Debugging and "plugin" callbacks

[jonkri]

In an e-mail to me, Vincent suggested a system for "plugin" callbacks. This would enable users of hs-
tls to get otherwise hidden debugging information, such as handshake data, through the means of callback functions.

(I personally need the FinishedData value from Network/TLS/Struct.hs.)

[vincenthz]

i'm going to cleanup the hooks, but isn't loggingPacketRecv already enough for receiving FinishedData ? or is there any missing data from it ?

EDIT: actually no, it's the String of the packet. would be fiddly to get data from it.

[vincenthz]

ok, there's now a hook that allow to receive every Handshake message received. is it enough for your use case, or do you need the sent handshake too ?

[jonkri]

Hi Vincent, and thank you for taking a look at this! :-)

The way I understand the situation, we need to be able to access the "Finished" struct sent in the (most recent) handshake of the connection. Since we don't support session resumption, I'm assuming that this will be the first finished message sent by the client. (Does this sound reasonable?)

In case we want to support renegotiation in the future, we will need the first "Finished" struct sent for the most inner-most connection used (which, analogously, I'm assuming to be the first Finished message sent by the server).

In addition to these callbacks, and enough context to decide which data to use, we will need some way of accessing the proper Handshake fields, and exports of their associated types (like FinishedData).

Take care!