Open Mash Cross Reference
mash/tcl/megafor/al-megafor.tcl

   # al-megafor.tcl --
   #
   #       FIXME: This file needs a description here.
   #
   # Copyright (c) 1997-2002 The Regents of the University of California.
   # All rights reserved.
   #
   # Redistribution and use in source and binary forms, with or without
   # modification, are permitted provided that the following conditions are met:
  #
  # A. Redistributions of source code must retain the above copyright notice,
  #    this list of conditions and the following disclaimer.
  # B. Redistributions in binary form must reproduce the above copyright notice,
  #    this list of conditions and the following disclaimer in the documentation
  #    and/or other materials provided with the distribution.
  # C. Neither the names of the copyright holders nor the names of its
  #    contributors may be used to endorse or promote products derived from this
  #    software without specific prior written permission.
  #
  # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS''
  # AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  # ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR
  # ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  # DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  # SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  # CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  # OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  #
  # @(#) $Header: /usr/mash/src/repository/mash/mash-1/tcl/megafor/al-megafor.tcl,v 1.16 2002/02/03 04:27:42 lim Exp $
  
  import AnnounceListenManager/AS Timer/Adaptive/ConstBW
  
  # AnnounceListenManager for soft state gateway, a generic forwarder for
  # announce/listen traffic, used in AS1 so that clients without multicast can
  # connect to the system.
  # Author: Elan Amir
  # Status: alpha
  Class AnnounceListenManager/AS/SSG -superclass AnnounceListenManager/AS
  
  # An agent creates a manager and passes itself as "agent"
  AnnounceListenManager/AS/SSG instproc init { agent spec bw {srv_inst {}}} {
          $self next $spec $bw ssg
          $self set agent_ $agent
          $self instvar srv_inst_ newtb_ oldtb_
  
          set f [$self get_option newTBFrac]
          set newtb_ [new TokenBucket/SSG $self [expr $bw*$f]]
          $newtb_ start
          set oldtb_ [new TokenBucket/SSG $self [expr $bw*(1-$f)]]
          $oldtb_ start
          set srv_inst_ $srv_inst
  }
  
  AnnounceListenManager/AS/SSG public destroy {} {
          $self instvar newtb_ oldtb_
  
          delete $newtb_
          delete $oldtb_
          $self next
  }
  
  # If a death message arrives, throw it out.  Otherwise, pass the message to the agent
  AnnounceListenManager/AS/SSG instproc recv_msg { atype aspec addr srv_name srv_loc srv_inst ssg_port msg } {
          if { $srv_name == "DEATH" } {
                  return
          }
          $self instvar agent_
          $agent_ recv_msg $self $atype $aspec $addr $srv_name $srv_loc $srv_inst $ssg_port "$msg"
  }
  
  AnnounceListenManager/AS/SSG instproc register args {
  }
  
  AnnounceListenManager/AS/SSG instproc unregister { atype aspec addr srv_name srv_inst msg } {
          $self instvar agent_
          eval $agent_ unregister $aspec
  }
  
  #
  # We enqueue messages from the gateways here.  Since the gateway messages
  # never change, a unique identifier for the message is the agent specification
  # (aspec).  Thus we can identify if we have seen a given message easily by
  # keying on aspec.
  #
  AnnounceListenManager/AS/SSG instproc enqueue { aspec msgtext } {
          $self instvar newtb_ oldtb_ q_
  
          if {![info exists q_($aspec)] || $q_($aspec) != $msgtext} {
                  # new message
                  $newtb_ add $msgtext
          } else {
                  $oldtb_ add $msgtext
          }
          set q_($aspec) $msgtext
  }
  
  AnnounceListenManager/AS/SSG instproc remove_agent { aspec } {
         $self instvar q_
         if [info exists q_($aspec)] {
                 unset q_($aspec)
         }
 }
 
 # A TokenBucket for use with a soft state gateway
 # Author: Elan Amir
 Class TokenBucket/SSG -superclass Timer/Adaptive/ConstBW
 
 TokenBucket/SSG public init { al bw } {
         $self next $bw
 
         $self instvar bw_ q_ qlen_ al_ nsrcs_
         set q_ {}
         set qlen_ 8
         set al_ $al
         $self update_nsrcs 1
 }
 
 TokenBucket/SSG private timeout {} {
         $self instvar al_ q_
         if { $q_ != "" } {
                 set len [$al_ announce [lindex $q_ 0]]
                 $self sample_size $len
                 set q_ [lrange $q_ 1 end]
         }
 }
 
 TokenBucket/SSG public add { msg } {
         $self instvar q_ qlen_
         if { [llength $q_] > $qlen_ } {
                 return
         }
         # FIXME Do we want the aspec as well?
         lappend q_ $msg
 }