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1#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
2
3#include <linux/workqueue.h>
4#include <linux/rtnetlink.h>
5#include <linux/cache.h>
6#include <linux/slab.h>
7#include <linux/list.h>
8#include <linux/delay.h>
9#include <linux/sched.h>
10#include <linux/idr.h>
11#include <linux/rculist.h>
12#include <linux/nsproxy.h>
13#include <linux/fs.h>
14#include <linux/proc_ns.h>
15#include <linux/file.h>
16#include <linux/export.h>
17#include <linux/user_namespace.h>
18#include <net/net_namespace.h>
19#include <net/netns/generic.h>
20
21/*
22 * Our network namespace constructor/destructor lists
23 */
24
25static LIST_HEAD(pernet_list);
26static struct list_head *first_device = &pernet_list;
27DEFINE_MUTEX(net_mutex);
28
29LIST_HEAD(net_namespace_list);
30EXPORT_SYMBOL_GPL(net_namespace_list);
31
32struct net init_net = {
33 .dev_base_head = LIST_HEAD_INIT(init_net.dev_base_head),
34};
35EXPORT_SYMBOL(init_net);
36
37#define INITIAL_NET_GEN_PTRS 13 /* +1 for len +2 for rcu_head */
38
39static unsigned int max_gen_ptrs = INITIAL_NET_GEN_PTRS;
40
41static struct net_generic *net_alloc_generic(void)
42{
43 struct net_generic *ng;
44 size_t generic_size = offsetof(struct net_generic, ptr[max_gen_ptrs]);
45
46 ng = kzalloc(generic_size, GFP_KERNEL);
47 if (ng)
48 ng->len = max_gen_ptrs;
49
50 return ng;
51}
52
53static int net_assign_generic(struct net *net, int id, void *data)
54{
55 struct net_generic *ng, *old_ng;
56
57 BUG_ON(!mutex_is_locked(&net_mutex));
58 BUG_ON(id == 0);
59
60 old_ng = rcu_dereference_protected(net->gen,
61 lockdep_is_held(&net_mutex));
62 ng = old_ng;
63 if (old_ng->len >= id)
64 goto assign;
65
66 ng = net_alloc_generic();
67 if (ng == NULL)
68 return -ENOMEM;
69
70 /*
71 * Some synchronisation notes:
72 *
73 * The net_generic explores the net->gen array inside rcu
74 * read section. Besides once set the net->gen->ptr[x]
75 * pointer never changes (see rules in netns/generic.h).
76 *
77 * That said, we simply duplicate this array and schedule
78 * the old copy for kfree after a grace period.
79 */
80
81 memcpy(&ng->ptr, &old_ng->ptr, old_ng->len * sizeof(void*));
82
83 rcu_assign_pointer(net->gen, ng);
84 kfree_rcu(old_ng, rcu);
85assign:
86 ng->ptr[id - 1] = data;
87 return 0;
88}
89
90static int ops_init(const struct pernet_operations *ops, struct net *net)
91{
92 int err = -ENOMEM;
93 void *data = NULL;
94
95 if (ops->id && ops->size) {
96 data = kzalloc(ops->size, GFP_KERNEL);
97 if (!data)
98 goto out;
99
100 err = net_assign_generic(net, *ops->id, data);
101 if (err)
102 goto cleanup;
103 }
104 err = 0;
105 if (ops->init)
106 err = ops->init(net);
107 if (!err)
108 return 0;
109
110cleanup:
111 kfree(data);
112
113out:
114 return err;
115}
116
117static void ops_free(const struct pernet_operations *ops, struct net *net)
118{
119 if (ops->id && ops->size) {
120 int id = *ops->id;
121 kfree(net_generic(net, id));
122 }
123}
124
125static void ops_exit_list(const struct pernet_operations *ops,
126 struct list_head *net_exit_list)
127{
128 struct net *net;
129 if (ops->exit) {
130 list_for_each_entry(net, net_exit_list, exit_list)
131 ops->exit(net);
132 }
133 if (ops->exit_batch)
134 ops->exit_batch(net_exit_list);
135}
136
137static void ops_free_list(const struct pernet_operations *ops,
138 struct list_head *net_exit_list)
139{
140 struct net *net;
141 if (ops->size && ops->id) {
142 list_for_each_entry(net, net_exit_list, exit_list)
143 ops_free(ops, net);
144 }
145}
146
147/*
148 * setup_net runs the initializers for the network namespace object.
149 */
150static __net_init int setup_net(struct net *net, struct user_namespace *user_ns)
151{
152 /* Must be called with net_mutex held */
153 const struct pernet_operations *ops, *saved_ops;
154 int error = 0;
155 LIST_HEAD(net_exit_list);
156
157 atomic_set(&net->count, 1);
158 atomic_set(&net->passive, 1);
159 net->dev_base_seq = 1;
160 net->user_ns = user_ns;
161
162#ifdef NETNS_REFCNT_DEBUG
163 atomic_set(&net->use_count, 0);
164#endif
165
166 list_for_each_entry(ops, &pernet_list, list) {
167 error = ops_init(ops, net);
168 if (error < 0)
169 goto out_undo;
170 }
171out:
172 return error;
173
174out_undo:
175 /* Walk through the list backwards calling the exit functions
176 * for the pernet modules whose init functions did not fail.
177 */
178 list_add(&net->exit_list, &net_exit_list);
179 saved_ops = ops;
180 list_for_each_entry_continue_reverse(ops, &pernet_list, list)
181 ops_exit_list(ops, &net_exit_list);
182
183 ops = saved_ops;
184 list_for_each_entry_continue_reverse(ops, &pernet_list, list)
185 ops_free_list(ops, &net_exit_list);
186
187 rcu_barrier();
188 goto out;
189}
190
191
192#ifdef CONFIG_NET_NS
193static struct kmem_cache *net_cachep;
194static struct workqueue_struct *netns_wq;
195
196static struct net *net_alloc(void)
197{
198 struct net *net = NULL;
199 struct net_generic *ng;
200
201 ng = net_alloc_generic();
202 if (!ng)
203 goto out;
204
205 net = kmem_cache_zalloc(net_cachep, GFP_KERNEL);
206 if (!net)
207 goto out_free;
208
209 rcu_assign_pointer(net->gen, ng);
210out:
211 return net;
212
213out_free:
214 kfree(ng);
215 goto out;
216}
217
218static void net_free(struct net *net)
219{
220#ifdef NETNS_REFCNT_DEBUG
221 if (unlikely(atomic_read(&net->use_count) != 0)) {
222 pr_emerg("network namespace not free! Usage: %d\n",
223 atomic_read(&net->use_count));
224 return;
225 }
226#endif
227 kfree(net->gen);
228 kmem_cache_free(net_cachep, net);
229}
230
231void net_drop_ns(void *p)
232{
233 struct net *ns = p;
234 if (ns && atomic_dec_and_test(&ns->passive))
235 net_free(ns);
236}
237
238struct net *copy_net_ns(unsigned long flags,
239 struct user_namespace *user_ns, struct net *old_net)
240{
241 struct net *net;
242 int rv;
243
244 if (!(flags & CLONE_NEWNET))
245 return get_net(old_net);
246
247 net = net_alloc();
248 if (!net)
249 return ERR_PTR(-ENOMEM);
250
251 get_user_ns(user_ns);
252
253 mutex_lock(&net_mutex);
254 rv = setup_net(net, user_ns);
255 if (rv == 0) {
256 rtnl_lock();
257 list_add_tail_rcu(&net->list, &net_namespace_list);
258 rtnl_unlock();
259 }
260 mutex_unlock(&net_mutex);
261 if (rv < 0) {
262 put_user_ns(user_ns);
263 net_drop_ns(net);
264 return ERR_PTR(rv);
265 }
266 return net;
267}
268
269static DEFINE_SPINLOCK(cleanup_list_lock);
270static LIST_HEAD(cleanup_list); /* Must hold cleanup_list_lock to touch */
271
272static void cleanup_net(struct work_struct *work)
273{
274 const struct pernet_operations *ops;
275 struct net *net, *tmp;
276 LIST_HEAD(net_kill_list);
277 LIST_HEAD(net_exit_list);
278
279 /* Atomically snapshot the list of namespaces to cleanup */
280 spin_lock_irq(&cleanup_list_lock);
281 list_replace_init(&cleanup_list, &net_kill_list);
282 spin_unlock_irq(&cleanup_list_lock);
283
284 mutex_lock(&net_mutex);
285
286 /* Don't let anyone else find us. */
287 rtnl_lock();
288 list_for_each_entry(net, &net_kill_list, cleanup_list) {
289 list_del_rcu(&net->list);
290 list_add_tail(&net->exit_list, &net_exit_list);
291 }
292 rtnl_unlock();
293
294 /*
295 * Another CPU might be rcu-iterating the list, wait for it.
296 * This needs to be before calling the exit() notifiers, so
297 * the rcu_barrier() below isn't sufficient alone.
298 */
299 synchronize_rcu();
300
301 /* Run all of the network namespace exit methods */
302 list_for_each_entry_reverse(ops, &pernet_list, list)
303 ops_exit_list(ops, &net_exit_list);
304
305 /* Free the net generic variables */
306 list_for_each_entry_reverse(ops, &pernet_list, list)
307 ops_free_list(ops, &net_exit_list);
308
309 mutex_unlock(&net_mutex);
310
311 /* Ensure there are no outstanding rcu callbacks using this
312 * network namespace.
313 */
314 rcu_barrier();
315
316 /* Finally it is safe to free my network namespace structure */
317 list_for_each_entry_safe(net, tmp, &net_exit_list, exit_list) {
318 list_del_init(&net->exit_list);
319 put_user_ns(net->user_ns);
320 net_drop_ns(net);
321 }
322}
323static DECLARE_WORK(net_cleanup_work, cleanup_net);
324
325void __put_net(struct net *net)
326{
327 /* Cleanup the network namespace in process context */
328 unsigned long flags;
329
330 spin_lock_irqsave(&cleanup_list_lock, flags);
331 list_add(&net->cleanup_list, &cleanup_list);
332 spin_unlock_irqrestore(&cleanup_list_lock, flags);
333
334 queue_work(netns_wq, &net_cleanup_work);
335}
336EXPORT_SYMBOL_GPL(__put_net);
337
338struct net *get_net_ns_by_fd(int fd)
339{
340 struct proc_ns *ei;
341 struct file *file;
342 struct net *net;
343
344 file = proc_ns_fget(fd);
345 if (IS_ERR(file))
346 return ERR_CAST(file);
347
348 ei = get_proc_ns(file_inode(file));
349 if (ei->ns_ops == &netns_operations)
350 net = get_net(ei->ns);
351 else
352 net = ERR_PTR(-EINVAL);
353
354 fput(file);
355 return net;
356}
357
358#else
359struct net *get_net_ns_by_fd(int fd)
360{
361 return ERR_PTR(-EINVAL);
362}
363#endif
364
365struct net *get_net_ns_by_pid(pid_t pid)
366{
367 struct task_struct *tsk;
368 struct net *net;
369
370 /* Lookup the network namespace */
371 net = ERR_PTR(-ESRCH);
372 rcu_read_lock();
373 tsk = find_task_by_vpid(pid);
374 if (tsk) {
375 struct nsproxy *nsproxy;
376 nsproxy = task_nsproxy(tsk);
377 if (nsproxy)
378 net = get_net(nsproxy->net_ns);
379 }
380 rcu_read_unlock();
381 return net;
382}
383EXPORT_SYMBOL_GPL(get_net_ns_by_pid);
384
385static __net_init int net_ns_net_init(struct net *net)
386{
387 return proc_alloc_inum(&net->proc_inum);
388}
389
390static __net_exit void net_ns_net_exit(struct net *net)
391{
392 proc_free_inum(net->proc_inum);
393}
394
395static struct pernet_operations __net_initdata net_ns_ops = {
396 .init = net_ns_net_init,
397 .exit = net_ns_net_exit,
398};
399
400static int __init net_ns_init(void)
401{
402 struct net_generic *ng;
403
404#ifdef CONFIG_NET_NS
405 net_cachep = kmem_cache_create("net_namespace", sizeof(struct net),
406 SMP_CACHE_BYTES,
407 SLAB_PANIC, NULL);
408
409 /* Create workqueue for cleanup */
410 netns_wq = create_singlethread_workqueue("netns");
411 if (!netns_wq)
412 panic("Could not create netns workq");
413#endif
414
415 ng = net_alloc_generic();
416 if (!ng)
417 panic("Could not allocate generic netns");
418
419 rcu_assign_pointer(init_net.gen, ng);
420
421 mutex_lock(&net_mutex);
422 if (setup_net(&init_net, &init_user_ns))
423 panic("Could not setup the initial network namespace");
424
425 rtnl_lock();
426 list_add_tail_rcu(&init_net.list, &net_namespace_list);
427 rtnl_unlock();
428
429 mutex_unlock(&net_mutex);
430
431 register_pernet_subsys(&net_ns_ops);
432
433 return 0;
434}
435
436pure_initcall(net_ns_init);
437
438#ifdef CONFIG_NET_NS
439static int __register_pernet_operations(struct list_head *list,
440 struct pernet_operations *ops)
441{
442 struct net *net;
443 int error;
444 LIST_HEAD(net_exit_list);
445
446 list_add_tail(&ops->list, list);
447 if (ops->init || (ops->id && ops->size)) {
448 for_each_net(net) {
449 error = ops_init(ops, net);
450 if (error)
451 goto out_undo;
452 list_add_tail(&net->exit_list, &net_exit_list);
453 }
454 }
455 return 0;
456
457out_undo:
458 /* If I have an error cleanup all namespaces I initialized */
459 list_del(&ops->list);
460 ops_exit_list(ops, &net_exit_list);
461 ops_free_list(ops, &net_exit_list);
462 return error;
463}
464
465static void __unregister_pernet_operations(struct pernet_operations *ops)
466{
467 struct net *net;
468 LIST_HEAD(net_exit_list);
469
470 list_del(&ops->list);
471 for_each_net(net)
472 list_add_tail(&net->exit_list, &net_exit_list);
473 ops_exit_list(ops, &net_exit_list);
474 ops_free_list(ops, &net_exit_list);
475}
476
477#else
478
479static int __register_pernet_operations(struct list_head *list,
480 struct pernet_operations *ops)
481{
482 return ops_init(ops, &init_net);
483}
484
485static void __unregister_pernet_operations(struct pernet_operations *ops)
486{
487 LIST_HEAD(net_exit_list);
488 list_add(&init_net.exit_list, &net_exit_list);
489 ops_exit_list(ops, &net_exit_list);
490 ops_free_list(ops, &net_exit_list);
491}
492
493#endif /* CONFIG_NET_NS */
494
495static DEFINE_IDA(net_generic_ids);
496
497static int register_pernet_operations(struct list_head *list,
498 struct pernet_operations *ops)
499{
500 int error;
501
502 if (ops->id) {
503again:
504 error = ida_get_new_above(&net_generic_ids, 1, ops->id);
505 if (error < 0) {
506 if (error == -EAGAIN) {
507 ida_pre_get(&net_generic_ids, GFP_KERNEL);
508 goto again;
509 }
510 return error;
511 }
512 max_gen_ptrs = max_t(unsigned int, max_gen_ptrs, *ops->id);
513 }
514 error = __register_pernet_operations(list, ops);
515 if (error) {
516 rcu_barrier();
517 if (ops->id)
518 ida_remove(&net_generic_ids, *ops->id);
519 }
520
521 return error;
522}
523
524static void unregister_pernet_operations(struct pernet_operations *ops)
525{
526
527 __unregister_pernet_operations(ops);
528 rcu_barrier();
529 if (ops->id)
530 ida_remove(&net_generic_ids, *ops->id);
531}
532
533/**
534 * register_pernet_subsys - register a network namespace subsystem
535 * @ops: pernet operations structure for the subsystem
536 *
537 * Register a subsystem which has init and exit functions
538 * that are called when network namespaces are created and
539 * destroyed respectively.
540 *
541 * When registered all network namespace init functions are
542 * called for every existing network namespace. Allowing kernel
543 * modules to have a race free view of the set of network namespaces.
544 *
545 * When a new network namespace is created all of the init
546 * methods are called in the order in which they were registered.
547 *
548 * When a network namespace is destroyed all of the exit methods
549 * are called in the reverse of the order with which they were
550 * registered.
551 */
552int register_pernet_subsys(struct pernet_operations *ops)
553{
554 int error;
555 mutex_lock(&net_mutex);
556 error = register_pernet_operations(first_device, ops);
557 mutex_unlock(&net_mutex);
558 return error;
559}
560EXPORT_SYMBOL_GPL(register_pernet_subsys);
561
562/**
563 * unregister_pernet_subsys - unregister a network namespace subsystem
564 * @ops: pernet operations structure to manipulate
565 *
566 * Remove the pernet operations structure from the list to be
567 * used when network namespaces are created or destroyed. In
568 * addition run the exit method for all existing network
569 * namespaces.
570 */
571void unregister_pernet_subsys(struct pernet_operations *ops)
572{
573 mutex_lock(&net_mutex);
574 unregister_pernet_operations(ops);
575 mutex_unlock(&net_mutex);
576}
577EXPORT_SYMBOL_GPL(unregister_pernet_subsys);
578
579/**
580 * register_pernet_device - register a network namespace device
581 * @ops: pernet operations structure for the subsystem
582 *
583 * Register a device which has init and exit functions
584 * that are called when network namespaces are created and
585 * destroyed respectively.
586 *
587 * When registered all network namespace init functions are
588 * called for every existing network namespace. Allowing kernel
589 * modules to have a race free view of the set of network namespaces.
590 *
591 * When a new network namespace is created all of the init
592 * methods are called in the order in which they were registered.
593 *
594 * When a network namespace is destroyed all of the exit methods
595 * are called in the reverse of the order with which they were
596 * registered.
597 */
598int register_pernet_device(struct pernet_operations *ops)
599{
600 int error;
601 mutex_lock(&net_mutex);
602 error = register_pernet_operations(&pernet_list, ops);
603 if (!error && (first_device == &pernet_list))
604 first_device = &ops->list;
605 mutex_unlock(&net_mutex);
606 return error;
607}
608EXPORT_SYMBOL_GPL(register_pernet_device);
609
610/**
611 * unregister_pernet_device - unregister a network namespace netdevice
612 * @ops: pernet operations structure to manipulate
613 *
614 * Remove the pernet operations structure from the list to be
615 * used when network namespaces are created or destroyed. In
616 * addition run the exit method for all existing network
617 * namespaces.
618 */
619void unregister_pernet_device(struct pernet_operations *ops)
620{
621 mutex_lock(&net_mutex);
622 if (&ops->list == first_device)
623 first_device = first_device->next;
624 unregister_pernet_operations(ops);
625 mutex_unlock(&net_mutex);
626}
627EXPORT_SYMBOL_GPL(unregister_pernet_device);
628
629#ifdef CONFIG_NET_NS
630static void *netns_get(struct task_struct *task)
631{
632 struct net *net = NULL;
633 struct nsproxy *nsproxy;
634
635 rcu_read_lock();
636 nsproxy = task_nsproxy(task);
637 if (nsproxy)
638 net = get_net(nsproxy->net_ns);
639 rcu_read_unlock();
640
641 return net;
642}
643
644static void netns_put(void *ns)
645{
646 put_net(ns);
647}
648
649static int netns_install(struct nsproxy *nsproxy, void *ns)
650{
651 struct net *net = ns;
652
653 if (!ns_capable(net->user_ns, CAP_SYS_ADMIN) ||
654 !ns_capable(current_user_ns(), CAP_SYS_ADMIN))
655 return -EPERM;
656
657 put_net(nsproxy->net_ns);
658 nsproxy->net_ns = get_net(net);
659 return 0;
660}
661
662static unsigned int netns_inum(void *ns)
663{
664 struct net *net = ns;
665 return net->proc_inum;
666}
667
668const struct proc_ns_operations netns_operations = {
669 .name = "net",
670 .type = CLONE_NEWNET,
671 .get = netns_get,
672 .put = netns_put,
673 .install = netns_install,
674 .inum = netns_inum,
675};
676#endif
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 <linux/idr.h>
9#include <linux/rculist.h>
10#include <linux/nsproxy.h>
11#include <linux/proc_fs.h>
12#include <linux/file.h>
13#include <net/net_namespace.h>
14#include <net/netns/generic.h>
15
16/*
17 * Our network namespace constructor/destructor lists
18 */
19
20static LIST_HEAD(pernet_list);
21static struct list_head *first_device = &pernet_list;
22static DEFINE_MUTEX(net_mutex);
23
24LIST_HEAD(net_namespace_list);
25EXPORT_SYMBOL_GPL(net_namespace_list);
26
27struct net init_net;
28EXPORT_SYMBOL(init_net);
29
30#define INITIAL_NET_GEN_PTRS 13 /* +1 for len +2 for rcu_head */
31
32static int net_assign_generic(struct net *net, int id, void *data)
33{
34 struct net_generic *ng, *old_ng;
35
36 BUG_ON(!mutex_is_locked(&net_mutex));
37 BUG_ON(id == 0);
38
39 old_ng = rcu_dereference_protected(net->gen,
40 lockdep_is_held(&net_mutex));
41 ng = old_ng;
42 if (old_ng->len >= id)
43 goto assign;
44
45 ng = kzalloc(sizeof(struct net_generic) +
46 id * sizeof(void *), GFP_KERNEL);
47 if (ng == NULL)
48 return -ENOMEM;
49
50 /*
51 * Some synchronisation notes:
52 *
53 * The net_generic explores the net->gen array inside rcu
54 * read section. Besides once set the net->gen->ptr[x]
55 * pointer never changes (see rules in netns/generic.h).
56 *
57 * That said, we simply duplicate this array and schedule
58 * the old copy for kfree after a grace period.
59 */
60
61 ng->len = id;
62 memcpy(&ng->ptr, &old_ng->ptr, old_ng->len * sizeof(void*));
63
64 rcu_assign_pointer(net->gen, ng);
65 kfree_rcu(old_ng, rcu);
66assign:
67 ng->ptr[id - 1] = data;
68 return 0;
69}
70
71static int ops_init(const struct pernet_operations *ops, struct net *net)
72{
73 int err;
74 if (ops->id && ops->size) {
75 void *data = kzalloc(ops->size, GFP_KERNEL);
76 if (!data)
77 return -ENOMEM;
78
79 err = net_assign_generic(net, *ops->id, data);
80 if (err) {
81 kfree(data);
82 return err;
83 }
84 }
85 if (ops->init)
86 return ops->init(net);
87 return 0;
88}
89
90static void ops_free(const struct pernet_operations *ops, struct net *net)
91{
92 if (ops->id && ops->size) {
93 int id = *ops->id;
94 kfree(net_generic(net, id));
95 }
96}
97
98static void ops_exit_list(const struct pernet_operations *ops,
99 struct list_head *net_exit_list)
100{
101 struct net *net;
102 if (ops->exit) {
103 list_for_each_entry(net, net_exit_list, exit_list)
104 ops->exit(net);
105 }
106 if (ops->exit_batch)
107 ops->exit_batch(net_exit_list);
108}
109
110static void ops_free_list(const struct pernet_operations *ops,
111 struct list_head *net_exit_list)
112{
113 struct net *net;
114 if (ops->size && ops->id) {
115 list_for_each_entry(net, net_exit_list, exit_list)
116 ops_free(ops, net);
117 }
118}
119
120/*
121 * setup_net runs the initializers for the network namespace object.
122 */
123static __net_init int setup_net(struct net *net)
124{
125 /* Must be called with net_mutex held */
126 const struct pernet_operations *ops, *saved_ops;
127 int error = 0;
128 LIST_HEAD(net_exit_list);
129
130 atomic_set(&net->count, 1);
131 atomic_set(&net->passive, 1);
132 net->dev_base_seq = 1;
133
134#ifdef NETNS_REFCNT_DEBUG
135 atomic_set(&net->use_count, 0);
136#endif
137
138 list_for_each_entry(ops, &pernet_list, list) {
139 error = ops_init(ops, net);
140 if (error < 0)
141 goto out_undo;
142 }
143out:
144 return error;
145
146out_undo:
147 /* Walk through the list backwards calling the exit functions
148 * for the pernet modules whose init functions did not fail.
149 */
150 list_add(&net->exit_list, &net_exit_list);
151 saved_ops = ops;
152 list_for_each_entry_continue_reverse(ops, &pernet_list, list)
153 ops_exit_list(ops, &net_exit_list);
154
155 ops = saved_ops;
156 list_for_each_entry_continue_reverse(ops, &pernet_list, list)
157 ops_free_list(ops, &net_exit_list);
158
159 rcu_barrier();
160 goto out;
161}
162
163static struct net_generic *net_alloc_generic(void)
164{
165 struct net_generic *ng;
166 size_t generic_size = sizeof(struct net_generic) +
167 INITIAL_NET_GEN_PTRS * sizeof(void *);
168
169 ng = kzalloc(generic_size, GFP_KERNEL);
170 if (ng)
171 ng->len = INITIAL_NET_GEN_PTRS;
172
173 return ng;
174}
175
176#ifdef CONFIG_NET_NS
177static struct kmem_cache *net_cachep;
178static struct workqueue_struct *netns_wq;
179
180static struct net *net_alloc(void)
181{
182 struct net *net = NULL;
183 struct net_generic *ng;
184
185 ng = net_alloc_generic();
186 if (!ng)
187 goto out;
188
189 net = kmem_cache_zalloc(net_cachep, GFP_KERNEL);
190 if (!net)
191 goto out_free;
192
193 rcu_assign_pointer(net->gen, ng);
194out:
195 return net;
196
197out_free:
198 kfree(ng);
199 goto out;
200}
201
202static void net_free(struct net *net)
203{
204#ifdef NETNS_REFCNT_DEBUG
205 if (unlikely(atomic_read(&net->use_count) != 0)) {
206 printk(KERN_EMERG "network namespace not free! Usage: %d\n",
207 atomic_read(&net->use_count));
208 return;
209 }
210#endif
211 kfree(net->gen);
212 kmem_cache_free(net_cachep, net);
213}
214
215void net_drop_ns(void *p)
216{
217 struct net *ns = p;
218 if (ns && atomic_dec_and_test(&ns->passive))
219 net_free(ns);
220}
221
222struct net *copy_net_ns(unsigned long flags, struct net *old_net)
223{
224 struct net *net;
225 int rv;
226
227 if (!(flags & CLONE_NEWNET))
228 return get_net(old_net);
229
230 net = net_alloc();
231 if (!net)
232 return ERR_PTR(-ENOMEM);
233 mutex_lock(&net_mutex);
234 rv = setup_net(net);
235 if (rv == 0) {
236 rtnl_lock();
237 list_add_tail_rcu(&net->list, &net_namespace_list);
238 rtnl_unlock();
239 }
240 mutex_unlock(&net_mutex);
241 if (rv < 0) {
242 net_drop_ns(net);
243 return ERR_PTR(rv);
244 }
245 return net;
246}
247
248static DEFINE_SPINLOCK(cleanup_list_lock);
249static LIST_HEAD(cleanup_list); /* Must hold cleanup_list_lock to touch */
250
251static void cleanup_net(struct work_struct *work)
252{
253 const struct pernet_operations *ops;
254 struct net *net, *tmp;
255 LIST_HEAD(net_kill_list);
256 LIST_HEAD(net_exit_list);
257
258 /* Atomically snapshot the list of namespaces to cleanup */
259 spin_lock_irq(&cleanup_list_lock);
260 list_replace_init(&cleanup_list, &net_kill_list);
261 spin_unlock_irq(&cleanup_list_lock);
262
263 mutex_lock(&net_mutex);
264
265 /* Don't let anyone else find us. */
266 rtnl_lock();
267 list_for_each_entry(net, &net_kill_list, cleanup_list) {
268 list_del_rcu(&net->list);
269 list_add_tail(&net->exit_list, &net_exit_list);
270 }
271 rtnl_unlock();
272
273 /*
274 * Another CPU might be rcu-iterating the list, wait for it.
275 * This needs to be before calling the exit() notifiers, so
276 * the rcu_barrier() below isn't sufficient alone.
277 */
278 synchronize_rcu();
279
280 /* Run all of the network namespace exit methods */
281 list_for_each_entry_reverse(ops, &pernet_list, list)
282 ops_exit_list(ops, &net_exit_list);
283
284 /* Free the net generic variables */
285 list_for_each_entry_reverse(ops, &pernet_list, list)
286 ops_free_list(ops, &net_exit_list);
287
288 mutex_unlock(&net_mutex);
289
290 /* Ensure there are no outstanding rcu callbacks using this
291 * network namespace.
292 */
293 rcu_barrier();
294
295 /* Finally it is safe to free my network namespace structure */
296 list_for_each_entry_safe(net, tmp, &net_exit_list, exit_list) {
297 list_del_init(&net->exit_list);
298 net_drop_ns(net);
299 }
300}
301static DECLARE_WORK(net_cleanup_work, cleanup_net);
302
303void __put_net(struct net *net)
304{
305 /* Cleanup the network namespace in process context */
306 unsigned long flags;
307
308 spin_lock_irqsave(&cleanup_list_lock, flags);
309 list_add(&net->cleanup_list, &cleanup_list);
310 spin_unlock_irqrestore(&cleanup_list_lock, flags);
311
312 queue_work(netns_wq, &net_cleanup_work);
313}
314EXPORT_SYMBOL_GPL(__put_net);
315
316struct net *get_net_ns_by_fd(int fd)
317{
318 struct proc_inode *ei;
319 struct file *file;
320 struct net *net;
321
322 file = proc_ns_fget(fd);
323 if (IS_ERR(file))
324 return ERR_CAST(file);
325
326 ei = PROC_I(file->f_dentry->d_inode);
327 if (ei->ns_ops == &netns_operations)
328 net = get_net(ei->ns);
329 else
330 net = ERR_PTR(-EINVAL);
331
332 fput(file);
333 return net;
334}
335
336#else
337struct net *copy_net_ns(unsigned long flags, struct net *old_net)
338{
339 if (flags & CLONE_NEWNET)
340 return ERR_PTR(-EINVAL);
341 return old_net;
342}
343
344struct net *get_net_ns_by_fd(int fd)
345{
346 return ERR_PTR(-EINVAL);
347}
348#endif
349
350struct net *get_net_ns_by_pid(pid_t pid)
351{
352 struct task_struct *tsk;
353 struct net *net;
354
355 /* Lookup the network namespace */
356 net = ERR_PTR(-ESRCH);
357 rcu_read_lock();
358 tsk = find_task_by_vpid(pid);
359 if (tsk) {
360 struct nsproxy *nsproxy;
361 nsproxy = task_nsproxy(tsk);
362 if (nsproxy)
363 net = get_net(nsproxy->net_ns);
364 }
365 rcu_read_unlock();
366 return net;
367}
368EXPORT_SYMBOL_GPL(get_net_ns_by_pid);
369
370static int __init net_ns_init(void)
371{
372 struct net_generic *ng;
373
374#ifdef CONFIG_NET_NS
375 net_cachep = kmem_cache_create("net_namespace", sizeof(struct net),
376 SMP_CACHE_BYTES,
377 SLAB_PANIC, NULL);
378
379 /* Create workqueue for cleanup */
380 netns_wq = create_singlethread_workqueue("netns");
381 if (!netns_wq)
382 panic("Could not create netns workq");
383#endif
384
385 ng = net_alloc_generic();
386 if (!ng)
387 panic("Could not allocate generic netns");
388
389 rcu_assign_pointer(init_net.gen, ng);
390
391 mutex_lock(&net_mutex);
392 if (setup_net(&init_net))
393 panic("Could not setup the initial network namespace");
394
395 rtnl_lock();
396 list_add_tail_rcu(&init_net.list, &net_namespace_list);
397 rtnl_unlock();
398
399 mutex_unlock(&net_mutex);
400
401 return 0;
402}
403
404pure_initcall(net_ns_init);
405
406#ifdef CONFIG_NET_NS
407static int __register_pernet_operations(struct list_head *list,
408 struct pernet_operations *ops)
409{
410 struct net *net;
411 int error;
412 LIST_HEAD(net_exit_list);
413
414 list_add_tail(&ops->list, list);
415 if (ops->init || (ops->id && ops->size)) {
416 for_each_net(net) {
417 error = ops_init(ops, net);
418 if (error)
419 goto out_undo;
420 list_add_tail(&net->exit_list, &net_exit_list);
421 }
422 }
423 return 0;
424
425out_undo:
426 /* If I have an error cleanup all namespaces I initialized */
427 list_del(&ops->list);
428 ops_exit_list(ops, &net_exit_list);
429 ops_free_list(ops, &net_exit_list);
430 return error;
431}
432
433static void __unregister_pernet_operations(struct pernet_operations *ops)
434{
435 struct net *net;
436 LIST_HEAD(net_exit_list);
437
438 list_del(&ops->list);
439 for_each_net(net)
440 list_add_tail(&net->exit_list, &net_exit_list);
441 ops_exit_list(ops, &net_exit_list);
442 ops_free_list(ops, &net_exit_list);
443}
444
445#else
446
447static int __register_pernet_operations(struct list_head *list,
448 struct pernet_operations *ops)
449{
450 int err = 0;
451 err = ops_init(ops, &init_net);
452 if (err)
453 ops_free(ops, &init_net);
454 return err;
455
456}
457
458static void __unregister_pernet_operations(struct pernet_operations *ops)
459{
460 LIST_HEAD(net_exit_list);
461 list_add(&init_net.exit_list, &net_exit_list);
462 ops_exit_list(ops, &net_exit_list);
463 ops_free_list(ops, &net_exit_list);
464}
465
466#endif /* CONFIG_NET_NS */
467
468static DEFINE_IDA(net_generic_ids);
469
470static int register_pernet_operations(struct list_head *list,
471 struct pernet_operations *ops)
472{
473 int error;
474
475 if (ops->id) {
476again:
477 error = ida_get_new_above(&net_generic_ids, 1, ops->id);
478 if (error < 0) {
479 if (error == -EAGAIN) {
480 ida_pre_get(&net_generic_ids, GFP_KERNEL);
481 goto again;
482 }
483 return error;
484 }
485 }
486 error = __register_pernet_operations(list, ops);
487 if (error) {
488 rcu_barrier();
489 if (ops->id)
490 ida_remove(&net_generic_ids, *ops->id);
491 }
492
493 return error;
494}
495
496static void unregister_pernet_operations(struct pernet_operations *ops)
497{
498
499 __unregister_pernet_operations(ops);
500 rcu_barrier();
501 if (ops->id)
502 ida_remove(&net_generic_ids, *ops->id);
503}
504
505/**
506 * register_pernet_subsys - register a network namespace subsystem
507 * @ops: pernet operations structure for the subsystem
508 *
509 * Register a subsystem which has init and exit functions
510 * that are called when network namespaces are created and
511 * destroyed respectively.
512 *
513 * When registered all network namespace init functions are
514 * called for every existing network namespace. Allowing kernel
515 * modules to have a race free view of the set of network namespaces.
516 *
517 * When a new network namespace is created all of the init
518 * methods are called in the order in which they were registered.
519 *
520 * When a network namespace is destroyed all of the exit methods
521 * are called in the reverse of the order with which they were
522 * registered.
523 */
524int register_pernet_subsys(struct pernet_operations *ops)
525{
526 int error;
527 mutex_lock(&net_mutex);
528 error = register_pernet_operations(first_device, ops);
529 mutex_unlock(&net_mutex);
530 return error;
531}
532EXPORT_SYMBOL_GPL(register_pernet_subsys);
533
534/**
535 * unregister_pernet_subsys - unregister a network namespace subsystem
536 * @ops: pernet operations structure to manipulate
537 *
538 * Remove the pernet operations structure from the list to be
539 * used when network namespaces are created or destroyed. In
540 * addition run the exit method for all existing network
541 * namespaces.
542 */
543void unregister_pernet_subsys(struct pernet_operations *ops)
544{
545 mutex_lock(&net_mutex);
546 unregister_pernet_operations(ops);
547 mutex_unlock(&net_mutex);
548}
549EXPORT_SYMBOL_GPL(unregister_pernet_subsys);
550
551/**
552 * register_pernet_device - register a network namespace device
553 * @ops: pernet operations structure for the subsystem
554 *
555 * Register a device which has init and exit functions
556 * that are called when network namespaces are created and
557 * destroyed respectively.
558 *
559 * When registered all network namespace init functions are
560 * called for every existing network namespace. Allowing kernel
561 * modules to have a race free view of the set of network namespaces.
562 *
563 * When a new network namespace is created all of the init
564 * methods are called in the order in which they were registered.
565 *
566 * When a network namespace is destroyed all of the exit methods
567 * are called in the reverse of the order with which they were
568 * registered.
569 */
570int register_pernet_device(struct pernet_operations *ops)
571{
572 int error;
573 mutex_lock(&net_mutex);
574 error = register_pernet_operations(&pernet_list, ops);
575 if (!error && (first_device == &pernet_list))
576 first_device = &ops->list;
577 mutex_unlock(&net_mutex);
578 return error;
579}
580EXPORT_SYMBOL_GPL(register_pernet_device);
581
582/**
583 * unregister_pernet_device - unregister a network namespace netdevice
584 * @ops: pernet operations structure to manipulate
585 *
586 * Remove the pernet operations structure from the list to be
587 * used when network namespaces are created or destroyed. In
588 * addition run the exit method for all existing network
589 * namespaces.
590 */
591void unregister_pernet_device(struct pernet_operations *ops)
592{
593 mutex_lock(&net_mutex);
594 if (&ops->list == first_device)
595 first_device = first_device->next;
596 unregister_pernet_operations(ops);
597 mutex_unlock(&net_mutex);
598}
599EXPORT_SYMBOL_GPL(unregister_pernet_device);
600
601#ifdef CONFIG_NET_NS
602static void *netns_get(struct task_struct *task)
603{
604 struct net *net = NULL;
605 struct nsproxy *nsproxy;
606
607 rcu_read_lock();
608 nsproxy = task_nsproxy(task);
609 if (nsproxy)
610 net = get_net(nsproxy->net_ns);
611 rcu_read_unlock();
612
613 return net;
614}
615
616static void netns_put(void *ns)
617{
618 put_net(ns);
619}
620
621static int netns_install(struct nsproxy *nsproxy, void *ns)
622{
623 put_net(nsproxy->net_ns);
624 nsproxy->net_ns = get_net(ns);
625 return 0;
626}
627
628const struct proc_ns_operations netns_operations = {
629 .name = "net",
630 .type = CLONE_NEWNET,
631 .get = netns_get,
632 .put = netns_put,
633 .install = netns_install,
634};
635#endif