opendaylight/netconf/netconf-netty-util/src/main/java/org/opendaylight/controller/netconf/nettyutil/handler/ssh/client/AsyncSshHandler.java

   1 /*
   2  * Copyright (c) 2014 Cisco Systems, Inc. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8
   9 package org.opendaylight.controller.netconf.nettyutil.handler.ssh.client;
  10
  11 import com.google.common.base.Preconditions;
  12 import io.netty.buffer.ByteBuf;
  13 import io.netty.buffer.Unpooled;
  14 import io.netty.channel.ChannelHandlerContext;
  15 import io.netty.channel.ChannelOutboundHandlerAdapter;
  16 import io.netty.channel.ChannelPromise;
  17 import java.io.IOException;
  18 import java.net.SocketAddress;
  19 import org.apache.sshd.ClientChannel;
  20 import org.apache.sshd.ClientSession;
  21 import org.apache.sshd.SshClient;
  22 import org.apache.sshd.client.future.AuthFuture;
  23 import org.apache.sshd.client.future.ConnectFuture;
  24 import org.apache.sshd.client.future.OpenFuture;
  25 import org.apache.sshd.common.future.CloseFuture;
  26 import org.apache.sshd.common.future.SshFutureListener;
  27 import org.apache.sshd.common.io.IoInputStream;
  28 import org.apache.sshd.common.io.IoReadFuture;
  29 import org.apache.sshd.common.util.Buffer;
  30 import org.opendaylight.controller.netconf.nettyutil.handler.ssh.authentication.AuthenticationHandler;
  31 import org.slf4j.Logger;
  32 import org.slf4j.LoggerFactory;
  33
  34 /**
  35  * Netty SSH handler class. Acts as interface between Netty and SSH library.
  36  */
  37 public class AsyncSshHandler extends ChannelOutboundHandlerAdapter {
  38
  39     private static final Logger logger = LoggerFactory.getLogger(AsyncSshHandler.class);
  40     public static final String SUBSYSTEM = "netconf";
  41
  42     public static final SshClient DEFAULT_CLIENT = SshClient.setUpDefaultClient();
  43
  44     public static final int SSH_DEFAULT_NIO_WORKERS = 8;
  45
  46     static {
  47         // TODO make configurable, or somehow reuse netty threadpool
  48         DEFAULT_CLIENT.setNioWorkers(SSH_DEFAULT_NIO_WORKERS);
  49         DEFAULT_CLIENT.start();
  50     }
  51
  52     private final AuthenticationHandler authenticationHandler;
  53     private final SshClient sshClient;
  54
  55     private SshReadAsyncListener sshReadAsyncListener;
  56     private ClientChannel channel;
  57     private ClientSession session;
  58     private ChannelPromise connectPromise;
  59
  60     public static AsyncSshHandler createForNetconfSubsystem(final AuthenticationHandler authenticationHandler) throws IOException {
  61         return new AsyncSshHandler(authenticationHandler, DEFAULT_CLIENT);
  62     }
  63
  64     /**
  65      *
  66      * @param authenticationHandler
  67      * @param sshClient started SshClient
  68      * @throws IOException
  69      */
  70     public AsyncSshHandler(final AuthenticationHandler authenticationHandler, final SshClient sshClient) throws IOException {
  71         this.authenticationHandler = Preconditions.checkNotNull(authenticationHandler);
  72         this.sshClient = Preconditions.checkNotNull(sshClient);
  73         // Start just in case
  74         sshClient.start();
  75     }
  76
  77     private void startSsh(final ChannelHandlerContext ctx, final SocketAddress address) {
  78         logger.debug("Starting SSH to {} on channel: {}", address, ctx.channel());
  79
  80         final ConnectFuture sshConnectionFuture = sshClient.connect(authenticationHandler.getUsername(), address);
  81         sshConnectionFuture.addListener(new SshFutureListener<ConnectFuture>() {
  82             @Override
  83             public void operationComplete(final ConnectFuture future) {
  84                 if (future.isConnected()) {
  85                     handleSshSessionCreated(future, ctx);
  86                 } else {
  87                     handleSshSetupFailure(ctx, future.getException());
  88                 }
  89             }
  90         });
  91     }
  92
  93     private synchronized void handleSshSessionCreated(final ConnectFuture future, final ChannelHandlerContext ctx) {
  94         try {
  95             logger.trace("SSH session created on channel: {}", ctx.channel());
  96
  97             session = future.getSession();
  98             final AuthFuture authenticateFuture = authenticationHandler.authenticate(session);
  99             authenticateFuture.addListener(new SshFutureListener<AuthFuture>() {
 100                 @Override
 101                 public void operationComplete(final AuthFuture future) {
 102                     if (future.isSuccess()) {
 103                         handleSshAuthenticated(session, ctx);
 104                     } else {
 105                         handleSshSetupFailure(ctx, future.getException());
 106                     }
 107                 }
 108             });
 109         } catch (final IOException e) {
 110             handleSshSetupFailure(ctx, e);
 111         }
 112     }
 113
 114     private synchronized void handleSshAuthenticated(final ClientSession session, final ChannelHandlerContext ctx) {
 115         try {
 116             logger.debug("SSH session authenticated on channel: {}, server version: {}", ctx.channel(), session.getServerVersion());
 117
 118             channel = session.createSubsystemChannel(SUBSYSTEM);
 119             channel.setStreaming(ClientChannel.Streaming.Async);
 120             channel.open().addListener(new SshFutureListener<OpenFuture>() {
 121                 @Override
 122                 public void operationComplete(final OpenFuture future) {
 123                     if(future.isOpened()) {
 124                         handleSshChanelOpened(ctx);
 125                     } else {
 126                         handleSshSetupFailure(ctx, future.getException());
 127                     }
 128                 }
 129             });
 130
 131
 132         } catch (final IOException e) {
 133             handleSshSetupFailure(ctx, e);
 134         }
 135     }
 136
 137     private synchronized void handleSshChanelOpened(final ChannelHandlerContext ctx) {
 138         logger.trace("SSH subsystem channel opened successfully on channel: {}", ctx.channel());
 139
 140         connectPromise.setSuccess();
 141         connectPromise = null;
 142         ctx.fireChannelActive();
 143
 144         final IoInputStream asyncOut = channel.getAsyncOut();
 145         sshReadAsyncListener = new SshReadAsyncListener(ctx, asyncOut);
 146     }
 147
 148     private synchronized void handleSshSetupFailure(final ChannelHandlerContext ctx, final Throwable e) {
 149         logger.warn("Unable to setup SSH connection on channel: {}", ctx.channel(), e);
 150         connectPromise.setFailure(e);
 151         connectPromise = null;
 152         throw new IllegalStateException("Unable to setup SSH connection on channel: " + ctx.channel(), e);
 153     }
 154
 155     @Override
 156     public synchronized void write(final ChannelHandlerContext ctx, final Object msg, final ChannelPromise promise) {
 157         try {
 158             if(channel.getAsyncIn().isClosed() || channel.getAsyncIn().isClosing()) {
 159                 handleSshSessionClosed(ctx);
 160             } else {
 161                 channel.getAsyncIn().write(toBuffer(msg));
 162                 ((ByteBuf) msg).release();
 163             }
 164         } catch (final Exception e) {
 165             logger.warn("Exception while writing to SSH remote on channel {}", ctx.channel(), e);
 166             throw new IllegalStateException("Exception while writing to SSH remote on channel " + ctx.channel(),e);
 167         }
 168     }
 169
 170     private static void handleSshSessionClosed(final ChannelHandlerContext ctx) {
 171         logger.debug("SSH session closed on channel: {}", ctx.channel());
 172         ctx.fireChannelInactive();
 173     }
 174
 175     private Buffer toBuffer(final Object msg) {
 176         // TODO Buffer vs ByteBuf translate, Can we handle that better ?
 177         Preconditions.checkState(msg instanceof ByteBuf);
 178         final ByteBuf byteBuf = (ByteBuf) msg;
 179         final byte[] temp = new byte[byteBuf.readableBytes()];
 180         byteBuf.readBytes(temp, 0, byteBuf.readableBytes());
 181         return new Buffer(temp);
 182     }
 183
 184     @Override
 185     public synchronized void connect(final ChannelHandlerContext ctx, final SocketAddress remoteAddress, final SocketAddress localAddress, final ChannelPromise promise) throws Exception {
 186         this.connectPromise = promise;
 187         startSsh(ctx, remoteAddress);
 188     }
 189
 190     @Override
 191     public void close(final ChannelHandlerContext ctx, final ChannelPromise promise) throws Exception {
 192         disconnect(ctx, promise);
 193     }
 194
 195     @Override
 196     public synchronized void disconnect(final ChannelHandlerContext ctx, final ChannelPromise promise) throws Exception {
 197         if(sshReadAsyncListener != null) {
 198             sshReadAsyncListener.close();
 199         }
 200
 201         session.close(false).addListener(new SshFutureListener<CloseFuture>() {
 202             @Override
 203             public void operationComplete(final CloseFuture future) {
 204                 if(future.isClosed() == false) {
 205                     session.close(true);
 206                 }
 207                 session = null;
 208             }
 209         });
 210
 211         channel = null;
 212     }
 213
 214     /**
 215      * Listener over async input stream from SSH session.
 216      * This listeners schedules reads in a loop until the session is closed or read fails.
 217      */
 218     private static class SshReadAsyncListener implements SshFutureListener<IoReadFuture>, AutoCloseable {
 219         private static final int BUFFER_SIZE = 8192;
 220
 221         private final ChannelHandlerContext ctx;
 222
 223         private IoInputStream asyncOut;
 224         private Buffer buf;
 225         private IoReadFuture currentReadFuture;
 226
 227         public SshReadAsyncListener(final ChannelHandlerContext ctx, final IoInputStream asyncOut) {
 228             this.ctx = ctx;
 229             this.asyncOut = asyncOut;
 230             buf = new Buffer(BUFFER_SIZE);
 231             asyncOut.read(buf).addListener(this);
 232         }
 233
 234         @Override
 235         public synchronized void operationComplete(final IoReadFuture future) {
 236             if(future.getException() != null) {
 237
 238                 if(asyncOut.isClosed() || asyncOut.isClosing()) {
 239                     // We are closing
 240                     handleSshSessionClosed(ctx);
 241                 } else {
 242                     logger.warn("Exception while reading from SSH remote on channel {}", ctx.channel(), future.getException());
 243                     throw new IllegalStateException("Exception while reading from SSH remote on channel " + ctx.channel(), future.getException());
 244                 }
 245             }
 246
 247             if (future.getRead() > 0) {
 248                 ctx.fireChannelRead(Unpooled.wrappedBuffer(buf.array(), 0, future.getRead()));
 249
 250                 // Schedule next read
 251                 buf = new Buffer(BUFFER_SIZE);
 252                 currentReadFuture = asyncOut.read(buf);
 253                 currentReadFuture.addListener(this);
 254             }
 255         }
 256
 257         @Override
 258         public synchronized void close() throws Exception {
 259             // Remove self as listener on close to prevent reading from closed input
 260             if(currentReadFuture != null) {
 261                 currentReadFuture.removeListener(this);
 262             }
 263
 264             asyncOut = null;
 265         }
 266     }
 267 }