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#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <netinet/in.h>
#include <net/route.h>
#include "rip98d.h"
#define UNMATCH_ROUTE 0
#define NO_ROUTE 1
#define REPLACE_ROUTE 2
#define ADDITIONAL_ROUTE 3
static int cmp_route(struct route_struct *route, struct in_addr addr, int bits, int metric)
{
unsigned long int old_mask, new_mask;
unsigned long int old_addr, new_addr;
old_mask = ntohl(bits2mask(route->bits));
new_mask = ntohl(bits2mask(bits));
old_addr = route->addr.s_addr;
new_addr = addr.s_addr;
if (bits < route->bits) {
new_addr = ntohl(new_addr) & new_mask;
old_addr = ntohl(old_addr) & new_mask;
} else {
new_addr = ntohl(new_addr) & old_mask;
old_addr = ntohl(old_addr) & old_mask;
}
if (route->action == DEL_ROUTE || route->action == NEW_ROUTE)
return UNMATCH_ROUTE;
if (old_addr != new_addr)
return UNMATCH_ROUTE;
if (route->metric <= metric)
return NO_ROUTE;
if (debug && logging) {
syslog(LOG_DEBUG, "comparing old: %s/%d to\n", inet_ntoa(route->addr), route->bits);
syslog(LOG_DEBUG, " new: %s/%d\n", inet_ntoa(addr), bits);
}
if (route->bits <= bits) {
if (route->action == ORIG_ROUTE) {
if (debug && logging)
syslog(LOG_DEBUG, " better route, replacing existing route\n");
return REPLACE_ROUTE;
} else {
if (debug && logging)
syslog(LOG_DEBUG, " better route, adding additional route\n");
return ADDITIONAL_ROUTE;
}
} else {
if (debug && logging)
syslog(LOG_DEBUG, " better route, adding additional route\n");
return ADDITIONAL_ROUTE;
}
}
void receive_routes(int s)
{
unsigned char message[500], *p;
struct sockaddr_in rem_addr;
struct in_addr addr;
struct route_struct *route, *new;
struct sockaddr_in trg;
struct rtentry rt;
unsigned long int netmask;
unsigned long int network;
int bits, metric;
int found, matched;
socklen_t size;
int mess_len;
int i;
size = sizeof(struct sockaddr_in);
mess_len = recvfrom(s, message, 500, 0, (struct sockaddr *)&rem_addr, &size);
if (message[0] != RIPCMD_RESPONSE || message[1] != RIP_VERSION_98) {
if (debug && logging) {
syslog(LOG_DEBUG, "invalid RIP98 header received\n");
syslog(LOG_DEBUG, " cmd: %d vers: %d\n", message[0], message[1]);
}
return;
}
for (found = FALSE, i = 0; i < dest_count; i++) {
if (rem_addr.sin_addr.s_addr == dest_list[i].dest_addr.s_addr) {
found = TRUE;
break;
}
}
if (!found) {
if (debug && logging)
syslog(LOG_DEBUG, "RIP98 message from unknown address %s\n", inet_ntoa(rem_addr.sin_addr));
return;
}
if (debug && logging)
syslog(LOG_DEBUG, "RIP98 message received from %s\n", inet_ntoa(rem_addr.sin_addr));
for (p = message + RIP98_HEADER; p < message + mess_len; p += RIP98_ENTRY) {
memcpy((char *)&addr, (char *)p, sizeof(addr));
bits = p[4];
metric = p[5];
network = inet_netof(addr);
if (network == 0 || network == 127) {
if (debug && logging)
syslog(LOG_DEBUG, " route to %s/%d metric %d - rejected\n", inet_ntoa(addr), bits, metric);
continue;
}
if (restrict) {
if (network != 44) {
if (debug && logging)
syslog(LOG_DEBUG, " route to %s/%d metric %d - rejected\n", inet_ntoa(addr), bits, metric);
continue;
}
}
if (debug && logging)
syslog(LOG_DEBUG, " route to %s/%d metric %d\n", inet_ntoa(addr), bits, metric);
metric++;
if (metric > RIP98_INFINITY)
metric = RIP98_INFINITY;
found = FALSE;
matched = FALSE;
for (route = first_route; route != NULL; route = route->next) {
switch (cmp_route(route, addr, bits, metric)) {
case NO_ROUTE:
matched = TRUE;
break;
case REPLACE_ROUTE:
route->action = DEL_ROUTE;
case ADDITIONAL_ROUTE:
if (!found) {
if ((new = malloc(sizeof(struct route_struct))) == NULL) {
if (logging)
syslog(LOG_ERR, "out of memory\n");
return;
}
new->addr = addr;
new->bits = bits;
new->metric = metric;
new->action = NEW_ROUTE;
new->next = first_route;
first_route = new;
found = TRUE;
}
matched = TRUE;
break;
default:
break;
}
}
if (!matched) {
if ((new = malloc(sizeof(struct route_struct))) == NULL) {
if (logging)
syslog(LOG_ERR, "out of memory\n");
return;
}
new->addr = addr;
new->bits = bits;
new->metric = metric;
new->action = NEW_ROUTE;
new->next = first_route;
first_route = new;
}
}
for (route = first_route; route != NULL; route = route->next) {
if (route->action == DEL_ROUTE) {
memset((char *)&rt, 0, sizeof(rt));
trg.sin_family = AF_INET;
trg.sin_addr = route->addr;
trg.sin_port = 0;
memcpy((char *)&rt.rt_dst, (char *)&trg, sizeof(struct sockaddr));
if (ioctl(s, SIOCDELRT, &rt) < 0) {
if (logging)
syslog(LOG_ERR, "SIOCDELRT: %m");
}
}
}
for (route = first_route; route != NULL; route = route->next) {
if (route->action == NEW_ROUTE) {
memset((char *)&rt, 0, sizeof(rt));
trg.sin_family = AF_INET;
trg.sin_addr = route->addr;
trg.sin_port = 0;
memcpy((char *)&rt.rt_dst, (char *)&trg, sizeof(struct sockaddr));
rt.rt_flags = RTF_UP | RTF_GATEWAY | RTF_DYNAMIC;
if (route->bits == 32) {
rt.rt_flags |= RTF_HOST;
} else {
netmask = bits2mask(route->bits);
trg.sin_family = AF_INET;
memcpy((char *)&trg.sin_addr, (char *)&netmask, sizeof(struct in_addr));
trg.sin_port = 0;
memcpy((char *)&rt.rt_genmask, (char *)&trg, sizeof(struct sockaddr));
}
rt.rt_metric = route->metric + 1;
trg.sin_family = AF_INET;
trg.sin_addr = rem_addr.sin_addr;
trg.sin_port = 0;
memcpy((char *)&rt.rt_gateway, (char *)&trg, sizeof(struct sockaddr));
if (ioctl(s, SIOCADDRT, &rt) < 0) {
if (logging)
syslog(LOG_ERR, "SIOCADDRT: %m");
}
}
}
}
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