2 * Copyright (c) 2014 Cisco Systems, Inc. and others. All rights reserved.
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
9 package org.opendaylight.controller.netconf.nettyutil.handler.ssh.client;
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.ChannelOutboundHandler;
16 import io.netty.channel.ChannelOutboundHandlerAdapter;
17 import io.netty.channel.ChannelPromise;
18 import java.io.IOException;
19 import java.net.SocketAddress;
20 import org.apache.sshd.ClientChannel;
21 import org.apache.sshd.ClientSession;
22 import org.apache.sshd.SshClient;
23 import org.apache.sshd.client.future.AuthFuture;
24 import org.apache.sshd.client.future.ConnectFuture;
25 import org.apache.sshd.client.future.OpenFuture;
26 import org.apache.sshd.common.future.CloseFuture;
27 import org.apache.sshd.common.future.SshFutureListener;
28 import org.apache.sshd.common.io.IoInputStream;
29 import org.apache.sshd.common.io.IoOutputStream;
30 import org.apache.sshd.common.io.IoReadFuture;
31 import org.apache.sshd.common.io.IoWriteFuture;
32 import org.apache.sshd.common.io.WritePendingException;
33 import org.apache.sshd.common.util.Buffer;
34 import org.opendaylight.controller.netconf.nettyutil.handler.ssh.authentication.AuthenticationHandler;
35 import org.slf4j.Logger;
36 import org.slf4j.LoggerFactory;
39 * Netty SSH handler class. Acts as interface between Netty and SSH library.
41 public class AsyncSshHandler extends ChannelOutboundHandlerAdapter {
43 private static final Logger logger = LoggerFactory.getLogger(AsyncSshHandler.class);
44 public static final String SUBSYSTEM = "netconf";
46 public static final SshClient DEFAULT_CLIENT = SshClient.setUpDefaultClient();
48 public static final int SSH_DEFAULT_NIO_WORKERS = 8;
51 // TODO make configurable, or somehow reuse netty threadpool
52 DEFAULT_CLIENT.setNioWorkers(SSH_DEFAULT_NIO_WORKERS);
53 DEFAULT_CLIENT.start();
56 private final AuthenticationHandler authenticationHandler;
57 private final SshClient sshClient;
59 private SshReadAsyncListener sshReadAsyncListener;
60 private SshWriteAsyncHandler sshWriteAsyncHandler;
62 private ClientChannel channel;
63 private ClientSession session;
64 private ChannelPromise connectPromise;
67 public static AsyncSshHandler createForNetconfSubsystem(final AuthenticationHandler authenticationHandler) throws IOException {
68 return new AsyncSshHandler(authenticationHandler, DEFAULT_CLIENT);
73 * @param authenticationHandler
74 * @param sshClient started SshClient
77 public AsyncSshHandler(final AuthenticationHandler authenticationHandler, final SshClient sshClient) throws IOException {
78 this.authenticationHandler = Preconditions.checkNotNull(authenticationHandler);
79 this.sshClient = Preconditions.checkNotNull(sshClient);
84 private void startSsh(final ChannelHandlerContext ctx, final SocketAddress address) {
85 logger.debug("Starting SSH to {} on channel: {}", address, ctx.channel());
87 final ConnectFuture sshConnectionFuture = sshClient.connect(authenticationHandler.getUsername(), address);
88 sshConnectionFuture.addListener(new SshFutureListener<ConnectFuture>() {
90 public void operationComplete(final ConnectFuture future) {
91 if (future.isConnected()) {
92 handleSshSessionCreated(future, ctx);
94 handleSshSetupFailure(ctx, future.getException());
100 private synchronized void handleSshSessionCreated(final ConnectFuture future, final ChannelHandlerContext ctx) {
102 logger.trace("SSH session created on channel: {}", ctx.channel());
104 session = future.getSession();
105 final AuthFuture authenticateFuture = authenticationHandler.authenticate(session);
106 authenticateFuture.addListener(new SshFutureListener<AuthFuture>() {
108 public void operationComplete(final AuthFuture future) {
109 if (future.isSuccess()) {
110 handleSshAuthenticated(session, ctx);
112 handleSshSetupFailure(ctx, future.getException());
116 } catch (final IOException e) {
117 handleSshSetupFailure(ctx, e);
121 private synchronized void handleSshAuthenticated(final ClientSession session, final ChannelHandlerContext ctx) {
123 logger.debug("SSH session authenticated on channel: {}, server version: {}", ctx.channel(), session.getServerVersion());
125 channel = session.createSubsystemChannel(SUBSYSTEM);
126 channel.setStreaming(ClientChannel.Streaming.Async);
127 channel.open().addListener(new SshFutureListener<OpenFuture>() {
129 public void operationComplete(final OpenFuture future) {
130 if(future.isOpened()) {
131 handleSshChanelOpened(ctx);
133 handleSshSetupFailure(ctx, future.getException());
139 } catch (final IOException e) {
140 handleSshSetupFailure(ctx, e);
144 private synchronized void handleSshChanelOpened(final ChannelHandlerContext ctx) {
145 logger.trace("SSH subsystem channel opened successfully on channel: {}", ctx.channel());
147 connectPromise.setSuccess();
148 connectPromise = null;
150 sshReadAsyncListener = new SshReadAsyncListener(this, ctx, channel.getAsyncOut());
151 // if readAsyncListener receives immediate close, it will close this handler and closing this handler sets channel variable to null
152 if(channel != null) {
153 sshWriteAsyncHandler = new SshWriteAsyncHandler(this, channel.getAsyncIn());
154 ctx.fireChannelActive();
158 private synchronized void handleSshSetupFailure(final ChannelHandlerContext ctx, final Throwable e) {
159 logger.warn("Unable to setup SSH connection on channel: {}", ctx.channel(), e);
160 connectPromise.setFailure(e);
161 connectPromise = null;
162 throw new IllegalStateException("Unable to setup SSH connection on channel: " + ctx.channel(), e);
166 public synchronized void write(final ChannelHandlerContext ctx, final Object msg, final ChannelPromise promise) {
167 sshWriteAsyncHandler.write(ctx, msg, promise);
171 public synchronized void connect(final ChannelHandlerContext ctx, final SocketAddress remoteAddress, final SocketAddress localAddress, final ChannelPromise promise) throws Exception {
172 this.connectPromise = promise;
173 startSsh(ctx, remoteAddress);
177 public void close(final ChannelHandlerContext ctx, final ChannelPromise promise) throws Exception {
178 disconnect(ctx, promise);
182 public synchronized void disconnect(final ChannelHandlerContext ctx, final ChannelPromise promise) {
183 if(sshReadAsyncListener != null) {
184 sshReadAsyncListener.close();
187 if(sshWriteAsyncHandler != null) {
188 sshWriteAsyncHandler.close();
191 if(session!= null && !session.isClosed() && !session.isClosing()) {
192 session.close(false).addListener(new SshFutureListener<CloseFuture>() {
194 public void operationComplete(final CloseFuture future) {
195 if (future.isClosed() == false) {
204 promise.setSuccess();
206 logger.debug("SSH session closed on channel: {}", ctx.channel());
207 ctx.fireChannelInactive();
211 * Listener over async input stream from SSH session.
212 * This listeners schedules reads in a loop until the session is closed or read fails.
214 private static class SshReadAsyncListener implements SshFutureListener<IoReadFuture>, AutoCloseable {
215 private static final int BUFFER_SIZE = 8192;
217 private final ChannelOutboundHandler asyncSshHandler;
218 private final ChannelHandlerContext ctx;
220 private IoInputStream asyncOut;
222 private IoReadFuture currentReadFuture;
224 public SshReadAsyncListener(final ChannelOutboundHandler asyncSshHandler, final ChannelHandlerContext ctx, final IoInputStream asyncOut) {
225 this.asyncSshHandler = asyncSshHandler;
227 this.asyncOut = asyncOut;
228 buf = new Buffer(BUFFER_SIZE);
229 asyncOut.read(buf).addListener(this);
233 public synchronized void operationComplete(final IoReadFuture future) {
234 if(future.getException() != null) {
235 if(asyncOut.isClosed() || asyncOut.isClosing()) {
237 logger.debug("Ssh session dropped on channel: {}", ctx.channel(), future.getException());
239 logger.warn("Exception while reading from SSH remote on channel {}", ctx.channel(), future.getException());
245 if (future.getRead() > 0) {
246 ctx.fireChannelRead(Unpooled.wrappedBuffer(buf.array(), 0, future.getRead()));
248 // Schedule next read
249 buf = new Buffer(BUFFER_SIZE);
250 currentReadFuture = asyncOut.read(buf);
251 currentReadFuture.addListener(this);
255 private void invokeDisconnect() {
257 asyncSshHandler.disconnect(ctx, ctx.newPromise());
258 } catch (final Exception e) {
259 // This should not happen
260 throw new IllegalStateException(e);
265 public synchronized void close() {
266 // Remove self as listener on close to prevent reading from closed input
267 if(currentReadFuture != null) {
268 currentReadFuture.removeListener(this);
275 private static final class SshWriteAsyncHandler implements AutoCloseable {
276 public static final int MAX_PENDING_WRITES = 100;
278 private final ChannelOutboundHandler channelHandler;
279 private IoOutputStream asyncIn;
281 // Counter that holds the amount of pending write messages
282 // Pending write can occur in case remote window is full
283 // In such case, we need to wait for the pending write to finish
284 private int pendingWriteCounter;
285 // Last write future, that can be pending
286 private IoWriteFuture lastWriteFuture;
288 public SshWriteAsyncHandler(final ChannelOutboundHandler channelHandler, final IoOutputStream asyncIn) {
289 this.channelHandler = channelHandler;
290 this.asyncIn = asyncIn;
295 public synchronized void write(final ChannelHandlerContext ctx, final Object msg, final ChannelPromise promise) {
297 if(asyncIn == null || asyncIn.isClosed() || asyncIn.isClosing()) {
298 // If we are closed/closing, set immediate fail
299 promise.setFailure(new IllegalStateException("Channel closed"));
301 lastWriteFuture = asyncIn.write(toBuffer(msg));
302 lastWriteFuture.addListener(new SshFutureListener<IoWriteFuture>() {
305 public void operationComplete(final IoWriteFuture future) {
306 ((ByteBuf) msg).release();
308 // Notify success or failure
309 if (future.isWritten()) {
310 promise.setSuccess();
312 promise.setFailure(future.getException());
315 // Reset last pending future
316 synchronized (SshWriteAsyncHandler.this) {
317 lastWriteFuture = null;
322 } catch (final WritePendingException e) {
323 // Check limit for pending writes
324 pendingWriteCounter++;
325 if(pendingWriteCounter > MAX_PENDING_WRITES) {
326 promise.setFailure(e);
327 handlePendingFailed(ctx, new IllegalStateException("Too much pending writes(" + MAX_PENDING_WRITES + ") on channel: " + ctx.channel() +
328 ", remote window is not getting read or is too small"));
331 logger.debug("Write pending to SSH remote on channel: {}, current pending count: {}", ctx.channel(), pendingWriteCounter);
333 // In case of pending, re-invoke write after pending is finished
334 Preconditions.checkNotNull(lastWriteFuture, "Write is pending, but there was no previous write attempt", e);
335 lastWriteFuture.addListener(new SshFutureListener<IoWriteFuture>() {
337 public void operationComplete(final IoWriteFuture future) {
338 if (future.isWritten()) {
339 synchronized (SshWriteAsyncHandler.this) {
340 // Pending done, decrease counter
341 pendingWriteCounter--;
343 write(ctx, msg, promise);
345 // Cannot reschedule pending, fail
346 handlePendingFailed(ctx, e);
354 private void handlePendingFailed(final ChannelHandlerContext ctx, final Exception e) {
355 logger.warn("Exception while writing to SSH remote on channel {}", ctx.channel(), e);
357 channelHandler.disconnect(ctx, ctx.newPromise());
358 } catch (final Exception ex) {
359 // This should not happen
360 throw new IllegalStateException(ex);
365 public void close() {
369 private Buffer toBuffer(final Object msg) {
370 // TODO Buffer vs ByteBuf translate, Can we handle that better ?
371 Preconditions.checkState(msg instanceof ByteBuf);
372 final ByteBuf byteBuf = (ByteBuf) msg;
373 final byte[] temp = new byte[byteBuf.readableBytes()];
374 byteBuf.readBytes(temp, 0, byteBuf.readableBytes());
375 return new Buffer(temp);