dsragent.cc

在Linux下做的QuadTree的程序

	} 
      else if(strcasecmp(argv[1], "mac-addr") == 0) 
	{
	  MAC_id = ID(atoi(argv[2]), ::MAC);
	  route_cache->MAC_id = MAC_id;
	  return TCL_OK;
	}
      
      if( (obj = TclObject::lookup(argv[2])) == 0) 
	{
	  fprintf(stderr, "DSRAgent: %s lookup of %s failed\n", argv[1],
		  argv[2]);
	  return TCL_ERROR;
	}

      if (strcasecmp(argv[1], "log-target") == 0) 
	{
	  logtarget = (Trace*) obj;
	  return route_cache->command(argc, argv);
	}
      else if (strcasecmp(argv[1], "install-tap") == 0) 
	{
	  Mac *m = (Mac*) obj;
	  m->installTap(this);
	  return TCL_OK;
	}

    }
  else if (argc == 4)
    {
      if (strcasecmp(argv[1], "add-ll") == 0) 
	{
	  if( (obj = TclObject::lookup(argv[2])) == 0) {
	    fprintf(stderr, "DSRAgent: %s lookup of %s failed\n", argv[1],
		    argv[2]);
	    return TCL_ERROR;
	  }
	  ll = (NsObject*) obj;
	  if( (obj = TclObject::lookup(argv[3])) == 0) {
	    fprintf(stderr, "DSRAgent: %s lookup of %s failed\n", argv[1],
		    argv[3]);
	    return TCL_ERROR;
	  }
	  ifq = (PriQueue *) obj;
	  return TCL_OK;

	}


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

void
DSRAgent::recv(Packet* packet, Handler*)
  /* handle packets with a MAC destination address of this host, or
     the MAC broadcast addr */
{
  hdr_sr *srh =  (hdr_sr*)packet->access(off_sr_);
  hdr_ip *iph =  (hdr_ip*)packet->access(off_ip_);
  hdr_cmn *cmh =  (hdr_cmn*)packet->access(off_cmn_);

  assert(cmh->size() >= 0);

  SRPacket p(packet, srh);
  p.dest = ID(iph->dst(),::IP);
  p.src = ID(iph->src(),::IP);

  assert(logtarget != 0);

  if (!srh->valid())
    { // this must be an outgoing packet, it doesn't have a SR header on it
      srh->init();		 // give packet an SR header now
      cmh->size() += IP_HDR_LEN; // add on IP header size
      if (verbose)
	trace("S %.9f _%s_ originating %s -> %s",
	      Scheduler::instance().clock(), net_id.dump(), p.src.dump(), 
	      p.dest.dump());
      handlePktWithoutSR(p, false);
      goto done;
    }
  else if (p.dest == net_id || p.dest == IP_broadcast)
    { // this packet is intended for us
      handlePacketReceipt(p);
      goto done;
    }
      
  // should we check to see if it's an error packet we're handling
  // and if so call processBrokenRouteError to snoop
  if (dsragent_snoop_forwarded_errors && srh->route_error())
    {
      processBrokenRouteError(p);
    }

  if (srh->route_request())
    { // propagate a route_request that's not for us
      handleRouteRequest(p);
    }
  else
    { // we're not the intended final recpt, but we're a hop
      handleForwarding(p);
    }


done:
  assert(p.pkt == 0);

  p.pkt = 0;
  return;
}


/*===========================================================================
  handlers for each class of packet
---------------------------------------------------------------------------*/
void
DSRAgent::handlePktWithoutSR(SRPacket& p, bool retry)
  /* obtain a source route to p's destination and send it off.
     this should be a retry if the packet is already in the sendbuffer */
{
  hdr_sr *srh =  (hdr_sr*)p.pkt->access(off_sr_);
  assert(srh->valid());

  if (p.dest == net_id)
    { // it doesn't need a source route, 'cause it's for us
      handlePacketReceipt(p);
      return;
    }

  if (route_cache->findRoute(p.dest, p.route, 1))
    { // we've got a route...
      if (verbose)
	trace("S$hit %.5f _%s_ %s -> %s %s",
	      Scheduler::instance().clock(), net_id.dump(),
	      p.src.dump(), p.dest.dump(), p.route.dump());      
      sendOutPacketWithRoute(p, true);
      return;
    } // end if we have a route
  else
    { // we don't have a route...
      if (verbose) 
	trace("S$miss %.5f _%s_ %s -> %s", 
	      Scheduler::instance().clock(), net_id.dump(), 
	      net_id.dump(), p.dest.dump());

      getRouteForPacket(p, retry);
      return;
    } // end of we don't have a route
}

void
DSRAgent::handlePacketReceipt(SRPacket& p)
  /* Handle a packet destined to us */
{
  hdr_cmn *cmh =  (hdr_cmn*)p.pkt->access(off_cmn_);
  hdr_sr *srh =  (hdr_sr*)p.pkt->access(off_sr_);

  if (srh->route_reply())
    { // we got a route_reply piggybacked on a route_request
      // accept the new source route before we do anything else
      // (we'll send off any packet's we have queued and waiting)
      acceptRouteReply(p);
    }
  
  if (srh->route_request())
    {
      if (dsragent_reply_only_to_first_rtreq  && ignoreRouteRequestp(p)) 
	{ //we only respond to the first route request
	  // we receive from a host 
	  Packet::free(p.pkt);     // drop silently
	  p.pkt = 0;
	  return;
	}
      else
	{ // we're going to process this request now, so record the req_num
	  request_table.insert(p.src, p.src, srh->rtreq_seq());
	  returnSrcRouteToRequestor(p);
	}
    }

  if (srh->route_error())
    { // register the dead route      
      processBrokenRouteError(p);
    }

  /* give the data in the packet to our higher layer (our port dmuxer, most 
   likely) */
  assert(p.dest == net_id || p.dest == MAC_id);
  cmh->size() -= srh->size();	// cut off the SR header 4/7/99 -dam
  srh->valid() = 0;
  cmh->size() -= IP_HDR_LEN;    // cut off IP header size 4/7/99 -dam
  target_->recv(p.pkt, (Handler*)0);
  p.pkt = 0;
}

void
DSRAgent::handleForwarding(SRPacket &p)
  /* forward packet on to next host in source route,
   snooping as appropriate */
{
  hdr_sr *srh =  (hdr_sr*)p.pkt->access(off_sr_);
  hdr_cmn *cmh =  (hdr_cmn*)p.pkt->access(off_cmn_);

  trace("SF %.9f _%s_ --- %d [%s -> %s] %s", 
	Scheduler::instance().clock(), net_id.dump(), cmh->uid(),
	p.src.dump(), p.dest.dump(), srh->dump());

  // first make sure we are the ``current'' host along the source route.
  // if we're not, the previous node set up the source route incorrectly.
  assert(p.route[p.route.index()] == net_id
	 || p.route[p.route.index()] == MAC_id);

  if (p.route.index() >= p.route.length())
    {
      fprintf(stderr,"dfu: ran off the end of a source route\n");
      trace("SDFU:  ran off the end of a source route\n");
      drop(p.pkt, DROP_RTR_ROUTE_LOOP);
      p.pkt = 0;
      // maybe we should send this packet back as an error...
      return;
    }

  // if there's a source route, maybe we should snoop it too
  if (dsragent_snoop_source_routes)
    route_cache->noticeRouteUsed(p.route, Scheduler::instance().clock(), 
				 net_id);

  // sendOutPacketWithRoute will add in the size of the src hdr, so
  // we have to subtract it out here
  struct hdr_cmn *ch = HDR_CMN(p.pkt);
  ch->size() -= srh->size();

  // now forward the packet...
  sendOutPacketWithRoute(p, false);
}

void
DSRAgent::handleRouteRequest(SRPacket &p)
  /* process a route request that isn't targeted at us */
{
  hdr_sr *srh =  (hdr_sr*)p.pkt->access(off_sr_);
  assert (srh->route_request());

  if (ignoreRouteRequestp(p)) 
    {
      if (verbose_srr) 
        trace("SRR %.5f _%s_ dropped %s #%d (ignored)",
              Scheduler::instance().clock(), net_id.dump(), p.src.dump(),
              srh->rtreq_seq());
      Packet::free(p.pkt);  // pkt is a route request we've already processed
      p.pkt = 0;
      return; // drop silently
    }

  // we're going to process this request now, so record the req_num
  request_table.insert(p.src, p.src, srh->rtreq_seq());

  /*  - if it's a Ring 0 search, check the rt$ for a reply and use it if
     possible.  There's not much point in doing Ring 0 search if you're 
     not going to check the cache.  See the comment about turning off all
     reply from cache behavior near the definition of d_r_f_c_o_p (if your 
     workload had really good spatial locality, it might still make 
     sense 'cause your target is probably sitting next to you)
      - if reply from cache is on, check the cache and reply if possible
      - otherwise, just propagate if possible. */
  if ((srh->max_propagation() == 0 || dsragent_reply_from_cache_on_propagating)
      && replyFromRouteCache(p))
    return;			// all done

  // does the orginator want us to propagate?
  if (p.route.length() > srh->max_propagation())
    { 	// no propagation
      if (verbose_srr) 
        trace("SRR %.5f _%s_ dropped %s #%d (prop limit exceeded)",
              Scheduler::instance().clock(), net_id.dump(), p.src.dump(),
              srh->rtreq_seq());
      Packet::free(p.pkt); // pkt isn't for us, and isn't data carrying
      p.pkt = 0;
      return;		
    }

  // can we propagate?
  if (p.route.full())
    { 	// no propagation
      trace("SRR %.5f _%s_ dropped %s #%d (SR full)",
            Scheduler::instance().clock(), net_id.dump(), p.src.dump(),
	    srh->rtreq_seq());
      /* pkt is a rt req, even if data carrying, we don't want to log 
	 the drop using drop() since many nodes could be dropping the 
	 packet in this fashion */
      Packet::free(p.pkt);
      p.pkt = 0;
      return;		
    }

  // add ourselves to the source route
  p.route.appendToPath(net_id);

  if (verbose_srr)
    trace("SRR %.5f _%s_ rebroadcast %s #%d ->%s %s",
          Scheduler::instance().clock(), net_id.dump(), p.src.dump(),
          srh->rtreq_seq(), p.dest.dump(), p.route.dump());

  sendOutPacketWithRoute(p, false);
  return;      
}

/*===========================================================================
  Helpers
---------------------------------------------------------------------------*/
bool
DSRAgent::ignoreRouteRequestp(SRPacket &p)
// should we ignore this route request?
{
  hdr_sr *srh =  (hdr_sr*)p.pkt->access(off_sr_);

  if (request_table.get(p.src) >= srh->rtreq_seq())
    { // we've already processed a copy of this reqest so
      // we should drop the request silently
      return true;
    }
  if (p.route.member(net_id,MAC_id))
    { // we're already on the route, drop silently
      return true;
    }

  if (p.route.full())
    { // there won't be room for us to put our address into
      // the route
      // so drop silently - sigh, so close, and yet so far...
      // Note that since we don't record the req_id of this message yet,
      // we'll process the request if it gets to us on a shorter path
      return true;
    }
  return false;
}


bool
DSRAgent::replyFromRouteCache(SRPacket &p)
  /* - see if can reply to this route request from our cache
     if so, do it and return true, otherwise, return false 
     - frees or hands off p iff returns true */
{
  Path rest_of_route;
  Path complete_route = p.route;

  /* we shouldn't yet be on on the pkt's current source route */
  assert(!p.route.member(net_id, MAC_id));

  // do we have a cached route the target?
  /* XXX what if we have more than 1?  (and one is legal for reply from
     cache and one isn't?) 1/28/97 -dam */
  if (!route_cache->findRoute(p.dest, rest_of_route, 0))
    { // no route => we're done
      return false;
    }

  /* but we should be on on the remainder of the route (and should be at
   the start of the route */
  assert(rest_of_route[0] == net_id || rest_of_route[0] == MAC_id);

  if (rest_of_route.length() + p.route.length() > MAX_SR_LEN)
    return false; // too long to work with...

  // add our suggested completion to the route so far
  complete_route.appendPath(rest_of_route);

  // call compressPath to remove any double backs
  ::compressPath(complete_route);

  if (!complete_route.member(net_id, MAC_id))
    { // we're not on the suggested route, so we can't return it
      return false;
    }

  // if there is any other information piggybacked into the
  // route request pkt, we need to forward it on to the dst
  hdr_cmn *cmh =  (hdr_cmn*)p.pkt->access(off_cmn_);
  hdr_sr *srh =  (hdr_sr*)p.pkt->access(off_sr_);
  int request_seqnum = srh->rtreq_seq();
  
  if (PT_DSR != cmh->ptype()	// there's data