1 /* vi: set sw=4 ts=4: */
3 * leases.c -- tools to manage DHCP leases
4 * Russ Dill <Russ.Dill@asu.edu> July 2001
6 * Licensed under GPLv2, see file LICENSE in this tarball for details.
13 /* Find the oldest expired lease, NULL if there are no expired leases */
14 static struct dyn_lease *oldest_expired_lease(void)
16 struct dyn_lease *oldest_lease = NULL;
17 leasetime_t oldest_time = time(NULL);
20 /* Unexpired leases have g_leases[i].expires >= current time
21 * and therefore can't ever match */
22 for (i = 0; i < server_config.max_leases; i++) {
23 if (g_leases[i].expires < oldest_time) {
24 oldest_time = g_leases[i].expires;
25 oldest_lease = &g_leases[i];
32 /* Clear out all leases with matching nonzero chaddr OR yiaddr.
33 * If chaddr == NULL, this is a conflict lease.
35 static void clear_leases(const uint8_t *chaddr, uint32_t yiaddr)
39 for (i = 0; i < server_config.max_leases; i++) {
40 if ((chaddr && memcmp(g_leases[i].lease_mac, chaddr, 6) == 0)
41 || (yiaddr && g_leases[i].lease_nip == yiaddr)
43 memset(&g_leases[i], 0, sizeof(g_leases[i]));
49 /* Add a lease into the table, clearing out any old ones
50 * If chaddr == NULL, this is a conflict lease.
52 struct dyn_lease* FAST_FUNC add_lease(
53 const uint8_t *chaddr, uint32_t yiaddr,
54 leasetime_t leasetime,
55 const char *hostname, int hostname_len)
57 struct dyn_lease *oldest;
59 /* clean out any old ones */
60 clear_leases(chaddr, yiaddr);
62 oldest = oldest_expired_lease();
65 memset(oldest, 0, sizeof(*oldest));
68 if (hostname_len > sizeof(oldest->hostname))
69 hostname_len = sizeof(oldest->hostname);
70 p = safe_strncpy(oldest->hostname, hostname, hostname_len);
71 /* sanitization (s/non-ASCII/^/g) */
73 if (*p < ' ' || *p > 126)
79 memcpy(oldest->lease_mac, chaddr, 6);
80 oldest->lease_nip = yiaddr;
81 oldest->expires = time(NULL) + leasetime;
88 /* True if a lease has expired */
89 int FAST_FUNC is_expired_lease(struct dyn_lease *lease)
91 return (lease->expires < (leasetime_t) time(NULL));
95 /* Find the first lease that matches MAC, NULL if no match */
96 struct dyn_lease* FAST_FUNC find_lease_by_mac(const uint8_t *mac)
100 for (i = 0; i < server_config.max_leases; i++)
101 if (memcmp(g_leases[i].lease_mac, mac, 6) == 0)
108 /* Find the first lease that matches IP, NULL is no match */
109 struct dyn_lease* FAST_FUNC find_lease_by_nip(uint32_t nip)
113 for (i = 0; i < server_config.max_leases; i++)
114 if (g_leases[i].lease_nip == nip)
121 /* Check if the IP is taken; if it is, add it to the lease table */
122 static int nobody_responds_to_arp(uint32_t nip, const uint8_t *safe_mac)
127 r = arpping(nip, safe_mac,
128 server_config.server_nip,
129 server_config.server_mac,
130 server_config.interface);
135 bb_info_msg("%s belongs to someone, reserving it for %u seconds",
136 inet_ntoa(temp), (unsigned)server_config.conflict_time);
137 add_lease(NULL, nip, server_config.conflict_time, NULL, 0);
142 /* Find a new usable (we think) address */
143 uint32_t FAST_FUNC find_free_or_expired_nip(const uint8_t *safe_mac)
146 struct dyn_lease *oldest_lease = NULL;
148 addr = server_config.start_ip; /* addr is in host order here */
149 for (; addr <= server_config.end_ip; addr++) {
151 struct dyn_lease *lease;
153 /* ie, 192.168.55.0 */
154 if ((addr & 0xff) == 0)
156 /* ie, 192.168.55.255 */
157 if ((addr & 0xff) == 0xff)
160 /* is this a static lease addr? */
161 if (is_nip_reserved(server_config.static_leases, nip))
164 lease = find_lease_by_nip(nip);
166 if (nobody_responds_to_arp(nip, safe_mac))
169 if (!oldest_lease || lease->expires < oldest_lease->expires)
170 oldest_lease = lease;
175 && is_expired_lease(oldest_lease)
176 && nobody_responds_to_arp(oldest_lease->lease_nip, safe_mac)
178 return oldest_lease->lease_nip;