/*

 * 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.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * 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.

 */

/*

 *

 *  (C) Copyright IBM Corp. 1999 All Rights Reserved.

 *  Copyright 1997 The Open Group Research Institute.  All rights reserved.

 */

package sun.security.krb5.internal;

import sun.security.krb5.Config;

import sun.security.krb5.KrbException;

import sun.security.krb5.Asn1Exception;

import sun.security.krb5.internal.util.KerberosFlags;

import sun.security.util.*;

import java.io.IOException;

/**

 * Implements the ASN.1 KDCOptions type.

 *

 * <pre>{@code

 * KDCOptions   ::= KerberosFlags

 *      -- reserved(0),

 *      -- forwardable(1),

 *      -- forwarded(2),

 *      -- proxiable(3),

 *      -- proxy(4),

 *      -- allow-postdate(5),

 *      -- postdated(6),

 *      -- unused7(7),

 *      -- renewable(8),

 *      -- unused9(9),

 *      -- unused10(10),

 *      -- opt-hardware-auth(11),

 *      -- unused12(12),

 *      -- unused13(13),

 * -- 15 is reserved for canonicalize

 *      -- unused15(15),

 * -- 26 was unused in 1510

 *      -- disable-transited-check(26),

 *      -- renewable-ok(27),

 *      -- enc-tkt-in-skey(28),

 *      -- renew(30),

 *      -- validate(31)

 *

 * KerberosFlags   ::= BIT STRING (SIZE (32..MAX))

 *                      -- minimum number of bits shall be sent,

 *                      -- but no fewer than 32

 *

 * }</pre>

 *

 * <p>

 * This definition reflects the Network Working Group RFC 4120

 * specification available at

 * <a href="http://www.ietf.org/rfc/rfc4120.txt">

 * http://www.ietf.org/rfc/rfc4120.txt</a>.

 *

 * <p>

 * This class appears as data field in the initial request(KRB_AS_REQ)

 * or subsequent request(KRB_TGS_REQ) to the KDC and indicates the flags

 * that the client wants to set on the tickets.

 *

 * The optional bits are:

 * <UL>

 *  <LI>KDCOptions.RESERVED

 *  <LI>KDCOptions.FORWARDABLE

 *  <LI>KDCOptions.FORWARDED

 *  <LI>KDCOptions.PROXIABLE

 *  <LI>KDCOptions.PROXY

 *  <LI>KDCOptions.ALLOW_POSTDATE

 *  <LI>KDCOptions.POSTDATED

 *  <LI>KDCOptions.RENEWABLE

 *  <LI>KDCOptions.RENEWABLE_OK

 *  <LI>KDCOptions.ENC_TKT_IN_SKEY

 *  <LI>KDCOptions.RENEW

 *  <LI>KDCOptions.VALIDATE

 *  </UL>

 * <p> Various checks must be made before honoring an option. The restrictions

 * on the use of some options are as follows:

 * <ol>

 * <li> FORWARDABLE, FORWARDED, PROXIABLE, RENEWABLE options may be set in

 * subsequent request only if the ticket_granting ticket on which it is based has

 * the same options (FORWARDABLE, FORWARDED, PROXIABLE, RENEWABLE) set.

 * <li> ALLOW_POSTDATE may be set in subsequent request only if the

 * ticket-granting ticket on which it is based also has its MAY_POSTDATE flag set.

 * <li> POSTDATED may be set in subsequent request only if the

 * ticket-granting ticket on which it is based also has its MAY_POSTDATE flag set.

 * <li> RENEWABLE or RENEW may be set in subsequent request only if the

 * ticket-granting ticket on which it is based also has its RENEWABLE flag set.

 * <li> POXY may be set in subsequent request only if the ticket-granting ticket

 * on which it is based also has its PROXIABLE flag set, and the address(es) of

 * the host from which the resulting ticket is to be valid should be included

 * in the addresses field of the request.

 * <li>FORWARDED, PROXY, ENC_TKT_IN_SKEY, RENEW, VALIDATE are used only in

 * subsequent requests.

 * </ol>

 */

public class KDCOptions extends KerberosFlags {

    private static final int KDC_OPT_PROXIABLE = 0x10000000;

    private static final int KDC_OPT_RENEWABLE_OK = 0x00000010;

    private static final int KDC_OPT_FORWARDABLE = 0x40000000;

    // KDC Options

    public static final int RESERVED        = 0;

    public static final int FORWARDABLE     = 1;

    public static final int FORWARDED       = 2;

    public static final int PROXIABLE       = 3;

    public static final int PROXY           = 4;

    public static final int ALLOW_POSTDATE  = 5;

    public static final int POSTDATED       = 6;

    public static final int UNUSED7         = 7;

    public static final int RENEWABLE       = 8;

    public static final int UNUSED9         = 9;

    public static final int UNUSED10        = 10;

    public static final int UNUSED11        = 11;

    public static final int CNAME_IN_ADDL_TKT = 14;

    public static final int CANONICALIZE    = 15;

    public static final int RENEWABLE_OK    = 27;

    public static final int ENC_TKT_IN_SKEY = 28;

    public static final int RENEW           = 30;

    public static final int VALIDATE        = 31;

    private static final String[] names = {

        "RESERVED",         //0

        "FORWARDABLE",      //1;

        "FORWARDED",        //2;

        "PROXIABLE",        //3;

        "PROXY",            //4;

        "ALLOW_POSTDATE",   //5;

        "POSTDATED",        //6;

        "UNUSED7",          //7;

        "RENEWABLE",        //8;

        "UNUSED9",          //9;

        "UNUSED10",         //10;

        "UNUSED11",         //11;

        null,null,

        "CNAME_IN_ADDL_TKT",//14;

        "CANONICALIZE",     //15;

        null,null,null,null,null,null,null,null,null,null,null,

        "RENEWABLE_OK",     //27;

        "ENC_TKT_IN_SKEY",  //28;

        null,

        "RENEW",            //30;

        "VALIDATE",         //31;

    };

    private boolean DEBUG = Krb5.DEBUG;

    public static KDCOptions with(int... flags) {

        KDCOptions options = new KDCOptions();

        for (int flag: flags) {

            options.set(flag, true);

        }

        return options;

    }

    public KDCOptions() {

        super(Krb5.KDC_OPTS_MAX + 1);

        setDefault();

    }

    public KDCOptions(int size, byte[] data) throws Asn1Exception {

        super(size, data);

        if ((size > data.length * BITS_PER_UNIT) || (size > Krb5.KDC_OPTS_MAX + 1))

            throw new Asn1Exception(Krb5.BITSTRING_BAD_LENGTH);

    }

    /**

     * Constructs a KDCOptions from the specified bit settings.

     *

     * @param data the bits to be set for the KDCOptions.

     * @exception Asn1Exception if an error occurs while decoding an ASN1

     * encoded data.

     *

     */

    public KDCOptions(boolean[] data) throws Asn1Exception {

        super(data);

        if (data.length > Krb5.KDC_OPTS_MAX + 1) {

            throw new Asn1Exception(Krb5.BITSTRING_BAD_LENGTH);

        }

    }

    public KDCOptions(DerValue encoding) throws Asn1Exception, IOException {

        this(encoding.getUnalignedBitString(true).toBooleanArray());

    }

    /**

     * Constructs a KDCOptions from the passed bit settings.

     *

     * @param options the bits to be set for the KDCOptions.

     *

     */

    public KDCOptions(byte[] options) {

        super(options.length * BITS_PER_UNIT, options);

    }

    /**

     * Parse (unmarshal) a KDCOptions from a DER input stream.  This form

     * parsing might be used when expanding a value which is part of

     * a constructed sequence and uses explicitly tagged type.

     *

     * @param data the Der input stream value, which contains one or more

     * marshaled value.

     * @param explicitTag tag number.

     * @param optional indicate if this data field is optional

     * @return an instance of KDCOptions.

     * @exception Asn1Exception if an error occurs while decoding an ASN1 encoded data.

     * @exception IOException if an I/O error occurs while reading encoded data.

     *

     */

    public static KDCOptions parse(DerInputStream data, byte explicitTag, boolean optional) throws Asn1Exception, IOException {

        if ((optional) && (((byte)data.peekByte() & (byte)0x1F) != explicitTag))

            return null;

        DerValue der = data.getDerValue();

        if (explicitTag != (der.getTag() & (byte)0x1F))  {

            throw new Asn1Exception(Krb5.ASN1_BAD_ID);

        } else {

            DerValue subDer = der.getData().getDerValue();

            return new KDCOptions(subDer);

        }

    }

    /**

     * Sets the value(true/false) for one of the <code>KDCOptions</code>.

     *

     * @param option an option bit.

     * @param value true if the option is selected, false if the option is not selected.

     * @exception ArrayIndexOutOfBoundsException if array index out of bound occurs.

     * @see sun.security.krb5.internal.Krb5

     */

    public void set(int option, boolean value) throws ArrayIndexOutOfBoundsException {

        super.set(option, value);

    }

    /**

     * Gets the value(true/false) for one of the <code>KDCOptions</code>.

     *

     * @param option an option bit.

     * @return value true if the option is selected, false if the option is not selected.

     * @exception ArrayIndexOutOfBoundsException if array index out of bound occurs.

     * @see sun.security.krb5.internal.Krb5

     */

    public boolean get(int option) throws ArrayIndexOutOfBoundsException {

        return super.get(option);

    }

    @Override public String toString() {

        StringBuilder sb = new StringBuilder();

        sb.append("KDCOptions: ");

        for (int i=0; i<Krb5.KDC_OPTS_MAX+1; i++) {

            if (get(i)) {

                if (names[i] != null) {

                    sb.append(names[i]).append(",");

                } else {

                    sb.append(i).append(",");

                }

            }

        }

        return sb.toString();

    }

    private void setDefault() {

        try {

            Config config = Config.getInstance();

            // If key not present, returns Integer.MIN_VALUE, which is

            // almost all zero.

            int options = config.getIntValue("libdefaults",

                    "kdc_default_options");

            if ((options & KDC_OPT_RENEWABLE_OK) == KDC_OPT_RENEWABLE_OK) {

                set(RENEWABLE_OK, true);

            } else {

                if (config.getBooleanValue("libdefaults", "renewable")) {

                    set(RENEWABLE_OK, true);

                }

            }

            if ((options & KDC_OPT_PROXIABLE) == KDC_OPT_PROXIABLE) {

                set(PROXIABLE, true);

            } else {

                if (config.getBooleanValue("libdefaults", "proxiable")) {

                    set(PROXIABLE, true);

                }

            }

            if ((options & KDC_OPT_FORWARDABLE) == KDC_OPT_FORWARDABLE) {

                set(FORWARDABLE, true);

            } else {

                if (config.getBooleanValue("libdefaults", "forwardable")) {

                    set(FORWARDABLE, true);

                }

            }

        } catch (KrbException e) {

            if (DEBUG) {

                System.out.println("Exception in getting default values for " +

                        "KDC Options from the configuration ");

                e.printStackTrace();

            }

        }

    }

}