Diff of /trunk/mkinitrd-magellan/busybox/networking/udhcp/leases.c

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	revision 983 by niro, Fri Apr 24 18:33:46 2009 UTC	revision 984 by niro, Sun May 30 11:32:42 2010 UTC
#	Line 2	Line 2
2	/*	/*
3	* leases.c -- tools to manage DHCP leases	* leases.c -- tools to manage DHCP leases
4	* Russ Dill <Russ.Dill@asu.edu> July 2001	* Russ Dill <Russ.Dill@asu.edu> July 2001
5		*
6		* Licensed under GPLv2, see file LICENSE in this tarball for details.
7	*/	*/
8
9	#include "common.h"	#include "common.h"
#	Line 9	Line 11
11
12
13	/* Find the oldest expired lease, NULL if there are no expired leases */	/* Find the oldest expired lease, NULL if there are no expired leases */
14	static struct dhcpOfferedAddr *oldest_expired_lease(void)	static struct dyn_lease *oldest_expired_lease(void)
15	{	{
16	struct dhcpOfferedAddr *oldest = NULL;	struct dyn_lease *oldest_lease = NULL;
17	// TODO: use monotonic_sec()	leasetime_t oldest_time = time(NULL);
	unsigned long oldest_lease = time(0);
18	unsigned i;	unsigned i;
19
20	for (i = 0; i < server_config.max_leases; i++)	/* Unexpired leases have g_leases[i].expires >= current time
21	if (oldest_lease > leases[i].expires) {	* and therefore can't ever match */
22	oldest_lease = leases[i].expires;	for (i = 0; i < server_config.max_leases; i++) {
23	oldest = &(leases[i]);	if (g_leases[i].expires < oldest_time) {
24		oldest_time = g_leases[i].expires;
25		oldest_lease = &g_leases[i];
26	}	}
27	return oldest;	}
28		return oldest_lease;
29	}	}
30
31
32	/* clear every lease out that chaddr OR yiaddr matches and is nonzero */	/* Clear every lease out that chaddr OR yiaddr matches and is nonzero */
33	static void clear_lease(const uint8_t *chaddr, uint32_t yiaddr)	static void clear_lease(const uint8_t *chaddr, uint32_t yiaddr)
34	{	{
35	unsigned i, j;	unsigned i, j;
#	Line 33  static void clear_lease(const uint8_t *c	Line 37  static void clear_lease(const uint8_t *c
37	for (j = 0; j < 16 && !chaddr[j]; j++)	for (j = 0; j < 16 && !chaddr[j]; j++)
38	continue;	continue;
39
40	for (i = 0; i < server_config.max_leases; i++)	for (i = 0; i < server_config.max_leases; i++) {
41	if ((j != 16 && memcmp(leases[i].chaddr, chaddr, 16) == 0)	if ((j != 16 && memcmp(g_leases[i].lease_mac, chaddr, 6) == 0)
42	|| (yiaddr && leases[i].yiaddr == yiaddr)	|| (yiaddr && g_leases[i].lease_nip == yiaddr)
43	) {	) {
44	memset(&(leases[i]), 0, sizeof(leases[i]));	memset(&g_leases[i], 0, sizeof(g_leases[i]));
45	}	}
46		}
47	}	}
48
49
50	/* add a lease into the table, clearing out any old ones */	/* Add a lease into the table, clearing out any old ones */
51	struct dhcpOfferedAddr* FAST_FUNC add_lease(const uint8_t *chaddr, uint32_t yiaddr, unsigned long lease)	struct dyn_lease* FAST_FUNC add_lease(
52		const uint8_t *chaddr, uint32_t yiaddr,
53		leasetime_t leasetime,
54		const char *hostname, int hostname_len)
55	{	{
56	struct dhcpOfferedAddr *oldest;	struct dyn_lease *oldest;
57
58	/* clean out any old ones */	/* clean out any old ones */
59	clear_lease(chaddr, yiaddr);	clear_lease(chaddr, yiaddr);
#	Line 53  struct dhcpOfferedAddr* FAST_FUNC add_le	Line 61  struct dhcpOfferedAddr* FAST_FUNC add_le
61	oldest = oldest_expired_lease();	oldest = oldest_expired_lease();
62
63	if (oldest) {	if (oldest) {
64	memcpy(oldest->chaddr, chaddr, 16);	oldest->hostname[0] = '\0';
65	oldest->yiaddr = yiaddr;	if (hostname) {
66	oldest->expires = time(0) + lease;	char *p;
67		if (hostname_len > sizeof(oldest->hostname))
68		hostname_len = sizeof(oldest->hostname);
69		p = safe_strncpy(oldest->hostname, hostname, hostname_len);
70		/* sanitization (s/non-ASCII/^/g) */
71		while (*p) {
72		if (*p < ' ' || *p > 126)
73		*p = '^';
74		p++;
75		}
76		}
77		memcpy(oldest->lease_mac, chaddr, 6);
78		oldest->lease_nip = yiaddr;
79		oldest->expires = time(NULL) + leasetime;
80	}	}
81
82	return oldest;	return oldest;
83	}	}
84
85
86	/* true if a lease has expired */	/* True if a lease has expired */
87	int FAST_FUNC lease_expired(struct dhcpOfferedAddr *lease)	int FAST_FUNC is_expired_lease(struct dyn_lease *lease)
88	{	{
89	return (lease->expires < (unsigned long) time(0));	return (lease->expires < (leasetime_t) time(NULL));
90	}	}
91
92
93	/* Find the first lease that matches chaddr, NULL if no match */	/* Find the first lease that matches MAC, NULL if no match */
94	struct dhcpOfferedAddr* FAST_FUNC find_lease_by_chaddr(const uint8_t *chaddr)	struct dyn_lease* FAST_FUNC find_lease_by_mac(const uint8_t *mac)
95	{	{
96	unsigned i;	unsigned i;
97
98	for (i = 0; i < server_config.max_leases; i++)	for (i = 0; i < server_config.max_leases; i++)
99	if (!memcmp(leases[i].chaddr, chaddr, 16))	if (memcmp(g_leases[i].lease_mac, mac, 6) == 0)
100	return &(leases[i]);	return &g_leases[i];
101
102	return NULL;	return NULL;
103	}	}
104
105
106	/* Find the first lease that matches yiaddr, NULL is no match */	/* Find the first lease that matches IP, NULL is no match */
107	struct dhcpOfferedAddr* FAST_FUNC find_lease_by_yiaddr(uint32_t yiaddr)	struct dyn_lease* FAST_FUNC find_lease_by_nip(uint32_t nip)
108	{	{
109	unsigned i;	unsigned i;
110
111	for (i = 0; i < server_config.max_leases; i++)	for (i = 0; i < server_config.max_leases; i++)
112	if (leases[i].yiaddr == yiaddr)	if (g_leases[i].lease_nip == nip)
113	return &(leases[i]);	return &g_leases[i];
114
115	return NULL;	return NULL;
116	}	}
117
118
119	/* check is an IP is taken, if it is, add it to the lease table */	/* Check if the IP is taken; if it is, add it to the lease table */
120	static int nobody_responds_to_arp(uint32_t addr)	static int nobody_responds_to_arp(uint32_t nip, const uint8_t *safe_mac)
121	{	{
122	/* 16 zero bytes */	/* 16 zero bytes */
123	static const uint8_t blank_chaddr[16] = { 0 };	static const uint8_t blank_chaddr[16] = { 0 };
#	Line 105  static int nobody_responds_to_arp(uint32	Line 126  static int nobody_responds_to_arp(uint32
126	struct in_addr temp;	struct in_addr temp;
127	int r;	int r;
128
129	r = arpping(addr, server_config.server, server_config.arp, server_config.interface);	r = arpping(nip, safe_mac,
130		server_config.server_nip,
131		server_config.server_mac,
132		server_config.interface);
133	if (r)	if (r)
134	return r;	return r;
135
136	temp.s_addr = addr;	temp.s_addr = nip;
137	bb_info_msg("%s belongs to someone, reserving it for %u seconds",	bb_info_msg("%s belongs to someone, reserving it for %u seconds",
138	inet_ntoa(temp), (unsigned)server_config.conflict_time);	inet_ntoa(temp), (unsigned)server_config.conflict_time);
139	add_lease(blank_chaddr, addr, server_config.conflict_time);	add_lease(blank_chaddr, nip, server_config.conflict_time, NULL, 0);
140	return 0;	return 0;
141	}	}
142
143
144	/* find an assignable address, if check_expired is true, we check all the expired leases as well.	/* Find a new usable (we think) address */
145	* Maybe this should try expired leases by age... */	uint32_t FAST_FUNC find_free_or_expired_nip(const uint8_t *safe_mac)
	uint32_t FAST_FUNC find_address(int check_expired)
146	{	{
147	uint32_t addr, ret;	uint32_t addr;
148	struct dhcpOfferedAddr *lease = NULL;	struct dyn_lease *oldest_lease = NULL;
149
150	addr = server_config.start_ip; /* addr is in host order here */	addr = server_config.start_ip; /* addr is in host order here */
151	for (; addr <= server_config.end_ip; addr++) {	for (; addr <= server_config.end_ip; addr++) {
152		uint32_t nip;
153		struct dyn_lease *lease;
154
155	/* ie, 192.168.55.0 */	/* ie, 192.168.55.0 */
156	if (!(addr & 0xFF))	if ((addr & 0xff) == 0)
157	continue;	continue;
158	/* ie, 192.168.55.255 */	/* ie, 192.168.55.255 */
159	if ((addr & 0xFF) == 0xFF)	if ((addr & 0xff) == 0xff)
160	continue;	continue;
161	/* Only do if it isn't assigned as a static lease */	nip = htonl(addr);
162	ret = htonl(addr);	/* is this a static lease addr? */
163	if (!reservedIp(server_config.static_leases, ret)) {	if (is_nip_reserved(server_config.static_leases, nip))
164	/* lease is not taken */	continue;
165	lease = find_lease_by_yiaddr(ret);
166	/* no lease or it expired and we are checking for expired leases */	lease = find_lease_by_nip(nip);
167	if ((!lease || (check_expired && lease_expired(lease)))	if (!lease) {
168	&& nobody_responds_to_arp(ret) /* it isn't used on the network */	if (nobody_responds_to_arp(nip, safe_mac))
169	) {	return nip;
170	return ret;	} else {
171	}	if (!oldest_lease || lease->expires < oldest_lease->expires)
172		oldest_lease = lease;
173	}	}
174	}	}
175
176		if (oldest_lease && is_expired_lease(oldest_lease)
177		&& nobody_responds_to_arp(oldest_lease->lease_nip, safe_mac)
178		) {
179		return oldest_lease->lease_nip;
180		}
181
182	return 0;	return 0;
183	}	}

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