Initial commit

package/network/utils/wireguard-tools/files/wireguard_watchdog

@@ -0,0 +1,68 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+#
+# Copyright (C) 2018 Aleksandr V. Piskunov <aleksandr.v.piskunov@gmail.com>.
+# Copyright (C) 2015-2018 Jason A. Donenfeld <Jason@zx2c4.com>. 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=$2
+  local disabled
+  local public_key
+  local endpoint_host
+  local endpoint_port
+  local persistent_keepalive
+  local last_handshake
+  local idle_seconds
+
+  config_get_bool disabled "${cfg}" "disabled" 0
+  config_get public_key "${cfg}" "public_key"
+  config_get endpoint_host "${cfg}" "endpoint_host"
+  config_get endpoint_port "${cfg}" "endpoint_port"
+
+  if [ "${disabled}" -eq 1 ]; then
+    # skip disabled peers
+    return 0
+  fi
+
+  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
+eval $(ubus -S call network.interface dump | jsonfilter -e 'wg_ifaces=@.interface[@.up=true && @.proto="wireguard"].interface')
+
+# 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