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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).

 *

 * 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.

 *

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package jdk.internal.net.rdma;

import java.io.FileDescriptor;

import java.io.IOException;

import java.net.InetAddress;

import java.net.InetSocketAddress;

import java.net.ProtocolFamily;

import java.net.ServerSocket;

import java.net.SocketAddress;

import java.net.SocketOption;

import java.net.StandardSocketOptions;

import java.net.StandardProtocolFamily;

import java.nio.channels.AlreadyBoundException;

import java.nio.channels.AsynchronousCloseException;

import java.nio.channels.ClosedChannelException;

import java.nio.channels.NotYetBoundException;

import java.nio.channels.SelectionKey;

import java.nio.channels.ServerSocketChannel;

import java.nio.channels.SocketChannel;

import java.nio.channels.UnsupportedAddressTypeException;

import java.nio.channels.spi.SelectorProvider;

import java.util.Collections;

import java.util.HashSet;

import java.util.Objects;

import java.util.Set;

import java.util.concurrent.locks.ReentrantLock;

import sun.nio.ch.IOStatus;

import sun.nio.ch.IOUtil;

import sun.nio.ch.NativeThread;

import sun.nio.ch.Net;

import sun.nio.ch.SelChImpl;

import sun.nio.ch.SelectionKeyImpl;

import sun.net.ext.RdmaSocketOptions;

import static java.net.StandardProtocolFamily.INET;

import static java.net.StandardProtocolFamily.INET6;

public class RdmaServerSocketChannelImpl

    extends ServerSocketChannel

    implements SelChImpl

{

    //The protocol family of the socket

    private final ProtocolFamily family;

    private static RdmaSocketDispatcher nd;

    private final FileDescriptor fd;

    private final int fdVal;

    private final ReentrantLock acceptLock = new ReentrantLock();

    private final Object stateLock = new Object();

    private static final int ST_INUSE = 0;

    private static final int ST_CLOSING = 1;

    private static final int ST_KILLPENDING = 2;

    private static final int ST_KILLED = 3;

    private int state;

    private long thread;

    private InetSocketAddress localAddress;

    private boolean isReuseAddress;

    private ServerSocket socket;

    private static final UnsupportedOperationException unsupported;

    private static final SelectorProvider checkSupported(SelectorProvider sp) {

        if (unsupported != null)

            throw new UnsupportedOperationException(unsupported.getMessage(), unsupported);

        else

            return sp;

    }

    RdmaServerSocketChannelImpl(SelectorProvider sp, ProtocolFamily family)

            throws IOException {

        super(checkSupported(sp));

        Objects.requireNonNull(family, "'family' is null");

        if (!(family == INET || family == INET6)) {

            throw new UnsupportedOperationException(

                    "Protocol family not supported");

        }

        if (family == INET6) {

            if (!Net.isIPv6Available()) {

                throw new UnsupportedOperationException(

                        "IPv6 not available");

            }

        }

        this.family = family;

        this.fd = RdmaNet.serverSocket(family, true);

        this.fdVal = IOUtil.fdVal(fd);

    }

    private void ensureOpen() throws ClosedChannelException {

        if (!isOpen())

            throw new ClosedChannelException();

    }

    @Override

    public ServerSocket socket() {

        synchronized (stateLock) {

            if (socket == null)

                socket = RdmaServerSocketAdaptor.create(this);

            return socket;

        }

    }

    @Override

    public SocketAddress getLocalAddress() throws IOException {

        synchronized (stateLock) {

            ensureOpen();

            return (localAddress == null)

                    ? null

                    : Net.getRevealedLocalAddress(localAddress);

        }

    }

    @Override

    public <T> ServerSocketChannel setOption(SocketOption<T> name, T value)

            throws IOException

    {

        Objects.requireNonNull(name);

        if (!supportedOptions().contains(name))

            throw new UnsupportedOperationException("'" + name

                    + "' not supported");

        synchronized (stateLock) {

            ensureOpen();

            if (isBound() && (name == StandardSocketOptions.SO_REUSEADDR))

                throw new UnsupportedOperationException(

                        "RDMA server socket channel cannot set the socket option "

                        + name.toString() + " after bind.");

            RdmaNet.setSocketOption(fd, RdmaNet.UNSPEC, name, value);

            return this;

        }

    }

    @Override

    @SuppressWarnings("unchecked")

    public <T> T getOption(SocketOption<T> name)

            throws IOException

    {

        Objects.requireNonNull(name);

        if (!supportedOptions().contains(name))

            throw new UnsupportedOperationException("'" + name

                    + "' not supported");

        synchronized (stateLock) {

            ensureOpen();

            return (T) RdmaNet.getSocketOption(fd, RdmaNet.UNSPEC, name);

        }

    }

    private static class DefaultOptionsHolder {

        static final Set<SocketOption<?>> defaultOptions = defaultOptions();

        private static Set<SocketOption<?>> defaultOptions() {

            HashSet<SocketOption<?>> set = new HashSet<>(2);

            set.add(StandardSocketOptions.SO_RCVBUF);

            set.add(StandardSocketOptions.SO_REUSEADDR);

            if (RdmaNet.isRdmaAvailable()) {

                RdmaSocketOptions rdmaOptions =

                        RdmaSocketOptions.getInstance();

                set.addAll(rdmaOptions.options());

            }

            return Collections.unmodifiableSet(set);

        }

    }

    public final Set<SocketOption<?>> supportedOptions() {

        return DefaultOptionsHolder.defaultOptions;

    }

    private final InetSocketAddress anyLocalAddress() throws IOException {

        if (family == INET)

            return new InetSocketAddress(InetAddress.getByName("0.0.0.0"), 0);

        else if (family == INET6)

            return new InetSocketAddress(InetAddress.getByName("::"), 0);

        else

            throw new UnsupportedAddressTypeException();

    }

    @Override

    public ServerSocketChannel bind(SocketAddress local, int backlog)

            throws IOException {

        synchronized (stateLock) {

            ensureOpen();

            if (localAddress != null)

                throw new AlreadyBoundException();

            InetSocketAddress isa = (local == null)

                                    ? anyLocalAddress()

                                    : RdmaNet.checkAddress(local, family);

            SecurityManager sm = System.getSecurityManager();

            if (sm != null)

                sm.checkListen(isa.getPort());

            RdmaNet.bind(family, fd, isa.getAddress(), isa.getPort());

            RdmaNet.listen(fd, backlog < 1 ? 50 : backlog);

            localAddress = RdmaNet.localAddress(fd);

        }

        return this;

    }

    private void begin(boolean blocking) throws ClosedChannelException {

        if (blocking)

            begin();

        synchronized (stateLock) {

            ensureOpen();

            if (localAddress == null)

                throw new NotYetBoundException();

            if (blocking)

                thread = NativeThread.current();

        }

    }

    private void end(boolean blocking, boolean completed)

            throws AsynchronousCloseException {

        if (blocking) {

            synchronized (stateLock) {

                thread = 0;

                if (state == ST_CLOSING) {

                    stateLock.notifyAll();

                }

            }

            end(completed);

        }

    }

    @Override

    public SocketChannel accept() throws IOException {

        acceptLock.lock();

        try {

            int n = 0;

            FileDescriptor newfd = new FileDescriptor();

            InetSocketAddress[] isaa = new InetSocketAddress[1];

            boolean blocking = isBlocking();

            try {

                begin(blocking);

                do {

                    if (blocking) {

                        do {

                            n  = checkAccept(this.fd);

                        } while ((n == 0 || n == IOStatus.INTERRUPTED)

                                && isOpen());

                    }

                    n = accept(this.fd, newfd, isaa);

                } while (n == IOStatus.INTERRUPTED && isOpen());

            } finally {

                end(blocking, n > 0);

                assert IOStatus.check(n);

            }

            if (n < 1)

                return null;

            // newly accepted socket is initially in blocking mode

            RdmaNet.configureBlocking(newfd, true);

            InetSocketAddress isa = isaa[0];

            SocketChannel sc = new RdmaSocketChannelImpl(provider(),

                    newfd, isa);

            // check permitted to accept connections from the remote address

            SecurityManager sm = System.getSecurityManager();

            if (sm != null) {

                try {

                    sm.checkAccept(isa.getAddress().getHostAddress(),

                            isa.getPort());

                } catch (SecurityException x) {

                    sc.close();

                    throw x;

                }

            }

            return sc;

        } finally {

            acceptLock.unlock();

        }

    }

    @Override

    protected void implConfigureBlocking(boolean block) throws IOException {

        acceptLock.lock();

        try {

            synchronized (stateLock) {

                ensureOpen();

                RdmaNet.configureBlocking(fd, block);

            }

        } finally {

            acceptLock.unlock();

        }

    }

    @Override

    protected void implCloseSelectableChannel() throws IOException {

        assert !isOpen();

        boolean interrupted = false;

        boolean blocking;

        // set state to ST_CLOSING

        synchronized (stateLock) {

            assert state < ST_CLOSING;

            state = ST_CLOSING;

            blocking = isBlocking();

        }

        // wait for any outstanding accept to complete

        if (blocking) {

            synchronized (stateLock) {

                assert state == ST_CLOSING;

                long th = thread;

                if (th != 0) {

                    nd.preClose(fd);

                    NativeThread.signal(th);

                    // wait for accept operation to end

                    while (thread != 0) {

                        try {

                            stateLock.wait();

                        } catch (InterruptedException e) {

                            interrupted = true;

                        }

                    }

                }

            }

        } else {

            // non-blocking mode: wait for accept to complete

            acceptLock.lock();

            acceptLock.unlock();

        }

        // set state to ST_KILLPENDING

        synchronized (stateLock) {

            assert state == ST_CLOSING;

            state = ST_KILLPENDING;

        }

        // close socket if not registered with Selector

        if (!isRegistered())

            kill();

        // restore interrupt status

        if (interrupted)

            Thread.currentThread().interrupt();

    }

    @Override

    public void kill() throws IOException {

        synchronized (stateLock) {

            if (state == ST_KILLPENDING) {

                state = ST_KILLED;

                nd.close(fd);

            }

        }

    }

    boolean isBound() {

        synchronized (stateLock) {

            return localAddress != null;

        }

    }

    InetSocketAddress localAddress() {

        synchronized (stateLock) {

            return localAddress;

        }

    }

    /**

     * Poll this channel's socket for a new connection up to the given timeout.

     * @return {@code true} if there is a connection to accept

     */

    boolean pollAccept(long timeout) throws IOException {

        assert Thread.holdsLock(blockingLock()) && isBlocking();

        acceptLock.lock();

        try {

            boolean polled = false;

            try {

                begin(true);

                int events = RdmaNet.poll(fd, Net.POLLIN, timeout);

                polled = (events != 0);

            } finally {

                end(true, polled);

            }

            return polled;

        } finally {

            acceptLock.unlock();

        }

    }

    public boolean translateReadyOps(int ops, int initialOps,

            SelectionKeyImpl ski) {

        int intOps = ski.nioInterestOps();

        int oldOps = ski.nioReadyOps();

        int newOps = initialOps;

        if ((ops & Net.POLLNVAL) != 0) {

            return false;

        }

        if ((ops & (Net.POLLERR | Net.POLLHUP)) != 0) {

            newOps = intOps;

            ski.nioReadyOps(newOps);

            return (newOps & ~oldOps) != 0;

        }

        if (((ops & Net.POLLIN) != 0) &&

            ((intOps & SelectionKey.OP_ACCEPT) != 0))

                newOps |= SelectionKey.OP_ACCEPT;

        ski.nioReadyOps(newOps);

        return (newOps & ~oldOps) != 0;

    }

    public boolean translateAndUpdateReadyOps(int ops, SelectionKeyImpl ski) {

        return translateReadyOps(ops, ski.nioReadyOps(), ski);

    }

    public boolean translateAndSetReadyOps(int ops, SelectionKeyImpl ski) {

        return translateReadyOps(ops, 0, ski);

    }

    public int translateInterestOps(int ops) {

        int newOps = 0;

        if ((ops & SelectionKey.OP_ACCEPT) != 0)

            newOps |= Net.POLLIN;

        return newOps;

    }

    public FileDescriptor getFD() {

        return fd;

    }

    public int getFDVal() {

        return fdVal;

    }

    public String toString() {

        StringBuilder sb = new StringBuilder();

        sb.append(this.getClass().getName());

        sb.append('[');

        if (!isOpen()) {

            sb.append("closed");

        } else {

            synchronized (stateLock) {

                InetSocketAddress addr = localAddress;

                if (addr == null) {

                    sb.append("unbound");

                } else {

                    sb.append(Net.getRevealedLocalAddressAsString(addr));

                }

            }

        }

        sb.append(']');

        return sb.toString();

    }

    private int accept(FileDescriptor ssfd, FileDescriptor newfd,

            InetSocketAddress[] isaa) throws IOException {

        return accept0(ssfd, newfd, isaa);

    }

    // -- Native methods --

    private static native int checkAccept(FileDescriptor fd)

            throws IOException;

    private native int accept0(FileDescriptor ssfd, FileDescriptor newfd,

            InetSocketAddress[] isaa) throws IOException;

    private static native void initIDs()throws UnsupportedOperationException;

    static {

        IOUtil.load();

        System.loadLibrary("extnet");

        UnsupportedOperationException uoe = null;

        try {

            initIDs();

        } catch (UnsupportedOperationException e) {

            uoe = e;

        }

        unsupported = uoe;

        nd = new RdmaSocketDispatcher();

    }

}