1 /* 2 * Copyright (c) 2002, 2021, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 package java.net; 26 27 import java.io.IOException; 28 29 import static java.net.InetAddress.IPv6; 30 import static java.net.InetAddress.PREFER_IPV6_VALUE; 31 import static java.net.InetAddress.PREFER_SYSTEM_VALUE; 32 33 /* 34 * Package private implementation of InetAddressImpl for dual 35 * IPv4/IPv6 stack. 36 * <p> 37 * If InetAddress.preferIPv6Address is true then anyLocalAddress() 38 * and localHost() will return IPv6 addresses, otherwise IPv4 addresses. 39 * 40 * loopbackAddress() will return the first valid loopback address in 41 * [IPv6 loopback, IPv4 loopback] if InetAddress.preferIPv6Address is true, 42 * else [IPv4 loopback, IPv6 loopback]. 43 * If neither are valid it will fallback to the first address tried. 44 * 45 * @since 1.4 46 */ 47 final class Inet6AddressImpl implements InetAddressImpl { 48 49 public native String getLocalHostName() throws UnknownHostException; 50 51 public native InetAddress[] lookupAllHostAddr(String hostname) 52 throws UnknownHostException; 53 54 public native String getHostByAddr(byte[] addr) throws UnknownHostException; 55 56 private native boolean isReachable0(byte[] addr, int scope, int timeout, 57 byte[] inf, int ttl, int if_scope) 58 throws IOException; 59 60 public boolean isReachable(InetAddress addr, int timeout, 61 NetworkInterface netif, int ttl) 62 throws IOException 63 { 64 byte[] ifaddr = null; 65 int scope = -1; 66 int netif_scope = -1; 67 if (netif != null) { 68 /* 69 * Let's make sure we bind to an address of the proper family. 70 * Which means same family as addr because at this point it could 71 * be either an IPv6 address or an IPv4 address (case of a dual 72 * stack system). 73 */ 74 java.util.Enumeration<InetAddress> it = netif.getInetAddresses(); 75 InetAddress inetaddr; 76 while (it.hasMoreElements()) { 77 inetaddr = it.nextElement(); 78 if (inetaddr.getClass().isInstance(addr)) { 79 ifaddr = inetaddr.getAddress(); 80 if (inetaddr instanceof Inet6Address) { 81 netif_scope = ((Inet6Address) inetaddr).getScopeId(); 82 } 83 break; 84 } 85 } 86 if (ifaddr == null) { 87 // Interface doesn't support the address family of 88 // the destination 89 return false; 90 } 91 } 92 if (addr instanceof Inet6Address) 93 scope = ((Inet6Address) addr).getScopeId(); 94 return isReachable0(addr.getAddress(), scope, timeout, ifaddr, ttl, netif_scope); 95 } 96 97 public synchronized InetAddress anyLocalAddress() { 98 if (anyLocalAddress == null) { 99 if (InetAddress.preferIPv6Address == PREFER_IPV6_VALUE || 100 InetAddress.preferIPv6Address == PREFER_SYSTEM_VALUE) { 101 anyLocalAddress = new Inet6Address(); 102 anyLocalAddress.holder().hostName = "::"; 103 } else { 104 anyLocalAddress = (new Inet4AddressImpl()).anyLocalAddress(); 105 } 106 } 107 return anyLocalAddress; 108 } 109 110 public synchronized InetAddress loopbackAddress() { 111 if (loopbackAddress == null) { 112 boolean preferIPv6Address = 113 InetAddress.preferIPv6Address == PREFER_IPV6_VALUE || 114 InetAddress.preferIPv6Address == PREFER_SYSTEM_VALUE; 115 116 for (int i = 0; i < 2; i++) { 117 InetAddress address; 118 // Order the candidate addresses by preference. 119 if (i == (preferIPv6Address ? 0 : 1)) { 120 address = new Inet6Address("localhost", 121 new byte[]{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 122 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01}); 123 } else { 124 address = new Inet4Address("localhost", new byte[]{ 0x7f,0x00,0x00,0x01 }); 125 } 126 if (i == 0) { 127 // In case of failure, default to the preferred address. 128 loopbackAddress = address; 129 } 130 try { 131 if (!NetworkInterface.isBoundInetAddress(address)) { 132 continue; 133 } 134 } catch (SocketException e) { 135 continue; 136 } 137 loopbackAddress = address; 138 break; 139 } 140 } 141 return loopbackAddress; 142 } 143 144 private InetAddress anyLocalAddress; 145 private InetAddress loopbackAddress; 146 } --- EOF ---