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.ChannelSubsystem;
29 import org.opendaylight.netconf.shaded.sshd.client.channel.ClientChannel;
30 import org.opendaylight.netconf.shaded.sshd.client.future.AuthFuture;
31 import org.opendaylight.netconf.shaded.sshd.client.future.ConnectFuture;
32 import org.opendaylight.netconf.shaded.sshd.client.future.OpenFuture;
33 import org.opendaylight.netconf.shaded.sshd.client.session.ClientSession;
34 import org.opendaylight.netconf.shaded.sshd.core.CoreModuleProperties;
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 final class AsyncSshHandler extends ChannelOutboundHandlerAdapter {
42 private static final Logger LOG = LoggerFactory.getLogger(AsyncSshHandler.class);
43 private static final VarHandle DISCONNECTED;
47 DISCONNECTED = MethodHandles.lookup().findVarHandle(AsyncSshHandler.class, "disconnected", boolean.class);
48 } catch (NoSuchFieldException | IllegalAccessException e) {
49 throw new ExceptionInInitializerError(e);
53 public static final String SUBSYSTEM = "netconf";
55 public static final int SSH_DEFAULT_NIO_WORKERS = 8;
57 public static final NetconfSshClient DEFAULT_CLIENT;
60 final var c = new NetconfClientBuilder().build();
61 // Disable default timeouts from mina sshd
62 final var zero = Duration.ofMillis(0);
63 CoreModuleProperties.AUTH_TIMEOUT.set(c, zero);
64 CoreModuleProperties.IDLE_TIMEOUT.set(c, zero);
65 CoreModuleProperties.NIO2_READ_TIMEOUT.set(c, zero);
66 CoreModuleProperties.TCP_NODELAY.set(c, true);
68 // TODO make configurable, or somehow reuse netty threadpool
69 c.setNioWorkers(SSH_DEFAULT_NIO_WORKERS);
74 private final AuthenticationHandler authenticationHandler;
75 private final Future<?> negotiationFuture;
76 private final NetconfSshClient sshClient;
77 private final String name;
79 // Initialized by connect()
81 private ChannelPromise connectPromise;
83 private AsyncSshHandlerWriter sshWriteAsyncHandler;
84 private ChannelSubsystem channel;
85 private ClientSession session;
86 private FutureListener<Object> negotiationFutureListener;
88 private volatile boolean disconnected;
90 private AsyncSshHandler(final AuthenticationHandler authenticationHandler, final NetconfSshClient sshClient,
91 final @Nullable Future<?> negotiationFuture, final @Nullable String name) {
92 this.authenticationHandler = requireNonNull(authenticationHandler);
93 this.sshClient = requireNonNull(sshClient);
94 this.negotiationFuture = negotiationFuture;
95 this.name = name != null && !name.isBlank() ? name : "UNNAMED";
98 public AsyncSshHandler(final AuthenticationHandler authenticationHandler, final NetconfSshClient sshClient,
99 final @Nullable Future<?> negotiationFuture) {
100 this(authenticationHandler, sshClient, negotiationFuture, null);
104 * Constructor of {@code AsyncSshHandler}.
106 * @param authenticationHandler authentication handler
107 * @param sshClient started SshClient
109 public AsyncSshHandler(final AuthenticationHandler authenticationHandler, final NetconfSshClient sshClient) {
110 this(authenticationHandler, sshClient, null);
113 public static AsyncSshHandler createForNetconfSubsystem(final AuthenticationHandler authenticationHandler) {
114 return new AsyncSshHandler(authenticationHandler, DEFAULT_CLIENT);
118 * Create AsyncSshHandler for netconf subsystem. Negotiation future has to be set to success after successful
119 * netconf negotiation.
121 * @param authenticationHandler authentication handler
122 * @param negotiationFuture negotiation future
123 * @return {@code AsyncSshHandler}
125 public static AsyncSshHandler createForNetconfSubsystem(final AuthenticationHandler authenticationHandler,
126 final Future<?> negotiationFuture, final @Nullable NetconfSshClient sshClient,
127 final @Nullable String name) {
128 return new AsyncSshHandler(authenticationHandler, sshClient != null ? sshClient : DEFAULT_CLIENT,
129 negotiationFuture, name);
133 public synchronized void write(final ChannelHandlerContext ctx, final Object msg, final ChannelPromise promise) {
134 sshWriteAsyncHandler.write(ctx, msg, promise);
138 public synchronized void connect(final ChannelHandlerContext ctx, final SocketAddress remoteAddress,
139 final SocketAddress localAddress, final ChannelPromise promise) throws IOException {
140 LOG.debug("{}: SSH session connecting on channel {}. promise: {}", name, ctx.channel(), promise);
141 connectPromise = requireNonNull(promise);
143 if (negotiationFuture != null) {
144 negotiationFutureListener = future -> {
145 if (future.isSuccess()) {
146 promise.setSuccess();
149 //complete connection promise with netconf negotiation future
150 negotiationFuture.addListener(negotiationFutureListener);
153 LOG.debug("{}: Starting SSH to {} on channel: {}", name, remoteAddress, ctx.channel());
154 sshClient.connect(authenticationHandler.getUsername(), remoteAddress)
155 // FIXME: this is a blocking call, we should handle this with a concurrently-scheduled timeout. We do not
156 // have a Timer ready, so perhaps we should be using the event loop?
157 .verify(ctx.channel().config().getConnectTimeoutMillis(), TimeUnit.MILLISECONDS)
158 .addListener(future -> onConnectComplete(future, ctx));
161 private synchronized void onConnectComplete(final ConnectFuture connectFuture, final ChannelHandlerContext ctx) {
162 final var cause = connectFuture.getException();
164 onOpenFailure(ctx, cause);
168 final var clientSession = connectFuture.getSession();
169 LOG.trace("{}: SSH session {} created on channel: {}", name, clientSession, ctx.channel());
170 verify(clientSession instanceof NettyAwareClientSession, "Unexpected session %s", clientSession);
172 final var localSession = (NettyAwareClientSession) clientSession;
173 session = localSession;
175 final AuthFuture authFuture;
177 authFuture = authenticationHandler.authenticate(localSession);
178 } catch (final IOException e) {
179 onOpenFailure(ctx, e);
183 authFuture.addListener(future -> onAuthComplete(future, localSession, ctx));
186 private synchronized void onAuthComplete(final AuthFuture authFuture, final NettyAwareClientSession clientSession,
187 final ChannelHandlerContext ctx) {
188 final var cause = authFuture.getException();
190 onOpenFailure(ctx, new AuthenticationFailedException("Authentication failed", cause));
194 LOG.debug("{}: Skipping SSH subsystem allocation, channel: {}", name, ctx.channel());
198 LOG.debug("{}: SSH session authenticated on channel: {}, server version: {}", name, ctx.channel(),
199 clientSession.getServerVersion());
201 final OpenFuture openFuture;
203 channel = clientSession.createSubsystemChannel(SUBSYSTEM, ctx);
204 channel.setStreaming(ClientChannel.Streaming.Async);
205 openFuture = channel.open();
206 } catch (final IOException e) {
207 onOpenFailure(ctx, e);
211 openFuture.addListener(future -> ctx.executor().execute(() -> onOpenComplete(future, ctx)));
214 // This callback has to run on the channel's executor because it runs fireChannelActive(), which needs to be
215 // delivered synchronously. If we were to execute on some other thread we would end up delaying the event,
216 // potentially creating havoc in the pipeline.
217 private synchronized void onOpenComplete(final OpenFuture openFuture, final ChannelHandlerContext ctx) {
218 final var cause = openFuture.getException();
220 onOpenFailure(ctx, cause);
224 LOG.trace("{}: Skipping activation, channel: {}", name, ctx.channel());
228 LOG.trace("{}: SSH subsystem channel opened successfully on channel: {}", name, ctx.channel());
229 if (negotiationFuture == null) {
230 connectPromise.setSuccess();
233 sshWriteAsyncHandler = new AsyncSshHandlerWriter(channel.getAsyncIn());
234 ctx.fireChannelActive();
235 channel.onClose(() -> disconnect(ctx, ctx.newPromise()));
239 private void onOpenFailure(final ChannelHandlerContext ctx, final Throwable cause) {
240 LOG.warn("{}: Unable to setup SSH connection on channel: {}", name, ctx.channel(), cause);
242 // If the promise is not yet done, we have failed with initial connect and set connectPromise to failure
243 if (!connectPromise.isDone()) {
244 connectPromise.setFailure(cause);
247 disconnect(ctx, ctx.newPromise());
251 public void close(final ChannelHandlerContext ctx, final ChannelPromise promise) {
252 disconnect(ctx, promise);
256 public void disconnect(final ChannelHandlerContext ctx, final ChannelPromise promise) {
257 if (DISCONNECTED.compareAndSet(this, false, true)) {
258 ctx.executor().execute(() -> safelyDisconnect(ctx, promise));
262 // This method has the potential to interact with the channel pipeline, for example via fireChannelInactive(). These
263 // callbacks need to complete during execution of this method and therefore this method needs to be executing on
264 // the channel's executor.
265 @SuppressWarnings("checkstyle:IllegalCatch")
266 private synchronized void safelyDisconnect(final ChannelHandlerContext ctx, final ChannelPromise promise) {
267 LOG.trace("{}: Closing SSH session on channel: {} with connect promise in state: {}", name, ctx.channel(),
270 // If we have already succeeded and the session was dropped after,
271 // we need to fire inactive to notify reconnect logic
272 if (connectPromise.isSuccess()) {
273 ctx.fireChannelInactive();
276 if (sshWriteAsyncHandler != null) {
277 sshWriteAsyncHandler.close();
280 //If connection promise is not already set, it means negotiation failed
281 //we must set connection promise to failure
282 if (!connectPromise.isDone()) {
283 connectPromise.setFailure(new IllegalStateException("Negotiation failed"));
286 //Remove listener from negotiation future, we don't want notifications
287 //from negotiation anymore
288 if (negotiationFuture != null) {
289 negotiationFuture.removeListener(negotiationFutureListener);
292 if (session != null && !session.isClosed() && !session.isClosing()) {
293 session.close(false).addListener(future -> {
294 synchronized (this) {
295 if (!future.isClosed()) {
303 // Super disconnect is necessary in this case since we are using NioSocketChannel and it needs
304 // to cleanup its resources e.g. Socket that it tries to open in its constructor
305 // (https://bugs.opendaylight.org/show_bug.cgi?id=2430)
306 // TODO better solution would be to implement custom ChannelFactory + Channel
307 // that will use mina SSH lib internally: port this to custom channel implementation
309 // Disconnect has to be closed after inactive channel event was fired, because it interferes with it
310 super.disconnect(ctx, ctx.newPromise());
311 } catch (final Exception e) {
312 LOG.warn("{}: Unable to cleanup all resources for channel: {}. Ignoring.", name, ctx.channel(), e);
315 if (channel != null) {
316 channel.close(false);
319 promise.setSuccess();
320 LOG.debug("{}: SSH session closed on channel: {}", name, ctx.channel());