twitst4tz

README.md (8309B)

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 # ipaddr.js — an IPv6 and IPv4 address manipulation library [![Build Status](https://travis-ci.org/whitequark/ipaddr.js.svg)](https://travis-ci.org/whitequark/ipaddr.js)
 
 ipaddr.js is a small (1.9K minified and gzipped) library for manipulating
 IP addresses in JavaScript environments. It runs on both CommonJS runtimes
 (e.g. [nodejs]) and in a web browser.
 
 ipaddr.js allows you to verify and parse string representation of an IP
 address, match it against a CIDR range or range list, determine if it falls
 into some reserved ranges (examples include loopback and private ranges),
 and convert between IPv4 and IPv4-mapped IPv6 addresses.
 
 [nodejs]: http://nodejs.org
 
 ## Installation
 
 `npm install ipaddr.js`
 
 or
 
 `bower install ipaddr.js`
 
 ## API
 
 ipaddr.js defines one object in the global scope: `ipaddr`. In CommonJS,
 it is exported from the module:
 
 ```js
 var ipaddr = require('ipaddr.js');
 ```
 
 The API consists of several global methods and two classes: ipaddr.IPv6 and ipaddr.IPv4.
 
 ### Global methods
 
 There are three global methods defined: `ipaddr.isValid`, `ipaddr.parse` and
 `ipaddr.process`. All of them receive a string as a single parameter.
 
 The `ipaddr.isValid` method returns `true` if the address is a valid IPv4 or
 IPv6 address, and `false` otherwise. It does not throw any exceptions.
 
 The `ipaddr.parse` method returns an object representing the IP address,
 or throws an `Error` if the passed string is not a valid representation of an
 IP address.
 
 The `ipaddr.process` method works just like the `ipaddr.parse` one, but it
 automatically converts IPv4-mapped IPv6 addresses to their IPv4 counterparts
 before returning. It is useful when you have a Node.js instance listening
 on an IPv6 socket, and the `net.ivp6.bindv6only` sysctl parameter (or its
 equivalent on non-Linux OS) is set to 0. In this case, you can accept IPv4
 connections on your IPv6-only socket, but the remote address will be mangled.
 Use `ipaddr.process` method to automatically demangle it.
 
 ### Object representation
 
 Parsing methods return an object which descends from `ipaddr.IPv6` or
 `ipaddr.IPv4`. These objects share some properties, but most of them differ.
 
 #### Shared properties
 
 One can determine the type of address by calling `addr.kind()`. It will return
 either `"ipv6"` or `"ipv4"`.
 
 An address can be converted back to its string representation with `addr.toString()`.
 Note that this method:
  * does not return the original string used to create the object (in fact, there is
    no way of getting that string)
  * returns a compact representation (when it is applicable)
 
 A `match(range, bits)` method can be used to check if the address falls into a
 certain CIDR range.
 Note that an address can be (obviously) matched only against an address of the same type.
 
 For example:
 
 ```js
 var addr = ipaddr.parse("2001:db8:1234::1");
 var range = ipaddr.parse("2001:db8::");
 
 addr.match(range, 32); // => true
 ```
 
 Alternatively, `match` can also be called as `match([range, bits])`. In this way,
 it can be used together with the `parseCIDR(string)` method, which parses an IP
 address together with a CIDR range.
 
 For example:
 
 ```js
 var addr = ipaddr.parse("2001:db8:1234::1");
 
 addr.match(ipaddr.parseCIDR("2001:db8::/32")); // => true
 ```
 
 A `range()` method returns one of predefined names for several special ranges defined
 by IP protocols. The exact names (and their respective CIDR ranges) can be looked up
 in the source: [IPv6 ranges] and [IPv4 ranges]. Some common ones include `"unicast"`
 (the default one) and `"reserved"`.
 
 You can match against your own range list by using
 `ipaddr.subnetMatch(address, rangeList, defaultName)` method. It can work with a mix of IPv6 or IPv4 addresses, and accepts a name-to-subnet map as the range list. For example:
 
 ```js
 var rangeList = {
   documentationOnly: [ ipaddr.parse('2001:db8::'), 32 ],
   tunnelProviders: [
     [ ipaddr.parse('2001:470::'), 32 ], // he.net
     [ ipaddr.parse('2001:5c0::'), 32 ]  // freenet6
   ]
 };
 ipaddr.subnetMatch(ipaddr.parse('2001:470:8:66::1'), rangeList, 'unknown'); // => "tunnelProviders"
 ```
 
 The addresses can be converted to their byte representation with `toByteArray()`.
 (Actually, JavaScript mostly does not know about byte buffers. They are emulated with
 arrays of numbers, each in range of 0..255.)
 
 ```js
 var bytes = ipaddr.parse('2a00:1450:8007::68').toByteArray(); // ipv6.google.com
 bytes // => [42, 0x00, 0x14, 0x50, 0x80, 0x07, 0x00, <zeroes...>, 0x00, 0x68 ]
 ```
 
 The `ipaddr.IPv4` and `ipaddr.IPv6` objects have some methods defined, too. All of them
 have the same interface for both protocols, and are similar to global methods.
 
 `ipaddr.IPvX.isValid(string)` can be used to check if the string is a valid address
 for particular protocol, and `ipaddr.IPvX.parse(string)` is the error-throwing parser.
 
 `ipaddr.IPvX.isValid(string)` uses the same format for parsing as the POSIX `inet_ntoa` function, which accepts unusual formats like `0xc0.168.1.1` or `0x10000000`. The function `ipaddr.IPv4.isValidFourPartDecimal(string)` validates the IPv4 address and also ensures that it is written in four-part decimal format.
 
 [IPv6 ranges]: https://github.com/whitequark/ipaddr.js/blob/master/src/ipaddr.coffee#L186
 [IPv4 ranges]: https://github.com/whitequark/ipaddr.js/blob/master/src/ipaddr.coffee#L71
 
 #### IPv6 properties
 
 Sometimes you will want to convert IPv6 not to a compact string representation (with
 the `::` substitution); the `toNormalizedString()` method will return an address where
 all zeroes are explicit.
 
 For example:
 
 ```js
 var addr = ipaddr.parse("2001:0db8::0001");
 addr.toString(); // => "2001:db8::1"
 addr.toNormalizedString(); // => "2001:db8:0:0:0:0:0:1"
 ```
 
 The `isIPv4MappedAddress()` method will return `true` if this address is an IPv4-mapped
 one, and `toIPv4Address()` will return an IPv4 object address.
 
 To access the underlying binary representation of the address, use `addr.parts`.
 
 ```js
 var addr = ipaddr.parse("2001:db8:10::1234:DEAD");
 addr.parts // => [0x2001, 0xdb8, 0x10, 0, 0, 0, 0x1234, 0xdead]
 ```
 
 A IPv6 zone index can be accessed via `addr.zoneId`:
 
 ```js
 var addr = ipaddr.parse("2001:db8::%eth0");
 addr.zoneId // => 'eth0'
 ```
 
 #### IPv4 properties
 
 `toIPv4MappedAddress()` will return a corresponding IPv4-mapped IPv6 address.
 
 To access the underlying representation of the address, use `addr.octets`.
 
 ```js
 var addr = ipaddr.parse("192.168.1.1");
 addr.octets // => [192, 168, 1, 1]
 ```
 
 `prefixLengthFromSubnetMask()` will return a CIDR prefix length for a valid IPv4 netmask or
 null if the netmask is not valid.
 
 ```js
 ipaddr.IPv4.parse('255.255.255.240').prefixLengthFromSubnetMask() == 28
 ipaddr.IPv4.parse('255.192.164.0').prefixLengthFromSubnetMask()  == null
 ```
 
 `subnetMaskFromPrefixLength()` will return an IPv4 netmask for a valid CIDR prefix length.
 
 ```js
 ipaddr.IPv4.subnetMaskFromPrefixLength(24) == "255.255.255.0"
 ipaddr.IPv4.subnetMaskFromPrefixLength(29) == "255.255.255.248"
 ```
 
 `broadcastAddressFromCIDR()` will return the broadcast address for a given IPv4 interface and netmask in CIDR notation.
 ```js
 ipaddr.IPv4.broadcastAddressFromCIDR("172.0.0.1/24") == "172.0.0.255"
 ```
 `networkAddressFromCIDR()` will return the network address for a given IPv4 interface and netmask in CIDR notation.
 ```js
 ipaddr.IPv4.networkAddressFromCIDR("172.0.0.1/24") == "172.0.0.0"
 ```
 
 #### Conversion
 
 IPv4 and IPv6 can be converted bidirectionally to and from network byte order (MSB) byte arrays.
 
 The `fromByteArray()` method will take an array and create an appropriate IPv4 or IPv6 object
 if the input satisfies the requirements. For IPv4 it has to be an array of four 8-bit values,
 while for IPv6 it has to be an array of sixteen 8-bit values.
 
 For example:
 ```js
 var addr = ipaddr.fromByteArray([0x7f, 0, 0, 1]);
 addr.toString(); // => "127.0.0.1"
 ```
 
 or
 
 ```js
 var addr = ipaddr.fromByteArray([0x20, 1, 0xd, 0xb8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1])
 addr.toString(); // => "2001:db8::1"
 ```
 
 Both objects also offer a `toByteArray()` method, which returns an array in network byte order (MSB).
 
 For example:
 ```js
 var addr = ipaddr.parse("127.0.0.1");
 addr.toByteArray(); // => [0x7f, 0, 0, 1]
 ```
 
 or
 
 ```js
 var addr = ipaddr.parse("2001:db8::1");
 addr.toByteArray(); // => [0x20, 1, 0xd, 0xb8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1]
 ```