#include <machine/rtems-bsd-kernel-space.h>
/* $FreeBSD$ */
/* $NetBSD: pfil.c,v 1.20 2001/11/12 23:49:46 lukem Exp $ */
/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* 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/if_var.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 struct packet_filter_hook *pfil_chain_get(int, struct pfil_head *);
static int pfil_chain_add(pfil_chain_t *, struct packet_filter_hook *, int);
static int pfil_chain_remove(pfil_chain_t *, void *, void *);
static int pfil_add_hook_priv(void *, void *, int, struct pfil_head *, bool);
LIST_HEAD(pfilheadhead, pfil_head);
VNET_DEFINE(struct pfilheadhead, pfil_head_list);
#define V_pfil_head_list VNET(pfil_head_list)
VNET_DEFINE(struct rmlock, pfil_lock);
#define PFIL_LOCK_INIT_REAL(l, t) \
rm_init_flags(l, "PFil " t " rmlock", RM_RECURSE)
#define PFIL_LOCK_DESTROY_REAL(l) \
rm_destroy(l)
#define PFIL_LOCK_INIT(p) do { \
if ((p)->flags & PFIL_FLAG_PRIVATE_LOCK) { \
PFIL_LOCK_INIT_REAL(&(p)->ph_lock, "private"); \
(p)->ph_plock = &(p)->ph_lock; \
} else \
(p)->ph_plock = &V_pfil_lock; \
} while (0)
#define PFIL_LOCK_DESTROY(p) do { \
if ((p)->flags & PFIL_FLAG_PRIVATE_LOCK) \
PFIL_LOCK_DESTROY_REAL((p)->ph_plock); \
} while (0)
#define PFIL_TRY_RLOCK(p, t) rm_try_rlock((p)->ph_plock, (t))
#define PFIL_RLOCK(p, t) rm_rlock((p)->ph_plock, (t))
#define PFIL_WLOCK(p) rm_wlock((p)->ph_plock)
#define PFIL_RUNLOCK(p, t) rm_runlock((p)->ph_plock, (t))
#define PFIL_WUNLOCK(p) rm_wunlock((p)->ph_plock)
#define PFIL_WOWNED(p) rm_wowned((p)->ph_plock)
#define PFIL_HEADLIST_LOCK() mtx_lock(&pfil_global_lock)
#define PFIL_HEADLIST_UNLOCK() mtx_unlock(&pfil_global_lock)
/*
* pfil_run_hooks() runs the specified packet filter hook chain.
*/
int
pfil_run_hooks(struct pfil_head *ph, struct mbuf **mp, struct ifnet *ifp,
int dir, int flags, 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_chain_get(dir, ph); pfh != NULL;
pfh = TAILQ_NEXT(pfh, pfil_chain)) {
if (pfh->pfil_func_flags != NULL) {
rv = (*pfh->pfil_func_flags)(pfh->pfil_arg, &m, ifp,
dir, flags, inp);
if (rv != 0 || m == NULL)
break;
}
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);
}
static struct packet_filter_hook *
pfil_chain_get(int dir, struct pfil_head *ph)
{
if (dir == PFIL_IN)
return (TAILQ_FIRST(&ph->ph_in));
else if (dir == PFIL_OUT)
return (TAILQ_FIRST(&ph->ph_out));
else
return (NULL);
}
#ifndef __rtems__
/*
* pfil_try_rlock() acquires rm reader lock for specified head
* if this is immediately possible.
*/
int
pfil_try_rlock(struct pfil_head *ph, struct rm_priotracker *tracker)
{
return (PFIL_TRY_RLOCK(ph, tracker));
}
#endif /* __rtems__ */
/*
* pfil_rlock() acquires rm reader lock for specified head.
*/
void
pfil_rlock(struct pfil_head *ph, struct rm_priotracker *tracker)
{
PFIL_RLOCK(ph, tracker);
}
/*
* pfil_runlock() releases reader lock for specified head.
*/
void
pfil_runlock(struct pfil_head *ph, struct rm_priotracker *tracker)
{
PFIL_RUNLOCK(ph, tracker);
}
/*
* pfil_wlock() acquires writer lock for specified head.
*/
void
pfil_wlock(struct pfil_head *ph)
{
PFIL_WLOCK(ph);
}
/*
* pfil_wunlock() releases writer lock for specified head.
*/
void
pfil_wunlock(struct pfil_head *ph)
{
PFIL_WUNLOCK(ph);
}
/*
* pfil_wowned() returns a non-zero value if the current thread owns
* an exclusive lock.
*/
int
pfil_wowned(struct pfil_head *ph)
{
return (PFIL_WOWNED(ph));
}
/*
* 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_HEADLIST_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_HEADLIST_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_HEADLIST_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_HEADLIST_LOCK();
LIST_REMOVE(ph, ph_list);
PFIL_HEADLIST_UNLOCK();
TAILQ_FOREACH_SAFE(pfh, &ph->ph_in, pfil_chain, pfnext)
free(pfh, M_IFADDR);
TAILQ_FOREACH_SAFE(pfh, &ph->ph_out, pfil_chain, 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_HEADLIST_LOCK();
LIST_FOREACH(ph, &V_pfil_head_list, ph_list)
if (ph->ph_type == type && ph->ph_un.phu_val == val)
break;
PFIL_HEADLIST_UNLOCK();
return (ph);
}
/*
* pfil_add_hook_flags() 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_flags(pfil_func_flags_t func, void *arg, int flags,
struct pfil_head *ph)
{
return (pfil_add_hook_priv(func, arg, flags, ph, true));
}
/*
* 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(pfil_func_t func, void *arg, int flags, struct pfil_head *ph)
{
return (pfil_add_hook_priv(func, arg, flags, ph, false));
}
static int
pfil_add_hook_priv(void *func, void *arg, int flags,
struct pfil_head *ph, bool hasflags)
{
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_flags = hasflags ? func : NULL;
pfh1->pfil_func = hasflags ? NULL : func;
pfh1->pfil_arg = arg;
err = pfil_chain_add(&ph->ph_in, pfh1, flags & ~PFIL_OUT);
if (err)
goto locked_error;
ph->ph_nhooks++;
}
if (flags & PFIL_OUT) {
pfh2->pfil_func_flags = hasflags ? func : NULL;
pfh2->pfil_func = hasflags ? NULL : func;
pfh2->pfil_arg = arg;
err = pfil_chain_add(&ph->ph_out, pfh2, flags & ~PFIL_IN);
if (err) {
if (flags & PFIL_IN)
pfil_chain_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_flags removes a specific function from the packet filter hook
* chain.
*/
int
pfil_remove_hook_flags(pfil_func_flags_t func, void *arg, int flags,
struct pfil_head *ph)
{
return (pfil_remove_hook((pfil_func_t)func, arg, flags, ph));
}
/*
* pfil_remove_hook removes a specific function from the packet filter hook
* chain.
*/
int
pfil_remove_hook(pfil_func_t func, void *arg, int flags, struct pfil_head *ph)
{
int err = 0;
PFIL_WLOCK(ph);
if (flags & PFIL_IN) {
err = pfil_chain_remove(&ph->ph_in, func, arg);
if (err == 0)
ph->ph_nhooks--;
}
if ((err == 0) && (flags & PFIL_OUT)) {
err = pfil_chain_remove(&ph->ph_out, func, arg);
if (err == 0)
ph->ph_nhooks--;
}
PFIL_WUNLOCK(ph);
return (err);
}
/*
* Internal: Add a new pfil hook into a hook chain.
*/
static int
pfil_chain_add(pfil_chain_t *chain, struct packet_filter_hook *pfh1, int flags)
{
struct packet_filter_hook *pfh;
/*
* First make sure the hook is not already there.
*/
TAILQ_FOREACH(pfh, chain, pfil_chain)
if (((pfh->pfil_func != NULL && pfh->pfil_func == pfh1->pfil_func) ||
(pfh->pfil_func_flags != NULL &&
pfh->pfil_func_flags == pfh1->pfil_func_flags)) &&
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(chain, pfh1, pfil_chain);
else
TAILQ_INSERT_TAIL(chain, pfh1, pfil_chain);
return (0);
}
/*
* Internal: Remove a pfil hook from a hook chain.
*/
static int
pfil_chain_remove(pfil_chain_t *chain, void *func, void *arg)
{
struct packet_filter_hook *pfh;
TAILQ_FOREACH(pfh, chain, pfil_chain)
if ((pfh->pfil_func == func || pfh->pfil_func_flags == func) &&
pfh->pfil_arg == arg) {
TAILQ_REMOVE(chain, pfh, pfil_chain);
free(pfh, M_IFADDR);
return (0);
}
return (ENOENT);
}
/*
* Stuff that must be initialized for every instance (including the first of
* course).
*/
static void
vnet_pfil_init(const void *unused __unused)
{
LIST_INIT(&V_pfil_head_list);
PFIL_LOCK_INIT_REAL(&V_pfil_lock, "shared");
}
/*
* Called for the removal of each instance.
*/
static void
vnet_pfil_uninit(const void *unused __unused)
{
KASSERT(LIST_EMPTY(&V_pfil_head_list),
("%s: pfil_head_list %p not empty", __func__, &V_pfil_head_list));
PFIL_LOCK_DESTROY_REAL(&V_pfil_lock);
}
/*
* Starting up.
*
* VNET_SYSINIT is called for each existing vnet and each new vnet.
* Make sure the pfil bits are first before any possible subsystem which
* might piggyback on the SI_SUB_PROTO_PFIL.
*/
VNET_SYSINIT(vnet_pfil_init, SI_SUB_PROTO_PFIL, SI_ORDER_FIRST,
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, SI_SUB_PROTO_PFIL, SI_ORDER_FIRST,
vnet_pfil_uninit, NULL);
