FreeBSD/Linux Kernel Cross Reference
sys/net/pfil.h

     /*      $NetBSD: pfil.h,v 1.29 2008/05/29 14:51:27 mrg 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.
     *
     * 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_
    
    #ifdef _KERNEL_OPT
    #include "opt_pfil_hooks.h"
    #endif
    
    #include <sys/queue.h>
    #include <net/dlt.h>
    #include <sys/null.h>
    
    struct mbuf;
    struct ifnet;
    
    /*
     * 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);
            void    *pfil_arg;
            int     pfil_flags;
    };
    
    #define PFIL_IN         0x00000001
    #define PFIL_OUT        0x00000002
    #define PFIL_ALL        (PFIL_IN|PFIL_OUT)
    #define PFIL_WAITOK     0x00000004
    #define PFIL_IFADDR     0x00000008
    #define PFIL_IFNET      0x00000010
    
    /* events notified by PFIL_IFNET */
    #define PFIL_IFNET_ATTACH       0
    #define PFIL_IFNET_DETACH       1
    
    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;
            pfil_list_t     ph_ifaddr;
            pfil_list_t     ph_ifnetevent; /* XXX naming collision */
            int             ph_type;
            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;
    };
    typedef struct pfil_head pfil_head_t;
    
    #ifdef _KERNEL
    
    int     pfil_run_hooks(struct pfil_head *, struct mbuf **, struct ifnet *,
                int);
    
    int     pfil_add_hook(int (*func)(void *, struct mbuf **,
                struct ifnet *, int), void *, int, struct pfil_head *);
    int     pfil_remove_hook(int (*func)(void *, struct mbuf **,
                struct ifnet *, int), void *, int, struct pfil_head *);
    
    int     pfil_head_register(struct pfil_head *);
    int     pfil_head_unregister(struct pfil_head *);
    
    struct pfil_head *pfil_head_get(int, u_long);
   
   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 if (dir == PFIL_IFADDR)
                   return (TAILQ_FIRST(&ph->ph_ifaddr));
           else if (dir == PFIL_IFNET)
                   return (TAILQ_FIRST(&ph->ph_ifnetevent));
           else
                   return (NULL);
   }
   
   #endif /* _KERNEL */
   
   /* XXX */
   #if defined(_KERNEL_OPT)
   #include "ipfilter.h"
   #endif
   
   #if NIPFILTER > 0
   #ifdef PFIL_HOOKS
   #undef PFIL_HOOKS
   #endif
   #define PFIL_HOOKS
   #endif /* NIPFILTER */
   
   #ifdef _KERNEL
   /* in sys/net/if.c */
   extern struct pfil_head if_pfil; /* packet filtering hook for interfaces */
   #endif /* _KERNEL */
   
   #endif /* !_NET_PFIL_H_ */

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