org.apache.mina.filter.firewall.ConnectionThrottleFilter Maven / Gradle / Ivy
/**
* Copyright 2007-2015, Kaazing Corporation. All rights reserved.
*
* Licensed 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 org.apache.mina.filter.firewall;
import java.net.InetSocketAddress;
import java.net.SocketAddress;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import org.apache.mina.core.filterchain.IoFilter;
import org.apache.mina.core.filterchain.IoFilterAdapter;
import org.apache.mina.core.session.IoSession;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* A {@link IoFilter} which blocks connections from connecting
* at a rate faster than the specified interval.
*
* @author Apache MINA Project
*/
public class ConnectionThrottleFilter extends IoFilterAdapter {
private static final long DEFAULT_TIME = 1000;
private long allowedInterval;
private final Map clients;
private final static Logger LOGGER = LoggerFactory.getLogger(ConnectionThrottleFilter.class);
/**
* Default constructor. Sets the wait time to 1 second
*/
public ConnectionThrottleFilter() {
this(DEFAULT_TIME);
}
/**
* Constructor that takes in a specified wait time.
*
* @param allowedInterval
* The number of milliseconds a client is allowed to wait
* before making another successful connection
*
*/
public ConnectionThrottleFilter(long allowedInterval) {
this.allowedInterval = allowedInterval;
clients = Collections.synchronizedMap(new HashMap());
}
/**
* Sets the interval between connections from a client.
* This value is measured in milliseconds.
*
* @param allowedInterval
* The number of milliseconds a client is allowed to wait
* before making another successful connection
*/
public void setAllowedInterval(long allowedInterval) {
this.allowedInterval = allowedInterval;
}
/**
* Method responsible for deciding if a connection is OK
* to continue
*
* @param session
* The new session that will be verified
* @return
* True if the session meets the criteria, otherwise false
*/
protected boolean isConnectionOk(IoSession session) {
SocketAddress remoteAddress = session.getRemoteAddress();
if (remoteAddress instanceof InetSocketAddress) {
InetSocketAddress addr = (InetSocketAddress) remoteAddress;
long now = System.currentTimeMillis();
if (clients.containsKey(addr.getAddress().getHostAddress())) {
LOGGER.debug("This is not a new client");
Long lastConnTime = clients.get(addr.getAddress()
.getHostAddress());
clients.put(addr.getAddress().getHostAddress(), now);
// if the interval between now and the last connection is
// less than the allowed interval, return false
if (now - lastConnTime < allowedInterval) {
LOGGER.warn("Session connection interval too short");
return false;
}
return true;
}
clients.put(addr.getAddress().getHostAddress(), now);
return true;
}
return false;
}
@Override
public void sessionCreated(NextFilter nextFilter, IoSession session)
throws Exception {
if (!isConnectionOk(session)) {
LOGGER.warn("Connections coming in too fast; closing.");
session.close(true);
}
nextFilter.sessionCreated(session);
}
}