Class: Zonefile

Inherits:
Object
  • Object
show all
Defined in:
lib/zonefile/zonefile.rb

Overview

Ruby Zonefile - Parse and manipulate DNS Zone Files.

Description

This class can read, manipulate and create DNS zone files. It supports A, AAAA, MX, NS, SOA, TXT, CNAME and SRV records. The data can be accessed by the instance method of the same name. All except SOA return an array of hashes containing the named data. SOA directly returns the hash since there can only be one SOA information.

The following hash keys are returned per record type:

  • SOA

    - :ttl, :primary, :email, :serial, :refresh, :retry, :expire, :minimumTTL

  • A

    - :name, :ttl, :class, :host

  • MX

    - :name, :ttl, :class, :pri, :host

  • NS

    - :name, :ttl, :class, :host

  • CNAME

    - :name, :ttl, :class, :host

  • TXT

    - :name, :ttl, :class, :text

  • A4 (AAAA)

    - :name, :ttl, :class, :host

  • SRV

    - :name, :ttl, :class, :pri, :weight, :port, :host

Examples

Read a Zonefile

zf = Zonefile.from_file('/path/to/zonefile.db')

# Display MX-Records
zf.mx.each do |mx_record|
   puts "Mail Exchagne with priority: #{mx_record[:pri]} --> #{mx_record[:host]}"
end

# Show SOA TTL
puts "Record Time To Live: #{zf.soa[:ttl]}"

# Show A-Records
zf.a.each do |a_record|
   puts "#{a_record[:name]} --> #{a_record[:host]}"
end

Manipulate a Zonefile

zf = Zonefile.from_file('/path/to/zonefile.db')

# Change TTL and add an A-Record

zf.soa[:ttl] = '123123'	# Change the SOA ttl
zf.a << { :class => 'IN', :name => 'www', :host => '192.168.100.1', :ttl => 3600 }  # add A-Record

# Increase Serial Number
zf.new_serial

# Print new zonefile
puts "New Zonefile: \n#{zf.output}"

Author

Martin Boese, based on Simon Flack Perl library DNS::ZoneParse

Constant Summary collapse

RECORDS = 
%w{ mx a a4 ns cname txt ptr srv soa }

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(zonefile = '', file_name = nil, origin = nil) ⇒ Zonefile

create a new zonefile object by passing the content of the zonefile



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# File 'lib/zonefile/zonefile.rb', line 97

def initialize(zonefile = '', file_name= nil, origin= nil)
  @data = zonefile
  @filename = file_name
  @origin = origin
 
  @records = {}
  @soa = {}
  RECORDS.each { |r| @records[r.intern] = [] }
  parse
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(m) ⇒ Object 



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# File 'lib/zonefile/zonefile.rb', line 76

def method_missing(m)
  return super unless RECORDS.include?(m.to_s)
  @records[m]
end

Instance Attribute Details

#data ⇒ Object (readonly)

Returns the value of attribute data.



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# File 'lib/zonefile/zonefile.rb', line 74

def data
  @data
end

#records ⇒ Object (readonly)

Returns the value of attribute records.



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# File 'lib/zonefile/zonefile.rb', line 72

def records
  @records
end

#soa ⇒ Object (readonly)

Returns the value of attribute soa.



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# File 'lib/zonefile/zonefile.rb', line 73

def soa
  @soa
end

Class Method Details

.from_file(file_name, origin = nil) ⇒ Object

Create a new object by reading the content of a file



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# File 'lib/zonefile/zonefile.rb', line 109

def self.from_file(file_name, origin = nil)
   Zonefile.new(File.read(file_name), file_name.split('/').last, origin)
end

.simplify(zf) ⇒ Object

Compact a zonefile content - removes empty lines, comments, converts tabs into spaces etc…



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# File 'lib/zonefile/zonefile.rb', line 84

def self.simplify(zf)
   # concatenate everything split over multiple lines in parentheses - remove ;-comments in block
   zf = zf.gsub(/(\([^\)]*?\))/) { |m| m.split(/\n/).map { |l| l.gsub(/\;.*$/, '') }.join("\n").gsub(/[\r\n]/, '') }

   zf.split(/\n/).map do |line|
       r = line.gsub(/\t/, ' ')
       r = r.gsub(/\s+/, ' ')
       r = r.gsub(/\;.*$/, '')
   end.delete_if { |line| line.empty? || line[0].chr == ';'}.join("\n")
end

Instance Method Details

#add_record(type, data = {}) ⇒ Object 



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# File 'lib/zonefile/zonefile.rb', line 113

def add_record(type, data= {})
   @records[type.downcase.intern] << data
end

#new_serial ⇒ Object

Generates a new serial number in the format of YYYYMMDDII if possible



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# File 'lib/zonefile/zonefile.rb', line 118

def new_serial
  base = "%04d%02d%02d" % [Time.now.year, Time.now.month, Time.now.day ]

  if ((self.soa[:serial].to_i / 100) > base.to_i) then
      ns = self.soa[:serial].to_i + 1
      self.soa[:serial] = ns.to_s
      return ns.to_s
  end
  
  ii = 0
  while (("#{base}%02d" % ii).to_i <= self.soa[:serial].to_i) do
   ii += 1
  end
  self.soa[:serial] = "#{base}%02d" % ii   
end

#output ⇒ Object

Build a new nicely formatted Zonefile



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# File 'lib/zonefile/zonefile.rb', line 219

def output
   out =<<-ENDH
;
;  Database file #{@filename || 'unknown'} for #{@origin || 'unknown'} zone.
;	Zone version: #{self.soa[:serial]}
;
#{self.soa[:ttl] ? "$TTL #{self.soa[:ttl]}" : ''}
#{self.soa[:origin]}		#{self.soa[:ttl]} IN  SOA  #{self.soa[:primary]} #{self.soa[:email]} (
			#{self.soa[:serial]}	; serial number
			#{self.soa[:refresh]}	; refresh
			#{self.soa[:retry]}	; retry
			#{self.soa[:expire]}	; expire
			#{self.soa[:minimumTTL]}	; minimum TTL
			)
; Zone NS Records
ENDH
  self.ns.each do |ns|
    out <<  "#{ns[:name]}	#{ns[:ttl]}	#{ns[:class]}	NS	#{ns[:host]}\n"
  end
  out << "\n; Zone MX Records\n" unless self.mx.empty?
  self.mx.each do |mx|
    out << "#{mx[:name]}	#{mx[:ttl]}	#{mx[:class]}	MX	#{mx[:pri]} #{mx[:host]}\n"
  end
  
  self.a.each do |a|
       out <<  "#{a[:name]}	#{a[:ttl]}	#{a[:class]}	A	#{a[:host]}\n"
  end   
  self.cname.each do |cn|
    out << "#{cn[:name]}	#{cn[:ttl]}	#{cn[:class]}	CNAME	#{cn[:host]}\n"
  end  
  self.a4.each do |a4|
    out << "#{a4[:name]}	#{a4[:ttl]}	#{a4[:class]}	AAAA	#{a4[:host]}\n"
  end
  self.txt.each do |tx|
    out << "#{tx[:name]}	#{tx[:ttl]}	#{tx[:class]}	TXT	\"#{tx[:text]}\"\n"
  end
  self.srv.each do |srv|
    out << "#{srv[:name]}	#{srv[:ttl]}	#{srv[:class]}	SRV	#{srv[:pri]} #{srv[:weight]} #{srv[:port]}	#{srv[:host]}\n"
  end
  
  out
end

#parse ⇒ Object 



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# File 'lib/zonefile/zonefile.rb', line 210

def parse
   Zonefile.simplify(@data).each_line do |line|
       parse_line(line)      
   end
end

#parse_line(line) ⇒ Object 



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# File 'lib/zonefile/zonefile.rb', line 134

def parse_line(line)
   valid_name = /[\@a-z_\-\.0-9\*]+/i
   valid_ip6  = /[\@a-z_\-\.0-9\*:]+/i
   rr_class   = /\b(?:IN|HS|CH)\b/i
   rr_type    = /\b(?:NS|A|CNAME)\b/i
   rr_ttl     = /(?:\d+[wdhms]?)+/i
   ttl_cls    = Regexp.new("(?:(#{rr_ttl})\s)?(?:(#{rr_class})\s)?")

   data = {}
   if line =~ /^(#{valid_name})? \s*
                #{ttl_cls}
                (#{rr_type}) \s
                (#{valid_name})
              /ix then
             (name, ttl, dclass, type, host) = [$1, $2, $3, $4, $5]
            add_record($4, :name => $1, :ttl => $2, :class => $3, :host => $5)
   elsif line=~/^(#{valid_name})? \s*
               #{ttl_cls}
               AAAA \s
               (#{valid_ip6})               
               /x then
             add_record('a4', :name => $1, :ttl => $2, :class => $3, :host => $4)
   elsif line=~/^(#{valid_name})? \s*
                #{ttl_cls}
                MX \s
                (\d+) \s
                (#{valid_name})
              /ix then
              add_record('mx', :name => $1, :ttl => $2, :class => $3, :pri => $4.to_i, :host => $5)
   elsif line=~/^(#{valid_name})? \s*
                #{ttl_cls}
                SRV \s
                (\d+) \s
                (\d+) \s
                (\d+) \s
                (#{valid_name})
              /ix
       add_record('srv', :name => $1, :ttl => $2, :class => $3, :pri => $4, :weight => $5,
                         :port => $6, :host => $7)
   elsif line=~/^(#{valid_name}) \s+
                #{ttl_cls}
                SOA \s+
                (#{valid_name}) \s+
                (#{valid_name}) \s*
                \(?\s*
                    (#{rr_ttl}) \s+
                    (#{rr_ttl}) \s+
                    (#{rr_ttl}) \s+
                    (#{rr_ttl}) \s+
                    (#{rr_ttl}) \s*
                \)?
              /ix
           ttl = @soa[:ttl] || $2 || ''
           @soa[:origin] = $1
           @soa[:ttl] = ttl
           @soa[:primary] = $4
           @soa[:email] = $5
           @soa[:serial] = $6
           @soa[:refresh] = $7
           @soa[:retry] = $8
           @soa[:expire] = $9
           @soa[:minimumTTL] = $10

   elsif line=~ /^(#{valid_name})? \s*
               #{ttl_cls}
               PTR \s+
               (#{valid_name})
              /ix
           add_record('ptr', :name => $1, :class => $3, :ttl => $2, :host => $4)
   elsif line =~ /(#{valid_name})? \s #{ttl_cls} TXT \s \"([^\"]*)\"/ix
           add_record('txt', :name => $1, :ttl => $2, :class => $3, :text => $4)
   elsif line =~ /\$TTL\s+(#{rr_ttl})/i 
           @soa[:ttl] = $1
   end
end