#!/bin/sh # SPDX-License-Identifier: GPL-2.0 # # Copyright (C) 2018 Aleksandr V. Piskunov . # Copyright (C) 2015-2018 Jason A. Donenfeld . All Rights Reserved. # # This watchdog script tries to re-resolve hostnames for inactive WireGuard peers. # Use it for peers with a frequently changing dynamic IP. # persistent_keepalive must be set, recommended value is 25 seconds. # # Run this script from cron every minute: # echo '* * * * * /usr/bin/wireguard_watchdog' >> /etc/crontabs/root . /lib/functions.sh check_peer_activity() { local cfg=$1 local iface=$2 local public_key local endpoint_host local endpoint_port local persistent_keepalive local last_handshake local idle_seconds config_get public_key "${cfg}" "public_key" config_get endpoint_host "${cfg}" "endpoint_host" config_get endpoint_port "${cfg}" "endpoint_port" persistent_keepalive=`wg show ${iface} persistent-keepalive | grep ${public_key} | awk '{print $2}'` # only process peers with endpoints and keepalive set [ -z ${endpoint_host} ] && return 0; [ -z ${persistent_keepalive} -o ${persistent_keepalive} = "off" ] && return 0; # skip IP addresses # check taken from packages/net/ddns-scripts/files/dynamic_dns_functions.sh local IPV4_REGEX="[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}" local IPV6_REGEX="\(\([0-9A-Fa-f]\{1,4\}:\)\{1,\}\)\(\([0-9A-Fa-f]\{1,4\}\)\{0,1\}\)\(\(:[0-9A-Fa-f]\{1,4\}\)\{1,\}\)" local IPV4=$(echo ${endpoint_host} | grep -m 1 -o "$IPV4_REGEX$") # do not detect ip in 0.0.0.0.example.com local IPV6=$(echo ${endpoint_host} | grep -m 1 -o "$IPV6_REGEX") [ -n "${IPV4}" -o -n "${IPV6}" ] && return 0; # re-resolve endpoint hostname if not responding for too long last_handshake=`wg show ${iface} latest-handshakes | grep ${public_key} | awk '{print $2}'` [ -z ${last_handshake} ] && return 0; idle_seconds=$((`date +%s`-${last_handshake})) [ ${idle_seconds} -lt 150 ] && return 0; logger -t "wireguard_monitor" "${iface} endpoint ${endpoint_host}:${endpoint_port} is not responding for ${idle_seconds} seconds, trying to re-resolve hostname" wg set ${iface} peer ${public_key} endpoint "${endpoint_host}:${endpoint_port}" } # query ubus for all active wireguard interfaces wg_ifaces=`ubus -S call network.interface dump | jsonfilter -e '@.interface[@.up=true]' | jsonfilter -a -e '@[@.proto="wireguard"].interface' | tr "\n" " "` # check every peer in every active wireguard interface config_load network for iface in $wg_ifaces; do config_foreach check_peer_activity "wireguard_${iface}" "${iface}" done