wireguard-tools: add wireguard_watchdog script

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

Signed-off-by: Aleksandr V. Piskunov <aleksandr.v.piskunov@gmail.com>
[bump the package release]
Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
This commit is contained in:
Aleksandr V. Piskunov 2018-07-01 15:40:31 +03:00 committed by Kevin Darbyshire-Bryant
parent 2dcd955aea
commit 20c4819c7b
2 changed files with 63 additions and 2 deletions

View file

@ -12,7 +12,7 @@ include $(INCLUDE_DIR)/kernel.mk
PKG_NAME:=wireguard
PKG_VERSION:=0.0.20180718
PKG_RELEASE:=1
PKG_RELEASE:=2
PKG_SOURCE:=WireGuard-$(PKG_VERSION).tar.xz
PKG_SOURCE_URL:=https://git.zx2c4.com/WireGuard/snapshot/
@ -84,12 +84,13 @@ define Package/wireguard-tools/description
$(call Package/wireguard/Default/description)
This package provides the userspace control program for WireGuard,
`wg(8)`, and a netifd protocol helper.
`wg(8)`, a netifd protocol helper, and a re-resolve watchdog script.
endef
define Package/wireguard-tools/install
$(INSTALL_DIR) $(1)/usr/bin/
$(INSTALL_BIN) $(PKG_BUILD_DIR)/src/tools/wg $(1)/usr/bin/
$(INSTALL_BIN) ./files/wireguard_watchdog $(1)/usr/bin/
$(INSTALL_DIR) $(1)/lib/netifd/proto/
$(INSTALL_BIN) ./files/wireguard.sh $(1)/lib/netifd/proto/
endef

View file

@ -0,0 +1,60 @@
#!/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=$2
local public_key
local endpoint_host
local endpoint_port
local persistent_keepalive
local last_handshake
local idle_seconds
config_get public_key "${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