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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 <linux/net_namespace.h>
19#include <net/sock.h>
20#include <net/netlink.h>
21#include <net/net_namespace.h>
22#include <net/netns/generic.h>
23
24/*
25 * Our network namespace constructor/destructor lists
26 */
27
28static LIST_HEAD(pernet_list);
29static struct list_head *first_device = &pernet_list;
30DEFINE_MUTEX(net_mutex);
31
32LIST_HEAD(net_namespace_list);
33EXPORT_SYMBOL_GPL(net_namespace_list);
34
35struct net init_net = {
36 .dev_base_head = LIST_HEAD_INIT(init_net.dev_base_head),
37};
38EXPORT_SYMBOL(init_net);
39
40#define INITIAL_NET_GEN_PTRS 13 /* +1 for len +2 for rcu_head */
41
42static unsigned int max_gen_ptrs = INITIAL_NET_GEN_PTRS;
43
44static struct net_generic *net_alloc_generic(void)
45{
46 struct net_generic *ng;
47 size_t generic_size = offsetof(struct net_generic, ptr[max_gen_ptrs]);
48
49 ng = kzalloc(generic_size, GFP_KERNEL);
50 if (ng)
51 ng->len = max_gen_ptrs;
52
53 return ng;
54}
55
56static int net_assign_generic(struct net *net, int id, void *data)
57{
58 struct net_generic *ng, *old_ng;
59
60 BUG_ON(!mutex_is_locked(&net_mutex));
61 BUG_ON(id == 0);
62
63 old_ng = rcu_dereference_protected(net->gen,
64 lockdep_is_held(&net_mutex));
65 ng = old_ng;
66 if (old_ng->len >= id)
67 goto assign;
68
69 ng = net_alloc_generic();
70 if (ng == NULL)
71 return -ENOMEM;
72
73 /*
74 * Some synchronisation notes:
75 *
76 * The net_generic explores the net->gen array inside rcu
77 * read section. Besides once set the net->gen->ptr[x]
78 * pointer never changes (see rules in netns/generic.h).
79 *
80 * That said, we simply duplicate this array and schedule
81 * the old copy for kfree after a grace period.
82 */
83
84 memcpy(&ng->ptr, &old_ng->ptr, old_ng->len * sizeof(void*));
85
86 rcu_assign_pointer(net->gen, ng);
87 kfree_rcu(old_ng, rcu);
88assign:
89 ng->ptr[id - 1] = data;
90 return 0;
91}
92
93static int ops_init(const struct pernet_operations *ops, struct net *net)
94{
95 int err = -ENOMEM;
96 void *data = NULL;
97
98 if (ops->id && ops->size) {
99 data = kzalloc(ops->size, GFP_KERNEL);
100 if (!data)
101 goto out;
102
103 err = net_assign_generic(net, *ops->id, data);
104 if (err)
105 goto cleanup;
106 }
107 err = 0;
108 if (ops->init)
109 err = ops->init(net);
110 if (!err)
111 return 0;
112
113cleanup:
114 kfree(data);
115
116out:
117 return err;
118}
119
120static void ops_free(const struct pernet_operations *ops, struct net *net)
121{
122 if (ops->id && ops->size) {
123 int id = *ops->id;
124 kfree(net_generic(net, id));
125 }
126}
127
128static void ops_exit_list(const struct pernet_operations *ops,
129 struct list_head *net_exit_list)
130{
131 struct net *net;
132 if (ops->exit) {
133 list_for_each_entry(net, net_exit_list, exit_list)
134 ops->exit(net);
135 }
136 if (ops->exit_batch)
137 ops->exit_batch(net_exit_list);
138}
139
140static void ops_free_list(const struct pernet_operations *ops,
141 struct list_head *net_exit_list)
142{
143 struct net *net;
144 if (ops->size && ops->id) {
145 list_for_each_entry(net, net_exit_list, exit_list)
146 ops_free(ops, net);
147 }
148}
149
150/* should be called with nsid_lock held */
151static int alloc_netid(struct net *net, struct net *peer, int reqid)
152{
153 int min = 0, max = 0;
154
155 if (reqid >= 0) {
156 min = reqid;
157 max = reqid + 1;
158 }
159
160 return idr_alloc(&net->netns_ids, peer, min, max, GFP_ATOMIC);
161}
162
163/* This function is used by idr_for_each(). If net is equal to peer, the
164 * function returns the id so that idr_for_each() stops. Because we cannot
165 * returns the id 0 (idr_for_each() will not stop), we return the magic value
166 * NET_ID_ZERO (-1) for it.
167 */
168#define NET_ID_ZERO -1
169static int net_eq_idr(int id, void *net, void *peer)
170{
171 if (net_eq(net, peer))
172 return id ? : NET_ID_ZERO;
173 return 0;
174}
175
176/* Should be called with nsid_lock held. If a new id is assigned, the bool alloc
177 * is set to true, thus the caller knows that the new id must be notified via
178 * rtnl.
179 */
180static int __peernet2id_alloc(struct net *net, struct net *peer, bool *alloc)
181{
182 int id = idr_for_each(&net->netns_ids, net_eq_idr, peer);
183 bool alloc_it = *alloc;
184
185 *alloc = false;
186
187 /* Magic value for id 0. */
188 if (id == NET_ID_ZERO)
189 return 0;
190 if (id > 0)
191 return id;
192
193 if (alloc_it) {
194 id = alloc_netid(net, peer, -1);
195 *alloc = true;
196 return id >= 0 ? id : NETNSA_NSID_NOT_ASSIGNED;
197 }
198
199 return NETNSA_NSID_NOT_ASSIGNED;
200}
201
202/* should be called with nsid_lock held */
203static int __peernet2id(struct net *net, struct net *peer)
204{
205 bool no = false;
206
207 return __peernet2id_alloc(net, peer, &no);
208}
209
210static void rtnl_net_notifyid(struct net *net, int cmd, int id);
211/* This function returns the id of a peer netns. If no id is assigned, one will
212 * be allocated and returned.
213 */
214int peernet2id_alloc(struct net *net, struct net *peer)
215{
216 unsigned long flags;
217 bool alloc;
218 int id;
219
220 spin_lock_irqsave(&net->nsid_lock, flags);
221 alloc = atomic_read(&peer->count) == 0 ? false : true;
222 id = __peernet2id_alloc(net, peer, &alloc);
223 spin_unlock_irqrestore(&net->nsid_lock, flags);
224 if (alloc && id >= 0)
225 rtnl_net_notifyid(net, RTM_NEWNSID, id);
226 return id;
227}
228EXPORT_SYMBOL(peernet2id_alloc);
229
230/* This function returns, if assigned, the id of a peer netns. */
231int peernet2id(struct net *net, struct net *peer)
232{
233 unsigned long flags;
234 int id;
235
236 spin_lock_irqsave(&net->nsid_lock, flags);
237 id = __peernet2id(net, peer);
238 spin_unlock_irqrestore(&net->nsid_lock, flags);
239 return id;
240}
241
242/* This function returns true is the peer netns has an id assigned into the
243 * current netns.
244 */
245bool peernet_has_id(struct net *net, struct net *peer)
246{
247 return peernet2id(net, peer) >= 0;
248}
249
250struct net *get_net_ns_by_id(struct net *net, int id)
251{
252 unsigned long flags;
253 struct net *peer;
254
255 if (id < 0)
256 return NULL;
257
258 rcu_read_lock();
259 spin_lock_irqsave(&net->nsid_lock, flags);
260 peer = idr_find(&net->netns_ids, id);
261 if (peer)
262 get_net(peer);
263 spin_unlock_irqrestore(&net->nsid_lock, flags);
264 rcu_read_unlock();
265
266 return peer;
267}
268
269/*
270 * setup_net runs the initializers for the network namespace object.
271 */
272static __net_init int setup_net(struct net *net, struct user_namespace *user_ns)
273{
274 /* Must be called with net_mutex held */
275 const struct pernet_operations *ops, *saved_ops;
276 int error = 0;
277 LIST_HEAD(net_exit_list);
278
279 atomic_set(&net->count, 1);
280 atomic_set(&net->passive, 1);
281 net->dev_base_seq = 1;
282 net->user_ns = user_ns;
283 idr_init(&net->netns_ids);
284 spin_lock_init(&net->nsid_lock);
285
286 list_for_each_entry(ops, &pernet_list, list) {
287 error = ops_init(ops, net);
288 if (error < 0)
289 goto out_undo;
290 }
291out:
292 return error;
293
294out_undo:
295 /* Walk through the list backwards calling the exit functions
296 * for the pernet modules whose init functions did not fail.
297 */
298 list_add(&net->exit_list, &net_exit_list);
299 saved_ops = ops;
300 list_for_each_entry_continue_reverse(ops, &pernet_list, list)
301 ops_exit_list(ops, &net_exit_list);
302
303 ops = saved_ops;
304 list_for_each_entry_continue_reverse(ops, &pernet_list, list)
305 ops_free_list(ops, &net_exit_list);
306
307 rcu_barrier();
308 goto out;
309}
310
311
312#ifdef CONFIG_NET_NS
313static struct kmem_cache *net_cachep;
314static struct workqueue_struct *netns_wq;
315
316static struct net *net_alloc(void)
317{
318 struct net *net = NULL;
319 struct net_generic *ng;
320
321 ng = net_alloc_generic();
322 if (!ng)
323 goto out;
324
325 net = kmem_cache_zalloc(net_cachep, GFP_KERNEL);
326 if (!net)
327 goto out_free;
328
329 rcu_assign_pointer(net->gen, ng);
330out:
331 return net;
332
333out_free:
334 kfree(ng);
335 goto out;
336}
337
338static void net_free(struct net *net)
339{
340 kfree(rcu_access_pointer(net->gen));
341 kmem_cache_free(net_cachep, net);
342}
343
344void net_drop_ns(void *p)
345{
346 struct net *ns = p;
347 if (ns && atomic_dec_and_test(&ns->passive))
348 net_free(ns);
349}
350
351struct net *copy_net_ns(unsigned long flags,
352 struct user_namespace *user_ns, struct net *old_net)
353{
354 struct net *net;
355 int rv;
356
357 if (!(flags & CLONE_NEWNET))
358 return get_net(old_net);
359
360 net = net_alloc();
361 if (!net)
362 return ERR_PTR(-ENOMEM);
363
364 get_user_ns(user_ns);
365
366 mutex_lock(&net_mutex);
367 rv = setup_net(net, user_ns);
368 if (rv == 0) {
369 rtnl_lock();
370 list_add_tail_rcu(&net->list, &net_namespace_list);
371 rtnl_unlock();
372 }
373 mutex_unlock(&net_mutex);
374 if (rv < 0) {
375 put_user_ns(user_ns);
376 net_drop_ns(net);
377 return ERR_PTR(rv);
378 }
379 return net;
380}
381
382static DEFINE_SPINLOCK(cleanup_list_lock);
383static LIST_HEAD(cleanup_list); /* Must hold cleanup_list_lock to touch */
384
385static void cleanup_net(struct work_struct *work)
386{
387 const struct pernet_operations *ops;
388 struct net *net, *tmp;
389 struct list_head net_kill_list;
390 LIST_HEAD(net_exit_list);
391
392 /* Atomically snapshot the list of namespaces to cleanup */
393 spin_lock_irq(&cleanup_list_lock);
394 list_replace_init(&cleanup_list, &net_kill_list);
395 spin_unlock_irq(&cleanup_list_lock);
396
397 mutex_lock(&net_mutex);
398
399 /* Don't let anyone else find us. */
400 rtnl_lock();
401 list_for_each_entry(net, &net_kill_list, cleanup_list) {
402 list_del_rcu(&net->list);
403 list_add_tail(&net->exit_list, &net_exit_list);
404 for_each_net(tmp) {
405 int id;
406
407 spin_lock_irq(&tmp->nsid_lock);
408 id = __peernet2id(tmp, net);
409 if (id >= 0)
410 idr_remove(&tmp->netns_ids, id);
411 spin_unlock_irq(&tmp->nsid_lock);
412 if (id >= 0)
413 rtnl_net_notifyid(tmp, RTM_DELNSID, id);
414 }
415 spin_lock_irq(&net->nsid_lock);
416 idr_destroy(&net->netns_ids);
417 spin_unlock_irq(&net->nsid_lock);
418
419 }
420 rtnl_unlock();
421
422 /*
423 * Another CPU might be rcu-iterating the list, wait for it.
424 * This needs to be before calling the exit() notifiers, so
425 * the rcu_barrier() below isn't sufficient alone.
426 */
427 synchronize_rcu();
428
429 /* Run all of the network namespace exit methods */
430 list_for_each_entry_reverse(ops, &pernet_list, list)
431 ops_exit_list(ops, &net_exit_list);
432
433 /* Free the net generic variables */
434 list_for_each_entry_reverse(ops, &pernet_list, list)
435 ops_free_list(ops, &net_exit_list);
436
437 mutex_unlock(&net_mutex);
438
439 /* Ensure there are no outstanding rcu callbacks using this
440 * network namespace.
441 */
442 rcu_barrier();
443
444 /* Finally it is safe to free my network namespace structure */
445 list_for_each_entry_safe(net, tmp, &net_exit_list, exit_list) {
446 list_del_init(&net->exit_list);
447 put_user_ns(net->user_ns);
448 net_drop_ns(net);
449 }
450}
451static DECLARE_WORK(net_cleanup_work, cleanup_net);
452
453void __put_net(struct net *net)
454{
455 /* Cleanup the network namespace in process context */
456 unsigned long flags;
457
458 spin_lock_irqsave(&cleanup_list_lock, flags);
459 list_add(&net->cleanup_list, &cleanup_list);
460 spin_unlock_irqrestore(&cleanup_list_lock, flags);
461
462 queue_work(netns_wq, &net_cleanup_work);
463}
464EXPORT_SYMBOL_GPL(__put_net);
465
466struct net *get_net_ns_by_fd(int fd)
467{
468 struct file *file;
469 struct ns_common *ns;
470 struct net *net;
471
472 file = proc_ns_fget(fd);
473 if (IS_ERR(file))
474 return ERR_CAST(file);
475
476 ns = get_proc_ns(file_inode(file));
477 if (ns->ops == &netns_operations)
478 net = get_net(container_of(ns, struct net, ns));
479 else
480 net = ERR_PTR(-EINVAL);
481
482 fput(file);
483 return net;
484}
485
486#else
487struct net *get_net_ns_by_fd(int fd)
488{
489 return ERR_PTR(-EINVAL);
490}
491#endif
492EXPORT_SYMBOL_GPL(get_net_ns_by_fd);
493
494struct net *get_net_ns_by_pid(pid_t pid)
495{
496 struct task_struct *tsk;
497 struct net *net;
498
499 /* Lookup the network namespace */
500 net = ERR_PTR(-ESRCH);
501 rcu_read_lock();
502 tsk = find_task_by_vpid(pid);
503 if (tsk) {
504 struct nsproxy *nsproxy;
505 task_lock(tsk);
506 nsproxy = tsk->nsproxy;
507 if (nsproxy)
508 net = get_net(nsproxy->net_ns);
509 task_unlock(tsk);
510 }
511 rcu_read_unlock();
512 return net;
513}
514EXPORT_SYMBOL_GPL(get_net_ns_by_pid);
515
516static __net_init int net_ns_net_init(struct net *net)
517{
518#ifdef CONFIG_NET_NS
519 net->ns.ops = &netns_operations;
520#endif
521 return ns_alloc_inum(&net->ns);
522}
523
524static __net_exit void net_ns_net_exit(struct net *net)
525{
526 ns_free_inum(&net->ns);
527}
528
529static struct pernet_operations __net_initdata net_ns_ops = {
530 .init = net_ns_net_init,
531 .exit = net_ns_net_exit,
532};
533
534static struct nla_policy rtnl_net_policy[NETNSA_MAX + 1] = {
535 [NETNSA_NONE] = { .type = NLA_UNSPEC },
536 [NETNSA_NSID] = { .type = NLA_S32 },
537 [NETNSA_PID] = { .type = NLA_U32 },
538 [NETNSA_FD] = { .type = NLA_U32 },
539};
540
541static int rtnl_net_newid(struct sk_buff *skb, struct nlmsghdr *nlh)
542{
543 struct net *net = sock_net(skb->sk);
544 struct nlattr *tb[NETNSA_MAX + 1];
545 unsigned long flags;
546 struct net *peer;
547 int nsid, err;
548
549 err = nlmsg_parse(nlh, sizeof(struct rtgenmsg), tb, NETNSA_MAX,
550 rtnl_net_policy);
551 if (err < 0)
552 return err;
553 if (!tb[NETNSA_NSID])
554 return -EINVAL;
555 nsid = nla_get_s32(tb[NETNSA_NSID]);
556
557 if (tb[NETNSA_PID])
558 peer = get_net_ns_by_pid(nla_get_u32(tb[NETNSA_PID]));
559 else if (tb[NETNSA_FD])
560 peer = get_net_ns_by_fd(nla_get_u32(tb[NETNSA_FD]));
561 else
562 return -EINVAL;
563 if (IS_ERR(peer))
564 return PTR_ERR(peer);
565
566 spin_lock_irqsave(&net->nsid_lock, flags);
567 if (__peernet2id(net, peer) >= 0) {
568 spin_unlock_irqrestore(&net->nsid_lock, flags);
569 err = -EEXIST;
570 goto out;
571 }
572
573 err = alloc_netid(net, peer, nsid);
574 spin_unlock_irqrestore(&net->nsid_lock, flags);
575 if (err >= 0) {
576 rtnl_net_notifyid(net, RTM_NEWNSID, err);
577 err = 0;
578 }
579out:
580 put_net(peer);
581 return err;
582}
583
584static int rtnl_net_get_size(void)
585{
586 return NLMSG_ALIGN(sizeof(struct rtgenmsg))
587 + nla_total_size(sizeof(s32)) /* NETNSA_NSID */
588 ;
589}
590
591static int rtnl_net_fill(struct sk_buff *skb, u32 portid, u32 seq, int flags,
592 int cmd, struct net *net, int nsid)
593{
594 struct nlmsghdr *nlh;
595 struct rtgenmsg *rth;
596
597 nlh = nlmsg_put(skb, portid, seq, cmd, sizeof(*rth), flags);
598 if (!nlh)
599 return -EMSGSIZE;
600
601 rth = nlmsg_data(nlh);
602 rth->rtgen_family = AF_UNSPEC;
603
604 if (nla_put_s32(skb, NETNSA_NSID, nsid))
605 goto nla_put_failure;
606
607 nlmsg_end(skb, nlh);
608 return 0;
609
610nla_put_failure:
611 nlmsg_cancel(skb, nlh);
612 return -EMSGSIZE;
613}
614
615static int rtnl_net_getid(struct sk_buff *skb, struct nlmsghdr *nlh)
616{
617 struct net *net = sock_net(skb->sk);
618 struct nlattr *tb[NETNSA_MAX + 1];
619 struct sk_buff *msg;
620 struct net *peer;
621 int err, id;
622
623 err = nlmsg_parse(nlh, sizeof(struct rtgenmsg), tb, NETNSA_MAX,
624 rtnl_net_policy);
625 if (err < 0)
626 return err;
627 if (tb[NETNSA_PID])
628 peer = get_net_ns_by_pid(nla_get_u32(tb[NETNSA_PID]));
629 else if (tb[NETNSA_FD])
630 peer = get_net_ns_by_fd(nla_get_u32(tb[NETNSA_FD]));
631 else
632 return -EINVAL;
633
634 if (IS_ERR(peer))
635 return PTR_ERR(peer);
636
637 msg = nlmsg_new(rtnl_net_get_size(), GFP_KERNEL);
638 if (!msg) {
639 err = -ENOMEM;
640 goto out;
641 }
642
643 id = peernet2id(net, peer);
644 err = rtnl_net_fill(msg, NETLINK_CB(skb).portid, nlh->nlmsg_seq, 0,
645 RTM_NEWNSID, net, id);
646 if (err < 0)
647 goto err_out;
648
649 err = rtnl_unicast(msg, net, NETLINK_CB(skb).portid);
650 goto out;
651
652err_out:
653 nlmsg_free(msg);
654out:
655 put_net(peer);
656 return err;
657}
658
659struct rtnl_net_dump_cb {
660 struct net *net;
661 struct sk_buff *skb;
662 struct netlink_callback *cb;
663 int idx;
664 int s_idx;
665};
666
667static int rtnl_net_dumpid_one(int id, void *peer, void *data)
668{
669 struct rtnl_net_dump_cb *net_cb = (struct rtnl_net_dump_cb *)data;
670 int ret;
671
672 if (net_cb->idx < net_cb->s_idx)
673 goto cont;
674
675 ret = rtnl_net_fill(net_cb->skb, NETLINK_CB(net_cb->cb->skb).portid,
676 net_cb->cb->nlh->nlmsg_seq, NLM_F_MULTI,
677 RTM_NEWNSID, net_cb->net, id);
678 if (ret < 0)
679 return ret;
680
681cont:
682 net_cb->idx++;
683 return 0;
684}
685
686static int rtnl_net_dumpid(struct sk_buff *skb, struct netlink_callback *cb)
687{
688 struct net *net = sock_net(skb->sk);
689 struct rtnl_net_dump_cb net_cb = {
690 .net = net,
691 .skb = skb,
692 .cb = cb,
693 .idx = 0,
694 .s_idx = cb->args[0],
695 };
696 unsigned long flags;
697
698 spin_lock_irqsave(&net->nsid_lock, flags);
699 idr_for_each(&net->netns_ids, rtnl_net_dumpid_one, &net_cb);
700 spin_unlock_irqrestore(&net->nsid_lock, flags);
701
702 cb->args[0] = net_cb.idx;
703 return skb->len;
704}
705
706static void rtnl_net_notifyid(struct net *net, int cmd, int id)
707{
708 struct sk_buff *msg;
709 int err = -ENOMEM;
710
711 msg = nlmsg_new(rtnl_net_get_size(), GFP_KERNEL);
712 if (!msg)
713 goto out;
714
715 err = rtnl_net_fill(msg, 0, 0, 0, cmd, net, id);
716 if (err < 0)
717 goto err_out;
718
719 rtnl_notify(msg, net, 0, RTNLGRP_NSID, NULL, 0);
720 return;
721
722err_out:
723 nlmsg_free(msg);
724out:
725 rtnl_set_sk_err(net, RTNLGRP_NSID, err);
726}
727
728static int __init net_ns_init(void)
729{
730 struct net_generic *ng;
731
732#ifdef CONFIG_NET_NS
733 net_cachep = kmem_cache_create("net_namespace", sizeof(struct net),
734 SMP_CACHE_BYTES,
735 SLAB_PANIC, NULL);
736
737 /* Create workqueue for cleanup */
738 netns_wq = create_singlethread_workqueue("netns");
739 if (!netns_wq)
740 panic("Could not create netns workq");
741#endif
742
743 ng = net_alloc_generic();
744 if (!ng)
745 panic("Could not allocate generic netns");
746
747 rcu_assign_pointer(init_net.gen, ng);
748
749 mutex_lock(&net_mutex);
750 if (setup_net(&init_net, &init_user_ns))
751 panic("Could not setup the initial network namespace");
752
753 rtnl_lock();
754 list_add_tail_rcu(&init_net.list, &net_namespace_list);
755 rtnl_unlock();
756
757 mutex_unlock(&net_mutex);
758
759 register_pernet_subsys(&net_ns_ops);
760
761 rtnl_register(PF_UNSPEC, RTM_NEWNSID, rtnl_net_newid, NULL, NULL);
762 rtnl_register(PF_UNSPEC, RTM_GETNSID, rtnl_net_getid, rtnl_net_dumpid,
763 NULL);
764
765 return 0;
766}
767
768pure_initcall(net_ns_init);
769
770#ifdef CONFIG_NET_NS
771static int __register_pernet_operations(struct list_head *list,
772 struct pernet_operations *ops)
773{
774 struct net *net;
775 int error;
776 LIST_HEAD(net_exit_list);
777
778 list_add_tail(&ops->list, list);
779 if (ops->init || (ops->id && ops->size)) {
780 for_each_net(net) {
781 error = ops_init(ops, net);
782 if (error)
783 goto out_undo;
784 list_add_tail(&net->exit_list, &net_exit_list);
785 }
786 }
787 return 0;
788
789out_undo:
790 /* If I have an error cleanup all namespaces I initialized */
791 list_del(&ops->list);
792 ops_exit_list(ops, &net_exit_list);
793 ops_free_list(ops, &net_exit_list);
794 return error;
795}
796
797static void __unregister_pernet_operations(struct pernet_operations *ops)
798{
799 struct net *net;
800 LIST_HEAD(net_exit_list);
801
802 list_del(&ops->list);
803 for_each_net(net)
804 list_add_tail(&net->exit_list, &net_exit_list);
805 ops_exit_list(ops, &net_exit_list);
806 ops_free_list(ops, &net_exit_list);
807}
808
809#else
810
811static int __register_pernet_operations(struct list_head *list,
812 struct pernet_operations *ops)
813{
814 return ops_init(ops, &init_net);
815}
816
817static void __unregister_pernet_operations(struct pernet_operations *ops)
818{
819 LIST_HEAD(net_exit_list);
820 list_add(&init_net.exit_list, &net_exit_list);
821 ops_exit_list(ops, &net_exit_list);
822 ops_free_list(ops, &net_exit_list);
823}
824
825#endif /* CONFIG_NET_NS */
826
827static DEFINE_IDA(net_generic_ids);
828
829static int register_pernet_operations(struct list_head *list,
830 struct pernet_operations *ops)
831{
832 int error;
833
834 if (ops->id) {
835again:
836 error = ida_get_new_above(&net_generic_ids, 1, ops->id);
837 if (error < 0) {
838 if (error == -EAGAIN) {
839 ida_pre_get(&net_generic_ids, GFP_KERNEL);
840 goto again;
841 }
842 return error;
843 }
844 max_gen_ptrs = max_t(unsigned int, max_gen_ptrs, *ops->id);
845 }
846 error = __register_pernet_operations(list, ops);
847 if (error) {
848 rcu_barrier();
849 if (ops->id)
850 ida_remove(&net_generic_ids, *ops->id);
851 }
852
853 return error;
854}
855
856static void unregister_pernet_operations(struct pernet_operations *ops)
857{
858
859 __unregister_pernet_operations(ops);
860 rcu_barrier();
861 if (ops->id)
862 ida_remove(&net_generic_ids, *ops->id);
863}
864
865/**
866 * register_pernet_subsys - register a network namespace subsystem
867 * @ops: pernet operations structure for the subsystem
868 *
869 * Register a subsystem which has init and exit functions
870 * that are called when network namespaces are created and
871 * destroyed respectively.
872 *
873 * When registered all network namespace init functions are
874 * called for every existing network namespace. Allowing kernel
875 * modules to have a race free view of the set of network namespaces.
876 *
877 * When a new network namespace is created all of the init
878 * methods are called in the order in which they were registered.
879 *
880 * When a network namespace is destroyed all of the exit methods
881 * are called in the reverse of the order with which they were
882 * registered.
883 */
884int register_pernet_subsys(struct pernet_operations *ops)
885{
886 int error;
887 mutex_lock(&net_mutex);
888 error = register_pernet_operations(first_device, ops);
889 mutex_unlock(&net_mutex);
890 return error;
891}
892EXPORT_SYMBOL_GPL(register_pernet_subsys);
893
894/**
895 * unregister_pernet_subsys - unregister a network namespace subsystem
896 * @ops: pernet operations structure to manipulate
897 *
898 * Remove the pernet operations structure from the list to be
899 * used when network namespaces are created or destroyed. In
900 * addition run the exit method for all existing network
901 * namespaces.
902 */
903void unregister_pernet_subsys(struct pernet_operations *ops)
904{
905 mutex_lock(&net_mutex);
906 unregister_pernet_operations(ops);
907 mutex_unlock(&net_mutex);
908}
909EXPORT_SYMBOL_GPL(unregister_pernet_subsys);
910
911/**
912 * register_pernet_device - register a network namespace device
913 * @ops: pernet operations structure for the subsystem
914 *
915 * Register a device which has init and exit functions
916 * that are called when network namespaces are created and
917 * destroyed respectively.
918 *
919 * When registered all network namespace init functions are
920 * called for every existing network namespace. Allowing kernel
921 * modules to have a race free view of the set of network namespaces.
922 *
923 * When a new network namespace is created all of the init
924 * methods are called in the order in which they were registered.
925 *
926 * When a network namespace is destroyed all of the exit methods
927 * are called in the reverse of the order with which they were
928 * registered.
929 */
930int register_pernet_device(struct pernet_operations *ops)
931{
932 int error;
933 mutex_lock(&net_mutex);
934 error = register_pernet_operations(&pernet_list, ops);
935 if (!error && (first_device == &pernet_list))
936 first_device = &ops->list;
937 mutex_unlock(&net_mutex);
938 return error;
939}
940EXPORT_SYMBOL_GPL(register_pernet_device);
941
942/**
943 * unregister_pernet_device - unregister a network namespace netdevice
944 * @ops: pernet operations structure to manipulate
945 *
946 * Remove the pernet operations structure from the list to be
947 * used when network namespaces are created or destroyed. In
948 * addition run the exit method for all existing network
949 * namespaces.
950 */
951void unregister_pernet_device(struct pernet_operations *ops)
952{
953 mutex_lock(&net_mutex);
954 if (&ops->list == first_device)
955 first_device = first_device->next;
956 unregister_pernet_operations(ops);
957 mutex_unlock(&net_mutex);
958}
959EXPORT_SYMBOL_GPL(unregister_pernet_device);
960
961#ifdef CONFIG_NET_NS
962static struct ns_common *netns_get(struct task_struct *task)
963{
964 struct net *net = NULL;
965 struct nsproxy *nsproxy;
966
967 task_lock(task);
968 nsproxy = task->nsproxy;
969 if (nsproxy)
970 net = get_net(nsproxy->net_ns);
971 task_unlock(task);
972
973 return net ? &net->ns : NULL;
974}
975
976static inline struct net *to_net_ns(struct ns_common *ns)
977{
978 return container_of(ns, struct net, ns);
979}
980
981static void netns_put(struct ns_common *ns)
982{
983 put_net(to_net_ns(ns));
984}
985
986static int netns_install(struct nsproxy *nsproxy, struct ns_common *ns)
987{
988 struct net *net = to_net_ns(ns);
989
990 if (!ns_capable(net->user_ns, CAP_SYS_ADMIN) ||
991 !ns_capable(current_user_ns(), CAP_SYS_ADMIN))
992 return -EPERM;
993
994 put_net(nsproxy->net_ns);
995 nsproxy->net_ns = get_net(net);
996 return 0;
997}
998
999const struct proc_ns_operations netns_operations = {
1000 .name = "net",
1001 .type = CLONE_NEWNET,
1002 .get = netns_get,
1003 .put = netns_put,
1004 .install = netns_install,
1005};
1006#endif
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/proc_fs.h>
14#include <linux/file.h>
15#include <linux/export.h>
16#include <net/net_namespace.h>
17#include <net/netns/generic.h>
18
19/*
20 * Our network namespace constructor/destructor lists
21 */
22
23static LIST_HEAD(pernet_list);
24static struct list_head *first_device = &pernet_list;
25static DEFINE_MUTEX(net_mutex);
26
27LIST_HEAD(net_namespace_list);
28EXPORT_SYMBOL_GPL(net_namespace_list);
29
30struct net init_net = {
31 .dev_base_head = LIST_HEAD_INIT(init_net.dev_base_head),
32};
33EXPORT_SYMBOL(init_net);
34
35#define INITIAL_NET_GEN_PTRS 13 /* +1 for len +2 for rcu_head */
36
37static unsigned int max_gen_ptrs = INITIAL_NET_GEN_PTRS;
38
39static struct net_generic *net_alloc_generic(void)
40{
41 struct net_generic *ng;
42 size_t generic_size = offsetof(struct net_generic, ptr[max_gen_ptrs]);
43
44 ng = kzalloc(generic_size, GFP_KERNEL);
45 if (ng)
46 ng->len = max_gen_ptrs;
47
48 return ng;
49}
50
51static int net_assign_generic(struct net *net, int id, void *data)
52{
53 struct net_generic *ng, *old_ng;
54
55 BUG_ON(!mutex_is_locked(&net_mutex));
56 BUG_ON(id == 0);
57
58 old_ng = rcu_dereference_protected(net->gen,
59 lockdep_is_held(&net_mutex));
60 ng = old_ng;
61 if (old_ng->len >= id)
62 goto assign;
63
64 ng = net_alloc_generic();
65 if (ng == NULL)
66 return -ENOMEM;
67
68 /*
69 * Some synchronisation notes:
70 *
71 * The net_generic explores the net->gen array inside rcu
72 * read section. Besides once set the net->gen->ptr[x]
73 * pointer never changes (see rules in netns/generic.h).
74 *
75 * That said, we simply duplicate this array and schedule
76 * the old copy for kfree after a grace period.
77 */
78
79 memcpy(&ng->ptr, &old_ng->ptr, old_ng->len * sizeof(void*));
80
81 rcu_assign_pointer(net->gen, ng);
82 kfree_rcu(old_ng, rcu);
83assign:
84 ng->ptr[id - 1] = data;
85 return 0;
86}
87
88static int ops_init(const struct pernet_operations *ops, struct net *net)
89{
90 int err = -ENOMEM;
91 void *data = NULL;
92
93 if (ops->id && ops->size) {
94 data = kzalloc(ops->size, GFP_KERNEL);
95 if (!data)
96 goto out;
97
98 err = net_assign_generic(net, *ops->id, data);
99 if (err)
100 goto cleanup;
101 }
102 err = 0;
103 if (ops->init)
104 err = ops->init(net);
105 if (!err)
106 return 0;
107
108cleanup:
109 kfree(data);
110
111out:
112 return err;
113}
114
115static void ops_free(const struct pernet_operations *ops, struct net *net)
116{
117 if (ops->id && ops->size) {
118 int id = *ops->id;
119 kfree(net_generic(net, id));
120 }
121}
122
123static void ops_exit_list(const struct pernet_operations *ops,
124 struct list_head *net_exit_list)
125{
126 struct net *net;
127 if (ops->exit) {
128 list_for_each_entry(net, net_exit_list, exit_list)
129 ops->exit(net);
130 }
131 if (ops->exit_batch)
132 ops->exit_batch(net_exit_list);
133}
134
135static void ops_free_list(const struct pernet_operations *ops,
136 struct list_head *net_exit_list)
137{
138 struct net *net;
139 if (ops->size && ops->id) {
140 list_for_each_entry(net, net_exit_list, exit_list)
141 ops_free(ops, net);
142 }
143}
144
145/*
146 * setup_net runs the initializers for the network namespace object.
147 */
148static __net_init int setup_net(struct net *net)
149{
150 /* Must be called with net_mutex held */
151 const struct pernet_operations *ops, *saved_ops;
152 int error = 0;
153 LIST_HEAD(net_exit_list);
154
155 atomic_set(&net->count, 1);
156 atomic_set(&net->passive, 1);
157 net->dev_base_seq = 1;
158
159#ifdef NETNS_REFCNT_DEBUG
160 atomic_set(&net->use_count, 0);
161#endif
162
163 list_for_each_entry(ops, &pernet_list, list) {
164 error = ops_init(ops, net);
165 if (error < 0)
166 goto out_undo;
167 }
168out:
169 return error;
170
171out_undo:
172 /* Walk through the list backwards calling the exit functions
173 * for the pernet modules whose init functions did not fail.
174 */
175 list_add(&net->exit_list, &net_exit_list);
176 saved_ops = ops;
177 list_for_each_entry_continue_reverse(ops, &pernet_list, list)
178 ops_exit_list(ops, &net_exit_list);
179
180 ops = saved_ops;
181 list_for_each_entry_continue_reverse(ops, &pernet_list, list)
182 ops_free_list(ops, &net_exit_list);
183
184 rcu_barrier();
185 goto out;
186}
187
188
189#ifdef CONFIG_NET_NS
190static struct kmem_cache *net_cachep;
191static struct workqueue_struct *netns_wq;
192
193static struct net *net_alloc(void)
194{
195 struct net *net = NULL;
196 struct net_generic *ng;
197
198 ng = net_alloc_generic();
199 if (!ng)
200 goto out;
201
202 net = kmem_cache_zalloc(net_cachep, GFP_KERNEL);
203 if (!net)
204 goto out_free;
205
206 rcu_assign_pointer(net->gen, ng);
207out:
208 return net;
209
210out_free:
211 kfree(ng);
212 goto out;
213}
214
215static void net_free(struct net *net)
216{
217#ifdef NETNS_REFCNT_DEBUG
218 if (unlikely(atomic_read(&net->use_count) != 0)) {
219 pr_emerg("network namespace not free! Usage: %d\n",
220 atomic_read(&net->use_count));
221 return;
222 }
223#endif
224 kfree(net->gen);
225 kmem_cache_free(net_cachep, net);
226}
227
228void net_drop_ns(void *p)
229{
230 struct net *ns = p;
231 if (ns && atomic_dec_and_test(&ns->passive))
232 net_free(ns);
233}
234
235struct net *copy_net_ns(unsigned long flags, struct net *old_net)
236{
237 struct net *net;
238 int rv;
239
240 if (!(flags & CLONE_NEWNET))
241 return get_net(old_net);
242
243 net = net_alloc();
244 if (!net)
245 return ERR_PTR(-ENOMEM);
246 mutex_lock(&net_mutex);
247 rv = setup_net(net);
248 if (rv == 0) {
249 rtnl_lock();
250 list_add_tail_rcu(&net->list, &net_namespace_list);
251 rtnl_unlock();
252 }
253 mutex_unlock(&net_mutex);
254 if (rv < 0) {
255 net_drop_ns(net);
256 return ERR_PTR(rv);
257 }
258 return net;
259}
260
261static DEFINE_SPINLOCK(cleanup_list_lock);
262static LIST_HEAD(cleanup_list); /* Must hold cleanup_list_lock to touch */
263
264static void cleanup_net(struct work_struct *work)
265{
266 const struct pernet_operations *ops;
267 struct net *net, *tmp;
268 LIST_HEAD(net_kill_list);
269 LIST_HEAD(net_exit_list);
270
271 /* Atomically snapshot the list of namespaces to cleanup */
272 spin_lock_irq(&cleanup_list_lock);
273 list_replace_init(&cleanup_list, &net_kill_list);
274 spin_unlock_irq(&cleanup_list_lock);
275
276 mutex_lock(&net_mutex);
277
278 /* Don't let anyone else find us. */
279 rtnl_lock();
280 list_for_each_entry(net, &net_kill_list, cleanup_list) {
281 list_del_rcu(&net->list);
282 list_add_tail(&net->exit_list, &net_exit_list);
283 }
284 rtnl_unlock();
285
286 /*
287 * Another CPU might be rcu-iterating the list, wait for it.
288 * This needs to be before calling the exit() notifiers, so
289 * the rcu_barrier() below isn't sufficient alone.
290 */
291 synchronize_rcu();
292
293 /* Run all of the network namespace exit methods */
294 list_for_each_entry_reverse(ops, &pernet_list, list)
295 ops_exit_list(ops, &net_exit_list);
296
297 /* Free the net generic variables */
298 list_for_each_entry_reverse(ops, &pernet_list, list)
299 ops_free_list(ops, &net_exit_list);
300
301 mutex_unlock(&net_mutex);
302
303 /* Ensure there are no outstanding rcu callbacks using this
304 * network namespace.
305 */
306 rcu_barrier();
307
308 /* Finally it is safe to free my network namespace structure */
309 list_for_each_entry_safe(net, tmp, &net_exit_list, exit_list) {
310 list_del_init(&net->exit_list);
311 net_drop_ns(net);
312 }
313}
314static DECLARE_WORK(net_cleanup_work, cleanup_net);
315
316void __put_net(struct net *net)
317{
318 /* Cleanup the network namespace in process context */
319 unsigned long flags;
320
321 spin_lock_irqsave(&cleanup_list_lock, flags);
322 list_add(&net->cleanup_list, &cleanup_list);
323 spin_unlock_irqrestore(&cleanup_list_lock, flags);
324
325 queue_work(netns_wq, &net_cleanup_work);
326}
327EXPORT_SYMBOL_GPL(__put_net);
328
329struct net *get_net_ns_by_fd(int fd)
330{
331 struct proc_inode *ei;
332 struct file *file;
333 struct net *net;
334
335 file = proc_ns_fget(fd);
336 if (IS_ERR(file))
337 return ERR_CAST(file);
338
339 ei = PROC_I(file->f_dentry->d_inode);
340 if (ei->ns_ops == &netns_operations)
341 net = get_net(ei->ns);
342 else
343 net = ERR_PTR(-EINVAL);
344
345 fput(file);
346 return net;
347}
348
349#else
350struct net *copy_net_ns(unsigned long flags, struct net *old_net)
351{
352 if (flags & CLONE_NEWNET)
353 return ERR_PTR(-EINVAL);
354 return old_net;
355}
356
357struct net *get_net_ns_by_fd(int fd)
358{
359 return ERR_PTR(-EINVAL);
360}
361#endif
362
363struct net *get_net_ns_by_pid(pid_t pid)
364{
365 struct task_struct *tsk;
366 struct net *net;
367
368 /* Lookup the network namespace */
369 net = ERR_PTR(-ESRCH);
370 rcu_read_lock();
371 tsk = find_task_by_vpid(pid);
372 if (tsk) {
373 struct nsproxy *nsproxy;
374 nsproxy = task_nsproxy(tsk);
375 if (nsproxy)
376 net = get_net(nsproxy->net_ns);
377 }
378 rcu_read_unlock();
379 return net;
380}
381EXPORT_SYMBOL_GPL(get_net_ns_by_pid);
382
383static int __init net_ns_init(void)
384{
385 struct net_generic *ng;
386
387#ifdef CONFIG_NET_NS
388 net_cachep = kmem_cache_create("net_namespace", sizeof(struct net),
389 SMP_CACHE_BYTES,
390 SLAB_PANIC, NULL);
391
392 /* Create workqueue for cleanup */
393 netns_wq = create_singlethread_workqueue("netns");
394 if (!netns_wq)
395 panic("Could not create netns workq");
396#endif
397
398 ng = net_alloc_generic();
399 if (!ng)
400 panic("Could not allocate generic netns");
401
402 rcu_assign_pointer(init_net.gen, ng);
403
404 mutex_lock(&net_mutex);
405 if (setup_net(&init_net))
406 panic("Could not setup the initial network namespace");
407
408 rtnl_lock();
409 list_add_tail_rcu(&init_net.list, &net_namespace_list);
410 rtnl_unlock();
411
412 mutex_unlock(&net_mutex);
413
414 return 0;
415}
416
417pure_initcall(net_ns_init);
418
419#ifdef CONFIG_NET_NS
420static int __register_pernet_operations(struct list_head *list,
421 struct pernet_operations *ops)
422{
423 struct net *net;
424 int error;
425 LIST_HEAD(net_exit_list);
426
427 list_add_tail(&ops->list, list);
428 if (ops->init || (ops->id && ops->size)) {
429 for_each_net(net) {
430 error = ops_init(ops, net);
431 if (error)
432 goto out_undo;
433 list_add_tail(&net->exit_list, &net_exit_list);
434 }
435 }
436 return 0;
437
438out_undo:
439 /* If I have an error cleanup all namespaces I initialized */
440 list_del(&ops->list);
441 ops_exit_list(ops, &net_exit_list);
442 ops_free_list(ops, &net_exit_list);
443 return error;
444}
445
446static void __unregister_pernet_operations(struct pernet_operations *ops)
447{
448 struct net *net;
449 LIST_HEAD(net_exit_list);
450
451 list_del(&ops->list);
452 for_each_net(net)
453 list_add_tail(&net->exit_list, &net_exit_list);
454 ops_exit_list(ops, &net_exit_list);
455 ops_free_list(ops, &net_exit_list);
456}
457
458#else
459
460static int __register_pernet_operations(struct list_head *list,
461 struct pernet_operations *ops)
462{
463 return ops_init(ops, &init_net);
464}
465
466static void __unregister_pernet_operations(struct pernet_operations *ops)
467{
468 LIST_HEAD(net_exit_list);
469 list_add(&init_net.exit_list, &net_exit_list);
470 ops_exit_list(ops, &net_exit_list);
471 ops_free_list(ops, &net_exit_list);
472}
473
474#endif /* CONFIG_NET_NS */
475
476static DEFINE_IDA(net_generic_ids);
477
478static int register_pernet_operations(struct list_head *list,
479 struct pernet_operations *ops)
480{
481 int error;
482
483 if (ops->id) {
484again:
485 error = ida_get_new_above(&net_generic_ids, 1, ops->id);
486 if (error < 0) {
487 if (error == -EAGAIN) {
488 ida_pre_get(&net_generic_ids, GFP_KERNEL);
489 goto again;
490 }
491 return error;
492 }
493 max_gen_ptrs = max_t(unsigned int, max_gen_ptrs, *ops->id);
494 }
495 error = __register_pernet_operations(list, ops);
496 if (error) {
497 rcu_barrier();
498 if (ops->id)
499 ida_remove(&net_generic_ids, *ops->id);
500 }
501
502 return error;
503}
504
505static void unregister_pernet_operations(struct pernet_operations *ops)
506{
507
508 __unregister_pernet_operations(ops);
509 rcu_barrier();
510 if (ops->id)
511 ida_remove(&net_generic_ids, *ops->id);
512}
513
514/**
515 * register_pernet_subsys - register a network namespace subsystem
516 * @ops: pernet operations structure for the subsystem
517 *
518 * Register a subsystem which has init and exit functions
519 * that are called when network namespaces are created and
520 * destroyed respectively.
521 *
522 * When registered all network namespace init functions are
523 * called for every existing network namespace. Allowing kernel
524 * modules to have a race free view of the set of network namespaces.
525 *
526 * When a new network namespace is created all of the init
527 * methods are called in the order in which they were registered.
528 *
529 * When a network namespace is destroyed all of the exit methods
530 * are called in the reverse of the order with which they were
531 * registered.
532 */
533int register_pernet_subsys(struct pernet_operations *ops)
534{
535 int error;
536 mutex_lock(&net_mutex);
537 error = register_pernet_operations(first_device, ops);
538 mutex_unlock(&net_mutex);
539 return error;
540}
541EXPORT_SYMBOL_GPL(register_pernet_subsys);
542
543/**
544 * unregister_pernet_subsys - unregister a network namespace subsystem
545 * @ops: pernet operations structure to manipulate
546 *
547 * Remove the pernet operations structure from the list to be
548 * used when network namespaces are created or destroyed. In
549 * addition run the exit method for all existing network
550 * namespaces.
551 */
552void unregister_pernet_subsys(struct pernet_operations *ops)
553{
554 mutex_lock(&net_mutex);
555 unregister_pernet_operations(ops);
556 mutex_unlock(&net_mutex);
557}
558EXPORT_SYMBOL_GPL(unregister_pernet_subsys);
559
560/**
561 * register_pernet_device - register a network namespace device
562 * @ops: pernet operations structure for the subsystem
563 *
564 * Register a device which has init and exit functions
565 * that are called when network namespaces are created and
566 * destroyed respectively.
567 *
568 * When registered all network namespace init functions are
569 * called for every existing network namespace. Allowing kernel
570 * modules to have a race free view of the set of network namespaces.
571 *
572 * When a new network namespace is created all of the init
573 * methods are called in the order in which they were registered.
574 *
575 * When a network namespace is destroyed all of the exit methods
576 * are called in the reverse of the order with which they were
577 * registered.
578 */
579int register_pernet_device(struct pernet_operations *ops)
580{
581 int error;
582 mutex_lock(&net_mutex);
583 error = register_pernet_operations(&pernet_list, ops);
584 if (!error && (first_device == &pernet_list))
585 first_device = &ops->list;
586 mutex_unlock(&net_mutex);
587 return error;
588}
589EXPORT_SYMBOL_GPL(register_pernet_device);
590
591/**
592 * unregister_pernet_device - unregister a network namespace netdevice
593 * @ops: pernet operations structure to manipulate
594 *
595 * Remove the pernet operations structure from the list to be
596 * used when network namespaces are created or destroyed. In
597 * addition run the exit method for all existing network
598 * namespaces.
599 */
600void unregister_pernet_device(struct pernet_operations *ops)
601{
602 mutex_lock(&net_mutex);
603 if (&ops->list == first_device)
604 first_device = first_device->next;
605 unregister_pernet_operations(ops);
606 mutex_unlock(&net_mutex);
607}
608EXPORT_SYMBOL_GPL(unregister_pernet_device);
609
610#ifdef CONFIG_NET_NS
611static void *netns_get(struct task_struct *task)
612{
613 struct net *net = NULL;
614 struct nsproxy *nsproxy;
615
616 rcu_read_lock();
617 nsproxy = task_nsproxy(task);
618 if (nsproxy)
619 net = get_net(nsproxy->net_ns);
620 rcu_read_unlock();
621
622 return net;
623}
624
625static void netns_put(void *ns)
626{
627 put_net(ns);
628}
629
630static int netns_install(struct nsproxy *nsproxy, void *ns)
631{
632 put_net(nsproxy->net_ns);
633 nsproxy->net_ns = get_net(ns);
634 return 0;
635}
636
637const struct proc_ns_operations netns_operations = {
638 .name = "net",
639 .type = CLONE_NEWNET,
640 .get = netns_get,
641 .put = netns_put,
642 .install = netns_install,
643};
644#endif