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

     /*      $FreeBSD$ */
     /*      $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>
    #include <net/vnet.h>
    
    struct mbuf;
    struct ifnet;
    struct inpcb;
    
    typedef int     (*pfil_func_t)(void *, struct mbuf **, struct ifnet *, int,
                        struct inpcb *);
    typedef int     (*pfil_func_flags_t)(void *, struct mbuf **, struct ifnet *,
                        int, int, struct inpcb *);
    
    /*
     * The packet filter hooks are designed for anything to call them to
     * possibly intercept the packet.  Multiple filter hooks are chained
     * together and after each other in the specified order.
     */
    struct packet_filter_hook {
            TAILQ_ENTRY(packet_filter_hook) pfil_chain;
            pfil_func_t              pfil_func;
            pfil_func_flags_t        pfil_func_flags;
            void                    *pfil_arg;
    };
    
    #define PFIL_IN         0x00000001
    #define PFIL_OUT        0x00000002
    #define PFIL_WAITOK     0x00000004
    #define PFIL_FWD        0x00000008
    #define PFIL_ALL        (PFIL_IN|PFIL_OUT)
    
    typedef TAILQ_HEAD(pfil_chain, packet_filter_hook) pfil_chain_t;
    
    #define PFIL_TYPE_AF            1       /* key is AF_* type */
    #define PFIL_TYPE_IFNET         2       /* key is ifnet pointer */
    
    #define PFIL_FLAG_PRIVATE_LOCK  0x01    /* Personal lock instead of global */
    
    /*
     * A pfil head is created by each protocol or packet intercept point.
     * For packet is then run through the hook chain for inspection.
     */
    struct pfil_head {
            pfil_chain_t     ph_in;
            pfil_chain_t     ph_out;
            int              ph_type;
            int              ph_nhooks;
    #if defined( __linux__ ) || defined( _WIN32 )
            rwlock_t         ph_mtx;
    #else
            struct rmlock   *ph_plock;      /* Pointer to the used lock */
            struct rmlock    ph_lock;       /* Private lock storage */
            int              flags;
    #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;
   };
   
   VNET_DECLARE(struct rmlock, pfil_lock);
   #define V_pfil_lock     VNET(pfil_lock)
   
   /* Public functions for pfil hook management by packet filters. */
   struct pfil_head *pfil_head_get(int, u_long);
   int     pfil_add_hook_flags(pfil_func_flags_t, void *, int, struct pfil_head *);
   int     pfil_add_hook(pfil_func_t, void *, int, struct pfil_head *);
   int     pfil_remove_hook_flags(pfil_func_flags_t, void *, int, struct pfil_head *);
   int     pfil_remove_hook(pfil_func_t, void *, int, struct pfil_head *);
   #define PFIL_HOOKED(p) ((p)->ph_nhooks > 0)
   
   /* Public functions to run the packet inspection by protocols. */
   int     pfil_run_hooks(struct pfil_head *, struct mbuf **, struct ifnet *, int,
       int, struct inpcb *inp);
   
   /* Public functions for pfil head management by protocols. */
   int     pfil_head_register(struct pfil_head *);
   int     pfil_head_unregister(struct pfil_head *);
   
   /* Public pfil locking functions for self managed locks by packet filters. */
   int     pfil_try_rlock(struct pfil_head *, struct rm_priotracker *);
   void    pfil_rlock(struct pfil_head *, struct rm_priotracker *);
   void    pfil_runlock(struct pfil_head *, struct rm_priotracker *);
   void    pfil_wlock(struct pfil_head *);
   void    pfil_wunlock(struct pfil_head *);
   int     pfil_wowned(struct pfil_head *ph);
   
   #endif /* _NET_PFIL_H_ */

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