1 #include <linux/rtnetlink.h>
2 #include <linux/notifier.h>
3 #include <linux/rcupdate.h>
4 #include <linux/kernel.h>
5 #include <linux/module.h>
6 #include <linux/init.h>
7 #include <net/net_namespace.h>
8 #include <net/fib_notifier.h>
10 static ATOMIC_NOTIFIER_HEAD(fib_chain);
12 int call_fib_notifier(struct notifier_block *nb, struct net *net,
13 enum fib_event_type event_type,
14 struct fib_notifier_info *info)
17 return nb->notifier_call(nb, event_type, info);
19 EXPORT_SYMBOL(call_fib_notifier);
21 int call_fib_notifiers(struct net *net, enum fib_event_type event_type,
22 struct fib_notifier_info *info)
25 return atomic_notifier_call_chain(&fib_chain, event_type, info);
27 EXPORT_SYMBOL(call_fib_notifiers);
29 static unsigned int fib_seq_sum(void)
31 struct fib_notifier_ops *ops;
32 unsigned int fib_seq = 0;
37 list_for_each_entry(ops, &net->fib_notifier_ops, list) {
38 if (!try_module_get(ops->owner))
40 fib_seq += ops->fib_seq_read(net);
41 module_put(ops->owner);
49 static int fib_net_dump(struct net *net, struct notifier_block *nb)
51 struct fib_notifier_ops *ops;
53 list_for_each_entry_rcu(ops, &net->fib_notifier_ops, list) {
56 if (!try_module_get(ops->owner))
58 err = ops->fib_dump(net, nb);
59 module_put(ops->owner);
67 static bool fib_dump_is_consistent(struct notifier_block *nb,
68 void (*cb)(struct notifier_block *nb),
71 atomic_notifier_chain_register(&fib_chain, nb);
72 if (fib_seq == fib_seq_sum())
74 atomic_notifier_chain_unregister(&fib_chain, nb);
80 #define FIB_DUMP_MAX_RETRIES 5
81 int register_fib_notifier(struct notifier_block *nb,
82 void (*cb)(struct notifier_block *nb))
88 unsigned int fib_seq = fib_seq_sum();
92 for_each_net_rcu(net) {
93 err = fib_net_dump(net, nb);
95 goto err_fib_net_dump;
99 if (fib_dump_is_consistent(nb, cb, fib_seq))
101 } while (++retries < FIB_DUMP_MAX_RETRIES);
109 EXPORT_SYMBOL(register_fib_notifier);
111 int unregister_fib_notifier(struct notifier_block *nb)
113 return atomic_notifier_chain_unregister(&fib_chain, nb);
115 EXPORT_SYMBOL(unregister_fib_notifier);
117 static int __fib_notifier_ops_register(struct fib_notifier_ops *ops,
120 struct fib_notifier_ops *o;
122 list_for_each_entry(o, &net->fib_notifier_ops, list)
123 if (ops->family == o->family)
125 list_add_tail_rcu(&ops->list, &net->fib_notifier_ops);
129 struct fib_notifier_ops *
130 fib_notifier_ops_register(const struct fib_notifier_ops *tmpl, struct net *net)
132 struct fib_notifier_ops *ops;
135 ops = kmemdup(tmpl, sizeof(*ops), GFP_KERNEL);
137 return ERR_PTR(-ENOMEM);
139 err = __fib_notifier_ops_register(ops, net);
149 EXPORT_SYMBOL(fib_notifier_ops_register);
151 void fib_notifier_ops_unregister(struct fib_notifier_ops *ops)
153 list_del_rcu(&ops->list);
156 EXPORT_SYMBOL(fib_notifier_ops_unregister);
158 static int __net_init fib_notifier_net_init(struct net *net)
160 INIT_LIST_HEAD(&net->fib_notifier_ops);
164 static struct pernet_operations fib_notifier_net_ops = {
165 .init = fib_notifier_net_init,
168 static int __init fib_notifier_init(void)
170 return register_pernet_subsys(&fib_notifier_net_ops);
173 subsys_initcall(fib_notifier_init);