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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.paradoxalarm.internal.communication;
  14
  15 import java.util.Arrays;
  16
  17 import org.openhab.binding.paradoxalarm.internal.communication.crypto.EncryptionHandler;
  18 import org.openhab.binding.paradoxalarm.internal.util.ParadoxUtil;
  19 import org.slf4j.Logger;
  20 import org.slf4j.LoggerFactory;
  21
  22 /**
  23  * The {@link Response}. The response which is returned after receiving data from socket.
  24  *
  25  * @author Konstantin Polihronov - Initial contribution
  26  */
  27 public class Response implements IResponse {
  28
  29     private final Logger logger = LoggerFactory.getLogger(Response.class);
  30
  31     private IRequest request;
  32     private byte[] packetBytes;
  33     private byte[] header;
  34     private byte[] payload;
  35
  36     public Response(IRequest request, byte[] content, boolean useEncryption) {
  37         this.request = request;
  38         this.packetBytes = content;
  39         ParadoxUtil.printPacket("Rx packet", packetBytes);
  40
  41         if (useEncryption) {
  42             decrypt();
  43         }
  44         parsePacket();
  45     }
  46
  47     @Override
  48     public RequestType getType() {
  49         return request.getType();
  50     }
  51
  52     @Override
  53     public byte[] getPacketBytes() {
  54         return packetBytes;
  55     }
  56
  57     @Override
  58     public byte[] getPayload() {
  59         return payload;
  60     }
  61
  62     @Override
  63     public byte[] getHeader() {
  64         return header;
  65     }
  66
  67     @Override
  68     public IRequest getRequest() {
  69         return request;
  70     }
  71
  72     public void updatePayload(byte[] payload) {
  73         this.packetBytes = payload;
  74     }
  75
  76     private void decrypt() {
  77         byte[] payloadBytes = Arrays.copyOfRange(packetBytes, 16, packetBytes.length);
  78         logger.trace("DECRYPTING. Full packet length={}", packetBytes.length);
  79         EncryptionHandler handler = EncryptionHandler.getInstance();
  80         byte[] decrypted = handler.decrypt(payloadBytes);
  81
  82         header = Arrays.copyOfRange(packetBytes, 0, 16);
  83         payload = Arrays.copyOfRange(decrypted, 0, header[1]);
  84         packetBytes = ParadoxUtil.mergeByteArrays(header, payload);
  85         ParadoxUtil.printByteArray("Decrypted package=", packetBytes, packetBytes.length);
  86     }
  87
  88     /**
  89      * This method parses data from the IP150 module.
  90      * A panel command, e.g. 0x5
  91      * A logon sequence part is starting with 0x0, 0x1 or 0x7
  92      * We ignore invalid packets which do not match our pattern.
  93      *
  94      */
  95     private void parsePacket() {
  96         // Message too short
  97         if (packetBytes.length < 17) {
  98             logger.debug("Message length is too short. Length={}", packetBytes.length);
  99             return;
 100         }
 101
 102         byte receivedCommand = packetBytes[16];
 103         byte highNibble = ParadoxUtil.getHighNibble(receivedCommand);
 104         RequestType requestType = request.getType();
 105
 106         switch (requestType) {
 107             // For EPROM and RAM messages received command must be 0x5x
 108             case EPROM:
 109             case RAM:
 110                 if (highNibble == 0x5) {
 111                     header = Arrays.copyOfRange(packetBytes, 0, 22);
 112                     payload = Arrays.copyOfRange(packetBytes, 22, packetBytes.length - 1);
 113                     return;
 114                 }
 115                 break;
 116
 117             // For logon sequence packets there are various commands but their high nibbles should be either 0x0, 0x1 or
 118             // 0x7
 119             case LOGON_SEQUENCE:
 120                 switch (highNibble) {
 121                     case 0x0:
 122                     case 0x1:
 123                     case 0x7:
 124                         header = Arrays.copyOfRange(packetBytes, 0, 16);
 125                         payload = Arrays.copyOfRange(packetBytes, 16, packetBytes.length);
 126                         return;
 127                 }
 128                 break;
 129
 130             case PARTITION_COMMAND:
 131                 if (highNibble == 0x4) {
 132                     header = Arrays.copyOfRange(packetBytes, 0, 16);
 133                     payload = Arrays.copyOfRange(packetBytes, 16, 16 + packetBytes[1]);
 134                     logger.debug("Received a valid response for partition command");
 135                     return;
 136                 }
 137                 break;
 138
 139             case ZONE_COMMAND:
 140                 if (highNibble == 0xD) {
 141                     header = Arrays.copyOfRange(packetBytes, 0, 16);
 142                     payload = Arrays.copyOfRange(packetBytes, 16, 16 + packetBytes[1]);
 143                     logger.debug("Received a valid response for zone command");
 144                     return;
 145                 }
 146                 break;
 147         }
 148
 149         // All other cases are considered wrong results for the parser and are probably live events which cannot be
 150         // parsed currently
 151         logger.debug("Message command not expected. Received command={}", String.format("0x%08X", receivedCommand));
 152         header = null;
 153         payload = null;
 154     }
 155
 156     @Override
 157     public String toString() {
 158         return "Response [request=" + request + ", packetBytes=" + ParadoxUtil.byteArrayToString(packetBytes) + "]";
 159     }
 160 }