[deliverable/linux.git] / net / core / net_namespace.c

#include <linux/workqueue.h>
#include <linux/rtnetlink.h>
#include <linux/cache.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/idr.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>

/*
 *	Our network namespace constructor/destructor lists
 */

static LIST_HEAD(pernet_list);
static struct list_head *first_device = &pernet_list;
static DEFINE_MUTEX(net_mutex);

LIST_HEAD(net_namespace_list);
EXPORT_SYMBOL_GPL(net_namespace_list);

struct net init_net;
EXPORT_SYMBOL(init_net);

#define INITIAL_NET_GEN_PTRS	13 /* +1 for len +2 for rcu_head */

/*
 * setup_net runs the initializers for the network namespace object.
 */
static __net_init int setup_net(struct net *net)
{
	/* Must be called with net_mutex held */
	struct pernet_operations *ops;
	int error = 0;

	atomic_set(&net->count, 1);

#ifdef NETNS_REFCNT_DEBUG
	atomic_set(&net->use_count, 0);
#endif

	list_for_each_entry(ops, &pernet_list, list) {
		if (ops->init) {
			error = ops->init(net);
			if (error < 0)
				goto out_undo;
		}
	}
out:
	return error;

out_undo:
	/* Walk through the list backwards calling the exit functions
	 * for the pernet modules whose init functions did not fail.
	 */
	list_for_each_entry_continue_reverse(ops, &pernet_list, list) {
		if (ops->exit)
			ops->exit(net);
	}

	rcu_barrier();
	goto out;
}

static struct net_generic *net_alloc_generic(void)
{
	struct net_generic *ng;
	size_t generic_size = sizeof(struct net_generic) +
		INITIAL_NET_GEN_PTRS * sizeof(void *);

	ng = kzalloc(generic_size, GFP_KERNEL);
	if (ng)
		ng->len = INITIAL_NET_GEN_PTRS;

	return ng;
}

#ifdef CONFIG_NET_NS
static struct kmem_cache *net_cachep;
static struct workqueue_struct *netns_wq;

static struct net *net_alloc(void)
{
	struct net *net = NULL;
	struct net_generic *ng;

	ng = net_alloc_generic();
	if (!ng)
		goto out;

	net = kmem_cache_zalloc(net_cachep, GFP_KERNEL);
	if (!net)
		goto out_free;

	rcu_assign_pointer(net->gen, ng);
out:
	return net;

out_free:
	kfree(ng);
	goto out;
}

static void net_free(struct net *net)
{
#ifdef NETNS_REFCNT_DEBUG
	if (unlikely(atomic_read(&net->use_count) != 0)) {
		printk(KERN_EMERG "network namespace not free! Usage: %d\n",
			atomic_read(&net->use_count));
		return;
	}
#endif
	kfree(net->gen);
	kmem_cache_free(net_cachep, net);
}

static struct net *net_create(void)
{
	struct net *net;
	int rv;

	net = net_alloc();
	if (!net)
		return ERR_PTR(-ENOMEM);
	mutex_lock(&net_mutex);
	rv = setup_net(net);
	if (rv == 0) {
		rtnl_lock();
		list_add_tail(&net->list, &net_namespace_list);
		rtnl_unlock();
	}
	mutex_unlock(&net_mutex);
	if (rv < 0) {
		net_free(net);
		return ERR_PTR(rv);
	}
	return net;
}

struct net *copy_net_ns(unsigned long flags, struct net *old_net)
{
	if (!(flags & CLONE_NEWNET))
		return get_net(old_net);
	return net_create();
}

static void cleanup_net(struct work_struct *work)
{
	struct pernet_operations *ops;
	struct net *net;

	net = container_of(work, struct net, work);

	mutex_lock(&net_mutex);

	/* Don't let anyone else find us. */
	rtnl_lock();
	list_del(&net->list);
	rtnl_unlock();

	/* Run all of the network namespace exit methods */
	list_for_each_entry_reverse(ops, &pernet_list, list) {
		if (ops->exit)
			ops->exit(net);
	}

	mutex_unlock(&net_mutex);

	/* Ensure there are no outstanding rcu callbacks using this
	 * network namespace.
	 */
	rcu_barrier();

	/* Finally it is safe to free my network namespace structure */
	net_free(net);
}

void __put_net(struct net *net)
{
	/* Cleanup the network namespace in process context */
	INIT_WORK(&net->work, cleanup_net);
	queue_work(netns_wq, &net->work);
}
EXPORT_SYMBOL_GPL(__put_net);

#else
struct net *copy_net_ns(unsigned long flags, struct net *old_net)
{
	if (flags & CLONE_NEWNET)
		return ERR_PTR(-EINVAL);
	return old_net;
}
#endif

static int __init net_ns_init(void)
{
	struct net_generic *ng;

#ifdef CONFIG_NET_NS
	net_cachep = kmem_cache_create("net_namespace", sizeof(struct net),
					SMP_CACHE_BYTES,
					SLAB_PANIC, NULL);

	/* Create workqueue for cleanup */
	netns_wq = create_singlethread_workqueue("netns");
	if (!netns_wq)
		panic("Could not create netns workq");
#endif

	ng = net_alloc_generic();
	if (!ng)
		panic("Could not allocate generic netns");

	rcu_assign_pointer(init_net.gen, ng);

	mutex_lock(&net_mutex);
	if (setup_net(&init_net))
		panic("Could not setup the initial network namespace");

	rtnl_lock();
	list_add_tail(&init_net.list, &net_namespace_list);
	rtnl_unlock();

	mutex_unlock(&net_mutex);

	return 0;
}

pure_initcall(net_ns_init);

#ifdef CONFIG_NET_NS
static int register_pernet_operations(struct list_head *list,
				      struct pernet_operations *ops)
{
	struct net *net, *undo_net;
	int error;

	list_add_tail(&ops->list, list);
	if (ops->init) {
		for_each_net(net) {
			error = ops->init(net);
			if (error)
				goto out_undo;
		}
	}
	return 0;

out_undo:
	/* If I have an error cleanup all namespaces I initialized */
	list_del(&ops->list);
	if (ops->exit) {
		for_each_net(undo_net) {
			if (undo_net == net)
				goto undone;
			ops->exit(undo_net);
		}
	}
undone:
	return error;
}

static void unregister_pernet_operations(struct pernet_operations *ops)
{
	struct net *net;

	list_del(&ops->list);
	if (ops->exit)
		for_each_net(net)
			ops->exit(net);
}

#else

static int register_pernet_operations(struct list_head *list,
				      struct pernet_operations *ops)
{
	if (ops->init == NULL)
		return 0;
	return ops->init(&init_net);
}

static void unregister_pernet_operations(struct pernet_operations *ops)
{
	if (ops->exit)
		ops->exit(&init_net);
}
#endif

static DEFINE_IDA(net_generic_ids);

/**
 *      register_pernet_subsys - register a network namespace subsystem
 *	@ops:  pernet operations structure for the subsystem
 *
 *	Register a subsystem which has init and exit functions
 *	that are called when network namespaces are created and
 *	destroyed respectively.
 *
 *	When registered all network namespace init functions are
 *	called for every existing network namespace.  Allowing kernel
 *	modules to have a race free view of the set of network namespaces.
 *
 *	When a new network namespace is created all of the init
 *	methods are called in the order in which they were registered.
 *
 *	When a network namespace is destroyed all of the exit methods
 *	are called in the reverse of the order with which they were
 *	registered.
 */
int register_pernet_subsys(struct pernet_operations *ops)
{
	int error;
	mutex_lock(&net_mutex);
	error =  register_pernet_operations(first_device, ops);
	mutex_unlock(&net_mutex);
	return error;
}
EXPORT_SYMBOL_GPL(register_pernet_subsys);

/**
 *      unregister_pernet_subsys - unregister a network namespace subsystem
 *	@ops: pernet operations structure to manipulate
 *
 *	Remove the pernet operations structure from the list to be
 *	used when network namespaces are created or destroyed.  In
 *	addition run the exit method for all existing network
 *	namespaces.
 */
void unregister_pernet_subsys(struct pernet_operations *module)
{
	mutex_lock(&net_mutex);
	unregister_pernet_operations(module);
	mutex_unlock(&net_mutex);
}
EXPORT_SYMBOL_GPL(unregister_pernet_subsys);

int register_pernet_gen_subsys(int *id, struct pernet_operations *ops)
{
	int rv;

	mutex_lock(&net_mutex);
again:
	rv = ida_get_new_above(&net_generic_ids, 1, id);
	if (rv < 0) {
		if (rv == -EAGAIN) {
			ida_pre_get(&net_generic_ids, GFP_KERNEL);
			goto again;
		}
		goto out;
	}
	rv = register_pernet_operations(first_device, ops);
	if (rv < 0)
		ida_remove(&net_generic_ids, *id);
out:
	mutex_unlock(&net_mutex);
	return rv;
}
EXPORT_SYMBOL_GPL(register_pernet_gen_subsys);

void unregister_pernet_gen_subsys(int id, struct pernet_operations *ops)
{
	mutex_lock(&net_mutex);
	unregister_pernet_operations(ops);
	ida_remove(&net_generic_ids, id);
	mutex_unlock(&net_mutex);
}
EXPORT_SYMBOL_GPL(unregister_pernet_gen_subsys);

/**
 *      register_pernet_device - register a network namespace device
 *	@ops:  pernet operations structure for the subsystem
 *
 *	Register a device which has init and exit functions
 *	that are called when network namespaces are created and
 *	destroyed respectively.
 *
 *	When registered all network namespace init functions are
 *	called for every existing network namespace.  Allowing kernel
 *	modules to have a race free view of the set of network namespaces.
 *
 *	When a new network namespace is created all of the init
 *	methods are called in the order in which they were registered.
 *
 *	When a network namespace is destroyed all of the exit methods
 *	are called in the reverse of the order with which they were
 *	registered.
 */
int register_pernet_device(struct pernet_operations *ops)
{
	int error;
	mutex_lock(&net_mutex);
	error = register_pernet_operations(&pernet_list, ops);
	if (!error && (first_device == &pernet_list))
		first_device = &ops->list;
	mutex_unlock(&net_mutex);
	return error;
}
EXPORT_SYMBOL_GPL(register_pernet_device);

int register_pernet_gen_device(int *id, struct pernet_operations *ops)
{
	int error;
	mutex_lock(&net_mutex);
again:
	error = ida_get_new_above(&net_generic_ids, 1, id);
	if (error) {
		if (error == -EAGAIN) {
			ida_pre_get(&net_generic_ids, GFP_KERNEL);
			goto again;
		}
		goto out;
	}
	error = register_pernet_operations(&pernet_list, ops);
	if (error)
		ida_remove(&net_generic_ids, *id);
	else if (first_device == &pernet_list)
		first_device = &ops->list;
out:
	mutex_unlock(&net_mutex);
	return error;
}
EXPORT_SYMBOL_GPL(register_pernet_gen_device);

/**
 *      unregister_pernet_device - unregister a network namespace netdevice
 *	@ops: pernet operations structure to manipulate
 *
 *	Remove the pernet operations structure from the list to be
 *	used when network namespaces are created or destroyed.  In
 *	addition run the exit method for all existing network
 *	namespaces.
 */
void unregister_pernet_device(struct pernet_operations *ops)
{
	mutex_lock(&net_mutex);
	if (&ops->list == first_device)
		first_device = first_device->next;
	unregister_pernet_operations(ops);
	mutex_unlock(&net_mutex);
}
EXPORT_SYMBOL_GPL(unregister_pernet_device);

void unregister_pernet_gen_device(int id, struct pernet_operations *ops)
{
	mutex_lock(&net_mutex);
	if (&ops->list == first_device)
		first_device = first_device->next;
	unregister_pernet_operations(ops);
	ida_remove(&net_generic_ids, id);
	mutex_unlock(&net_mutex);
}
EXPORT_SYMBOL_GPL(unregister_pernet_gen_device);

static void net_generic_release(struct rcu_head *rcu)
{
	struct net_generic *ng;

	ng = container_of(rcu, struct net_generic, rcu);
	kfree(ng);
}

int net_assign_generic(struct net *net, int id, void *data)
{
	struct net_generic *ng, *old_ng;

	BUG_ON(!mutex_is_locked(&net_mutex));
	BUG_ON(id == 0);

	ng = old_ng = net->gen;
	if (old_ng->len >= id)
		goto assign;

	ng = kzalloc(sizeof(struct net_generic) +
			id * sizeof(void *), GFP_KERNEL);
	if (ng == NULL)
		return -ENOMEM;

	/*
	 * Some synchronisation notes:
	 *
	 * The net_generic explores the net->gen array inside rcu
	 * read section. Besides once set the net->gen->ptr[x]
	 * pointer never changes (see rules in netns/generic.h).
	 *
	 * That said, we simply duplicate this array and schedule
	 * the old copy for kfree after a grace period.
	 */

	ng->len = id;
	memcpy(&ng->ptr, &old_ng->ptr, old_ng->len);

	rcu_assign_pointer(net->gen, ng);
	call_rcu(&old_ng->rcu, net_generic_release);
assign:
	ng->ptr[id - 1] = data;
	return 0;
}
EXPORT_SYMBOL_GPL(net_assign_generic);
Commit	Line	Data
5f256bec EB	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>
9dd776b6	7	#include <linux/sched.h>
c93cf61f	8	#include <linux/idr.h>
5f256bec	9	#include <net/net_namespace.h>
dec827d1	10	#include <net/netns/generic.h>
5f256bec EB	11
	12	/*
	13	* Our network namespace constructor/destructor lists
	14	*/
	15
	16	static LIST_HEAD(pernet_list);
	17	static struct list_head *first_device = &pernet_list;
	18	static DEFINE_MUTEX(net_mutex);
	19
5f256bec	20	LIST_HEAD(net_namespace_list);
b76a461f	21	EXPORT_SYMBOL_GPL(net_namespace_list);
5f256bec	22
5f256bec	23	struct net init_net;
ff4b9502	24	EXPORT_SYMBOL(init_net);
5f256bec	25
dec827d1 PE	26	#define INITIAL_NET_GEN_PTRS 13 /* +1 for len +2 for rcu_head */
dec827d1 PE	27
5f256bec EB	28	/*
	29	* setup_net runs the initializers for the network namespace object.
	30	*/
1a2ee93d	31	static __net_init int setup_net(struct net *net)
5f256bec EB	32	{
	33	/* Must be called with net_mutex held */
	34	struct pernet_operations *ops;
486a87f1	35	int error = 0;
5f256bec	36
5f256bec	37	atomic_set(&net->count, 1);
486a87f1	38
5d1e4468	39	#ifdef NETNS_REFCNT_DEBUG
5f256bec	40	atomic_set(&net->use_count, 0);
5d1e4468	41	#endif
5f256bec	42
768f3591	43	list_for_each_entry(ops, &pernet_list, list) {
5f256bec EB	44	if (ops->init) {
	45	error = ops->init(net);
	46	if (error < 0)
	47	goto out_undo;
	48	}
	49	}
	50	out:
	51	return error;
768f3591	52
5f256bec EB	53	out_undo:
	54	/* Walk through the list backwards calling the exit functions
	55	* for the pernet modules whose init functions did not fail.
	56	*/
768f3591	57	list_for_each_entry_continue_reverse(ops, &pernet_list, list) {
5f256bec EB	58	if (ops->exit)
	59	ops->exit(net);
	60	}
310928d9 DL	61
310928d9 DL	62	rcu_barrier();
5f256bec EB	63	goto out;
	64	}
	65
486a87f1	66	static struct net_generic *net_alloc_generic(void)
6a1a3b9f	67	{
486a87f1 DL	68	struct net_generic *ng;
	69	size_t generic_size = sizeof(struct net_generic) +
	70	INITIAL_NET_GEN_PTRS * sizeof(void *);
	71
	72	ng = kzalloc(generic_size, GFP_KERNEL);
	73	if (ng)
	74	ng->len = INITIAL_NET_GEN_PTRS;
	75
	76	return ng;
6a1a3b9f PE	77	}
6a1a3b9f PE	78
ebe47d47 CN	79	#ifdef CONFIG_NET_NS
	80	static struct kmem_cache *net_cachep;
	81	static struct workqueue_struct *netns_wq;
	82
486a87f1	83	static struct net *net_alloc(void)
45a19b0a	84	{
486a87f1 DL	85	struct net *net = NULL;
	86	struct net_generic *ng;
	87
	88	ng = net_alloc_generic();
	89	if (!ng)
	90	goto out;
	91
	92	net = kmem_cache_zalloc(net_cachep, GFP_KERNEL);
45a19b0a	93	if (!net)
486a87f1	94	goto out_free;
45a19b0a	95
486a87f1 DL	96	rcu_assign_pointer(net->gen, ng);
	97	out:
	98	return net;
	99
	100	out_free:
	101	kfree(ng);
	102	goto out;
	103	}
	104
	105	static void net_free(struct net *net)
	106	{
5d1e4468	107	#ifdef NETNS_REFCNT_DEBUG
45a19b0a JFS	108	if (unlikely(atomic_read(&net->use_count) != 0)) {
	109	printk(KERN_EMERG "network namespace not free! Usage: %d\n",
	110	atomic_read(&net->use_count));
	111	return;
	112	}
5d1e4468	113	#endif
4ef079cc	114	kfree(net->gen);
45a19b0a JFS	115	kmem_cache_free(net_cachep, net);
	116	}
	117
088eb2d9	118	static struct net *net_create(void)
9dd776b6	119	{
088eb2d9 AD	120	struct net *net;
088eb2d9 AD	121	int rv;
9dd776b6	122
088eb2d9 AD	123	net = net_alloc();
	124	if (!net)
	125	return ERR_PTR(-ENOMEM);
9dd776b6	126	mutex_lock(&net_mutex);
088eb2d9 AD	127	rv = setup_net(net);
088eb2d9 AD	128	if (rv == 0) {
486a87f1	129	rtnl_lock();
088eb2d9	130	list_add_tail(&net->list, &net_namespace_list);
486a87f1 DL	131	rtnl_unlock();
486a87f1 DL	132	}
9dd776b6	133	mutex_unlock(&net_mutex);
088eb2d9 AD	134	if (rv < 0) {
	135	net_free(net);
	136	return ERR_PTR(rv);
	137	}
	138	return net;
	139	}
486a87f1	140
088eb2d9 AD	141	struct net copy_net_ns(unsigned long flags, struct net old_net)
	142	{
	143	if (!(flags & CLONE_NEWNET))
	144	return get_net(old_net);
	145	return net_create();
9dd776b6 EB	146	}
9dd776b6 EB	147
6a1a3b9f PE	148	static void cleanup_net(struct work_struct *work)
	149	{
	150	struct pernet_operations *ops;
	151	struct net *net;
	152
	153	net = container_of(work, struct net, work);
	154
	155	mutex_lock(&net_mutex);
	156
	157	/* Don't let anyone else find us. */
	158	rtnl_lock();
	159	list_del(&net->list);
	160	rtnl_unlock();
	161
	162	/* Run all of the network namespace exit methods */
	163	list_for_each_entry_reverse(ops, &pernet_list, list) {
	164	if (ops->exit)
	165	ops->exit(net);
	166	}
	167
	168	mutex_unlock(&net_mutex);
	169
	170	/* Ensure there are no outstanding rcu callbacks using this
	171	* network namespace.
	172	*/
	173	rcu_barrier();
	174
	175	/* Finally it is safe to free my network namespace structure */
	176	net_free(net);
	177	}
	178
	179	void __put_net(struct net *net)
	180	{
	181	/* Cleanup the network namespace in process context */
	182	INIT_WORK(&net->work, cleanup_net);
3ef1355d	183	queue_work(netns_wq, &net->work);
6a1a3b9f PE	184	}
	185	EXPORT_SYMBOL_GPL(__put_net);
	186
	187	#else
	188	struct net copy_net_ns(unsigned long flags, struct net old_net)
	189	{
	190	if (flags & CLONE_NEWNET)
	191	return ERR_PTR(-EINVAL);
	192	return old_net;
	193	}
	194	#endif
	195
5f256bec EB	196	static int __init net_ns_init(void)
5f256bec EB	197	{
486a87f1	198	struct net_generic *ng;
5f256bec	199
d57a9212	200	#ifdef CONFIG_NET_NS
5f256bec EB	201	net_cachep = kmem_cache_create("net_namespace", sizeof(struct net),
	202	SMP_CACHE_BYTES,
	203	SLAB_PANIC, NULL);
3ef1355d BT	204
	205	/* Create workqueue for cleanup */
	206	netns_wq = create_singlethread_workqueue("netns");
	207	if (!netns_wq)
	208	panic("Could not create netns workq");
d57a9212	209	#endif
3ef1355d	210
486a87f1 DL	211	ng = net_alloc_generic();
	212	if (!ng)
	213	panic("Could not allocate generic netns");
	214
	215	rcu_assign_pointer(init_net.gen, ng);
	216
5f256bec	217	mutex_lock(&net_mutex);
ca0f3112 SH	218	if (setup_net(&init_net))
ca0f3112 SH	219	panic("Could not setup the initial network namespace");
5f256bec	220
f4618d39	221	rtnl_lock();
5f256bec	222	list_add_tail(&init_net.list, &net_namespace_list);
f4618d39	223	rtnl_unlock();
5f256bec EB	224
5f256bec EB	225	mutex_unlock(&net_mutex);
5f256bec EB	226
	227	return 0;
	228	}
	229
	230	pure_initcall(net_ns_init);
	231
ed160e83	232	#ifdef CONFIG_NET_NS
5f256bec EB	233	static int register_pernet_operations(struct list_head *list,
	234	struct pernet_operations *ops)
	235	{
	236	struct net net, undo_net;
	237	int error;
	238
5f256bec	239	list_add_tail(&ops->list, list);
1dba323b PE	240	if (ops->init) {
1dba323b PE	241	for_each_net(net) {
5f256bec EB	242	error = ops->init(net);
	243	if (error)
	244	goto out_undo;
	245	}
	246	}
1dba323b	247	return 0;
5f256bec EB	248
	249	out_undo:
	250	/* If I have an error cleanup all namespaces I initialized */
	251	list_del(&ops->list);
1dba323b PE	252	if (ops->exit) {
	253	for_each_net(undo_net) {
	254	if (undo_net == net)
	255	goto undone;
5f256bec	256	ops->exit(undo_net);
1dba323b	257	}
5f256bec EB	258	}
5f256bec EB	259	undone:
1dba323b	260	return error;
5f256bec EB	261	}
	262
	263	static void unregister_pernet_operations(struct pernet_operations *ops)
	264	{
	265	struct net *net;
	266
	267	list_del(&ops->list);
1dba323b PE	268	if (ops->exit)
1dba323b PE	269	for_each_net(net)
5f256bec EB	270	ops->exit(net);
	271	}
	272
ed160e83 DL	273	#else
	274
	275	static int register_pernet_operations(struct list_head *list,
	276	struct pernet_operations *ops)
	277	{
	278	if (ops->init == NULL)
	279	return 0;
	280	return ops->init(&init_net);
	281	}
	282
	283	static void unregister_pernet_operations(struct pernet_operations *ops)
	284	{
	285	if (ops->exit)
	286	ops->exit(&init_net);
	287	}
	288	#endif
	289
c93cf61f PE	290	static DEFINE_IDA(net_generic_ids);
c93cf61f PE	291
5f256bec EB	292	/**
	293	* register_pernet_subsys - register a network namespace subsystem
	294	* @ops: pernet operations structure for the subsystem
	295	*
	296	* Register a subsystem which has init and exit functions
	297	* that are called when network namespaces are created and
	298	* destroyed respectively.
	299	*
	300	* When registered all network namespace init functions are
	301	* called for every existing network namespace. Allowing kernel
	302	* modules to have a race free view of the set of network namespaces.
	303	*
	304	* When a new network namespace is created all of the init
	305	* methods are called in the order in which they were registered.
	306	*
	307	* When a network namespace is destroyed all of the exit methods
	308	* are called in the reverse of the order with which they were
	309	* registered.
	310	*/
	311	int register_pernet_subsys(struct pernet_operations *ops)
	312	{
	313	int error;
	314	mutex_lock(&net_mutex);
	315	error = register_pernet_operations(first_device, ops);
	316	mutex_unlock(&net_mutex);
	317	return error;
	318	}
	319	EXPORT_SYMBOL_GPL(register_pernet_subsys);
	320
	321	/**
	322	* unregister_pernet_subsys - unregister a network namespace subsystem
	323	* @ops: pernet operations structure to manipulate
	324	*
	325	* Remove the pernet operations structure from the list to be
53379e57	326	* used when network namespaces are created or destroyed. In
5f256bec EB	327	* addition run the exit method for all existing network
	328	* namespaces.
	329	*/
	330	void unregister_pernet_subsys(struct pernet_operations *module)
	331	{
	332	mutex_lock(&net_mutex);
	333	unregister_pernet_operations(module);
	334	mutex_unlock(&net_mutex);
	335	}
	336	EXPORT_SYMBOL_GPL(unregister_pernet_subsys);
	337
485ac57b AD	338	int register_pernet_gen_subsys(int id, struct pernet_operations ops)
	339	{
	340	int rv;
	341
	342	mutex_lock(&net_mutex);
	343	again:
	344	rv = ida_get_new_above(&net_generic_ids, 1, id);
	345	if (rv < 0) {
	346	if (rv == -EAGAIN) {
	347	ida_pre_get(&net_generic_ids, GFP_KERNEL);
	348	goto again;
	349	}
	350	goto out;
	351	}
	352	rv = register_pernet_operations(first_device, ops);
	353	if (rv < 0)
	354	ida_remove(&net_generic_ids, *id);
485ac57b	355	out:
357f5b0b	356	mutex_unlock(&net_mutex);
485ac57b AD	357	return rv;
	358	}
	359	EXPORT_SYMBOL_GPL(register_pernet_gen_subsys);
	360
	361	void unregister_pernet_gen_subsys(int id, struct pernet_operations *ops)
	362	{
	363	mutex_lock(&net_mutex);
	364	unregister_pernet_operations(ops);
	365	ida_remove(&net_generic_ids, id);
	366	mutex_unlock(&net_mutex);
	367	}
	368	EXPORT_SYMBOL_GPL(unregister_pernet_gen_subsys);
	369
5f256bec EB	370	/**
	371	* register_pernet_device - register a network namespace device
	372	* @ops: pernet operations structure for the subsystem
	373	*
	374	* Register a device which has init and exit functions
	375	* that are called when network namespaces are created and
	376	* destroyed respectively.
	377	*
	378	* When registered all network namespace init functions are
	379	* called for every existing network namespace. Allowing kernel
	380	* modules to have a race free view of the set of network namespaces.
	381	*
	382	* When a new network namespace is created all of the init
	383	* methods are called in the order in which they were registered.
	384	*
	385	* When a network namespace is destroyed all of the exit methods
	386	* are called in the reverse of the order with which they were
	387	* registered.
	388	*/
	389	int register_pernet_device(struct pernet_operations *ops)
	390	{
	391	int error;
	392	mutex_lock(&net_mutex);
	393	error = register_pernet_operations(&pernet_list, ops);
	394	if (!error && (first_device == &pernet_list))
	395	first_device = &ops->list;
	396	mutex_unlock(&net_mutex);
	397	return error;
	398	}
	399	EXPORT_SYMBOL_GPL(register_pernet_device);
	400
c93cf61f PE	401	int register_pernet_gen_device(int id, struct pernet_operations ops)
	402	{
	403	int error;
	404	mutex_lock(&net_mutex);
	405	again:
	406	error = ida_get_new_above(&net_generic_ids, 1, id);
	407	if (error) {
	408	if (error == -EAGAIN) {
	409	ida_pre_get(&net_generic_ids, GFP_KERNEL);
	410	goto again;
	411	}
	412	goto out;
	413	}
	414	error = register_pernet_operations(&pernet_list, ops);
	415	if (error)
	416	ida_remove(&net_generic_ids, *id);
	417	else if (first_device == &pernet_list)
	418	first_device = &ops->list;
	419	out:
	420	mutex_unlock(&net_mutex);
	421	return error;
	422	}
	423	EXPORT_SYMBOL_GPL(register_pernet_gen_device);
	424
5f256bec EB	425	/**
	426	* unregister_pernet_device - unregister a network namespace netdevice
	427	* @ops: pernet operations structure to manipulate
	428	*
	429	* Remove the pernet operations structure from the list to be
53379e57	430	* used when network namespaces are created or destroyed. In
5f256bec EB	431	* addition run the exit method for all existing network
	432	* namespaces.
	433	*/
	434	void unregister_pernet_device(struct pernet_operations *ops)
	435	{
	436	mutex_lock(&net_mutex);
	437	if (&ops->list == first_device)
	438	first_device = first_device->next;
	439	unregister_pernet_operations(ops);
	440	mutex_unlock(&net_mutex);
	441	}
	442	EXPORT_SYMBOL_GPL(unregister_pernet_device);
c93cf61f PE	443
	444	void unregister_pernet_gen_device(int id, struct pernet_operations *ops)
	445	{
	446	mutex_lock(&net_mutex);
	447	if (&ops->list == first_device)
	448	first_device = first_device->next;
	449	unregister_pernet_operations(ops);
	450	ida_remove(&net_generic_ids, id);
	451	mutex_unlock(&net_mutex);
	452	}
	453	EXPORT_SYMBOL_GPL(unregister_pernet_gen_device);
dec827d1 PE	454
	455	static void net_generic_release(struct rcu_head *rcu)
	456	{
	457	struct net_generic *ng;
	458
	459	ng = container_of(rcu, struct net_generic, rcu);
	460	kfree(ng);
	461	}
	462
	463	int net_assign_generic(struct net net, int id, void data)
	464	{
	465	struct net_generic ng, old_ng;
	466
	467	BUG_ON(!mutex_is_locked(&net_mutex));
	468	BUG_ON(id == 0);
	469
	470	ng = old_ng = net->gen;
	471	if (old_ng->len >= id)
	472	goto assign;
	473
	474	ng = kzalloc(sizeof(struct net_generic) +
	475	id * sizeof(void *), GFP_KERNEL);
	476	if (ng == NULL)
	477	return -ENOMEM;
	478
	479	/*
	480	* Some synchronisation notes:
	481	*
	482	* The net_generic explores the net->gen array inside rcu
	483	* read section. Besides once set the net->gen->ptr[x]
	484	* pointer never changes (see rules in netns/generic.h).
	485	*
	486	* That said, we simply duplicate this array and schedule
	487	* the old copy for kfree after a grace period.
	488	*/
	489
	490	ng->len = id;
dec827d1 PE	491	memcpy(&ng->ptr, &old_ng->ptr, old_ng->len);
	492
	493	rcu_assign_pointer(net->gen, ng);
	494	call_rcu(&old_ng->rcu, net_generic_release);
	495	assign:
	496	ng->ptr[id - 1] = data;
	497	return 0;
	498	}
	499	EXPORT_SYMBOL_GPL(net_assign_generic);