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"
19 /* clear every lease out that chaddr OR yiaddr matches and is nonzero */
20 void clear_lease(u_int8_t *chaddr, u_int32_t yiaddr)
22 unsigned int i, blank_chaddr = 0, blank_yiaddr = 0;
24 for (i = 0; i < 16 && !chaddr[i]; i++);
25 if (i == 16) blank_chaddr = 1;
26 blank_yiaddr = (yiaddr == 0);
28 for (i = 0; i < server_config.max_leases; i++)
29 if ((!blank_chaddr && !memcmp(leases[i].chaddr, chaddr, 16)) ||
30 (!blank_yiaddr && leases[i].yiaddr == yiaddr)) {
31 memset(&(leases[i]), 0, sizeof(struct dhcpOfferedAddr));
36 /* add a lease into the table, clearing out any old ones */
37 struct dhcpOfferedAddr *add_lease(u_int8_t *chaddr, u_int32_t yiaddr, unsigned long lease)
39 struct dhcpOfferedAddr *oldest;
41 /* clean out any old ones */
42 clear_lease(chaddr, yiaddr);
44 oldest = oldest_expired_lease();
47 memcpy(oldest->chaddr, chaddr, 16);
48 oldest->yiaddr = yiaddr;
49 oldest->expires = time(0) + lease;
56 /* true if a lease has expired */
57 int lease_expired(struct dhcpOfferedAddr *lease)
59 return (lease->expires < (unsigned long) time(0));
63 /* Find the oldest expired lease, NULL if there are no expired leases */
64 struct dhcpOfferedAddr *oldest_expired_lease(void)
66 struct dhcpOfferedAddr *oldest = NULL;
67 unsigned long oldest_lease = time(0);
71 for (i = 0; i < server_config.max_leases; i++)
72 if (oldest_lease > leases[i].expires) {
73 oldest_lease = leases[i].expires;
74 oldest = &(leases[i]);
81 /* Find the first lease that matches chaddr, NULL if no match */
82 struct dhcpOfferedAddr *find_lease_by_chaddr(u_int8_t *chaddr)
86 for (i = 0; i < server_config.max_leases; i++)
87 if (!memcmp(leases[i].chaddr, chaddr, 16)) return &(leases[i]);
93 /* Find the first lease that matches yiaddr, NULL is no match */
94 struct dhcpOfferedAddr *find_lease_by_yiaddr(u_int32_t yiaddr)
98 for (i = 0; i < server_config.max_leases; i++)
99 if (leases[i].yiaddr == yiaddr) return &(leases[i]);
105 /* find an assignable address, it check_expired is true, we check all the expired leases as well.
106 * Maybe this should try expired leases by age... */
107 u_int32_t find_address(int check_expired)
109 u_int32_t addr, ret = 0;
110 struct dhcpOfferedAddr *lease = NULL;
112 addr = server_config.start;
114 for (;ntohl(addr) <= ntohl(server_config.end) ;addr = htonl(ntohl(addr) + 1)) {
116 /* ie, 192.168.55.0 */
117 if (!(ntohl(addr) & 0xFF)) continue;
119 /* ie, 192.168.55.255 */
120 if ((ntohl(addr) & 0xFF) == 0xFF) continue;
122 /* the ip is not in the pclist table */
124 if(Ip_in_pclist(inet_ntoa(temp)))continue;
126 /* lease is not taken */
127 if ((!(lease = find_lease_by_yiaddr(addr)) ||
129 /* or it expired and we are checking for expired leases */
130 (check_expired && lease_expired(lease))) &&
132 /* and it isn't on the network */
142 /* check is an IP is taken, if it is, add it to the lease table */
143 int check_ip(u_int32_t addr)
145 char blank_chaddr[] = {[0 ... 15] = 0};
148 if (!arpping(addr, server_config.server, server_config.arp, server_config.interface)) {
150 LOG(LOG_INFO, "%s belongs to someone, reserving it for %ld seconds",
151 inet_ntoa(temp), server_config.conflict_time);
152 add_lease(blank_chaddr, addr, server_config.conflict_time);