NetBSD-5.0.2/sys/net/pfil.c
/* $NetBSD: pfil.c,v 1.27 2008/06/23 03:13:12 dyoung 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.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: pfil.c,v 1.27 2008/06/23 03:13:12 dyoung Exp $");
#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>
static int pfil_list_add(pfil_list_t *,
int (*)(void *, struct mbuf **, struct ifnet *, int), void *, int);
static int pfil_list_remove(pfil_list_t *,
int (*)(void *, struct mbuf **, struct ifnet *, int), void *);
LIST_HEAD(, pfil_head) pfil_head_list =
LIST_HEAD_INITIALIZER(&pfil_head_list);
/*
* pfil_run_hooks() runs the specified packet filter hooks.
*/
int
pfil_run_hooks(struct pfil_head *ph, struct mbuf **mp, struct ifnet *ifp,
int dir)
{
struct packet_filter_hook *pfh;
struct mbuf *m = NULL;
int rv = 0;
if ((dir & PFIL_ALL) && mp)
m = *mp;
for (pfh = pfil_hook_get(dir, ph); pfh != NULL;
pfh = TAILQ_NEXT(pfh, pfil_link)) {
if (pfh->pfil_func != NULL) {
if (pfh->pfil_flags & PFIL_ALL) {
rv = (*pfh->pfil_func)(pfh->pfil_arg, &m, ifp,
dir);
if (rv != 0 || m == NULL)
break;
} else {
rv = (*pfh->pfil_func)(pfh->pfil_arg, mp, ifp,
dir);
if (rv != 0)
break;
}
}
}
if ((dir & PFIL_ALL) && mp)
*mp = m;
return (rv);
}
/*
* pfil_head_register() registers a pfil_head with the packet filter
* hook mechanism.
*/
int
pfil_head_register(struct pfil_head *ph)
{
struct pfil_head *lph;
LIST_FOREACH(lph, &pfil_head_list, ph_list) {
if (ph->ph_type == lph->ph_type &&
ph->ph_un.phu_val == lph->ph_un.phu_val)
return EEXIST;
}
TAILQ_INIT(&ph->ph_in);
TAILQ_INIT(&ph->ph_out);
TAILQ_INIT(&ph->ph_ifaddr);
TAILQ_INIT(&ph->ph_ifnetevent);
LIST_INSERT_HEAD(&pfil_head_list, ph, ph_list);
return (0);
}
/*
* pfil_head_unregister() removes a pfil_head from the packet filter
* hook mechanism.
*/
int
pfil_head_unregister(struct pfil_head *pfh)
{
LIST_REMOVE(pfh, ph_list);
return (0);
}
/*
* pfil_head_get() returns the pfil_head for a given key/dlt.
*/
struct pfil_head *
pfil_head_get(int type, u_long val)
{
struct pfil_head *ph;
LIST_FOREACH(ph, &pfil_head_list, ph_list) {
if (ph->ph_type == type && ph->ph_un.phu_val == val)
break;
}
return (ph);
}
/*
* 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_IFADDR call me on interface reconfig (mbuf ** is ioctl #)
* PFIL_IFNET call me on interface attach/detach
* (mbuf ** is PFIL_IFNET_*)
* PFIL_WAITOK OK to call malloc with M_WAITOK.
*/
int
pfil_add_hook(int (*func)(void *, struct mbuf **, struct ifnet *, int),
void *arg, int flags, struct pfil_head *ph)
{
int err = 0;
if (flags & PFIL_IN) {
err = pfil_list_add(&ph->ph_in, func, arg, flags & ~PFIL_OUT);
if (err)
return err;
}
if (flags & PFIL_OUT) {
err = pfil_list_add(&ph->ph_out, func, arg, flags & ~PFIL_IN);
if (err) {
if (flags & PFIL_IN)
pfil_list_remove(&ph->ph_in, func, arg);
return err;
}
}
if (flags & PFIL_IFADDR) {
err = pfil_list_add(&ph->ph_ifaddr, func, arg, flags);
if (err) {
if (flags & PFIL_IN)
pfil_list_remove(&ph->ph_in, func, arg);
if (flags & PFIL_OUT)
pfil_list_remove(&ph->ph_out, func, arg);
return err;
}
}
if (flags & PFIL_IFNET) {
err = pfil_list_add(&ph->ph_ifnetevent, func, arg, flags);
if (err) {
if (flags & PFIL_IN)
pfil_list_remove(&ph->ph_in, func, arg);
if (flags & PFIL_OUT)
pfil_list_remove(&ph->ph_out, func, arg);
if (flags & PFIL_IFADDR)
pfil_list_remove(&ph->ph_ifaddr, func, arg);
return err;
}
}
return 0;
}
static int
pfil_list_add(pfil_list_t *list,
int (*func)(void *, struct mbuf **, struct ifnet *, int), void *arg,
int flags)
{
struct packet_filter_hook *pfh;
/*
* First make sure the hook is not already there.
*/
TAILQ_FOREACH(pfh, list, pfil_link) {
if (pfh->pfil_func == func && pfh->pfil_arg == arg)
return EEXIST;
}
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;
pfh->pfil_arg = arg;
pfh->pfil_flags = flags;
/*
* 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(int (*func)(void *, struct mbuf **, struct ifnet *, int),
void *arg, int flags, struct pfil_head *ph)
{
int err = 0;
if (flags & PFIL_IN)
err = pfil_list_remove(&ph->ph_in, func, arg);
if ((err == 0) && (flags & PFIL_OUT))
err = pfil_list_remove(&ph->ph_out, func, arg);
if ((err == 0) && (flags & PFIL_IFADDR))
err = pfil_list_remove(&ph->ph_ifaddr, func, arg);
if ((err == 0) && (flags & PFIL_IFNET))
err = pfil_list_remove(&ph->ph_ifnetevent, func, arg);
return err;
}
/*
* pfil_list_remove is an internal function that takes a function off the
* specified list.
*/
static int
pfil_list_remove(pfil_list_t *list,
int (*func)(void *, struct mbuf **, struct ifnet *, int), void *arg)
{
struct packet_filter_hook *pfh;
TAILQ_FOREACH(pfh, list, pfil_link) {
if (pfh->pfil_func == func && pfh->pfil_arg == arg) {
TAILQ_REMOVE(list, pfh, pfil_link);
free(pfh, M_IFADDR);
return 0;
}
}
return ENOENT;
}