mac-802_11.cc

802.11的.cc文件

/* -*-	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 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.
 *
 * $Header: /cvsroot/nsnam/ns-2/mac/mac-802_11.cc,v 1.51 2006/01/30 21:27:51 mweigle Exp $
 *
 * Ported from CMU/Monarch's code, nov'98 -Padma.
 * Contributions by:
 *   - Mike Holland
 *   - Sushmita
 */

#include "delay.h"
#include "connector.h"
#include "packet.h"
#include "random.h"
#include "mobilenode.h"

// #define DEBUG 99

#include "arp.h"
#include "ll.h"
#include "mac.h"
#include "mac-timers.h"
#include "mac-802_11.h"
#include "cmu-trace.h"

// Added by Sushmita to support event tracing
#include "agent.h"
#include "basetrace.h"


/* our backoff timer doesn't count down in idle times during a
 * frame-exchange sequence as the mac tx state isn't idle; genreally
 * these idle times are less than DIFS and won't contribute to
 * counting down the backoff period, but this could be a real
 * problem if the frame exchange ends up in a timeout! in that case,
 * i.e. if a timeout happens we've not been counting down for the
 * duration of the timeout, and in fact begin counting down only
 * DIFS after the timeout!! we lose the timeout interval - which
 * will is not the REAL case! also, the backoff timer could be NULL
 * and we could have a pending transmission which we could have
 * sent! one could argue this is an implementation artifact which
 * doesn't violate the spec.. and the timeout interval is expected
 * to be less than DIFS .. which means its not a lot of time we
 * lose.. anyway if everyone hears everyone the only reason a ack will
 * be delayed will be due to a collision => the medium won't really be
 * idle for a DIFS for this to really matter!!
 */

inline void
Mac802_11::checkBackoffTimer()
{
	if(is_idle() && mhBackoff_.paused())
		mhBackoff_.resume(phymib_.getDIFS());
	if(! is_idle() && mhBackoff_.busy() && ! mhBackoff_.paused())
		mhBackoff_.pause();
}

inline void
Mac802_11::transmit(Packet *p, double timeout)
{
	tx_active_ = 1;
	
	if (EOTtarget_) {
		assert (eotPacket_ == NULL);
		eotPacket_ = p->copy();
	}

	/*
	 * If I'm transmitting without doing CS, such as when
	 * sending an ACK, any incoming packet will be "missed"
	 * and hence, must be discarded.
	 */
	if(rx_state_ != MAC_IDLE) {
		//assert(dh->dh_fc.fc_type == MAC_Type_Control);
		//assert(dh->dh_fc.fc_subtype == MAC_Subtype_ACK);
		assert(pktRx_);
		struct hdr_cmn *ch = HDR_CMN(pktRx_);
		ch->error() = 1;        /* force packet discard */
	}

	/*
	 * pass the packet on the "interface" which will in turn
	 * place the packet on the channel.
	 *
	 * NOTE: a handler is passed along so that the Network
	 *       Interface can distinguish between incoming and
	 *       outgoing packets.
	 */
	downtarget_->recv(p->copy(), this);	
	mhSend_.start(timeout);
	mhIF_.start(txtime(p));
}
inline void
Mac802_11::setRxState(MacState newState)
{
	rx_state_ = newState;
	checkBackoffTimer();
}

inline void
Mac802_11::setTxState(MacState newState)
{
	tx_state_ = newState;
	checkBackoffTimer();
}


/* ======================================================================
   TCL Hooks for the simulator
   ====================================================================== */
static class Mac802_11Class : public TclClass {
public:
	Mac802_11Class() : TclClass("Mac/802_11") {}
	TclObject* create(int, const char*const*) {
	return (new Mac802_11());

}
} class_mac802_11;


/* ======================================================================
   Mac  and Phy MIB Class Functions
   ====================================================================== */

PHY_MIB::PHY_MIB(Mac802_11 *parent)
{
	/*
	 * Bind the phy mib objects.  Note that these will be bound
	 * to Mac/802_11 variables
	 */

	parent->bind("CWMin_", &CWMin);
	parent->bind("CWMax_", &CWMax);
	parent->bind("SlotTime_", &SlotTime);
	parent->bind("SIFS_", &SIFSTime);
	parent->bind("PreambleLength_", &PreambleLength);
	parent->bind("PLCPHeaderLength_", &PLCPHeaderLength);
	parent->bind_bw("PLCPDataRate_", &PLCPDataRate);
}

MAC_MIB::MAC_MIB(Mac802_11 *parent)
{
	/*
	 * Bind the phy mib objects.  Note that these will be bound
	 * to Mac/802_11 variables
	 */
	
	parent->bind("RTSThreshold_", &RTSThreshold);
	parent->bind("ShortRetryLimit_", &ShortRetryLimit);
	parent->bind("LongRetryLimit_", &LongRetryLimit);
}

/* ======================================================================
   Mac Class Functions
   ====================================================================== */
Mac802_11::Mac802_11() : 
	Mac(), phymib_(this), macmib_(this), mhIF_(this), mhNav_(this), 
	mhRecv_(this), mhSend_(this), 
	mhDefer_(this), mhBackoff_(this)
{
	
	nav_ = 0.0;
	tx_state_ = rx_state_ = MAC_IDLE;
	tx_active_ = 0;
	eotPacket_ = NULL;
	pktRTS_ = 0;
	pktCTRL_ = 0;		
	cw_ = phymib_.getCWMin();
	ssrc_ = slrc_ = 0;
	// Added by Sushmita
        et_ = new EventTrace();
	
	sta_seqno_ = 1;
	cache_ = 0;
	cache_node_count_ = 0;
	
	// chk if basic/data rates are set
	// otherwise use bandwidth_ as default;
	
	Tcl& tcl = Tcl::instance();
	tcl.evalf("Mac/802_11 set basicRate_");
	if (strcmp(tcl.result(), "0") != 0) 
		bind_bw("basicRate_", &basicRate_);
	else
		basicRate_ = bandwidth_;

	tcl.evalf("Mac/802_11 set dataRate_");
	if (strcmp(tcl.result(), "0") != 0) 
		bind_bw("dataRate_", &dataRate_);
	else
		dataRate_ = bandwidth_;

	bind_bool("bugFix_timer_", &bugFix_timer_);

        EOTtarget_ = 0;
       	bss_id_ = IBSS_ID;
	//printf("bssid in constructor %d\n",bss_id_);
}


int
Mac802_11::command(int argc, const char*const* argv)
{
	if (argc == 3) {
		if (strcmp(argv[1], "eot-target") == 0) {
			EOTtarget_ = (NsObject*) TclObject::lookup(argv[2]);
			if (EOTtarget_ == 0)
				return TCL_ERROR;
			return TCL_OK;
		} else if (strcmp(argv[1], "bss_id") == 0) {
			bss_id_ = atoi(argv[2]);
			return TCL_OK;
		} else if (strcmp(argv[1], "log-target") == 0) { 
			logtarget_ = (NsObject*) TclObject::lookup(argv[2]);
			if(logtarget_ == 0)
				return TCL_ERROR;
			return TCL_OK;
		} else if(strcmp(argv[1], "nodes") == 0) {
			if(cache_) return TCL_ERROR;
			cache_node_count_ = atoi(argv[2]);
			cache_ = new Host[cache_node_count_ + 1];
			assert(cache_);
			bzero(cache_, sizeof(Host) * (cache_node_count_+1 ));
			return TCL_OK;
		} else if(strcmp(argv[1], "eventtrace") == 0) {
			// command added to support event tracing by Sushmita
                        et_ = (EventTrace *)TclObject::lookup(argv[2]);
                        return (TCL_OK);
                }
	}
	return Mac::command(argc, argv);
}

// Added by Sushmita to support event tracing
void Mac802_11::trace_event(char *eventtype, Packet *p) 
{
        if (et_ == NULL) return;
        char *wrk = et_->buffer();
        char *nwrk = et_->nbuffer();
	
        //char *src_nodeaddr =
	//       Address::instance().print_nodeaddr(iph->saddr());
        //char *dst_nodeaddr =
        //      Address::instance().print_nodeaddr(iph->daddr());
	
        struct hdr_mac802_11* dh = HDR_MAC802_11(p);
	
        //struct hdr_cmn *ch = HDR_CMN(p);
	
	if(wrk != 0) {
		sprintf(wrk, "E -t "TIME_FORMAT" %s %2x ",
			et_->round(Scheduler::instance().clock()),
                        eventtype,
                        //ETHER_ADDR(dh->dh_sa)
                        ETHER_ADDR(dh->dh_ta)
                        );
        }
        if(nwrk != 0) {
                sprintf(nwrk, "E -t "TIME_FORMAT" %s %2x ",
                        et_->round(Scheduler::instance().clock()),
                        eventtype,
                        //ETHER_ADDR(dh->dh_sa)
                        ETHER_ADDR(dh->dh_ta)
                        );
        }
        et_->dump();
}

/* ======================================================================
   Debugging Routines
   ====================================================================== */
void
Mac802_11::trace_pkt(Packet *p) 
{
	struct hdr_cmn *ch = HDR_CMN(p);
	struct hdr_mac802_11* dh = HDR_MAC802_11(p);
	u_int16_t *t = (u_int16_t*) &dh->dh_fc;

	fprintf(stderr, "\t[ %2x %2x %2x %2x ] %x %s %d\n",
		*t, dh->dh_duration,
		 ETHER_ADDR(dh->dh_ra), ETHER_ADDR(dh->dh_ta),
		index_, packet_info.name(ch->ptype()), ch->size());
}

void
Mac802_11::dump(char *fname)
{
	fprintf(stderr,
		"\n%s --- (INDEX: %d, time: %2.9f)\n",
		fname, index_, Scheduler::instance().clock());

	fprintf(stderr,
		"\ttx_state_: %x, rx_state_: %x, nav: %2.9f, idle: %d\n",
		tx_state_, rx_state_, nav_, is_idle());

	fprintf(stderr,
		"\tpktTx_: %lx, pktRx_: %lx, pktRTS_: %lx, pktCTRL_: %lx, callback: %lx\n",
		(long) pktTx_, (long) pktRx_, (long) pktRTS_,
		(long) pktCTRL_, (long) callback_);

	fprintf(stderr,
		"\tDefer: %d, Backoff: %d (%d), Recv: %d, Timer: %d Nav: %d\n",
		mhDefer_.busy(), mhBackoff_.busy(), mhBackoff_.paused(),
		mhRecv_.busy(), mhSend_.busy(), mhNav_.busy());
	fprintf(stderr,
		"\tBackoff Expire: %f\n",
		mhBackoff_.expire());
}


/* ======================================================================
   Packet Headers Routines
   ====================================================================== */
inline int
Mac802_11::hdr_dst(char* hdr, int dst )
{
	struct hdr_mac802_11 *dh = (struct hdr_mac802_11*) hdr;
	
       if (dst > -2) {
               if ((bss_id() == ((int)IBSS_ID)) || (addr() == bss_id())) {
                       /* if I'm AP (2nd condition above!), the dh_3a
                        * is already set by the MAC whilst fwding; if
                        * locally originated pkt, it might make sense
                        * to set the dh_3a to myself here! don't know
                        * how to distinguish between the two here - and
                        * the info is not critical to the dst station
                        * anyway!
                        */
                       STORE4BYTE(&dst, (dh->dh_ra));
               } else {
                       /* in BSS mode, the AP forwards everything;
                        * therefore, the real dest goes in the 3rd
                        * address, and the AP address goes in the
                        * destination address
                        */
                       STORE4BYTE(&bss_id_, (dh->dh_ra));
                       STORE4BYTE(&dst, (dh->dh_3a));
               }
       }


       return (u_int32_t)ETHER_ADDR(dh->dh_ra);
}

inline int 
Mac802_11::hdr_src(char* hdr, int src )
{
	struct hdr_mac802_11 *dh = (struct hdr_mac802_11*) hdr;
        if(src > -2)
               STORE4BYTE(&src, (dh->dh_ta));
        return ETHER_ADDR(dh->dh_ta);
}

inline int 
Mac802_11::hdr_type(char* hdr, u_int16_t type)
{
	struct hdr_mac802_11 *dh = (struct hdr_mac802_11*) hdr;
	if(type)
		STORE2BYTE(&type,(dh->dh_body));
	return GET2BYTE(dh->dh_body);
}


/* ======================================================================
   Misc Routines
   ====================================================================== */
inline int
Mac802_11::is_idle()
{
	if(rx_state_ != MAC_IDLE)
		return 0;
	if(tx_state_ != MAC_IDLE)
		return 0;
	if(nav_ > Scheduler::instance().clock())
		return 0;
	
	return 1;
}

void
Mac802_11::discard(Packet *p, const char* why)
{
	hdr_mac802_11* mh = HDR_MAC802_11(p);
	hdr_cmn *ch = HDR_CMN(p);

	/* if the rcvd pkt contains errors, a real MAC layer couldn't
	   necessarily read any data from it, so we just toss it now */
	if(ch->error() != 0) {
		Packet::free(p);
		return;
	}

	switch(mh->dh_fc.fc_type) {
	case MAC_Type_Management:
		drop(p, why);
		return;
	case MAC_Type_Control:
		switch(mh->dh_fc.fc_subtype) {
		case MAC_Subtype_RTS:
			 if((u_int32_t)ETHER_ADDR(mh->dh_ta) ==  (u_int32_t)index_) {
				drop(p, why);
				return;
			}
			/* fall through - if necessary */
		case MAC_Subtype_CTS:
		case MAC_Subtype_ACK:
			if((u_int32_t)ETHER_ADDR(mh->dh_ra) == (u_int32_t)index_) {
				drop(p, why);
				return;
			}
			break;
		default:
			fprintf(stderr, "invalid MAC Control subtype\n");
			exit(1);
		}
		break;
	case MAC_Type_Data:
		switch(mh->dh_fc.fc_subtype) {
		case MAC_Subtype_Data:
			if((u_int32_t)ETHER_ADDR(mh->dh_ra) == \
                           (u_int32_t)index_ ||
                          (u_int32_t)ETHER_ADDR(mh->dh_ta) == \
                           (u_int32_t)index_ ||
                          (u_int32_t)ETHER_ADDR(mh->dh_ra) == MAC_BROADCAST) {
                                drop(p,why);
                                return;
			}
			break;
		default:
			fprintf(stderr, "invalid MAC Data subtype\n");
			exit(1);
		}
		break;
	default:
		fprintf(stderr, "invalid MAC type (%x)\n", mh->dh_fc.fc_type);
		trace_pkt(p);
		exit(1);
	}
	Packet::free(p);
}

void
Mac802_11::capture(Packet *p)
{
	/*
	 * Update the NAV so that this does not screw
	 * up carrier sense.
	 */	
	set_nav(usec(phymib_.getEIFS() + txtime(p)));
	Packet::free(p);
}

void
Mac802_11::collision(Packet *p)
{
	switch(rx_state_) {
	case MAC_RECV:
		setRxState(MAC_COLL);
		/* fall through */
	case MAC_COLL:
		assert(pktRx_);
		assert(mhRecv_.busy());
		/*
		 *  Since a collision has occurred, figure out
		 *  which packet that caused the collision will
		 *  "last" the longest.  Make this packet,
		 *  pktRx_ and reset the Recv Timer if necessary.
		 */
		if(txtime(p) > mhRecv_.expire()) {
			mhRecv_.stop();
			discard(pktRx_, DROP_MAC_COLLISION);
			pktRx_ = p;
			mhRecv_.start(txtime(pktRx_));
		}
		else {
			discard(p, DROP_MAC_COLLISION);
		}
		break;
	default:
		assert(0);
	}
}

void
Mac802_11::tx_resume()
{
	double rTime;
	assert(mhSend_.busy() == 0);
	assert(mhDefer_.busy() == 0);

	if(pktCTRL_) {
		/*
		 *  Need to send a CTS or ACK.
		 */
		mhDefer_.start(phymib_.getSIFS());
	} else if(pktRTS_) {
		if (mhBackoff_.busy() == 0) {
			if (bugFix_timer_) {
				mhBackoff_.start(cw_, is_idle(), 
						 phymib_.getDIFS());
			}
			else {
				rTime = (Random::random() % cw_) * 
					phymib_.getSlotTime();
				mhDefer_.start( phymib_.getDIFS() + rTime);
			}
		}
	} else if(pktTx_) {