Class: DNS::ResourceRecord

Inherits:
Object
  • Object
show all
Defined in:
lib/faildns/resourcerecord.rb,
lib/faildns/resourcerecord/IN/A.rb,
lib/faildns/resourcerecord/data.rb,
lib/faildns/resourcerecord/IN/MX.rb,
lib/faildns/resourcerecord/IN/NS.rb,
lib/faildns/resourcerecord/IN/PTR.rb,
lib/faildns/resourcerecord/IN/SOA.rb,
lib/faildns/resourcerecord/IN/TXT.rb,
lib/faildns/resourcerecord/IN/AAAA.rb,
lib/faildns/resourcerecord/IN/NULL.rb,
lib/faildns/resourcerecord/IN/CNAME.rb,
lib/faildns/resourcerecord/IN/HINFO.rb

Overview

– The answer, authority, and additional sections all share the same format: a variable number of resource records, where the number of records is specified in the corresponding count field in the header. Each resource record has the following format:

                                1  1  1  1  1  1
  0  1  2  3  4  5  6  7  8  9  0  1  2  3  4  5
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|                                               |
/                                               /
/                      NAME                     /
|                                               |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|                      TYPE                     |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|                     CLASS                     |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|                      TTL                      |
|                                               |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|                   RDLENGTH                    |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
/                     RDATA                     /
/                                               /
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+

where:

NAME a domain name to which this resource record pertains.

TYPE two octets containing one of the RR type codes. This

field specifies the meaning of the data in the RDATA
field.

CLASS two octets which specify the class of the data in the

RDATA field.

TTL a 32 bit unsigned integer that specifies the time

interval (in seconds) that the resource record may be
cached before it should be discarded.  Zero values are
interpreted to mean that the RR can only be used for the
transaction in progress, and should not be cached.

RDLENGTH an unsigned 16 bit integer that specifies the length in

octets of the RDATA field.

RDATA a variable length string of octets that describes the

resource.  The format of this information varies
according to the TYPE and CLASS of the resource record.
For example, the if the TYPE is A and the CLASS is IN,
the RDATA field is a 4 octet ARPA Internet address.

++

Defined Under Namespace

Modules: IN Classes: Data

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(what = {}) ⇒ ResourceRecord

Returns a new instance of ResourceRecord.



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# File 'lib/faildns/resourcerecord.rb', line 108

def initialize (what={})
  if !what.is_a? Hash
    raise ArgumentError.new('You have to pass a Hash.')
  end

  @data = what

  if block_given?
    yield self
  end
end

Class Method Details

.length(string) ⇒ Object 



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# File 'lib/faildns/resourcerecord.rb', line 102

def self.length (string)
  string.force_encoding 'BINARY'

  (tmp = DomainName.length(string) + Type.length + Class.length + 4) + string[tmp, 2].unpack('n').first + 2
end

.parse(string, original) ⇒ Object 



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# File 'lib/faildns/resourcerecord.rb', line 78

def self.parse (string, original)
  string.force_encoding 'BINARY'

  ResourceRecord.new {|r|
    r.name  = DomainName.parse(string, original)
    r.type  = Type.parse(string)
    r.class = Class.parse(string)

    r.ttl = string.unpack('N').first; string[0, 4] = ''

    r.length = string.unpack('n').first; string[0, 2] = ''
    r.data   = ResourceRecord.const_get(r.class.to_sym).const_get(r.type.to_sym) rescue nil

    if !r.data
      r.data = ResourceRecord.const_get(r.class.to_sym).const_get(:NULL)
      DNS.debug "ResourceRecord::#{r.class}::#{r.type} not found."
    end

    DNS.debug r.data.inspect, { :level => 2 }
    
    r.data = r.data.parse(string, r.length, original)
  }
end

Instance Method Details

#class ⇒ Object 



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# File 'lib/faildns/resourcerecord.rb', line 122

def class;  @data[:CLASS]    end

#class=(val) ⇒ Object 



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# File 'lib/faildns/resourcerecord.rb', line 129

def class= (val);  @data[:CLASS]    = Class.new(val)      end

#data ⇒ Object 



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# File 'lib/faildns/resourcerecord.rb', line 125

def data;   @data[:RDATA]    end

#data=(val) ⇒ Object 



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# File 'lib/faildns/resourcerecord.rb', line 132

def data= (val);   @data[:RDATA]    = val                 end

#length ⇒ Object 



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# File 'lib/faildns/resourcerecord.rb', line 124

def length; @data[:RDLENGTH] end

#length=(val) ⇒ Object 



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# File 'lib/faildns/resourcerecord.rb', line 131

def length= (val); @data[:RDLENGTH] = val                 end

#name ⇒ Object 



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# File 'lib/faildns/resourcerecord.rb', line 120

def name;   @data[:NAME]     end

#name=(val) ⇒ Object 



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# File 'lib/faildns/resourcerecord.rb', line 127

def name= (val);   @data[:NAME]     = DomainName.new(val) end

#pack ⇒ Object 



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# File 'lib/faildns/resourcerecord.rb', line 134

def pack
  self.name.pack + self.type.pack + self.class.pack + [self.ttl].pack('N') +
  [self.length].pack('n') + self.data.pack
end

#ttl ⇒ Object 



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# File 'lib/faildns/resourcerecord.rb', line 123

def ttl;    @data[:TTL]      end

#ttl=(val) ⇒ Object 



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# File 'lib/faildns/resourcerecord.rb', line 130

def ttl= (val);    @data[:TTL]      = val                 end

#type ⇒ Object 



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# File 'lib/faildns/resourcerecord.rb', line 121

def type;   @data[:TYPE]     end

#type=(val) ⇒ Object 



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# File 'lib/faildns/resourcerecord.rb', line 128

def type= (val);   @data[:TYPE]     = Type.new(val)       end