Commit | Line | Data |
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04b1d4e5 IS |
1 | #include <linux/rtnetlink.h> |
2 | #include <linux/notifier.h> | |
3 | #include <linux/rcupdate.h> | |
4 | #include <linux/kernel.h> | |
864150df | 5 | #include <linux/module.h> |
04b1d4e5 IS |
6 | #include <linux/init.h> |
7 | #include <net/net_namespace.h> | |
3dd97a08 | 8 | #include <net/netns/generic.h> |
04b1d4e5 IS |
9 | #include <net/fib_notifier.h> |
10 | ||
3dd97a08 JP |
11 | static unsigned int fib_notifier_net_id; |
12 | ||
13 | struct fib_notifier_net { | |
14 | struct list_head fib_notifier_ops; | |
15 | }; | |
16 | ||
04b1d4e5 IS |
17 | static ATOMIC_NOTIFIER_HEAD(fib_chain); |
18 | ||
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) | |
22 | { | |
c30d9356 DA |
23 | int err; |
24 | ||
04b1d4e5 | 25 | info->net = net; |
c30d9356 DA |
26 | err = nb->notifier_call(nb, event_type, info); |
27 | return notifier_to_errno(err); | |
04b1d4e5 IS |
28 | } |
29 | EXPORT_SYMBOL(call_fib_notifier); | |
30 | ||
31 | int call_fib_notifiers(struct net *net, enum fib_event_type event_type, | |
32 | struct fib_notifier_info *info) | |
33 | { | |
c30d9356 DA |
34 | int err; |
35 | ||
04b1d4e5 | 36 | info->net = net; |
c30d9356 DA |
37 | err = atomic_notifier_call_chain(&fib_chain, event_type, info); |
38 | return notifier_to_errno(err); | |
04b1d4e5 IS |
39 | } |
40 | EXPORT_SYMBOL(call_fib_notifiers); | |
41 | ||
42 | static unsigned int fib_seq_sum(void) | |
43 | { | |
3dd97a08 | 44 | struct fib_notifier_net *fn_net; |
04b1d4e5 IS |
45 | struct fib_notifier_ops *ops; |
46 | unsigned int fib_seq = 0; | |
47 | struct net *net; | |
48 | ||
49 | rtnl_lock(); | |
f0b07bb1 | 50 | down_read(&net_rwsem); |
04b1d4e5 | 51 | for_each_net(net) { |
3dd97a08 | 52 | fn_net = net_generic(net, fib_notifier_net_id); |
11bf284f | 53 | rcu_read_lock(); |
3dd97a08 | 54 | list_for_each_entry_rcu(ops, &fn_net->fib_notifier_ops, list) { |
864150df IS |
55 | if (!try_module_get(ops->owner)) |
56 | continue; | |
04b1d4e5 | 57 | fib_seq += ops->fib_seq_read(net); |
864150df IS |
58 | module_put(ops->owner); |
59 | } | |
11bf284f | 60 | rcu_read_unlock(); |
04b1d4e5 | 61 | } |
f0b07bb1 | 62 | up_read(&net_rwsem); |
04b1d4e5 IS |
63 | rtnl_unlock(); |
64 | ||
65 | return fib_seq; | |
66 | } | |
67 | ||
68 | static int fib_net_dump(struct net *net, struct notifier_block *nb) | |
69 | { | |
3dd97a08 | 70 | struct fib_notifier_net *fn_net = net_generic(net, fib_notifier_net_id); |
04b1d4e5 IS |
71 | struct fib_notifier_ops *ops; |
72 | ||
3dd97a08 | 73 | list_for_each_entry_rcu(ops, &fn_net->fib_notifier_ops, list) { |
864150df | 74 | int err; |
04b1d4e5 | 75 | |
864150df IS |
76 | if (!try_module_get(ops->owner)) |
77 | continue; | |
78 | err = ops->fib_dump(net, nb); | |
79 | module_put(ops->owner); | |
04b1d4e5 IS |
80 | if (err) |
81 | return err; | |
82 | } | |
83 | ||
84 | return 0; | |
85 | } | |
86 | ||
87 | static bool fib_dump_is_consistent(struct notifier_block *nb, | |
88 | void (*cb)(struct notifier_block *nb), | |
89 | unsigned int fib_seq) | |
90 | { | |
91 | atomic_notifier_chain_register(&fib_chain, nb); | |
92 | if (fib_seq == fib_seq_sum()) | |
93 | return true; | |
94 | atomic_notifier_chain_unregister(&fib_chain, nb); | |
95 | if (cb) | |
96 | cb(nb); | |
97 | return false; | |
98 | } | |
99 | ||
100 | #define FIB_DUMP_MAX_RETRIES 5 | |
101 | int register_fib_notifier(struct notifier_block *nb, | |
102 | void (*cb)(struct notifier_block *nb)) | |
103 | { | |
104 | int retries = 0; | |
105 | int err; | |
106 | ||
107 | do { | |
108 | unsigned int fib_seq = fib_seq_sum(); | |
109 | struct net *net; | |
110 | ||
111 | rcu_read_lock(); | |
112 | for_each_net_rcu(net) { | |
113 | err = fib_net_dump(net, nb); | |
114 | if (err) | |
115 | goto err_fib_net_dump; | |
116 | } | |
117 | rcu_read_unlock(); | |
118 | ||
119 | if (fib_dump_is_consistent(nb, cb, fib_seq)) | |
120 | return 0; | |
121 | } while (++retries < FIB_DUMP_MAX_RETRIES); | |
122 | ||
123 | return -EBUSY; | |
124 | ||
125 | err_fib_net_dump: | |
126 | rcu_read_unlock(); | |
127 | return err; | |
128 | } | |
129 | EXPORT_SYMBOL(register_fib_notifier); | |
130 | ||
131 | int unregister_fib_notifier(struct notifier_block *nb) | |
132 | { | |
133 | return atomic_notifier_chain_unregister(&fib_chain, nb); | |
134 | } | |
135 | EXPORT_SYMBOL(unregister_fib_notifier); | |
136 | ||
137 | static int __fib_notifier_ops_register(struct fib_notifier_ops *ops, | |
138 | struct net *net) | |
139 | { | |
3dd97a08 | 140 | struct fib_notifier_net *fn_net = net_generic(net, fib_notifier_net_id); |
04b1d4e5 IS |
141 | struct fib_notifier_ops *o; |
142 | ||
3dd97a08 | 143 | list_for_each_entry(o, &fn_net->fib_notifier_ops, list) |
04b1d4e5 IS |
144 | if (ops->family == o->family) |
145 | return -EEXIST; | |
3dd97a08 | 146 | list_add_tail_rcu(&ops->list, &fn_net->fib_notifier_ops); |
04b1d4e5 IS |
147 | return 0; |
148 | } | |
149 | ||
150 | struct fib_notifier_ops * | |
151 | fib_notifier_ops_register(const struct fib_notifier_ops *tmpl, struct net *net) | |
152 | { | |
153 | struct fib_notifier_ops *ops; | |
154 | int err; | |
155 | ||
156 | ops = kmemdup(tmpl, sizeof(*ops), GFP_KERNEL); | |
157 | if (!ops) | |
158 | return ERR_PTR(-ENOMEM); | |
159 | ||
160 | err = __fib_notifier_ops_register(ops, net); | |
161 | if (err) | |
162 | goto err_register; | |
163 | ||
164 | return ops; | |
165 | ||
166 | err_register: | |
167 | kfree(ops); | |
168 | return ERR_PTR(err); | |
169 | } | |
170 | EXPORT_SYMBOL(fib_notifier_ops_register); | |
171 | ||
172 | void fib_notifier_ops_unregister(struct fib_notifier_ops *ops) | |
173 | { | |
174 | list_del_rcu(&ops->list); | |
175 | kfree_rcu(ops, rcu); | |
176 | } | |
177 | EXPORT_SYMBOL(fib_notifier_ops_unregister); | |
178 | ||
179 | static int __net_init fib_notifier_net_init(struct net *net) | |
180 | { | |
3dd97a08 JP |
181 | struct fib_notifier_net *fn_net = net_generic(net, fib_notifier_net_id); |
182 | ||
183 | INIT_LIST_HEAD(&fn_net->fib_notifier_ops); | |
04b1d4e5 IS |
184 | return 0; |
185 | } | |
186 | ||
0b6f5955 VA |
187 | static void __net_exit fib_notifier_net_exit(struct net *net) |
188 | { | |
3dd97a08 JP |
189 | struct fib_notifier_net *fn_net = net_generic(net, fib_notifier_net_id); |
190 | ||
191 | WARN_ON_ONCE(!list_empty(&fn_net->fib_notifier_ops)); | |
0b6f5955 VA |
192 | } |
193 | ||
04b1d4e5 IS |
194 | static struct pernet_operations fib_notifier_net_ops = { |
195 | .init = fib_notifier_net_init, | |
0b6f5955 | 196 | .exit = fib_notifier_net_exit, |
3dd97a08 JP |
197 | .id = &fib_notifier_net_id, |
198 | .size = sizeof(struct fib_notifier_net), | |
04b1d4e5 IS |
199 | }; |
200 | ||
201 | static int __init fib_notifier_init(void) | |
202 | { | |
203 | return register_pernet_subsys(&fib_notifier_net_ops); | |
204 | } | |
205 | ||
206 | subsys_initcall(fib_notifier_init); |