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 xt_rateest_mt(const struct sk_buff *skb,
  18                           const struct net_device *in,
  19                           const struct net_device *out,
  20                           const struct xt_match *match,
  21                           const void *matchinfo,
  22                           int offset,
  23                           unsigned int protoff,
  24                           bool *hotdrop)
  25 {
  26         const struct xt_rateest_match_info *info = matchinfo;
  27         struct gnet_stats_rate_est *r;
  28         u_int32_t bps1, bps2, pps1, pps2;
  29         bool ret = true;
  30
  31         spin_lock_bh(&info->est1->lock);
  32         r = &info->est1->rstats;
  33         if (info->flags & XT_RATEEST_MATCH_DELTA) {
  34                 bps1 = info->bps1 >= r->bps ? info->bps1 - r->bps : 0;
  35                 pps1 = info->pps1 >= r->pps ? info->pps1 - r->pps : 0;
  36         } else {
  37                 bps1 = r->bps;
  38                 pps1 = r->pps;
  39         }
  40         spin_unlock_bh(&info->est1->lock);
  41
  42         if (info->flags & XT_RATEEST_MATCH_ABS) {
  43                 bps2 = info->bps2;
  44                 pps2 = info->pps2;
  45         } else {
  46                 spin_lock_bh(&info->est2->lock);
  47                 r = &info->est2->rstats;
  48                 if (info->flags & XT_RATEEST_MATCH_DELTA) {
  49                         bps2 = info->bps2 >= r->bps ? info->bps2 - r->bps : 0;
  50                         pps2 = info->pps2 >= r->pps ? info->pps2 - r->pps : 0;
  51                 } else {
  52                         bps2 = r->bps;
  53                         pps2 = r->pps;
  54                 }
  55                 spin_unlock_bh(&info->est2->lock);
  56         }
  57
  58         switch (info->mode) {
  59         case XT_RATEEST_MATCH_LT:
  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_GT:
  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         case XT_RATEEST_MATCH_EQ:
  72                 if (info->flags & XT_RATEEST_MATCH_BPS)
  73                         ret &= bps1 == bps2;
  74                 if (info->flags & XT_RATEEST_MATCH_PPS)
  75                         ret &= pps2 == pps2;
  76                 break;
  77         }
  78
  79         ret ^= info->flags & XT_RATEEST_MATCH_INVERT ? true : false;
  80         return ret;
  81 }
  82
  83 static bool xt_rateest_mt_checkentry(const char *tablename,
  84                                      const void *ip,
  85                                      const struct xt_match *match,
  86                                      void *matchinfo,
  87                                      unsigned int hook_mask)
  88 {
  89         struct xt_rateest_match_info *info = matchinfo;
  90         struct xt_rateest *est1, *est2;
  91
  92         if (hweight32(info->flags & (XT_RATEEST_MATCH_ABS |
  93                                      XT_RATEEST_MATCH_REL)) != 1)
  94                 goto err1;
  95
  96         if (!(info->flags & (XT_RATEEST_MATCH_BPS | XT_RATEEST_MATCH_PPS)))
  97                 goto err1;
  98
  99         switch (info->mode) {
 100         case XT_RATEEST_MATCH_EQ:
 101         case XT_RATEEST_MATCH_LT:
 102         case XT_RATEEST_MATCH_GT:
 103                 break;
 104         default:
 105                 goto err1;
 106         }
 107
 108         est1 = xt_rateest_lookup(info->name1);
 109         if (!est1)
 110                 goto err1;
 111
 112         if (info->flags & XT_RATEEST_MATCH_REL) {
 113                 est2 = xt_rateest_lookup(info->name2);
 114                 if (!est2)
 115                         goto err2;
 116         } else
 117                 est2 = NULL;
 118
 119
 120         info->est1 = est1;
 121         info->est2 = est2;
 122         return true;
 123
 124 err2:
 125         xt_rateest_put(est1);
 126 err1:
 127         return false;
 128 }
 129
 130 static void xt_rateest_mt_destroy(const struct xt_match *match,
 131                                   void *matchinfo)
 132 {
 133         struct xt_rateest_match_info *info = matchinfo;
 134
 135         xt_rateest_put(info->est1);
 136         if (info->est2)
 137                 xt_rateest_put(info->est2);
 138 }
 139
 140 static struct xt_match xt_rateest_match[] __read_mostly = {
 141         {
 142                 .family         = AF_INET,
 143                 .name           = "rateest",
 144                 .match          = xt_rateest_mt,
 145                 .checkentry     = xt_rateest_mt_checkentry,
 146                 .destroy        = xt_rateest_mt_destroy,
 147                 .matchsize      = sizeof(struct xt_rateest_match_info),
 148                 .me             = THIS_MODULE,
 149         },
 150         {
 151                 .family         = AF_INET6,
 152                 .name           = "rateest",
 153                 .match          = xt_rateest_mt,
 154                 .checkentry     = xt_rateest_mt_checkentry,
 155                 .destroy        = xt_rateest_mt_destroy,
 156                 .matchsize      = sizeof(struct xt_rateest_match_info),
 157                 .me             = THIS_MODULE,
 158         },
 159 };
 160
 161 static int __init xt_rateest_mt_init(void)
 162 {
 163         return xt_register_matches(xt_rateest_match,
 164                                    ARRAY_SIZE(xt_rateest_match));
 165 }
 166
 167 static void __exit xt_rateest_mt_fini(void)
 168 {
 169         xt_unregister_matches(xt_rateest_match, ARRAY_SIZE(xt_rateest_match));
 170 }
 171
 172 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 173 MODULE_LICENSE("GPL");
 174 MODULE_DESCRIPTION("xtables rate estimator match");
 175 MODULE_ALIAS("ipt_rateest");
 176 MODULE_ALIAS("ip6t_rateest");
 177 module_init(xt_rateest_mt_init);
 178 module_exit(xt_rateest_mt_fini);