Issue with retransmission during handshake

[nx7400]

Hi,
I observe incorrect retransmission behaviors during handshake.

1. The first case is sending a retransmission when it is not needed because the server response comes in less than 1 second.
   
   Additionally, the retransmission is sent at a completely unanticipated moment of the handshake.

2. The second case is not sending the retransmission at the right moment when the server needs more than 1 second to respond.
   
   Here too, the retransmission is sent at unanticipated moment.

3. The third case also contains a issue with retransmission but additionally Client dose not respond to the Server Hello Done message.
   

In my application I use your DTLS code only for DTLS Clients. Server part is an independent application that uses plain OpenSSL in version 1.1.1d.
In the cases described above I use 5 such Clients that try to connect to the server.

I did quite detailed review of your code in search of the issue but failed to find the cause.
Do you have any idea what the issue might be or what I am doing wrong?

[sdamm]

Sorry for the late response.

This is a bug in asio_dtls which I don't know how to fix.
On the fix_handshake_timeouts branch I have a Fix which has the following downsides:

• timeout in handshake returns "Connection timed out" which is only somewhat correct
• the timeout closes the Socket (cancel would be an alternative, with some new downsides)

Could you please confirm that this fixes the issue (aside from the above mentioned Problems)?