anchor.diff:                  ;; Remote have sended SYN+ACK and waiting for ACK
                   (setf (tcp-connection-state connection) :established
                         (tcp-connection-r-next connection) (logand (1+ seq) #xFFFFFFFF))
  -                (tcp4-send-packet connection ack (tcp-connection-r-next connection) nil))
  +                (tcp4-send-packet connection ack (tcp-connection-r-next connection) nil)
  +                ;; Cancel retransmit. FIXME: This ACK might need to be retransmitted.
  +                (disarm-retransmit-timer connection)
  +                (disarm-timeout-timer connection))
                  ((logtest flags +tcp4-flag-syn+)
                   ;; Simultaneous open
                   (setf (tcp-connection-state connection) :syn-received
                         (tcp-connection-r-next connection) (logand (1+ seq) #xFFFFFFFF))
                   (tcp4-send-packet connection ack (tcp-connection-r-next connection) nil
  -                                  :ack-p t :syn-p t))
  +                                  :ack-p t :syn-p t)
  +                ;; Cancel retransmit. FIXME: This SYN/ACK might need to be retransmitted.
  +                (disarm-retransmit-timer connection)
  +                (disarm-timeout-timer connection))
                  (t
                   ;; Aborting connection
                   (tcp4-send-packet connection ack seq nil :rst-p t)
  -                (setf (tcp-connection-state connection) :connection-aborted)
  +                (setf (tcp-connection-state connection) :closed)
  +                (setf (tcp-connection-pending-error connection)
  +                      (make-condition 'connection-aborted
  +                                      :host (tcp-connection-remote-ip connection)
  +                                      :port (tcp-connection-remote-port connection)))
                   (detach-tcp-connection connection))))
           (:syn-received
            ;; Pasive open
  
positive.code:            (data-length (- end (+ start header-length))))
        (when (logtest flags +tcp4-flag-rst+)
          ;; Remote have sended RST , aborting connection
          (setf (tcp-connection-state connection) :connection-aborted)
          (detach-tcp-connection connection))
        (case (tcp-connection-state connection)
          (:syn-sent
  
negative.code:     :last-ack
      :fin-wait-1
      :fin-wait-2
      :closing))
  
  (deftype tcp-port-number ()
    '(unsigned-byte 16))
  