| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF 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 org.apache.knox.gateway.session.control; |
| |
| |
| import org.apache.knox.gateway.config.GatewayConfig; |
| |
| import java.util.Map; |
| import java.util.Set; |
| import java.util.concurrent.ConcurrentHashMap; |
| import java.util.concurrent.locks.Lock; |
| import java.util.concurrent.locks.ReentrantLock; |
| |
| public class ConcurrentSessionVerifier { |
| public static final ConcurrentSessionVerifier INSTANCE = new ConcurrentSessionVerifier(); |
| private Set<String> privilegedUsers; |
| private Set<String> nonPrivilegedUsers; |
| private int privilegedUserConcurrentSessionLimit; |
| private int nonPrivilegedUserConcurrentSessionLimit; |
| private Map<String, Integer> concurrentSessionCounter; |
| private final Lock sessionCountModifyLock = new ReentrantLock(); |
| |
| private ConcurrentSessionVerifier() { |
| } |
| |
| public static ConcurrentSessionVerifier getInstance() { |
| return INSTANCE; |
| } |
| |
| public void init(GatewayConfig config) { |
| this.privilegedUsers = config.getPrivilegedUsers(); |
| this.nonPrivilegedUsers = config.getNonPrivilegedUsers(); |
| this.privilegedUserConcurrentSessionLimit = config.getPrivilegedUsersConcurrentSessionLimit(); |
| this.nonPrivilegedUserConcurrentSessionLimit = config.getNonPrivilegedUsersConcurrentSessionLimit(); |
| this.concurrentSessionCounter = new ConcurrentHashMap<>(); |
| } |
| |
| public boolean verifySessionForUser(String username) { |
| if (!privilegedUsers.contains(username) && !nonPrivilegedUsers.contains(username)) { |
| return true; |
| } |
| |
| sessionCountModifyLock.lock(); |
| try { |
| concurrentSessionCounter.putIfAbsent(username, 0); |
| if (privilegedUserCheckLimitReached(username) || nonPrivilegedUserCheckLimitReached(username)) { |
| return false; |
| } |
| concurrentSessionCounter.compute(username, (key, value) -> value + 1); |
| } finally { |
| sessionCountModifyLock.unlock(); |
| } |
| return true; |
| } |
| |
| private boolean privilegedUserCheckLimitReached(String username) { |
| if (privilegedUserConcurrentSessionLimit < 0) { |
| return false; |
| } |
| return privilegedUsers.contains(username) && (concurrentSessionCounter.get(username) >= privilegedUserConcurrentSessionLimit); |
| } |
| |
| private boolean nonPrivilegedUserCheckLimitReached(String username) { |
| if (nonPrivilegedUserConcurrentSessionLimit < 0) { |
| return false; |
| } |
| return nonPrivilegedUsers.contains(username) && (concurrentSessionCounter.get(username) >= nonPrivilegedUserConcurrentSessionLimit); |
| } |
| |
| public void sessionEndedForUser(String username) { |
| sessionCountModifyLock.lock(); |
| try { |
| concurrentSessionCounter.computeIfPresent(username, (key, counter) -> decreaseCounter(counter)); |
| } finally { |
| sessionCountModifyLock.unlock(); |
| } |
| } |
| |
| private Integer decreaseCounter(Integer counter) { |
| counter--; |
| if (counter < 1) { |
| return null; |
| } else { |
| return counter; |
| } |
| } |
| |
| Integer getUserConcurrentSessionCount(String username) { |
| return concurrentSessionCounter.get(username); |
| } |
| } |