libxt_time.c revision 8b7c64d6ba156a99008fcd810cba874c73294333 
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 match 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");
64}
65
66static void time_init(struct xt_entry_match *m)
67{
68	struct xt_time_info *info = (void *)m->data;
69
70	/* By default, we match on every day, every daytime */
71	info->monthdays_match = XT_TIME_ALL_MONTHDAYS;
72	info->weekdays_match  = XT_TIME_ALL_WEEKDAYS;
73	info->daytime_start   = XT_TIME_MIN_DAYTIME;
74	info->daytime_stop    = XT_TIME_MAX_DAYTIME;
75
76	/* ...and have no date-begin or date-end boundary */
77	info->date_start = 0;
78	info->date_stop  = INT_MAX;
79
80	/* local time is default */
81	info->flags |= XT_TIME_LOCAL_TZ;
82}
83
84static time_t time_parse_date(const char *s, bool end)
85{
86	unsigned int month = 1, day = 1, hour = 0, minute = 0, second = 0;
87	unsigned int year  = end ? 2038 : 1970;
88	const char *os = s;
89	struct tm tm;
90	time_t ret;
91	char *e;
92
93	year = strtoul(s, &e, 10);
94	if ((*e != '-' && *e != '\0') || year < 1970 || year > 2038)
95		goto out;
96	if (*e == '\0')
97		goto eval;
98
99	s = e + 1;
100	month = strtoul(s, &e, 10);
101	if ((*e != '-' && *e != '\0') || month > 12)
102		goto out;
103	if (*e == '\0')
104		goto eval;
105
106	s = e + 1;
107	day = strtoul(s, &e, 10);
108	if ((*e != 'T' && *e != '\0') || day > 31)
109		goto out;
110	if (*e == '\0')
111		goto eval;
112
113	s = e + 1;
114	hour = strtoul(s, &e, 10);
115	if ((*e != ':' && *e != '\0') || hour > 23)
116		goto out;
117	if (*e == '\0')
118		goto eval;
119
120	s = e + 1;
121	minute = strtoul(s, &e, 10);
122	if ((*e != ':' && *e != '\0') || minute > 59)
123		goto out;
124	if (*e == '\0')
125		goto eval;
126
127	s = e + 1;
128	second = strtoul(s, &e, 10);
129	if (*e != '\0' || second > 59)
130		goto out;
131
132 eval:
133	tm.tm_year = year - 1900;
134	tm.tm_mon  = month - 1;
135	tm.tm_mday = day;
136	tm.tm_hour = hour;
137	tm.tm_min  = minute;
138	tm.tm_sec  = second;
139	ret = mktime(&tm);
140	if (ret >= 0)
141		return ret;
142	perror("mktime");
143	exit_error(OTHER_PROBLEM, "mktime returned an error");
144
145 out:
146	exit_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	exit_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			exit_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				exit_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			exit_error(PARAMETER_PROBLEM,
241			           "%s is not a valid day specifier", day);
242	}
243
244	return ret;
245}
246
247static int time_parse(int c, char **argv, int invert, unsigned int *flags,
248                      const void *entry, struct xt_entry_match **match)
249{
250	struct xt_time_info *info = (void *)(*match)->data;
251
252	switch (c) {
253	case 'D': /* --datestart */
254		if (*flags & F_DATE_START)
255			exit_error(PARAMETER_PROBLEM,
256			           "Cannot specify --datestart twice");
257		if (invert)
258			exit_error(PARAMETER_PROBLEM,
259			           "Unexpected \"!\" with --datestart");
260		info->date_start = time_parse_date(optarg, false);
261		*flags |= F_DATE_START;
262		return 1;
263	case 'E': /* --datestop */
264		if (*flags & F_DATE_STOP)
265			exit_error(PARAMETER_PROBLEM,
266			           "Cannot specify --datestop more than once");
267		if (invert)
268			exit_error(PARAMETER_PROBLEM,
269			           "unexpected \"!\" with --datestop");
270		info->date_stop = time_parse_date(optarg, true);
271		*flags |= F_DATE_STOP;
272		return 1;
273	case 'X': /* --timestart */
274		if (*flags & F_TIME_START)
275			exit_error(PARAMETER_PROBLEM,
276			           "Cannot specify --timestart more than once");
277		if (invert)
278			exit_error(PARAMETER_PROBLEM,
279			           "Unexpected \"!\" with --timestart");
280		info->daytime_start = time_parse_minutes(optarg);
281		*flags |= F_TIME_START;
282		return 1;
283	case 'Y': /* --timestop */
284		if (*flags & F_TIME_STOP)
285			exit_error(PARAMETER_PROBLEM,
286			           "Cannot specify --timestop more than once");
287		if (invert)
288			exit_error(PARAMETER_PROBLEM,
289			           "Unexpected \"!\" with --timestop");
290		info->daytime_stop = time_parse_minutes(optarg);
291		*flags |= F_TIME_STOP;
292		return 1;
293	case 'l': /* --localtz */
294		if (*flags & F_TIMEZONE)
295			exit_error(PARAMETER_PROBLEM,
296			           "Can only specify exactly one of --localtz or --utc");
297		info->flags |= XT_TIME_LOCAL_TZ;
298		*flags |= F_TIMEZONE;
299		return 1;
300	case 'm': /* --monthdays */
301		if (*flags & F_MONTHDAYS)
302			exit_error(PARAMETER_PROBLEM,
303			           "Cannot specify --monthdays more than once");
304		info->monthdays_match = time_parse_monthdays(optarg);
305		if (invert)
306			info->monthdays_match ^= XT_TIME_ALL_MONTHDAYS;
307		*flags |= F_MONTHDAYS;
308		return 1;
309	case 'w': /* --weekdays */
310		if (*flags & F_WEEKDAYS)
311			exit_error(PARAMETER_PROBLEM,
312			           "Cannot specify --weekdays more than once");
313		info->weekdays_match = time_parse_weekdays(optarg);
314		if (invert)
315			info->weekdays_match ^= XT_TIME_ALL_WEEKDAYS;
316		*flags |= F_WEEKDAYS;
317		return 1;
318	case 'u': /* --utc */
319		if (*flags & F_TIMEZONE)
320			exit_error(PARAMETER_PROBLEM,
321			           "Can only specify exactly one of --localtz or --utc");
322		info->flags &= ~XT_TIME_LOCAL_TZ;
323		*flags |= F_TIMEZONE;
324		return 1;
325	}
326	return 0;
327}
328
329static void time_print_date(time_t date, const char *command)
330{
331	struct tm *t;
332
333	/* If it is the default value, do not print it. */
334	if (date == 0 || date == LONG_MAX)
335		return;
336
337	t = localtime(&date);
338	if (command != NULL)
339		/*
340		 * Need a contiguous string (no whitespaces), hence using
341		 * the ISO 8601 "T" variant.
342		 */
343		printf("%s %04u-%02u-%02uT%02u:%02u:%02u ",
344		       command, t->tm_year + 1900, t->tm_mon + 1,
345		       t->tm_mday, t->tm_hour, t->tm_min, t->tm_sec);
346	else
347		printf("%04u-%02u-%02u %02u:%02u:%02u ",
348		       t->tm_year + 1900, t->tm_mon + 1, t->tm_mday,
349		       t->tm_hour, t->tm_min, t->tm_sec);
350}
351
352static void time_print_monthdays(uint32_t mask, bool human_readable)
353{
354	unsigned int i, nbdays = 0;
355
356	for (i = 1; i <= 31; ++i)
357		if (mask & (1 << i)) {
358			if (nbdays++ > 0)
359				printf(",");
360			printf("%u", i);
361			if (human_readable)
362				switch (i % 10) {
363					case 1:
364						printf("st");
365						break;
366					case 2:
367						printf("nd");
368						break;
369					case 3:
370						printf("rd");
371						break;
372					default:
373						printf("th");
374						break;
375				}
376		}
377	printf(" ");
378}
379
380static void time_print_weekdays(unsigned int mask)
381{
382	unsigned int i, nbdays = 0;
383
384	for (i = 1; i <= 7; ++i)
385		if (mask & (1 << i)) {
386			if (nbdays > 0)
387				printf(",%s", week_days[i]);
388			else
389				printf("%s", week_days[i]);
390			++nbdays;
391		}
392	printf(" ");
393}
394
395static inline void divide_time(unsigned int fulltime, unsigned int *hours,
396    unsigned int *minutes, unsigned int *seconds)
397{
398	*seconds  = fulltime % 60;
399	fulltime /= 60;
400	*minutes  = fulltime % 60;
401	*hours    = fulltime / 60;
402}
403
404static void time_print(const void *ip, const struct xt_entry_match *match,
405                       int numeric)
406{
407	struct xt_time_info *info = (void *)match->data;
408	unsigned int h, m, s;
409
410	printf("TIME ");
411
412	if (info->daytime_start != XT_TIME_MIN_DAYTIME ||
413	    info->daytime_stop != XT_TIME_MAX_DAYTIME) {
414		divide_time(info->daytime_start, &h, &m, &s);
415		printf("from %02u:%02u:%02u ", h, m, s);
416		divide_time(info->daytime_stop, &h, &m, &s);
417		printf("to %02u:%02u:%02u ", h, m, s);
418	}
419	if (info->weekdays_match != XT_TIME_ALL_WEEKDAYS) {
420		printf("on ");
421		time_print_weekdays(info->weekdays_match);
422	}
423	if (info->monthdays_match != XT_TIME_ALL_MONTHDAYS) {
424		printf("on ");
425		time_print_monthdays(info->monthdays_match, true);
426	}
427	if (info->date_start != 0) {
428		printf("starting from ");
429		time_print_date(info->date_start, NULL);
430	}
431	if (info->date_stop != INT_MAX) {
432		printf("until date ");
433		time_print_date(info->date_stop, NULL);
434	}
435	if (!(info->flags & XT_TIME_LOCAL_TZ))
436		printf("UTC ");
437}
438
439static void time_save(const void *ip, const struct xt_entry_match *match)
440{
441	const struct xt_time_info *info = (const void *)match->data;
442	unsigned int h, m, s;
443
444	if (info->daytime_start != XT_TIME_MIN_DAYTIME ||
445	    info->daytime_stop != XT_TIME_MAX_DAYTIME) {
446		divide_time(info->daytime_start, &h, &m, &s);
447		printf("--timestart %02u:%02u:%02u ", h, m, s);
448		divide_time(info->daytime_stop, &h, &m, &s);
449		printf("--timestop %02u:%02u:%02u ", h, m, s);
450	}
451	if (info->monthdays_match != XT_TIME_ALL_MONTHDAYS) {
452		printf("--monthdays ");
453		time_print_monthdays(info->monthdays_match, false);
454	}
455	if (info->weekdays_match != XT_TIME_ALL_WEEKDAYS) {
456		printf("--weekdays ");
457		time_print_weekdays(info->weekdays_match);
458		printf(" ");
459	}
460	time_print_date(info->date_start, "--datestart");
461	time_print_date(info->date_stop, "--datestop");
462	if (!(info->flags & XT_TIME_LOCAL_TZ))
463		printf("--utc ");
464}
465
466static struct xtables_match time_match = {
467	.name          = "time",
468	.family        = AF_UNSPEC,
469	.version       = XTABLES_VERSION,
470	.size          = XT_ALIGN(sizeof(struct xt_time_info)),
471	.userspacesize = XT_ALIGN(sizeof(struct xt_time_info)),
472	.help          = time_help,
473	.init          = time_init,
474	.parse         = time_parse,
475	.print         = time_print,
476	.save          = time_save,
477	.extra_opts    = time_opts,
478};
479
480void _init(void)
481{
482	xtables_register_match(&time_match);
483}
484