Class: IPAddress::IPv6::Mapped

Inherits:
IPAddress::IPv6 show all
Defined in:
lib/ipaddress/ipv6.rb

Overview

It is usually identified as a IPv4 mapped IPv6 address, a particular IPv6 address which aids the transition from IPv4 to IPv6. The structure of the address is

::ffff:w.y.x.z

where w.x.y.z is a normal IPv4 address. For example, the following is a mapped IPv6 address:

::ffff:192.168.100.1

IPAddress is very powerful in handling mapped IPv6 addresses, as the IPv4 portion is stored internally as a normal IPv4 object. Let’s have a look at some examples. To create a new mapped address, just use the class builder itself

ip6 = IPAddress::IPv6::Mapped.new "::ffff:172.16.10.1/128"

or just use the wrapper method

ip6 = IPAddress "::ffff:172.16.10.1/128"

Let’s check it’s really a mapped address:

ip6.mapped?
  #=> true

ip6.to_string
  #=> "::FFFF:172.16.10.1/128"

Now with the ipv4 attribute, we can easily access the IPv4 portion of the mapped IPv6 address:

ip6.ipv4.address
  #=> "172.16.10.1"

Internally, the IPv4 address is stored as two 16 bits groups. Therefore all the usual methods for an IPv6 address are working perfectly fine:

ip6.to_hex
  #=> "00000000000000000000ffffac100a01"

ip6.address
  #=> "0000:0000:0000:0000:0000:ffff:ac10:0a01"

A mapped IPv6 can also be created just by specify the address in the following format:

ip6 = IPAddress "::172.16.10.1"

That is, two colons and the IPv4 address. However, as by RFC, the ffff group will be automatically added at the beginning

ip6.to_string
  => "::ffff:172.16.10.1/128"

making it a mapped IPv6 compatible address.

Constant Summary

Constants inherited from IPAddress::IPv6

IN6FORMAT

Constants included from IPAddress

AUTHORS, GEM, NAME

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods inherited from IPAddress::IPv6

#<=>, #[], #address, #bits, #broadcast_u128, compress, #compressed, #data, #each, expand, #groups, groups, #hexs, #include?, #literal, #loopback?, #network, #network?, #network_u128, parse_data, parse_hex, parse_u128, #prefix, #prefix=, #reverse, #size, #to_hex, #to_i, #to_string_uncompressed, #unspecified?

Methods included from IPAddress

deprecate, #ipv4?, #ipv6?, parse, valid?, valid_ipv4?, valid_ipv4_netmask?, valid_ipv6?

Constructor Details

#initialize(str) ⇒ Mapped

Creates a new IPv6 IPv4-mapped address

ip6 = IPAddress::IPv6::Mapped.new "::ffff:172.16.10.1/128"

ipv6.ipv4.class
  #=> IPAddress::IPv4

An IPv6 IPv4-mapped address can also be created using the IPv6 only format of the address:

ip6 = IPAddress::IPv6::Mapped.new "::0d01:4403"

ip6.to_string
  #=> "::ffff:13.1.68.3"



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# File 'lib/ipaddress/ipv6.rb', line 834

def initialize(str)
  string, netmask = str.split("/")
  if string =~ /\./ # IPv4 in dotted decimal form
    @ipv4 = IPAddress::IPv4.extract(string)
  else # IPv4 in hex form
    groups = IPAddress::IPv6.groups(string)
    @ipv4 = IPAddress::IPv4.parse_u32((groups[-2]<< 16)+groups[-1])
  end
  super("::ffff:#{@ipv4.to_ipv6}/#{netmask}")
end

Instance Attribute Details

#ipv4 ⇒ Object (readonly)

Access the internal IPv4 address



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# File 'lib/ipaddress/ipv6.rb', line 816

def ipv4
  @ipv4
end

Instance Method Details

#mapped? ⇒ Boolean

Checks if the IPv6 address is IPv4 mapped

ip6 = IPAddress "::ffff:172.16.10.1/128"

ip6.mapped?
  #=> true

Returns:

  • (Boolean) 


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# File 'lib/ipaddress/ipv6.rb', line 880

def mapped?
  true
end

#to_s ⇒ Object

Similar to IPv6#to_s, but prints out the IPv4 address in dotted decimal format

ip6 = IPAddress "::ffff:172.16.10.1/128"

ip6.to_s
  #=> "::ffff:172.16.10.1"



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# File 'lib/ipaddress/ipv6.rb', line 854

def to_s
  "::ffff:#{@ipv4.address}"
end

#to_string ⇒ Object

Similar to IPv6#to_string, but prints out the IPv4 address in dotted decimal format

ip6 = IPAddress "::ffff:172.16.10.1/128"

ip6.to_string
  #=> "::ffff:172.16.10.1/128"



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# File 'lib/ipaddress/ipv6.rb', line 868

def to_string
  "::ffff:#{@ipv4.address}/#@prefix"
end