/*

 * Copyright (c) 2009, 2012, 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

import java.io.*;

import java.net.BindException;

import java.net.DatagramPacket;

import java.net.DatagramSocket;

import java.net.InetAddress;

import java.util.regex.Matcher;

import java.util.regex.Pattern;

import javax.security.auth.login.LoginException;

import sun.security.krb5.Asn1Exception;

import sun.security.krb5.Config;

public class BadKdc {

    // Matches the krb5 debug output:

    // >>> KDCCommunication: kdc=kdc.rabbit.hole UDP:14319, timeout=2000,...

    //                                               ^ kdc#         ^ timeout

    static final Pattern re = Pattern.compile(

            ">>> KDCCommunication: kdc=kdc.rabbit.hole UDP:(\\d)...., " +

            "timeout=(\\d+),");

    // Ratio for timeout values of all timeout tests. Not final so that

    // each test can choose their own.

    static float ratio = 2f;

    static void setRatio(float ratio) {

        BadKdc.ratio = ratio;

    }

    static float getRatio() {

        return ratio;

    }

    // Gets real timeout value. This method is called when writing krb5.conf

    static int toReal(int from) {

        return (int)(from * ratio + .5);

    }

    // De-ratio a millisecond value to second

    static int toSymbolicSec(int from) {

        return (int)(from / ratio / 1000f + 0.5);

    }

    /*

     * There are several cases this test fails:

     *

     * 1. The random selected port is used by another process. No good way to

     * prevent this happening, coz krb5.conf must be written before KDC starts.

     * There are two different outcomes:

     *

     *  a. Cannot start the KDC. A BindException thrown.

     *  b. When trying to access a non-existing KDC, a response is received!

     *     Most likely a Asn1Exception thrown

     *

     * 2. Even if a KDC is started, and more than 20 seconds pass by, a timeout

     * can still happens for the first UDP request. In fact, the KDC did not

     * received it at all. This happens on almost all platforms, especially

     * solaris-i586 and solaris-x64.

     *

     * To avoid them:

     *

     * 1. Catch those exceptions and ignore

     *

     * 2. a. Make the timeout longer? useless

     *    b. Read the output carefully, if there is a timeout, it's OK.

     *       Just make sure the retries times and KDCs are correct.

     *       This is tough.

     *    c. Feed the KDC a UDP packet first. The current "solution".

     */

    public static void go(String... expected)

            throws Exception {

        try {

            go0(expected);

        } catch (BindException be) {

            System.out.println("The random port is used by another process");

        } catch (LoginException le) {

            Throwable cause = le.getCause();

            if (cause instanceof Asn1Exception) {

                System.out.println("Bad packet possibly from another process");

                return;

            }

            throw le;

        }

    }

    public static void go0(String... expected)

            throws Exception {

        System.setProperty("sun.security.krb5.debug", "true");

        // Idle UDP sockets will trigger a SocketTimeoutException, without it,

        // a PortUnreachableException will be thrown.

        DatagramSocket d1 = null, d2 = null, d3 = null;

        // Make sure KDCs' ports starts with 1 and 2 and 3,

        // useful for checking debug output.

        int p1 = 10000 + new java.util.Random().nextInt(10000);

        int p2 = 20000 + new java.util.Random().nextInt(10000);

        int p3 = 30000 + new java.util.Random().nextInt(10000);

        FileWriter fw = new FileWriter("alternative-krb5.conf");

        fw.write("[libdefaults]\n" +

                "default_realm = " + OneKDC.REALM + "\n" +

                "kdc_timeout = " + toReal(2000) + "\n");

        fw.write("[realms]\n" + OneKDC.REALM + " = {\n" +

                "kdc = " + OneKDC.KDCHOST + ":" + p1 + "\n" +

                "kdc = " + OneKDC.KDCHOST + ":" + p2 + "\n" +

                "kdc = " + OneKDC.KDCHOST + ":" + p3 + "\n" +

                "}\n");

        fw.close();

        System.setProperty("java.security.krb5.conf", "alternative-krb5.conf");

        Config.refresh();

        // Turn on k3 only

        d1 = new DatagramSocket(p1);

        d2 = new DatagramSocket(p2);

        KDC k3 = on(p3);

        test(expected[0]);

        test(expected[1]);

        Config.refresh();

        test(expected[2]);

        k3.terminate(); // shutdown k3

        d3 = new DatagramSocket(p3);

        d2.close();

        on(p2);         // k2 is on

        test(expected[3]);

        d1.close();

        on(p1);         // k1 and k2 is on

        test(expected[4]);

        d3.close();

    }

    private static KDC on(int p) throws Exception {

        KDC k = new KDC(OneKDC.REALM, OneKDC.KDCHOST, p, true);

        k.addPrincipal(OneKDC.USER, OneKDC.PASS);

        k.addPrincipalRandKey("krbtgt/" + OneKDC.REALM);

        // Feed a packet to newly started KDC to warm it up

        System.err.println("-------- IGNORE THIS ERROR MESSAGE --------");

        new DatagramSocket().send(

                new DatagramPacket("Hello".getBytes(), 5,

                        InetAddress.getByName(OneKDC.KDCHOST), p));

        return k;

    }

    private static void test(String expected) throws Exception {

        ByteArrayOutputStream bo = new ByteArrayOutputStream();

        System.out.println("----------------- TEST -----------------");

        try {

            test0(bo, expected);

        } catch (Exception e) {

            System.out.println("----------------- ERROR -----------------");

            System.out.println(new String(bo.toByteArray()));

            System.out.println("--------------- ERROR END ---------------");

            throw e;

        }

    }

    /**

     * One round of test for max_retries and timeout.

     * @param expected the expected kdc# timeout kdc# timeout...

     */

    private static void test0(ByteArrayOutputStream bo, String expected)

            throws Exception {

        PrintStream oldout = System.out;

        boolean failed = false;

        System.setOut(new PrintStream(bo));

        try {

            Context.fromUserPass(OneKDC.USER, OneKDC.PASS, false);

        } catch (Exception e) {

            failed = true;

        } finally {

            System.setOut(oldout);

        }

        String[] lines = new String(bo.toByteArray()).split("\n");

        StringBuilder sb = new StringBuilder();

        for (String line: lines) {

            Matcher m = re.matcher(line);

            if (m.find()) {

                System.out.println(line);

                sb.append(m.group(1))

                        .append(toSymbolicSec(Integer.parseInt(m.group(2))));

            }

        }

        if (failed) sb.append('-');

        String output = sb.toString();

        System.out.println("Expected: " + expected + ", actual " + output);

        if (!output.matches(expected)) {

            throw new Exception("Does not match");

        }

    }

}