diff options
Diffstat (limited to 'net/netfilter/xt_limit.c')
| -rw-r--r-- | net/netfilter/xt_limit.c | 68 |
1 files changed, 44 insertions, 24 deletions
diff --git a/net/netfilter/xt_limit.c b/net/netfilter/xt_limit.c index c908d69a559..bef85059655 100644 --- a/net/netfilter/xt_limit.c +++ b/net/netfilter/xt_limit.c @@ -1,11 +1,14 @@ /* (C) 1999 Jérôme de Vivie <devivie@info.enserb.u-bordeaux.fr> * (C) 1999 Hervé Eychenne <eychenne@info.enserb.u-bordeaux.fr> + * (C) 2006-2012 Patrick McHardy <kaber@trash.net> * * 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. */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#include <linux/slab.h> #include <linux/module.h> #include <linux/skbuff.h> #include <linux/spinlock.h> @@ -14,6 +17,11 @@ #include <linux/netfilter/x_tables.h> #include <linux/netfilter/xt_limit.h> +struct xt_limit_priv { + unsigned long prev; + uint32_t credit; +}; + MODULE_LICENSE("GPL"); MODULE_AUTHOR("Herve Eychenne <rv@wallfire.org>"); MODULE_DESCRIPTION("Xtables: rate-limit match"); @@ -58,20 +66,20 @@ static DEFINE_SPINLOCK(limit_lock); #define CREDITS_PER_JIFFY POW2_BELOW32(MAX_CPJ) static bool -limit_mt(const struct sk_buff *skb, const struct xt_match_param *par) +limit_mt(const struct sk_buff *skb, struct xt_action_param *par) { - struct xt_rateinfo *r = - ((const struct xt_rateinfo *)par->matchinfo)->master; + const struct xt_rateinfo *r = par->matchinfo; + struct xt_limit_priv *priv = r->master; unsigned long now = jiffies; spin_lock_bh(&limit_lock); - r->credit += (now - xchg(&r->prev, now)) * CREDITS_PER_JIFFY; - if (r->credit > r->credit_cap) - r->credit = r->credit_cap; + priv->credit += (now - xchg(&priv->prev, now)) * CREDITS_PER_JIFFY; + if (priv->credit > r->credit_cap) + priv->credit = r->credit_cap; - if (r->credit >= r->cost) { + if (priv->credit >= r->cost) { /* We're not limited. */ - r->credit -= r->cost; + priv->credit -= r->cost; spin_unlock_bh(&limit_lock); return true; } @@ -81,8 +89,7 @@ limit_mt(const struct sk_buff *skb, const struct xt_match_param *par) } /* Precision saver. */ -static u_int32_t -user2credits(u_int32_t user) +static u32 user2credits(u32 user) { /* If multiplying would overflow... */ if (user > 0xFFFFFFFF / (HZ*CREDITS_PER_JIFFY)) @@ -92,29 +99,41 @@ user2credits(u_int32_t user) return (user * HZ * CREDITS_PER_JIFFY) / XT_LIMIT_SCALE; } -static bool limit_mt_check(const struct xt_mtchk_param *par) +static int limit_mt_check(const struct xt_mtchk_param *par) { struct xt_rateinfo *r = par->matchinfo; + struct xt_limit_priv *priv; /* Check for overflow. */ if (r->burst == 0 || user2credits(r->avg * r->burst) < user2credits(r->avg)) { - printk("Overflow in xt_limit, try lower: %u/%u\n", - r->avg, r->burst); - return false; + pr_info("Overflow, try lower: %u/%u\n", + r->avg, r->burst); + return -ERANGE; } - /* For SMP, we only want to use one set of counters. */ - r->master = r; + priv = kmalloc(sizeof(*priv), GFP_KERNEL); + if (priv == NULL) + return -ENOMEM; + + /* For SMP, we only want to use one set of state. */ + r->master = priv; + /* User avg in seconds * XT_LIMIT_SCALE: convert to jiffies * + 128. */ + priv->prev = jiffies; + priv->credit = user2credits(r->avg * r->burst); /* Credits full. */ if (r->cost == 0) { - /* User avg in seconds * XT_LIMIT_SCALE: convert to jiffies * - 128. */ - r->prev = jiffies; - r->credit = user2credits(r->avg * r->burst); /* Credits full. */ - r->credit_cap = user2credits(r->avg * r->burst); /* Credits full. */ + r->credit_cap = priv->credit; /* Credits full. */ r->cost = user2credits(r->avg); } - return true; + return 0; +} + +static void limit_mt_destroy(const struct xt_mtdtor_param *par) +{ + const struct xt_rateinfo *info = par->matchinfo; + + kfree(info->master); } #ifdef CONFIG_COMPAT @@ -131,7 +150,7 @@ struct compat_xt_rateinfo { /* To keep the full "prev" timestamp, the upper 32 bits are stored in the * master pointer, which does not need to be preserved. */ -static void limit_mt_compat_from_user(void *dst, void *src) +static void limit_mt_compat_from_user(void *dst, const void *src) { const struct compat_xt_rateinfo *cm = src; struct xt_rateinfo m = { @@ -145,7 +164,7 @@ static void limit_mt_compat_from_user(void *dst, void *src) memcpy(dst, &m, sizeof(m)); } -static int limit_mt_compat_to_user(void __user *dst, void *src) +static int limit_mt_compat_to_user(void __user *dst, const void *src) { const struct xt_rateinfo *m = src; struct compat_xt_rateinfo cm = { @@ -167,6 +186,7 @@ static struct xt_match limit_mt_reg __read_mostly = { .family = NFPROTO_UNSPEC, .match = limit_mt, .checkentry = limit_mt_check, + .destroy = limit_mt_destroy, .matchsize = sizeof(struct xt_rateinfo), #ifdef CONFIG_COMPAT .compatsize = sizeof(struct compat_xt_rateinfo), |