collectd: add dhcp_pool.pl script

2022-04-08 16:48:02 +02:00 · 2022-04-08 16:48:02 +02:00 · e0c27ff083
parent 07f4dadd0e
commit e0c27ff083
5 changed files with 201 additions and 2 deletions
--- a/1
+++ b/1
@ -13,6 +13,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - base: import dump-server-state.sh script
 - post-install: add a version number to motd-carp-state.sh
 - nagios-nrpe : add a check dhcp_pool
+- collectd: add dhcp_pool.pl script

 ### Changed

--- a/roles/collectd/defaults/main.yml
+++ b/roles/collectd/defaults/main.yml
@ -14,6 +14,7 @@ collectd_plugin_exec_interval: "{{ collectd_interval }}"
 collectd_plugin_exec_ifq_drops: false
 collectd_plugin_exec_dns_stats: false  # Based on unbound
 collectd_plugin_exec_dns_stats_interval: "{{ collectd_interval }}"
+collectd_plugin_exec_dhcp_pool: false

 # others plugins

--- a/roles/collectd/files/dhcp_pool.pl
+++ b/roles/collectd/files/dhcp_pool.pl
@ -0,0 +1,176 @@
+#!/usr/bin/perl -w
+#
+# Copyright (C) 2008 Rien Broekstra <rien@rename-it.nl>
+#
+# 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.
+#
+#
+# Configuration variables:
+#
+#       conffile     - path to dhcpd's configuration file (default "/etc/dhcpd.conf")
+#       leasefile    - path to dhcpd's leases file (default "/var/lib/dhcp/dhcpd.leases")
+#
+
+use POSIX;
+use Time::Local;
+use Sys::Hostname;
+use strict;
+
+my $CONFFILE = exists $ENV{'conffile'} ? $ENV{'conffile'} : "/etc/dhcpd.conf";
+my $LEASEFILE = exists $ENV{'leasefile'} ? $ENV{'leasefile'} : "/var/db/dhcpd.leases";
+
+my (@activeleases, %dhcp_pools, $pool_start, $pool_end, $pool_size, $pool_free, $pool_usage, $pool_status, $label, $lease, @output);
+my $hostname = hostname;
+
+# Determine all leased IP addresses
+@activeleases = determine_active_leases();
+
+# Determine the available IP pools
+%dhcp_pools = determine_pools();
+
+# For each pool, count how many leases from that pool are currently active
+foreach $pool_start (keys %dhcp_pools) {
+    $pool_size = $dhcp_pools{$pool_start};
+    $pool_end = $pool_start+$pool_size-1;
+    $pool_free = $pool_size;
+
+    foreach $lease (@activeleases) {
+        if ($lease >= $pool_start && $lease <= $pool_end) {
+    		$pool_free--;
+        }
+    }
+
+    $label = ip2string($pool_start)."_".ip2string($pool_end);
+    $pool_usage = sprintf("%.1f", 100*($pool_size-$pool_free)/$pool_size);
+
+    push(@output, "PUTVAL $hostname/dhcp_pool/gauge-$label N:$pool_usage\n");
+}
+
+print @output;
+exit 0;
+
+################
+###### FUNCTIONS 
+
+# Parse dhcpd.conf for range statements.
+#
+# Returns a hash with start IP -> size
+sub determine_pools {
+    my (%pools, @conffile, $line, $start, $end, $size);
+
+    open(CONFFILE, "<${CONFFILE}") || exit -1;
+    @conffile = <CONFFILE>;
+    close (CONFFILE);
+
+    foreach $line (@conffile) {
+	next if $line =~ /^\s*#/;
+
+	if ($line =~ /range[\s]+([\d]+\.[\d]+\.[\d]+\.[\d]+)[\s]+([\d]+\.[\d]+\.[\d]+\.[\d]+)/) {
+	    $start = string2ip($1);
+	    $end = string2ip($2);
+
+	    defined($start) || next;
+	    defined($end) || next;
+
+            # The range statement gives the lowest and highest IP addresses in a range.
+	    $size = $end - $start + 1;
+
+	    $pools{$start} = $size;
+	}
+    }
+    return %pools;
+}
+
+# Very simple parser for dhcpd.leases. This will break very easily if dhcpd decides to
+# format the file differently. Ideally a simple recursive-descent parser should be used.
+#
+# Returns an array with currently leased IP's
+sub determine_active_leases {
+    my (@leasefile, $startdate, $enddate, $lease, @activeleases, $mytz, $line, %saw);
+
+    open(LEASEFILE, "<${LEASEFILE}") || exit -1;
+    @leasefile = <LEASEFILE>;
+    close (LEASEFILE);
+
+    @activeleases = ();
+
+    # Portable way of converting a GMT date/time string to timestamp is setting TZ to UTC, and then calling mktime()
+    $mytz = $ENV{'TZ'};
+    $ENV{'TZ'} = 'UTC 0';
+    tzset();
+
+    foreach $line (@leasefile) {
+	if ($line =~ /lease ([\d]+\.[\d]+\.[\d]+\.[\d]+)/) {
+	    $lease = string2ip($1);
+	    defined($lease) || next;
+
+	    undef $startdate;
+	    undef $enddate;
+	}
+	elsif ($line =~ /starts \d ([\d]{4})\/([\d]{2})\/([\d]{2}) ([\d]{2}):([\d]{2}):([\d]{2})/) {
+	    $startdate = mktime($6, $5, $4, $3, $2-1, $1-1900, 0, 0);
+	}
+	elsif ($line =~ /ends \d ([\d]{4})\/([\d]{2})\/([\d]{2}) ([\d]{2}):([\d]{2}):([\d]{2})/) {
+	    $enddate = mktime($6, $5, $4, $3, $2-1, $1-1900, 0, 0);
+	}
+	elsif ($line !~ /abandoned/) {
+	    if (defined($enddate) && defined($startdate) && defined($lease)) {
+		if ($startdate < time() && $enddate > time()) {
+		    push (@activeleases, $lease);
+		}
+	    }
+	}
+
+    }
+
+    # Set TZ back to its original setting
+    if (defined($mytz)) {
+	$ENV{'TZ'} = $mytz;
+    }
+    else {
+	delete $ENV{'TZ'};
+    }
+    tzset();
+
+    # Sort the array, strip doubles, and return
+    return grep(!$saw{$_}++, @activeleases);
+}
+
+#
+# Helper routine to convert an IP address a.b.c.d into an integer
+#
+# Returns an integer representation of an IP address
+sub string2ip {
+    my $string = shift;
+    defined($string) || return undef;
+    if ($string =~ /([\d]+)\.([\d]+)\.([\d]+)\.([\d]+)/) {
+	if ($1 < 0 || $1 > 255 || $2 < 0 || $2 > 255 || $3 < 0 || $3 > 255 || $4 < 0 || $4 > 255) {
+	    return undef;
+	}
+	else {
+	    return $1 << 24 | $2 << 16 | $3 << 8 | $4;
+	}
+    }
+    return undef;
+}
+
+#
+# Returns a dotted quad notation of an
+#
+sub ip2string {
+    my $ip = shift;
+    defined ($ip) || return undef;
+    return sprintf ("%d.%d.%d.%d", ($ip >> 24) & 0xff, ($ip >> 16) & 0xff, ($ip >> 8) & 0xff, $ip & 0xff);
+}
--- a/roles/collectd/tasks/main.yml
+++ b/roles/collectd/tasks/main.yml
@ -24,7 +24,7 @@
  file:
    path: /usr/local/share/collectd/scripts
    state: directory
-  when: collectd_plugin_exec_ifq_drops or collectd_plugin_exec_dns_stats
+  when: collectd_plugin_exec_ifq_drops or collectd_plugin_exec_dns_stats or collectd_plugin_exec_dhcp_pool
  tags:
    - collectd

@ -95,3 +95,21 @@
  when: collectd_plugin_exec_dns_stats
  tags:
    - collectd
+
+- name: Copy dhcp_pool.pl
+  copy:
+    src: dhcp_pool.pl
+    dest: /usr/local/share/collectd/scripts/dhcp_pool.pl
+    mode: 0755
+    force: true
+  when: collectd_plugin_exec_dhcp_pool
+  tags:
+    - collectd
+
+- name: Remove dhcp_pool.pl
+  file:
+    path: /usr/local/share/collectd/scripts/dhcp_pool.pl
+    state: absent
+  when: not collectd_plugin_exec_dhcp_pool
+  tags:
+    - collectd
--- a/roles/collectd/templates/collectd.conf.j2
+++ b/roles/collectd/templates/collectd.conf.j2
@ -6,7 +6,7 @@ LoadPlugin syslog
  LogLevel warning
 </Plugin>

-{% if (collectd_plugin_exec_ifq_drops is sameas true) or (collectd_plugin_exec_dns_stats is sameas true) %}
+{% if (collectd_plugin_exec_ifq_drops is sameas true) or (collectd_plugin_exec_dns_stats is sameas true) or (collectd_plugin_exec_dhcp_pool is sameas true) %}
 <LoadPlugin exec>
  Interval {{ collectd_plugin_exec_interval }}
 </LoadPlugin>
@ -18,6 +18,9 @@ LoadPlugin syslog
 {% if collectd_plugin_exec_dns_stats is sameas true %}
  Exec "_collectd" "/usr/local/share/collectd/scripts/dns_stats.sh"
 {% endif %}
+{% if collectd_plugin_exec_dhcp_pool is sameas true %}
+  Exec "_collectd" "/usr/local/share/collectd/scripts/dhcp_pool.pl"
+{% endif %}
 </Plugin>

 {% endif %}