Retransmit last flight when in finished

[Sean-Der]

When FSM is in finished and sees a handshake message re-send the last flight again.

[Sean-Der]

@hasheddan @at-wat Looking at the spec I believe FINISHED can be simpler? If we see a handshake when in the FINISHED state do a RTX in case the remote lost the last message.

// [RFC6347 Section-4.2.4]
//                      +-----------+
//                +---> | PREPARING | <--------------------+
//                |     +-----------+                      |
//                |           |                            |
//                |           | Buffer next flight         |
//                |           |                            |
//                |          \|/                           |
//                |     +-----------+                      |
//                |     |  SENDING  |<------------------+  | Send
//                |     +-----------+                   |  | HelloRequest
//        Receive |           |                         |  |
//           next |           | Send flight             |  | or
//         flight |  +--------+                         |  |
//                |  |        | Set retransmit timer    |  | Receive
//                |  |       \|/                        |  | HelloRequest
//                |  |  +-----------+                   |  | Send
//                +--)--|  WAITING  |-------------------+  | ClientHello
//                |  |  +-----------+   Timer expires   |  |
//                |  |         |                        |  |
//                |  |         +------------------------+  |
//        Receive |  | Send           Read retransmit      |
//           last |  | last                                |
//         flight |  | flight                              |
//                |  |                                     |
//               \|/\|/                                    |
//            +-----------+                                |
//            | FINISHED  | -------------------------------+
//            +-----------+
//                 |  /|\
//                 |   |
//                 +---+
//              Read retransmit
//           Retransmit last flight

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 80.08%. Comparing base (602dc71) to head (f356763).

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #646      +/-   ##
==========================================
- Coverage   80.12%   80.08%   -0.04%     
==========================================
  Files         101      101              
  Lines        5353     5328      -25     
==========================================
- Hits         4289     4267      -22     
- Misses        687      690       +3     
+ Partials      377      371       -6     

Flag	Coverage Δ
go	80.11% <ø> (-0.04%)	⬇️
wasm	63.93% <ø> (-0.06%)	⬇️

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[Sean-Der]

@at-wat @hasheddan I’m gonna merge these tonight! I believe they will have zero impact

[at-wat]

Is it expected?

[Sean-Der]

@at-wat sorry I messed up, I merged the other PR before seeing this comment.

Yes I believe so! It is getting retransmitted from the remote now. Before I think it was detecting handshake complete and not doing a rtx.