/*Copyright (c) 1997, 1998 Carnegie Mellon University.  All RightsReserved. Permission to use, copy, modify, and distribute thissoftware and its documentation is hereby granted (including forcommercial or for-profit use), provided that both the copyright notice and this permission notice appear in all copies of the software, derivative works, or modified versions, and any portions thereof, and that both notices appear in supporting documentation, and that credit is given to Carnegie Mellon University in all publications reporting on direct or indirect use of this code or its derivatives.ALL CODE, SOFTWARE, PROTOCOLS, AND ARCHITECTURES DEVELOPED BY THE CMUMONARCH PROJECT ARE EXPERIMENTAL AND ARE KNOWN TO HAVE BUGS, SOME OFWHICH MAY HAVE SERIOUS CONSEQUENCES. CARNEGIE MELLON PROVIDES THISSOFTWARE OR OTHER INTELLECTUAL PROPERTY IN ITS ``AS IS'' CONDITION,AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULARPURPOSE ARE DISCLAIMED. IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITYBE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, ORCONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OFSUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; ORBUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCEOR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE ORINTELLECTUAL PROPERTY, EVEN IF ADVISED OF THE POSSIBILITY OF SUCHDAMAGE.Carnegie Mellon encourages (but does not require) users of thissoftware or intellectual property to return any improvements orextensions that they make, and to grant Carnegie Mellon the rights to redistribute these changes without encumbrance.The AODV code developed by the CMU/MONARCH group was optimized and tuned by Samir Das and Mahesh Marina, University of Cincinnati. The work was partially done in Sun Microsystems.*/#include <assert.h>#include <cmu-trace.h>#include <aodv/aodv_rqueue.h>#define CURRENT_TIME    Scheduler::instance().clock()#define QDEBUG/*  Packet Queue used by AODV.*/aodv_rqueue::aodv_rqueue() {  head_ = tail_ = 0;  len_ = 0;  limit_ = AODV_RTQ_MAX_LEN;  timeout_ = AODV_RTQ_TIMEOUT;}voidaodv_rqueue::enque(Packet *p) {struct hdr_cmn *ch = HDR_CMN(p); /*  * Purge any packets that have timed out.  */ purge();  p->next_ = 0; ch->ts_ = CURRENT_TIME + timeout_; if (len_ == limit_) { Packet *p0 = remove_head();	// decrements len_   assert(p0);   if(HDR_CMN(p0)->ts_ > CURRENT_TIME) {     drop(p0, DROP_RTR_QFULL);   }   else {     drop(p0, DROP_RTR_QTIMEOUT);   } }  if(head_ == 0) {   head_ = tail_ = p; } else {   tail_->next_ = p;   tail_ = p; } len_++;#ifdef QDEBUG   verifyQueue();#endif // QDEBUG}                Packet*aodv_rqueue::deque() {Packet *p; /*  * Purge any packets that have timed out.  */ purge(); p = remove_head();#ifdef QDEBUG verifyQueue();#endif // QDEBUG return p;}Packet*aodv_rqueue::deque(nsaddr_t dst) {Packet *p, *prev; /*  * Purge any packets that have timed out.  */ purge(); findPacketWithDst(dst, p, prev); assert(p == 0 || (p == head_ && prev == 0) || (prev->next_ == p)); if(p == 0) return 0; if (p == head_) {   p = remove_head(); } else if (p == tail_) {   prev->next_ = 0;   tail_ = prev;   len_--; } else {   prev->next_ = p->next_;   len_--; }#ifdef QDEBUG verifyQueue();#endif // QDEBUG return p;}char aodv_rqueue::find(nsaddr_t dst) {Packet *p, *prev;  	 findPacketWithDst(dst, p, prev); if (0 == p)   return 0; else   return 1;}		/*  Private Routines*/Packet*aodv_rqueue::remove_head() {Packet *p = head_;         if(head_ == tail_) {   head_ = tail_ = 0; } else {   head_ = head_->next_; } if(p) len_--; return p;}voidaodv_rqueue::findPacketWithDst(nsaddr_t dst, Packet*& p, Packet*& prev) {    p = prev = 0;  for(p = head_; p; p = p->next_) {	  //		if(HDR_IP(p)->dst() == dst) {	       if(HDR_IP(p)->daddr() == dst) {      return;    }    prev = p;  }}voidaodv_rqueue::verifyQueue() {Packet *p, *prev = 0;int cnt = 0; for(p = head_; p; p = p->next_) {   cnt++;   prev = p; } assert(cnt == len_); assert(prev == tail_);}/*voidaodv_rqueue::purge() {Packet *p; while((p = head_) && HDR_CMN(p)->ts_ < CURRENT_TIME) {   // assert(p == remove_head());        p = remove_head();        drop(p, DROP_RTR_QTIMEOUT); }}*/boolaodv_rqueue::findAgedPacket(Packet*& p, Packet*& prev) {    p = prev = 0;  for(p = head_; p; p = p->next_) {    if(HDR_CMN(p)->ts_ < CURRENT_TIME) {      return true;    }    prev = p;  }  return false;}voidaodv_rqueue::purge() {Packet *p, *prev; while ( findAgedPacket(p, prev) ) { 	assert(p == 0 || (p == head_ && prev == 0) || (prev->next_ == p)); 	if(p == 0) return; 	if (p == head_) {   		p = remove_head(); 	} 	else if (p == tail_) {   		prev->next_ = 0;   		tail_ = prev;   		len_--; 	} 	else {   		prev->next_ = p->next_;   		len_--; 	}#ifdef QDEBUG 	verifyQueue();#endif // QDEBUG	p = prev = 0; }}