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 <net/net_namespace.h>
10 #include <net/netns/generic.h>
13 * Our network namespace constructor/destructor lists
16 static LIST_HEAD(pernet_list);
17 static struct list_head *first_device = &pernet_list;
18 static DEFINE_MUTEX(net_mutex);
20 LIST_HEAD(net_namespace_list);
21 EXPORT_SYMBOL_GPL(net_namespace_list);
24 EXPORT_SYMBOL(init_net);
26 #define INITIAL_NET_GEN_PTRS 13 /* +1 for len +2 for rcu_head */
29 * setup_net runs the initializers for the network namespace object.
31 static __net_init int setup_net(struct net *net)
33 /* Must be called with net_mutex held */
34 struct pernet_operations *ops;
37 atomic_set(&net->count, 1);
39 #ifdef NETNS_REFCNT_DEBUG
40 atomic_set(&net->use_count, 0);
43 list_for_each_entry(ops, &pernet_list, list) {
45 error = ops->init(net);
54 /* Walk through the list backwards calling the exit functions
55 * for the pernet modules whose init functions did not fail.
57 list_for_each_entry_continue_reverse(ops, &pernet_list, list) {
66 static struct net_generic *net_alloc_generic(void)
68 struct net_generic *ng;
69 size_t generic_size = sizeof(struct net_generic) +
70 INITIAL_NET_GEN_PTRS * sizeof(void *);
72 ng = kzalloc(generic_size, GFP_KERNEL);
74 ng->len = INITIAL_NET_GEN_PTRS;
80 static struct kmem_cache *net_cachep;
81 static struct workqueue_struct *netns_wq;
83 static struct net *net_alloc(void)
85 struct net *net = NULL;
86 struct net_generic *ng;
88 ng = net_alloc_generic();
92 net = kmem_cache_zalloc(net_cachep, GFP_KERNEL);
96 rcu_assign_pointer(net->gen, ng);
105 static void net_free(struct net *net)
107 #ifdef NETNS_REFCNT_DEBUG
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));
115 kmem_cache_free(net_cachep, net);
118 static struct net *net_create(void)
125 return ERR_PTR(-ENOMEM);
126 mutex_lock(&net_mutex);
130 list_add_tail(&net->list, &net_namespace_list);
133 mutex_unlock(&net_mutex);
141 struct net *copy_net_ns(unsigned long flags, struct net *old_net)
143 if (!(flags & CLONE_NEWNET))
144 return get_net(old_net);
148 static void cleanup_net(struct work_struct *work)
150 struct pernet_operations *ops;
153 net = container_of(work, struct net, work);
155 mutex_lock(&net_mutex);
157 /* Don't let anyone else find us. */
159 list_del(&net->list);
162 /* Run all of the network namespace exit methods */
163 list_for_each_entry_reverse(ops, &pernet_list, list) {
168 mutex_unlock(&net_mutex);
170 /* Ensure there are no outstanding rcu callbacks using this
175 /* Finally it is safe to free my network namespace structure */
179 void __put_net(struct net *net)
181 /* Cleanup the network namespace in process context */
182 INIT_WORK(&net->work, cleanup_net);
183 queue_work(netns_wq, &net->work);
185 EXPORT_SYMBOL_GPL(__put_net);
188 struct net *copy_net_ns(unsigned long flags, struct net *old_net)
190 if (flags & CLONE_NEWNET)
191 return ERR_PTR(-EINVAL);
196 static int __init net_ns_init(void)
198 struct net_generic *ng;
201 printk(KERN_INFO "net_namespace: %zd bytes\n", sizeof(struct net));
203 net_cachep = kmem_cache_create("net_namespace", sizeof(struct net),
207 /* Create workqueue for cleanup */
208 netns_wq = create_singlethread_workqueue("netns");
210 panic("Could not create netns workq");
213 ng = net_alloc_generic();
215 panic("Could not allocate generic netns");
217 rcu_assign_pointer(init_net.gen, ng);
219 mutex_lock(&net_mutex);
220 err = setup_net(&init_net);
223 list_add_tail(&init_net.list, &net_namespace_list);
226 mutex_unlock(&net_mutex);
228 panic("Could not setup the initial network namespace");
233 pure_initcall(net_ns_init);
236 static int register_pernet_operations(struct list_head *list,
237 struct pernet_operations *ops)
239 struct net *net, *undo_net;
242 list_add_tail(&ops->list, list);
245 error = ops->init(net);
253 /* If I have an error cleanup all namespaces I initialized */
254 list_del(&ops->list);
256 for_each_net(undo_net) {
266 static void unregister_pernet_operations(struct pernet_operations *ops)
270 list_del(&ops->list);
278 static int register_pernet_operations(struct list_head *list,
279 struct pernet_operations *ops)
281 if (ops->init == NULL)
283 return ops->init(&init_net);
286 static void unregister_pernet_operations(struct pernet_operations *ops)
289 ops->exit(&init_net);
293 static DEFINE_IDA(net_generic_ids);
296 * register_pernet_subsys - register a network namespace subsystem
297 * @ops: pernet operations structure for the subsystem
299 * Register a subsystem which has init and exit functions
300 * that are called when network namespaces are created and
301 * destroyed respectively.
303 * When registered all network namespace init functions are
304 * called for every existing network namespace. Allowing kernel
305 * modules to have a race free view of the set of network namespaces.
307 * When a new network namespace is created all of the init
308 * methods are called in the order in which they were registered.
310 * When a network namespace is destroyed all of the exit methods
311 * are called in the reverse of the order with which they were
314 int register_pernet_subsys(struct pernet_operations *ops)
317 mutex_lock(&net_mutex);
318 error = register_pernet_operations(first_device, ops);
319 mutex_unlock(&net_mutex);
322 EXPORT_SYMBOL_GPL(register_pernet_subsys);
325 * unregister_pernet_subsys - unregister a network namespace subsystem
326 * @ops: pernet operations structure to manipulate
328 * Remove the pernet operations structure from the list to be
329 * used when network namespaces are created or destroyed. In
330 * addition run the exit method for all existing network
333 void unregister_pernet_subsys(struct pernet_operations *module)
335 mutex_lock(&net_mutex);
336 unregister_pernet_operations(module);
337 mutex_unlock(&net_mutex);
339 EXPORT_SYMBOL_GPL(unregister_pernet_subsys);
341 int register_pernet_gen_subsys(int *id, struct pernet_operations *ops)
345 mutex_lock(&net_mutex);
347 rv = ida_get_new_above(&net_generic_ids, 1, id);
350 ida_pre_get(&net_generic_ids, GFP_KERNEL);
355 rv = register_pernet_operations(first_device, ops);
357 ida_remove(&net_generic_ids, *id);
359 mutex_unlock(&net_mutex);
362 EXPORT_SYMBOL_GPL(register_pernet_gen_subsys);
364 void unregister_pernet_gen_subsys(int id, struct pernet_operations *ops)
366 mutex_lock(&net_mutex);
367 unregister_pernet_operations(ops);
368 ida_remove(&net_generic_ids, id);
369 mutex_unlock(&net_mutex);
371 EXPORT_SYMBOL_GPL(unregister_pernet_gen_subsys);
374 * register_pernet_device - register a network namespace device
375 * @ops: pernet operations structure for the subsystem
377 * Register a device which has init and exit functions
378 * that are called when network namespaces are created and
379 * destroyed respectively.
381 * When registered all network namespace init functions are
382 * called for every existing network namespace. Allowing kernel
383 * modules to have a race free view of the set of network namespaces.
385 * When a new network namespace is created all of the init
386 * methods are called in the order in which they were registered.
388 * When a network namespace is destroyed all of the exit methods
389 * are called in the reverse of the order with which they were
392 int register_pernet_device(struct pernet_operations *ops)
395 mutex_lock(&net_mutex);
396 error = register_pernet_operations(&pernet_list, ops);
397 if (!error && (first_device == &pernet_list))
398 first_device = &ops->list;
399 mutex_unlock(&net_mutex);
402 EXPORT_SYMBOL_GPL(register_pernet_device);
404 int register_pernet_gen_device(int *id, struct pernet_operations *ops)
407 mutex_lock(&net_mutex);
409 error = ida_get_new_above(&net_generic_ids, 1, id);
411 if (error == -EAGAIN) {
412 ida_pre_get(&net_generic_ids, GFP_KERNEL);
417 error = register_pernet_operations(&pernet_list, ops);
419 ida_remove(&net_generic_ids, *id);
420 else if (first_device == &pernet_list)
421 first_device = &ops->list;
423 mutex_unlock(&net_mutex);
426 EXPORT_SYMBOL_GPL(register_pernet_gen_device);
429 * unregister_pernet_device - unregister a network namespace netdevice
430 * @ops: pernet operations structure to manipulate
432 * Remove the pernet operations structure from the list to be
433 * used when network namespaces are created or destroyed. In
434 * addition run the exit method for all existing network
437 void unregister_pernet_device(struct pernet_operations *ops)
439 mutex_lock(&net_mutex);
440 if (&ops->list == first_device)
441 first_device = first_device->next;
442 unregister_pernet_operations(ops);
443 mutex_unlock(&net_mutex);
445 EXPORT_SYMBOL_GPL(unregister_pernet_device);
447 void unregister_pernet_gen_device(int id, struct pernet_operations *ops)
449 mutex_lock(&net_mutex);
450 if (&ops->list == first_device)
451 first_device = first_device->next;
452 unregister_pernet_operations(ops);
453 ida_remove(&net_generic_ids, id);
454 mutex_unlock(&net_mutex);
456 EXPORT_SYMBOL_GPL(unregister_pernet_gen_device);
458 static void net_generic_release(struct rcu_head *rcu)
460 struct net_generic *ng;
462 ng = container_of(rcu, struct net_generic, rcu);
466 int net_assign_generic(struct net *net, int id, void *data)
468 struct net_generic *ng, *old_ng;
470 BUG_ON(!mutex_is_locked(&net_mutex));
473 ng = old_ng = net->gen;
474 if (old_ng->len >= id)
477 ng = kzalloc(sizeof(struct net_generic) +
478 id * sizeof(void *), GFP_KERNEL);
483 * Some synchronisation notes:
485 * The net_generic explores the net->gen array inside rcu
486 * read section. Besides once set the net->gen->ptr[x]
487 * pointer never changes (see rules in netns/generic.h).
489 * That said, we simply duplicate this array and schedule
490 * the old copy for kfree after a grace period.
494 memcpy(&ng->ptr, &old_ng->ptr, old_ng->len);
496 rcu_assign_pointer(net->gen, ng);
497 call_rcu(&old_ng->rcu, net_generic_release);
499 ng->ptr[id - 1] = data;
502 EXPORT_SYMBOL_GPL(net_assign_generic);