1 /* 2 * Copyright (C) 2019 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 com.android.server.wifi; 18 19 import android.app.compat.CompatChanges; 20 import android.content.Context; 21 import android.net.MacAddress; 22 import android.net.wifi.SoftApConfiguration; 23 import android.net.wifi.WifiConfiguration; 24 import android.net.wifi.WifiMigration; 25 import android.util.BackupUtils; 26 import android.util.Log; 27 import android.util.SparseIntArray; 28 import android.util.Xml; 29 30 import com.android.internal.util.FastXmlSerializer; 31 import com.android.modules.utils.build.SdkLevel; 32 import com.android.server.wifi.util.ApConfigUtil; 33 import com.android.server.wifi.util.SettingsMigrationDataHolder; 34 import com.android.server.wifi.util.XmlUtil; 35 36 import org.xmlpull.v1.XmlPullParser; 37 import org.xmlpull.v1.XmlPullParserException; 38 import org.xmlpull.v1.XmlSerializer; 39 40 import java.io.ByteArrayInputStream; 41 import java.io.ByteArrayOutputStream; 42 import java.io.DataInputStream; 43 import java.io.DataOutputStream; 44 import java.io.IOException; 45 import java.nio.charset.StandardCharsets; 46 import java.util.ArrayList; 47 import java.util.Iterator; 48 import java.util.List; 49 50 /** 51 * Class used to backup/restore data using the SettingsBackupAgent. 52 * There are 2 symmetric API's exposed here: 53 * 1. retrieveBackupDataFromSoftApConfiguration: Retrieve the configuration data to be backed up. 54 * 2. retrieveSoftApConfigurationFromBackupData: Restore the configuration using the provided data. 55 * The byte stream to be backed up is versioned to migrate the data easily across 56 * revisions. 57 */ 58 public class SoftApBackupRestore { 59 private static final String TAG = "SoftApBackupRestore"; 60 61 /** 62 * Current backup data version. 63 */ 64 // Starting from SoftAp data backup version 9, framework support to back up configuration 65 // in XML format. This allows to restore the SoftAp configuration when the user downgrades 66 // the Android version. (From Any version >= 9 to version#9) 67 private static final int SUPPORTED_SAP_BACKUP_XML_DATA_VERSION = 9; 68 private static final int LAST_SAP_BACKUP_DATA_VERSION_IN_S = 8; 69 private static final int LAST_SAP_BACKUP_DATA_VERSION_IN_R = 7; 70 private static final String XML_TAG_DOCUMENT_HEADER = "SoftApBackupData"; 71 72 73 private static final int ETHER_ADDR_LEN = 6; // Byte array size of MacAddress 74 75 private final Context mContext; 76 private final SettingsMigrationDataHolder mSettingsMigrationDataHolder; 77 SoftApBackupRestore(Context context, SettingsMigrationDataHolder settingsMigrationDataHolder)78 public SoftApBackupRestore(Context context, 79 SettingsMigrationDataHolder settingsMigrationDataHolder) { 80 mContext = context; 81 mSettingsMigrationDataHolder = settingsMigrationDataHolder; 82 } 83 84 /** 85 * Retrieve a byte stream representing the data that needs to be backed up from the 86 * provided softap configuration. 87 * 88 * @param config saved soft ap config that needs to be backed up. 89 * @return Raw byte stream that needs to be backed up. 90 */ retrieveBackupDataFromSoftApConfiguration(SoftApConfiguration config)91 public byte[] retrieveBackupDataFromSoftApConfiguration(SoftApConfiguration config) { 92 if (config == null) { 93 Log.e(TAG, "Invalid configuration received"); 94 return new byte[0]; 95 } 96 try { 97 final ByteArrayOutputStream baos = new ByteArrayOutputStream(); 98 final DataOutputStream out = new DataOutputStream(baos); 99 if (SdkLevel.isAtLeastT()) { 100 out.writeInt(SUPPORTED_SAP_BACKUP_XML_DATA_VERSION); 101 final XmlSerializer xmlOut = new FastXmlSerializer(); 102 xmlOut.setOutput(baos, StandardCharsets.UTF_8.name()); 103 XmlUtil.writeDocumentStart(xmlOut, XML_TAG_DOCUMENT_HEADER); 104 105 // Start writing the XML stream. 106 XmlUtil.SoftApConfigurationXmlUtil.writeSoftApConfigurationToXml(xmlOut, config, 107 null); 108 109 XmlUtil.writeDocumentEnd(xmlOut, XML_TAG_DOCUMENT_HEADER); 110 111 } else { 112 if (SdkLevel.isAtLeastS()) { 113 out.writeInt(LAST_SAP_BACKUP_DATA_VERSION_IN_S); 114 } else { 115 out.writeInt(LAST_SAP_BACKUP_DATA_VERSION_IN_R); 116 } 117 BackupUtils.writeString(out, config.getSsid()); 118 out.writeInt(config.getBand()); 119 out.writeInt(config.getChannel()); 120 BackupUtils.writeString(out, config.getPassphrase()); 121 out.writeInt(config.getSecurityType()); 122 out.writeBoolean(config.isHiddenSsid()); 123 out.writeInt(config.getMaxNumberOfClients()); 124 out.writeLong(config.getShutdownTimeoutMillis()); 125 out.writeBoolean(config.isClientControlByUserEnabled()); 126 writeMacAddressList(out, config.getBlockedClientList()); 127 writeMacAddressList(out, config.getAllowedClientList()); 128 out.writeBoolean(config.isAutoShutdownEnabled()); 129 if (SdkLevel.isAtLeastS()) { 130 out.writeBoolean(config.isBridgedModeOpportunisticShutdownEnabled()); 131 out.writeInt(config.getMacRandomizationSetting()); 132 SparseIntArray channels = config.getChannels(); 133 int numOfChannels = channels.size(); 134 out.writeInt(numOfChannels); 135 for (int i = 0; i < numOfChannels; i++) { 136 out.writeInt(channels.keyAt(i)); 137 out.writeInt(channels.valueAt(i)); 138 } 139 out.writeBoolean(config.isIeee80211axEnabled()); 140 } 141 } 142 return baos.toByteArray(); 143 } catch (IOException | XmlPullParserException e) { 144 Log.e(TAG, "Error retrieving the backup data from SoftApConfiguration: " + config 145 + ", exception " + e); 146 } 147 return new byte[0]; 148 } 149 150 /** 151 * Parse out the configurations from the back up data. 152 * 153 * @param data raw byte stream representing the data. 154 * @return Soft ap config retrieved from the backed up data. 155 */ retrieveSoftApConfigurationFromBackupData(byte[] data)156 public SoftApConfiguration retrieveSoftApConfigurationFromBackupData(byte[] data) { 157 if (data == null || data.length == 0) { 158 Log.e(TAG, "Invalid backup data received"); 159 return null; 160 } 161 SoftApConfiguration.Builder configBuilder = new SoftApConfiguration.Builder(); 162 try { 163 DataInputStream in = new DataInputStream(new ByteArrayInputStream(data)); 164 int version = in.readInt(); 165 // Starting from T, frameworks support to downgrade restore configuration. 166 if ((!SdkLevel.isAtLeastT() && version > LAST_SAP_BACKUP_DATA_VERSION_IN_S) 167 || version < 1) { 168 throw new BackupUtils.BadVersionException("Unknown Backup Serialization Version"); 169 } 170 171 if (version == 1) return null; // Version 1 is a bad dataset. 172 Log.i(TAG, "The backed-up version is " + version); 173 174 if (version >= SUPPORTED_SAP_BACKUP_XML_DATA_VERSION) { 175 final XmlPullParser xmlIn = Xml.newPullParser(); 176 ByteArrayInputStream inputStream = new ByteArrayInputStream(data); 177 // The first 4 bytes are designed to store version 178 inputStream.skip(Integer.BYTES); 179 xmlIn.setInput(inputStream, StandardCharsets.UTF_8.name()); 180 XmlUtil.gotoDocumentStart(xmlIn, XML_TAG_DOCUMENT_HEADER); 181 int rootTagDepth = xmlIn.getDepth(); 182 return XmlUtil.SoftApConfigurationXmlUtil 183 .parseFromXml(xmlIn, rootTagDepth, mSettingsMigrationDataHolder, false, 184 null); 185 } 186 configBuilder.setSsid(BackupUtils.readString(in)); 187 188 int band; 189 if (version < 4) { 190 band = ApConfigUtil.convertWifiConfigBandToSoftApConfigBand(in.readInt()); 191 } else { 192 band = in.readInt(); 193 } 194 int channel = in.readInt(); 195 if (channel == 0) { 196 configBuilder.setBand(band); 197 } else { 198 configBuilder.setChannel(channel, band); 199 } 200 String passphrase = BackupUtils.readString(in); 201 int securityType = in.readInt(); 202 if (version < 4 && securityType == WifiConfiguration.KeyMgmt.WPA2_PSK) { 203 configBuilder.setPassphrase(passphrase, SoftApConfiguration.SECURITY_TYPE_WPA2_PSK); 204 } else if (version >= 4 && securityType != SoftApConfiguration.SECURITY_TYPE_OPEN) { 205 configBuilder.setPassphrase(passphrase, securityType); 206 } 207 if (version >= 3) { 208 configBuilder.setHiddenSsid(in.readBoolean()); 209 } 210 if (version >= 5) { 211 configBuilder.setMaxNumberOfClients(in.readInt()); 212 long shutDownMillis; 213 if (version >= 7) { 214 shutDownMillis = in.readLong(); 215 } else { 216 shutDownMillis = Long.valueOf(in.readInt()); 217 } 218 if (shutDownMillis == 0 && CompatChanges.isChangeEnabled( 219 SoftApConfiguration.REMOVE_ZERO_FOR_TIMEOUT_SETTING)) { 220 shutDownMillis = SoftApConfiguration.DEFAULT_TIMEOUT; 221 } 222 configBuilder.setShutdownTimeoutMillis(shutDownMillis); 223 configBuilder.setClientControlByUserEnabled(in.readBoolean()); 224 int numberOfBlockedClient = in.readInt(); 225 List<MacAddress> blockedList = new ArrayList<>( 226 macAddressListFromByteArray(in, numberOfBlockedClient)); 227 int numberOfAllowedClient = in.readInt(); 228 List<MacAddress> allowedList = new ArrayList<>( 229 macAddressListFromByteArray(in, numberOfAllowedClient)); 230 configBuilder.setBlockedClientList(blockedList); 231 configBuilder.setAllowedClientList(allowedList); 232 } 233 if (version >= 6) { 234 configBuilder.setAutoShutdownEnabled(in.readBoolean()); 235 } else { 236 // Migrate data out of settings. 237 WifiMigration.SettingsMigrationData migrationData = 238 mSettingsMigrationDataHolder.retrieveData(); 239 if (migrationData == null) { 240 Log.e(TAG, "No migration data present"); 241 } else { 242 configBuilder.setAutoShutdownEnabled(migrationData.isSoftApTimeoutEnabled()); 243 } 244 } 245 if (version >= 8 && SdkLevel.isAtLeastS()) { 246 configBuilder.setBridgedModeOpportunisticShutdownEnabled(in.readBoolean()); 247 configBuilder.setMacRandomizationSetting(in.readInt()); 248 int numOfChannels = in.readInt(); 249 SparseIntArray channels = new SparseIntArray(numOfChannels); 250 for (int i = 0; i < numOfChannels; i++) { 251 channels.put(in.readInt(), in.readInt()); 252 } 253 configBuilder.setChannels(channels); 254 configBuilder.setIeee80211axEnabled(in.readBoolean()); 255 } 256 return configBuilder.build(); 257 } catch (IOException | BackupUtils.BadVersionException 258 | IllegalArgumentException | XmlPullParserException e) { 259 Log.e(TAG, "Invalid backup data received, Exception: " + e); 260 } 261 return null; 262 } 263 writeMacAddressList(DataOutputStream out, List<MacAddress> macList)264 private void writeMacAddressList(DataOutputStream out, List<MacAddress> macList) 265 throws IOException { 266 out.writeInt(macList.size()); 267 Iterator<MacAddress> iterator = macList.iterator(); 268 while (iterator.hasNext()) { 269 byte[] mac = iterator.next().toByteArray(); 270 out.write(mac, 0, ETHER_ADDR_LEN); 271 } 272 } 273 macAddressListFromByteArray(DataInputStream in, int numberOfClients)274 private List<MacAddress> macAddressListFromByteArray(DataInputStream in, int numberOfClients) 275 throws IOException { 276 List<MacAddress> macList = new ArrayList<>(); 277 for (int i = 0; i < numberOfClients; i++) { 278 byte[] mac = new byte[ETHER_ADDR_LEN]; 279 in.read(mac, 0, ETHER_ADDR_LEN); 280 macList.add(MacAddress.fromBytes(mac)); 281 } 282 return macList; 283 } 284 } 285