1 /*
2  * Copyright (C) 2020 The Android Open Source Project
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 package com.android.internal.net.ipsec.ike.utils;
17 
18 import android.util.CloseGuard;
19 import android.util.Pair;
20 
21 import java.net.InetAddress;
22 import java.util.HashSet;
23 import java.util.Set;
24 
25 /**
26  * This class represents a reserved IKE SPI.
27  *
28  * <p>This class is created to avoid assigning same SPI to the same address.
29  *
30  * <p>Objects of this type are used to track reserved IKE SPI to avoid SPI collision. They can be
31  * obtained by calling {@link #allocateSecurityParameterIndex()} and must be released by calling
32  * {@link #close()} when they are no longer needed.
33  *
34  * <p>This class MUST only be called from IKE worker thread. Methods that allocate and close IKE
35  * SPI resource are not thread safe.
36  *
37  * <p>This class follows the pattern of {@link IpSecManager.SecurityParameterIndex}.
38  */
39 public final class IkeSecurityParameterIndex implements AutoCloseable {
40     // Package private Set to remember assigned IKE SPIs to avoid SPI collision. MUST be
41     // accessed only by IkeSecurityParameterIndex and IkeSpiGenerator
42     static final Set<Pair<InetAddress, Long>> sAssignedIkeSpis = new HashSet<>();
43 
44     private final InetAddress mSourceAddress;
45     private final long mSpi;
46     private final CloseGuard mCloseGuard = new CloseGuard();
47 
48     // Package private constructor that MUST only be called from IkeSpiGenerator
IkeSecurityParameterIndex(InetAddress sourceAddress, long spi)49     IkeSecurityParameterIndex(InetAddress sourceAddress, long spi) {
50         mSourceAddress = sourceAddress;
51         mSpi = spi;
52         mCloseGuard.open("close");
53     }
54 
55     /**
56      * Get the underlying SPI held by this object.
57      *
58      * @return the underlying IKE SPI.
59      */
getSpi()60     public long getSpi() {
61         return mSpi;
62     }
63 
64     /** Release an SPI that was previously reserved. */
65     @Override
close()66     public void close() {
67         sAssignedIkeSpis.remove(new Pair<InetAddress, Long>(mSourceAddress, mSpi));
68         mCloseGuard.close();
69     }
70 
71     /** Check that the IkeSecurityParameterIndex was closed properly. */
72     @Override
finalize()73     protected void finalize() throws Throwable {
74         if (mCloseGuard != null) {
75             mCloseGuard.warnIfOpen();
76         }
77         close();
78     }
79 }
80