/*

 * Copyright 2005 Sun Microsystems, Inc.  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.  Sun designates this

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

 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package sun.net.www.protocol.http;

import java.io.IOException;

import org.ietf.jgss.GSSContext;

import org.ietf.jgss.GSSException;

import org.ietf.jgss.GSSName;

import org.ietf.jgss.Oid;

import sun.security.jgss.GSSManagerImpl;

import sun.security.jgss.GSSUtil;

/**

 * This class encapsulates all JAAS and JGSS API calls in a seperate class

 * outside NegotiateAuthentication.java so that J2SE build can go smoothly

 * without the presence of it.

 *

 * @author weijun.wang@sun.com

 * @since 1.6

 */

public class NegotiatorImpl extends Negotiator {

    private static final boolean DEBUG =

        java.security.AccessController.doPrivileged(

              new sun.security.action.GetBooleanAction("sun.security.krb5.debug"));

    private GSSContext context;

    private byte[] oneToken;

    /**

     * Initialize the object, which includes:<ul>

     * <li>Find out what GSS mechanism to use from <code>http.negotiate.mechanism.oid</code>,

     *     defaults SPNEGO

     * <li>Creating the GSSName for the target host, "HTTP/"+hostname

     * <li>Creating GSSContext

     * <li>A first call to initSecContext</ul>

     * @param hostname name of peer server

     * @param scheme auth scheme requested, Negotiate ot Kerberos

     * @throws GSSException if any JGSS-API call fails

     */

    private void init(final String hostname, String scheme) throws GSSException {

        // "1.2.840.113554.1.2.2" Kerberos

        // "1.3.6.1.5.5.2" SPNEGO

        final Oid oid;

        if (scheme.equalsIgnoreCase("Kerberos")) {

            // we can only use Kerberos mech when the scheme is kerberos

            oid = GSSUtil.GSS_KRB5_MECH_OID;

        } else {

            String pref = java.security.AccessController.doPrivileged(

                    new java.security.PrivilegedAction<String>() {

                        public String run() {

                            return System.getProperty(

                                "http.auth.preference",

                                "spnego");

                        }

                    });

            if (pref.equalsIgnoreCase("kerberos")) {

                oid = GSSUtil.GSS_KRB5_MECH_OID;

            } else {

                // currently there is no 3rd mech we can use

                oid = GSSUtil.GSS_SPNEGO_MECH_OID;

            }

        }

        GSSManagerImpl manager = new GSSManagerImpl(

                GSSUtil.CALLER_HTTP_NEGOTIATE);

        context = manager.createContext(serverName,

                                        oid,

                                        null,

                                        GSSContext.DEFAULT_LIFETIME);

        // In order to support credential delegation in HTTP/SPNEGO,

        // we always request it before initSecContext. The current

        // implementation will check the OK-AS-DELEGATE flag inside

        // the service ticket of the web server, and only enable

        // delegation when this flag is set. This check is only

        // performed when the GSS caller is CALLER_HTTP_NEGOTIATE,

        // so all other normal GSS-API calls are not affected.

        context.requestCredDeleg(true);

        oneToken = context.initSecContext(new byte[0], 0, 0);

    }

    /**

     * Constructor

     * @param hostname name of peer server

     * @param scheme auth scheme requested, Negotiate ot Kerberos

     * @throws java.io.IOException If negotiator cannot be constructed

     */

    public NegotiatorImpl(String hostname, String scheme) throws IOException {

        try {

            init(hostname, scheme);

        } catch (GSSException e) {

            if (DEBUG) {

                System.out.println("Negotiate support not initiated, will fallback to other scheme if allowed. Reason:");

                e.printStackTrace();

            }

            IOException ioe = new IOException("Negotiate support not initiated");

            ioe.initCause(e);

            throw ioe;

        }

    }

    /**

     * Return the first token of GSS, in SPNEGO, it's called NegTokenInit

     * @return the first token

     */

    public byte[] firstToken() {

        return oneToken;

    }

    /**

     * Return the rest tokens of GSS, in SPNEGO, it's called NegTokenTarg

     * @param token the token received from server

     * @return the next token

     * @throws java.io.IOException if the token cannot be created successfully

     */

    public byte[] nextToken(byte[] token) throws IOException {

        try {

            return context.initSecContext(token, 0, token.length);

        } catch (GSSException e) {

            if (DEBUG) {

                System.out.println("Negotiate support cannot continue. Reason:");

                e.printStackTrace();

            }

            IOException ioe = new IOException("Negotiate support cannot continue");

            ioe.initCause(e);

            throw ioe;

        }

    }

}