/*

 * Copyright 2003-2007 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.ssl;

import java.io.*;

import java.nio.*;

import javax.net.ssl.*;

import javax.crypto.BadPaddingException;

import sun.misc.HexDumpEncoder;

/**

 * Wrapper class around InputRecord.

 *

 * Application data is kept external to the InputRecord,

 * but handshake data (alert/change_cipher_spec/handshake) will

 * be kept internally in the ByteArrayInputStream.

 *

 * @author Brad Wetmore

 */

final class EngineInputRecord extends InputRecord {

    private SSLEngineImpl engine;

    /*

     * A dummy ByteBuffer we'll pass back even when the data

     * is stored internally.  It'll never actually be used.

     */

    static private ByteBuffer tmpBB = ByteBuffer.allocate(0);

    /*

     * Flag to tell whether the last read/parsed data resides

     * internal in the ByteArrayInputStream, or in the external

     * buffers.

     */

    private boolean internalData;

    EngineInputRecord(SSLEngineImpl engine) {

        super();

        this.engine = engine;

    }

    byte contentType() {

        if (internalData) {

            return super.contentType();

        } else {

            return ct_application_data;

        }

    }

    /*

     * Check if there is enough inbound data in the ByteBuffer

     * to make a inbound packet.  Look for both SSLv2 and SSLv3.

     *

     * @return -1 if there are not enough bytes to tell (small header),

     */

    int bytesInCompletePacket(ByteBuffer buf) throws SSLException {

        /*

         * SSLv2 length field is in bytes 0/1

         * SSLv3/TLS length field is in bytes 3/4

         */

        if (buf.remaining() < 5) {

            return -1;

        }

        int pos = buf.position();

        byte byteZero = buf.get(pos);

        int len = 0;

        /*

         * If we have already verified previous packets, we can

         * ignore the verifications steps, and jump right to the

         * determination.  Otherwise, try one last hueristic to

         * see if it's SSL/TLS.

         */

        if (formatVerified ||

                (byteZero == ct_handshake) ||

                (byteZero == ct_alert)) {

            /*

             * Last sanity check that it's not a wild record

             */

            ProtocolVersion recordVersion =

                ProtocolVersion.valueOf(buf.get(pos + 1), buf.get(pos + 2));

            // Check if too old (currently not possible)

            // or if the major version does not match.

            // The actual version negotiation is in the handshaker classes

            if ((recordVersion.v < ProtocolVersion.MIN.v)

                    || (recordVersion.major > ProtocolVersion.MAX.major)) {

                throw new SSLException(

                    "Unsupported record version " + recordVersion);

            }

            /*

             * Reasonably sure this is a V3, disable further checks.

             * We can't do the same in the v2 check below, because

             * read still needs to parse/handle the v2 clientHello.

             */

            formatVerified = true;

            /*

             * One of the SSLv3/TLS message types.

             */

            len = ((buf.get(pos + 3) & 0xff) << 8) +

                (buf.get(pos + 4) & 0xff) + headerSize;

        } else {

            /*

             * Must be SSLv2 or something unknown.

             * Check if it's short (2 bytes) or

             * long (3) header.

             *

             * Internals can warn about unsupported SSLv2

             */

            boolean isShort = ((byteZero & 0x80) != 0);

            if (isShort &&

                    ((buf.get(pos + 2) == 1) || buf.get(pos + 2) == 4)) {

                ProtocolVersion recordVersion =

                    ProtocolVersion.valueOf(buf.get(pos + 3), buf.get(pos + 4));

                // Check if too old (currently not possible)

                // or if the major version does not match.

                // The actual version negotiation is in the handshaker classes

                if ((recordVersion.v < ProtocolVersion.MIN.v)

                        || (recordVersion.major > ProtocolVersion.MAX.major)) {

                    // if it's not SSLv2, we're out of here.

                    if (recordVersion.v != ProtocolVersion.SSL20Hello.v) {

                        throw new SSLException(

                            "Unsupported record version " + recordVersion);

                    }

                }

                /*

                 * Client or Server Hello

                 */

                int mask = (isShort ? 0x7f : 0x3f);

                len = ((byteZero & mask) << 8) + (buf.get(pos + 1) & 0xff) +

                    (isShort ? 2 : 3);

            } else {

                // Gobblygook!

                throw new SSLException(

                    "Unrecognized SSL message, plaintext connection?");

            }

        }

        return len;

    }

    /*

     * Verifies and removes the MAC value.  Returns true if

     * the MAC checks out OK.

     *

     * On entry:

     *     position = beginning of app/MAC data

     *     limit = end of MAC data.

     *

     * On return:

     *     position = beginning of app data

     *     limit = end of app data

     */

    boolean checkMAC(MAC signer, ByteBuffer bb) {

        if (internalData) {

            return checkMAC(signer);

        }

        int len = signer.MAClen();

        if (len == 0) { // no mac

            return true;

        }

        /*

         * Grab the original limit

         */

        int lim = bb.limit();

        /*

         * Delineate the area to apply a MAC on.

         */

        int macData = lim - len;

        bb.limit(macData);

        byte[] mac = signer.compute(contentType(), bb);

        if (len != mac.length) {

            throw new RuntimeException("Internal MAC error");

        }

        /*

         * Delineate the MAC values, position was already set

         * by doing the compute above.

         *

         * We could zero the MAC area, but not much useful information

         * there anyway.

         */

        bb.position(macData);

        bb.limit(lim);

        try {

            for (int i = 0; i < len; i++) {

                if (bb.get() != mac[i]) {  // No BB.equals(byte []); !

                    return false;

                }

            }

            return true;

        } finally {

            /*

             * Position to the data.

             */

            bb.rewind();

            bb.limit(macData);

        }

    }

    /*

     * Pass the data down if it's internally cached, otherwise

     * do it here.

     *

     * If internal data, data is decrypted internally.

     *

     * If external data(app), return a new ByteBuffer with data to

     * process.

     */

    ByteBuffer decrypt(CipherBox box, ByteBuffer bb)

            throws BadPaddingException {

        if (internalData) {

            decrypt(box);

            return tmpBB;

        }

        box.decrypt(bb);

        bb.rewind();

        return bb.slice();

    }

    /*

     * Override the actual write below.  We do things this way to be

     * consistent with InputRecord.  InputRecord may try to write out

     * data to the peer, and *then* throw an Exception.  This forces

     * data to be generated/output before the exception is ever

     * generated.

     */

    void writeBuffer(OutputStream s, byte [] buf, int off, int len)

            throws IOException {

        /*

         * Copy data out of buffer, it's ready to go.

         */

        ByteBuffer netBB = (ByteBuffer)

            (ByteBuffer.allocate(len).put(buf, 0, len).flip());

        engine.writer.putOutboundDataSync(netBB);

    }

    /*

     * Delineate or read a complete packet from src.

     *

     * If internal data (hs, alert, ccs), the data is read and

     * stored internally.

     *

     * If external data (app), return a new ByteBuffer which points

     * to the data to process.

     */

    ByteBuffer read(ByteBuffer srcBB) throws IOException {

        /*

         * Could have a src == null/dst == null check here,

         * but that was already checked by SSLEngine.unwrap before

         * ever attempting to read.

         */

        /*

         * If we have anything besides application data,

         * or if we haven't even done the initial v2 verification,

         * we send this down to be processed by the underlying

         * internal cache.

         */

        if (!formatVerified ||

                (srcBB.get(srcBB.position()) != ct_application_data)) {

            internalData = true;

            read(new ByteBufferInputStream(srcBB), (OutputStream) null);

            return tmpBB;

        }

        internalData = false;

        int srcPos = srcBB.position();

        int srcLim = srcBB.limit();

        ProtocolVersion recordVersion = ProtocolVersion.valueOf(

                srcBB.get(srcPos + 1), srcBB.get(srcPos + 2));

        // Check if too old (currently not possible)

        // or if the major version does not match.

        // The actual version negotiation is in the handshaker classes

        if ((recordVersion.v < ProtocolVersion.MIN.v)

                || (recordVersion.major > ProtocolVersion.MAX.major)) {

            throw new SSLException(

                "Unsupported record version " + recordVersion);

        }

        /*

         * It's really application data.  How much to consume?

         * Jump over the header.

         */

        int len = bytesInCompletePacket(srcBB);

        assert(len > 0);

        if (debug != null && Debug.isOn("packet")) {

            try {

                HexDumpEncoder hd = new HexDumpEncoder();

                srcBB.limit(srcPos + len);

                ByteBuffer bb = srcBB.duplicate();  // Use copy of BB

                System.out.println("[Raw read (bb)]: length = " + len);

                hd.encodeBuffer(bb, System.out);

            } catch (IOException e) { }

        }

        // Demarcate past header to end of packet.

        srcBB.position(srcPos + headerSize);

        srcBB.limit(srcPos + len);

        // Protect remainder of buffer, create slice to actually

        // operate on.

        ByteBuffer bb = srcBB.slice();

        srcBB.position(srcBB.limit());

        srcBB.limit(srcLim);

        return bb;

    }

}