#!/usr/bin/perl -T

use warnings;
use strict;

$ENV{'PATH'} = '/bin:/usr/bin:/sbin:/usr/sbin';
delete @ENV{'IFS', 'CDPATH', 'ENV', 'BASH_ENV'};

# define nagios status codes
my %nagios = (
    'ok' => ["OK", 0],
    'warn' => ["WARNING", 1],
    'crit' => ["CRITICAL", 2],
    'unknown' => ["UNKNOWN", 3]
);

# Print nagios compatible status message and terminat script
# with apropiate return code.
#
# parameter: type of message
sub msg ($@) {
    my $type = shift;
    my ($msg, $exit) = @{$nagios{$type}};

    print $msg, " - ", @_, "\n";
    exit $exit;
}

sub get_if_status (@) {
    my (@up, @down, @error);

    while (@_) {
        my $if = shift @_;
        next unless ($if =~ m/^([-\w]+)$/);
        $if = $1;

        my $pid = open(IFCONFIG, "-|");
        msg('crit', "fork: $!") unless defined $pid;

        if ($pid == 0) {
            # child
            open(STDERR, ">", "/dev/null");
            exec("ifconfig", $if)
        }

        while (<IFCONFIG>) {
            if ($_ =~ m/^([-a-v0-9]+): flags=([0-9]+)</) {
                if ($2 & 1) {
                    push(@up, $1);
                }
                else {
                    push (@down, $if) if $1 eq $if;
                }
            }
        }

        close(IFCONFIG) or push(@error, $if);
    }

    return (\@up, \@down, \@error);
}

sub get_if_stats ($) {
    my $if = shift;
    my $stats = {};

    open(PFCTL, "-|", "pfctl", "-vvsI", "-i", $if);
    while (<PFCTL>) {
        if ($_ =~ m{In4/Pass.*Bytes: ([0-9]+)}) {
            $stats->{'in4'} = $1;
        }
        elsif ($_ =~ m{Out4/Pass.*Bytes: ([0-9]+)}) {
            $stats->{'out4'} = $1;
        }
        elsif ($_ =~ m{In6/Pass.*Bytes: ([0-9]+)}) {
            $stats->{'in6'} = $1;
        }
        elsif ($_ =~ m{Out6/Pass.*Bytes: ([0-9]+)}) {
            $stats->{'out6'} = $1;
        }
    }
    close(PFCTL);

    return $stats;
}

sub print_stats ($) {
    my $stats = shift;
    my ($count, $perfdata);

    $count = keys %$stats;
    $perfdata = "";
    for my $if (keys %$stats) {
        for (qw( in4 out4 in6 out6 )) {
            $perfdata = "$perfdata $if-$_=$stats->{$if}->{$_};";
        }
    }

    msg('ok', "$count interfaces |$perfdata");
}


my ($up, $down, $error) = get_if_status(@ARGV);

if (@$error) {
    $error = join ", ", @$error;
    msg('crit', "Some interfaces does not exists: $error");
}

if (@$down) {
    $down = join ", ", @$down;
    msg('warn', "Some interfaces are down: $down");
}

my $stats = {};
for my $if (@$up) {
    $stats->{$if} = get_if_stats($if);
}

print_stats($stats);