tcp-sink.cc

运行于linux上的CIMS套件

/* -*-	Mode:C++; c-basic-offset:8; tab-width:8; indent-tabs-mode:t -*- */
/*
 * Copyright (c) 1991-1997 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 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: /usr/src/mash/repository/vint/ns-2/tcp-sink.cc,v 1.41 2000/04/15 03:09:06 sfloyd Exp $ (LBL)";
#endif

#include "flags.h"
#include "ip.h"
#include "tcp-sink.h"

#define SINKSEQ
//SHK
FILE *seqfile;
FILE *tcpseq2;

static class TcpSinkClass : public TclClass {
public:
	TcpSinkClass() : TclClass("Agent/TCPSink") {}
	TclObject* create(int, const char*const*) {
		return (new TcpSink(new Acker));
	}
} class_tcpsink;

Acker::Acker() : next_(0), maxseen_(0), ecn_unacked_(0), ts_to_echo_(0)
{
	memset(seen_, 0, sizeof(seen_));
}

void Acker::reset() 
{
	next_ = 0;
	maxseen_ = 0;
	memset(seen_, 0, sizeof(seen_));
}	

void Acker::update_ts(int seqno, double ts)
{
	if (ts >= ts_to_echo_ && seqno <= next_)
		ts_to_echo_ = ts;
}

// returns number of bytes that can be "delivered" to application
// also updates the receive window (i.e. next_, maxseen, and seen_ array)
int Acker::update(int seq, int numBytes)
{
	bool just_marked_as_seen = FALSE;
	is_dup_ = FALSE;
	// start by assuming the segment hasn't been received before
	if (numBytes <= 0)
		printf("Error, received TCP packet size <= 0\n");
	int numToDeliver = 0;
	if (seq - next_ >= MWM) {
		// next_ is next packet expected; MWM is the maximum
		// window size minus 1; if somehow the seqno of the
		// packet is greater than the one we're expecting+MWM,
		// then ignore it.
		return 0;
	}

	if (seq > maxseen_) {
		// the packet is the highest one we've seen so far
		int i;
		for (i = maxseen_ + 1; i < seq; ++i)
			seen_[i & MWM] = 0;
		// we record the packets between the old maximum and
		// the new max as being "unseen" i.e. 0 bytes of each
		// packet have been received
		maxseen_ = seq;
		seen_[maxseen_ & MWM] = numBytes;
		// store how many bytes have been seen for this packet
		seen_[(maxseen_ + 1) & MWM] = 0;
		// clear the array entry for the packet immediately
		// after this one
		just_marked_as_seen = TRUE;
		// necessary so this packet isn't confused as being a duplicate
	}
	int next = next_;
	if (seq < next) {
		// Duplicate packet case 1: the packet is to the left edge of
		// the receive window; therefore we must have seen it
		// before
#ifdef DEBUGDSACK
		printf("%f\t Received duplicate packet %d\n",Scheduler::instance().clock(),seq);
#endif
		is_dup_ = TRUE;
	}

	if (seq >= next && seq <= maxseen_) {
		// next is the left edge of the recv window; maxseen_
		// is the right edge; execute this block if there are
		// missing packets in the recv window AND if current
		// packet falls within those gaps

		if (seen_[seq & MWM] && !just_marked_as_seen) {
		// Duplicate case 2: the segment has already been
		// recorded as being received (AND not because we just
		// marked it as such)
			is_dup_ = TRUE;
#ifdef DEBUGDSACK
			printf("%f\t Received duplicate packet %d\n",Scheduler::instance().clock(),seq);
#endif
		}
		seen_[seq & MWM] = numBytes;
		// record the packet as being seen
		while (seen_[next & MWM]) {
			// this loop first gets executed if seq==next;
			// i.e., this is the next packet in order that
			// we've been waiting for.  the loop sets how
			// many bytes we can now deliver to the
			// application, due to this packet arriving
			// (and the prior arrival of any segments
			// immediately to the right)
			numToDeliver += seen_[next & MWM];
			++next;
		}
		next_ = next;
		// store the new left edge of the window
	}
	return numToDeliver;
}

TcpSink::TcpSink(Acker* acker) : Agent(PT_ACK), acker_(acker), save_(NULL), 
         recvBytes_(0)  /* Wan */
{
#ifdef SINKSEQ
//SHK
        seqfile = fopen("seqfile", "w");
        tcpseq2 = fopen("tcpseq2", "w");
#endif
	/*
	 * maxSackBlocks_ does wierd tracing things.
	 * don't make it delay-bound yet.
	 */
#if defined(TCP_DELAY_BIND_ALL) && 0
#else /* ! TCP_DELAY_BIND_ALL */
	bind("maxSackBlocks_", &max_sack_blocks_); // used only by sack
#endif /* TCP_DELAY_BIND_ALL */
        /* Wan: add a tcl bound variable */
        bind("recvBytes", &recvBytes_);
}

void
TcpSink::delay_bind_init_all()
{
        delay_bind_init_one("packetSize_");
        delay_bind_init_one("ts_echo_bugfix_");
        delay_bind_init_one("generateDSacks_"); // used only by sack
	delay_bind_init_one("RFC2581_immediate_ack_");
#if defined(TCP_DELAY_BIND_ALL) && 0
        delay_bind_init_one("maxSackBlocks_");
#endif /* TCP_DELAY_BIND_ALL */

	Agent::delay_bind_init_all();
}

int
TcpSink::delay_bind_dispatch(const char *varName, const char *localName, TclObject *tracer)
{
        if (delay_bind(varName, localName, "packetSize_", &size_, tracer)) return TCL_OK;
        if (delay_bind_bool(varName, localName, "ts_echo_bugfix_", &ts_echo_bugfix_, tracer)) return TCL_OK;
        if (delay_bind_bool(varName, localName, "generateDSacks_", &generate_dsacks_, tracer)) return TCL_OK;
        if (delay_bind_bool(varName, localName, "RFC2581_immediate_ack_", &RFC2581_immediate_ack_, tracer)) return TCL_OK;
#if defined(TCP_DELAY_BIND_ALL) && 0
        if (delay_bind(varName, localName, "maxSackBlocks_", &max_sack_blocks_, tracer)) return TCL_OK;
#endif /* TCP_DELAY_BIND_ALL */

        return Agent::delay_bind_dispatch(varName, localName, tracer);
}

void Acker::append_ack(hdr_cmn*, hdr_tcp*, int) const
{
}

void Acker::update_ecn_unacked(int value)
{
	ecn_unacked_ = value;
}

int TcpSink::command(int argc, const char*const* argv)
{
	if (argc == 2) {
		if (strcmp(argv[1], "reset") == 0) {
			reset();
			return (TCL_OK);
		}
	}
	return (Agent::command(argc, argv));
}

void TcpSink::reset() 
{
	acker_->reset();	
	save_ = NULL;
#ifdef SINKSEQ
        fclose(seqfile);
#endif
}

void TcpSink::ack(Packet* opkt)
{
	Packet* npkt = allocpkt();
	// opkt is the "old" packet that was received
	// npkt is the "new" packet being constructed (for the ACK)
	double now = Scheduler::instance().clock();
	hdr_flags *sf;

	hdr_tcp *otcp = hdr_tcp::access(opkt);
	hdr_tcp *ntcp = hdr_tcp::access(npkt);
	// get the tcp headers
	ntcp->seqno() = acker_->Seqno();
#ifdef SINKSEQ
     //fprintf(seqfile, "tcpseq:%d  ack:%d\n",otcp->seqno(),  ntcp->seqno());
     fprintf(tcpseq2, "%f %d\n",Scheduler::instance().clock(), ntcp->seqno());
#endif
	// get the cumulative sequence number to put in the ACK; this
	// is just the left edge of the receive window - 1
	ntcp->ts() = now;
	// timestamp the packet

	if (ts_echo_bugfix_)  /* TCP/IP Illustrated, Vol. 2, pg. 870 */
		ntcp->ts_echo() = acker_->ts_to_echo();
	else
		ntcp->ts_echo() = otcp->ts();
	// echo the original's time stamp

	hdr_ip* oip = (hdr_ip*)opkt->access(off_ip_);
	hdr_ip* nip = (hdr_ip*)npkt->access(off_ip_);
	// get the ip headers
	nip->flowid() = oip->flowid();
	// copy the flow id
	
	hdr_flags* of = (hdr_flags*)opkt->access(off_flags_);
	hdr_flags* nf = (hdr_flags*)npkt->access(off_flags_);
	if (save_ != NULL) 
		sf = (hdr_flags*)save_->access(off_flags_);
		// Look at delayed packet being acked. 
	if ( (save_ != NULL && sf->cong_action()) || of->cong_action() ) 
		// Sender has responsed to congestion. 
		acker_->update_ecn_unacked(0);
	if ( (save_ != NULL && sf->ect() && sf->ce())  || 
			(of->ect() && of->ce()) )
		// New report of congestion.  
		acker_->update_ecn_unacked(1);
	if ( (save_ != NULL && sf->ect()) || of->ect() )
		// Set EcnEcho bit.  
		nf->ecnecho() = acker_->ecn_unacked();
	if (!of->ect() && of->ecnecho() ||
		(save_ != NULL && !sf->ect() && sf->ecnecho()) ) 
		 // This is the negotiation for ECN-capability.
		 // We are not checking for of->cong_action() also. 
		 // In this respect, this does not conform to the 
		 // specifications in the internet draft 
		nf->ecnecho() = 1;
	acker_->append_ack((hdr_cmn*)npkt->access(off_cmn_),
			   ntcp, otcp->seqno());
	add_to_ack(npkt);
	// the above function is used in TcpAsymSink
	
	send(npkt, 0);
	// send it
}

void TcpSink::add_to_ack(Packet*)
{
	return;
}

void TcpSink::recv(Packet* pkt, Handler*)
{
	int numToDeliver;
	int numBytes = ((hdr_cmn*)pkt->access(off_cmn_))->size();
	// number of bytes in the packet just received
	hdr_tcp *th = hdr_tcp::access(pkt);
	acker_->update_ts(th->seqno(),th->ts());
	// update the timestamp to echo
	
      	numToDeliver = acker_->update(th->seqno(), numBytes);
	// update the recv window; figure out how many in-order-bytes
	// (if any) can be removed from the window and handed to the
	// application
	if (numToDeliver)
		recvBytes(numToDeliver);
	// send any packets to the application
      	ack(pkt);
	// ACK the packet
	Packet::free(pkt);
	// remove it from the system
}

/* Added by Wan: */
void TcpSink::recvBytes(int bytes)
{
        double now = Scheduler::instance().clock();
        recvBytes_ += bytes;
}

static class DelSinkClass : public TclClass {
public:
	DelSinkClass() : TclClass("Agent/TCPSink/DelAck") {}
	TclObject* create(int, const char*const*) {
		return (new DelAckSink(new Acker));
	}
} class_delsink;