anchor.diff:                  (setf (tcp-connection-state connection) :connection-aborted)
                   (detach-tcp-connection connection))))
           (:syn-received
  +         ;; Pasive open
            (cond ((and (eql flags +tcp4-flag-ack+)
                        (eql seq (tcp-connection-r-next connection))
                        (eql ack (tcp-connection-s-next connection)))
  +                ;; Remote have sended ACK , connection established
                   (setf (tcp-connection-state connection) :established))
                  ((and (logtest flags +tcp4-flag-syn+)
                        (eql ack (1- (tcp-connection-s-next connection))))
  +                ;; Ignore duplicated SYN packets
                   (format t "TCP: Ignore duplicated syn packets."))
                  (t
                   ;; Aborting connection
  
positive.code:          ;; Not much to do here, just waiting for the application to accept or decline new connection.
           )
          (:syn-sent
           (cond ((and (logtest flags +tcp4-flag-ack+)
                       (logtest flags +tcp4-flag-syn+)
                       (eql ack (tcp-connection-s-next connection)))
  
negative.code:                           ;; Simultaneous close
                            (setf (tcp-connection-state connection) :closing)))
                       ((logtest flags +tcp4-flag-ack+)
                        ;; Remote saw our FIN
                        (setf (tcp-connection-state connection) :fin-wait-2))))
               (tcp4-receive-data connection data-length end header-length packet seq start :fin-wait-1)))
          (:fin-wait-2
  