1 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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>
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 <linux/sched/task.h>
22 #include <net/netlink.h>
23 #include <net/net_namespace.h>
24 #include <net/netns/generic.h>
27 * Our network namespace constructor/destructor lists
30 static LIST_HEAD(pernet_list);
31 static struct list_head *first_device = &pernet_list;
32 DEFINE_MUTEX(net_mutex);
34 LIST_HEAD(net_namespace_list);
35 EXPORT_SYMBOL_GPL(net_namespace_list);
37 struct net init_net = {
38 .count = ATOMIC_INIT(1),
39 .dev_base_head = LIST_HEAD_INIT(init_net.dev_base_head),
41 EXPORT_SYMBOL(init_net);
43 static bool init_net_initialized;
45 #define MIN_PERNET_OPS_ID \
46 ((sizeof(struct net_generic) + sizeof(void *) - 1) / sizeof(void *))
48 #define INITIAL_NET_GEN_PTRS 13 /* +1 for len +2 for rcu_head */
50 static unsigned int max_gen_ptrs = INITIAL_NET_GEN_PTRS;
52 static struct net_generic *net_alloc_generic(void)
54 struct net_generic *ng;
55 unsigned int generic_size = offsetof(struct net_generic, ptr[max_gen_ptrs]);
57 ng = kzalloc(generic_size, GFP_KERNEL);
59 ng->s.len = max_gen_ptrs;
64 static int net_assign_generic(struct net *net, unsigned int id, void *data)
66 struct net_generic *ng, *old_ng;
68 BUG_ON(!mutex_is_locked(&net_mutex));
69 BUG_ON(id < MIN_PERNET_OPS_ID);
71 old_ng = rcu_dereference_protected(net->gen,
72 lockdep_is_held(&net_mutex));
73 if (old_ng->s.len > id) {
74 old_ng->ptr[id] = data;
78 ng = net_alloc_generic();
83 * Some synchronisation notes:
85 * The net_generic explores the net->gen array inside rcu
86 * read section. Besides once set the net->gen->ptr[x]
87 * pointer never changes (see rules in netns/generic.h).
89 * That said, we simply duplicate this array and schedule
90 * the old copy for kfree after a grace period.
93 memcpy(&ng->ptr[MIN_PERNET_OPS_ID], &old_ng->ptr[MIN_PERNET_OPS_ID],
94 (old_ng->s.len - MIN_PERNET_OPS_ID) * sizeof(void *));
97 rcu_assign_pointer(net->gen, ng);
98 kfree_rcu(old_ng, s.rcu);
102 static int ops_init(const struct pernet_operations *ops, struct net *net)
107 if (ops->id && ops->size) {
108 data = kzalloc(ops->size, GFP_KERNEL);
112 err = net_assign_generic(net, *ops->id, data);
118 err = ops->init(net);
129 static void ops_free(const struct pernet_operations *ops, struct net *net)
131 if (ops->id && ops->size) {
132 kfree(net_generic(net, *ops->id));
136 static void ops_exit_list(const struct pernet_operations *ops,
137 struct list_head *net_exit_list)
141 list_for_each_entry(net, net_exit_list, exit_list) {
147 ops->exit_batch(net_exit_list);
150 static void ops_free_list(const struct pernet_operations *ops,
151 struct list_head *net_exit_list)
154 if (ops->size && ops->id) {
155 list_for_each_entry(net, net_exit_list, exit_list)
160 /* should be called with nsid_lock held */
161 static int alloc_netid(struct net *net, struct net *peer, int reqid)
163 int min = 0, max = 0;
170 return idr_alloc(&net->netns_ids, peer, min, max, GFP_ATOMIC);
173 /* This function is used by idr_for_each(). If net is equal to peer, the
174 * function returns the id so that idr_for_each() stops. Because we cannot
175 * returns the id 0 (idr_for_each() will not stop), we return the magic value
176 * NET_ID_ZERO (-1) for it.
178 #define NET_ID_ZERO -1
179 static int net_eq_idr(int id, void *net, void *peer)
181 if (net_eq(net, peer))
182 return id ? : NET_ID_ZERO;
186 /* Must be called from RCU-critical section or with nsid_lock held. If
187 * a new id is assigned, the bool alloc is set to true, thus the
188 * caller knows that the new id must be notified via rtnl.
190 static int __peernet2id_alloc(struct net *net, struct net *peer, bool *alloc)
192 int id = idr_for_each(&net->netns_ids, net_eq_idr, peer);
193 bool alloc_it = *alloc;
197 /* Magic value for id 0. */
198 if (id == NET_ID_ZERO)
204 id = alloc_netid(net, peer, -1);
206 return id >= 0 ? id : NETNSA_NSID_NOT_ASSIGNED;
209 return NETNSA_NSID_NOT_ASSIGNED;
212 /* Must be called from RCU-critical section or with nsid_lock held */
213 static int __peernet2id(struct net *net, struct net *peer)
217 return __peernet2id_alloc(net, peer, &no);
220 static void rtnl_net_notifyid(struct net *net, int cmd, int id);
221 /* This function returns the id of a peer netns. If no id is assigned, one will
222 * be allocated and returned.
224 int peernet2id_alloc(struct net *net, struct net *peer)
229 if (atomic_read(&net->count) == 0)
230 return NETNSA_NSID_NOT_ASSIGNED;
231 spin_lock_bh(&net->nsid_lock);
232 alloc = atomic_read(&peer->count) == 0 ? false : true;
233 id = __peernet2id_alloc(net, peer, &alloc);
234 spin_unlock_bh(&net->nsid_lock);
235 if (alloc && id >= 0)
236 rtnl_net_notifyid(net, RTM_NEWNSID, id);
240 /* This function returns, if assigned, the id of a peer netns. */
241 int peernet2id(struct net *net, struct net *peer)
246 id = __peernet2id(net, peer);
251 EXPORT_SYMBOL(peernet2id);
253 /* This function returns true is the peer netns has an id assigned into the
256 bool peernet_has_id(struct net *net, struct net *peer)
258 return peernet2id(net, peer) >= 0;
261 struct net *get_net_ns_by_id(struct net *net, int id)
269 spin_lock_bh(&net->nsid_lock);
270 peer = idr_find(&net->netns_ids, id);
272 peer = maybe_get_net(peer);
273 spin_unlock_bh(&net->nsid_lock);
280 * setup_net runs the initializers for the network namespace object.
282 static __net_init int setup_net(struct net *net, struct user_namespace *user_ns)
284 /* Must be called with net_mutex held */
285 const struct pernet_operations *ops, *saved_ops;
287 LIST_HEAD(net_exit_list);
289 atomic_set(&net->count, 1);
290 refcount_set(&net->passive, 1);
291 get_random_bytes(&net->hash_mix, sizeof(u32));
292 net->dev_base_seq = 1;
293 net->user_ns = user_ns;
294 idr_init(&net->netns_ids);
295 spin_lock_init(&net->nsid_lock);
297 list_for_each_entry(ops, &pernet_list, list) {
298 error = ops_init(ops, net);
306 /* Walk through the list backwards calling the exit functions
307 * for the pernet modules whose init functions did not fail.
309 list_add(&net->exit_list, &net_exit_list);
311 list_for_each_entry_continue_reverse(ops, &pernet_list, list)
312 ops_exit_list(ops, &net_exit_list);
315 list_for_each_entry_continue_reverse(ops, &pernet_list, list)
316 ops_free_list(ops, &net_exit_list);
322 static int __net_init net_defaults_init_net(struct net *net)
324 net->core.sysctl_somaxconn = SOMAXCONN;
328 static struct pernet_operations net_defaults_ops = {
329 .init = net_defaults_init_net,
332 static __init int net_defaults_init(void)
334 if (register_pernet_subsys(&net_defaults_ops))
335 panic("Cannot initialize net default settings");
340 core_initcall(net_defaults_init);
343 static struct ucounts *inc_net_namespaces(struct user_namespace *ns)
345 return inc_ucount(ns, current_euid(), UCOUNT_NET_NAMESPACES);
348 static void dec_net_namespaces(struct ucounts *ucounts)
350 dec_ucount(ucounts, UCOUNT_NET_NAMESPACES);
353 static struct kmem_cache *net_cachep;
354 static struct workqueue_struct *netns_wq;
356 static struct net *net_alloc(void)
358 struct net *net = NULL;
359 struct net_generic *ng;
361 ng = net_alloc_generic();
365 net = kmem_cache_zalloc(net_cachep, GFP_KERNEL);
369 rcu_assign_pointer(net->gen, ng);
378 static void net_free(struct net *net)
380 kfree(rcu_access_pointer(net->gen));
381 kmem_cache_free(net_cachep, net);
384 void net_drop_ns(void *p)
387 if (ns && refcount_dec_and_test(&ns->passive))
391 struct net *copy_net_ns(unsigned long flags,
392 struct user_namespace *user_ns, struct net *old_net)
394 struct ucounts *ucounts;
398 if (!(flags & CLONE_NEWNET))
399 return get_net(old_net);
401 ucounts = inc_net_namespaces(user_ns);
403 return ERR_PTR(-ENOSPC);
407 dec_net_namespaces(ucounts);
408 return ERR_PTR(-ENOMEM);
411 get_user_ns(user_ns);
413 rv = mutex_lock_killable(&net_mutex);
416 dec_net_namespaces(ucounts);
417 put_user_ns(user_ns);
421 net->ucounts = ucounts;
422 rv = setup_net(net, user_ns);
425 list_add_tail_rcu(&net->list, &net_namespace_list);
428 mutex_unlock(&net_mutex);
430 dec_net_namespaces(ucounts);
431 put_user_ns(user_ns);
438 static DEFINE_SPINLOCK(cleanup_list_lock);
439 static LIST_HEAD(cleanup_list); /* Must hold cleanup_list_lock to touch */
441 static void cleanup_net(struct work_struct *work)
443 const struct pernet_operations *ops;
444 struct net *net, *tmp;
445 struct list_head net_kill_list;
446 LIST_HEAD(net_exit_list);
448 /* Atomically snapshot the list of namespaces to cleanup */
449 spin_lock_irq(&cleanup_list_lock);
450 list_replace_init(&cleanup_list, &net_kill_list);
451 spin_unlock_irq(&cleanup_list_lock);
453 mutex_lock(&net_mutex);
455 /* Don't let anyone else find us. */
457 list_for_each_entry(net, &net_kill_list, cleanup_list) {
458 list_del_rcu(&net->list);
459 list_add_tail(&net->exit_list, &net_exit_list);
463 spin_lock_bh(&tmp->nsid_lock);
464 id = __peernet2id(tmp, net);
466 idr_remove(&tmp->netns_ids, id);
467 spin_unlock_bh(&tmp->nsid_lock);
469 rtnl_net_notifyid(tmp, RTM_DELNSID, id);
471 spin_lock_bh(&net->nsid_lock);
472 idr_destroy(&net->netns_ids);
473 spin_unlock_bh(&net->nsid_lock);
479 * Another CPU might be rcu-iterating the list, wait for it.
480 * This needs to be before calling the exit() notifiers, so
481 * the rcu_barrier() below isn't sufficient alone.
485 /* Run all of the network namespace exit methods */
486 list_for_each_entry_reverse(ops, &pernet_list, list)
487 ops_exit_list(ops, &net_exit_list);
489 /* Free the net generic variables */
490 list_for_each_entry_reverse(ops, &pernet_list, list)
491 ops_free_list(ops, &net_exit_list);
493 mutex_unlock(&net_mutex);
495 /* Ensure there are no outstanding rcu callbacks using this
500 /* Finally it is safe to free my network namespace structure */
501 list_for_each_entry_safe(net, tmp, &net_exit_list, exit_list) {
502 list_del_init(&net->exit_list);
503 dec_net_namespaces(net->ucounts);
504 put_user_ns(net->user_ns);
510 * net_ns_barrier - wait until concurrent net_cleanup_work is done
512 * cleanup_net runs from work queue and will first remove namespaces
513 * from the global list, then run net exit functions.
515 * Call this in module exit path to make sure that all netns
516 * ->exit ops have been invoked before the function is removed.
518 void net_ns_barrier(void)
520 mutex_lock(&net_mutex);
521 mutex_unlock(&net_mutex);
523 EXPORT_SYMBOL(net_ns_barrier);
525 static DECLARE_WORK(net_cleanup_work, cleanup_net);
527 void __put_net(struct net *net)
529 /* Cleanup the network namespace in process context */
532 spin_lock_irqsave(&cleanup_list_lock, flags);
533 list_add(&net->cleanup_list, &cleanup_list);
534 spin_unlock_irqrestore(&cleanup_list_lock, flags);
536 queue_work(netns_wq, &net_cleanup_work);
538 EXPORT_SYMBOL_GPL(__put_net);
540 struct net *get_net_ns_by_fd(int fd)
543 struct ns_common *ns;
546 file = proc_ns_fget(fd);
548 return ERR_CAST(file);
550 ns = get_proc_ns(file_inode(file));
551 if (ns->ops == &netns_operations)
552 net = get_net(container_of(ns, struct net, ns));
554 net = ERR_PTR(-EINVAL);
561 struct net *get_net_ns_by_fd(int fd)
563 return ERR_PTR(-EINVAL);
566 EXPORT_SYMBOL_GPL(get_net_ns_by_fd);
568 struct net *get_net_ns_by_pid(pid_t pid)
570 struct task_struct *tsk;
573 /* Lookup the network namespace */
574 net = ERR_PTR(-ESRCH);
576 tsk = find_task_by_vpid(pid);
578 struct nsproxy *nsproxy;
580 nsproxy = tsk->nsproxy;
582 net = get_net(nsproxy->net_ns);
588 EXPORT_SYMBOL_GPL(get_net_ns_by_pid);
590 static __net_init int net_ns_net_init(struct net *net)
593 net->ns.ops = &netns_operations;
595 return ns_alloc_inum(&net->ns);
598 static __net_exit void net_ns_net_exit(struct net *net)
600 ns_free_inum(&net->ns);
603 static struct pernet_operations __net_initdata net_ns_ops = {
604 .init = net_ns_net_init,
605 .exit = net_ns_net_exit,
608 static const struct nla_policy rtnl_net_policy[NETNSA_MAX + 1] = {
609 [NETNSA_NONE] = { .type = NLA_UNSPEC },
610 [NETNSA_NSID] = { .type = NLA_S32 },
611 [NETNSA_PID] = { .type = NLA_U32 },
612 [NETNSA_FD] = { .type = NLA_U32 },
615 static int rtnl_net_newid(struct sk_buff *skb, struct nlmsghdr *nlh,
616 struct netlink_ext_ack *extack)
618 struct net *net = sock_net(skb->sk);
619 struct nlattr *tb[NETNSA_MAX + 1];
624 err = nlmsg_parse(nlh, sizeof(struct rtgenmsg), tb, NETNSA_MAX,
625 rtnl_net_policy, extack);
628 if (!tb[NETNSA_NSID]) {
629 NL_SET_ERR_MSG(extack, "nsid is missing");
632 nsid = nla_get_s32(tb[NETNSA_NSID]);
634 if (tb[NETNSA_PID]) {
635 peer = get_net_ns_by_pid(nla_get_u32(tb[NETNSA_PID]));
636 nla = tb[NETNSA_PID];
637 } else if (tb[NETNSA_FD]) {
638 peer = get_net_ns_by_fd(nla_get_u32(tb[NETNSA_FD]));
641 NL_SET_ERR_MSG(extack, "Peer netns reference is missing");
645 NL_SET_BAD_ATTR(extack, nla);
646 NL_SET_ERR_MSG(extack, "Peer netns reference is invalid");
647 return PTR_ERR(peer);
650 spin_lock_bh(&net->nsid_lock);
651 if (__peernet2id(net, peer) >= 0) {
652 spin_unlock_bh(&net->nsid_lock);
654 NL_SET_BAD_ATTR(extack, nla);
655 NL_SET_ERR_MSG(extack,
656 "Peer netns already has a nsid assigned");
660 err = alloc_netid(net, peer, nsid);
661 spin_unlock_bh(&net->nsid_lock);
663 rtnl_net_notifyid(net, RTM_NEWNSID, err);
665 } else if (err == -ENOSPC && nsid >= 0) {
667 NL_SET_BAD_ATTR(extack, tb[NETNSA_NSID]);
668 NL_SET_ERR_MSG(extack, "The specified nsid is already used");
675 static int rtnl_net_get_size(void)
677 return NLMSG_ALIGN(sizeof(struct rtgenmsg))
678 + nla_total_size(sizeof(s32)) /* NETNSA_NSID */
682 static int rtnl_net_fill(struct sk_buff *skb, u32 portid, u32 seq, int flags,
683 int cmd, struct net *net, int nsid)
685 struct nlmsghdr *nlh;
686 struct rtgenmsg *rth;
688 nlh = nlmsg_put(skb, portid, seq, cmd, sizeof(*rth), flags);
692 rth = nlmsg_data(nlh);
693 rth->rtgen_family = AF_UNSPEC;
695 if (nla_put_s32(skb, NETNSA_NSID, nsid))
696 goto nla_put_failure;
702 nlmsg_cancel(skb, nlh);
706 static int rtnl_net_getid(struct sk_buff *skb, struct nlmsghdr *nlh,
707 struct netlink_ext_ack *extack)
709 struct net *net = sock_net(skb->sk);
710 struct nlattr *tb[NETNSA_MAX + 1];
716 err = nlmsg_parse(nlh, sizeof(struct rtgenmsg), tb, NETNSA_MAX,
717 rtnl_net_policy, extack);
720 if (tb[NETNSA_PID]) {
721 peer = get_net_ns_by_pid(nla_get_u32(tb[NETNSA_PID]));
722 nla = tb[NETNSA_PID];
723 } else if (tb[NETNSA_FD]) {
724 peer = get_net_ns_by_fd(nla_get_u32(tb[NETNSA_FD]));
727 NL_SET_ERR_MSG(extack, "Peer netns reference is missing");
732 NL_SET_BAD_ATTR(extack, nla);
733 NL_SET_ERR_MSG(extack, "Peer netns reference is invalid");
734 return PTR_ERR(peer);
737 msg = nlmsg_new(rtnl_net_get_size(), GFP_KERNEL);
743 id = peernet2id(net, peer);
744 err = rtnl_net_fill(msg, NETLINK_CB(skb).portid, nlh->nlmsg_seq, 0,
745 RTM_NEWNSID, net, id);
749 err = rtnl_unicast(msg, net, NETLINK_CB(skb).portid);
759 struct rtnl_net_dump_cb {
762 struct netlink_callback *cb;
767 /* Runs in RCU-critical section. */
768 static int rtnl_net_dumpid_one(int id, void *peer, void *data)
770 struct rtnl_net_dump_cb *net_cb = (struct rtnl_net_dump_cb *)data;
773 if (net_cb->idx < net_cb->s_idx)
776 ret = rtnl_net_fill(net_cb->skb, NETLINK_CB(net_cb->cb->skb).portid,
777 net_cb->cb->nlh->nlmsg_seq, NLM_F_MULTI,
778 RTM_NEWNSID, net_cb->net, id);
787 static int rtnl_net_dumpid(struct sk_buff *skb, struct netlink_callback *cb)
789 struct net *net = sock_net(skb->sk);
790 struct rtnl_net_dump_cb net_cb = {
795 .s_idx = cb->args[0],
799 idr_for_each(&net->netns_ids, rtnl_net_dumpid_one, &net_cb);
802 cb->args[0] = net_cb.idx;
806 static void rtnl_net_notifyid(struct net *net, int cmd, int id)
811 msg = nlmsg_new(rtnl_net_get_size(), GFP_KERNEL);
815 err = rtnl_net_fill(msg, 0, 0, 0, cmd, net, id);
819 rtnl_notify(msg, net, 0, RTNLGRP_NSID, NULL, 0);
825 rtnl_set_sk_err(net, RTNLGRP_NSID, err);
828 static int __init net_ns_init(void)
830 struct net_generic *ng;
833 net_cachep = kmem_cache_create("net_namespace", sizeof(struct net),
837 /* Create workqueue for cleanup */
838 netns_wq = create_singlethread_workqueue("netns");
840 panic("Could not create netns workq");
843 ng = net_alloc_generic();
845 panic("Could not allocate generic netns");
847 rcu_assign_pointer(init_net.gen, ng);
849 mutex_lock(&net_mutex);
850 if (setup_net(&init_net, &init_user_ns))
851 panic("Could not setup the initial network namespace");
853 init_net_initialized = true;
856 list_add_tail_rcu(&init_net.list, &net_namespace_list);
859 mutex_unlock(&net_mutex);
861 if (register_pernet_subsys(&net_ns_ops))
862 panic("Could not register network namespace subsystems");
864 rtnl_register(PF_UNSPEC, RTM_NEWNSID, rtnl_net_newid, NULL,
865 RTNL_FLAG_DOIT_UNLOCKED);
866 rtnl_register(PF_UNSPEC, RTM_GETNSID, rtnl_net_getid, rtnl_net_dumpid,
867 RTNL_FLAG_DOIT_UNLOCKED);
872 pure_initcall(net_ns_init);
875 static int __register_pernet_operations(struct list_head *list,
876 struct pernet_operations *ops)
880 LIST_HEAD(net_exit_list);
882 list_add_tail(&ops->list, list);
883 if (ops->init || (ops->id && ops->size)) {
885 error = ops_init(ops, net);
888 list_add_tail(&net->exit_list, &net_exit_list);
894 /* If I have an error cleanup all namespaces I initialized */
895 list_del(&ops->list);
896 ops_exit_list(ops, &net_exit_list);
897 ops_free_list(ops, &net_exit_list);
901 static void __unregister_pernet_operations(struct pernet_operations *ops)
904 LIST_HEAD(net_exit_list);
906 list_del(&ops->list);
908 list_add_tail(&net->exit_list, &net_exit_list);
909 ops_exit_list(ops, &net_exit_list);
910 ops_free_list(ops, &net_exit_list);
915 static int __register_pernet_operations(struct list_head *list,
916 struct pernet_operations *ops)
918 if (!init_net_initialized) {
919 list_add_tail(&ops->list, list);
923 return ops_init(ops, &init_net);
926 static void __unregister_pernet_operations(struct pernet_operations *ops)
928 if (!init_net_initialized) {
929 list_del(&ops->list);
931 LIST_HEAD(net_exit_list);
932 list_add(&init_net.exit_list, &net_exit_list);
933 ops_exit_list(ops, &net_exit_list);
934 ops_free_list(ops, &net_exit_list);
938 #endif /* CONFIG_NET_NS */
940 static DEFINE_IDA(net_generic_ids);
942 static int register_pernet_operations(struct list_head *list,
943 struct pernet_operations *ops)
949 error = ida_get_new_above(&net_generic_ids, MIN_PERNET_OPS_ID, ops->id);
951 if (error == -EAGAIN) {
952 ida_pre_get(&net_generic_ids, GFP_KERNEL);
957 max_gen_ptrs = max(max_gen_ptrs, *ops->id + 1);
959 error = __register_pernet_operations(list, ops);
963 ida_remove(&net_generic_ids, *ops->id);
969 static void unregister_pernet_operations(struct pernet_operations *ops)
972 __unregister_pernet_operations(ops);
975 ida_remove(&net_generic_ids, *ops->id);
979 * register_pernet_subsys - register a network namespace subsystem
980 * @ops: pernet operations structure for the subsystem
982 * Register a subsystem which has init and exit functions
983 * that are called when network namespaces are created and
984 * destroyed respectively.
986 * When registered all network namespace init functions are
987 * called for every existing network namespace. Allowing kernel
988 * modules to have a race free view of the set of network namespaces.
990 * When a new network namespace is created all of the init
991 * methods are called in the order in which they were registered.
993 * When a network namespace is destroyed all of the exit methods
994 * are called in the reverse of the order with which they were
997 int register_pernet_subsys(struct pernet_operations *ops)
1000 mutex_lock(&net_mutex);
1001 error = register_pernet_operations(first_device, ops);
1002 mutex_unlock(&net_mutex);
1005 EXPORT_SYMBOL_GPL(register_pernet_subsys);
1008 * unregister_pernet_subsys - unregister a network namespace subsystem
1009 * @ops: pernet operations structure to manipulate
1011 * Remove the pernet operations structure from the list to be
1012 * used when network namespaces are created or destroyed. In
1013 * addition run the exit method for all existing network
1016 void unregister_pernet_subsys(struct pernet_operations *ops)
1018 mutex_lock(&net_mutex);
1019 unregister_pernet_operations(ops);
1020 mutex_unlock(&net_mutex);
1022 EXPORT_SYMBOL_GPL(unregister_pernet_subsys);
1025 * register_pernet_device - register a network namespace device
1026 * @ops: pernet operations structure for the subsystem
1028 * Register a device which has init and exit functions
1029 * that are called when network namespaces are created and
1030 * destroyed respectively.
1032 * When registered all network namespace init functions are
1033 * called for every existing network namespace. Allowing kernel
1034 * modules to have a race free view of the set of network namespaces.
1036 * When a new network namespace is created all of the init
1037 * methods are called in the order in which they were registered.
1039 * When a network namespace is destroyed all of the exit methods
1040 * are called in the reverse of the order with which they were
1043 int register_pernet_device(struct pernet_operations *ops)
1046 mutex_lock(&net_mutex);
1047 error = register_pernet_operations(&pernet_list, ops);
1048 if (!error && (first_device == &pernet_list))
1049 first_device = &ops->list;
1050 mutex_unlock(&net_mutex);
1053 EXPORT_SYMBOL_GPL(register_pernet_device);
1056 * unregister_pernet_device - unregister a network namespace netdevice
1057 * @ops: pernet operations structure to manipulate
1059 * Remove the pernet operations structure from the list to be
1060 * used when network namespaces are created or destroyed. In
1061 * addition run the exit method for all existing network
1064 void unregister_pernet_device(struct pernet_operations *ops)
1066 mutex_lock(&net_mutex);
1067 if (&ops->list == first_device)
1068 first_device = first_device->next;
1069 unregister_pernet_operations(ops);
1070 mutex_unlock(&net_mutex);
1072 EXPORT_SYMBOL_GPL(unregister_pernet_device);
1074 #ifdef CONFIG_NET_NS
1075 static struct ns_common *netns_get(struct task_struct *task)
1077 struct net *net = NULL;
1078 struct nsproxy *nsproxy;
1081 nsproxy = task->nsproxy;
1083 net = get_net(nsproxy->net_ns);
1086 return net ? &net->ns : NULL;
1089 static inline struct net *to_net_ns(struct ns_common *ns)
1091 return container_of(ns, struct net, ns);
1094 static void netns_put(struct ns_common *ns)
1096 put_net(to_net_ns(ns));
1099 static int netns_install(struct nsproxy *nsproxy, struct ns_common *ns)
1101 struct net *net = to_net_ns(ns);
1103 if (!ns_capable(net->user_ns, CAP_SYS_ADMIN) ||
1104 !ns_capable(current_user_ns(), CAP_SYS_ADMIN))
1107 put_net(nsproxy->net_ns);
1108 nsproxy->net_ns = get_net(net);
1112 static struct user_namespace *netns_owner(struct ns_common *ns)
1114 return to_net_ns(ns)->user_ns;
1117 const struct proc_ns_operations netns_operations = {
1119 .type = CLONE_NEWNET,
1122 .install = netns_install,
1123 .owner = netns_owner,