Simplify filtering addresses on interfaces (#41758)

This commit is a refactoring of how we filter addresses on
interfaces. In particular, we refactor all of these methods into a
common private method. We also change the order of logic to first check
if an address matches our filter and then check if the interface is
up. This is to possibly avoid problems we are seeing where devices are
flapping up and down while we are checking for loopback addresses. We do
not expect the loopback device to flap up and down so by reversing the
logic here we avoid that problem on CI machines. Finally, we expand the
error message when this does occur so that we know which device is
flapping.

server/src/main/java/org/elasticsearch/common/network/NetworkUtils.java

@@ -22,6 +22,7 @@ package org.elasticsearch.common.network;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.Constants;
 
+import java.io.IOException;
 import java.net.Inet4Address;
 import java.net.Inet6Address;
 import java.net.InetAddress;
@@ -33,6 +34,7 @@ import java.util.Collections;
 import java.util.Comparator;
 import java.util.List;
 import java.util.Optional;
+import java.util.function.Predicate;
 
 /**
  * Utilities for network interfaces / addresses binding and publishing.
@@ -150,77 +152,53 @@ public abstract class NetworkUtils {
         return Constants.WINDOWS ? false : true;
     }
 
-    /** Returns all interface-local scope (loopback) addresses for interfaces that are up. */
-    static InetAddress[] getLoopbackAddresses() throws SocketException {
-        List<InetAddress> list = new ArrayList<>();
-        for (NetworkInterface intf : getInterfaces()) {
-            if (intf.isUp()) {
-                for (InetAddress address : Collections.list(intf.getInetAddresses())) {
-                    if (address.isLoopbackAddress()) {
-                        list.add(address);
-                    }
+    private static InetAddress[] filterAllAddresses(final Predicate<InetAddress> predicate, final String message) throws IOException {
+        final List<NetworkInterface> interfaces = getInterfaces();
+        final List<InetAddress> list = new ArrayList<>();
+        for (final NetworkInterface intf : interfaces) {
+            for (final InetAddress address : Collections.list(intf.getInetAddresses())) {
+                if (predicate.test(address) && isUp(intf)) {
+                    list.add(address);
                 }
             }
         }
         if (list.isEmpty()) {
-            throw new IllegalArgumentException("No up-and-running loopback addresses found, got " + getInterfaces());
+            throw new IllegalArgumentException(message + ", got " + interfaces);
+        }
+        return list.toArray(new InetAddress[0]);
+    }
+
+    private static boolean isUp(final NetworkInterface intf) throws IOException {
+        try {
+            return intf.isUp();
+        } catch (final SocketException e) {
+            throw new IOException("failed to check if interface [" + intf.getName() + "] is up", e);
         }
-        return list.toArray(new InetAddress[list.size()]);
+    }
+
+    /** Returns all interface-local scope (loopback) addresses for interfaces that are up. */
+    static InetAddress[] getLoopbackAddresses() throws IOException {
+        return filterAllAddresses(InetAddress::isLoopbackAddress, "no up-and-running loopback addresses found");
     }
     
     /** Returns all site-local scope (private) addresses for interfaces that are up. */
-    static InetAddress[] getSiteLocalAddresses() throws SocketException {
-        List<InetAddress> list = new ArrayList<>();
-        for (NetworkInterface intf : getInterfaces()) {
-            if (intf.isUp()) {
-                for (InetAddress address : Collections.list(intf.getInetAddresses())) {
-                    if (address.isSiteLocalAddress()) {
-                        list.add(address);
-                    }
-                }
-            }
-        }
-        if (list.isEmpty()) {
-            throw new IllegalArgumentException("No up-and-running site-local (private) addresses found, got " + getInterfaces());
-        }
-        return list.toArray(new InetAddress[list.size()]);
+    static InetAddress[] getSiteLocalAddresses() throws IOException {
+        return filterAllAddresses(InetAddress::isSiteLocalAddress, "No up-and-running site-local (private) addresses found");
     }
     
     /** Returns all global scope addresses for interfaces that are up. */
-    static InetAddress[] getGlobalAddresses() throws SocketException {
-        List<InetAddress> list = new ArrayList<>();
-        for (NetworkInterface intf : getInterfaces()) {
-            if (intf.isUp()) {
-                for (InetAddress address : Collections.list(intf.getInetAddresses())) {
-                    if (address.isLoopbackAddress() == false && 
-                        address.isSiteLocalAddress() == false &&
-                        address.isLinkLocalAddress() == false) {
-                        list.add(address);
-                    }
-                }
-            }
-        }
-        if (list.isEmpty()) {
-            throw new IllegalArgumentException("No up-and-running global-scope (public) addresses found, got " + getInterfaces());
-        }
-        return list.toArray(new InetAddress[list.size()]);
+    static InetAddress[] getGlobalAddresses() throws IOException {
+        return filterAllAddresses(
+                address -> address.isLoopbackAddress() == false
+                        && address.isSiteLocalAddress() == false
+                        && address.isLinkLocalAddress() == false,
+                "no up-and-running global-scope (public) addresses found");
     }
     
     /** Returns all addresses (any scope) for interfaces that are up. 
      *  This is only used to pick a publish address, when the user set network.host to a wildcard */
-    static InetAddress[] getAllAddresses() throws SocketException {
-        List<InetAddress> list = new ArrayList<>();
-        for (NetworkInterface intf : getInterfaces()) {
-            if (intf.isUp()) {
-                for (InetAddress address : Collections.list(intf.getInetAddresses())) {
-                    list.add(address);
-                }
-            }
-        }
-        if (list.isEmpty()) {
-            throw new IllegalArgumentException("No up-and-running addresses found, got " + getInterfaces());
-        }
-        return list.toArray(new InetAddress[list.size()]);
+    static InetAddress[] getAllAddresses() throws IOException {
+        return filterAllAddresses(address -> true, "no up-and-running addresses found");
     }
     
     /** Returns addresses for the given interface (it must be marked up) */

x-pack/plugin/core/src/main/java/org/elasticsearch/common/network/InetAddressHelper.java

@@ -5,8 +5,8 @@
  */
 package org.elasticsearch.common.network;
 
+import java.io.IOException;
 import java.net.InetAddress;
-import java.net.SocketException;
 
 /**
  * We use this class to access the package private method in NetworkUtils to resolve anyLocalAddress InetAddresses for certificate
@@ -16,7 +16,7 @@ public class InetAddressHelper {
 
     private InetAddressHelper() {}
 
-    public static InetAddress[] getAllAddresses() throws SocketException {
+    public static InetAddress[] getAllAddresses() throws IOException {
         return NetworkUtils.getAllAddresses();
     }
 

x-pack/plugin/security/cli/src/main/java/org/elasticsearch/xpack/security/cli/CertGenUtils.java

@@ -42,7 +42,6 @@ import javax.security.auth.x500.X500Principal;
 import java.io.IOException;
 import java.math.BigInteger;
 import java.net.InetAddress;
-import java.net.SocketException;
 import java.security.KeyPair;
 import java.security.KeyPairGenerator;
 import java.security.KeyStore;
@@ -268,7 +267,7 @@ public class CertGenUtils {
     /**
      * Converts the {@link InetAddress} objects into a {@link GeneralNames} object that is used to represent subject alternative names.
      */
-    public static GeneralNames getSubjectAlternativeNames(boolean resolveName, Set<InetAddress> addresses) throws SocketException {
+    public static GeneralNames getSubjectAlternativeNames(boolean resolveName, Set<InetAddress> addresses) throws IOException {
         Set<GeneralName> generalNameList = new HashSet<>();
         for (InetAddress address : addresses) {
             if (address.isAnyLocalAddress()) {