1#!/usr/local/bin/perl -w
2#%# family=auto
3#%# capabilities=autoconf
4#
5# Copyright (c) 2013 Philip Paeps
6# All rights reserved.
7#
8# Redistribution and use in source and binary forms, with or without
9# modification, are permitted provided that the following conditions
10# are met:
11# 1. Redistributions of source code must retain the above copyright
12#    notice, this list of conditions and the following disclaimer
13#    in this position and unchanged.
14# 2. Redistributions in binary form must reproduce the above copyright
15#    notice, this list of conditions and the following disclaimer in the
16#    documentation and/or other materials provided with the distribution.
17#
18# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28# SUCH DAMAGE.
29#
30
31#
32# Plugin to monitor NSD performance.
33# Contributed by: Philip Paeps <philip@paeps.cx>.
34# Heavily inspired by the unbound_munin_ script by
35# W.C.A. Wijgaards and the nsd3 script by J.T.Sage.
36#
37# Usage: nsd_FUNCTION
38#
39# Available functions:
40#	by_type - incoming queries by type
41#	by_rcode - answers by rcode
42#	hits - base volume
43#
44# Example configuration:
45#
46#   [nsd_*]
47#   user bind
48#   env.logdir /var/log
49#   env.logfile nsd.log
50#
51#   [nsd_by_type]
52#   env.stats = A=A AAAA=AAAA MX=MX PTR=PTR TYPE252=AXFR SOA=SOA
53#
54# The stats line is an optional space-separated string of VALUE=Caption
55# pairs of query types to pick out of the NSTATS returned by NSD.  Replace
56# spaces in a caption value by _.
57#
58use strict;
59use Munin::Plugin;
60use POSIX;
61
62my $LOGDIR = $ENV{'logdir'} || '/var/log';
63my $LOGFILE = $ENV{'logfile'} || 'nsd.log';
64my $logfile = "$LOGDIR/$LOGFILE";
65my $pidfile = $ENV{'pidfile'} || '/var/run/nsd/nsd.pid';
66
67sub signal_nsd {
68	open(my $P, "< $pidfile") || die "Couldn't open pidfile: $!\n";
69	my $pid = <$P>;
70	close($P);
71
72	chomp $pid;
73	kill USR1 => $pid or die "Couldn't signal NSD: $!\n";
74
75	# Give the daemon a chance to write statistics.
76	sleep(0.5);
77}
78
79sub read_logfile($) {
80	my $stats = shift;
81	my $pos = undef;
82
83	($pos) = restore_state();
84	$pos = 0 unless defined($pos);
85	my ($L, $rotated) = tail_open($logfile, $pos);
86
87	my $last = 0;
88	while (<$L>) {
89		chomp $_;
90		if (/([NX]STATS) (\d+)/) {
91			$last = $2;
92			push @$stats, {
93				'type' => $1, 'when' => $2,
94				'values' => { $_ =~ m/(\S+)=(\d+)/g },
95			};
96		}
97	}
98	$pos = tail_close($L);
99	save_state($pos);
100
101	return $last;
102}
103
104sub get_values($) {
105	my $values = shift;
106
107	my @stats = ();
108	my $last = read_logfile(\@stats);
109
110	# If the values found in the logfile are older than three minutes,
111	# signal NSD to print fresh ones, and read them again.
112	my $now = time;
113	if ($now - $last > 3 * 60) {
114		signal_nsd();
115		read_logfile(\@stats);
116	}
117
118	# @stats is an array of the last lines found in the logfile.  Hopefully,
119	# the last two lines will be NSTATS and XSTATS.  If not, we need to keep
120	# looking.
121	foreach (keys %$values) {
122		foreach my $stat (reverse(@stats)) {
123			$values->{$_} = $stat->{'values'}{$_} if ($stat->{'values'}{$_});
124		}
125	}
126
127	return \@stats;
128}
129
130# Base volume
131sub hits($) {
132	my $function = shift;
133	my %captions = ();
134
135	%captions = (
136		'RR' => 'UDP queries dropped',
137		'SAns' => 'UDP queries answered',
138		'RTCP' => 'TCP connections',
139		'SErr' => 'Transmit errors',
140	);
141
142	# Print graph configuration.
143	if ($function and $function eq "config") {
144		print "graph_title NSD DNS traffic\n";
145		print "graph_args --base 1000 -l 0\n";
146		print "graph_vlabel queries / second\n";
147		print "graph_category dns\n";
148		foreach my $caption (keys %captions) {
149			my $label = $captions{$caption};
150			$label =~ s/_/ /;
151			print lc($caption) . ".label $label\n";
152			print lc($caption) . ".type DERIVE\n";
153			print lc($caption) . ".min 0\n";
154		}
155		print "graph_info Base volume\n";
156		exit 0;
157	}
158
159	my %values = map { $_ => 0 } keys %captions;
160	get_values(\%values);
161	foreach (keys %values) {
162		print lc($_) . ".value $values{$_}\n";
163	}
164
165	exit 0;
166}
167
168# DNS queries by type
169sub by_type($$) {
170	my ($function, $stats) = @_;
171
172	# Sensible default set of statistics.
173	if (! $stats) {
174		$stats = "A=A AAAA=AAAA MX=MX PTR=PTR TYPE252=AXFR SOA=SOA " .
175		    "TXT=TXT DNSKEY=DNSKEY NS=NS SPF=SPF";
176	}
177
178	my %captions = map { split /=/ } split / /, $stats;
179
180	# Print graph configuration.
181	if ($function and $function eq "config") {
182		print "graph_title NSD DNS queries by type\n";
183		print "graph_args --base 1000 -l 0\n";
184		print "graph_vlabel queries / second\n";
185		print "graph_category dns\n";
186		foreach my $caption (keys %captions) {
187			my $label = $captions{$caption};
188			$label =~ s/_/ /;
189			print lc($caption) . ".label $label\n";
190			print lc($caption) . ".type DERIVE\n";
191			print lc($caption) . ".min 0\n";
192		}
193		print "graph_info Queries by DNS RR type requested\n";
194		exit 0;
195	}
196
197	my %values = map { $_ => 0 } keys %captions;
198	get_values(\%values);
199	foreach (keys %values) {
200		print lc($_) . ".value $values{$_}\n";
201	}
202
203	exit 0;
204}
205
206# Answers by rcode
207sub by_rcode($) {
208	my ($function) = shift;
209	my %captions = ();
210
211	%captions = (
212		'SAns' => 'NOERROR',
213		'SFail' => 'SERVFAIL',
214		'SFErr' => 'FORMERR',
215		'SNXD' => 'NXDOMAIN',
216	);
217
218	# Print graph configuration.
219	if ($function and $function eq "config") {
220		print "graph_title NSD DNS answers by rcode\n";
221		print "graph_args --base 1000 -l 0\n";
222		print "graph_vlabel answers / second\n";
223		print "graph_category dns\n";
224		foreach my $caption (keys %captions) {
225			my $label = $captions{$caption};
226			$label =~ s/_/ /;
227			print lc($caption) . ".label $label\n";
228			print lc($caption) . ".type DERIVE\n";
229			print lc($caption) . ".min 0\n";
230		}
231		print "graph_info Answers by rcode returned\n";
232		exit 0;
233	}
234
235	my %values = map { $_ => 0 } keys %captions;
236	get_values(\%values);
237	foreach (keys %values) {
238		# SAns is the total number of answers sent, regardless of rcode.
239		# Subtracting SERVFAIL, FORMERR and NXDOMAIN leaves IMPL and
240		# REFUSED.  NSD will never send REFUSED, which leaves IMPL - so,
241		# probably correct enough!
242		if ($_ eq "SAns") {
243			$values{$_} -= $values{'SFErr'};
244			$values{$_} -= $values{'SFail'};
245			$values{$_} -= $values{'SNXD'};
246		}
247		print lc($_) . ".value $values{$_}\n";
248	}
249
250	exit 0;
251}
252
253# Make sure we can access the pidfile and the logfile
254# and that we can send a signal to NSD to print stats.
255# Note that autoconf should exit 0 even if it fails.
256sub autoconf {
257	open(my $L, "< $logfile") || print "no ($logfile: $!)\n";
258	open(my $P, "< $pidfile") || print "no ($pidfile: $!)\n";
259	exit 0 unless defined($L) and defined($P);
260
261	eval { signal_nsd() };
262	if ($@) {
263		chomp $@;
264		warn "no ($@)\n";
265		exit 0;
266	}
267
268	print "yes\n";
269	exit 0;
270}
271
272if ($ARGV[0] and $ARGV[0] eq "autoconf") {
273	autoconf();
274}
275
276if ($Munin::Plugin::me =~ /_by_type$/) {
277	by_type($ARGV[0], $ENV{'stats'});
278} elsif ($Munin::Plugin::me =~ /_by_rcode$/) {
279	by_rcode($ARGV[0]);
280} elsif ($Munin::Plugin::me =~ /_hits$/) {
281	hits($ARGV[0]);
282}
283
284exit 0;
285