/*
 * Copyright 2004-2006 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.security.jgss.krb5;

import org.ietf.jgss.*;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.IOException;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;

/**
 * This class represents the new format of GSS MIC tokens, as specified
 * in draft-ietf-krb-wg-gssapi-cfx-07.txt
 *
 * MIC tokens = { 16-byte token-header |  HMAC }
 * where HMAC is on { plaintext | 16-byte token-header }
 *
 * @author Seema Malkani
 */

class MicToken_v2 extends MessageToken_v2 {

    public MicToken_v2(Krb5Context context,
                  byte[] tokenBytes, int tokenOffset, int tokenLen,
                  MessageProp prop)  throws GSSException {
        super(Krb5Token.MIC_ID_v2, context,
          tokenBytes, tokenOffset, tokenLen, prop);
    }

    public MicToken_v2(Krb5Context context,
                   InputStream is, MessageProp prop)
    throws GSSException {
        super(Krb5Token.MIC_ID_v2, context, is, prop);
    }

    public void verify(byte[] data, int offset, int len) throws GSSException {
        if (!verifySign(data, offset, len))
            throw new GSSException(GSSException.BAD_MIC, -1,
                         "Corrupt checksum or sequence number in MIC token");
    }

    public void verify(InputStream data) throws GSSException {

        byte[] dataBytes = null;
        try {
            dataBytes = new byte[data.available()];
            data.read(dataBytes);
        } catch (IOException e) {
            // Error reading application data
            throw new GSSException(GSSException.BAD_MIC, -1,
                "Corrupt checksum or sequence number in MIC token");
        }
        verify(dataBytes, 0, dataBytes.length);
    }

    public MicToken_v2(Krb5Context context, MessageProp prop,
                  byte[] data, int pos, int len)
        throws GSSException {
        super(Krb5Token.MIC_ID_v2, context);

        //      debug("Application data to MicToken verify is [" +
        //            getHexBytes(data, pos, len) + "]\n");
        if (prop == null) prop = new MessageProp(0, false);
        genSignAndSeqNumber(prop, data, pos, len);
    }

    public MicToken_v2(Krb5Context context, MessageProp prop, InputStream data)
        throws GSSException, IOException {

        super(Krb5Token.MIC_ID_v2, context);
        byte[] dataBytes = new byte[data.available()];
        data.read(dataBytes);

        // debug("Application data to MicToken cons is [" +
        //     getHexBytes(dataBytes) + "]\n");
        if (prop == null) prop = new MessageProp(0, false);
        genSignAndSeqNumber(prop, dataBytes, 0, dataBytes.length);
    }

    public int encode(byte[] outToken, int offset)
        throws IOException, GSSException {

        // Token  is small
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        super.encode(bos);
        byte[] token = bos.toByteArray();
        System.arraycopy(token, 0, outToken, offset, token.length);
        return token.length;
    }

    public byte[] encode() throws IOException, GSSException {

        // XXX Fine tune this initial size
        ByteArrayOutputStream bos = new ByteArrayOutputStream(50);
        encode(bos);
        return bos.toByteArray();
    }
}