8244202: Implementation of JEP 418: Internet-Address Resolution SPI

Co-authored-by: Chris Hegarty <chegar@openjdk.org>
Co-authored-by: Daniel Fuchs <dfuchs@openjdk.org>
Co-authored-by: Alan Bateman <alanb@openjdk.org>
Reviewed-by: dfuchs, alanb, michaelm, chegar

Author: 4 people

src/java.base/share/classes/java/lang/RuntimePermission.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2021, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -378,6 +378,16 @@
  *   {@linkplain ModuleFinder#ofSystem system modules} in the runtime image.</td>
  * </tr>
  *
+ * <tr>
+ *   <th scope="row">inetAddressResolverProvider</th>
+ *   <td>This {@code RuntimePermission} is required to be granted to
+ *   classes which subclass and implement {@code java.net.spi.InetAddressResolverProvider}.
+ *   The permission is checked during invocation of the abstract base class constructor.
+ *   This permission ensures trust in classes which provide resolvers used by
+ *   {@link java.net.InetAddress} hostname and address resolution methods.</td>
+ *   <td>See {@link java.net.spi.InetAddressResolverProvider} for more information.</td>
+ * </tr>
+ *
  * </tbody>
  * </table>
  *

src/java.base/share/classes/java/net/Inet4AddressImpl.java

@@ -24,6 +24,9 @@
  */
 package java.net;
 import java.io.IOException;
+import java.net.spi.InetAddressResolver.LookupPolicy;
+
+import static java.net.spi.InetAddressResolver.LookupPolicy.IPV4;
 
 /*
  * Package private implementation of InetAddressImpl for IPv4.
@@ -32,8 +35,14 @@
  */
 final class Inet4AddressImpl implements InetAddressImpl {
     public native String getLocalHostName() throws UnknownHostException;
-    public native InetAddress[]
-        lookupAllHostAddr(String hostname) throws UnknownHostException;
+    public InetAddress[] lookupAllHostAddr(String hostname, LookupPolicy lookupPolicy)
+            throws UnknownHostException {
+        if ((lookupPolicy.characteristics() & IPV4) == 0) {
+            throw new UnknownHostException(hostname);
+        }
+        return lookupAllHostAddr(hostname);
+    }
+    private native InetAddress[] lookupAllHostAddr(String hostname) throws UnknownHostException;
     public native String getHostByAddr(byte[] addr) throws UnknownHostException;
     private native boolean isReachable0(byte[] addr, int timeout, byte[] ifaddr, int ttl) throws IOException;
 

src/java.base/share/classes/java/net/Inet6AddressImpl.java

@@ -25,10 +25,9 @@
 package java.net;
 
 import java.io.IOException;
+import java.net.spi.InetAddressResolver.LookupPolicy;
 
-import static java.net.InetAddress.IPv6;
-import static java.net.InetAddress.PREFER_IPV6_VALUE;
-import static java.net.InetAddress.PREFER_SYSTEM_VALUE;
+import static java.net.InetAddress.PLATFORM_LOOKUP_POLICY;
 
 /*
  * Package private implementation of InetAddressImpl for dual
@@ -48,8 +47,13 @@ final class Inet6AddressImpl implements InetAddressImpl {
 
     public native String getLocalHostName() throws UnknownHostException;
 
-    public native InetAddress[] lookupAllHostAddr(String hostname)
-        throws UnknownHostException;
+    public InetAddress[] lookupAllHostAddr(String hostname, LookupPolicy lookupPolicy)
+            throws UnknownHostException {
+        return lookupAllHostAddr(hostname, lookupPolicy.characteristics());
+    }
+
+    private native InetAddress[] lookupAllHostAddr(String hostname, int characteristics)
+            throws UnknownHostException;
 
     public native String getHostByAddr(byte[] addr) throws UnknownHostException;
 
@@ -96,8 +100,9 @@ public boolean isReachable(InetAddress addr, int timeout,
 
     public synchronized InetAddress anyLocalAddress() {
         if (anyLocalAddress == null) {
-            if (InetAddress.preferIPv6Address == PREFER_IPV6_VALUE ||
-                InetAddress.preferIPv6Address == PREFER_SYSTEM_VALUE) {
+            int flags = PLATFORM_LOOKUP_POLICY.characteristics();
+            if (InetAddress.ipv6AddressesFirst(flags) ||
+                InetAddress.systemAddressesOrder(flags)) {
                 anyLocalAddress = new Inet6Address();
                 anyLocalAddress.holder().hostName = "::";
             } else {
@@ -109,9 +114,9 @@ public synchronized InetAddress anyLocalAddress() {
 
     public synchronized InetAddress loopbackAddress() {
         if (loopbackAddress == null) {
-            boolean preferIPv6Address =
-                InetAddress.preferIPv6Address == PREFER_IPV6_VALUE ||
-                InetAddress.preferIPv6Address == PREFER_SYSTEM_VALUE;
+            int flags = PLATFORM_LOOKUP_POLICY.characteristics();
+            boolean preferIPv6Address = InetAddress.ipv6AddressesFirst(flags) ||
+                    InetAddress.systemAddressesOrder(flags);
 
             for (int i = 0; i < 2; i++) {
                 InetAddress address;