release/src/router/iptables/extensions/libipt_hashlimit.c

   1 /* iptables match extension for limiting packets per destination
   2  *
   3  * (C) 2003-2004 by Harald Welte <laforge@netfilter.org>
   4  *
   5  * Development of this code was funded by Astaro AG, http://www.astaro.com/
   6  *
   7  * Based on ipt_limit.c by
   8  * Jérôme de Vivie   <devivie@info.enserb.u-bordeaux.fr>
   9  * Hervé Eychenne    <rv@wallfire.org>
  10  *
  11  * Error corections by nmalykh@bilim.com (22.01.2005)
  12  */
  13
  14 #include <stdio.h>
  15 #include <string.h>
  16 #include <stdlib.h>
  17 #include <getopt.h>
  18 #include <iptables.h>
  19 #include <stddef.h>
  20 #include <linux/netfilter_ipv4/ip_tables.h>
  21 #include <linux/netfilter_ipv4/ipt_hashlimit.h>
  22
  23 #define IPT_HASHLIMIT_BURST     5
  24
  25 /* miliseconds */
  26 #define IPT_HASHLIMIT_GCINTERVAL        1000
  27 #define IPT_HASHLIMIT_EXPIRE    10000
  28
  29 /* Function which prints out usage message. */
  30 static void
  31 help(void)
  32 {
  33         printf(
  34 "hashlimit v%s options:\n"
  35 "--hashlimit <avg>              max average match rate\n"
  36 "                                [Packets per second unless followed by \n"
  37 "                                /sec /minute /hour /day postfixes]\n"
  38 "--hashlimit-mode <mode>                mode is a comma-separated list of\n"
  39 "                                       dstip,srcip,dstport,srcport\n"
  40 "--hashlimit-name <name>                name for /proc/net/ipt_hashlimit/\n"
  41 "[--hashlimit-burst <num>]      number to match in a burst, default %u\n"
  42 "[--hashlimit-htable-size <num>]        number of hashtable buckets\n"
  43 "[--hashlimit-htable-max <num>] number of hashtable entries\n"
  44 "[--hashlimit-htable-gcinterval]        interval between garbage collection runs\n"
  45 "[--hashlimit-htable-expire]    after which time are idle entries expired?\n"
  46 "\n", IPTABLES_VERSION, IPT_HASHLIMIT_BURST);
  47 }
  48
  49 static struct option opts[] = {
  50         { "hashlimit", 1, 0, '%' },
  51         { "hashlimit-burst", 1, 0, '$' },
  52         { "hashlimit-htable-size", 1, 0, '&' },
  53         { "hashlimit-htable-max", 1, 0, '*' },
  54         { "hashlimit-htable-gcinterval", 1, 0, '(' },
  55         { "hashlimit-htable-expire", 1, 0, ')' },
  56         { "hashlimit-mode", 1, 0, '_' },
  57         { "hashlimit-name", 1, 0, '"' },
  58         { 0 }
  59 };
  60
  61 static
  62 int parse_rate(const char *rate, u_int32_t *val)
  63 {
  64         const char *delim;
  65         u_int32_t r;
  66         u_int32_t mult = 1;  /* Seconds by default. */
  67
  68         delim = strchr(rate, '/');
  69         if (delim) {
  70                 if (strlen(delim+1) == 0)
  71                         return 0;
  72
  73                 if (strncasecmp(delim+1, "second", strlen(delim+1)) == 0)
  74                         mult = 1;
  75                 else if (strncasecmp(delim+1, "minute", strlen(delim+1)) == 0)
  76                         mult = 60;
  77                 else if (strncasecmp(delim+1, "hour", strlen(delim+1)) == 0)
  78                         mult = 60*60;
  79                 else if (strncasecmp(delim+1, "day", strlen(delim+1)) == 0)
  80                         mult = 24*60*60;
  81                 else
  82                         return 0;
  83         }
  84         r = atoi(rate);
  85         if (!r)
  86                 return 0;
  87
  88         /* This would get mapped to infinite (1/day is minimum they
  89            can specify, so we're ok at that end). */
  90         if (r / mult > IPT_HASHLIMIT_SCALE)
  91                 exit_error(PARAMETER_PROBLEM, "Rate too fast `%s'\n", rate);
  92
  93         *val = IPT_HASHLIMIT_SCALE * mult / r;
  94         return 1;
  95 }
  96
  97 /* Initialize the match. */
  98 static void
  99 init(struct ipt_entry_match *m, unsigned int *nfcache)
 100 {
 101         struct ipt_hashlimit_info *r = (struct ipt_hashlimit_info *)m->data;
 102
 103         r->cfg.burst = IPT_HASHLIMIT_BURST;
 104         r->cfg.gc_interval = IPT_HASHLIMIT_GCINTERVAL;
 105         r->cfg.expire = IPT_HASHLIMIT_EXPIRE;
 106
 107 }
 108
 109
 110 /* Parse a 'mode' parameter into the required bitmask */
 111 static int parse_mode(struct ipt_hashlimit_info *r, char *optarg)
 112 {
 113         char *tok;
 114         char *arg = strdup(optarg);
 115
 116         if (!arg)
 117                 return -1;
 118
 119         r->cfg.mode = 0;
 120
 121         for (tok = strtok(arg, ",|");
 122              tok;
 123              tok = strtok(NULL, ",|")) {
 124                 if (!strcmp(tok, "dstip"))
 125                         r->cfg.mode |= IPT_HASHLIMIT_HASH_DIP;
 126                 else if (!strcmp(tok, "srcip"))
 127                         r->cfg.mode |= IPT_HASHLIMIT_HASH_SIP;
 128                 else if (!strcmp(tok, "srcport"))
 129                         r->cfg.mode |= IPT_HASHLIMIT_HASH_SPT;
 130                 else if (!strcmp(tok, "dstport"))
 131                         r->cfg.mode |= IPT_HASHLIMIT_HASH_DPT;
 132                 else {
 133                         free(arg);
 134                         return -1;
 135                 }
 136         }
 137         free(arg);
 138         return 0;
 139 }
 140
 141 #define PARAM_LIMIT             0x00000001
 142 #define PARAM_BURST             0x00000002
 143 #define PARAM_MODE              0x00000004
 144 #define PARAM_NAME              0x00000008
 145 #define PARAM_SIZE              0x00000010
 146 #define PARAM_MAX               0x00000020
 147 #define PARAM_GCINTERVAL        0x00000040
 148 #define PARAM_EXPIRE            0x00000080
 149
 150 /* Function which parses command options; returns true if it
 151    ate an option */
 152 static int
 153 parse(int c, char **argv, int invert, unsigned int *flags,
 154       const struct ipt_entry *entry,
 155       unsigned int *nfcache,
 156       struct ipt_entry_match **match)
 157 {
 158         struct ipt_hashlimit_info *r =
 159                         (struct ipt_hashlimit_info *)(*match)->data;
 160         unsigned int num;
 161
 162         switch(c) {
 163         case '%':
 164                 if (check_inverse(argv[optind-1], &invert, &optind, 0)) break;
 165                 if (!parse_rate(optarg, &r->cfg.avg))
 166                         exit_error(PARAMETER_PROBLEM,
 167                                    "bad rate `%s'", optarg);
 168                 *flags |= PARAM_LIMIT;
 169                 break;
 170
 171         case '$':
 172                 if (check_inverse(argv[optind-1], &invert, &optind, 0)) break;
 173                 if (string_to_number(optarg, 0, 10000, &num) == -1)
 174                         exit_error(PARAMETER_PROBLEM,
 175                                    "bad --hashlimit-burst `%s'", optarg);
 176                 r->cfg.burst = num;
 177                 *flags |= PARAM_BURST;
 178                 break;
 179         case '&':
 180                 if (check_inverse(argv[optind-1], &invert, &optind, 0)) break;
 181                 if (string_to_number(optarg, 0, 0xffffffff, &num) == -1)
 182                         exit_error(PARAMETER_PROBLEM,
 183                                 "bad --hashlimit-htable-size: `%s'", optarg);
 184                 r->cfg.size = num;
 185                 *flags |= PARAM_SIZE;
 186                 break;
 187         case '*':
 188                 if (check_inverse(argv[optind-1], &invert, &optind, 0)) break;
 189                 if (string_to_number(optarg, 0, 0xffffffff, &num) == -1)
 190                         exit_error(PARAMETER_PROBLEM,
 191                                 "bad --hashlimit-htable-max: `%s'", optarg);
 192                 r->cfg.max = num;
 193                 *flags |= PARAM_MAX;
 194                 break;
 195         case '(':
 196                 if (check_inverse(argv[optind-1], &invert, &optind, 0)) break;
 197                 if (string_to_number(optarg, 0, 0xffffffff, &num) == -1)
 198                         exit_error(PARAMETER_PROBLEM,
 199                                 "bad --hashlimit-htable-gcinterval: `%s'",
 200                                 optarg);
 201                 /* FIXME: not HZ dependent!! */
 202                 r->cfg.gc_interval = num;
 203                 *flags |= PARAM_GCINTERVAL;
 204                 break;
 205         case ')':
 206                 if (check_inverse(argv[optind-1], &invert, &optind, 0)) break;
 207                 if (string_to_number(optarg, 0, 0xffffffff, &num) == -1)
 208                         exit_error(PARAMETER_PROBLEM,
 209                                 "bad --hashlimit-htable-expire: `%s'", optarg);
 210                 /* FIXME: not HZ dependent */
 211                 r->cfg.expire = num;
 212                 *flags |= PARAM_EXPIRE;
 213                 break;
 214         case '_':
 215                 if (check_inverse(argv[optind-1], &invert, &optind, 0)) break;
 216                 if (parse_mode(r, optarg) < 0)
 217                         exit_error(PARAMETER_PROBLEM,
 218                                    "bad --hashlimit-mode: `%s'\n", optarg);
 219                 *flags |= PARAM_MODE;
 220                 break;
 221         case '"':
 222                 if (check_inverse(argv[optind-1], &invert, &optind, 0)) break;
 223                 if (strlen(optarg) == 0)
 224                         exit_error(PARAMETER_PROBLEM, "Zero-length name?");
 225                 strncpy(r->name, optarg, sizeof(r->name));
 226                 *flags |= PARAM_NAME;
 227                 break;
 228         default:
 229                 return 0;
 230         }
 231
 232         if (invert)
 233                 exit_error(PARAMETER_PROBLEM,
 234                            "hashlimit does not support invert");
 235
 236         return 1;
 237 }
 238
 239 /* Final check; nothing. */
 240 static void final_check(unsigned int flags)
 241 {
 242         if (!(flags & PARAM_LIMIT))
 243                 exit_error(PARAMETER_PROBLEM,
 244                                 "You have to specify --hashlimit");
 245         if (!(flags & PARAM_MODE))
 246                 exit_error(PARAMETER_PROBLEM,
 247                                 "You have to specify --hashlimit-mode");
 248         if (!(flags & PARAM_NAME))
 249                 exit_error(PARAMETER_PROBLEM,
 250                                 "You have to specify --hashlimit-name");
 251 }
 252
 253 static struct rates
 254 {
 255         const char *name;
 256         u_int32_t mult;
 257 } rates[] = { { "day", IPT_HASHLIMIT_SCALE*24*60*60 },
 258               { "hour", IPT_HASHLIMIT_SCALE*60*60 },
 259               { "min", IPT_HASHLIMIT_SCALE*60 },
 260               { "sec", IPT_HASHLIMIT_SCALE } };
 261
 262 static void print_rate(u_int32_t period)
 263 {
 264         unsigned int i;
 265
 266         for (i = 1; i < sizeof(rates)/sizeof(struct rates); i++) {
 267                 if (period > rates[i].mult
 268             || rates[i].mult/period < rates[i].mult%period)
 269                         break;
 270         }
 271
 272         printf("%u/%s ", rates[i-1].mult / period, rates[i-1].name);
 273 }
 274
 275 static void print_mode(const struct ipt_hashlimit_info *r, char separator)
 276 {
 277         int prevmode = 0;
 278
 279         if (r->cfg.mode & IPT_HASHLIMIT_HASH_SIP) {
 280                 if (prevmode)
 281                         putchar(separator);
 282                 fputs("srcip", stdout);
 283                 prevmode = 1;
 284         }
 285         if (r->cfg.mode & IPT_HASHLIMIT_HASH_SPT) {
 286                 if (prevmode)
 287                         putchar(separator);
 288                 fputs("srcport", stdout);
 289                 prevmode = 1;
 290         }
 291         if (r->cfg.mode & IPT_HASHLIMIT_HASH_DIP) {
 292                 if (prevmode)
 293                         putchar(separator);
 294                 fputs("dstip", stdout);
 295                 prevmode = 1;
 296         }
 297         if (r->cfg.mode & IPT_HASHLIMIT_HASH_DPT) {
 298                 if (prevmode)
 299                         putchar(separator);
 300                 fputs("dstport", stdout);
 301         }
 302         putchar(' ');
 303 }
 304
 305 /* Prints out the matchinfo. */
 306 static void
 307 print(const struct ipt_ip *ip,
 308       const struct ipt_entry_match *match,
 309       int numeric)
 310 {
 311         struct ipt_hashlimit_info *r =
 312                 (struct ipt_hashlimit_info *)match->data;
 313         fputs("limit: avg ", stdout); print_rate(r->cfg.avg);
 314         printf("burst %u ", r->cfg.burst);
 315         fputs("mode ", stdout);
 316         print_mode(r, '-');
 317         if (r->cfg.size)
 318                 printf("htable-size %u ", r->cfg.size);
 319         if (r->cfg.max)
 320                 printf("htable-max %u ", r->cfg.max);
 321         if (r->cfg.gc_interval != IPT_HASHLIMIT_GCINTERVAL)
 322                 printf("htable-gcinterval %u ", r->cfg.gc_interval);
 323         if (r->cfg.expire != IPT_HASHLIMIT_EXPIRE)
 324                 printf("htable-expire %u ", r->cfg.expire);
 325 }
 326
 327 /* FIXME: Make minimalist: only print rate if not default --RR */
 328 static void save(const struct ipt_ip *ip, const struct ipt_entry_match *match)
 329 {
 330         struct ipt_hashlimit_info *r =
 331                 (struct ipt_hashlimit_info *)match->data;
 332
 333         fputs("--hashlimit ", stdout); print_rate(r->cfg.avg);
 334         if (r->cfg.burst != IPT_HASHLIMIT_BURST)
 335                 printf("--hashlimit-burst %u ", r->cfg.burst);
 336
 337         fputs("--hashlimit-mode ", stdout);
 338         print_mode(r, ',');
 339
 340         printf("--hashlimit-name %s ", r->name);
 341
 342         if (r->cfg.size)
 343                 printf("--hashlimit-htable-size %u ", r->cfg.size);
 344         if (r->cfg.max)
 345                 printf("--hashlimit-htable-max %u ", r->cfg.max);
 346         if (r->cfg.gc_interval != IPT_HASHLIMIT_GCINTERVAL)
 347                 printf("--hashlimit-htable-gcinterval %u", r->cfg.gc_interval);
 348         if (r->cfg.expire != IPT_HASHLIMIT_EXPIRE)
 349                 printf("--hashlimit-htable-expire %u ", r->cfg.expire);
 350 }
 351
 352 static struct iptables_match hashlimit = { NULL,
 353         .name           = "hashlimit",
 354         .version        = IPTABLES_VERSION,
 355         .size           = IPT_ALIGN(sizeof(struct ipt_hashlimit_info)),
 356         .userspacesize  = offsetof(struct ipt_hashlimit_info, hinfo),
 357         .help           = &help,
 358         .init           = &init,
 359         .parse          = &parse,
 360         .final_check    = &final_check,
 361         .print          = &print,
 362         .save           = &save,
 363         .extra_opts     = opts
 364 };
 365
 366 void _init(void)
 367 {
 368         register_match(&hashlimit);
 369 }