path: root/include/linux/netfilter.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __LINUX_NETFILTER_H
#define __LINUX_NETFILTER_H

#include <linux/init.h>
#include <linux/skbuff.h>
#include <linux/net.h>
#include <linux/if.h>
#include <linux/in.h>
#include <linux/in6.h>
#include <linux/wait.h>
#include <linux/list.h>
#include <linux/static_key.h>
#include <linux/netfilter_defs.h>
#include <linux/netdevice.h>
#include <net/net_namespace.h>

static inline int NF_DROP_GETERR(int verdict)
{
	return -(verdict >> NF_VERDICT_QBITS);
}

static inline int nf_inet_addr_cmp(const union nf_inet_addr *a1,
				   const union nf_inet_addr *a2)
{
#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
	const unsigned long *ul1 = (const unsigned long *)a1;
	const unsigned long *ul2 = (const unsigned long *)a2;

	return ((ul1[0] ^ ul2[0]) | (ul1[1] ^ ul2[1])) == 0UL;
#else
	return a1->all[0] == a2->all[0] &&
	       a1->all[1] == a2->all[1] &&
	       a1->all[2] == a2->all[2] &&
	       a1->all[3] == a2->all[3];
#endif
}

static inline void nf_inet_addr_mask(const union nf_inet_addr *a1,
				     union nf_inet_addr *result,
				     const union nf_inet_addr *mask)
{
#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
	const unsigned long *ua = (const unsigned long *)a1;
	unsigned long *ur = (unsigned long *)result;
	const unsigned long *um = (const unsigned long *)mask;

	ur[0] = ua[0] & um[0];
	ur[1] = ua[1] & um[1];
#else
	result->all[0] = a1->all[0] & mask->all[0];
	result->all[1] = a1->all[1] & mask->all[1];
	result->all[2] = a1->all[2] & mask->all[2];
	result->all[3] = a1->all[3] & mask->all[3];
#endif
}

int netfilter_init(void);

struct sk_buff;

struct nf_hook_ops;

struct sock;

struct nf_hook_state {
	unsigned int hook;
	u_int8_t pf;
	struct net_device *in;
	struct net_device *out;
	struct sock *sk;
	struct net *net;
	int (*okfn)(struct net *, struct sock *, struct sk_buff *);
};

typedef unsigned int nf_hookfn(void *priv,
			       struct sk_buff *skb,
			       const struct nf_hook_state *state);
struct nf_hook_ops {
	/* User fills in from here down. */
	nf_hookfn		*hook;
	struct net_device	*dev;
	void			*priv;
	u_int8_t		pf;
	unsigned int		hooknum;
	/* Hooks are ordered in ascending priority. */
	int			priority;
};

struct nf_hook_entry {
	nf_hookfn			*hook;
	void				*priv;
};

struct nf_hook_entries_rcu_head {
	struct rcu_head head;
	void	*allocation;
};

struct nf_hook_entries {
	u16				num_hook_entries;
	/* padding */
	struct nf_hook_entry		hooks[];

	/* trailer: pointers to original orig_ops of each hook,
	 * followed by rcu_head and scratch space used for freeing
	 * the structure via call_rcu.
	 *
	 *   This is not part of struct nf_hook_entry since its only
	 *   needed in slow path (hook register/unregister):
	 * const struct nf_hook_ops     *orig_ops[]
	 *
	 *   For the same reason, we store this at end -- its
	 *   only needed when a hook is deleted, not during
	 *   packet path processing:
	 * struct nf_hook_entries_rcu_head     head
	 */
};

#ifdef CONFIG_NETFILTER
static inline struct nf_hook_ops **nf_hook_entries_get_hook_ops(const struct nf_hook_entries *e)
{
	unsigned int n = e->num_hook_entries;
	const void *hook_end;

	hook_end = &e->hooks[n]; /* this is *past* ->hooks[]! */

	return (struct nf_hook_ops **)hook_end;
}

static inline int
nf_hook_entry_hookfn(const struct nf_hook_entry *entry, struct sk_buff *skb,
		     struct nf_hook_state *state)
{
	return entry->hook(entry->priv, skb, state);
}

static inline void nf_hook_state_init(struct nf_hook_state *p,
				      unsigned int hook,
				      u_int8_t pf,
				      struct net_device *indev,
				      struct net_device *outdev,
				      struct sock *sk,
				      struct net *net,
				      int (*okfn)(struct net *, struct sock *, struct sk_buff *))
{
	p->hook = hook;
	p->pf = pf;
	p->in = indev;
	p->out = outdev;
	p->sk = sk;
	p->net = net;
	p->okfn = okfn;
}



struct nf_sockopt_ops {
	struct list_head list;

	u_int8_t pf;

	/* Non-inclusive ranges: use 0/0/NULL to never get called. */
	int set_optmin;
	int set_optmax;
	int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len);
	int get_optmin;
	int get_optmax;
	int (*get)(struct sock *sk, int optval, void __user *user, int *len);
	/* Use the module struct to lock set/get code in place */
	struct module *owner;
};

/* Function to register/unregister hook points. */
int nf_register_net_hook(struct net *net, const struct nf_hook_ops *ops);
void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *ops);
int nf_register_net_hooks(struct net *net, const struct nf_hook_ops *reg,
			  unsigned int n);
void nf_unregister_net_hooks(struct net *net, const struct nf_hook_ops *reg,
			     unsigned int n);

/* Functions to register get/setsockopt ranges (non-inclusive).  You
   need to check permissions yourself! */
int nf_register_sockopt(struct nf_sockopt_ops *reg);
void nf_unregister_sockopt(struct nf_sockopt_ops *reg);

#ifdef CONFIG_JUMP_LABEL
extern struct static_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
#endif

int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state,
		 const struct nf_hook_entries *e, unsigned int i);

void nf_hook_slow_list(struct list_head *head, struct nf_hook_state *state,
		       const struct nf_hook_entries *e);
/**
 *	nf_hook - call a netfilter hook
 *
 *	Returns 1 if the hook has allowed the packet to pass.  The function
 *	okfn must be invoked by the caller in this case.  Any other return
 *	value indicates the packet has been consumed by the hook.
 */
static inline int nf_hook(u_int8_t pf, unsigned int hook, struct net *net,
			  struct sock *sk, struct sk_buff *skb,
			  struct net_device *indev, struct net_device *outdev,
			  int (*okfn)(struct net *, struct sock *, struct sk_buff *))
{
	struct nf_hook_entries *hook_head = NULL;
	int ret = 1;

#ifdef CONFIG_JUMP_LABEL
	if (__builtin_constant_p(pf) &&
	    __builtin_constant_p(hook) &&
	    !static_key_false(&nf_hooks_needed[pf][hook]))
		ret