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 android.net.wifi.aware;
18
19import android.content.Context;
20import android.content.pm.PackageManager;
21import android.hardware.wifi.V1_0.Constants;
22
23/**
24 * Provides utilities for the Wifi Aware manager/service.
25 *
26 * @hide
27 */
28public class WifiAwareUtils {
29    /**
30     * Per spec: The Service Name is a UTF-8 encoded string from 1 to 255 bytes in length. The
31     * only acceptable single-byte UTF-8 symbols for a Service Name are alphanumeric values (A-Z,
32     * a-z, 0-9), the hyphen ('-'), and the period ('.'). All valid multi-byte UTF-8 characters
33     * are acceptable in a Service Name.
34     */
35    public static void validateServiceName(byte[] serviceNameData) throws IllegalArgumentException {
36        if (serviceNameData == null) {
37            throw new IllegalArgumentException("Invalid service name - null");
38        }
39
40        if (serviceNameData.length < 1 || serviceNameData.length > 255) {
41            throw new IllegalArgumentException("Invalid service name length - must be between "
42                    + "1 and 255 bytes (UTF-8 encoding)");
43        }
44
45        int index = 0;
46        while (index < serviceNameData.length) {
47            byte b = serviceNameData[index];
48            if ((b & 0x80) == 0x00) {
49                if (!((b >= '0' && b <= '9') || (b >= 'a' && b <= 'z') || (b >= 'A' && b <= 'Z')
50                        || b == '-' || b == '.')) {
51                    throw new IllegalArgumentException("Invalid service name - illegal characters,"
52                            + " allowed = (0-9, a-z,A-Z, -, .)");
53                }
54            }
55            ++index;
56        }
57    }
58
59    /**
60     * Validates that the passphrase is a non-null string of the right size (per the HAL min/max
61     * length parameters).
62     *
63     * @param passphrase Passphrase to test
64     * @return true if passphrase is valid, false if not
65     */
66    public static boolean validatePassphrase(String passphrase) {
67        if (passphrase == null
68                || passphrase.length() < Constants.NanParamSizeLimits.MIN_PASSPHRASE_LENGTH
69                || passphrase.length() > Constants.NanParamSizeLimits.MAX_PASSPHRASE_LENGTH) {
70            return false;
71        }
72
73        return true;
74    }
75
76    /**
77     * Validates that the PMK is a non-null byte array of the right size (32 bytes per spec).
78     *
79     * @param pmk PMK to test
80     * @return true if PMK is valid, false if not
81     */
82    public static boolean validatePmk(byte[] pmk) {
83        if (pmk == null || pmk.length != 32) {
84            return false;
85        }
86
87        return true;
88    }
89
90    /**
91     * Returns true if the App version is older than minVersion.
92     */
93    public static boolean isLegacyVersion(Context context, int minVersion) {
94        try {
95            if (context.getPackageManager().getApplicationInfo(context.getOpPackageName(), 0)
96                    .targetSdkVersion < minVersion) {
97                return true;
98            }
99        } catch (PackageManager.NameNotFoundException e) {
100            // In case of exception, assume known app (more strict checking)
101            // Note: This case will never happen since checkPackage is
102            // called to verify valididity before checking App's version.
103        }
104        return false;
105    }
106}
107