linux/net/netfilter/xt_rateest.c
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   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
  17static bool
  18xt_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
  77static 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
 115err2:
 116        xt_rateest_put(est1);
 117err1:
 118        return ret;
 119}
 120
 121static 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
 130static 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
 141static int __init xt_rateest_mt_init(void)
 142{
 143        return xt_register_match(&xt_rateest_mt_reg);
 144}
 145
 146static void __exit xt_rateest_mt_fini(void)
 147{
 148        xt_unregister_match(&xt_rateest_mt_reg);
 149}
 150
 151MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 152MODULE_LICENSE("GPL");
 153MODULE_DESCRIPTION("xtables rate estimator match");
 154MODULE_ALIAS("ipt_rateest");
 155MODULE_ALIAS("ip6t_rateest");
 156module_init(xt_rateest_mt_init);
 157module_exit(xt_rateest_mt_fini);
 158
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