Java InetAddress Create getNetworkInterfaceForRemoteIPAddress( InetAddress remoteAddress)

Description

get Network Interface For Remote IP Address

License

Open Source License

Declaration

public static NetworkInterface getNetworkInterfaceForRemoteIPAddress(
            InetAddress remoteAddress) throws SocketException 

Method Source Code

//package com.java2s;
/*/* w w w.j a v  a2  s  .  co  m*/
 * Copyright 2015 The OpenDCT Authors. All Rights Reserved
 *
 * 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.
 */

import java.net.*;

import java.util.Enumeration;

public class Main {
    public static NetworkInterface getNetworkInterfaceForRemoteIPAddress(
            InetAddress remoteAddress) throws SocketException {
        byte remoteAddressBytes[] = remoteAddress.getAddress();

        Enumeration<NetworkInterface> networkInterfaces = NetworkInterface
                .getNetworkInterfaces();

        while (networkInterfaces.hasMoreElements()) {
            NetworkInterface currentInterface = networkInterfaces
                    .nextElement();

            // Never try to match a loopback interface.
            if (currentInterface.isLoopback()) {
                continue;
            }

            for (InterfaceAddress address : currentInterface
                    .getInterfaceAddresses()) {
                byte localIPAddress[] = address.getAddress().getAddress();

                // Make sure these are the same kind of IP addresses. This should only differ if one of
                // the addresses is v4 and the other is v6.
                if (localIPAddress.length != remoteAddressBytes.length) {
                    continue;
                }

                byte localSubnet[] = new byte[localIPAddress.length];
                int localSubnetLength = address.getNetworkPrefixLength();

                boolean match = true;
                int bits = localSubnetLength;
                for (int i = 0; i < localSubnet.length; i++) {
                    if (bits < 8) {
                        localSubnet[i] = (byte) ~((1 << 8 - bits) - 1);

                        byte localAnd = (byte) (localIPAddress[i] & localSubnet[i]);
                        byte remoteAnd = (byte) (remoteAddressBytes[i] & localSubnet[i]);

                        if (localAnd != remoteAnd) {
                            match = false;
                            break;
                        }
                    } else if (!(localIPAddress[i] == remoteAddressBytes[i])) {
                        match = false;
                        break;
                    }

                    bits -= 8;
                }

                if (!match) {
                    continue;
                }

                return currentInterface;
            }
        }

        return null;
    }
}

Related

1. getNatType(final InetAddress localAdr, final InetAddress publicAdr)
2. getNetwork(InetAddress start, InetAddress end)
3. getNetworkCIDR(InetAddress addr, short prefixLength)
4. getNetworkInterface(InetAddress localAddress)
5. getNetworkInterfaceByIp(InetAddress inetAddress)
6. getNextAliablePort(InetAddress address, int startport)
7. getNextAvailablePort(InetAddress address, int port)
8. getOneDotPrefix(InetAddress addr)
9. getPing(InetAddress address, long timeout)