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   1 /**
   2  * Copyright (c) 2010-2020 Contributors to the openHAB project
   3  *
   4  * See the NOTICE file(s) distributed with this work for additional
   5  * information.
   6  *
   7  * This program and the accompanying materials are made available under the
   8  * terms of the Eclipse Public License 2.0 which is available at
   9  * http://www.eclipse.org/legal/epl-2.0
  10  *
  11  * SPDX-License-Identifier: EPL-2.0
  12  */
  13 package org.openhab.binding.internal.kostal.inverter.thirdgeneration;
  14
  15 import static org.openhab.binding.internal.kostal.inverter.thirdgeneration.ThirdGenerationBindingConstants.*;
  16
  17 import java.io.UnsupportedEncodingException;
  18 import java.security.InvalidAlgorithmParameterException;
  19 import java.security.InvalidKeyException;
  20 import java.security.NoSuchAlgorithmException;
  21 import java.security.SecureRandom;
  22 import java.security.spec.InvalidKeySpecException;
  23 import java.util.Base64;
  24 import java.util.List;
  25 import java.util.Map;
  26 import java.util.Map.Entry;
  27 import java.util.concurrent.ExecutionException;
  28 import java.util.concurrent.ScheduledFuture;
  29 import java.util.concurrent.TimeUnit;
  30 import java.util.concurrent.TimeoutException;
  31
  32 import javax.crypto.BadPaddingException;
  33 import javax.crypto.Cipher;
  34 import javax.crypto.IllegalBlockSizeException;
  35 import javax.crypto.Mac;
  36 import javax.crypto.NoSuchPaddingException;
  37 import javax.crypto.spec.GCMParameterSpec;
  38 import javax.crypto.spec.SecretKeySpec;
  39
  40 import org.eclipse.jdt.annotation.NonNullByDefault;
  41 import org.eclipse.jdt.annotation.Nullable;
  42 import org.eclipse.jetty.client.HttpClient;
  43 import org.eclipse.jetty.client.api.ContentResponse;
  44 import org.openhab.core.library.types.DecimalType;
  45 import org.openhab.core.library.types.QuantityType;
  46 import org.openhab.core.library.unit.SIUnits;
  47 import org.openhab.core.library.unit.SmartHomeUnits;
  48 import org.openhab.core.thing.ChannelUID;
  49 import org.openhab.core.thing.Thing;
  50 import org.openhab.core.thing.ThingStatus;
  51 import org.openhab.core.thing.ThingStatusDetail;
  52 import org.openhab.core.thing.binding.BaseThingHandler;
  53 import org.openhab.core.types.Command;
  54 import org.slf4j.Logger;
  55 import org.slf4j.LoggerFactory;
  56
  57 import com.google.gson.JsonArray;
  58 import com.google.gson.JsonObject;
  59
  60 /**
  61  * The {@link ThirdGenerationHandler} is responsible for handling commands, which are
  62  * sent to one of the channels.
  63  *
  64  * @author René Stakemeier - Initial contribution
  65  */
  66 @NonNullByDefault
  67 public class ThirdGenerationHandler extends BaseThingHandler {
  68
  69     /*
  70      * operations used for authentication
  71      */
  72     private static final String AUTH_START = "/auth/start";
  73     private static final String AUTH_FINISH = "/auth/finish";
  74     private static final String AUTH_CREATE_SESSION = "/auth/create_session";
  75
  76     /*
  77      * operations used for gathering process data from the device
  78      */
  79     private static final String PROCESSDATA = "/processdata";
  80
  81     /*
  82      * After the authentication the result (the session id) is stored here and used to "sign" future requests
  83      */
  84     private @Nullable String sessionId;
  85     /*
  86      * The configuration file containing the host, the password and the refresh interval
  87      */
  88     private @NonNullByDefault({}) ThirdGenerationConfiguration config;
  89
  90     private @Nullable ScheduledFuture<?> refreshScheduler;
  91
  92     private @Nullable HttpClient httpClient;
  93
  94     private ThirdGenerationInverterTypes inverterType;
  95
  96     private final Logger logger = LoggerFactory.getLogger(this.getClass());
  97
  98     /**
  99      * Constructor of this class
 100      *
 101      * @param thing the thing
 102      * @param httpClient the httpClient used for communication
 103      * @param inverterType the type of the device
 104      */
 105     public ThirdGenerationHandler(Thing thing, HttpClient httpClient, ThirdGenerationInverterTypes inverterType) {
 106         super(thing);
 107         this.inverterType = inverterType;
 108         this.httpClient = httpClient;
 109     }
 110
 111     @Override
 112     public void handleCommand(ChannelUID channelUID, Command command) {
 113         // All channels are readonly and updated by the scheduler
 114     }
 115
 116     @Override
 117     public void dispose() {
 118         if (refreshScheduler != null) {
 119             refreshScheduler.cancel(true);
 120             refreshScheduler = null;
 121         }
 122         super.dispose();
 123     }
 124
 125     @Override
 126     public void initialize() {
 127         config = getConfigAs(ThirdGenerationConfiguration.class);
 128         // temporary value while initializing
 129         updateStatus(ThingStatus.UNKNOWN);
 130
 131         // Start the authentication
 132         scheduler.schedule(this::authenticate, 1, TimeUnit.SECONDS);
 133
 134         // Start the update scheduler as configured
 135         refreshScheduler = scheduler.scheduleWithFixedDelay(this::updateChannelValues, 10,
 136                 config.refreshInternalInSeconds, TimeUnit.SECONDS);
 137     }
 138
 139     /**
 140      * The API supports the resolution of multiple values at a time
 141      *
 142      * Therefore this methods builds one request to gather all information for the current inverter.
 143      * The list contains all channels as defined in {@link ThirdGenerationMappingInverterToChannel} for the
 144      * current inverter
 145      *
 146      */
 147     private void updateChannelValues() {
 148         Map<String, List<ThirdGenerationChannelMappingToWebApi>> channelList = ThirdGenerationMappingInverterToChannel
 149                 .getModuleToChannelsMappingForInverter(inverterType);
 150         JsonArray updateMessageJsonArray = getUpdateChannelMessage(channelList);
 151
 152         // Send the API request to get values for all channels
 153         ContentResponse updateMessageContentResponse;
 154         try {
 155             updateMessageContentResponse = ThirdGenerationHttpHelper.executeHttpPost(httpClient, config.url,
 156                     PROCESSDATA, updateMessageJsonArray, sessionId);
 157             if (updateMessageContentResponse.getStatus() == 404) {
 158                 // Module not found
 159                 updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.OFFLINE.COMMUNICATION_ERROR,
 160                         COMMUNICATION_ERROR_INCOMPATIBLE_DEVICE);
 161                 return;
 162             }
 163             if (updateMessageContentResponse.getStatus() == 503) {
 164                 // Communication error (e.g. during initial boot of the SCB)
 165                 updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.OFFLINE.COMMUNICATION_ERROR,
 166                         COMMUNICATION_ERROR_HTTP);
 167                 return;
 168             }
 169             if (updateMessageContentResponse.getStatus() == 401) {
 170                 // session not valid (timed out? device rebooted?)
 171                 logger.info("Session expired - performing retry");
 172                 authenticate();
 173                 // Retry
 174                 updateMessageContentResponse = ThirdGenerationHttpHelper.executeHttpPost(httpClient, config.url,
 175                         PROCESSDATA, updateMessageJsonArray, sessionId);
 176             }
 177         } catch (TimeoutException | ExecutionException e) {
 178             // Communication problem
 179             updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.OFFLINE.COMMUNICATION_ERROR, COMMUNICATION_ERROR_HTTP);
 180             return;
 181         } catch (InterruptedException e) {
 182             Thread.currentThread().interrupt();
 183             updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.OFFLINE.COMMUNICATION_ERROR, COMMUNICATION_ERROR_HTTP);
 184             return;
 185         }
 186         JsonArray updateMessageResultsJsonArray = ThirdGenerationHttpHelper
 187                 .getJsonArrayFromResponse(updateMessageContentResponse);
 188
 189         // Map the returned values back to the channels and update them
 190         for (int i = 0; i < updateMessageResultsJsonArray.size(); i++) {
 191             JsonObject moduleAnswer = updateMessageResultsJsonArray.get(i).getAsJsonObject();
 192             String moduleName = moduleAnswer.get("moduleid").getAsString();
 193             JsonArray processdata = moduleAnswer.get("processdata").getAsJsonArray();
 194             for (int j = 0; j < processdata.size(); j++) {
 195                 // Update the channels with their new value
 196                 JsonObject newValueObject = processdata.get(j).getAsJsonObject();
 197                 String valueId = newValueObject.get("id").getAsString();
 198                 double valueAsDouble = newValueObject.get("value").getAsDouble();
 199                 ThirdGenerationChannelMappingToWebApi channel = channelList.get(moduleName).stream()
 200                         .filter(c -> c.moduleId.equals(moduleName) && c.processdataId.equals(valueId)).findFirst()
 201                         .get();
 202                 updateChannelValue(channel.channelUID, channel.dataType, valueAsDouble);
 203             }
 204         }
 205         updateStatus(ThingStatus.ONLINE);
 206     }
 207
 208     /**
 209      * Update the channel to the given value.
 210      * The value is set to the matching data (SITypes etc)
 211      *
 212      * @param channeluid Channel to update
 213      * @param dataType target data type
 214      * @param value value
 215      */
 216     private void updateChannelValue(String channeluid, ThirdGenerationChannelDatatypes dataType, Double value) {
 217         switch (dataType) {
 218             case INTEGER: {
 219                 updateState(channeluid, new DecimalType(value.longValue()));
 220                 break;
 221             }
 222             case PERCEMTAGE: {
 223                 updateState(channeluid, new QuantityType<>(value, SmartHomeUnits.PERCENT));
 224                 break;
 225             }
 226             case KILOGRAM: {
 227                 updateState(channeluid, new QuantityType<>(value / 1000, SIUnits.KILOGRAM));
 228                 break;
 229             }
 230             case SECONDS: {
 231                 updateState(channeluid, new QuantityType<>(value, SmartHomeUnits.SECOND));
 232                 break;
 233             }
 234             case KILOWATT_HOUR: {
 235                 updateState(channeluid, new QuantityType<>(value / 1000, SmartHomeUnits.KILOWATT_HOUR));
 236                 break;
 237             }
 238             case WATT: {
 239                 updateState(channeluid, new QuantityType<>(value, SmartHomeUnits.WATT));
 240                 break;
 241             }
 242             case AMPERE: {
 243                 updateState(channeluid, new QuantityType<>(value, SmartHomeUnits.AMPERE));
 244                 break;
 245             }
 246             case AMPERE_HOUR: {
 247                 // Ampere hours are not supported by ESH, but 1 AH is equal tp 3600 coulomb...
 248                 updateState(channeluid, new QuantityType<>(value * 3600, SmartHomeUnits.COULOMB));
 249                 break;
 250             }
 251             case VOLT: {
 252                 updateState(channeluid, new QuantityType<>(value, SmartHomeUnits.VOLT));
 253                 break;
 254             }
 255             default: {
 256                 // unknown datatype
 257                 logger.debug("{} not known!", dataType);
 258             }
 259         }
 260     }
 261
 262     /**
 263      * Creates the message which has to be send to the inverter to gather the current informations for all channels
 264      *
 265      * @param channelList channels of this thing
 266      * @return the JSON array to send to the device
 267      */
 268     private JsonArray getUpdateChannelMessage(Map<String, List<ThirdGenerationChannelMappingToWebApi>> channelList) {
 269         // Build the message to send to the inverter
 270         JsonArray updateMessageJsonArray = new JsonArray();
 271         for (Entry<String, List<ThirdGenerationChannelMappingToWebApi>> moduleId : channelList.entrySet()) {
 272             JsonObject moduleJsonObject = new JsonObject();
 273             moduleJsonObject.addProperty("moduleid", moduleId.getKey());
 274
 275             JsonArray processdataNames = new JsonArray();
 276             for (ThirdGenerationChannelMappingToWebApi processdata : channelList.get(moduleId.getKey())) {
 277                 processdataNames.add(processdata.processdataId);
 278             }
 279             moduleJsonObject.add("processdataids", processdataNames);
 280             updateMessageJsonArray.add(moduleJsonObject);
 281         }
 282         return updateMessageJsonArray;
 283     }
 284
 285     /**
 286      * This function is used to authenticate against the SCB.
 287      * SCB uses PBKDF2 and AES256 GCM mode with a slightly modified authentication message.
 288      * The authentication will fail on JRE < 8u162. since the security policy is set to "limited" by default (see readme
 289      * for fix)
 290      */
 291     private final void authenticate() {
 292         // Create random numbers
 293         String clientNonce = ThirdGenerationEncryptionHelper.createClientNonce();
 294         // Perform first step of authentication
 295         JsonObject authMeJsonObject = new JsonObject();
 296         authMeJsonObject.addProperty("username", USER_TYPE);
 297         authMeJsonObject.addProperty("nonce", clientNonce);
 298
 299         ContentResponse authStartResponseContentResponse;
 300         try {
 301             authStartResponseContentResponse = ThirdGenerationHttpHelper.executeHttpPost(httpClient, config.url,
 302                     AUTH_START, authMeJsonObject);
 303
 304             // 200 is the desired status code
 305             int statusCode = authStartResponseContentResponse.getStatus();
 306
 307             if (statusCode == 400) {
 308                 // Invalid user (which is hard coded and therefore can not be wrong until the api is changed by the
 309                 // manufacturer
 310                 updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.OFFLINE.COMMUNICATION_ERROR,
 311                         COMMUNICATION_ERROR_API_CHANGED);
 312                 return;
 313             }
 314             if (statusCode == 403) {
 315                 // User is logged
 316                 // This can happen, if the user had to many bad attempts of entering the password in the web
 317                 // front end
 318                 updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.OFFLINE.CONFIGURATION_ERROR,
 319                         COMMUNICATION_ERROR_USER_ACCOUNT_LOCKED);
 320                 return;
 321             }
 322
 323             if (statusCode == 503) {
 324                 // internal communication error
 325                 // This can happen if the device is not ready yet for communication
 326                 updateStatus(ThingStatus.UNINITIALIZED);
 327                 return;
 328             }
 329         } catch (InterruptedException | TimeoutException | ExecutionException e) {
 330             updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.OFFLINE.COMMUNICATION_ERROR, COMMUNICATION_ERROR_HTTP);
 331             return;
 332         }
 333         JsonObject authMeResponseJsonObject = ThirdGenerationHttpHelper
 334                 .getJsonObjectFromResponse(authStartResponseContentResponse);
 335
 336         // Extract information from the response
 337         String salt = authMeResponseJsonObject.get("salt").getAsString();
 338         String serverNonce = authMeResponseJsonObject.get("nonce").getAsString();
 339         int rounds = authMeResponseJsonObject.get("rounds").getAsInt();
 340         String transactionId = authMeResponseJsonObject.get("transactionId").getAsString();
 341
 342         // Do the cryptography stuff (magic happens here)
 343         byte[] saltedPasswort;
 344         byte[] clientKey;
 345         byte[] serverKey;
 346         byte[] storedKey;
 347         byte[] clientSignature;
 348         byte[] serverSignature;
 349         String authMessage;
 350         try {
 351             saltedPasswort = ThirdGenerationEncryptionHelper.getPBKDF2Hash(config.userPassword,
 352                     Base64.getDecoder().decode(salt), rounds);
 353             clientKey = ThirdGenerationEncryptionHelper.getHMACSha256(saltedPasswort, "Client Key");
 354             serverKey = ThirdGenerationEncryptionHelper.getHMACSha256(saltedPasswort, "Server Key");
 355             storedKey = ThirdGenerationEncryptionHelper.getSha256Hash(clientKey);
 356             authMessage = String.format("n=%s,r=%s,r=%s,s=%s,i=%d,c=biws,r=%s", USER_TYPE, clientNonce, serverNonce,
 357                     salt, rounds, serverNonce);
 358             clientSignature = ThirdGenerationEncryptionHelper.getHMACSha256(storedKey, authMessage);
 359             serverSignature = ThirdGenerationEncryptionHelper.getHMACSha256(serverKey, authMessage);
 360         } catch (NoSuchAlgorithmException | InvalidKeySpecException | InvalidKeyException | IllegalStateException e2) {
 361             updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.OFFLINE.COMMUNICATION_ERROR,
 362                     COMMUNICATION_ERROR_AUTHENTICATION);
 363             return;
 364         }
 365         String clientProof = ThirdGenerationEncryptionHelper.createClientProof(clientSignature, clientKey);
 366         // Perform step 2 of the authentication
 367         JsonObject authFinishJsonObject = new JsonObject();
 368         authFinishJsonObject.addProperty("transactionId", transactionId);
 369         authFinishJsonObject.addProperty("proof", clientProof);
 370
 371         ContentResponse authFinishResponseContentResponse;
 372         JsonObject authFinishResponseJsonObject;
 373         try {
 374             authFinishResponseContentResponse = ThirdGenerationHttpHelper.executeHttpPost(httpClient, config.url,
 375                     AUTH_FINISH, authFinishJsonObject);
 376             authFinishResponseJsonObject = ThirdGenerationHttpHelper
 377                     .getJsonObjectFromResponse(authFinishResponseContentResponse);
 378             // 200 is the desired status code
 379             if (authFinishResponseContentResponse.getStatus() == 400) {
 380                 // Authentication failed
 381                 updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.OFFLINE.COMMUNICATION_ERROR,
 382                         CONFIGURATION_ERROR_PASSWORD);
 383                 return;
 384             }
 385         } catch (InterruptedException | TimeoutException | ExecutionException e3) {
 386             updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.OFFLINE.COMMUNICATION_ERROR, COMMUNICATION_ERROR_HTTP);
 387             return;
 388         }
 389
 390         // Extract information from the response
 391         byte[] signature = Base64.getDecoder().decode(authFinishResponseJsonObject.get("signature").getAsString());
 392         String token = authFinishResponseJsonObject.get("token").getAsString();
 393
 394         // Validate provided signature against calculated signature
 395         if (!java.util.Arrays.equals(serverSignature, signature)) {
 396             updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.OFFLINE.COMMUNICATION_ERROR,
 397                     COMMUNICATION_ERROR_AUTHENTICATION);
 398             return;
 399         }
 400
 401         // Calculate protocol key
 402         SecretKeySpec signingKey = new SecretKeySpec(storedKey, HMAC_SHA256_ALGORITHM);
 403         Mac mac;
 404         byte[] protocolKeyHMAC;
 405         try {
 406             mac = Mac.getInstance(HMAC_SHA256_ALGORITHM);
 407             mac.init(signingKey);
 408             mac.update("Session Key".getBytes());
 409             mac.update(authMessage.getBytes());
 410             mac.update(clientKey);
 411             protocolKeyHMAC = mac.doFinal();
 412         } catch (NoSuchAlgorithmException | InvalidKeyException e1) {
 413             // Since the necessary libraries are provided, this should not happen
 414             updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.OFFLINE.CONFIGURATION_ERROR,
 415                     COMMUNICATION_ERROR_AUTHENTICATION);
 416             return;
 417         }
 418
 419         byte[] data;
 420         byte[] iv;
 421
 422         // AES GCM stuff
 423         iv = new byte[16];
 424
 425         new SecureRandom().nextBytes(iv);
 426
 427         SecretKeySpec skeySpec = new SecretKeySpec(protocolKeyHMAC, "AES");
 428         GCMParameterSpec param = new GCMParameterSpec(protocolKeyHMAC.length * 8 - AES_GCM_TAG_LENGTH, iv);
 429
 430         Cipher cipher;
 431         try {
 432             cipher = Cipher.getInstance("AES_256/GCM/NOPADDING");
 433             cipher.init(Cipher.ENCRYPT_MODE, skeySpec, param);
 434         } catch (NoSuchAlgorithmException | NoSuchPaddingException | InvalidKeyException
 435                 | InvalidAlgorithmParameterException e1) {
 436             // The java installation does not support AES encryption in GCM mode
 437             updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.OFFLINE.COMMUNICATION_ERROR,
 438                     COMMUNICATION_ERROR_AUTHENTICATION);
 439             return;
 440         }
 441         try {
 442             data = cipher.doFinal(token.getBytes("UTF-8"));
 443         } catch (IllegalBlockSizeException | BadPaddingException | UnsupportedEncodingException e1) {
 444             // No JSON answer received
 445             updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.OFFLINE.COMMUNICATION_ERROR, COMMUNICATION_ERROR_JSON);
 446             return;
 447         }
 448
 449         byte[] ciphertext = new byte[data.length - AES_GCM_TAG_LENGTH / 8];
 450         byte[] gcmTag = new byte[AES_GCM_TAG_LENGTH / 8];
 451         System.arraycopy(data, 0, ciphertext, 0, data.length - AES_GCM_TAG_LENGTH / 8);
 452         System.arraycopy(data, data.length - AES_GCM_TAG_LENGTH / 8, gcmTag, 0, AES_GCM_TAG_LENGTH / 8);
 453
 454         JsonObject createSessionJsonObject = new JsonObject();
 455         createSessionJsonObject.addProperty("transactionId", transactionId);
 456         createSessionJsonObject.addProperty("iv", Base64.getEncoder().encodeToString(iv));
 457         createSessionJsonObject.addProperty("tag", Base64.getEncoder().encodeToString(gcmTag));
 458         createSessionJsonObject.addProperty("payload", Base64.getEncoder().encodeToString(ciphertext));
 459
 460         // finally create the session for further communication
 461         ContentResponse createSessionResponseContentResponse;
 462         JsonObject createSessionResponseJsonObject;
 463         try {
 464             createSessionResponseContentResponse = ThirdGenerationHttpHelper.executeHttpPost(httpClient, config.url,
 465                     AUTH_CREATE_SESSION, createSessionJsonObject);
 466             createSessionResponseJsonObject = ThirdGenerationHttpHelper
 467                     .getJsonObjectFromResponse(createSessionResponseContentResponse);
 468         } catch (InterruptedException | TimeoutException | ExecutionException e) {
 469             updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.OFFLINE.COMMUNICATION_ERROR,
 470                     COMMUNICATION_ERROR_AUTHENTICATION);
 471             return;
 472         }
 473         // 200 is the desired status code
 474         if (createSessionResponseContentResponse.getStatus() == 400) {
 475             // Authentication failed
 476             updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.OFFLINE.COMMUNICATION_ERROR,
 477                     CONFIGURATION_ERROR_PASSWORD);
 478             return;
 479         }
 480
 481         sessionId = createSessionResponseJsonObject.get("sessionId").getAsString();
 482
 483         updateStatus(ThingStatus.ONLINE);
 484     }
 485 }