| # ipaddr.js — an IPv6 and IPv4 address manipulation library [](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] |
| ``` |