libxt_time.c revision 23545c2a7a31c68c1e49c7c901b632c2f1c59968 
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 <sys/types.h>
13#include <getopt.h>
14#include <stdbool.h>
15#include <stdio.h>
16#include <string.h>
17#include <stdlib.h>
18#include <stddef.h>
19#include <time.h>
20#include <linux/netfilter/xt_time.h>
21#include <xtables.h>
22#define ARRAY_SIZE(x) (sizeof(x) / sizeof(*x))
23
24enum { /* getopt "seen" bits */
25	F_DATE_START = 1 << 0,
26	F_DATE_STOP  = 1 << 1,
27	F_TIME_START = 1 << 2,
28	F_TIME_STOP  = 1 << 3,
29	F_MONTHDAYS  = 1 << 4,
30	F_WEEKDAYS   = 1 << 5,
31	F_TIMEZONE   = 1 << 6,
32};
33
34static const char *const week_days[] = {
35	NULL, "Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun",
36};
37
38static const struct option time_opts[] = {
39	{"datestart", true,  NULL, 'D'},
40	{"datestop",  true,  NULL, 'E'},
41	{"timestart", true,  NULL, 'X'},
42	{"timestop",  true,  NULL, 'Y'},
43	{"weekdays",  true,  NULL, 'w'},
44	{"monthdays", true,  NULL, 'm'},
45	{"localtz",   false, NULL, 'l'},
46	{"utc",       false, NULL, 'u'},
47	{ .name = NULL }
48};
49
50static void time_help(void)
51{
52	printf(
53"TIME v%s options:\n"
54"  --datestart time     Start and stop time, to be given in ISO 8601\n"
55"  --datestop time      (YYYY[-MM[-DD[Thh[:mm[:ss]]]]])\n"
56"  --timestart time     Start and stop daytime (hh:mm[:ss])\n"
57"  --timestop time      (between 00:00:00 and 23:59:59)\n"
58"  --monthdays value    List of days on which to match, separated by comma\n"
59"                       (Possible days: 1 to 31; defaults to all)\n"
60"  --weekdays value     List of weekdays on which to match, sep. by comma\n"
61"                       (Possible days: Mon,Tue,Wed,Thu,Fri,Sat,Sun or 1 to 7\n"
62"                       Defaults to all weekdays.)\n"
63"  --localtz/--utc      Time is interpreted as UTC/local time\n",
64IPTABLES_VERSION);
65}
66
67static void time_init(struct xt_entry_match *m)
68{
69	struct xt_time_info *info = (void *)m->data;
70
71	/* By default, we match on every day, every daytime */
72	info->monthdays_match = XT_TIME_ALL_MONTHDAYS;
73	info->weekdays_match  = XT_TIME_ALL_WEEKDAYS;
74	info->daytime_start   = XT_TIME_MIN_DAYTIME;
75	info->daytime_stop    = XT_TIME_MAX_DAYTIME;
76
77	/* ...and have no date-begin or date-end boundary */
78	info->date_start = 0;
79	info->date_stop  = INT_MAX;
80
81	/* local time is default */
82	info->flags |= XT_TIME_LOCAL_TZ;
83}
84
85static time_t time_parse_date(const char *s, bool end)
86{
87	unsigned int month = 1, day = 1, hour = 0, minute = 0, second = 0;
88	unsigned int year  = end ? 2038 : 1970;
89	const char *os = s;
90	struct tm tm;
91	time_t ret;
92	char *e;
93
94	year = strtoul(s, &e, 10);
95	if ((*e != '-' && *e != '\0') || year < 1970 || year > 2038)
96		goto out;
97	if (*e == '\0')
98		goto eval;
99
100	s = e + 1;
101	month = strtoul(s, &e, 10);
102	if ((*e != '-' && *e != '\0') || month > 12)
103		goto out;
104	if (*e == '\0')
105		goto eval;
106
107	s = e + 1;
108	day = strtoul(s, &e, 10);
109	if ((*e != 'T' && *e != '\0') || day > 31)
110		goto out;
111	if (*e == '\0')
112		goto eval;
113
114	s = e + 1;
115	hour = strtoul(s, &e, 10);
116	if ((*e != ':' && *e != '\0') || hour > 23)
117		goto out;
118	if (*e == '\0')
119		goto eval;
120
121	s = e + 1;
122	minute = strtoul(s, &e, 10);
123	if ((*e != ':' && *e != '\0') || minute > 59)
124		goto out;
125	if (*e == '\0')
126		goto eval;
127
128	s = e + 1;
129	second = strtoul(s, &e, 10);
130	if (*e != '\0' || second > 59)
131		goto out;
132
133 eval:
134	tm.tm_year = year - 1900;
135	tm.tm_mon  = month - 1;
136	tm.tm_mday = day;
137	tm.tm_hour = hour;
138	tm.tm_min  = minute;
139	tm.tm_sec  = second;
140	ret = mktime(&tm);
141	if (ret >= 0)
142		return ret;
143	perror("mktime");
144	exit_error(OTHER_PROBLEM, "mktime returned an error");
145
146 out:
147	exit_error(PARAMETER_PROBLEM, "Invalid date \"%s\" specified. Should "
148	           "be YYYY[-MM[-DD[Thh[:mm[:ss]]]]]", os);
149	return -1;
150}
151
152static unsigned int time_parse_minutes(const char *s)
153{
154	unsigned int hour, minute, second = 0;
155	char *e;
156
157	hour = strtoul(s, &e, 10);
158	if (*e != ':' || hour > 23)
159		goto out;
160
161	s = e + 1;
162	minute = strtoul(s, &e, 10);
163	if ((*e != ':' && *e != '\0') || minute > 59)
164		goto out;
165	if (*e == '\0')
166		goto eval;
167
168	s = e + 1;
169	second = strtoul(s, &e, 10);
170	if (*e != '\0' || second > 59)
171		goto out;
172
173 eval:
174	return 60 * 60 * hour + 60 * minute + second;
175
176 out:
177	exit_error(PARAMETER_PROBLEM, "invalid time \"%s\" specified, "
178	           "should be hh:mm[:ss] format and within the boundaries", s);
179	return -1;
180}
181
182static const char *my_strseg(char *buf, unsigned int buflen,
183    const char **arg, char delim)
184{
185	const char *sep;
186
187	if (*arg == NULL || **arg == '\0')
188		return NULL;
189	sep = strchr(*arg, delim);
190	if (sep == NULL) {
191		snprintf(buf, buflen, "%s", *arg);
192		*arg = NULL;
193		return buf;
194	}
195	snprintf(buf, buflen, "%.*s", (unsigned int)(sep - *arg), *arg);
196	*arg = sep + 1;
197	return buf;
198}
199
200static uint32_t time_parse_monthdays(const char *arg)
201{
202	char day[3], *err = NULL;
203	uint32_t ret = 0;
204	unsigned int i;
205
206	while (my_strseg(day, sizeof(day), &arg, ',') != NULL) {
207		i = strtoul(day, &err, 0);
208		if ((*err != ',' && *err != '\0') || i > 31)
209			exit_error(PARAMETER_PROBLEM,
210			           "%s is not a valid day for --monthdays", day);
211		ret |= 1 << i;
212	}
213
214	return ret;
215}
216
217static unsigned int time_parse_weekdays(const char *arg)
218{
219	char day[4], *err = NULL;
220	unsigned int i, ret = 0;
221	bool valid;
222
223	while (my_strseg(day, sizeof(day), &arg, ',') != NULL) {
224		i = strtoul(day, &err, 0);
225		if (*err == '\0') {
226			if (i == 0)
227				exit_error(PARAMETER_PROBLEM,
228				           "No, the week does NOT begin with Sunday.");
229			ret |= 1 << i;
230			continue;
231		}
232
233		valid = false;
234		for (i = 1; i < ARRAY_SIZE(week_days); ++i)
235			if (strncmp(day, week_days[i], 2) == 0) {
236				ret |= 1 << i;
237				valid = true;
238			}
239
240		if (!valid)
241			exit_error(PARAMETER_PROBLEM,
242			           "%s is not a valid day specifier", day);
243	}
244
245	return ret;
246}
247
248static int time_parse(int c, char **argv, int invert, unsigned int *flags,
249                      const void *entry, struct xt_entry_match **match)
250{
251	struct xt_time_info *info = (void *)(*match)->data;
252
253	switch (c) {
254	case 'D': /* --datestart */
255		if (*flags & F_DATE_START)
256			exit_error(PARAMETER_PROBLEM,
257			           "Cannot specify --datestart twice");
258		if (invert)
259			exit_error(PARAMETER_PROBLEM,
260			           "Unexpected \"!\" with --datestart");
261		info->date_start = time_parse_date(optarg, false);
262		*flags |= F_DATE_START;
263		return 1;
264	case 'E': /* --datestop */
265		if (*flags & F_DATE_STOP)
266			exit_error(PARAMETER_PROBLEM,
267			           "Cannot specify --datestop more than once");
268		if (invert)
269			exit_error(PARAMETER_PROBLEM,
270			           "unexpected \"!\" with --datestop");
271		info->date_stop = time_parse_date(optarg, true);
272		*flags |= F_DATE_STOP;
273		return 1;
274	case 'X': /* --timestart */
275		if (*flags & F_TIME_START)
276			exit_error(PARAMETER_PROBLEM,
277			           "Cannot specify --timestart more than once");
278		if (invert)
279			exit_error(PARAMETER_PROBLEM,
280			           "Unexpected \"!\" with --timestart");
281		info->daytime_start = time_parse_minutes(optarg);
282		*flags |= F_TIME_START;
283		return 1;
284	case 'Y': /* --timestop */
285		if (*flags & F_TIME_STOP)
286			exit_error(PARAMETER_PROBLEM,
287			           "Cannot specify --timestop more than once");
288		if (invert)
289			exit_error(PARAMETER_PROBLEM,
290			           "Unexpected \"!\" with --timestop");
291		info->daytime_stop = time_parse_minutes(optarg);
292		*flags |= F_TIME_STOP;
293		return 1;
294	case 'l': /* --localtz */
295		if (*flags & F_TIMEZONE)
296			exit_error(PARAMETER_PROBLEM,
297			           "Can only specify exactly one of --localtz or --utc");
298		info->flags |= XT_TIME_LOCAL_TZ;
299		*flags |= F_TIMEZONE;
300		return 1;
301	case 'm': /* --monthdays */
302		if (*flags & F_MONTHDAYS)
303			exit_error(PARAMETER_PROBLEM,
304			           "Cannot specify --monthdays more than once");
305		info->monthdays_match = time_parse_monthdays(optarg);
306		if (invert)
307			info->monthdays_match ^= XT_TIME_ALL_MONTHDAYS;
308		*flags |= F_MONTHDAYS;
309		return 1;
310	case 'w': /* --weekdays */
311		if (*flags & F_WEEKDAYS)
312			exit_error(PARAMETER_PROBLEM,
313			           "Cannot specify --weekdays more than once");
314		info->weekdays_match = time_parse_weekdays(optarg);
315		if (invert)
316			info->weekdays_match ^= XT_TIME_ALL_WEEKDAYS;
317		*flags |= F_WEEKDAYS;
318		return 1;
319	case 'u': /* --utc */
320		if (*flags & F_TIMEZONE)
321			exit_error(PARAMETER_PROBLEM,
322			           "Can only specify exactly one of --localtz or --utc");
323		info->flags &= ~XT_TIME_LOCAL_TZ;
324		*flags |= F_TIMEZONE;
325		return 1;
326	}
327	return 0;
328}
329
330static void time_print_date(time_t date, const char *command)
331{
332	struct tm *t;
333
334	/* If it is the default value, do not print it. */
335	if (date == 0 || date == LONG_MAX)
336		return;
337
338	t = localtime(&date);
339	if (command != NULL)
340		/*
341		 * Need a contiguous string (no whitespaces), hence using
342		 * the ISO 8601 "T" variant.
343		 */
344		printf("%s %04u-%02u-%02uT%02u:%02u:%02u ",
345		       command, t->tm_year + 1900, t->tm_mon + 1,
346		       t->tm_mday, t->tm_hour, t->tm_min, t->tm_sec);
347	else
348		printf("%04u-%02u-%02u %02u:%02u:%02u ",
349		       t->tm_year + 1900, t->tm_mon + 1, t->tm_mday,
350		       t->tm_hour, t->tm_min, t->tm_sec);
351}
352
353static void time_print_monthdays(uint32_t mask, bool human_readable)
354{
355	unsigned int i, nbdays = 0;
356
357	for (i = 1; i <= 31; ++i)
358		if (mask & (1 << i)) {
359			if (nbdays++ > 0)
360				printf(",");
361			printf("%u", i);
362			if (human_readable)
363				switch (i % 10) {
364					case 1:
365						printf("st");
366						break;
367					case 2:
368						printf("nd");
369						break;
370					case 3:
371						printf("rd");
372						break;
373					default:
374						printf("th");
375						break;
376				}
377		}
378	printf(" ");
379}
380
381static void time_print_weekdays(unsigned int mask)
382{
383	unsigned int i, nbdays = 0;
384
385	for (i = 1; i <= 7; ++i)
386		if (mask & (1 << i)) {
387			if (nbdays > 0)
388				printf(",%s", week_days[i]);
389			else
390				printf("%s", week_days[i]);
391			++nbdays;
392		}
393	printf(" ");
394}
395
396static inline void divide_time(unsigned int fulltime, unsigned int *hours,
397    unsigned int *minutes, unsigned int *seconds)
398{
399	*seconds  = fulltime % 60;
400	fulltime /= 60;
401	*minutes  = fulltime % 60;
402	*hours    = fulltime / 60;
403}
404
405static void time_print(const void *ip, const struct xt_entry_match *match,
406                       int numeric)
407{
408	struct xt_time_info *info = (void *)match->data;
409	unsigned int h, m, s;
410
411	printf("TIME ");
412
413	if (info->daytime_start != XT_TIME_MIN_DAYTIME ||
414	    info->daytime_stop != XT_TIME_MAX_DAYTIME) {
415		divide_time(info->daytime_start, &h, &m, &s);
416		printf("from %02u:%02u:%02u ", h, m, s);
417		divide_time(info->daytime_stop, &h, &m, &s);
418		printf("to %02u:%02u:%02u ", h, m, s);
419	}
420	if (info->weekdays_match != XT_TIME_ALL_WEEKDAYS) {
421		printf("on ");
422		time_print_weekdays(info->weekdays_match);
423	}
424	if (info->monthdays_match != XT_TIME_ALL_MONTHDAYS) {
425		printf("on ");
426		time_print_monthdays(info->monthdays_match, true);
427	}
428	if (info->date_start != 0) {
429		printf("starting from ");
430		time_print_date(info->date_start, NULL);
431	}
432	if (info->date_stop != INT_MAX) {
433		printf("until date ");
434		time_print_date(info->date_stop, NULL);
435	}
436	if (!(info->flags & XT_TIME_LOCAL_TZ))
437		printf("UTC ");
438}
439
440static void time_save(const void *ip, const struct xt_entry_match *match)
441{
442	const struct xt_time_info *info = (const void *)match->data;
443	unsigned int h, m, s;
444
445	if (info->daytime_start != XT_TIME_MIN_DAYTIME ||
446	    info->daytime_stop != XT_TIME_MAX_DAYTIME) {
447		divide_time(info->daytime_start, &h, &m, &s);
448		printf("--timestart %02u:%02u:%02u ", h, m, s);
449		divide_time(info->daytime_stop, &h, &m, &s);
450		printf("--timestop %02u:%02u:%02u ", h, m, s);
451	}
452	if (info->monthdays_match != XT_TIME_ALL_MONTHDAYS) {
453		printf("--monthdays ");
454		time_print_monthdays(info->monthdays_match, false);
455	}
456	if (info->weekdays_match != XT_TIME_ALL_WEEKDAYS) {
457		printf("--weekdays ");
458		time_print_weekdays(info->weekdays_match);
459		printf(" ");
460	}
461	time_print_date(info->date_start, "--datestart");
462	time_print_date(info->date_stop, "--datestop");
463	if (!(info->flags & XT_TIME_LOCAL_TZ))
464		printf("--utc ");
465}
466
467static struct xtables_match time_match = {
468	.name          = "time",
469	.family        = AF_UNSPEC,
470	.version       = IPTABLES_VERSION,
471	.size          = XT_ALIGN(sizeof(struct xt_time_info)),
472	.userspacesize = XT_ALIGN(sizeof(struct xt_time_info)),
473	.help          = time_help,
474	.init          = time_init,
475	.parse         = time_parse,
476	.print         = time_print,
477	.save          = time_save,
478	.extra_opts    = time_opts,
479};
480
481void _init(void)
482{
483	xtables_register_match(&time_match);
484}
485