| /* |
| * Copyright 2020-2023 Open Networking Foundation (ONF) and the ONF Contributors |
| * |
| * 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.opencord.aaa.impl; |
| |
| import com.google.common.collect.ImmutableMap; |
| import com.google.common.collect.Maps; |
| import org.apache.commons.lang3.tuple.Pair; |
| import org.slf4j.Logger; |
| |
| import java.util.Iterator; |
| import java.util.Map; |
| import java.util.concurrent.BlockingQueue; |
| import java.util.concurrent.ConcurrentMap; |
| import java.util.concurrent.Executors; |
| import java.util.concurrent.LinkedBlockingQueue; |
| import java.util.concurrent.ScheduledExecutorService; |
| import java.util.concurrent.ScheduledFuture; |
| import java.util.concurrent.TimeUnit; |
| |
| import static org.onlab.util.Tools.groupedThreads; |
| import static org.slf4j.LoggerFactory.getLogger; |
| |
| /** |
| * Manages allocating request identifiers and mapping them to sessions. |
| */ |
| public class IdentifierManager { |
| |
| private final Logger log = getLogger(getClass()); |
| |
| private static final int MAX_IDENTIFIER = 256; |
| |
| private BlockingQueue<Integer> freeIdNumbers; |
| |
| private ConcurrentMap<RequestIdentifier, Pair<String, Long>> idToSession; |
| |
| ScheduledFuture<?> scheduledidentifierPruner; |
| |
| // TODO read from component config |
| protected static int timeout = 10000; |
| protected static int pollTimeout = 2; |
| protected static int pruningInterval = 3; |
| |
| /** |
| * Creates and initializes a new identifier manager. |
| */ |
| public IdentifierManager() { |
| idToSession = Maps.newConcurrentMap(); |
| freeIdNumbers = new LinkedBlockingQueue<>(); |
| |
| // Starts at 2 because ids 0 and 1 are reserved for RADIUS server status requests. |
| for (int i = 2; i < MAX_IDENTIFIER; i++) { |
| freeIdNumbers.add(i); |
| } |
| |
| ScheduledExecutorService identifierPruner = Executors.newSingleThreadScheduledExecutor( |
| groupedThreads("onos/aaa", "idpruner-%d", log)); |
| |
| scheduledidentifierPruner = identifierPruner.scheduleAtFixedRate( |
| new IdentifierPruner(), 0, |
| pruningInterval, TimeUnit.SECONDS); |
| } |
| |
| /** |
| * Gets a new identifier and maps it to the given session ID. |
| * |
| * @param sessionId session this identifier is associated with |
| * @return identifier |
| */ |
| public RequestIdentifier getNewIdentifier(String sessionId) { |
| // Run this part without the lock. |
| Integer idNum; |
| try { |
| idNum = freeIdNumbers.poll(pollTimeout, TimeUnit.SECONDS); |
| } catch (InterruptedException e) { |
| // Interrupted case |
| if (log.isTraceEnabled()) { |
| log.trace("Interrupted while waiting for an id"); |
| } |
| return null; |
| } |
| // Timeout let's exit |
| if (idNum == null) { |
| if (log.isTraceEnabled()) { |
| log.trace("Timedout there are no available ids"); |
| } |
| return null; |
| } |
| // Start of the synchronized zone. Real contention happens here. |
| // This thread wants to update the session map. The release thread |
| // wants to update the session map first and then free the id. Same |
| // for the pruner. If this thread is interrupted here is not a big issue |
| // its update is not yet visible for the remaining threads: i) the |
| // release thread cannot release an id not yet taken; ii) the pruning |
| // thread cannot prune for the same reason. |
| synchronized (this) { |
| if (log.isTraceEnabled()) { |
| log.trace("Got identifier {} for session {}", idNum, sessionId); |
| } |
| |
| RequestIdentifier id = RequestIdentifier.of((byte) idNum.intValue()); |
| |
| idToSession.put(id, Pair.of(sessionId, System.currentTimeMillis())); |
| |
| return id; |
| } |
| } |
| |
| /** |
| * Gets the session ID associated with a given request ID. |
| * |
| * @param id request ID |
| * @return session ID |
| */ |
| public synchronized String getSessionId(RequestIdentifier id) { |
| //TODO this has multiple accesses |
| return idToSession.get(id) == null ? null : idToSession.get(id).getKey(); |
| } |
| |
| /** |
| * Releases a request identifier and removes session mapping. |
| * |
| * @param id request identifier to release |
| */ |
| public synchronized void releaseIdentifier(RequestIdentifier id) { |
| if (log.isTraceEnabled()) { |
| log.trace("Releasing identifier {}", id.getReadableIdentifier()); |
| } |
| |
| Pair<String, Long> session = idToSession.remove(id); |
| if (session == null) { |
| if (log.isTraceEnabled()) { |
| log.trace("Unable to released identifier {} for session null", id.getReadableIdentifier()); |
| } |
| // this id wasn't mapped to a session so is still free |
| return; |
| } |
| |
| // add id number back to set of free ids |
| freeIdNumbers.add(id.getReadableIdentifier()); |
| |
| if (log.isTraceEnabled()) { |
| log.trace("Released identifier {} for session {}", id.getReadableIdentifier(), session.getKey()); |
| } |
| } |
| |
| /** |
| * Returns true if this ID is currently taken. |
| * |
| * @param id request identifier to check |
| * @return boolean |
| */ |
| private boolean isIdentifierTaken(Integer id) { |
| return !freeIdNumbers.contains(id); |
| } |
| |
| /** |
| * Returns the count of available identifiers in a given moment. |
| * |
| * @return boolean |
| */ |
| public int getAvailableIdentifiers() { |
| return freeIdNumbers.size(); |
| } |
| |
| private synchronized void pruneIfNeeded() { |
| if (log.isTraceEnabled()) { |
| log.trace("Starting pruning cycle"); |
| } |
| // Gets an immutable copy of the ids and release the ones that exceed the timeout |
| Map<RequestIdentifier, Pair<String, Long>> idsToCheck = ImmutableMap.copyOf(idToSession); |
| // We should not modify while iterating - this is why we get a copy |
| Iterator<Map.Entry<RequestIdentifier, Pair<String, Long>>> itr = idsToCheck.entrySet().iterator(); |
| itr.forEachRemaining((entry) -> { |
| RequestIdentifier id = entry.getKey(); |
| Pair<String, Long> info = entry.getValue(); |
| long diff = System.currentTimeMillis() - info.getValue(); |
| if (diff >= timeout) { |
| if (log.isTraceEnabled()) { |
| log.trace("Identifier {} for session {} has exceeded timeout {}, releasing", |
| id.getReadableIdentifier(), info.getKey(), timeout); |
| } |
| releaseIdentifier(id); |
| } |
| }); |
| if (log.isTraceEnabled()) { |
| log.trace("End pruning cycle"); |
| } |
| } |
| |
| private class IdentifierPruner implements Runnable { |
| @Override |
| public void run() { |
| pruneIfNeeded(); |
| } |
| |
| } |
| } |