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/* -*- Mode:C++; c-basic-offset:8; tab-width:8; indent-tabs-mode:t -*- */
/*
* Copyright (c) 1997 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 Daedalus Research
* Group at the University of California Berkeley.
* 4. Neither the name of the University nor of the Research Group 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.
*
* Contributed by the Daedalus Research Group, U.C.Berkeley
* http://daedalus.cs.berkeley.edu
*
* $Header: /cvsroot/nsnam/ns-2/tcp/tcp-int.cc,v 1.15 2000/09/01 03:04:07 haoboy Exp $
*/
/*
* We separate TCP functionality into two parts: that having to do with
* providing a reliable, ordered byte-stream service, and that having to do with
* congestion control and loss recovery. The former is done on a per-connection
* basis and is implemented as part of IntTcpAgent ("integrated TCP"). The
* latter is done in an integrated fashion across multiple TCP connections, and
* is implemented as part of TcpSessionAgent ("TCP session"). TcpSessionAgent is
* derived from CorresHost ("correspondent host"), which keeps track of the
* state of all TCP (TCP/Int) connections to a host that it is corresponding
* with.
*
* The motivation for this separation of functionality is to make an ensemble of
* connection more well-behaved than a set of independent TCP connections.
* The packet loss rate is cut down and the chances of losses being recovered
* via data-driven techniques (rather than via timeouts) is improved. At the
* same time, we do not introduce any unnecessary coupling between the
* logically-independent byte-streams that the set of connections represents.
* This is in contrast to the coupling that is inherent in the multiplexing at
* the application layer of multiple byte-streams onto a single TCP connection.
*/
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include "packet.h"
#include "ip.h"
#include "tcp.h"
#include "flags.h"
#include "nilist.h"
#include "tcp-int.h"
#include "chost.h"
#include "tcp-session.h"
#include "random.h"
Islist<TcpSessionAgent> TcpSessionAgent::sessionList_;
static class IntTcpClass : public TclClass {
public:
IntTcpClass() : TclClass("Agent/TCP/Int") {}
TclObject* create(int, const char*const*) {
return (new IntTcpAgent());
}
} class_tcp_int;
IntTcpAgent::IntTcpAgent() : TcpAgent(), slink(),
session_(0), closecwTS_(0), lastTS_(-1), count_(0),
wt_(1), wndIncSeqno_(0), num_thresh_dupack_segs_(0)
{
bind("rightEdge_", &rightEdge_);
bind("uniqTS_", &uniqTS_);
bind("winInc_", &winInc_);
bind("winMult_", &winMult_);
}
int
IntTcpAgent::command(int argc, const char*const* argv)
{
Tcl& tcl = Tcl::instance();
if (argc == 3) {
if (!strcmp(argv[1], "setwt")) {
if (!session_)
createTcpSession();
session_->set_weight(this,atoi(argv[2]));
return (TCL_OK);
}
}
else if (argc == 2) {
if (!strcmp(argv[1], "session")) {
if (!session_)
createTcpSession();
tcl.resultf("%s", session_->name());
return (TCL_OK);
}
}
return (TcpAgent::command(argc,argv));
}
/*
* Update the ack information and reset the timer. RTT update is done in
* TcpSessionAgent.
*/
void
IntTcpAgent::newack(Packet* pkt)
{
hdr_tcp *tcph = hdr_tcp::access(pkt);
last_ack_ = tcph->seqno();
highest_ack_ = last_ack_;
if (t_seqno_ < last_ack_ + 1)
t_seqno_ = last_ack_ + 1;
/* if the connection is done, call finish() */
if ((highest_ack_ >= curseq_-1) && !closed_) {
closed_ = 1;
finish();
}
}
void
IntTcpAgent::recv(Packet *pkt, Handler *)
{
hdr_tcp *tcph = hdr_tcp::access(pkt);
int amt_data_acked = 0;
if (tcph->seqno() > last_ack_) {
amt_data_acked = tcph->seqno() - last_ack_;
newack(pkt);
}
session_->recv(this, pkt, amt_data_acked);
}
void
IntTcpAgent::createTcpSession()
{
Tcl& tcl = Tcl::instance();
tcl.evalf("%s set node_", name());
tcl.evalf("%s createTcpSession %d", tcl.result(), daddr());
Islist_iter<TcpSessionAgent> session_iter(TcpSessionAgent::sessionList_);
TcpSessionAgent *cur;
while ((cur = session_iter()) != NULL) {
if (cur->addr()/256 == addr() && cur->daddr() == daddr()) {
session_ = cur;
break;
}
}
if (!session_) {
printf("In IntTcpAgent::createTcpSession(): failed\n");
abort();
}
session_->add_agent(this, size_, winMult_, winInc_, ssthresh_);
}
void
IntTcpAgent::output(int seqno, int reason)
{
Packet *pkt = allocpkt();
hdr_tcp *tcph = hdr_tcp::access(pkt);
tcph->seqno() = seqno;
tcph->ts() = Scheduler::instance().clock();
tcph->ts_echo() = ts_peer_;
tcph->reason() = reason;
session_->setflags(pkt);
int bytes = hdr_cmn::access(pkt)->size();
/* call helper function to fill in additional fields */
output_helper(pkt);
++ndatapack_;
ndatabytes_ += bytes;
send(pkt, 0);
if (seqno == curseq_ && seqno > maxseq_)
idle(); // Tell application I have sent everything so far
if (seqno > maxseq_) {
maxseq_ = seqno;
}
else {
++nrexmitpack_;
nrexmitbytes_ += bytes;
}
if (wndIncSeqno_ == 0)
wndIncSeqno_ = maxseq_;
}
/*
* Unlike in other flavors of TCP, IntTcpAgent does not decide when to send
* packets and how many of them to send. That decision is made by
* TcpSessionAgent. So send_much() does little more than defer to
* TcpSessionAgent.
*/
void
IntTcpAgent::send_much(int force, int reason, int /*maxburst*/)
{
if (!session_)
createTcpSession();
if (!force && delsnd_timer_.status() == TIMER_PENDING)
return;
if (overhead_ && !force) {
delsnd_timer_.resched(Random::uniform(overhead_));
return;
}
session_->send_much(this, force,reason);
}
/*
* Send one new packet.
*/
void
IntTcpAgent::send_one(int sessionSeqno)
{
int dst_addr = daddr();
int dst_port = dport();
int sport = port();
if (!session_)
createTcpSession();
/*
* XXX We assume that the session layer has already made sure that
* we have data to send.
*/
output(t_seqno_++);
session_->add_pkts(size_, t_seqno_ - 1, sessionSeqno,
dst_addr, dst_port, sport, lastTS_, this);
}
/*
* open up the congestion window
*/
void
IntTcpAgent::opencwnd()
{
session_->opencwnd(size_, this);
}
/*
* close down the congestion window
*/
void
IntTcpAgent::closecwnd(int how)
{
session_->closecwnd(how, this);
}
Segment *
IntTcpAgent::rxmit_last(int reason, int seqno, int sessionSeqno, double /*ts*/)
{
session_->agent_rcov(this);
/*
* XXX kludge -- IntTcpAgent is not supposed to deal with
* rtx timer
*/
session_->reset_rtx_timer(1,0);
output(seqno, reason);
daddr_ = daddr();
dport_ = dport();
sport_ = port();
return (session_->add_pkts(size_, seqno, sessionSeqno, daddr_,
dport_, sport_, lastTS_, this));
return NULL;
}
unsigned long output_helper_count=0;
double last_clock=0;
void
IntTcpAgent::output_helper(Packet *p)
{
double now = Scheduler::instance().clock();
output_helper_count++;
last_clock = now;
hdr_tcp *tcph = hdr_tcp::access(p);
/* This is to make sure that we get unique times for each xmission */
while (uniqTS_ && now <= lastTS_) {
now += 0.000001; // something arbitrarily small
}
lastTS_ = now;
tcph->ts() = now;
/* if this is a fast start pkt and not a retransmission, mark it */
if (session_->fs_pkt() && tcph->seqno() > maxseq_)
hdr_flags::access(p)->fs_ = 1;
return;
}
int
IntTcpAgent::data_left_to_send() {
return (curseq_ > t_seqno_);
}
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