libxt_time.c revision b1319cc083de658c0007da93f25d19874f75d55f 
1/*
2 *	libxt_time - iptables part for xt_time
3 *	Copyright © CC Computer Consultants GmbH, 2007
4 *	Contact: <jengelh@computergmbh.de>
5 *
6 *	libxt_time.c is free software; you can redistribute it and/or modify
7 *	it under the terms of the GNU General Public License as published by
8 *	the Free Software Foundation; either version 2 or 3 of the License.
9 *
10 *	Based on libipt_time.c.
11 */
12#include <stdio.h>
13#include <string.h>
14#include <stdlib.h>
15#include <time.h>
16#include <linux/types.h>
17#include <linux/netfilter/xt_time.h>
18#include <xtables.h>
19
20enum {
21	O_DATE_START = 0,
22	O_DATE_STOP,
23	O_TIME_START,
24	O_TIME_STOP,
25	O_MONTHDAYS,
26	O_WEEKDAYS,
27	O_LOCAL_TZ,
28	O_UTC,
29};
30
31static const char *const week_days[] = {
32	NULL, "Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun",
33};
34
35static const struct xt_option_entry time_opts[] = {
36	{.name = "datestart", .id = O_DATE_START, .type = XTTYPE_STRING},
37	{.name = "datestop", .id = O_DATE_STOP, .type = XTTYPE_STRING},
38	{.name = "timestart", .id = O_TIME_START, .type = XTTYPE_STRING},
39	{.name = "timestop", .id = O_TIME_STOP, .type = XTTYPE_STRING},
40	{.name = "weekdays", .id = O_WEEKDAYS, .type = XTTYPE_STRING,
41	 .flags = XTOPT_INVERT},
42	{.name = "monthdays", .id = O_MONTHDAYS, .type = XTTYPE_STRING,
43	 .flags = XTOPT_INVERT},
44	{.name = "localtz", .id = O_LOCAL_TZ, .type = XTTYPE_NONE},
45	{.name = "utc", .id = O_UTC, .type = XTTYPE_NONE},
46	XTOPT_TABLEEND,
47};
48
49static void time_help(void)
50{
51	printf(
52"time match options:\n"
53"    --datestart time     Start and stop time, to be given in ISO 8601\n"
54"    --datestop time      (YYYY[-MM[-DD[Thh[:mm[:ss]]]]])\n"
55"    --timestart time     Start and stop daytime (hh:mm[:ss])\n"
56"    --timestop time      (between 00:00:00 and 23:59:59)\n"
57"[!] --monthdays value    List of days on which to match, separated by comma\n"
58"                         (Possible days: 1 to 31; defaults to all)\n"
59"[!] --weekdays value     List of weekdays on which to match, sep. by comma\n"
60"                         (Possible days: Mon,Tue,Wed,Thu,Fri,Sat,Sun or 1 to 7\n"
61"                         Defaults to all weekdays.)\n"
62"    --localtz/--utc      Time is interpreted as UTC/local time\n");
63}
64
65static void time_init(struct xt_entry_match *m)
66{
67	struct xt_time_info *info = (void *)m->data;
68
69	/* By default, we match on every day, every daytime */
70	info->monthdays_match = XT_TIME_ALL_MONTHDAYS;
71	info->weekdays_match  = XT_TIME_ALL_WEEKDAYS;
72	info->daytime_start   = XT_TIME_MIN_DAYTIME;
73	info->daytime_stop    = XT_TIME_MAX_DAYTIME;
74
75	/* ...and have no date-begin or date-end boundary */
76	info->date_start = 0;
77	info->date_stop  = INT_MAX;
78
79	/* local time is default */
80	info->flags |= XT_TIME_LOCAL_TZ;
81}
82
83static time_t time_parse_date(const char *s, bool end)
84{
85	unsigned int month = 1, day = 1, hour = 0, minute = 0, second = 0;
86	unsigned int year  = end ? 2038 : 1970;
87	const char *os = s;
88	struct tm tm;
89	time_t ret;
90	char *e;
91
92	year = strtoul(s, &e, 10);
93	if ((*e != '-' && *e != '\0') || year < 1970 || year > 2038)
94		goto out;
95	if (*e == '\0')
96		goto eval;
97
98	s = e + 1;
99	month = strtoul(s, &e, 10);
100	if ((*e != '-' && *e != '\0') || month > 12)
101		goto out;
102	if (*e == '\0')
103		goto eval;
104
105	s = e + 1;
106	day = strtoul(s, &e, 10);
107	if ((*e != 'T' && *e != '\0') || day > 31)
108		goto out;
109	if (*e == '\0')
110		goto eval;
111
112	s = e + 1;
113	hour = strtoul(s, &e, 10);
114	if ((*e != ':' && *e != '\0') || hour > 23)
115		goto out;
116	if (*e == '\0')
117		goto eval;
118
119	s = e + 1;
120	minute = strtoul(s, &e, 10);
121	if ((*e != ':' && *e != '\0') || minute > 59)
122		goto out;
123	if (*e == '\0')
124		goto eval;
125
126	s = e + 1;
127	second = strtoul(s, &e, 10);
128	if (*e != '\0' || second > 59)
129		goto out;
130
131 eval:
132	tm.tm_year = year - 1900;
133	tm.tm_mon  = month - 1;
134	tm.tm_mday = day;
135	tm.tm_hour = hour;
136	tm.tm_min  = minute;
137	tm.tm_sec  = second;
138	tm.tm_isdst = 0;
139	/*
140	 * Offsetting, if any, is done by xt_time.ko,
141	 * so we have to disable it here in userspace.
142	 */
143	setenv("TZ", "UTC", true);
144	tzset();
145	ret = mktime(&tm);
146	if (ret >= 0)
147		return ret;
148	perror("mktime");
149	xtables_error(OTHER_PROBLEM, "mktime returned an error");
150
151 out:
152	xtables_error(PARAMETER_PROBLEM, "Invalid date \"%s\" specified. Should "
153	           "be YYYY[-MM[-DD[Thh[:mm[:ss]]]]]", os);
154	return -1;
155}
156
157static unsigned int time_parse_minutes(const char *s)
158{
159	unsigned int hour, minute, second = 0;
160	char *e;
161
162	hour = strtoul(s, &e, 10);
163	if (*e != ':' || hour > 23)
164		goto out;
165
166	s = e + 1;
167	minute = strtoul(s, &e, 10);
168	if ((*e != ':' && *e != '\0') || minute > 59)
169		goto out;
170	if (*e == '\0')
171		goto eval;
172
173	s = e + 1;
174	second = strtoul(s, &e, 10);
175	if (*e != '\0' || second > 59)
176		goto out;
177
178 eval:
179	return 60 * 60 * hour + 60 * minute + second;
180
181 out:
182	xtables_error(PARAMETER_PROBLEM, "invalid time \"%s\" specified, "
183	           "should be hh:mm[:ss] format and within the boundaries", s);
184	return -1;
185}
186
187static const char *my_strseg(char *buf, unsigned int buflen,
188    const char **arg, char delim)
189{
190	const char *sep;
191
192	if (*arg == NULL || **arg == '\0')
193		return NULL;
194	sep = strchr(*arg, delim);
195	if (sep == NULL) {
196		snprintf(buf, buflen, "%s", *arg);
197		*arg = NULL;
198		return buf;
199	}
200	snprintf(buf, buflen, "%.*s", (unsigned int)(sep - *arg), *arg);
201	*arg = sep + 1;
202	return buf;
203}
204
205static uint32_t time_parse_monthdays(const char *arg)
206{
207	char day[3], *err = NULL;
208	uint32_t ret = 0;
209	unsigned int i;
210
211	while (my_strseg(day, sizeof(day), &arg, ',') != NULL) {
212		i = strtoul(day, &err, 0);
213		if ((*err != ',' && *err != '\0') || i > 31)
214			xtables_error(PARAMETER_PROBLEM,
215			           "%s is not a valid day for --monthdays", day);
216		ret |= 1 << i;
217	}
218
219	return ret;
220}
221
222static unsigned int time_parse_weekdays(const char *arg)
223{
224	char day[4], *err = NULL;
225	unsigned int i, ret = 0;
226	bool valid;
227
228	while (my_strseg(day, sizeof(day), &arg, ',') != NULL) {
229		i = strtoul(day, &err, 0);
230		if (*err == '\0') {
231			if (i == 0)
232				xtables_error(PARAMETER_PROBLEM,
233				           "No, the week does NOT begin with Sunday.");
234			ret |= 1 << i;
235			continue;
236		}
237
238		valid = false;
239		for (i = 1; i < ARRAY_SIZE(week_days); ++i)
240			if (strncmp(day, week_days[i], 2) == 0) {
241				ret |= 1 << i;
242				valid = true;
243			}
244
245		if (!valid)
246			xtables_error(PARAMETER_PROBLEM,
247			           "%s is not a valid day specifier", day);
248	}
249
250	return ret;
251}
252
253static void time_parse(struct xt_option_call *cb)
254{
255	struct xt_time_info *info = cb->data;
256
257	xtables_option_parse(cb);
258	switch (cb->entry->id) {
259	case O_DATE_START:
260		info->date_start = time_parse_date(cb->arg, false);
261		break;
262	case O_DATE_STOP:
263		info->date_stop = time_parse_date(cb->arg, true);
264		break;
265	case O_TIME_START:
266		info->daytime_start = time_parse_minutes(cb->arg);
267		break;
268	case O_TIME_STOP:
269		info->daytime_stop = time_parse_minutes(cb->arg);
270		break;
271	case O_LOCAL_TZ:
272		info->flags |= XT_TIME_LOCAL_TZ;
273		break;
274	case O_MONTHDAYS:
275		info->monthdays_match = time_parse_monthdays(cb->arg);
276		if (cb->invert)
277			info->monthdays_match ^= XT_TIME_ALL_MONTHDAYS;
278		break;
279	case O_WEEKDAYS:
280		info->weekdays_match = time_parse_weekdays(cb->arg);
281		if (cb->invert)
282			info->weekdays_match ^= XT_TIME_ALL_WEEKDAYS;
283		break;
284	case O_UTC:
285		info->flags &= ~XT_TIME_LOCAL_TZ;
286		break;
287	}
288}
289
290static void time_print_date(time_t date, const char *command)
291{
292	struct tm *t;
293
294	/* If it is the default value, do not print it. */
295	if (date == 0 || date == LONG_MAX)
296		return;
297
298	t = gmtime(&date);
299	if (command != NULL)
300		/*
301		 * Need a contiguous string (no whitespaces), hence using
302		 * the ISO 8601 "T" variant.
303		 */
304		printf(" %s %04u-%02u-%02uT%02u:%02u:%02u",
305		       command, t->tm_year + 1900, t->tm_mon + 1,
306		       t->tm_mday, t->tm_hour, t->tm_min, t->tm_sec);
307	else
308		printf(" %04u-%02u-%02u %02u:%02u:%02u",
309		       t->tm_year + 1900, t->tm_mon + 1, t->tm_mday,
310		       t->tm_hour, t->tm_min, t->tm_sec);
311}
312
313static void time_print_monthdays(uint32_t mask, bool human_readable)
314{
315	unsigned int i, nbdays = 0;
316
317	printf(" ");
318	for (i = 1; i <= 31; ++i)
319		if (mask & (1 << i)) {
320			if (nbdays++ > 0)
321				printf(",");
322			printf("%u", i);
323			if (human_readable)
324				switch (i % 10) {
325					case 1:
326						printf("st");
327						break;
328					case 2:
329						printf("nd");
330						break;
331					case 3:
332						printf("rd");
333						break;
334					default:
335						printf("th");
336						break;
337				}
338		}
339}
340
341static void time_print_weekdays(unsigned int mask)
342{
343	unsigned int i, nbdays = 0;
344
345	printf(" ");
346	for (i = 1; i <= 7; ++i)
347		if (mask & (1 << i)) {
348			if (nbdays > 0)
349				printf(",%s", week_days[i]);
350			else
351				printf("%s", week_days[i]);
352			++nbdays;
353		}
354}
355
356static inline void divide_time(unsigned int fulltime, unsigned int *hours,
357    unsigned int *minutes, unsigned int *seconds)
358{
359	*seconds  = fulltime % 60;
360	fulltime /= 60;
361	*minutes  = fulltime % 60;
362	*hours    = fulltime / 60;
363}
364
365static void time_print(const void *ip, const struct xt_entry_match *match,
366                       int numeric)
367{
368	const struct xt_time_info *info = (const void *)match->data;
369	unsigned int h, m, s;
370
371	printf(" TIME");
372
373	if (info->daytime_start != XT_TIME_MIN_DAYTIME ||
374	    info->daytime_stop != XT_TIME_MAX_DAYTIME) {
375		divide_time(info->daytime_start, &h, &m, &s);
376		printf(" from %02u:%02u:%02u", h, m, s);
377		divide_time(info->daytime_stop, &h, &m, &s);
378		printf(" to %02u:%02u:%02u", h, m, s);
379	}
380	if (info->weekdays_match != XT_TIME_ALL_WEEKDAYS) {
381		printf(" on");
382		time_print_weekdays(info->weekdays_match);
383	}
384	if (info->monthdays_match != XT_TIME_ALL_MONTHDAYS) {
385		printf(" on");
386		time_print_monthdays(info->monthdays_match, true);
387	}
388	if (info->date_start != 0) {
389		printf(" starting from");
390		time_print_date(info->date_start, NULL);
391	}
392	if (info->date_stop != INT_MAX) {
393		printf(" until date");
394		time_print_date(info->date_stop, NULL);
395	}
396	if (!(info->flags & XT_TIME_LOCAL_TZ))
397		printf(" UTC");
398}
399
400static void time_save(const void *ip, const struct xt_entry_match *match)
401{
402	const struct xt_time_info *info = (const void *)match->data;
403	unsigned int h, m, s;
404
405	if (info->daytime_start != XT_TIME_MIN_DAYTIME ||
406	    info->daytime_stop != XT_TIME_MAX_DAYTIME) {
407		divide_time(info->daytime_start, &h, &m, &s);
408		printf(" --timestart %02u:%02u:%02u", h, m, s);
409		divide_time(info->daytime_stop, &h, &m, &s);
410		printf(" --timestop %02u:%02u:%02u", h, m, s);
411	}
412	if (info->monthdays_match != XT_TIME_ALL_MONTHDAYS) {
413		printf(" --monthdays");
414		time_print_monthdays(info->monthdays_match, false);
415	}
416	if (info->weekdays_match != XT_TIME_ALL_WEEKDAYS) {
417		printf(" --weekdays");
418		time_print_weekdays(info->weekdays_match);
419	}
420	time_print_date(info->date_start, "--datestart");
421	time_print_date(info->date_stop, "--datestop");
422	if (!(info->flags & XT_TIME_LOCAL_TZ))
423		printf(" --utc");
424}
425
426static struct xtables_match time_match = {
427	.name          = "time",
428	.family        = NFPROTO_UNSPEC,
429	.version       = XTABLES_VERSION,
430	.size          = XT_ALIGN(sizeof(struct xt_time_info)),
431	.userspacesize = XT_ALIGN(sizeof(struct xt_time_info)),
432	.help          = time_help,
433	.init          = time_init,
434	.print         = time_print,
435	.save          = time_save,
436	.x6_parse      = time_parse,
437	.x6_options    = time_opts,
438};
439
440void _init(void)
441{
442	xtables_register_match(&time_match);
443}
444