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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.bigassfan.internal.discovery;
  14
  15 import static org.openhab.binding.bigassfan.internal.BigAssFanBindingConstants.BAF_PORT;
  16
  17 import java.io.IOException;
  18 import java.net.DatagramPacket;
  19 import java.net.DatagramSocket;
  20 import java.net.InetAddress;
  21 import java.net.SocketException;
  22 import java.net.SocketTimeoutException;
  23 import java.net.UnknownHostException;
  24 import java.nio.charset.StandardCharsets;
  25
  26 import org.eclipse.jdt.annotation.NonNullByDefault;
  27 import org.eclipse.jdt.annotation.Nullable;
  28 import org.slf4j.Logger;
  29 import org.slf4j.LoggerFactory;
  30
  31 /**
  32  * The {@link DiscoveryListener} is responsible for listening on the UDP socket for fan discovery messages.
  33  *
  34  * @author Mark Hilbush - Initial contribution
  35  */
  36 @NonNullByDefault
  37 public class DiscoveryListener {
  38     private final Logger logger = LoggerFactory.getLogger(DiscoveryListener.class);
  39
  40     private static final String BCAST_ADDRESS = "255.255.255.255";
  41     private static final int SOCKET_RECEIVE_TIMEOUT = 500;
  42     private static final String POLL_MESSAGE = "<ALL;DEVICE;ID;GET>";
  43
  44     @Nullable
  45     DatagramSocket dSocket;
  46     @Nullable
  47     DatagramPacket rcvPacket;
  48     byte[] rcvBuffer = new byte[0];
  49     @Nullable
  50     InetAddress bcastAddress;
  51     byte[] bcastBuffer = new byte[0];
  52     @Nullable
  53     DatagramPacket bcastPacket;
  54
  55     BigAssFanDevice device;
  56
  57     public DiscoveryListener() throws IOException, SocketException {
  58         logger.debug("DiscoveryListener opening UDP broadcast socket");
  59         dSocket = null;
  60         device = new BigAssFanDevice();
  61         try {
  62             // Create a socket on the UDP port and get send & receive buffers
  63             DatagramSocket localDatagramSocket = new DatagramSocket(BAF_PORT);
  64             localDatagramSocket.setSoTimeout(SOCKET_RECEIVE_TIMEOUT);
  65             localDatagramSocket.setBroadcast(true);
  66             dSocket = localDatagramSocket;
  67             rcvBuffer = new byte[256];
  68             rcvPacket = new DatagramPacket(rcvBuffer, rcvBuffer.length);
  69             bcastAddress = InetAddress.getByName(BCAST_ADDRESS);
  70             bcastBuffer = POLL_MESSAGE.getBytes(StandardCharsets.US_ASCII);
  71             bcastPacket = new DatagramPacket(bcastBuffer, bcastBuffer.length, bcastAddress, BAF_PORT);
  72         } catch (UnknownHostException | SocketException | SecurityException e) {
  73             logger.warn("Unexpected exception sending poll request for fans: {}", e.getMessage(), e);
  74         }
  75     }
  76
  77     public BigAssFanDevice waitForMessage() throws IOException, SocketTimeoutException {
  78         // Wait to receive a packet
  79         DatagramPacket localPacket = rcvPacket;
  80         DatagramSocket localDatagramSocket = dSocket;
  81
  82         if (localPacket != null) {
  83             localPacket.setLength(rcvBuffer.length);
  84         }
  85
  86         if (localDatagramSocket != null && localPacket != null) {
  87             localDatagramSocket.receive(localPacket);
  88
  89             // Process the received packet
  90             device.reset();
  91
  92             String address = localPacket.getAddress().getHostAddress();
  93             device.setIpAddress(address != null ? address : "");
  94
  95             String message = (new String(rcvBuffer, 0, localPacket.getLength()));
  96             device.setDiscoveryMessage(message);
  97             logger.debug("RECEIVED packet of length {} from {}: {}", message.length(), device.getIpAddress(), message);
  98         }
  99
 100         return device;
 101     }
 102
 103     public void pollForDevices() {
 104         DatagramSocket localDatagramSocket = dSocket;
 105         if (localDatagramSocket == null) {
 106             logger.debug("Socket is null in discoveryListener.pollForDevices()");
 107             return;
 108         }
 109
 110         logger.debug("Sending poll request for fans: {}", POLL_MESSAGE);
 111         try {
 112             localDatagramSocket.send(bcastPacket);
 113         } catch (IllegalArgumentException | SecurityException | IOException e) {
 114             logger.warn("Unexpected exception while sending poll request for fans: {}", e.getMessage(), e);
 115         }
 116     }
 117
 118     public void shutdown() {
 119         logger.debug("DiscoveryListener closing socket");
 120         DatagramSocket localDatagramSocket = dSocket;
 121         if (localDatagramSocket != null) {
 122             localDatagramSocket.close();
 123             dSocket = null;
 124         }
 125     }
 126 }