/*
 * Copyright (c) 2005, 2011, 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
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package sun.net.httpserver;

import java.net.*;
import java.nio.*;
import java.io.*;
import java.nio.channels.*;
import java.util.concurrent.locks.*;
import javax.net.ssl.*;
import javax.net.ssl.SSLEngineResult.*;
import com.sun.net.httpserver.*;

given a non-blocking SocketChannel, it produces
(blocking) streams which encrypt/decrypt the SSL content
and handle the SSL handshaking automatically.
/**
 * given a non-blocking SocketChannel, it produces
 * (blocking) streams which encrypt/decrypt the SSL content
 * and handle the SSL handshaking automatically.
 */

class SSLStreams {

    SSLContext sslctx;
    SocketChannel chan;
    TimeSource time;
    ServerImpl server;
    SSLEngine engine;
    EngineWrapper wrapper;
    OutputStream os;
    InputStream is;

    /* held by thread doing the hand-shake on this connection */
    Lock handshaking = new ReentrantLock();

    SSLStreams (ServerImpl server, SSLContext sslctx, SocketChannel chan) throws IOException {
        this.server = server;
        this.time= (TimeSource)server;
        this.sslctx= sslctx;
        this.chan= chan;
        InetSocketAddress addr =
                (InetSocketAddress)chan.socket().getRemoteSocketAddress();
        engine = sslctx.createSSLEngine (addr.getHostName(), addr.getPort());
        engine.setUseClientMode (false);
        HttpsConfigurator cfg = server.getHttpsConfigurator();
        configureEngine (cfg, addr);
        wrapper = new EngineWrapper (chan, engine);
    }

    private void configureEngine(HttpsConfigurator cfg, InetSocketAddress addr){
        if (cfg != null) {
            Parameters params = new Parameters (cfg, addr);
//BEGIN_TIGER_EXCLUDE
            cfg.configure (params);
            SSLParameters sslParams = params.getSSLParameters();
            if (sslParams != null) {
                engine.setSSLParameters (sslParams);
            } else
//END_TIGER_EXCLUDE
            {
                /* tiger compatibility */
                if (params.getCipherSuites() != null) {
                    try {
                        engine.setEnabledCipherSuites (
                            params.getCipherSuites()
                        );
                    } catch (IllegalArgumentException e) { /* LOG */}
                }
                engine.setNeedClientAuth (params.getNeedClientAuth());
                engine.setWantClientAuth (params.getWantClientAuth());
                if (params.getProtocols() != null) {
                    try {
                        engine.setEnabledProtocols (
                            params.getProtocols()
                        );
                    } catch (IllegalArgumentException e) { /* LOG */}
                }
            }
        }
    }

    class Parameters extends HttpsParameters {
        InetSocketAddress addr;
        HttpsConfigurator cfg;

        Parameters (HttpsConfigurator cfg, InetSocketAddress addr) {
            this.addr = addr;
            this.cfg = cfg;
        }
        public InetSocketAddress getClientAddress () {
            return addr;
        }
        public HttpsConfigurator getHttpsConfigurator() {
            return cfg;
        }
//BEGIN_TIGER_EXCLUDE
        SSLParameters params;
        public void setSSLParameters (SSLParameters p) {
            params = p;
        }
        SSLParameters getSSLParameters () {
            return params;
        }
//END_TIGER_EXCLUDE
    }

    
cleanup resources allocated inside this object
/**
     * cleanup resources allocated inside this object
     */
    void close () throws IOException {
        wrapper.close();
    }

    
return the SSL InputStream
/**
     * return the SSL InputStream
     */
    InputStream getInputStream () throws IOException {
        if (is == null) {
            is = new InputStream();
        }
        return is;
    }

    
return the SSL OutputStream
/**
     * return the SSL OutputStream
     */
    OutputStream getOutputStream () throws IOException {
        if (os == null) {
            os = new OutputStream();
        }
        return os;
    }

    SSLEngine getSSLEngine () {
        return engine;
    }

    
request the engine to repeat the handshake on this session
the handshake must be driven by reads/writes on the streams
Normally, not necessary to call this.
/**
     * request the engine to repeat the handshake on this session
     * the handshake must be driven by reads/writes on the streams
     * Normally, not necessary to call this.
     */
    void beginHandshake() throws SSLException {
        engine.beginHandshake();
    }

    class WrapperResult {
        SSLEngineResult result;

        /* if passed in buffer was not big enough then the
         * a reallocated buffer is returned here
         */
        ByteBuffer buf;
    }

    int app_buf_size;
    int packet_buf_size;

    enum BufType {
        PACKET, APPLICATION
    };

    private ByteBuffer allocate (BufType type) {
        return allocate (type, -1);
    }

    private ByteBuffer allocate (BufType type, int len) {
        assert engine != null;
        synchronized (this) {
            int size;
            if (type == BufType.PACKET) {
                if (packet_buf_size == 0) {
                    SSLSession sess = engine.getSession();
                    packet_buf_size = sess.getPacketBufferSize();
                }
                if (len > packet_buf_size) {
                    packet_buf_size = len;
                }
                size = packet_buf_size;
            } else {
                if (app_buf_size == 0) {
                    SSLSession sess = engine.getSession();
                    app_buf_size = sess.getApplicationBufferSize();
                }
                if (len > app_buf_size) {
                    app_buf_size = len;
                }
                size = app_buf_size;
            }
            return ByteBuffer.allocate (size);
        }
    }

    /* reallocates the buffer by :-
     * 1. creating a new buffer double the size of the old one
     * 2. putting the contents of the old buffer into the new one
     * 3. set xx_buf_size to the new size if it was smaller than new size
     *
     * flip is set to true if the old buffer needs to be flipped
     * before it is copied.
     */
    private ByteBuffer realloc (ByteBuffer b, boolean flip, BufType type) {
        synchronized (this) {
            int nsize = 2 * b.capacity();
            ByteBuffer n = allocate (type, nsize);
            if (flip) {
                b.flip();
            }
            n.put(b);
            b = n;
        }
        return b;
    }
    
This is a thin wrapper over SSLEngine and the SocketChannel,
which guarantees the ordering of wraps/unwraps with respect to the underlying
channel read/writes. It handles the UNDER/OVERFLOW status codes
It does not handle the handshaking status codes, or the CLOSED status code
though once the engine is closed, any attempt to read/write to it
will get an exception.  The overall result is returned.
It functions synchronously/blocking
/**
     * This is a thin wrapper over SSLEngine and the SocketChannel,
     * which guarantees the ordering of wraps/unwraps with respect to the underlying
     * channel read/writes. It handles the UNDER/OVERFLOW status codes
     * It does not handle the handshaking status codes, or the CLOSED status code
     * though once the engine is closed, any attempt to read/write to it
     * will get an exception.  The overall result is returned.
     * It functions synchronously/blocking
     */
    class EngineWrapper {

        SocketChannel chan;
        SSLEngine engine;
        Object wrapLock, unwrapLock;
        ByteBuffer unwrap_src, wrap_dst;
        boolean closed = false;
        int u_remaining; // the number of bytes left in unwrap_src after an unwrap()

        EngineWrapper (SocketChannel chan, SSLEngine engine) throws IOException {
            this.chan = chan;
            this.engine = engine;
            wrapLock = new Object();
            unwrapLock = new Object();
            unwrap_src = allocate(BufType.PACKET);
            wrap_dst = allocate(BufType.PACKET);
        }

        void close () throws IOException {
        }

        /* try to wrap and send the data in src. Handles OVERFLOW.
         * Might block if there is an outbound blockage or if another
         * thread is calling wrap(). Also, might not send any data
         * if an unwrap is needed.
         */
        WrapperResult wrapAndSend(ByteBuffer src) throws IOException {
            return wrapAndSendX(src, false);
        }

        WrapperResult wrapAndSendX(ByteBuffer src, boolean ignoreClose) throws IOException {
            if (closed && !ignoreClose) {
                throw new IOException ("Engine is closed");
            }
            Status status;
            WrapperResult r = new WrapperResult();
            synchronized (wrapLock) {
                wrap_dst.clear();
                do {
                    r.result = engine.wrap (src, wrap_dst);
                    status = r.result.getStatus();
                    if (status == Status.BUFFER_OVERFLOW) {
                        wrap_dst = realloc (wrap_dst, true, BufType.PACKET);
                    }
                } while (status == Status.BUFFER_OVERFLOW);
                if (status == Status.CLOSED && !ignoreClose) {
                    closed = true;
                    return r;
                }
                if (r.result.bytesProduced() > 0) {
                    wrap_dst.flip();
                    int l = wrap_dst.remaining();
                    assert l == r.result.bytesProduced();
                    while (l>0) {
                        l -= chan.write (wrap_dst);
                    }
                }
            }
            return r;
        }

        /* block until a complete message is available and return it
         * in dst, together with the Result. dst may have been re-allocated
         * so caller should check the returned value in Result
         * If handshaking is in progress then, possibly no data is returned
         */
        WrapperResult recvAndUnwrap(ByteBuffer dst) throws IOException {
            Status status = Status.OK;
            WrapperResult r = new WrapperResult();
            r.buf = dst;
            if (closed) {
                throw new IOException ("Engine is closed");
            }
            boolean needData;
            if (u_remaining > 0) {
                unwrap_src.compact();
                unwrap_src.flip();
                needData = false;
            } else {
                unwrap_src.clear();
                needData = true;
            }
            synchronized (unwrapLock) {
                int x;
                do {
                    if (needData) {
                        do {
                        x = chan.read (unwrap_src);
                        } while (x == 0);
                        if (x == -1) {
                            throw new IOException ("connection closed for reading");
                        }
                        unwrap_src.flip();
                    }
                    r.result = engine.unwrap (unwrap_src, r.buf);
                    status = r.result.getStatus();
                    if (status == Status.BUFFER_UNDERFLOW) {
                        if (unwrap_src.limit() == unwrap_src.capacity()) {
                            /* buffer not big enough */
                            unwrap_src = realloc (
                                unwrap_src, false, BufType.PACKET
                            );
                        } else {
                            /* Buffer not full, just need to read more
                             * data off the channel. Reset pointers
                             * for reading off SocketChannel
                             */
                            unwrap_src.position (unwrap_src.limit());
                            unwrap_src.limit (unwrap_src.capacity());
                        }
                        needData = true;
                    } else if (status == Status.BUFFER_OVERFLOW) {
                        r.buf = realloc (r.buf, true, BufType.APPLICATION);
                        needData = false;
                    } else if (status == Status.CLOSED) {
                        closed = true;
                        r.buf.flip();
                        return r;
                    }
                } while (status != Status.OK);
            }
            u_remaining = unwrap_src.remaining();
            return r;
        }
    }

    
send the data in the given ByteBuffer. If a handshake is needed
then this is handled within this method. When this call returns,
all of the given user data has been sent and any handshake has been
completed. Caller should check if engine has been closed.
/**
     * send the data in the given ByteBuffer. If a handshake is needed
     * then this is handled within this method. When this call returns,
     * all of the given user data has been sent and any handshake has been
     * completed. Caller should check if engine has been closed.
     */
    public WrapperResult sendData (ByteBuffer src) throws IOException {
        WrapperResult r=null;
        while (src.remaining() > 0) {
            r = wrapper.wrapAndSend(src);
            Status status = r.result.getStatus();
            if (status == Status.CLOSED) {
                doClosure ();
                return r;
            }
            HandshakeStatus hs_status = r.result.getHandshakeStatus();
            if (hs_status != HandshakeStatus.FINISHED &&
                hs_status != HandshakeStatus.NOT_HANDSHAKING)
            {
                doHandshake(hs_status);
            }
        }
        return r;
    }

    
read data thru the engine into the given ByteBuffer. If the
given buffer was not large enough, a new one is allocated
and returned. This call handles handshaking automatically.
Caller should check if engine has been closed.
/**
     * read data thru the engine into the given ByteBuffer. If the
     * given buffer was not large enough, a new one is allocated
     * and returned. This call handles handshaking automatically.
     * Caller should check if engine has been closed.
     */
    public WrapperResult recvData (ByteBuffer dst) throws IOException {
        /* we wait until some user data arrives */
        WrapperResult r = null;
        assert dst.position() == 0;
        while (dst.position() == 0) {
            r = wrapper.recvAndUnwrap (dst);
            dst = (r.buf != dst) ? r.buf: dst;
            Status status = r.result.getStatus();
            if (status == Status.CLOSED) {
                doClosure ();
                return r;
            }

            HandshakeStatus hs_status = r.result.getHandshakeStatus();
            if (hs_status != HandshakeStatus.FINISHED &&
                hs_status != HandshakeStatus.NOT_HANDSHAKING)
            {
                doHandshake (hs_status);
            }
        }
        dst.flip();
        return r;
    }

    /* we've received a close notify. Need to call wrap to send
     * the response
     */
    void doClosure () throws IOException {
        try {
            handshaking.lock();
            ByteBuffer tmp = allocate(BufType.APPLICATION);
            WrapperResult r;
            do {
                tmp.clear();
                tmp.flip ();
                r = wrapper.wrapAndSendX (tmp, true);
            } while (r.result.getStatus() != Status.CLOSED);
        } finally {
            handshaking.unlock();
        }
    }

    /* do the (complete) handshake after acquiring the handshake lock.
     * If two threads call this at the same time, then we depend
     * on the wrapper methods being idempotent. eg. if wrapAndSend()
     * is called with no data to send then there must be no problem
     */
    @SuppressWarnings("fallthrough")
    void doHandshake (HandshakeStatus hs_status) throws IOException {
        try {
            handshaking.lock();
            ByteBuffer tmp = allocate(BufType.APPLICATION);
            while (hs_status != HandshakeStatus.FINISHED &&
                   hs_status != HandshakeStatus.NOT_HANDSHAKING)
            {
                WrapperResult r = null;
                switch (hs_status) {
                    case NEED_TASK:
                        Runnable task;
                        while ((task = engine.getDelegatedTask()) != null) {
                            /* run in current thread, because we are already
                             * running an external Executor
                             */
                            task.run();
                        }
                        /* fall thru - call wrap again */
                    case NEED_WRAP:
                        tmp.clear();
                        tmp.flip();
                        r = wrapper.wrapAndSend(tmp);
                        break;

                    case NEED_UNWRAP:
                        tmp.clear();
                        r = wrapper.recvAndUnwrap (tmp);
                        if (r.buf != tmp) {
                            tmp = r.buf;
                        }
                        assert tmp.position() == 0;
                        break;
                }
                hs_status = r.result.getHandshakeStatus();
            }
        } finally {
            handshaking.unlock();
        }
    }

    
represents an SSL input stream. Multiple https requests can
be sent over one stream. closing this stream causes an SSL close
input.
/**
     * represents an SSL input stream. Multiple https requests can
     * be sent over one stream. closing this stream causes an SSL close
     * input.
     */
    class InputStream extends java.io.InputStream {

        ByteBuffer bbuf;
        boolean closed = false;

        /* this stream eof */
        boolean eof = false;

        boolean needData = true;

        InputStream () {
            bbuf = allocate (BufType.APPLICATION);
        }

        public int read (byte[] buf, int off, int len) throws IOException {
            if (closed) {
                throw new IOException ("SSL stream is closed");
            }
            if (eof) {
                return 0;
            }
            int available=0;
            if (!needData) {
                available = bbuf.remaining();
                needData = (available==0);
            }
            if (needData) {
                bbuf.clear();
                WrapperResult r = recvData (bbuf);
                bbuf = r.buf== bbuf? bbuf: r.buf;
                if ((available=bbuf.remaining()) == 0) {
                    eof = true;
                    return 0;
                } else {
                    needData = false;
                }
            }
            /* copy as much as possible from buf into users buf */
            if (len > available) {
                len = available;
            }
            bbuf.get (buf, off, len);
            return len;
        }

        public int available () throws IOException {
            return bbuf.remaining();
        }

        public boolean markSupported () {
            return false; /* not possible with SSLEngine */
        }

        public void reset () throws IOException {
            throw new IOException ("mark/reset not supported");
        }

        public long skip (long s) throws IOException {
            int n = (int)s;
            if (closed) {
                throw new IOException ("SSL stream is closed");
            }
            if (eof) {
                return 0;
            }
            int ret = n;
            while (n > 0) {
                if (bbuf.remaining() >= n) {
                    bbuf.position (bbuf.position()+n);
                    return ret;
                } else {
                    n -= bbuf.remaining();
                    bbuf.clear();
                    WrapperResult r = recvData (bbuf);
                    bbuf = r.buf==bbuf? bbuf: r.buf;
                }
            }
            return ret; /* not reached */
        }

        
close the SSL connection. All data must have been consumed
before this is called. Otherwise an exception will be thrown.
[Note. May need to revisit this. not quite the normal close() symantics
/**
         * close the SSL connection. All data must have been consumed
         * before this is called. Otherwise an exception will be thrown.
         * [Note. May need to revisit this. not quite the normal close() symantics
         */
        public void close () throws IOException {
            eof = true;
            engine.closeInbound ();
        }

        public int read (byte[] buf) throws IOException {
            return read (buf, 0, buf.length);
        }

        byte single[] = new byte [1];

        public int read () throws IOException {
            int n = read (single, 0, 1);
            if (n == 0) {
                return -1;
            } else {
                return single[0] & 0xFF;
            }
        }
    }

    
represents an SSL output stream. plain text data written to this stream
is encrypted by the stream. Multiple HTTPS responses can be sent on
one stream. closing this stream initiates an SSL closure
/**
     * represents an SSL output stream. plain text data written to this stream
     * is encrypted by the stream. Multiple HTTPS responses can be sent on
     * one stream. closing this stream initiates an SSL closure
     */
    class OutputStream extends java.io.OutputStream {
        ByteBuffer buf;
        boolean closed = false;
        byte single[] = new byte[1];

        OutputStream() {
            buf = allocate(BufType.APPLICATION);
        }

        public void write(int b) throws IOException {
            single[0] = (byte)b;
            write (single, 0, 1);
        }

        public void write(byte b[]) throws IOException {
            write (b, 0, b.length);
        }
        public void write(byte b[], int off, int len) throws IOException {
            if (closed) {
                throw new IOException ("output stream is closed");
            }
            while (len > 0) {
                int l = len > buf.capacity() ? buf.capacity() : len;
                buf.clear();
                buf.put (b, off, l);
                len -= l;
                off += l;
                buf.flip();
                WrapperResult r = sendData (buf);
                if (r.result.getStatus() == Status.CLOSED) {
                    closed = true;
                    if (len > 0) {
                        throw new IOException ("output stream is closed");
                    }
                }
            }
        }

        public void flush() throws IOException {
            /* no-op */
        }

        public void close() throws IOException {
            WrapperResult r=null;
            engine.closeOutbound();
            closed = true;
            HandshakeStatus stat = HandshakeStatus.NEED_WRAP;
            buf.clear();
            while (stat == HandshakeStatus.NEED_WRAP) {
                r = wrapper.wrapAndSend (buf);
                stat = r.result.getHandshakeStatus();
            }
            assert r.result.getStatus() == Status.CLOSED;
        }
    }
}