io.netty.handler.address.DynamicAddressConnectHandler Maven / Gradle / Ivy
/*
* Copyright 2019 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:
*
* https://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.handler.address;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelOutboundHandler;
import io.netty.channel.ChannelOutboundHandlerAdapter;
import io.netty.channel.ChannelPromise;
import java.net.NetworkInterface;
import java.net.SocketAddress;
/**
* {@link ChannelOutboundHandler} implementation which allows to dynamically replace the used
* {@code remoteAddress} and / or {@code localAddress} when making a connection attempt.
*
* This can be useful to for example bind to a specific {@link NetworkInterface} based on
* the {@code remoteAddress}.
*/
public abstract class DynamicAddressConnectHandler extends ChannelOutboundHandlerAdapter {
@Override
public final void connect(ChannelHandlerContext ctx, SocketAddress remoteAddress,
SocketAddress localAddress, ChannelPromise promise) {
final SocketAddress remote;
final SocketAddress local;
try {
remote = remoteAddress(remoteAddress, localAddress);
local = localAddress(remoteAddress, localAddress);
} catch (Exception e) {
promise.setFailure(e);
return;
}
ctx.connect(remote, local, promise).addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture future) {
if (future.isSuccess()) {
// We only remove this handler from the pipeline once the connect was successful as otherwise
// the user may try to connect again.
future.channel().pipeline().remove(DynamicAddressConnectHandler.this);
}
}
});
}
/**
* Returns the local {@link SocketAddress} to use for
* {@link ChannelHandlerContext#connect(SocketAddress, SocketAddress)} based on the original {@code remoteAddress}
* and {@code localAddress}.
* By default, this method returns the given {@code localAddress}.
*/
protected SocketAddress localAddress(
@SuppressWarnings("unused") SocketAddress remoteAddress, SocketAddress localAddress) throws Exception {
return localAddress;
}
/**
* Returns the remote {@link SocketAddress} to use for
* {@link ChannelHandlerContext#connect(SocketAddress, SocketAddress)} based on the original {@code remoteAddress}
* and {@code localAddress}.
* By default, this method returns the given {@code remoteAddress}.
*/
protected SocketAddress remoteAddress(
SocketAddress remoteAddress, @SuppressWarnings("unused") SocketAddress localAddress) throws Exception {
return remoteAddress;
}
}