#!/usr/bin/perl -w
#
# GEL2-SW8 Switch Stats 0.1 - switch_stats.pl [2010-01-16]
# Copyright (C) 2010 Damian Pasternok <my_forename at pasternok.org>
# This code is free software under the GPLv3+.
# For more information see <http://gnu.org/licenses/gpl.html>.
#
# Requirements: RRDtool 1.3.x; Perl: Math::Round, RRDs

# configuration
$ipaddr="192.168.1.210";		# switch IP address
$graphname="switch_stats";		# name of graph
$tmpfile="/tmp/$graphname.tmp";		# temporary file that stores previous values read over SNMP
$workdir="/var/www/switch_stats";	# work directory in which all data could be stored
$graphdir="$workdir/img";		# chart images dir
$rrddir="$workdir/rrd";			# rrd database dir
$devname="Repotec RP-G0802L";		# switch description
# port descriptions, e.g. device names
@portdesc = ("port 1", "port 2", "port 2", "port 3", "port 3", "port 6", "port 7", "port 8");

# code - do not change anything below here
use Math::Round;
use RRDs;

# get snmp values and return them as an array
sub get_snmp {
    my $inout_traffic = `snmpwalk -v 1 -c public $ipaddr IF-MIB::ifInOctets | awk '{ print \$4 }'`;
    $inout_traffic .= `snmpwalk -v 1 -c public $ipaddr IF-MIB::ifOutOctets | awk '{ print \$4 }'`;

    return split(" ", $inout_traffic);
}

# write array of values into tmpfile as a single string separated by comas
sub update_tmp {
    open TMPFILE, ">", $tmpfile or die $!;
    print TMPFILE join(",", @_);
    close TMPFILE;
}

# compare snmp values with old from tmpfile; update tmpfile; return the difference between them
sub get_values {
    my @inout_traffic = &get_snmp;
    if(! -e $tmpfile) {
    	&update_tmp(@inout_traffic);
    }
    open TMPFILE, "<", $tmpfile or die $!;
    my @old_inout_traffic = split(",", <TMPFILE>);
    close TMPFILE;
    &update_tmp(@inout_traffic);

    my @data;
    for(my $i = 0; $i < @inout_traffic; $i++) {
	# if device was reseted count from 0
	if($inout_traffic[$i] < $old_inout_traffic[$i]) {
	    # outgoing traffic has negative values
	    if($i >= @inout_traffic / 2) {
	    	# convert bytes into bits and divide by interval
	        push(@data, -$inout_traffic[$i] * 8 / $_[0]);
	    }
	    else {
	    	push(@data, $inout_traffic[$i] * 8 / $_[0]);
	    }
	}
	else {
	    if($i >= @inout_traffic / 2) {
	    	push(@data, round(-($inout_traffic[$i] - $old_inout_traffic[$i]) * 8 / $_[0]));
	    }
	    else {
	    	push(@data, round(($inout_traffic[$i] - $old_inout_traffic[$i]) * 8 / $_[0]));
	    }
	}
    }

    return @data;
}

# create new rrd database if doesn't exist
sub create_rrd {
    if(! -e "$rrddir/$graphname.rrd") {
	if(! -e $rrddir) {
	    mkdir $rrddir;
	}
	RRDs::create "$rrddir/$graphname.rrd", "-s $_[0]",
	"DS:in_port1:GAUGE:600:-28000000:28000000",
	"DS:in_port2:GAUGE:600:-28000000:28000000",
	"DS:in_port3:GAUGE:600:-28000000:28000000",
	"DS:in_port4:GAUGE:600:-28000000:28000000",
	"DS:in_port5:GAUGE:600:-28000000:28000000",
	"DS:in_port6:GAUGE:600:-28000000:28000000",
	"DS:in_port7:GAUGE:600:-28000000:28000000",
	"DS:in_port8:GAUGE:600:-28000000:28000000",
	"DS:out_port1:GAUGE:600:-28000000:28000000",
	"DS:out_port2:GAUGE:600:-28000000:28000000",
	"DS:out_port3:GAUGE:600:-28000000:28000000",
	"DS:out_port4:GAUGE:600:-28000000:28000000",
	"DS:out_port5:GAUGE:600:-28000000:28000000",
	"DS:out_port6:GAUGE:600:-28000000:28000000",
	"DS:out_port7:GAUGE:600:-28000000:28000000",
	"DS:out_port8:GAUGE:600:-28000000:28000000",
	"RRA:AVERAGE:0.5:1:576",
	"RRA:AVERAGE:0.5:6:672",
	"RRA:AVERAGE:0.5:24:732",
	"RRA:AVERAGE:0.5:144:1460";

	if ($ERROR = RRDs::error) {
	    print "$graphname: unable to generate graph: $ERROR\n";
	}
    }
}

# update rrd database
sub update_rrd {
    for (my $i = 0; $i < @portdesc; $i++) {
	print "$portdesc[$i]\r\t\tRX: $_[$i]\r\t\t\t\t\tTX: $_[$i+8]\n";
    }
    RRDs::update "$rrddir/$graphname.rrd",
    "-t", "in_port1:in_port2:in_port3:in_port4:in_port5:in_port6:in_port7:in_port8:out_port1:out_port2:out_port3:out_port4:out_port5:out_port6:out_port7:out_port8", "N:$_[0]:$_[1]:$_[2]:$_[3]:$_[4]:$_[5]:$_[6]:$_[7]:$_[8]:$_[9]:$_[10]:$_[11]:$_[12]:$_[13]:$_[14]:$_[15]";

    if ($ERROR = RRDs::error) {
	print "$graphname: unable to generate graph: $ERROR\n";
    }
}

# create png graph
sub create_graph {
    if(! -e $graphdir) {
        mkdir $graphdir;
    }
    RRDs::graph "$graphdir/$graphname-$_[0].png",
    "-z",
    "-s -1$_[0]",
    "-t $devname Switch Traffic (+ RX  - TX)",
    "-h", "136", "-w", "517",
    "-a", "PNG",
    "-v bits per second",
    "-c", "BACK#000000",
    "-c", "CANVAS#000000",
    "-c", "FONT#f0f0f0",
    "-n", "DEFAULT:0:glispbold",
    "DEF:in_port1=$rrddir/$graphname.rrd:in_port1:AVERAGE",
    "DEF:in_port2=$rrddir/$graphname.rrd:in_port2:AVERAGE",
    "DEF:in_port3=$rrddir/$graphname.rrd:in_port3:AVERAGE",
    "DEF:in_port4=$rrddir/$graphname.rrd:in_port4:AVERAGE",
    "DEF:in_port5=$rrddir/$graphname.rrd:in_port5:AVERAGE",
    "DEF:in_port6=$rrddir/$graphname.rrd:in_port6:AVERAGE",
    "DEF:in_port7=$rrddir/$graphname.rrd:in_port7:AVERAGE",
    "DEF:in_port8=$rrddir/$graphname.rrd:in_port8:AVERAGE",
    "DEF:out_port1=$rrddir/$graphname.rrd:out_port1:AVERAGE",
    "DEF:out_port2=$rrddir/$graphname.rrd:out_port2:AVERAGE",
    "DEF:out_port3=$rrddir/$graphname.rrd:out_port3:AVERAGE",
    "DEF:out_port4=$rrddir/$graphname.rrd:out_port4:AVERAGE",
    "DEF:out_port5=$rrddir/$graphname.rrd:out_port5:AVERAGE",
    "DEF:out_port6=$rrddir/$graphname.rrd:out_port6:AVERAGE",
    "DEF:out_port7=$rrddir/$graphname.rrd:out_port7:AVERAGE",
    "DEF:out_port8=$rrddir/$graphname.rrd:out_port8:AVERAGE",

    "AREA:in_port1#f0f0f0:$_[1]",
    "AREA:in_port2#a0f0f0:$_[2]:STACK",
    "AREA:in_port3#00d0f0:$_[3]:STACK",
    "AREA:in_port4#00a0f0:$_[4]:STACK",
    "AREA:in_port5#0070f0:$_[5]:STACK",
    "AREA:in_port6#0040f0:$_[6]:STACK",
    "AREA:in_port7#0010f0:$_[7]:STACK",
    "AREA:in_port8#0000c0:$_[8]:STACK",
    "AREA:out_port1#f0f0f0",
    "AREA:out_port2#a0f0f0::STACK",
    "AREA:out_port3#00d0f0::STACK",
    "AREA:out_port4#00a0f0::STACK",
    "AREA:out_port5#0070f0::STACK",
    "AREA:out_port6#0040f0::STACK",
    "AREA:out_port7#0010f0::STACK",
    "AREA:out_port8#0000c0::STACK";

    if ($ERROR = RRDs::error) {
	print "$graphname: unable to generate graph: $ERROR\n";
    }
}

&create_rrd(300);
&update_rrd(get_values(300));
&create_graph("day", @portdesc);
&create_graph("week", @portdesc);
&create_graph("month", @portdesc);
&create_graph("year", @portdesc);