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Diffstat (limited to 'net/netfilter/xt_limit.c')
-rw-r--r--net/netfilter/xt_limit.c190
1 files changed, 111 insertions, 79 deletions
diff --git a/net/netfilter/xt_limit.c b/net/netfilter/xt_limit.c
index e91c1a444e7..bef85059655 100644
--- a/net/netfilter/xt_limit.c
+++ b/net/netfilter/xt_limit.c
@@ -1,18 +1,14 @@
-/* Kernel module to control the rate
- *
- * 2 September 1999: Changed from the target RATE to the match
- * `limit', removed logging. Did I mention that
- * Alexey is a fucking genius?
- * Rusty Russell (rusty@rustcorp.com.au). */
-
-/* (C) 1999 Jérôme de Vivie <devivie@info.enserb.u-bordeaux.fr>
- * (C) 1999 Hervé Eychenne <eychenne@info.enserb.u-bordeaux.fr>
+/* (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>
@@ -21,9 +17,14 @@
#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("iptables rate limit match");
+MODULE_DESCRIPTION("Xtables: rate-limit match");
MODULE_ALIAS("ipt_limit");
MODULE_ALIAS("ip6t_limit");
@@ -64,38 +65,31 @@ static DEFINE_SPINLOCK(limit_lock);
#define CREDITS_PER_JIFFY POW2_BELOW32(MAX_CPJ)
-static int
-ipt_limit_match(const struct sk_buff *skb,
- const struct net_device *in,
- const struct net_device *out,
- const struct xt_match *match,
- const void *matchinfo,
- int offset,
- unsigned int protoff,
- int *hotdrop)
+static bool
+limit_mt(const struct sk_buff *skb, struct xt_action_param *par)
{
- struct xt_rateinfo *r = ((struct xt_rateinfo *)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 1;
+ return true;
}
- spin_unlock_bh(&limit_lock);
- return 0;
+ spin_unlock_bh(&limit_lock);
+ return false;
}
/* 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))
@@ -105,74 +99,112 @@ user2credits(u_int32_t user)
return (user * HZ * CREDITS_PER_JIFFY) / XT_LIMIT_SCALE;
}
-static int
-ipt_limit_checkentry(const char *tablename,
- const void *inf,
- const struct xt_match *match,
- void *matchinfo,
- unsigned int matchsize,
- unsigned int hook_mask)
+static int limit_mt_check(const struct xt_mtchk_param *par)
{
- struct xt_rateinfo *r = matchinfo;
+ 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 0;
+ pr_info("Overflow, try lower: %u/%u\n",
+ r->avg, r->burst);
+ return -ERANGE;
}
+ 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. */
- r->prev = jiffies;
- r->credit = user2credits(r->avg * r->burst); /* Credits full. */
- r->credit_cap = user2credits(r->avg * r->burst); /* Credits full. */
- r->cost = user2credits(r->avg);
+ priv->prev = jiffies;
+ priv->credit = user2credits(r->avg * r->burst); /* Credits full. */
+ if (r->cost == 0) {
+ r->credit_cap = priv->credit; /* Credits full. */
+ r->cost = user2credits(r->avg);
+ }
+ return 0;
+}
- /* For SMP, we only want to use one set of counters. */
- r->master = r;
+static void limit_mt_destroy(const struct xt_mtdtor_param *par)
+{
+ const struct xt_rateinfo *info = par->matchinfo;
- return 1;
+ kfree(info->master);
}
-static struct xt_match ipt_limit_reg = {
- .name = "limit",
- .match = ipt_limit_match,
- .matchsize = sizeof(struct xt_rateinfo),
- .checkentry = ipt_limit_checkentry,
- .family = AF_INET,
- .me = THIS_MODULE,
+#ifdef CONFIG_COMPAT
+struct compat_xt_rateinfo {
+ u_int32_t avg;
+ u_int32_t burst;
+
+ compat_ulong_t prev;
+ u_int32_t credit;
+ u_int32_t credit_cap, cost;
+
+ u_int32_t master;
};
-static struct xt_match limit6_reg = {
- .name = "limit",
- .match = ipt_limit_match,
- .matchsize = sizeof(struct xt_rateinfo),
- .checkentry = ipt_limit_checkentry,
- .family = AF_INET6,
- .me = THIS_MODULE,
+
+/* 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, const void *src)
+{
+ const struct compat_xt_rateinfo *cm = src;
+ struct xt_rateinfo m = {
+ .avg = cm->avg,
+ .burst = cm->burst,
+ .prev = cm->prev | (unsigned long)cm->master << 32,
+ .credit = cm->credit,
+ .credit_cap = cm->credit_cap,
+ .cost = cm->cost,
+ };
+ memcpy(dst, &m, sizeof(m));
+}
+
+static int limit_mt_compat_to_user(void __user *dst, const void *src)
+{
+ const struct xt_rateinfo *m = src;
+ struct compat_xt_rateinfo cm = {
+ .avg = m->avg,
+ .burst = m->burst,
+ .prev = m->prev,
+ .credit = m->credit,
+ .credit_cap = m->credit_cap,
+ .cost = m->cost,
+ .master = m->prev >> 32,
+ };
+ return copy_to_user(dst, &cm, sizeof(cm)) ? -EFAULT : 0;
+}
+#endif /* CONFIG_COMPAT */
+
+static struct xt_match limit_mt_reg __read_mostly = {
+ .name = "limit",
+ .revision = 0,
+ .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),
+ .compat_from_user = limit_mt_compat_from_user,
+ .compat_to_user = limit_mt_compat_to_user,
+#endif
+ .me = THIS_MODULE,
};
-static int __init init(void)
+static int __init limit_mt_init(void)
{
- int ret;
-
- ret = xt_register_match(&ipt_limit_reg);
- if (ret)
- return ret;
-
- ret = xt_register_match(&limit6_reg);
- if (ret)
- xt_unregister_match(&ipt_limit_reg);
-
- return ret;
+ return xt_register_match(&limit_mt_reg);
}
-static void __exit fini(void)
+static void __exit limit_mt_exit(void)
{
- xt_unregister_match(&ipt_limit_reg);
- xt_unregister_match(&limit6_reg);
+ xt_unregister_match(&limit_mt_reg);
}
-module_init(init);
-module_exit(fini);
+module_init(limit_mt_init);
+module_exit(limit_mt_exit);
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-12-06 14:02:07 +0000