content: /*
   * Copyright (C) 2016 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.aware;
  
  import android.content.Context;
  import android.content.pm.PackageManager;
  import android.hardware.wifi.V1_0.Constants;
  
  /**
   * Provides utilities for the Wifi Aware manager/service.
   *
   * @hide
   */
  public class WifiAwareUtils {
      /**
       * Per spec: The Service Name is a UTF-8 encoded string from 1 to 255 bytes in length. The
       * only acceptable single-byte UTF-8 symbols for a Service Name are alphanumeric values (A-Z,
       * a-z, 0-9), the hyphen ('-'), and the period ('.'). All valid multi-byte UTF-8 characters
       * are acceptable in a Service Name.
       */
      public static void validateServiceName(byte[] serviceNameData) throws IllegalArgumentException {
          if (serviceNameData == null) {
              throw new IllegalArgumentException("Invalid service name - null");
          }
  
          if (serviceNameData.length < 1 || serviceNameData.length > 255) {
              throw new IllegalArgumentException("Invalid service name length - must be between "
                      + "1 and 255 bytes (UTF-8 encoding)");
          }
  
          int index = 0;
          while (index < serviceNameData.length) {
              byte b = serviceNameData[index];
              if ((b & 0x80) == 0x00) {
                  if (!((b >= '0' && b <= '9') || (b >= 'a' && b <= 'z') || (b >= 'A' && b <= 'Z')
                          || b == '-' || b == '.')) {
                      throw new IllegalArgumentException("Invalid service name - illegal characters,"
                              + " allowed = (0-9, a-z,A-Z, -, .)");
                  }
              }
              ++index;
          }
      }
  
      /**
       * Validates that the passphrase is a non-null string of the right size (per the HAL min/max
       * length parameters).
       *
       * @param passphrase Passphrase to test
       * @return true if passphrase is valid, false if not
       */
      public static boolean validatePassphrase(String passphrase) {
          if (passphrase == null
                  || passphrase.length() < Constants.NanParamSizeLimits.MIN_PASSPHRASE_LENGTH
                  || passphrase.length() > Constants.NanParamSizeLimits.MAX_PASSPHRASE_LENGTH) {
              return false;
          }
  
          return true;
      }
  
      /**
       * Validates that the PMK is a non-null byte array of the right size (32 bytes per spec).
       *
       * @param pmk PMK to test
       * @return true if PMK is valid, false if not
       */
      public static boolean validatePmk(byte[] pmk) {
          if (pmk == null || pmk.length != 32) {
              return false;
          }
  
          return true;
      }
  
      /**
       * Returns true if the App version is older than minVersion.
       */
      public static boolean isLegacyVersion(Context context, int minVersion) {
          try {
              if (context.getPackageManager().getApplicationInfo(context.getOpPackageName(), 0)
                      .targetSdkVersion < minVersion) {
                  return true;
              }
          } catch (PackageManager.NameNotFoundException e) {
              // In case of exception, assume known app (more strict checking)
              // Note: This case will never happen since checkPackage is
              // called to verify valididity before checking App's version.
          }
          return false;
      }
  }
  