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
7#include <netinet/ether.h>
8
9#include "common.h"
10#include "dhcpd.h"
11#include "options.h"
12
13
14/* on these functions, make sure your datatype matches */
15static int read_ip(const char *line, void *arg)
16{
17	len_and_sockaddr *lsa;
18
19	lsa = host_and_af2sockaddr(line, 0, AF_INET);
20	if (!lsa)
21		return 0;
22	*(uint32_t*)arg = lsa->sin.sin_addr.s_addr;
23	free(lsa);
24	return 1;
25}
26
27static int read_mac(const char *line, void *arg)
28{
29	uint8_t *mac_bytes = arg;
30	struct ether_addr *temp_ether_addr;
31
32	temp_ether_addr = ether_aton(line);
33	if (temp_ether_addr == NULL)
34		return 0;
35	memcpy(mac_bytes, temp_ether_addr, 6);
36	return 1;
37}
38
39
40static int read_str(const char *line, void *arg)
41{
42	char **dest = arg;
43
44	free(*dest);
45	*dest = xstrdup(line);
46	return 1;
47}
48
49
50static int read_u32(const char *line, void *arg)
51{
52	*(uint32_t*)arg = bb_strtou32(line, NULL, 10);
53	return errno == 0;
54}
55
56
57static int read_yn(const char *line, void *arg)
58{
59	char *dest = arg;
60
61	if (!strcasecmp("yes", line)) {
62		*dest = 1;
63		return 1;
64	}
65	if (!strcasecmp("no", line)) {
66		*dest = 0;
67		return 1;
68	}
69	return 0;
70}
71
72
73/* find option 'code' in opt_list */
74struct option_set *find_option(struct option_set *opt_list, char code)
75{
76	while (opt_list && opt_list->data[OPT_CODE] < code)
77		opt_list = opt_list->next;
78
79	if (opt_list && opt_list->data[OPT_CODE] == code)
80		return opt_list;
81	return NULL;
82}
83
84
85/* add an option to the opt_list */
86static void attach_option(struct option_set **opt_list,
87		const struct dhcp_option *option, char *buffer, int length)
88{
89	struct option_set *existing, *new, **curr;
90
91	existing = find_option(*opt_list, option->code);
92	if (!existing) {
93		DEBUG("Attaching option %s to list", option->name);
94
95#if ENABLE_FEATURE_RFC3397
96		if ((option->flags & TYPE_MASK) == OPTION_STR1035)
97			/* reuse buffer and length for RFC1035-formatted string */
98			buffer = dname_enc(NULL, 0, buffer, &length);
99#endif
100
101		/* make a new option */
102		new = xmalloc(sizeof(*new));
103		new->data = xmalloc(length + 2);
104		new->data[OPT_CODE] = option->code;
105		new->data[OPT_LEN] = length;
106		memcpy(new->data + 2, buffer, length);
107
108		curr = opt_list;
109		while (*curr && (*curr)->data[OPT_CODE] < option->code)
110			curr = &(*curr)->next;
111
112		new->next = *curr;
113		*curr = new;
114#if ENABLE_FEATURE_RFC3397
115		if ((option->flags & TYPE_MASK) == OPTION_STR1035 && buffer != NULL)
116			free(buffer);
117#endif
118		return;
119	}
120
121	/* add it to an existing option */
122	DEBUG("Attaching option %s to existing member of list", option->name);
123	if (option->flags & OPTION_LIST) {
124#if ENABLE_FEATURE_RFC3397
125		if ((option->flags & TYPE_MASK) == OPTION_STR1035)
126			/* reuse buffer and length for RFC1035-formatted string */
127			buffer = dname_enc(existing->data + 2,
128					existing->data[OPT_LEN], buffer, &length);
129#endif
130		if (existing->data[OPT_LEN] + length <= 255) {
131			existing->data = xrealloc(existing->data,
132					existing->data[OPT_LEN] + length + 3);
133			if ((option->flags & TYPE_MASK) == OPTION_STRING) {
134				/* ' ' can bring us to 256 - bad */
135				if (existing->data[OPT_LEN] + length >= 255)
136					return;
137				/* add space separator between STRING options in a list */
138				existing->data[existing->data[OPT_LEN] + 2] = ' ';
139				existing->data[OPT_LEN]++;
140			}
141			memcpy(existing->data + existing->data[OPT_LEN] + 2, buffer, length);
142			existing->data[OPT_LEN] += length;
143		} /* else, ignore the data, we could put this in a second option in the future */
144#if ENABLE_FEATURE_RFC3397
145		if ((option->flags & TYPE_MASK) == OPTION_STR1035 && buffer != NULL)
146			free(buffer);
147#endif
148	} /* else, ignore the new data */
149}
150
151
152/* read a dhcp option and add it to opt_list */
153static int read_opt(const char *const_line, void *arg)
154{
155	struct option_set **opt_list = arg;
156	char *opt, *val, *endptr;
157	const struct dhcp_option *option;
158	int retval = 0, length;
159	char buffer[8];
160	char *line;
161	uint16_t *result_u16 = (uint16_t *) buffer;
162	uint32_t *result_u32 = (uint32_t *) buffer;
163
164	/* Cheat, the only const line we'll actually get is "" */
165	line = (char *) const_line;
166	opt = strtok(line, " \t=");
167	if (!opt) return 0;
168
169	option = dhcp_options;
170	while (1) {
171		if (!option->code)
172			return 0;
173		if (!strcasecmp(option->name, opt))
174			break;
175		option++;
176	}
177
178	do {
179		val = strtok(NULL, ", \t");
180		if (!val) break;
181		length = option_lengths[option->flags & TYPE_MASK];
182		retval = 0;
183		opt = buffer; /* new meaning for variable opt */
184		switch (option->flags & TYPE_MASK) {
185		case OPTION_IP:
186			retval = read_ip(val, buffer);
187			break;
188		case OPTION_IP_PAIR:
189			retval = read_ip(val, buffer);
190			val = strtok(NULL, ", \t/-");
191			if (!val)
192				retval = 0;
193			if (retval)
194				retval = read_ip(val, buffer + 4);
195			break;
196		case OPTION_STRING:
197#if ENABLE_FEATURE_RFC3397
198		case OPTION_STR1035:
199#endif
200			length = strlen(val);
201			if (length > 0) {
202				if (length > 254) length = 254;
203				opt = val;
204				retval = 1;
205			}
206			break;
207		case OPTION_BOOLEAN:
208			retval = read_yn(val, buffer);
209			break;
210		case OPTION_U8:
211			buffer[0] = strtoul(val, &endptr, 0);
212			retval = (endptr[0] == '\0');
213			break;
214		/* htonX are macros in older libc's, using temp var
215		 * in code below for safety */
216		/* TODO: use bb_strtoX? */
217		case OPTION_U16: {
218			unsigned long tmp = strtoul(val, &endptr, 0);
219			*result_u16 = htons(tmp);
220			retval = (endptr[0] == '\0' /*&& tmp < 0x10000*/);
221			break;
222		}
223		case OPTION_S16: {
224			long tmp = strtol(val, &endptr, 0);
225			*result_u16 = htons(tmp);
226			retval = (endptr[0] == '\0');
227			break;
228		}
229		case OPTION_U32: {
230			unsigned long tmp = strtoul(val, &endptr, 0);
231			*result_u32 = htonl(tmp);
232			retval = (endptr[0] == '\0');
233			break;
234		}
235		case OPTION_S32: {
236			long tmp = strtol(val, &endptr, 0);
237			*result_u32 = htonl(tmp);
238			retval = (endptr[0] == '\0');
239			break;
240		}
241		default:
242			break;
243		}
244		if (retval)
245			attach_option(opt_list, option, opt, length);
246	} while (retval && option->flags & OPTION_LIST);
247	return retval;
248}
249
250static int read_staticlease(const char *const_line, void *arg)
251{
252	char *line;
253	char *mac_string;
254	char *ip_string;
255	uint8_t *mac_bytes;
256	uint32_t *ip;
257
258	/* Allocate memory for addresses */
259	mac_bytes = xmalloc(sizeof(unsigned char) * 8);
260	ip = xmalloc(sizeof(uint32_t));
261
262	/* Read mac */
263	line = (char *) const_line;
264	mac_string = strtok(line, " \t");
265	read_mac(mac_string, mac_bytes);
266
267	/* Read ip */
268	ip_string = strtok(NULL, " \t");
269	read_ip(ip_string, ip);
270
271	addStaticLease(arg, mac_bytes, ip);
272
273	if (ENABLE_FEATURE_UDHCP_DEBUG) printStaticLeases(arg);
274
275	return 1;
276}
277
278
279struct config_keyword {
280	const char *keyword;
281	int (*handler)(const char *line, void *var);
282	void *var;
283	const char *def;
284};
285
286static const struct config_keyword keywords[] = {
287	/* keyword       handler   variable address               default */
288	{"start",        read_ip,  &(server_config.start_ip),     "192.168.0.20"},
289	{"end",          read_ip,  &(server_config.end_ip),       "192.168.0.254"},
290	{"interface",    read_str, &(server_config.interface),    "eth0"},
291	{"option",       read_opt, &(server_config.options),      ""},
292	{"opt",          read_opt, &(server_config.options),      ""},
293	/* Avoid "max_leases value not sane" warning by setting default
294	 * to default_end_ip - default_start_ip + 1: */
295	{"max_leases",   read_u32, &(server_config.max_leases),   "235"},
296	{"remaining",    read_yn,  &(server_config.remaining),    "yes"},
297	{"auto_time",    read_u32, &(server_config.auto_time),    "7200"},
298	{"decline_time", read_u32, &(server_config.decline_time), "3600"},
299	{"conflict_time",read_u32, &(server_config.conflict_time),"3600"},
300	{"offer_time",   read_u32, &(server_config.offer_time),   "60"},
301	{"min_lease",    read_u32, &(server_config.min_lease),    "60"},
302	{"lease_file",   read_str, &(server_config.lease_file),   LEASES_FILE},
303	{"pidfile",      read_str, &(server_config.pidfile),      "/var/run/udhcpd.pid"},
304	{"notify_file",  read_str, &(server_config.notify_file),  ""},
305	{"siaddr",       read_ip,  &(server_config.siaddr),       "0.0.0.0"},
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	/* ADDME: static lease */
310};
311
312
313/*
314 * Domain names may have 254 chars, and string options can be 254
315 * chars long. However, 80 bytes will be enough for most, and won't
316 * hog up memory. If you have a special application, change it
317 */
318#define READ_CONFIG_BUF_SIZE 80
319
320int read_config(const char *file)
321{
322	FILE *in;
323	char buffer[READ_CONFIG_BUF_SIZE], *token, *line;
324	int i, lm = 0;
325
326	for (i = 0; i < ARRAY_SIZE(keywords); i++)
327		if (keywords[i].def[0])
328			keywords[i].handler(keywords[i].def, keywords[i].var);
329
330	in = fopen_or_warn(file, "r");
331	if (!in) {
332		return 0;
333	}
334
335	while (fgets(buffer, READ_CONFIG_BUF_SIZE, in)) {
336		char debug_orig[READ_CONFIG_BUF_SIZE];
337		char *p;
338
339		lm++;
340		p = strchr(buffer, '\n');
341		if (p) *p = '\0';
342		if (ENABLE_FEATURE_UDHCP_DEBUG) strcpy(debug_orig, buffer);
343		p = strchr(buffer, '#');
344		if (p) *p = '\0';
345
346		if (!(token = strtok(buffer, " \t"))) continue;
347		if (!(line = strtok(NULL, ""))) continue;
348
349		/* eat leading whitespace */
350		line = skip_whitespace(line);
351		/* eat trailing whitespace */
352		i = strlen(line) - 1;
353		while (i >= 0 && isspace(line[i]))
354			line[i--] = '\0';
355
356		for (i = 0; i < ARRAY_SIZE(keywords); i++)
357			if (!strcasecmp(token, keywords[i].keyword))
358				if (!keywords[i].handler(line, keywords[i].var)) {
359					bb_error_msg("cannot parse line %d of %s", lm, file);
360					if (ENABLE_FEATURE_UDHCP_DEBUG)
361						bb_error_msg("cannot parse '%s'", debug_orig);
362					/* reset back to the default value */
363					keywords[i].handler(keywords[i].def, keywords[i].var);
364				}
365	}
366	fclose(in);
367
368	server_config.start_ip = ntohl(server_config.start_ip);
369	server_config.end_ip = ntohl(server_config.end_ip);
370
371	return 1;
372}
373
374
375void write_leases(void)
376{
377	int fp;
378	unsigned i;
379	time_t curr = time(0);
380	unsigned long tmp_time;
381
382	fp = open3_or_warn(server_config.lease_file, O_WRONLY|O_CREAT|O_TRUNC, 0666);
383	if (fp < 0) {
384		return;
385	}
386
387	for (i = 0; i < server_config.max_leases; i++) {
388		if (leases[i].yiaddr != 0) {
389
390			/* screw with the time in the struct, for easier writing */
391			tmp_time = leases[i].expires;
392
393			if (server_config.remaining) {
394				if (lease_expired(&(leases[i])))
395					leases[i].expires = 0;
396				else leases[i].expires -= curr;
397			} /* else stick with the time we got */
398			leases[i].expires = htonl(leases[i].expires);
399			full_write(fp, &leases[i], sizeof(leases[i]));
400
401			/* then restore it when done */
402			leases[i].expires = tmp_time;
403		}
404	}
405	close(fp);
406
407	if (server_config.notify_file) {
408		char *cmd = xasprintf("%s %s", server_config.notify_file, server_config.lease_file);
409		system(cmd);
410		free(cmd);
411	}
412}
413
414
415void read_leases(const char *file)
416{
417	int fp;
418	unsigned int i = 0;
419	struct dhcpOfferedAddr lease;
420
421	fp = open_or_warn(file, O_RDONLY);
422	if (fp < 0) {
423		return;
424	}
425
426	while (i < server_config.max_leases
427	 && full_read(fp, &lease, sizeof(lease)) == sizeof(lease)
428	) {
429		/* ADDME: is it a static lease */
430		uint32_t y = ntohl(lease.yiaddr);
431		if (y >= server_config.start_ip && y <= server_config.end_ip) {
432			lease.expires = ntohl(lease.expires);
433			if (!server_config.remaining)
434				lease.expires -= time(0);
435			if (!(add_lease(lease.chaddr, lease.yiaddr, lease.expires))) {
436				bb_error_msg("too many leases while loading %s", file);
437				break;
438			}
439			i++;
440		}
441	}
442	DEBUG("Read %d leases", i);
443	close(fp);
444}
445