#!/usr/bin/perl

=pod

=encoding UTF-8

=head1 NAME

nomadix_users_ - SNMP wildcard plugin to monitor the number of users of Nomadix Enterprise WiFi devices

=head1 APPLICABLE SYSTEMS

The plugin was written specifically for OSL's nomadix equipment.  It
uses SNMP to monitor the devices.  Any devices that support one or
more of these OIDs:

  .1.3.6.1.4.1.3309.1.1.2.18.1.1.8 from USG-II
  .1.3.6.1.4.1.3309.1.4.2.18.1.1.8 for AG5000
  .1.3.6.1.4.1.3309.1.5.2.18.1.1.8 for AG3000

should be able to get their users counted.

=head1 CONFIGURATION

Configuration is done by editing the plugin.

=head1 BUGS

Should support configuration via the environment

Should be rewritten as a autoconfigurable snmp__users (or some such
name, not sure how specific the OIDs it presents are) plugin using the
Plugin::SNMP module.

=head1 AUTHORS

Copyright (C) 2006-2009 Espen Braastad, Linpro AS for OSL

Copyright (C) 2007 Erik Inge Bolsø, Linpro AS for OSL

=head1 LICENSE

GPLv2

SPDX-License-Identifier: GPL-2.0-only

=head1 MAGIC MARKERS

None.  No autoconfiguration is supported and indeed the plugin must be
configured by editing it.

=cut

use strict;
use Net::SNMP;

my $snmpwalk="/usr/bin/snmpwalk";       # Path to the snmpwalk executable
my $timeout=1;                          # snmp timeout
my $debug=0;                            # Enable/disable debugging
my $community="public";
my $oid_users=".1.3.6.1.4.1.3309.1.1.2.18.1.1.8"; #USG-II
my $oid_users_2=".1.3.6.1.4.1.3309.1.4.2.18.1.1.8"; #AG5000
my $oid_users_3=".1.3.6.1.4.1.3309.1.5.2.18.1.1.8"; #AG3000
my $oid_name=".1.3.6.1.2.1.1.5.0";

my $target=`basename $0 | sed 's/^nomadix_users_//g'`;
exit 2 unless defined $target;
$target=~s/\_/\./g;

chomp($target);

my $status=2;

if ($ARGV[0] and $ARGV[0] eq "autoconf")
{
        if(-x ${snmpwalk}){
                my ${test}=`${snmpwalk} -v 1 -c ${community} -t ${timeout} ${target} ${oid_users} -Cp -OQv 2>/dev/null`;
                if($?==0){
                        print "yes\n";
                        exit 0;
                }
                exit 1;
        }
        exit 1;
}

if($ARGV[0] and $ARGV[0] eq "config") {
        my ${sysname}=`${snmpwalk} -v 1 -c ${community} -t ${timeout} ${target} ${oid_name} -OQv 2>/dev/null`;
        chomp(${sysname});
        print "graph_title Users on " . ${sysname} . " (" . ${target} . ")\n";
        print "graph_args --base 1000\n";
        print "graph_vlabel Active users\n";
        print "graph_category Nomadix\n";
        print 'graph_info This graph shows the amount of users in AAA state "Valid" connected to ' . ${target} . ".\n";
        print "valid.label Valid users\n";
        print "valid.type GAUGE\n";
        exit 0;
}

# Checking if snmpwalk is found and executable
if(! -x ${snmpwalk}){
        ${status}=2;
        print STDERR "Error: " . ${snmpwalk} . " not found.\n";
        if(${debug}){
                print "Exit code: " . ${status} . "\n";
        }
        exit ${status};
}
# Let's see if we are able to talk to the SNMP host
my @{users}=split("\n",`${snmpwalk} -v 1 -c ${community} -t ${timeout} ${target} ${oid_users} -Cp -OQv 2>/dev/null`);

my ${snmpexit}=$?;
if(${snmpexit}!=0){
        ${status}=2;
        print STDERR "Error: Unable to connect to ${target}. Exit code was " . ${snmpexit} . ".\n";
        if(${debug}){
                print "Exit code: " . ${status} . "\n";
        }
        exit ${status};
}

# Count users, both valid and otherwise
my ${number_of_users}=(split(" ",${users[-1]}))[-1];

if (${number_of_users} == 0)
{
        @{users}=split("\n",`${snmpwalk} -v 1 -c ${community} -t ${timeout} ${target} ${oid_users_2} -Cp -OQv 2>/dev/null`);
}

${number_of_users}=(split(" ",${users[-1]}))[-1];

if (${number_of_users} == 0)
{
        @{users}=split("\n",`${snmpwalk} -v 1 -c ${community} -t ${timeout} ${target} ${oid_users_3} -Cp -OQv 2>/dev/null`);
}

${number_of_users}=(split(" ",${users[-1]}))[-1];

if(${debug}){
        print "Total number of users found: " . ${number_of_users} . "\n";
}
# Checking if the number of users is a numeric value
if (${number_of_users} =~ /^-?\d/){
        # Loop through users, extract authentication state
        my ${valid_users}=0;
        for(my ${i}=1 ; ${i}<=${number_of_users} ; ${i}++){
                my ${state}=${users[${i}-1]};
                if(${state} =~ /Valid/){
                        ${valid_users}+=1;
                }
                if(${debug}){
                        print "User in state " . ${state} . "\n";
                }
        }

        # Write human readable output
        print "valid.value " . ${valid_users} . "\n";
        if(${debug}){
                print "Exit code: " . ${status} . "\n";
        }
        ${status}=0;
        exit ${status};
} else {
        ${status}=2;
        print STDERR "Error: The number of users found is not a numerical value. Unable to monitor correctly.\n";
        if(${debug}){
                print "Exit code: " . ${status} . "\n";
        }
        exit ${status};
}

# Obs!
print STDERR "This is not supposed to happen. Debugging is needed!\n";
${status}=2;
if(${debug}){
        print "Exit code: " . ${status} . "\n";
}
exit ${status};