1/* Event cache for netfilter. */ 2 3/* (C) 1999-2001 Paul `Rusty' Russell 4 * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org> 5 * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 */ 11 12#include <linux/types.h> 13#include <linux/netfilter.h> 14#include <linux/skbuff.h> 15#include <linux/vmalloc.h> 16#include <linux/stddef.h> 17#include <linux/err.h> 18#include <linux/percpu.h> 19#include <linux/notifier.h> 20#include <linux/kernel.h> 21#include <linux/netdevice.h> 22 23#include <net/netfilter/nf_conntrack.h> 24#include <net/netfilter/nf_conntrack_core.h> 25 26ATOMIC_NOTIFIER_HEAD(nf_conntrack_chain); 27EXPORT_SYMBOL_GPL(nf_conntrack_chain); 28 29ATOMIC_NOTIFIER_HEAD(nf_conntrack_expect_chain); 30EXPORT_SYMBOL_GPL(nf_conntrack_expect_chain); 31 32DEFINE_PER_CPU(struct nf_conntrack_ecache, nf_conntrack_ecache); 33EXPORT_PER_CPU_SYMBOL_GPL(nf_conntrack_ecache); 34 35/* deliver cached events and clear cache entry - must be called with locally 36 * disabled softirqs */ 37static inline void 38__nf_ct_deliver_cached_events(struct nf_conntrack_ecache *ecache) 39{ 40 if (nf_ct_is_confirmed(ecache->ct) && !nf_ct_is_dying(ecache->ct) 41 && ecache->events) 42 atomic_notifier_call_chain(&nf_conntrack_chain, ecache->events, 43 ecache->ct); 44 45 ecache->events = 0; 46 nf_ct_put(ecache->ct); 47 ecache->ct = NULL; 48} 49 50/* Deliver all cached events for a particular conntrack. This is called 51 * by code prior to async packet handling for freeing the skb */ 52void nf_ct_deliver_cached_events(const struct nf_conn *ct) 53{ 54 struct nf_conntrack_ecache *ecache; 55 56 local_bh_disable(); 57 ecache = &__get_cpu_var(nf_conntrack_ecache); 58 if (ecache->ct == ct) 59 __nf_ct_deliver_cached_events(ecache); 60 local_bh_enable(); 61} 62EXPORT_SYMBOL_GPL(nf_ct_deliver_cached_events); 63 64/* Deliver cached events for old pending events, if current conntrack != old */ 65void __nf_ct_event_cache_init(struct nf_conn *ct) 66{ 67 struct nf_conntrack_ecache *ecache; 68 69 /* take care of delivering potentially old events */ 70 ecache = &__get_cpu_var(nf_conntrack_ecache); 71 BUG_ON(ecache->ct == ct); 72 if (ecache->ct) 73 __nf_ct_deliver_cached_events(ecache); 74 /* initialize for this conntrack/packet */ 75 ecache->ct = ct; 76 nf_conntrack_get(&ct->ct_general); 77} 78EXPORT_SYMBOL_GPL(__nf_ct_event_cache_init); 79 80/* flush the event cache - touches other CPU's data and must not be called 81 * while packets are still passing through the code */ 82void nf_ct_event_cache_flush(void) 83{ 84 struct nf_conntrack_ecache *ecache; 85 int cpu; 86 87 for_each_possible_cpu(cpu) { 88 ecache = &per_cpu(nf_conntrack_ecache, cpu); 89 if (ecache->ct) 90 nf_ct_put(ecache->ct); 91 } 92} 93 94int nf_conntrack_register_notifier(struct notifier_block *nb) 95{ 96 return atomic_notifier_chain_register(&nf_conntrack_chain, nb); 97} 98EXPORT_SYMBOL_GPL(nf_conntrack_register_notifier); 99 100int nf_conntrack_unregister_notifier(struct notifier_block *nb) 101{ 102 return atomic_notifier_chain_unregister(&nf_conntrack_chain, nb); 103} 104EXPORT_SYMBOL_GPL(nf_conntrack_unregister_notifier); 105 106int nf_conntrack_expect_register_notifier(struct notifier_block *nb) 107{ 108 return atomic_notifier_chain_register(&nf_conntrack_expect_chain, nb); 109} 110EXPORT_SYMBOL_GPL(nf_conntrack_expect_register_notifier); 111 112int nf_conntrack_expect_unregister_notifier(struct notifier_block *nb) 113{ 114 return atomic_notifier_chain_unregister(&nf_conntrack_expect_chain, nb); 115} 116EXPORT_SYMBOL_GPL(nf_conntrack_expect_unregister_notifier); 117