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   1 /**
   2  * Copyright (c) 2010-2023 Contributors to the openHAB project
   3  *
   4  * See the NOTICE file(s) distributed with this work for additional
   5  * information.
   6  *
   7  * This program and the accompanying materials are made available under the
   8  * terms of the Eclipse Public License 2.0 which is available at
   9  * http://www.eclipse.org/legal/epl-2.0
  10  *
  11  * SPDX-License-Identifier: EPL-2.0
  12  */
  13 package org.openhab.binding.powermax.internal.connector;
  14
  15 import java.io.IOException;
  16 import java.io.InterruptedIOException;
  17 import java.util.Arrays;
  18
  19 import org.eclipse.jdt.annotation.NonNullByDefault;
  20 import org.openhab.binding.powermax.internal.message.PowermaxCommManager;
  21 import org.openhab.binding.powermax.internal.message.PowermaxReceiveType;
  22 import org.openhab.core.util.HexUtils;
  23 import org.slf4j.Logger;
  24 import org.slf4j.LoggerFactory;
  25
  26 /**
  27  * A class that reads messages from the Visonic alarm panel in a dedicated thread
  28  *
  29  * @author Laurent Garnier - Initial contribution
  30  */
  31 @NonNullByDefault
  32 public class PowermaxReaderThread extends Thread {
  33
  34     private static final int READ_BUFFER_SIZE = 20;
  35     private static final int MAX_MSG_SIZE = 0xC0;
  36
  37     private final Logger logger = LoggerFactory.getLogger(PowermaxReaderThread.class);
  38
  39     private final PowermaxConnector connector;
  40
  41     /**
  42      * Constructor
  43      *
  44      * @param in the input stream
  45      * @param connector the object that should handle the received message
  46      * @param threadName the name of the thread
  47      */
  48     public PowermaxReaderThread(PowermaxConnector connector, String threadName) {
  49         super(threadName);
  50         this.connector = connector;
  51     }
  52
  53     @Override
  54     public void run() {
  55         logger.info("Data listener started");
  56
  57         byte[] readDataBuffer = new byte[READ_BUFFER_SIZE];
  58         byte[] dataBuffer = new byte[MAX_MSG_SIZE];
  59         int index = 0;
  60         int msgLen = 0;
  61         boolean variableLen = false;
  62
  63         try {
  64             while (!Thread.interrupted()) {
  65                 int len = connector.read(readDataBuffer);
  66                 if (len > 0) {
  67                     for (int i = 0; i < len; i++) {
  68                         if (index >= MAX_MSG_SIZE) {
  69                             // too many bytes received, try to find new start
  70                             if (logger.isDebugEnabled()) {
  71                                 byte[] logData = Arrays.copyOf(dataBuffer, index);
  72                                 logger.debug("Truncating message {}", HexUtils.bytesToHex(logData));
  73                             }
  74                             index = 0;
  75                         }
  76
  77                         if (index == 0 && readDataBuffer[i] == 0x0D) {
  78                             // Preamble
  79
  80                             dataBuffer[index++] = readDataBuffer[i];
  81                         } else if (index > 0) {
  82                             dataBuffer[index++] = readDataBuffer[i];
  83
  84                             if (index == 2) {
  85                                 try {
  86                                     PowermaxReceiveType msgType = PowermaxReceiveType.fromCode(readDataBuffer[i]);
  87                                     msgLen = msgType.getLength();
  88                                     variableLen = ((readDataBuffer[i] & 0x000000FF) > 0x10) && (msgLen == 0);
  89                                 } catch (IllegalArgumentException arg0) {
  90                                     msgLen = 0;
  91                                     variableLen = false;
  92                                 }
  93                             } else if (index == 5 && variableLen) {
  94                                 msgLen = (readDataBuffer[i] & 0x000000FF) + 7;
  95                             } else if ((msgLen == 0 && readDataBuffer[i] == 0x0A) || (index == msgLen)) {
  96                                 // Postamble
  97
  98                                 if (readDataBuffer[i] != 0x0A && dataBuffer[index - 1] == 0x43) {
  99                                     // adjust message length for 0x43
 100                                     msgLen++;
 101                                 } else if (checkCRC(dataBuffer, index)) {
 102                                     // whole message received with a right CRC
 103
 104                                     byte[] msg = new byte[index];
 105                                     msg = Arrays.copyOf(dataBuffer, index);
 106
 107                                     connector.setWaitingForResponse(System.currentTimeMillis());
 108                                     connector.handleIncomingMessage(msg);
 109
 110                                     // find new preamble
 111                                     index = 0;
 112                                 } else if (msgLen == 0) {
 113                                     // CRC check failed for a message with an unknown length
 114                                     logger.debug("Message length is now {} but message is apparently not complete",
 115                                             index + 1);
 116                                 } else {
 117                                     // CRC check failed for a message with a known length
 118
 119                                     connector.setWaitingForResponse(System.currentTimeMillis());
 120
 121                                     // find new preamble
 122                                     index = 0;
 123                                 }
 124                             }
 125                         }
 126                     }
 127                 }
 128             }
 129         } catch (InterruptedIOException e) {
 130             Thread.currentThread().interrupt();
 131             logger.debug("Interrupted via InterruptedIOException");
 132         } catch (IOException e) {
 133             logger.debug("Reading failed: {}", e.getMessage(), e);
 134             connector.handleCommunicationFailure(e.getMessage());
 135         } catch (Exception e) {
 136             String msg = e.getMessage() != null ? e.getMessage() : e.toString();
 137             logger.debug("Error reading or processing message: {}", msg, e);
 138             connector.handleCommunicationFailure(msg);
 139         }
 140
 141         logger.info("Data listener stopped");
 142     }
 143
 144     /**
 145      * Check if the CRC inside a received message is valid or not
 146      *
 147      * @param data the buffer containing the message
 148      * @param len the size of the message in the buffer
 149      *
 150      * @return true if the CRC is valid or false if not
 151      */
 152     private boolean checkCRC(byte[] data, int len) {
 153         // Messages of type 0xF1 are always sent with a bad CRC (possible panel bug?)
 154         if (len == 9 && (data[1] & 0xFF) == 0xF1) {
 155             return true;
 156         }
 157
 158         byte checksum = PowermaxCommManager.computeCRC(data, len);
 159         byte expected = data[len - 2];
 160         if (checksum != expected) {
 161             byte[] logData = Arrays.copyOf(data, len);
 162             logger.warn("Powermax alarm binding: message CRC check failed (expected {}, got {}, message {})",
 163                     String.format("%02X", expected), String.format("%02X", checksum), HexUtils.bytesToHex(logData));
 164         }
 165         return (checksum == expected);
 166     }
 167 }