Troubles when introduce new extension on ClientHello

[jaimesaez97]

Hello.

I am trying to introduce a new APPLICATION_ID extension into ClientHello message.
I have added the extension QkdApplicationIdExtension into tlsextensions.py script, but I am getting an error when receiving ClientHello on server side.

• In _handshakeClientAsyncHelper function, I call self._clientSendClientHello with an extra parameter: the QKD_ID that I want to introduce. Also, in settings I have introduced a new field called qkd_psk to carry the application ID.
• In _clientSendClientHello function, the ClientHello message creation is performed in a correct way, but when the message is sent through _sendMsg something does not work correctly.
  • I think it is on buf = msg.write() statement.
• In _handshakeServerAsyncHelper function, whene ClientHello is retrieved from _serverGetClientHello function, the message does not contains the QkdApplicationIdExtension.

I think the problem is in the message generation through a bytearray.

Could you help me?

Thank you very much.

[tomato42]

does not work correctly.

• I think it is on buf = msg.write() statement.

that would suggest serialisation being incomplete; every extension needs to inherit from TLSExtension and implement at least the extData property and parse method (either directly or through inheritance, as you can see in the example below

Could you help me?

without code it's hard to do, I'm also not familiar with this extension

there are multiple things that need to be updated to fully support an extension

the closest thing to help I can offer is suggest to look at PR #338, more specifically commits e7de0ff, 82b2cf2, 82bba8b, and b3f8928 there