#!/bin/sh


cd /path/to || exit 1


interface=tl0

rrd=traffic.rrd

graph=traffic.png


export PATH="$PATH:/usr/local/bin"


if [ ! -f "$rrd" ]
then
	rrdtool create "$rrd" \
		--step 300 \
		\
		DS:inbytes:COUNTER:600:U:U \
		DS:outbytes:COUNTER:600:U:U \
		\
		RRA:AVERAGE:0.5:1:600 \
		RRA:AVERAGE:0.5:6:700 \
		RRA:AVERAGE:0.5:24:775 \
		RRA:AVERAGE:0.5:288:797 \
		\
		RRA:MAX:0.5:1:600 \
		RRA:MAX:0.5:6:700 \
		RRA:MAX:0.5:24:775 \
		RRA:MAX:0.5:288:797 \
		\
		|| exit 1
fi


bytes=`netstat -bn -f link -I "$interface" | awk -v "i=$interface" '{if ($1 == i) print $7":"$10}'`


rrdtool update "$rrd" "N:$bytes" || exit 1


rrdtool graph "$graph" \
	--imgformat PNG \
	\
	--width 500 \
	--height 150 \
	\
	--start -1d \
	--title "Network traffic bit/s" \
	\
	--base 1000 \
	\
	--slope-mode \
	--interlaced \
	--alt-y-grid \
	\
	--lazy \
	\
	"DEF:inbytes=$rrd:inbytes:AVERAGE" \
	"DEF:outbytes=$rrd:outbytes:AVERAGE" \
	\
	'CDEF:inbits=inbytes,8,*' \
	'CDEF:outbits=outbytes,8,*' \
	\
	'CDEF:outbits_neg=outbits,-1,*' \
	\
	'COMMENT: \n' \
	'COMMENT:                 Max         Avg         Last\n' \
	'COMMENT: \n' \
	\
	'AREA:inbits#74D2F1:incoming' \
	'GPRINT:inbits:MAX:%8.2lf %s' \
	'GPRINT:inbits:AVERAGE:%8.2lf %s' \
	'GPRINT:inbits:LAST:%8.2lf %sbit/s\n' \
	\
	'LINE1:inbits#45709E:' \
	\
	'AREA:outbits_neg#6DF8BE:outgoing' \
	'GPRINT:outbits:MAX:%8.2lf %s' \
	'GPRINT:outbits:AVERAGE:%8.2lf %s' \
	'GPRINT:outbits:LAST:%8.2lf %sbit/s\n' \
	\
	'LINE1:outbits_neg#4CAC84:' \
	\
	'HRULE:0#000000' \
	\
	"COMMENT:                                                            `date '+%Y-%m-%d %H\:%M\:%S'`" \
	\
	> /dev/null