Initial import

1 files changed, 337 insertions, 0 deletions

diff --git a/net/netfilter/nf_conntrack_ecache.c b/net/netfilter/nf_conntrack_ecache.c
new file mode 100644
index 000000000..4e78c57b8
--- /dev/null
+++ b/net/netfilter/nf_conntrack_ecache.c
@@ -0,0 +1,337 @@
+/* Event cache for netfilter. */
+
+/*
+ * (C) 2005 Harald Welte <laforge@gnumonks.org>
+ * (C) 2005 Patrick McHardy <kaber@trash.net>
+ * (C) 2005-2006 Netfilter Core Team <coreteam@netfilter.org>
+ * (C) 2005 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 <linux/export.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);
+
+#define ECACHE_RETRY_WAIT (HZ/10)
+
+enum retry_state {
+	STATE_CONGESTED,
+	STATE_RESTART,
+	STATE_DONE,
+};
+
+static enum retry_state ecache_work_evict_list(struct ct_pcpu *pcpu)
+{
+	struct nf_conn *refs[16];
+	struct nf_conntrack_tuple_hash *h;
+	struct hlist_nulls_node *n;
+	unsigned int evicted = 0;
+	enum retry_state ret = STATE_DONE;
+
+	spin_lock(&pcpu->lock);
+
+	hlist_nulls_for_each_entry(h, n, &pcpu->dying, hnnode) {
+		struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
+
+		if (nf_ct_is_dying(ct))
+			continue;
+
+		if (nf_conntrack_event(IPCT_DESTROY, ct)) {
+			ret = STATE_CONGESTED;
+			break;
+		}
+
+		/* we've got the event delivered, now it's dying */
+		set_bit(IPS_DYING_BIT, &ct->status);
+		refs[evicted] = ct;
+
+		if (++evicted >= ARRAY_SIZE(refs)) {
+			ret = STATE_RESTART;
+			break;
+		}
+	}
+
+	spin_unlock(&pcpu->lock);
+
+	/* can't _put while holding lock */
+	while (evicted)
+		nf_ct_put(refs[--evicted]);
+
+	return ret;
+}
+
+static void ecache_work(struct work_struct *work)
+{
+	struct netns_ct *ctnet =
+		container_of(work, struct netns_ct, ecache_dwork.work);
+	int cpu, delay = -1;
+	struct ct_pcpu *pcpu;
+
+	local_bh_disable();
+
+	for_each_possible_cpu(cpu) {
+		enum retry_state ret;
+
+		pcpu = per_cpu_ptr(ctnet->pcpu_lists, cpu);
+
+		ret = ecache_work_evict_list(pcpu);
+
+		switch (ret) {
+		case STATE_CONGESTED:
+			delay = ECACHE_RETRY_WAIT;
+			goto out;
+		case STATE_RESTART:
+			delay = 0;
+			break;
+		case STATE_DONE:
+			break;
+		}
+	}
+
+ out:
+	local_bh_enable();
+
+	ctnet->ecache_dwork_pending = delay > 0;
+	if (delay >= 0)
+		schedule_delayed_work(&ctnet->ecache_dwork, delay);
+}
+
+/* deliver cached events and clear cache entry - must be called with locally
+ * disabled softirqs */
+void nf_ct_deliver_cached_events(struct nf_conn *ct)
+{
+	struct net *net = nf_ct_net(ct);
+	unsigned long events, missed;
+	struct nf_ct_event_notifier *notify;
+	struct nf_conntrack_ecache *e;
+	struct nf_ct_event item;
+	int ret;
+
+	rcu_read_lock();
+	notify = rcu_dereference(net->ct.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)
+		goto out_unlock;
+
+	/* 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. */
+	missed = e->missed;
+
+	if (!((events | missed) & e->ctmask))
+		goto out_unlock;
+
+	item.ct = ct;
+	item.portid = 0;
+	item.report = 0;
+
+	ret = notify->fcn(events | missed, &item);
+
+	if (likely(ret >= 0 && !missed))
+		goto out_unlock;
+
+	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 net *net,
+				   struct nf_ct_event_notifier *new)
+{
+	int ret;
+	struct nf_ct_event_notifier *notify;
+
+	mutex_lock(&nf_ct_ecache_mutex);
+	notify = rcu_dereference_protected(net->ct.nf_conntrack_event_cb,
+					   lockdep_is_held(&nf_ct_ecache_mutex));
+	if (notify != NULL) {
+		ret = -EBUSY;
+		goto out_unlock;
+	}
+	rcu_assign_pointer(net->ct.nf_conntrack_event_cb, new);
+	ret = 0;
+
+out_unlock:
+	mutex_unlock(&nf_ct_ecache_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(nf_conntrack_register_notifier);
+
+void nf_conntrack_unregister_notifier(struct net *net,
+				      struct nf_ct_event_notifier *new)
+{
+	struct nf_ct_event_notifier *notify;
+
+	mutex_lock(&nf_ct_ecache_mutex);
+	notify = rcu_dereference_protected(net->ct.nf_conntrack_event_cb,
+					   lockdep_is_held(&nf_ct_ecache_mutex));
+	BUG_ON(notify != new);
+	RCU_INIT_POINTER(net->ct.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 net *net,
+				   struct nf_exp_event_notifier *new)
+{
+	int ret;
+	struct nf_exp_event_notifier *notify;
+
+	mutex_lock(&nf_ct_ecache_mutex);
+	notify = rcu_dereference_protected(net->ct.nf_expect_event_cb,
+					   lockdep_is_held(&nf_ct_ecache_mutex));
+	if (notify != NULL) {
+		ret = -EBUSY;
+		goto out_unlock;
+	}
+	rcu_assign_pointer(net->ct.nf_expect_event_cb, new);
+	ret = 0;
+
+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 net *net,
+				      struct nf_exp_event_notifier *new)
+{
+	struct nf_exp_event_notifier *notify;
+
+	mutex_lock(&nf_ct_ecache_mutex);
+	notify = rcu_dereference_protected(net->ct.nf_expect_event_cb,
+					   lockdep_is_held(&nf_ct_ecache_mutex));
+	BUG_ON(notify != new);
+	RCU_INIT_POINTER(net->ct.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;
+
+#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,
+	},
+	{}
+};
+#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;
+
+	/* Don't export sysctls to unprivileged users */
+	if (net->user_ns != &init_user_ns)
+		table[0].procname = NULL;
+
+	net->ct.event_sysctl_header =
+		register_net_sysctl(net, "net/netfilter", 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_pernet_init(struct net *net)
+{
+	net->ct.sysctl_events = nf_ct_events;
+	INIT_DELAYED_WORK(&net->ct.ecache_dwork, ecache_work);
+	return nf_conntrack_event_init_sysctl(net);
+}
+
+void nf_conntrack_ecache_pernet_fini(struct net *net)
+{
+	cancel_delayed_work_sync(&net->ct.ecache_dwork);
+	nf_conntrack_event_fini_sysctl(net);
+}
+
+int nf_conntrack_ecache_init(void)
+{
+	int ret = nf_ct_extend_register(&event_extend);
+	if (ret < 0)
+		pr_err("nf_ct_event: Unable to register event extension.\n");
+	return ret;
+}
+
+void nf_conntrack_ecache_fini(void)
+{
+	nf_ct_extend_unregister(&event_extend);
+}