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   1 /**
   2  * Copyright (c) 2010-2023 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.anel.internal.auth;
  14
  15 import java.util.Base64;
  16 import java.util.regex.Matcher;
  17 import java.util.regex.Pattern;
  18
  19 import org.eclipse.jdt.annotation.NonNullByDefault;
  20 import org.eclipse.jdt.annotation.Nullable;
  21
  22 /**
  23  * This class determines the authentication method from a status response of an ANEL device.
  24  *
  25  * @author Patrick Koenemann - Initial contribution
  26  */
  27 @NonNullByDefault
  28 public class AnelAuthentication {
  29
  30     public enum AuthMethod {
  31         PLAIN,
  32         BASE64,
  33         XORBASE64;
  34
  35         private static final Pattern NAME_AND_FIRMWARE_PATTERN = Pattern.compile(":NET-PWRCTRL_0?(\\d+\\.\\d)");
  36         private static final Pattern LAST_SEGMENT_FIRMWARE_PATTERN = Pattern.compile(":(\\d+\\.\\d)$");
  37
  38         private static final String MIN_FIRMWARE_BASE64 = "6.0";
  39         private static final String MIN_FIRMWARE_XOR_BASE64 = "6.1";
  40
  41         public static AuthMethod of(String status) {
  42             if (status.isEmpty()) {
  43                 return PLAIN; // fallback
  44             }
  45             if (status.trim().endsWith(":xor") || status.contains(":xor:")) {
  46                 return XORBASE64;
  47             }
  48             final String firmwareVersion = getFirmwareVersion(status);
  49             if (firmwareVersion == null) {
  50                 return PLAIN;
  51             }
  52             if (firmwareVersion.compareTo(MIN_FIRMWARE_XOR_BASE64) >= 0) {
  53                 return XORBASE64; // >= 6.1
  54             }
  55             if (firmwareVersion.compareTo(MIN_FIRMWARE_BASE64) >= 0) {
  56                 return BASE64; // exactly 6.0
  57             }
  58             return PLAIN; // fallback
  59         }
  60
  61         private static @Nullable String getFirmwareVersion(String fullStatusStringOrFirmwareVersion) {
  62             final Matcher matcher1 = NAME_AND_FIRMWARE_PATTERN.matcher(fullStatusStringOrFirmwareVersion);
  63             if (matcher1.find()) {
  64                 return matcher1.group(1);
  65             }
  66             final Matcher matcher2 = LAST_SEGMENT_FIRMWARE_PATTERN.matcher(fullStatusStringOrFirmwareVersion.trim());
  67             if (matcher2.find()) {
  68                 return matcher2.group(1);
  69             }
  70             return null;
  71         }
  72     }
  73
  74     public static String getUserPasswordString(@Nullable String user, @Nullable String password,
  75             @Nullable AuthMethod authMethod) {
  76         final String userPassword = (user == null ? "" : user) + (password == null ? "" : password);
  77         if (authMethod == null || authMethod == AuthMethod.PLAIN) {
  78             return userPassword;
  79         }
  80
  81         if (authMethod == AuthMethod.BASE64 || password == null || password.isEmpty()) {
  82             return Base64.getEncoder().encodeToString(userPassword.getBytes());
  83         }
  84
  85         if (authMethod == AuthMethod.XORBASE64) {
  86             final StringBuilder result = new StringBuilder();
  87
  88             // XOR
  89             for (int c = 0; c < userPassword.length(); c++) {
  90                 result.append((char) (userPassword.charAt(c) ^ password.charAt(c % password.length())));
  91             }
  92
  93             return Base64.getEncoder().encodeToString(result.toString().getBytes());
  94         }
  95
  96         throw new UnsupportedOperationException("Unknown auth method: " + authMethod);
  97     }
  98 }