#!/usr/local/bin/bash # SPDX-License-Identifier: GPL-2.0 # # Copyright (C) 2015-2019 Jason A. Donenfeld . 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: $*" >&2 exit 1 } CONFIG_SEARCH_PATHS=( /etc/wireguard /usr/local/etc/wireguard ) unset ORIGINAL_TMPDIR make_temp() { local old_umask [[ -v ORIGINAL_TMPDIR ]] && export TMPDIR="$ORIGINAL_TMPDIR" ORIGINAL_TMPDIR="$TMPDIR" [[ -z $TMPDIR ]] && unset TMPDIR old_umask="$(umask)" umask 077 export TMPDIR="$(mktemp -d)" umask "$old_umask" [[ -d $TMPDIR ]] || die "Unable to create safe temporary directory" CLEANUP_TMPDIR="$TMPDIR" } clean_temp() { [[ -n $CLEANUP_TMPDIR ]] && rm -rf "$CLEANUP_TMPDIR" } parse_options() { local interface_section=0 line key value stripped path CONFIG_FILE="$1" if [[ $CONFIG_FILE =~ ^[a-zA-Z0-9_=+.-]{1,15}$ ]]; then for path in "${CONFIG_SEARCH_PATHS[@]}"; do CONFIG_FILE="$path/$1.conf" [[ -e $CONFIG_FILE ]] && break done fi [[ -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() { [[ $UID == 0 ]] || exec sudo -p "$PROGRAM must be run as root. Please enter the password for %u to continue: " -- "$BASH" -- "$SELF" "${ARGS[@]}" } add_if() { cmd "${WG_QUICK_USERSPACE_IMPLEMENTATION:-wireguard-go}" "$INTERFACE" } del_routes() { local todelete=( ) destination gateway netif while read -r destination _ _ _ _ netif _; do [[ $netif == "$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 [[ $netif == "$INTERFACE" || ( $netif == lo* && $gateway == "$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 } if_exists() { # HACK: The goal is simply to determine whether or not the interface exists. The # straight-forward way of doing this would be `ifconfig $INTERFACE`, but this # invokes the SIOCGIFSTATUS ioctl, which races with interface shutdown inside # the tun driver, resulting in a kernel panic. So we work around it the stupid # way by using the one utility that appears to call if_nametoindex fairly early # and fails if it doesn't exist: `arp`. if arp -i "$INTERFACE" -a -n >/dev/null 2>&1; then return 0 else return 1 fi } del_if() { [[ $HAVE_SET_DNS -eq 0 ]] || unset_dns cmd rm -f "/var/run/wireguard/$INTERFACE.sock" while if_exists; do # HACK: it would be nice to `route monitor` here and wait for RTM_IFANNOUNCE # but it turns out that the announcement is made before the interface # disappears so we sometimes get a hang. So, we're instead left with polling # in a sleep loop like this. sleep 0.1 done } up_if() { cmd ifconfig "$INTERFACE" up } add_addr() { if [[ $1 == *:* ]]; then cmd ifconfig "$INTERFACE" inet6 "$1" alias else cmd ifconfig "$INTERFACE" inet "$1" "${1%%/*}" alias fi } set_mtu() { local mtu=0 endpoint output family if [[ -n $MTU ]]; then cmd ifconfig "$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 "$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 [[ $mtu -gt 0 ]] || mtu=1500 cmd ifconfig "$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 [[ $destination == default ]] || continue GATEWAY6="$gateway" break done < <(netstat -nr -f inet6) } collect_endpoints() { ENDPOINTS=( ) while read -r _ endpoint; do [[ $endpoint =~ ^\[?([a-z0-9:.]+)\]?:[0-9]+$ ]] || continue ENDPOINTS+=( "${BASH_REMATCH[1]}" ) done < <(wg show "$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 (make_temp trap 'del_routes; clean_temp; 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 [[ $event == RTM_* ]] || continue [[ -e /var/run/wireguard/$INTERFACE.sock ]] || break if_exists || 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 } HAVE_SET_DNS=0 set_dns() { [[ ${#DNS[@]} -gt 0 ]] || return 0 printf 'nameserver %s\n' "${DNS[@]}" | cmd resolvconf -a "$INTERFACE" -x HAVE_SET_DNS=1 } unset_dns() { [[ ${#DNS[@]} -gt 0 ]] || return 0 cmd resolvconf -d "$INTERFACE" } add_route() { [[ $TABLE != off ]] || return 0 local family=inet [[ $1 == *:* ]] && family=inet6 if [[ -n $TABLE && $TABLE != auto ]]; then cmd route -q -n add "-$family" -fib "$TABLE" "$1" -interface "$INTERFACE" elif [[ $1 == */0 ]]; then if [[ $1 == *:* ]]; then AUTO_ROUTE6=1 cmd route -q -n add -inet6 ::/1 -interface "$INTERFACE" cmd route -q -n add -inet6 8000::/1 -interface "$INTERFACE" else AUTO_ROUTE4=1 cmd route -q -n add -inet 0.0.0.0/1 -interface "$INTERFACE" cmd route -q -n add -inet 128.0.0.0/1 -interface "$INTERFACE" fi else [[ $(route -n get "-$family" "$1" 2>/dev/null) =~ interface:\ $INTERFACE$'\n' ]] || cmd route -q -n add "-$family" "$1" -interface "$INTERFACE" fi } set_config() { cmd wg setconf "$INTERFACE" <(echo "$WG_CONFIG") } save_config() { local old_umask new_config current_config address cmd new_config=$'[Interface]\n' { read -r _; while read -r _ _ _ address _; do new_config+="Address = $address"$'\n' done } < <(netstat -I "$INTERFACE" -n -W -f inet) { read -r _; while read -r _ _ _ address _; do new_config+="Address = $address"$'\n' done } < <(netstat -I "$INTERFACE" -n -W -f inet6) while read -r address; do [[ $address =~ ^nameserver\ ([a-zA-Z0-9_=+:%.-]+)$ ]] && new_config+="DNS = ${BASH_REMATCH[1]}"$'\n' done < <(resolvconf -l "$INTERFACE" 2>/dev/null) [[ -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 "$INTERFACE")" trap 'rm -f "$CONFIG_FILE.tmp"; clean_temp; 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 'clean_temp; exit' 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 | strip ] [ 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: ${CONFIG_SEARCH_PATHS[@]/%//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 $(ifconfig "$INTERFACE" 2>/dev/null) ]] || die "\`$INTERFACE' already exists" trap 'del_if; del_routes; clean_temp; exit' INT TERM EXIT execute_hooks "${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 [[ $AUTO_ROUTE4 -eq 1 || $AUTO_ROUTE6 -eq 1 ]] && set_endpoint_direct_route monitor_daemon execute_hooks "${POST_UP[@]}" trap 'clean_temp; exit' 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 } cmd_strip() { echo "$WG_CONFIG" } # ~~ function override insertion point ~~ make_temp trap 'clean_temp; exit' INT TERM EXIT 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 elif [[ $# -eq 2 && $1 == strip ]]; then auto_su parse_options "$2" cmd_strip else cmd_usage exit 1 fi exit 0