Checks if a subnet contains a specific IP address. - Java Network

Java examples for Network:IP Address

  1. HOME
  2. Java
  3. Network
  4. IP Address

Description

Checks if a subnet contains a specific IP address.

Demo Code

/**/*  ww w. j a  v a 2s  .  c  om*/
 * Copyright 2009-2011 ?cole de technologie sup?rieure,
 * Communication Research Centre Canada,
 * Inocybe Technologies Inc. and 6837247 CANADA Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
//package com.java2s;
import java.net.InetAddress;

public class Main {
    /**
     * Checks if a subnet contains a specific IP address.
     * @param network The network address.
     * @param netmask The subnet mask.
     * @param ip The IP address to check.
     * @return A boolean value.
     */
    public static boolean contains(InetAddress network,
            InetAddress netmask, InetAddress ip) {

        byte[] networkBytes = network.getAddress();
        byte[] netmaskBytes = netmask.getAddress();
        byte[] ipBytes = ip.getAddress();

        /* check IPv4/v6-compatibility or parameters: */
        if (networkBytes.length != netmaskBytes.length
                || netmaskBytes.length != ipBytes.length) {
            return false;
        }

        /* Check if the masked network and ip addresses match: */
        for (int i = 0; i < netmaskBytes.length; i++) {
            int mask = netmaskBytes[i] & 0xff;
            if ((networkBytes[i] & mask) != (ipBytes[i] & mask)) {
                return false;
            }
        }
        return true;
    }
}

Related Tutorials