anchor.diff:  (defparameter *netmangler-force-local-retransmit* nil
     "If true, then all data segments will be initially dropped
   and forced to be sent from the retransmit queue.")
  +(defparameter *netmangler-iss* nil
  +  "Force the ISS to this value.
  +Set to a value near 2^32 to test SND sequence number wrapping.")
   
   (defvar *tcp-connections* nil)
   (defvar *tcp-connection-lock* (mezzano.supervisor:make-mutex "TCP connection list"))
  
positive.code:            (when (tcp-listener-backlog listener)
               (incf (tcp-listener-n-pending-connections listener)))
             (let* ((irs (ub32ref/be packet (+ start +tcp4-header-sequence-number+)))
                    (iss (random #x100000000))
                    (connection (make-instance 'tcp-connection
                                               :state :syn-received
                                               :local-port local-port
  
negative.code:   (let* ((interface (nth-value 1 (mezzano.network.ip:ipv4-route ip)))
           (source-address (mezzano.network.ip:ipv4-interface-address interface))
           (source-port (allocate-local-tcp-port source-address ip port))
           (iss (or *netmangler-iss*
                    (random #x100000000)))
           (connection (make-instance 'tcp-connection
                                      :state :syn-sent
                                      :local-port source-port
  