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com.sshtools.server.callback.CallbackForwardingChannel Maven / Gradle / Ivy
package com.sshtools.server.callback;
/*-
* #%L
* Callback Server API
* %%
* Copyright (C) 2002 - 2024 JADAPTIVE Limited
* %%
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Lesser Public License for more details.
*
* You should have received a copy of the GNU General Lesser Public
* License along with this program. If not, see
* .
* #L%
*/
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.Objects;
import com.sshtools.client.SshClientContext;
import com.sshtools.common.forwarding.ForwardingPolicy;
import com.sshtools.common.logger.Log;
import com.sshtools.common.nio.WriteOperationRequest;
import com.sshtools.common.ssh.ChannelOpenException;
import com.sshtools.common.ssh.ConnectionAwareTask;
import com.sshtools.common.ssh.Context;
import com.sshtools.common.ssh.ExecutorOperationQueues;
import com.sshtools.common.ssh.SshConnection;
import com.sshtools.common.util.ByteArrayReader;
import com.sshtools.common.util.ByteArrayWriter;
import com.sshtools.synergy.ssh.ForwardingChannel;
import com.sshtools.synergy.ssh.LocalForwardingChannel;
import com.sshtools.synergy.ssh.SshContext;
public class CallbackForwardingChannel extends ForwardingChannel {
static final String DIRECT_STREAM_LOCAL_CHANNEL = "[email protected] ";
CallbackForwardingChannel channel;
SshConnection callbackClient;
final static Integer CHANNEL_QUEUE = ExecutorOperationQueues.generateUniqueQueue("callbackDataQueue");
public CallbackForwardingChannel(Context ctx, SshConnection callbackClient) {
this(LocalForwardingChannel.LOCAL_FORWARDING_CHANNEL_TYPE, ctx, callbackClient);
this.callbackClient = callbackClient;
}
public CallbackForwardingChannel(String channel, Context ctx, SshConnection callbackClient) {
super(channel,
ctx.getPolicy(ForwardingPolicy.class).getForwardingMaxPacketSize(),
ctx.getPolicy(ForwardingPolicy.class).getForwardingMaxWindowSize(),
ctx.getPolicy(ForwardingPolicy.class).getForwardingMaxWindowSize(),
ctx.getPolicy(ForwardingPolicy.class).getForwardingMinWindowSize(),
true);
this.callbackClient = callbackClient;
}
public CallbackForwardingChannel(Context ctx, SshConnection callbackClient, String hostToConnect, int portToConnect) {
super(LocalForwardingChannel.LOCAL_FORWARDING_CHANNEL_TYPE,
ctx.getPolicy(ForwardingPolicy.class).getForwardingMaxPacketSize(),
ctx.getPolicy(ForwardingPolicy.class).getForwardingMaxWindowSize(),
ctx.getPolicy(ForwardingPolicy.class).getForwardingMaxWindowSize(),
ctx.getPolicy(ForwardingPolicy.class).getForwardingMinWindowSize(),
true);
this.callbackClient = callbackClient;
this.hostToConnect = hostToConnect;
this.portToConnect = portToConnect;
}
public void setBoundChannel(CallbackForwardingChannel channel) {
this.channel = channel;
}
/**
* Constructs a forwarding channel of the type "forwarded-tcpip"
*
* @param addressToBind
* String
* @param portToBind
* int
* @param socketChannel
* SocketChannel
*/
public CallbackForwardingChannel(String channelType, SshConnection con, String hostToConnect, int portToConnect) {
super(channelType, con.getContext().getPolicy(ForwardingPolicy.class).getForwardingMaxPacketSize(),
con.getContext().getPolicy(ForwardingPolicy.class).getForwardingMaxWindowSize(),
con.getContext().getPolicy(ForwardingPolicy.class).getForwardingMaxWindowSize(),
con.getContext().getPolicy(ForwardingPolicy.class).getForwardingMinWindowSize(),
true);
this.hostToConnect = hostToConnect;
this.portToConnect = portToConnect;
}
/**
* Constructs a forwarding channel of the type "forwarded-tcpip"
*
* @param addressToBind
* String
* @param portToBind
* int
* @param socketChannel
* SocketChannel
*/
public CallbackForwardingChannel(String channelType, Context ctx, SshConnection con, String hostToConnect, int portToConnect) {
super(channelType, con.getContext().getPolicy(ForwardingPolicy.class).getForwardingMaxPacketSize(),
ctx.getPolicy(ForwardingPolicy.class).getForwardingMaxWindowSize(),
ctx.getPolicy(ForwardingPolicy.class).getForwardingMaxWindowSize(),
ctx.getPolicy(ForwardingPolicy.class).getForwardingMinWindowSize(),
true);
this.hostToConnect = hostToConnect;
this.portToConnect = portToConnect;
}
/**
* Create the forwarding channel.
*
* @return byte[]
*/
protected byte[] createChannel() throws IOException {
if(getChannelType().equals(DIRECT_STREAM_LOCAL_CHANNEL)) {
try(var baw = new ByteArrayWriter()) {
baw.writeString(hostToConnect);
baw.writeString(""); // Reserved
baw.writeInt(0); // Reserved
return baw.toByteArray();
}
}
try(var baw = new ByteArrayWriter()) {
baw.writeString(hostToConnect);
baw.writeInt(portToConnect);
baw.writeString(originatingHost = con.getRemoteIPAddress());
baw.writeInt(originatingPort = con.getRemotePort());
return baw.toByteArray();
}
}
/**
* Open a forwarding channel.
*
* @param requestdata
* byte[]
* @return byte[]
* @throws WriteOperationRequest
* @throws ChannelOpenException
*/
protected byte[] openChannel(byte[] requestdata)
throws WriteOperationRequest, ChannelOpenException {
ByteArrayReader bar = new ByteArrayReader(requestdata);
try {
if(getChannelType().equals(DIRECT_STREAM_LOCAL_CHANNEL)) {
hostToConnect = bar.readString(); // socket path
bar.readString(); // reserved
bar.readInt(); // reserved
}
else {
hostToConnect = bar.readString();
portToConnect = (int) bar.readInt();
originatingHost = bar.readString();
originatingPort = (int) bar.readInt();
}
boolean success = checkPermissions();
if(Log.isDebugEnabled()) {
Log.debug("Forwarding policy has "
+ (success ? "authorized" : "denied") + " "
+ connection.getUsername()
+ (success ? " to open" : " from opening")
+ " a " + getChannelType() + " callback forwarding channel to " + hostToConnect
+ ":" + portToConnect);
}
if (!success) {
throw new ChannelOpenException("User does not have permission",
ChannelOpenException.ADMINISTRATIVIVELY_PROHIBITED);
}
if(Objects.isNull(callbackClient)) {
throw new ChannelOpenException(
String.format("Callback client %s is not connected", hostToConnect),
ChannelOpenException.CONNECT_FAILED);
}
con.addTask(new ConnectionAwareTask(con) {
@Override
protected void doTask() throws Throwable {
channel = new CallbackForwardingChannel(getChannelType(),
connection.getContext(), callbackClient, hostToConnect, portToConnect);
channel.setBoundChannel(CallbackForwardingChannel.this);
callbackClient.openChannel(channel);
channel.getOpenFuture().waitFor(30000L);
if(channel.getOpenFuture().isSuccess()) {
connection.sendChannelOpenConfirmation(
CallbackForwardingChannel.this, null);
} else {
connection.sendChannelOpenFailure(CallbackForwardingChannel.this,
ChannelOpenException.CONNECT_FAILED,
"Callback client failed to complete channel open within timeout period");
}
}
});
} catch (Throwable ex) {
throw new ChannelOpenException(
ex.getMessage(),
ChannelOpenException.CONNECT_FAILED);
} finally {
bar.close();
}
// Throw an WriteOperationRequest so that we can perform the
// channel open confirmation or failure when the socket has
// connected
throw new WriteOperationRequest();
}
protected boolean checkPermissions() {
return getContext().getForwardingPolicy().checkHostPermitted(
getConnectionProtocol().getTransport().getConnection(), hostToConnect,
portToConnect);
}
/**
* Called when the forwarded sockets selector has been registered with a
* {@link com,maverick.nio.SelectorThread}.
*/
protected synchronized void onRegistrationComplete() {
// Now do nothing, connect is called only if it returns false above
// and that means the connect procedure is already underway.
if(Log.isDebugEnabled()) {
Log.debug("Registration Complete");
}
}
/**
* Called when the channel has been confirmed as open.
*/
protected synchronized void onChannelOpenConfirmation() {
}
@Override
protected void onChannelData(ByteBuffer data) {
con.addTask(CHANNEL_QUEUE, new ConnectionAwareTask(con) {
@Override
protected void doTask() throws Throwable {
channel.sendChannelDataAndBlock(data);
evaluateWindowSpace();
}
});
}
protected void onChannelOpenFailure() {
}
@Override
protected void onChannelFree() {
}
@Override
protected void onChannelClosed() {
con.addTask(CHANNEL_QUEUE, new ConnectionAwareTask(con) {
@Override
protected void doTask() throws Throwable {
channel.close();
}
});
}
@Override
protected void onChannelOpen() {
}
@Override
protected void onChannelClosing() {
}
@Override
protected void onChannelRequest(String type, boolean wantreply, byte[] requestdata) {
}
@Override
protected void onRemoteEOF() {
channel.sendEOF();
}
@Override
protected void onLocalEOF() {
}
}
