#!/bin/bash # SPDX-License-Identifier: GPL-2.0 # # Copyright (C) 2016-2017 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=( ) 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 CONFIG_FILE="$1" [[ $CONFIG_FILE =~ ^[a-zA-Z0-9_=+.-]{1,16}$ ]] && CONFIG_FILE="/etc/wireguard/$CONFIG_FILE.conf" [[ -e $CONFIG_FILE ]] || die "\`$CONFIG_FILE' does not exist" [[ $CONFIG_FILE =~ /?([a-zA-Z0-9_=+.-]{1,16})\.conf$ ]] || 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[1]}" shopt -s nocasematch while read -r line || [[ -n $line ]]; do key="${line%%=*}"; key="${key##*([[:space:]])}"; key="${key%%*([[:space:]])}" value="${line#*=}"; value="${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+=( ${value//,/ } ); continue ;; PreUp) PRE_UP+=( "$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() { cmd ip link add "$INTERFACE" type wireguard } del_if() { local fwmark [[ $HAVE_SET_DNS -eq 0 ]] || unset_dns fwmark="$(wg show "$INTERFACE" fwmark)" DEFAULT_TABLE=0 [[ $fwmark != off ]] && DEFAULT_TABLE=$(( fwmark )) if [[ $DEFAULT_TABLE -ne 0 ]]; then while [[ $(ip -4 rule show) == *"lookup $DEFAULT_TABLE"* ]]; do cmd ip -4 rule delete table $DEFAULT_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 $DEFAULT_TABLE"* ]]; do cmd ip -6 rule delete table $DEFAULT_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" } HAVE_SET_DNS=0 set_dns() { [[ ${#DNS[@]} -gt 0 ]] || return 0 printf 'nameserver %s\n' "${DNS[@]}" | cmd resolvconf -a "tun.$INTERFACE" -m 0 -x HAVE_SET_DNS=1 } unset_dns() { [[ ${#DNS[@]} -gt 0 ]] || return 0 cmd resolvconf -d "tun.$INTERFACE" } add_route() { if [[ $1 == 0.0.0.0/0 || $1 =~ ^[0:]+/0$ ]]; then add_default "$1" else cmd ip route add "$1" dev "$INTERFACE" fi } DEFAULT_TABLE= add_default() { if [[ -z $DEFAULT_TABLE ]]; then DEFAULT_TABLE=51820 while [[ -n $(ip -4 route show table $DEFAULT_TABLE) || -n $(ip -6 route show table $DEFAULT_TABLE) ]]; do ((DEFAULT_TABLE++)) done fi local proto=-4 [[ $1 == *:* ]] && proto=-6 cmd wg set "$INTERFACE" fwmark $DEFAULT_TABLE cmd ip $proto route add "$1" dev "$INTERFACE" table $DEFAULT_TABLE cmd ip $proto rule add not fwmark $DEFAULT_TABLE table $DEFAULT_TABLE cmd ip $proto rule add table main suppress_prefixlength 0 local key value 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 "tun.$INTERFACE" 2>/dev/null) [[ -n $MTU && $(ip link show dev "$INTERFACE") =~ mtu\ ([0-9]+) ]] && new_config+="MTU = ${BASH_REMATCH[1]}"$'\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. - 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 [[ $(ip route get "$i" 2>/dev/null) == *dev\ $INTERFACE\ * ]] || add_route "$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