@dashevo/dashcore-lib/lib/util/ip.js

A pure and powerful JavaScript Dash library.

/* eslint-disable */
// TODO: Remove previous line and work through linting issues at next edit

var BufferWriter = require('../encoding/bufferwriter');
var BufferReader = require('../encoding/bufferreader');
var constants = require('../constants');
var serviceRegex =
  /^(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5]):[0-9]+$/;
var ipV6prefix = Buffer.from('00000000000000000000ffff', 'hex');
var emptyAddress = Buffer.alloc(18);
var EMPTY_FULL_IPV6_ADDRESS = '[0:0:0:0:0:0:0:0]:0';
var EMPTY_SHORT_IPV6_ADDRESS = '[::]:0';
var EMPTY_SHORT_ZERO_IPV6_ADDRESS = '[::0]:0';
var EMPTY_FULL_IPV4_ADDRESS = '0.0.0.0:0';
var EMPTY_SHORT_IPV4_ADDRESS = '0:0';
var EMPTY_ADDRESSES = [
  EMPTY_FULL_IPV6_ADDRESS,
  EMPTY_SHORT_IPV6_ADDRESS,
  EMPTY_SHORT_ZERO_IPV6_ADDRESS,
  EMPTY_FULL_IPV4_ADDRESS,
  EMPTY_SHORT_IPV4_ADDRESS,
];

/**
 * Maps ipv4:port to ipv6 buffer and port
 * Note: this is made mostly for the deterministic masternode list, which are ipv4 addresses encoded as ipv6 addresses
 * @param {string} string
 * @return {Buffer}
 */
function ipAndPortToBuffer(string) {
  if (isZeroAddress(string)) {
    return emptyAddress.slice();
  }
  if (!isIpV4(string)) {
    throw new Error('Only serialization of ipv4 and zero ipv6 is allowed');
  }
  var addressParts = string.split(':');
  var addressBytes = addressParts[0].split('.').map(function (byte) {
    return Number(byte);
  });
  var port = Number(addressParts[1]);

  var bufferWriter = new BufferWriter();
  bufferWriter.write(ipV6prefix);
  bufferWriter.write(Buffer.from(addressBytes));
  bufferWriter.writeUInt16BE(port);
  return bufferWriter.toBuffer();
}

/**
 * Parses ipv6 buffer and port to ipv4:port string
 * @param {Buffer} buffer
 * @return {string}
 */
function bufferToIPAndPort(buffer) {
  if (buffer.length !== 18) {
    throw new Error('Ip buffer has wrong size. Expected size is 18 bytes');
  }
  var bufferReader = new BufferReader(buffer);
  var ipV6Buffer = bufferReader.read(constants.IP_ADDRESS_SIZE);
  var port = bufferReader.readUInt16BE();

  // To get ipv4 bytes, we need to ignore first 12 bytes of ipv6
  var ipV4DecimalBytes = Array.prototype.slice.call(ipV6Buffer.slice(12, 16));
  var ipV4string = ipV4DecimalBytes.join('.');
  var serviceString = ipV4string + ':' + String(port);
  // This is a hack to match core implementation, which in case of an empty address returns ipv6 string
  serviceString = isZeroAddress(serviceString)
    ? EMPTY_FULL_IPV6_ADDRESS
    : serviceString;
  return serviceString;
}

/**
 * Checks if string is an ipv4 address
 * @param {string} ipAndPortString
 * @return {boolean}
 */
function isIpV4(ipAndPortString) {
  return serviceRegex.test(ipAndPortString);
}

/**
 * @param {string} address
 * @return {boolean}
 */
function isZeroAddress(address) {
  return EMPTY_ADDRESSES.includes(address);
}

var ip = {
  isIPV4: isIpV4,
  ipAndPortToBuffer: ipAndPortToBuffer,
  bufferToIPAndPort: bufferToIPAndPort,
  isZeroAddress: isZeroAddress,
  IP_AND_PORT_SIZE:
    constants.ipAddresses.IPV4MAPPEDHOST + constants.ipAddresses.PORT,
};

module.exports = ip;