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cidr-tools

Tools to work with IPv4 and IPv6 CIDR

Usage

import {mergeCidr, excludeCidr, expandCidr, overlapCidr, containsCidr, normalizeCidr, parseCidr} from "cidr-tools";

mergeCidr(["1.0.0.0/24", "1.0.1.0/24"]);
//=> ["1.0.0.0/23"]

excludeCidr(["::1/127"], "::1/128");
//=> ["::/128"]

Array.from(expandCidr(["2001:db8::/126"]));
//=> ["2001:db8::", "2001:db8::1", "2001:db8::2", "2001:db8::3"]

overlapCidr("1.0.0.0/24", "1.0.0.128/25");
//=> true

containsCidr(["1.0.0.0/24", "2.0.0.0/24"], "1.0.0.1");
//=> true

normalizeCidr("::ffff/64");
//=> "::/64"

parseCidr("::/64");
// => {cidr: "::/64", version: 6, prefix: "64", start: 0n, end: 18446744073709551615n}

API

All functions take CIDR addresses or single IP addresses. On single addresses, a prefix of /32 or /128 is assumed. Function that return networks will return a merged and sorted set of networks with IPv4 sorted before IPv6.

It is expected that the passed CIDRs and IPs are validated as the module's own input validation is rudimentary. You are encouraged to use modules like is-cidr and is-ip to validate before passing to this module.

This module requires BigInt support in your environment.

mergeCidr(networks)

networks String or Array: One or more CIDR or IP addresses.

Returns an array of merged networks.

excludeCidr(baseNetworks, excludeNetworks)

baseNetworks String or Array: One or more CIDR or IP addresses.
excludeNetworks String or Array: One or more CIDR or IP addresses to exclude from baseNetworks.

Returns an array of merged remaining networks of the subtraction of excludeNetworks from baseNetworks.

expandCidr(networks)

networks String or Array: One or more CIDR or IP addresses.

Returns a generator for individual IPs contained in the networks.

Be aware that passing large networks that contain millions of IPs can result in memory exhaustion and slow execution time. It's recommended to validate the amount of IPs first, for example, like this:

import {parseCidr} from "cidr-tools";

const {start, end} = parseCidr("1.2.3.4/2");
if (end - start >= 1000000n) {
  throw new Error("Too many IPs");
}

overlapCidr(networksA, networksB)

networksA String or Array: One or more CIDR or IP address.
networksB String or Array: One or more CIDR or IP address.

Returns a boolean that indicates if networksA overlap (intersect) with networksB.

containsCidr(networksA, networksB)

networksA String or Array: One or more CIDR or IP address.
networksB String or Array: One or more CIDR or IP address.

Returns a boolean that indicates whether networksA fully contain all networksB.

normalizeCidr(networks, [opts])

networks String or Array: One or more CIDR or IP address.

Returns a string or array (depending on input) with a normalized representation. Will not include a prefix on single IPs. Will set network address to the start of the network.

opts: Object

compress: Whether to compress the IP. For IPv6, this means the "best representation" all-lowercase shortest possible form. Default: true.
hexify: Whether to convert IPv4-Mapped IPv6 addresses to hex. Default: false.

parseCidr(network)

network String: A CIDR or IP address.

Returns a parsed Object which is used internally by this module. It can be used to test whether the passed network is IPv4 or IPv6 or to work with the BigInts directly.

parsed: Object

cidr String: The CIDR of the network.
ip String: The IP address inside the CIDR, including any %scopeid if present.
version Number: IP protocol version. Either 4 or 6.
prefix String: The network prefix, e.g. 64.
prefixPresent Boolean: Whether the passed string has a network prefix.
start BigInt: Start number of the network.
end BigInt: End number of the network.

ip-bigint - Convert IPv4 and IPv6 addresses to native BigInt and vice-versa
ip-regex - Regular expression for matching IP addresses
is-cidr - Check if a string is an IP address in CIDR notation
is-ip - Check if a string is an IP address
cidr-regex - Check if a string is an IP address in CIDR notation