Loading...
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>
10
11static unsigned int fib_notifier_net_id;
12
13struct fib_notifier_net {
14 struct list_head fib_notifier_ops;
15 struct atomic_notifier_head fib_chain;
16};
17
18int call_fib_notifier(struct notifier_block *nb,
19 enum fib_event_type event_type,
20 struct fib_notifier_info *info)
21{
22 int err;
23
24 err = nb->notifier_call(nb, event_type, info);
25 return notifier_to_errno(err);
26}
27EXPORT_SYMBOL(call_fib_notifier);
28
29int call_fib_notifiers(struct net *net, enum fib_event_type event_type,
30 struct fib_notifier_info *info)
31{
32 struct fib_notifier_net *fn_net = net_generic(net, fib_notifier_net_id);
33 int err;
34
35 err = atomic_notifier_call_chain(&fn_net->fib_chain, event_type, info);
36 return notifier_to_errno(err);
37}
38EXPORT_SYMBOL(call_fib_notifiers);
39
40static unsigned int fib_seq_sum(struct net *net)
41{
42 struct fib_notifier_net *fn_net = net_generic(net, fib_notifier_net_id);
43 struct fib_notifier_ops *ops;
44 unsigned int fib_seq = 0;
45
46 rtnl_lock();
47 rcu_read_lock();
48 list_for_each_entry_rcu(ops, &fn_net->fib_notifier_ops, list) {
49 if (!try_module_get(ops->owner))
50 continue;
51 fib_seq += ops->fib_seq_read(net);
52 module_put(ops->owner);
53 }
54 rcu_read_unlock();
55 rtnl_unlock();
56
57 return fib_seq;
58}
59
60static int fib_net_dump(struct net *net, struct notifier_block *nb,
61 struct netlink_ext_ack *extack)
62{
63 struct fib_notifier_net *fn_net = net_generic(net, fib_notifier_net_id);
64 struct fib_notifier_ops *ops;
65 int err = 0;
66
67 rcu_read_lock();
68 list_for_each_entry_rcu(ops, &fn_net->fib_notifier_ops, list) {
69 if (!try_module_get(ops->owner))
70 continue;
71 err = ops->fib_dump(net, nb, extack);
72 module_put(ops->owner);
73 if (err)
74 goto unlock;
75 }
76
77unlock:
78 rcu_read_unlock();
79
80 return err;
81}
82
83static bool fib_dump_is_consistent(struct net *net, struct notifier_block *nb,
84 void (*cb)(struct notifier_block *nb),
85 unsigned int fib_seq)
86{
87 struct fib_notifier_net *fn_net = net_generic(net, fib_notifier_net_id);
88
89 atomic_notifier_chain_register(&fn_net->fib_chain, nb);
90 if (fib_seq == fib_seq_sum(net))
91 return true;
92 atomic_notifier_chain_unregister(&fn_net->fib_chain, nb);
93 if (cb)
94 cb(nb);
95 return false;
96}
97
98#define FIB_DUMP_MAX_RETRIES 5
99int register_fib_notifier(struct net *net, struct notifier_block *nb,
100 void (*cb)(struct notifier_block *nb),
101 struct netlink_ext_ack *extack)
102{
103 int retries = 0;
104 int err;
105
106 do {
107 unsigned int fib_seq = fib_seq_sum(net);
108
109 err = fib_net_dump(net, nb, extack);
110 if (err)
111 return err;
112
113 if (fib_dump_is_consistent(net, nb, cb, fib_seq))
114 return 0;
115 } while (++retries < FIB_DUMP_MAX_RETRIES);
116
117 return -EBUSY;
118}
119EXPORT_SYMBOL(register_fib_notifier);
120
121int unregister_fib_notifier(struct net *net, struct notifier_block *nb)
122{
123 struct fib_notifier_net *fn_net = net_generic(net, fib_notifier_net_id);
124
125 return atomic_notifier_chain_unregister(&fn_net->fib_chain, nb);
126}
127EXPORT_SYMBOL(unregister_fib_notifier);
128
129static int __fib_notifier_ops_register(struct fib_notifier_ops *ops,
130 struct net *net)
131{
132 struct fib_notifier_net *fn_net = net_generic(net, fib_notifier_net_id);
133 struct fib_notifier_ops *o;
134
135 list_for_each_entry(o, &fn_net->fib_notifier_ops, list)
136 if (ops->family == o->family)
137 return -EEXIST;
138 list_add_tail_rcu(&ops->list, &fn_net->fib_notifier_ops);
139 return 0;
140}
141
142struct fib_notifier_ops *
143fib_notifier_ops_register(const struct fib_notifier_ops *tmpl, struct net *net)
144{
145 struct fib_notifier_ops *ops;
146 int err;
147
148 ops = kmemdup(tmpl, sizeof(*ops), GFP_KERNEL);
149 if (!ops)
150 return ERR_PTR(-ENOMEM);
151
152 err = __fib_notifier_ops_register(ops, net);
153 if (err)
154 goto err_register;
155
156 return ops;
157
158err_register:
159 kfree(ops);
160 return ERR_PTR(err);
161}
162EXPORT_SYMBOL(fib_notifier_ops_register);
163
164void fib_notifier_ops_unregister(struct fib_notifier_ops *ops)
165{
166 list_del_rcu(&ops->list);
167 kfree_rcu(ops, rcu);
168}
169EXPORT_SYMBOL(fib_notifier_ops_unregister);
170
171static int __net_init fib_notifier_net_init(struct net *net)
172{
173 struct fib_notifier_net *fn_net = net_generic(net, fib_notifier_net_id);
174
175 INIT_LIST_HEAD(&fn_net->fib_notifier_ops);
176 ATOMIC_INIT_NOTIFIER_HEAD(&fn_net->fib_chain);
177 return 0;
178}
179
180static void __net_exit fib_notifier_net_exit(struct net *net)
181{
182 struct fib_notifier_net *fn_net = net_generic(net, fib_notifier_net_id);
183
184 WARN_ON_ONCE(!list_empty(&fn_net->fib_notifier_ops));
185}
186
187static struct pernet_operations fib_notifier_net_ops = {
188 .init = fib_notifier_net_init,
189 .exit = fib_notifier_net_exit,
190 .id = &fib_notifier_net_id,
191 .size = sizeof(struct fib_notifier_net),
192};
193
194static int __init fib_notifier_init(void)
195{
196 return register_pernet_subsys(&fib_notifier_net_ops);
197}
198
199subsys_initcall(fib_notifier_init);
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>
9
10static ATOMIC_NOTIFIER_HEAD(fib_chain);
11
12int call_fib_notifier(struct notifier_block *nb, struct net *net,
13 enum fib_event_type event_type,
14 struct fib_notifier_info *info)
15{
16 int err;
17
18 info->net = net;
19 err = nb->notifier_call(nb, event_type, info);
20 return notifier_to_errno(err);
21}
22EXPORT_SYMBOL(call_fib_notifier);
23
24int call_fib_notifiers(struct net *net, enum fib_event_type event_type,
25 struct fib_notifier_info *info)
26{
27 int err;
28
29 info->net = net;
30 err = atomic_notifier_call_chain(&fib_chain, event_type, info);
31 return notifier_to_errno(err);
32}
33EXPORT_SYMBOL(call_fib_notifiers);
34
35static unsigned int fib_seq_sum(void)
36{
37 struct fib_notifier_ops *ops;
38 unsigned int fib_seq = 0;
39 struct net *net;
40
41 rtnl_lock();
42 down_read(&net_rwsem);
43 for_each_net(net) {
44 rcu_read_lock();
45 list_for_each_entry_rcu(ops, &net->fib_notifier_ops, list) {
46 if (!try_module_get(ops->owner))
47 continue;
48 fib_seq += ops->fib_seq_read(net);
49 module_put(ops->owner);
50 }
51 rcu_read_unlock();
52 }
53 up_read(&net_rwsem);
54 rtnl_unlock();
55
56 return fib_seq;
57}
58
59static int fib_net_dump(struct net *net, struct notifier_block *nb)
60{
61 struct fib_notifier_ops *ops;
62
63 list_for_each_entry_rcu(ops, &net->fib_notifier_ops, list) {
64 int err;
65
66 if (!try_module_get(ops->owner))
67 continue;
68 err = ops->fib_dump(net, nb);
69 module_put(ops->owner);
70 if (err)
71 return err;
72 }
73
74 return 0;
75}
76
77static bool fib_dump_is_consistent(struct notifier_block *nb,
78 void (*cb)(struct notifier_block *nb),
79 unsigned int fib_seq)
80{
81 atomic_notifier_chain_register(&fib_chain, nb);
82 if (fib_seq == fib_seq_sum())
83 return true;
84 atomic_notifier_chain_unregister(&fib_chain, nb);
85 if (cb)
86 cb(nb);
87 return false;
88}
89
90#define FIB_DUMP_MAX_RETRIES 5
91int register_fib_notifier(struct notifier_block *nb,
92 void (*cb)(struct notifier_block *nb))
93{
94 int retries = 0;
95 int err;
96
97 do {
98 unsigned int fib_seq = fib_seq_sum();
99 struct net *net;
100
101 rcu_read_lock();
102 for_each_net_rcu(net) {
103 err = fib_net_dump(net, nb);
104 if (err)
105 goto err_fib_net_dump;
106 }
107 rcu_read_unlock();
108
109 if (fib_dump_is_consistent(nb, cb, fib_seq))
110 return 0;
111 } while (++retries < FIB_DUMP_MAX_RETRIES);
112
113 return -EBUSY;
114
115err_fib_net_dump:
116 rcu_read_unlock();
117 return err;
118}
119EXPORT_SYMBOL(register_fib_notifier);
120
121int unregister_fib_notifier(struct notifier_block *nb)
122{
123 return atomic_notifier_chain_unregister(&fib_chain, nb);
124}
125EXPORT_SYMBOL(unregister_fib_notifier);
126
127static int __fib_notifier_ops_register(struct fib_notifier_ops *ops,
128 struct net *net)
129{
130 struct fib_notifier_ops *o;
131
132 list_for_each_entry(o, &net->fib_notifier_ops, list)
133 if (ops->family == o->family)
134 return -EEXIST;
135 list_add_tail_rcu(&ops->list, &net->fib_notifier_ops);
136 return 0;
137}
138
139struct fib_notifier_ops *
140fib_notifier_ops_register(const struct fib_notifier_ops *tmpl, struct net *net)
141{
142 struct fib_notifier_ops *ops;
143 int err;
144
145 ops = kmemdup(tmpl, sizeof(*ops), GFP_KERNEL);
146 if (!ops)
147 return ERR_PTR(-ENOMEM);
148
149 err = __fib_notifier_ops_register(ops, net);
150 if (err)
151 goto err_register;
152
153 return ops;
154
155err_register:
156 kfree(ops);
157 return ERR_PTR(err);
158}
159EXPORT_SYMBOL(fib_notifier_ops_register);
160
161void fib_notifier_ops_unregister(struct fib_notifier_ops *ops)
162{
163 list_del_rcu(&ops->list);
164 kfree_rcu(ops, rcu);
165}
166EXPORT_SYMBOL(fib_notifier_ops_unregister);
167
168static int __net_init fib_notifier_net_init(struct net *net)
169{
170 INIT_LIST_HEAD(&net->fib_notifier_ops);
171 return 0;
172}
173
174static void __net_exit fib_notifier_net_exit(struct net *net)
175{
176 WARN_ON_ONCE(!list_empty(&net->fib_notifier_ops));
177}
178
179static struct pernet_operations fib_notifier_net_ops = {
180 .init = fib_notifier_net_init,
181 .exit = fib_notifier_net_exit,
182};
183
184static int __init fib_notifier_init(void)
185{
186 return register_pernet_subsys(&fib_notifier_net_ops);
187}
188
189subsys_initcall(fib_notifier_init);