OpenWrt passwall service watchdog. Auto restart service when tcp node dns resolve ip changed.

passwall_watchdog.sh

#!/bin/sh
# Run this script from cron every 10 minutes:
# echo '*/10 * * * * /path/to/passwall_watchdog.sh' >> /etc/crontabs/root

enabled=$(uci get passwall.@global[0].enabled)
tcp_node=$(uci get passwall.@global[0].tcp_node)
address=$(uci get passwall.$tcp_node.address)
previous_ip=$(uci get passwall.$tcp_node.ip 2>/dev/null)
current_ip=$(resolveip $address)

if [ -z "$current_ip" ]; then
  logger -t "passwall_watchdog" "resolveip failed, skip."
  exit 0
fi

if [ "$previous_ip" = "$current_ip" ]; then
  exit 0
else
  uci set passwall.$tcp_node.ip=$current_ip

  if [ "$enabled" = "1" ] && [ -n "$previous_ip" ]; then
    logger -t "passwall_watchdog" "$address: $previous_ip -> $current_ip, restarting service..."
    service passwall restart
  fi
fi

exit 0