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5f256bec EB |
1 | #include <linux/workqueue.h> |
2 | #include <linux/rtnetlink.h> | |
3 | #include <linux/cache.h> | |
4 | #include <linux/slab.h> | |
5 | #include <linux/list.h> | |
6 | #include <linux/delay.h> | |
9dd776b6 | 7 | #include <linux/sched.h> |
5f256bec EB |
8 | #include <net/net_namespace.h> |
9 | ||
10 | /* | |
11 | * Our network namespace constructor/destructor lists | |
12 | */ | |
13 | ||
14 | static LIST_HEAD(pernet_list); | |
15 | static struct list_head *first_device = &pernet_list; | |
16 | static DEFINE_MUTEX(net_mutex); | |
17 | ||
5f256bec EB |
18 | LIST_HEAD(net_namespace_list); |
19 | ||
20 | static struct kmem_cache *net_cachep; | |
21 | ||
22 | struct net init_net; | |
23 | EXPORT_SYMBOL_GPL(init_net); | |
24 | ||
5f256bec EB |
25 | /* |
26 | * setup_net runs the initializers for the network namespace object. | |
27 | */ | |
1a2ee93d | 28 | static __net_init int setup_net(struct net *net) |
5f256bec EB |
29 | { |
30 | /* Must be called with net_mutex held */ | |
31 | struct pernet_operations *ops; | |
5f256bec EB |
32 | int error; |
33 | ||
5f256bec EB |
34 | atomic_set(&net->count, 1); |
35 | atomic_set(&net->use_count, 0); | |
36 | ||
37 | error = 0; | |
768f3591 | 38 | list_for_each_entry(ops, &pernet_list, list) { |
5f256bec EB |
39 | if (ops->init) { |
40 | error = ops->init(net); | |
41 | if (error < 0) | |
42 | goto out_undo; | |
43 | } | |
44 | } | |
45 | out: | |
46 | return error; | |
768f3591 | 47 | |
5f256bec EB |
48 | out_undo: |
49 | /* Walk through the list backwards calling the exit functions | |
50 | * for the pernet modules whose init functions did not fail. | |
51 | */ | |
768f3591 | 52 | list_for_each_entry_continue_reverse(ops, &pernet_list, list) { |
5f256bec EB |
53 | if (ops->exit) |
54 | ops->exit(net); | |
55 | } | |
310928d9 DL |
56 | |
57 | rcu_barrier(); | |
5f256bec EB |
58 | goto out; |
59 | } | |
60 | ||
6a1a3b9f PE |
61 | #ifdef CONFIG_NET_NS |
62 | static struct net *net_alloc(void) | |
63 | { | |
64 | return kmem_cache_zalloc(net_cachep, GFP_KERNEL); | |
65 | } | |
66 | ||
9dd776b6 EB |
67 | struct net *copy_net_ns(unsigned long flags, struct net *old_net) |
68 | { | |
69 | struct net *new_net = NULL; | |
70 | int err; | |
71 | ||
72 | get_net(old_net); | |
73 | ||
74 | if (!(flags & CLONE_NEWNET)) | |
75 | return old_net; | |
76 | ||
9dd776b6 EB |
77 | err = -ENOMEM; |
78 | new_net = net_alloc(); | |
79 | if (!new_net) | |
80 | goto out; | |
81 | ||
82 | mutex_lock(&net_mutex); | |
83 | err = setup_net(new_net); | |
84 | if (err) | |
85 | goto out_unlock; | |
86 | ||
f4618d39 | 87 | rtnl_lock(); |
9dd776b6 | 88 | list_add_tail(&new_net->list, &net_namespace_list); |
f4618d39 | 89 | rtnl_unlock(); |
9dd776b6 EB |
90 | |
91 | ||
92 | out_unlock: | |
93 | mutex_unlock(&net_mutex); | |
94 | out: | |
95 | put_net(old_net); | |
96 | if (err) { | |
97 | net_free(new_net); | |
98 | new_net = ERR_PTR(err); | |
99 | } | |
100 | return new_net; | |
101 | } | |
102 | ||
6a1a3b9f PE |
103 | static void net_free(struct net *net) |
104 | { | |
105 | if (!net) | |
106 | return; | |
107 | ||
108 | if (unlikely(atomic_read(&net->use_count) != 0)) { | |
109 | printk(KERN_EMERG "network namespace not free! Usage: %d\n", | |
110 | atomic_read(&net->use_count)); | |
111 | return; | |
112 | } | |
113 | ||
114 | kmem_cache_free(net_cachep, net); | |
115 | } | |
116 | ||
117 | static void cleanup_net(struct work_struct *work) | |
118 | { | |
119 | struct pernet_operations *ops; | |
120 | struct net *net; | |
121 | ||
122 | net = container_of(work, struct net, work); | |
123 | ||
124 | mutex_lock(&net_mutex); | |
125 | ||
126 | /* Don't let anyone else find us. */ | |
127 | rtnl_lock(); | |
128 | list_del(&net->list); | |
129 | rtnl_unlock(); | |
130 | ||
131 | /* Run all of the network namespace exit methods */ | |
132 | list_for_each_entry_reverse(ops, &pernet_list, list) { | |
133 | if (ops->exit) | |
134 | ops->exit(net); | |
135 | } | |
136 | ||
137 | mutex_unlock(&net_mutex); | |
138 | ||
139 | /* Ensure there are no outstanding rcu callbacks using this | |
140 | * network namespace. | |
141 | */ | |
142 | rcu_barrier(); | |
143 | ||
144 | /* Finally it is safe to free my network namespace structure */ | |
145 | net_free(net); | |
146 | } | |
147 | ||
148 | void __put_net(struct net *net) | |
149 | { | |
150 | /* Cleanup the network namespace in process context */ | |
151 | INIT_WORK(&net->work, cleanup_net); | |
152 | schedule_work(&net->work); | |
153 | } | |
154 | EXPORT_SYMBOL_GPL(__put_net); | |
155 | ||
156 | #else | |
157 | struct net *copy_net_ns(unsigned long flags, struct net *old_net) | |
158 | { | |
159 | if (flags & CLONE_NEWNET) | |
160 | return ERR_PTR(-EINVAL); | |
161 | return old_net; | |
162 | } | |
163 | #endif | |
164 | ||
5f256bec EB |
165 | static int __init net_ns_init(void) |
166 | { | |
167 | int err; | |
168 | ||
169 | printk(KERN_INFO "net_namespace: %zd bytes\n", sizeof(struct net)); | |
170 | net_cachep = kmem_cache_create("net_namespace", sizeof(struct net), | |
171 | SMP_CACHE_BYTES, | |
172 | SLAB_PANIC, NULL); | |
173 | mutex_lock(&net_mutex); | |
174 | err = setup_net(&init_net); | |
175 | ||
f4618d39 | 176 | rtnl_lock(); |
5f256bec | 177 | list_add_tail(&init_net.list, &net_namespace_list); |
f4618d39 | 178 | rtnl_unlock(); |
5f256bec EB |
179 | |
180 | mutex_unlock(&net_mutex); | |
181 | if (err) | |
182 | panic("Could not setup the initial network namespace"); | |
183 | ||
184 | return 0; | |
185 | } | |
186 | ||
187 | pure_initcall(net_ns_init); | |
188 | ||
189 | static int register_pernet_operations(struct list_head *list, | |
190 | struct pernet_operations *ops) | |
191 | { | |
192 | struct net *net, *undo_net; | |
193 | int error; | |
194 | ||
5f256bec | 195 | list_add_tail(&ops->list, list); |
1dba323b PE |
196 | if (ops->init) { |
197 | for_each_net(net) { | |
5f256bec EB |
198 | error = ops->init(net); |
199 | if (error) | |
200 | goto out_undo; | |
201 | } | |
202 | } | |
1dba323b | 203 | return 0; |
5f256bec EB |
204 | |
205 | out_undo: | |
206 | /* If I have an error cleanup all namespaces I initialized */ | |
207 | list_del(&ops->list); | |
1dba323b PE |
208 | if (ops->exit) { |
209 | for_each_net(undo_net) { | |
210 | if (undo_net == net) | |
211 | goto undone; | |
5f256bec | 212 | ops->exit(undo_net); |
1dba323b | 213 | } |
5f256bec EB |
214 | } |
215 | undone: | |
1dba323b | 216 | return error; |
5f256bec EB |
217 | } |
218 | ||
219 | static void unregister_pernet_operations(struct pernet_operations *ops) | |
220 | { | |
221 | struct net *net; | |
222 | ||
223 | list_del(&ops->list); | |
1dba323b PE |
224 | if (ops->exit) |
225 | for_each_net(net) | |
5f256bec EB |
226 | ops->exit(net); |
227 | } | |
228 | ||
229 | /** | |
230 | * register_pernet_subsys - register a network namespace subsystem | |
231 | * @ops: pernet operations structure for the subsystem | |
232 | * | |
233 | * Register a subsystem which has init and exit functions | |
234 | * that are called when network namespaces are created and | |
235 | * destroyed respectively. | |
236 | * | |
237 | * When registered all network namespace init functions are | |
238 | * called for every existing network namespace. Allowing kernel | |
239 | * modules to have a race free view of the set of network namespaces. | |
240 | * | |
241 | * When a new network namespace is created all of the init | |
242 | * methods are called in the order in which they were registered. | |
243 | * | |
244 | * When a network namespace is destroyed all of the exit methods | |
245 | * are called in the reverse of the order with which they were | |
246 | * registered. | |
247 | */ | |
248 | int register_pernet_subsys(struct pernet_operations *ops) | |
249 | { | |
250 | int error; | |
251 | mutex_lock(&net_mutex); | |
252 | error = register_pernet_operations(first_device, ops); | |
253 | mutex_unlock(&net_mutex); | |
254 | return error; | |
255 | } | |
256 | EXPORT_SYMBOL_GPL(register_pernet_subsys); | |
257 | ||
258 | /** | |
259 | * unregister_pernet_subsys - unregister a network namespace subsystem | |
260 | * @ops: pernet operations structure to manipulate | |
261 | * | |
262 | * Remove the pernet operations structure from the list to be | |
263 | * used when network namespaces are created or destoryed. In | |
264 | * addition run the exit method for all existing network | |
265 | * namespaces. | |
266 | */ | |
267 | void unregister_pernet_subsys(struct pernet_operations *module) | |
268 | { | |
269 | mutex_lock(&net_mutex); | |
270 | unregister_pernet_operations(module); | |
271 | mutex_unlock(&net_mutex); | |
272 | } | |
273 | EXPORT_SYMBOL_GPL(unregister_pernet_subsys); | |
274 | ||
275 | /** | |
276 | * register_pernet_device - register a network namespace device | |
277 | * @ops: pernet operations structure for the subsystem | |
278 | * | |
279 | * Register a device which has init and exit functions | |
280 | * that are called when network namespaces are created and | |
281 | * destroyed respectively. | |
282 | * | |
283 | * When registered all network namespace init functions are | |
284 | * called for every existing network namespace. Allowing kernel | |
285 | * modules to have a race free view of the set of network namespaces. | |
286 | * | |
287 | * When a new network namespace is created all of the init | |
288 | * methods are called in the order in which they were registered. | |
289 | * | |
290 | * When a network namespace is destroyed all of the exit methods | |
291 | * are called in the reverse of the order with which they were | |
292 | * registered. | |
293 | */ | |
294 | int register_pernet_device(struct pernet_operations *ops) | |
295 | { | |
296 | int error; | |
297 | mutex_lock(&net_mutex); | |
298 | error = register_pernet_operations(&pernet_list, ops); | |
299 | if (!error && (first_device == &pernet_list)) | |
300 | first_device = &ops->list; | |
301 | mutex_unlock(&net_mutex); | |
302 | return error; | |
303 | } | |
304 | EXPORT_SYMBOL_GPL(register_pernet_device); | |
305 | ||
306 | /** | |
307 | * unregister_pernet_device - unregister a network namespace netdevice | |
308 | * @ops: pernet operations structure to manipulate | |
309 | * | |
310 | * Remove the pernet operations structure from the list to be | |
311 | * used when network namespaces are created or destoryed. In | |
312 | * addition run the exit method for all existing network | |
313 | * namespaces. | |
314 | */ | |
315 | void unregister_pernet_device(struct pernet_operations *ops) | |
316 | { | |
317 | mutex_lock(&net_mutex); | |
318 | if (&ops->list == first_device) | |
319 | first_device = first_device->next; | |
320 | unregister_pernet_operations(ops); | |
321 | mutex_unlock(&net_mutex); | |
322 | } | |
323 | EXPORT_SYMBOL_GPL(unregister_pernet_device); |