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/* -*- Mode:C++; c-basic-offset:8; tab-width:8; indent-tabs-mode:t -*- */
/*
* Copyright (c) 1994 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:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the Computer Systems
* Engineering Group at Lawrence Berkeley Laboratory.
* 4. Neither the name of the University nor of the Laboratory may be used
* to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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.
*/
#ifndef lint
static const char rcsid[] =
"@(#) $Header: /cvsroot/nsnam/ns-2/queue/drop-tail.cc,v 1.17 2004/10/28 23:35:37 haldar Exp $ (LBL)";
#endif
#include "drop-tail.h"
static class DropTailClass : public TclClass {
public:
DropTailClass() : TclClass("Queue/DropTail") {}
TclObject* create(int, const char*const*) {
return (new DropTail);
}
} class_drop_tail;
void DropTail::reset()
{
Queue::reset();
}
int
DropTail::command(int argc, const char*const* argv)
{
if (argc==2) {
if (strcmp(argv[1], "printstats") == 0) {
print_summarystats();
return (TCL_OK);
}
if (strcmp(argv[1], "shrink-queue") == 0) {
shrink_queue();
return (TCL_OK);
}
}
if (argc == 3) {
if (!strcmp(argv[1], "packetqueue-attach")) {
delete q_;
if (!(q_ = (PacketQueue*) TclObject::lookup(argv[2])))
return (TCL_ERROR);
else {
pq_ = q_;
return (TCL_OK);
}
}
}
return Queue::command(argc, argv);
}
/*
* drop-tail
*/
void DropTail::enque(Packet* p)
{
if (summarystats) {
Queue::updateStats(qib_?q_->byteLength():q_->length());
}
int qlimBytes = qlim_ * mean_pktsize_;
if ((!qib_ && (q_->length() + 1) >= qlim_) ||
(qib_ && (q_->byteLength() + hdr_cmn::access(p)->size()) >= qlimBytes)){
// if the queue would overflow if we added this packet...
if (drop_front_) { /* remove from head of queue */
q_->enque(p);
Packet *pp = q_->deque();
drop(pp);
} else {
drop(p);
}
} else {
q_->enque(p);
}
}
//AG if queue size changes, we drop excessive packets...
void DropTail::shrink_queue()
{
int qlimBytes = qlim_ * mean_pktsize_;
if (debug_)
printf("shrink-queue: time %5.2f qlen %d, qlim %d\n",
Scheduler::instance().clock(),
q_->length(), qlim_);
while ((!qib_ && q_->length() > qlim_) ||
(qib_ && q_->byteLength() > qlimBytes)) {
if (drop_front_) { /* remove from head of queue */
Packet *pp = q_->deque();
drop(pp);
} else {
Packet *pp = q_->tail();
q_->remove(pp);
drop(pp);
}
}
}
Packet* DropTail::deque()
{
if (summarystats && &Scheduler::instance() != NULL) {
Queue::updateStats(qib_?q_->byteLength():q_->length());
}
return q_->deque();
}
void DropTail::print_summarystats()
{
//double now = Scheduler::instance().clock();
printf("True average queue: %5.3f", true_ave_);
if (qib_)
printf(" (in bytes)");
printf(" time: %5.3f\n", total_time_);
}
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