extensions/libxt_RATEEST.c

   1 #include <stdio.h>
   2 #include <string.h>
   3 #include <stdlib.h>
   4 #include <stddef.h>
   5 #include <getopt.h>
   6 #include <math.h>
   7
   8 #include <xtables.h>
   9 #include <linux/netfilter/x_tables.h>
  10 #include <linux/netfilter/xt_RATEEST.h>
  11
  12 /* hack to pass raw values to final_check */
  13 static struct xt_rateest_target_info *RATEEST_info;
  14 static unsigned int interval;
  15 static unsigned int ewma_log;
  16
  17 static void
  18 RATEEST_help(void)
  19 {
  20         printf(
  21 "RATEEST target options:\n"
  22 "  --rateest-name name          Rate estimator name\n"
  23 "  --rateest-interval sec       Rate measurement interval in seconds\n"
  24 "  --rateest-ewmalog value      Rate measurement averaging time constant\n");
  25 }
  26
  27 enum RATEEST_options {
  28         RATEEST_OPT_NAME,
  29         RATEEST_OPT_INTERVAL,
  30         RATEEST_OPT_EWMALOG,
  31 };
  32
  33 static const struct option RATEEST_opts[] = {
  34         { "rateest-name",       1, NULL, RATEEST_OPT_NAME },
  35         { "rateest-interval",   1, NULL, RATEEST_OPT_INTERVAL },
  36         { "rateest-ewmalog",    1, NULL, RATEEST_OPT_EWMALOG },
  37         { .name = NULL },
  38 };
  39
  40 /* Copied from iproute */
  41 #define TIME_UNITS_PER_SEC      1000000
  42
  43 static int
  44 RATEEST_get_time(unsigned int *time, const char *str)
  45 {
  46         double t;
  47         char *p;
  48
  49         t = strtod(str, &p);
  50         if (p == str)
  51                 return -1;
  52
  53         if (*p) {
  54                 if (strcasecmp(p, "s") == 0 || strcasecmp(p, "sec")==0 ||
  55                     strcasecmp(p, "secs")==0)
  56                         t *= TIME_UNITS_PER_SEC;
  57                 else if (strcasecmp(p, "ms") == 0 || strcasecmp(p, "msec")==0 ||
  58                          strcasecmp(p, "msecs") == 0)
  59                         t *= TIME_UNITS_PER_SEC/1000;
  60                 else if (strcasecmp(p, "us") == 0 || strcasecmp(p, "usec")==0 ||
  61                          strcasecmp(p, "usecs") == 0)
  62                         t *= TIME_UNITS_PER_SEC/1000000;
  63                 else
  64                         return -1;
  65         }
  66
  67         *time = t;
  68         return 0;
  69 }
  70
  71 static void
  72 RATEEST_print_time(unsigned int time)
  73 {
  74         double tmp = time;
  75
  76         if (tmp >= TIME_UNITS_PER_SEC)
  77                 printf("%.1fs ", tmp/TIME_UNITS_PER_SEC);
  78         else if (tmp >= TIME_UNITS_PER_SEC/1000)
  79                 printf("%.1fms ", tmp/(TIME_UNITS_PER_SEC/1000));
  80         else
  81                 printf("%uus ", time);
  82 }
  83
  84 static void
  85 RATEEST_init(struct xt_entry_target *target)
  86 {
  87         interval = 0;
  88         ewma_log = 0;
  89 }
  90
  91 static int
  92 RATEEST_parse(int c, char **argv, int invert, unsigned int *flags,
  93               const void *entry, struct xt_entry_target **target)
  94 {
  95         struct xt_rateest_target_info *info = (void *)(*target)->data;
  96
  97         RATEEST_info = info;
  98
  99         switch (c) {
 100         case RATEEST_OPT_NAME:
 101                 if (*flags & (1 << c))
 102                         xtables_error(PARAMETER_PROBLEM,
 103                                    "RATEEST: can't specify --rateest-name twice");
 104                 *flags |= 1 << c;
 105
 106                 strncpy(info->name, optarg, sizeof(info->name) - 1);
 107                 break;
 108
 109         case RATEEST_OPT_INTERVAL:
 110                 if (*flags & (1 << c))
 111                         xtables_error(PARAMETER_PROBLEM,
 112                                    "RATEEST: can't specify --rateest-interval twice");
 113                 *flags |= 1 << c;
 114
 115                 if (RATEEST_get_time(&interval, optarg) < 0)
 116                         xtables_error(PARAMETER_PROBLEM,
 117                                    "RATEEST: bad interval value `%s'", optarg);
 118
 119                 break;
 120
 121         case RATEEST_OPT_EWMALOG:
 122                 if (*flags & (1 << c))
 123                         xtables_error(PARAMETER_PROBLEM,
 124                                    "RATEEST: can't specify --rateest-ewmalog twice");
 125                 *flags |= 1 << c;
 126
 127                 if (RATEEST_get_time(&ewma_log, optarg) < 0)
 128                         xtables_error(PARAMETER_PROBLEM,
 129                                    "RATEEST: bad ewmalog value `%s'", optarg);
 130
 131                 break;
 132
 133         default:
 134                 return 0;
 135         }
 136
 137         return 1;
 138 }
 139
 140 static void
 141 RATEEST_final_check(unsigned int flags)
 142 {
 143         struct xt_rateest_target_info *info = RATEEST_info;
 144
 145         if (!(flags & (1 << RATEEST_OPT_NAME)))
 146                 xtables_error(PARAMETER_PROBLEM, "RATEEST: no name specified");
 147         if (!(flags & (1 << RATEEST_OPT_INTERVAL)))
 148                 xtables_error(PARAMETER_PROBLEM, "RATEEST: no interval specified");
 149         if (!(flags & (1 << RATEEST_OPT_EWMALOG)))
 150                 xtables_error(PARAMETER_PROBLEM, "RATEEST: no ewmalog specified");
 151
 152         for (info->interval = 0; info->interval <= 5; info->interval++) {
 153                 if (interval <= (1 << info->interval) * (TIME_UNITS_PER_SEC / 4))
 154                         break;
 155         }
 156
 157         if (info->interval > 5)
 158                 xtables_error(PARAMETER_PROBLEM,
 159                            "RATEEST: interval value is too large");
 160         info->interval -= 2;
 161
 162         for (info->ewma_log = 1; info->ewma_log < 32; info->ewma_log++) {
 163                 double w = 1.0 - 1.0 / (1 << info->ewma_log);
 164                 if (interval / (-log(w)) > ewma_log)
 165                         break;
 166         }
 167         info->ewma_log--;
 168
 169         if (info->ewma_log == 0 || info->ewma_log >= 31)
 170                 xtables_error(PARAMETER_PROBLEM,
 171                            "RATEEST: ewmalog value is out of range");
 172 }
 173
 174 static void
 175 __RATEEST_print(const struct xt_entry_target *target, const char *prefix)
 176 {
 177         const struct xt_rateest_target_info *info = (const void *)target->data;
 178         unsigned int local_interval;
 179         unsigned int local_ewma_log;
 180
 181         local_interval = (TIME_UNITS_PER_SEC << (info->interval + 2)) / 4;
 182         local_ewma_log = local_interval * (1 << (info->ewma_log));
 183
 184         printf("%sname %s ", prefix, info->name);
 185         printf("%sinterval ", prefix);
 186         RATEEST_print_time(local_interval);
 187         printf("%sewmalog ", prefix);
 188         RATEEST_print_time(local_ewma_log);
 189 }
 190
 191 static void
 192 RATEEST_print(const void *ip, const struct xt_entry_target *target,
 193               int numeric)
 194 {
 195         __RATEEST_print(target, "");
 196 }
 197
 198 static void
 199 RATEEST_save(const void *ip, const struct xt_entry_target *target)
 200 {
 201         __RATEEST_print(target, "--rateest-");
 202 }
 203
 204 static struct xtables_target rateest_tg_reg = {
 205         .family         = AF_UNSPEC,
 206         .name           = "RATEEST",
 207         .version        = XTABLES_VERSION,
 208         .size           = XT_ALIGN(sizeof(struct xt_rateest_target_info)),
 209         .userspacesize  = XT_ALIGN(sizeof(struct xt_rateest_target_info)),
 210         .help           = RATEEST_help,
 211         .init           = RATEEST_init,
 212         .parse          = RATEEST_parse,
 213         .final_check    = RATEEST_final_check,
 214         .print          = RATEEST_print,
 215         .save           = RATEEST_save,
 216         .extra_opts     = RATEEST_opts,
 217 };
 218
 219 void _init(void)
 220 {
 221         xtables_register_target(&rateest_tg_reg);
 222 }