Module:IP: Difference between revisions

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m (comment and variable tweaks)
(add more methods to RawIP and rework IPAddress and Subnet to use them)
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-- Load modules
-- Load modules
require('Module:No globals')
local bit32 = require('bit32')
local bit32 = require('bit32')
local libraryUtil = require('libraryUtil')
local libraryUtil = require('libraryUtil')
Line 45: Line 46:
-- Constructors
-- Constructors
function RawIP.newFromIPv4(ipStr)
function RawIP.newFromIPv4(ipStr)
-- If ipStr is a valid IPv4 string, return a collection of its parts.
-- Returns a RawIP object if ipStr is a valid IPv4 string. Otherwise,
-- Otherwise, return nil.
-- returns nil.
-- This representation is for compatibility with IPv6 addresses.
-- This representation is for compatibility with IPv6 addresses.
local octets = Collection()
local octets = Collection()
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parts[i] = num
parts[i] = num
else
else
return false
return nil
end
end
end
end
Line 107: Line 108:
end
end
return nil
return nil
end

function RawIP.newFromIP(ipStr)
-- Return a new RawIP object from either an IPv4 string or an IPv6
-- string. If ipStr is not a valid IPv4 or IPv6 string, then return
-- nil.
return RawIP.newFromIPv4(ipStr) or RawIP.newFromIPv6(ipStr)
end
end


-- Methods
-- Methods
function RawIP:getVersion()
return self.n == 2 and V4 or V6
end

function RawIP:isIPv4()
return self.n == 2
end

function RawIP:isIPv6()
return self.n == 8
end

function RawIP:getAdjacent(previous)
function RawIP:getAdjacent(previous)
-- Return a RawIP object for an adjacent IP address. If previous is true
-- Return a RawIP object for an adjacent IP address. If previous is true
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end
end
end
end
return setmetatable(result, rawIP)
return setmetatable(result, RawIP)
end
end


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--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
-- Set up classes to be exported
-- IPAddress class
-- Represents a single IPv4 or IPv6 address.
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------


-- The IPAddress class and the Subnet class should be accessible from each
local IPAddress = {}
-- other, but should not be accessible from the RawIP class, so initialize them
-- here.
local IPAddress, Subnet = {}, {}


-- IPAddress needs to create Subnet objects using its RawIP data, and Subnet
local newIPFromRaw
-- newIPFromRaw constructs a new IPAddress object from a rawIP object. It needs
-- needs to create IPAddress objects with its RawIP data as well. However,
-- other modules shouldn't have to worry about RawIP data, so the constructors
-- to be accessible from the Subnet class but it should not be public.
-- need to be private. Hence the variables holding the constructor functions
-- need to be initialized here as well.
local makeIPAddress, makeSubnet

--------------------------------------------------------------------------------
-- IPAddress class
-- Represents a single IPv4 or IPv6 address.
--------------------------------------------------------------------------------


do
do
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-- Constructors
-- Constructors
newIPFromRaw = function (rawIP)
makeIPAddress = function (rawIP)
-- Constructs a new IPAddress object from a rawIP object. This function
-- Constructs a new IPAddress object from a rawIP object. This function
-- is for internal use; it is called by IPAddress.new and from other
-- is for internal use; it is called by IPAddress.new and from other
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-- Set up structure
-- Set up structure
local obj = {}
local obj = {}
local data = {
local data = {}
rawIP = rawIP,
data.rawIP = rawIP
version = rawIP.n == 2 and V4 or V6,
}


-- Public methods
-- Public methods
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function obj:getVersion()
function obj:getVersion()
return data.version
return data.rawIP:getVersion()
end

function obj:getHighestIP(bitLength)
return newIPFromRaw(setHostBits(data.rawIP, bitLength))
end

function obj:getPrefix(bitLength)
return newIPFromRaw(copyPrefix(data.rawIP, bitLength))
end
end


function obj:isIPv4()
function obj:isIPv4()
return data.version == V4
return data.rawIP:isIPv4()
end
end


function obj:isIPv6()
function obj:isIPv6()
return data.version == V6
return data.rawIP:isIPv6()
end
end


function obj:isInSubnet(subnet)
function obj:isInSubnet(subnet)
return subnet:containsIP(self)
-- TODO Consider alternative of checking:
-- (ipFirst <= self and self <= ipLast)
if self:getVersion() == subnet:getVersion() then
local prefix = self:getPrefix(subnet:getBitLength())
return prefix == subnet:getPrefix()
end
return false
end
end


function obj:getNextIP()
function obj:getNextIP()
return newIPFromRaw(data.rawIP:getAdjacent())
return makeIPAddress(data.rawIP:getAdjacent())
end
end


function obj:getPreviousIP()
function obj:getPreviousIP()
return newIPFromRaw(data.rawIP:getAdjacent(true))
return makeIPAddress(data.rawIP:getAdjacent(true))
end
end


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function IPAddress.new(ip)
function IPAddress.new(ip)
checkType('IPAddress.new', 1, ip, 'string')
checkType('IPAddress.new', 1, ip, 'string')
local rawIP = RawIP.newFromIPv4String(ip) or RawIP.newFromIPv6String(ip)
local rawIP = RawIP.newFromIP(ip)
if not rawIP then
if not rawIP then
error('invalid IP', 2)
error(string.format("'%s' is an invalid IP", ip), 2)
end
end
return newIPFromRaw(rawIP)
return makeIPAddress(rawIP)
end
end
end

local function makeSubnet(data, cidrStr)
-- If cidrStr is a valid IPv4 or IPv6 CIDR specification, store its
-- information in data and return its version. Otherwise, return nil.
local lhs, rhs = cidrStr:match('^%s*(.-)/(%d+)%s*$')
if lhs then
local bits = lhs:find(':', 1, true) and 128 or 32
local n = tonumber(rhs)
if n and n <= bits then
local base = IPAddress.new(lhs)
local prefix = base:getPrefix(n)
if base == prefix then
data.bitLength = n
data.prefix = prefix
data.highestIP = base:getHighestIP(n)
return bits == 32 and V4 or V6
end
end
end
return nil
end
end


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-- Represents a block of IPv4 or IPv6 addresses.
-- Represents a block of IPv4 or IPv6 addresses.
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------

local Subnet = {}


do
do
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local mt = {}
local mt = {}


-- Constructor
-- Constructors
function Subnet.new(cidr)
makeSubnet = function (rawIP, bitLength)
-- Set up structure
-- Set up structure
local obj = setmetatable({}, mt)
local obj = setmetatable({}, mt)
local data = {}
local data = {
rawIP = rawIP,
bitLength = bitLength,
}


-- Public methods
-- Public methods
function obj:getPrefix()
function obj:getPrefix()
if not data.prefix then
data.prefix = makeIPAddress(
data.rawIP:getPrefix(data.bitLength)
)
end
return data.prefix
return data.prefix
end
end


function obj:getHighestIP()
function obj:getHighestIP()
if not data.highestIP then
data.highestIP = makeIPAddress(
data.rawIP:getHighestHost(data.bitLength)
)
end
return data.highestIP
return data.highestIP
end
end
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function obj:getCIDR()
function obj:getCIDR()
return string.format('%s/%d', self:getPrefix(), self:getBitLength())
return string.format(
'%s/%d',
tostring(self:getPrefix()), self:getBitLength()
)
end
end


function obj:getVersion()
function obj:getVersion()
return data.version
return data.rawIP:getVersion()
end
end


function obj:isIPv4()
function obj:isIPv4()
return data.version == V4
return data.rawIP:isIPv4()
end
end


function obj:isIPv6()
function obj:isIPv6()
return data.version == V6
return data.rawIP:isIPv6()
end
end


function obj:containsIP(ip)
function obj:containsIP(ip)
-- TODO See ip:isInSubnet(subnet); use this technique there?
if self:getVersion() == ip:getVersion() then
if self:getVersion() == ip:getVersion() then
return self:getPrefix() <= ip and ip <= self:getHighestIP()
return self:getPrefix() <= ip and ip <= self:getHighestIP()
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end
end


return obj
-- Set initial values
end

function Subnet.new(cidr)
checkType('Subnet.new', 1, cidr, 'string')
checkType('Subnet.new', 1, cidr, 'string')
local lhs, rhs = cidr:match('^%s*(.-)/(%d+)%s*$')
data.version = makeSubnet(data, cidr)
if not data.version then
if lhs then
local bits = lhs:find(':', 1, true) and 128 or 32
error('invalid CIDR', 2)
local n = tonumber(rhs)
if n and n <= bits then
local base = RawIP.newFromIP(lhs)
local prefix = base:getPrefix(n)
if base == prefix then
return makeSubnet(prefix, n)
end
end
end
end
error(string.format("'%s' is an invalid CIDR string", cidr), 2)

return obj
end
end


Revision as of 09:12, July 19, 2016

Module:IP is a library for working with IP addresses and subnets. It can handle both IPv4 and IPv6. The library exports four classes, IPAddress, Subnet, IPv4Collection, and IPv6Collection.

Loading the library

local IP = require('Module:IP')
local IPAddress = IP.IPAddress
local Subnet = IP.Subnet

IPAddress

The IPAddress class is used to work with single IP addresses. To create a new IPAddress object: 

local ipAddress = IPAddress.new(ipString)

The ipString variable can be a valid IPv4 or IPv6 address.

Examples: 

local ipv4Address = IPAddress.new('1.2.3.4')
local ipv6Address = IPAddress.new('2001:db8::ff00:12:3456')

IPAddress objects can be compared with relational operators: 

-- Equality
IPAddress.new('1.2.3.4') == IPAddress.new('1.2.3.4') -- true
IPAddress.new('1.2.3.4') == IPAddress.new('1.2.3.5') -- false

-- Less than / greater than
IPAddress.new('1.2.3.4') < IPAddress.new('1.2.3.5')  -- true
IPAddress.new('1.2.3.4') > IPAddress.new('1.2.3.5')  -- false
IPAddress.new('1.2.3.4') <= IPAddress.new('1.2.3.5') -- true
IPAddress.new('1.2.3.4') <= IPAddress.new('1.2.3.4') -- true

You can use tostring on them (this is equivalent to using getIP): 

tostring(IPAddress.new('1.2.3.4'))                -- "1.2.3.4"
tostring(IPAddress.new('2001:db8::ff00:12:3456')) -- "2001:db8::ff00:12:3456"

-- Expanded IPv6 addresses are abbreviated:
tostring(IPAddress.new('2001:db8:0:0:0:0:0:0'))   -- "2001:db8::"

You can also concatenate them: 

IPAddress.new('1.2.3.4') .. ' foo'                   -- "1.2.3.4 foo"
IPAddress.new('1.2.3.4') .. IPAddress.new('5.6.7.8') -- "1.2.3.45.6.7.8"

IPAddress objects have several methods, outlined below.

getIP

ipAddress:getIP()

Returns a string representation of the IP address. IPv6 addresses are abbreviated if possible.

Examples: 

IPAddress.new('1.2.3.4'):getIP()                -- "1.2.3.4"
IPAddress.new('2001:db8::ff00:12:3456'):getIP() -- "2001:db8::ff00:12:3456"
IPAddress.new('2001:db8:0:0:0:0:0:0'):getIP()   -- "2001:db8::"

getVersion

ipAddress:getVersion()

Returns the version of the IP protocol being used. This is "IPv4" for IPv4 addresses, and "IPv6" for IPv6 addresses.

Examples: 

IPAddress.new('1.2.3.4'):getVersion()                -- "IPv4"
IPAddress.new('2001:db8::ff00:12:3456'):getVersion() -- "IPv6"

isIPv4

ipAddress:isIPv4()

Returns true if the IP address is an IPv4 address, and false otherwise.

Examples: 

IPAddress.new('1.2.3.4'):isIPv4()                -- true
IPAddress.new('2001:db8::ff00:12:3456'):isIPv4() -- false

isIPv6

ipAddress:isIPv6()

Returns true if the IP address is an IPv6 address, and false otherwise.

Examples: 

IPAddress.new('1.2.3.4'):isIPv6()                -- false
IPAddress.new('2001:db8::ff00:12:3456'):isIPv6() -- true

isInSubnet

ipAddress:isInSubnet(subnet)

Returns true if the IP address is in the subnet subnet, and false otherwise. subnet may be a Subnet object or a CIDR string.

Examples: 

IPAddress.new('1.2.3.4'):isInSubnet('1.2.3.0/24')                             -- true
IPAddress.new('1.2.3.4'):isInSubnet('1.2.4.0/24')                             -- false
IPAddress.new('1.2.3.4'):isInSubnet(Subnet.new('1.2.3.0/24'))                 -- true
IPAddress.new('2001:db8::ff00:12:3456'):isInSubnet('2001:db8::ff00:12:0/112') -- true

getSubnet

ipAddress:getSubnet(bitLength)

Returns a Subnet object for the subnet with a bit length of bitLength which contains the current IP. The bitLength parameter must be an integer between 0 and 32 for IPv4 addresses, or an integer between 0 and 128 for IPv6 addresses.

Examples: 

IPAddress.new('1.2.3.4'):getSubnet(24) -- Equivalent to Subnet.new('1.2.3.0/24')

getNextIP

ipAddress:getNextIP()

Returns a new IPAddress object equivalent to the current IP address incremented by one. The IPv4 address "255.255.255.255" rolls around to "0.0.0.0", and the IPv6 address "ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff" rolls around to "::".

Examples: 

IPAddress.new('1.2.3.4'):getNextIP()                -- Equivalent to IPAddress.new('1.2.3.5')
IPAddress.new('2001:db8::ff00:12:3456'):getNextIP() -- Equivalent to IPAddress.new('2001:db8::ff00:12:3457')
IPAddress.new('255.255.255.255'):getNextIP()        -- Equivalent to IPAddress.new('0.0.0.0')

getPreviousIP

ipAddress:getPreviousIP()

Returns a new IPAddress object equivalent to the current IP address decremented by one. The IPv4 address "0.0.0.0" rolls around to "255.255.255.255", and the IPv6 address "::" rolls around to "ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff".

Examples: 

IPAddress.new('1.2.3.4'):getPreviousIP()                -- Equivalent to IPAddress.new('1.2.3.3')
IPAddress.new('2001:db8::ff00:12:3456'):getPreviousIP() -- Equivalent to IPAddress.new('2001:db8::ff00:12:3455')
IPAddress.new('0.0.0.0'):getPreviousIP()                -- Equivalent to IPAddress.new('255.255.255.255')

Subnet

The Subnet class is used to work with subnetworks of IPv4 or IPv6 addresses. To create a new Subnet object: 

local subnet = Subnet.new(cidrString)

cidrString must be a valid IPv4 or IPv6 CIDR string.

Subnet objects can be compared for equality: 

Subnet.new('1.2.3.0/24') == Subnet.new('1.2.3.0/24')                           -- true
Subnet.new('1.2.3.0/24') == Subnet.new('1.2.3.0/25')                           -- false
Subnet.new('1.2.3.0/24') == Subnet.new('2001:db8::ff00:12:0/112')              -- false
Subnet.new('2001:db8::ff00:12:0/112') == Subnet.new('2001:db8::ff00:12:0/112') -- true
Subnet.new('2001:db8:0:0:0:0:0:0/112') == Subnet.new('2001:db8::/112')         -- true

You can use tostring on them (this is equivalent to getCIDR): 

tostring(Subnet.new('1.2.3.0/24'))               -- "1.2.3.0/24"
tostring(Subnet.new('2001:db8::ff00:12:0/112'))  -- "2001:db8::ff00:12:0/112"
tostring(Subnet.new('2001:db8:0:0:0:0:0:0/112')) -- "2001:db8::/112"

You can also concatenate them: 

Subnet.new('1.2.3.0/24') .. ' foo'                   -- "1.2.3.0/24 foo"
Subnet.new('1.2.3.0/24') .. Subnet.new('4.5.6.0/24') -- "1.2.3.0/244.5.6.0/24"

Subnet objects have several methods, outlined below.

getPrefix

subnet:getPrefix()

Returns an IPAddress object for the lowest IP address in the subnet.

Examples: 

Subnet.new('1.2.3.0/24'):getPrefix()              -- Equivalent to IPAddress.new('1.2.3.0')
Subnet.new('2001:db8::ff00:12:0/112'):getPrefix() -- Equivalent to IPAddress.new('2001:db8::ff00:12:0')

getHighestIP

subnet:getHighestIP()

Returns an IPAddress object for the highest IP address in the subnet.

Examples: 

Subnet.new('1.2.3.0/24'):getHighestIP()              -- Equivalent to IPAddress.new('1.2.3.255')
Subnet.new('2001:db8::ff00:12:0/112'):getHighestIP() -- Equivalent to IPAddress.new('2001:db8::ff00:12:ffff')

getBitLength

subnet:getBitLength()

Returns the bit length of the subnet. This is an integer between 0 and 32 for IPv4 addresses, or an integer between 0 and 128 for IPv6 addresses.

Examples: 

Subnet.new('1.2.3.0/24'):getBitLength()              -- 24
Subnet.new('2001:db8::ff00:12:0/112'):getBitLength() -- 112

getCIDR

subnet:getCIDR()

Returns a CIDR string representation of the subnet.

Examples: 

Subnet.new('1.2.3.0/24'):getCIDR()               -- "1.2.3.0/24"
Subnet.new('2001:db8::ff00:12:0/112'):getCIDR()  -- "2001:db8::ff00:12:0/112"
Subnet.new('2001:db8:0:0:0:0:0:0/112'):getCIDR() -- "2001:db8::/112"

getVersion

subnet:getVersion()

Returns the version of the IP protocol being used. This is "IPv4" for IPv4 addresses, and "IPv6" for IPv6 addresses.

Examples: 

Subnet.new('1.2.3.0/24'):getVersion()              -- "IPv4"
Subnet.new('2001:db8::ff00:12:0/112'):getVersion() -- "IPv6"

isIPv4

subnet:isIPv4()

Returns true if the subnet is using IPv4, and false otherwise.

Examples: 

Subnet.new('1.2.3.0/24'):isIPv4()              -- true
Subnet.new('2001:db8::ff00:12:0/112'):isIPv4() -- false

isIPv6

subnet:isIPv6()

Returns true if the subnet is using IPv6, and false otherwise.

Examples: 

Subnet.new('1.2.3.0/24'):isIPv6()              -- false
Subnet.new('2001:db8::ff00:12:0/112'):isIPv6() -- true

containsIP

subnet:containsIP(ip)

Returns true if the subnet contains the IP address ip, and false otherwise. ip can be an IP address string, or an IPAddress object.

Examples: 

Subnet.new('1.2.3.0/24'):containsIP('1.2.3.4')                             -- true
Subnet.new('1.2.3.0/24'):containsIP('1.2.4.4')                             -- false
Subnet.new('1.2.3.0/24'):containsIP(IPAddress.new('1.2.3.4'))              -- true
Subnet.new('2001:db8::ff00:12:0/112'):containsIP('2001:db8::ff00:12:3456') -- true

overlapsSubnet

subnet:overlapsSubnet(subnet)

Returns true if the current subnet overlaps with subnet, and false otherwise. subnet can be a CIDR string or a subnet object.

Examples: 

Subnet.new('1.2.3.0/24'):overlapsSubnet('1.2.0.0/16')                         -- true
Subnet.new('1.2.3.0/24'):overlapsSubnet('1.2.12.0/22')                        -- false
Subnet.new('1.2.3.0/24'):overlapsSubnet(Subnet.new('1.2.0.0/16'))             -- true
Subnet.new('2001:db8::ff00:12:0/112'):overlapsSubnet('2001:db8::ff00:0:0/96') -- true

walk

subnet:walk()

The walk method iterates over all of the IPAddress objects in the subnet.

Examples: 

for ipAddress in Subnet.new('192.168.0.0/30'):walk() do
	mw.log(tostring(ipAddress))
end
-- 192.168.0.0
-- 192.168.0.1
-- 192.168.0.2
-- 192.168.0.3

IPv4Collection

The IPv4Collection class is used to work with several different IPv4 addresses and IPv4 subnets. To create a new IPv4Collection object: 

local collection = IPv4Collection.new()

IPv4Collection objects have several methods, outlined below.

getVersion

collection:getVersion()

Returns the string "IPv4".

addIP

collection:addIP(ip)

Adds an IP to the collection. The IP can be either a string or an IPAddress object.

Examples: 

collection:addIP('1.2.3.4')
collection:addIP(IPAddress.new('1.2.3.4'))

This method is chainable: 

collection:addIP('1.2.3.4'):addIP('5.6.7.8')

addSubnet

collection:addSubnet(subnet)

Adds a subnet to the collection. The subnet can be either a CIDR string or a Subnet object.

Examples: 

collection:addSubnet('1.2.3.0/24')
collection:addSubnet(Subnet.new('1.2.3.0/24'))

This method is chainable: 

collection:addSubnet('1.2.0.0/24'):addSubnet('1.2.1.0/24')

addFromString

collection:addFromString(str)

Extracts any IPv4 addresses and IPv4 CIDR subnets from str and adds them to the collection. Any text that is not an IPv4 address or CIDR subnet is ignored.

Examples: 

collection:addFromString('Add some IPs and subnets: 1.2.3.4 1.2.3.5 2001:0::f foo 1.2.4.0/24')

This method is chainable: 

collection:addFromString('foo 1.2.3.4'):addFromString('bar 5.6.7.8')

containsIP

collection:containsIP(ip)

Returns true if the collection contains the specified IP; otherwise returns false. The ip parameter can be a string or an IPAddress object.

Examples: 

collection:containsIP('1.2.3.4')
collection:containsIP(IPAddress.new('1.2.3.4'))

getRanges

collection:getRanges()

Returns a sorted array of IP pairs equivalent to the collection. Each IP pair is an array representing a contiguous range of IP addresses from pair[1] to pair[2] inclusive. pair[1] and pair[2] are IPAddress objects.

Examples: 

collection:addSubnet('1.2.0.0/24')
collection:addSubnet('1.2.1.0/24')
collection:addSubnet('1.2.10.0/24')
mw.logObject(collection:getRanges())
-- Logs the following:
-- table#1 {
--   table#2 {
--     1.2.0.0,
--     1.2.1.255,
--   },
--   table#3 {
--     1.2.10.0,
--     1.2.10.255,
--   },
-- }

overlapsSubnet

collection:overlapsSubnet(subnet)

Returns true, obj if subnet overlaps this collection, where obj is the first IPAddress or Subnet object overlapping the subnet. Otherwise, returns false. subnet can be a CIDR string or a Subnet object.

Examples: 

collection:addIP('1.2.3.4')
collection:overlapsSubnet('1.2.3.0/24') -- true, IPAddress.new('1.2.3.4')
collection:overlapsSubnet('1.2.4.0/24') -- false

IPv6Collection

The IPv6Collection class is used to work with several different IPv6 addresses and IPv6 subnets. IPv6Collection objects are directly analogous to IPv4Collection objects: they contain the same methods and work the same way, but all IP addresses and subnets added to it must be IPv6, not IPv4.

To create a new IPv6Collection object: 

local collection = IPv6Collection.new()



-- IP library
-- This library contains classes for working with IP addresses and IP ranges.

-- Load modules
require('Module:No globals')
local bit32 = require('bit32')
local libraryUtil = require('libraryUtil')
local checkType = libraryUtil.checkType

-- Constants
local V4 = 'IPv4'
local V6 = 'IPv6'

--------------------------------------------------------------------------------
-- RawIP class
-- Numeric representation of an IPv4 or IPv6 address. Used internally.
-- A RawIP object is constructed by adding data to a Collection object and
-- then giving it a new metatable. This is to avoid the memory overhead of
-- copying the data to a new table.
--------------------------------------------------------------------------------

local RawIP = {}
RawIP.__index = RawIP

do
	-- Collection class.
	-- This is a table used to hold items.
	local Collection
	do
		local mt = {
			__index = {
				add = function (self, item)
					self.n = self.n + 1
					self[self.n] = item
				end,
				join = function (self, sep)
					return table.concat(self, sep)
				end,
			}
		}
		Collection = function ()
			return setmetatable({n = 0}, mt)
		end
	end

	-- Constructors
	function RawIP.newFromIPv4(ipStr)
		-- Returns a RawIP object if ipStr is a valid IPv4 string. Otherwise,
		-- returns nil.
		-- This representation is for compatibility with IPv6 addresses.
		local octets = Collection()
		local s = ipStr:match('^%s*(.-)%s*$') .. '.'
		for item in s:gmatch('(.-)%.') do
			octets:add(item)
		end
		if octets.n == 4 then
			for i, s in ipairs(octets) do
				if s:match('^%d+$') then
					local num = tonumber(s)
					if 0 <= num and num <= 255 then
						if num > 0 and s:match('^0') then
							-- A redundant leading zero is for an IP in octal.
							return false
						end
						octets[i] = num
					else
						return false
					end
				else
					return false
				end
			end
			local parts = Collection()
			for i = 1, 3, 2 do
				parts:add(octets[i] * 256 + octets[i+1])
			end
			return setmetatable(parts, RawIP)
		end
		return nil
	end
	
	function RawIP.newFromIPv6(ipStr)
		-- If ipStr is a valid IPv6 string, return a collection of its parts.
		-- Otherwise, return nil.
		ipStr = ipStr:match('^%s*(.-)%s*$')
		local _, n = ipStr:gsub(':', ':')
		if n < 7 then
			ipStr, n = ipStr:gsub('::', string.rep(':', 9 - n))
		end
		local parts = Collection()
		for item in (ipStr .. ':'):gmatch('(.-):') do
			parts:add(item)
		end
		if parts.n == 8 then
			for i, s in ipairs(parts) do
				if s == '' then
					parts[i] = 0
				else
					local num = tonumber('0x' .. s)
					if num and 0 <= num and num <= 65535 then
						parts[i] = num
					else
						return nil
					end
				end
			end
			return setmetatable(parts, RawIP)
		end
		return nil
	end

	function RawIP.newFromIP(ipStr)
		-- Return a new RawIP object from either an IPv4 string or an IPv6
		-- string. If ipStr is not a valid IPv4 or IPv6 string, then return
		-- nil.
		return RawIP.newFromIPv4(ipStr) or RawIP.newFromIPv6(ipStr)
	end

	-- Methods
	function RawIP:getVersion()
		return self.n == 2 and V4 or V6
	end

	function RawIP:isIPv4()
		return self.n == 2
	end

	function RawIP:isIPv6()
		return self.n == 8
	end

	function RawIP:getAdjacent(previous)
		-- Return a RawIP object for an adjacent IP address. If previous is true
		-- then the previous IP is returned; otherwise the next IP is returned.
		-- Will wraparound:
		--   next      255.255.255.255 → 0.0.0.0
		--             ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff → ::
		--   previous  0.0.0.0 → 255.255.255.255
		--             :: → ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff
		local result = Collection()
		result.n = self.n
		local carry = down and 0xffff or 1
		for i = self.n, 1, -1 do
			local sum = self[i] + carry
			if sum >= 0x10000 then
				carry = down and 0x10000 or 1
				sum = sum - 0x10000
			else
				carry = down and 0xffff or 0
			end
			result[i] = sum
		end
		return setmetatable(result, RawIP)
	end

	function RawIP:getPrefix(bitLength)
		-- Return a RawIP object for the prefix of the current IP Address with a
		-- bit length of bitLength.
		local result = Collection()
		result.n = self.n
		for i = 1, self.n do
			if bitLength > 0 then
				if bitLength >= 16 then
					result[i] = self[i]
					bitLength = bitLength - 16
				else
					result[i] = bit32.band(self[i],
						bit32.arshift(0xffff8000, bitLength - 1))
					bitLength = 0
				end
			else
				result[i] = 0
			end
		end
		return setmetatable(result, RawIP)
	end

	function RawIP:getHighestHost(bitLength)
		-- Return a RawIP object for the highest IP with the prefix of length
		-- bitLength. In other words, the network (the most-significant bits)
		-- is the same as the current IP's, but the host bits (the
		-- least-significant bits) are all set to 1.
		local bits = self.n * 16
		local width
		if bitLength <= 0 then
			width = bits
		elseif bitLength >= bits then
			width = 0
		else
			width = bits - bitLength
		end
		local result = Collection()
		result.n = self.n
		for i = self.n, 1, -1 do
			if width > 0 then
				if width >= 16 then
					result[i] = 0xffff
					width = width - 16
				else
					result[i] = bit32.replace(self[i], 0xffff, width - 1, width)
					width = 0
				end
			else
				result[i] = self[i]
			end
		end
		return setmetatable(result, RawIP)
	end

	function RawIP:_makeIPv6String()
		-- Return an IPv6 string representation of the object. Behavior is undefined
		-- if the current object is IPv4.
		local z1, z2  -- indices of run of zeros to be displayed as "::"
		local zstart, zcount
		for i = 1, 9 do
			-- Find left-most occurrence of longest run of two or more zeros.
			if i < 9 and self[i] == 0 then
				if zstart then
					zcount = zcount + 1
				else
					zstart = i
					zcount = 1
				end
			else
				if zcount and zcount > 1 then
					if not z1 or zcount > z2 - z1 + 1 then
						z1 = zstart
						z2 = zstart + zcount - 1
					end
				end
				zstart = nil
				zcount = nil
			end
		end
		local parts = Collection()
		for i = 1, 8 do
			if z1 and z1 <= i and i <= z2 then
				if i == z1 then
					if z1 == 1 or z2 == 8 then
						if z1 == 1 and z2 == 8 then
							return '::'
						end
						parts:add(':')
					else
						parts:add('')
					end
				end
			else
				parts:add(string.format('%x', self[i]))
			end
		end
		return parts:join(':')
	end

	function RawIP:_makeIPv4String()
		-- Return an IPv4 string representation of the object. Behavior is undefined
		-- if the current object is IPv6.
		local parts = Collection()
		for i = 1, 2 do
			local w = self[i]
			parts:add(math.floor(w / 256))
			parts:add(w % 256)
		end
		return parts:join('.')
	end

	function RawIP:__tostring()
		-- Return a string equivalent to given IP address (IPv4 or IPv6).
		if self.n == 2 then
			return self:_makeIPv4String()
		else
			return self:_makeIPv6String()
		end
	end

	function RawIP:__lt(obj)
		if self.n == obj.n then
			for i = 1, self.n do
				if self[i] ~= obj[i] then
					return self[i] < obj[i]
				end
			end
			return false
		end
		return self.n < obj.n
	end

	function RawIP:__eq(obj)
		if self.n == obj.n then
			for i = 1, self.n do
				if self[i] ~= obj[i] then
					return false
				end
			end
			return true
		end
		return false
	end
end

--------------------------------------------------------------------------------
-- Set up classes to be exported
--------------------------------------------------------------------------------

-- The IPAddress class and the Subnet class should be accessible from each
-- other, but should not be accessible from the RawIP class, so initialize them
-- here.
local IPAddress, Subnet = {}, {}

-- IPAddress needs to create Subnet objects using its RawIP data, and Subnet
-- needs to create IPAddress objects with its RawIP data as well. However,
-- other modules shouldn't have to worry about RawIP data, so the constructors
-- need to be private. Hence the variables holding the constructor functions
-- need to be initialized here as well.
local makeIPAddress, makeSubnet

--------------------------------------------------------------------------------
-- IPAddress class
-- Represents a single IPv4 or IPv6 address.
--------------------------------------------------------------------------------

do
	local dataKey = {} -- A unique key to access objects' internal data.

	-- Metamethods that don't need upvalues
	local function ipEquals(ip1, ip2)
		return ip1[dataKey].rawIP == ip2[dataKey].rawIP
	end

	local function ipLessThan(ip1, ip2)
		return ip1[dataKey].rawIP < ip2[dataKey].rawIP
	end

	local function concatIPs(ip1, ip2)
		return ip1:getIP() .. ip2:getIP()
	end

	local function ipToString(ip)
		return ip:getIP()
	end

	-- Constructors
	makeIPAddress = function (rawIP)
		-- Constructs a new IPAddress object from a rawIP object. This function
		-- is for internal use; it is called by IPAddress.new and from other
		-- IPAddress methods, and should be available to the Subnet class, but
		-- should not be available to other modules.
		assert(type(rawIP) == 'table', 'rawIP was type ' .. type(rawIP) .. '; expected type table')

		-- Set up structure
		local obj = {}
		local data = {}
		data.rawIP = rawIP

		-- Public methods
		function obj:getIP()
			return tostring(data.rawIP)
		end

		function obj:getVersion()
			return data.rawIP:getVersion()
		end

		function obj:isIPv4()
			return data.rawIP:isIPv4()
		end

		function obj:isIPv6()
			return data.rawIP:isIPv6()
		end

		function obj:isInSubnet(subnet)
			return subnet:containsIP(self)
		end

		function obj:getNextIP()
			return makeIPAddress(data.rawIP:getAdjacent())
		end

		function obj:getPreviousIP()
			return makeIPAddress(data.rawIP:getAdjacent(true))
		end

		-- Metamethods
		return setmetatable(obj, {
			__eq = ipEquals,
			__lt = ipLessThan,
			__concat = concatIPs,
			__tostring = ipToString,
			__index = function (self, key)
				if key == dataKey then
					return data
				end
			end,
		})
	end

	function IPAddress.new(ip)
		checkType('IPAddress.new', 1, ip, 'string')
		local rawIP = RawIP.newFromIP(ip)
		if not rawIP then
			error(string.format("'%s' is an invalid IP", ip), 2)
		end
		return makeIPAddress(rawIP)
	end
end

--------------------------------------------------------------------------------
-- Subnet class
-- Represents a block of IPv4 or IPv6 addresses.
--------------------------------------------------------------------------------

do
	-- Initialize metatable
	local mt = {}

	-- Constructors
	makeSubnet = function (rawIP, bitLength)
		-- Set up structure
		local obj = setmetatable({}, mt)
		local data = {
			rawIP = rawIP,
			bitLength = bitLength,
		}

		-- Public methods
		function obj:getPrefix()
			if not data.prefix then
				data.prefix = makeIPAddress(
					data.rawIP:getPrefix(data.bitLength)
				)
			end
			return data.prefix
		end

		function obj:getHighestIP()
			if not data.highestIP then
				data.highestIP = makeIPAddress(
					data.rawIP:getHighestHost(data.bitLength)
				)
			end
			return data.highestIP
		end

		function obj:getBitLength()
			return data.bitLength
		end

		function obj:getCIDR()
			return string.format(
				'%s/%d',
				tostring(self:getPrefix()), self:getBitLength()
			)
		end

		function obj:getVersion()
			return data.rawIP:getVersion()
		end

		function obj:isIPv4()
			return data.rawIP:isIPv4()
		end

		function obj:isIPv6()
			return data.rawIP:isIPv6()
		end

		function obj:containsIP(ip)
			if self:getVersion() == ip:getVersion() then
				return self:getPrefix() <= ip and ip <= self:getHighestIP()
			end
			return false
		end

		function obj:overlapsSubnet(subnet)
			if self:getVersion() == subnet:getVersion() then
				return (
					subnet:getHighestIP() >= self:getPrefix() and
					subnet:getPrefix() <= self:getHighestIP()
				)
			end
			return false
		end

		return obj
	end

	function Subnet.new(cidr)
		checkType('Subnet.new', 1, cidr, 'string')
		local lhs, rhs = cidr:match('^%s*(.-)/(%d+)%s*$')
		if lhs then
			local bits = lhs:find(':', 1, true) and 128 or 32
			local n = tonumber(rhs)
			if n and n <= bits then
				local base = RawIP.newFromIP(lhs)
				local prefix = base:getPrefix(n)
				if base == prefix then
					return makeSubnet(prefix, n)
				end
			end
		end
		error(string.format("'%s' is an invalid CIDR string", cidr), 2)
	end

	-- Metamethods
	function mt:__eq(obj)
		return self:getCIDR() == obj:getCIDR()
	end

	function mt:__tostring()
		return self:getCIDR()
	end
end

return {
	IPAddress = IPAddress,
	Subnet = Subnet,
}
Retrieved from "https://crocwiki.com/wiki/Module:IP?oldid=30982"