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.compat.Compatibility; 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); 107 108 XmlUtil.writeDocumentEnd(xmlOut, XML_TAG_DOCUMENT_HEADER); 109 110 } else { 111 if (SdkLevel.isAtLeastS()) { 112 out.writeInt(LAST_SAP_BACKUP_DATA_VERSION_IN_S); 113 } else { 114 out.writeInt(LAST_SAP_BACKUP_DATA_VERSION_IN_R); 115 } 116 BackupUtils.writeString(out, config.getSsid()); 117 out.writeInt(config.getBand()); 118 out.writeInt(config.getChannel()); 119 BackupUtils.writeString(out, config.getPassphrase()); 120 out.writeInt(config.getSecurityType()); 121 out.writeBoolean(config.isHiddenSsid()); 122 out.writeInt(config.getMaxNumberOfClients()); 123 out.writeLong(config.getShutdownTimeoutMillis()); 124 out.writeBoolean(config.isClientControlByUserEnabled()); 125 writeMacAddressList(out, config.getBlockedClientList()); 126 writeMacAddressList(out, config.getAllowedClientList()); 127 out.writeBoolean(config.isAutoShutdownEnabled()); 128 if (SdkLevel.isAtLeastS()) { 129 out.writeBoolean(config.isBridgedModeOpportunisticShutdownEnabled()); 130 out.writeInt(config.getMacRandomizationSetting()); 131 SparseIntArray channels = config.getChannels(); 132 int numOfChannels = channels.size(); 133 out.writeInt(numOfChannels); 134 for (int i = 0; i < numOfChannels; i++) { 135 out.writeInt(channels.keyAt(i)); 136 out.writeInt(channels.valueAt(i)); 137 } 138 out.writeBoolean(config.isIeee80211axEnabled()); 139 } 140 } 141 return baos.toByteArray(); 142 } catch (IOException | XmlPullParserException e) { 143 Log.e(TAG, "Error retrieving the backup data from SoftApConfiguration: " + config 144 + ", exception " + e); 145 } 146 return new byte[0]; 147 } 148 149 /** 150 * Parse out the configurations from the back up data. 151 * 152 * @param data raw byte stream representing the data. 153 * @return Soft ap config retrieved from the backed up data. 154 */ retrieveSoftApConfigurationFromBackupData(byte[] data)155 public SoftApConfiguration retrieveSoftApConfigurationFromBackupData(byte[] data) { 156 if (data == null || data.length == 0) { 157 Log.e(TAG, "Invalid backup data received"); 158 return null; 159 } 160 SoftApConfiguration.Builder configBuilder = new SoftApConfiguration.Builder(); 161 try { 162 DataInputStream in = new DataInputStream(new ByteArrayInputStream(data)); 163 int version = in.readInt(); 164 // Starting from T, frameworks support to downgrade restore configuration. 165 if ((!SdkLevel.isAtLeastT() && version > LAST_SAP_BACKUP_DATA_VERSION_IN_S) 166 || version < 1) { 167 throw new BackupUtils.BadVersionException("Unknown Backup Serialization Version"); 168 } 169 170 if (version == 1) return null; // Version 1 is a bad dataset. 171 Log.i(TAG, "The backed-up version is " + version); 172 173 if (version >= SUPPORTED_SAP_BACKUP_XML_DATA_VERSION) { 174 final XmlPullParser xmlIn = Xml.newPullParser(); 175 ByteArrayInputStream inputStream = new ByteArrayInputStream(data); 176 // The first 4 bytes are designed to store version 177 inputStream.skip(Integer.BYTES); 178 xmlIn.setInput(inputStream, StandardCharsets.UTF_8.name()); 179 XmlUtil.gotoDocumentStart(xmlIn, XML_TAG_DOCUMENT_HEADER); 180 int rootTagDepth = xmlIn.getDepth(); 181 return XmlUtil.SoftApConfigurationXmlUtil 182 .parseFromXml(xmlIn, rootTagDepth, mSettingsMigrationDataHolder); 183 } 184 configBuilder.setSsid(BackupUtils.readString(in)); 185 186 int band; 187 if (version < 4) { 188 band = ApConfigUtil.convertWifiConfigBandToSoftApConfigBand(in.readInt()); 189 } else { 190 band = in.readInt(); 191 } 192 int channel = in.readInt(); 193 if (channel == 0) { 194 configBuilder.setBand(band); 195 } else { 196 configBuilder.setChannel(channel, band); 197 } 198 String passphrase = BackupUtils.readString(in); 199 int securityType = in.readInt(); 200 if (version < 4 && securityType == WifiConfiguration.KeyMgmt.WPA2_PSK) { 201 configBuilder.setPassphrase(passphrase, SoftApConfiguration.SECURITY_TYPE_WPA2_PSK); 202 } else if (version >= 4 && securityType != SoftApConfiguration.SECURITY_TYPE_OPEN) { 203 configBuilder.setPassphrase(passphrase, securityType); 204 } 205 if (version >= 3) { 206 configBuilder.setHiddenSsid(in.readBoolean()); 207 } 208 if (version >= 5) { 209 configBuilder.setMaxNumberOfClients(in.readInt()); 210 long shutDownMillis; 211 if (version >= 7) { 212 shutDownMillis = in.readLong(); 213 } else { 214 shutDownMillis = Long.valueOf(in.readInt()); 215 } 216 if (shutDownMillis == 0 && Compatibility.isChangeEnabled( 217 SoftApConfiguration.REMOVE_ZERO_FOR_TIMEOUT_SETTING)) { 218 shutDownMillis = SoftApConfiguration.DEFAULT_TIMEOUT; 219 } 220 configBuilder.setShutdownTimeoutMillis(shutDownMillis); 221 configBuilder.setClientControlByUserEnabled(in.readBoolean()); 222 int numberOfBlockedClient = in.readInt(); 223 List<MacAddress> blockedList = new ArrayList<>( 224 macAddressListFromByteArray(in, numberOfBlockedClient)); 225 int numberOfAllowedClient = in.readInt(); 226 List<MacAddress> allowedList = new ArrayList<>( 227 macAddressListFromByteArray(in, numberOfAllowedClient)); 228 configBuilder.setBlockedClientList(blockedList); 229 configBuilder.setAllowedClientList(allowedList); 230 } 231 if (version >= 6) { 232 configBuilder.setAutoShutdownEnabled(in.readBoolean()); 233 } else { 234 // Migrate data out of settings. 235 WifiMigration.SettingsMigrationData migrationData = 236 mSettingsMigrationDataHolder.retrieveData(); 237 if (migrationData == null) { 238 Log.e(TAG, "No migration data present"); 239 } else { 240 configBuilder.setAutoShutdownEnabled(migrationData.isSoftApTimeoutEnabled()); 241 } 242 } 243 if (version >= 8 && SdkLevel.isAtLeastS()) { 244 configBuilder.setBridgedModeOpportunisticShutdownEnabled(in.readBoolean()); 245 configBuilder.setMacRandomizationSetting(in.readInt()); 246 int numOfChannels = in.readInt(); 247 SparseIntArray channels = new SparseIntArray(numOfChannels); 248 for (int i = 0; i < numOfChannels; i++) { 249 channels.put(in.readInt(), in.readInt()); 250 } 251 configBuilder.setChannels(channels); 252 configBuilder.setIeee80211axEnabled(in.readBoolean()); 253 } 254 return configBuilder.build(); 255 } catch (IOException | BackupUtils.BadVersionException 256 | IllegalArgumentException | XmlPullParserException e) { 257 Log.e(TAG, "Invalid backup data received, Exception: " + e); 258 } 259 return null; 260 } 261 writeMacAddressList(DataOutputStream out, List<MacAddress> macList)262 private void writeMacAddressList(DataOutputStream out, List<MacAddress> macList) 263 throws IOException { 264 out.writeInt(macList.size()); 265 Iterator<MacAddress> iterator = macList.iterator(); 266 while (iterator.hasNext()) { 267 byte[] mac = iterator.next().toByteArray(); 268 out.write(mac, 0, ETHER_ADDR_LEN); 269 } 270 } 271 macAddressListFromByteArray(DataInputStream in, int numberOfClients)272 private List<MacAddress> macAddressListFromByteArray(DataInputStream in, int numberOfClients) 273 throws IOException { 274 List<MacAddress> macList = new ArrayList<>(); 275 for (int i = 0; i < numberOfClients; i++) { 276 byte[] mac = new byte[ETHER_ADDR_LEN]; 277 in.read(mac, 0, ETHER_ADDR_LEN); 278 macList.add(MacAddress.fromBytes(mac)); 279 } 280 return macList; 281 } 282 } 283