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, struct xt_action_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 int 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         int ret = -EINVAL;
  82
  83         if (hweight32(info->flags & (XT_RATEEST_MATCH_ABS |
  84                                      XT_RATEEST_MATCH_REL)) != 1)
  85                 goto err1;
  86
  87         if (!(info->flags & (XT_RATEEST_MATCH_BPS | XT_RATEEST_MATCH_PPS)))
  88                 goto err1;
  89
  90         switch (info->mode) {
  91         case XT_RATEEST_MATCH_EQ:
  92         case XT_RATEEST_MATCH_LT:
  93         case XT_RATEEST_MATCH_GT:
  94                 break;
  95         default:
  96                 goto err1;
  97         }
  98
  99         ret  = -ENOENT;
 100         est1 = xt_rateest_lookup(info->name1);
 101         if (!est1)
 102                 goto err1;
 103
 104         est2 = NULL;
 105         if (info->flags & XT_RATEEST_MATCH_REL) {
 106                 est2 = xt_rateest_lookup(info->name2);
 107                 if (!est2)
 108                         goto err2;
 109         }
 110
 111         info->est1 = est1;
 112         info->est2 = est2;
 113         return 0;
 114
 115 err2:
 116         xt_rateest_put(est1);
 117 err1:
 118         return ret;
 119 }
 120
 121 static void xt_rateest_mt_destroy(const struct xt_mtdtor_param *par)
 122 {
 123         struct xt_rateest_match_info *info = par->matchinfo;
 124
 125         xt_rateest_put(info->est1);
 126         if (info->est2)
 127                 xt_rateest_put(info->est2);
 128 }
 129
 130 static struct xt_match xt_rateest_mt_reg __read_mostly = {
 131         .name       = "rateest",
 132         .revision   = 0,
 133         .family     = NFPROTO_UNSPEC,
 134         .match      = xt_rateest_mt,
 135         .checkentry = xt_rateest_mt_checkentry,
 136         .destroy    = xt_rateest_mt_destroy,
 137         .matchsize  = sizeof(struct xt_rateest_match_info),
 138         .me         = THIS_MODULE,
 139 };
 140
 141 static int __init xt_rateest_mt_init(void)
 142 {
 143         return xt_register_match(&xt_rateest_mt_reg);
 144 }
 145
 146 static void __exit xt_rateest_mt_fini(void)
 147 {
 148         xt_unregister_match(&xt_rateest_mt_reg);
 149 }
 150
 151 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 152 MODULE_LICENSE("GPL");
 153 MODULE_DESCRIPTION("xtables rate estimator match");
 154 MODULE_ALIAS("ipt_rateest");
 155 MODULE_ALIAS("ip6t_rateest");
 156 module_init(xt_rateest_mt_init);
 157 module_exit(xt_rateest_mt_fini);