142 lines
6.6 KiB
Java
142 lines
6.6 KiB
Java
/*
|
|
* Copyright 2017 The Netty Project
|
|
*
|
|
* The Netty Project licenses this file to you under the Apache License,
|
|
* version 2.0 (the "License"); you may not use this file except in compliance
|
|
* with the License. You may obtain a copy of the License at:
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
|
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
|
|
* License for the specific language governing permissions and limitations
|
|
* under the License.
|
|
*/
|
|
package io.netty.resolver.dns;
|
|
|
|
import io.netty.util.internal.PlatformDependent;
|
|
import io.netty.util.internal.logging.InternalLogger;
|
|
import io.netty.util.internal.logging.InternalLoggerFactory;
|
|
|
|
import java.lang.invoke.MethodHandle;
|
|
import java.lang.invoke.MethodHandles;
|
|
import java.lang.invoke.MethodType;
|
|
import java.lang.reflect.InvocationTargetException;
|
|
import java.lang.reflect.Method;
|
|
import java.security.AccessController;
|
|
import java.security.PrivilegedAction;
|
|
import java.util.concurrent.TimeUnit;
|
|
import java.util.concurrent.atomic.AtomicLong;
|
|
|
|
/**
|
|
* Utility methods related to {@link DnsServerAddressStreamProvider}.
|
|
*/
|
|
public final class DnsServerAddressStreamProviders {
|
|
|
|
private static final InternalLogger LOGGER =
|
|
InternalLoggerFactory.getInstance(DnsServerAddressStreamProviders.class);
|
|
private static final MethodHandle STREAM_PROVIDER_CONSTRUCTOR_HANDLE;
|
|
|
|
static {
|
|
MethodHandle constructorHandle = null;
|
|
if (PlatformDependent.isOsx()) {
|
|
try {
|
|
// As MacOSDnsServerAddressStreamProvider is contained in another jar which depends on this jar
|
|
// we use reflection to use it if its on the classpath.
|
|
Object maybeProvider = AccessController.doPrivileged((PrivilegedAction<Object>) () -> {
|
|
try {
|
|
return Class.forName(
|
|
"io.netty.resolver.dns.macos.MacOSDnsServerAddressStreamProvider",
|
|
true,
|
|
DnsServerAddressStreamProviders.class.getClassLoader());
|
|
} catch (Throwable cause) {
|
|
return cause;
|
|
}
|
|
});
|
|
if (maybeProvider instanceof Class) {
|
|
@SuppressWarnings("unchecked")
|
|
Class<? extends DnsServerAddressStreamProvider> providerClass =
|
|
(Class<? extends DnsServerAddressStreamProvider>) maybeProvider;
|
|
|
|
MethodHandles.Lookup lookup = MethodHandles.lookup();
|
|
Method method = providerClass.getMethod("ensureAvailability");
|
|
method.invoke(null);
|
|
constructorHandle = lookup.findConstructor(providerClass, MethodType.methodType(void.class));
|
|
constructorHandle.invoke();
|
|
} else if (!(maybeProvider instanceof ClassNotFoundException)) {
|
|
throw (Throwable) maybeProvider;
|
|
}
|
|
} catch (Throwable cause) {
|
|
LOGGER.debug(
|
|
"Unable to use MacOSDnsServerAddressStreamProvider, fallback to system defaults", cause);
|
|
constructorHandle = null;
|
|
}
|
|
}
|
|
STREAM_PROVIDER_CONSTRUCTOR_HANDLE = constructorHandle;
|
|
}
|
|
|
|
private DnsServerAddressStreamProviders() {
|
|
}
|
|
|
|
/**
|
|
* A {@link DnsServerAddressStreamProvider} which inherits the DNS servers from your local host's configuration.
|
|
* <p>
|
|
* Note that only macOS and Linux are currently supported.
|
|
* @return A {@link DnsServerAddressStreamProvider} which inherits the DNS servers from your local host's
|
|
* configuration.
|
|
*/
|
|
public static DnsServerAddressStreamProvider platformDefault() {
|
|
if (STREAM_PROVIDER_CONSTRUCTOR_HANDLE != null) {
|
|
try {
|
|
return (DnsServerAddressStreamProvider) STREAM_PROVIDER_CONSTRUCTOR_HANDLE.invoke();
|
|
} catch (IllegalAccessException | InstantiationException | InvocationTargetException e) {
|
|
// ignore
|
|
} catch (Throwable cause) {
|
|
PlatformDependent.throwException(cause);
|
|
}
|
|
}
|
|
return unixDefault();
|
|
}
|
|
|
|
public static DnsServerAddressStreamProvider unixDefault() {
|
|
return DefaultProviderHolder.DEFAULT_DNS_SERVER_ADDRESS_STREAM_PROVIDER;
|
|
}
|
|
|
|
// We use a Holder class to only initialize DEFAULT_DNS_SERVER_ADDRESS_STREAM_PROVIDER if we really
|
|
// need it.
|
|
private static final class DefaultProviderHolder {
|
|
// We use 5 minutes which is the same as what OpenJDK is using in sun.net.dns.ResolverConfigurationImpl.
|
|
private static final long REFRESH_INTERVAL = TimeUnit.MINUTES.toNanos(5);
|
|
|
|
// TODO(scott): how is this done on Windows? This may require a JNI call to GetNetworkParams
|
|
// https://msdn.microsoft.com/en-us/library/aa365968(VS.85).aspx.
|
|
static final DnsServerAddressStreamProvider DEFAULT_DNS_SERVER_ADDRESS_STREAM_PROVIDER =
|
|
new DnsServerAddressStreamProvider() {
|
|
private volatile DnsServerAddressStreamProvider currentProvider = provider();
|
|
private final AtomicLong lastRefresh = new AtomicLong(System.nanoTime());
|
|
|
|
@Override
|
|
public DnsServerAddressStream nameServerAddressStream(String hostname) {
|
|
long last = lastRefresh.get();
|
|
DnsServerAddressStreamProvider current = currentProvider;
|
|
if (System.nanoTime() - last > REFRESH_INTERVAL) {
|
|
// This is slightly racy which means it will be possible still use the old configuration
|
|
// for a small amount of time, but that's ok.
|
|
if (lastRefresh.compareAndSet(last, System.nanoTime())) {
|
|
current = currentProvider = provider();
|
|
}
|
|
}
|
|
return current.nameServerAddressStream(hostname);
|
|
}
|
|
|
|
private DnsServerAddressStreamProvider provider() {
|
|
// If on windows just use the DefaultDnsServerAddressStreamProvider.INSTANCE as otherwise
|
|
// we will log some error which may be confusing.
|
|
return PlatformDependent.isWindows() ? DefaultDnsServerAddressStreamProvider.INSTANCE :
|
|
UnixResolverDnsServerAddressStreamProvider.parseSilently();
|
|
}
|
|
};
|
|
}
|
|
}
|