linux/net/netfilter/xt_RATEEST.c
<<
>>
Prefs
   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#include <linux/jhash.h>
  12#include <linux/rtnetlink.h>
  13#include <linux/random.h>
  14#include <linux/slab.h>
  15#include <net/gen_stats.h>
  16#include <net/netlink.h>
  17
  18#include <linux/netfilter/x_tables.h>
  19#include <linux/netfilter/xt_RATEEST.h>
  20#include <net/netfilter/xt_rateest.h>
  21
  22static DEFINE_MUTEX(xt_rateest_mutex);
  23
  24#define RATEEST_HSIZE   16
  25static struct hlist_head rateest_hash[RATEEST_HSIZE] __read_mostly;
  26static unsigned int jhash_rnd __read_mostly;
  27static bool rnd_inited __read_mostly;
  28
  29static unsigned int xt_rateest_hash(const char *name)
  30{
  31        return jhash(name, FIELD_SIZEOF(struct xt_rateest, name), jhash_rnd) &
  32               (RATEEST_HSIZE - 1);
  33}
  34
  35static void xt_rateest_hash_insert(struct xt_rateest *est)
  36{
  37        unsigned int h;
  38
  39        h = xt_rateest_hash(est->name);
  40        hlist_add_head(&est->list, &rateest_hash[h]);
  41}
  42
  43struct xt_rateest *xt_rateest_lookup(const char *name)
  44{
  45        struct xt_rateest *est;
  46        struct hlist_node *n;
  47        unsigned int h;
  48
  49        h = xt_rateest_hash(name);
  50        mutex_lock(&xt_rateest_mutex);
  51        hlist_for_each_entry(est, n, &rateest_hash[h], list) {
  52                if (strcmp(est->name, name) == 0) {
  53                        est->refcnt++;
  54                        mutex_unlock(&xt_rateest_mutex);
  55                        return est;
  56                }
  57        }
  58        mutex_unlock(&xt_rateest_mutex);
  59        return NULL;
  60}
  61EXPORT_SYMBOL_GPL(xt_rateest_lookup);
  62
  63void xt_rateest_put(struct xt_rateest *est)
  64{
  65        mutex_lock(&xt_rateest_mutex);
  66        if (--est->refcnt == 0) {
  67                hlist_del(&est->list);
  68                gen_kill_estimator(&est->bstats, &est->rstats);
  69                /*
  70                 * gen_estimator est_timer() might access est->lock or bstats,
  71                 * wait a RCU grace period before freeing 'est'
  72                 */
  73                kfree_rcu(est, rcu);
  74        }
  75        mutex_unlock(&xt_rateest_mutex);
  76}
  77EXPORT_SYMBOL_GPL(xt_rateest_put);
  78
  79static unsigned int
  80xt_rateest_tg(struct sk_buff *skb, const struct xt_action_param *par)
  81{
  82        const struct xt_rateest_target_info *info = par->targinfo;
  83        struct gnet_stats_basic_packed *stats = &info->est->bstats;
  84
  85        spin_lock_bh(&info->est->lock);
  86        stats->bytes += skb->len;
  87        stats->packets++;
  88        spin_unlock_bh(&info->est->lock);
  89
  90        return XT_CONTINUE;
  91}
  92
  93static int xt_rateest_tg_checkentry(const struct xt_tgchk_param *par)
  94{
  95        struct xt_rateest_target_info *info = par->targinfo;
  96        struct xt_rateest *est;
  97        struct {
  98                struct nlattr           opt;
  99                struct gnet_estimator   est;
 100        } cfg;
 101        int ret;
 102
 103        if (unlikely(!rnd_inited)) {
 104                get_random_bytes(&jhash_rnd, sizeof(jhash_rnd));
 105                rnd_inited = true;
 106        }
 107
 108        est = xt_rateest_lookup(info->name);
 109        if (est) {
 110                /*
 111                 * If estimator parameters are specified, they must match the
 112                 * existing estimator.
 113                 */
 114                if ((!info->interval && !info->ewma_log) ||
 115                    (info->interval != est->params.interval ||
 116                     info->ewma_log != est->params.ewma_log)) {
 117                        xt_rateest_put(est);
 118                        return -EINVAL;
 119                }
 120                info->est = est;
 121                return 0;
 122        }
 123
 124        ret = -ENOMEM;
 125        est = kzalloc(sizeof(*est), GFP_KERNEL);
 126        if (!est)
 127                goto err1;
 128
 129        strlcpy(est->name, info->name, sizeof(est->name));
 130        spin_lock_init(&est->lock);
 131        est->refcnt             = 1;
 132        est->params.interval    = info->interval;
 133        est->params.ewma_log    = info->ewma_log;
 134
 135        cfg.opt.nla_len         = nla_attr_size(sizeof(cfg.est));
 136        cfg.opt.nla_type        = TCA_STATS_RATE_EST;
 137        cfg.est.interval        = info->interval;
 138        cfg.est.ewma_log        = info->ewma_log;
 139
 140        ret = gen_new_estimator(&est->bstats, &est->rstats,
 141                                &est->lock, &cfg.opt);
 142        if (ret < 0)
 143                goto err2;
 144
 145        info->est = est;
 146        xt_rateest_hash_insert(est);
 147        return 0;
 148
 149err2:
 150        kfree(est);
 151err1:
 152        return ret;
 153}
 154
 155static void xt_rateest_tg_destroy(const struct xt_tgdtor_param *par)
 156{
 157        struct xt_rateest_target_info *info = par->targinfo;
 158
 159        xt_rateest_put(info->est);
 160}
 161
 162static struct xt_target xt_rateest_tg_reg __read_mostly = {
 163        .name       = "RATEEST",
 164        .revision   = 0,
 165        .family     = NFPROTO_UNSPEC,
 166        .target     = xt_rateest_tg,
 167        .checkentry = xt_rateest_tg_checkentry,
 168        .destroy    = xt_rateest_tg_destroy,
 169        .targetsize = sizeof(struct xt_rateest_target_info),
 170        .me         = THIS_MODULE,
 171};
 172
 173static int __init xt_rateest_tg_init(void)
 174{
 175        unsigned int i;
 176
 177        for (i = 0; i < ARRAY_SIZE(rateest_hash); i++)
 178                INIT_HLIST_HEAD(&rateest_hash[i]);
 179
 180        return xt_register_target(&xt_rateest_tg_reg);
 181}
 182
 183static void __exit xt_rateest_tg_fini(void)
 184{
 185        xt_unregister_target(&xt_rateest_tg_reg);
 186}
 187
 188
 189MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 190MODULE_LICENSE("GPL");
 191MODULE_DESCRIPTION("Xtables: packet rate estimator");
 192MODULE_ALIAS("ipt_RATEEST");
 193MODULE_ALIAS("ip6t_RATEEST");
 194module_init(xt_rateest_tg_init);
 195module_exit(xt_rateest_tg_fini);
 196
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.