test/java/net/NetworkInterface/UniqueMacAddressesTest.java

/*
 * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 */

import java.net.InetAddress;
import java.net.NetworkInterface;
import java.net.SocketException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Enumeration;
import java.util.List;


/*
 * @test
 * @bug 8021372
 * @summary Tests that the MAC addresses returned by NetworkInterface.getNetworkInterfaces are unique for each adapter.
 *
 */
public class UniqueMacAddressesTest {

    public static void main(String[] args) throws Exception {
        new UniqueMacAddressesTest().execute();
        System.out.println("UniqueMacAddressesTest: OK");
    }

    public UniqueMacAddressesTest() {
        System.out.println("UniqueMacAddressesTest: start ");
    }

    public void execute() throws Exception {
        Enumeration<NetworkInterface> networkInterfaces;
        boolean areMacAddressesUnique = false;
        List<NetworkInterface> networkInterfaceList = new ArrayList<NetworkInterface>();
            networkInterfaces = NetworkInterface.getNetworkInterfaces();

        // build a list of NetworkInterface objects to test MAC address
        // uniqueness
        createNetworkInterfaceList(networkInterfaces, networkInterfaceList);
        areMacAddressesUnique = checkMacAddressesAreUnique(networkInterfaceList);
        if (!areMacAddressesUnique) {
            throw new RuntimeException("mac address uniqueness test failed");
        }
    }

    private boolean checkMacAddressesAreUnique (
            List<NetworkInterface> networkInterfaces) throws Exception {
        boolean uniqueMacAddresses = true;
        for (NetworkInterface networkInterface : networkInterfaces) {
            for (NetworkInterface comparisonNetIf : networkInterfaces) {
                System.out.println("Comparing netif "
                        + networkInterface.getName() + " and netif "
                        + comparisonNetIf.getName());
                if (testMacAddressesEqual(networkInterface, comparisonNetIf)) {
                    uniqueMacAddresses = false;
                    break;
                }
            }
            if (uniqueMacAddresses != true)
                break;
        }
        return uniqueMacAddresses;
    }

    private boolean testMacAddressesEqual(NetworkInterface netIf1,
            NetworkInterface netIf2) throws Exception {

        byte[] rawMacAddress1 = null;
        byte[] rawMacAddress2 = null;
        boolean macAddressesEqual = false;
        if (!netIf1.getName().equals(netIf2.getName())) {
            System.out.println("compare hardware addresses "
                +  createMacAddressString(netIf1) + " and " + createMacAddressString(netIf2));
            rawMacAddress1 = netIf1.getHardwareAddress();
            rawMacAddress2 = netIf2.getHardwareAddress();
            macAddressesEqual = Arrays.equals(rawMacAddress1, rawMacAddress2);
        } else {
            // same interface
            macAddressesEqual = false;
        }
        return macAddressesEqual;
    }

    private String createMacAddressString (NetworkInterface netIf) throws Exception {
        byte[] macAddr = netIf.getHardwareAddress();
        StringBuilder sb =  new StringBuilder();
        if (macAddr != null) {
            for (int i = 0; i < macAddr.length; i++) {
                sb.append(String.format("%02X%s", macAddr[i],
                        (i < macAddr.length - 1) ? "-" : ""));
            }
        }
        return sb.toString();
    }

    private void createNetworkInterfaceList(Enumeration<NetworkInterface> nis,
            List<NetworkInterface> networkInterfaceList) throws Exception {
        byte[] macAddr = null;
        NetworkInterface netIf = null;
        while (nis.hasMoreElements()) {
            netIf = (NetworkInterface) nis.nextElement();
            if (netIf.isUp()) {
                macAddr = netIf.getHardwareAddress();
                if (macAddr != null) {
                    System.out.println("Adding NetworkInterface "
                            + netIf.getName() + " with mac address "
                            + createMacAddressString(netIf));
                    networkInterfaceList.add(netIf);
                }
            }
        }
    }
}