1/*
2 * Copyright (C) 2016 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
17package com.android.server.wifi.hotspot2.anqp.eap;
18
19import com.android.internal.annotations.VisibleForTesting;
20
21import java.net.ProtocolException;
22import java.nio.BufferUnderflowException;
23import java.nio.ByteBuffer;
24import java.util.Collections;
25import java.util.HashMap;
26import java.util.HashSet;
27import java.util.Map;
28import java.util.Set;
29
30/**
31 * An EAP Method part of the NAI Realm ANQP element, specified in
32 * IEEE802.11-2012 section 8.4.4.10, figure 8-420
33 *
34 * Format:
35 * | Length | EAP Method | Auth Param Count | Auth Param #1 (optional) | ....
36 *     1          1               1                 variable
37 */
38public class EAPMethod {
39    private final int mEAPMethodID;
40    private final Map<Integer, Set<AuthParam>> mAuthParams;
41
42    @VisibleForTesting
43    public EAPMethod(int methodID, Map<Integer, Set<AuthParam>> authParams) {
44        mEAPMethodID = methodID;
45        mAuthParams = authParams;
46    }
47
48    /**
49     * Parse a EAPMethod from the given buffer.
50     *
51     * @param payload The byte buffer to read from
52     * @return {@link EAPMethod}
53     * @throws ProtocolException
54     * @throws BufferUnderflowException
55     */
56    public static EAPMethod parse(ByteBuffer payload) throws ProtocolException {
57        // Read and verify the length field.
58        int length = payload.get() & 0xFF;
59        if (length > payload.remaining()) {
60            throw new ProtocolException("Invalid data length: " + length);
61        }
62
63        int methodID = payload.get() & 0xFF;
64        int authCount = payload.get() & 0xFF;
65        Map<Integer, Set<AuthParam>> authParams = new HashMap<>();
66        while (authCount > 0) {
67            addAuthParam(authParams, parseAuthParam(payload));
68            authCount--;
69        }
70        return new EAPMethod(methodID, authParams);
71    }
72
73    /**
74     * Parse a AuthParam from the given buffer.
75     *
76     * Format:
77     * | Auth ID | Length | Value |
78     *      1         1    variable
79     *
80     * @param payload The byte buffer to read from
81     * @return {@link AuthParam}
82     * @throws BufferUnderflowException
83     * @throws ProtocolException
84     */
85    private static AuthParam parseAuthParam(ByteBuffer payload) throws ProtocolException {
86        int authID = payload.get() & 0xFF;
87        int length = payload.get() & 0xFF;
88        switch (authID) {
89            case AuthParam.PARAM_TYPE_EXPANDED_EAP_METHOD:
90                return ExpandedEAPMethod.parse(payload, length, false);
91            case AuthParam.PARAM_TYPE_NON_EAP_INNER_AUTH_TYPE:
92                return NonEAPInnerAuth.parse(payload, length);
93            case AuthParam.PARAM_TYPE_INNER_AUTH_EAP_METHOD_TYPE:
94                return InnerAuthEAP.parse(payload, length);
95            case AuthParam.PARAM_TYPE_EXPANDED_INNER_EAP_METHOD:
96                return ExpandedEAPMethod.parse(payload, length, true);
97            case AuthParam.PARAM_TYPE_CREDENTIAL_TYPE:
98                return CredentialType.parse(payload, length, false);
99            case AuthParam.PARAM_TYPE_TUNNELED_EAP_METHOD_CREDENTIAL_TYPE:
100                return CredentialType.parse(payload, length, true);
101            case AuthParam.PARAM_TYPE_VENDOR_SPECIFIC:
102                return VendorSpecificAuth.parse(payload, length);
103            default:
104                throw new ProtocolException("Unknow Auth Type ID: " + authID);
105        }
106    }
107
108    /**
109     * Add an AuthParam to a map of authentication parameters.  It is possible to have
110     * multiple authentication parameters for the same type.
111     *
112     * @param paramsMap The authentication parameter map to add the new parameter to
113     * @param authParam The authentication parameter to add
114     */
115    private static void addAuthParam(Map<Integer, Set<AuthParam>> paramsMap,
116            AuthParam authParam) {
117        Set<AuthParam> authParams = paramsMap.get(authParam.getAuthTypeID());
118        if (authParams == null) {
119            authParams = new HashSet<>();
120            paramsMap.put(authParam.getAuthTypeID(), authParams);
121        }
122        authParams.add(authParam);
123    }
124
125    public Map<Integer, Set<AuthParam>> getAuthParams() {
126        return Collections.unmodifiableMap(mAuthParams);
127    }
128
129    public int getEAPMethodID() {
130        return mEAPMethodID;
131    }
132
133    @Override
134    public boolean equals(Object thatObject) {
135        if (thatObject == this) {
136            return true;
137        }
138        if (!(thatObject instanceof EAPMethod)) {
139            return false;
140        }
141        EAPMethod that = (EAPMethod) thatObject;
142        return mEAPMethodID == that.mEAPMethodID && mAuthParams.equals(that.mAuthParams);
143    }
144
145    @Override
146    public int hashCode() {
147        return mEAPMethodID * 31 + mAuthParams.hashCode();
148    }
149
150    @Override
151    public String toString() {
152        return "EAPMethod{mEAPMethodID=" + mEAPMethodID + " mAuthParams=" + mAuthParams + "}";
153    }
154}
155