xt_rateest.c

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/*
 * (C) 2007 Patrick McHardy <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/gen_stats.h>

#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_rateest.h>
#include <net/netfilter/xt_rateest.h>


static bool
xt_rateest_mt(const struct sk_buff *skb, struct xt_action_param *par)
{
    const struct xt_rateest_match_info *info = par->matchinfo;
    struct gnet_stats_rate_est *r;
    u_int32_t bps1, bps2, pps1, pps2;
    bool ret = true;

    spin_lock_bh(&info->est1->lock);
    r = &info->est1->rstats;
    if (info->flags & XT_RATEEST_MATCH_DELTA) {
        bps1 = info->bps1 >= r->bps ? info->bps1 - r->bps : 0;
        pps1 = info->pps1 >= r->pps ? info->pps1 - r->pps : 0;
    } else {
        bps1 = r->bps;
        pps1 = r->pps;
    }
    spin_unlock_bh(&info->est1->lock);

    if (info->flags & XT_RATEEST_MATCH_ABS) {
        bps2 = info->bps2;
        pps2 = info->pps2;
    } else {
        spin_lock_bh(&info->est2->lock);
        r = &info->est2->rstats;
        if (info->flags & XT_RATEEST_MATCH_DELTA) {
            bps2 = info->bps2 >= r->bps ? info->bps2 - r->bps : 0;
            pps2 = info->pps2 >= r->pps ? info->pps2 - r->pps : 0;
        } else {
            bps2 = r->bps;
            pps2 = r->pps;
        }
        spin_unlock_bh(&info->est2->lock);
    }

    switch (info->mode) {
    case XT_RATEEST_MATCH_LT:
        if (info->flags & XT_RATEEST_MATCH_BPS)
            ret &= bps1 < bps2;
        if (info->flags & XT_RATEEST_MATCH_PPS)
            ret &= pps1 < pps2;
        break;
    case XT_RATEEST_MATCH_GT:
        if (info->flags & XT_RATEEST_MATCH_BPS)
            ret &= bps1 > bps2;
        if (info->flags & XT_RATEEST_MATCH_PPS)
            ret &= pps1 > pps2;
        break;
    case XT_RATEEST_MATCH_EQ:
        if (info->flags & XT_RATEEST_MATCH_BPS)
            ret &= bps1 == bps2;
        if (info->flags & XT_RATEEST_MATCH_PPS)
            ret &= pps1 == pps2;
        break;
    }

    ret ^= info->flags & XT_RATEEST_MATCH_INVERT ? true : false;
    return ret;
}

static int xt_rateest_mt_checkentry(const struct xt_mtchk_param *par)
{
    struct xt_rateest_match_info *info = par->matchinfo;
    struct xt_rateest *est1, *est2;
    int ret = -EINVAL;

    if (hweight32(info->flags & (XT_RATEEST_MATCH_ABS |
                     XT_RATEEST_MATCH_REL)) != 1)
        goto err1;

    if (!(info->flags & (XT_RATEEST_MATCH_BPS | XT_RATEEST_MATCH_PPS)))
        goto err1;

    switch (info->mode) {
    case XT_RATEEST_MATCH_EQ:
    case XT_RATEEST_MATCH_LT:
    case XT_RATEEST_MATCH_GT:
        break;
    default:
        goto err1;
    }

    ret  = -ENOENT;
    est1 = xt_rateest_lookup(info->name1);
    if (!est1)
        goto err1;

    est2 = NULL;
    if (info->flags & XT_RATEEST_MATCH_REL) {
        est2 = xt_rateest_lookup(info->name2);
        if (!est2)
            goto err2;
    }

    info->est1 = est1;
    info->est2 = est2;
    return 0;

err2:
    xt_rateest_put(est1);
err1:
    return ret;
}

static void xt_rateest_mt_destroy(const struct xt_mtdtor_param *par)
{
    struct xt_rateest_match_info *info = par->matchinfo;

    xt_rateest_put(info->est1);
    if (info->est2)
        xt_rateest_put(info->est2);
}

static struct xt_match xt_rateest_mt_reg __read_mostly = {
    .name       = "rateest",
    .revision   = 0,
    .family     = NFPROTO_UNSPEC,
    .match      = xt_rateest_mt,
    .checkentry = xt_rateest_mt_checkentry,
    .destroy    = xt_rateest_mt_destroy,
    .matchsize  = sizeof(struct xt_rateest_match_info),
    .me         = THIS_MODULE,
};

static int __init xt_rateest_mt_init(void)
{
    return xt_register_match(&xt_rateest_mt_reg);
}

static void __exit xt_rateest_mt_fini(void)
{
    xt_unregister_match(&xt_rateest_mt_reg);
}

MODULE_AUTHOR("Patrick McHardy <[email protected]>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("xtables rate estimator match");
MODULE_ALIAS("ipt_rateest");
MODULE_ALIAS("ip6t_rateest");
module_init(xt_rateest_mt_init);
module_exit(xt_rateest_mt_fini);