package/network/services/wireguard/files/wireguard_watchdog

   1 #!/bin/sh
   2 # SPDX-License-Identifier: GPL-2.0
   3 #
   4 # Copyright (C) 2018 Aleksandr V. Piskunov <aleksandr.v.piskunov@gmail.com>.
   5 # Copyright (C) 2015-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
   6 #
   7 # This watchdog script tries to re-resolve hostnames for inactive WireGuard peers.
   8 # Use it for peers with a frequently changing dynamic IP.
   9 # persistent_keepalive must be set, recommended value is 25 seconds.
  10 #
  11 # Run this script from cron every minute:
  12 # echo '* * * * * /usr/bin/wireguard_watchdog' >> /etc/crontabs/root
  13
  14
  15 . /lib/functions.sh
  16
  17 check_peer_activity() {
  18   local cfg=$1
  19   local iface=$2
  20   local public_key
  21   local endpoint_host
  22   local endpoint_port
  23   local persistent_keepalive
  24   local last_handshake
  25   local idle_seconds
  26
  27   config_get public_key "${cfg}" "public_key"
  28   config_get endpoint_host "${cfg}" "endpoint_host"
  29   config_get endpoint_port "${cfg}" "endpoint_port"
  30   persistent_keepalive=`wg show ${iface} persistent-keepalive | grep ${public_key} | awk '{print $2}'`
  31
  32   # only process peers with endpoints and keepalive set
  33   [ -z ${endpoint_host} ] && return 0;
  34   [ -z ${persistent_keepalive} -o ${persistent_keepalive} = "off" ] && return 0;
  35
  36   # skip IP addresses
  37   # check taken from packages/net/ddns-scripts/files/dynamic_dns_functions.sh
  38   local IPV4_REGEX="[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}"
  39   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,\}\)"
  40   local IPV4=$(echo ${endpoint_host} | grep -m 1 -o "$IPV4_REGEX$")    # do not detect ip in 0.0.0.0.example.com
  41   local IPV6=$(echo ${endpoint_host} | grep -m 1 -o "$IPV6_REGEX")
  42   [ -n "${IPV4}" -o -n "${IPV6}" ] && return 0;
  43
  44   # re-resolve endpoint hostname if not responding for too long
  45   last_handshake=`wg show ${iface} latest-handshakes | grep ${public_key} | awk '{print $2}'`
  46   [ -z ${last_handshake} ] && return 0;
  47   idle_seconds=$((`date +%s`-${last_handshake}))
  48   [ ${idle_seconds} -lt 150 ] && return 0;
  49   logger -t "wireguard_monitor" "${iface} endpoint ${endpoint_host}:${endpoint_port} is not responding for ${idle_seconds} seconds, trying to re-resolve hostname"
  50   wg set ${iface} peer ${public_key} endpoint "${endpoint_host}:${endpoint_port}"
  51 }
  52
  53 # query ubus for all active wireguard interfaces
  54 wg_ifaces=`ubus -S call network.interface dump | jsonfilter -e '@.interface[@.up=true]' | jsonfilter -a -e '@[@.proto="wireguard"].interface' | tr "\n" " "`
  55
  56 # check every peer in every active wireguard interface
  57 config_load network
  58 for iface in $wg_ifaces; do
  59   config_foreach check_peer_activity "wireguard_${iface}" "${iface}"
  60 done