1 files changed, 112 insertions, 0 deletions
diff --git a/src/main/java/org/traccar/broadcast/MulticastBroadcastService.java b/src/main/java/org/traccar/broadcast/MulticastBroadcastService.java
new file mode 100644
index 000000000..1c02b319b
--- /dev/null
+++ b/src/main/java/org/traccar/broadcast/MulticastBroadcastService.java
@@ -0,0 +1,112 @@
+/*
+ * Copyright 2022 Anton Tananaev (anton@traccar.org)
+ *
+ * Licensed 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.traccar.broadcast;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.traccar.config.Config;
+import org.traccar.config.Keys;
+
+import java.io.IOException;
+import java.net.DatagramPacket;
+import java.net.DatagramSocket;
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.net.MulticastSocket;
+import java.net.NetworkInterface;
+import java.nio.charset.StandardCharsets;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+public class MulticastBroadcastService extends BaseBroadcastService {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(MulticastBroadcastService.class);
+
+    private final ObjectMapper objectMapper;
+
+    private final NetworkInterface networkInterface;
+    private final int port;
+    private final InetSocketAddress group;
+
+    private DatagramSocket publisherSocket;
+
+    private final ExecutorService service = Executors.newSingleThreadExecutor();
+    private final byte[] receiverBuffer = new byte[4096];
+
+    public MulticastBroadcastService(Config config, ObjectMapper objectMapper) throws IOException {
+        this.objectMapper = objectMapper;
+        port = config.getInteger(Keys.BROADCAST_PORT);
+        String interfaceName = config.getString(Keys.BROADCAST_INTERFACE);
+        if (interfaceName.indexOf('.') >= 0 || interfaceName.indexOf(':') >= 0) {
+            networkInterface = NetworkInterface.getByInetAddress(InetAddress.getByName(interfaceName));
+        } else {
+            networkInterface = NetworkInterface.getByName(interfaceName);
+        }
+        InetAddress address = InetAddress.getByName(config.getString(Keys.BROADCAST_ADDRESS));
+        group = new InetSocketAddress(address, port);
+    }
+
+    @Override
+    public boolean singleInstance() {
+        return false;
+    }
+
+    @Override
+    protected void sendMessage(BroadcastMessage message) {
+        try {
+            byte[] buffer = objectMapper.writeValueAsString(message).getBytes(StandardCharsets.UTF_8);
+            DatagramPacket packet = new DatagramPacket(buffer, buffer.length, group);
+            publisherSocket.send(packet);
+        } catch (IOException e) {
+            LOGGER.warn("Broadcast failed", e);
+        }
+    }
+
+    @Override
+    public void start() throws IOException {
+        service.submit(receiver);
+    }
+
+    @Override
+    public void stop() {
+        service.shutdown();
+    }
+
+    private final Runnable receiver = new Runnable() {
+        @Override
+        public void run() {
+            try (MulticastSocket socket = new MulticastSocket(port)) {
+                socket.setNetworkInterface(networkInterface);
+                socket.joinGroup(group, networkInterface);
+                publisherSocket = socket;
+                while (!service.isShutdown()) {
+                    DatagramPacket packet = new DatagramPacket(receiverBuffer, receiverBuffer.length);
+                    socket.receive(packet);
+                    if (networkInterface.inetAddresses().noneMatch(a -> a.equals(packet.getAddress()))) {
+                        String data = new String(packet.getData(), 0, packet.getLength(), StandardCharsets.UTF_8);
+                        handleMessage(objectMapper.readValue(data, BroadcastMessage.class));
+                    }
+                }
+                publisherSocket = null;
+                socket.leaveGroup(group, networkInterface);
+            } catch (IOException e) {
+                throw new RuntimeException(e);
+            }
+        }
+    };
+
+}