<-_EOF
+	Usage: $PROGRAM [ up | down | save ] [ CONFIG_FILE | INTERFACE ]
+
+	  CONFIG_FILE is a configuration file, whose filename is the interface name
+	  followed by \`.conf'. Otherwise, INTERFACE is an interface name, with
+	  configuration found at /etc/wireguard/INTERFACE.conf. It is to be readable
+	  by wg(8)'s \`setconf' sub-command, with the exception of the following additions
+	  to the [Interface] section, which are handled by $PROGRAM:
+
+	  - Address: may be specified one or more times and contains one or more
+	    IP addresses (with an optional CIDR mask) to be set for the interface.
+	  - DNS: an optional DNS server to use while the device is up.
+	  - MTU: an optional MTU for the interface; if unspecified, auto-calculated.
+	  - Table: an optional routing table to which routes will be added; if
+	    unspecified or \`auto', the default table is used. If \`off', no routes
+	    are added.
+	  - PreUp, PostUp, PreDown, PostDown: script snippets which will be executed
+	    by bash(1) at the corresponding phases of the link, most commonly used
+	    to configure DNS. The string \`%i' is expanded to INTERFACE.
+	  - SaveConfig: if set to \`true', the configuration is saved from the current
+	    state of the interface upon shutdown.
+
+	See wg-quick(8) for more info and examples.
+	_EOF
+}
+
+cmd_up() {
+	local i
+	get_real_interface && die "\`$INTERFACE' already exists as \`$REAL_INTERFACE'"
+	trap 'del_if; del_routes; exit' INT TERM EXIT
+	execute_hooks "${PRE_UP[@]}"
+	add_if
+	set_config
+	for i in "${ADDRESSES[@]}"; do
+		add_addr "$i"
+	done
+	set_mtu
+	up_if
+	set_dns
+	for i in $(while read -r _ i; do for i in $i; do [[ $i =~ ^[0-9a-z:.]+/[0-9]+$ ]] && echo "$i"; done; done < <(wg show "$REAL_INTERFACE" allowed-ips) | sort -nr -k 2 -t /); do
+		add_route "$i"
+	done
+	[[ $AUTO_ROUTE4 -eq 1 || $AUTO_ROUTE6 -eq 1 ]] && set_endpoint_direct_route
+	monitor_daemon
+	execute_hooks "${POST_UP[@]}"
+	trap - INT TERM EXIT
+}
+
+cmd_down() {
+	if ! get_real_interface || [[ " $(wg show interfaces) " != *" $REAL_INTERFACE "* ]]; then
+		die "\`$INTERFACE' is not a WireGuard interface"
+	fi
+	execute_hooks "${PRE_DOWN[@]}"
+	[[ $SAVE_CONFIG -eq 0 ]] || save_config
+	del_if
+	unset_dns
+	execute_hooks "${POST_DOWN[@]}"
+}
+
+cmd_save() {
+	if ! get_real_interface || [[ " $(wg show interfaces) " != *" $REAL_INTERFACE "* ]]; then
+		die "\`$INTERFACE' is not a WireGuard interface"
+	fi
+	save_config
+}
+
+# ~~ function override insertion point ~~
+
+if [[ $# -eq 1 && ( $1 == --help || $1 == -h || $1 == help ) ]]; then
+	cmd_usage
+elif [[ $# -eq 2 && $1 == up ]]; then
+	auto_su
+	parse_options "$2"
+	cmd_up
+elif [[ $# -eq 2 && $1 == down ]]; then
+	auto_su
+	parse_options "$2"
+	cmd_down
+elif [[ $# -eq 2 && $1 == save ]]; then
+	auto_su
+	parse_options "$2"
+	cmd_save
+else
+	cmd_usage
+	exit 1
+fi
+
+exit 0