mirror of
https://github.com/sheumann/hush.git
synced 2024-12-23 05:29:58 +00:00
152 lines
3.5 KiB
C
152 lines
3.5 KiB
C
/*
|
|
* leases.c -- tools to manage DHCP leases
|
|
* Russ Dill <Russ.Dill@asu.edu> July 2001
|
|
*/
|
|
|
|
#include <time.h>
|
|
#include <string.h>
|
|
#include <sys/socket.h>
|
|
#include <netinet/in.h>
|
|
#include <arpa/inet.h>
|
|
|
|
#include "dhcpd.h"
|
|
#include "files.h"
|
|
#include "options.h"
|
|
#include "leases.h"
|
|
#include "arpping.h"
|
|
#include "common.h"
|
|
|
|
|
|
unsigned char blank_chaddr[] = {[0 ... 15] = 0};
|
|
|
|
/* clear every lease out that chaddr OR yiaddr matches and is nonzero */
|
|
void clear_lease(u_int8_t *chaddr, u_int32_t yiaddr)
|
|
{
|
|
unsigned int i, j;
|
|
|
|
for (j = 0; j < 16 && !chaddr[j]; j++);
|
|
|
|
for (i = 0; i < server_config.max_leases; i++)
|
|
if ((j != 16 && !memcmp(leases[i].chaddr, chaddr, 16)) ||
|
|
(yiaddr && leases[i].yiaddr == yiaddr)) {
|
|
memset(&(leases[i]), 0, sizeof(struct dhcpOfferedAddr));
|
|
}
|
|
}
|
|
|
|
|
|
/* add a lease into the table, clearing out any old ones */
|
|
struct dhcpOfferedAddr *add_lease(u_int8_t *chaddr, u_int32_t yiaddr, unsigned long lease)
|
|
{
|
|
struct dhcpOfferedAddr *oldest;
|
|
|
|
/* clean out any old ones */
|
|
clear_lease(chaddr, yiaddr);
|
|
|
|
oldest = oldest_expired_lease();
|
|
|
|
if (oldest) {
|
|
memcpy(oldest->chaddr, chaddr, 16);
|
|
oldest->yiaddr = yiaddr;
|
|
oldest->expires = time(0) + lease;
|
|
}
|
|
|
|
return oldest;
|
|
}
|
|
|
|
|
|
/* true if a lease has expired */
|
|
int lease_expired(struct dhcpOfferedAddr *lease)
|
|
{
|
|
return (lease->expires < (unsigned long) time(0));
|
|
}
|
|
|
|
|
|
/* Find the oldest expired lease, NULL if there are no expired leases */
|
|
struct dhcpOfferedAddr *oldest_expired_lease(void)
|
|
{
|
|
struct dhcpOfferedAddr *oldest = NULL;
|
|
unsigned long oldest_lease = time(0);
|
|
unsigned int i;
|
|
|
|
|
|
for (i = 0; i < server_config.max_leases; i++)
|
|
if (oldest_lease > leases[i].expires) {
|
|
oldest_lease = leases[i].expires;
|
|
oldest = &(leases[i]);
|
|
}
|
|
return oldest;
|
|
|
|
}
|
|
|
|
|
|
/* Find the first lease that matches chaddr, NULL if no match */
|
|
struct dhcpOfferedAddr *find_lease_by_chaddr(u_int8_t *chaddr)
|
|
{
|
|
unsigned int i;
|
|
|
|
for (i = 0; i < server_config.max_leases; i++)
|
|
if (!memcmp(leases[i].chaddr, chaddr, 16)) return &(leases[i]);
|
|
|
|
return NULL;
|
|
}
|
|
|
|
|
|
/* Find the first lease that matches yiaddr, NULL is no match */
|
|
struct dhcpOfferedAddr *find_lease_by_yiaddr(u_int32_t yiaddr)
|
|
{
|
|
unsigned int i;
|
|
|
|
for (i = 0; i < server_config.max_leases; i++)
|
|
if (leases[i].yiaddr == yiaddr) return &(leases[i]);
|
|
|
|
return NULL;
|
|
}
|
|
|
|
|
|
/* check is an IP is taken, if it is, add it to the lease table */
|
|
static int check_ip(u_int32_t addr)
|
|
{
|
|
struct in_addr temp;
|
|
|
|
if (arpping(addr, server_config.server, server_config.arp, server_config.interface) == 0) {
|
|
temp.s_addr = addr;
|
|
LOG(LOG_INFO, "%s belongs to someone, reserving it for %ld seconds",
|
|
inet_ntoa(temp), server_config.conflict_time);
|
|
add_lease(blank_chaddr, addr, server_config.conflict_time);
|
|
return 1;
|
|
} else return 0;
|
|
}
|
|
|
|
|
|
/* find an assignable address, it check_expired is true, we check all the expired leases as well.
|
|
* Maybe this should try expired leases by age... */
|
|
u_int32_t find_address(int check_expired)
|
|
{
|
|
u_int32_t addr, ret;
|
|
struct dhcpOfferedAddr *lease = NULL;
|
|
|
|
addr = ntohl(server_config.start); /* addr is in host order here */
|
|
for (;addr <= ntohl(server_config.end); addr++) {
|
|
|
|
/* ie, 192.168.55.0 */
|
|
if (!(addr & 0xFF)) continue;
|
|
|
|
/* ie, 192.168.55.255 */
|
|
if ((addr & 0xFF) == 0xFF) continue;
|
|
|
|
/* lease is not taken */
|
|
ret = htonl(addr);
|
|
if ((!(lease = find_lease_by_yiaddr(ret)) ||
|
|
|
|
/* or it expired and we are checking for expired leases */
|
|
(check_expired && lease_expired(lease))) &&
|
|
|
|
/* and it isn't on the network */
|
|
!check_ip(ret)) {
|
|
return ret;
|
|
break;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|