NetBSD/sys/net/pfil.c

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/* $NetBSD: pfil.c,v 1.9 1999/10/10 09:07:32 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.
* 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.
*/
#include <sys/param.h>
#include <sys/errno.h>
#include <sys/malloc.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/queue.h>
#include <net/if.h>
#include <net/pfil.h>
typedef TAILQ_HEAD(, packet_filter_hook) pfil_list_t;
pfil_list_t pfil_in_list;
pfil_list_t pfil_out_list;
static int done_pfil_init;
static void pfil_init __P((void));
static void pfil_list_add(pfil_list_t *,
int (*) __P((void *, int, struct ifnet *, int, struct mbuf **)), int);
static void pfil_list_remove(pfil_list_t *,
int (*) __P((void *, int, struct ifnet *, int, struct mbuf **)));
static void
pfil_init()
{
TAILQ_INIT(&pfil_in_list);
TAILQ_INIT(&pfil_out_list);
done_pfil_init = 1;
}
/*
* pfil_add_hook() adds a function to the packet filter hook. the
* flags are:
* PFIL_IN call me on incoming packets
* PFIL_OUT call me on outgoing packets
* PFIL_ALL call me on all of the above
* PFIL_WAITOK OK to call malloc with M_WAITOK.
*/
void
pfil_add_hook(func, flags)
int (*func) __P((void *, int, struct ifnet *, int,
struct mbuf **));
int flags;
{
if (done_pfil_init == 0)
pfil_init();
if (flags & PFIL_IN)
pfil_list_add(&pfil_in_list, func, PFIL_IN |
(flags & PFIL_WAITOK));
if (flags & PFIL_OUT)
pfil_list_add(&pfil_out_list, func, PFIL_OUT |
(flags & PFIL_WAITOK));
}
static void
pfil_list_add(list, func, flags)
pfil_list_t *list;
int (*func) __P((void *, int, struct ifnet *, int,
struct mbuf **));
int flags;
{
struct packet_filter_hook *pfh;
pfh = (struct packet_filter_hook *)malloc(sizeof(*pfh), M_IFADDR,
flags & PFIL_WAITOK ? M_WAITOK : M_NOWAIT);
if (pfh == NULL)
panic("no memory for packet filter hook");
pfh->pfil_func = func;
/*
* insert the input list in reverse order of the output list
* so that the same path is followed in or out of the kernel.
*/
if (flags & PFIL_IN)
TAILQ_INSERT_HEAD(list, pfh, pfil_link);
else
TAILQ_INSERT_TAIL(list, pfh, pfil_link);
}
/*
* pfil_remove_hook removes a specific function from the packet filter
* hook list.
*/
void
pfil_remove_hook(func, flags)
int (*func) __P((void *, int, struct ifnet *, int,
struct mbuf **));
int flags;
{
if (done_pfil_init == 0)
pfil_init();
if (flags & PFIL_IN)
pfil_list_remove(&pfil_in_list, func);
if (flags & PFIL_OUT)
pfil_list_remove(&pfil_out_list, func);
}
/*
* pfil_list_remove is an internal function that takes a function off the
* specified list.
*/
static void
pfil_list_remove(list, func)
pfil_list_t *list;
int (*func) __P((void *, int, struct ifnet *, int,
struct mbuf **));
{
struct packet_filter_hook *pfh;
for (pfh = list->tqh_first; pfh; pfh = pfh->pfil_link.tqe_next)
if (pfh->pfil_func == func) {
TAILQ_REMOVE(list, pfh, pfil_link);
free(pfh, M_IFADDR);
return;
}
1996-10-13 06:10:01 +04:00
printf("pfil_list_remove: no function on list\n");
#ifdef DIAGNOSTIC
panic("pfil_list_remove");
#endif
}
struct packet_filter_hook *
pfil_hook_get(flag)
int flag;
{
if (done_pfil_init)
switch (flag) {
case PFIL_IN:
return (pfil_in_list.tqh_first);
case PFIL_OUT:
return (pfil_out_list.tqh_first);
}
return NULL;
}