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 <linux/netdevice.h>
12 #include <net/net_namespace.h>
13 #include <net/netns/generic.h>
14 #include <net/rtnetlink.h>
17 * Our network namespace constructor/destructor lists
20 static LIST_HEAD(pernet_list);
21 static struct list_head *first_device = &pernet_list;
22 static DEFINE_MUTEX(net_mutex);
24 LIST_HEAD(net_namespace_list);
25 EXPORT_SYMBOL_GPL(net_namespace_list);
28 EXPORT_SYMBOL(init_net);
30 #define INITIAL_NET_GEN_PTRS 13 /* +1 for len +2 for rcu_head */
32 static void unregister_netdevices(struct net *net, struct list_head *list)
34 struct net_device *dev;
35 /* At exit all network devices most be removed from a network
36 * namespace. Do this in the reverse order of registeration.
38 for_each_netdev_reverse(net, dev) {
39 if (dev->rtnl_link_ops)
40 dev->rtnl_link_ops->dellink(dev, list);
42 unregister_netdevice_queue(dev, list);
46 static int ops_init(const struct pernet_operations *ops, struct net *net)
49 if (ops->id && ops->size) {
50 void *data = kzalloc(ops->size, GFP_KERNEL);
54 err = net_assign_generic(net, *ops->id, data);
61 return ops->init(net);
65 static void ops_free(const struct pernet_operations *ops, struct net *net)
67 if (ops->id && ops->size) {
69 kfree(net_generic(net, id));
73 static void ops_exit_list(const struct pernet_operations *ops,
74 struct list_head *net_exit_list)
78 list_for_each_entry(net, net_exit_list, exit_list)
81 if (&ops->list == first_device) {
82 LIST_HEAD(dev_kill_list);
84 list_for_each_entry(net, net_exit_list, exit_list)
85 unregister_netdevices(net, &dev_kill_list);
86 unregister_netdevice_many(&dev_kill_list);
90 ops->exit_batch(net_exit_list);
93 static void ops_free_list(const struct pernet_operations *ops,
94 struct list_head *net_exit_list)
97 if (ops->size && ops->id) {
98 list_for_each_entry(net, net_exit_list, exit_list)
104 * setup_net runs the initializers for the network namespace object.
106 static __net_init int setup_net(struct net *net)
108 /* Must be called with net_mutex held */
109 const struct pernet_operations *ops, *saved_ops;
111 LIST_HEAD(net_exit_list);
113 atomic_set(&net->count, 1);
115 #ifdef NETNS_REFCNT_DEBUG
116 atomic_set(&net->use_count, 0);
119 list_for_each_entry(ops, &pernet_list, list) {
120 error = ops_init(ops, net);
128 /* Walk through the list backwards calling the exit functions
129 * for the pernet modules whose init functions did not fail.
131 list_add(&net->exit_list, &net_exit_list);
133 list_for_each_entry_continue_reverse(ops, &pernet_list, list)
134 ops_exit_list(ops, &net_exit_list);
137 list_for_each_entry_continue_reverse(ops, &pernet_list, list)
138 ops_free_list(ops, &net_exit_list);
144 static struct net_generic *net_alloc_generic(void)
146 struct net_generic *ng;
147 size_t generic_size = sizeof(struct net_generic) +
148 INITIAL_NET_GEN_PTRS * sizeof(void *);
150 ng = kzalloc(generic_size, GFP_KERNEL);
152 ng->len = INITIAL_NET_GEN_PTRS;
158 static struct kmem_cache *net_cachep;
159 static struct workqueue_struct *netns_wq;
161 static struct net *net_alloc(void)
163 struct net *net = NULL;
164 struct net_generic *ng;
166 ng = net_alloc_generic();
170 net = kmem_cache_zalloc(net_cachep, GFP_KERNEL);
174 rcu_assign_pointer(net->gen, ng);
183 static void net_free(struct net *net)
185 #ifdef NETNS_REFCNT_DEBUG
186 if (unlikely(atomic_read(&net->use_count) != 0)) {
187 printk(KERN_EMERG "network namespace not free! Usage: %d\n",
188 atomic_read(&net->use_count));
193 kmem_cache_free(net_cachep, net);
196 static struct net *net_create(void)
203 return ERR_PTR(-ENOMEM);
204 mutex_lock(&net_mutex);
208 list_add_tail_rcu(&net->list, &net_namespace_list);
211 mutex_unlock(&net_mutex);
219 struct net *copy_net_ns(unsigned long flags, struct net *old_net)
221 if (!(flags & CLONE_NEWNET))
222 return get_net(old_net);
226 static DEFINE_SPINLOCK(cleanup_list_lock);
227 static LIST_HEAD(cleanup_list); /* Must hold cleanup_list_lock to touch */
229 static void cleanup_net(struct work_struct *work)
231 const struct pernet_operations *ops;
232 struct net *net, *tmp;
233 LIST_HEAD(net_kill_list);
234 LIST_HEAD(net_exit_list);
236 /* Atomically snapshot the list of namespaces to cleanup */
237 spin_lock_irq(&cleanup_list_lock);
238 list_replace_init(&cleanup_list, &net_kill_list);
239 spin_unlock_irq(&cleanup_list_lock);
241 mutex_lock(&net_mutex);
243 /* Don't let anyone else find us. */
245 list_for_each_entry(net, &net_kill_list, cleanup_list) {
246 list_del_rcu(&net->list);
247 list_add_tail(&net->exit_list, &net_exit_list);
252 * Another CPU might be rcu-iterating the list, wait for it.
253 * This needs to be before calling the exit() notifiers, so
254 * the rcu_barrier() below isn't sufficient alone.
258 /* Run all of the network namespace exit methods */
259 list_for_each_entry_reverse(ops, &pernet_list, list)
260 ops_exit_list(ops, &net_exit_list);
262 /* Free the net generic variables */
263 list_for_each_entry_reverse(ops, &pernet_list, list)
264 ops_free_list(ops, &net_exit_list);
266 mutex_unlock(&net_mutex);
268 /* Ensure there are no outstanding rcu callbacks using this
273 /* Finally it is safe to free my network namespace structure */
274 list_for_each_entry_safe(net, tmp, &net_exit_list, exit_list) {
275 list_del_init(&net->exit_list);
279 static DECLARE_WORK(net_cleanup_work, cleanup_net);
281 void __put_net(struct net *net)
283 /* Cleanup the network namespace in process context */
286 spin_lock_irqsave(&cleanup_list_lock, flags);
287 list_add(&net->cleanup_list, &cleanup_list);
288 spin_unlock_irqrestore(&cleanup_list_lock, flags);
290 queue_work(netns_wq, &net_cleanup_work);
292 EXPORT_SYMBOL_GPL(__put_net);
295 struct net *copy_net_ns(unsigned long flags, struct net *old_net)
297 if (flags & CLONE_NEWNET)
298 return ERR_PTR(-EINVAL);
303 struct net *get_net_ns_by_pid(pid_t pid)
305 struct task_struct *tsk;
308 /* Lookup the network namespace */
309 net = ERR_PTR(-ESRCH);
311 tsk = find_task_by_vpid(pid);
313 struct nsproxy *nsproxy;
314 nsproxy = task_nsproxy(tsk);
316 net = get_net(nsproxy->net_ns);
321 EXPORT_SYMBOL_GPL(get_net_ns_by_pid);
323 static int __init net_ns_init(void)
325 struct net_generic *ng;
328 net_cachep = kmem_cache_create("net_namespace", sizeof(struct net),
332 /* Create workqueue for cleanup */
333 netns_wq = create_singlethread_workqueue("netns");
335 panic("Could not create netns workq");
338 ng = net_alloc_generic();
340 panic("Could not allocate generic netns");
342 rcu_assign_pointer(init_net.gen, ng);
344 mutex_lock(&net_mutex);
345 if (setup_net(&init_net))
346 panic("Could not setup the initial network namespace");
349 list_add_tail_rcu(&init_net.list, &net_namespace_list);
352 mutex_unlock(&net_mutex);
357 pure_initcall(net_ns_init);
360 static int __register_pernet_operations(struct list_head *list,
361 struct pernet_operations *ops)
365 LIST_HEAD(net_exit_list);
367 list_add_tail(&ops->list, list);
368 if (ops->init || (ops->id && ops->size)) {
370 error = ops_init(ops, net);
373 list_add_tail(&net->exit_list, &net_exit_list);
379 /* If I have an error cleanup all namespaces I initialized */
380 list_del(&ops->list);
381 ops_exit_list(ops, &net_exit_list);
382 ops_free_list(ops, &net_exit_list);
386 static void __unregister_pernet_operations(struct pernet_operations *ops)
389 LIST_HEAD(net_exit_list);
391 list_del(&ops->list);
393 list_add_tail(&net->exit_list, &net_exit_list);
394 ops_exit_list(ops, &net_exit_list);
395 ops_free_list(ops, &net_exit_list);
400 static int __register_pernet_operations(struct list_head *list,
401 struct pernet_operations *ops)
404 err = ops_init(ops, &init_net);
406 ops_free(ops, &init_net);
411 static void __unregister_pernet_operations(struct pernet_operations *ops)
413 LIST_HEAD(net_exit_list);
414 list_add(&init_net.exit_list, &net_exit_list);
415 ops_exit_list(ops, &net_exit_list);
416 ops_free_list(ops, &net_exit_list);
419 #endif /* CONFIG_NET_NS */
421 static DEFINE_IDA(net_generic_ids);
423 static int register_pernet_operations(struct list_head *list,
424 struct pernet_operations *ops)
430 error = ida_get_new_above(&net_generic_ids, 1, ops->id);
432 if (error == -EAGAIN) {
433 ida_pre_get(&net_generic_ids, GFP_KERNEL);
439 error = __register_pernet_operations(list, ops);
440 if (error && ops->id)
441 ida_remove(&net_generic_ids, *ops->id);
446 static void unregister_pernet_operations(struct pernet_operations *ops)
449 __unregister_pernet_operations(ops);
451 ida_remove(&net_generic_ids, *ops->id);
455 * register_pernet_subsys - register a network namespace subsystem
456 * @ops: pernet operations structure for the subsystem
458 * Register a subsystem which has init and exit functions
459 * that are called when network namespaces are created and
460 * destroyed respectively.
462 * When registered all network namespace init functions are
463 * called for every existing network namespace. Allowing kernel
464 * modules to have a race free view of the set of network namespaces.
466 * When a new network namespace is created all of the init
467 * methods are called in the order in which they were registered.
469 * When a network namespace is destroyed all of the exit methods
470 * are called in the reverse of the order with which they were
473 int register_pernet_subsys(struct pernet_operations *ops)
476 mutex_lock(&net_mutex);
477 error = register_pernet_operations(first_device, ops);
478 mutex_unlock(&net_mutex);
481 EXPORT_SYMBOL_GPL(register_pernet_subsys);
484 * unregister_pernet_subsys - unregister a network namespace subsystem
485 * @ops: pernet operations structure to manipulate
487 * Remove the pernet operations structure from the list to be
488 * used when network namespaces are created or destroyed. In
489 * addition run the exit method for all existing network
492 void unregister_pernet_subsys(struct pernet_operations *module)
494 mutex_lock(&net_mutex);
495 unregister_pernet_operations(module);
496 mutex_unlock(&net_mutex);
498 EXPORT_SYMBOL_GPL(unregister_pernet_subsys);
501 * register_pernet_device - register a network namespace device
502 * @ops: pernet operations structure for the subsystem
504 * Register a device which has init and exit functions
505 * that are called when network namespaces are created and
506 * destroyed respectively.
508 * When registered all network namespace init functions are
509 * called for every existing network namespace. Allowing kernel
510 * modules to have a race free view of the set of network namespaces.
512 * When a new network namespace is created all of the init
513 * methods are called in the order in which they were registered.
515 * When a network namespace is destroyed all of the exit methods
516 * are called in the reverse of the order with which they were
519 int register_pernet_device(struct pernet_operations *ops)
522 mutex_lock(&net_mutex);
523 error = register_pernet_operations(&pernet_list, ops);
524 if (!error && (first_device == &pernet_list))
525 first_device = &ops->list;
526 mutex_unlock(&net_mutex);
529 EXPORT_SYMBOL_GPL(register_pernet_device);
532 * unregister_pernet_device - unregister a network namespace netdevice
533 * @ops: pernet operations structure to manipulate
535 * Remove the pernet operations structure from the list to be
536 * used when network namespaces are created or destroyed. In
537 * addition run the exit method for all existing network
540 void unregister_pernet_device(struct pernet_operations *ops)
542 mutex_lock(&net_mutex);
543 if (&ops->list == first_device)
544 first_device = first_device->next;
545 unregister_pernet_operations(ops);
546 mutex_unlock(&net_mutex);
548 EXPORT_SYMBOL_GPL(unregister_pernet_device);
550 static void net_generic_release(struct rcu_head *rcu)
552 struct net_generic *ng;
554 ng = container_of(rcu, struct net_generic, rcu);
558 int net_assign_generic(struct net *net, int id, void *data)
560 struct net_generic *ng, *old_ng;
562 BUG_ON(!mutex_is_locked(&net_mutex));
565 ng = old_ng = net->gen;
566 if (old_ng->len >= id)
569 ng = kzalloc(sizeof(struct net_generic) +
570 id * sizeof(void *), GFP_KERNEL);
575 * Some synchronisation notes:
577 * The net_generic explores the net->gen array inside rcu
578 * read section. Besides once set the net->gen->ptr[x]
579 * pointer never changes (see rules in netns/generic.h).
581 * That said, we simply duplicate this array and schedule
582 * the old copy for kfree after a grace period.
586 memcpy(&ng->ptr, &old_ng->ptr, old_ng->len * sizeof(void*));
588 rcu_assign_pointer(net->gen, ng);
589 call_rcu(&old_ng->rcu, net_generic_release);
591 ng->ptr[id - 1] = data;
594 EXPORT_SYMBOL_GPL(net_assign_generic);