aboutsummaryrefslogtreecommitdiff
path: root/networking/udhcp/files.c
blob: b7bad3309a0d716f6e386afabfc17a801af77796 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
/* vi: set sw=4 ts=4: */
/*
 * files.c -- DHCP server file manipulation *
 * Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001
 */

#include <netinet/ether.h>

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


/* on these functions, make sure your datatype matches */
static int read_ip(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 read_mac(const char *line, void *arg)
{
	struct ether_addr *temp_ether_addr;

	temp_ether_addr = ether_aton_r(line, (struct ether_addr *)arg);
	if (temp_ether_addr == NULL)
		return 0;
	return 1;
}


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

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


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


static int 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) {
		DEBUG("Attaching option %02x to list", option->code);

#if ENABLE_FEATURE_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_RFC3397
		if ((option->flags & TYPE_MASK) == OPTION_STR1035 && buffer != NULL)
			free(buffer);
#endif
		return;
	}

	/* add it to an existing option */
	DEBUG("Attaching option %02x to existing member of list", option->code);
	if (option->flags & OPTION_LIST) {
#if ENABLE_FEATURE_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_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 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_ip(val, buffer);
			break;
		case OPTION_IP_PAIR:
			retval = read_ip(val, buffer);
			val = strtok(NULL, ", \t/-");
			if (!val)
				retval = 0;
			if (retval)
				retval = read_ip(val, buffer + 4);
			break;
		case OPTION_STRING:
#if ENABLE_FEATURE_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 read_staticlease(const char *const_line, void *arg)
{
	char *line;
	char *mac_string;
	char *ip_string;
	uint8_t *mac_bytes;
	uint32_t *ip;

	/* Allocate memory for addresses */
	mac_bytes = xmalloc(sizeof(unsigned char) * 8);
	ip = xmalloc(sizeof(uint32_t));

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

	/* Read ip */
	ip_string = strtok(NULL, " \t");
	read_ip(ip_string, ip);

	addStaticLease(arg, mac_bytes, ip);

	if (ENABLE_FEATURE_UDHCP_DEBUG) printStaticLeases(arg);

	return 1;
}


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

static const struct config_keyword keywords[] = {
	/* keyword       handler   variable address               default */
	{"start",        read_ip,  &(server_config.start_ip),     "192.168.0.20"},
	{"end",          read_ip,  &(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"},
	{"remaining",    read_yn,  &(server_config.remaining),    "yes"},
	{"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),    "60"},
	{"lease_file",   read_str, &(server_config.lease_file),   LEASES_FILE},
	{"pidfile",      read_str, &(server_config.pidfile),      "/var/run/udhcpd.pid"},
	{"siaddr",       read_ip,  &(server_config.siaddr),       "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), ""},
	/* ADDME: static lease */
};
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 fp;
	unsigned i;
	time_t curr = time(0);
	unsigned long tmp_time;

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

	for (i = 0; i < server_config.max_leases; i++) {
		if (leases[i].yiaddr != 0) {

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

			if (server_config.remaining) {
				if (lease_expired(&(leases[i])))
					leases[i].expires = 0;
				else leases[i].expires -= curr;
			} /* else stick with the time we got */
			leases[i].expires = htonl(leases[i].expires);
			// FIXME: error check??
			full_write(fp, &leases[i], sizeof(leases[i]));

			/* then restore it when done */
			leases[i].expires = tmp_time;
		}
	}
	close(fp);

	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)
{
	int fp;
	unsigned i;
	struct dhcpOfferedAddr lease;

	fp = open_or_warn(file, O_RDONLY);
	if (fp < 0) {
		return;
	}

	i = 0;
	while (i < server_config.max_leases
	 && full_read(fp, &lease, sizeof(lease)) == sizeof(lease)
	) {
		/* ADDME: is it a static lease */
		uint32_t y = ntohl(lease.yiaddr);
		if (y >= server_config.start_ip && y <= server_config.end_ip) {
			lease.expires = ntohl(lease.expires);
			if (!server_config.remaining)
				lease.expires -= time(NULL);
			if (!(add_lease(lease.chaddr, lease.yiaddr, lease.expires))) {
				bb_error_msg("too many leases while loading %s", file);
				break;
			}
			i++;
		}
	}
	DEBUG("Read %d leases", i);
	close(fp);
}