/*
* 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, bool end)
{
unsigned int month = 1, day = 1, hour = 0, minute = 0, second = 0;
unsigned int year = end ? 2038 : 1970;
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, false);
break;
case O_DATE_STOP:
info->date_stop = time_parse_date(cb->arg, true);
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);
}