| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| |
| package org.apache.guacamole.tunnel.websocket.tomcat; |
| |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.io.Reader; |
| import java.nio.ByteBuffer; |
| import java.nio.CharBuffer; |
| import java.util.List; |
| import javax.servlet.http.HttpServletRequest; |
| import org.apache.guacamole.GuacamoleException; |
| import org.apache.guacamole.io.GuacamoleReader; |
| import org.apache.guacamole.io.GuacamoleWriter; |
| import org.apache.guacamole.net.GuacamoleTunnel; |
| import org.apache.catalina.websocket.StreamInbound; |
| import org.apache.catalina.websocket.WebSocketServlet; |
| import org.apache.catalina.websocket.WsOutbound; |
| import org.apache.guacamole.GuacamoleClientException; |
| import org.apache.guacamole.GuacamoleConnectionClosedException; |
| import org.apache.guacamole.protocol.FilteredGuacamoleWriter; |
| import org.apache.guacamole.protocol.GuacamoleFilter; |
| import org.apache.guacamole.protocol.GuacamoleInstruction; |
| import org.apache.guacamole.tunnel.http.HTTPTunnelRequest; |
| import org.apache.guacamole.tunnel.TunnelRequest; |
| import org.apache.guacamole.protocol.GuacamoleStatus; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| /** |
| * A WebSocketServlet partial re-implementation of GuacamoleTunnelServlet. |
| */ |
| public abstract class GuacamoleWebSocketTunnelServlet extends WebSocketServlet { |
| |
| /** |
| * The default, minimum buffer size for instructions. |
| */ |
| private static final int BUFFER_SIZE = 8192; |
| |
| /** |
| * The opcode of the instruction used to indicate a connection stability |
| * test ping request or response. Note that this instruction is |
| * encapsulated within an internal tunnel instruction (with the opcode |
| * being the empty string), thus this will actually be the value of the |
| * first element of the received instruction. |
| */ |
| private static final String PING_OPCODE = "ping"; |
| |
| /** |
| * Logger for this class. |
| */ |
| private final Logger logger = LoggerFactory.getLogger(GuacamoleWebSocketTunnelServlet.class); |
| |
| /** |
| * Sends the given Guacamole and WebSocket numeric status |
| * on the given WebSocket connection and closes the |
| * connection. |
| * |
| * @param outbound |
| * The outbound WebSocket connection to close. |
| * |
| * @param guacamoleStatusCode |
| * The status to send. |
| * |
| * @param webSocketCode |
| * The numeric WebSocket status code to send. |
| */ |
| private void closeConnection(WsOutbound outbound, int guacamoleStatusCode, |
| int webSocketCode) { |
| |
| try { |
| byte[] message = Integer.toString(guacamoleStatusCode).getBytes("UTF-8"); |
| outbound.close(webSocketCode, ByteBuffer.wrap(message)); |
| } |
| catch (IOException e) { |
| logger.debug("Unable to close WebSocket tunnel.", e); |
| } |
| |
| } |
| |
| /** |
| * Sends the given status on the given WebSocket connection |
| * and closes the connection. |
| * |
| * @param outbound |
| * The outbound WebSocket connection to close. |
| * |
| * @param guacStatus |
| * The status to send. |
| */ |
| private void closeConnection(WsOutbound outbound, |
| GuacamoleStatus guacStatus) { |
| |
| closeConnection(outbound, guacStatus.getGuacamoleStatusCode(), |
| guacStatus.getWebSocketCode()); |
| |
| } |
| |
| @Override |
| protected String selectSubProtocol(List<String> subProtocols) { |
| |
| // Search for expected protocol |
| for (String protocol : subProtocols) |
| if ("guacamole".equals(protocol)) |
| return "guacamole"; |
| |
| // Otherwise, fail |
| return null; |
| |
| } |
| |
| @Override |
| public StreamInbound createWebSocketInbound(String protocol, |
| HttpServletRequest request) { |
| |
| final TunnelRequest tunnelRequest = new HTTPTunnelRequest(request); |
| |
| // Return new WebSocket which communicates through tunnel |
| return new StreamInbound() { |
| |
| /** |
| * The GuacamoleTunnel associated with the connected WebSocket. If |
| * the WebSocket has not yet been connected, this will be null. |
| */ |
| private GuacamoleTunnel tunnel = null; |
| |
| /** |
| * The outbound half of the WebSocket connection. This value will |
| * always be non-null if tunnel is non-null. |
| */ |
| private WsOutbound outbound = null; |
| |
| /** |
| * Sends a Guacamole instruction along the outbound WebSocket |
| * connection to the connected Guacamole client. If an instruction |
| * is already in the process of being sent by another thread, this |
| * function will block until in-progress instructions are complete. |
| * |
| * @param instruction |
| * The instruction to send. |
| * |
| * @throws IOException |
| * If an I/O error occurs preventing the given instruction from |
| * being sent. |
| */ |
| private void sendInstruction(CharSequence instruction) |
| throws IOException { |
| |
| // NOTE: Synchronization on the non-final remote field here is |
| // intentional. The outbound websocket connection is only |
| // sensitive to simultaneous attempts to send messages with |
| // respect to itself. If the connection changes, then |
| // synchronization need only be performed in context of the new |
| // connection |
| synchronized (outbound) { |
| outbound.writeTextMessage(CharBuffer.wrap(instruction)); |
| } |
| |
| } |
| |
| /** |
| * Sends a Guacamole instruction along the outbound WebSocket |
| * connection to the connected Guacamole client. If an instruction |
| * is already in the process of being sent by another thread, this |
| * function will block until in-progress instructions are complete. |
| * |
| * @param instruction |
| * The instruction to send. |
| * |
| * @throws IOException |
| * If an I/O error occurs preventing the given instruction from being |
| * sent. |
| */ |
| private void sendInstruction(GuacamoleInstruction instruction) |
| throws IOException { |
| sendInstruction(instruction.toString()); |
| } |
| |
| @Override |
| protected void onTextData(Reader reader) throws IOException { |
| |
| // Ignore inbound messages if there is no associated tunnel |
| if (tunnel == null) |
| return; |
| |
| // Filter received instructions, handling tunnel-internal |
| // instructions without passing through to guacd |
| GuacamoleWriter writer = new FilteredGuacamoleWriter(tunnel.acquireWriter(), new GuacamoleFilter() { |
| |
| @Override |
| public GuacamoleInstruction filter(GuacamoleInstruction instruction) |
| throws GuacamoleException { |
| |
| // Filter out all tunnel-internal instructions |
| if (instruction.getOpcode().equals(GuacamoleTunnel.INTERNAL_DATA_OPCODE)) { |
| |
| // Respond to ping requests |
| List<String> args = instruction.getArgs(); |
| if (args.size() >= 2 && args.get(0).equals(PING_OPCODE)) { |
| |
| try { |
| sendInstruction(new GuacamoleInstruction( |
| GuacamoleTunnel.INTERNAL_DATA_OPCODE, |
| PING_OPCODE, args.get(1) |
| )); |
| } |
| catch (IOException e) { |
| logger.debug("Unable to send \"ping\" response for WebSocket tunnel.", e); |
| } |
| |
| } |
| |
| return null; |
| |
| } |
| |
| // Pass through all non-internal instructions untouched |
| return instruction; |
| |
| } |
| |
| }); |
| |
| // Write all available data |
| try { |
| |
| char[] buffer = new char[BUFFER_SIZE]; |
| |
| int num_read; |
| while ((num_read = reader.read(buffer)) > 0) |
| writer.write(buffer, 0, num_read); |
| |
| } |
| catch (GuacamoleConnectionClosedException e) { |
| logger.debug("Connection to guacd closed.", e); |
| } |
| catch (GuacamoleException e) { |
| logger.debug("WebSocket tunnel write failed.", e); |
| } |
| |
| tunnel.releaseWriter(); |
| } |
| |
| @Override |
| public void onOpen(final WsOutbound outbound) { |
| |
| // Store outbound connection for future use via sendInstruction() |
| this.outbound = outbound; |
| |
| try { |
| tunnel = doConnect(tunnelRequest); |
| } |
| catch (GuacamoleException e) { |
| logger.error("Creation of WebSocket tunnel to guacd failed: {}", e.getMessage()); |
| logger.debug("Error connecting WebSocket tunnel.", e); |
| closeConnection(outbound, e.getStatus().getGuacamoleStatusCode(), |
| e.getWebSocketCode()); |
| return; |
| } |
| |
| // Do not start connection if tunnel does not exist |
| if (tunnel == null) { |
| closeConnection(outbound, GuacamoleStatus.RESOURCE_NOT_FOUND); |
| return; |
| } |
| |
| Thread readThread = new Thread() { |
| |
| @Override |
| public void run() { |
| |
| StringBuilder buffer = new StringBuilder(BUFFER_SIZE); |
| GuacamoleReader reader = tunnel.acquireReader(); |
| char[] readMessage; |
| |
| try { |
| |
| // Send tunnel UUID |
| sendInstruction(new GuacamoleInstruction( |
| GuacamoleTunnel.INTERNAL_DATA_OPCODE, |
| tunnel.getUUID().toString() |
| )); |
| |
| try { |
| |
| // Attempt to read |
| while ((readMessage = reader.read()) != null) { |
| |
| // Buffer message |
| buffer.append(readMessage); |
| |
| // Flush if we expect to wait or buffer is getting full |
| if (!reader.available() || buffer.length() >= BUFFER_SIZE) { |
| sendInstruction(CharBuffer.wrap(buffer)); |
| buffer.setLength(0); |
| } |
| |
| } |
| |
| // No more data |
| closeConnection(outbound, GuacamoleStatus.SUCCESS); |
| |
| } |
| |
| // Catch any thrown guacamole exception and attempt |
| // to pass within the WebSocket connection, logging |
| // each error appropriately. |
| catch (GuacamoleClientException e) { |
| logger.info("WebSocket connection terminated: {}", e.getMessage()); |
| logger.debug("WebSocket connection terminated due to client error.", e); |
| closeConnection(outbound, e.getStatus().getGuacamoleStatusCode(), |
| e.getWebSocketCode()); |
| } |
| catch (GuacamoleConnectionClosedException e) { |
| logger.debug("Connection to guacd closed.", e); |
| closeConnection(outbound, GuacamoleStatus.SUCCESS); |
| } |
| catch (GuacamoleException e) { |
| logger.error("Connection to guacd terminated abnormally: {}", e.getMessage()); |
| logger.debug("Internal error during connection to guacd.", e); |
| closeConnection(outbound, e.getStatus().getGuacamoleStatusCode(), |
| e.getWebSocketCode()); |
| } |
| |
| } |
| catch (IOException e) { |
| logger.debug("I/O error prevents further reads.", e); |
| closeConnection(outbound, GuacamoleStatus.SERVER_ERROR); |
| } |
| |
| } |
| |
| }; |
| |
| readThread.start(); |
| |
| } |
| |
| @Override |
| public void onClose(int i) { |
| try { |
| if (tunnel != null) |
| tunnel.close(); |
| } |
| catch (GuacamoleException e) { |
| logger.debug("Unable to close connection to guacd.", e); |
| } |
| } |
| |
| @Override |
| protected void onBinaryData(InputStream in) throws IOException { |
| throw new UnsupportedOperationException("Not supported yet."); |
| } |
| |
| }; |
| |
| } |
| |
| /** |
| * Called whenever the JavaScript Guacamole client makes a connection |
| * request. It it up to the implementor of this function to define what |
| * conditions must be met for a tunnel to be configured and returned as a |
| * result of this connection request (whether some sort of credentials must |
| * be specified, for example). |
| * |
| * @param request |
| * The TunnelRequest associated with the connection request received. |
| * Any parameters specified along with the connection request can be |
| * read from this object. |
| * |
| * @return |
| * A newly constructed GuacamoleTunnel if successful, null otherwise. |
| * |
| * @throws GuacamoleException |
| * If an error occurs while constructing the GuacamoleTunnel, or if the |
| * conditions required for connection are not met. |
| */ |
| protected abstract GuacamoleTunnel doConnect(TunnelRequest request) |
| throws GuacamoleException; |
| |
| } |
| |
