#!/usr/bin/perl -w

=head1 NAME

openvpn_multi - Plugin for monitoring OpenVPN users traffic

=head1 CONFIGURATION

  [openvpn_multi]
    user root
    env.statusfile /var/log/openvpn.status

=head1 AUTHOR

Copyright 2013 Pierre Schweitzer <pierre@reactos.org>

=head1 LICENSE

GNU GPL v2 or any later version

=head1 MAGIC MARKERS

 #%# family=auto
 #%# capabilities=autoconf

=cut

use strict;
use Munin::Common::Defaults;
use Munin::Plugin;

my $statusfile = ($ENV{'statusfile'} || '/var/log/openvpn.status');

sub config {
	open FILE, $statusfile or die $!;

	print "multigraph openvpn_users\n";
	print "graph_title OpenVPN traffic\n";
	print "graph_args --base 1024 --lower-limit 0\n";
	print "graph_vlabel Bytes Out (-) / In (+) per \${graph_period}\n";
	print "graph_category network\n";
	print "in.label recv\n";
	print "in.type DERIVE\n";
	print "in.min 0\n";
	print "in.graph no\n";
	print "in.cdef in,1,*\n";
	print "out.label Bps\n";
	print "out.type DERIVE\n";
	print "out.min 0\n";
	print "out.negative in\n";
	print "out.cdef out,1,*\n";

	while (<FILE>) {
		next if ($_ =~ /CLIENT LIST/ || $_ =~ /Updated/ || $_ =~ /Common Name/ || $_ =~ /^UNDEF,/);
		last if ($_ =~ /ROUTING TABLE/);

		# client,IP:port,in,out,D M N hour Y
		my @values = split(',', $_);
		my $name = $values[0];
		my $fieldname = clean_fieldname($name);

		print "multigraph openvpn_users.$fieldname\n";
		print "graph_title OpenVPN traffic for $name\n";
		print "graph_args --base 1024 --lower-limit 0\n";
		print "graph_vlabel Bytes Out (-) / In (+) per \${graph_period}\n";
		print "graph_category network\n";
		print "in.label recv\n";
		print "in.type DERIVE\n";
		print "in.min 0\n";
		print "in.graph no\n";
		print "in.cdef in,1,*\n";
		print "out.label Bps\n";
		print "out.type DERIVE\n";
		print "out.min 0\n";
		print "out.negative in\n";
		print "out.cdef out,1,*\n";
	}
	close FILE;

	exit 0;
}

sub autoconf {
	if (-e $statusfile) {
		print "yes\n";
	} else {
		print "no\n";
	}
	exit 0;
}

sub report {
	my %in;
	my %out;
	my $tot_in = 0;
	my $tot_out = 0;

	my %previous_state = restore_state();
	my %new_state;

	open FILE, $statusfile or die $!;
	while (<FILE>) {
		next if ($_ =~ /CLIENT LIST/ || $_ =~ /Updated/ || $_ =~ /Common Name/ || $_ =~ /^UNDEF,/);
		last if ($_ =~ /ROUTING TABLE/);

		# client,IP:port,in,out,D M N hour Y
		my @values = split(',', $_);
		my $name = $values[0];

		my $in = 0;
		my $out = 0;
		if (exists $previous_state{$name."_in"} && exists $previous_state{$name."_out"}) {
			my $old_in = $previous_state{$name."_in"};
			my $old_out = $previous_state{$name."_out"};
			if ($old_in <= $values[2] && $old_out <= $values[3]) {
				$in = $values[2] - $old_in;
				$out = $values[3] - $old_out;
			}
		}

		$in{$name} = $in;
		$out{$name} = $out;
		$tot_in += $in;
		$tot_out += $out;

		$new_state{$name."_in"} = $values[2];
		$new_state{$name."_out"} = $values[3];
	}
	close FILE;

	print "multigraph openvpn_users\n";
	if (exists $previous_state{"total.in"} && exists $previous_state{"total.out"}) {
		my $old_tot_in = $previous_state{"total.in"};
		my $old_tot_out = $previous_state{"total.out"};
		if ($old_tot_in <= $tot_in && $old_tot_out <= $tot_out) {
			print "in.value $tot_in\n";
			print "out.value $tot_out\n";
		} else {
			print "in.value 0\n";
			print "out.value 0\n";
		}
	}  else {
		print "in.value 0\n";
		print "out.value 0\n";
	}

	$new_state{"total.in"} = $tot_in;
	$new_state{"total.out"} = $tot_out;

	save_state(%new_state);

	for my $name (keys %in) {
		my $in = $in{$name};
		my $out = $out{$name};
		my $fieldname = clean_fieldname($name);

		print "multigraph openvpn_users.$fieldname\n";
		print "in.value $in\n";
		print "out.value $out\n";
	}

	exit 0;
}

if ($ARGV[0]) {
	my $arg = $ARGV[0];
	my %funcs = (
		config   => \&config,
		autoconf => \&autoconf,
	);

	if (exists $funcs{$arg}) {
		$funcs{$arg}->();
	} else {
		die "Unknown argument '$arg'\n";
	}
} else {
	report();
}