Exception - Failed to lookup symbol 'DTLS_client_method': dlsym(RTLD_DEFAULT, DTLS_client_method): symbol not found

[alexrocks59]

Exception generate when attempting to connect:

    final bindAdress = InternetAddress.anyIPv4;
    final peerAddress = InternetAddress(meterIpAddress);
    const peerPort = 8081;
    const _ciphers = 'ECDHE-ECDSA-AES128-CCM8';
    const _identity = "MEC";

    const _preSharedKey = "secretPSK";

    ByteData data = await rootBundle.load('assets/certs/certificate.pem');
    List<Uint8List> cert = [data.buffer.asUint8List()];
  
    final context = DtlsClientContext(
      withTrustedRoots: true,
      rootCertificates: cert,
      ciphers: _ciphers,
      pskCredentialsCallback: (identityHint) {
        XeDebugPrint.success(msg: 'identityHint: $identityHint');
        return PskCredentials(
          identity: Uint8List.fromList(utf8.encode(_identity)),
          preSharedKey: Uint8List.fromList(utf8.encode(_preSharedKey)),
        );
      },
    );

    final dtlsClient = await DtlsClient.bind(bindAdress, 0);
    final DtlsConnection connection;

    try {
      connection = await dtlsClient.connect(peerAddress, peerPort, context);
    } on Exception {
      await dtlsClient.close();
      rethrow;
    }

[JKRhb]

Thank you for opening this issue! Can you provide more information on which OpenSSL version you are using and try to generate a self-contained example to reproduce the exception? Also, could you post the full stack trace?

[babincc]

I have run into the same issue. I have a Flutter plugin that I am trying to convert to a pure Dart package. When I run this code in the Flutter plugin, it works fine; however, it fails in the pure Dart package.

...

final DtlsClientContext clientContext = DtlsClientContext(
      verify: true,
      withTrustedRoots: true,
      ciphers: 'PSK-AES128-GCM-SHA256',
      pskCredentialsCallback: (_) {
        return PskCredentials(
          identity: utf8.encode(appId),
          preSharedKey: clientKeyBytes,
        );
      },
    );

...

dtlsData.dtlsClient = await DtlsClient.bind(ipAddress, 0);

dtlsData.connection = await dtlsData.dtlsClient!.connect(
  InternetAddress(bridgeIpAddr),
  2100,
  clientContext,
  timeout: const Duration(seconds: 5),
);

In the Flutter plugin, there is a .podspec with the line s.dependency 'OpenSSL-Universal' in my ios and macos folders. I don't know if I added that myself or if it was auto-generated. Since pure Dart doesn't use cocoa pods, this isn't an option for the Dart package. I assume this is where the issue is. Also, in both cases, I am running my plugin/package in a Flutter app on an iPhone simulator.

@alexrocks59 Did you ever get this issue solved?

[JKRhb]

Thank you for your comment, @babincc, and the additional context! Do you know which versions of OpenSSL you have installed locally and via OpenSSL-Universal in your Flutter plugin?

[babincc]

Running openssl version in the terminal gives me OpenSSL 3.4.0 22 Oct 2024 (Library: OpenSSL 3.4.0 22 Oct 2024)

And this was in my Podfile.lock in my Flutter plugin version of the app: - OpenSSL-Universal (3.1.5004)