content: /*
   * Copyright © 2017-2023 WireGuard LLC. All Rights Reserved.
   * SPDX-License-Identifier: Apache-2.0
   */
  
  package org.amnezia.awg.config;
  
  import org.amnezia.awg.util.NonNullForAll;
  
  import java.lang.reflect.Method;
  import java.net.Inet4Address;
  import java.net.Inet6Address;
  import java.net.InetAddress;
  import java.net.UnknownHostException;
  import java.util.regex.Pattern;
  
  import androidx.annotation.Nullable;
  
  /**
   * Utility methods for creating instances of {@link InetAddress}.
   */
  @NonNullForAll
  public final class InetAddresses {
      @Nullable private static final Method PARSER_METHOD;
      private static final Pattern WONT_TOUCH_RESOLVER = Pattern.compile("^(((([0-9A-Fa-f]{1,4}:){7}([0-9A-Fa-f]{1,4}|:))|(([0-9A-Fa-f]{1,4}:){6}(:[0-9A-Fa-f]{1,4}|((25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)(\\.(25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)){3})|:))|(([0-9A-Fa-f]{1,4}:){5}(((:[0-9A-Fa-f]{1,4}){1,2})|:((25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)(\\.(25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)){3})|:))|(([0-9A-Fa-f]{1,4}:){4}(((:[0-9A-Fa-f]{1,4}){1,3})|((:[0-9A-Fa-f]{1,4})?:((25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)(\\.(25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)){3}))|:))|(([0-9A-Fa-f]{1,4}:){3}(((:[0-9A-Fa-f]{1,4}){1,4})|((:[0-9A-Fa-f]{1,4}){0,2}:((25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)(\\.(25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)){3}))|:))|(([0-9A-Fa-f]{1,4}:){2}(((:[0-9A-Fa-f]{1,4}){1,5})|((:[0-9A-Fa-f]{1,4}){0,3}:((25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)(\\.(25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)){3}))|:))|(([0-9A-Fa-f]{1,4}:){1}(((:[0-9A-Fa-f]{1,4}){1,6})|((:[0-9A-Fa-f]{1,4}){0,4}:((25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)(\\.(25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)){3}))|:))|(:(((:[0-9A-Fa-f]{1,4}){1,7})|((:[0-9A-Fa-f]{1,4}){0,5}:((25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)(\\.(25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)){3}))|:)))(%.+)?)|((?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?))$");
      private static final Pattern VALID_HOSTNAME = Pattern.compile("^(?=.{1,255}$)[0-9A-Za-z](?:(?:[0-9A-Za-z]|-){0,61}[0-9A-Za-z])?(?:\\.[0-9A-Za-z](?:(?:[0-9A-Za-z]|-){0,61}[0-9A-Za-z])?)*\\.?$");
  
      static {
          Method m = null;
          try {
              if (android.os.Build.VERSION.SDK_INT < android.os.Build.VERSION_CODES.Q)
                  // noinspection JavaReflectionMemberAccess
                  m = InetAddress.class.getMethod("parseNumericAddress", String.class);
          } catch (final Exception ignored) {
          }
          PARSER_METHOD = m;
      }
  
      private InetAddresses() {
      }
  
      /**
       * Determines whether input is a valid DNS hostname.
       *
       * @param maybeHostname a string that is possibly a DNS hostname
       * @return whether or not maybeHostname is a valid DNS hostname
       */
      public static boolean isHostname(final CharSequence maybeHostname) {
          return VALID_HOSTNAME.matcher(maybeHostname).matches();
      }
  
      /**
       * Parses a numeric IPv4 or IPv6 address without performing any DNS lookups.
       *
       * @param address a string representing the IP address
       * @return an instance of {@link Inet4Address} or {@link Inet6Address}, as appropriate
       */
      public static InetAddress parse(final String address) throws ParseException {
          if (address.isEmpty())
              throw new ParseException(InetAddress.class, address, "Empty address");
          try {
              if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.Q)
                  return android.net.InetAddresses.parseNumericAddress(address);
              else if (PARSER_METHOD != null)
                  return (InetAddress) PARSER_METHOD.invoke(null, address);
              else
                  throw new NoSuchMethodException("parseNumericAddress");
          } catch (final IllegalArgumentException e) {
              throw new ParseException(InetAddress.class, address, e);
          } catch (final Exception e) {
              final Throwable cause = e.getCause();
              // Re-throw parsing exceptions with the original type, as callers might try to catch
              // them. On the other hand, callers cannot be expected to handle reflection failures.
              if (cause instanceof IllegalArgumentException)
                  throw new ParseException(InetAddress.class, address, cause);
              try {
                  if (WONT_TOUCH_RESOLVER.matcher(address).matches())
                      return InetAddress.getByName(address);
                  else
                      throw new ParseException(InetAddress.class, address, "Not an IP address");
              } catch (final UnknownHostException f) {
                  throw new ParseException(InetAddress.class, address, f);
              }
          }
      }
  }
  