dsa-nagios-checks/checks/dsa-check-soas

   1 #!/usr/bin/ruby
   2
   3 # Copyright 2006, 2012, 2014 Peter Palfrader
   4 #           2012  Uli Martens
   5 #
   6 # Permission is hereby granted, free of charge, to any person obtaining
   7 # a copy of this software and associated documentation files (the
   8 # "Software"), to deal in the Software without restriction, including
   9 # without limitation the rights to use, copy, modify, merge, publish,
  10 # distribute, sublicense, and/or sell copies of the Software, and to
  11 # permit persons to whom the Software is furnished to do so, subject to
  12 # the following conditions:
  13 #
  14 # The above copyright notice and this permission notice shall be
  15 # included in all copies or substantial portions of the Software.
  16 #
  17 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  18 # EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  19 # MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  20 # NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  21 # LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  22 # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  23 # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  24
  25
  26 # the each_resource function is lifted from ruby 1.9.1's resolv.rb, with the
  27 # minor modification that we do not unconditionally set the message's RD flag
  28 # to 1.  Its license is:
  29 #
  30 # Copyright (C) 1993-2010 Yukihiro Matsumoto. All rights reserved.
  31 #
  32 # Redistribution and use in source and binary forms, with or without
  33 # modification, are permitted provided that the following conditions
  34 # are met:
  35 # 1. Redistributions of source code must retain the above copyright
  36 # notice, this list of conditions and the following disclaimer.
  37 # 2. Redistributions in binary form must reproduce the above copyright
  38 # notice, this list of conditions and the following disclaimer in the
  39 # documentation and/or other materials provided with the distribution.
  40 #
  41 # THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  42 # ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  43 # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  44 # ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  45 # FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  46 # DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  47 # OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  48 # HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  49 # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  50 # OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  51 # SUCH DAMAGE.
  52
  53
  54 require 'ipaddr'
  55 require 'resolv'
  56 require 'optparse'
  57 require 'yaml'
  58
  59 NAGIOS_STATUS = { :OK => 0, :WARNING => 1, :CRITICAL => 2, :UNKNOWN => -1 };
  60 @verbose = 0;
  61 @additional_nameservers = []
  62 @check_soa_nameservers = true;
  63
  64 def show_help(parser, code=0, io=STDOUT)
  65   program_name = File.basename($0, '.*')
  66   io.puts "Usage: #{program_name} [options] <domainname> [<domainname> ...]"
  67   io.puts parser.summarize
  68   exit(code)
  69 end
  70 ARGV.options do |opts|
  71         opts.on_tail("-h", "--help" , "Display this help screen")                               { show_help(opts) }
  72         opts.on("-v", "--verbose"   , String, "Be verbose")                                     { @verbose += 1 }
  73         opts.on("-a", "--add=HOST"  , String, "Also check SOA on <nameserver>")                 { |val| @additional_nameservers << val }
  74         opts.on("-n", "--no-soa-ns" , String, "Don't query SOA record for list of nameservers") { @check_soa_nameservers = false }
  75         opts.parse!
  76 end
  77 show_help(ARGV.options, 1, STDERR) if ARGV.length == 0
  78
  79 if @additional_nameservers.count <= 1 and not @check_soa_nameservers
  80         program_name = File.basename($0, '.*')
  81         STDERR.puts "#{program_name}: Only know about #{@additional_nameservers.count} nameserver(s) and --no-soa-ns specified.  I want at least two."
  82         exit(1)
  83 end
  84
  85 class DSADNS < Resolv::DNS
  86         attr_reader :rd
  87         attr_writer :rd
  88
  89         def initialize(*args)
  90                 super
  91                 @rd = 1
  92         end
  93
  94         def each_resource(name, typeclass, &proc)
  95                 lazy_initialize
  96                 requester = make_udp_requester
  97                 senders = {}
  98                 begin
  99                         @config.resolv(name) {|candidate, tout, nameserver, port|
 100                                 msg = Message.new
 101 puts @rd
 102                                 msg.rd = @rd
 103                                 msg.add_question(candidate, typeclass)
 104                                 unless sender = senders[[candidate, nameserver, port]]
 105                                         sender = senders[[candidate, nameserver, port]] =
 106                                                 requester.sender(msg, candidate, nameserver, port)
 107                                 end
 108                                 reply, reply_name = requester.request(sender, tout)
 109                                 case reply.rcode
 110                                 when RCode::NoError
 111                                         if reply.tc == 1 and not Requester::TCP === requester
 112                                                 requester.close
 113                                                 # Retry via TCP:
 114                                                 requester = make_tcp_requester(nameserver, port)
 115                                                 senders = {}
 116                                                 # This will use TCP for all remaining candidates (assuming the
 117                                                 # current candidate does not already respond successfully via
 118                                                 # TCP). This makes sense because we already know the full
 119                                                 # response will not fit in an untruncated UDP packet.
 120                                                 redo
 121                                         else
 122                                                 extract_resources(reply, reply_name, typeclass, &proc)
 123                                         end
 124                                         return
 125                                 when RCode::NXDomain
 126                                         raise Config::NXDomain.new(reply_name.to_s)
 127                                 else
 128                                         raise Config::OtherResolvError.new(reply_name.to_s)
 129                                 end
 130                         }
 131                 ensure
 132                         requester.close
 133                 end
 134         end
 135 end
 136
 137 warnings = []
 138 oks = []
 139
 140 def resolve_ns(dns, domain, nameserver)
 141         puts "Getting A record for nameserver #{nameserver} for #{domain}" if @verbose > 0
 142         arecords = dns.getresources(nameserver, Resolv::DNS::Resource::IN::A)
 143         warnings << "Nameserver #{nameserver} for #{domain} has #{arecords.length} A records" if arecords.length != 1
 144         addresses = arecords.map { |a| a.address.to_s }
 145         puts "Addresses for nameserver #{nameserver} for #{domain}: #{addresses.join(', ')}" if @verbose > 0
 146         return addresses
 147 end
 148
 149 dns = Resolv::DNS.new
 150 ARGV.each{ |domain|
 151         serial = []
 152         nameserver_addresses = {}
 153         if @check_soa_nameservers
 154                 nameservers = dns.getresources(domain, Resolv::DNS::Resource::IN::NS)
 155                 nameservernames = nameservers.collect{ |ns| ns.name.to_s }
 156                 nameservernames.each do |nameserver|
 157                         addrs = resolve_ns(dns, domain, nameserver)
 158                         warnings << "Duplicate nameserver #{nameserver} for #{domain}" if nameserver_addresses[nameserver]
 159                         nameserver_addresses[nameserver] = addrs
 160                 end
 161         end
 162         @additional_nameservers.each do |ns|
 163                 begin
 164                         ipa = IPAddr.new(ns)  # check if it's an address
 165                         addrs = [ns]
 166                 rescue ArgumentError
 167                         addrs = resolve_ns(dns, domain, ns)
 168                 end
 169                 warnings << "Duplicate nameserver #{ns} for #{domain}" if nameserver_addresses[ns]
 170                 nameserver_addresses[ns] = addrs
 171         end
 172
 173         nameserver_addresses.each_pair do |nameserver, addrs|
 174                 puts "Testing nameserver #{nameserver} for #{domain}" if @verbose > 0
 175                 addrs.each do |a|
 176                         puts " Nameserver #{nameserver} is at #{a}" if @verbose > 0
 177                         begin
 178                                 resolver = DSADNS.new({:nameserver => a})
 179                                 resolver.rd = 0
 180                                 soas = resolver.getresources(domain, Resolv::DNS::Resource::IN::SOA)
 181                         rescue SystemCallError => e
 182                                 warnings << "Could not resolve #{domain} on #{nameserver}: #{e.message}"
 183                         else
 184                                 resolver.close
 185                                 warnings << "Nameserver #{nameserver} for #{domain} returns #{soas.length} SOAs" if soas.length != 1
 186                                 soas.each do |soa|
 187                                         puts " Nameserver #{nameserver} returns serial #{soa.serial} for #{domain}" if @verbose > 0
 188                                         serial << soa.serial unless serial.include? soa.serial
 189                                 end
 190                         end
 191                 end
 192         end
 193         case serial.length
 194                 when 0
 195                         warnings << "Found no serials for #{domain}"
 196                 when 1
 197                         oks << "#{domain} is at #{serial.first}"
 198                 else
 199                         warnings << "Nameservers disagree on serials for #{domain}: found #{serial.join(', ')}" if serial.length != 1
 200         end
 201 }
 202 dns.close
 203
 204 if warnings.length > 0
 205         puts warnings.join('; ')
 206         exit NAGIOS_STATUS[:WARNING]
 207 else
 208         puts oks.join('; ')
 209         exit NAGIOS_STATUS[:OK]
 210 end