#!/bin/bash

#Netstat connections monitoring

METRIC="$1"

if [[ -z "$1" ]]; then
    echo "Please enter metric"
    exit 1
fi

CACHETTL="55" # Время действия кеша в секундах (чуть меньше чем период опроса элементов)
CACHE="/tmp/netstat-status-`echo netstat| md5sum | cut -d" " -f1`.cache"

if [ -s "$CACHE" ]; then
    TIMECACHE=`stat -c"%Z" "$CACHE"`
else
    TIMECACHE=0
fi

TIMENOW=`date '+%s'`

if [ "$(($TIMENOW - $TIMECACHE))" -gt "$CACHETTL" ]; then
	netstat -tan|grep -e ':80\|:443' > $CACHE || exit 1
fi

case $METRIC in
    'established')
        cat $CACHE | grep "ESTABLISHED" | wc -l
        ;;            
    'time_wait')
        cat $CACHE | grep "TIME_WAIT" | wc -l
        ;;
    *)   
        echo "Not selected metric"
        exit 0
        ;;
esac