Jonathan Hart | 612651f | 2019-11-25 09:21:43 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2020-present Open Networking Foundation |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://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, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package org.opencord.aaa.impl; |
| 18 | |
| 19 | import com.google.common.collect.Maps; |
| 20 | |
| 21 | import java.util.concurrent.BlockingQueue; |
| 22 | import java.util.concurrent.ConcurrentMap; |
| 23 | import java.util.concurrent.LinkedBlockingQueue; |
| 24 | |
| 25 | /** |
| 26 | * Manages allocating request identifiers and mapping them to sessions. |
| 27 | */ |
| 28 | public class IdentifierManager { |
| 29 | |
| 30 | private static final int MAX_IDENTIFIER = 256; |
| 31 | |
| 32 | private BlockingQueue<Integer> freeIdNumbers; |
| 33 | |
| 34 | private ConcurrentMap<RequestIdentifier, String> idToSession; |
| 35 | |
| 36 | /** |
| 37 | * Creates and initializes a new identifier manager. |
| 38 | */ |
| 39 | public IdentifierManager() { |
| 40 | idToSession = Maps.newConcurrentMap(); |
| 41 | freeIdNumbers = new LinkedBlockingQueue<>(); |
| 42 | |
| 43 | // Starts at 2 because ids 0 and 1 are reserved for RADIUS server status requests. |
| 44 | for (int i = 2; i < MAX_IDENTIFIER; i++) { |
| 45 | freeIdNumbers.add(i); |
| 46 | } |
| 47 | } |
| 48 | |
| 49 | /** |
| 50 | * Gets a new identifier and maps it to the given session ID. |
| 51 | * |
| 52 | * @param sessionId session this identifier is associated with |
| 53 | * @return identifier |
| 54 | */ |
| 55 | public synchronized RequestIdentifier getNewIdentifier(String sessionId) { |
| 56 | int idNum; |
| 57 | try { |
| 58 | idNum = freeIdNumbers.take(); |
| 59 | } catch (InterruptedException e) { |
| 60 | return null; |
| 61 | } |
| 62 | |
| 63 | RequestIdentifier id = RequestIdentifier.of((byte) idNum); |
| 64 | |
| 65 | idToSession.put(id, sessionId); |
| 66 | |
| 67 | return id; |
| 68 | } |
| 69 | |
| 70 | /** |
| 71 | * Gets the session ID associated with a given request ID. |
| 72 | * |
| 73 | * @param id request ID |
| 74 | * @return session ID |
| 75 | */ |
| 76 | public String getSessionId(RequestIdentifier id) { |
| 77 | return idToSession.get(id); |
| 78 | } |
| 79 | |
| 80 | /** |
| 81 | * Releases a request identifier and removes session mapping. |
| 82 | * |
| 83 | * @param id request identifier to release |
| 84 | */ |
| 85 | public synchronized void releaseIdentifier(RequestIdentifier id) { |
| 86 | String session = idToSession.remove(id); |
| 87 | if (session == null) { |
| 88 | // this id wasn't mapped to a session so is still free |
| 89 | return; |
| 90 | } |
| 91 | |
| 92 | // add id number back to set of free ids |
| 93 | freeIdNumbers.add((int) id.identifier()); |
| 94 | } |
| 95 | } |