vpncwatch (shell version)

vpncwatch

#!/bin/sh

log() {
  logger -t vpncwatch $@
}

SH_PID="/var/run/vpncwatch.pid"
VPNC="/usr/sbin/vpnc"
VPNC_OPTS=""
VPNC_PID="/var/run/vpnc/pid"
VPNC_LOG="/var/log/vpncwatch"
PROBE_IP="199.59.148.10"

# single instance
if kill -0 $(cat $SH_PID 2>/dev/null) 2>/dev/null; then
  log "only one instance can be running"
  exit
fi

# fork to background daemon
if [ -z "$_BACKGROUNDED" ]; then
  _BACKGROUNDED=1 nohup $0 $@ >> $VPNC_LOG 2>&1 &
  exit
fi

echo $$ > $SH_PID

start_vpnc() {
  $VPNC $VPNC_OPTS
  sleep 1s # give some time to connect
}

stop_vpnc() {
  killall -w vpnc 2>/dev/null
}

sig_handler() {
  log "exit"
  stop_vpnc
  rm $SH_PID 2>/dev/null
  exit
}

# kill vpnc properly when being terminated
trap sig_handler exit INT TERM

while true; do
  # check /opt has been mount
  if [ -f $VPNC ]; then
    # check vpnc is running
    if kill -0 $(cat $VPNC_PID 2>/dev/null) 2>/dev/null; then
      # check vpnc connection
      if ping -q -W 2 -c 5 $PROBE_IP > /dev/null; then
        :
      else
        log "vpnc died, restarting"
        stop_vpnc
        start_vpnc
      fi
    else
      log "starting vpnc"
      start_vpnc
    fi
  fi
done

Should be run in a cronjob or any other than ssh, since shell in tomato will exit completely including all nohup process.