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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.benqprojector.internal.discovery;
  14
  15 import static org.openhab.binding.benqprojector.internal.BenqProjectorBindingConstants.*;
  16
  17 import java.io.IOException;
  18 import java.net.DatagramPacket;
  19 import java.net.InetAddress;
  20 import java.net.InetSocketAddress;
  21 import java.net.InterfaceAddress;
  22 import java.net.MulticastSocket;
  23 import java.net.NetworkInterface;
  24 import java.net.SocketException;
  25 import java.net.SocketTimeoutException;
  26 import java.nio.charset.StandardCharsets;
  27 import java.util.Enumeration;
  28 import java.util.HashMap;
  29 import java.util.Locale;
  30 import java.util.Map;
  31
  32 import org.eclipse.jdt.annotation.NonNullByDefault;
  33 import org.eclipse.jdt.annotation.Nullable;
  34 import org.openhab.core.thing.Thing;
  35 import org.slf4j.Logger;
  36 import org.slf4j.LoggerFactory;
  37
  38 /**
  39  * The {@link MulticastListener} class is responsible for listening for the BenQ projector device announcement
  40  * beacons on the multicast address, and then extracting the data fields out of the received datagram.
  41  *
  42  * @author Mark Hilbush - Initial contribution
  43  * @author Michael Lobstein - Adapted for the BenQ Projector binding
  44  */
  45 @NonNullByDefault
  46 public class MulticastListener {
  47     private final Logger logger = LoggerFactory.getLogger(MulticastListener.class);
  48
  49     private MulticastSocket socket;
  50     private InetSocketAddress inetSocketAddress;
  51
  52     // BenQ projector devices announce themselves on the AMX DDD multicast port
  53     private static final String AMX_MULTICAST_GROUP = "239.255.250.250";
  54     private static final int AMX_MULTICAST_PORT = 9131;
  55
  56     // How long to wait in milliseconds for a discovery beacon
  57     public static final int DEFAULT_SOCKET_TIMEOUT_SEC = 3000;
  58
  59     /*
  60      * Constructor joins the multicast group, throws IOException on failure.
  61      */
  62     public MulticastListener(String ipv4Address) throws IOException, SocketException {
  63         InetAddress ifAddress = InetAddress.getByName(ipv4Address);
  64         NetworkInterface networkInterface = getMulticastInterface(ipv4Address);
  65         logger.debug("Discovery job using address {} on network interface {}", ifAddress.getHostAddress(),
  66                 networkInterface.getName());
  67         socket = new MulticastSocket(AMX_MULTICAST_PORT);
  68         socket.setNetworkInterface(networkInterface);
  69         socket.setSoTimeout(DEFAULT_SOCKET_TIMEOUT_SEC);
  70         inetSocketAddress = new InetSocketAddress(InetAddress.getByName(AMX_MULTICAST_GROUP), AMX_MULTICAST_PORT);
  71         socket.joinGroup(inetSocketAddress, null);
  72         logger.debug("Multicast listener joined multicast group {}:{}", AMX_MULTICAST_GROUP, AMX_MULTICAST_PORT);
  73     }
  74
  75     public void shutdown() {
  76         logger.debug("Multicast listener closing down multicast socket");
  77         try {
  78             socket.leaveGroup(inetSocketAddress, null);
  79             socket.close();
  80         } catch (IOException e) {
  81             logger.debug("Exception shutting down multicast socket: {}", e.getMessage());
  82         }
  83     }
  84
  85     /*
  86      * Wait on the multicast socket for an announcement beacon. Return null on socket timeout or error.
  87      * Otherwise, parse the beacon for information about the device and return the device properties.
  88      */
  89     public @Nullable Map<String, Object> waitForBeacon() throws IOException {
  90         byte[] bytes = new byte[600];
  91         boolean beaconFound;
  92
  93         // Wait for a device to announce itself
  94         logger.trace("Multicast listener waiting for datagram on multicast port");
  95         DatagramPacket msgPacket = new DatagramPacket(bytes, bytes.length);
  96         try {
  97             socket.receive(msgPacket);
  98             beaconFound = true;
  99             logger.trace("Multicast listener got datagram of length {} from multicast port: {}", msgPacket.getLength(),
 100                     msgPacket.toString());
 101         } catch (SocketTimeoutException e) {
 102             beaconFound = false;
 103         }
 104
 105         if (beaconFound) {
 106             // Return the device properties from the announcement beacon
 107             return parseAnnouncementBeacon(msgPacket);
 108         }
 109
 110         return null;
 111     }
 112
 113     /*
 114      * Parse the announcement beacon into the elements needed to create the thing.
 115      *
 116      * Example beacon:
 117      * AMXB<-UUID=000048746B33><-SDKClass=VideoProjector><-GUID=EPSON_EMP001><-Revision=1.0.0>
 118      */
 119     private @Nullable Map<String, Object> parseAnnouncementBeacon(DatagramPacket packet) {
 120         String beacon = (new String(packet.getData(), StandardCharsets.UTF_8)).trim();
 121         logger.trace("Multicast listener parsing announcement packet: {}", beacon);
 122
 123         if (beacon.toUpperCase(Locale.ENGLISH).contains("BENQ") && beacon.contains("VideoProjector")) {
 124             String[] parameterList = beacon.replace(">", "").split("<-");
 125
 126             for (String parameter : parameterList) {
 127                 String[] keyValue = parameter.split("=");
 128
 129                 if (keyValue.length == 2 && keyValue[0].contains("UUID") && !keyValue[1].isEmpty()) {
 130                     Map<String, Object> properties = new HashMap<>();
 131                     properties.put(Thing.PROPERTY_MAC_ADDRESS, keyValue[1]);
 132                     properties.put(THING_PROPERTY_HOST, packet.getAddress().getHostAddress());
 133                     properties.put(THING_PROPERTY_PORT, DEFAULT_PORT);
 134                     return properties;
 135                 }
 136             }
 137             logger.debug("Multicast listener doesn't know how to parse beacon: {}", beacon);
 138         }
 139         return null;
 140     }
 141
 142     private NetworkInterface getMulticastInterface(String interfaceIpAddress) throws SocketException {
 143         Enumeration<NetworkInterface> networkInterfaces = NetworkInterface.getNetworkInterfaces();
 144         NetworkInterface networkInterface;
 145         while (networkInterfaces.hasMoreElements()) {
 146             networkInterface = networkInterfaces.nextElement();
 147             if (networkInterface.isLoopback()) {
 148                 continue;
 149             }
 150             for (InterfaceAddress interfaceAddress : networkInterface.getInterfaceAddresses()) {
 151                 if (logger.isTraceEnabled()) {
 152                     logger.trace("Found interface address {} -> {}", interfaceAddress.toString(),
 153                             interfaceAddress.getAddress().toString());
 154                 }
 155                 if (interfaceAddress.getAddress().toString().endsWith("/" + interfaceIpAddress)) {
 156                     return networkInterface;
 157                 }
 158             }
 159         }
 160         throw new SocketException("Unable to get network interface for " + interfaceIpAddress);
 161     }
 162 }