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# -*- coding: binary -*-
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##
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#
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# Net::DNS::RR::A
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#
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# $id$
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#
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##
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require 'ipaddr'
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module Net # :nodoc:
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  module DNS 
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    class RR 
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      # =Name
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      #
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      # Net::DNS::RR::A   DNS A resource record
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      #
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      # =Synopsis
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      #
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      # require "net/dns/rr"
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      #
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      # =Description
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      #
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      # Net::DNS::RR::A is the class to handle resource records of type A, the
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      # most common in a DNS query. Its resource data is an IPv4 (i.e. 32 bit
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      # long) address, hold in the instance variable +address+.  
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      #    a = Net::DNS::RR::A.new("localhost.movie.edu. 360 IN A 127.0.0.1")
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      #
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      #    a = Net::DNS::RR::A.new(:name    => "localhost.movie.edu.",
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      #                            :ttl     => 360,
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      #                            :cls     => Net::DNS::IN,
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      #                            :type    => Net::DNS::A,
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      #                            :address => "127.0.0.1")
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      #
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      # When computing binary data to transmit the RR, the RDATA section is an
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      # Internet address expressed as four decimal numbers separated by dots
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      # without any embedded spaces (e.g.,"10.2.0.52" or "192.0.5.6").
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      #
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      class A < RR
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        attr_reader :address
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        # Assign to the RR::A object a new IPv4 address, which can be in the
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        # form of a string or an IPAddr object
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        #
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        #   a.address = "192.168.0.1"
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        #   a.address = IPAddr.new("10.0.0.1")
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        #
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        def address=(addr)
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          @address = check_address addr
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          build_pack
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        end # address=
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        private
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        def check_address(addr)
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          address = ""
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          case addr
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          when String 
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            address = IPAddr.new addr
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          when Integer # Address in numeric form
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            tempAddr = [(addr>>24),(addr>>16)&0xFF,(addr>>8)&0xFF,addr&0xFF]
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            tempAddr = tempAddr.collect {|x| x.to_s}.join(".")
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            address = IPAddr.new tempAddr
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          when IPAddr
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            address = addr
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          else
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            raise RRArgumentError, "Unknown address type: #{addr}"
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          end
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          raise RRArgumentError, "Must specify an IPv4 address" unless address.ipv4?
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          address
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        rescue ArgumentError
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          raise RRArgumentError, "Invalid address #{addr}"
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        end
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        def build_pack
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          @address_pack = @address.hton
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          @rdlength = @address_pack.size
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        end
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        def set_type
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          @type = Net::DNS::RR::Types.new("A")
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        end
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        def get_data
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          @address_pack
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        end
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        def get_inspect
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          "#@address"
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        end
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        def subclass_new_from_hash(args)
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          if args.has_key? :address 
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            @address = check_address args[:address]
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          elsif args.has_key? :rdata
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            @address = check_address args[:rdata]
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          else
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            # Address field is mandatory
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            raise RRArgumentError, ":address field is mandatory but missing"
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          end
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        end
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        def subclass_new_from_string(str)
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          @address = check_address(str)
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        end
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        def subclass_new_from_binary(data,offset)
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          a,b,c,d = data.unpack("@#{offset} CCCC")
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          @address = IPAddr.new "#{a}.#{b}.#{c}.#{d}"
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          return offset + 4
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        end
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      end # class A
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    end # class RR
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  end # module DNS
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end # module Net
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