1 /* vi: set sw=4 ts=4: */
3 * leases.c -- tools to manage DHCP leases
4 * Russ Dill <Russ.Dill@asu.edu> July 2001
9 #include <sys/socket.h>
10 #include <netinet/in.h>
11 #include <arpa/inet.h>
20 #include "static_leases.h"
23 uint8_t blank_chaddr[] = {[0 ... 15] = 0};
25 /* clear every lease out that chaddr OR yiaddr matches and is nonzero */
26 void clear_lease(uint8_t *chaddr, uint32_t yiaddr)
30 for (j = 0; j < 16 && !chaddr[j]; j++);
32 for (i = 0; i < server_config.max_leases; i++)
33 if ((j != 16 && !memcmp(leases[i].chaddr, chaddr, 16)) ||
34 (yiaddr && leases[i].yiaddr == yiaddr)) {
35 memset(&(leases[i]), 0, sizeof(struct dhcpOfferedAddr));
40 /* add a lease into the table, clearing out any old ones */
41 struct dhcpOfferedAddr *add_lease(uint8_t *chaddr, uint32_t yiaddr, unsigned long lease)
43 struct dhcpOfferedAddr *oldest;
45 /* clean out any old ones */
46 clear_lease(chaddr, yiaddr);
48 oldest = oldest_expired_lease();
51 memcpy(oldest->chaddr, chaddr, 16);
52 oldest->yiaddr = yiaddr;
53 oldest->expires = time(0) + lease;
60 /* true if a lease has expired */
61 int lease_expired(struct dhcpOfferedAddr *lease)
63 return (lease->expires < (unsigned long) time(0));
67 /* Find the oldest expired lease, NULL if there are no expired leases */
68 struct dhcpOfferedAddr *oldest_expired_lease(void)
70 struct dhcpOfferedAddr *oldest = NULL;
71 unsigned long oldest_lease = time(0);
75 for (i = 0; i < server_config.max_leases; i++)
76 if (oldest_lease > leases[i].expires) {
77 oldest_lease = leases[i].expires;
78 oldest = &(leases[i]);
85 /* Find the first lease that matches chaddr, NULL if no match */
86 struct dhcpOfferedAddr *find_lease_by_chaddr(uint8_t *chaddr)
90 for (i = 0; i < server_config.max_leases; i++)
91 if (!memcmp(leases[i].chaddr, chaddr, 16)) return &(leases[i]);
97 /* Find the first lease that matches yiaddr, NULL is no match */
98 struct dhcpOfferedAddr *find_lease_by_yiaddr(uint32_t yiaddr)
102 for (i = 0; i < server_config.max_leases; i++)
103 if (leases[i].yiaddr == yiaddr) return &(leases[i]);
109 /* check is an IP is taken, if it is, add it to the lease table */
110 static int check_ip(uint32_t addr)
114 if (arpping(addr, server_config.server, server_config.arp, server_config.interface) == 0) {
116 LOG(LOG_INFO, "%s belongs to someone, reserving it for %ld seconds",
117 inet_ntoa(temp), server_config.conflict_time);
118 add_lease(blank_chaddr, addr, server_config.conflict_time);
124 /* find an assignable address, it check_expired is true, we check all the expired leases as well.
125 * Maybe this should try expired leases by age... */
126 uint32_t find_address(int check_expired)
129 struct dhcpOfferedAddr *lease = NULL;
131 addr = ntohl(server_config.start); /* addr is in host order here */
132 for (;addr <= ntohl(server_config.end); addr++) {
134 /* ie, 192.168.55.0 */
135 if (!(addr & 0xFF)) continue;
137 /* ie, 192.168.55.255 */
138 if ((addr & 0xFF) == 0xFF) continue;
140 /* Only do if it isn't an assigned as a static lease */
141 if(!reservedIp(server_config.static_leases, htonl(addr)))
144 /* lease is not taken */
146 if ((!(lease = find_lease_by_yiaddr(ret)) ||
148 /* or it expired and we are checking for expired leases */
149 (check_expired && lease_expired(lease))) &&
151 /* and it isn't on the network */