package/network/utils/wireguard-tools/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=$2
  20   local disabled
  21   local public_key
  22   local endpoint_host
  23   local endpoint_port
  24   local persistent_keepalive
  25   local last_handshake
  26   local idle_seconds
  27
  28   config_get_bool disabled "${cfg}" "disabled" 0
  29   config_get public_key "${cfg}" "public_key"
  30   config_get endpoint_host "${cfg}" "endpoint_host"
  31   config_get endpoint_port "${cfg}" "endpoint_port"
  32
  33   if [ "${disabled}" -eq 1 ]; then
  34     # skip disabled peers
  35     return 0
  36   fi
  37
  38   persistent_keepalive=$(wg show ${iface} persistent-keepalive | grep ${public_key} | awk '{print $2}')
  39
  40   # only process peers with endpoints and keepalive set
  41   [ -z ${endpoint_host} ] && return 0;
  42   [ -z ${persistent_keepalive} -o ${persistent_keepalive} = "off" ] && return 0;
  43
  44   # skip IP addresses
  45   # check taken from packages/net/ddns-scripts/files/dynamic_dns_functions.sh
  46   local IPV4_REGEX="[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}"
  47   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,\}\)"
  48   local IPV4=$(echo ${endpoint_host} | grep -m 1 -o "$IPV4_REGEX$")    # do not detect ip in 0.0.0.0.example.com
  49   local IPV6=$(echo ${endpoint_host} | grep -m 1 -o "$IPV6_REGEX")
  50   [ -n "${IPV4}" -o -n "${IPV6}" ] && return 0;
  51
  52   # re-resolve endpoint hostname if not responding for too long
  53   last_handshake=$(wg show ${iface} latest-handshakes | grep ${public_key} | awk '{print $2}')
  54   [ -z ${last_handshake} ] && return 0;
  55   idle_seconds=$(($(date +%s)-${last_handshake}))
  56   [ ${idle_seconds} -lt 150 ] && return 0;
  57   logger -t "wireguard_monitor" "${iface} endpoint ${endpoint_host}:${endpoint_port} is not responding for ${idle_seconds} seconds, trying to re-resolve hostname"
  58   wg set ${iface} peer ${public_key} endpoint "${endpoint_host}:${endpoint_port}"
  59 }
  60
  61 # query ubus for all active wireguard interfaces
  62 eval $(ubus -S call network.interface dump | jsonfilter -e 'wg_ifaces=@.interface[@.up=true && @.proto="wireguard"].interface')
  63
  64 # check every peer in every active wireguard interface
  65 config_load network
  66 for iface in $wg_ifaces; do
  67   config_foreach check_peer_activity "wireguard_${iface}" "${iface}"
  68 done