obp/obp/pkg/netinet/tcp-timer.fth

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\ Hypervisor Software File: tcp-timer.fth
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id: @(#)tcp-timer.fth 1.1 04/09/07
purpose: TCP timer management
copyright: Copyright 2004 Sun Microsystems, Inc.  All Rights Reserved
copyright: Use is subject to license terms.

headerless

/timer instance buffer:  tcp-fast-timer         \ 200 ms timer
/timer instance buffer:  tcp-slow-timer         \ 500 ms timer

: tcp-start-fasttimer ( -- )  tcp-fast-timer d# 200 set-timer ;
: tcp-start-slowtimer ( -- )  tcp-slow-timer d# 500 set-timer ;

\ Start tracking fast and slow timeouts.
: tcp-start-timers ( -- )
   tcp-start-fasttimer  tcp-start-slowtimer             ( )
;

\ Delayed ACK processing routine called once every 200 ms
: tcp-do-delacks ( inpcb -- )
   inpcb>tcb  dup tcb-flags@  TF_DELACK and if          ( tcb )
      dup TF_ACKNOW tcb-set-flags                       ( tcb )
      dup tcp-output                                    ( tcb )
   then  drop                                           ( )
;

\ TCP protocol timeout routine called every 500 ms. Check timers
\ in all TCBs and causes FSM actions if timers have expired.
: tcp-process-timeouts ( inpcb -- )
   inpcb>tcb                                            ( tcb )
   dup >tcbt-rexmit timer-expired?  if                  ( tcb )
      tcp-retransmit exit                               ( )
   then                                                 ( tcb )
   dup >tcbt-connect timer-expired?  if                 ( tcb )
      ETIMEDOUT tcp-drop exit                           ( )
   then  drop                                           ( )
;

\ Handle TCP timer events
: tcp-do-timer-events ( -- )
   tcp-fast-timer timer-expired?  if                            ( )
      tcp-start-fasttimer                                       ( )
      tcp-inpcb-list ['] tcp-do-delacks queue-iterate           ( )
   then                                                         ( )
   tcp-slow-timer timer-expired?  if                            ( )
      tcp-start-slowtimer                                       ( )
      tcp-inpcb-list ['] tcp-process-timeouts queue-iterate     ( )
   then                                                         ( )
;

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