aodv.cc

一个无线自组网aodv路由的扩展版---AOMDV（多径路由协议）。

/* 
   aodv.cc
 */

/* 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.
 * 
 * The original CMU copyright is below. 
 */

/*
Copyright (c) 1997, 1998 Carnegie Mellon University.  All Rights
Reserved. 

Permission to use, copy, modify, and distribute this
software and its documentation is hereby granted (including for
commercial 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 CMU
MONARCH PROJECT ARE EXPERIMENTAL AND ARE KNOWN TO HAVE BUGS, SOME OF
WHICH MAY HAVE SERIOUS CONSEQUENCES. CARNEGIE MELLON PROVIDES THIS
SOFTWARE 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 PARTICULAR
PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY
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 OR
INTELLECTUAL PROPERTY, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
DAMAGE.

Carnegie Mellon encourages (but does not require) users of this
software or intellectual property to return any improvements or
extensions that they make, and to grant Carnegie Mellon the rights to
redistribute these changes without encumbrance.

*/

//#include <ip.h>
//#include <cmu/cmu-trace.h>
//

#include <cmu/aodv/aodv.h>
#include <cmu/aodv/aodv_packet.h>
#include <random.h>


#define min(a,b)        a < b ? a : b
#define max(a,b)        a > b ? a : b
#define CURRENT_TIME    Scheduler::instance().clock()

// #define DEBUG
#ifdef DEBUG
static int extra_route_reply = 0;
static int limit_route_request = 0;
static int route_request = 0;
#endif


/*
  TCL Hooks
*/
static class AODVHeaderClass : public PacketHeaderClass {
public:
        AODVHeaderClass() : PacketHeaderClass("PacketHeader/AODV",
                                              AODV_HDR_LEN) { } 
} class_rtProtoAODV_hdr;

static class AODVclass : public TclClass {
public:
        AODVclass() : TclClass("Agent/rtProto/AODV") {}
        TclObject* create(int argc, const char*const* argv) {
	  assert(argc == 5);
          return (new AODV((nsaddr_t) atoi(argv[4])));
        }
} class_rtProtoAODV;

static void
aodv_rt_failed_callback(Packet *p, void *arg) {
  ((AODV*) arg)->rt_ll_failed(p);
}

int
AODV::command(int argc, const char*const* argv) {
  if(argc == 2) {
  Tcl& tcl = Tcl::instance();
    
    if(strncasecmp(argv[1], "id", 2) == 0) {
      tcl.resultf("%d", index);
      return TCL_OK;
    }
    
    if(strncasecmp(argv[1], "start", 2) == 0) {
      btimer.handle((Event*) 0);

      rqueue.limit_ = send_buffer_size_;
      rqueue.timeout_ = send_buffer_timeout_;

#ifdef DEBUG
  fprintf(stderr, "%s: limit(%d)\ttimeout(%f)\n", __FUNCTION__, rqueue.limit_, rqueue.timeout_);
  fprintf(stderr, "%s(%d): %d\n", __FUNCTION__, index, aomdv_max_paths_);
  fprintf(stderr, "%s(%d): %d\n", __FUNCTION__, index, aomdv_prim_alt_path_len_diff_);
#endif // DEBUG
                
  /*
#ifndef AODV_LINK_LAYER_DETECTION
      htimer.handle((Event*) 0);
      ntimer.handle((Event*) 0);
#endif // LINK LAYER DETECTION
  */

#ifdef AODV_HELLO
      htimer.handle((Event*) 0);
      ntimer.handle((Event*) 0);
#endif // AODV HELLO

      rtimer.handle((Event*) 0);

      return TCL_OK;
     }               
  }
  else if(argc == 3) {
    if(strcmp(argv[1], "index") == 0) {
      index = atoi(argv[2]);
      return TCL_OK;
    }
    else if(strcmp(argv[1], "log-target") == 0) {
      logtarget = (Trace*) TclObject::lookup(argv[2]);
      if(logtarget == 0)
	return TCL_ERROR;
      return TCL_OK;
    }
    else if(strcmp(argv[1], "drop-target") == 0) {
    int stat = rqueue.command(argc,argv);
      if (stat != TCL_OK) return stat;
      return Agent::command(argc, argv);
    }
    else if(strcmp(argv[1], "if-queue") == 0) {
    ifqueue = (PriQueue*) TclObject::lookup(argv[2]);
      
      if(ifqueue == 0)
	return TCL_ERROR;
      return TCL_OK;
    }

}
  return Agent::command(argc, argv);
}

/* 
   Constructor
*/

AODV::AODV(nsaddr_t id) : Agent(PT_AODV),
			  btimer(this), htimer(this), ntimer(this), 
			  rtimer(this), lrtimer(this),
			  rqueue() {
 
  bind("off_AODV_", &off_AODV_);

  send_buffer_size_ = AODV_RTQ_MAX_LEN;
  bind("send_buffer_size_", &send_buffer_size_);

  send_buffer_timeout_ = AODV_RTQ_TIMEOUT;
  bind("send_buffer_timeout_", &send_buffer_timeout_);

#ifdef AOMDV
  aomdv_max_paths_ = 0;
  bind("aomdv_max_paths_", &aomdv_max_paths_);

  aomdv_prim_alt_path_len_diff_ = 0;
  bind("aomdv_prim_alt_path_len_diff_", &aomdv_prim_alt_path_len_diff_);
#endif AOMDV

  index = id;
  seqno = 2;
  bid = 1;

  LIST_INIT(&nbhead);
  LIST_INIT(&bihead);

  logtarget = 0;
  ifqueue = 0;

}

void
AODV::recv(Packet *p, Handler*) {
struct hdr_cmn *ch = HDR_CMN(p);
struct hdr_ip *ih = HDR_IP(p);

 assert(initialized());
 assert(p->incoming == 0);

 if(ch->ptype() == PT_AODV) {
   ih->ttl_ -= 1;
   recvAODV(p);
   return;
 }

 /*
  *  Must be a packet I'm originating...
  */
 if((ih->src_ == index) && (ch->num_forwards() == 0)) {
   assert(DATA_PACKET(ch->ptype()));
 /*
  * Add the IP Header
  */
   ch->size() += IP_HDR_LEN;
#ifdef AOMDV
   ch->aomdv_salvage_count_ = 0;
#endif // AOMDV
   ih->ttl_ = NETWORK_DIAMETER;
 }
 /*
  *  I received a packet that I sent.  Probably
  *  a routing loop.
  */
 else if(ih->src_ == index) {
   drop(p, DROP_RTR_ROUTE_LOOP);
   return;
 }
 /*
  *  Packet I'm forwarding...
  */
 else {
 /*
  *  Check the TTL.  If it is zero, then discard.
  */
   if(--ih->ttl_ == 0) {
     drop(p, DROP_RTR_TTL);
     return;
   }
 }

 rt_resolve(p);

}


void
AODV::recvAODV(Packet *p) {
struct hdr_aodv *ah = HDR_AODV(p);
struct hdr_ip *ih = HDR_IP(p);

 assert(ih->sport_ == RT_PORT);
 assert(ih->dport_ == RT_PORT);

 /*
  * Incoming Packets.
  */
 switch(ah->ah_type) {

 case AODVTYPE_RREQ:
   recvRequest(p);
   break;

 case AODVTYPE_RREP:
   recvReply(p);
   break;

 case AODVTYPE_RERR:
   recvError(p);
   break;

 case AODVTYPE_HELLO:
   recvHello(p);
   break;
        
 default:
   fprintf(stderr, "Invalid AODV type (%x)\n", ah->ah_type);
   exit(1);
 }

}

/*
 * Data packet forwarding
 */
void
AODV::rt_resolve(Packet *p) {
struct hdr_cmn *ch = HDR_CMN(p);
struct hdr_ip *ih = HDR_IP(p);
aodv_rt_entry *rt;

 /*
  *  Set the transmit failure callback.  That
  *  won't change.
  */
 ch->xmit_failure_ = aodv_rt_failed_callback;
 ch->xmit_failure_data_ = (void*) this;

 rt = rtable.rt_lookup(ih->dst_);
 if(rt == 0) {
   rt = rtable.rt_add(ih->dst_);
 }

 /*
  * If the route is up, forward the packet 
  */
	
 if(rt->rt_flags == RTF_UP) {
   forward(rt, p, NO_DELAY);
 }
 /*
  *  if I am the source of the packet, then do a Route Request.
  */
 else if(ih->src_ == index) {
   rqueue.enque(p);
   sendRequest(rt->rt_dst);
 }
 /*
  *	A local repair is in progress. Buffer the packet. 
  */
 else if (rt->rt_flags == RTF_IN_REPAIR) {
   rqueue.enque(p);
 }

 /*
  * I am trying to forward a packet for someone else to which
  * I don't have a route.
  * Drop the packet and send a route error upstream
  */
 else {
 Packet *rerr = Packet::alloc();
 struct hdr_aodv_error *re = HDR_AODV_ERROR(rerr);
 
#ifdef DEBUG
   fprintf(stderr, "%s: sending RERR...\n", __FUNCTION__);
#endif // DEBUG

   assert (rt->rt_flags == RTF_DOWN);
   re->DestCount = 0;
   re->unreachable_dst[re->DestCount] = rt->rt_dst;
   re->unreachable_dst_seqno[re->DestCount] = rt->rt_seqno;
   re->DestCount += 1;
   sendError(rerr, false);

   drop(p, DROP_RTR_NO_ROUTE);
 }
}

void
AODV::forward(aodv_rt_entry *rt, Packet *p, double delay) {
struct hdr_cmn *ch = HDR_CMN(p);
struct hdr_ip *ih = HDR_IP(p);

 if(ih->ttl_ == 0) {

#ifdef DEBUG
  fprintf(stderr, "%s: calling drop()\n", __PRETTY_FUNCTION__);
#endif // DEBUG
 
  drop(p, DROP_RTR_TTL);
  return;
 }

 if (rt) {
   assert(rt->rt_flags == RTF_UP);

   ch->addr_type() = AF_INET;


#ifndef AOMDV

   ch->next_hop_ = rt->rt_nexthop;
   rt->rt_expire = CURRENT_TIME + ACTIVE_ROUTE_TIMEOUT;
   // CHANGE
   if ((ih->src_ != index) && DATA_PACKET(ch->ptype()))
   	rt->rt_error = true;
   // CHANGE 

#else AOMDV

AODV_Path *path = rt->path_find();
   ch->next_hop_ = path->nexthop;
   path->expire = CURRENT_TIME + ACTIVE_ROUTE_TIMEOUT;
   // CHANGE
   if ((ih->src_ != index) && DATA_PACKET(ch->ptype()))
   	rt->rt_error = true;
   // CHANGE 

#endif AOMDV

 }
 else { // if it is a broadcast packet
   assert(ch->ptype() == PT_AODV);
   assert(ih->dst_ == (nsaddr_t) IP_BROADCAST);
   ch->addr_type() = AF_NONE;
 }

 if (ih->dst_ == (nsaddr_t) IP_BROADCAST) {
 // If it is a broadcast packet
   assert(rt == 0);
   /*
    *  Jitter the sending of broadcast packets by 10ms
    */
   Scheduler::instance().schedule(target_, p,
      				   0.01 * Random::uniform());
 }
 else { // Not a broadcast packet 

   // CHANGE
   ch->xmit_failure_ = aodv_rt_failed_callback;
   ch->xmit_failure_data_ = (void*) this;
   // CHANGE


   if(delay > 0.0) {
     Scheduler::instance().schedule(target_, p, delay);
   }
   else {
   // Not a broadcast packet, no delay, send immediately
     Scheduler::instance().schedule(target_, p, 0.);
   }
 }

}

/*
 * Route discovery
 */

void
AODV::sendRequest(nsaddr_t dst) {
// Allocate a RREQ packet 
Packet *p = Packet::alloc();
struct hdr_cmn *ch = HDR_CMN(p);
struct hdr_ip *ih = HDR_IP(p);
struct hdr_aodv_request *rq = HDR_AODV_REQUEST(p);
aodv_rt_entry *rt = rtable.rt_lookup(dst);

	assert(rt);

 	if (rt->rt_flags == RTF_UP) {
   		Packet::free((Packet *)p);
   		return;
 	}

 	if (rt->rt_req_timeout > CURRENT_TIME) {
   		Packet::free((Packet *)p);
   		return;
 	}

 	// rt_req_cnt is the no. of times we did network-wide broadcast

 	if (rt->rt_req_cnt > RREQ_RETRIES) {
   		rt->rt_req_timeout = 0.0;
		rt->rt_req_last_ttl = 0;
   		rt->rt_req_cnt = 0;

 	Packet *buf_pkt;
   		while ((buf_pkt = rqueue.deque(rt->rt_dst))) {
       			drop(buf_pkt, DROP_RTR_QTIMEOUT);
   		}
   		Packet::free((Packet *)p);
   		return;
 	}

	rt->rt_expire = 0;


	// expanding ring search: dynamic ttl evaluation
	int new_ttl = 0;
	if (rt->rt_req_last_ttl == 0) {
	// we are about to start a new route discovery
		if (rt->rt_last_hop_count == 0) new_ttl = TTL_START;
		else new_ttl = rt->rt_last_hop_count + TTL_INCREMENT;
	}
	else {
	// we are already in the midst of a route discovery
		assert (rt->rt_req_last_ttl > rt->rt_last_hop_count);
		if (rt->rt_req_last_ttl < TTL_THRESHOLD) new_ttl = rt->rt_req_last_ttl + TTL_INCREMENT;
		else new_ttl = NETWORK_DIAMETER;
	}

	if (new_ttl >= NETWORK_DIAMETER) {
	// network-wide broadcast
		new_ttl = NETWORK_DIAMETER;
		rt->rt_req_cnt += 1;
	}

	ih->ttl_ = new_ttl;
	rt->rt_req_last_ttl = new_ttl;

 	rt->rt_req_timeout = 2.0 * (double) ih->ttl_ * PerHopTime(rt); 
 	// PerHopTime is the roundtrip time per hop for route requests.
 	// The factor 2.0 is just to be safe .. SRD 5/22/99
 	if (rt->rt_req_cnt > 0)
   		rt->rt_req_timeout *= rt->rt_req_cnt;
 	// Also note that we are making timeouts to be larger if we have 
 	// done network wide broadcast before. 
 	rt->rt_req_timeout += CURRENT_TIME;

 	// Fill out the RREQ packet 
 	// ch->uid() = 0;
 	ch->ptype() = PT_AODV;
 	ch->size() = IP_HDR_LEN + rq->size();
 	ch->iface() = -2;
 	ch->error() = 0;
 	ch->addr_type() = AF_NONE;

 	ih->src_ = index;
 	ih->dst_ = IP_BROADCAST;
 	ih->sport_ = RT_PORT;
 	ih->dport_ = RT_PORT;
	
 	// Fill up some more fields. 
 	rq->rq_type = AODVTYPE_RREQ;
 	rq->rq_bcast_id = bid++;
 	rq->rq_hop_count = 0;
 	rq->rq_dst = dst;
 	rq->rq_dst_seqno = (rt ? rt->rt_seqno : 0);
 	rq->rq_src = index;