state machine pic fix to send fin-ack

[lol-fi]

No description provided.

[sethnielson]

There is a potential problem with this. What about the case where two fins are sent? What about the client and server shutting down at about the same time? Both send fins. Do they both send FIN-ACK's or just ACK's?

[lol-fi]

Thinking this through, I think it is fine if they both send fin-acks. This is because the protocol specifies that you send the fin ack after you wait for outstanding data and outstanding acks. So one will send the fin-ack, after recving all outstanding data and acks. Now, the receiver will get the fin-ack and shut down and send the last ack.

The other guy will send their fin ack, but it will go to someone who shut down. As specified by the PRFC, they can just shut down, since it is specified that the other guy would not have sent the fin-ack if there was outstanding data, and there wasn't. So, they will time out waiting for their last ack and shut down anyway.