source: npl/internetserver/libreswan_conf/root/sbin/syn3-ipseccheck

#!/bin/bash
#DatuX vpn monitoring script (C)2007 DatuX/Syn-3


if [ "$1" ]; then
        MONS="/etc/ipsec.d/tunnels/$1.mon"
else
        MONS="/etc/ipsec.d/tunnels/*.mon"
fi

for MON in $MONS; do
        IP=
        SRC=
        DISABLED=1
        source "$MON" 2>/dev/null
        TUN=`basename "$MON"|sed 's/.mon$//'`
        FACILITY="ipsec_$TUN"

        if grep "auto=ignore" "/etc/ipsec.d/tunnels/$TUN.conf" &>/dev/null || 
            [ "$DISABLED" = "1" ] ||
            [ ! $IP ] 
        then
            syn3-state "$FACILITY" DELETE  
            continue;
        fi

        echo "$TUN: Checking tunnel $IP..."
        #sleep 1 second, otherwise ping and fping hang 30 seconds for some reason?
        sleep 1

        if [ "$SRC" != "" ]; then
                PING_CMD="fping -S $SRC -r 20 -B 1 $IP";
        else
                PING_CMD="fping -r 20 -B 1 $IP";
        fi
        

        (sleep 10;killall -9 fping )&  #route mode is ehold, causing fping to hang
        KILLER_PID=$!
        if ! $PING_CMD ; then
                echo "$TUN: Down! Restarting tunnel!"
                ipsec auto --delete $TUN
                ipsec auto --add $TUN
                ipsec auto --asynchronous --up $TUN 
                syn3-state "$FACILITY" CAUTION "No ping reply to $IP@$TUN (from $SRC) Reconnecting..."
        else
                echo "$TUN: OK"
                syn3-state "$FACILITY" OK  "Ping to $IP@$TUN (from $SRC) is ok."
        fi
        kill -9 $KILLER_PID &>/dev/null #kill the killer
        
done 

exit 0