1 /*
2  * Copyright (C) 2021 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 
17 package android.net.eap;
18 
19 import static android.net.eap.EapSessionConfig.EapMethodConfig.EAP_TYPE_AKA;
20 
21 import android.annotation.NonNull;
22 import android.annotation.Nullable;
23 import android.net.ipsec.ike.IkeSessionConfiguration;
24 
25 import com.android.internal.annotations.VisibleForTesting;
26 
27 import java.util.Objects;
28 
29 /**
30  * EapAkaInfo represents data provided by the server during EAP AKA authentication
31  */
32 public final class EapAkaInfo extends EapInfo {
33     /**
34      * Re-authentication ID for next use
35      *
36      * <p>This identity encoding MUST follow the UTF-8 transformation format[RFC3629].
37      *
38      * @hide
39      */
40     private final byte[] mReauthId;
41 
42     /** @hide */
43     @VisibleForTesting
EapAkaInfo(@ullable byte[] reauthId)44     public EapAkaInfo(@Nullable byte[] reauthId) {
45         super(EAP_TYPE_AKA);
46         mReauthId = reauthId;
47     }
48 
EapAkaInfo(Builder builder)49     private EapAkaInfo(Builder builder) {
50         super(EAP_TYPE_AKA);
51         mReauthId = builder.mReauthId;
52     }
53 
54     /**
55      * Retrieves re-authentication ID from server for next use.
56      *
57      * @return re-authentication ID
58      *
59      * @see <a href="https://datatracker.ietf.org/doc/html/rfc4187#section-5">RFC 4186,
60      *     Extensible Authentication Protocol Method for 3rd Generation Authentication and
61      *     Key Agreement (EAP-AKA)</a>
62      */
63     @Nullable
getReauthId()64     public byte[] getReauthId() {
65         return mReauthId;
66     }
67 
68     /**
69      * This class can be used to incrementally construct an {@link EapAkaInfo}.
70      *
71      * <p>Except for testing, IKE library users normally do not instantiate {@link EapAkaInfo}
72      * themselves but instead get a reference via {@link IkeSessionConfiguration}
73      */
74     public static final class Builder {
75         private byte[] mReauthId;
76 
77         /**
78          * Sets the re-authentication ID for next use.
79          *
80          * @param reauthId byte[] representing the client's EAP Identity.
81          * @return Builder this, to facilitate chaining.
82          */
83         @NonNull
setReauthId(@onNull byte[] reauthId)84         public Builder setReauthId(@NonNull byte[] reauthId) {
85             Objects.requireNonNull(reauthId, "reauthId must not be null");
86             this.mReauthId = new byte[reauthId.length];
87             System.arraycopy(reauthId, 0, this.mReauthId, 0, reauthId.length);
88             return this;
89         }
90 
91         /**
92          * Constructs and returns an EapAkaInfo with the information applied to this
93          * Builder.
94          *
95          * @return the EapAkaInfo constructed by this Builder.
96          */
97         @NonNull
build()98         public EapAkaInfo build() {
99             return new EapAkaInfo(this);
100         }
101     }
102 }
103