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#ifndef __LINUX_NETFILTER_H

#define __LINUX_NETFILTER_H

#ifdef __KERNEL__

#include <linux/init.h>

#include <linux/types.h>

#include <linux/skbuff.h>

#include <linux/net.h>

#include <linux/if.h>

#include <linux/wait.h>

#include <linux/list.h>

#endif

/* Responses from hook functions. */

#define NF_DROP 0

#define NF_ACCEPT 1

#define NF_STOLEN 2

#define NF_QUEUE 3

#define NF_REPEAT 4

#define NF_MAX_VERDICT NF_REPEAT

/* Generic cache responses from hook functions.

   <= 0x2000 is used for protocol-flags. */

#define NFC_UNKNOWN 0x4000

#define NFC_ALTERED 0x8000

#ifdef __KERNEL__

#include <linux/config.h>

#ifdef CONFIG_NETFILTER

extern void netfilter_init(void);

/* Largest hook number + 1 */

#define NF_MAX_HOOKS 8

struct sk_buff;

struct net_device;

typedef unsigned int nf_hookfn(unsigned int hooknum,

                               struct sk_buff **skb,

                               const struct net_device *in,

                               const struct net_device *out,

                               int (*okfn)(struct sk_buff *));

struct nf_hook_ops

{

        struct list_head list;

        /* User fills in from here down. */

        nf_hookfn *hook;

        int pf;

        int hooknum;

        /* Hooks are ordered in ascending priority. */

        int priority;

};

struct nf_sockopt_ops

{

        struct list_head list;

        int 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, unsigned int len);

        int get_optmin;

        int get_optmax;

        int (*get)(struct sock *sk, int optval, void *user, int *len);

        /* Number of users inside set() or get(). */

        unsigned int use;

        struct task_struct *cleanup_task;

};

/* Each queued (to userspace) skbuff has one of these. */

struct nf_info

{

        /* The ops struct which sent us to userspace. */

        struct nf_hook_ops *elem;

        /* If we're sent to userspace, this keeps housekeeping info */

        int pf;

        unsigned int hook;

        struct net_device *indev, *outdev;

        int (*okfn)(struct sk_buff *);

};

/* Function to register/unregister hook points. */

int nf_register_hook(struct nf_hook_ops *reg);

void nf_unregister_hook(struct nf_hook_ops *reg);

/* 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);

extern struct list_head nf_hooks[NPROTO][NF_MAX_HOOKS];

/* Activate hook; either okfn or kfree_skb called, unless a hook

   returns NF_STOLEN (in which case, it's up to the hook to deal with

   the consequences).

   Returns -ERRNO if packet dropped.  Zero means queued, stolen or

   accepted.

*/

/* RR:

   > I don't want nf_hook to return anything because people might forget

   > about async and trust the return value to mean "packet was ok".

   AK:

   Just document it clearly, then you can expect some sense from kernel

   coders :)

*/

/* This is gross, but inline doesn't cut it for avoiding the function

   call in fast path: gcc doesn't inline (needs value tracking?). --RR */

#ifdef CONFIG_NETFILTER_DEBUG

#define NF_HOOK nf_hook_slow

#else

#define NF_HOOK(pf, hook, skb, indev, outdev, okfn)                     \

(list_empty(&nf_hooks[(pf)][(hook)])                                    \

 ? (okfn)(skb)                                                          \

 : nf_hook_slow((pf), (hook), (skb), (indev), (outdev), (okfn)))

#endif

int nf_hook_slow(int pf, unsigned int hook, struct sk_buff *skb,

                 struct net_device *indev, struct net_device *outdev,

                 int (*okfn)(struct sk_buff *));

/* Call setsockopt() */

int nf_setsockopt(struct sock *sk, int pf, int optval, char *opt,

                  int len);

int nf_getsockopt(struct sock *sk, int pf, int optval, char *opt,

                  int *len);

/* Packet queuing */

typedef int (*nf_queue_outfn_t)(struct sk_buff *skb,

                                struct nf_info *info, void *data);

extern int nf_register_queue_handler(int pf,

                                     nf_queue_outfn_t outfn, void *data);

extern int nf_unregister_queue_handler(int pf);

extern void nf_reinject(struct sk_buff *skb,

                        struct nf_info *info,

                        unsigned int verdict);

extern void (*ip_ct_attach)(struct sk_buff *, struct nf_ct_info *);

#ifdef CONFIG_NETFILTER_DEBUG

extern void nf_dump_skb(int pf, struct sk_buff *skb);

#endif

/* FIXME: Before cache is ever used, this must be implemented for real. */

extern void nf_invalidate_cache(int pf);

#else /* !CONFIG_NETFILTER */

#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb)

#endif /*CONFIG_NETFILTER*/

/* From arch/i386/kernel/smp.c:

 *

 *      Why isn't this somewhere standard ??

 *

 * Maybe because this procedure is horribly buggy, and does

 * not deserve to live.  Think about signedness issues for five

 * seconds to see why.          - Linus

 */

/* Two signed, return a signed. */

#define SMAX(a,b) ((ssize_t)(a)>(ssize_t)(b) ? (ssize_t)(a) : (ssize_t)(b))

#define SMIN(a,b) ((ssize_t)(a)<(ssize_t)(b) ? (ssize_t)(a) : (ssize_t)(b))

/* Two unsigned, return an unsigned. */

#define UMAX(a,b) ((size_t)(a)>(size_t)(b) ? (size_t)(a) : (size_t)(b))

#define UMIN(a,b) ((size_t)(a)<(size_t)(b) ? (size_t)(a) : (size_t)(b))

/* Two unsigned, return a signed. */

#define SUMAX(a,b) ((size_t)(a)>(size_t)(b) ? (ssize_t)(a) : (ssize_t)(b))

#define SUMIN(a,b) ((size_t)(a)<(size_t)(b) ? (ssize_t)(a) : (ssize_t)(b))

#endif /*__KERNEL__*/

#endif /*__LINUX_NETFILTER_H*/