Add local and remote CID to state

Adds local and remote CID to state, but does not serialize them. CIDs
should be renogotiated on session resumption.

Signed-off-by: Daniel Mangum <[email protected]>

Author: hasheddan

state.go

@@ -27,6 +27,20 @@ type State struct {
 	IdentityHint          []byte
 	SessionID             []byte
 
+	// Connection Identifiers must be negotiated afresh on session resumption.
+	// https://datatracker.ietf.org/doc/html/rfc9146#name-the-connection_id-extension
+
+	// localConnectionID is the locally generated connection ID that is expected
+	// to be received from the remote endpoint.
+	// For a server, this is the connection ID sent in ServerHello.
+	// For a client, this is the connection ID sent in the ClientHello.
+	localConnectionID []byte
+	// remoteConnectionID is the connection ID that the remote endpoint
+	// specifies should be sent.
+	// For a server, this is the connection ID received in the ClientHello.
+	// For a client, this is the connection ID received in the ServerHello.
+	remoteConnectionID []byte
+
 	isClient bool
 
 	preMasterSecret      []byte