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/netns/generic.h>
9 #include <net/fib_notifier.h>
11 static unsigned int fib_notifier_net_id;
13 struct fib_notifier_net {
14 struct list_head fib_notifier_ops;
17 static ATOMIC_NOTIFIER_HEAD(fib_chain);
19 int call_fib_notifier(struct notifier_block *nb, struct net *net,
20 enum fib_event_type event_type,
21 struct fib_notifier_info *info)
26 err = nb->notifier_call(nb, event_type, info);
27 return notifier_to_errno(err);
29 EXPORT_SYMBOL(call_fib_notifier);
31 int call_fib_notifiers(struct net *net, enum fib_event_type event_type,
32 struct fib_notifier_info *info)
37 err = atomic_notifier_call_chain(&fib_chain, event_type, info);
38 return notifier_to_errno(err);
40 EXPORT_SYMBOL(call_fib_notifiers);
42 static unsigned int fib_seq_sum(void)
44 struct fib_notifier_net *fn_net;
45 struct fib_notifier_ops *ops;
46 unsigned int fib_seq = 0;
50 down_read(&net_rwsem);
52 fn_net = net_generic(net, fib_notifier_net_id);
54 list_for_each_entry_rcu(ops, &fn_net->fib_notifier_ops, list) {
55 if (!try_module_get(ops->owner))
57 fib_seq += ops->fib_seq_read(net);
58 module_put(ops->owner);
68 static int fib_net_dump(struct net *net, struct notifier_block *nb)
70 struct fib_notifier_net *fn_net = net_generic(net, fib_notifier_net_id);
71 struct fib_notifier_ops *ops;
73 list_for_each_entry_rcu(ops, &fn_net->fib_notifier_ops, list) {
76 if (!try_module_get(ops->owner))
78 err = ops->fib_dump(net, nb);
79 module_put(ops->owner);
87 static bool fib_dump_is_consistent(struct notifier_block *nb,
88 void (*cb)(struct notifier_block *nb),
91 atomic_notifier_chain_register(&fib_chain, nb);
92 if (fib_seq == fib_seq_sum())
94 atomic_notifier_chain_unregister(&fib_chain, nb);
100 #define FIB_DUMP_MAX_RETRIES 5
101 int register_fib_notifier(struct notifier_block *nb,
102 void (*cb)(struct notifier_block *nb))
108 unsigned int fib_seq = fib_seq_sum();
112 for_each_net_rcu(net) {
113 err = fib_net_dump(net, nb);
115 goto err_fib_net_dump;
119 if (fib_dump_is_consistent(nb, cb, fib_seq))
121 } while (++retries < FIB_DUMP_MAX_RETRIES);
129 EXPORT_SYMBOL(register_fib_notifier);
131 int unregister_fib_notifier(struct notifier_block *nb)
133 return atomic_notifier_chain_unregister(&fib_chain, nb);
135 EXPORT_SYMBOL(unregister_fib_notifier);
137 static int __fib_notifier_ops_register(struct fib_notifier_ops *ops,
140 struct fib_notifier_net *fn_net = net_generic(net, fib_notifier_net_id);
141 struct fib_notifier_ops *o;
143 list_for_each_entry(o, &fn_net->fib_notifier_ops, list)
144 if (ops->family == o->family)
146 list_add_tail_rcu(&ops->list, &fn_net->fib_notifier_ops);
150 struct fib_notifier_ops *
151 fib_notifier_ops_register(const struct fib_notifier_ops *tmpl, struct net *net)
153 struct fib_notifier_ops *ops;
156 ops = kmemdup(tmpl, sizeof(*ops), GFP_KERNEL);
158 return ERR_PTR(-ENOMEM);
160 err = __fib_notifier_ops_register(ops, net);
170 EXPORT_SYMBOL(fib_notifier_ops_register);
172 void fib_notifier_ops_unregister(struct fib_notifier_ops *ops)
174 list_del_rcu(&ops->list);
177 EXPORT_SYMBOL(fib_notifier_ops_unregister);
179 static int __net_init fib_notifier_net_init(struct net *net)
181 struct fib_notifier_net *fn_net = net_generic(net, fib_notifier_net_id);
183 INIT_LIST_HEAD(&fn_net->fib_notifier_ops);
187 static void __net_exit fib_notifier_net_exit(struct net *net)
189 struct fib_notifier_net *fn_net = net_generic(net, fib_notifier_net_id);
191 WARN_ON_ONCE(!list_empty(&fn_net->fib_notifier_ops));
194 static struct pernet_operations fib_notifier_net_ops = {
195 .init = fib_notifier_net_init,
196 .exit = fib_notifier_net_exit,
197 .id = &fib_notifier_net_id,
198 .size = sizeof(struct fib_notifier_net),
201 static int __init fib_notifier_init(void)
203 return register_pernet_subsys(&fib_notifier_net_ops);
206 subsys_initcall(fib_notifier_init);