net/netfilter/xt_rateest.c

   1 /*
   2  * (C) 2007 Patrick McHardy <kaber@trash.net>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  */
   8 #include <linux/module.h>
   9 #include <linux/skbuff.h>
  10 #include <linux/gen_stats.h>
  11
  12 #include <linux/netfilter/x_tables.h>
  13 #include <linux/netfilter/xt_rateest.h>
  14 #include <net/netfilter/xt_rateest.h>
  15
  16
  17 static bool
  18 xt_rateest_mt(const struct sk_buff *skb, const struct xt_match_param *par)
  19 {
  20         const struct xt_rateest_match_info *info = par->matchinfo;
  21         struct gnet_stats_rate_est *r;
  22         u_int32_t bps1, bps2, pps1, pps2;
  23         bool ret = true;
  24
  25         spin_lock_bh(&info->est1->lock);
  26         r = &info->est1->rstats;
  27         if (info->flags & XT_RATEEST_MATCH_DELTA) {
  28                 bps1 = info->bps1 >= r->bps ? info->bps1 - r->bps : 0;
  29                 pps1 = info->pps1 >= r->pps ? info->pps1 - r->pps : 0;
  30         } else {
  31                 bps1 = r->bps;
  32                 pps1 = r->pps;
  33         }
  34         spin_unlock_bh(&info->est1->lock);
  35
  36         if (info->flags & XT_RATEEST_MATCH_ABS) {
  37                 bps2 = info->bps2;
  38                 pps2 = info->pps2;
  39         } else {
  40                 spin_lock_bh(&info->est2->lock);
  41                 r = &info->est2->rstats;
  42                 if (info->flags & XT_RATEEST_MATCH_DELTA) {
  43                         bps2 = info->bps2 >= r->bps ? info->bps2 - r->bps : 0;
  44                         pps2 = info->pps2 >= r->pps ? info->pps2 - r->pps : 0;
  45                 } else {
  46                         bps2 = r->bps;
  47                         pps2 = r->pps;
  48                 }
  49                 spin_unlock_bh(&info->est2->lock);
  50         }
  51
  52         switch (info->mode) {
  53         case XT_RATEEST_MATCH_LT:
  54                 if (info->flags & XT_RATEEST_MATCH_BPS)
  55                         ret &= bps1 < bps2;
  56                 if (info->flags & XT_RATEEST_MATCH_PPS)
  57                         ret &= pps1 < pps2;
  58                 break;
  59         case XT_RATEEST_MATCH_GT:
  60                 if (info->flags & XT_RATEEST_MATCH_BPS)
  61                         ret &= bps1 > bps2;
  62                 if (info->flags & XT_RATEEST_MATCH_PPS)
  63                         ret &= pps1 > pps2;
  64                 break;
  65         case XT_RATEEST_MATCH_EQ:
  66                 if (info->flags & XT_RATEEST_MATCH_BPS)
  67                         ret &= bps1 == bps2;
  68                 if (info->flags & XT_RATEEST_MATCH_PPS)
  69                         ret &= pps1 == pps2;
  70                 break;
  71         }
  72
  73         ret ^= info->flags & XT_RATEEST_MATCH_INVERT ? true : false;
  74         return ret;
  75 }
  76
  77 static bool xt_rateest_mt_checkentry(const struct xt_mtchk_param *par)
  78 {
  79         struct xt_rateest_match_info *info = par->matchinfo;
  80         struct xt_rateest *est1, *est2;
  81
  82         if (hweight32(info->flags & (XT_RATEEST_MATCH_ABS |
  83                                      XT_RATEEST_MATCH_REL)) != 1)
  84                 goto err1;
  85
  86         if (!(info->flags & (XT_RATEEST_MATCH_BPS | XT_RATEEST_MATCH_PPS)))
  87                 goto err1;
  88
  89         switch (info->mode) {
  90         case XT_RATEEST_MATCH_EQ:
  91         case XT_RATEEST_MATCH_LT:
  92         case XT_RATEEST_MATCH_GT:
  93                 break;
  94         default:
  95                 goto err1;
  96         }
  97
  98         est1 = xt_rateest_lookup(info->name1);
  99         if (!est1)
 100                 goto err1;
 101
 102         if (info->flags & XT_RATEEST_MATCH_REL) {
 103                 est2 = xt_rateest_lookup(info->name2);
 104                 if (!est2)
 105                         goto err2;
 106         } else
 107                 est2 = NULL;
 108
 109
 110         info->est1 = est1;
 111         info->est2 = est2;
 112         return true;
 113
 114 err2:
 115         xt_rateest_put(est1);
 116 err1:
 117         return false;
 118 }
 119
 120 static void xt_rateest_mt_destroy(const struct xt_mtdtor_param *par)
 121 {
 122         struct xt_rateest_match_info *info = par->matchinfo;
 123
 124         xt_rateest_put(info->est1);
 125         if (info->est2)
 126                 xt_rateest_put(info->est2);
 127 }
 128
 129 static struct xt_match xt_rateest_mt_reg __read_mostly = {
 130         .name       = "rateest",
 131         .revision   = 0,
 132         .family     = NFPROTO_UNSPEC,
 133         .match      = xt_rateest_mt,
 134         .checkentry = xt_rateest_mt_checkentry,
 135         .destroy    = xt_rateest_mt_destroy,
 136         .matchsize  = sizeof(struct xt_rateest_match_info),
 137         .me         = THIS_MODULE,
 138 };
 139
 140 static int __init xt_rateest_mt_init(void)
 141 {
 142         return xt_register_match(&xt_rateest_mt_reg);
 143 }
 144
 145 static void __exit xt_rateest_mt_fini(void)
 146 {
 147         xt_unregister_match(&xt_rateest_mt_reg);
 148 }
 149
 150 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 151 MODULE_LICENSE("GPL");
 152 MODULE_DESCRIPTION("xtables rate estimator match");
 153 MODULE_ALIAS("ipt_rateest");
 154 MODULE_ALIAS("ip6t_rateest");
 155 module_init(xt_rateest_mt_init);
 156 module_exit(xt_rateest_mt_fini);