1 /*
2 * Copyright 2014 The Netty Project
3 *
4 * The Netty Project licenses this file to you under the Apache License,
5 * version 2.0 (the "License"); you may not use this file except in compliance
6 * with the License. You may obtain a copy of the License at:
7 *
8 * https://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13 * License for the specific language governing permissions and limitations
14 * under the License.
15 */
16 package io.netty.handler.ipfilter;
17
18 import io.netty.channel.Channel;
19 import io.netty.channel.ChannelHandler;
20 import io.netty.channel.ChannelHandlerContext;
21
22 import java.net.InetAddress;
23 import java.net.InetSocketAddress;
24 import java.util.Set;
25 import java.util.concurrent.ConcurrentHashMap;
26
27 /**
28 * This class allows one to ensure that at all times for every IP address there is at most one
29 * {@link Channel} connected to the server.
30 */
31 @ChannelHandler.Sharable
32 public class UniqueIpFilter extends AbstractRemoteAddressFilter<InetSocketAddress> {
33
34 private final Set<InetAddress> connected = ConcurrentHashMap.newKeySet();
35
36 @Override
37 protected boolean accept(ChannelHandlerContext ctx, InetSocketAddress remoteAddress) throws Exception {
38 final InetAddress remoteIp = remoteAddress.getAddress();
39 if (!connected.add(remoteIp)) {
40 return false;
41 } else {
42 ctx.channel().closeFuture().addListener(future -> connected.remove(remoteIp));
43 return true;
44 }
45 }
46 }