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 static struct net
*net_create(void)
226 return ERR_PTR(-ENOMEM
);
227 mutex_lock(&net_mutex
);
231 list_add_tail_rcu(&net
->list
, &net_namespace_list
);
234 mutex_unlock(&net_mutex
);
242 struct net
*copy_net_ns(unsigned long flags
, struct net
*old_net
)
244 if (!(flags
& CLONE_NEWNET
))
245 return get_net(old_net
);
249 static DEFINE_SPINLOCK(cleanup_list_lock
);
250 static LIST_HEAD(cleanup_list
); /* Must hold cleanup_list_lock to touch */
252 static void cleanup_net(struct work_struct
*work
)
254 const struct pernet_operations
*ops
;
255 struct net
*net
, *tmp
;
256 LIST_HEAD(net_kill_list
);
257 LIST_HEAD(net_exit_list
);
259 /* Atomically snapshot the list of namespaces to cleanup */
260 spin_lock_irq(&cleanup_list_lock
);
261 list_replace_init(&cleanup_list
, &net_kill_list
);
262 spin_unlock_irq(&cleanup_list_lock
);
264 mutex_lock(&net_mutex
);
266 /* Don't let anyone else find us. */
268 list_for_each_entry(net
, &net_kill_list
, cleanup_list
) {
269 list_del_rcu(&net
->list
);
270 list_add_tail(&net
->exit_list
, &net_exit_list
);
275 * Another CPU might be rcu-iterating the list, wait for it.
276 * This needs to be before calling the exit() notifiers, so
277 * the rcu_barrier() below isn't sufficient alone.
281 /* Run all of the network namespace exit methods */
282 list_for_each_entry_reverse(ops
, &pernet_list
, list
)
283 ops_exit_list(ops
, &net_exit_list
);
285 /* Free the net generic variables */
286 list_for_each_entry_reverse(ops
, &pernet_list
, list
)
287 ops_free_list(ops
, &net_exit_list
);
289 mutex_unlock(&net_mutex
);
291 /* Ensure there are no outstanding rcu callbacks using this
296 /* Finally it is safe to free my network namespace structure */
297 list_for_each_entry_safe(net
, tmp
, &net_exit_list
, exit_list
) {
298 list_del_init(&net
->exit_list
);
302 static DECLARE_WORK(net_cleanup_work
, cleanup_net
);
304 void __put_net(struct net
*net
)
306 /* Cleanup the network namespace in process context */
309 spin_lock_irqsave(&cleanup_list_lock
, flags
);
310 list_add(&net
->cleanup_list
, &cleanup_list
);
311 spin_unlock_irqrestore(&cleanup_list_lock
, flags
);
313 queue_work(netns_wq
, &net_cleanup_work
);
315 EXPORT_SYMBOL_GPL(__put_net
);
318 struct net
*copy_net_ns(unsigned long flags
, struct net
*old_net
)
320 if (flags
& CLONE_NEWNET
)
321 return ERR_PTR(-EINVAL
);
326 struct net
*get_net_ns_by_pid(pid_t pid
)
328 struct task_struct
*tsk
;
331 /* Lookup the network namespace */
332 net
= ERR_PTR(-ESRCH
);
334 tsk
= find_task_by_vpid(pid
);
336 struct nsproxy
*nsproxy
;
337 nsproxy
= task_nsproxy(tsk
);
339 net
= get_net(nsproxy
->net_ns
);
344 EXPORT_SYMBOL_GPL(get_net_ns_by_pid
);
346 static int __init
net_ns_init(void)
348 struct net_generic
*ng
;
351 net_cachep
= kmem_cache_create("net_namespace", sizeof(struct net
),
355 /* Create workqueue for cleanup */
356 netns_wq
= create_singlethread_workqueue("netns");
358 panic("Could not create netns workq");
361 ng
= net_alloc_generic();
363 panic("Could not allocate generic netns");
365 rcu_assign_pointer(init_net
.gen
, ng
);
367 mutex_lock(&net_mutex
);
368 if (setup_net(&init_net
))
369 panic("Could not setup the initial network namespace");
372 list_add_tail_rcu(&init_net
.list
, &net_namespace_list
);
375 mutex_unlock(&net_mutex
);
380 pure_initcall(net_ns_init
);
383 static int __register_pernet_operations(struct list_head
*list
,
384 struct pernet_operations
*ops
)
388 LIST_HEAD(net_exit_list
);
390 list_add_tail(&ops
->list
, list
);
391 if (ops
->init
|| (ops
->id
&& ops
->size
)) {
393 error
= ops_init(ops
, net
);
396 list_add_tail(&net
->exit_list
, &net_exit_list
);
402 /* If I have an error cleanup all namespaces I initialized */
403 list_del(&ops
->list
);
404 ops_exit_list(ops
, &net_exit_list
);
405 ops_free_list(ops
, &net_exit_list
);
409 static void __unregister_pernet_operations(struct pernet_operations
*ops
)
412 LIST_HEAD(net_exit_list
);
414 list_del(&ops
->list
);
416 list_add_tail(&net
->exit_list
, &net_exit_list
);
417 ops_exit_list(ops
, &net_exit_list
);
418 ops_free_list(ops
, &net_exit_list
);
423 static int __register_pernet_operations(struct list_head
*list
,
424 struct pernet_operations
*ops
)
427 err
= ops_init(ops
, &init_net
);
429 ops_free(ops
, &init_net
);
434 static void __unregister_pernet_operations(struct pernet_operations
*ops
)
436 LIST_HEAD(net_exit_list
);
437 list_add(&init_net
.exit_list
, &net_exit_list
);
438 ops_exit_list(ops
, &net_exit_list
);
439 ops_free_list(ops
, &net_exit_list
);
442 #endif /* CONFIG_NET_NS */
444 static DEFINE_IDA(net_generic_ids
);
446 static int register_pernet_operations(struct list_head
*list
,
447 struct pernet_operations
*ops
)
453 error
= ida_get_new_above(&net_generic_ids
, 1, ops
->id
);
455 if (error
== -EAGAIN
) {
456 ida_pre_get(&net_generic_ids
, GFP_KERNEL
);
462 error
= __register_pernet_operations(list
, ops
);
466 ida_remove(&net_generic_ids
, *ops
->id
);
472 static void unregister_pernet_operations(struct pernet_operations
*ops
)
475 __unregister_pernet_operations(ops
);
478 ida_remove(&net_generic_ids
, *ops
->id
);
482 * register_pernet_subsys - register a network namespace subsystem
483 * @ops: pernet operations structure for the subsystem
485 * Register a subsystem which has init and exit functions
486 * that are called when network namespaces are created and
487 * destroyed respectively.
489 * When registered all network namespace init functions are
490 * called for every existing network namespace. Allowing kernel
491 * modules to have a race free view of the set of network namespaces.
493 * When a new network namespace is created all of the init
494 * methods are called in the order in which they were registered.
496 * When a network namespace is destroyed all of the exit methods
497 * are called in the reverse of the order with which they were
500 int register_pernet_subsys(struct pernet_operations
*ops
)
503 mutex_lock(&net_mutex
);
504 error
= register_pernet_operations(first_device
, ops
);
505 mutex_unlock(&net_mutex
);
508 EXPORT_SYMBOL_GPL(register_pernet_subsys
);
511 * unregister_pernet_subsys - unregister a network namespace subsystem
512 * @ops: pernet operations structure to manipulate
514 * Remove the pernet operations structure from the list to be
515 * used when network namespaces are created or destroyed. In
516 * addition run the exit method for all existing network
519 void unregister_pernet_subsys(struct pernet_operations
*ops
)
521 mutex_lock(&net_mutex
);
522 unregister_pernet_operations(ops
);
523 mutex_unlock(&net_mutex
);
525 EXPORT_SYMBOL_GPL(unregister_pernet_subsys
);
528 * register_pernet_device - register a network namespace device
529 * @ops: pernet operations structure for the subsystem
531 * Register a device which has init and exit functions
532 * that are called when network namespaces are created and
533 * destroyed respectively.
535 * When registered all network namespace init functions are
536 * called for every existing network namespace. Allowing kernel
537 * modules to have a race free view of the set of network namespaces.
539 * When a new network namespace is created all of the init
540 * methods are called in the order in which they were registered.
542 * When a network namespace is destroyed all of the exit methods
543 * are called in the reverse of the order with which they were
546 int register_pernet_device(struct pernet_operations
*ops
)
549 mutex_lock(&net_mutex
);
550 error
= register_pernet_operations(&pernet_list
, ops
);
551 if (!error
&& (first_device
== &pernet_list
))
552 first_device
= &ops
->list
;
553 mutex_unlock(&net_mutex
);
556 EXPORT_SYMBOL_GPL(register_pernet_device
);
559 * unregister_pernet_device - unregister a network namespace netdevice
560 * @ops: pernet operations structure to manipulate
562 * Remove the pernet operations structure from the list to be
563 * used when network namespaces are created or destroyed. In
564 * addition run the exit method for all existing network
567 void unregister_pernet_device(struct pernet_operations
*ops
)
569 mutex_lock(&net_mutex
);
570 if (&ops
->list
== first_device
)
571 first_device
= first_device
->next
;
572 unregister_pernet_operations(ops
);
573 mutex_unlock(&net_mutex
);
575 EXPORT_SYMBOL_GPL(unregister_pernet_device
);
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