diff options
Diffstat (limited to 'net/netfilter/nf_conntrack_ecache.c')
| -rw-r--r-- | net/netfilter/nf_conntrack_ecache.c | 266 |
1 files changed, 266 insertions, 0 deletions
diff --git a/net/netfilter/nf_conntrack_ecache.c b/net/netfilter/nf_conntrack_ecache.c new file mode 100644 index 00000000..63a1b915 --- /dev/null +++ b/net/netfilter/nf_conntrack_ecache.c @@ -0,0 +1,266 @@ +/* Event cache for netfilter. */ + +/* (C) 1999-2001 Paul `Rusty' Russell + * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org> + * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org> + * + * 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/types.h> +#include <linux/netfilter.h> +#include <linux/skbuff.h> +#include <linux/vmalloc.h> +#include <linux/stddef.h> +#include <linux/err.h> +#include <linux/percpu.h> +#include <linux/kernel.h> +#include <linux/netdevice.h> +#include <linux/slab.h> + +#include <net/netfilter/nf_conntrack.h> +#include <net/netfilter/nf_conntrack_core.h> +#include <net/netfilter/nf_conntrack_extend.h> + +static DEFINE_MUTEX(nf_ct_ecache_mutex); + +struct nf_ct_event_notifier __rcu *nf_conntrack_event_cb __read_mostly; +EXPORT_SYMBOL_GPL(nf_conntrack_event_cb); + +struct nf_exp_event_notifier __rcu *nf_expect_event_cb __read_mostly; +EXPORT_SYMBOL_GPL(nf_expect_event_cb); + +/* deliver cached events and clear cache entry - must be called with locally + * disabled softirqs */ +void nf_ct_deliver_cached_events(struct nf_conn *ct) +{ + unsigned long events; + struct nf_ct_event_notifier *notify; + struct nf_conntrack_ecache *e; + + rcu_read_lock(); + notify = rcu_dereference(nf_conntrack_event_cb); + if (notify == NULL) + goto out_unlock; + + e = nf_ct_ecache_find(ct); + if (e == NULL) + goto out_unlock; + + events = xchg(&e->cache, 0); + + if (nf_ct_is_confirmed(ct) && !nf_ct_is_dying(ct) && events) { + struct nf_ct_event item = { + .ct = ct, + .pid = 0, + .report = 0 + }; + int ret; + /* We make a copy of the missed event cache without taking + * the lock, thus we may send missed events twice. However, + * this does not harm and it happens very rarely. */ + unsigned long missed = e->missed; + + if (!((events | missed) & e->ctmask)) + goto out_unlock; + + ret = notify->fcn(events | missed, &item); + if (unlikely(ret < 0 || missed)) { + spin_lock_bh(&ct->lock); + if (ret < 0) + e->missed |= events; + else + e->missed &= ~missed; + spin_unlock_bh(&ct->lock); + } + } + +out_unlock: + rcu_read_unlock(); +} +EXPORT_SYMBOL_GPL(nf_ct_deliver_cached_events); + +int nf_conntrack_register_notifier(struct nf_ct_event_notifier *new) +{ + int ret = 0; + struct nf_ct_event_notifier *notify; + + mutex_lock(&nf_ct_ecache_mutex); + notify = rcu_dereference_protected(nf_conntrack_event_cb, + lockdep_is_held(&nf_ct_ecache_mutex)); + if (notify != NULL) { + ret = -EBUSY; + goto out_unlock; + } + rcu_assign_pointer(nf_conntrack_event_cb, new); + mutex_unlock(&nf_ct_ecache_mutex); + return ret; + +out_unlock: + mutex_unlock(&nf_ct_ecache_mutex); + return ret; +} +EXPORT_SYMBOL_GPL(nf_conntrack_register_notifier); + +void nf_conntrack_unregister_notifier(struct nf_ct_event_notifier *new) +{ + struct nf_ct_event_notifier *notify; + + mutex_lock(&nf_ct_ecache_mutex); + notify = rcu_dereference_protected(nf_conntrack_event_cb, + lockdep_is_held(&nf_ct_ecache_mutex)); + BUG_ON(notify != new); + rcu_assign_pointer(nf_conntrack_event_cb, NULL); + mutex_unlock(&nf_ct_ecache_mutex); +} +EXPORT_SYMBOL_GPL(nf_conntrack_unregister_notifier); + +int nf_ct_expect_register_notifier(struct nf_exp_event_notifier *new) +{ + int ret = 0; + struct nf_exp_event_notifier *notify; + + mutex_lock(&nf_ct_ecache_mutex); + notify = rcu_dereference_protected(nf_expect_event_cb, + lockdep_is_held(&nf_ct_ecache_mutex)); + if (notify != NULL) { + ret = -EBUSY; + goto out_unlock; + } + rcu_assign_pointer(nf_expect_event_cb, new); + mutex_unlock(&nf_ct_ecache_mutex); + return ret; + +out_unlock: + mutex_unlock(&nf_ct_ecache_mutex); + return ret; +} +EXPORT_SYMBOL_GPL(nf_ct_expect_register_notifier); + +void nf_ct_expect_unregister_notifier(struct nf_exp_event_notifier *new) +{ + struct nf_exp_event_notifier *notify; + + mutex_lock(&nf_ct_ecache_mutex); + notify = rcu_dereference_protected(nf_expect_event_cb, + lockdep_is_held(&nf_ct_ecache_mutex)); + BUG_ON(notify != new); + rcu_assign_pointer(nf_expect_event_cb, NULL); + mutex_unlock(&nf_ct_ecache_mutex); +} +EXPORT_SYMBOL_GPL(nf_ct_expect_unregister_notifier); + +#define NF_CT_EVENTS_DEFAULT 1 +static int nf_ct_events __read_mostly = NF_CT_EVENTS_DEFAULT; +static int nf_ct_events_retry_timeout __read_mostly = 15*HZ; + +#ifdef CONFIG_SYSCTL +static struct ctl_table event_sysctl_table[] = { + { + .procname = "nf_conntrack_events", + .data = &init_net.ct.sysctl_events, + .maxlen = sizeof(unsigned int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, + { + .procname = "nf_conntrack_events_retry_timeout", + .data = &init_net.ct.sysctl_events_retry_timeout, + .maxlen = sizeof(unsigned int), + .mode = 0644, + .proc_handler = proc_dointvec_jiffies, + }, + {} +}; +#endif /* CONFIG_SYSCTL */ + +static struct nf_ct_ext_type event_extend __read_mostly = { + .len = sizeof(struct nf_conntrack_ecache), + .align = __alignof__(struct nf_conntrack_ecache), + .id = NF_CT_EXT_ECACHE, +}; + +#ifdef CONFIG_SYSCTL +static int nf_conntrack_event_init_sysctl(struct net *net) +{ + struct ctl_table *table; + + table = kmemdup(event_sysctl_table, sizeof(event_sysctl_table), + GFP_KERNEL); + if (!table) + goto out; + + table[0].data = &net->ct.sysctl_events; + table[1].data = &net->ct.sysctl_events_retry_timeout; + + net->ct.event_sysctl_header = + register_net_sysctl_table(net, + nf_net_netfilter_sysctl_path, table); + if (!net->ct.event_sysctl_header) { + printk(KERN_ERR "nf_ct_event: can't register to sysctl.\n"); + goto out_register; + } + return 0; + +out_register: + kfree(table); +out: + return -ENOMEM; +} + +static void nf_conntrack_event_fini_sysctl(struct net *net) +{ + struct ctl_table *table; + + table = net->ct.event_sysctl_header->ctl_table_arg; + unregister_net_sysctl_table(net->ct.event_sysctl_header); + kfree(table); +} +#else +static int nf_conntrack_event_init_sysctl(struct net *net) +{ + return 0; +} + +static void nf_conntrack_event_fini_sysctl(struct net *net) +{ +} +#endif /* CONFIG_SYSCTL */ + +int nf_conntrack_ecache_init(struct net *net) +{ + int ret; + + net->ct.sysctl_events = nf_ct_events; + net->ct.sysctl_events_retry_timeout = nf_ct_events_retry_timeout; + + if (net_eq(net, &init_net)) { + ret = nf_ct_extend_register(&event_extend); + if (ret < 0) { + printk(KERN_ERR "nf_ct_event: Unable to register " + "event extension.\n"); + goto out_extend_register; + } + } + + ret = nf_conntrack_event_init_sysctl(net); + if (ret < 0) + goto out_sysctl; + + return 0; + +out_sysctl: + if (net_eq(net, &init_net)) + nf_ct_extend_unregister(&event_extend); +out_extend_register: + return ret; +} + +void nf_conntrack_ecache_fini(struct net *net) +{ + nf_conntrack_event_fini_sysctl(net); + if (net_eq(net, &init_net)) + nf_ct_extend_unregister(&event_extend); +} |