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distance_vector.c
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distance_vector.c
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#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include"distance_vector.h"
node *nodelist;
int total_nodes;
FILE *file;
queue node_queue;
void init_queue()
{
int i;
node_queue.index = 0;
node_queue.id_list = (queue_node*)malloc(sizeof(queue_node)*1000000);
for(i=0;i<total_nodes;i++)
node_queue.id_list[i].node_id=-1;
}
void add_to_queue(int id,int neighbor)
{
node_queue.id_list[node_queue.index].node_id = id;
node_queue.id_list[node_queue.index].neighbor_id = neighbor;
node_queue.index++;
}
queue_node remove_from_queue()
{
int i;
queue_node ret = node_queue.id_list[0];
//printf("Index is %d\n",node_queue.index);
if(node_queue.index>=0)
{
for(i=1;i<node_queue.index;i++)
node_queue.id_list[i-1] = node_queue.id_list[i];
node_queue.id_list[node_queue.index].node_id=-1;
node_queue.index--;
}
return ret;
}
void initialize_topology()
{
int i,j;
fseek(file,0,SEEK_SET);
fscanf(file,"%d\n",&total_nodes);
// printf("Total nodes %d\n",total_nodes);
nodelist = (node *)malloc(sizeof(node)*total_nodes);
for(i = 0;i< total_nodes;i++)
{ //initialize nodelist structure
nodelist[i].id = i;
nodelist[i].send_flag = 1;
nodelist[i].no_of_neighbors = 0;
nodelist[i].count = 0;
nodelist[i].dv = (double*) malloc(sizeof(double)*total_nodes);
nodelist[i].next_hop = (int*) malloc(sizeof(int)*total_nodes);
for(j=0;j<total_nodes;j++)
{
if(i==j)
{
nodelist[i].dv[j] = 0;
nodelist[i].next_hop[j] = i;
}
else
{
nodelist[i].dv[j] = INF;
nodelist[i].next_hop[j] = -1;
}
}
nodelist[i].neighbor_list = (neighbor*)malloc(sizeof(neighbor)*total_nodes);
memset(nodelist[i].neighbor_list,0,sizeof(neighbor)*total_nodes);
}
// printf("out of inital setup.. reading file now\n");
//memset(path,-1,total_nodes*sizeof(int)); //reset path array
int temp_i = -1,temp_j = -1;
double temp_cost = 0.0f;
while(fscanf(file,"%d %d %lf",&temp_i,&temp_j,&temp_cost)!= EOF){
nodelist[temp_i-1].neighbor_list[nodelist[temp_i-1].no_of_neighbors].id = temp_j-1;
nodelist[temp_j-1].neighbor_list[nodelist[temp_j-1].no_of_neighbors].id = temp_i-1;
nodelist[temp_i-1].neighbor_list[nodelist[temp_i-1].no_of_neighbors].index_in_neighbor = nodelist[temp_j-1].no_of_neighbors;
nodelist[temp_j-1].neighbor_list[nodelist[temp_j-1].no_of_neighbors].index_in_neighbor = nodelist[temp_i-1].no_of_neighbors;
nodelist[temp_i-1].neighbor_list[nodelist[temp_i-1].no_of_neighbors].dv = (double*)malloc(sizeof(double)*total_nodes);
for(i=0;i<total_nodes;i++)
nodelist[temp_i-1].neighbor_list[nodelist[temp_i-1].no_of_neighbors].dv[i] = INF;
nodelist[temp_j-1].neighbor_list[nodelist[temp_j-1].no_of_neighbors].dv = (double*)malloc(sizeof(double)*total_nodes);
for(i=0;i<total_nodes;i++)
nodelist[temp_j-1].neighbor_list[nodelist[temp_j-1].no_of_neighbors].dv[i] = INF;
nodelist[temp_i-1].no_of_neighbors++;
nodelist[temp_j-1].no_of_neighbors++;
nodelist[temp_i-1].dv[temp_j-1] = temp_cost;
nodelist[temp_i-1].next_hop[temp_j-1] = temp_j-1;
nodelist[temp_j-1].dv[temp_i-1] = temp_cost;
nodelist[temp_j-1].next_hop[temp_i-1] = temp_i-1;
}
}
void print_topology()
{
int i,j;
for(i=0;i<total_nodes;i++)
{
printf("\nNode %d ",nodelist[i].id+1);
printf("Neighbours %d\n",nodelist[i].no_of_neighbors);
printf("Count is: %d\n",nodelist[i].count);
// printf("Neighbors are\n");
for(j=0;j<nodelist[i].no_of_neighbors;j++)
// printf("%2d\t",nodelist[i].neighbor_list[j].id+1);
printf("\n");
for(j=0;j<nodelist[i].no_of_neighbors;j++)
printf("%2d\t",nodelist[i].neighbor_list[j].index_in_neighbor);
printf("\n");
printf("\nDistance vector is\n");
for(j=0;j<total_nodes;j++)
printf("%.2lf\t",nodelist[i].dv[j]);
//printf("\n");
}
}
void send_distance_vector(int node_id)
{
int i,j;
for(i=0;i<nodelist[node_id].no_of_neighbors;i++)
{
int curr_neighbor = nodelist[node_id].neighbor_list[i].id;
int curr_index = nodelist[node_id].neighbor_list[i].index_in_neighbor;
for(j=0;j<total_nodes;j++)
nodelist[curr_neighbor].neighbor_list[curr_index].dv[j] = nodelist[node_id].dv[j];
add_to_queue(curr_neighbor,curr_index);
}
}
void update_distance_vector(int node_id,int neighbor_index)
{
int i;
int flag = 0;
int neighbor_id = nodelist[node_id].neighbor_list[neighbor_index].id;
//printf("node is %d and neighbor is %d\n",node_id,neighbor_id);
for(i=0;i<total_nodes;i++)
{
double new_distance = nodelist[node_id].dv[neighbor_id]+nodelist[node_id].neighbor_list[neighbor_index].dv[i];
// printf("for node %d current distance is %.2lf and new distance is %.2lf\n",i,nodelist[node_id].dv[i],new_distance);
if(nodelist[node_id].dv[i]>new_distance)
{
nodelist[node_id].next_hop[i] = neighbor_id;
nodelist[node_id].dv[i] = new_distance;
nodelist[node_id].send_flag++;
flag++;
}
}
if(flag)
{
nodelist[node_id].count++;
//printf("send flag is %d\n",nodelist[node_id].send_flag);
}
}
void print_r_table(int i)
{
int j;
printf("Destination\tNext Hop\tCost\n");
printf("------------------------------------\n");
for(j=0;j<total_nodes;j++)
printf(" %d\t\t %d\t\t%.2lf\n",j+1,nodelist[i].next_hop[j]+1,nodelist[i].dv[j]);
}
int get_max_count()
{
int i;
int max_count_id = 0;
for(i=1;i<total_nodes;i++)
if(nodelist[max_count_id].count<nodelist[i].count)
max_count_id = i;
return max_count_id;
}
int main(int argc, char *argv[]){
int initial_node;
queue_node curr_node;
total_nodes = -1;
if(argc != 5){
perror("Incorrect command line arguments\n");
exit(-1);
}
file = fopen(argv[2],"r");
if(!file){
perror("Cannot Open File\n");
exit(-1);
}
initialize_topology();
init_queue();
//print_topology();
initial_node = atoi(argv[1])-1;
send_distance_vector(initial_node);
while(1)
{
curr_node = remove_from_queue();
// printf("inside while %d\n",curr_node.node_id);
if(curr_node.node_id == -1)
break;
update_distance_vector(curr_node.node_id,curr_node.neighbor_id);
if(nodelist[curr_node.node_id].send_flag)
send_distance_vector(curr_node.node_id);
nodelist[curr_node.node_id].send_flag = 0;
}
//print_topology();
int node1 = atoi(argv[3])-1;
int node2 = atoi(argv[4])-1;
printf("\n\nRouting table for node %d-->\n\n",node1+1);
print_r_table(node1);
printf("\nRouting Table for node %d-->\n\n",node2+1);
print_r_table(node2);
int max_count_id = get_max_count();
printf("\nCost of the Least cost path between Node1(%d) and Node 2(%d) is : %.2lf\n\n",node1+1,node2+1,nodelist[node1].dv[node2]);
// printf("\nMax iterations is %d for node %d \n",nodelist[max_count_id].count,max_count_id+1);
return 0;
}