[linux-block.git] / net / core / fib_notifier.c

#include <linux/rtnetlink.h>
#include <linux/notifier.h>
#include <linux/rcupdate.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <net/net_namespace.h>
#include <net/fib_notifier.h>

static ATOMIC_NOTIFIER_HEAD(fib_chain);

int call_fib_notifier(struct notifier_block *nb, struct net *net,
		      enum fib_event_type event_type,
		      struct fib_notifier_info *info)
{
	info->net = net;
	return nb->notifier_call(nb, event_type, info);
}
EXPORT_SYMBOL(call_fib_notifier);

int call_fib_notifiers(struct net *net, enum fib_event_type event_type,
		       struct fib_notifier_info *info)
{
	info->net = net;
	return atomic_notifier_call_chain(&fib_chain, event_type, info);
}
EXPORT_SYMBOL(call_fib_notifiers);

static unsigned int fib_seq_sum(void)
{
	struct fib_notifier_ops *ops;
	unsigned int fib_seq = 0;
	struct net *net;

	rtnl_lock();
	for_each_net(net) {
		list_for_each_entry(ops, &net->fib_notifier_ops, list)
			fib_seq += ops->fib_seq_read(net);
	}
	rtnl_unlock();

	return fib_seq;
}

static int fib_net_dump(struct net *net, struct notifier_block *nb)
{
	struct fib_notifier_ops *ops;

	list_for_each_entry_rcu(ops, &net->fib_notifier_ops, list) {
		int err = ops->fib_dump(net, nb);

		if (err)
			return err;
	}

	return 0;
}

static bool fib_dump_is_consistent(struct notifier_block *nb,
				   void (*cb)(struct notifier_block *nb),
				   unsigned int fib_seq)
{
	atomic_notifier_chain_register(&fib_chain, nb);
	if (fib_seq == fib_seq_sum())
		return true;
	atomic_notifier_chain_unregister(&fib_chain, nb);
	if (cb)
		cb(nb);
	return false;
}

#define FIB_DUMP_MAX_RETRIES 5
int register_fib_notifier(struct notifier_block *nb,
			  void (*cb)(struct notifier_block *nb))
{
	int retries = 0;
	int err;

	do {
		unsigned int fib_seq = fib_seq_sum();
		struct net *net;

		rcu_read_lock();
		for_each_net_rcu(net) {
			err = fib_net_dump(net, nb);
			if (err)
				goto err_fib_net_dump;
		}
		rcu_read_unlock();

		if (fib_dump_is_consistent(nb, cb, fib_seq))
			return 0;
	} while (++retries < FIB_DUMP_MAX_RETRIES);

	return -EBUSY;

err_fib_net_dump:
	rcu_read_unlock();
	return err;
}
EXPORT_SYMBOL(register_fib_notifier);

int unregister_fib_notifier(struct notifier_block *nb)
{
	return atomic_notifier_chain_unregister(&fib_chain, nb);
}
EXPORT_SYMBOL(unregister_fib_notifier);

static int __fib_notifier_ops_register(struct fib_notifier_ops *ops,
				       struct net *net)
{
	struct fib_notifier_ops *o;

	list_for_each_entry(o, &net->fib_notifier_ops, list)
		if (ops->family == o->family)
			return -EEXIST;
	list_add_tail_rcu(&ops->list, &net->fib_notifier_ops);
	return 0;
}

struct fib_notifier_ops *
fib_notifier_ops_register(const struct fib_notifier_ops *tmpl, struct net *net)
{
	struct fib_notifier_ops *ops;
	int err;

	ops = kmemdup(tmpl, sizeof(*ops), GFP_KERNEL);
	if (!ops)
		return ERR_PTR(-ENOMEM);

	err = __fib_notifier_ops_register(ops, net);
	if (err)
		goto err_register;

	return ops;

err_register:
	kfree(ops);
	return ERR_PTR(err);
}
EXPORT_SYMBOL(fib_notifier_ops_register);

void fib_notifier_ops_unregister(struct fib_notifier_ops *ops)
{
	list_del_rcu(&ops->list);
	kfree_rcu(ops, rcu);
}
EXPORT_SYMBOL(fib_notifier_ops_unregister);

static int __net_init fib_notifier_net_init(struct net *net)
{
	INIT_LIST_HEAD(&net->fib_notifier_ops);
	return 0;
}

static struct pernet_operations fib_notifier_net_ops = {
	.init = fib_notifier_net_init,
};

static int __init fib_notifier_init(void)
{
	return register_pernet_subsys(&fib_notifier_net_ops);
}

subsys_initcall(fib_notifier_init);
Commit	Line	Data
04b1d4e5 IS	1	#include <linux/rtnetlink.h>
	2	#include <linux/notifier.h>
	3	#include <linux/rcupdate.h>
	4	#include <linux/kernel.h>
	5	#include <linux/init.h>
	6	#include <net/net_namespace.h>
	7	#include <net/fib_notifier.h>
	8
	9	static ATOMIC_NOTIFIER_HEAD(fib_chain);
	10
	11	int call_fib_notifier(struct notifier_block nb, struct net net,
	12	enum fib_event_type event_type,
	13	struct fib_notifier_info *info)
	14	{
	15	info->net = net;
	16	return nb->notifier_call(nb, event_type, info);
	17	}
	18	EXPORT_SYMBOL(call_fib_notifier);
	19
	20	int call_fib_notifiers(struct net *net, enum fib_event_type event_type,
	21	struct fib_notifier_info *info)
	22	{
	23	info->net = net;
	24	return atomic_notifier_call_chain(&fib_chain, event_type, info);
	25	}
	26	EXPORT_SYMBOL(call_fib_notifiers);
	27
	28	static unsigned int fib_seq_sum(void)
	29	{
	30	struct fib_notifier_ops *ops;
	31	unsigned int fib_seq = 0;
	32	struct net *net;
	33
	34	rtnl_lock();
	35	for_each_net(net) {
	36	list_for_each_entry(ops, &net->fib_notifier_ops, list)
	37	fib_seq += ops->fib_seq_read(net);
	38	}
	39	rtnl_unlock();
	40
	41	return fib_seq;
	42	}
	43
	44	static int fib_net_dump(struct net net, struct notifier_block nb)
	45	{
	46	struct fib_notifier_ops *ops;
	47
	48	list_for_each_entry_rcu(ops, &net->fib_notifier_ops, list) {
	49	int err = ops->fib_dump(net, nb);
	50
	51	if (err)
	52	return err;
	53	}
	54
	55	return 0;
	56	}
	57
	58	static bool fib_dump_is_consistent(struct notifier_block *nb,
	59	void (cb)(struct notifier_block nb),
	60	unsigned int fib_seq)
	61	{
	62	atomic_notifier_chain_register(&fib_chain, nb);
	63	if (fib_seq == fib_seq_sum())
	64	return true;
65	atomic_notifier_chain_unregister(&fib_chain, nb);
66	if (cb)
67	cb(nb);
68	return false;
69	}
70
71	#define FIB_DUMP_MAX_RETRIES 5
72	int register_fib_notifier(struct notifier_block *nb,
73	void (cb)(struct notifier_block nb))
74	{
75	int retries = 0;
76	int err;
77
78	do {
79	unsigned int fib_seq = fib_seq_sum();
80	struct net *net;
81
82	rcu_read_lock();
83	for_each_net_rcu(net) {
84	err = fib_net_dump(net, nb);
85	if (err)
86	goto err_fib_net_dump;
87	}
88	rcu_read_unlock();
89
90	if (fib_dump_is_consistent(nb, cb, fib_seq))
91	return 0;
92	} while (++retries < FIB_DUMP_MAX_RETRIES);
93
94	return -EBUSY;
95
96	err_fib_net_dump:
97	rcu_read_unlock();
98	return err;
99	}
100	EXPORT_SYMBOL(register_fib_notifier);
101
102	int unregister_fib_notifier(struct notifier_block *nb)
103	{
104	return atomic_notifier_chain_unregister(&fib_chain, nb);
105	}
106	EXPORT_SYMBOL(unregister_fib_notifier);
107
108	static int __fib_notifier_ops_register(struct fib_notifier_ops *ops,
109	struct net *net)
110	{
111	struct fib_notifier_ops *o;
112
113	list_for_each_entry(o, &net->fib_notifier_ops, list)
114	if (ops->family == o->family)
115	return -EEXIST;
116	list_add_tail_rcu(&ops->list, &net->fib_notifier_ops);
117	return 0;
118	}
119
120	struct fib_notifier_ops *
121	fib_notifier_ops_register(const struct fib_notifier_ops tmpl, struct net net)
122	{
123	struct fib_notifier_ops *ops;
124	int err;
125
126	ops = kmemdup(tmpl, sizeof(*ops), GFP_KERNEL);
127	if (!ops)
128	return ERR_PTR(-ENOMEM);
129
130	err = __fib_notifier_ops_register(ops, net);
131	if (err)
132	goto err_register;
133
134	return ops;
135
136	err_register:
137	kfree(ops);
138	return ERR_PTR(err);
139	}
140	EXPORT_SYMBOL(fib_notifier_ops_register);
141
142	void fib_notifier_ops_unregister(struct fib_notifier_ops *ops)
143	{
144	list_del_rcu(&ops->list);
145	kfree_rcu(ops, rcu);
146	}
147	EXPORT_SYMBOL(fib_notifier_ops_unregister);
148
149	static int __net_init fib_notifier_net_init(struct net *net)
150	{
151	INIT_LIST_HEAD(&net->fib_notifier_ops);
152	return 0;
153	}
154
155	static struct pernet_operations fib_notifier_net_ops = {
156	.init = fib_notifier_net_init,
157	};
158
159	static int __init fib_notifier_init(void)
160	{
161	return register_pernet_subsys(&fib_notifier_net_ops);
162	}
163
164	subsys_initcall(fib_notifier_init);