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-rw-r--r--networking/udhcp/leases.c211
1 files changed, 0 insertions, 211 deletions
diff --git a/networking/udhcp/leases.c b/networking/udhcp/leases.c
deleted file mode 100644
index 6642e396d..000000000
--- a/networking/udhcp/leases.c
+++ /dev/null
@@ -1,211 +0,0 @@
1/* vi: set sw=4 ts=4: */
2/*
3 * Russ Dill <Russ.Dill@asu.edu> July 2001
4 *
5 * Licensed under GPLv2, see file LICENSE in this source tree.
6 */
7#include "common.h"
8#include "dhcpd.h"
9
10/* Find the oldest expired lease, NULL if there are no expired leases */
11static struct dyn_lease *oldest_expired_lease(void)
12{
13 struct dyn_lease *oldest_lease = NULL;
14 leasetime_t oldest_time = time(NULL);
15 unsigned i;
16
17 /* Unexpired leases have g_leases[i].expires >= current time
18 * and therefore can't ever match */
19 for (i = 0; i < server_config.max_leases; i++) {
20 if (g_leases[i].expires == 0 /* empty entry */
21 || g_leases[i].expires < oldest_time
22 ) {
23 oldest_time = g_leases[i].expires;
24 oldest_lease = &g_leases[i];
25 }
26 }
27 return oldest_lease;
28}
29
30/* Clear out all leases with matching nonzero chaddr OR yiaddr.
31 * If chaddr == NULL, this is a conflict lease.
32 */
33static void clear_leases(const uint8_t *chaddr, uint32_t yiaddr)
34{
35 unsigned i;
36
37 for (i = 0; i < server_config.max_leases; i++) {
38 if ((chaddr && memcmp(g_leases[i].lease_mac, chaddr, 6) == 0)
39 || (yiaddr && g_leases[i].lease_nip == yiaddr)
40 ) {
41 memset(&g_leases[i], 0, sizeof(g_leases[i]));
42 }
43 }
44}
45
46/* Add a lease into the table, clearing out any old ones.
47 * If chaddr == NULL, this is a conflict lease.
48 */
49struct dyn_lease* FAST_FUNC add_lease(
50 const uint8_t *chaddr, uint32_t yiaddr,
51 leasetime_t leasetime,
52 const char *hostname, int hostname_len)
53{
54 struct dyn_lease *oldest;
55
56 /* clean out any old ones */
57 clear_leases(chaddr, yiaddr);
58
59 oldest = oldest_expired_lease();
60
61 if (oldest) {
62 memset(oldest, 0, sizeof(*oldest));
63 if (hostname) {
64 char *p;
65
66 hostname_len++; /* include NUL */
67 if (hostname_len > sizeof(oldest->hostname))
68 hostname_len = sizeof(oldest->hostname);
69 p = safe_strncpy(oldest->hostname, hostname, hostname_len);
70 /*
71 * Sanitization (s/bad_char/./g).
72 * The intent is not to allow only "DNS-valid" hostnames,
73 * but merely make dumpleases output safe for shells to use.
74 * We accept "0-9A-Za-z._-", all other chars turn to dots.
75 */
76 while (*p) {
77 if (!isalnum(*p) && *p != '-' && *p != '_')
78 *p = '.';
79 p++;
80 }
81 }
82 if (chaddr)
83 memcpy(oldest->lease_mac, chaddr, 6);
84 oldest->lease_nip = yiaddr;
85 oldest->expires = time(NULL) + leasetime;
86 }
87
88 return oldest;
89}
90
91/* True if a lease has expired */
92int FAST_FUNC is_expired_lease(struct dyn_lease *lease)
93{
94 return (lease->expires < (leasetime_t) time(NULL));
95}
96
97/* Find the first lease that matches MAC, NULL if no match */
98struct dyn_lease* FAST_FUNC find_lease_by_mac(const uint8_t *mac)
99{
100 unsigned i;
101
102 for (i = 0; i < server_config.max_leases; i++)
103 if (memcmp(g_leases[i].lease_mac, mac, 6) == 0)
104 return &g_leases[i];
105
106 return NULL;
107}
108
109/* Find the first lease that matches IP, NULL is no match */
110struct dyn_lease* FAST_FUNC find_lease_by_nip(uint32_t nip)
111{
112 unsigned i;
113
114 for (i = 0; i < server_config.max_leases; i++)
115 if (g_leases[i].lease_nip == nip)
116 return &g_leases[i];
117
118 return NULL;
119}
120
121/* Check if the IP is taken; if it is, add it to the lease table */
122static int nobody_responds_to_arp(uint32_t nip, const uint8_t *safe_mac, unsigned arpping_ms)
123{
124 struct in_addr temp;
125 int r;
126
127 r = arpping(nip, safe_mac,
128 server_config.server_nip,
129 server_config.server_mac,
130 server_config.interface,
131 arpping_ms);
132 if (r)
133 return r;
134
135 temp.s_addr = nip;
136 bb_error_msg("%s belongs to someone, reserving it for %u seconds",
137 inet_ntoa(temp), (unsigned)server_config.conflict_time);
138 add_lease(NULL, nip, server_config.conflict_time, NULL, 0);
139 return 0;
140}
141
142/* Find a new usable (we think) address */
143uint32_t FAST_FUNC find_free_or_expired_nip(const uint8_t *safe_mac, unsigned arpping_ms)
144{
145 uint32_t addr;
146 struct dyn_lease *oldest_lease = NULL;
147
148#if ENABLE_FEATURE_UDHCPD_BASE_IP_ON_MAC
149 uint32_t stop;
150 unsigned i, hash;
151
152 /* hash hwaddr: use the SDBM hashing algorithm. Seems to give good
153 * dispersal even with similarly-valued "strings".
154 */
155 hash = 0;
156 for (i = 0; i < 6; i++)
157 hash += safe_mac[i] + (hash << 6) + (hash << 16) - hash;
158
159 /* pick a seed based on hwaddr then iterate until we find a free address. */
160 addr = server_config.start_ip
161 + (hash % (1 + server_config.end_ip - server_config.start_ip));
162 stop = addr;
163#else
164 addr = server_config.start_ip;
165#define stop (server_config.end_ip + 1)
166#endif
167 do {
168 uint32_t nip;
169 struct dyn_lease *lease;
170
171 /* ie, 192.168.55.0 */
172 if ((addr & 0xff) == 0)
173 goto next_addr;
174 /* ie, 192.168.55.255 */
175 if ((addr & 0xff) == 0xff)
176 goto next_addr;
177 nip = htonl(addr);
178 /* skip our own address */
179 if (nip == server_config.server_nip)
180 goto next_addr;
181 /* is this a static lease addr? */
182 if (is_nip_reserved(server_config.static_leases, nip))
183 goto next_addr;
184
185 lease = find_lease_by_nip(nip);
186 if (!lease) {
187//TODO: DHCP servers do not always sit on the same subnet as clients: should *ping*, not arp-ping!
188 if (nobody_responds_to_arp(nip, safe_mac, arpping_ms))
189 return nip;
190 } else {
191 if (!oldest_lease || lease->expires < oldest_lease->expires)
192 oldest_lease = lease;
193 }
194
195 next_addr:
196 addr++;
197#if ENABLE_FEATURE_UDHCPD_BASE_IP_ON_MAC
198 if (addr > server_config.end_ip)
199 addr = server_config.start_ip;
200#endif
201 } while (addr != stop);
202
203 if (oldest_lease
204 && is_expired_lease(oldest_lease)
205 && nobody_responds_to_arp(oldest_lease->lease_nip, safe_mac, arpping_ms)
206 ) {
207 return oldest_lease->lease_nip;
208 }
209
210 return 0;
211}
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