LXR linux/net/netfilter/xt

   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, 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
  77static 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
 114err2:
 115        xt_rateest_put(est1);
 116err1:
 117        return false;
 118}
 119
 120static 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
 129static 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
 140static int __init xt_rateest_mt_init(void)
 141{
 142        return xt_register_match(&xt_rateest_mt_reg);
 143}
 144
 145static void __exit xt_rateest_mt_fini(void)
 146{
 147        xt_unregister_match(&xt_rateest_mt_reg);
 148}
 149
 150MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 151MODULE_LICENSE("GPL");
 152MODULE_DESCRIPTION("xtables rate estimator match");
 153MODULE_ALIAS("ipt_rateest");
 154MODULE_ALIAS("ip6t_rateest");
 155module_init(xt_rateest_mt_init);
 156module_exit(xt_rateest_mt_fini);
 157