b539c8452f
code shrink while at it. function old new delta dhcp_option_strings - 258 +258 udhcp_run_script 1135 1174 +39 dhcp_option_lengths - 11 +11 udhcp_add_simple_option 93 92 -1 packet_num 4 - -4 read_opt 746 739 -7 udhcp_option_lengths 11 - -11 udhcpc_main 2590 2494 -96 dhcp_options 490 70 -420 ------------------------------------------------------------------------------ (add/remove: 2/2 grow/shrink: 1/4 up/down: 308/-539) Total: -231 bytes text data bss dec hex filename 775309 929 9100 785338 bfbba busybox_old 775098 929 9084 785111 bfad7 busybox_unstripped
150 lines
3.6 KiB
C
150 lines
3.6 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;
|
|
// TODO: use monotonic_sec()
|
|
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++)
|
|
continue;
|
|
|
|
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(leases[i]));
|
|
}
|
|
}
|
|
|
|
|
|
/* 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)
|
|
{
|
|
/* 16 zero bytes */
|
|
static const uint8_t blank_chaddr[16] = { 0 };
|
|
/* = { 0 } helps gcc to put it in rodata, not bss */
|
|
|
|
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;
|
|
}
|