42b3dea9bf
* arpping(): smaller and even probably fixed * lots of variables/params converted: ulong -> uint32_t * uptime() nuked in favor of monotonic_sec() * udhcp_get_packet(): only one "bad vendor", simplify function old new delta reservedIp 36 35 -1 udhcpc_main 2462 2460 -2 addStaticLease 64 62 -2 static.broken_vendors 16 - -16 uptime 19 - -19 udhcpd_main 1273 1238 -35 udhcp_get_packet 223 184 -39 .rodata 144162 144106 -56 arpping 690 609 -81 ------------------------------------------------------------------------------ (add/remove: 0/2 grow/shrink: 0/7 up/down: 0/-251) Total: -251 bytes text data bss dec hex filename 734241 3028 14400 751669 b7835 busybox_old 734005 3028 14400 751433 b7749 busybox_unstripped
149 lines
3.5 KiB
C
149 lines
3.5 KiB
C
/* vi: set sw=4 ts=4: */
|
|
/*
|
|
* leases.c -- tools to manage DHCP leases
|
|
* Russ Dill <Russ.Dill@asu.edu> July 2001
|
|
*/
|
|
|
|
#include "common.h"
|
|
#include "dhcpd.h"
|
|
|
|
|
|
/* Find the oldest expired lease, NULL if there are no expired leases */
|
|
static struct dhcpOfferedAddr *oldest_expired_lease(void)
|
|
{
|
|
struct dhcpOfferedAddr *oldest = NULL;
|
|
unsigned long oldest_lease = time(0);
|
|
unsigned 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;
|
|
}
|
|
|
|
|
|
/* clear every lease out that chaddr OR yiaddr matches and is nonzero */
|
|
static void clear_lease(const uint8_t *chaddr, uint32_t yiaddr)
|
|
{
|
|
unsigned 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) != 0)
|
|
|| (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(const uint8_t *chaddr, uint32_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 first lease that matches chaddr, NULL if no match */
|
|
struct dhcpOfferedAddr *find_lease_by_chaddr(const uint8_t *chaddr)
|
|
{
|
|
unsigned 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(uint32_t yiaddr)
|
|
{
|
|
unsigned 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 nobody_responds_to_arp(uint32_t addr)
|
|
{
|
|
static const uint8_t blank_chaddr[16]; /* 16 zero bytes */
|
|
|
|
struct in_addr temp;
|
|
int r;
|
|
|
|
r = arpping(addr, server_config.server, server_config.arp, server_config.interface);
|
|
if (r)
|
|
return r;
|
|
|
|
temp.s_addr = addr;
|
|
bb_info_msg("%s belongs to someone, reserving it for %u seconds",
|
|
inet_ntoa(temp), (unsigned)server_config.conflict_time);
|
|
add_lease(blank_chaddr, addr, server_config.conflict_time);
|
|
return 0;
|
|
}
|
|
|
|
|
|
/* find an assignable address, if check_expired is true, we check all the expired leases as well.
|
|
* Maybe this should try expired leases by age... */
|
|
uint32_t find_address(int check_expired)
|
|
{
|
|
uint32_t addr, ret;
|
|
struct dhcpOfferedAddr *lease = NULL;
|
|
|
|
addr = server_config.start_ip; /* addr is in host order here */
|
|
for (;addr <= server_config.end_ip; addr++) {
|
|
|
|
/* ie, 192.168.55.0 */
|
|
if (!(addr & 0xFF)) continue;
|
|
|
|
/* ie, 192.168.55.255 */
|
|
if ((addr & 0xFF) == 0xFF) continue;
|
|
|
|
/* Only do if it isn't assigned as a static lease */
|
|
ret = htonl(addr);
|
|
if (!reservedIp(server_config.static_leases, ret)) {
|
|
/* lease is not taken */
|
|
lease = find_lease_by_yiaddr(ret);
|
|
|
|
/* no lease or it expired and we are checking for expired leases */
|
|
if ((!lease || (check_expired && lease_expired(lease)))
|
|
&& nobody_responds_to_arp(ret) /* it isn't used on the network */
|
|
) {
|
|
return ret;
|
|
}
|
|
}
|
|
}
|
|
return 0;
|
|
}
|