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# -*- mode: perl -*-
#
# Copyright (C) 2004 Dagfinn Ilmari Mannsaaker
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; version 2 dated June,
# 1991.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
#
package Munin::Plugin::SNMP;
use Net::SNMP;
@ISA = qw(Net::SNMP);
# $Id: SNMP.pm.in 860 2005-03-29 20:32:59Z ilmari $
=head1 NAME
Munin::Plugin::SNMP - Net::SNMP subclass for Munin plugins
=head1 SYNOPSIS
The Munin::Plugin::SNMP module extends Net::SNMP with methods useful for
Munin plugins.
=head1 METHODS
=head2 session() - create new Munin::Plugin::SNMP object
($session, $error) = Munin::Plugin::SNMP->session();
This method overrides the Net::SNMP constructor to get the connection
info from the plugin name and/or environment. The hostname is taken from
the plugin symlink, which must be on the form
C<snmp_E<lt>hostnameE<gt>_E<lt>plugin_nameE<gt>[_args]>. The following
environment variables are consulted:
=over
=item host
Used as the hostname to connect to (and output from the plugin) if the
symlink does not contain a host name. If neither are set, an error is
returned.
=item port
The port to connect to. Default 161.
=item community
The community name. Default public.
=item version
The SNMP version to use for the connection. Default auto.
=back
=cut
sub session {
my $class = shift;
my $host = $ENV{host} || undef;
my $port = $ENV{port} || 161;
my $community = $ENV{community} || 'public';
my $version = $ENV{version} || undef;
if ($0 =~ /^(?:.*\/)?snmp_([^_]+)_/) {
$host = $1;
if ($host =~ /^([^:]+):(\d+)$/) {
$host = $1;
$port = $2;
}
} elsif (!defined($host)) {
return unless wantarray; # Scalar or void context
return (undef, 'Couldn not find monitoring target.'); # Array context
}
return $class->SUPER::session(-hostname => $host,
-community => $community,
-port => $port,
($version ? (-version => $version) : ()));
}
=head2 get_hash() - retrieve a table as a hash of hashes
$result = $session->get_hash(
[-callback => sub {},] # non-blocking
[-delay => $seconds,] # non-blocking
[-contextengineid => $engine_id,] # v3
[-contextname => $name,] # v3
-baseoid => $oid,
-cols => \%columns
);
This method calls C<get_table()> with all the given arguments except
C<-cols>, and then transforms the data into a hash of hashes in the
following manner:
The keys of the main hash are the last element(s) of the OIDs, after
C<$oid> and the matching keys from C<%columns> are removed. The values
are hashes with keys corresponding to the values of C<%columns> hash and
values from the subtables corresonding to the keys of C<%columns>.
For this to work, all the keys of C<-cols> must have the same number of
elements.
Example:
$session->get_hash(
-baseoid => '1.3.6.1.2.1.2.2.1', # IF-MIB
-cols => {
1 => 'index',
2 => 'descr',
4 => 'mtu',
}
);
given the following SNMP table:
IF-MIB::ifIndex.1 = INTEGER: 1
IF-MIB::ifIndex.2 = INTEGER: 2
IF-MIB::ifDescr.1 = STRING: lo0
IF-MIB::ifDescr.2 = STRING: lna0
IF-MIB::ifType.1 = INTEGER: softwareLoopback(24)
IF-MIB::ifType.2 = INTEGER: ethernetCsmacd(6)
IF-MIB::ifMtu.1 = INTEGER: 32768
IF-MIB::ifMtu.2 = INTEGER: 1500
...
will return a hash like this:
'1' => {
'index' => '1',
'mtu' => '32768',
'descr' => 'lo0'
},
'2' => {
'index' => '2',
'descr' => 'lna0',
'mtu' => '1500'
}
=cut
sub get_hash {
my $self = shift;
my %args = @_;
my %ret;
my $base = $args{'-baseoid'};
my $cols = delete $args{'-cols'} or return;
my $table = $self->get_table(%args)
or return;
my $subtabs = join '|', keys %$cols;
my $re = qr/^\Q$base.\E($subtabs)\.(.*)/;
for my $key (keys %$table) {
$key =~ $re;
next unless defined($1 && $2);
$ret{$2}{$cols->{$1}} = $table->{$key};
}
return \%ret;
}
=head1 TODO
Lots.
=head1 BUGS
C<get_hash()> doesn't handle tables with sparse indices.
=back
=head1 SEE ALSO
L<Net::SNMP>
=head1 AUTHOR
Dagfinn Ilmari Mannsker E<lt>ilmari@linpro.noE<gt>
=head1 COPYRIGHT
Copyright (c) 2004 Dagfinn Ilmari Mannsker E<lt>ilmari@linpro.noE<gt>.
All rights reserved. This program is free software; you can redistribute
it and/or modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; version 2 dated June, 1991.
=cut
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