extensions/libxt_time.c

   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
  20 enum {
  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         O_KERNEL_TZ,
  30         F_LOCAL_TZ  = 1 << O_LOCAL_TZ,
  31         F_UTC       = 1 << O_UTC,
  32         F_KERNEL_TZ = 1 << O_KERNEL_TZ,
  33 };
  34
  35 static const char *const week_days[] = {
  36         NULL, "Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun",
  37 };
  38
  39 static const struct xt_option_entry time_opts[] = {
  40         {.name = "datestart", .id = O_DATE_START, .type = XTTYPE_STRING},
  41         {.name = "datestop", .id = O_DATE_STOP, .type = XTTYPE_STRING},
  42         {.name = "timestart", .id = O_TIME_START, .type = XTTYPE_STRING},
  43         {.name = "timestop", .id = O_TIME_STOP, .type = XTTYPE_STRING},
  44         {.name = "weekdays", .id = O_WEEKDAYS, .type = XTTYPE_STRING,
  45          .flags = XTOPT_INVERT},
  46         {.name = "monthdays", .id = O_MONTHDAYS, .type = XTTYPE_STRING,
  47          .flags = XTOPT_INVERT},
  48         {.name = "localtz", .id = O_LOCAL_TZ, .type = XTTYPE_NONE,
  49          .excl = F_UTC},
  50         {.name = "utc", .id = O_UTC, .type = XTTYPE_NONE,
  51          .excl = F_LOCAL_TZ | F_KERNEL_TZ},
  52         {.name = "kerneltz", .id = O_KERNEL_TZ, .type = XTTYPE_NONE,
  53          .excl = F_UTC},
  54         XTOPT_TABLEEND,
  55 };
  56
  57 static void time_help(void)
  58 {
  59         printf(
  60 "time match options:\n"
  61 "    --datestart time     Start and stop time, to be given in ISO 8601\n"
  62 "    --datestop time      (YYYY[-MM[-DD[Thh[:mm[:ss]]]]])\n"
  63 "    --timestart time     Start and stop daytime (hh:mm[:ss])\n"
  64 "    --timestop time      (between 00:00:00 and 23:59:59)\n"
  65 "[!] --monthdays value    List of days on which to match, separated by comma\n"
  66 "                         (Possible days: 1 to 31; defaults to all)\n"
  67 "[!] --weekdays value     List of weekdays on which to match, sep. by comma\n"
  68 "                         (Possible days: Mon,Tue,Wed,Thu,Fri,Sat,Sun or 1 to 7\n"
  69 "                         Defaults to all weekdays.)\n"
  70 "    --kerneltz           Work with the kernel timezone instead of UTC\n");
  71 }
  72
  73 static void time_init(struct xt_entry_match *m)
  74 {
  75         struct xt_time_info *info = (void *)m->data;
  76
  77         /* By default, we match on every day, every daytime */
  78         info->monthdays_match = XT_TIME_ALL_MONTHDAYS;
  79         info->weekdays_match  = XT_TIME_ALL_WEEKDAYS;
  80         info->daytime_start   = XT_TIME_MIN_DAYTIME;
  81         info->daytime_stop    = XT_TIME_MAX_DAYTIME;
  82
  83         /* ...and have no date-begin or date-end boundary */
  84         info->date_start = 0;
  85         info->date_stop  = INT_MAX;
  86 }
  87
  88 static time_t time_parse_date(const char *s, bool end)
  89 {
  90         unsigned int month = 1, day = 1, hour = 0, minute = 0, second = 0;
  91         unsigned int year  = end ? 2038 : 1970;
  92         const char *os = s;
  93         struct tm tm;
  94         time_t ret;
  95         char *e;
  96
  97         year = strtoul(s, &e, 10);
  98         if ((*e != '-' && *e != '\0') || year < 1970 || year > 2038)
  99                 goto out;
 100         if (*e == '\0')
 101                 goto eval;
 102
 103         s = e + 1;
 104         month = strtoul(s, &e, 10);
 105         if ((*e != '-' && *e != '\0') || month > 12)
 106                 goto out;
 107         if (*e == '\0')
 108                 goto eval;
 109
 110         s = e + 1;
 111         day = strtoul(s, &e, 10);
 112         if ((*e != 'T' && *e != '\0') || day > 31)
 113                 goto out;
 114         if (*e == '\0')
 115                 goto eval;
 116
 117         s = e + 1;
 118         hour = strtoul(s, &e, 10);
 119         if ((*e != ':' && *e != '\0') || hour > 23)
 120                 goto out;
 121         if (*e == '\0')
 122                 goto eval;
 123
 124         s = e + 1;
 125         minute = strtoul(s, &e, 10);
 126         if ((*e != ':' && *e != '\0') || minute > 59)
 127                 goto out;
 128         if (*e == '\0')
 129                 goto eval;
 130
 131         s = e + 1;
 132         second = strtoul(s, &e, 10);
 133         if (*e != '\0' || second > 59)
 134                 goto out;
 135
 136  eval:
 137         tm.tm_year = year - 1900;
 138         tm.tm_mon  = month - 1;
 139         tm.tm_mday = day;
 140         tm.tm_hour = hour;
 141         tm.tm_min  = minute;
 142         tm.tm_sec  = second;
 143         tm.tm_isdst = 0;
 144         /*
 145          * Offsetting, if any, is done by xt_time.ko,
 146          * so we have to disable it here in userspace.
 147          */
 148         setenv("TZ", "UTC", true);
 149         tzset();
 150         ret = mktime(&tm);
 151         if (ret >= 0)
 152                 return ret;
 153         perror("mktime");
 154         xtables_error(OTHER_PROBLEM, "mktime returned an error");
 155
 156  out:
 157         xtables_error(PARAMETER_PROBLEM, "Invalid date \"%s\" specified. Should "
 158                    "be YYYY[-MM[-DD[Thh[:mm[:ss]]]]]", os);
 159         return -1;
 160 }
 161
 162 static unsigned int time_parse_minutes(const char *s)
 163 {
 164         unsigned int hour, minute, second = 0;
 165         char *e;
 166
 167         hour = strtoul(s, &e, 10);
 168         if (*e != ':' || hour > 23)
 169                 goto out;
 170
 171         s = e + 1;
 172         minute = strtoul(s, &e, 10);
 173         if ((*e != ':' && *e != '\0') || minute > 59)
 174                 goto out;
 175         if (*e == '\0')
 176                 goto eval;
 177
 178         s = e + 1;
 179         second = strtoul(s, &e, 10);
 180         if (*e != '\0' || second > 59)
 181                 goto out;
 182
 183  eval:
 184         return 60 * 60 * hour + 60 * minute + second;
 185
 186  out:
 187         xtables_error(PARAMETER_PROBLEM, "invalid time \"%s\" specified, "
 188                    "should be hh:mm[:ss] format and within the boundaries", s);
 189         return -1;
 190 }
 191
 192 static const char *my_strseg(char *buf, unsigned int buflen,
 193     const char **arg, char delim)
 194 {
 195         const char *sep;
 196
 197         if (*arg == NULL || **arg == '\0')
 198                 return NULL;
 199         sep = strchr(*arg, delim);
 200         if (sep == NULL) {
 201                 snprintf(buf, buflen, "%s", *arg);
 202                 *arg = NULL;
 203                 return buf;
 204         }
 205         snprintf(buf, buflen, "%.*s", (unsigned int)(sep - *arg), *arg);
 206         *arg = sep + 1;
 207         return buf;
 208 }
 209
 210 static uint32_t time_parse_monthdays(const char *arg)
 211 {
 212         char day[3], *err = NULL;
 213         uint32_t ret = 0;
 214         unsigned int i;
 215
 216         while (my_strseg(day, sizeof(day), &arg, ',') != NULL) {
 217                 i = strtoul(day, &err, 0);
 218                 if ((*err != ',' && *err != '\0') || i > 31)
 219                         xtables_error(PARAMETER_PROBLEM,
 220                                    "%s is not a valid day for --monthdays", day);
 221                 ret |= 1 << i;
 222         }
 223
 224         return ret;
 225 }
 226
 227 static unsigned int time_parse_weekdays(const char *arg)
 228 {
 229         char day[4], *err = NULL;
 230         unsigned int i, ret = 0;
 231         bool valid;
 232
 233         while (my_strseg(day, sizeof(day), &arg, ',') != NULL) {
 234                 i = strtoul(day, &err, 0);
 235                 if (*err == '\0') {
 236                         if (i == 0)
 237                                 xtables_error(PARAMETER_PROBLEM,
 238                                            "No, the week does NOT begin with Sunday.");
 239                         ret |= 1 << i;
 240                         continue;
 241                 }
 242
 243                 valid = false;
 244                 for (i = 1; i < ARRAY_SIZE(week_days); ++i)
 245                         if (strncmp(day, week_days[i], 2) == 0) {
 246                                 ret |= 1 << i;
 247                                 valid = true;
 248                         }
 249
 250                 if (!valid)
 251                         xtables_error(PARAMETER_PROBLEM,
 252                                    "%s is not a valid day specifier", day);
 253         }
 254
 255         return ret;
 256 }
 257
 258 static void time_parse(struct xt_option_call *cb)
 259 {
 260         struct xt_time_info *info = cb->data;
 261
 262         xtables_option_parse(cb);
 263         switch (cb->entry->id) {
 264         case O_DATE_START:
 265                 info->date_start = time_parse_date(cb->arg, false);
 266                 break;
 267         case O_DATE_STOP:
 268                 info->date_stop = time_parse_date(cb->arg, true);
 269                 break;
 270         case O_TIME_START:
 271                 info->daytime_start = time_parse_minutes(cb->arg);
 272                 break;
 273         case O_TIME_STOP:
 274                 info->daytime_stop = time_parse_minutes(cb->arg);
 275                 break;
 276         case O_LOCAL_TZ:
 277                 fprintf(stderr, "WARNING: --localtz is being replaced by "
 278                         "--kerneltz, since \"local\" is ambiguous. Note the "
 279                         "kernel timezone has caveats - "
 280                         "see manpage for details.\n");
 281                 /* fallthrough */
 282         case O_KERNEL_TZ:
 283                 info->flags |= XT_TIME_LOCAL_TZ;
 284                 break;
 285         case O_MONTHDAYS:
 286                 info->monthdays_match = time_parse_monthdays(cb->arg);
 287                 if (cb->invert)
 288                         info->monthdays_match ^= XT_TIME_ALL_MONTHDAYS;
 289                 break;
 290         case O_WEEKDAYS:
 291                 info->weekdays_match = time_parse_weekdays(cb->arg);
 292                 if (cb->invert)
 293                         info->weekdays_match ^= XT_TIME_ALL_WEEKDAYS;
 294                 break;
 295         }
 296 }
 297
 298 static void time_print_date(time_t date, const char *command)
 299 {
 300         struct tm *t;
 301
 302         /* If it is the default value, do not print it. */
 303         if (date == 0 || date == LONG_MAX)
 304                 return;
 305
 306         t = gmtime(&date);
 307         if (command != NULL)
 308                 /*
 309                  * Need a contiguous string (no whitespaces), hence using
 310                  * the ISO 8601 "T" variant.
 311                  */
 312                 printf(" %s %04u-%02u-%02uT%02u:%02u:%02u",
 313                        command, t->tm_year + 1900, t->tm_mon + 1,
 314                        t->tm_mday, t->tm_hour, t->tm_min, t->tm_sec);
 315         else
 316                 printf(" %04u-%02u-%02u %02u:%02u:%02u",
 317                        t->tm_year + 1900, t->tm_mon + 1, t->tm_mday,
 318                        t->tm_hour, t->tm_min, t->tm_sec);
 319 }
 320
 321 static void time_print_monthdays(uint32_t mask, bool human_readable)
 322 {
 323         unsigned int i, nbdays = 0;
 324
 325         printf(" ");
 326         for (i = 1; i <= 31; ++i)
 327                 if (mask & (1 << i)) {
 328                         if (nbdays++ > 0)
 329                                 printf(",");
 330                         printf("%u", i);
 331                         if (human_readable)
 332                                 switch (i % 10) {
 333                                         case 1:
 334                                                 printf("st");
 335                                                 break;
 336                                         case 2:
 337                                                 printf("nd");
 338                                                 break;
 339                                         case 3:
 340                                                 printf("rd");
 341                                                 break;
 342                                         default:
 343                                                 printf("th");
 344                                                 break;
 345                                 }
 346                 }
 347 }
 348
 349 static void time_print_weekdays(unsigned int mask)
 350 {
 351         unsigned int i, nbdays = 0;
 352
 353         printf(" ");
 354         for (i = 1; i <= 7; ++i)
 355                 if (mask & (1 << i)) {
 356                         if (nbdays > 0)
 357                                 printf(",%s", week_days[i]);
 358                         else
 359                                 printf("%s", week_days[i]);
 360                         ++nbdays;
 361                 }
 362 }
 363
 364 static inline void divide_time(unsigned int fulltime, unsigned int *hours,
 365     unsigned int *minutes, unsigned int *seconds)
 366 {
 367         *seconds  = fulltime % 60;
 368         fulltime /= 60;
 369         *minutes  = fulltime % 60;
 370         *hours    = fulltime / 60;
 371 }
 372
 373 static void time_print(const void *ip, const struct xt_entry_match *match,
 374                        int numeric)
 375 {
 376         const struct xt_time_info *info = (const void *)match->data;
 377         unsigned int h, m, s;
 378
 379         printf(" TIME");
 380
 381         if (info->daytime_start != XT_TIME_MIN_DAYTIME ||
 382             info->daytime_stop != XT_TIME_MAX_DAYTIME) {
 383                 divide_time(info->daytime_start, &h, &m, &s);
 384                 printf(" from %02u:%02u:%02u", h, m, s);
 385                 divide_time(info->daytime_stop, &h, &m, &s);
 386                 printf(" to %02u:%02u:%02u", h, m, s);
 387         }
 388         if (info->weekdays_match != XT_TIME_ALL_WEEKDAYS) {
 389                 printf(" on");
 390                 time_print_weekdays(info->weekdays_match);
 391         }
 392         if (info->monthdays_match != XT_TIME_ALL_MONTHDAYS) {
 393                 printf(" on");
 394                 time_print_monthdays(info->monthdays_match, true);
 395         }
 396         if (info->date_start != 0) {
 397                 printf(" starting from");
 398                 time_print_date(info->date_start, NULL);
 399         }
 400         if (info->date_stop != INT_MAX) {
 401                 printf(" until date");
 402                 time_print_date(info->date_stop, NULL);
 403         }
 404         if (!(info->flags & XT_TIME_LOCAL_TZ))
 405                 printf(" UTC");
 406 }
 407
 408 static void time_save(const void *ip, const struct xt_entry_match *match)
 409 {
 410         const struct xt_time_info *info = (const void *)match->data;
 411         unsigned int h, m, s;
 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(" --timestart %02u:%02u:%02u", h, m, s);
 417                 divide_time(info->daytime_stop, &h, &m, &s);
 418                 printf(" --timestop %02u:%02u:%02u", h, m, s);
 419         }
 420         if (info->monthdays_match != XT_TIME_ALL_MONTHDAYS) {
 421                 printf(" --monthdays");
 422                 time_print_monthdays(info->monthdays_match, false);
 423         }
 424         if (info->weekdays_match != XT_TIME_ALL_WEEKDAYS) {
 425                 printf(" --weekdays");
 426                 time_print_weekdays(info->weekdays_match);
 427         }
 428         time_print_date(info->date_start, "--datestart");
 429         time_print_date(info->date_stop, "--datestop");
 430         if (info->flags & XT_TIME_LOCAL_TZ)
 431                 printf(" --kerneltz");
 432 }
 433
 434 static struct xtables_match time_match = {
 435         .name          = "time",
 436         .family        = NFPROTO_UNSPEC,
 437         .version       = XTABLES_VERSION,
 438         .size          = XT_ALIGN(sizeof(struct xt_time_info)),
 439         .userspacesize = XT_ALIGN(sizeof(struct xt_time_info)),
 440         .help          = time_help,
 441         .init          = time_init,
 442         .print         = time_print,
 443         .save          = time_save,
 444         .x6_parse      = time_parse,
 445         .x6_options    = time_opts,
 446 };
 447
 448 void _init(void)
 449 {
 450         xtables_register_match(&time_match);
 451 }