diff options
Diffstat (limited to 'networking/udhcp/leases.c')
-rw-r--r-- | networking/udhcp/leases.c | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/networking/udhcp/leases.c b/networking/udhcp/leases.c new file mode 100644 index 000000000..7ade91d93 --- /dev/null +++ b/networking/udhcp/leases.c | |||
@@ -0,0 +1,151 @@ | |||
1 | /* | ||
2 | * leases.c -- tools to manage DHCP leases | ||
3 | * Russ Dill <Russ.Dill@asu.edu> July 2001 | ||
4 | */ | ||
5 | |||
6 | #include <time.h> | ||
7 | #include <string.h> | ||
8 | #include <sys/socket.h> | ||
9 | #include <netinet/in.h> | ||
10 | #include <arpa/inet.h> | ||
11 | |||
12 | #include "debug.h" | ||
13 | #include "dhcpd.h" | ||
14 | #include "files.h" | ||
15 | #include "options.h" | ||
16 | #include "leases.h" | ||
17 | #include "arpping.h" | ||
18 | |||
19 | unsigned char blank_chaddr[] = {[0 ... 15] = 0}; | ||
20 | |||
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) | ||
23 | { | ||
24 | unsigned int i, j; | ||
25 | |||
26 | for (j = 0; j < 16 && !chaddr[j]; j++); | ||
27 | |||
28 | for (i = 0; i < server_config.max_leases; i++) | ||
29 | if ((j != 16 && !memcmp(leases[i].chaddr, chaddr, 16)) || | ||
30 | (yiaddr && leases[i].yiaddr == yiaddr)) { | ||
31 | memset(&(leases[i]), 0, sizeof(struct dhcpOfferedAddr)); | ||
32 | } | ||
33 | } | ||
34 | |||
35 | |||
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) | ||
38 | { | ||
39 | struct dhcpOfferedAddr *oldest; | ||
40 | |||
41 | /* clean out any old ones */ | ||
42 | clear_lease(chaddr, yiaddr); | ||
43 | |||
44 | oldest = oldest_expired_lease(); | ||
45 | |||
46 | if (oldest) { | ||
47 | memcpy(oldest->chaddr, chaddr, 16); | ||
48 | oldest->yiaddr = yiaddr; | ||
49 | oldest->expires = time(0) + lease; | ||
50 | } | ||
51 | |||
52 | return oldest; | ||
53 | } | ||
54 | |||
55 | |||
56 | /* true if a lease has expired */ | ||
57 | int lease_expired(struct dhcpOfferedAddr *lease) | ||
58 | { | ||
59 | return (lease->expires < (unsigned long) time(0)); | ||
60 | } | ||
61 | |||
62 | |||
63 | /* Find the oldest expired lease, NULL if there are no expired leases */ | ||
64 | struct dhcpOfferedAddr *oldest_expired_lease(void) | ||
65 | { | ||
66 | struct dhcpOfferedAddr *oldest = NULL; | ||
67 | unsigned long oldest_lease = time(0); | ||
68 | unsigned int i; | ||
69 | |||
70 | |||
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]); | ||
75 | } | ||
76 | return oldest; | ||
77 | |||
78 | } | ||
79 | |||
80 | |||
81 | /* Find the first lease that matches chaddr, NULL if no match */ | ||
82 | struct dhcpOfferedAddr *find_lease_by_chaddr(u_int8_t *chaddr) | ||
83 | { | ||
84 | unsigned int i; | ||
85 | |||
86 | for (i = 0; i < server_config.max_leases; i++) | ||
87 | if (!memcmp(leases[i].chaddr, chaddr, 16)) return &(leases[i]); | ||
88 | |||
89 | return NULL; | ||
90 | } | ||
91 | |||
92 | |||
93 | /* Find the first lease that matches yiaddr, NULL is no match */ | ||
94 | struct dhcpOfferedAddr *find_lease_by_yiaddr(u_int32_t yiaddr) | ||
95 | { | ||
96 | unsigned int i; | ||
97 | |||
98 | for (i = 0; i < server_config.max_leases; i++) | ||
99 | if (leases[i].yiaddr == yiaddr) return &(leases[i]); | ||
100 | |||
101 | return NULL; | ||
102 | } | ||
103 | |||
104 | |||
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) | ||
108 | { | ||
109 | u_int32_t addr, ret; | ||
110 | struct dhcpOfferedAddr *lease = NULL; | ||
111 | |||
112 | addr = ntohl(server_config.start); /* addr is in host order here */ | ||
113 | for (;addr <= ntohl(server_config.end); addr++) { | ||
114 | |||
115 | /* ie, 192.168.55.0 */ | ||
116 | if (!(addr & 0xFF)) continue; | ||
117 | |||
118 | /* ie, 192.168.55.255 */ | ||
119 | if ((addr & 0xFF) == 0xFF) continue; | ||
120 | |||
121 | /* lease is not taken */ | ||
122 | ret = htonl(addr); | ||
123 | if ((!(lease = find_lease_by_yiaddr(ret)) || | ||
124 | |||
125 | /* or it expired and we are checking for expired leases */ | ||
126 | (check_expired && lease_expired(lease))) && | ||
127 | |||
128 | /* and it isn't on the network */ | ||
129 | !check_ip(ret)) { | ||
130 | return ret; | ||
131 | break; | ||
132 | } | ||
133 | } | ||
134 | return 0; | ||
135 | } | ||
136 | |||
137 | |||
138 | /* check is an IP is taken, if it is, add it to the lease table */ | ||
139 | int check_ip(u_int32_t addr) | ||
140 | { | ||
141 | struct in_addr temp; | ||
142 | |||
143 | if (arpping(addr, server_config.server, server_config.arp, server_config.interface) == 0) { | ||
144 | temp.s_addr = addr; | ||
145 | LOG(LOG_INFO, "%s belongs to someone, reserving it for %ld seconds", | ||
146 | inet_ntoa(temp), server_config.conflict_time); | ||
147 | add_lease(blank_chaddr, addr, server_config.conflict_time); | ||
148 | return 1; | ||
149 | } else return 0; | ||
150 | } | ||
151 | |||