/*

 * Copyright (c) 2005, 2014, 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.  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

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 */

package sun.net.www.protocol.http;

import java.net.URL;

import java.io.IOException;

import java.net.Authenticator.RequestorType;

import java.util.Base64;

import java.util.HashMap;

import sun.net.www.HeaderParser;

import sun.util.logging.PlatformLogger;

import static sun.net.www.protocol.http.AuthScheme.NEGOTIATE;

import static sun.net.www.protocol.http.AuthScheme.KERBEROS;

/**

 * NegotiateAuthentication:

 *

 * @author weijun.wang@sun.com

 * @since 1.6

 */

class NegotiateAuthentication extends AuthenticationInfo {

    private static final long serialVersionUID = 100L;

    private static final PlatformLogger logger = HttpURLConnection.getHttpLogger();

    final private HttpCallerInfo hci;

    // These maps are used to manage the GSS availability for diffrent

    // hosts. The key for both maps is the host name.

    // <code>supported</code> is set when isSupported is checked,

    // if it's true, a cached Negotiator is put into <code>cache</code>.

    // the cache can be used only once, so after the first use, it's cleaned.

    static HashMap <String, Boolean> supported = null;

    static HashMap <String, Negotiator> cache = null;

    // The HTTP Negotiate Helper

    private Negotiator negotiator = null;

   /**

    * Constructor used for both WWW and proxy entries.

    * @param hci a schemed object.

    */

    public NegotiateAuthentication(HttpCallerInfo hci) {

        super(RequestorType.PROXY==hci.authType ? PROXY_AUTHENTICATION : SERVER_AUTHENTICATION,

              hci.scheme.equalsIgnoreCase("Negotiate") ? NEGOTIATE : KERBEROS,

              hci.url,

              "");

        this.hci = hci;

    }

    /**

     * @return true if this authentication supports preemptive authorization

     */

    @Override

    public boolean supportsPreemptiveAuthorization() {

        return false;

    }

    /**

     * Find out if the HttpCallerInfo supports Negotiate protocol.

     * @return true if supported

     */

    public static boolean isSupported(HttpCallerInfo hci) {

        ClassLoader loader = null;

        try {

            loader = Thread.currentThread().getContextClassLoader();

        } catch (SecurityException se) {

            if (logger.isLoggable(PlatformLogger.Level.FINER)) {

                logger.finer("NegotiateAuthentication: " +

                    "Attempt to get the context class loader failed - " + se);

            }

        }

        if (loader != null) {

            // Lock on the class loader instance to avoid the deadlock engaging

            // the lock in "ClassLoader.loadClass(String, boolean)" method.

            synchronized (loader) {

                return isSupportedImpl(hci);

            }

        }

        return isSupportedImpl(hci);

    }

    /**

     * Find out if the HttpCallerInfo supports Negotiate protocol. In order to

     * find out yes or no, an initialization of a Negotiator object against it

     * is tried. The generated object will be cached under the name of ths

     * hostname at a success try.<br>

     *

     * If this method is called for the second time on an HttpCallerInfo with

     * the same hostname, the answer is retrieved from cache.

     *

     * @return true if supported

     */

    private static synchronized boolean isSupportedImpl(HttpCallerInfo hci) {

        if (supported == null) {

            supported = new HashMap <String, Boolean>();

            cache = new HashMap <String, Negotiator>();

        }

        String hostname = hci.host;

        hostname = hostname.toLowerCase();

        if (supported.containsKey(hostname)) {

            return supported.get(hostname);

        }

        Negotiator neg = Negotiator.getNegotiator(hci);

        if (neg != null) {

            supported.put(hostname, true);

            // the only place cache.put is called. here we can make sure

            // the object is valid and the oneToken inside is not null

            cache.put(hostname, neg);

            return true;

        } else {

            supported.put(hostname, false);

            return false;

        }

    }

    /**

     * Not supported. Must use the setHeaders() method

     */

    @Override

    public String getHeaderValue(URL url, String method) {

        throw new RuntimeException ("getHeaderValue not supported");

    }

    /**

     * Check if the header indicates that the current auth. parameters are stale.

     * If so, then replace the relevant field with the new value

     * and return true. Otherwise return false.

     * returning true means the request can be retried with the same userid/password

     * returning false means we have to go back to the user to ask for a new

     * username password.

     */

    @Override

    public boolean isAuthorizationStale (String header) {

        return false; /* should not be called for Negotiate */

    }

    /**

     * Set header(s) on the given connection.

     * @param conn The connection to apply the header(s) to

     * @param p A source of header values for this connection, not used because

     *          HeaderParser converts the fields to lower case, use raw instead

     * @param raw The raw header field.

     * @return true if all goes well, false if no headers were set.

     */

    @Override

    public synchronized boolean setHeaders(HttpURLConnection conn, HeaderParser p, String raw) {

        try {

            String response;

            byte[] incoming = null;

            String[] parts = raw.split("\\s+");

            if (parts.length > 1) {

                incoming = Base64.getDecoder().decode(parts[1]);

            }

            response = hci.scheme + " " + Base64.getEncoder().encodeToString(

                        incoming==null?firstToken():nextToken(incoming));

            conn.setAuthenticationProperty(getHeaderName(), response);

            return true;

        } catch (IOException e) {

            return false;

        }

    }

    /**

     * return the first token.

     * @returns the token

     * @throws IOException if <code>Negotiator.getNegotiator()</code> or

     *                     <code>Negotiator.firstToken()</code> failed.

     */

    private byte[] firstToken() throws IOException {

        negotiator = null;

        if (cache != null) {

            synchronized(cache) {

                negotiator = cache.get(getHost());

                if (negotiator != null) {

                    cache.remove(getHost()); // so that it is only used once

                }

            }

        }

        if (negotiator == null) {

            negotiator = Negotiator.getNegotiator(hci);

            if (negotiator == null) {

                IOException ioe = new IOException("Cannot initialize Negotiator");

                throw ioe;

            }

        }

        return negotiator.firstToken();

    }

    /**

     * return more tokens

     * @param token the token to be fed into <code>negotiator.nextToken()</code>

     * @returns the token

     * @throws IOException if <code>negotiator.nextToken()</code> throws Exception.

     *  May happen if the input token is invalid.

     */

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

        return negotiator.nextToken(token);

    }

    // MS will send a final WWW-Authenticate even if the status is already

    // 200 OK. The token can be fed into initSecContext() again to determine

    // if the server can be trusted. This is not the same concept as Digest's

    // Authentication-Info header.

    //

    // Currently we ignore this header.

}