networking/udhcp/files.c

/* vi: set sw=4 ts=4: */
/*
 * files.c -- DHCP server file manipulation *
 * Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001
 *
 * Licensed under GPLv2, see file LICENSE in this tarball for details.
 */

#include <netinet/ether.h>

#include "common.h"
#include "dhcpd.h"
#include "options.h"

#if BB_LITTLE_ENDIAN
static inline uint64_t hton64(uint64_t v)
{
        return (((uint64_t)htonl(v)) << 32) | htonl(v >> 32);
}
#else
#define hton64(v) (v)
#endif
#define ntoh64(v) hton64(v)


/* on these functions, make sure your datatype matches */
static int FAST_FUNC read_nip(const char *line, void *arg)
{
	len_and_sockaddr *lsa;

	lsa = host_and_af2sockaddr(line, 0, AF_INET);
	if (!lsa)
		return 0;
	*(uint32_t*)arg = lsa->u.sin.sin_addr.s_addr;
	free(lsa);
	return 1;
}


static int FAST_FUNC read_mac(const char *line, void *arg)
{
	return NULL == ether_aton_r(line, (struct ether_addr *)arg);
}


static int FAST_FUNC read_str(const char *line, void *arg)
{
	char **dest = arg;

	free(*dest);
	*dest = xstrdup(line);
	return 1;
}


static int FAST_FUNC read_u32(const char *line, void *arg)
{
	*(uint32_t*)arg = bb_strtou32(line, NULL, 10);
	return errno == 0;
}


static int FAST_FUNC read_yn(const char *line, void *arg)
{
	char *dest = arg;

	if (!strcasecmp("yes", line)) {
		*dest = 1;
		return 1;
	}
	if (!strcasecmp("no", line)) {
		*dest = 0;
		return 1;
	}
	return 0;
}


/* find option 'code' in opt_list */
struct option_set* FAST_FUNC find_option(struct option_set *opt_list, uint8_t code)
{
	while (opt_list && opt_list->data[OPT_CODE] < code)
		opt_list = opt_list->next;

	if (opt_list && opt_list->data[OPT_CODE] == code)
		return opt_list;
	return NULL;
}


/* add an option to the opt_list */
static void attach_option(struct option_set **opt_list,
		const struct dhcp_option *option, char *buffer, int length)
{
	struct option_set *existing, *new, **curr;

	existing = find_option(*opt_list, option->code);
	if (!existing) {
		log2("Attaching option %02x to list", option->code);

#if ENABLE_FEATURE_UDHCP_RFC3397
		if ((option->flags & TYPE_MASK) == OPTION_STR1035)
			/* reuse buffer and length for RFC1035-formatted string */
			buffer = (char *)dname_enc(NULL, 0, buffer, &length);
#endif

		/* make a new option */
		new = xmalloc(sizeof(*new));
		new->data = xmalloc(length + 2);
		new->data[OPT_CODE] = option->code;
		new->data[OPT_LEN] = length;
		memcpy(new->data + 2, buffer, length);

		curr = opt_list;
		while (*curr && (*curr)->data[OPT_CODE] < option->code)
			curr = &(*curr)->next;

		new->next = *curr;
		*curr = new;
#if ENABLE_FEATURE_UDHCP_RFC3397
		if ((option->flags & TYPE_MASK) == OPTION_STR1035 && buffer != NULL)
			free(buffer);
#endif
		return;
	}

	/* add it to an existing option */
	log1("Attaching option %02x to existing member of list", option->code);
	if (option->flags & OPTION_LIST) {
#if ENABLE_FEATURE_UDHCP_RFC3397
		if ((option->flags & TYPE_MASK) == OPTION_STR1035)
			/* reuse buffer and length for RFC1035-formatted string */
			buffer = (char *)dname_enc(existing->data + 2,
					existing->data[OPT_LEN], buffer, &length);
#endif
		if (existing->data[OPT_LEN] + length <= 255) {
			existing->data = xrealloc(existing->data,
					existing->data[OPT_LEN] + length + 3);
			if ((option->flags & TYPE_MASK) == OPTION_STRING) {
				/* ' ' can bring us to 256 - bad */
				if (existing->data[OPT_LEN] + length >= 255)
					return;
				/* add space separator between STRING options in a list */
				existing->data[existing->data[OPT_LEN] + 2] = ' ';
				existing->data[OPT_LEN]++;
			}
			memcpy(existing->data + existing->data[OPT_LEN] + 2, buffer, length);
			existing->data[OPT_LEN] += length;
		} /* else, ignore the data, we could put this in a second option in the future */
#if ENABLE_FEATURE_UDHCP_RFC3397
		if ((option->flags & TYPE_MASK) == OPTION_STR1035 && buffer != NULL)
			free(buffer);
#endif
	} /* else, ignore the new data */
}


/* read a dhcp option and add it to opt_list */
static int FAST_FUNC read_opt(const char *const_line, void *arg)
{
	struct option_set **opt_list = arg;
	char *opt, *val, *endptr;
	char *line;
	const struct dhcp_option *option;
	int retval, length, idx;
	char buffer[8] ALIGNED(4);
	uint16_t *result_u16 = (uint16_t *) buffer;
	uint32_t *result_u32 = (uint32_t *) buffer;

	/* Cheat, the only const line we'll actually get is "" */
	line = (char *) const_line;
	opt = strtok(line, " \t=");
	if (!opt)
		return 0;

	idx = index_in_strings(dhcp_option_strings, opt); /* NB: was strcasecmp! */
	if (idx < 0)
		return 0;
	option = &dhcp_options[idx];

	retval = 0;
	do {
		val = strtok(NULL, ", \t");
		if (!val) break;
		length = dhcp_option_lengths[option->flags & TYPE_MASK];
		retval = 0;
		opt = buffer; /* new meaning for variable opt */
		switch (option->flags & TYPE_MASK) {
		case OPTION_IP:
			retval = read_nip(val, buffer);
			break;
		case OPTION_IP_PAIR:
			retval = read_nip(val, buffer);
			val = strtok(NULL, ", \t/-");
			if (!val)
				retval = 0;
			if (retval)
				retval = read_nip(val, buffer + 4);
			break;
		case OPTION_STRING:
#if ENABLE_FEATURE_UDHCP_RFC3397
		case OPTION_STR1035:
#endif
			length = strlen(val);
			if (length > 0) {
				if (length > 254) length = 254;
				opt = val;
				retval = 1;
			}
			break;
		case OPTION_BOOLEAN:
			retval = read_yn(val, buffer);
			break;
		case OPTION_U8:
			buffer[0] = strtoul(val, &endptr, 0);
			retval = (endptr[0] == '\0');
			break;
		/* htonX are macros in older libc's, using temp var
		 * in code below for safety */
		/* TODO: use bb_strtoX? */
		case OPTION_U16: {
			unsigned long tmp = strtoul(val, &endptr, 0);
			*result_u16 = htons(tmp);
			retval = (endptr[0] == '\0' /*&& tmp < 0x10000*/);
			break;
		}
		case OPTION_S16: {
			long tmp = strtol(val, &endptr, 0);
			*result_u16 = htons(tmp);
			retval = (endptr[0] == '\0');
			break;
		}
		case OPTION_U32: {
			unsigned long tmp = strtoul(val, &endptr, 0);
			*result_u32 = htonl(tmp);
			retval = (endptr[0] == '\0');
			break;
		}
		case OPTION_S32: {
			long tmp = strtol(val, &endptr, 0);
			*result_u32 = htonl(tmp);
			retval = (endptr[0] == '\0');
			break;
		}
		default:
			break;
		}
		if (retval)
			attach_option(opt_list, option, opt, length);
	} while (retval && option->flags & OPTION_LIST);
	return retval;
}

static int FAST_FUNC read_staticlease(const char *const_line, void *arg)
{
	char *line;
	char *mac_string;
	char *ip_string;
	struct ether_addr mac_bytes;
	uint32_t ip;

	/* Read mac */
	line = (char *) const_line;
	mac_string = strtok_r(line, " \t", &line);
	read_mac(mac_string, &mac_bytes);

	/* Read ip */
	ip_string = strtok_r(NULL, " \t", &line);
	read_nip(ip_string, &ip);

	add_static_lease(arg, (uint8_t*) &mac_bytes, ip);

	log_static_leases(arg);

	return 1;
}


struct config_keyword {
	const char *keyword;
	int (*handler)(const char *line, void *var) FAST_FUNC;
	void *var;
	const char *def;
};

static const struct config_keyword keywords[] = {
	/* keyword       handler   variable address               default */
	{"start",        read_nip, &(server_config.start_ip),     "192.168.0.20"},
	{"end",          read_nip, &(server_config.end_ip),       "192.168.0.254"},
	{"interface",    read_str, &(server_config.interface),    "eth0"},
	/* Avoid "max_leases value not sane" warning by setting default
	 * to default_end_ip - default_start_ip + 1: */
	{"max_leases",   read_u32, &(server_config.max_leases),   "235"},
	{"auto_time",    read_u32, &(server_config.auto_time),    "7200"},
	{"decline_time", read_u32, &(server_config.decline_time), "3600"},
	{"conflict_time",read_u32, &(server_config.conflict_time),"3600"},
	{"offer_time",   read_u32, &(server_config.offer_time),   "60"},
	{"min_lease",    read_u32, &(server_config.min_lease_sec),"60"},
	{"lease_file",   read_str, &(server_config.lease_file),   LEASES_FILE},
	{"pidfile",      read_str, &(server_config.pidfile),      "/var/run/udhcpd.pid"},
	{"siaddr",       read_nip, &(server_config.siaddr_nip),   "0.0.0.0"},
	/* keywords with no defaults must be last! */
	{"option",       read_opt, &(server_config.options),      ""},
	{"opt",          read_opt, &(server_config.options),      ""},
	{"notify_file",  read_str, &(server_config.notify_file),  ""},
	{"sname",        read_str, &(server_config.sname),        ""},
	{"boot_file",    read_str, &(server_config.boot_file),    ""},
	{"static_lease", read_staticlease, &(server_config.static_leases), ""},
};
enum { KWS_WITH_DEFAULTS = ARRAY_SIZE(keywords) - 6 };

void FAST_FUNC read_config(const char *file)
{
	parser_t *parser;
	const struct config_keyword *k;
	unsigned i;
	char *token[2];

	for (i = 0; i < KWS_WITH_DEFAULTS; i++)
		keywords[i].handler(keywords[i].def, keywords[i].var);

	parser = config_open(file);
	while (config_read(parser, token, 2, 2, "# \t", PARSE_NORMAL)) {
		for (k = keywords, i = 0; i < ARRAY_SIZE(keywords); k++, i++) {
			if (!strcasecmp(token[0], k->keyword)) {
				if (!k->handler(token[1], k->var)) {
					bb_error_msg("can't parse line %u in %s",
							parser->lineno, file);
					/* reset back to the default value */
					k->handler(k->def, k->var);
				}
				break;
			}
		}
	}
	config_close(parser);

	server_config.start_ip = ntohl(server_config.start_ip);
	server_config.end_ip = ntohl(server_config.end_ip);
}


void FAST_FUNC write_leases(void)
{
	int fd;
	unsigned i;
	leasetime_t curr;
	int64_t written_at;

	fd = open_or_warn(server_config.lease_file, O_WRONLY|O_CREAT|O_TRUNC);
	if (fd < 0)
		return;

	curr = written_at = time(NULL);

	written_at = hton64(written_at);
	full_write(fd, &written_at, sizeof(written_at));

	for (i = 0; i < server_config.max_leases; i++) {
		leasetime_t tmp_time;

		if (g_leases[i].lease_nip == 0)
			continue;

		/* Screw with the time in the struct, for easier writing */
		tmp_time = g_leases[i].expires;

		g_leases[i].expires -= curr;
		if ((signed_leasetime_t) g_leases[i].expires < 0)
			g_leases[i].expires = 0;
		g_leases[i].expires = htonl(g_leases[i].expires);

		/* No error check. If the file gets truncated,
		 * we lose some leases on restart. Oh well. */
		full_write(fd, &g_leases[i], sizeof(g_leases[i]));

		/* Then restore it when done */
		g_leases[i].expires = tmp_time;
	}
	close(fd);

	if (server_config.notify_file) {
// TODO: vfork-based child creation
		char *cmd = xasprintf("%s %s", server_config.notify_file, server_config.lease_file);
		system(cmd);
		free(cmd);
	}
}


void FAST_FUNC read_leases(const char *file)
{
	struct dyn_lease lease;
	int64_t written_at, time_passed;
	int fd;
#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
	unsigned i = 0;
#endif

	fd = open_or_warn(file, O_RDONLY);
	if (fd < 0)
		return;

	if (full_read(fd, &written_at, sizeof(written_at)) != sizeof(written_at))
		goto ret;
	written_at = ntoh64(written_at);

	time_passed = time(NULL) - written_at;
	/* Strange written_at, or lease file from old version of udhcpd
	 * which had no "written_at" field? */
	if ((uint64_t)time_passed > 12 * 60 * 60)
		goto ret;

	while (full_read(fd, &lease, sizeof(lease)) == sizeof(lease)) {
//FIXME: what if it matches some static lease?
		uint32_t y = ntohl(lease.lease_nip);
		if (y >= server_config.start_ip && y <= server_config.end_ip) {
			signed_leasetime_t expires = ntohl(lease.expires) - (signed_leasetime_t)time_passed;
			if (expires <= 0)
				continue;
			/* NB: add_lease takes "relative time", IOW,
			 * lease duration, not lease deadline. */
			if (add_lease(lease.lease_mac, lease.lease_nip,
					expires,
					lease.hostname, sizeof(lease.hostname)
				) == 0
			) {
				bb_error_msg("too many leases while loading %s", file);
				break;
			}
#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
			i++;
#endif
		}
	}
	log1("Read %d leases", i);
 ret:
	close(fd);
}
1	/* vi: set sw=4 ts=4: */
2	/*
3	* files.c -- DHCP server file manipulation *
4	* Rewrite by 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 <netinet/ether.h>
10
11	#include "common.h"
12	#include "dhcpd.h"
13	#include "options.h"
14
15	#if BB_LITTLE_ENDIAN
16	static inline uint64_t hton64(uint64_t v)
17	{
18	return (((uint64_t)htonl(v)) << 32) \| htonl(v >> 32);
19	}
20	#else
21	#define hton64(v) (v)
22	#endif
23	#define ntoh64(v) hton64(v)
24
25
26	/* on these functions, make sure your datatype matches */
27	static int FAST_FUNC read_nip(const char line, void arg)
28	{
29	len_and_sockaddr *lsa;
30
31	lsa = host_and_af2sockaddr(line, 0, AF_INET);
32	if (!lsa)
33	return 0;
34	(uint32_t)arg = lsa->u.sin.sin_addr.s_addr;
35	free(lsa);
36	return 1;
37	}
38
39
40	static int FAST_FUNC read_mac(const char line, void arg)
41	{
42	return NULL == ether_aton_r(line, (struct ether_addr *)arg);
43	}
44
45
46	static int FAST_FUNC read_str(const char line, void arg)
47	{
48	char **dest = arg;
49
50	free(*dest);
51	*dest = xstrdup(line);
52	return 1;
53	}
54
55
56	static int FAST_FUNC read_u32(const char line, void arg)
57	{
58	(uint32_t)arg = bb_strtou32(line, NULL, 10);
59	return errno == 0;
60	}
61
62
63	static int FAST_FUNC read_yn(const char line, void arg)
64	{
65	char *dest = arg;
66
67	if (!strcasecmp("yes", line)) {
68	*dest = 1;
69	return 1;
70	}
71	if (!strcasecmp("no", line)) {
72	*dest = 0;
73	return 1;
74	}
75	return 0;
76	}
77
78
79	/* find option 'code' in opt_list */
80	struct option_set* FAST_FUNC find_option(struct option_set *opt_list, uint8_t code)
81	{
82	while (opt_list && opt_list->data[OPT_CODE] < code)
83	opt_list = opt_list->next;
84
85	if (opt_list && opt_list->data[OPT_CODE] == code)
86	return opt_list;
87	return NULL;
88	}
89
90
91	/* add an option to the opt_list */
92	static void attach_option(struct option_set **opt_list,
93	const struct dhcp_option option, char buffer, int length)
94	{
95	struct option_set existing, new, **curr;
96
97	existing = find_option(*opt_list, option->code);
98	if (!existing) {
99	log2("Attaching option %02x to list", option->code);
100
101	#if ENABLE_FEATURE_UDHCP_RFC3397
102	if ((option->flags & TYPE_MASK) == OPTION_STR1035)
103	/* reuse buffer and length for RFC1035-formatted string */
104	buffer = (char *)dname_enc(NULL, 0, buffer, &length);
105	#endif
106
107	/* make a new option */
108	new = xmalloc(sizeof(*new));
109	new->data = xmalloc(length + 2);
110	new->data[OPT_CODE] = option->code;
111	new->data[OPT_LEN] = length;
112	memcpy(new->data + 2, buffer, length);
113
114	curr = opt_list;
115	while (curr && (curr)->data[OPT_CODE] < option->code)
116	curr = &(*curr)->next;
117
118	new->next = *curr;
119	*curr = new;
120	#if ENABLE_FEATURE_UDHCP_RFC3397
121	if ((option->flags & TYPE_MASK) == OPTION_STR1035 && buffer != NULL)
122	free(buffer);
123	#endif
124	return;
125	}
126
127	/* add it to an existing option */
128	log1("Attaching option %02x to existing member of list", option->code);
129	if (option->flags & OPTION_LIST) {
130	#if ENABLE_FEATURE_UDHCP_RFC3397
131	if ((option->flags & TYPE_MASK) == OPTION_STR1035)
132	/* reuse buffer and length for RFC1035-formatted string */
133	buffer = (char *)dname_enc(existing->data + 2,
134	existing->data[OPT_LEN], buffer, &length);
135	#endif
136	if (existing->data[OPT_LEN] + length <= 255) {
137	existing->data = xrealloc(existing->data,
138	existing->data[OPT_LEN] + length + 3);
139	if ((option->flags & TYPE_MASK) == OPTION_STRING) {
140	/* ' ' can bring us to 256 - bad */
141	if (existing->data[OPT_LEN] + length >= 255)
142	return;
143	/* add space separator between STRING options in a list */
144	existing->data[existing->data[OPT_LEN] + 2] = ' ';
145	existing->data[OPT_LEN]++;
146	}
147	memcpy(existing->data + existing->data[OPT_LEN] + 2, buffer, length);
148	existing->data[OPT_LEN] += length;
149	} /* else, ignore the data, we could put this in a second option in the future */
150	#if ENABLE_FEATURE_UDHCP_RFC3397
151	if ((option->flags & TYPE_MASK) == OPTION_STR1035 && buffer != NULL)
152	free(buffer);
153	#endif
154	} /* else, ignore the new data */
155	}
156
157
158	/* read a dhcp option and add it to opt_list */
159	static int FAST_FUNC read_opt(const char const_line, void arg)
160	{
161	struct option_set **opt_list = arg;
162	char opt, val, *endptr;
163	char *line;
164	const struct dhcp_option *option;
165	int retval, length, idx;
166	char buffer[8] ALIGNED(4);
167	uint16_t result_u16 = (uint16_t ) buffer;
168	uint32_t result_u32 = (uint32_t ) buffer;
169
170	/* Cheat, the only const line we'll actually get is "" */
171	line = (char *) const_line;
172	opt = strtok(line, " \t=");
173	if (!opt)
174	return 0;
175
176	idx = index_in_strings(dhcp_option_strings, opt); /* NB: was strcasecmp! */
177	if (idx < 0)
178	return 0;
179	option = &dhcp_options[idx];
180
181	retval = 0;
182	do {
183	val = strtok(NULL, ", \t");
184	if (!val) break;
185	length = dhcp_option_lengths[option->flags & TYPE_MASK];
186	retval = 0;
187	opt = buffer; /* new meaning for variable opt */
188	switch (option->flags & TYPE_MASK) {
189	case OPTION_IP:
190	retval = read_nip(val, buffer);
191	break;
192	case OPTION_IP_PAIR:
193	retval = read_nip(val, buffer);
194	val = strtok(NULL, ", \t/-");
195	if (!val)
196	retval = 0;
197	if (retval)
198	retval = read_nip(val, buffer + 4);
199	break;
200	case OPTION_STRING:
201	#if ENABLE_FEATURE_UDHCP_RFC3397
202	case OPTION_STR1035:
203	#endif
204	length = strlen(val);
205	if (length > 0) {
206	if (length > 254) length = 254;
207	opt = val;
208	retval = 1;
209	}
210	break;
211	case OPTION_BOOLEAN:
212	retval = read_yn(val, buffer);
213	break;
214	case OPTION_U8:
215	buffer[0] = strtoul(val, &endptr, 0);
216	retval = (endptr[0] == '\0');
217	break;
218	/* htonX are macros in older libc's, using temp var
219	* in code below for safety */
220	/* TODO: use bb_strtoX? */
221	case OPTION_U16: {
222	unsigned long tmp = strtoul(val, &endptr, 0);
223	*result_u16 = htons(tmp);
224	retval = (endptr[0] == '\0' /&& tmp < 0x10000/);
225	break;
226	}
227	case OPTION_S16: {
228	long tmp = strtol(val, &endptr, 0);
229	*result_u16 = htons(tmp);
230	retval = (endptr[0] == '\0');
231	break;
232	}
233	case OPTION_U32: {
234	unsigned long tmp = strtoul(val, &endptr, 0);
235	*result_u32 = htonl(tmp);
236	retval = (endptr[0] == '\0');
237	break;
238	}
239	case OPTION_S32: {
240	long tmp = strtol(val, &endptr, 0);
241	*result_u32 = htonl(tmp);
242	retval = (endptr[0] == '\0');
243	break;
244	}
245	default:
246	break;
247	}
248	if (retval)
249	attach_option(opt_list, option, opt, length);
250	} while (retval && option->flags & OPTION_LIST);
251	return retval;
252	}
253
254	static int FAST_FUNC read_staticlease(const char const_line, void arg)
255	{
256	char *line;
257	char *mac_string;
258	char *ip_string;
259	struct ether_addr mac_bytes;
260	uint32_t ip;
261
262	/* Read mac */
263	line = (char *) const_line;
264	mac_string = strtok_r(line, " \t", &line);
265	read_mac(mac_string, &mac_bytes);
266
267	/* Read ip */
268	ip_string = strtok_r(NULL, " \t", &line);
269	read_nip(ip_string, &ip);
270
271	add_static_lease(arg, (uint8_t*) &mac_bytes, ip);
272
273	log_static_leases(arg);
274
275	return 1;
276	}
277
278
279	struct config_keyword {
280	const char *keyword;
281	int (handler)(const char line, void *var) FAST_FUNC;
282	void *var;
283	const char *def;
284	};
285
286	static const struct config_keyword keywords[] = {
287	/* keyword handler variable address default */
288	{"start", read_nip, &(server_config.start_ip), "192.168.0.20"},
289	{"end", read_nip, &(server_config.end_ip), "192.168.0.254"},
290	{"interface", read_str, &(server_config.interface), "eth0"},
291	/* Avoid "max_leases value not sane" warning by setting default
292	* to default_end_ip - default_start_ip + 1: */
293	{"max_leases", read_u32, &(server_config.max_leases), "235"},
294	{"auto_time", read_u32, &(server_config.auto_time), "7200"},
295	{"decline_time", read_u32, &(server_config.decline_time), "3600"},
296	{"conflict_time",read_u32, &(server_config.conflict_time),"3600"},
297	{"offer_time", read_u32, &(server_config.offer_time), "60"},
298	{"min_lease", read_u32, &(server_config.min_lease_sec),"60"},
299	{"lease_file", read_str, &(server_config.lease_file), LEASES_FILE},
300	{"pidfile", read_str, &(server_config.pidfile), "/var/run/udhcpd.pid"},
301	{"siaddr", read_nip, &(server_config.siaddr_nip), "0.0.0.0"},
302	/* keywords with no defaults must be last! */
303	{"option", read_opt, &(server_config.options), ""},
304	{"opt", read_opt, &(server_config.options), ""},
305	{"notify_file", read_str, &(server_config.notify_file), ""},
306	{"sname", read_str, &(server_config.sname), ""},
307	{"boot_file", read_str, &(server_config.boot_file), ""},
308	{"static_lease", read_staticlease, &(server_config.static_leases), ""},
309	};
310	enum { KWS_WITH_DEFAULTS = ARRAY_SIZE(keywords) - 6 };
311
312	void FAST_FUNC read_config(const char *file)
313	{
314	parser_t *parser;
315	const struct config_keyword *k;
316	unsigned i;
317	char *token[2];
318
319	for (i = 0; i < KWS_WITH_DEFAULTS; i++)
320	keywords[i].handler(keywords[i].def, keywords[i].var);
321
322	parser = config_open(file);
323	while (config_read(parser, token, 2, 2, "# \t", PARSE_NORMAL)) {
324	for (k = keywords, i = 0; i < ARRAY_SIZE(keywords); k++, i++) {
325	if (!strcasecmp(token[0], k->keyword)) {
326	if (!k->handler(token[1], k->var)) {
327	bb_error_msg("can't parse line %u in %s",
328	parser->lineno, file);
329	/* reset back to the default value */
330	k->handler(k->def, k->var);
331	}
332	break;
333	}
334	}
335	}
336	config_close(parser);
337
338	server_config.start_ip = ntohl(server_config.start_ip);
339	server_config.end_ip = ntohl(server_config.end_ip);
340	}
341
342
343	void FAST_FUNC write_leases(void)
344	{
345	int fd;
346	unsigned i;
347	leasetime_t curr;
348	int64_t written_at;
349
350	fd = open_or_warn(server_config.lease_file, O_WRONLY\|O_CREAT\|O_TRUNC);
351	if (fd < 0)
352	return;
353
354	curr = written_at = time(NULL);
355
356	written_at = hton64(written_at);
357	full_write(fd, &written_at, sizeof(written_at));
358
359	for (i = 0; i < server_config.max_leases; i++) {
360	leasetime_t tmp_time;
361
362	if (g_leases[i].lease_nip == 0)
363	continue;
364
365	/* Screw with the time in the struct, for easier writing */
366	tmp_time = g_leases[i].expires;
367
368	g_leases[i].expires -= curr;
369	if ((signed_leasetime_t) g_leases[i].expires < 0)
370	g_leases[i].expires = 0;
371	g_leases[i].expires = htonl(g_leases[i].expires);
372
373	/* No error check. If the file gets truncated,
374	* we lose some leases on restart. Oh well. */
375	full_write(fd, &g_leases[i], sizeof(g_leases[i]));
376
377	/* Then restore it when done */
378	g_leases[i].expires = tmp_time;
379	}
380	close(fd);
381
382	if (server_config.notify_file) {
383	// TODO: vfork-based child creation
384	char *cmd = xasprintf("%s %s", server_config.notify_file, server_config.lease_file);
385	system(cmd);
386	free(cmd);
387	}
388	}
389
390
391	void FAST_FUNC read_leases(const char *file)
392	{
393	struct dyn_lease lease;
394	int64_t written_at, time_passed;
395	int fd;
396	#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
397	unsigned i = 0;
398	#endif
399
400	fd = open_or_warn(file, O_RDONLY);
401	if (fd < 0)
402	return;
403
404	if (full_read(fd, &written_at, sizeof(written_at)) != sizeof(written_at))
405	goto ret;
406	written_at = ntoh64(written_at);
407
408	time_passed = time(NULL) - written_at;
409	/* Strange written_at, or lease file from old version of udhcpd
410	* which had no "written_at" field? */
411	if ((uint64_t)time_passed > 12 * 60 * 60)
412	goto ret;
413
414	while (full_read(fd, &lease, sizeof(lease)) == sizeof(lease)) {
415	//FIXME: what if it matches some static lease?
416	uint32_t y = ntohl(lease.lease_nip);
417	if (y >= server_config.start_ip && y <= server_config.end_ip) {
418	signed_leasetime_t expires = ntohl(lease.expires) - (signed_leasetime_t)time_passed;
419	if (expires <= 0)
420	continue;
421	/* NB: add_lease takes "relative time", IOW,
422	* lease duration, not lease deadline. */
423	if (add_lease(lease.lease_mac, lease.lease_nip,
424	expires,
425	lease.hostname, sizeof(lease.hostname)
426	) == 0
427	) {
428	bb_error_msg("too many leases while loading %s", file);
429	break;
430	}
431	#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
432	i++;
433	#endif
434	}
435	}
436	log1("Read %d leases", i);
437	ret:
438	close(fd);
439	}