celluloid/celluloid-dns

# Copyright, 2009, 2012, by Samuel G. D. Williams. <http://www.codeotaku.com>
# 
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
# 
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

require 'resolv'

class Resolv
    class DNS
        class Message
            # Merge the given message with this message. A number of heuristics are applied in order to ensure that the result makes sense. For example, If the current message is not recursive but is being merged with a message that was recursive, this bit is maintained. If either message is authoritive, then the result is also authoritive.
            #
            # Modifies the current message in place.
            def merge! (other)
                # Authoritive Answer
                @aa = @aa && other.aa

                @question += other.question
                @answer += other.answer
                @authority += other.authority
                @additional += other.additional

                # Recursion Available
                @ra = @ra || other.ra

                # Result Code (Error Code)
                @rcode = other.rcode unless other.rcode == 0

                # Recursion Desired
                @rd = @rd || other.rd
            end
        end
        
        class OriginError < ArgumentError
        end
        
        class Name
            def to_s
                "#{@labels.join('.')}#{@absolute ? '.' : ''}"
            end
            
            def inspect
                "#<#{self.class}: #{self.to_s}>"
            end
            
            # Return the name, typically absolute, with the specified origin as a suffix. If the origin is nil, don't change the name, but change it to absolute (as specified).
            def with_origin(origin, absolute = true)
                return self.class.new(@labels, absolute) if origin == nil
                
                origin = Label.split(origin) if String === origin
                
                return self.class.new(@labels + origin, absolute)
            end
            
            
            # Return the name, typically relative, without the specified origin suffix. If the origin is nil, don't change the name, but change it to absolute (as specified).
            def without_origin(origin, absolute = false)
                return self.class.new(@labels, absolute) if origin == nil
                
                origin = Label.split(origin) if String === origin
                
                if @labels.last(origin.length) == origin
                    return self.class.new(@labels.first(@labels.length - origin.length), absolute)
                else
                    raise OriginError.new("#{self} does not end with #{origin.join('.')}")
                end
            end
        end
    end
    
    if RUBY_VERSION == "2.3.0"
        # Clearly, the Ruby 2.3.0 release was throughly tested.
        class IPv6
            def self.create(arg)
                case arg
                when IPv6
                    return arg
                when String
                    address = ''.b
                    if Regex_8Hex =~ arg
                        arg.scan(/[0-9A-Fa-f]+/) {|hex| address << [hex.hex].pack('n')}
                    elsif Regex_CompressedHex =~ arg
                        prefix = $1
                        suffix = $2
                        a1 = ''.b
                        a2 = ''.b
                        prefix.scan(/[0-9A-Fa-f]+/) {|hex| a1 << [hex.hex].pack('n')}
                        suffix.scan(/[0-9A-Fa-f]+/) {|hex| a2 << [hex.hex].pack('n')}
                        omitlen = 16 - a1.length - a2.length
                        address << a1 << "\0" * omitlen << a2
                    elsif Regex_6Hex4Dec =~ arg
                        prefix, a, b, c, d = $1, $2.to_i, $3.to_i, $4.to_i, $5.to_i
                        if (0..255) === a && (0..255) === b && (0..255) === c && (0..255) === d
                            prefix.scan(/[0-9A-Fa-f]+/) {|hex| address << [hex.hex].pack('n')}
                            address << [a, b, c, d].pack('CCCC')
                        else
                            raise ArgumentError.new("not numeric IPv6 address: " + arg)
                        end
                    elsif Regex_CompressedHex4Dec =~ arg
                        prefix, suffix, a, b, c, d = $1, $2, $3.to_i, $4.to_i, $5.to_i, $6.to_i
                        if (0..255) === a && (0..255) === b && (0..255) === c && (0..255) === d
                            a1 = ''.b
                            a2 = ''.b
                            prefix.scan(/[0-9A-Fa-f]+/) {|hex| a1 << [hex.hex].pack('n')}
                            suffix.scan(/[0-9A-Fa-f]+/) {|hex| a2 << [hex.hex].pack('n')}
                            omitlen = 12 - a1.length - a2.length
                            address << a1 << "\0" * omitlen << a2 << [a, b, c, d].pack('CCCC')
                        else
                            raise ArgumentError.new("not numeric IPv6 address: " + arg)
                        end
                    else
                        raise ArgumentError.new("not numeric IPv6 address: " + arg)
                    end
                    return IPv6.new(address)
                else
                    raise ArgumentError.new("cannot interpret as IPv6 address: #{arg.inspect}")
                end
            end
        end
    end
end