/*

 *	libxt_time - iptables part for xt_time

 *	Copyright © CC Computer Consultants GmbH, 2007

 *	Contact: <jengelh@computergmbh.de>

 *

 *	libxt_time.c is free software; you can redistribute it and/or modify

 *	it under the terms of the GNU General Public License as published by

 *	the Free Software Foundation; either version 2 or 3 of the License.

 *

 *	Based on libipt_time.c.

 */

#include <stdio.h>

#include <string.h>

#include <stdlib.h>

#include <time.h>

#include <linux/types.h>

#include <linux/netfilter/xt_time.h>

#include <xtables.h>

enum {

	O_DATE_START = 0,

	O_DATE_STOP,

	O_TIME_START,

	O_TIME_STOP,

	O_TIME_CONTIGUOUS,

	O_MONTHDAYS,

	O_WEEKDAYS,

	O_LOCAL_TZ,

	O_UTC,

	O_KERNEL_TZ,

	F_LOCAL_TZ  = 1 << O_LOCAL_TZ,

	F_UTC       = 1 << O_UTC,

	F_KERNEL_TZ = 1 << O_KERNEL_TZ,

	F_TIME_CONTIGUOUS = 1 << O_TIME_CONTIGUOUS,

};

static const char *const week_days[] = {

	NULL, "Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun",

};

static const struct xt_option_entry time_opts[] = {

	{.name = "datestart", .id = O_DATE_START, .type = XTTYPE_STRING},

	{.name = "datestop", .id = O_DATE_STOP, .type = XTTYPE_STRING},

	{.name = "timestart", .id = O_TIME_START, .type = XTTYPE_STRING},

	{.name = "timestop", .id = O_TIME_STOP, .type = XTTYPE_STRING},

	{.name = "contiguous", .id = O_TIME_CONTIGUOUS, .type = XTTYPE_NONE},

	{.name = "weekdays", .id = O_WEEKDAYS, .type = XTTYPE_STRING,

	 .flags = XTOPT_INVERT},

	{.name = "monthdays", .id = O_MONTHDAYS, .type = XTTYPE_STRING,

	 .flags = XTOPT_INVERT},

	{.name = "localtz", .id = O_LOCAL_TZ, .type = XTTYPE_NONE,

	 .excl = F_UTC},

	{.name = "utc", .id = O_UTC, .type = XTTYPE_NONE,

	 .excl = F_LOCAL_TZ | F_KERNEL_TZ},

	{.name = "kerneltz", .id = O_KERNEL_TZ, .type = XTTYPE_NONE,

	 .excl = F_UTC},

	XTOPT_TABLEEND,

};

static void time_help(void)

{

	printf(

"time match options:\n"

"    --datestart time     Start and stop time, to be given in ISO 8601\n"

"    --datestop time      (YYYY[-MM[-DD[Thh[:mm[:ss]]]]])\n"

"    --timestart time     Start and stop daytime (hh:mm[:ss])\n"

"    --timestop time      (between 00:00:00 and 23:59:59)\n"

"[!] --monthdays value    List of days on which to match, separated by comma\n"

"                         (Possible days: 1 to 31; defaults to all)\n"

"[!] --weekdays value     List of weekdays on which to match, sep. by comma\n"

"                         (Possible days: Mon,Tue,Wed,Thu,Fri,Sat,Sun or 1 to 7\n"

"                         Defaults to all weekdays.)\n"

"    --kerneltz           Work with the kernel timezone instead of UTC\n");

}

static void time_init(struct xt_entry_match *m)

{

	struct xt_time_info *info = (void *)m->data;

	/* By default, we match on every day, every daytime */

	info->monthdays_match = XT_TIME_ALL_MONTHDAYS;

	info->weekdays_match  = XT_TIME_ALL_WEEKDAYS;

	info->daytime_start   = XT_TIME_MIN_DAYTIME;

	info->daytime_stop    = XT_TIME_MAX_DAYTIME;

	/* ...and have no date-begin or date-end boundary */

	info->date_start = 0;

	info->date_stop  = INT_MAX;

}

static time_t time_parse_date(const char *s)

{

	unsigned int month = 1, day = 1, hour = 0, minute = 0, second = 0;

	unsigned int year;

	const char *os = s;

	struct tm tm;

	time_t ret;

	char *e;

	year = strtoul(s, &e, 10);

	if ((*e != '-' && *e != '\0') || year < 1970 || year > 2038)

		goto out;

	if (*e == '\0')

		goto eval;

	s = e + 1;

	month = strtoul(s, &e, 10);

	if ((*e != '-' && *e != '\0') || month > 12)

		goto out;

	if (*e == '\0')

		goto eval;

	s = e + 1;

	day = strtoul(s, &e, 10);

	if ((*e != 'T' && *e != '\0') || day > 31)

		goto out;

	if (*e == '\0')

		goto eval;

	s = e + 1;

	hour = strtoul(s, &e, 10);

	if ((*e != ':' && *e != '\0') || hour > 23)

		goto out;

	if (*e == '\0')

		goto eval;

	s = e + 1;

	minute = strtoul(s, &e, 10);

	if ((*e != ':' && *e != '\0') || minute > 59)

		goto out;

	if (*e == '\0')

		goto eval;

	s = e + 1;

	second = strtoul(s, &e, 10);

	if (*e != '\0' || second > 59)

		goto out;

 eval:

	tm.tm_year = year - 1900;

	tm.tm_mon  = month - 1;

	tm.tm_mday = day;

	tm.tm_hour = hour;

	tm.tm_min  = minute;

	tm.tm_sec  = second;

	tm.tm_isdst = 0;

	/*

	 * Offsetting, if any, is done by xt_time.ko,

	 * so we have to disable it here in userspace.

	 */

	setenv("TZ", "UTC", true);

	tzset();

	ret = mktime(&tm;;

	if (ret >= 0)

		return ret;

	perror("mktime");

	xtables_error(OTHER_PROBLEM, "mktime returned an error");

 out:

	xtables_error(PARAMETER_PROBLEM, "Invalid date \"%s\" specified. Should "

	           "be YYYY[-MM[-DD[Thh[:mm[:ss]]]]]", os);

	return -1;

}

static unsigned int time_parse_minutes(const char *s)

{

	unsigned int hour, minute, second = 0;

	char *e;

	hour = strtoul(s, &e, 10);

	if (*e != ':' || hour > 23)

		goto out;

	s = e + 1;

	minute = strtoul(s, &e, 10);

	if ((*e != ':' && *e != '\0') || minute > 59)

		goto out;

	if (*e == '\0')

		goto eval;

	s = e + 1;

	second = strtoul(s, &e, 10);

	if (*e != '\0' || second > 59)

		goto out;

 eval:

	return 60 * 60 * hour + 60 * minute + second;

 out:

	xtables_error(PARAMETER_PROBLEM, "invalid time \"%s\" specified, "

	           "should be hh:mm[:ss] format and within the boundaries", s);

	return -1;

}

static const char *my_strseg(char *buf, unsigned int buflen,

    const char **arg, char delim)

{

	const char *sep;

	if (*arg == NULL || **arg == '\0')

		return NULL;

	sep = strchr(*arg, delim);

	if (sep == NULL) {

		snprintf(buf, buflen, "%s", *arg);

		*arg = NULL;

		return buf;

	}

	snprintf(buf, buflen, "%.*s", (unsigned int)(sep - *arg), *arg);

	*arg = sep + 1;

	return buf;

}

static uint32_t time_parse_monthdays(const char *arg)

{

	char day[3], *err = NULL;

	uint32_t ret = 0;

	unsigned int i;

	while (my_strseg(day, sizeof(day), &arg, ',') != NULL) {

		i = strtoul(day, &err, 0);

		if ((*err != ',' && *err != '\0') || i > 31)

			xtables_error(PARAMETER_PROBLEM,

			           "%s is not a valid day for --monthdays", day);

		ret |= 1 << i;

	}

	return ret;

}

static unsigned int time_parse_weekdays(const char *arg)

{

	char day[4], *err = NULL;

	unsigned int i, ret = 0;

	bool valid;

	while (my_strseg(day, sizeof(day), &arg, ',') != NULL) {

		i = strtoul(day, &err, 0);

		if (*err == '\0') {

			if (i == 0)

				xtables_error(PARAMETER_PROBLEM,

				           "No, the week does NOT begin with Sunday.");

			ret |= 1 << i;

			continue;

		}

		valid = false;

		for (i = 1; i < ARRAY_SIZE(week_days); ++i)

			if (strncmp(day, week_days[i], 2) == 0) {

				ret |= 1 << i;

				valid = true;

			}

		if (!valid)

			xtables_error(PARAMETER_PROBLEM,

			           "%s is not a valid day specifier", day);

	}

	return ret;

}

static void time_parse(struct xt_option_call *cb)

{

	struct xt_time_info *info = cb->data;

	xtables_option_parse(cb);

	switch (cb->entry->id) {

	case O_DATE_START:

		info->date_start = time_parse_date(cb->arg);

		break;

	case O_DATE_STOP:

		info->date_stop = time_parse_date(cb->arg);

		break;

	case O_TIME_START:

		info->daytime_start = time_parse_minutes(cb->arg);

		break;

	case O_TIME_STOP:

		info->daytime_stop = time_parse_minutes(cb->arg);

		break;

	case O_TIME_CONTIGUOUS:

		info->flags |= XT_TIME_CONTIGUOUS;

		break;

	case O_LOCAL_TZ:

		fprintf(stderr, "WARNING: --localtz is being replaced by "

		        "--kerneltz, since \"local\" is ambiguous. Note the "

		        "kernel timezone has caveats - "

		        "see manpage for details.\n");

		/* fallthrough */

	case O_KERNEL_TZ:

		info->flags |= XT_TIME_LOCAL_TZ;

		break;

	case O_MONTHDAYS:

		info->monthdays_match = time_parse_monthdays(cb->arg);

		if (cb->invert)

			info->monthdays_match ^= XT_TIME_ALL_MONTHDAYS;

		break;

	case O_WEEKDAYS:

		info->weekdays_match = time_parse_weekdays(cb->arg);

		if (cb->invert)

			info->weekdays_match ^= XT_TIME_ALL_WEEKDAYS;

		break;

	}

}

static void time_print_date(time_t date, const char *command)

{

	struct tm *t;

	/* If it is the default value, do not print it. */

	if (date == 0 || date == LONG_MAX)

		return;

	t = gmtime(&date);

	if (command != NULL)

		/*

		 * Need a contiguous string (no whitespaces), hence using

		 * the ISO 8601 "T" variant.

		 */

		printf(" %s %04u-%02u-%02uT%02u:%02u:%02u",

		       command, t->tm_year + 1900, t->tm_mon + 1,

		       t->tm_mday, t->tm_hour, t->tm_min, t->tm_sec);

	else

		printf(" %04u-%02u-%02u %02u:%02u:%02u",

		       t->tm_year + 1900, t->tm_mon + 1, t->tm_mday,

		       t->tm_hour, t->tm_min, t->tm_sec);

}

static void time_print_monthdays(uint32_t mask, bool human_readable)

{

	unsigned int i, nbdays = 0;

	printf(" ");

	for (i = 1; i <= 31; ++i)

		if (mask & (1 << i)) {

			if (nbdays++ > 0)

				printf(",");

			printf("%u", i);

			if (human_readable)

				switch (i % 10) {

					case 1:

						printf("st");

						break;

					case 2:

						printf("nd");

						break;

					case 3:

						printf("rd");

						break;

					default:

						printf("th");

						break;

				}

		}

}

static void time_print_weekdays(unsigned int mask)

{

	unsigned int i, nbdays = 0;

	printf(" ");

	for (i = 1; i <= 7; ++i)

		if (mask & (1 << i)) {

			if (nbdays > 0)

				printf(",%s", week_days[i]);

			else

				printf("%s", week_days[i]);

			++nbdays;

		}

}

static inline void divide_time(unsigned int fulltime, unsigned int *hours,

    unsigned int *minutes, unsigned int *seconds)

{

	*seconds  = fulltime % 60;

	fulltime /= 60;

	*minutes  = fulltime % 60;

	*hours    = fulltime / 60;

}

static void time_print(const void *ip, const struct xt_entry_match *match,

                       int numeric)

{

	const struct xt_time_info *info = (const void *)match->data;

	unsigned int h, m, s;

	printf(" TIME");

	if (info->daytime_start != XT_TIME_MIN_DAYTIME ||

	    info->daytime_stop != XT_TIME_MAX_DAYTIME) {

		divide_time(info->daytime_start, &h, &m, &s);

		printf(" from %02u:%02u:%02u", h, m, s);

		divide_time(info->daytime_stop, &h, &m, &s);

		printf(" to %02u:%02u:%02u", h, m, s);

	}

	if (info->weekdays_match != XT_TIME_ALL_WEEKDAYS) {

		printf(" on");

		time_print_weekdays(info->weekdays_match);

	}

	if (info->monthdays_match != XT_TIME_ALL_MONTHDAYS) {

		printf(" on");

		time_print_monthdays(info->monthdays_match, true);

	}

	if (info->date_start != 0) {

		printf(" starting from");

		time_print_date(info->date_start, NULL);

	}

	if (info->date_stop != INT_MAX) {

		printf(" until date");

		time_print_date(info->date_stop, NULL);

	}

	if (!(info->flags & XT_TIME_LOCAL_TZ))

		printf(" UTC");

	if (info->flags & XT_TIME_CONTIGUOUS)

		printf(" contiguous");

}

static void time_save(const void *ip, const struct xt_entry_match *match)

{

	const struct xt_time_info *info = (const void *)match->data;

	unsigned int h, m, s;

	if (info->daytime_start != XT_TIME_MIN_DAYTIME ||

	    info->daytime_stop != XT_TIME_MAX_DAYTIME) {

		divide_time(info->daytime_start, &h, &m, &s);

		printf(" --timestart %02u:%02u:%02u", h, m, s);

		divide_time(info->daytime_stop, &h, &m, &s);

		printf(" --timestop %02u:%02u:%02u", h, m, s);

	}

	if (info->monthdays_match != XT_TIME_ALL_MONTHDAYS) {

		printf(" --monthdays");

		time_print_monthdays(info->monthdays_match, false);

	}

	if (info->weekdays_match != XT_TIME_ALL_WEEKDAYS) {

		printf(" --weekdays");

		time_print_weekdays(info->weekdays_match);

	}

	time_print_date(info->date_start, "--datestart");

	time_print_date(info->date_stop, "--datestop");

	if (info->flags & XT_TIME_LOCAL_TZ)

		printf(" --kerneltz");

	if (info->flags & XT_TIME_CONTIGUOUS)

		printf(" --contiguous");

}

static void time_check(struct xt_fcheck_call *cb)

{

	const struct xt_time_info *info = (const void *) cb->data;

	if ((cb->xflags & F_TIME_CONTIGUOUS) &&

	     info->daytime_start < info->daytime_stop)

		xtables_error(PARAMETER_PROBLEM,

			"time: --contiguous only makes sense when stoptime is smaller than starttime");

}

static struct xtables_match time_match = {

	.name          = "time",

	.family        = NFPROTO_UNSPEC,

	.version       = XTABLES_VERSION,

	.size          = XT_ALIGN(sizeof(struct xt_time_info)),

	.userspacesize = XT_ALIGN(sizeof(struct xt_time_info)),

	.help          = time_help,

	.init          = time_init,

	.print         = time_print,

	.save          = time_save,

	.x6_parse      = time_parse,

	.x6_fcheck     = time_check,

	.x6_options    = time_opts,

};

void _init(void)

{

	xtables_register_match(&time_match);

}