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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 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).
 *
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 * 2 along with this work; if not, write to the Free Software Foundation,
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 *
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package sun.security.ssl;

import java.io.ByteArrayOutputStream;
import java.io.Closeable;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import sun.security.ssl.SSLCipher.SSLWriteCipher;

OutputRecord takes care of the management of SSL/(D)TLS output records, including buffering, encryption, handshake messages marshal, etc. 
Author:
David Brownell/**
 * {@code OutputRecord} takes care of the management of SSL/(D)TLS
 * output records, including buffering, encryption, handshake
 * messages marshal, etc.
 *
 * @author David Brownell
 */
abstract class OutputRecord
        extends ByteArrayOutputStream implements Record, Closeable {
    SSLWriteCipher              writeCipher;
    // Needed for KeyUpdate, used after Handshake.Finished
    TransportContext            tc;

    final HandshakeHash         handshakeHash;
    boolean                     firstMessage;

    // current protocol version, sent as record version
    ProtocolVersion             protocolVersion;

    // version for the ClientHello message. Only relevant if this is a
    // client handshake record. If set to ProtocolVersion.SSL20Hello,
    // the V3 client hello is converted to V2 format.
    ProtocolVersion             helloVersion;

    // Is it the first application record to write?
    boolean                     isFirstAppOutputRecord = true;

    // packet size
    int                         packetSize;

    // fragment size
    private int                 fragmentSize;

    // closed or not?
    volatile boolean            isClosed;

    /*
     * Mappings from V3 cipher suite encodings to their pure V2 equivalents.
     * This is taken from the SSL V3 specification, Appendix E.
     */
    private static final int[] V3toV2CipherMap1 =
        {-1, -1, -1, 0x02, 0x01, -1, 0x04, 0x05, -1, 0x06, 0x07};
    private static final int[] V3toV2CipherMap3 =
        {-1, -1, -1, 0x80, 0x80, -1, 0x80, 0x80, -1, 0x40, 0xC0};
    private static final byte[] HANDSHAKE_MESSAGE_KEY_UPDATE =
        {SSLHandshake.KEY_UPDATE.id, 0x00, 0x00, 0x01, 0x00};

    OutputRecord(HandshakeHash handshakeHash, SSLWriteCipher writeCipher) {
        this.writeCipher = writeCipher;
        this.firstMessage = true;
        this.fragmentSize = Record.maxDataSize;

        this.handshakeHash = handshakeHash;

        // Please set packetSize and protocolVersion in the implementation.
    }

    synchronized void setVersion(ProtocolVersion protocolVersion) {
        this.protocolVersion = protocolVersion;
    }

    /*
     * Updates helloVersion of this record.
     */
    synchronized void setHelloVersion(ProtocolVersion helloVersion) {
        this.helloVersion = helloVersion;
    }

    /*
     * Return true iff the record is empty -- to avoid doing the work
     * of sending empty records over the network.
     */
    boolean isEmpty() {
        return false;
    }

    synchronized boolean seqNumIsHuge() {
        return (writeCipher.authenticator != null) &&
                        writeCipher.authenticator.seqNumIsHuge();
    }

    // SSLEngine and SSLSocket
    abstract void encodeAlert(byte level, byte description) throws IOException;

    // SSLEngine and SSLSocket
    abstract void encodeHandshake(byte[] buffer,
            int offset, int length) throws IOException;

    // SSLEngine and SSLSocket
    abstract void encodeChangeCipherSpec() throws IOException;

    // apply to SSLEngine only
    Ciphertext encode(
        ByteBuffer[] srcs, int srcsOffset, int srcsLength,
        ByteBuffer[] dsts, int dstsOffset, int dstsLength) throws IOException {

        throw new UnsupportedOperationException();
    }

    // apply to SSLEngine only
    void encodeV2NoCipher() throws IOException {
        throw new UnsupportedOperationException();
    }

    // apply to SSLSocket only
    void deliver(
            byte[] source, int offset, int length) throws IOException {
        throw new UnsupportedOperationException();
    }

    // apply to SSLSocket only
    void setDeliverStream(OutputStream outputStream) {
        throw new UnsupportedOperationException();
    }

    // Change write ciphers, may use change_cipher_spec record.
    synchronized void changeWriteCiphers(SSLWriteCipher writeCipher,
            boolean useChangeCipherSpec) throws IOException {
        if (isClosed()) {
            if (SSLLogger.isOn && SSLLogger.isOn("ssl")) {
                SSLLogger.warning("outbound has closed, ignore outbound " +
                    "change_cipher_spec message");
            }
            return;
        }

        if (useChangeCipherSpec) {
            encodeChangeCipherSpec();
        }

        /*
         * Dispose of any intermediate state in the underlying cipher.
         * For PKCS11 ciphers, this will release any attached sessions,
         * and thus make finalization faster.
         *
         * Since MAC's doFinal() is called for every SSL/TLS packet, it's
         * not necessary to do the same with MAC's.
         */
        writeCipher.dispose();

        this.writeCipher = writeCipher;
        this.isFirstAppOutputRecord = true;
    }

    // Change write ciphers using key_update handshake message.
    synchronized void changeWriteCiphers(SSLWriteCipher writeCipher,
            byte keyUpdateRequest) throws IOException {
        if (isClosed()) {
            if (SSLLogger.isOn && SSLLogger.isOn("ssl")) {
                SSLLogger.warning("outbound has closed, ignore outbound " +
                    "key_update handshake message");
            }
            return;
        }

        // encode the handshake message, KeyUpdate
        byte[] hm = HANDSHAKE_MESSAGE_KEY_UPDATE.clone();
        hm[hm.length - 1] = keyUpdateRequest;
        encodeHandshake(hm, 0, hm.length);
        flush();

        // Dispose of any intermediate state in the underlying cipher.
        writeCipher.dispose();

        this.writeCipher = writeCipher;
        this.isFirstAppOutputRecord = true;
    }

    synchronized void changePacketSize(int packetSize) {
        this.packetSize = packetSize;
    }

    synchronized void changeFragmentSize(int fragmentSize) {
        this.fragmentSize = fragmentSize;
    }

    synchronized int getMaxPacketSize() {
        return packetSize;
    }

    // apply to DTLS SSLEngine
    void initHandshaker() {
        // blank
    }

    // apply to DTLS SSLEngine
    void finishHandshake() {
        // blank
    }

    // apply to DTLS SSLEngine
    void launchRetransmission() {
        // blank
    }

    @Override
    public synchronized void close() throws IOException {
        if (isClosed) {
            return;
        }

        isClosed = true;
        writeCipher.dispose();
    }

    boolean isClosed() {
        return isClosed;
    }

    //
    // shared helpers
    //

    private static final class T13PaddingHolder {
        private static final byte[] zeros = new byte[16];
    }

    int calculateFragmentSize(int fragmentLimit) {
        if (fragmentSize > 0) {
            fragmentLimit = Math.min(fragmentLimit, fragmentSize);
        }

        if (protocolVersion.useTLS13PlusSpec()) {
            // No negative integer checking as the fragment capacity should
            // have been ensured.
            return fragmentLimit -  T13PaddingHolder.zeros.length - 1;
        }

        return fragmentLimit;
    }

    // Encrypt a fragment and wrap up a record.
    //
    // To be consistent with the spec of SSLEngine.wrap() methods, the
    // destination ByteBuffer's position is updated to reflect the amount
    // of data produced.  The limit remains the same.
    static long encrypt(
            SSLWriteCipher encCipher, byte contentType, ByteBuffer destination,
            int headerOffset, int dstLim, int headerSize,
            ProtocolVersion protocolVersion) {
        boolean isDTLS = protocolVersion.isDTLS;
        if (isDTLS) {
            if (protocolVersion.useTLS13PlusSpec()) {
                return d13Encrypt(encCipher,
                        contentType, destination, headerOffset,
                        dstLim, headerSize, protocolVersion);
            } else {
                return d10Encrypt(encCipher,
                        contentType, destination, headerOffset,
                        dstLim, headerSize, protocolVersion);
            }
        } else {
            if (protocolVersion.useTLS13PlusSpec()) {
                return t13Encrypt(encCipher,
                        contentType, destination, headerOffset,
                        dstLim, headerSize, protocolVersion);
            } else {
                return t10Encrypt(encCipher,
                        contentType, destination, headerOffset,
                        dstLim, headerSize, protocolVersion);
            }
        }
    }

    private static long d13Encrypt(
            SSLWriteCipher encCipher, byte contentType, ByteBuffer destination,
            int headerOffset, int dstLim, int headerSize,
            ProtocolVersion protocolVersion) {
        throw new UnsupportedOperationException("Not supported yet.");
    }

    private static long d10Encrypt(
            SSLWriteCipher encCipher, byte contentType, ByteBuffer destination,
            int headerOffset, int dstLim, int headerSize,
            ProtocolVersion protocolVersion) {
        byte[] sequenceNumber = encCipher.authenticator.sequenceNumber();
        encCipher.encrypt(contentType, destination);

        // Finish out the record header.
        int fragLen = destination.limit() - headerOffset - headerSize;

        destination.put(headerOffset, contentType);         // content type
        destination.put(headerOffset + 1, protocolVersion.major);
        destination.put(headerOffset + 2, protocolVersion.minor);

        // epoch and sequence_number
        destination.put(headerOffset + 3, sequenceNumber[0]);
        destination.put(headerOffset + 4, sequenceNumber[1]);
        destination.put(headerOffset + 5, sequenceNumber[2]);
        destination.put(headerOffset + 6, sequenceNumber[3]);
        destination.put(headerOffset + 7, sequenceNumber[4]);
        destination.put(headerOffset + 8, sequenceNumber[5]);
        destination.put(headerOffset + 9, sequenceNumber[6]);
        destination.put(headerOffset + 10, sequenceNumber[7]);

        // fragment length
        destination.put(headerOffset + 11, (byte)(fragLen >> 8));
        destination.put(headerOffset + 12, (byte)fragLen);

        // Update destination position to reflect the amount of data produced.
        destination.position(destination.limit());

        return Authenticator.toLong(sequenceNumber);
    }

    private static long t13Encrypt(
            SSLWriteCipher encCipher, byte contentType, ByteBuffer destination,
            int headerOffset, int dstLim, int headerSize,
            ProtocolVersion protocolVersion) {
        if (!encCipher.isNullCipher()) {
            // inner plaintext, using zero length padding.
            int endOfPt = destination.limit();
            int startOfPt = destination.position();
            destination.position(endOfPt);
            destination.limit(endOfPt + 1 + T13PaddingHolder.zeros.length);
            destination.put(contentType);
            destination.put(T13PaddingHolder.zeros);
            destination.position(startOfPt);
        }

        // use the right TLSCiphertext.opaque_type and legacy_record_version
        ProtocolVersion pv = protocolVersion;
        if (!encCipher.isNullCipher()) {
            pv = ProtocolVersion.TLS12;
            contentType = ContentType.APPLICATION_DATA.id;
        } else if (protocolVersion.useTLS13PlusSpec()) {
            pv = ProtocolVersion.TLS12;
        }

        byte[] sequenceNumber = encCipher.authenticator.sequenceNumber();
        encCipher.encrypt(contentType, destination);

        // Finish out the record header.
        int fragLen = destination.limit() - headerOffset - headerSize;
        destination.put(headerOffset, contentType);
        destination.put(headerOffset + 1, pv.major);
        destination.put(headerOffset + 2, pv.minor);

        // fragment length
        destination.put(headerOffset + 3, (byte)(fragLen >> 8));
        destination.put(headerOffset + 4, (byte)fragLen);

        // Update destination position to reflect the amount of data produced.
        destination.position(destination.limit());

        return Authenticator.toLong(sequenceNumber);
    }

    private static long t10Encrypt(
            SSLWriteCipher encCipher, byte contentType, ByteBuffer destination,
            int headerOffset, int dstLim, int headerSize,
            ProtocolVersion protocolVersion) {
        byte[] sequenceNumber = encCipher.authenticator.sequenceNumber();
        encCipher.encrypt(contentType, destination);

        // Finish out the record header.
        int fragLen = destination.limit() - headerOffset - headerSize;

        destination.put(headerOffset, contentType);         // content type
        destination.put(headerOffset + 1, protocolVersion.major);
        destination.put(headerOffset + 2, protocolVersion.minor);

        // fragment length
        destination.put(headerOffset + 3, (byte)(fragLen >> 8));
        destination.put(headerOffset + 4, (byte)fragLen);

        // Update destination position to reflect the amount of data produced.
        destination.position(destination.limit());

        return Authenticator.toLong(sequenceNumber);
    }

    // Encrypt a fragment and wrap up a record.
    //
    // Uses the internal expandable buf variable and the current
    // protocolVersion variable.
    long encrypt(
            SSLWriteCipher encCipher, byte contentType, int headerSize) {
        if (protocolVersion.useTLS13PlusSpec()) {
            return t13Encrypt(encCipher, contentType, headerSize);
        } else {
            return t10Encrypt(encCipher, contentType, headerSize);
        }
    }

    private long t13Encrypt(
            SSLWriteCipher encCipher, byte contentType, int headerSize) {
        if (!encCipher.isNullCipher()) {
            // inner plaintext
            write(contentType);
            write(T13PaddingHolder.zeros, 0, T13PaddingHolder.zeros.length);
        }

        byte[] sequenceNumber = encCipher.authenticator.sequenceNumber();
        int position = headerSize;
        int contentLen = count - position;

        // ensure the capacity
        int requiredPacketSize =
                encCipher.calculatePacketSize(contentLen, headerSize);
        if (requiredPacketSize > buf.length) {
            byte[] newBuf = new byte[requiredPacketSize];
            System.arraycopy(buf, 0, newBuf, 0, count);
            buf = newBuf;
        }

        // use the right TLSCiphertext.opaque_type and legacy_record_version
        ProtocolVersion pv = protocolVersion;
        if (!encCipher.isNullCipher()) {
            pv = ProtocolVersion.TLS12;
            contentType = ContentType.APPLICATION_DATA.id;
        } else {
            pv = ProtocolVersion.TLS12;
        }

        ByteBuffer destination = ByteBuffer.wrap(buf, position, contentLen);
        count = headerSize + encCipher.encrypt(contentType, destination);

        // Fill out the header, write it and the message.
        int fragLen = count - headerSize;

        buf[0] = contentType;
        buf[1] = pv.major;
        buf[2] = pv.minor;
        buf[3] = (byte)((fragLen >> 8) & 0xFF);
        buf[4] = (byte)(fragLen & 0xFF);

        return Authenticator.toLong(sequenceNumber);
    }

    private long t10Encrypt(
            SSLWriteCipher encCipher, byte contentType, int headerSize) {
        byte[] sequenceNumber = encCipher.authenticator.sequenceNumber();
        int position = headerSize + writeCipher.getExplicitNonceSize();
        int contentLen = count - position;

        // ensure the capacity
        int requiredPacketSize =
                encCipher.calculatePacketSize(contentLen, headerSize);
        if (requiredPacketSize > buf.length) {
            byte[] newBuf = new byte[requiredPacketSize];
            System.arraycopy(buf, 0, newBuf, 0, count);
            buf = newBuf;
        }
        ByteBuffer destination = ByteBuffer.wrap(buf, position, contentLen);
        count = headerSize + encCipher.encrypt(contentType, destination);

        // Fill out the header, write it and the message.
        int fragLen = count - headerSize;
        buf[0] = contentType;
        buf[1] = protocolVersion.major;
        buf[2] = protocolVersion.minor;
        buf[3] = (byte)((fragLen >> 8) & 0xFF);
        buf[4] = (byte)(fragLen & 0xFF);

        return Authenticator.toLong(sequenceNumber);
    }

    static ByteBuffer encodeV2ClientHello(
            byte[] fragment, int offset, int length) throws IOException {
        int v3SessIdLenOffset = offset + 34;      //  2: client_version
                                                  // 32: random

        int v3SessIdLen = fragment[v3SessIdLenOffset];
        int v3CSLenOffset = v3SessIdLenOffset + 1 + v3SessIdLen;
        int v3CSLen = ((fragment[v3CSLenOffset] & 0xff) << 8) +
                       (fragment[v3CSLenOffset + 1] & 0xff);
        int cipherSpecs = v3CSLen / 2;        // 2: cipher spec size

        // Estimate the max V2ClientHello message length
        //
        // 11: header size
        // (cipherSpecs * 6): cipher_specs
        //    6: one cipher suite may need 6 bytes, see V3toV2CipherSuite.
        // 3: placeholder for the TLS_EMPTY_RENEGOTIATION_INFO_SCSV
        //    signaling cipher suite
        // 32: challenge size
        int v2MaxMsgLen = 11 + (cipherSpecs * 6) + 3 + 32;

        // Create a ByteBuffer backed by an accessible byte array.
        byte[] dstBytes = new byte[v2MaxMsgLen];
        ByteBuffer dstBuf = ByteBuffer.wrap(dstBytes);

        /*
         * Copy over the cipher specs. We don't care about actually
         * translating them for use with an actual V2 server since
         * we only talk V3.  Therefore, just copy over the V3 cipher
         * spec values with a leading 0.
         */
        int v3CSOffset = v3CSLenOffset + 2;   // skip length field
        int v2CSLen = 0;

        dstBuf.position(11);
        boolean containsRenegoInfoSCSV = false;
        for (int i = 0; i < cipherSpecs; i++) {
            byte byte1, byte2;

            byte1 = fragment[v3CSOffset++];
            byte2 = fragment[v3CSOffset++];
            v2CSLen += V3toV2CipherSuite(dstBuf, byte1, byte2);
            if (!containsRenegoInfoSCSV &&
                    byte1 == (byte)0x00 && byte2 == (byte)0xFF) {
                containsRenegoInfoSCSV = true;
            }
        }

        if (!containsRenegoInfoSCSV) {
            v2CSLen += V3toV2CipherSuite(dstBuf, (byte)0x00, (byte)0xFF);
        }

        /*
         * Copy in the nonce.
         */
        dstBuf.put(fragment, (offset + 2), 32);

        /*
         * Build the first part of the V3 record header from the V2 one
         * that's now buffered up.  (Lengths are fixed up later).
         */
        int msgLen = dstBuf.position() - 2;   // Exclude the legth field itself
        dstBuf.position(0);
        dstBuf.put((byte)(0x80 | ((msgLen >>> 8) & 0xFF)));  // pos: 0
        dstBuf.put((byte)(msgLen & 0xFF));                   // pos: 1
        dstBuf.put(SSLHandshake.CLIENT_HELLO.id);            // pos: 2
        dstBuf.put(fragment[offset]);         // major version, pos: 3
        dstBuf.put(fragment[offset + 1]);     // minor version, pos: 4
        dstBuf.put((byte)(v2CSLen >>> 8));                   // pos: 5
        dstBuf.put((byte)(v2CSLen & 0xFF));                  // pos: 6
        dstBuf.put((byte)0x00);           // session_id_length, pos: 7
        dstBuf.put((byte)0x00);                              // pos: 8
        dstBuf.put((byte)0x00);           // challenge_length,  pos: 9
        dstBuf.put((byte)32);                                // pos: 10

        dstBuf.position(0);
        dstBuf.limit(msgLen + 2);

        return dstBuf;
    }

    private static int V3toV2CipherSuite(ByteBuffer dstBuf,
            byte byte1, byte byte2) {
        dstBuf.put((byte)0);
        dstBuf.put(byte1);
        dstBuf.put(byte2);

        if (((byte2 & 0xff) > 0xA) || (V3toV2CipherMap1[byte2] == -1)) {
            return 3;
        }

        dstBuf.put((byte)V3toV2CipherMap1[byte2]);
        dstBuf.put((byte)0);
        dstBuf.put((byte)V3toV2CipherMap3[byte2]);

        return 6;
    }
}