Module: IPAddrExtensions::ClassMethods

Defined in:
lib/ipaddr_extensions.rb

Instance Method Summary collapse

Instance Method Details

#generate_ULA(mac, subnet_id = 0, locally_assigned = true) ⇒ Object

Generate an IPv6 Unique Local Address using the supplied system MAC address. Note that the MAC address is just used as a source of randomness, so where you get it from is not important and doesn’t restrict this ULA to just that system. See RFC4193



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# File 'lib/ipaddr_extensions.rb', line 495

def generate_ULA(mac, subnet_id = 0, locally_assigned=true)
  now = Time.now.utc
  ntp_time = ((now.to_i + 2208988800) << 32) + now.nsec # Convert time to an NTP timstamp.
  system_id = '::/64'.to_ip.eui_64(mac).to_i # Generate an EUI64 from the provided MAC address.
  key = [ ntp_time, system_id ].pack('QQ') # Pack the ntp timestamp and the system_id into a binary string
  global_id = Digest::SHA1.digest( key ).unpack('QQ').last & 0xffffffffff # Use only the last 40 bytes of the SHA1 digest.

  prefix =
  (126 << 121) + # 0xfc (bytes 0..6)
  ((locally_assigned ? 1 : 0) << 120) + # locally assigned? (byte 7)
  (global_id << 80) + # 40 bit global idenfitier (bytes 8..48)
  ((subnet_id & 0xffff) << 64) # 16 bit subnet_id (bytes 48..64)

  prefix.to_ip(Socket::AF_INET6).tap { |p| p.length = 64 }
end

#mask_by_default ⇒ Object

By default IPAddr masks a non all-ones prefix so that the “network address” is all that’s stored. This loses data for some applications and isn’t really necessary since anyone expecting that should use #first instead. This defaults to on to retain compatibility with the rubycore IPAddr class.



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# File 'lib/ipaddr_extensions.rb', line 480

def mask_by_default
  # You can't use ||= for bools.
  if @mask_by_default.nil?
    @mask_by_default = true
  end
  @mask_by_default
end

#mask_by_default=(x) ⇒ Object 



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# File 'lib/ipaddr_extensions.rb', line 487

def mask_by_default=(x)
  @mask_by_default = !!x
end