From 3e6bb79515e3919eaee80397a115b6a4f9f2b96a Mon Sep 17 00:00:00 2001
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: Mon, 14 May 2018 18:14:55 +0200
Subject: tools: reorganize for multiplatform wg-quick

---
 src/tools/wg-quick/linux.bash | 334 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 334 insertions(+)
 create mode 100755 src/tools/wg-quick/linux.bash

(limited to 'src/tools/wg-quick/linux.bash')

diff --git a/src/tools/wg-quick/linux.bash b/src/tools/wg-quick/linux.bash
new file mode 100755
index 0000000..cd66b4d
--- /dev/null
+++ b/src/tools/wg-quick/linux.bash
@@ -0,0 +1,334 @@
+#!/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="${0##*/}"
+ARGS=( "$@" )
+
+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")"
+	((($(stat -c '0%#a' "$CONFIG_FILE") & $(stat -c '0%#a' "${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
+}
+
+cmd() {
+	echo "[#] $*" >&2
+	"$@"
+}
+
+die() {
+	echo "$PROGRAM: $*" >&2
+	exit 1
+}
+
+auto_su() {
+	[[ $UID == 0 ]] || exec sudo -p "$PROGRAM must be run as root. Please enter the password for %u to continue: " "$SELF" "${ARGS[@]}"
+}
+
+add_if() {
+	local ret
+	if ! cmd ip link add "$INTERFACE" type wireguard; then
+		ret=$?
+		[[ -e /sys/module/wireguard ]] || ! command -v wireguard-go >/dev/null && return $ret
+		echo "[!] Missing WireGuard kernel module. Falling back to slow userspace implementation."
+		cmd wireguard-go "$INTERFACE"
+	fi
+}
+
+del_if() {
+	local table
+	[[ $HAVE_SET_DNS -eq 0 ]] || unset_dns
+	if [[ -z $TABLE || $TABLE == auto ]] && get_fwmark table && [[ $(wg show "$INTERFACE" allowed-ips) =~ /0(\ |$'\n'|$) ]]; then
+		while [[ $(ip -4 rule show) == *"lookup $table"* ]]; do
+			cmd ip -4 rule delete table $table
+		done
+		while [[ $(ip -4 rule show) == *"from all lookup main suppress_prefixlength 0"* ]]; do
+			cmd ip -4 rule delete table main suppress_prefixlength 0
+		done
+		while [[ $(ip -6 rule show) == *"lookup $table"* ]]; do
+			cmd ip -6 rule delete table $table
+		done
+		while [[ $(ip -6 rule show) == *"from all lookup main suppress_prefixlength 0"* ]]; do
+			cmd ip -6 rule delete table main suppress_prefixlength 0
+		done
+	fi
+	cmd ip link delete dev "$INTERFACE"
+}
+
+up_if() {
+	cmd ip link set "$INTERFACE" up
+}
+
+add_addr() {
+	cmd ip address add "$1" dev "$INTERFACE"
+}
+
+set_mtu() {
+	local mtu=0 endpoint output
+	if [[ -n $MTU ]]; then
+		cmd ip link set mtu "$MTU" dev "$INTERFACE"
+		return
+	fi
+	while read -r _ endpoint; do
+		[[ $endpoint =~ ^\[?([a-z0-9:.]+)\]?:[0-9]+$ ]] || continue
+		output="$(ip route get "${BASH_REMATCH[1]}" || true)"
+		[[ ( $output =~ mtu\ ([0-9]+) || ( $output =~ dev\ ([^ ]+) && $(ip link show dev "${BASH_REMATCH[1]}") =~ mtu\ ([0-9]+) ) ) && ${BASH_REMATCH[1]} -gt $mtu ]] && mtu="${BASH_REMATCH[1]}"
+	done < <(wg show "$INTERFACE" endpoints)
+	if [[ $mtu -eq 0 ]]; then
+		read -r output < <(ip route show default || true) || true
+		[[ ( $output =~ mtu\ ([0-9]+) || ( $output =~ dev\ ([^ ]+) && $(ip link show dev "${BASH_REMATCH[1]}") =~ mtu\ ([0-9]+) ) ) && ${BASH_REMATCH[1]} -gt $mtu ]] && mtu="${BASH_REMATCH[1]}"
+	fi
+	[[ $mtu -gt 0 ]] || mtu=1500
+	cmd ip link set mtu $(( mtu - 80 )) dev "$INTERFACE"
+}
+
+resolvconf_iface_prefix() {
+	[[ -f /etc/resolvconf/interface-order ]] || return 0
+	local iface
+	while read -r iface; do
+		[[ $iface =~ ^([A-Za-z0-9-]+)\*$ ]] || continue
+		echo "${BASH_REMATCH[1]}." && return 0
+	done < /etc/resolvconf/interface-order
+}
+
+HAVE_SET_DNS=0
+set_dns() {
+	[[ ${#DNS[@]} -gt 0 ]] || return 0
+	printf 'nameserver %s\n' "${DNS[@]}" | cmd resolvconf -a "$(resolvconf_iface_prefix)$INTERFACE" -m 0 -x
+	HAVE_SET_DNS=1
+}
+
+unset_dns() {
+	[[ ${#DNS[@]} -gt 0 ]] || return 0
+	cmd resolvconf -d "$(resolvconf_iface_prefix)$INTERFACE"
+}
+
+add_route() {
+	[[ $TABLE != off ]] || return 0
+
+	if [[ -n $TABLE && $TABLE != auto ]]; then
+		cmd ip route add "$1" dev "$INTERFACE" table "$TABLE"
+	elif [[ $1 == */0 ]]; then
+		add_default "$1"
+	else
+		[[ $(ip route get "$i" 2>/dev/null) == *dev\ $INTERFACE\ * ]] || cmd ip route add "$1" dev "$INTERFACE"
+	fi
+}
+
+get_fwmark() {
+	local fwmark
+	fwmark="$(wg show "$INTERFACE" fwmark)" || return 1
+	[[ -n $fwmark && $fwmark != off ]] || return 1
+	printf -v "$1" "%d" "$fwmark"
+	return 0
+}
+
+add_default() {
+	local table proto key value
+	if ! get_fwmark table; then
+		table=51820
+		while [[ -n $(ip -4 route show table $table) || -n $(ip -6 route show table $table) ]]; do
+			((table++))
+		done
+		cmd wg set "$INTERFACE" fwmark $table
+	fi
+	proto=-4
+	[[ $1 == *:* ]] && proto=-6
+	cmd ip $proto route add "$1" dev "$INTERFACE" table $table
+	cmd ip $proto rule add not fwmark $table table $table
+	cmd ip $proto rule add table main suppress_prefixlength 0
+	while read -r key _ value; do
+		[[ $value -eq 1 ]] && sysctl -q "$key=2"
+	done < <(sysctl -a -r '^net\.ipv4.conf\.[^ .=]+\.rp_filter$')
+	return 0
+}
+
+set_config() {
+	cmd wg setconf "$INTERFACE" <(echo "$WG_CONFIG")
+}
+
+save_config() {
+	local old_umask new_config current_config address cmd
+	[[ $(ip -all -brief address show dev "$INTERFACE") =~ ^$INTERFACE\ +\ [A-Z]+\ +(.+)$ ]] || true
+	new_config=$'[Interface]\n'
+	for address in ${BASH_REMATCH[1]}; do
+		new_config+="Address = $address"$'\n'
+	done
+	while read -r address; do
+		[[ $address =~ ^nameserver\ ([a-zA-Z0-9_=+:%.-]+)$ ]] && new_config+="DNS = ${BASH_REMATCH[1]}"$'\n'
+	done < <(resolvconf -l "$(resolvconf_iface_prefix)$INTERFACE" 2>/dev/null || cat "/etc/resolvconf/run/interface/$(resolvconf_iface_prefix)$INTERFACE" 2>/dev/null)
+	[[ -n $MTU && $(ip link show dev "$INTERFACE") =~ mtu\ ([0-9]+) ]] && new_config+="MTU = ${BASH_REMATCH[1]}"$'\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 "$INTERFACE")"
+	trap 'rm -f "$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="${hook//%i/$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
+	[[ -z $(ip link show dev "$INTERFACE" 2>/dev/null) ]] || die "\`$INTERFACE' already exists"
+	trap 'del_if; exit' INT TERM EXIT
+	execute_hooks "${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 "$i"; done; done < <(wg show "$INTERFACE" allowed-ips) | sort -nr -k 2 -t /); do
+		add_route "$i"
+	done
+	execute_hooks "${POST_UP[@]}"
+	trap - INT TERM EXIT
+}
+
+cmd_down() {
+	[[ " $(wg show interfaces) " == *" $INTERFACE "* ]] || die "\`$INTERFACE' is not a WireGuard interface"
+	execute_hooks "${PRE_DOWN[@]}"
+	[[ $SAVE_CONFIG -eq 0 ]] || save_config
+	del_if
+	unset_dns
+	execute_hooks "${POST_DOWN[@]}"
+}
+
+cmd_save() {
+	[[ " $(wg show interfaces) " == *" $INTERFACE "* ]] || die "\`$INTERFACE' is not a WireGuard interface"
+	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
-- 
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