IPv4 Network Info Calculator & Iterator

iterate_network.js

function getIPv4Range(networkString) {
  const networkdef = networkString.split('/');
  const netmask = parseInt(networkdef[1])
  const bitmask = 32 - netmask;
  const quads = networkdef[0].split('.');
  const addrbin =
    (parseInt(quads[0]) << 24) +
    (parseInt(quads[1]) << 16) +
    (parseInt(quads[2]) <<  8) +
    parseInt(quads[3]);
  const network = (addrbin >>> bitmask) << bitmask;
  const wildcard = 0xFFFFFFFF >>> netmask;
  const broadcast = network ^ wildcard;
  return [network + 1, broadcast - 1];
}

function binToQuads(addrbits) {
  const quadOne = addrbits >>> 24;
  const quadTwo = (addrbits & 0x00FF0000) >> 16;
  const quadThree = (addrbits & 0x0000FF00) >> 8;
  const quadFour = addrbits & 0x000000FF;
  return `${quadOne}.${quadTwo}.${quadThree}.${quadFour}`;
}

const [startAddr, endAddr] = getIPv4Range("127.0.0.1/29");
for(var addr = startAddr; addr <= endAddr; ++addr) {
  console.log(binToQuads(addr));
}

network_info.js

function getNetworkInfo(networkString) {
  const networkdef = networkString.split('/');
  const netmask = parseInt(networkdef[1])
  const bitmask = 32 - netmask;
  const quads = networkdef[0].split('.');
  const addrbin =
    (parseInt(quads[0]) << 24) +
    (parseInt(quads[1]) << 16) +
    (parseInt(quads[2]) <<  8) +
    parseInt(quads[3]);
  const network = (addrbin >>> bitmask) << bitmask;
  const wildcard = 0xFFFFFFFF >>> netmask;
  const broadcast = network ^ wildcard;

  return {
    network: `${binToQuads(network)}/${netmask}`,
    wildcard: binToQuads(wildcard),
    broadcast: binToQuads(broadcast),
    firstAddress: binToQuads(network + 1),
    lastAddress: binToQuads(broadcast - 1),
    addressCount: broadcast - network - 1
  };
}

function binToQuads(addrbits) {
  const quadOne = addrbits >>> 24;
  const quadTwo = (addrbits & 0x00FF0000) >> 16;
  const quadThree = (addrbits & 0x0000FF00) >> 8;
  const quadFour = addrbits & 0x000000FF;
  return `${quadOne}.${quadTwo}.${quadThree}.${quadFour}`;
}

console.log(getNetworkInfo("127.0.0.1/19"));