/*	$FreeBSD: src/sys/net/pfil.h,v 1.16 2007/06/08 12:43:25 gallatin Exp $ */
/*	$NetBSD: pfil.h,v 1.22 2003/06/23 12:57:08 martin Exp $	*/

/*-
 * Copyright (c) 1996 Matthew R. Green
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef _NET_PFIL_H_
#define _NET_PFIL_H_

#include <sys/systm.h>
#include <sys/queue.h>
#include <sys/_lock.h>
#include <sys/_mutex.h>
#include <sys/lock.h>
#include <sys/rmlock.h>

struct mbuf;
struct ifnet;
struct inpcb;

/*
 * The packet filter hooks are designed for anything to call them to
 * possibly intercept the packet.
 */
struct packet_filter_hook {
        TAILQ_ENTRY(packet_filter_hook) pfil_link;
	int	(*pfil_func)(void *, struct mbuf **, struct ifnet *, int,
		    struct inpcb *);
	void	*pfil_arg;
};

#define PFIL_IN		0x00000001
#define PFIL_OUT	0x00000002
#define PFIL_WAITOK	0x00000004
#define PFIL_ALL	(PFIL_IN|PFIL_OUT)

typedef	TAILQ_HEAD(pfil_list, packet_filter_hook) pfil_list_t;

#define	PFIL_TYPE_AF		1	/* key is AF_* type */
#define	PFIL_TYPE_IFNET		2	/* key is ifnet pointer */

struct pfil_head {
	pfil_list_t	ph_in;
	pfil_list_t	ph_out;
	int		ph_type;
	int		ph_nhooks;
#if defined( __linux__ ) || defined( _WIN32 )
	rwlock_t	ph_mtx;
#else
	struct rmlock	ph_lock;
#endif
	union {
		u_long		phu_val;
		void		*phu_ptr;
	} ph_un;
#define	ph_af		ph_un.phu_val
#define	ph_ifnet	ph_un.phu_ptr
	LIST_ENTRY(pfil_head) ph_list;
};

int	pfil_add_hook(int (*func)(void *, struct mbuf **, struct ifnet *,
	    int, struct inpcb *), void *, int, struct pfil_head *);
int	pfil_remove_hook(int (*func)(void *, struct mbuf **, struct ifnet *,
	    int, struct inpcb *), void *, int, struct pfil_head *);
int	pfil_run_hooks(struct pfil_head *, struct mbuf **, struct ifnet *,
	    int, struct inpcb *inp);

int	pfil_head_register(struct pfil_head *);
int	pfil_head_unregister(struct pfil_head *);

struct pfil_head *pfil_head_get(int, u_long);

#define	PFIL_HOOKED(p) ((p)->ph_nhooks > 0)
#define	PFIL_LOCK_INIT(p) \
    rm_init_flags(&(p)->ph_lock, "PFil hook read/write mutex", RM_RECURSE)
#define	PFIL_LOCK_DESTROY(p) rm_destroy(&(p)->ph_lock)
#define PFIL_RLOCK(p, t) rm_rlock(&(p)->ph_lock, (t))
#define PFIL_WLOCK(p) rm_wlock(&(p)->ph_lock)
#define PFIL_RUNLOCK(p, t) rm_runlock(&(p)->ph_lock, (t))
#define PFIL_WUNLOCK(p) rm_wunlock(&(p)->ph_lock)
#define PFIL_LIST_LOCK() mtx_lock(&pfil_global_lock)
#define PFIL_LIST_UNLOCK() mtx_unlock(&pfil_global_lock)

static __inline struct packet_filter_hook *
pfil_hook_get(int dir, struct pfil_head *ph)
{

	if (dir == PFIL_IN)
		return (TAILQ_FIRST(&ph->ph_in));
	else if (dir == PFIL_OUT)
		return (TAILQ_FIRST(&ph->ph_out));
	else
		return (NULL);
}

#endif /* _NET_PFIL_H_ */
