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/*
* Copyright (c) 2002, 2010, 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
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package sun.net.dns;
import java.util.List;
import java.util.LinkedList;
import java.util.StringTokenizer;
import java.io.IOException;
import cli.System.Net.NetworkInformation.IPAddressCollection;
import cli.System.Net.NetworkInformation.IPInterfaceProperties;
import cli.System.Net.NetworkInformation.NetworkInterface;
/*
* An implementation of sun.net.ResolverConfiguration for Windows.
*/
public class ResolverConfigurationImpl
extends ResolverConfiguration
{
// Lock helds whilst loading configuration or checking
private static Object lock = new Object();
// Resolver options
private final Options opts;
// Addreses have changed
private static boolean changed = false;
// Time of last refresh.
private static long lastRefresh = -1;
// Cache timeout (120 seconds) - should be converted into property
// or configured as preference in the future.
private static final int TIMEOUT = 120000;
// DNS suffix list and name servers populated by native method
private static String os_searchlist;
private static String os_nameservers;
// Cached lists
private static LinkedList searchlist;
private static LinkedList nameservers;
// Parse string that consists of token delimited by space or commas
// and return LinkedHashMap
private LinkedList<String> stringToList(String str) {
LinkedList<String> ll = new LinkedList<>();
// comma and space are valid delimites
StringTokenizer st = new StringTokenizer(str, ", ");
while (st.hasMoreTokens()) {
String s = st.nextToken();
if (!ll.contains(s)) {
ll.add(s);
}
}
return ll;
}
// Load DNS configuration from OS
private void loadConfig() {
assert Thread.holdsLock(lock);
// if address have changed then DNS probably changed aswell;
// otherwise check if cached settings have expired.
//
if (changed) {
changed = false;
} else {
if (lastRefresh >= 0) {
long currTime = System.currentTimeMillis();
if ((currTime - lastRefresh) < TIMEOUT) {
return;
}
}
}
// load DNS configuration, update timestamp, create
// new HashMaps from the loaded configuration
//
loadDNSconfig0();
lastRefresh = System.currentTimeMillis();
searchlist = stringToList(os_searchlist);
nameservers = stringToList(os_nameservers);
os_searchlist = null; // can be GC'ed
os_nameservers = null;
}
ResolverConfigurationImpl() {
opts = new OptionsImpl();
}
public List<String> searchlist() {
synchronized (lock) {
loadConfig();
// List is mutable so return a shallow copy
return (List)searchlist.clone();
}
}
public List<String> nameservers() {
synchronized (lock) {
loadConfig();
// List is mutable so return a shallow copy
return (List)nameservers.clone();
}
}
public Options options() {
return opts;
}
// --- Address Change Listener
static class AddressChangeListener extends Thread {
public void run() {
for (;;) {
// wait for configuration to change
if (notifyAddrChange0() != 0)
return;
synchronized (lock) {
changed = true;
}
}
}
}
// --- Native methods --
static void init0() {
}
static void loadDNSconfig0() {
String searchlist = "";
String nameservers = "";
for (NetworkInterface iface : NetworkInterface.GetAllNetworkInterfaces()) {
IPInterfaceProperties props = iface.GetIPProperties();
IPAddressCollection addresses = props.get_DnsAddresses();
for (int i = 0; i < addresses.get_Count(); i++) {
cli.System.Net.IPAddress addr = addresses.get_Item(i);
// no IPv6 support
if (addr.get_AddressFamily().Value == cli.System.Net.Sockets.AddressFamily.InterNetwork) {
nameservers = strAppend(nameservers, addr.toString());
}
}
try {
if (false) throw new cli.System.PlatformNotSupportedException();
searchlist = strAppend(searchlist, props.get_DnsSuffix());
}
catch (cli.System.PlatformNotSupportedException _) {
}
}
os_searchlist = searchlist;
os_nameservers = nameservers;
}
private static String strAppend(String s, String app) {
if (s.equals("")) {
return app;
}
if (app.equals("")) {
return s;
}
return s + " " + app;
}
static int notifyAddrChange0() {
// TODO we could use System.Net.NetworkInformation.NetworkChange to detect changes
return -1;
}
static {
java.security.AccessController.doPrivileged(
new sun.security.action.LoadLibraryAction("net"));
init0();
// start the address listener thread
AddressChangeListener thr = new AddressChangeListener();
thr.setDaemon(true);
thr.start();
}
}
/**
* Implementation of {@link ResolverConfiguration.Options}
*/
class OptionsImpl extends ResolverConfiguration.Options {
}
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