ddwrt-ovpn-server-watchdog.sh

#!/bin/sh
#DEBUG=; set -x # uncomment/comment to enable/disable debug mode

#          name: ddwrt-ovpn-server-watchdog.sh
#       version: 1.2.0, 02-oct-2024, by eibgrad
#       purpose: (re)start failed/stopped openvpn server
#   script type: startup (autostart)
#  installation:
#    1. enable jffs2 (administration->jffs2)
#    2. enable syslogd (services->services->system log)
#    3. use shell (telnet/ssh) to execute one of the following commands:
#         curl -kLs bit.ly/ddwrt-installer|tr -d '\r'|sh -s -- 4QyiANWh startup
#       or
#         wget -qO - bit.ly/ddwrt-installer|tr -d '\r'|sh -s -- 4QyiANWh startup
#    4. (optional): use vi editor to modify options:
#         vi /jffs/etc/config/ddwrt-ovpn-server-watchdog.startup
#    5. reboot
(
# ------------------------------ BEGIN OPTIONS ------------------------------- #

# time (in secs) between checks for failed/stopped openvpn server
CHECK_INTERVAL=60

# ------------------------------- END OPTIONS -------------------------------- #

# ---------------------- DO NOT CHANGE BELOW THIS LINE ----------------------- #

LOCK="/tmp/$(basename $0).lock"
OVPN_CONF='/tmp/openvpn/openvpn.conf'

# reject additional instances
mkdir $LOCK &>/dev/null || exit 0

# catch unexpected exit and cleanup
trap "rmdir $LOCK; exit 0" SIGHUP SIGINT SIGTERM

# wait for *reliable* internet connection
until ping -qc1 -W3 8.8.8.8 &>/dev/null; do sleep 10; done

while sleep $CHECK_INTERVAL; do
    # openvpn server must be enabled
    [ "$(nvram get openvpn_enable)" != '0' ] || continue

    # check for failed/stopped openvpn server
    [ "$(ps | awk '$0~v{print $1}' v="--config +$OVPN_CONF")" ] && continue

    # fall-through means failure; restart the openvpn server
    stopservice  openvpnserver && sleep 5
    startservice openvpnserver && sleep 5
    echo "info: openvpn server (re)started @ $(date)"
done

) 2>&1 | logger -t "$(basename $0) | grep -Eo '^.{0,23}')[$$]" &