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
8 package org.opendaylight.netconf.nettyutil.handler.ssh.client;
10 import static com.google.common.base.Verify.verify;
11 import static java.util.Objects.requireNonNull;
13 import io.netty.channel.ChannelHandlerContext;
14 import io.netty.channel.ChannelOutboundHandlerAdapter;
15 import io.netty.channel.ChannelPromise;
16 import io.netty.util.concurrent.Future;
17 import io.netty.util.concurrent.FutureListener;
18 import java.io.IOException;
19 import java.lang.invoke.MethodHandles;
20 import java.lang.invoke.VarHandle;
21 import java.net.SocketAddress;
22 import java.time.Duration;
23 import java.util.concurrent.TimeUnit;
24 import org.checkerframework.checker.lock.qual.GuardedBy;
25 import org.checkerframework.checker.lock.qual.Holding;
26 import org.eclipse.jdt.annotation.Nullable;
27 import org.opendaylight.netconf.nettyutil.handler.ssh.authentication.AuthenticationHandler;
28 import org.opendaylight.netconf.shaded.sshd.client.channel.ClientChannel;
29 import org.opendaylight.netconf.shaded.sshd.client.future.AuthFuture;
30 import org.opendaylight.netconf.shaded.sshd.client.future.ConnectFuture;
31 import org.opendaylight.netconf.shaded.sshd.client.future.OpenFuture;
32 import org.opendaylight.netconf.shaded.sshd.client.session.ClientSession;
33 import org.opendaylight.netconf.shaded.sshd.core.CoreModuleProperties;
34 import org.slf4j.Logger;
35 import org.slf4j.LoggerFactory;
38 * Netty SSH handler class. Acts as interface between Netty and SSH library.
40 public final class AsyncSshHandler extends ChannelOutboundHandlerAdapter {
41 private static final Logger LOG = LoggerFactory.getLogger(AsyncSshHandler.class);
42 private static final VarHandle DISCONNECTED;
46 DISCONNECTED = MethodHandles.lookup().findVarHandle(AsyncSshHandler.class, "disconnected", boolean.class);
47 } catch (NoSuchFieldException | IllegalAccessException e) {
48 throw new ExceptionInInitializerError(e);
52 public static final String SUBSYSTEM = "netconf";
54 public static final int SSH_DEFAULT_NIO_WORKERS = 8;
56 public static final NetconfSshClient DEFAULT_CLIENT;
59 final var c = new NetconfClientBuilder().build();
60 // Disable default timeouts from mina sshd
61 final var zero = Duration.ofMillis(0);
62 CoreModuleProperties.AUTH_TIMEOUT.set(c, zero);
63 CoreModuleProperties.IDLE_TIMEOUT.set(c, zero);
64 CoreModuleProperties.NIO2_READ_TIMEOUT.set(c, zero);
65 CoreModuleProperties.TCP_NODELAY.set(c, true);
67 // TODO make configurable, or somehow reuse netty threadpool
68 c.setNioWorkers(SSH_DEFAULT_NIO_WORKERS);
73 private final AuthenticationHandler authenticationHandler;
74 private final Future<?> negotiationFuture;
75 private final NetconfSshClient sshClient;
77 // Initialized by connect()
79 private ChannelPromise connectPromise;
81 private AsyncSshHandlerWriter sshWriteAsyncHandler;
82 private NettyAwareChannelSubsystem channel;
83 private ClientSession session;
84 private FutureListener<Object> negotiationFutureListener;
86 private volatile boolean disconnected;
88 public AsyncSshHandler(final AuthenticationHandler authenticationHandler, final NetconfSshClient sshClient,
89 final Future<?> negotiationFuture) {
90 this.authenticationHandler = requireNonNull(authenticationHandler);
91 this.sshClient = requireNonNull(sshClient);
92 this.negotiationFuture = negotiationFuture;
96 * Constructor of {@code AsyncSshHandler}.
98 * @param authenticationHandler authentication handler
99 * @param sshClient started SshClient
101 public AsyncSshHandler(final AuthenticationHandler authenticationHandler, final NetconfSshClient sshClient) {
102 this(authenticationHandler, sshClient, null);
105 public static AsyncSshHandler createForNetconfSubsystem(final AuthenticationHandler authenticationHandler) {
106 return new AsyncSshHandler(authenticationHandler, DEFAULT_CLIENT);
110 * Create AsyncSshHandler for netconf subsystem. Negotiation future has to be set to success after successful
111 * netconf negotiation.
113 * @param authenticationHandler authentication handler
114 * @param negotiationFuture negotiation future
115 * @return {@code AsyncSshHandler}
117 public static AsyncSshHandler createForNetconfSubsystem(final AuthenticationHandler authenticationHandler,
118 final Future<?> negotiationFuture, final @Nullable NetconfSshClient sshClient) {
119 return new AsyncSshHandler(authenticationHandler, sshClient != null ? sshClient : DEFAULT_CLIENT,
124 public synchronized void write(final ChannelHandlerContext ctx, final Object msg, final ChannelPromise promise) {
125 sshWriteAsyncHandler.write(ctx, msg, promise);
129 public synchronized void connect(final ChannelHandlerContext ctx, final SocketAddress remoteAddress,
130 final SocketAddress localAddress, final ChannelPromise promise) throws IOException {
131 LOG.debug("SSH session connecting on channel {}. promise: {}", ctx.channel(), promise);
132 connectPromise = requireNonNull(promise);
134 if (negotiationFuture != null) {
135 negotiationFutureListener = future -> {
136 if (future.isSuccess()) {
137 promise.setSuccess();
140 //complete connection promise with netconf negotiation future
141 negotiationFuture.addListener(negotiationFutureListener);
144 LOG.debug("Starting SSH to {} on channel: {}", remoteAddress, ctx.channel());
145 sshClient.connect(authenticationHandler.getUsername(), remoteAddress)
146 // FIXME: this is a blocking call, we should handle this with a concurrently-scheduled timeout. We do not
147 // have a Timer ready, so perhaps we should be using the event loop?
148 .verify(ctx.channel().config().getConnectTimeoutMillis(), TimeUnit.MILLISECONDS)
149 .addListener(future -> onConnectComplete(future, ctx));
152 private synchronized void onConnectComplete(final ConnectFuture connectFuture, final ChannelHandlerContext ctx) {
153 final var cause = connectFuture.getException();
155 onOpenFailure(ctx, cause);
159 final var clientSession = connectFuture.getSession();
160 LOG.trace("SSH session {} created on channel: {}", clientSession, ctx.channel());
161 verify(clientSession instanceof NettyAwareClientSession, "Unexpected session %s", clientSession);
163 final var localSession = (NettyAwareClientSession) clientSession;
164 session = localSession;
166 final AuthFuture authFuture;
168 authFuture = authenticationHandler.authenticate(localSession);
169 } catch (final IOException e) {
170 onOpenFailure(ctx, e);
174 authFuture.addListener(future -> onAuthComplete(future, localSession, ctx));
177 private synchronized void onAuthComplete(final AuthFuture authFuture, final NettyAwareClientSession clientSession,
178 final ChannelHandlerContext ctx) {
179 final var cause = authFuture.getException();
181 onOpenFailure(ctx, new AuthenticationFailedException("Authentication failed", cause));
185 LOG.debug("Skipping SSH subsystem allocation, channel: {}", ctx.channel());
189 LOG.debug("SSH session authenticated on channel: {}, server version: {}", ctx.channel(),
190 clientSession.getServerVersion());
192 final OpenFuture openFuture;
194 channel = clientSession.createSubsystemChannel(SUBSYSTEM, ctx);
195 channel.setStreaming(ClientChannel.Streaming.Async);
196 openFuture = channel.open();
197 } catch (final IOException e) {
198 onOpenFailure(ctx, e);
202 openFuture.addListener(future -> ctx.executor().execute(() -> onOpenComplete(future, ctx)));
205 // This callback has to run on the channel's executor because it runs fireChannelActive(), which needs to be
206 // delivered synchronously. If we were to execute on some other thread we would end up delaying the event,
207 // potentially creating havoc in the pipeline.
208 private synchronized void onOpenComplete(final OpenFuture openFuture, final ChannelHandlerContext ctx) {
209 final var cause = openFuture.getException();
211 onOpenFailure(ctx, cause);
215 LOG.trace("Skipping activation, channel: {}", ctx.channel());
219 LOG.trace("SSH subsystem channel opened successfully on channel: {}", ctx.channel());
220 if (negotiationFuture == null) {
221 connectPromise.setSuccess();
224 sshWriteAsyncHandler = new AsyncSshHandlerWriter(channel.getAsyncIn());
225 ctx.fireChannelActive();
226 channel.onClose(() -> disconnect(ctx, ctx.newPromise()));
230 private void onOpenFailure(final ChannelHandlerContext ctx, final Throwable cause) {
231 LOG.warn("Unable to setup SSH connection on channel: {}", ctx.channel(), cause);
233 // If the promise is not yet done, we have failed with initial connect and set connectPromise to failure
234 if (!connectPromise.isDone()) {
235 connectPromise.setFailure(cause);
238 disconnect(ctx, ctx.newPromise());
242 public void close(final ChannelHandlerContext ctx, final ChannelPromise promise) {
243 disconnect(ctx, promise);
247 public void disconnect(final ChannelHandlerContext ctx, final ChannelPromise promise) {
248 if (DISCONNECTED.compareAndSet(this, false, true)) {
249 ctx.executor().execute(() -> safelyDisconnect(ctx, promise));
253 // This method has the potential to interact with the channel pipeline, for example via fireChannelInactive(). These
254 // callbacks need to complete during execution of this method and therefore this method needs to be executing on
255 // the channel's executor.
256 @SuppressWarnings("checkstyle:IllegalCatch")
257 private synchronized void safelyDisconnect(final ChannelHandlerContext ctx, final ChannelPromise promise) {
258 LOG.trace("Closing SSH session on channel: {} with connect promise in state: {}", ctx.channel(),
261 // If we have already succeeded and the session was dropped after,
262 // we need to fire inactive to notify reconnect logic
263 if (connectPromise.isSuccess()) {
264 ctx.fireChannelInactive();
267 if (sshWriteAsyncHandler != null) {
268 sshWriteAsyncHandler.close();
271 //If connection promise is not already set, it means negotiation failed
272 //we must set connection promise to failure
273 if (!connectPromise.isDone()) {
274 connectPromise.setFailure(new IllegalStateException("Negotiation failed"));
277 //Remove listener from negotiation future, we don't want notifications
278 //from negotiation anymore
279 if (negotiationFuture != null) {
280 negotiationFuture.removeListener(negotiationFutureListener);
283 if (session != null && !session.isClosed() && !session.isClosing()) {
284 session.close(false).addListener(future -> {
285 synchronized (this) {
286 if (!future.isClosed()) {
294 // Super disconnect is necessary in this case since we are using NioSocketChannel and it needs
295 // to cleanup its resources e.g. Socket that it tries to open in its constructor
296 // (https://bugs.opendaylight.org/show_bug.cgi?id=2430)
297 // TODO better solution would be to implement custom ChannelFactory + Channel
298 // that will use mina SSH lib internally: port this to custom channel implementation
300 // Disconnect has to be closed after inactive channel event was fired, because it interferes with it
301 super.disconnect(ctx, ctx.newPromise());
302 } catch (final Exception e) {
303 LOG.warn("Unable to cleanup all resources for channel: {}. Ignoring.", ctx.channel(), e);
306 if (channel != null) {
307 //TODO: see if calling just close() is sufficient
308 //channel.close(false);
312 promise.setSuccess();
313 LOG.debug("SSH session closed on channel: {}", ctx.channel());