Class: IPAddress::IPv4

Inherits:
Object
  • Object
show all
Includes:
Comparable, Enumerable, IPAddress
Defined in:
lib/ipaddress/ipv4.rb

Overview

Name

IPAddress::IPv4 - IP version 4 address manipulation library

Synopsis

require 'ipaddress'

Description

Class IPAddress::IPv4 is used to handle IPv4 type addresses.

Constant Summary collapse

CLASSFUL =

This Hash contains the prefix values for Classful networks

Note that classes C, D and E will all have a default prefix of /24 or 255.255.255.0

{
  /^0../ => 8,  # Class A, from 0.0.0.0 to 127.255.255.255
  /^10./ => 16, # Class B, from 128.0.0.0 to 191.255.255.255
  /^110/ => 24  # Class C, D and E, from 192.0.0.0 to 255.255.255.254
}
REGEXP =

Regular expression to match an IPv4 address

Regexp.new(/((25[0-5]|2[0-4]\d|1\d\d|[1-9]\d|\d)\.){3}(25[0-5]|2[0-4]\d|1\d\d|[1-9]\d|\d)/)

Constants included from IPAddress

AUTHORS, GEM, NAME

Class Method Summary collapse

Instance Method Summary collapse

Methods included from IPAddress

demongoize, deprecate, evolve, #ipv4?, #ipv6?, mongoize, #mongoize, ntoa, parse, valid?, valid_ip?, valid_ipv4?, valid_ipv4_netmask?, valid_ipv4_subnet?, valid_ipv6?, valid_ipv6_subnet?

Constructor Details

#initialize(str) ⇒ IPv4

Creates a new IPv4 address object.

An IPv4 address can be expressed in any of the following forms:

  • “10.1.1.1/24”: ip address and prefix. This is the common and

suggested way to create an object .

  • “10.1.1.1/255.255.255.0”: ip address and netmask. Although

convenient sometimes, this format is less clear than the previous one.

  • “10.1.1.1”: if the address alone is specified, the prefix will be

set as default 32, also known as the host prefix

Examples:

# These two are the same
ip = IPAddress::IPv4.new("10.0.0.1/24")
ip = IPAddress("10.0.0.1/24")

# These two are the same
IPAddress::IPv4.new "10.0.0.1/8"
IPAddress::IPv4.new "10.0.0.1/255.0.0.0"

Raises:

  • (ArgumentError)

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# File 'lib/ipaddress/ipv4.rb', line 63

def initialize(str)
  raise ArgumentError, "Nil IP" unless str
  ip, netmask = str.split("/")
  
  # Check the ip and remove white space
  if IPAddress.valid_ipv4?(ip)
    @address = ip.strip
  else
    raise ArgumentError, "Invalid IP #{ip.inspect}"
  end
  
  # Check the netmask
  if netmask  # netmask is defined
    netmask.strip!
    if netmask =~ /^\d{1,2}$/  # netmask in cidr format 
      @prefix = Prefix32.new(netmask.to_i)
    elsif IPAddress.valid_ipv4_netmask?(netmask)  # netmask in IP format
      @prefix = Prefix32.parse_netmask(netmask)
    else  # invalid netmask
      raise ArgumentError, "Invalid netmask #{netmask}"
    end
  else  # netmask is nil, reverting to defaul classful mask
    @prefix = Prefix32.new(32)
  end

  # Array formed with the IP octets
  @octets = @address.split(".").map{|i| i.to_i}
  # 32 bits interger containing the address
  @u32 = (@octets[0]<< 24) + (@octets[1]<< 16) + (@octets[2]<< 8) + (@octets[3])
  
  @allocator = 0
end

Class Method Details

.extract(str) ⇒ Object

Extract an IPv4 address from a string and returns a new object

Example:

str = "foobar172.16.10.1barbaz"
ip = IPAddress::IPv4::extract str

ip.to_s
  #=> "172.16.10.1"

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# File 'lib/ipaddress/ipv4.rb', line 962

def self.extract(str)
  self.new REGEXP.match(str).to_s
end

.parse_classful(ip) ⇒ Object

Creates a new IPv4 address object by parsing the address in a classful way.

Classful addresses have a fixed netmask based on the class they belong to:

  • Class A, from 0.0.0.0 to 127.255.255.255

  • Class B, from 128.0.0.0 to 191.255.255.255

  • Class C, D and E, from 192.0.0.0 to 255.255.255.254

Example:

ip = IPAddress::IPv4.parse_classful "10.0.0.1"

ip.netmask 
  #=> "255.0.0.0"
ip.a?
  #=> true

Note that classes C, D and E will all have a default prefix of /24 or 255.255.255.0


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# File 'lib/ipaddress/ipv4.rb', line 1073

def self.parse_classful(ip)
  if IPAddress.valid_ipv4?(ip)
    address = ip.strip
  else
    raise ArgumentError, "Invalid IP #{ip.inspect}"
  end
  prefix = CLASSFUL.find{|h,k| h === ("%.8b" % address.to_i)}.last
  self.new "#{address}/#{prefix}"
end

.parse_data(str, prefix = 32) ⇒ Object

Creates a new IPv4 object from binary data, like the one you get from a network stream.

For example, on a network stream the IP 172.16.0.1 is represented with the binary “254020n001”.

ip = IPAddress::IPv4::parse_data "\254\020\n\001"
ip.prefix = 24

ip.to_string
  #=> "172.16.10.1/24"

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# File 'lib/ipaddress/ipv4.rb', line 946

def self.parse_data(str, prefix=32)
  self.new(str.unpack("C4").join(".")+"/#{prefix}")
end

.parse_u32(u32, prefix = 32) ⇒ Object

Creates a new IPv4 object from an unsigned 32bits integer.

ip = IPAddress::IPv4::parse_u32(167772160)

ip.prefix = 8
ip.to_string
  #=> "10.0.0.0/8"

The prefix parameter is optional:

ip = IPAddress::IPv4::parse_u32(167772160, 8)

ip.to_string
  #=> "10.0.0.0/8"

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# File 'lib/ipaddress/ipv4.rb', line 929

def self.parse_u32(u32, prefix=32)
  self.new([u32].pack("N").unpack("C4").join(".")+"/#{prefix}")
end

.summarize(*args) ⇒ Object

Summarization (or aggregation) is the process when two or more networks are taken together to check if a supernet, including all and only these networks, exists. If it exists then this supernet is called the summarized (or aggregated) network.

It is very important to understand that summarization can only occur if there are no holes in the aggregated network, or, in other words, if the given networks fill completely the address space of the supernet. So the two rules are:

1) The aggregate network must contain all the IP addresses of the

original networks;

2) The aggregate network must contain only the IP addresses of the

original networks;

A few examples will help clarify the above. Let's consider for instance the following two networks:

ip1 = IPAddress("172.16.10.0/24")
ip2 = IPAddress("172.16.11.0/24")

These two networks can be expressed using only one IP address network if we change the prefix. Let Ruby do the work:

IPAddress::IPv4::summarize(ip1,ip2).to_s
  #=> "172.16.10.0/23"

We note how the network “172.16.10.0/23” includes all the addresses specified in the above networks, and (more important) includes ONLY those addresses.

If we summarized ip1 and ip2 with the following network:

"172.16.0.0/16"

we would have satisfied rule #1 above, but not rule #2. So “172.16.0.0/16” is not an aggregate network for ip1 and ip2.

If it's not possible to compute a single aggregated network for all the original networks, the method returns an array with all the aggregate networks found. For example, the following four networks can be aggregated in a single /22:

ip1 = IPAddress("10.0.0.1/24")
ip2 = IPAddress("10.0.1.1/24")
ip3 = IPAddress("10.0.2.1/24")
ip4 = IPAddress("10.0.3.1/24")

IPAddress::IPv4::summarize(ip1,ip2,ip3,ip4).to_string
  #=> "10.0.0.0/22",

But the following networks can't be summarized in a single network:

ip1 = IPAddress("10.0.1.1/24")
ip2 = IPAddress("10.0.2.1/24")
ip3 = IPAddress("10.0.3.1/24")
ip4 = IPAddress("10.0.4.1/24")

IPAddress::IPv4::summarize(ip1,ip2,ip3,ip4).map{|i| i.to_string}
  #=> ["10.0.1.0/24","10.0.2.0/23","10.0.4.0/24"]

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# File 'lib/ipaddress/ipv4.rb', line 1028

def self.summarize(*args)
  # one network? no need to summarize
  return [args.first.network] if args.size == 1
  
  i = 0
  result = args.dup.sort.map{|ip| ip.network}
  while i < result.size-1
    sum = result[i] + result[i+1]
    result[i..i+1] = sum.first if sum.size == 1
    i += 1
  end
  
  result.flatten!
  if result.size == args.size
    # nothing more to summarize
    return result
  else
    # keep on summarizing
    return self.summarize(*result)
  end
end

Instance Method Details

#+(oth) ⇒ Object

Returns a new IPv4 object which is the result of the summarization, if possible, of the two objects

Example:

ip1 = IPAddress("172.16.10.1/24")
ip2 = IPAddress("172.16.11.2/24")

p (ip1 + ip2).map {|i| i.to_string}
  #=> ["172.16.10.0/23"]

If the networks are not contiguous, returns the two network numbers from the objects

ip1 = IPAddress("10.0.0.1/24")
ip2 = IPAddress("10.0.2.1/24")

p (ip1 + ip2).map {|i| i.to_string}
  #=> ["10.0.0.0/24","10.0.2.0/24"]

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# File 'lib/ipaddress/ipv4.rb', line 845

def +(oth)
  aggregate(*[self,oth].sort.map{|i| i.network})
end

#-(oth) ⇒ Object

Returns the difference between two IP addresses in unsigned int 32 bits format

Example:

ip1 = IPAddress("172.16.10.0/24")
ip2 = IPAddress("172.16.11.0/24")

puts ip1 - ip2
  #=> 256

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# File 'lib/ipaddress/ipv4.rb', line 819

def -(oth)
  return (to_u32 - oth.to_u32).abs
end

#<=>(oth) ⇒ Object

Spaceship operator to compare IPv4 objects

Comparing IPv4 addresses is useful to ordinate them into lists that match our intuitive perception of ordered IP addresses.

The first comparison criteria is the u32 value. For example, 10.100.100.1 will be considered to be less than 172.16.0.1, because, in a ordered list, we expect 10.100.100.1 to come before 172.16.0.1.

The second criteria, in case two IPv4 objects have identical addresses, is the prefix. An higher prefix will be considered greater than a lower prefix. This is because we expect to see 10.100.100.0/24 come before 10.100.100.0/25.

Example:

ip1 = IPAddress "10.100.100.1/8"
ip2 = IPAddress "172.16.0.1/16"
ip3 = IPAddress "10.100.100.1/16"

ip1 < ip2
  #=> true
ip1 > ip3
  #=> false

[ip1,ip2,ip3].sort.map{|i| i.to_string}
  #=> ["10.100.100.1/8","10.100.100.1/16","172.16.0.1/16"]

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# File 'lib/ipaddress/ipv4.rb', line 513

def <=>(oth)
  return nil unless oth.is_a?(self.class)
  return prefix <=> oth.prefix if to_u32 == oth.to_u32  
  to_u32 <=> oth.to_u32
end

#[](index) ⇒ Object Also known as: octet

Returns the octet specified by index

ip = IPAddress("172.16.100.50/24")

ip[0]
  #=> 172
ip[1]
  #=> 16
ip[2]
  #=> 100
ip[3]
  #=> 50

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# File 'lib/ipaddress/ipv4.rb', line 287

def [](index)
  @octets[index]
end

#[]=(index, value) ⇒ Object Also known as: octet=

Updated the octet specified at index

ip = IPAddress("172.16.100.50/24")
ip[2] = 200

#=>  #<IPAddress::IPv4:0x00000000000000 @address="172.16.200.1", 
#=>       @prefix=32, @octets=[172, 16, 200, 1], @u32=2886780929>

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# File 'lib/ipaddress/ipv4.rb', line 301

def []=(index, value)
  @octets[index] = value.to_i
  initialize("#{@octets.join('.')}/#{prefix}")
end

#a?Boolean

Checks whether the ip address belongs to a RFC 791 CLASS A network, no matter what the subnet mask is.

Example:

ip = IPAddress("10.0.0.1/24")

ip.a?
  #=> true

Returns:

  • (Boolean)

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# File 'lib/ipaddress/ipv4.rb', line 861

def a?
  CLASSFUL.key(8) === bits
end

#addressObject

Returns the address portion of the IPv4 object as a string.

ip = IPAddress("172.16.100.4/22")

ip.address
  #=> "172.16.100.4"

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# File 'lib/ipaddress/ipv4.rb', line 105

def address
  @address
end

#allocate(skip = 0) ⇒ Object

Allocates a new ip from the current subnet. Optional skip parameter can be used to skip addresses.

Will raise StopIteration exception when all addresses have been allocated

Example:

ip = IPAddress("10.0.0.0/24")
ip.allocate
  #=> "10.0.0.1/24"
ip.allocate
  #=> "10.0.0.2/24"
ip.allocate(2)
  #=> "10.0.0.5/24"

Uses an internal @allocator which tracks the state of allocated addresses.


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# File 'lib/ipaddress/ipv4.rb', line 1103

def allocate(skip=0)
    @allocator += 1 + skip

    next_ip = network_u32+@allocator
    if next_ip > broadcast_u32+1
        raise StopIteration
    end
    self.class.parse_u32(network_u32+@allocator, @prefix)
end

#b?Boolean

Checks whether the ip address belongs to a RFC 791 CLASS B network, no matter what the subnet mask is.

Example:

ip = IPAddress("172.16.10.1/24")

ip.b?
  #=> true

Returns:

  • (Boolean)

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# File 'lib/ipaddress/ipv4.rb', line 877

def b?
  CLASSFUL.key(16) === bits
end

#bitsObject

Returns the address portion of an IP in binary format, as a string containing a sequence of 0 and 1

ip = IPAddress("127.0.0.1")

ip.bits
  #=> "01111111000000000000000000000001"

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# File 'lib/ipaddress/ipv4.rb', line 316

def bits
  data.unpack("B*").first
end

#broadcastObject

Returns the broadcast address for the given IP.

ip = IPAddress("172.16.10.64/24")

ip.broadcast.to_s
  #=> "172.16.10.255"

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# File 'lib/ipaddress/ipv4.rb', line 328

def broadcast
  case
  when prefix <= 30
    self.class.parse_u32(broadcast_u32, @prefix)
  when prefix == 31
    self.class.parse_u32(-1, @prefix)
  when prefix == 32
    return self
  end
end

#broadcast_u32Object

Returns the broadcast address in Unsigned 32bits format

ip = IPaddress("10.0.0.1/29")

ip.broadcast_u32
  #=> 167772167

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# File 'lib/ipaddress/ipv4.rb', line 571

def broadcast_u32
  network_u32 + size - 1
end

#c?Boolean

Checks whether the ip address belongs to a RFC 791 CLASS C network, no matter what the subnet mask is.

Example:

ip = IPAddress("192.168.1.1/30")

ip.c?
  #=> true

Returns:

  • (Boolean)

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# File 'lib/ipaddress/ipv4.rb', line 893

def c?
  CLASSFUL.key(24) === bits
end

#dataObject

Returns the address portion of an IPv4 object in a network byte order format.

ip = IPAddress("172.16.10.1/24")

ip.data
  #=> "\254\020\n\001"

It is usually used to include an IP address in a data packet to be sent over a socket

a = Socket.open(params) # socket details here
ip = IPAddress("10.1.1.0/24")
binary_data = ["Address: "].pack("a*") + ip.data 

# Send binary data
a.puts binary_data

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# File 'lib/ipaddress/ipv4.rb', line 269

def data
  [@u32].pack("N")
end

#eachObject

Iterates over all the IP addresses for the given network (or IP address).

The object yielded is a new IPv4 object created from the iteration.

ip = IPAddress("10.0.0.1/29")

ip.each do |i|
  p i.address
end
  #=> "10.0.0.0"
  #=> "10.0.0.1"
  #=> "10.0.0.2"
  #=> "10.0.0.3"
  #=> "10.0.0.4"
  #=> "10.0.0.5"
  #=> "10.0.0.6"
  #=> "10.0.0.7"

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# File 'lib/ipaddress/ipv4.rb', line 475

def each
  (network_u32..broadcast_u32).each do |i|
    yield self.class.parse_u32(i, @prefix)
  end
end

#each_hostObject

Iterates over all the hosts IP addresses for the given network (or IP address).

ip = IPAddress("10.0.0.1/29")

ip.each_host do |i|
  p i.to_s
end
  #=> "10.0.0.1"
  #=> "10.0.0.2"
  #=> "10.0.0.3"
  #=> "10.0.0.4"
  #=> "10.0.0.5"
  #=> "10.0.0.6"

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# File 'lib/ipaddress/ipv4.rb', line 448

def each_host
  (network_u32+1..broadcast_u32-1).each do |i|
    yield self.class.parse_u32(i, @prefix)
  end
end

#firstObject

Returns a new IPv4 object with the first host IP address in the range.

Example: given the 192.168.100.0/24 network, the first host IP address is 192.168.100.1.

ip = IPAddress("192.168.100.0/24")

ip.first.to_s
  #=> "192.168.100.1"

The object IP doesn't need to be a network: the method automatically gets the network number from it

ip = IPAddress("192.168.100.50/24")

ip.first.to_s
  #=> "192.168.100.1"

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# File 'lib/ipaddress/ipv4.rb', line 389

def first
  case
  when prefix <= 30
    self.class.parse_u32(network_u32+1, @prefix)
  when prefix == 31
    self.class.parse_u32(network_u32, @prefix)
  when prefix == 32
    return self
  end
end

#hex(space = true) ⇒ Object Also known as: to_h, to_hex

Returns the address portion in hex

ip = IPAddress("10.0.0.0")

ip.to_h
  #=> 0a000000

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# File 'lib/ipaddress/ipv4.rb', line 244

def hex(space=true)
  "%.4x%.4x" % [to_u32].pack("N").unpack("nn")
end

#hostsObject

Returns an array with the IP addresses of all the hosts in the network.

ip = IPAddress("10.0.0.1/29")

ip.hosts.map {|i| i.address}
  #=> ["10.0.0.1",
  #=>  "10.0.0.2",
  #=>  "10.0.0.3",
  #=>  "10.0.0.4",
  #=>  "10.0.0.5",
  #=>  "10.0.0.6"]

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# File 'lib/ipaddress/ipv4.rb', line 547

def hosts
  to_a[1..-2]
end

#include?(oth) ⇒ Boolean

Checks whether a subnet includes the given IP address.

Accepts an IPAddress::IPv4 object.

ip = IPAddress("192.168.10.100/24")

addr = IPAddress("192.168.10.102/24")

ip.include? addr
  #=> true

ip.include? IPAddress("172.16.0.48/16")
  #=> false

Returns:

  • (Boolean)

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# File 'lib/ipaddress/ipv4.rb', line 590

def include?(oth)
  @prefix <= oth.prefix and network_u32 == (oth.to_u32 & @prefix.to_u32)
end

#include_all?(*others) ⇒ Boolean

Checks whether a subnet includes all the given IPv4 objects.

ip = IPAddress("192.168.10.100/24")

addr1 = IPAddress("192.168.10.102/24")
addr2 = IPAddress("192.168.10.103/24")

ip.include_all?(addr1,addr2)
  #=> true

Returns:

  • (Boolean)

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# File 'lib/ipaddress/ipv4.rb', line 606

def include_all?(*others)
  others.all? {|oth| include?(oth)}
end

#lastObject

Like its sibling method IPv4#first, this method returns a new IPv4 object with the last host IP address in the range.

Example: given the 192.168.100.0/24 network, the last host IP address is 192.168.100.254

ip = IPAddress("192.168.100.0/24")

ip.last.to_s
  #=> "192.168.100.254"

The object IP doesn't need to be a network: the method automatically gets the network number from it

ip = IPAddress("192.168.100.50/24")

ip.last.to_s
  #=> "192.168.100.254"

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# File 'lib/ipaddress/ipv4.rb', line 421

def last
  case
  when prefix <= 30
    self.class.parse_u32(broadcast_u32-1, @prefix)
  when prefix == 31
    self.class.parse_u32(broadcast_u32, @prefix)
  when prefix == 32
    return self
  end
end

Checks if an IPv4 address objects belongs to a link-local network RFC3927

Example:

ip = IPAddress "169.254.0.1"
ip.link_local?
  #=> true

Returns:

  • (Boolean)

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# File 'lib/ipaddress/ipv4.rb', line 664

def link_local?
  [self.class.new("169.254.0.0/16")].any? {|i| i.include? self}
end

#loopback?Boolean

Checks if an IPv4 address objects belongs to a loopback network RFC1122

Example:

ip = IPAddress "127.0.0.1"
ip.loopback?
  #=> true

Returns:

  • (Boolean)

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# File 'lib/ipaddress/ipv4.rb', line 650

def loopback?
  [self.class.new("127.0.0.0/8")].any? {|i| i.include? self}
end

#multicast?Boolean

Checks if an IPv4 address objects belongs to a multicast network RFC3171

Example:

ip = IPAddress "224.0.0.0/4"
ip.multicast?
  #=> true

Returns:

  • (Boolean)

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# File 'lib/ipaddress/ipv4.rb', line 636

def multicast?
  [self.class.new("224.0.0.0/4")].any? {|i| i.include? self}
end

#netmaskObject

Returns the prefix as a string in IP format

ip = IPAddress("172.16.100.4/22")

ip.netmask
  #=> "255.255.252.0"

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# File 'lib/ipaddress/ipv4.rb', line 193

def netmask
  @prefix.to_ip
end

#netmask=(addr) ⇒ Object

Like IPv4#prefix=, this method allow you to change the prefix / netmask of an IP address object.

ip = IPAddress("172.16.100.4")

puts ip
  #=> 172.16.100.4/16

ip.netmask = "255.255.252.0"

puts ip
  #=> 172.16.100.4/22

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# File 'lib/ipaddress/ipv4.rb', line 212

def netmask=(addr)
  @prefix = Prefix32.parse_netmask(addr)
end

#networkObject

Returns a new IPv4 object with the network number for the given IP.

ip = IPAddress("172.16.10.64/24")

ip.network.to_s
  #=> "172.16.10.0"

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# File 'lib/ipaddress/ipv4.rb', line 365

def network
  self.class.parse_u32(network_u32, @prefix)
end

#network?Boolean

Checks if the IP address is actually a network

ip = IPAddress("172.16.10.64/24")

ip.network?
  #=> false

ip = IPAddress("172.16.10.64/26")

ip.network?
  #=> true

Returns:

  • (Boolean)

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# File 'lib/ipaddress/ipv4.rb', line 352

def network?
  (@prefix < 32) && (@u32 | @prefix.to_u32 == @prefix.to_u32)
end

#network_u32Object

Returns the network number in Unsigned 32bits format

ip = IPAddress("10.0.0.1/29")

ip.network_u32
  #=> 167772160

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# File 'lib/ipaddress/ipv4.rb', line 559

def network_u32
  @u32 & @prefix.to_u32
end

#octetsObject

Returns the address as an array of decimal values

ip = IPAddress("172.16.100.4")

ip.octets
  #=> [172, 16, 100, 4]

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# File 'lib/ipaddress/ipv4.rb', line 155

def octets
  @octets
end

#prefixObject

Returns the prefix portion of the IPv4 object as a IPAddress::Prefix32 object

ip = IPAddress("172.16.100.4/22")

ip.prefix
  #=> 22

ip.prefix.class
  #=> IPAddress::Prefix32

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# File 'lib/ipaddress/ipv4.rb', line 121

def prefix
  @prefix
end

#prefix=(num) ⇒ Object

Set a new prefix number for the object

This is useful if you want to change the prefix to an object created with IPv4::parse_u32 or if the object was created using the classful mask.

ip = IPAddress("172.16.100.4")

puts ip
  #=> 172.16.100.4/16

ip.prefix = 22

puts ip
  #=> 172.16.100.4/22

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# File 'lib/ipaddress/ipv4.rb', line 143

def prefix=(num)
  @prefix = Prefix32.new(num)
end

#private?Boolean

Checks if an IPv4 address objects belongs to a private network RFC1918

Example:

ip = IPAddress "10.1.1.1/24"
ip.private?
  #=> true

Returns:

  • (Boolean)

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# File 'lib/ipaddress/ipv4.rb', line 620

def private?
  [self.class.new("10.0.0.0/8"),
   self.class.new("172.16.0.0/12"),
   self.class.new("192.168.0.0/16")].any? {|i| i.include? self}
end

#reverseObject Also known as: arpa

Returns the IP address in in-addr.arpa format for DNS lookups

ip = IPAddress("172.16.100.50/24")

ip.reverse
  #=> "50.100.16.172.in-addr.arpa"

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# File 'lib/ipaddress/ipv4.rb', line 677

def reverse
  @octets.reverse.join(".") + ".in-addr.arpa"
end

#sizeObject

Returns the number of IP addresses included in the network. It also counts the network address and the broadcast address.

ip = IPAddress("10.0.0.1/29")

ip.size
  #=> 8

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# File 'lib/ipaddress/ipv4.rb', line 529

def size
  2 ** @prefix.host_prefix
end

#split(subnets = 2) ⇒ Object Also known as: /

Splits a network into different subnets

If the IP Address is a network, it can be divided into multiple networks. If self is not a network, this method will calculate the network from the IP and then subnet it.

If subnets is an power of two number, the resulting networks will be divided evenly from the supernet.

network = IPAddress("172.16.10.0/24")

network / 4   # implies map{|i| i.to_string}
  #=> ["172.16.10.0/26",
  #=>  "172.16.10.64/26",
  #=>  "172.16.10.128/26",
  #=>  "172.16.10.192/26"]

If num is any other number, the supernet will be divided into some networks with a even number of hosts and other networks with the remaining addresses.

network = IPAddress("172.16.10.0/24")

network / 3   # implies map{|i| i.to_string}
  #=> ["172.16.10.0/26",
  #=>  "172.16.10.64/26",
  #=>  "172.16.10.128/25"]

Returns an array of IPv4 objects


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# File 'lib/ipaddress/ipv4.rb', line 734

def split(subnets=2)
  unless (1..(2**@prefix.host_prefix)).include? subnets
    raise ArgumentError, "Value #{subnets} out of range" 
  end
  networks = subnet(newprefix(subnets))
  until networks.size == subnets
    networks = sum_first_found(networks)
  end
  return networks
end

#subnet(subprefix) ⇒ Object

This method implements the subnetting function similar to the one described in RFC3531.

By specifying a new prefix, the method calculates the network number for the given IPv4 object and calculates the subnets associated to the new prefix.

For example, given the following network:

ip = IPAddress "172.16.10.0/24"

we can calculate the subnets with a /26 prefix

ip.subnet(26).map{&:to_string)
  #=> ["172.16.10.0/26", "172.16.10.64/26", 
       "172.16.10.128/26", "172.16.10.192/26"]

The resulting number of subnets will of course always be a power of two.


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# File 'lib/ipaddress/ipv4.rb', line 798

def subnet(subprefix)
  unless ((@prefix.to_i)..32).include? subprefix
    raise ArgumentError, "New prefix must be between #@prefix and 32"
  end
  Array.new(2**(subprefix-@prefix.to_i)) do |i|
    self.class.parse_u32(network_u32+(i*(2**(32-subprefix))), subprefix)
  end
end

#supernet(new_prefix) ⇒ Object

Returns a new IPv4 object from the supernetting of the instance network.

Supernetting is similar to subnetting, except that you getting as a result a network with a smaller prefix (bigger host space). For example, given the network

ip = IPAddress("172.16.10.0/24")

you can supernet it with a new /23 prefix

ip.supernet(23).to_string
  #=> "172.16.10.0/23"

However if you supernet it with a /22 prefix, the network address will change:

ip.supernet(22).to_string
  #=> "172.16.8.0/22"

If new_prefix is less than 1, returns 0.0.0.0/0

Raises:

  • (ArgumentError)

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# File 'lib/ipaddress/ipv4.rb', line 770

def supernet(new_prefix)
  raise ArgumentError, "New prefix must be smaller than existing prefix" if new_prefix >= @prefix.to_i
  return self.class.new("0.0.0.0/0") if new_prefix < 1
  return self.class.new(@address+"/#{new_prefix}").network
end

#to(e) ⇒ Object

Return a list of IP's between @address and the supplied IP

ip = IPAddress("172.16.100.51/32")

ip.to("172.16.100.100")
  #=> ["172.16.100.51",
  #=>  "172.16.100.52",
  #=>  ...
  #=>  "172.16.100.99",
  #=>  "172.16.100.100"]

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# File 'lib/ipaddress/ipv4.rb', line 695

def to(e)
  unless e.is_a? IPAddress::IPv4
    e = IPv4.new(e)
  end

  Range.new(@u32, e.to_u32).map{|i| IPAddress.ntoa(i) }
end

#to_ipv6Object

Return the ip address in a format compatible with the IPv6 Mapped IPv4 addresses

Example:

ip = IPAddress("172.16.10.1/24")

ip.to_ipv6
  #=> "ac10:0a01"

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# File 'lib/ipaddress/ipv4.rb', line 908

def to_ipv6
  "%.4x:%.4x" % [to_u32].pack("N").unpack("nn")
end

#to_sObject

Returns a string with the address portion of the IPv4 object

ip = IPAddress("172.16.100.4/22")

ip.to_s
  #=> "172.16.100.4"

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# File 'lib/ipaddress/ipv4.rb', line 168

def to_s
  @address
end

#to_stringObject

Returns a string with the IP address in canonical form.

ip = IPAddress("172.16.100.4/22")

ip.to_string
  #=> "172.16.100.4/22"

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# File 'lib/ipaddress/ipv4.rb', line 181

def to_string
  "#@address/#@prefix"
end

#u32Object Also known as: to_i, to_u32

Returns the address portion in unsigned 32 bits integer format.

This method is identical to the C function inet_pton to create a 32 bits address family structure.

ip = IPAddress("10.0.0.0/8")

ip.to_i
  #=> 167772160

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# File 'lib/ipaddress/ipv4.rb', line 229

def u32
  @u32
end