#!/bin/bash # # Generate OpenVPN configs # USE_DEFAULT_ROUTE=true TMP_PUSH_CONFIGFILE=$(mktemp -t vpn_push.XXXXXXX) TMP_ROUTE_CONFIGFILE=$(mktemp -t vpn_route.XXXXXXX) TMP_EXTRA_CONFIGFILE=$(mktemp -t vpn_extra.XXXXXXX) #Traceback on Error and Exit come from https://docwhat.org/tracebacks-in-bash/ set -eu _showed_traceback=f traceback() { # Hide the traceback() call. local -i start=$(( ${1:-0} + 1 )) local -i end=${#BASH_SOURCE[@]} local -i i=0 local -i j=0 echo "Traceback (last called is first):" 1>&2 for ((i=${start}; i < ${end}; i++)); do j=$(( $i - 1 )) local function="${FUNCNAME[$i]}" local file="${BASH_SOURCE[$i]}" local line="${BASH_LINENO[$j]}" echo " ${function}() in ${file}:${line}" 1>&2 done } on_error() { local _ec="$?" local _cmd="${BASH_COMMAND:-unknown}" traceback 1 _showed_traceback=t echo "The command ${_cmd} exited with exit code ${_ec}." 1>&2 } trap on_error ERR on_exit() { echo "Cleaning up before Exit ..." rm -f $TMP_PUSH_CONFIGFILE rm -f $TMP_ROUTE_CONFIGFILE rm -f $TMP_EXTRA_CONFIGFILE local _ec="$?" if [[ $_ec != 0 && "${_showed_traceback}" != t ]]; then traceback 1 fi } trap on_exit EXIT # Convert 1.2.3.4/24 -> 255.255.255.0 cidr2mask() { local i local subnetmask="" local cidr=${1#*/} local full_octets=$(($cidr/8)) local partial_octet=$(($cidr%8)) for ((i=0;i<4;i+=1)); do if [ $i -lt $full_octets ]; then subnetmask+=255 elif [ $i -eq $full_octets ]; then subnetmask+=$((256 - 2**(8-$partial_octet))) else subnetmask+=0 fi [ $i -lt 3 ] && subnetmask+=. done echo $subnetmask } # Used often enough to justify a function getroute() { echo ${1%/*} $(cidr2mask $1) } usage() { echo "usage: $0 [-d]" echo " -u SERVER_PUBLIC_URL" echo " [-e EXTRA_SERVER_CONFIG ]" echo " [-f FRAGMENT ]" echo " [-n DNS_SERVER ...]" echo " [-p PUSH ...]" echo " [-r ROUTE ...]" echo " [-s SERVER_SUBNET]" echo echo "optional arguments:" echo " -2 Enable two factor authentication using Google Authenticator." echo " -a Authenticate packets with HMAC using the given message digest algorithm (auth)." echo " -c Enable client-to-client option" echo " -C A list of allowable TLS ciphers delimited by a colon (cipher)." echo " -d Disable NAT routing and default route" echo " -D Do not push dns servers" echo " -m Set client MTU" echo " -N Configure NAT to access external server network" echo " -t Use TAP device (instead of TUN device)" echo " -T Encrypt packets with the given cipher algorithm instead of the default one (tls-cipher)." echo " -z Enable comp-lzo compression." } process_route_config() { local ovpn_route_config='' ovpn_route_config="$1" # If user passed "0" skip this, assume no extra routes [[ "$ovpn_route_config" == "0" ]] && break; echo "Processing Route Config: '${ovpn_route_config}'" [[ -n "$ovpn_route_config" ]] && echo "route $(getroute $ovpn_route_config)" >> "$TMP_ROUTE_CONFIGFILE" } process_push_config() { local ovpn_push_config='' ovpn_push_config="$1" echo "Processing PUSH Config: '${ovpn_push_config}'" [[ -n "$ovpn_push_config" ]] && echo "push $ovpn_push_config" >> "$TMP_PUSH_CONFIGFILE" } process_extra_config() { local ovpn_extra_config='' ovpn_extra_config="$1" echo "Processing Extra Config: '${ovpn_extra_config}'" [[ -n "$ovpn_extra_config" ]] && echo "$ovpn_extra_config" >> "$TMP_EXTRA_CONFIGFILE" } if [ "${DEBUG:-}" == "1" ]; then set -x fi set -e if [ -z "${OPENVPN:-}" ]; then export OPENVPN="$PWD" fi if [ -z "${EASYRSA_PKI:-}" ]; then export EASYRSA_PKI="$OPENVPN/pki" fi OVPN_ENV=${OPENVPN}/ovpn_env.sh OVPN_SERVER=192.168.255.0/24 OVPN_DEFROUTE=1 OVPN_NAT=0 OVPN_DNS=1 OVPN_DEVICE="tun" OVPN_DEVICEN=0 OVPN_DNS_SERVERS=("8.8.8.8" "8.8.4.4") TMP_DNS_SERVERS=() OVPN_TLS_CIPHER='' OVPN_CIPHER='' OVPN_AUTH='' OVPN_EXTRA_CONFIG='' # Import defaults if present [ -r "$OVPN_ENV" ] && source "$OVPN_ENV" # Parse arguments while getopts ":a:e:C:T:r:s:du:cp:n:DNmf:tz2" opt; do case $opt in a) OVPN_AUTH="$OPTARG" ;; e) process_extra_config "$OPTARG" ;; C) OVPN_CIPHER="$OPTARG" ;; T) OVPN_TLS_CIPHER="$OPTARG" ;; r) USE_DEFAULT_ROUTE=false process_route_config "$OPTARG" ;; s) OVPN_SERVER=$OPTARG ;; d) OVPN_DEFROUTE=0 ;; u) OVPN_SERVER_URL=$OPTARG ;; c) OVPN_CLIENT_TO_CLIENT=1 ;; p) process_push_config "$OPTARG" ;; n) TMP_DNS_SERVERS+=("$OPTARG") ;; D) OVPN_DNS=0 ;; N) OVPN_NAT=1 ;; m) OVPN_MTU=$OPTARG ;; t) OVPN_DEVICE="tap" ;; z) OVPN_COMP_LZO=1 ;; 2) OVPN_OTP_AUTH=1 ;; f) OVPN_FRAGMENT=$OPTARG ;; \?) set +x echo "Invalid option: -$OPTARG" >&2 usage exit 1 ;; :) set +x echo "Option -$OPTARG requires an argument." >&2 usage exit 1 ;; esac done # Create ccd directory for static routes [ ! -d "${OPENVPN:-}/ccd" ] && mkdir -p ${OPENVPN:-}/ccd # if dns servers were not defined with -n, use google nameservers [ ${#TMP_DNS_SERVERS[@]} -gt 0 ] && OVPN_DNS_SERVERS=("${TMP_DNS_SERVERS[@]}") # Server name is in the form "udp://vpn.example.com:1194" if [[ "${OVPN_SERVER_URL:-}" =~ ^((udp|tcp)://)?([0-9a-zA-Z\.\-]+)(:([0-9]+))?$ ]]; then OVPN_PROTO=${BASH_REMATCH[2]}; OVPN_CN=${BASH_REMATCH[3]}; OVPN_PORT=${BASH_REMATCH[5]}; else set +x echo "Common name not specified, see '-u'" usage exit 1 fi # Apply defaults [ -z "$OVPN_PROTO" ] && OVPN_PROTO=udp [ -z "$OVPN_PORT" ] && OVPN_PORT=1194 [ $USE_DEFAULT_ROUTE ] && process_route_config "192.168.254.0/24" export OVPN_SERVER OVPN_ROUTES OVPN_DEFROUTE export OVPN_SERVER_URL OVPN_ENV OVPN_PROTO OVPN_CN OVPN_PORT export OVPN_CLIENT_TO_CLIENT OVPN_PUSH OVPN_NAT OVPN_DNS OVPN_MTU OVPN_DEVICE export OVPN_TLS_CIPHER OVPN_CIPHER OVPN_AUTH export OVPN_COMP_LZO export OVPN_OTP_AUTH export OVPN_FRAGMENT # Preserve config if [ -f "$OVPN_ENV" ]; then bak_env=$OVPN_ENV.$(date +%s).bak echo "Backing up $OVPN_ENV -> $bak_env" mv "$OVPN_ENV" "$bak_env" fi export | grep OVPN_ > "$OVPN_ENV" conf=${OPENVPN:-}/openvpn.conf if [ -f "$conf" ]; then bak=$conf.$(date +%s).bak echo "Backing up $conf -> $bak" mv "$conf" "$bak" fi cat > "$conf" <> "$conf" [ -n "$OVPN_CIPHER" ] && echo "cipher $OVPN_CIPHER" >> "$conf" [ -n "$OVPN_AUTH" ] && echo "auth $OVPN_AUTH" >> "$conf" [ -n "${OVPN_CLIENT_TO_CLIENT:-}" ] && echo "client-to-client" >> "$conf" [ -n "${OVPN_COMP_LZO:-}" ] && echo "comp-lzo" >> "$conf" [ -n "${OVPN_FRAGMENT:-}" ] && echo "fragment $OVPN_FRAGMENT" >> "$conf" [ "$OVPN_DNS" == "1" ] && for i in "${OVPN_DNS_SERVERS[@]}"; do process_push_config "dhcp-option DNS $i" done # Append route commands echo -e "\n### Route Configurations Below" >> "$conf" cat $TMP_ROUTE_CONFIGFILE >> "$conf" # Append push commands echo -e "\n### Push Configurations Below" >> "$conf" cat $TMP_PUSH_CONFIGFILE >> "$conf" # Optional OTP authentication support if [ -n "${OVPN_OTP_AUTH:-}" ]; then echo -e "\n\n# Enable OTP+PAM for user authentication" >> "$conf" echo "plugin /usr/lib/openvpn/plugins/openvpn-plugin-auth-pam.so openvpn" >> "$conf" echo "reneg-sec 0" >> "$conf" fi echo -e "\n### Extra Configurations Below" >> "$conf" cat $TMP_EXTRA_CONFIGFILE >> "$conf" set +e # Clean-up duplicate configs if diff -q "${bak_env:-}" "$OVPN_ENV" 2>/dev/null; then echo "Removing duplicate back-up: $bak_env" rm -fv "$bak_env" fi if diff -q "${bak:-}" "$conf" 2>/dev/null; then echo "Removing duplicate back-up: $bak" rm -fv "$bak" fi echo "Successfully generated config"