fix: make local IP address detection support IPv6

Author: cortlepp

modules/kernel/src/org/apache/axis2/util/Utils.java

@@ -64,13 +64,16 @@
 import java.net.InetAddress;
 import java.net.NetworkInterface;
 import java.net.SocketException;
+import java.net.UnknownHostException;
 import java.security.AccessController;
 import java.security.PrivilegedAction;
 import java.security.PrivilegedExceptionAction;
 import java.util.Enumeration;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.Map;
+import java.util.List;
+import java.util.ArrayList;
 
 public class Utils {
     private static final Log log = LogFactory.getLog(Utils.class);
@@ -569,6 +572,86 @@ public static int getMtomThreshold(MessageContext msgCtxt){
         }
         return threshold;
     }
+    /**
+     * Returns all <code>InetAddress</code> objects encapsulating what are most likely the machine's
+     * LAN IP addresses. This method was copied from apache-commons-jcs HostNameUtil.java.
+     * <p>
+     * This method will scan all IP addresses on all network interfaces on the host machine to
+     * determine the IP addresses most likely to be the machine's LAN addresses.
+     * <p>
+     * @return List<InetAddress>
+     * @throws IllegalStateException If the LAN address of the machine cannot be found.
+     */
+    public static List<InetAddress> getLocalHostLANAddresses() throws SocketException
+    {
+        final List<InetAddress> addresses = new ArrayList<>();
+
+        try
+        {
+            InetAddress candidateAddress = null;
+            // Iterate all NICs (network interface cards)...
+            final Enumeration<NetworkInterface> ifaces = NetworkInterface.getNetworkInterfaces();
+            while ( ifaces.hasMoreElements() )
+            {
+                final NetworkInterface iface = ifaces.nextElement();
+
+                // Skip loopback interfaces
+                if (iface.isLoopback() || !iface.isUp())
+                {
+                    continue;
+                }
+
+                // Iterate all IP addresses assigned to each card...
+                for ( final Enumeration<InetAddress> inetAddrs = iface.getInetAddresses(); inetAddrs.hasMoreElements(); )
+                {
+                    final InetAddress inetAddr = inetAddrs.nextElement();
+                    if ( !inetAddr.isLoopbackAddress() )
+                    {
+                        if (inetAddr.isSiteLocalAddress())
+                        {
+                            // Found non-loopback site-local address.
+                            addresses.add(inetAddr);
+                        }
+                        if ( candidateAddress == null )
+                        {
+                            // Found non-loopback address, but not necessarily site-local.
+                            // Store it as a candidate to be returned if site-local address is not subsequently found...
+                            candidateAddress = inetAddr;
+                            // Note that we don't repeatedly assign non-loopback non-site-local addresses as candidates,
+                            // only the first. For subsequent iterations, candidate will be non-null.
+                        }
+                    }
+                }
+            }
+            if (candidateAddress != null && addresses.isEmpty())
+            {
+                // We did not find a site-local address, but we found some other non-loopback address.
+                // Server might have a non-site-local address assigned to its NIC (or it might be running
+                // IPv6 which deprecates the "site-local" concept).
+                addresses.add(candidateAddress);
+            }
+            // At this point, we did not find a non-loopback address.
+            // Fall back to returning whatever InetAddress.getLocalHost() returns...
+            if (addresses.isEmpty())
+            {
+                final InetAddress jdkSuppliedAddress = InetAddress.getLocalHost();
+                if ( jdkSuppliedAddress == null )
+                {
+                    throw new IllegalStateException( "The JDK InetAddress.getLocalHost() method unexpectedly returned null." );
+                }
+                addresses.add(jdkSuppliedAddress);
+            }
+        }
+        catch (UnknownHostException e )
+        {
+            var throwable = new SocketException("Failed to determine LAN address");
+            throwable.initCause(e);
+            throw throwable;
+        }
+
+        return addresses;
+    }
+
      /**
      * Returns the ip address to be used for the replyto epr
      * CAUTION:
@@ -582,25 +665,9 @@ public static int getMtomThreshold(MessageContext msgCtxt){
      * - Obtain the ip to be used here from the Call API
      *
      * @return Returns String.
-     * @throws java.net.SocketException
       */
     public static String getIpAddress() throws SocketException {
-        Enumeration e = NetworkInterface.getNetworkInterfaces();
-        String address = "127.0.0.1";
-
-        while (e.hasMoreElements()) {
-            NetworkInterface netface = (NetworkInterface) e.nextElement();
-            Enumeration addresses = netface.getInetAddresses();
-
-            while (addresses.hasMoreElements()) {
-                InetAddress ip = (InetAddress) addresses.nextElement();
-                if (!ip.isLoopbackAddress() && isIP(ip.getHostAddress())) {
-                    return ip.getHostAddress();
-                }
-            }
-        }
-
-        return address;
+        return getLocalHostLANAddresses().stream().findFirst().map(InetAddress::toString).orElse("127.0.0.1");
     }
 
     /**
@@ -639,10 +706,6 @@ public static String getHostname(AxisConfiguration axisConfiguration) {
         return null;
     }
 
-    private static boolean isIP(String hostAddress) {
-        return hostAddress.split("[.]").length == 4;
-    }
-
     /**
      * Get the scheme part from a URI (or URL).
      *