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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 | static struct net *net_alloc(void) |
26 | { | |
32f0c4cb | 27 | return kmem_cache_zalloc(net_cachep, GFP_KERNEL); |
5f256bec EB |
28 | } |
29 | ||
30 | static void net_free(struct net *net) | |
31 | { | |
32 | if (!net) | |
33 | return; | |
34 | ||
35 | if (unlikely(atomic_read(&net->use_count) != 0)) { | |
36 | printk(KERN_EMERG "network namespace not free! Usage: %d\n", | |
37 | atomic_read(&net->use_count)); | |
38 | return; | |
39 | } | |
40 | ||
41 | kmem_cache_free(net_cachep, net); | |
42 | } | |
43 | ||
44 | static void cleanup_net(struct work_struct *work) | |
45 | { | |
46 | struct pernet_operations *ops; | |
5f256bec EB |
47 | struct net *net; |
48 | ||
49 | net = container_of(work, struct net, work); | |
50 | ||
51 | mutex_lock(&net_mutex); | |
52 | ||
53 | /* Don't let anyone else find us. */ | |
f4618d39 | 54 | rtnl_lock(); |
5f256bec | 55 | list_del(&net->list); |
f4618d39 | 56 | rtnl_unlock(); |
5f256bec EB |
57 | |
58 | /* Run all of the network namespace exit methods */ | |
768f3591 | 59 | list_for_each_entry_reverse(ops, &pernet_list, list) { |
5f256bec EB |
60 | if (ops->exit) |
61 | ops->exit(net); | |
62 | } | |
63 | ||
64 | mutex_unlock(&net_mutex); | |
65 | ||
66 | /* Ensure there are no outstanding rcu callbacks using this | |
67 | * network namespace. | |
68 | */ | |
69 | rcu_barrier(); | |
70 | ||
71 | /* Finally it is safe to free my network namespace structure */ | |
72 | net_free(net); | |
73 | } | |
74 | ||
75 | ||
76 | void __put_net(struct net *net) | |
77 | { | |
78 | /* Cleanup the network namespace in process context */ | |
79 | INIT_WORK(&net->work, cleanup_net); | |
80 | schedule_work(&net->work); | |
81 | } | |
82 | EXPORT_SYMBOL_GPL(__put_net); | |
83 | ||
84 | /* | |
85 | * setup_net runs the initializers for the network namespace object. | |
86 | */ | |
87 | static int setup_net(struct net *net) | |
88 | { | |
89 | /* Must be called with net_mutex held */ | |
90 | struct pernet_operations *ops; | |
5f256bec EB |
91 | int error; |
92 | ||
5f256bec EB |
93 | atomic_set(&net->count, 1); |
94 | atomic_set(&net->use_count, 0); | |
95 | ||
96 | error = 0; | |
768f3591 | 97 | list_for_each_entry(ops, &pernet_list, list) { |
5f256bec EB |
98 | if (ops->init) { |
99 | error = ops->init(net); | |
100 | if (error < 0) | |
101 | goto out_undo; | |
102 | } | |
103 | } | |
104 | out: | |
105 | return error; | |
768f3591 | 106 | |
5f256bec EB |
107 | out_undo: |
108 | /* Walk through the list backwards calling the exit functions | |
109 | * for the pernet modules whose init functions did not fail. | |
110 | */ | |
768f3591 | 111 | list_for_each_entry_continue_reverse(ops, &pernet_list, list) { |
5f256bec EB |
112 | if (ops->exit) |
113 | ops->exit(net); | |
114 | } | |
310928d9 DL |
115 | |
116 | rcu_barrier(); | |
5f256bec EB |
117 | goto out; |
118 | } | |
119 | ||
9dd776b6 EB |
120 | struct net *copy_net_ns(unsigned long flags, struct net *old_net) |
121 | { | |
122 | struct net *new_net = NULL; | |
123 | int err; | |
124 | ||
125 | get_net(old_net); | |
126 | ||
127 | if (!(flags & CLONE_NEWNET)) | |
128 | return old_net; | |
129 | ||
130 | #ifndef CONFIG_NET_NS | |
131 | return ERR_PTR(-EINVAL); | |
132 | #endif | |
133 | ||
134 | err = -ENOMEM; | |
135 | new_net = net_alloc(); | |
136 | if (!new_net) | |
137 | goto out; | |
138 | ||
139 | mutex_lock(&net_mutex); | |
140 | err = setup_net(new_net); | |
141 | if (err) | |
142 | goto out_unlock; | |
143 | ||
f4618d39 | 144 | rtnl_lock(); |
9dd776b6 | 145 | list_add_tail(&new_net->list, &net_namespace_list); |
f4618d39 | 146 | rtnl_unlock(); |
9dd776b6 EB |
147 | |
148 | ||
149 | out_unlock: | |
150 | mutex_unlock(&net_mutex); | |
151 | out: | |
152 | put_net(old_net); | |
153 | if (err) { | |
154 | net_free(new_net); | |
155 | new_net = ERR_PTR(err); | |
156 | } | |
157 | return new_net; | |
158 | } | |
159 | ||
5f256bec EB |
160 | static int __init net_ns_init(void) |
161 | { | |
162 | int err; | |
163 | ||
164 | printk(KERN_INFO "net_namespace: %zd bytes\n", sizeof(struct net)); | |
165 | net_cachep = kmem_cache_create("net_namespace", sizeof(struct net), | |
166 | SMP_CACHE_BYTES, | |
167 | SLAB_PANIC, NULL); | |
168 | mutex_lock(&net_mutex); | |
169 | err = setup_net(&init_net); | |
170 | ||
f4618d39 | 171 | rtnl_lock(); |
5f256bec | 172 | list_add_tail(&init_net.list, &net_namespace_list); |
f4618d39 | 173 | rtnl_unlock(); |
5f256bec EB |
174 | |
175 | mutex_unlock(&net_mutex); | |
176 | if (err) | |
177 | panic("Could not setup the initial network namespace"); | |
178 | ||
179 | return 0; | |
180 | } | |
181 | ||
182 | pure_initcall(net_ns_init); | |
183 | ||
184 | static int register_pernet_operations(struct list_head *list, | |
185 | struct pernet_operations *ops) | |
186 | { | |
187 | struct net *net, *undo_net; | |
188 | int error; | |
189 | ||
190 | error = 0; | |
191 | list_add_tail(&ops->list, list); | |
192 | for_each_net(net) { | |
193 | if (ops->init) { | |
194 | error = ops->init(net); | |
195 | if (error) | |
196 | goto out_undo; | |
197 | } | |
198 | } | |
199 | out: | |
200 | return error; | |
201 | ||
202 | out_undo: | |
203 | /* If I have an error cleanup all namespaces I initialized */ | |
204 | list_del(&ops->list); | |
205 | for_each_net(undo_net) { | |
206 | if (undo_net == net) | |
207 | goto undone; | |
208 | if (ops->exit) | |
209 | ops->exit(undo_net); | |
210 | } | |
211 | undone: | |
212 | goto out; | |
213 | } | |
214 | ||
215 | static void unregister_pernet_operations(struct pernet_operations *ops) | |
216 | { | |
217 | struct net *net; | |
218 | ||
219 | list_del(&ops->list); | |
220 | for_each_net(net) | |
221 | if (ops->exit) | |
222 | ops->exit(net); | |
223 | } | |
224 | ||
225 | /** | |
226 | * register_pernet_subsys - register a network namespace subsystem | |
227 | * @ops: pernet operations structure for the subsystem | |
228 | * | |
229 | * Register a subsystem which has init and exit functions | |
230 | * that are called when network namespaces are created and | |
231 | * destroyed respectively. | |
232 | * | |
233 | * When registered all network namespace init functions are | |
234 | * called for every existing network namespace. Allowing kernel | |
235 | * modules to have a race free view of the set of network namespaces. | |
236 | * | |
237 | * When a new network namespace is created all of the init | |
238 | * methods are called in the order in which they were registered. | |
239 | * | |
240 | * When a network namespace is destroyed all of the exit methods | |
241 | * are called in the reverse of the order with which they were | |
242 | * registered. | |
243 | */ | |
244 | int register_pernet_subsys(struct pernet_operations *ops) | |
245 | { | |
246 | int error; | |
247 | mutex_lock(&net_mutex); | |
248 | error = register_pernet_operations(first_device, ops); | |
249 | mutex_unlock(&net_mutex); | |
250 | return error; | |
251 | } | |
252 | EXPORT_SYMBOL_GPL(register_pernet_subsys); | |
253 | ||
254 | /** | |
255 | * unregister_pernet_subsys - unregister a network namespace subsystem | |
256 | * @ops: pernet operations structure to manipulate | |
257 | * | |
258 | * Remove the pernet operations structure from the list to be | |
259 | * used when network namespaces are created or destoryed. In | |
260 | * addition run the exit method for all existing network | |
261 | * namespaces. | |
262 | */ | |
263 | void unregister_pernet_subsys(struct pernet_operations *module) | |
264 | { | |
265 | mutex_lock(&net_mutex); | |
266 | unregister_pernet_operations(module); | |
267 | mutex_unlock(&net_mutex); | |
268 | } | |
269 | EXPORT_SYMBOL_GPL(unregister_pernet_subsys); | |
270 | ||
271 | /** | |
272 | * register_pernet_device - register a network namespace device | |
273 | * @ops: pernet operations structure for the subsystem | |
274 | * | |
275 | * Register a device which has init and exit functions | |
276 | * that are called when network namespaces are created and | |
277 | * destroyed respectively. | |
278 | * | |
279 | * When registered all network namespace init functions are | |
280 | * called for every existing network namespace. Allowing kernel | |
281 | * modules to have a race free view of the set of network namespaces. | |
282 | * | |
283 | * When a new network namespace is created all of the init | |
284 | * methods are called in the order in which they were registered. | |
285 | * | |
286 | * When a network namespace is destroyed all of the exit methods | |
287 | * are called in the reverse of the order with which they were | |
288 | * registered. | |
289 | */ | |
290 | int register_pernet_device(struct pernet_operations *ops) | |
291 | { | |
292 | int error; | |
293 | mutex_lock(&net_mutex); | |
294 | error = register_pernet_operations(&pernet_list, ops); | |
295 | if (!error && (first_device == &pernet_list)) | |
296 | first_device = &ops->list; | |
297 | mutex_unlock(&net_mutex); | |
298 | return error; | |
299 | } | |
300 | EXPORT_SYMBOL_GPL(register_pernet_device); | |
301 | ||
302 | /** | |
303 | * unregister_pernet_device - unregister a network namespace netdevice | |
304 | * @ops: pernet operations structure to manipulate | |
305 | * | |
306 | * Remove the pernet operations structure from the list to be | |
307 | * used when network namespaces are created or destoryed. In | |
308 | * addition run the exit method for all existing network | |
309 | * namespaces. | |
310 | */ | |
311 | void unregister_pernet_device(struct pernet_operations *ops) | |
312 | { | |
313 | mutex_lock(&net_mutex); | |
314 | if (&ops->list == first_device) | |
315 | first_device = first_device->next; | |
316 | unregister_pernet_operations(ops); | |
317 | mutex_unlock(&net_mutex); | |
318 | } | |
319 | EXPORT_SYMBOL_GPL(unregister_pernet_device); |