summaryrefslogtreecommitdiffstats
path: root/wifi/java/android/net/wifi/WifiSsid.java
blob: f8ba95dc07de68fd5bbfe6aa84acf1a85d0b2fb3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
/*
 * Copyright (C) 2012 The Android Open Source Project
 *
 * 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 android.net.wifi;

import android.os.Parcel;
import android.os.Parcelable;

import java.io.ByteArrayOutputStream;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.CoderResult;
import java.nio.charset.CodingErrorAction;
import java.util.Locale;

/**
 * Stores SSID octets and handles conversion.
 *
 * For Ascii encoded string, any octet < 32 or > 127 is encoded as
 * a "\x" followed by the hex representation of the octet.
 * Exception chars are ", \, \e, \n, \r, \t which are escaped by a \
 * See src/utils/common.c for the implementation in the supplicant.
 *
 * @hide
 */
public class WifiSsid implements Parcelable {
    private static final String TAG = "WifiSsid";

    public final ByteArrayOutputStream octets = new ByteArrayOutputStream(32);

    private static final int HEX_RADIX = 16;
    public static final String NONE = "<unknown ssid>";

    private WifiSsid() {
    }

    public static WifiSsid createFromAsciiEncoded(String asciiEncoded) {
        WifiSsid a = new WifiSsid();
        a.convertToBytes(asciiEncoded);
        return a;
    }

    public static WifiSsid createFromHex(String hexStr) {
        WifiSsid a = new WifiSsid();
        if (hexStr == null) return a;

        if (hexStr.startsWith("0x") || hexStr.startsWith("0X")) {
            hexStr = hexStr.substring(2);
        }

        for (int i = 0; i < hexStr.length()-1; i += 2) {
            int val;
            try {
                val = Integer.parseInt(hexStr.substring(i, i + 2), HEX_RADIX);
            } catch(NumberFormatException e) {
                val = 0;
            }
            a.octets.write(val);
        }
        return a;
    }

    /* This function is equivalent to printf_decode() at src/utils/common.c in
     * the supplicant */
    private void convertToBytes(String asciiEncoded) {
        int i = 0;
        int val = 0;
        while (i< asciiEncoded.length()) {
            char c = asciiEncoded.charAt(i);
            switch (c) {
                case '\\':
                    i++;
                    switch(asciiEncoded.charAt(i)) {
                        case '\\':
                            octets.write('\\');
                            i++;
                            break;
                        case '"':
                            octets.write('"');
                            i++;
                            break;
                        case 'n':
                            octets.write('\n');
                            i++;
                            break;
                        case 'r':
                            octets.write('\r');
                            i++;
                            break;
                        case 't':
                            octets.write('\t');
                            i++;
                            break;
                        case 'e':
                            octets.write(27); //escape char
                            i++;
                            break;
                        case 'x':
                            i++;
                            try {
                                val = Integer.parseInt(asciiEncoded.substring(i, i + 2), HEX_RADIX);
                            } catch (NumberFormatException e) {
                                val = -1;
                            }
                            if (val < 0) {
                                val = Character.digit(asciiEncoded.charAt(i), HEX_RADIX);
                                if (val < 0) break;
                                octets.write(val);
                                i++;
                            } else {
                                octets.write(val);
                                i += 2;
                            }
                            break;
                        case '0':
                        case '1':
                        case '2':
                        case '3':
                        case '4':
                        case '5':
                        case '6':
                        case '7':
                            val = asciiEncoded.charAt(i) - '0';
                            i++;
                            if (asciiEncoded.charAt(i) >= '0' && asciiEncoded.charAt(i) <= '7') {
                                val = val * 8 + asciiEncoded.charAt(i) - '0';
                                i++;
                            }
                            if (asciiEncoded.charAt(i) >= '0' && asciiEncoded.charAt(i) <= '7') {
                                val = val * 8 + asciiEncoded.charAt(i) - '0';
                                i++;
                            }
                            octets.write(val);
                            break;
                        default:
                            break;
                    }
                    break;
                default:
                    octets.write(c);
                    i++;
                    break;
            }
        }
    }

    @Override
    public String toString() {
        byte[] ssidBytes = octets.toByteArray();
        // Supplicant returns \x00\x00\x00\x00\x00\x00\x00\x00 hex string
        // for a hidden access point. Make sure we maintain the previous
        // behavior of returning empty string for this case.
        if (octets.size() <= 0 || isArrayAllZeroes(ssidBytes)) return "";
        // TODO: Handle conversion to other charsets upon failure
        Charset charset = Charset.forName("UTF-8");
        CharsetDecoder decoder = charset.newDecoder()
                .onMalformedInput(CodingErrorAction.REPLACE)
                .onUnmappableCharacter(CodingErrorAction.REPLACE);
        CharBuffer out = CharBuffer.allocate(32);

        CoderResult result = decoder.decode(ByteBuffer.wrap(ssidBytes), out, true);
        out.flip();
        if (result.isError()) {
            return NONE;
        }
        return out.toString();
    }

    private boolean isArrayAllZeroes(byte[] ssidBytes) {
        for (int i = 0; i< ssidBytes.length; i++) {
            if (ssidBytes[i] != 0) return false;
        }
        return true;
    }

    /** @hide */
    public boolean isHidden() {
        return isArrayAllZeroes(octets.toByteArray());
    }

    /** @hide */
    public byte[] getOctets() {
        return octets.toByteArray();
    }

    /** @hide */
    public String getHexString() {
        String out = "0x";
        byte[] ssidbytes = getOctets();
        for (int i = 0; i < octets.size(); i++) {
            out += String.format(Locale.US, "%02x", ssidbytes[i]);
        }
        return out;
    }

    /** Implement the Parcelable interface {@hide} */
    public int describeContents() {
        return 0;
    }

    /** Implement the Parcelable interface {@hide} */
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeInt(octets.size());
        dest.writeByteArray(octets.toByteArray());
    }

    /** Implement the Parcelable interface {@hide} */
    public static final Creator<WifiSsid> CREATOR =
        new Creator<WifiSsid>() {
            public WifiSsid createFromParcel(Parcel in) {
                WifiSsid ssid = new WifiSsid();
                int length = in.readInt();
                byte b[] = new byte[length];
                in.readByteArray(b);
                ssid.octets.write(b, 0, length);
                return ssid;
            }

            public WifiSsid[] newArray(int size) {
                return new WifiSsid[size];
            }
        };
}