check_ax_clients

#!/usr/bin/perl -w

# Monitor clients on Apple Airport Extreme an Express 
# Requires AIRPORT-BASESTATION-3-MIB in any default SNMP MIB location
#
# Written by Darko Krizic <darko@krizic.net>

use strict;
use Data::Dumper;

my $ax = shift;

unless ( defined $ax ) {
	print "Usage: $0 <airport>\n";
	exit 2;
}

my %mac;
open(SNMP,"snmpwalk -c public -v 2c -m AIRPORT-BASESTATION-3-MIB $ax SNMPv2-SMI::enterprises.apple.airport | grep wirelessPhysAddress |");
while(my $line = <SNMP>) {
	chomp $line;
	my ($null,$mac) = split(" = STRING: ", $line);
	$mac = lc $mac;
	$mac =~ s/"//g;
	$mac{$mac} = {};
}
close(SNMP);

#my %arp;
open(ARP,"/usr/sbin/arp |");
<ARP>;
while(my $line = <ARP>) {
	chomp $line;
	my ($name,$null,$mac,$null2) = split(/ +/, $line );
	if( $name =~ m/[A-Za-z]/g ) {
		$name =~ s/\..+//g;
	}
	if( defined $mac{$mac} ) {
		$mac{$mac}->{'name'} = $name;
	}
}
close(ARP);

foreach( keys %mac ) {
	unless( defined $mac{$_}->{'name'} ) {
		$mac{$_}->{'name'} = '-';
	}
}

open(WHITELIST,"/usr/local/etc/whitelist.arp");
while(my $line = <WHITELIST>) {
	chomp $line;
	next if $line =~ m/^$/;
	next if $line =~ m/^#/;
	my ($mac,$name) = split( "=", $line );
	if( defined $mac{$mac} ) {
		$mac{$mac}->{'whitelist'} = 1;
		$mac{$mac}->{'name'} = $name;
	}
}
close(WHITELIST);

my $exit = 0;
my @unknown;
my @known;

#print Dumper(\%mac);

foreach( keys %mac ) {
	my $name = $mac{$_}->{'name'};
	if( defined $mac{$_}->{'whitelist'} ) {
		if( $name ne '-' ) {
			push @known,$name;
		} else {
			push @known,$_;
		}
	} else {
		push @unknown,"$name=$_";
	}
}

if( scalar @unknown > 0 ) {
	$exit = 1;
}

my $kcount = scalar @known;
my $ucount = scalar @unknown;
my $known = join(", ",@known);
my $unknown = join(", ",@unknown);
my $perf = "'known'=$kcount 'unknown'=$ucount;1;5";
if( $exit == 0 ) {
	print "OK: $known | $perf\n";
	exit 0;
} else {
	print "WARNING: Unkown clients $unknown - known $known | $perf\n";
	exit 1;
}