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/* $FreeBSD$ */
/*
* 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/queue.h>
#include <net/if.h>
#include <net/pfil.h>
static void pfil_init(struct pfil_head *);
static int pfil_list_add(pfil_list_t *,
int (*)(void *, int, struct ifnet *, int, struct mbuf **), int);
static int pfil_list_remove(pfil_list_t *,
int (*)(void *, int, struct ifnet *, int, struct mbuf **));
static void
pfil_init(ph)
struct pfil_head *ph;
{
TAILQ_INIT(&ph->ph_in);
TAILQ_INIT(&ph->ph_out);
ph->ph_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.
*/
int
pfil_add_hook(func, flags, ph)
int (*func)(void *, int, struct ifnet *, int, struct mbuf **);
int flags;
struct pfil_head *ph;
{
int err = 0;
if (ph->ph_init == 0)
pfil_init(ph);
if (flags & PFIL_IN)
err = pfil_list_add(&ph->ph_in, func, flags & ~PFIL_OUT);
if (err)
return err;
if (flags & PFIL_OUT)
err = pfil_list_add(&ph->ph_out, func, flags & ~PFIL_IN);
if (err) {
if (flags & PFIL_IN)
pfil_list_remove(&ph->ph_in, func);
return err;
}
return 0;
}
static int
pfil_list_add(list, func, flags)
pfil_list_t *list;
int (*func)(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)
return ENOMEM;
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);
return 0;
}
/*
* pfil_remove_hook removes a specific function from the packet filter
* hook list.
*/
int
pfil_remove_hook(func, flags, ph)
int (*func)(void *, int, struct ifnet *, int, struct mbuf **);
int flags;
struct pfil_head *ph;
{
int err = 0;
if (ph->ph_init == 0)
pfil_init(ph);
if (flags & PFIL_IN)
err = pfil_list_remove(&ph->ph_in, func);
if ((err == 0) && (flags & PFIL_OUT))
err = pfil_list_remove(&ph->ph_out, func);
return err;
}
/*
* pfil_list_remove is an internal function that takes a function off the
* specified list.
*/
static int
pfil_list_remove(list, func)
pfil_list_t *list;
int (*func)(void *, int, struct ifnet *, int, struct mbuf **);
{
struct packet_filter_hook *pfh;
TAILQ_FOREACH(pfh, list, pfil_link)
if (pfh->pfil_func == func) {
TAILQ_REMOVE(list, pfh, pfil_link);
free(pfh, M_IFADDR);
return 0;
}
return ENOENT;
}
struct packet_filter_hook *
pfil_hook_get(flag, ph)
int flag;
struct pfil_head *ph;
{
if (ph->ph_init != 0)
switch (flag) {
case PFIL_IN:
return (TAILQ_FIRST(&ph->ph_in));
case PFIL_OUT:
return (TAILQ_FIRST(&ph->ph_out));
}
return NULL;
}
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