[mirror_ubuntu-zesty-kernel.git] / net / netfilter / core.c

/* netfilter.c: look after the filters for various protocols.
 * Heavily influenced by the old firewall.c by David Bonn and Alan Cox.
 *
 * Thanks to Rob `CmdrTaco' Malda for not influencing this code in any
 * way.
 *
 * Rusty Russell (C)2000 -- This code is GPL.
 * Patrick McHardy (c) 2006-2012
 */
#include <linux/kernel.h>
#include <linux/netfilter.h>
#include <net/protocol.h>
#include <linux/init.h>
#include <linux/skbuff.h>
#include <linux/wait.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/if.h>
#include <linux/netdevice.h>
#include <linux/netfilter_ipv6.h>
#include <linux/inetdevice.h>
#include <linux/proc_fs.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/rcupdate.h>
#include <net/net_namespace.h>
#include <net/sock.h>

#include "nf_internals.h"

static DEFINE_MUTEX(afinfo_mutex);

const struct nf_afinfo __rcu *nf_afinfo[NFPROTO_NUMPROTO] __read_mostly;
EXPORT_SYMBOL(nf_afinfo);
const struct nf_ipv6_ops __rcu *nf_ipv6_ops __read_mostly;
EXPORT_SYMBOL_GPL(nf_ipv6_ops);

DEFINE_PER_CPU(bool, nf_skb_duplicated);
EXPORT_SYMBOL_GPL(nf_skb_duplicated);

int nf_register_afinfo(const struct nf_afinfo *afinfo)
{
	mutex_lock(&afinfo_mutex);
	RCU_INIT_POINTER(nf_afinfo[afinfo->family], afinfo);
	mutex_unlock(&afinfo_mutex);
	return 0;
}
EXPORT_SYMBOL_GPL(nf_register_afinfo);

void nf_unregister_afinfo(const struct nf_afinfo *afinfo)
{
	mutex_lock(&afinfo_mutex);
	RCU_INIT_POINTER(nf_afinfo[afinfo->family], NULL);
	mutex_unlock(&afinfo_mutex);
	synchronize_rcu();
}
EXPORT_SYMBOL_GPL(nf_unregister_afinfo);

#ifdef HAVE_JUMP_LABEL
struct static_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
EXPORT_SYMBOL(nf_hooks_needed);
#endif

static DEFINE_MUTEX(nf_hook_mutex);
#define nf_entry_dereference(e) \
	rcu_dereference_protected(e, lockdep_is_held(&nf_hook_mutex))

static struct nf_hook_entry __rcu **nf_hook_entry_head(struct net *net, const struct nf_hook_ops *reg)
{
	if (reg->pf != NFPROTO_NETDEV)
		return net->nf.hooks[reg->pf]+reg->hooknum;

#ifdef CONFIG_NETFILTER_INGRESS
	if (reg->hooknum == NF_NETDEV_INGRESS) {
		if (reg->dev && dev_net(reg->dev) == net)
			return &reg->dev->nf_hooks_ingress;
	}
#endif
	return NULL;
}

int nf_register_net_hook(struct net *net, const struct nf_hook_ops *reg)
{
	struct nf_hook_entry __rcu **pp;
	struct nf_hook_entry *entry, *p;

	if (reg->pf == NFPROTO_NETDEV) {
#ifndef CONFIG_NETFILTER_INGRESS
		if (reg->hooknum == NF_NETDEV_INGRESS)
			return -EOPNOTSUPP;
#endif
		if (reg->hooknum != NF_NETDEV_INGRESS ||
		    !reg->dev || dev_net(reg->dev) != net)
			return -EINVAL;
	}

	pp = nf_hook_entry_head(net, reg);
	if (!pp)
		return -EINVAL;

	entry = kmalloc(sizeof(*entry), GFP_KERNEL);
	if (!entry)
		return -ENOMEM;

	nf_hook_entry_init(entry, reg);

	mutex_lock(&nf_hook_mutex);

	/* Find the spot in the list */
	for (; (p = nf_entry_dereference(*pp)) != NULL; pp = &p->next) {
		if (reg->priority < nf_hook_entry_priority(p))
			break;
	}
	rcu_assign_pointer(entry->next, p);
	rcu_assign_pointer(*pp, entry);

	mutex_unlock(&nf_hook_mutex);
#ifdef CONFIG_NETFILTER_INGRESS
	if (reg->pf == NFPROTO_NETDEV && reg->hooknum == NF_NETDEV_INGRESS)
		net_inc_ingress_queue();
#endif
#ifdef HAVE_JUMP_LABEL
	static_key_slow_inc(&nf_hooks_needed[reg->pf][reg->hooknum]);
#endif
	return 0;
}
EXPORT_SYMBOL(nf_register_net_hook);

void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *reg)
{
	struct nf_hook_entry __rcu **pp;
	struct nf_hook_entry *p;

	pp = nf_hook_entry_head(net, reg);
	if (WARN_ON_ONCE(!pp))
		return;

	mutex_lock(&nf_hook_mutex);
	for (; (p = nf_entry_dereference(*pp)) != NULL; pp = &p->next) {
		if (nf_hook_entry_ops(p) == reg) {
			rcu_assign_pointer(*pp, p->next);
			break;
		}
	}
	mutex_unlock(&nf_hook_mutex);
	if (!p) {
		WARN(1, "nf_unregister_net_hook: hook not found!\n");
		return;
	}
#ifdef CONFIG_NETFILTER_INGRESS
	if (reg->pf == NFPROTO_NETDEV && reg->hooknum == NF_NETDEV_INGRESS)
		net_dec_ingress_queue();
#endif
#ifdef HAVE_JUMP_LABEL
	static_key_slow_dec(&nf_hooks_needed[reg->pf][reg->hooknum]);
#endif
	synchronize_net();
	nf_queue_nf_hook_drop(net, p);
	/* other cpu might still process nfqueue verdict that used reg */
	synchronize_net();
	kfree(p);
}
EXPORT_SYMBOL(nf_unregister_net_hook);

int nf_register_net_hooks(struct net *net, const struct nf_hook_ops *reg,
			  unsigned int n)
{
	unsigned int i;
	int err = 0;

	for (i = 0; i < n; i++) {
		err = nf_register_net_hook(net, &reg[i]);
		if (err)
			goto err;
	}
	return err;

err:
	if (i > 0)
		nf_unregister_net_hooks(net, reg, i);
	return err;
}
EXPORT_SYMBOL(nf_register_net_hooks);

void nf_unregister_net_hooks(struct net *net, const struct nf_hook_ops *reg,
			     unsigned int n)
{
	while (n-- > 0)
		nf_unregister_net_hook(net, &reg[n]);
}
EXPORT_SYMBOL(nf_unregister_net_hooks);

static LIST_HEAD(nf_hook_list);

static int _nf_register_hook(struct nf_hook_ops *reg)
{
	struct net *net, *last;
	int ret;

	for_each_net(net) {
		ret = nf_register_net_hook(net, reg);
		if (ret && ret != -ENOENT)
			goto rollback;
	}
	list_add_tail(&reg->list, &nf_hook_list);

	return 0;
rollback:
	last = net;
	for_each_net(net) {
		if (net == last)
			break;
		nf_unregister_net_hook(net, reg);
	}
	return ret;
}

int nf_register_hook(struct nf_hook_ops *reg)
{
	int ret;

	rtnl_lock();
	ret = _nf_register_hook(reg);
	rtnl_unlock();

	return ret;
}
EXPORT_SYMBOL(nf_register_hook);

static void _nf_unregister_hook(struct nf_hook_ops *reg)
{
	struct net *net;

	list_del(&reg->list);
	for_each_net(net)
		nf_unregister_net_hook(net, reg);
}

void nf_unregister_hook(struct nf_hook_ops *reg)
{
	rtnl_lock();
	_nf_unregister_hook(reg);
	rtnl_unlock();
}
EXPORT_SYMBOL(nf_unregister_hook);

int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n)
{
	unsigned int i;
	int err = 0;

	for (i = 0; i < n; i++) {
		err = nf_register_hook(&reg[i]);
		if (err)
			goto err;
	}
	return err;

err:
	if (i > 0)
		nf_unregister_hooks(reg, i);
	return err;
}
EXPORT_SYMBOL(nf_register_hooks);

/* Caller MUST take rtnl_lock() */
int _nf_register_hooks(struct nf_hook_ops *reg, unsigned int n)
{
	unsigned int i;
	int err = 0;

	for (i = 0; i < n; i++) {
		err = _nf_register_hook(&reg[i]);
		if (err)
			goto err;
	}
	return err;

err:
	if (i > 0)
		_nf_unregister_hooks(reg, i);
	return err;
}
EXPORT_SYMBOL(_nf_register_hooks);

void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n)
{
	while (n-- > 0)
		nf_unregister_hook(&reg[n]);
}
EXPORT_SYMBOL(nf_unregister_hooks);

/* Caller MUST take rtnl_lock */
void _nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n)
{
	while (n-- > 0)
		_nf_unregister_hook(&reg[n]);
}
EXPORT_SYMBOL(_nf_unregister_hooks);

/* Returns 1 if okfn() needs to be executed by the caller,
 * -EPERM for NF_DROP, 0 otherwise.  Caller must hold rcu_read_lock. */
int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state,
		 struct nf_hook_entry *entry)
{
	unsigned int verdict;
	int ret;

	do {
		verdict = nf_hook_entry_hookfn(entry, skb, state);
		switch (verdict & NF_VERDICT_MASK) {
		case NF_ACCEPT:
			entry = rcu_dereference(entry->next);
			break;
		case NF_DROP:
			kfree_skb(skb);
			ret = NF_DROP_GETERR(verdict);
			if (ret == 0)
				ret = -EPERM;
			return ret;
		case NF_QUEUE:
			ret = nf_queue(skb, state, &entry, verdict);
			if (ret == 1 && entry)
				continue;
			return ret;
		default:
			/* Implicit handling for NF_STOLEN, as well as any other
			 * non conventional verdicts.
			 */
			return 0;
		}
	} while (entry);

	return 1;
}
EXPORT_SYMBOL(nf_hook_slow);


int skb_make_writable(struct sk_buff *skb, unsigned int writable_len)
{
	if (writable_len > skb->len)
		return 0;

	/* Not exclusive use of packet?  Must copy. */
	if (!skb_cloned(skb)) {
		if (writable_len <= skb_headlen(skb))
			return 1;
	} else if (skb_clone_writable(skb, writable_len))
		return 1;

	if (writable_len <= skb_headlen(skb))
		writable_len = 0;
	else
		writable_len -= skb_headlen(skb);

	return !!__pskb_pull_tail(skb, writable_len);
}
EXPORT_SYMBOL(skb_make_writable);

/* This needs to be compiled in any case to avoid dependencies between the
 * nfnetlink_queue code and nf_conntrack.
 */
struct nfnl_ct_hook __rcu *nfnl_ct_hook __read_mostly;
EXPORT_SYMBOL_GPL(nfnl_ct_hook);

#if IS_ENABLED(CONFIG_NF_CONNTRACK)
/* This does not belong here, but locally generated errors need it if connection
   tracking in use: without this, connection may not be in hash table, and hence
   manufactured ICMP or RST packets will not be associated with it. */
void (*ip_ct_attach)(struct sk_buff *, const struct sk_buff *)
		__rcu __read_mostly;
EXPORT_SYMBOL(ip_ct_attach);

void nf_ct_attach(struct sk_buff *new, const struct sk_buff *skb)
{
	void (*attach)(struct sk_buff *, const struct sk_buff *);

	if (skb->nfct) {
		rcu_read_lock();
		attach = rcu_dereference(ip_ct_attach);
		if (attach)
			attach(new, skb);
		rcu_read_unlock();
	}
}
EXPORT_SYMBOL(nf_ct_attach);

void (*nf_ct_destroy)(struct nf_conntrack *) __rcu __read_mostly;
EXPORT_SYMBOL(nf_ct_destroy);

void nf_conntrack_destroy(struct nf_conntrack *nfct)
{
	void (*destroy)(struct nf_conntrack *);

	rcu_read_lock();
	destroy = rcu_dereference(nf_ct_destroy);
	BUG_ON(destroy == NULL);
	destroy(nfct);
	rcu_read_unlock();
}
EXPORT_SYMBOL(nf_conntrack_destroy);

/* Built-in default zone used e.g. by modules. */
const struct nf_conntrack_zone nf_ct_zone_dflt = {
	.id	= NF_CT_DEFAULT_ZONE_ID,
	.dir	= NF_CT_DEFAULT_ZONE_DIR,
};
EXPORT_SYMBOL_GPL(nf_ct_zone_dflt);
#endif /* CONFIG_NF_CONNTRACK */

#ifdef CONFIG_NF_NAT_NEEDED
void (*nf_nat_decode_session_hook)(struct sk_buff *, struct flowi *);
EXPORT_SYMBOL(nf_nat_decode_session_hook);
#endif

static int nf_register_hook_list(struct net *net)
{
	struct nf_hook_ops *elem;
	int ret;

	rtnl_lock();
	list_for_each_entry(elem, &nf_hook_list, list) {
		ret = nf_register_net_hook(net, elem);
		if (ret && ret != -ENOENT)
			goto out_undo;
	}
	rtnl_unlock();
	return 0;

out_undo:
	list_for_each_entry_continue_reverse(elem, &nf_hook_list, list)
		nf_unregister_net_hook(net, elem);
	rtnl_unlock();
	return ret;
}

static void nf_unregister_hook_list(struct net *net)
{
	struct nf_hook_ops *elem;

	rtnl_lock();
	list_for_each_entry(elem, &nf_hook_list, list)
		nf_unregister_net_hook(net, elem);
	rtnl_unlock();
}

static int __net_init netfilter_net_init(struct net *net)
{
	int i, h, ret;

	for (i = 0; i < ARRAY_SIZE(net->nf.hooks); i++) {
		for (h = 0; h < NF_MAX_HOOKS; h++)
			RCU_INIT_POINTER(net->nf.hooks[i][h], NULL);
	}

#ifdef CONFIG_PROC_FS
	net->nf.proc_netfilter = proc_net_mkdir(net, "netfilter",
						net->proc_net);
	if (!net->nf.proc_netfilter) {
		if (!net_eq(net, &init_net))
			pr_err("cannot create netfilter proc entry");

		return -ENOMEM;
	}
#endif
	ret = nf_register_hook_list(net);
	if (ret)
		remove_proc_entry("netfilter", net->proc_net);

	return ret;
}

static void __net_exit netfilter_net_exit(struct net *net)
{
	nf_unregister_hook_list(net);
	remove_proc_entry("netfilter", net->proc_net);
}

static struct pernet_operations netfilter_net_ops = {
	.init = netfilter_net_init,
	.exit = netfilter_net_exit,
};

int __init netfilter_init(void)
{
	int ret;

	ret = register_pernet_subsys(&netfilter_net_ops);
	if (ret < 0)
		goto err;

	ret = netfilter_log_init();
	if (ret < 0)
		goto err_pernet;

	return 0;
err_pernet:
	unregister_pernet_subsys(&netfilter_net_ops);
err:
	return ret;
}
Commit	Line	Data
601e68e1	1	/* netfilter.c: look after the filters for various protocols.
f6ebe77f HW	2	* Heavily influenced by the old firewall.c by David Bonn and Alan Cox.
	3	*
	4	* Thanks to Rob `CmdrTaco' Malda for not influencing this code in any
	5	* way.
	6	*
	7	* Rusty Russell (C)2000 -- This code is GPL.
f229f6ce	8	* Patrick McHardy (c) 2006-2012
f6ebe77f	9	*/
f6ebe77f HW	10	#include <linux/kernel.h>
	11	#include <linux/netfilter.h>
	12	#include <net/protocol.h>
	13	#include <linux/init.h>
	14	#include <linux/skbuff.h>
	15	#include <linux/wait.h>
	16	#include <linux/module.h>
	17	#include <linux/interrupt.h>
	18	#include <linux/if.h>
	19	#include <linux/netdevice.h>
56768644	20	#include <linux/netfilter_ipv6.h>
f6ebe77f HW	21	#include <linux/inetdevice.h>
f6ebe77f HW	22	#include <linux/proc_fs.h>
d486dd1f	23	#include <linux/mutex.h>
5a0e3ad6	24	#include <linux/slab.h>
e3b37f11	25	#include <linux/rcupdate.h>
457c4cbc	26	#include <net/net_namespace.h>
f6ebe77f HW	27	#include <net/sock.h>
	28
	29	#include "nf_internals.h"
	30
d486dd1f	31	static DEFINE_MUTEX(afinfo_mutex);
bce8032e	32
0906a372	33	const struct nf_afinfo __rcu *nf_afinfo[NFPROTO_NUMPROTO] __read_mostly;
bce8032e	34	EXPORT_SYMBOL(nf_afinfo);
2a7851bf FW	35	const struct nf_ipv6_ops __rcu *nf_ipv6_ops __read_mostly;
2a7851bf FW	36	EXPORT_SYMBOL_GPL(nf_ipv6_ops);
bce8032e	37
e7c8899f FW	38	DEFINE_PER_CPU(bool, nf_skb_duplicated);
	39	EXPORT_SYMBOL_GPL(nf_skb_duplicated);
	40
1e796fda	41	int nf_register_afinfo(const struct nf_afinfo *afinfo)
bce8032e	42	{
7926dbfa	43	mutex_lock(&afinfo_mutex);
a9b3cd7f	44	RCU_INIT_POINTER(nf_afinfo[afinfo->family], afinfo);
d486dd1f	45	mutex_unlock(&afinfo_mutex);
bce8032e PM	46	return 0;
	47	}
	48	EXPORT_SYMBOL_GPL(nf_register_afinfo);
	49
1e796fda	50	void nf_unregister_afinfo(const struct nf_afinfo *afinfo)
bce8032e	51	{
d486dd1f	52	mutex_lock(&afinfo_mutex);
a9b3cd7f	53	RCU_INIT_POINTER(nf_afinfo[afinfo->family], NULL);
d486dd1f	54	mutex_unlock(&afinfo_mutex);
bce8032e PM	55	synchronize_rcu();
	56	}
	57	EXPORT_SYMBOL_GPL(nf_unregister_afinfo);
	58
d1c85c2e	59	#ifdef HAVE_JUMP_LABEL
c5905afb	60	struct static_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
a2d7ec58 ED	61	EXPORT_SYMBOL(nf_hooks_needed);
	62	#endif
	63
fd706d69	64	static DEFINE_MUTEX(nf_hook_mutex);
e3b37f11 AC	65	#define nf_entry_dereference(e) \
e3b37f11 AC	66	rcu_dereference_protected(e, lockdep_is_held(&nf_hook_mutex))
f6ebe77f	67
bd3769bf	68	static struct nf_hook_entry __rcu *nf_hook_entry_head(struct net net, const struct nf_hook_ops *reg)
f6ebe77f	69	{
0edcf282	70	if (reg->pf != NFPROTO_NETDEV)
bd3769bf LT	71	return net->nf.hooks[reg->pf]+reg->hooknum;
bd3769bf LT	72
e687ad60	73	#ifdef CONFIG_NETFILTER_INGRESS
bd3769bf	74	if (reg->hooknum == NF_NETDEV_INGRESS) {
085db2c0	75	if (reg->dev && dev_net(reg->dev) == net)
bd3769bf	76	return &reg->dev->nf_hooks_ingress;
e687ad60	77	}
7816ec56	78	#endif
bd3769bf	79	return NULL;
e3b37f11	80	}
7181ebaf	81
085db2c0	82	int nf_register_net_hook(struct net net, const struct nf_hook_ops reg)
0edcf282	83	{
bd3769bf LT	84	struct nf_hook_entry __rcu **pp;
bd3769bf LT	85	struct nf_hook_entry entry, p;
085db2c0	86
7816ec56 AC	87	if (reg->pf == NFPROTO_NETDEV) {
	88	#ifndef CONFIG_NETFILTER_INGRESS
	89	if (reg->hooknum == NF_NETDEV_INGRESS)
	90	return -EOPNOTSUPP;
	91	#endif
	92	if (reg->hooknum != NF_NETDEV_INGRESS \|\|
	93	!reg->dev \|\| dev_net(reg->dev) != net)
	94	return -EINVAL;
	95	}
d4bb5caa	96
bd3769bf LT	97	pp = nf_hook_entry_head(net, reg);
	98	if (!pp)
	99	return -EINVAL;
	100
7181ebaf PNA	101	entry = kmalloc(sizeof(*entry), GFP_KERNEL);
7181ebaf PNA	102	if (!entry)
085db2c0	103	return -ENOMEM;
0edcf282	104
0aa8c57a	105	nf_hook_entry_init(entry, reg);
e3b37f11 AC	106
e3b37f11 AC	107	mutex_lock(&nf_hook_mutex);
085db2c0	108
bd3769bf	109	/* Find the spot in the list */
679972f3	110	for (; (p = nf_entry_dereference(*pp)) != NULL; pp = &p->next) {
0aa8c57a	111	if (reg->priority < nf_hook_entry_priority(p))
bd3769bf	112	break;
f6ebe77f	113	}
bd3769bf LT	114	rcu_assign_pointer(entry->next, p);
bd3769bf LT	115	rcu_assign_pointer(*pp, entry);
e3b37f11	116
fd706d69	117	mutex_unlock(&nf_hook_mutex);
4c091156 EB	118	#ifdef CONFIG_NETFILTER_INGRESS
	119	if (reg->pf == NFPROTO_NETDEV && reg->hooknum == NF_NETDEV_INGRESS)
	120	net_inc_ingress_queue();
	121	#endif
d1c85c2e	122	#ifdef HAVE_JUMP_LABEL
c5905afb	123	static_key_slow_inc(&nf_hooks_needed[reg->pf][reg->hooknum]);
a2d7ec58	124	#endif
f6ebe77f HW	125	return 0;
f6ebe77f HW	126	}
085db2c0	127	EXPORT_SYMBOL(nf_register_net_hook);
f6ebe77f	128
085db2c0	129	void nf_unregister_net_hook(struct net net, const struct nf_hook_ops reg)
f6ebe77f	130	{
bd3769bf LT	131	struct nf_hook_entry __rcu **pp;
	132	struct nf_hook_entry *p;
	133
	134	pp = nf_hook_entry_head(net, reg);
	135	if (WARN_ON_ONCE(!pp))
	136	return;
085db2c0	137
fd706d69	138	mutex_lock(&nf_hook_mutex);
679972f3	139	for (; (p = nf_entry_dereference(*pp)) != NULL; pp = &p->next) {
0aa8c57a	140	if (nf_hook_entry_ops(p) == reg) {
bd3769bf LT	141	rcu_assign_pointer(*pp, p->next);
bd3769bf LT	142	break;
085db2c0 EB	143	}
085db2c0 EB	144	}
fd706d69	145	mutex_unlock(&nf_hook_mutex);
bd3769bf	146	if (!p) {
085db2c0 EB	147	WARN(1, "nf_unregister_net_hook: hook not found!\n");
	148	return;
	149	}
e687ad60	150	#ifdef CONFIG_NETFILTER_INGRESS
4c091156 EB	151	if (reg->pf == NFPROTO_NETDEV && reg->hooknum == NF_NETDEV_INGRESS)
4c091156 EB	152	net_dec_ingress_queue();
e687ad60	153	#endif
d1c85c2e	154	#ifdef HAVE_JUMP_LABEL
c5905afb	155	static_key_slow_dec(&nf_hooks_needed[reg->pf][reg->hooknum]);
a2d7ec58	156	#endif
f6ebe77f	157	synchronize_net();
bd3769bf	158	nf_queue_nf_hook_drop(net, p);
514ed62e FW	159	/* other cpu might still process nfqueue verdict that used reg */
514ed62e FW	160	synchronize_net();
bd3769bf	161	kfree(p);
085db2c0 EB	162	}
	163	EXPORT_SYMBOL(nf_unregister_net_hook);
	164
	165	int nf_register_net_hooks(struct net net, const struct nf_hook_ops reg,
	166	unsigned int n)
	167	{
	168	unsigned int i;
	169	int err = 0;
	170
	171	for (i = 0; i < n; i++) {
	172	err = nf_register_net_hook(net, &reg[i]);
	173	if (err)
	174	goto err;
	175	}
	176	return err;
	177
	178	err:
	179	if (i > 0)
	180	nf_unregister_net_hooks(net, reg, i);
	181	return err;
	182	}
	183	EXPORT_SYMBOL(nf_register_net_hooks);
	184
	185	void nf_unregister_net_hooks(struct net net, const struct nf_hook_ops reg,
	186	unsigned int n)
	187	{
	188	while (n-- > 0)
	189	nf_unregister_net_hook(net, &reg[n]);
	190	}
	191	EXPORT_SYMBOL(nf_unregister_net_hooks);
	192
	193	static LIST_HEAD(nf_hook_list);
	194
e8bffe0c	195	static int _nf_register_hook(struct nf_hook_ops *reg)
085db2c0 EB	196	{
	197	struct net net, last;
	198	int ret;
	199
085db2c0 EB	200	for_each_net(net) {
	201	ret = nf_register_net_hook(net, reg);
	202	if (ret && ret != -ENOENT)
	203	goto rollback;
	204	}
	205	list_add_tail(&reg->list, &nf_hook_list);
085db2c0 EB	206
	207	return 0;
	208	rollback:
	209	last = net;
	210	for_each_net(net) {
	211	if (net == last)
	212	break;
	213	nf_unregister_net_hook(net, reg);
	214	}
e8bffe0c MB	215	return ret;
	216	}
	217
	218	int nf_register_hook(struct nf_hook_ops *reg)
	219	{
	220	int ret;
	221
	222	rtnl_lock();
	223	ret = _nf_register_hook(reg);
085db2c0	224	rtnl_unlock();
e8bffe0c	225
085db2c0 EB	226	return ret;
	227	}
	228	EXPORT_SYMBOL(nf_register_hook);
	229
e8bffe0c	230	static void _nf_unregister_hook(struct nf_hook_ops *reg)
085db2c0 EB	231	{
	232	struct net *net;
	233
085db2c0 EB	234	list_del(&reg->list);
	235	for_each_net(net)
	236	nf_unregister_net_hook(net, reg);
e8bffe0c MB	237	}
	238
	239	void nf_unregister_hook(struct nf_hook_ops *reg)
	240	{
	241	rtnl_lock();
	242	_nf_unregister_hook(reg);
085db2c0	243	rtnl_unlock();
f6ebe77f HW	244	}
	245	EXPORT_SYMBOL(nf_unregister_hook);
	246
972d1cb1 PM	247	int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n)
	248	{
	249	unsigned int i;
	250	int err = 0;
	251
	252	for (i = 0; i < n; i++) {
	253	err = nf_register_hook(&reg[i]);
	254	if (err)
	255	goto err;
	256	}
	257	return err;
	258
	259	err:
	260	if (i > 0)
	261	nf_unregister_hooks(reg, i);
	262	return err;
	263	}
	264	EXPORT_SYMBOL(nf_register_hooks);
	265
e8bffe0c MB	266	/* Caller MUST take rtnl_lock() */
	267	int _nf_register_hooks(struct nf_hook_ops *reg, unsigned int n)
	268	{
	269	unsigned int i;
	270	int err = 0;
	271
	272	for (i = 0; i < n; i++) {
	273	err = _nf_register_hook(&reg[i]);
	274	if (err)
	275	goto err;
	276	}
	277	return err;
	278
	279	err:
	280	if (i > 0)
	281	_nf_unregister_hooks(reg, i);
	282	return err;
	283	}
	284	EXPORT_SYMBOL(_nf_register_hooks);
	285
972d1cb1 PM	286	void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n)
972d1cb1 PM	287	{
f68c5301 CG	288	while (n-- > 0)
f68c5301 CG	289	nf_unregister_hook(&reg[n]);
972d1cb1 PM	290	}
	291	EXPORT_SYMBOL(nf_unregister_hooks);
	292
e8bffe0c MB	293	/* Caller MUST take rtnl_lock */
	294	void _nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n)
	295	{
	296	while (n-- > 0)
	297	_nf_unregister_hook(&reg[n]);
	298	}
	299	EXPORT_SYMBOL(_nf_unregister_hooks);
	300
f6ebe77f	301	/* Returns 1 if okfn() needs to be executed by the caller,
e2361cb9	302	* -EPERM for NF_DROP, 0 otherwise. Caller must hold rcu_read_lock. */
01886bd9 PNA	303	int nf_hook_slow(struct sk_buff skb, struct nf_hook_state state,
01886bd9 PNA	304	struct nf_hook_entry *entry)
f6ebe77f	305	{
f6ebe77f	306	unsigned int verdict;
c63cbc46	307	int ret;
f6ebe77f	308
26dfab72	309	do {
0aa8c57a	310	verdict = nf_hook_entry_hookfn(entry, skb, state);
26dfab72 PNA	311	switch (verdict & NF_VERDICT_MASK) {
	312	case NF_ACCEPT:
	313	entry = rcu_dereference(entry->next);
	314	break;
	315	case NF_DROP:
	316	kfree_skb(skb);
	317	ret = NF_DROP_GETERR(verdict);
	318	if (ret == 0)
	319	ret = -EPERM;
	320	return ret;
26dfab72 PNA	321	case NF_QUEUE:
	322	ret = nf_queue(skb, state, &entry, verdict);
	323	if (ret == 1 && entry)
	324	continue;
	325	return ret;
	326	default:
	327	/* Implicit handling for NF_STOLEN, as well as any other
	328	* non conventional verdicts.
	329	*/
	330	return 0;
	331	}
	332	} while (entry);
	333
	334	return 1;
f6ebe77f HW	335	}
	336	EXPORT_SYMBOL(nf_hook_slow);
	337
	338
37d41879	339	int skb_make_writable(struct sk_buff *skb, unsigned int writable_len)
f6ebe77f	340	{
37d41879	341	if (writable_len > skb->len)
f6ebe77f HW	342	return 0;
	343
	344	/* Not exclusive use of packet? Must copy. */
37d41879 HX	345	if (!skb_cloned(skb)) {
	346	if (writable_len <= skb_headlen(skb))
	347	return 1;
	348	} else if (skb_clone_writable(skb, writable_len))
	349	return 1;
	350
	351	if (writable_len <= skb_headlen(skb))
	352	writable_len = 0;
	353	else
	354	writable_len -= skb_headlen(skb);
	355
	356	return !!__pskb_pull_tail(skb, writable_len);
f6ebe77f HW	357	}
	358	EXPORT_SYMBOL(skb_make_writable);
	359
b7bd1809 PNA	360	/* This needs to be compiled in any case to avoid dependencies between the
	361	* nfnetlink_queue code and nf_conntrack.
	362	*/
a4b4766c KM	363	struct nfnl_ct_hook __rcu *nfnl_ct_hook __read_mostly;
a4b4766c KM	364	EXPORT_SYMBOL_GPL(nfnl_ct_hook);
b7bd1809	365
c0cd1156	366	#if IS_ENABLED(CONFIG_NF_CONNTRACK)
f6ebe77f HW	367	/* This does not belong here, but locally generated errors need it if connection
	368	tracking in use: without this, connection may not be in hash table, and hence
	369	manufactured ICMP or RST packets will not be associated with it. */
312a0c16 PM	370	void (ip_ct_attach)(struct sk_buff , const struct sk_buff *)
312a0c16 PM	371	__rcu __read_mostly;
f6ebe77f HW	372	EXPORT_SYMBOL(ip_ct_attach);
f6ebe77f HW	373
312a0c16	374	void nf_ct_attach(struct sk_buff new, const struct sk_buff skb)
f6ebe77f	375	{
312a0c16	376	void (attach)(struct sk_buff , const struct sk_buff *);
f6ebe77f	377
c3a47ab3 PM	378	if (skb->nfct) {
	379	rcu_read_lock();
	380	attach = rcu_dereference(ip_ct_attach);
	381	if (attach)
	382	attach(new, skb);
	383	rcu_read_unlock();
f6ebe77f HW	384	}
	385	}
	386	EXPORT_SYMBOL(nf_ct_attach);
de6e05c4	387
0e60ebe0	388	void (nf_ct_destroy)(struct nf_conntrack ) __rcu __read_mostly;
de6e05c4 YK	389	EXPORT_SYMBOL(nf_ct_destroy);
	390
	391	void nf_conntrack_destroy(struct nf_conntrack *nfct)
	392	{
	393	void (destroy)(struct nf_conntrack );
	394
	395	rcu_read_lock();
	396	destroy = rcu_dereference(nf_ct_destroy);
	397	BUG_ON(destroy == NULL);
	398	destroy(nfct);
	399	rcu_read_unlock();
	400	}
	401	EXPORT_SYMBOL(nf_conntrack_destroy);
9cb01766	402
62da9865 DB	403	/* Built-in default zone used e.g. by modules. */
	404	const struct nf_conntrack_zone nf_ct_zone_dflt = {
	405	.id = NF_CT_DEFAULT_ZONE_ID,
	406	.dir = NF_CT_DEFAULT_ZONE_DIR,
	407	};
	408	EXPORT_SYMBOL_GPL(nf_ct_zone_dflt);
de6e05c4	409	#endif /* CONFIG_NF_CONNTRACK */
f6ebe77f	410
c7232c99 PM	411	#ifdef CONFIG_NF_NAT_NEEDED
	412	void (nf_nat_decode_session_hook)(struct sk_buff , struct flowi *);
	413	EXPORT_SYMBOL(nf_nat_decode_session_hook);
	414	#endif
	415
085db2c0 EB	416	static int nf_register_hook_list(struct net *net)
	417	{
	418	struct nf_hook_ops *elem;
	419	int ret;
	420
	421	rtnl_lock();
	422	list_for_each_entry(elem, &nf_hook_list, list) {
	423	ret = nf_register_net_hook(net, elem);
	424	if (ret && ret != -ENOENT)
	425	goto out_undo;
	426	}
	427	rtnl_unlock();
	428	return 0;
	429
	430	out_undo:
	431	list_for_each_entry_continue_reverse(elem, &nf_hook_list, list)
	432	nf_unregister_net_hook(net, elem);
	433	rtnl_unlock();
	434	return ret;
	435	}
	436
	437	static void nf_unregister_hook_list(struct net *net)
	438	{
	439	struct nf_hook_ops *elem;
	440
	441	rtnl_lock();
	442	list_for_each_entry(elem, &nf_hook_list, list)
	443	nf_unregister_net_hook(net, elem);
	444	rtnl_unlock();
	445	}
	446
f3c1a44a G	447	static int __net_init netfilter_net_init(struct net *net)
f3c1a44a G	448	{
085db2c0 EB	449	int i, h, ret;
	450
	451	for (i = 0; i < ARRAY_SIZE(net->nf.hooks); i++) {
	452	for (h = 0; h < NF_MAX_HOOKS; h++)
e3b37f11	453	RCU_INIT_POINTER(net->nf.hooks[i][h], NULL);
085db2c0 EB	454	}
085db2c0 EB	455
f3c1a44a G	456	#ifdef CONFIG_PROC_FS
	457	net->nf.proc_netfilter = proc_net_mkdir(net, "netfilter",
	458	net->proc_net);
12202fa7 PNA	459	if (!net->nf.proc_netfilter) {
	460	if (!net_eq(net, &init_net))
	461	pr_err("cannot create netfilter proc entry");
	462
f3c1a44a G	463	return -ENOMEM;
	464	}
	465	#endif
085db2c0 EB	466	ret = nf_register_hook_list(net);
	467	if (ret)
	468	remove_proc_entry("netfilter", net->proc_net);
	469
	470	return ret;
f3c1a44a G	471	}
	472
	473	static void __net_exit netfilter_net_exit(struct net *net)
	474	{
085db2c0	475	nf_unregister_hook_list(net);
f3c1a44a G	476	remove_proc_entry("netfilter", net->proc_net);
	477	}
	478
	479	static struct pernet_operations netfilter_net_ops = {
	480	.init = netfilter_net_init,
	481	.exit = netfilter_net_exit,
	482	};
	483
6d11cfdb	484	int __init netfilter_init(void)
f6ebe77f	485	{
085db2c0	486	int ret;
f6ebe77f	487
6d11cfdb PNA	488	ret = register_pernet_subsys(&netfilter_net_ops);
	489	if (ret < 0)
	490	goto err;
	491
	492	ret = netfilter_log_init();
	493	if (ret < 0)
	494	goto err_pernet;
f6ebe77f	495
6d11cfdb PNA	496	return 0;
	497	err_pernet:
	498	unregister_pernet_subsys(&netfilter_net_ops);
	499	err:
	500	return ret;
f6ebe77f	501	}