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routing_table.c
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routing_table.c
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#include "unp.h"
#include "hw_addrs.h"
#include <linux/if_packet.h>
#include <linux/if_ether.h>
#include <linux/if_arp.h>
#include <time.h>
struct routing_table
{
unsigned char destination_ipaddress[10][INET_ADDRSTRLEN];
unsigned char next_hop[10][ETH_ALEN];
int hop_number[10];
time_t stale_time[10];
};
int isExistDest(struct routing_table rt, unsigned char *dest_ipaddr){
int i;
for(i = 0; i < 10; i++){
if(!strcmp(dest_ipaddr, rt.destination_ipaddress[i])){
return 1;
}
}
return 0;
}
/*use when a client at a node calls msg_send, and if an entry
for the destination node already exists in the routing table
*/
int checkStaleEntry(struct routing_table *rt, unsigned char *dest_ipaddr, int t_sec){
int i, index, isStaleEntry;
time_t current = time(NULL);
isStaleEntry = 0;
for(i = 0; i < 10; i++){
if(!strcmp(dest_ipaddr, rt -> destination_ipaddress[i])){
index = i;
if(current > (rt -> stale_time[i] + t_sec)){
isStaleEntry = 1;
break;
}
}
}
//delete this stale entry(copy the next entry forward)
for(i = index; i < 9; i++){
memcpy(rt -> destination_ipaddress[i], rt -> destination_ipaddress[i+1], INET_ADDRSTRLEN);
memcpy(rt -> next_hop[i], rt -> next_hop[i+1], ETH_ALEN);
rt -> hop_number[i] = rt -> hop_number[i+1];
rt -> stale_time[i] = rt -> stale_time[i+1];
}
//zero the last entry
bzero(rt -> destination_ipaddress[9], INET_ADDRSTRLEN);
bzero(rt -> next_hop[9], ETH_ALEN);
rt -> hop_number[9] = 0;
rt -> stale_time[9] = 0;
if(isStaleEntry){
return 1; // has been stale
}
return 0;
}
void getNextHop(struct routing_table rt, unsigned char* dest_ipaddr, unsigned char* dest_mac){
int i;
for(i = 0; i < 10; i++){
if(!strcmp(dest_ipaddr, rt.destination_ipaddress[i])){
break;
}
}
memcpy(dest_mac, rt.next_hop[i], ETH_ALEN);
}
//use when new odr message(including rrep) receive
void updateNewDest(struct routing_table *rt, unsigned char *dest_ipaddr, unsigned char *next_h, int h_num){
int i, index, isExistDest;
//two senario: the destination exists or not exists
isExistDest = 0;
for(i = 0; i < 10; i++){
if(rt -> destination_ipaddress[i][0] == '\0'){
break;
}
if(!strcmp(dest_ipaddr, rt -> destination_ipaddress[i])){
index = i;
isExistDest = 1;
}
}
if(isExistDest){
if(h_num < rt -> hop_number[index]){
memcpy(rt -> next_hop[index], next_h, ETH_ALEN);
rt -> hop_number[index] = h_num;
rt -> stale_time[index] = time(NULL);
}
}else{
memcpy(rt -> destination_ipaddress[i], dest_ipaddr, INET_ADDRSTRLEN);
memcpy(rt -> next_hop[i], next_h, ETH_ALEN);
rt -> hop_number[i] = h_num;
rt -> stale_time[i] = time(NULL);
}
}