Implemented Option to choose default network interface

Fixes #3884

bundles/config/org.eclipse.smarthome.config.core/OSGI-INF/org.eclipse.smarthome.config.core.net.NetworkConfigOptionProvider.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<scr:component xmlns:scr="http://www.osgi.org/xmlns/scr/v1.1.0" name="org.eclipse.smarthome.config.core.net.NetworkConfigOptionProvider">
+   <service>
+      <provide interface="org.eclipse.smarthome.config.core.ConfigOptionProvider"/>
+   </service>
+   <implementation class="org.eclipse.smarthome.config.core.net.NetworkConfigOptionProvider"/>
+</scr:component>

bundles/config/org.eclipse.smarthome.config.core/src/main/java/org/eclipse/smarthome/config/core/net/NetworkConfigOptionProvider.java

@@ -0,0 +1,81 @@
+/**
+ * Copyright (c) 2014-2017 by the respective copyright holders.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.eclipse.smarthome.config.core.net;
+
+import java.net.Inet6Address;
+import java.net.InetAddress;
+import java.net.NetworkInterface;
+import java.net.SocketException;
+import java.net.URI;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Locale;
+
+import org.eclipse.smarthome.config.core.ConfigOptionProvider;
+import org.eclipse.smarthome.config.core.ParameterOption;
+import org.osgi.service.component.annotations.Component;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Provides a list of IPv4 addresses of the local machine and shows the user which interface belongs to which IP address
+ *
+ * @author Stefan Triller - initial contribution
+ *
+ */
+@Component
+public class NetworkConfigOptionProvider implements ConfigOptionProvider {
+
+    static final URI CONFIG_URI = URI.create("system:network");
+    static final String PARAM_DEFAULT_INTERFACE = "defaultInterface";
+
+    private final Logger logger = LoggerFactory.getLogger(NetworkConfigOptionProvider.class);
+
+    @Override
+    public Collection<ParameterOption> getParameterOptions(URI uri, String param, Locale locale) {
+        if (!uri.equals(CONFIG_URI)) {
+            return null;
+        }
+
+        if (param.equals(PARAM_DEFAULT_INTERFACE)) {
+            return getInterfaces();
+        }
+        return null;
+    }
+
+    private List<ParameterOption> getInterfaces() {
+        ArrayList<ParameterOption> interfaceOptions = new ArrayList<>();
+        try {
+            final Enumeration<NetworkInterface> interfaces = NetworkInterface.getNetworkInterfaces();
+            while (interfaces.hasMoreElements()) {
+                final NetworkInterface current = interfaces.nextElement();
+                if (!current.isUp() || current.isLoopback() || current.isVirtual()) {
+                    continue;
+                }
+                final Enumeration<InetAddress> addresses = current.getInetAddresses();
+                while (addresses.hasMoreElements()) {
+                    final InetAddress current_addr = addresses.nextElement();
+                    if (current_addr.isLoopbackAddress() || (current_addr instanceof Inet6Address)) {
+                        continue;
+                    }
+
+                    String ipv4Address = current_addr.getHostAddress();
+                    ParameterOption po = new ParameterOption(ipv4Address, ipv4Address + " (" + current.getName() + ")");
+                    interfaceOptions.add(po);
+                }
+            }
+            return interfaceOptions;
+        } catch (SocketException ex) {
+            logger.error("Could not retrieve network interface: {}", ex.getMessage(), ex);
+            return null;
+        }
+    }
+
+}

bundles/core/org.eclipse.smarthome.core/ESH-INF/config/networkinterface.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<config-description:config-descriptions xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xmlns:config-description="http://eclipse.org/smarthome/schemas/config-description/v1.0.0"
+	xsi:schemaLocation="http://eclipse.org/smarthome/schemas/config-description/v1.0.0
+        http://eclipse.org/smarthome/schemas/config-description-1.0.0.xsd">
+
+	<config-description uri="system:network">
+		<parameter name="defaultInterface" type="text">
+			<label>Default Interface</label>
+			<description><![CDATA[
+                 <p>The default network interface to be used.</p>
+             ]]>
+			</description>
+		</parameter>
+	</config-description>
+
+</config-description:config-descriptions>

bundles/core/org.eclipse.smarthome.core/OSGI-INF/org.eclipse.smarthome.network.xml

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<scr:component xmlns:scr="http://www.osgi.org/xmlns/scr/v1.1.0" modified="modified" name="org.eclipse.smarthome.network">
+   <property name="service.config.description.uri" value="system:network"/>
+   <property name="service.config.label" value="Network Settings"/>
+   <property name="service.config.category" value="system"/>
+   <service>
+      <provide interface="org.eclipse.smarthome.core.net.NetworkInterfaceService"/>
+   </service>
+   <implementation class="org.eclipse.smarthome.core.net.NetworkInterfaceServiceImpl"/>
+</scr:component>

bundles/core/org.eclipse.smarthome.core/src/main/java/org/eclipse/smarthome/core/net/NetworkInterfaceService.java

@@ -0,0 +1,25 @@
+/**
+ * Copyright (c) 2014-2017 by the respective copyright holders.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.eclipse.smarthome.core.net;
+
+/**
+ * Service that provides information about local network interfaces
+ *
+ * @author Stefan Triller - initial contribution
+ *
+ */
+public interface NetworkInterfaceService {
+
+    /**
+     * Obtain the local IPv4 address
+     *
+     * @return IPv4 address as string
+     */
+    String getLocalIpv4HostAddress();
+
+}

bundles/core/org.eclipse.smarthome.core/src/main/java/org/eclipse/smarthome/core/net/NetworkInterfaceServiceImpl.java

@@ -0,0 +1,53 @@
+/**
+ * Copyright (c) 2014-2017 by the respective copyright holders.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.eclipse.smarthome.core.net;
+
+import java.util.Dictionary;
+import java.util.Map;
+
+import org.osgi.service.component.ComponentContext;
+import org.osgi.service.component.annotations.Component;
+import org.osgi.service.component.annotations.Modified;
+
+/**
+ * Service that provides the current configured IPv4 address of the system
+ *
+ * @author Stefan Triller - initial contribution
+ *
+ */
+@Component(name = "org.eclipse.smarthome.network", property = { "service.config.description.uri=system:network",
+        "service.config.label=Network Settings", "service.config.category=system" })
+public class NetworkInterfaceServiceImpl implements NetworkInterfaceService {
+
+    private static final String DEFAULT_INTERFACE = "defaultInterface";
+
+    private String defaultInterface;
+
+    @SuppressWarnings("unchecked")
+    protected void activate(ComponentContext componentContext) {
+        Dictionary<String, Object> props = componentContext.getProperties();
+        modified((Map<String, Object>) props);
+    }
+
+    @Modified
+    public synchronized void modified(Map<String, Object> config) {
+        String defaultInterfaceConfig = (String) config.get(DEFAULT_INTERFACE);
+        if (defaultInterfaceConfig == null) {
+            // if none is specified we return the default one for backward compatibility
+            defaultInterface = NetUtil.getLocalIpv4HostAddress();
+        } else {
+            defaultInterface = (String) config.get(DEFAULT_INTERFACE);
+        }
+    }
+
+    @Override
+    public String getLocalIpv4HostAddress() {
+        return defaultInterface;
+    }
+
+}

docs/documentation/development/bindings/thing-handler.md

@@ -180,6 +180,27 @@ Furthermore bindings can specify a localized description of the thing status by
 rate_limit=Device is blocked by remote service for {0} minutes. Maximum limit of {1} configuration changes per {2} has been exceeded. For further info please refer to device vendor.
 ```
 
+## Offering a callback URL
+
+Some things might require a `callback` URL which should be bould to a certain network interface. A user can configure his default network interface via Paper UI under `Configuration -> System -> Network Settings`. To obtain this configured address the `ThingHandlerFactory` needs a `service reference` to the `NetworkInterfaceService` in its `OSGI-INF/MyHandlerFactory.xml`:
+
+```
+<reference bind="setNetworkInterfaceService" cardinality="1..1" interface="org.eclipse.smarthome.core.net.NetworkInterfaceService" name="NetworkInterfaceService" policy="static" unbind="unsetNetworkInterfaceService"/>
+```
+
+Inside `MyHandlerFactory.java` two methods are required:
+
+```java
+protected void setNetworkInterfaceService(NetworkInterfaceService networkInterfaceService) {
+	this.networkInterfaceService = networkInterfaceService;
+	}
+protected void unsetNetworkInterfaceService(NetworkInterfaceService networkInterfaceService) {
+	this.networkInterfaceService = null;
+}
+```
+
+Now the `MyHandlerFactory` can obtain the configured IP address via `networkInterfaceService.getLocalIpv4HostAddress()`. This IP address can be used in callback URL offered to a device.
+
 ## Channel Links
 
 Some bindings might want to start specific functionality for a channel only if an item is linked to the channel. The `ThingHandler` has two callback methods `channelLinked(ChannelUID channelUID)` and `channelUnlinked(ChannelUID channelUID)`, which are called for every link that is added or removed to/from a channel. So please be aware of the fact that both methods can be called multiple times.

extensions/binding/org.eclipse.smarthome.binding.sonos/OSGI-INF/SonosHandlerFactory.xml

@@ -18,4 +18,5 @@
       <provide interface="org.eclipse.smarthome.core.thing.binding.ThingHandlerFactory"/>
    </service>
    <reference bind="setAudioHTTPServer" cardinality="1..1" interface="org.eclipse.smarthome.core.audio.AudioHTTPServer" name="AudioHTTPServer" policy="static" unbind="unsetAudioHTTPServer"/>
+   <reference bind="setNetworkInterfaceService" cardinality="1..1" interface="org.eclipse.smarthome.core.net.NetworkInterfaceService" name="NetworkInterfaceService" policy="static" unbind="unsetNetworkInterfaceService"/>
 </scr:component>

extensions/binding/org.eclipse.smarthome.binding.sonos/src/main/java/org/eclipse/smarthome/binding/sonos/internal/SonosHandlerFactory.java

@@ -21,7 +21,7 @@
 import org.eclipse.smarthome.core.audio.AudioHTTPServer;
 import org.eclipse.smarthome.core.audio.AudioSink;
 import org.eclipse.smarthome.core.net.HttpServiceUtil;
-import org.eclipse.smarthome.core.net.NetUtil;
+import org.eclipse.smarthome.core.net.NetworkInterfaceService;
 import org.eclipse.smarthome.core.thing.Thing;
 import org.eclipse.smarthome.core.thing.ThingTypeUID;
 import org.eclipse.smarthome.core.thing.ThingUID;
@@ -46,6 +46,7 @@ public class SonosHandlerFactory extends BaseThingHandlerFactory {
     private UpnpIOService upnpIOService;
     private DiscoveryServiceRegistry discoveryServiceRegistry;
     private AudioHTTPServer audioHTTPServer;
+    private NetworkInterfaceService networkInterfaceService;
 
     private Map<String, ServiceRegistration<AudioSink>> audioSinkRegistrations = new ConcurrentHashMap<>();
 
@@ -110,7 +111,7 @@ private String createCallbackUrl() {
         if (callbackUrl != null) {
             return callbackUrl;
         } else {
-            final String ipAddress = NetUtil.getLocalIpv4HostAddress();
+            final String ipAddress = networkInterfaceService.getLocalIpv4HostAddress();
             if (ipAddress == null) {
                 logger.warn("No network interface could be found.");
                 return null;
@@ -171,4 +172,12 @@ protected void unsetAudioHTTPServer(AudioHTTPServer audioHTTPServer) {
         this.audioHTTPServer = null;
     }
 
+    protected void setNetworkInterfaceService(NetworkInterfaceService networkInterfaceService) {
+        this.networkInterfaceService = networkInterfaceService;
+    }
+
+    protected void unsetNetworkInterfaceService(NetworkInterfaceService networkInterfaceService) {
+        this.networkInterfaceService = null;
+    }
+
 }