DV Routing Lab

Lab Video:

http://www.youtube.com/watch?v=Ic1zpIBN534&feature=youtu.be

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DV.h

/* a rtpkt is the packet sent from one routing update process to
another via the call tolayer3() */
struct rtpkt {
int sourceid; /* id of sending router sending this pkt */
int destid; /* id of router to which pkt being sent
(must be an immediate neighbor) */
int mincost[4]; /* min cost to node 0 … 3 */
};

struct distance_table
{
int costs[4][4];
};

void tolayer2(struct rtpkt packet);

// Node Prototypes
void rtinit0();
void rtinit1();
void rtinit2();
void rtinit3();

void rtupdate0(struct rtpkt *rcvdpkt);
void rtupdate1(struct rtpkt *rcvdpkt);
void rtupdate2(struct rtpkt *rcvdpkt);
void rtupdate3(struct rtpkt *rcvdpkt);

void linkhandler0(int linkid, int newcost);
void linkhandler1(int linkid, int newcost);

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DV.CPP

// DV.cpp : Defines the entry point for the console application.
//

#include “stdafx.h”
#include <stdio.h>
#include <stdlib.h>
#include “DV.h”

#define LINKCHANGES 1
/* ******************************************************************
Programming assignment 3: implementing distributed, asynchronous,
distance vector routing.

THIS IS THE MAIN ROUTINE. IT SHOULD NOT BE TOUCHED AT ALL BY STUDENTS!

**********************************************************************/

 
int TRACE = 1; /* for my debugging */
int YES = 1;
int NO = 0;

void creatertpkt(struct rtpkt *initrtpkt,int srcid,int destid,int mincosts[])
{
int i;
initrtpkt->sourceid = srcid;
initrtpkt->destid = destid;
for (i=0; i<4; i++)
initrtpkt->mincost[i] = mincosts[i];
}
/*****************************************************************
***************** NETWORK EMULATION CODE STARTS BELOW ***********
The code below emulates the layer 2 and below network environment:
– emulates the tranmission and delivery (with no loss and no
corruption) between two physically connected nodes
– calls the initializations routines rtinit0, etc., once before
beginning emulation

THERE IS NOT REASON THAT ANY STUDENT SHOULD HAVE TO READ OR UNDERSTAND
THE CODE BELOW. YOU SHOLD NOT TOUCH, OR REFERENCE (in your code) ANY
OF THE DATA STRUCTURES BELOW. If you’re interested in how I designed
the emulator, you’re welcome to look at the code – but again, you should have
to, and you defeinitely should not have to modify
******************************************************************/

struct event {
float evtime; /* event time */
int evtype; /* event type code */
int eventity; /* entity where event occurs */
struct rtpkt *rtpktptr; /* ptr to packet (if any) assoc w/ this event */
struct event *prev;
struct event *next;
};
struct event *evlist = NULL; /* the event list */

/* possible events: */
#define FROM_LAYER2 2
#define LINK_CHANGE 10

float clocktime = 0.000;

void insertevent(struct event *p);

 

void init() /* initialize the simulator */
{
int i;
float sum, avg;
float jimsrand();
struct event *evptr;

printf(“Enter TRACE:”);
scanf_s(“%d”,&TRACE);

srand(9999); /* init random number generator */
sum = 0.0; /* test random number generator for students */
for (i=0; i<1000; i++)
sum=sum+jimsrand(); /* jimsrand() should be uniform in [0,1] */
avg = (float)(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 */
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);
}

}

/****************************************************************************/
/* jimsrand(): return a float in range [0,1]. The routine below is used to */
/* isolate all random number generation in one location. We assume that the*/
/* system-supplied rand() function return an int in therange [0,mmm] */
/****************************************************************************/
float jimsrand()
{
double mmm = RAND_MAX; /* largest int – MACHINE DEPENDENT!!!!!!!! */
float x; /* individual students may need to change mmm */
x = (float)(rand()/mmm); /* x should be uniform in [0,1] */
return(x);
}

/********************* EVENT HANDLINE ROUTINES *******/
/* The next set of routines handle the event list */
/*****************************************************/

void insertevent(struct event *p)
{
struct event *q,*qold;

if (TRACE>3) {
printf(” INSERTEVENT: time is %lf\n”,clocktime);
printf(” INSERTEVENT: future time will be %lf\n”,p->evtime);
}
q = evlist; /* q points to header of list in which p struct inserted */
if (q==NULL) { /* list is empty */
evlist=p;
p->next=NULL;
p->prev=NULL;
}
else {
for (qold = q; q !=NULL && p->evtime > q->evtime; q=q->next)
qold=q;
if (q==NULL) { /* end of list */
qold->next = p;
p->prev = qold;
p->next = NULL;
}
else if (q==evlist) { /* front of list */
p->next=evlist;
p->prev=NULL;
p->next->prev=p;
evlist = p;
}
else { /* middle of list */
p->next=q;
p->prev=q->prev;
q->prev->next=p;
q->prev=p;
}
}
}

void printevlist()
{
struct event *q;
printf(“————–\nEvent List Follows:\n”);
for(q = evlist; q!=NULL; q=q->next) {
printf(“Event time: %f, type: %d entity: %d\n”,q->evtime,q->evtype,q->eventity);
}
printf(“————–\n”);
}
/************************** TOLAYER2 ***************/
void tolayer2(struct rtpkt packet)
{
struct rtpkt *mypktptr;
struct event *evptr, *q;
float jimsrand(),lastime;
int i;

int connectcosts[4][4];

/* initialize by hand since not all compilers allow array initilization */
connectcosts[0][0]=0; connectcosts[0][1]=1; connectcosts[0][2]=3;
connectcosts[0][3]=7;
connectcosts[1][0]=1; connectcosts[1][1]=0; connectcosts[1][2]=1;
connectcosts[1][3]=999;
connectcosts[2][0]=3; connectcosts[2][1]=1; connectcosts[2][2]=0;
connectcosts[2][3]=2;
connectcosts[3][0]=7; connectcosts[3][1]=999; connectcosts[3][2]=2;
connectcosts[3][3]=0;

/* be nice: check if source and destination id’s are reasonable */
if (packet.sourceid<0 || packet.sourceid >3) {
printf(“WARNING: illegal source id in your packet, ignoring packet!\n”);
return;
}
if (packet.destid<0 || packet.destid >3) {
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] == 999) {
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 rtpkt *) malloc(sizeof(struct rtpkt));
mypktptr->sourceid = packet.sourceid;
mypktptr->destid = packet.destid;
for (i=0; i<4; i++)
mypktptr->mincost[i] = packet.mincost[i];
if (TRACE>2) {
printf(” TOLAYER2: source: %d, dest: %d\n costs:”,
mypktptr->sourceid, mypktptr->destid);
for (i=0; i<4; 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 from 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 = (float)(lastime + 2.*jimsrand());
if (TRACE>2)
printf(” TOLAYER2: scheduling arrival on other side\n”);
insertevent(evptr);
}

 
int _tmain(int argc, _TCHAR* argv[])

{
struct event *eventptr;

init();

while (1) {

eventptr = evlist; /* get next event to simulate */
if (eventptr==NULL)
goto terminate;
evlist = evlist->next; /* remove this event from event list */
if (evlist!=NULL)
evlist->prev=NULL;
if (TRACE>1) {
printf(“MAIN: rcv event, t=%.3f, at %d”,
eventptr->evtime,eventptr->eventity);
if (eventptr->evtype == FROM_LAYER2 ) {
printf(” src:%2d,”,eventptr->rtpktptr->sourceid);
printf(” dest:%2d,”,eventptr->rtpktptr->destid);
printf(” contents: %3d %3d %3d %3d\n”,
eventptr->rtpktptr->mincost[0], eventptr->rtpktptr->mincost[1],
eventptr->rtpktptr->mincost[2], eventptr->rtpktptr->mincost[3]);
}
}
clocktime = eventptr->evtime; /* update time to next event time */
if (eventptr->evtype == FROM_LAYER2 ) {
if (eventptr->eventity == 0)
rtupdate0(eventptr->rtpktptr);
else if (eventptr->eventity == 1)
rtupdate1(eventptr->rtpktptr);
else if (eventptr->eventity == 2)
rtupdate2(eventptr->rtpktptr);
else if (eventptr->eventity == 3)
rtupdate3(eventptr->rtpktptr);
else { printf(“Panic: unknown event entity\n”); exit(0); }
}
else if (eventptr->evtype == LINK_CHANGE ) {
if (clocktime<10001.0) {
linkhandler0(1,20);
linkhandler1(0,20);
}
else {
linkhandler0(1,1);
linkhandler1(0,1);
}
}
else
{ printf(“Panic: unknown event type\n”); exit(0); }
if (eventptr->evtype == FROM_LAYER2 )
free(eventptr->rtpktptr); /* free memory for packet, if any */
free(eventptr); /* free memory for event struct */
}

terminate:
printf(“\nSimulator terminated at t=%f, no packets in medium\n”, clocktime);
}

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The Nodes are very Similar, see video above for differences, posted below is only node 0

#include “stdafx.h”
#include “DV.h”
extern int TRACE;
extern int YES;
extern int NO;

int connectcosts0[4] = { 0, 1, 3, 7};//costs to other nodes

static distance_table dt;
/* students to write the following two routines, and maybe some others */

void rtinit0()
{
struct rtpkt rtpacket;
// for all destinations y in N:
for(int j=0;j<4;j++)
for(int k=0;k<4;k++) dt.costs[j][k] = 999;
dt.costs[0][0] = connectcosts0[0];
dt.costs[0][1] = connectcosts0[1];
dt.costs[0][2] = connectcosts0[2];
dt.costs[0][3] = connectcosts0[3];

 

// for each neighbor source is “me” must change in other files.
rtpacket.sourceid = 0;
rtpacket.mincost[0] = dt.costs[rtpacket.sourceid][0];
rtpacket.mincost[1] = dt.costs[rtpacket.sourceid][1];
rtpacket.mincost[2] = dt.costs[rtpacket.sourceid][2];
rtpacket.mincost[3] = dt.costs[rtpacket.sourceid][3];

for(int i = 0;i<4;i++)
if ((i!=rtpacket.sourceid)&&(dt.costs[rtpacket.sourceid][i]!=999))
{
rtpacket.destid = i;
tolayer2(rtpacket);
}
}
void rtupdate0(struct rtpkt *rcvdpkt)
{
struct rtpkt rtpacket;
// the node sending me information is “from” or v in the text on page 373
int v = rcvdpkt->sourceid;

// x is “me” the node that i am at. must change in other files.
int x = 0;

//
bool DV_Changed = false;

// update the location in my cost table
dt.costs[v][0] = rcvdpkt->mincost[0];
dt.costs[v][1] = rcvdpkt->mincost[1];
dt.costs[v][2] = rcvdpkt->mincost[2];
dt.costs[v][3] = rcvdpkt->mincost[3];

// The node that sent me information is v;
// page 373

// dt.costs os c on page 373 in the text
int c_v_x = dt.costs[x][v]; // this is part of line 14
for (int y = 0;y<4;y++)
{
if (y != x)
{
int D_x_y = dt.costs[x][y];
int D_v_y = dt.costs[v][y];
int new_D_x_y = c_v_x + D_v_y;
if (new_D_x_y < D_x_y)
{
dt.costs[x][y] = new_D_x_y;
DV_Changed = true;
}
}
}
if (DV_Changed)
{
// tell my neighbors
rtpacket.sourceid = x;
rtpacket.mincost[0] = dt.costs[rtpacket.sourceid][0];
rtpacket.mincost[1] = dt.costs[rtpacket.sourceid][1];
rtpacket.mincost[2] = dt.costs[rtpacket.sourceid][2];
rtpacket.mincost[3] = dt.costs[rtpacket.sourceid][3];

for(int i = 0;i<4;i++)
if ((i!=rtpacket.sourceid)&&(dt.costs[rtpacket.sourceid][i]!=999))
{
rtpacket.destid = i;
tolayer2(rtpacket);
}
}
}
void printdt0(struct distance_table *dtptr)

{
printf(” via \n”);
printf(” D0 | 1 2 3 \n”);
printf(” —-|—————–\n”);
printf(” 1| %3d %3d %3d\n”,dtptr->costs[1][1],
dtptr->costs[1][2],dtptr->costs[1][3]);
printf(“dest 2| %3d %3d %3d\n”,dtptr->costs[2][1],
dtptr->costs[2][2],dtptr->costs[2][3]);
printf(” 3| %3d %3d %3d\n”,dtptr->costs[3][1],
dtptr->costs[3][2],dtptr->costs[3][3]);
}

void linkhandler0(int linkid, int newcost)

/* called when cost from 0 to linkid changes from current value to newcost*/
/* You can leave this routine empty if you’re an undergrad. If you want */
/* to use this routine, you’ll need to change the value of the LINKCHANGE */
/* constant definition in prog3.c from 0 to 1 */

{
}