libxt_time.c revision d64d54777b4a9405a8229a533e44a2e80f000a9f 
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	ret = mktime(&tm);
140	if (ret >= 0)
141		return ret;
142	perror("mktime");
143	xtables_error(OTHER_PROBLEM, "mktime returned an error");
144
145 out:
146	xtables_error(PARAMETER_PROBLEM, "Invalid date \"%s\" specified. Should "
147	           "be YYYY[-MM[-DD[Thh[:mm[:ss]]]]]", os);
148	return -1;
149}
150
151static unsigned int time_parse_minutes(const char *s)
152{
153	unsigned int hour, minute, second = 0;
154	char *e;
155
156	hour = strtoul(s, &e, 10);
157	if (*e != ':' || hour > 23)
158		goto out;
159
160	s = e + 1;
161	minute = strtoul(s, &e, 10);
162	if ((*e != ':' && *e != '\0') || minute > 59)
163		goto out;
164	if (*e == '\0')
165		goto eval;
166
167	s = e + 1;
168	second = strtoul(s, &e, 10);
169	if (*e != '\0' || second > 59)
170		goto out;
171
172 eval:
173	return 60 * 60 * hour + 60 * minute + second;
174
175 out:
176	xtables_error(PARAMETER_PROBLEM, "invalid time \"%s\" specified, "
177	           "should be hh:mm[:ss] format and within the boundaries", s);
178	return -1;
179}
180
181static const char *my_strseg(char *buf, unsigned int buflen,
182    const char **arg, char delim)
183{
184	const char *sep;
185
186	if (*arg == NULL || **arg == '\0')
187		return NULL;
188	sep = strchr(*arg, delim);
189	if (sep == NULL) {
190		snprintf(buf, buflen, "%s", *arg);
191		*arg = NULL;
192		return buf;
193	}
194	snprintf(buf, buflen, "%.*s", (unsigned int)(sep - *arg), *arg);
195	*arg = sep + 1;
196	return buf;
197}
198
199static uint32_t time_parse_monthdays(const char *arg)
200{
201	char day[3], *err = NULL;
202	uint32_t ret = 0;
203	unsigned int i;
204
205	while (my_strseg(day, sizeof(day), &arg, ',') != NULL) {
206		i = strtoul(day, &err, 0);
207		if ((*err != ',' && *err != '\0') || i > 31)
208			xtables_error(PARAMETER_PROBLEM,
209			           "%s is not a valid day for --monthdays", day);
210		ret |= 1 << i;
211	}
212
213	return ret;
214}
215
216static unsigned int time_parse_weekdays(const char *arg)
217{
218	char day[4], *err = NULL;
219	unsigned int i, ret = 0;
220	bool valid;
221
222	while (my_strseg(day, sizeof(day), &arg, ',') != NULL) {
223		i = strtoul(day, &err, 0);
224		if (*err == '\0') {
225			if (i == 0)
226				xtables_error(PARAMETER_PROBLEM,
227				           "No, the week does NOT begin with Sunday.");
228			ret |= 1 << i;
229			continue;
230		}
231
232		valid = false;
233		for (i = 1; i < ARRAY_SIZE(week_days); ++i)
234			if (strncmp(day, week_days[i], 2) == 0) {
235				ret |= 1 << i;
236				valid = true;
237			}
238
239		if (!valid)
240			xtables_error(PARAMETER_PROBLEM,
241			           "%s is not a valid day specifier", day);
242	}
243
244	return ret;
245}
246
247static void time_parse(struct xt_option_call *cb)
248{
249	struct xt_time_info *info = cb->data;
250
251	xtables_option_parse(cb);
252	switch (cb->entry->id) {
253	case O_DATE_START:
254		info->date_start = time_parse_date(cb->arg, false);
255		break;
256	case O_DATE_STOP:
257		info->date_stop = time_parse_date(cb->arg, true);
258		break;
259	case O_TIME_START:
260		info->daytime_start = time_parse_minutes(cb->arg);
261		break;
262	case O_TIME_STOP:
263		info->daytime_stop = time_parse_minutes(cb->arg);
264		break;
265	case O_LOCAL_TZ:
266		info->flags |= XT_TIME_LOCAL_TZ;
267		break;
268	case O_MONTHDAYS:
269		info->monthdays_match = time_parse_monthdays(cb->arg);
270		if (cb->invert)
271			info->monthdays_match ^= XT_TIME_ALL_MONTHDAYS;
272		break;
273	case O_WEEKDAYS:
274		info->weekdays_match = time_parse_weekdays(cb->arg);
275		if (cb->invert)
276			info->weekdays_match ^= XT_TIME_ALL_WEEKDAYS;
277		break;
278	case O_UTC:
279		info->flags &= ~XT_TIME_LOCAL_TZ;
280		break;
281	}
282}
283
284static void time_print_date(time_t date, const char *command)
285{
286	struct tm *t;
287
288	/* If it is the default value, do not print it. */
289	if (date == 0 || date == LONG_MAX)
290		return;
291
292	t = localtime(&date);
293	if (command != NULL)
294		/*
295		 * Need a contiguous string (no whitespaces), hence using
296		 * the ISO 8601 "T" variant.
297		 */
298		printf(" %s %04u-%02u-%02uT%02u:%02u:%02u",
299		       command, t->tm_year + 1900, t->tm_mon + 1,
300		       t->tm_mday, t->tm_hour, t->tm_min, t->tm_sec);
301	else
302		printf(" %04u-%02u-%02u %02u:%02u:%02u",
303		       t->tm_year + 1900, t->tm_mon + 1, t->tm_mday,
304		       t->tm_hour, t->tm_min, t->tm_sec);
305}
306
307static void time_print_monthdays(uint32_t mask, bool human_readable)
308{
309	unsigned int i, nbdays = 0;
310
311	printf(" ");
312	for (i = 1; i <= 31; ++i)
313		if (mask & (1 << i)) {
314			if (nbdays++ > 0)
315				printf(",");
316			printf("%u", i);
317			if (human_readable)
318				switch (i % 10) {
319					case 1:
320						printf("st");
321						break;
322					case 2:
323						printf("nd");
324						break;
325					case 3:
326						printf("rd");
327						break;
328					default:
329						printf("th");
330						break;
331				}
332		}
333}
334
335static void time_print_weekdays(unsigned int mask)
336{
337	unsigned int i, nbdays = 0;
338
339	printf(" ");
340	for (i = 1; i <= 7; ++i)
341		if (mask & (1 << i)) {
342			if (nbdays > 0)
343				printf(",%s", week_days[i]);
344			else
345				printf("%s", week_days[i]);
346			++nbdays;
347		}
348}
349
350static inline void divide_time(unsigned int fulltime, unsigned int *hours,
351    unsigned int *minutes, unsigned int *seconds)
352{
353	*seconds  = fulltime % 60;
354	fulltime /= 60;
355	*minutes  = fulltime % 60;
356	*hours    = fulltime / 60;
357}
358
359static void time_print(const void *ip, const struct xt_entry_match *match,
360                       int numeric)
361{
362	const struct xt_time_info *info = (const void *)match->data;
363	unsigned int h, m, s;
364
365	printf(" TIME");
366
367	if (info->daytime_start != XT_TIME_MIN_DAYTIME ||
368	    info->daytime_stop != XT_TIME_MAX_DAYTIME) {
369		divide_time(info->daytime_start, &h, &m, &s);
370		printf(" from %02u:%02u:%02u", h, m, s);
371		divide_time(info->daytime_stop, &h, &m, &s);
372		printf(" to %02u:%02u:%02u", h, m, s);
373	}
374	if (info->weekdays_match != XT_TIME_ALL_WEEKDAYS) {
375		printf(" on");
376		time_print_weekdays(info->weekdays_match);
377	}
378	if (info->monthdays_match != XT_TIME_ALL_MONTHDAYS) {
379		printf(" on");
380		time_print_monthdays(info->monthdays_match, true);
381	}
382	if (info->date_start != 0) {
383		printf(" starting from");
384		time_print_date(info->date_start, NULL);
385	}
386	if (info->date_stop != INT_MAX) {
387		printf(" until date");
388		time_print_date(info->date_stop, NULL);
389	}
390	if (!(info->flags & XT_TIME_LOCAL_TZ))
391		printf(" UTC");
392}
393
394static void time_save(const void *ip, const struct xt_entry_match *match)
395{
396	const struct xt_time_info *info = (const void *)match->data;
397	unsigned int h, m, s;
398
399	if (info->daytime_start != XT_TIME_MIN_DAYTIME ||
400	    info->daytime_stop != XT_TIME_MAX_DAYTIME) {
401		divide_time(info->daytime_start, &h, &m, &s);
402		printf(" --timestart %02u:%02u:%02u", h, m, s);
403		divide_time(info->daytime_stop, &h, &m, &s);
404		printf(" --timestop %02u:%02u:%02u", h, m, s);
405	}
406	if (info->monthdays_match != XT_TIME_ALL_MONTHDAYS) {
407		printf(" --monthdays");
408		time_print_monthdays(info->monthdays_match, false);
409	}
410	if (info->weekdays_match != XT_TIME_ALL_WEEKDAYS) {
411		printf(" --weekdays");
412		time_print_weekdays(info->weekdays_match);
413	}
414	time_print_date(info->date_start, "--datestart");
415	time_print_date(info->date_stop, "--datestop");
416	if (!(info->flags & XT_TIME_LOCAL_TZ))
417		printf(" --utc");
418}
419
420static struct xtables_match time_match = {
421	.name          = "time",
422	.family        = NFPROTO_UNSPEC,
423	.version       = XTABLES_VERSION,
424	.size          = XT_ALIGN(sizeof(struct xt_time_info)),
425	.userspacesize = XT_ALIGN(sizeof(struct xt_time_info)),
426	.help          = time_help,
427	.init          = time_init,
428	.print         = time_print,
429	.save          = time_save,
430	.x6_parse      = time_parse,
431	.x6_options    = time_opts,
432};
433
434void _init(void)
435{
436	xtables_register_match(&time_match);
437}
438