package com.jacamars.dsp.rtb.blocks; import java.math.BigInteger; import java.net.InetAddress; import java.net.UnknownHostException; import java.nio.ByteBuffer; import java.util.ArrayList; import java.util.List; /** * A class that enables to get an IP range from CIDR specification. It supports * both IPv4 and IPv6. */ public class CIDRUtils { private final String cidr; private InetAddress inetAddress; private InetAddress startAddress; private InetAddress endAddress; private final int prefixLength; public CIDRUtils(String cidr) throws UnknownHostException { this.cidr = cidr; /* split CIDR to address and prefix part */ if (this.cidr.contains("/")) { int index = this.cidr.indexOf("/"); String addressPart = this.cidr.substring(0, index); String networkPart = this.cidr.substring(index + 1); inetAddress = InetAddress.getByName(addressPart); prefixLength = Integer.parseInt(networkPart); calculate(); } else { throw new IllegalArgumentException("not an valid CIDR format!"); } } public long getStartAddress() { ByteBuffer buffer = ByteBuffer.allocate(Long.SIZE); buffer.put(startAddress.getAddress()); buffer.position(0); Long longValue = buffer.getLong(); return longValue; } public long getEndAddress() { ByteBuffer buffer = ByteBuffer.allocate(Long.SIZE); buffer.put(endAddress.getAddress()); buffer.position(0); Long longValue = buffer.getLong(); return longValue; } private void calculate() throws UnknownHostException { ByteBuffer maskBuffer; int targetSize; if (inetAddress.getAddress().length == 4) { maskBuffer = ByteBuffer .allocate(4) .putInt(-1); targetSize = 4; } else { maskBuffer = ByteBuffer.allocate(16) .putLong(-1L) .putLong(-1L); targetSize = 16; } BigInteger mask = (new BigInteger(1, maskBuffer.array())).not().shiftRight(prefixLength); ByteBuffer buffer = ByteBuffer.wrap(inetAddress.getAddress()); BigInteger ipVal = new BigInteger(1, buffer.array()); BigInteger startIp = ipVal.and(mask); BigInteger endIp = startIp.add(mask.not()); byte[] startIpArr = toBytes(startIp.toByteArray(), targetSize); byte[] endIpArr = toBytes(endIp.toByteArray(), targetSize); this.startAddress = InetAddress.getByAddress(startIpArr); this.endAddress = InetAddress.getByAddress(endIpArr); } private byte[] toBytes(byte[] array, int targetSize) { int counter = 0; List<Byte> newArr = new ArrayList<Byte>(); while (counter < targetSize && (array.length - 1 - counter >= 0)) { newArr.add(0, array[array.length - 1 - counter]); counter++; } int size = newArr.size(); for (int i = 0; i < (targetSize - size); i++) { newArr.add(0, (byte) 0); } byte[] ret = new byte[newArr.size()]; for (int i = 0; i < newArr.size(); i++) { ret[i] = newArr.get(i); } return ret; } public String getNetworkAddress() { return this.startAddress.getHostAddress(); } public String getBroadcastAddress() { return this.endAddress.getHostAddress(); } public boolean isInRange(String ipAddress) throws UnknownHostException { InetAddress address = InetAddress.getByName(ipAddress); BigInteger start = new BigInteger(1, this.startAddress.getAddress()); BigInteger end = new BigInteger(1, this.endAddress.getAddress()); BigInteger target = new BigInteger(1, address.getAddress()); int st = start.compareTo(target); int te = target.compareTo(end); return (st == -1 || st == 0) && (te == -1 || te == 0); } }