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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> | |
7 | #include <linux/sched.h> | |
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 | ||
18 | LIST_HEAD(net_namespace_list); | |
19 | ||
20 | struct net init_net; | |
21 | EXPORT_SYMBOL_GPL(init_net); | |
22 | ||
23 | /* | |
24 | * setup_net runs the initializers for the network namespace object. | |
25 | */ | |
26 | static __net_init int setup_net(struct net *net) | |
27 | { | |
28 | /* Must be called with net_mutex held */ | |
29 | struct pernet_operations *ops; | |
30 | int error; | |
31 | ||
32 | atomic_set(&net->count, 1); | |
33 | atomic_set(&net->use_count, 0); | |
34 | ||
35 | error = 0; | |
36 | list_for_each_entry(ops, &pernet_list, list) { | |
37 | if (ops->init) { | |
38 | error = ops->init(net); | |
39 | if (error < 0) | |
40 | goto out_undo; | |
41 | } | |
42 | } | |
43 | out: | |
44 | return error; | |
45 | ||
46 | out_undo: | |
47 | /* Walk through the list backwards calling the exit functions | |
48 | * for the pernet modules whose init functions did not fail. | |
49 | */ | |
50 | list_for_each_entry_continue_reverse(ops, &pernet_list, list) { | |
51 | if (ops->exit) | |
52 | ops->exit(net); | |
53 | } | |
54 | ||
55 | rcu_barrier(); | |
56 | goto out; | |
57 | } | |
58 | ||
59 | #ifdef CONFIG_NET_NS | |
60 | static struct kmem_cache *net_cachep; | |
61 | ||
62 | static struct net *net_alloc(void) | |
63 | { | |
64 | return kmem_cache_zalloc(net_cachep, GFP_KERNEL); | |
65 | } | |
66 | ||
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 | ||
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 | ||
87 | rtnl_lock(); | |
88 | list_add_tail(&new_net->list, &net_namespace_list); | |
89 | rtnl_unlock(); | |
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 | ||
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 | ||
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 | #ifdef CONFIG_NET_NS | |
171 | net_cachep = kmem_cache_create("net_namespace", sizeof(struct net), | |
172 | SMP_CACHE_BYTES, | |
173 | SLAB_PANIC, NULL); | |
174 | #endif | |
175 | mutex_lock(&net_mutex); | |
176 | err = setup_net(&init_net); | |
177 | ||
178 | rtnl_lock(); | |
179 | list_add_tail(&init_net.list, &net_namespace_list); | |
180 | rtnl_unlock(); | |
181 | ||
182 | mutex_unlock(&net_mutex); | |
183 | if (err) | |
184 | panic("Could not setup the initial network namespace"); | |
185 | ||
186 | return 0; | |
187 | } | |
188 | ||
189 | pure_initcall(net_ns_init); | |
190 | ||
191 | static int register_pernet_operations(struct list_head *list, | |
192 | struct pernet_operations *ops) | |
193 | { | |
194 | struct net *net, *undo_net; | |
195 | int error; | |
196 | ||
197 | list_add_tail(&ops->list, list); | |
198 | if (ops->init) { | |
199 | for_each_net(net) { | |
200 | error = ops->init(net); | |
201 | if (error) | |
202 | goto out_undo; | |
203 | } | |
204 | } | |
205 | return 0; | |
206 | ||
207 | out_undo: | |
208 | /* If I have an error cleanup all namespaces I initialized */ | |
209 | list_del(&ops->list); | |
210 | if (ops->exit) { | |
211 | for_each_net(undo_net) { | |
212 | if (undo_net == net) | |
213 | goto undone; | |
214 | ops->exit(undo_net); | |
215 | } | |
216 | } | |
217 | undone: | |
218 | return error; | |
219 | } | |
220 | ||
221 | static void unregister_pernet_operations(struct pernet_operations *ops) | |
222 | { | |
223 | struct net *net; | |
224 | ||
225 | list_del(&ops->list); | |
226 | if (ops->exit) | |
227 | for_each_net(net) | |
228 | ops->exit(net); | |
229 | } | |
230 | ||
231 | /** | |
232 | * register_pernet_subsys - register a network namespace subsystem | |
233 | * @ops: pernet operations structure for the subsystem | |
234 | * | |
235 | * Register a subsystem which has init and exit functions | |
236 | * that are called when network namespaces are created and | |
237 | * destroyed respectively. | |
238 | * | |
239 | * When registered all network namespace init functions are | |
240 | * called for every existing network namespace. Allowing kernel | |
241 | * modules to have a race free view of the set of network namespaces. | |
242 | * | |
243 | * When a new network namespace is created all of the init | |
244 | * methods are called in the order in which they were registered. | |
245 | * | |
246 | * When a network namespace is destroyed all of the exit methods | |
247 | * are called in the reverse of the order with which they were | |
248 | * registered. | |
249 | */ | |
250 | int register_pernet_subsys(struct pernet_operations *ops) | |
251 | { | |
252 | int error; | |
253 | mutex_lock(&net_mutex); | |
254 | error = register_pernet_operations(first_device, ops); | |
255 | mutex_unlock(&net_mutex); | |
256 | return error; | |
257 | } | |
258 | EXPORT_SYMBOL_GPL(register_pernet_subsys); | |
259 | ||
260 | /** | |
261 | * unregister_pernet_subsys - unregister a network namespace subsystem | |
262 | * @ops: pernet operations structure to manipulate | |
263 | * | |
264 | * Remove the pernet operations structure from the list to be | |
265 | * used when network namespaces are created or destoryed. In | |
266 | * addition run the exit method for all existing network | |
267 | * namespaces. | |
268 | */ | |
269 | void unregister_pernet_subsys(struct pernet_operations *module) | |
270 | { | |
271 | mutex_lock(&net_mutex); | |
272 | unregister_pernet_operations(module); | |
273 | mutex_unlock(&net_mutex); | |
274 | } | |
275 | EXPORT_SYMBOL_GPL(unregister_pernet_subsys); | |
276 | ||
277 | /** | |
278 | * register_pernet_device - register a network namespace device | |
279 | * @ops: pernet operations structure for the subsystem | |
280 | * | |
281 | * Register a device which has init and exit functions | |
282 | * that are called when network namespaces are created and | |
283 | * destroyed respectively. | |
284 | * | |
285 | * When registered all network namespace init functions are | |
286 | * called for every existing network namespace. Allowing kernel | |
287 | * modules to have a race free view of the set of network namespaces. | |
288 | * | |
289 | * When a new network namespace is created all of the init | |
290 | * methods are called in the order in which they were registered. | |
291 | * | |
292 | * When a network namespace is destroyed all of the exit methods | |
293 | * are called in the reverse of the order with which they were | |
294 | * registered. | |
295 | */ | |
296 | int register_pernet_device(struct pernet_operations *ops) | |
297 | { | |
298 | int error; | |
299 | mutex_lock(&net_mutex); | |
300 | error = register_pernet_operations(&pernet_list, ops); | |
301 | if (!error && (first_device == &pernet_list)) | |
302 | first_device = &ops->list; | |
303 | mutex_unlock(&net_mutex); | |
304 | return error; | |
305 | } | |
306 | EXPORT_SYMBOL_GPL(register_pernet_device); | |
307 | ||
308 | /** | |
309 | * unregister_pernet_device - unregister a network namespace netdevice | |
310 | * @ops: pernet operations structure to manipulate | |
311 | * | |
312 | * Remove the pernet operations structure from the list to be | |
313 | * used when network namespaces are created or destoryed. In | |
314 | * addition run the exit method for all existing network | |
315 | * namespaces. | |
316 | */ | |
317 | void unregister_pernet_device(struct pernet_operations *ops) | |
318 | { | |
319 | mutex_lock(&net_mutex); | |
320 | if (&ops->list == first_device) | |
321 | first_device = first_device->next; | |
322 | unregister_pernet_operations(ops); | |
323 | mutex_unlock(&net_mutex); | |
324 | } | |
325 | EXPORT_SYMBOL_GPL(unregister_pernet_device); |