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authorBart De Schuymer <bdschuym@pandora.be>2003-09-18 19:10:53 +0000
committerBart De Schuymer <bdschuym@pandora.be>2003-09-18 19:10:53 +0000
commit7e511ac918d370dfc278d20f6fed9b5896baea7e (patch)
tree4a64b2baba88d760a7141419a651099f442edd1b /kernel
parente1672b95e409c543392650393b68b875a0223395 (diff)
*** empty log message ***
Diffstat (limited to 'kernel')
-rw-r--r--kernel/linux2.5/include/linux/netfilter_bridge/ebt_limit.h23
-rw-r--r--kernel/linux2.5/net/bridge/netfilter/ebt_limit.c100
2 files changed, 123 insertions, 0 deletions
diff --git a/kernel/linux2.5/include/linux/netfilter_bridge/ebt_limit.h b/kernel/linux2.5/include/linux/netfilter_bridge/ebt_limit.h
new file mode 100644
index 0000000..d8b6500
--- /dev/null
+++ b/kernel/linux2.5/include/linux/netfilter_bridge/ebt_limit.h
@@ -0,0 +1,23 @@
+#ifndef __LINUX_BRIDGE_EBT_LIMIT_H
+#define __LINUX_BRIDGE_EBT_LIMIT_H
+
+#define EBT_LIMIT_MATCH "limit"
+
+/* timings are in milliseconds. */
+#define EBT_LIMIT_SCALE 10000
+
+/* 1/10,000 sec period => max of 10,000/sec. Min rate is then 429490
+ seconds, or one every 59 hours. */
+
+struct ebt_limit_info
+{
+ u_int32_t avg; /* Average secs between packets * scale */
+ u_int32_t burst; /* Period multiplier for upper limit. */
+
+ /* Used internally by the kernel */
+ unsigned long prev;
+ u_int32_t credit;
+ u_int32_t credit_cap, cost;
+};
+
+#endif
diff --git a/kernel/linux2.5/net/bridge/netfilter/ebt_limit.c b/kernel/linux2.5/net/bridge/netfilter/ebt_limit.c
new file mode 100644
index 0000000..eb06bf7
--- /dev/null
+++ b/kernel/linux2.5/net/bridge/netfilter/ebt_limit.c
@@ -0,0 +1,100 @@
+/*
+ * ebt_limit
+ *
+ * Authors:
+ * Tom Marshall <tommy@home.tig-grr.com>
+ *
+ * Mostly copied from netfilter's ipt_limit.c, see that file for explanation
+ *
+ * September, 2003
+ *
+ */
+
+#include <linux/netfilter_bridge/ebtables.h>
+#include <linux/netfilter_bridge/ebt_limit.h>
+#include <linux/module.h>
+
+#include <linux/netdevice.h>
+#include <linux/spinlock.h>
+
+static spinlock_t limit_lock = SPIN_LOCK_UNLOCKED;
+
+#define CREDITS_PER_JIFFY 128
+
+static int ebt_limit_match(const struct sk_buff *skb, const struct net_device *in,
+ const struct net_device *out, const void *data, unsigned int datalen)
+{
+ struct ebt_limit_info *info = (struct ebt_limit_info *)data;
+ unsigned long now = jiffies;
+
+ spin_lock_bh(&limit_lock);
+ info->credit += (now - xchg(&info->prev, now)) * CREDITS_PER_JIFFY;
+ if (info->credit > info->credit_cap)
+ info->credit = info->credit_cap;
+
+ if (info->credit >= info->cost) {
+ /* We're not limited. */
+ info->credit -= info->cost;
+ spin_unlock_bh(&limit_lock);
+ return EBT_MATCH;
+ }
+
+ spin_unlock_bh(&limit_lock);
+ return EBT_NOMATCH;
+}
+
+/* Precision saver. */
+static u_int32_t
+user2credits(u_int32_t user)
+{
+ /* If multiplying would overflow... */
+ if (user > 0xFFFFFFFF / (HZ*CREDITS_PER_JIFFY))
+ /* Divide first. */
+ return (user / EBT_LIMIT_SCALE) * HZ * CREDITS_PER_JIFFY;
+
+ return (user * HZ * CREDITS_PER_JIFFY) / EBT_LIMIT_SCALE;
+}
+
+static int ebt_limit_check(const char *tablename, unsigned int hookmask,
+ const struct ebt_entry *e, void *data, unsigned int datalen)
+{
+ struct ebt_limit_info *info = (struct ebt_limit_info *)data;
+
+ if (datalen != EBT_ALIGN(sizeof(struct ebt_limit_info)))
+ return -EINVAL;
+
+ /* Check for overflow. */
+ if (info->burst == 0
+ || user2credits(info->avg * info->burst) < user2credits(info->avg)) {
+ printk("Overflow in ebt_limit: %u/%u\n",
+ info->avg, info->burst);
+ return -EINVAL;
+ }
+
+ /* User avg in seconds * EBT_LIMIT_SCALE: convert to jiffies * 128. */
+ info->prev = jiffies;
+ info->credit = user2credits(info->avg * info->burst);
+ info->credit_cap = user2credits(info->avg * info->burst);
+ info->cost = user2credits(info->avg);
+ return 0;
+}
+
+static struct ebt_match ebt_limit_reg =
+{
+ {NULL, NULL}, EBT_LIMIT_MATCH, ebt_limit_match, ebt_limit_check, NULL,
+ THIS_MODULE
+};
+
+static int __init init(void)
+{
+ return ebt_register_match(&ebt_limit_reg);
+}
+
+static void __exit fini(void)
+{
+ ebt_unregister_match(&ebt_limit_reg);
+}
+
+module_init(init);
+module_exit(fini);
+MODULE_LICENSE("GPL");