[mirror_ubuntu-artful-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);

static struct nf_hook_entry *
__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 NULL;

	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 NULL;
	}
#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

	return p;
}

void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *reg)
{
	struct nf_hook_entry *p = __nf_unregister_net_hook(net, reg);
	unsigned int nfq;

	if (!p)
		return;

	synchronize_net();

	/* other cpu might still process nfqueue verdict that used reg */
	nfq = nf_queue_nf_hook_drop(net);
	if (nfq)
		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 hookcount)
{
	struct nf_hook_entry *to_free[16];
	unsigned int i, n, nfq;

	do {
		n = min_t(unsigned int, hookcount, ARRAY_SIZE(to_free));

		for (i = 0; i < n; i++)
			to_free[i] = __nf_unregister_net_hook(net, &reg[i]);

		synchronize_net();

		/* need 2nd synchronize_net() if nfqueue is used, skb
		 * can get reinjected right before nf_queue_hook_drop()
		 */
		nfq = nf_queue_nf_hook_drop(net);
		if (nfq)
			synchronize_net();

		for (i = 0; i < n; i++)
			kfree(to_free[i]);

		reg += n;
		hookcount -= n;
	} while (hookcount > 0);
}
EXPORT_SYMBOL(nf_unregister_net_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 __net_init netfilter_net_init(struct net *net)
{
	int i, h;

	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

	return 0;
}

static void __net_exit netfilter_net_exit(struct net *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
933bd83e FW	129	static struct nf_hook_entry *
933bd83e FW	130	__nf_unregister_net_hook(struct net net, const struct nf_hook_ops reg)
f6ebe77f	131	{
bd3769bf LT	132	struct nf_hook_entry __rcu **pp;
	133	struct nf_hook_entry *p;
	134
	135	pp = nf_hook_entry_head(net, reg);
	136	if (WARN_ON_ONCE(!pp))
933bd83e	137	return NULL;
085db2c0	138
fd706d69	139	mutex_lock(&nf_hook_mutex);
679972f3	140	for (; (p = nf_entry_dereference(*pp)) != NULL; pp = &p->next) {
0aa8c57a	141	if (nf_hook_entry_ops(p) == reg) {
bd3769bf LT	142	rcu_assign_pointer(*pp, p->next);
bd3769bf LT	143	break;
085db2c0 EB	144	}
085db2c0 EB	145	}
fd706d69	146	mutex_unlock(&nf_hook_mutex);
bd3769bf	147	if (!p) {
085db2c0	148	WARN(1, "nf_unregister_net_hook: hook not found!\n");
933bd83e	149	return NULL;
085db2c0	150	}
e687ad60	151	#ifdef CONFIG_NETFILTER_INGRESS
4c091156 EB	152	if (reg->pf == NFPROTO_NETDEV && reg->hooknum == NF_NETDEV_INGRESS)
4c091156 EB	153	net_dec_ingress_queue();
e687ad60	154	#endif
d1c85c2e	155	#ifdef HAVE_JUMP_LABEL
c5905afb	156	static_key_slow_dec(&nf_hooks_needed[reg->pf][reg->hooknum]);
a2d7ec58	157	#endif
933bd83e FW	158
	159	return p;
	160	}
	161
	162	void nf_unregister_net_hook(struct net net, const struct nf_hook_ops reg)
	163	{
	164	struct nf_hook_entry *p = __nf_unregister_net_hook(net, reg);
039b40ee	165	unsigned int nfq;
933bd83e FW	166
	167	if (!p)
	168	return;
	169
f6ebe77f	170	synchronize_net();
039b40ee	171
514ed62e	172	/* other cpu might still process nfqueue verdict that used reg */
039b40ee FW	173	nfq = nf_queue_nf_hook_drop(net);
	174	if (nfq)
	175	synchronize_net();
bd3769bf	176	kfree(p);
085db2c0 EB	177	}
	178	EXPORT_SYMBOL(nf_unregister_net_hook);
	179
	180	int nf_register_net_hooks(struct net net, const struct nf_hook_ops reg,
	181	unsigned int n)
	182	{
	183	unsigned int i;
	184	int err = 0;
	185
	186	for (i = 0; i < n; i++) {
	187	err = nf_register_net_hook(net, &reg[i]);
	188	if (err)
	189	goto err;
	190	}
	191	return err;
	192
	193	err:
	194	if (i > 0)
	195	nf_unregister_net_hooks(net, reg, i);
	196	return err;
	197	}
	198	EXPORT_SYMBOL(nf_register_net_hooks);
	199
	200	void nf_unregister_net_hooks(struct net net, const struct nf_hook_ops reg,
933bd83e	201	unsigned int hookcount)
085db2c0	202	{
933bd83e	203	struct nf_hook_entry *to_free[16];
039b40ee	204	unsigned int i, n, nfq;
933bd83e FW	205
	206	do {
	207	n = min_t(unsigned int, hookcount, ARRAY_SIZE(to_free));
	208
	209	for (i = 0; i < n; i++)
	210	to_free[i] = __nf_unregister_net_hook(net, &reg[i]);
	211
	212	synchronize_net();
	213
039b40ee FW	214	/* need 2nd synchronize_net() if nfqueue is used, skb
	215	* can get reinjected right before nf_queue_hook_drop()
	216	*/
	217	nfq = nf_queue_nf_hook_drop(net);
	218	if (nfq)
	219	synchronize_net();
933bd83e FW	220
	221	for (i = 0; i < n; i++)
	222	kfree(to_free[i]);
	223
	224	reg += n;
	225	hookcount -= n;
	226	} while (hookcount > 0);
085db2c0 EB	227	}
	228	EXPORT_SYMBOL(nf_unregister_net_hooks);
	229
f6ebe77f	230	/* Returns 1 if okfn() needs to be executed by the caller,
e2361cb9	231	* -EPERM for NF_DROP, 0 otherwise. Caller must hold rcu_read_lock. */
01886bd9 PNA	232	int nf_hook_slow(struct sk_buff skb, struct nf_hook_state state,
01886bd9 PNA	233	struct nf_hook_entry *entry)
f6ebe77f	234	{
f6ebe77f	235	unsigned int verdict;
c63cbc46	236	int ret;
f6ebe77f	237
26dfab72	238	do {
0aa8c57a	239	verdict = nf_hook_entry_hookfn(entry, skb, state);
26dfab72 PNA	240	switch (verdict & NF_VERDICT_MASK) {
	241	case NF_ACCEPT:
	242	entry = rcu_dereference(entry->next);
	243	break;
	244	case NF_DROP:
	245	kfree_skb(skb);
	246	ret = NF_DROP_GETERR(verdict);
	247	if (ret == 0)
	248	ret = -EPERM;
	249	return ret;
26dfab72 PNA	250	case NF_QUEUE:
	251	ret = nf_queue(skb, state, &entry, verdict);
	252	if (ret == 1 && entry)
	253	continue;
	254	return ret;
	255	default:
	256	/* Implicit handling for NF_STOLEN, as well as any other
	257	* non conventional verdicts.
	258	*/
	259	return 0;
	260	}
	261	} while (entry);
	262
	263	return 1;
f6ebe77f HW	264	}
	265	EXPORT_SYMBOL(nf_hook_slow);
	266
	267
37d41879	268	int skb_make_writable(struct sk_buff *skb, unsigned int writable_len)
f6ebe77f	269	{
37d41879	270	if (writable_len > skb->len)
f6ebe77f HW	271	return 0;
	272
	273	/* Not exclusive use of packet? Must copy. */
37d41879 HX	274	if (!skb_cloned(skb)) {
	275	if (writable_len <= skb_headlen(skb))
	276	return 1;
	277	} else if (skb_clone_writable(skb, writable_len))
	278	return 1;
	279
	280	if (writable_len <= skb_headlen(skb))
	281	writable_len = 0;
	282	else
	283	writable_len -= skb_headlen(skb);
	284
	285	return !!__pskb_pull_tail(skb, writable_len);
f6ebe77f HW	286	}
	287	EXPORT_SYMBOL(skb_make_writable);
	288
b7bd1809 PNA	289	/* This needs to be compiled in any case to avoid dependencies between the
	290	* nfnetlink_queue code and nf_conntrack.
	291	*/
a4b4766c KM	292	struct nfnl_ct_hook __rcu *nfnl_ct_hook __read_mostly;
a4b4766c KM	293	EXPORT_SYMBOL_GPL(nfnl_ct_hook);
b7bd1809	294
c0cd1156	295	#if IS_ENABLED(CONFIG_NF_CONNTRACK)
f6ebe77f HW	296	/* This does not belong here, but locally generated errors need it if connection
	297	tracking in use: without this, connection may not be in hash table, and hence
	298	manufactured ICMP or RST packets will not be associated with it. */
312a0c16 PM	299	void (ip_ct_attach)(struct sk_buff , const struct sk_buff *)
312a0c16 PM	300	__rcu __read_mostly;
f6ebe77f HW	301	EXPORT_SYMBOL(ip_ct_attach);
f6ebe77f HW	302
312a0c16	303	void nf_ct_attach(struct sk_buff new, const struct sk_buff skb)
f6ebe77f	304	{
312a0c16	305	void (attach)(struct sk_buff , const struct sk_buff *);
f6ebe77f	306
a9e419dc	307	if (skb->_nfct) {
c3a47ab3 PM	308	rcu_read_lock();
	309	attach = rcu_dereference(ip_ct_attach);
	310	if (attach)
	311	attach(new, skb);
	312	rcu_read_unlock();
f6ebe77f HW	313	}
	314	}
	315	EXPORT_SYMBOL(nf_ct_attach);
de6e05c4	316
0e60ebe0	317	void (nf_ct_destroy)(struct nf_conntrack ) __rcu __read_mostly;
de6e05c4 YK	318	EXPORT_SYMBOL(nf_ct_destroy);
	319
	320	void nf_conntrack_destroy(struct nf_conntrack *nfct)
	321	{
	322	void (destroy)(struct nf_conntrack );
	323
	324	rcu_read_lock();
	325	destroy = rcu_dereference(nf_ct_destroy);
	326	BUG_ON(destroy == NULL);
	327	destroy(nfct);
	328	rcu_read_unlock();
	329	}
	330	EXPORT_SYMBOL(nf_conntrack_destroy);
9cb01766	331
62da9865 DB	332	/* Built-in default zone used e.g. by modules. */
	333	const struct nf_conntrack_zone nf_ct_zone_dflt = {
	334	.id = NF_CT_DEFAULT_ZONE_ID,
	335	.dir = NF_CT_DEFAULT_ZONE_DIR,
	336	};
	337	EXPORT_SYMBOL_GPL(nf_ct_zone_dflt);
de6e05c4	338	#endif /* CONFIG_NF_CONNTRACK */
f6ebe77f	339
c7232c99 PM	340	#ifdef CONFIG_NF_NAT_NEEDED
	341	void (nf_nat_decode_session_hook)(struct sk_buff , struct flowi *);
	342	EXPORT_SYMBOL(nf_nat_decode_session_hook);
	343	#endif
	344
f3c1a44a G	345	static int __net_init netfilter_net_init(struct net *net)
f3c1a44a G	346	{
073dd5ad	347	int i, h;
085db2c0 EB	348
	349	for (i = 0; i < ARRAY_SIZE(net->nf.hooks); i++) {
	350	for (h = 0; h < NF_MAX_HOOKS; h++)
e3b37f11	351	RCU_INIT_POINTER(net->nf.hooks[i][h], NULL);
085db2c0 EB	352	}
085db2c0 EB	353
f3c1a44a G	354	#ifdef CONFIG_PROC_FS
	355	net->nf.proc_netfilter = proc_net_mkdir(net, "netfilter",
	356	net->proc_net);
12202fa7 PNA	357	if (!net->nf.proc_netfilter) {
	358	if (!net_eq(net, &init_net))
	359	pr_err("cannot create netfilter proc entry");
	360
f3c1a44a G	361	return -ENOMEM;
	362	}
	363	#endif
085db2c0	364
073dd5ad	365	return 0;
f3c1a44a G	366	}
	367
	368	static void __net_exit netfilter_net_exit(struct net *net)
	369	{
	370	remove_proc_entry("netfilter", net->proc_net);
	371	}
	372
	373	static struct pernet_operations netfilter_net_ops = {
	374	.init = netfilter_net_init,
	375	.exit = netfilter_net_exit,
	376	};
	377
6d11cfdb	378	int __init netfilter_init(void)
f6ebe77f	379	{
085db2c0	380	int ret;
f6ebe77f	381
6d11cfdb PNA	382	ret = register_pernet_subsys(&netfilter_net_ops);
	383	if (ret < 0)
	384	goto err;
	385
	386	ret = netfilter_log_init();
	387	if (ret < 0)
	388	goto err_pernet;
f6ebe77f	389
6d11cfdb PNA	390	return 0;
	391	err_pernet:
	392	unregister_pernet_subsys(&netfilter_net_ops);
	393	err:
	394	return ret;
f6ebe77f	395	}