/* $FreeBSD$ */
/* $NetBSD: pfil.c,v 1.20 2001/11/12 23:49:46 lukem 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/kernel.h>
#include <sys/errno.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/rmlock.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/systm.h>
#include <sys/condvar.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/queue.h>
#include <net/if.h>
#include <net/pfil.h>
static struct mtx pfil_global_lock;
MTX_SYSINIT(pfil_heads_lock, &pfil_global_lock, "pfil_head_list lock",
MTX_DEF);
static int pfil_list_add(pfil_list_t *, struct packet_filter_hook *, int);
static int pfil_list_remove(pfil_list_t *,
int (*)(void *, struct mbuf **, struct ifnet *, int, struct inpcb *),
void *);
LIST_HEAD(pfilheadhead, pfil_head);
VNET_DEFINE(struct pfilheadhead, pfil_head_list);
#define V_pfil_head_list VNET(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 inpcb *inp)
{
struct rm_priotracker rmpt;
struct packet_filter_hook *pfh;
struct mbuf *m = *mp;
int rv = 0;
PFIL_RLOCK(ph, &rmpt);
KASSERT(ph->ph_nhooks >= 0, ("Pfil hook count dropped < 0"));
for (pfh = pfil_hook_get(dir, ph); pfh != NULL;
pfh = TAILQ_NEXT(pfh, pfil_link)) {
if (pfh->pfil_func != NULL) {
rv = (*pfh->pfil_func)(pfh->pfil_arg, &m, ifp, dir,
inp);
if (rv != 0 || m == NULL)
break;
}
}
PFIL_RUNLOCK(ph, &rmpt);
*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;
PFIL_LIST_LOCK();
LIST_FOREACH(lph, &V_pfil_head_list, ph_list) {
if (ph->ph_type == lph->ph_type &&
ph->ph_un.phu_val == lph->ph_un.phu_val) {
PFIL_LIST_UNLOCK();
return (EEXIST);
}
}
PFIL_LOCK_INIT(ph);
ph->ph_nhooks = 0;
TAILQ_INIT(&ph->ph_in);
TAILQ_INIT(&ph->ph_out);
LIST_INSERT_HEAD(&V_pfil_head_list, ph, ph_list);
PFIL_LIST_UNLOCK();
return (0);
}
/*
* pfil_head_unregister() removes a pfil_head from the packet filter hook
* mechanism. The producer of the hook promises that all outstanding
* invocations of the hook have completed before it unregisters the hook.
*/
int
pfil_head_unregister(struct pfil_head *ph)
{
struct packet_filter_hook *pfh, *pfnext;
PFIL_LIST_LOCK();
LIST_REMOVE(ph, ph_list);
PFIL_LIST_UNLOCK();
TAILQ_FOREACH_SAFE(pfh, &ph->ph_in, pfil_link, pfnext)
free(pfh, M_IFADDR);
TAILQ_FOREACH_SAFE(pfh, &ph->ph_out, pfil_link, pfnext)
free(pfh, M_IFADDR);
PFIL_LOCK_DESTROY(ph);
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;
PFIL_LIST_LOCK();
LIST_FOREACH(ph, &V_pfil_head_list, ph_list)
if (ph->ph_type == type && ph->ph_un.phu_val == val)
break;
PFIL_LIST_UNLOCK();
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_WAITOK OK to call malloc with M_WAITOK.
*/
int
pfil_add_hook(int (*func)(void *, struct mbuf **, struct ifnet *, int,
struct inpcb *), void *arg, int flags, struct pfil_head *ph)
{
struct packet_filter_hook *pfh1 = NULL;
struct packet_filter_hook *pfh2 = NULL;
int err;
if (flags & PFIL_IN) {
pfh1 = (struct packet_filter_hook *)malloc(sizeof(*pfh1),
M_IFADDR, (flags & PFIL_WAITOK) ? M_WAITOK : M_NOWAIT);
if (pfh1 == NULL) {
err = ENOMEM;
goto error;
}
}
if (flags & PFIL_OUT) {
pfh2 = (struct packet_filter_hook *)malloc(sizeof(*pfh1),
M_IFADDR, (flags & PFIL_WAITOK) ? M_WAITOK : M_NOWAIT);
if (pfh2 == NULL) {
err = ENOMEM;
goto error;
}
}
PFIL_WLOCK(ph);
if (flags & PFIL_IN) {
pfh1->pfil_func = func;
pfh1->pfil_arg = arg;
err = pfil_list_add(&ph->ph_in, pfh1, flags & ~PFIL_OUT);
if (err)
goto locked_error;
ph->ph_nhooks++;
}
if (flags & PFIL_OUT) {
pfh2->pfil_func = func;
pfh2->pfil_arg = arg;
err = pfil_list_add(&ph->ph_out, pfh2, flags & ~PFIL_IN);
if (err) {
if (flags & PFIL_IN)
pfil_list_remove(&ph->ph_in, func, arg);
goto locked_error;
}
ph->ph_nhooks++;
}
PFIL_WUNLOCK(ph);
return (0);
locked_error:
PFIL_WUNLOCK(ph);
error:
if (pfh1 != NULL)
free(pfh1, M_IFADDR);
if (pfh2 != NULL)
free(pfh2, M_IFADDR);
return (err);
}
/*
* 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,
struct inpcb *), void *arg, int flags, struct pfil_head *ph)
{
int err = 0;
PFIL_WLOCK(ph);
if (flags & PFIL_IN) {
err = pfil_list_remove(&ph->ph_in, func, arg);
if (err == 0)
ph->ph_nhooks--;
}
if ((err == 0) && (flags & PFIL_OUT)) {
err = pfil_list_remove(&ph->ph_out, func, arg);
if (err == 0)
ph->ph_nhooks--;
}
PFIL_WUNLOCK(ph);
return (err);
}
static int
pfil_list_add(pfil_list_t *list, struct packet_filter_hook *pfh1, 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 == pfh1->pfil_func &&
pfh->pfil_arg == pfh1->pfil_arg)
return (EEXIST);
/*
* 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, pfh1, pfil_link);
else
TAILQ_INSERT_TAIL(list, pfh1, pfil_link);
return (0);
}
/*
* 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, struct inpcb *),
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);
}
/*
* Stuff that must be initialized for every instance (including the first of
* course).
*/
static int
vnet_pfil_init(const void *unused)
{
LIST_INIT(&V_pfil_head_list);
return (0);
}
/*
* Called for the removal of each instance.
*/
static int
vnet_pfil_uninit(const void *unused)
{
/* XXX should panic if list is not empty */
return (0);
}
/* Define startup order. */
#define PFIL_SYSINIT_ORDER SI_SUB_PROTO_BEGIN
#define PFIL_MODEVENT_ORDER (SI_ORDER_FIRST) /* On boot slot in here. */
#define PFIL_VNET_ORDER (PFIL_MODEVENT_ORDER + 2) /* Later still. */
/*
* Starting up.
*
* VNET_SYSINIT is called for each existing vnet and each new vnet.
*/
VNET_SYSINIT(vnet_pfil_init, PFIL_SYSINIT_ORDER, PFIL_VNET_ORDER,
vnet_pfil_init, NULL);
/*
* Closing up shop. These are done in REVERSE ORDER. Not called on reboot.
*
* VNET_SYSUNINIT is called for each exiting vnet as it exits.
*/
VNET_SYSUNINIT(vnet_pfil_uninit, PFIL_SYSINIT_ORDER, PFIL_VNET_ORDER,
vnet_pfil_uninit, NULL);
