implementation-notes.txt

Designing the QUIC processor:

Client-Starting:
- on start connection:
	- Send a first handshake message in Client Initial packet.
        - Move to Client-Handshake-Start

Server-IDLE:
- if received Client Initial:
	- Check the version number.
		If incorrect, send version negotiation, move back to Server Idle. No context created.
	- If correct but client is not verified, may send Stateless Retry.
	- If correct, commit to version, proceed with handshake. Context is created there.
		Send handshake message as Server Clear Text.
		Depending on status of negotiation, move to Server-Handshake progress or 
		Server Ready.
		If server ready, get 1-RTT keys.
	

Client-Handshake-Start:
- if receive Version Negotiation:
	- Find an adequate version number.
	- If none exists, fail.
	- If OK, commit to that. Repeat the handshake packet as Client Initial, with correct version and 
	  incremented packet number. Remain in Client-Handshake-Start.

- if receive Stateless Retry:
	- Verify that PN & CN are echoes of Initial Message.
	- Treat it as handshake message (carries Hello Retry).
	- Extract Address Token if any, and include them in the handshake (how?).
        - Send new handshake packet as Client Initial. Increment PN, etc.
        - Remain in Client-Handshake-Start.

Client Handshake Start or Client Handshake progress:
- if receive Server Clear text:
	- Note CN as server CN associated with connection. (should remain consistent.)
	- Treat as handshake message.
	- (Start using this for all new messages. Really? What if the handshake is an error? How do
		we detect that there is spoofing in progress?)
	- Send Handshake Reply as Client Clear text.
	- If handshake complete:
		Move to Client-Handshake-Complete.
		Obtain 1-RTT key.
		Packets will now be sent encrypted.
		STREAM0 frame copied in multiple packets for reliability (until ack).
- On timer: repeat last message.

Server-Handshake-Progress:
	Expect Client Clear text.
	Based on negotiation state, move to Server-Handshake progress or Server Ready.
	Handshake response if any goes to Server Clear Text.
		If server ready, get 1-RTT keys.



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Frame processing:
- If restricted state (clear text), only accept STREAM0, ACK, PAD.
- In 0-RTT, accept STREAM-N. Stream 0 does not make sense. ACK does not make sense.
- Established state, accept anything. (Including Stateless Reset).
====
Close the connection:
- Send CONNECTION CLOSE Frame.