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git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - net/core/net_namespace.c
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>
9 #include <linux/rculist.h>
10 #include <linux/nsproxy.h>
11 #include <net/net_namespace.h>
12 #include <net/netns/generic.h>
15 * Our network namespace constructor/destructor lists
18 static LIST_HEAD(pernet_list
);
19 static struct list_head
*first_device
= &pernet_list
;
20 static DEFINE_MUTEX(net_mutex
);
22 LIST_HEAD(net_namespace_list
);
23 EXPORT_SYMBOL_GPL(net_namespace_list
);
26 EXPORT_SYMBOL(init_net
);
28 #define INITIAL_NET_GEN_PTRS 13 /* +1 for len +2 for rcu_head */
30 static void net_generic_release(struct rcu_head
*rcu
)
32 struct net_generic
*ng
;
34 ng
= container_of(rcu
, struct net_generic
, rcu
);
38 static int net_assign_generic(struct net
*net
, int id
, void *data
)
40 struct net_generic
*ng
, *old_ng
;
42 BUG_ON(!mutex_is_locked(&net_mutex
));
45 old_ng
= rcu_dereference_protected(net
->gen
,
46 lockdep_is_held(&net_mutex
));
48 if (old_ng
->len
>= id
)
51 ng
= kzalloc(sizeof(struct net_generic
) +
52 id
* sizeof(void *), GFP_KERNEL
);
57 * Some synchronisation notes:
59 * The net_generic explores the net->gen array inside rcu
60 * read section. Besides once set the net->gen->ptr[x]
61 * pointer never changes (see rules in netns/generic.h).
63 * That said, we simply duplicate this array and schedule
64 * the old copy for kfree after a grace period.
68 memcpy(&ng
->ptr
, &old_ng
->ptr
, old_ng
->len
* sizeof(void*));
70 rcu_assign_pointer(net
->gen
, ng
);
71 call_rcu(&old_ng
->rcu
, net_generic_release
);
73 ng
->ptr
[id
- 1] = data
;
77 static int ops_init(const struct pernet_operations
*ops
, struct net
*net
)
80 if (ops
->id
&& ops
->size
) {
81 void *data
= kzalloc(ops
->size
, GFP_KERNEL
);
85 err
= net_assign_generic(net
, *ops
->id
, data
);
92 return ops
->init(net
);
96 static void ops_free(const struct pernet_operations
*ops
, struct net
*net
)
98 if (ops
->id
&& ops
->size
) {
100 kfree(net_generic(net
, id
));
104 static void ops_exit_list(const struct pernet_operations
*ops
,
105 struct list_head
*net_exit_list
)
109 list_for_each_entry(net
, net_exit_list
, exit_list
)
113 ops
->exit_batch(net_exit_list
);
116 static void ops_free_list(const struct pernet_operations
*ops
,
117 struct list_head
*net_exit_list
)
120 if (ops
->size
&& ops
->id
) {
121 list_for_each_entry(net
, net_exit_list
, exit_list
)
127 * setup_net runs the initializers for the network namespace object.
129 static __net_init
int setup_net(struct net
*net
)
131 /* Must be called with net_mutex held */
132 const struct pernet_operations
*ops
, *saved_ops
;
134 LIST_HEAD(net_exit_list
);
136 atomic_set(&net
->count
, 1);
138 #ifdef NETNS_REFCNT_DEBUG
139 atomic_set(&net
->use_count
, 0);
142 list_for_each_entry(ops
, &pernet_list
, list
) {
143 error
= ops_init(ops
, net
);
151 /* Walk through the list backwards calling the exit functions
152 * for the pernet modules whose init functions did not fail.
154 list_add(&net
->exit_list
, &net_exit_list
);
156 list_for_each_entry_continue_reverse(ops
, &pernet_list
, list
)
157 ops_exit_list(ops
, &net_exit_list
);
160 list_for_each_entry_continue_reverse(ops
, &pernet_list
, list
)
161 ops_free_list(ops
, &net_exit_list
);
167 static struct net_generic
*net_alloc_generic(void)
169 struct net_generic
*ng
;
170 size_t generic_size
= sizeof(struct net_generic
) +
171 INITIAL_NET_GEN_PTRS
* sizeof(void *);
173 ng
= kzalloc(generic_size
, GFP_KERNEL
);
175 ng
->len
= INITIAL_NET_GEN_PTRS
;
181 static struct kmem_cache
*net_cachep
;
182 static struct workqueue_struct
*netns_wq
;
184 static struct net
*net_alloc(void)
186 struct net
*net
= NULL
;
187 struct net_generic
*ng
;
189 ng
= net_alloc_generic();
193 net
= kmem_cache_zalloc(net_cachep
, GFP_KERNEL
);
197 rcu_assign_pointer(net
->gen
, ng
);
206 static void net_free(struct net
*net
)
208 #ifdef NETNS_REFCNT_DEBUG
209 if (unlikely(atomic_read(&net
->use_count
) != 0)) {
210 printk(KERN_EMERG
"network namespace not free! Usage: %d\n",
211 atomic_read(&net
->use_count
));
216 kmem_cache_free(net_cachep
, net
);
219 struct net
*copy_net_ns(unsigned long flags
, struct net
*old_net
)
224 if (!(flags
& CLONE_NEWNET
))
225 return get_net(old_net
);
229 return ERR_PTR(-ENOMEM
);
230 mutex_lock(&net_mutex
);
234 list_add_tail_rcu(&net
->list
, &net_namespace_list
);
237 mutex_unlock(&net_mutex
);
245 static DEFINE_SPINLOCK(cleanup_list_lock
);
246 static LIST_HEAD(cleanup_list
); /* Must hold cleanup_list_lock to touch */
248 static void cleanup_net(struct work_struct
*work
)
250 const struct pernet_operations
*ops
;
251 struct net
*net
, *tmp
;
252 LIST_HEAD(net_kill_list
);
253 LIST_HEAD(net_exit_list
);
255 /* Atomically snapshot the list of namespaces to cleanup */
256 spin_lock_irq(&cleanup_list_lock
);
257 list_replace_init(&cleanup_list
, &net_kill_list
);
258 spin_unlock_irq(&cleanup_list_lock
);
260 mutex_lock(&net_mutex
);
262 /* Don't let anyone else find us. */
264 list_for_each_entry(net
, &net_kill_list
, cleanup_list
) {
265 list_del_rcu(&net
->list
);
266 list_add_tail(&net
->exit_list
, &net_exit_list
);
271 * Another CPU might be rcu-iterating the list, wait for it.
272 * This needs to be before calling the exit() notifiers, so
273 * the rcu_barrier() below isn't sufficient alone.
277 /* Run all of the network namespace exit methods */
278 list_for_each_entry_reverse(ops
, &pernet_list
, list
)
279 ops_exit_list(ops
, &net_exit_list
);
281 /* Free the net generic variables */
282 list_for_each_entry_reverse(ops
, &pernet_list
, list
)
283 ops_free_list(ops
, &net_exit_list
);
285 mutex_unlock(&net_mutex
);
287 /* Ensure there are no outstanding rcu callbacks using this
292 /* Finally it is safe to free my network namespace structure */
293 list_for_each_entry_safe(net
, tmp
, &net_exit_list
, exit_list
) {
294 list_del_init(&net
->exit_list
);
298 static DECLARE_WORK(net_cleanup_work
, cleanup_net
);
300 void __put_net(struct net
*net
)
302 /* Cleanup the network namespace in process context */
305 spin_lock_irqsave(&cleanup_list_lock
, flags
);
306 list_add(&net
->cleanup_list
, &cleanup_list
);
307 spin_unlock_irqrestore(&cleanup_list_lock
, flags
);
309 queue_work(netns_wq
, &net_cleanup_work
);
311 EXPORT_SYMBOL_GPL(__put_net
);
314 struct net
*copy_net_ns(unsigned long flags
, struct net
*old_net
)
316 if (flags
& CLONE_NEWNET
)
317 return ERR_PTR(-EINVAL
);
322 struct net
*get_net_ns_by_pid(pid_t pid
)
324 struct task_struct
*tsk
;
327 /* Lookup the network namespace */
328 net
= ERR_PTR(-ESRCH
);
330 tsk
= find_task_by_vpid(pid
);
332 struct nsproxy
*nsproxy
;
333 nsproxy
= task_nsproxy(tsk
);
335 net
= get_net(nsproxy
->net_ns
);
340 EXPORT_SYMBOL_GPL(get_net_ns_by_pid
);
342 static int __init
net_ns_init(void)
344 struct net_generic
*ng
;
347 net_cachep
= kmem_cache_create("net_namespace", sizeof(struct net
),
351 /* Create workqueue for cleanup */
352 netns_wq
= create_singlethread_workqueue("netns");
354 panic("Could not create netns workq");
357 ng
= net_alloc_generic();
359 panic("Could not allocate generic netns");
361 rcu_assign_pointer(init_net
.gen
, ng
);
363 mutex_lock(&net_mutex
);
364 if (setup_net(&init_net
))
365 panic("Could not setup the initial network namespace");
368 list_add_tail_rcu(&init_net
.list
, &net_namespace_list
);
371 mutex_unlock(&net_mutex
);
376 pure_initcall(net_ns_init
);
379 static int __register_pernet_operations(struct list_head
*list
,
380 struct pernet_operations
*ops
)
384 LIST_HEAD(net_exit_list
);
386 list_add_tail(&ops
->list
, list
);
387 if (ops
->init
|| (ops
->id
&& ops
->size
)) {
389 error
= ops_init(ops
, net
);
392 list_add_tail(&net
->exit_list
, &net_exit_list
);
398 /* If I have an error cleanup all namespaces I initialized */
399 list_del(&ops
->list
);
400 ops_exit_list(ops
, &net_exit_list
);
401 ops_free_list(ops
, &net_exit_list
);
405 static void __unregister_pernet_operations(struct pernet_operations
*ops
)
408 LIST_HEAD(net_exit_list
);
410 list_del(&ops
->list
);
412 list_add_tail(&net
->exit_list
, &net_exit_list
);
413 ops_exit_list(ops
, &net_exit_list
);
414 ops_free_list(ops
, &net_exit_list
);
419 static int __register_pernet_operations(struct list_head
*list
,
420 struct pernet_operations
*ops
)
423 err
= ops_init(ops
, &init_net
);
425 ops_free(ops
, &init_net
);
430 static void __unregister_pernet_operations(struct pernet_operations
*ops
)
432 LIST_HEAD(net_exit_list
);
433 list_add(&init_net
.exit_list
, &net_exit_list
);
434 ops_exit_list(ops
, &net_exit_list
);
435 ops_free_list(ops
, &net_exit_list
);
438 #endif /* CONFIG_NET_NS */
440 static DEFINE_IDA(net_generic_ids
);
442 static int register_pernet_operations(struct list_head
*list
,
443 struct pernet_operations
*ops
)
449 error
= ida_get_new_above(&net_generic_ids
, 1, ops
->id
);
451 if (error
== -EAGAIN
) {
452 ida_pre_get(&net_generic_ids
, GFP_KERNEL
);
458 error
= __register_pernet_operations(list
, ops
);
462 ida_remove(&net_generic_ids
, *ops
->id
);
468 static void unregister_pernet_operations(struct pernet_operations
*ops
)
471 __unregister_pernet_operations(ops
);
474 ida_remove(&net_generic_ids
, *ops
->id
);
478 * register_pernet_subsys - register a network namespace subsystem
479 * @ops: pernet operations structure for the subsystem
481 * Register a subsystem which has init and exit functions
482 * that are called when network namespaces are created and
483 * destroyed respectively.
485 * When registered all network namespace init functions are
486 * called for every existing network namespace. Allowing kernel
487 * modules to have a race free view of the set of network namespaces.
489 * When a new network namespace is created all of the init
490 * methods are called in the order in which they were registered.
492 * When a network namespace is destroyed all of the exit methods
493 * are called in the reverse of the order with which they were
496 int register_pernet_subsys(struct pernet_operations
*ops
)
499 mutex_lock(&net_mutex
);
500 error
= register_pernet_operations(first_device
, ops
);
501 mutex_unlock(&net_mutex
);
504 EXPORT_SYMBOL_GPL(register_pernet_subsys
);
507 * unregister_pernet_subsys - unregister a network namespace subsystem
508 * @ops: pernet operations structure to manipulate
510 * Remove the pernet operations structure from the list to be
511 * used when network namespaces are created or destroyed. In
512 * addition run the exit method for all existing network
515 void unregister_pernet_subsys(struct pernet_operations
*ops
)
517 mutex_lock(&net_mutex
);
518 unregister_pernet_operations(ops
);
519 mutex_unlock(&net_mutex
);
521 EXPORT_SYMBOL_GPL(unregister_pernet_subsys
);
524 * register_pernet_device - register a network namespace device
525 * @ops: pernet operations structure for the subsystem
527 * Register a device which has init and exit functions
528 * that are called when network namespaces are created and
529 * destroyed respectively.
531 * When registered all network namespace init functions are
532 * called for every existing network namespace. Allowing kernel
533 * modules to have a race free view of the set of network namespaces.
535 * When a new network namespace is created all of the init
536 * methods are called in the order in which they were registered.
538 * When a network namespace is destroyed all of the exit methods
539 * are called in the reverse of the order with which they were
542 int register_pernet_device(struct pernet_operations
*ops
)
545 mutex_lock(&net_mutex
);
546 error
= register_pernet_operations(&pernet_list
, ops
);
547 if (!error
&& (first_device
== &pernet_list
))
548 first_device
= &ops
->list
;
549 mutex_unlock(&net_mutex
);
552 EXPORT_SYMBOL_GPL(register_pernet_device
);
555 * unregister_pernet_device - unregister a network namespace netdevice
556 * @ops: pernet operations structure to manipulate
558 * Remove the pernet operations structure from the list to be
559 * used when network namespaces are created or destroyed. In
560 * addition run the exit method for all existing network
563 void unregister_pernet_device(struct pernet_operations
*ops
)
565 mutex_lock(&net_mutex
);
566 if (&ops
->list
== first_device
)
567 first_device
= first_device
->next
;
568 unregister_pernet_operations(ops
);
569 mutex_unlock(&net_mutex
);
571 EXPORT_SYMBOL_GPL(unregister_pernet_device
);