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>
11 * Our network namespace constructor/destructor lists
14 static LIST_HEAD(pernet_list);
15 static struct list_head *first_device = &pernet_list;
16 static DEFINE_MUTEX(net_mutex);
18 LIST_HEAD(net_namespace_list);
20 static struct kmem_cache *net_cachep;
23 EXPORT_SYMBOL_GPL(init_net);
25 static struct net *net_alloc(void)
27 return kmem_cache_alloc(net_cachep, GFP_KERNEL);
30 static void net_free(struct net *net)
35 if (unlikely(atomic_read(&net->use_count) != 0)) {
36 printk(KERN_EMERG "network namespace not free! Usage: %d\n",
37 atomic_read(&net->use_count));
41 kmem_cache_free(net_cachep, net);
44 static void cleanup_net(struct work_struct *work)
46 struct pernet_operations *ops;
49 net = container_of(work, struct net, work);
51 mutex_lock(&net_mutex);
53 /* Don't let anyone else find us. */
58 /* Run all of the network namespace exit methods */
59 list_for_each_entry_reverse(ops, &pernet_list, list) {
64 mutex_unlock(&net_mutex);
66 /* Ensure there are no outstanding rcu callbacks using this
71 /* Finally it is safe to free my network namespace structure */
76 void __put_net(struct net *net)
78 /* Cleanup the network namespace in process context */
79 INIT_WORK(&net->work, cleanup_net);
80 schedule_work(&net->work);
82 EXPORT_SYMBOL_GPL(__put_net);
85 * setup_net runs the initializers for the network namespace object.
87 static int setup_net(struct net *net)
89 /* Must be called with net_mutex held */
90 struct pernet_operations *ops;
93 memset(net, 0, sizeof(struct net));
94 atomic_set(&net->count, 1);
95 atomic_set(&net->use_count, 0);
98 list_for_each_entry(ops, &pernet_list, list) {
100 error = ops->init(net);
109 /* Walk through the list backwards calling the exit functions
110 * for the pernet modules whose init functions did not fail.
112 list_for_each_entry_continue_reverse(ops, &pernet_list, list) {
119 struct net *copy_net_ns(unsigned long flags, struct net *old_net)
121 struct net *new_net = NULL;
126 if (!(flags & CLONE_NEWNET))
129 #ifndef CONFIG_NET_NS
130 return ERR_PTR(-EINVAL);
134 new_net = net_alloc();
138 mutex_lock(&net_mutex);
139 err = setup_net(new_net);
144 list_add_tail(&new_net->list, &net_namespace_list);
149 mutex_unlock(&net_mutex);
154 new_net = ERR_PTR(err);
159 static int __init net_ns_init(void)
163 printk(KERN_INFO "net_namespace: %zd bytes\n", sizeof(struct net));
164 net_cachep = kmem_cache_create("net_namespace", sizeof(struct net),
167 mutex_lock(&net_mutex);
168 err = setup_net(&init_net);
171 list_add_tail(&init_net.list, &net_namespace_list);
174 mutex_unlock(&net_mutex);
176 panic("Could not setup the initial network namespace");
181 pure_initcall(net_ns_init);
183 static int register_pernet_operations(struct list_head *list,
184 struct pernet_operations *ops)
186 struct net *net, *undo_net;
190 list_add_tail(&ops->list, list);
193 error = ops->init(net);
202 /* If I have an error cleanup all namespaces I initialized */
203 list_del(&ops->list);
204 for_each_net(undo_net) {
214 static void unregister_pernet_operations(struct pernet_operations *ops)
218 list_del(&ops->list);
225 * register_pernet_subsys - register a network namespace subsystem
226 * @ops: pernet operations structure for the subsystem
228 * Register a subsystem which has init and exit functions
229 * that are called when network namespaces are created and
230 * destroyed respectively.
232 * When registered all network namespace init functions are
233 * called for every existing network namespace. Allowing kernel
234 * modules to have a race free view of the set of network namespaces.
236 * When a new network namespace is created all of the init
237 * methods are called in the order in which they were registered.
239 * When a network namespace is destroyed all of the exit methods
240 * are called in the reverse of the order with which they were
243 int register_pernet_subsys(struct pernet_operations *ops)
246 mutex_lock(&net_mutex);
247 error = register_pernet_operations(first_device, ops);
248 mutex_unlock(&net_mutex);
251 EXPORT_SYMBOL_GPL(register_pernet_subsys);
254 * unregister_pernet_subsys - unregister a network namespace subsystem
255 * @ops: pernet operations structure to manipulate
257 * Remove the pernet operations structure from the list to be
258 * used when network namespaces are created or destoryed. In
259 * addition run the exit method for all existing network
262 void unregister_pernet_subsys(struct pernet_operations *module)
264 mutex_lock(&net_mutex);
265 unregister_pernet_operations(module);
266 mutex_unlock(&net_mutex);
268 EXPORT_SYMBOL_GPL(unregister_pernet_subsys);
271 * register_pernet_device - register a network namespace device
272 * @ops: pernet operations structure for the subsystem
274 * Register a device which has init and exit functions
275 * that are called when network namespaces are created and
276 * destroyed respectively.
278 * When registered all network namespace init functions are
279 * called for every existing network namespace. Allowing kernel
280 * modules to have a race free view of the set of network namespaces.
282 * When a new network namespace is created all of the init
283 * methods are called in the order in which they were registered.
285 * When a network namespace is destroyed all of the exit methods
286 * are called in the reverse of the order with which they were
289 int register_pernet_device(struct pernet_operations *ops)
292 mutex_lock(&net_mutex);
293 error = register_pernet_operations(&pernet_list, ops);
294 if (!error && (first_device == &pernet_list))
295 first_device = &ops->list;
296 mutex_unlock(&net_mutex);
299 EXPORT_SYMBOL_GPL(register_pernet_device);
302 * unregister_pernet_device - unregister a network namespace netdevice
303 * @ops: pernet operations structure to manipulate
305 * Remove the pernet operations structure from the list to be
306 * used when network namespaces are created or destoryed. In
307 * addition run the exit method for all existing network
310 void unregister_pernet_device(struct pernet_operations *ops)
312 mutex_lock(&net_mutex);
313 if (&ops->list == first_device)
314 first_device = first_device->next;
315 unregister_pernet_operations(ops);
316 mutex_unlock(&net_mutex);
318 EXPORT_SYMBOL_GPL(unregister_pernet_device);