com.github.shoothzj.javatool.util.IpAddressMatcher Maven / Gradle / Ivy
package com.github.shoothzj.javatool.util;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.Arrays;
/**
* Matches a request based on IP Address or subnet mask matching against the remote
* address.
*
* Both IPv6 and IPv4 addresses are supported, but a matcher which is configured with an
* IPv4 address will never match a request which returns an IPv6 address, and vice-versa.
*
* @author Luke Taylor
* @since 3.0.2
*
* slightly modified by omidzk to have zero dependency to any frameworks other than the JDK.
*/
public final class IpAddressMatcher {
private final int nMaskBits;
private final InetAddress requiredAddress;
/**
* Takes a specific IP address or a range specified using the IP/Netmask (e.g.
* 192.168.1.0/24 or 202.24.0.0/14).
*
* @param ipAddress the address or range of addresses from which the request must
* come.
*/
public IpAddressMatcher(String ipAddress) {
if (ipAddress.indexOf('/') > 0) {
String[] addressAndMask = ipAddress.split("/");
ipAddress = addressAndMask[0];
nMaskBits = Integer.parseInt(addressAndMask[1]);
}
else {
nMaskBits = -1;
}
requiredAddress = parseAddress(ipAddress);
}
public boolean matches(String address) {
InetAddress remoteAddress = parseAddress(address);
if (!requiredAddress.getClass().equals(remoteAddress.getClass())) {
return false;
}
if (nMaskBits < 0) {
return remoteAddress.equals(requiredAddress);
}
byte[] remAddr = remoteAddress.getAddress();
byte[] reqAddr = requiredAddress.getAddress();
int oddBits = nMaskBits % 8;
int nMaskBytes = nMaskBits / 8 + (oddBits == 0 ? 0 : 1);
byte[] mask = new byte[nMaskBytes];
Arrays.fill(mask, 0, oddBits == 0 ? mask.length : mask.length - 1, (byte) 0xFF);
if (oddBits != 0) {
int finalByte = (1 << oddBits) - 1;
finalByte <<= 8 - oddBits;
mask[mask.length - 1] = (byte) finalByte;
}
// System.out.println("Mask is " + new sun.misc.HexDumpEncoder().encode(mask));
for (int i = 0; i < mask.length; i++) {
if ((remAddr[i] & mask[i]) != (reqAddr[i] & mask[i])) {
return false;
}
}
return true;
}
private InetAddress parseAddress(String address) {
try {
return InetAddress.getByName(address);
}
catch (UnknownHostException e) {
throw new IllegalArgumentException("Failed to parse address" + address, e);
}
}
}