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;
76 private final String name;
78 // Initialized by connect()
80 private ChannelPromise connectPromise;
82 private AsyncSshHandlerWriter sshWriteAsyncHandler;
83 private NettyAwareChannelSubsystem channel;
84 private ClientSession session;
85 private FutureListener<Object> negotiationFutureListener;
87 private volatile boolean disconnected;
89 private AsyncSshHandler(final AuthenticationHandler authenticationHandler, final NetconfSshClient sshClient,
90 final @Nullable Future<?> negotiationFuture, final @Nullable String name) {
91 this.authenticationHandler = requireNonNull(authenticationHandler);
92 this.sshClient = requireNonNull(sshClient);
93 this.negotiationFuture = negotiationFuture;
94 this.name = name != null && !name.isBlank() ? name : "UNNAMED";
97 public AsyncSshHandler(final AuthenticationHandler authenticationHandler, final NetconfSshClient sshClient,
98 final @Nullable Future<?> negotiationFuture) {
99 this(authenticationHandler, sshClient, negotiationFuture, null);
103 * Constructor of {@code AsyncSshHandler}.
105 * @param authenticationHandler authentication handler
106 * @param sshClient started SshClient
108 public AsyncSshHandler(final AuthenticationHandler authenticationHandler, final NetconfSshClient sshClient) {
109 this(authenticationHandler, sshClient, null);
112 public static AsyncSshHandler createForNetconfSubsystem(final AuthenticationHandler authenticationHandler) {
113 return new AsyncSshHandler(authenticationHandler, DEFAULT_CLIENT);
117 * Create AsyncSshHandler for netconf subsystem. Negotiation future has to be set to success after successful
118 * netconf negotiation.
120 * @param authenticationHandler authentication handler
121 * @param negotiationFuture negotiation future
122 * @return {@code AsyncSshHandler}
124 public static AsyncSshHandler createForNetconfSubsystem(final AuthenticationHandler authenticationHandler,
125 final Future<?> negotiationFuture, final @Nullable NetconfSshClient sshClient,
126 final @Nullable String name) {
127 return new AsyncSshHandler(authenticationHandler, sshClient != null ? sshClient : DEFAULT_CLIENT,
128 negotiationFuture, name);
132 public synchronized void write(final ChannelHandlerContext ctx, final Object msg, final ChannelPromise promise) {
133 sshWriteAsyncHandler.write(ctx, msg, promise);
137 public synchronized void connect(final ChannelHandlerContext ctx, final SocketAddress remoteAddress,
138 final SocketAddress localAddress, final ChannelPromise promise) throws IOException {
139 LOG.debug("{}: SSH session connecting on channel {}. promise: {}", name, ctx.channel(), promise);
140 connectPromise = requireNonNull(promise);
142 if (negotiationFuture != null) {
143 negotiationFutureListener = future -> {
144 if (future.isSuccess()) {
145 promise.setSuccess();
148 //complete connection promise with netconf negotiation future
149 negotiationFuture.addListener(negotiationFutureListener);
152 LOG.debug("{}: Starting SSH to {} on channel: {}", name, remoteAddress, ctx.channel());
153 sshClient.connect(authenticationHandler.getUsername(), remoteAddress)
154 // FIXME: this is a blocking call, we should handle this with a concurrently-scheduled timeout. We do not
155 // have a Timer ready, so perhaps we should be using the event loop?
156 .verify(ctx.channel().config().getConnectTimeoutMillis(), TimeUnit.MILLISECONDS)
157 .addListener(future -> onConnectComplete(future, ctx));
160 private synchronized void onConnectComplete(final ConnectFuture connectFuture, final ChannelHandlerContext ctx) {
161 final var cause = connectFuture.getException();
163 onOpenFailure(ctx, cause);
167 final var clientSession = connectFuture.getSession();
168 LOG.trace("{}: SSH session {} created on channel: {}", name, clientSession, ctx.channel());
169 verify(clientSession instanceof NettyAwareClientSession, "Unexpected session %s", clientSession);
171 final var localSession = (NettyAwareClientSession) clientSession;
172 session = localSession;
174 final AuthFuture authFuture;
176 authFuture = authenticationHandler.authenticate(localSession);
177 } catch (final IOException e) {
178 onOpenFailure(ctx, e);
182 authFuture.addListener(future -> onAuthComplete(future, localSession, ctx));
185 private synchronized void onAuthComplete(final AuthFuture authFuture, final NettyAwareClientSession clientSession,
186 final ChannelHandlerContext ctx) {
187 final var cause = authFuture.getException();
189 onOpenFailure(ctx, new AuthenticationFailedException("Authentication failed", cause));
193 LOG.debug("{}: Skipping SSH subsystem allocation, channel: {}", name, ctx.channel());
197 LOG.debug("{}: SSH session authenticated on channel: {}, server version: {}", name, ctx.channel(),
198 clientSession.getServerVersion());
200 final OpenFuture openFuture;
202 channel = clientSession.createSubsystemChannel(SUBSYSTEM, ctx);
203 channel.setStreaming(ClientChannel.Streaming.Async);
204 openFuture = channel.open();
205 } catch (final IOException e) {
206 onOpenFailure(ctx, e);
210 openFuture.addListener(future -> ctx.executor().execute(() -> onOpenComplete(future, ctx)));
213 // This callback has to run on the channel's executor because it runs fireChannelActive(), which needs to be
214 // delivered synchronously. If we were to execute on some other thread we would end up delaying the event,
215 // potentially creating havoc in the pipeline.
216 private synchronized void onOpenComplete(final OpenFuture openFuture, final ChannelHandlerContext ctx) {
217 final var cause = openFuture.getException();
219 onOpenFailure(ctx, cause);
223 LOG.trace("{}: Skipping activation, channel: {}", name, ctx.channel());
227 LOG.trace("{}: SSH subsystem channel opened successfully on channel: {}", name, ctx.channel());
228 if (negotiationFuture == null) {
229 connectPromise.setSuccess();
232 sshWriteAsyncHandler = new AsyncSshHandlerWriter(channel.getAsyncIn());
233 ctx.fireChannelActive();
234 channel.onClose(() -> disconnect(ctx, ctx.newPromise()));
238 private void onOpenFailure(final ChannelHandlerContext ctx, final Throwable cause) {
239 LOG.warn("{}: Unable to setup SSH connection on channel: {}", name, ctx.channel(), cause);
241 // If the promise is not yet done, we have failed with initial connect and set connectPromise to failure
242 if (!connectPromise.isDone()) {
243 connectPromise.setFailure(cause);
246 disconnect(ctx, ctx.newPromise());
250 public void close(final ChannelHandlerContext ctx, final ChannelPromise promise) {
251 disconnect(ctx, promise);
255 public void disconnect(final ChannelHandlerContext ctx, final ChannelPromise promise) {
256 if (DISCONNECTED.compareAndSet(this, false, true)) {
257 ctx.executor().execute(() -> safelyDisconnect(ctx, promise));
261 // This method has the potential to interact with the channel pipeline, for example via fireChannelInactive(). These
262 // callbacks need to complete during execution of this method and therefore this method needs to be executing on
263 // the channel's executor.
264 @SuppressWarnings("checkstyle:IllegalCatch")
265 private synchronized void safelyDisconnect(final ChannelHandlerContext ctx, final ChannelPromise promise) {
266 LOG.trace("{}: Closing SSH session on channel: {} with connect promise in state: {}", name, ctx.channel(),
269 // If we have already succeeded and the session was dropped after,
270 // we need to fire inactive to notify reconnect logic
271 if (connectPromise.isSuccess()) {
272 ctx.fireChannelInactive();
275 if (sshWriteAsyncHandler != null) {
276 sshWriteAsyncHandler.close();
279 //If connection promise is not already set, it means negotiation failed
280 //we must set connection promise to failure
281 if (!connectPromise.isDone()) {
282 connectPromise.setFailure(new IllegalStateException("Negotiation failed"));
285 //Remove listener from negotiation future, we don't want notifications
286 //from negotiation anymore
287 if (negotiationFuture != null) {
288 negotiationFuture.removeListener(negotiationFutureListener);
291 if (session != null && !session.isClosed() && !session.isClosing()) {
292 session.close(false).addListener(future -> {
293 synchronized (this) {
294 if (!future.isClosed()) {
302 // Super disconnect is necessary in this case since we are using NioSocketChannel and it needs
303 // to cleanup its resources e.g. Socket that it tries to open in its constructor
304 // (https://bugs.opendaylight.org/show_bug.cgi?id=2430)
305 // TODO better solution would be to implement custom ChannelFactory + Channel
306 // that will use mina SSH lib internally: port this to custom channel implementation
308 // Disconnect has to be closed after inactive channel event was fired, because it interferes with it
309 super.disconnect(ctx, ctx.newPromise());
310 } catch (final Exception e) {
311 LOG.warn("{}: Unable to cleanup all resources for channel: {}. Ignoring.", name, ctx.channel(), e);
314 if (channel != null) {
315 //TODO: see if calling just close() is sufficient
316 //channel.close(false);
320 promise.setSuccess();
321 LOG.debug("{}: SSH session closed on channel: {}", name, ctx.channel());