2 * leases.c -- tools to manage DHCP leases
3 * Russ Dill <Russ.Dill@asu.edu> July 2001
8 #include <sys/socket.h>
9 #include <netinet/in.h>
10 #include <arpa/inet.h>
18 #include "pclisttab.h"
21 /* clear every lease out that chaddr OR yiaddr matches and is nonzero */
22 void clear_lease(u_int8_t *chaddr, u_int32_t yiaddr)
24 unsigned int i, blank_chaddr = 0, blank_yiaddr = 0;
26 for (i = 0; i < 16 && !chaddr[i]; i++);
27 if (i == 16) blank_chaddr = 1;
28 blank_yiaddr = (yiaddr == 0);
30 for (i = 0; i < server_config.max_leases; i++)
31 if ((!blank_chaddr && !memcmp(leases[i].chaddr, chaddr, 16)) ||
32 (!blank_yiaddr && leases[i].yiaddr == yiaddr)) {
33 memset(&(leases[i]), 0, sizeof(struct dhcpOfferedAddr));
38 /* add a lease into the table, clearing out any old ones */
39 struct dhcpOfferedAddr *add_lease(u_int8_t *chaddr, u_int32_t yiaddr, unsigned long lease)
41 struct dhcpOfferedAddr *oldest;
43 /* clean out any old ones */
44 clear_lease(chaddr, yiaddr);
46 oldest = oldest_expired_lease();
49 memcpy(oldest->chaddr, chaddr, 16);
50 oldest->yiaddr = yiaddr;
51 oldest->expires = time(0) + lease;
58 /* true if a lease has expired */
59 int lease_expired(struct dhcpOfferedAddr *lease)
61 return (lease->expires < (unsigned long) time(0));
65 /* Find the oldest expired lease, NULL if there are no expired leases */
66 struct dhcpOfferedAddr *oldest_expired_lease(void)
68 struct dhcpOfferedAddr *oldest = NULL;
69 unsigned long oldest_lease = time(0);
73 for (i = 0; i < server_config.max_leases; i++)
74 if (oldest_lease > leases[i].expires) {
75 oldest_lease = leases[i].expires;
76 oldest = &(leases[i]);
83 /* Find the first lease that matches chaddr, NULL if no match */
84 struct dhcpOfferedAddr *find_lease_by_chaddr(u_int8_t *chaddr)
88 for (i = 0; i < server_config.max_leases; i++)
89 if (!memcmp(leases[i].chaddr, chaddr, 16)) return &(leases[i]);
95 /* Find the first lease that matches yiaddr, NULL is no match */
96 struct dhcpOfferedAddr *find_lease_by_yiaddr(u_int32_t yiaddr)
100 for (i = 0; i < server_config.max_leases; i++)
101 if (leases[i].yiaddr == yiaddr) return &(leases[i]);
107 /* find an assignable address, it check_expired is true, we check all the expired leases as well.
108 * Maybe this should try expired leases by age... */
109 u_int32_t find_address(int check_expired)
111 u_int32_t addr, ret = 0;
112 struct dhcpOfferedAddr *lease = NULL;
115 addr = server_config.start;
117 for (;ntohl(addr) <= ntohl(server_config.end) ;addr = htonl(ntohl(addr) + 1)) {
119 /* ie, 192.168.55.0 */
120 if (!(ntohl(addr) & 0xFF)) continue;
122 /* ie, 192.168.55.255 */
123 if ((ntohl(addr) & 0xFF) == 0xFF) continue;
125 /* the ip is not in the pclist table */
127 if(Ip_in_pclist(inet_ntoa(temp)))continue;
129 /* lease is not taken */
130 if ((!(lease = find_lease_by_yiaddr(addr)) ||
132 /* or it expired and we are checking for expired leases */
133 (check_expired && lease_expired(lease))) &&
135 /* and it isn't on the network */
145 /* check is an IP is taken, if it is, add it to the lease table */
146 int check_ip(u_int32_t addr)
148 char blank_chaddr[] = {[0 ... 15] = 0};
151 if (!arpping(addr, server_config.server, server_config.arp, server_config.interface)) {
153 LOG(LOG_INFO, "%s belongs to someone, reserving it for %ld seconds",
154 inet_ntoa(temp), server_config.conflict_time);
155 add_lease(blank_chaddr, addr, server_config.conflict_time);