diff options
Diffstat (limited to 'net/ipv6/netfilter/ip6t_limit.c')
| -rw-r--r-- | net/ipv6/netfilter/ip6t_limit.c | 147 |
1 files changed, 0 insertions, 147 deletions
diff --git a/net/ipv6/netfilter/ip6t_limit.c b/net/ipv6/netfilter/ip6t_limit.c deleted file mode 100644 index fb782f610be20..0000000000000 --- a/net/ipv6/netfilter/ip6t_limit.c +++ /dev/null @@ -1,147 +0,0 @@ -/* 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> - * - * 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/spinlock.h> -#include <linux/interrupt.h> - -#include <linux/netfilter_ipv6/ip6_tables.h> -#include <linux/netfilter_ipv6/ip6t_limit.h> - -MODULE_LICENSE("GPL"); -MODULE_AUTHOR("Herve Eychenne <rv@wallfire.org>"); -MODULE_DESCRIPTION("rate limiting within ip6tables"); - -/* The algorithm used is the Simple Token Bucket Filter (TBF) - * see net/sched/sch_tbf.c in the linux source tree - */ - -static DEFINE_SPINLOCK(limit_lock); - -/* Rusty: This is my (non-mathematically-inclined) understanding of - this algorithm. The `average rate' in jiffies becomes your initial - amount of credit `credit' and the most credit you can ever have - `credit_cap'. The `peak rate' becomes the cost of passing the - test, `cost'. - - `prev' tracks the last packet hit: you gain one credit per jiffy. - If you get credit balance more than this, the extra credit is - discarded. Every time the match passes, you lose `cost' credits; - if you don't have that many, the test fails. - - See Alexey's formal explanation in net/sched/sch_tbf.c. - - To avoid underflow, we multiply by 128 (ie. you get 128 credits per - jiffy). Hence a cost of 2^32-1, means one pass per 32768 seconds - at 1024HZ (or one every 9 hours). A cost of 1 means 12800 passes - per second at 100HZ. */ - -#define CREDITS_PER_JIFFY 128 - -static int -ip6t_limit_match(const struct sk_buff *skb, - const struct net_device *in, - const struct net_device *out, - const void *matchinfo, - int offset, - unsigned int protoff, - int *hotdrop) -{ - struct ip6t_rateinfo *r = ((struct ip6t_rateinfo *)matchinfo)->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; - - if (r->credit >= r->cost) { - /* We're not limited. */ - r->credit -= r->cost; - spin_unlock_bh(&limit_lock); - return 1; - } - - spin_unlock_bh(&limit_lock); - return 0; -} - -/* 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 / IP6T_LIMIT_SCALE) * HZ * CREDITS_PER_JIFFY; - - return (user * HZ * CREDITS_PER_JIFFY) / IP6T_LIMIT_SCALE; -} - -static int -ip6t_limit_checkentry(const char *tablename, - const struct ip6t_ip6 *ip, - void *matchinfo, - unsigned int matchsize, - unsigned int hook_mask) -{ - struct ip6t_rateinfo *r = matchinfo; - - if (matchsize != IP6T_ALIGN(sizeof(struct ip6t_rateinfo))) - return 0; - - /* Check for overflow. */ - if (r->burst == 0 - || user2credits(r->avg * r->burst) < user2credits(r->avg)) { - printk("Call rusty: overflow in ip6t_limit: %u/%u\n", - r->avg, r->burst); - return 0; - } - - /* User avg in seconds * IP6T_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); - - /* For SMP, we only want to use one set of counters. */ - r->master = r; - - return 1; -} - -static struct ip6t_match ip6t_limit_reg = { - .name = "limit", - .match = ip6t_limit_match, - .checkentry = ip6t_limit_checkentry, - .me = THIS_MODULE, -}; - -static int __init init(void) -{ - if (ip6t_register_match(&ip6t_limit_reg)) - return -EINVAL; - return 0; -} - -static void __exit fini(void) -{ - ip6t_unregister_match(&ip6t_limit_reg); -} - -module_init(init); -module_exit(fini); |