Class: ReDNS::Name

Inherits:
Fragment show all
Defined in:
lib/redns/name.rb

Constant Summary collapse

POINTER_CHAIN_LIMIT =

Constants ============================================================

64

Instance Attribute Summary

Attributes inherited from Fragment

#attributes

Instance Method Summary collapse

Methods inherited from Fragment

attribute

Methods included from Support

#addr_to_arpa, #bind_all_addr, #default_nameservers, #default_resolver_address, #dns_port, #inet_aton, #inet_ntoa, #io_nonblock, #io_nonblock?, #io_set_nonblock, #is_ip?

Constructor Details

#initialize(contents = nil) ⇒ Name

Instance Methods =====================================================



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# File 'lib/redns/name.rb', line 12

def initialize(contents = nil)
  case (contents)
  when ReDNS::Buffer
    # Ensure that this String subclass is handled using the default
    # method, not intercepted and treated as an actual String
    super(contents)
  when String
    super(:name => contents)
    
    unless (ReDNS::Support.is_ip?(name) or self.name.match(/\.$/))
      self.name += '.'
    end
  else
    super(contents)
  end
end

Instance Method Details

#deserialize(buffer) ⇒ Object 



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# File 'lib/redns/name.rb', line 55

def deserialize(buffer)
	self.name = ''
	
	return_to_offset = nil
	pointer_count = 0

   while (c = buffer.unpack('C')[0])
     if (c & 0xC0 == 0xC0)
       # This is part of a pointer to another section, so advance to that
       # point and read from there, but preserve the position where the
       # pointer was found to leave the buffer in that final state.

       if (additional_offset = buffer.unpack('C')[0])
         pointer = (c & 0x3F << 8) | additional_offset

         return_to_offset ||= buffer.offset
         buffer.rewind
         buffer.advance(pointer)
         
         pointer_count += 1
         
         if (pointer_count > POINTER_CHAIN_LIMIT)
           # Encountered too many pointers, probably a sign of a circular
           # reference or a badly constructed response. Ignore.
           break
         end
       else
         # The buffer may have prematurely run dry, in which case the only
         # option left is to abandon further processing.
         break
       end
     elsif (c == 0)
       break
     else
       if (read = buffer.read(c))
         name << read
         name << '.'
       else
         break
       end
     end
   end
   
   if (return_to_offset)
     buffer.rewind
     buffer.advance(return_to_offset)
   end
   
   self
end

#empty? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/redns/name.rb', line 41

def empty?
	name == '.'
end

#length ⇒ Object 



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# File 'lib/redns/name.rb', line 37

def length
	to_s.length
end

#serialize(buffer = ReDNS::Buffer.new) ⇒ Object 



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# File 'lib/redns/name.rb', line 45

def serialize(buffer = ReDNS::Buffer.new)
	buffer.append(
	  self.name.split(/\./).collect { |l| [ l.length, l ].pack("ca*") }.join('')
	)

	buffer.append("\0")
	
	buffer
end

#to_a ⇒ Object 



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# File 'lib/redns/name.rb', line 33

def to_a
	[ self.name ]
end

#to_s ⇒ Object 



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# File 'lib/redns/name.rb', line 29

def to_s
  self.name
end