void starttimer(int AorB,float increment)
// AorB; /* A or B is trying to stop timer */
{
struct event *q;
struct event *evptr;
////char *malloc();
if (TRACE>2)
printf(" START TIMER: starting timer at %f\n",time_local);
/* be nice: check to see if timer is already started, if so, then warn */
/* for (q=evlist; q!=NULL && q->next!=NULL; q = q->next) */
for (q=evlist; q!=NULL ; q = q->next)
if ( (q->evtype==TIMER_INTERRUPT && q->eventity==AorB) ) {
printf("Warning: attempt to start a timer that is already started\n");
return;
}
/* create future event for when timer goes off */
evptr = (struct event *)malloc(sizeof(struct event));
evptr->evtime = time_local + increment;
evptr->evtype = TIMER_INTERRUPT;
evptr->eventity = AorB;
insertevent(evptr);
}
void generate_next_arrival()
{
double x,log(),ceil();
struct event *evptr;
if (TRACE>2)
printf(" GENERATE NEXT ARRIVAL: creating new arrival\n");
x = lambda*jimsrand()*2; /* x is uniform on [0,2*lambda] */
/* having mean of lambda */
evptr = (struct event *)malloc(sizeof(struct event));
evptr->evtime = time + x;
evptr->evtype = FROM_LAYER5;
if (BIDIRECTIONAL && (jimsrand()>0.5) )
evptr->eventity = B;
else
evptr->eventity = A;
insertevent(evptr);
}
/************************** TOLAYER2 ***************/
void toLayer2( struct RoutePacket packet ) {
struct RoutePacket *mypktptr;
struct event *evptr, *q;
float lastime;
int i;
// be nice: check if source and destination id's are reasonable
if (packet.sourceid < 0 || packet.sourceid > NumberOfNodes ) {
printf("WARNING: illegal source id in your packet, ignoring packet!\n");
return;
}
if (packet.destid < 0 || packet.destid > NumberOfNodes ) {
printf("WARNING: illegal dest id in your packet, ignoring packet!\n");
return;
}
if (packet.sourceid == packet.destid) {
printf("WARNING: source and destination id's the same, ignoring packet!\n");
return;
}
if (ConnectCosts[packet.sourceid][packet.destid] == INFINITY) {
printf("WARNING: source and destination not connected, ignoring packet!\n");
return;
}
// make a copy of the packet student just gave me since he/she may decide
// to do something with the packet after we return back to him/her *
mypktptr = (struct RoutePacket *) malloc(sizeof(struct RoutePacket));
mypktptr->sourceid = packet.sourceid;
mypktptr->destid = packet.destid;
for (i = 0; i < NumberOfNodes; i++)
mypktptr->mincost[i] = packet.mincost[i];
if (TraceLevel>2) {
printf(" TOLAYER2: source: %d, dest: %d\n costs:",
mypktptr->sourceid, mypktptr->destid);
for (i=0; i < NumberOfNodes; i++)
printf("%d ",mypktptr->mincost[i]);
printf("\n");
}
// create future event for arrival of packet at the other side
evptr = (struct event *)malloc(sizeof(struct event));
evptr->evtype = FROM_LAYER2; // packet will pop out in layer3
evptr->eventity = packet.destid; // event occurs at other entity
evptr->rtpktptr = mypktptr; // save ptr to my copy of packet
// finally, compute the arrival time of packet at the other end.
// medium can not reorder, so make sure packet arrives between 1 and 10
// time units after the latest arrival time of packets
// currently in the medium on their way to the destination
lastime = clocktime;
for (q=evlist; q!=NULL ; q = q->next)
if ( (q->evtype == FROM_LAYER2 && q->eventity == evptr->eventity) )
lastime = q->evtime;
evptr->evtime = lastime + 2.*GetRandomNumber();
if (TraceLevel>2)
printf(" TOLAYER2: scheduling arrival on other side\n");
insertevent(evptr);
} // End of toLayer2
//////////////////////////////////////////////////////////////////////
// init()
// This routine initializes lots of parameters and variables used
// throughout the simulation.
//////////////////////////////////////////////////////////////////////
void init() {
int i, j, found;
float sum, avg;
struct event *evptr;
FILE *fp; // Used for the configuration file
srand(9999); // init random number generator
sum = 0.0; // test random number generator for students
for (i = 0; i < 1000; i++)
sum = sum + GetRandomNumber(); // should be uniform in [0,1]
avg = sum/1000.0;
if (avg < 0.25 || avg > 0.75) {
printf("It is likely that random number generation on your machine\n" );
printf("is different from what this emulator expects. Please take\n");
printf("a look at the routine jimsrand() in the emulator code. Sorry. \n");
exit(0);
}
clocktime = 0.0; // initialize time to 0.0
// Load in node information from the configuration file
fp = fopen( filename, "r" );
if ( fp == NULL ) {
printf("Unable to open the configuration file %s\n", filename );
exit(0);
}
// We only expect ONE value on the first line, but guard against
// someone having MORE than one number.
found = fscanf( fp, "%d, %d", &NumberOfNodes, &i );
if ( found != 1 ) { // We expect 1 number on the first line
printf( "First line of file should contain number of nodes\n");
exit(0);
}
if (NumberOfNodes < 2 || NumberOfNodes > MAX_NODES ) {
printf( "Error reading %s configuration file - number of nodes\n", filename );
exit(0);
}
// Initialize the array so illegal nodes have infinite cost
for ( i = 0; i < MAX_NODES; i++ )
for ( j = 0; j < MAX_NODES; j++ )
ConnectCosts[i][j] = INFINITY;
// Now load in the nodes and costs from the file
for ( i = 0; i < NumberOfNodes; i++ ) {
found = fscanf( fp, "%d, %d, %d, %d, %d, %d, %d, %d, %d, %d",
&ConnectCosts[i][0], &ConnectCosts[i][1], &ConnectCosts[i][2],
&ConnectCosts[i][3], &ConnectCosts[i][4], &ConnectCosts[i][5],
&ConnectCosts[i][6], &ConnectCosts[i][7], &ConnectCosts[i][8],
&ConnectCosts[i][9] );
if ( found != NumberOfNodes ) {
printf("We expected to see %d node costs on this line but found %d\n",
NumberOfNodes, found );
exit(0);
}
}
fclose(fp); // We're all done
// Call each of the nodes so they can initialize their stuff
rtinit0();
rtinit1();
rtinit2();
rtinit3();
/* initialize future link changes */
if (LINKCHANGES == 1) {
evptr = (struct event *)malloc(sizeof(struct event));
evptr->evtime = 10000.0;
evptr->evtype = LINK_CHANGE;
evptr->eventity = -1;
evptr->rtpktptr = NULL;
insertevent(evptr);
evptr = (struct event *)malloc(sizeof(struct event));
evptr->evtype = LINK_CHANGE;
evptr->evtime = 20000.0;
evptr->rtpktptr = NULL;
insertevent(evptr);
}
} // End of init()
/************************** TOLAYER3 ***************/
void tolayer3(int AorB,struct pkt packet)
{
struct pkt *mypktptr;
struct event *evptr,*q;
////char *malloc();
float lastime, x, jimsrand();
int i;
ntolayer3++;
/* simulate losses: */
if (jimsrand() < lossprob) {
nlost++;
if (TRACE>0)
printf(" TOLAYER3: packet being lost\n");
return;
}
/* make a copy of the packet student just gave me since he/she may decide */
/* to do something with the packet after we return back to him/her */
mypktptr = (struct pkt *)malloc(sizeof(struct pkt));
mypktptr->seqnum = packet.seqnum;
mypktptr->acknum = packet.acknum;
mypktptr->checksum = packet.checksum;
for (i=0; i<20; i++)
mypktptr->payload[i] = packet.payload[i];
if (TRACE>2) {
printf(" TOLAYER3: seq: %d, ack %d, check: %d ", mypktptr->seqnum,
mypktptr->acknum, mypktptr->checksum);
for (i=0; i<20; i++)
printf("%c",mypktptr->payload[i]);
printf("\n");
}
/* create future event for arrival of packet at the other side */
evptr = (struct event *)malloc(sizeof(struct event));
evptr->evtype = FROM_LAYER3; /* packet will pop out from layer3 */
evptr->eventity = (AorB+1) % 2; /* event occurs at other entity */
evptr->pktptr = mypktptr; /* save ptr to my copy of packet */
/* finally, compute the arrival time of packet at the other end.
medium can not reorder, so make sure packet arrives between 1 and 10
time units after the latest arrival time of packets
currently in the medium on their way to the destination */
lastime = time_local;
/* for (q=evlist; q!=NULL && q->next!=NULL; q = q->next) */
for (q=evlist; q!=NULL ; q = q->next)
if ( (q->evtype==FROM_LAYER3 && q->eventity==evptr->eventity) )
lastime = q->evtime;
evptr->evtime = lastime + 1 + 9*jimsrand();
/* simulate corruption: */
if (jimsrand() < corruptprob) {
ncorrupt++;
if ( (x = jimsrand()) < .75)
mypktptr->payload[0]='Z'; /* corrupt payload */
else if (x < .875)
mypktptr->seqnum = 999999;
else
mypktptr->acknum = 999999;
if (TRACE>0)
printf(" TOLAYER3: packet being corrupted\n");
}
if (TRACE>2)
printf(" TOLAYER3: scheduling arrival on other side\n");
insertevent(evptr);
}
