README.md
1 # ipaddr.js — an IPv6 and IPv4 address manipulation library [](https://travis-ci.org/whitequark/ipaddr.js) 2 3 ipaddr.js is a small (1.9K minified and gzipped) library for manipulating 4 IP addresses in JavaScript environments. It runs on both CommonJS runtimes 5 (e.g. [nodejs]) and in a web browser. 6 7 ipaddr.js allows you to verify and parse string representation of an IP 8 address, match it against a CIDR range or range list, determine if it falls 9 into some reserved ranges (examples include loopback and private ranges), 10 and convert between IPv4 and IPv4-mapped IPv6 addresses. 11 12 [nodejs]: http://nodejs.org 13 14 ## Installation 15 16 `npm install ipaddr.js` 17 18 or 19 20 `bower install ipaddr.js` 21 22 ## API 23 24 ipaddr.js defines one object in the global scope: `ipaddr`. In CommonJS, 25 it is exported from the module: 26 27 ```js 28 var ipaddr = require('ipaddr.js'); 29 ``` 30 31 The API consists of several global methods and two classes: ipaddr.IPv6 and ipaddr.IPv4. 32 33 ### Global methods 34 35 There are three global methods defined: `ipaddr.isValid`, `ipaddr.parse` and 36 `ipaddr.process`. All of them receive a string as a single parameter. 37 38 The `ipaddr.isValid` method returns `true` if the address is a valid IPv4 or 39 IPv6 address, and `false` otherwise. It does not throw any exceptions. 40 41 The `ipaddr.parse` method returns an object representing the IP address, 42 or throws an `Error` if the passed string is not a valid representation of an 43 IP address. 44 45 The `ipaddr.process` method works just like the `ipaddr.parse` one, but it 46 automatically converts IPv4-mapped IPv6 addresses to their IPv4 counterparts 47 before returning. It is useful when you have a Node.js instance listening 48 on an IPv6 socket, and the `net.ivp6.bindv6only` sysctl parameter (or its 49 equivalent on non-Linux OS) is set to 0. In this case, you can accept IPv4 50 connections on your IPv6-only socket, but the remote address will be mangled. 51 Use `ipaddr.process` method to automatically demangle it. 52 53 ### Object representation 54 55 Parsing methods return an object which descends from `ipaddr.IPv6` or 56 `ipaddr.IPv4`. These objects share some properties, but most of them differ. 57 58 #### Shared properties 59 60 One can determine the type of address by calling `addr.kind()`. It will return 61 either `"ipv6"` or `"ipv4"`. 62 63 An address can be converted back to its string representation with `addr.toString()`. 64 Note that this method: 65 * does not return the original string used to create the object (in fact, there is 66 no way of getting that string) 67 * returns a compact representation (when it is applicable) 68 69 A `match(range, bits)` method can be used to check if the address falls into a 70 certain CIDR range. 71 Note that an address can be (obviously) matched only against an address of the same type. 72 73 For example: 74 75 ```js 76 var addr = ipaddr.parse("2001:db8:1234::1"); 77 var range = ipaddr.parse("2001:db8::"); 78 79 addr.match(range, 32); // => true 80 ``` 81 82 Alternatively, `match` can also be called as `match([range, bits])`. In this way, 83 it can be used together with the `parseCIDR(string)` method, which parses an IP 84 address together with a CIDR range. 85 86 For example: 87 88 ```js 89 var addr = ipaddr.parse("2001:db8:1234::1"); 90 91 addr.match(ipaddr.parseCIDR("2001:db8::/32")); // => true 92 ``` 93 94 A `range()` method returns one of predefined names for several special ranges defined 95 by IP protocols. The exact names (and their respective CIDR ranges) can be looked up 96 in the source: [IPv6 ranges] and [IPv4 ranges]. Some common ones include `"unicast"` 97 (the default one) and `"reserved"`. 98 99 You can match against your own range list by using 100 `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: 101 102 ```js 103 var rangeList = { 104 documentationOnly: [ ipaddr.parse('2001:db8::'), 32 ], 105 tunnelProviders: [ 106 [ ipaddr.parse('2001:470::'), 32 ], // he.net 107 [ ipaddr.parse('2001:5c0::'), 32 ] // freenet6 108 ] 109 }; 110 ipaddr.subnetMatch(ipaddr.parse('2001:470:8:66::1'), rangeList, 'unknown'); // => "tunnelProviders" 111 ``` 112 113 The addresses can be converted to their byte representation with `toByteArray()`. 114 (Actually, JavaScript mostly does not know about byte buffers. They are emulated with 115 arrays of numbers, each in range of 0..255.) 116 117 ```js 118 var bytes = ipaddr.parse('2a00:1450:8007::68').toByteArray(); // ipv6.google.com 119 bytes // => [42, 0x00, 0x14, 0x50, 0x80, 0x07, 0x00, <zeroes...>, 0x00, 0x68 ] 120 ``` 121 122 The `ipaddr.IPv4` and `ipaddr.IPv6` objects have some methods defined, too. All of them 123 have the same interface for both protocols, and are similar to global methods. 124 125 `ipaddr.IPvX.isValid(string)` can be used to check if the string is a valid address 126 for particular protocol, and `ipaddr.IPvX.parse(string)` is the error-throwing parser. 127 128 `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. 129 130 [IPv6 ranges]: https://github.com/whitequark/ipaddr.js/blob/master/src/ipaddr.coffee#L186 131 [IPv4 ranges]: https://github.com/whitequark/ipaddr.js/blob/master/src/ipaddr.coffee#L71 132 133 #### IPv6 properties 134 135 Sometimes you will want to convert IPv6 not to a compact string representation (with 136 the `::` substitution); the `toNormalizedString()` method will return an address where 137 all zeroes are explicit. 138 139 For example: 140 141 ```js 142 var addr = ipaddr.parse("2001:0db8::0001"); 143 addr.toString(); // => "2001:db8::1" 144 addr.toNormalizedString(); // => "2001:db8:0:0:0:0:0:1" 145 ``` 146 147 The `isIPv4MappedAddress()` method will return `true` if this address is an IPv4-mapped 148 one, and `toIPv4Address()` will return an IPv4 object address. 149 150 To access the underlying binary representation of the address, use `addr.parts`. 151 152 ```js 153 var addr = ipaddr.parse("2001:db8:10::1234:DEAD"); 154 addr.parts // => [0x2001, 0xdb8, 0x10, 0, 0, 0, 0x1234, 0xdead] 155 ``` 156 157 A IPv6 zone index can be accessed via `addr.zoneId`: 158 159 ```js 160 var addr = ipaddr.parse("2001:db8::%eth0"); 161 addr.zoneId // => 'eth0' 162 ``` 163 164 #### IPv4 properties 165 166 `toIPv4MappedAddress()` will return a corresponding IPv4-mapped IPv6 address. 167 168 To access the underlying representation of the address, use `addr.octets`. 169 170 ```js 171 var addr = ipaddr.parse("192.168.1.1"); 172 addr.octets // => [192, 168, 1, 1] 173 ``` 174 175 `prefixLengthFromSubnetMask()` will return a CIDR prefix length for a valid IPv4 netmask or 176 null if the netmask is not valid. 177 178 ```js 179 ipaddr.IPv4.parse('255.255.255.240').prefixLengthFromSubnetMask() == 28 180 ipaddr.IPv4.parse('255.192.164.0').prefixLengthFromSubnetMask() == null 181 ``` 182 183 `subnetMaskFromPrefixLength()` will return an IPv4 netmask for a valid CIDR prefix length. 184 185 ```js 186 ipaddr.IPv4.subnetMaskFromPrefixLength(24) == "255.255.255.0" 187 ipaddr.IPv4.subnetMaskFromPrefixLength(29) == "255.255.255.248" 188 ``` 189 190 `broadcastAddressFromCIDR()` will return the broadcast address for a given IPv4 interface and netmask in CIDR notation. 191 ```js 192 ipaddr.IPv4.broadcastAddressFromCIDR("172.0.0.1/24") == "172.0.0.255" 193 ``` 194 `networkAddressFromCIDR()` will return the network address for a given IPv4 interface and netmask in CIDR notation. 195 ```js 196 ipaddr.IPv4.networkAddressFromCIDR("172.0.0.1/24") == "172.0.0.0" 197 ``` 198 199 #### Conversion 200 201 IPv4 and IPv6 can be converted bidirectionally to and from network byte order (MSB) byte arrays. 202 203 The `fromByteArray()` method will take an array and create an appropriate IPv4 or IPv6 object 204 if the input satisfies the requirements. For IPv4 it has to be an array of four 8-bit values, 205 while for IPv6 it has to be an array of sixteen 8-bit values. 206 207 For example: 208 ```js 209 var addr = ipaddr.fromByteArray([0x7f, 0, 0, 1]); 210 addr.toString(); // => "127.0.0.1" 211 ``` 212 213 or 214 215 ```js 216 var addr = ipaddr.fromByteArray([0x20, 1, 0xd, 0xb8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1]) 217 addr.toString(); // => "2001:db8::1" 218 ``` 219 220 Both objects also offer a `toByteArray()` method, which returns an array in network byte order (MSB). 221 222 For example: 223 ```js 224 var addr = ipaddr.parse("127.0.0.1"); 225 addr.toByteArray(); // => [0x7f, 0, 0, 1] 226 ``` 227 228 or 229 230 ```js 231 var addr = ipaddr.parse("2001:db8::1"); 232 addr.toByteArray(); // => [0x20, 1, 0xd, 0xb8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1] 233 ```