[dragonfly.git] / sys / net / pfil.c

/*	$NetBSD: pfil.c,v 1.20 2001/11/12 23:49:46 lukem Exp $	*/
/* $DragonFly: src/sys/net/pfil.c,v 1.14 2008/09/20 06:08:13 sephe 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>
#include <net/netmsg2.h>
#include <net/netisr2.h>
#include <sys/mplock2.h>

#define PFIL_CFGPORT	netisr_cpuport(0)

#define PFIL_GETMPLOCK(pfh) \
do { \
	if (((pfh)->pfil_flags & PFIL_MPSAFE) == 0) \
		get_mplock(); \
} while (0)

#define PFIL_RELMPLOCK(pfh) \
do { \
	if (((pfh)->pfil_flags & PFIL_MPSAFE) == 0) \
		rel_mplock(); \
} while (0)

/*
 * The packet filter hooks are designed for anything to call them to
 * possibly intercept the packet.
 */
struct packet_filter_hook {
        TAILQ_ENTRY(packet_filter_hook) pfil_link;
	pfil_func_t	pfil_func;
	void		*pfil_arg;
	int		pfil_flags;
};

struct netmsg_pfil {
	struct netmsg_base	base;
	pfil_func_t		pfil_func;
	void			*pfil_arg;
	int			pfil_flags;
	struct pfil_head	*pfil_ph;
};

static LIST_HEAD(, pfil_head) pfil_head_list =
	LIST_HEAD_INITIALIZER(&pfil_head_list);

static pfil_list_t	*pfil_list_alloc(void);
static void		pfil_list_free(pfil_list_t *);
static void 		pfil_list_dup(const pfil_list_t *, pfil_list_t *,
				      const struct packet_filter_hook *);
static void 		pfil_list_add(pfil_list_t *, pfil_func_t, void *, int);
static struct packet_filter_hook *
			pfil_list_find(const pfil_list_t *, pfil_func_t,
				       const void *);

static void		pfil_remove_hook_dispatch(netmsg_t);
static void		pfil_add_hook_dispatch(netmsg_t);

/*
 * 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 = *mp;
	pfil_list_t *list;
	int rv = 0;

	if (dir == PFIL_IN)
		list = ph->ph_in;
	else if (dir == PFIL_OUT)
		list = ph->ph_out;
	else
		return 0; /* XXX panic? */

	TAILQ_FOREACH(pfh, list, pfil_link) {
		if (pfh->pfil_func != NULL) {
			PFIL_GETMPLOCK(pfh);
			rv = pfh->pfil_func(pfh->pfil_arg, &m, ifp, dir);
			PFIL_RELMPLOCK(pfh);

			if (rv != 0 || m == NULL)
				break;
		}
	}

	*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;
	}

	ph->ph_in = pfil_list_alloc();
	ph->ph_out = pfil_list_alloc();
	ph->ph_hashooks = 0;

	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);
}

static void
pfil_add_hook_dispatch(netmsg_t nmsg)
{
	struct netmsg_pfil *pfilmsg = (struct netmsg_pfil *)nmsg;
	pfil_func_t func = pfilmsg->pfil_func;
	void *arg = pfilmsg->pfil_arg;
	int flags = pfilmsg->pfil_flags;
	struct pfil_head *ph = pfilmsg->pfil_ph;
	const struct packet_filter_hook *pfh;
	pfil_list_t *list_in = NULL, *list_out = NULL;
	pfil_list_t *old_list_in = NULL, *old_list_out = NULL;
	int err = 0;

	/* This probably should not happen ... */
	if ((flags & (PFIL_IN | PFIL_OUT)) == 0)
		goto reply; /* XXX panic? */

	/*
	 * If pfil hooks exist on any of the requested lists,
	 * then bail out.
	 */
	if (flags & PFIL_IN) {
		pfh = pfil_list_find(ph->ph_in, func, arg);
		if (pfh != NULL) {
			err = EEXIST;
			goto reply;
		}
	}
	if (flags & PFIL_OUT) {
		pfh = pfil_list_find(ph->ph_out, func, arg);
		if (pfh != NULL) {
			err = EEXIST;
			goto reply;
		}
	}

	/*
	 * Duplicate the requested lists, install new hooks
	 * on the duplication
	 */
	if (flags & PFIL_IN) {
		list_in = pfil_list_alloc();
		pfil_list_dup(ph->ph_in, list_in, NULL);
		pfil_list_add(list_in, func, arg, flags & ~PFIL_OUT);
	}
	if (flags & PFIL_OUT) {
		list_out = pfil_list_alloc();
		pfil_list_dup(ph->ph_out, list_out, NULL);
		pfil_list_add(list_out, func, arg, flags & ~PFIL_IN);
	}

	/*
	 * Switch list pointers, but keep the old ones
	 */
	if (list_in != NULL) {
		old_list_in = ph->ph_in;
		ph->ph_in = list_in;
	}
	if (list_out != NULL) {
		old_list_out = ph->ph_out;
		ph->ph_out = list_out;
	}

	/*
	 * Wait until everyone has finished the old lists iteration
	 */
	netmsg_service_sync();
	ph->ph_hashooks = 1;

	/*
	 * Now it is safe to free the old lists, since no one sees it
	 */
	if (old_list_in != NULL)
		pfil_list_free(old_list_in);
	if (old_list_out != NULL)
		pfil_list_free(old_list_out);
reply:
	lwkt_replymsg(&nmsg->base.lmsg, err);
}

/*
 * 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_MPSAFE	call me without BGL
 */
int
pfil_add_hook(pfil_func_t func, void *arg, int flags, struct pfil_head *ph)
{
	struct netmsg_pfil pfilmsg;
	netmsg_base_t nmsg;
	int error;

	nmsg = &pfilmsg.base;
	netmsg_init(nmsg, NULL, &curthread->td_msgport,
		    0, pfil_add_hook_dispatch);
	pfilmsg.pfil_func = func;
	pfilmsg.pfil_arg = arg;
	pfilmsg.pfil_flags = flags;
	pfilmsg.pfil_ph = ph;

	error = lwkt_domsg(PFIL_CFGPORT, &nmsg->lmsg, 0);
	return error;
}

static void
pfil_remove_hook_dispatch(netmsg_t nmsg)
{
	struct netmsg_pfil *pfilmsg = (struct netmsg_pfil *)nmsg;
	pfil_func_t func = pfilmsg->pfil_func;
	void *arg = pfilmsg->pfil_arg;
	int flags = pfilmsg->pfil_flags;
	struct pfil_head *ph = pfilmsg->pfil_ph;
	struct packet_filter_hook *skip_in = NULL, *skip_out = NULL;
	pfil_list_t *list_in = NULL, *list_out = NULL;
	pfil_list_t *old_list_in = NULL, *old_list_out = NULL;
	int err = 0;

	/* This probably should not happen ... */
	if ((flags & (PFIL_IN | PFIL_OUT)) == 0)
		goto reply; /* XXX panic? */

	/*
	 * The pfil hook should exist on all requested lists,
	 * if not just bail out
	 */
	if (flags & PFIL_IN) {
		skip_in = pfil_list_find(ph->ph_in, func, arg);
		if (!skip_in) {
			err = ENOENT;
			goto reply;
		}
	}
	if (flags & PFIL_OUT) {
		skip_out = pfil_list_find(ph->ph_out, func, arg);
		if (!skip_out) {
			err = ENOENT;
			goto reply;
		}
	}

	/*
	 * Duplicate the requested lists, but the pfil hook to
	 * be deleted is not copied
	 */
	if (flags & PFIL_IN) {
		KKASSERT(skip_in != NULL);
		list_in = pfil_list_alloc();
		pfil_list_dup(ph->ph_in, list_in, skip_in);
	}
	if (flags & PFIL_OUT) {
		KKASSERT(skip_out != NULL);
		list_out = pfil_list_alloc();
		pfil_list_dup(ph->ph_out, list_out, skip_out);
	}

	/*
	 * Switch list pointers, but keep the old ones
	 */
	if (list_in != NULL) {
		old_list_in = ph->ph_in;
		ph->ph_in = list_in;
	}
	if (list_out != NULL) {
		old_list_out = ph->ph_out;
		ph->ph_out = list_out;
	}

	/*
	 * Wait until everyone has finished the old lists iteration
	 */
	if (TAILQ_EMPTY(ph->ph_in) && TAILQ_EMPTY(ph->ph_out))
		ph->ph_hashooks = 0;
	netmsg_service_sync();

	/*
	 * Now it is safe to free the old lists, since no one sees it
	 */
	if (old_list_in != NULL)
		pfil_list_free(old_list_in);
	if (old_list_out != NULL)
		pfil_list_free(old_list_out);
reply:
	lwkt_replymsg(&nmsg->base.lmsg, err);
}

/*
 * pfil_remove_hook removes a specific function from the packet filter
 * hook list.
 */
int
pfil_remove_hook(pfil_func_t func, void *arg, int flags, struct pfil_head *ph)
{
	struct netmsg_pfil pfilmsg;
	netmsg_base_t nmsg;

	nmsg = &pfilmsg.base;
	netmsg_init(nmsg, NULL, &curthread->td_msgport,
		    0, pfil_remove_hook_dispatch);
	pfilmsg.pfil_func = func;
	pfilmsg.pfil_arg = arg;
	pfilmsg.pfil_flags = flags;
	pfilmsg.pfil_ph = ph;

	return lwkt_domsg(PFIL_CFGPORT, &nmsg->lmsg, 0);
}

static void
pfil_list_add(pfil_list_t *list, pfil_func_t func, void *arg, int flags)
{
	struct packet_filter_hook *pfh;

	KKASSERT(&curthread->td_msgport == PFIL_CFGPORT);

	pfh = kmalloc(sizeof(*pfh), M_IFADDR, M_WAITOK);

	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);
}

static void
pfil_list_dup(const pfil_list_t *from, pfil_list_t *to,
	      const struct packet_filter_hook *skip)
{
	struct packet_filter_hook *pfh_to, *pfh_from;

	KKASSERT(&curthread->td_msgport == PFIL_CFGPORT);
	KKASSERT(TAILQ_EMPTY(to));

	TAILQ_FOREACH(pfh_from, from, pfil_link) {
		if (pfh_from == skip)
			continue;

		pfh_to = kmalloc(sizeof(*pfh_to), M_IFADDR, M_WAITOK);
		bcopy(pfh_from, pfh_to, sizeof(*pfh_to));

		TAILQ_INSERT_TAIL(to, pfh_to, pfil_link);
	}
}

static pfil_list_t *
pfil_list_alloc(void)
{
	pfil_list_t *list;

	list = kmalloc(sizeof(*list), M_IFADDR, M_WAITOK);
	TAILQ_INIT(list);
	return list;
}

static void
pfil_list_free(pfil_list_t *list)
{
	struct packet_filter_hook *pfh;

	while ((pfh = TAILQ_FIRST(list)) != NULL) {
		TAILQ_REMOVE(list, pfh, pfil_link);
		kfree(pfh, M_IFADDR);
	}
	kfree(list, M_IFADDR);
}

static struct packet_filter_hook *
pfil_list_find(const pfil_list_t *list, pfil_func_t func, const void *arg)
{
	struct packet_filter_hook *pfh;

	KKASSERT(&curthread->td_msgport == PFIL_CFGPORT);

	TAILQ_FOREACH(pfh, list, pfil_link) {
		if (pfh->pfil_func == func && pfh->pfil_arg == arg)
			return pfh;
	}
	return NULL;
}
Commit	Line	Data
9e99d0a2	1	/* $NetBSD: pfil.c,v 1.20 2001/11/12 23:49:46 lukem Exp $ */
77e0b69a	2	/* $DragonFly: src/sys/net/pfil.c,v 1.14 2008/09/20 06:08:13 sephe Exp $ */
9e99d0a2 JR	3
	4	/*
	5	* Copyright (c) 1996 Matthew R. Green
	6	* All rights reserved.
	7	*
	8	* Redistribution and use in source and binary forms, with or without
	9	* modification, are permitted provided that the following conditions
	10	* are met:
	11	* 1. Redistributions of source code must retain the above copyright
	12	* notice, this list of conditions and the following disclaimer.
	13	* 2. Redistributions in binary form must reproduce the above copyright
	14	* notice, this list of conditions and the following disclaimer in the
	15	* documentation and/or other materials provided with the distribution.
	16	* 3. The name of the author may not be used to endorse or promote products
	17	* derived from this software without specific prior written permission.
	18	*
	19	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
	20	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	21	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	22	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	23	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
	24	* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
	25	* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
	26	* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
	27	* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	28	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	29	* SUCH DAMAGE.
	30	*/
	31
	32	#include <sys/param.h>
	33	#include <sys/errno.h>
	34	#include <sys/malloc.h>
	35	#include <sys/socket.h>
	36	#include <sys/socketvar.h>
	37	#include <sys/systm.h>
	38	#include <sys/proc.h>
	39	#include <sys/queue.h>
	40
	41	#include <net/if.h>
	42	#include <net/pfil.h>
f0fad8e1	43	#include <net/netmsg2.h>
5337421c	44	#include <net/netisr2.h>
684a93c4	45	#include <sys/mplock2.h>
f0fad8e1	46
ec7f7fc8	47	#define PFIL_CFGPORT netisr_cpuport(0)
77e0b69a SZ	48
	49	#define PFIL_GETMPLOCK(pfh) \
	50	do { \
	51	if (((pfh)->pfil_flags & PFIL_MPSAFE) == 0) \
	52	get_mplock(); \
	53	} while (0)
	54
	55	#define PFIL_RELMPLOCK(pfh) \
	56	do { \
	57	if (((pfh)->pfil_flags & PFIL_MPSAFE) == 0) \
	58	rel_mplock(); \
	59	} while (0)
	60
caa0af9f SZ	61	/*
	62	* The packet filter hooks are designed for anything to call them to
	63	* possibly intercept the packet.
	64	*/
	65	struct packet_filter_hook {
	66	TAILQ_ENTRY(packet_filter_hook) pfil_link;
	67	pfil_func_t pfil_func;
	68	void *pfil_arg;
	69	int pfil_flags;
	70	};
	71
f0fad8e1	72	struct netmsg_pfil {
002c1265	73	struct netmsg_base base;
f0fad8e1 SZ	74	pfil_func_t pfil_func;
	75	void *pfil_arg;
	76	int pfil_flags;
	77	struct pfil_head *pfil_ph;
	78	};
9e99d0a2	79
d66da3ad SZ	80	static LIST_HEAD(, pfil_head) pfil_head_list =
d66da3ad SZ	81	LIST_HEAD_INITIALIZER(&pfil_head_list);
9e99d0a2	82
d66da3ad SZ	83	static pfil_list_t *pfil_list_alloc(void);
	84	static void pfil_list_free(pfil_list_t *);
	85	static void pfil_list_dup(const pfil_list_t , pfil_list_t ,
	86	const struct packet_filter_hook *);
	87	static void pfil_list_add(pfil_list_t , pfil_func_t, void , int);
	88	static struct packet_filter_hook *
	89	pfil_list_find(const pfil_list_t *, pfil_func_t,
	90	const void *);
	91
002c1265 MD	92	static void pfil_remove_hook_dispatch(netmsg_t);
002c1265 MD	93	static void pfil_add_hook_dispatch(netmsg_t);
9e99d0a2 JR	94
	95	/*
	96	* pfil_run_hooks() runs the specified packet filter hooks.
	97	*/
	98	int
	99	pfil_run_hooks(struct pfil_head ph, struct mbuf mp, struct ifnet ifp,
	100	int dir)
	101	{
	102	struct packet_filter_hook *pfh;
	103	struct mbuf m = mp;
7f8565be	104	pfil_list_t *list;
9e99d0a2 JR	105	int rv = 0;
9e99d0a2 JR	106
7f8565be	107	if (dir == PFIL_IN)
d66da3ad	108	list = ph->ph_in;
7f8565be	109	else if (dir == PFIL_OUT)
d66da3ad	110	list = ph->ph_out;
7f8565be SZ	111	else
	112	return 0; /* XXX panic? */
	113
	114	TAILQ_FOREACH(pfh, list, pfil_link) {
9e99d0a2	115	if (pfh->pfil_func != NULL) {
77e0b69a SZ	116	PFIL_GETMPLOCK(pfh);
	117	rv = pfh->pfil_func(pfh->pfil_arg, &m, ifp, dir);
	118	PFIL_RELMPLOCK(pfh);
	119
9e99d0a2 JR	120	if (rv != 0 \|\| m == NULL)
	121	break;
	122	}
	123	}
	124
	125	*mp = m;
	126	return (rv);
	127	}
	128
	129	/*
	130	* pfil_head_register() registers a pfil_head with the packet filter
	131	* hook mechanism.
	132	*/
	133	int
	134	pfil_head_register(struct pfil_head *ph)
	135	{
	136	struct pfil_head *lph;
	137
94171836	138	LIST_FOREACH(lph, &pfil_head_list, ph_list) {
9e99d0a2 JR	139	if (ph->ph_type == lph->ph_type &&
	140	ph->ph_un.phu_val == lph->ph_un.phu_val)
	141	return EEXIST;
	142	}
	143
d66da3ad SZ	144	ph->ph_in = pfil_list_alloc();
d66da3ad SZ	145	ph->ph_out = pfil_list_alloc();
afabe90c	146	ph->ph_hashooks = 0;
9e99d0a2 JR	147
	148	LIST_INSERT_HEAD(&pfil_head_list, ph, ph_list);
	149
	150	return (0);
	151	}
	152
	153	/*
	154	* pfil_head_unregister() removes a pfil_head from the packet filter
	155	* hook mechanism.
	156	*/
	157	int
	158	pfil_head_unregister(struct pfil_head *pfh)
	159	{
9e99d0a2 JR	160	LIST_REMOVE(pfh, ph_list);
	161	return (0);
	162	}
	163
	164	/*
	165	* pfil_head_get() returns the pfil_head for a given key/dlt.
	166	*/
	167	struct pfil_head *
	168	pfil_head_get(int type, u_long val)
	169	{
	170	struct pfil_head *ph;
	171
94171836 SZ	172	LIST_FOREACH(ph, &pfil_head_list, ph_list) {
94171836 SZ	173	if (ph->ph_type == type && ph->ph_un.phu_val == val)
9e99d0a2 JR	174	break;
9e99d0a2 JR	175	}
9e99d0a2 JR	176	return (ph);
	177	}
	178
f0fad8e1	179	static void
002c1265	180	pfil_add_hook_dispatch(netmsg_t nmsg)
9e99d0a2	181	{
f0fad8e1 SZ	182	struct netmsg_pfil pfilmsg = (struct netmsg_pfil )nmsg;
	183	pfil_func_t func = pfilmsg->pfil_func;
	184	void *arg = pfilmsg->pfil_arg;
	185	int flags = pfilmsg->pfil_flags;
	186	struct pfil_head *ph = pfilmsg->pfil_ph;
d66da3ad SZ	187	const struct packet_filter_hook *pfh;
	188	pfil_list_t list_in = NULL, list_out = NULL;
	189	pfil_list_t old_list_in = NULL, old_list_out = NULL;
9e99d0a2 JR	190	int err = 0;
9e99d0a2 JR	191
d66da3ad SZ	192	/* This probably should not happen ... */
	193	if ((flags & (PFIL_IN \| PFIL_OUT)) == 0)
	194	goto reply; /* XXX panic? */
	195
	196	/*
	197	* If pfil hooks exist on any of the requested lists,
	198	* then bail out.
	199	*/
9e99d0a2	200	if (flags & PFIL_IN) {
d66da3ad SZ	201	pfh = pfil_list_find(ph->ph_in, func, arg);
	202	if (pfh != NULL) {
	203	err = EEXIST;
f0fad8e1	204	goto reply;
d66da3ad	205	}
9e99d0a2 JR	206	}
9e99d0a2 JR	207	if (flags & PFIL_OUT) {
d66da3ad SZ	208	pfh = pfil_list_find(ph->ph_out, func, arg);
	209	if (pfh != NULL) {
	210	err = EEXIST;
	211	goto reply;
9e99d0a2 JR	212	}
9e99d0a2 JR	213	}
d66da3ad SZ	214
	215	/*
	216	* Duplicate the requested lists, install new hooks
	217	* on the duplication
	218	*/
	219	if (flags & PFIL_IN) {
	220	list_in = pfil_list_alloc();
	221	pfil_list_dup(ph->ph_in, list_in, NULL);
	222	pfil_list_add(list_in, func, arg, flags & ~PFIL_OUT);
	223	}
	224	if (flags & PFIL_OUT) {
	225	list_out = pfil_list_alloc();
	226	pfil_list_dup(ph->ph_out, list_out, NULL);
	227	pfil_list_add(list_out, func, arg, flags & ~PFIL_IN);
	228	}
	229
	230	/*
	231	* Switch list pointers, but keep the old ones
	232	*/
	233	if (list_in != NULL) {
	234	old_list_in = ph->ph_in;
	235	ph->ph_in = list_in;
	236	}
	237	if (list_out != NULL) {
	238	old_list_out = ph->ph_out;
	239	ph->ph_out = list_out;
	240	}
	241
	242	/*
	243	* Wait until everyone has finished the old lists iteration
	244	*/
	245	netmsg_service_sync();
	246	ph->ph_hashooks = 1;
	247
	248	/*
	249	* Now it is safe to free the old lists, since no one sees it
	250	*/
	251	if (old_list_in != NULL)
	252	pfil_list_free(old_list_in);
	253	if (old_list_out != NULL)
	254	pfil_list_free(old_list_out);
f0fad8e1	255	reply:
002c1265	256	lwkt_replymsg(&nmsg->base.lmsg, err);
f0fad8e1 SZ	257	}
	258
	259	/*
	260	* pfil_add_hook() adds a function to the packet filter hook. the
	261	* flags are:
	262	* PFIL_IN call me on incoming packets
	263	* PFIL_OUT call me on outgoing packets
	264	* PFIL_ALL call me on all of the above
77e0b69a	265	* PFIL_MPSAFE call me without BGL
f0fad8e1 SZ	266	*/
	267	int
	268	pfil_add_hook(pfil_func_t func, void arg, int flags, struct pfil_head ph)
	269	{
	270	struct netmsg_pfil pfilmsg;
002c1265 MD	271	netmsg_base_t nmsg;
002c1265 MD	272	int error;
f0fad8e1	273
002c1265	274	nmsg = &pfilmsg.base;
48e7b118 MD	275	netmsg_init(nmsg, NULL, &curthread->td_msgport,
48e7b118 MD	276	0, pfil_add_hook_dispatch);
f0fad8e1 SZ	277	pfilmsg.pfil_func = func;
	278	pfilmsg.pfil_arg = arg;
	279	pfilmsg.pfil_flags = flags;
	280	pfilmsg.pfil_ph = ph;
	281
002c1265 MD	282	error = lwkt_domsg(PFIL_CFGPORT, &nmsg->lmsg, 0);
002c1265 MD	283	return error;
9e99d0a2 JR	284	}
9e99d0a2 JR	285
d66da3ad	286	static void
002c1265	287	pfil_remove_hook_dispatch(netmsg_t nmsg)
9e99d0a2	288	{
d66da3ad SZ	289	struct netmsg_pfil pfilmsg = (struct netmsg_pfil )nmsg;
	290	pfil_func_t func = pfilmsg->pfil_func;
	291	void *arg = pfilmsg->pfil_arg;
	292	int flags = pfilmsg->pfil_flags;
	293	struct pfil_head *ph = pfilmsg->pfil_ph;
	294	struct packet_filter_hook skip_in = NULL, skip_out = NULL;
	295	pfil_list_t list_in = NULL, list_out = NULL;
	296	pfil_list_t old_list_in = NULL, old_list_out = NULL;
	297	int err = 0;
f0fad8e1	298
d66da3ad SZ	299	/* This probably should not happen ... */
	300	if ((flags & (PFIL_IN \| PFIL_OUT)) == 0)
	301	goto reply; /* XXX panic? */
9e99d0a2 JR	302
9e99d0a2 JR	303	/*
d66da3ad SZ	304	* The pfil hook should exist on all requested lists,
d66da3ad SZ	305	* if not just bail out
9e99d0a2	306	*/
d66da3ad SZ	307	if (flags & PFIL_IN) {
	308	skip_in = pfil_list_find(ph->ph_in, func, arg);
	309	if (!skip_in) {
	310	err = ENOENT;
	311	goto reply;
	312	}
	313	}
	314	if (flags & PFIL_OUT) {
	315	skip_out = pfil_list_find(ph->ph_out, func, arg);
	316	if (!skip_out) {
	317	err = ENOENT;
	318	goto reply;
	319	}
9e99d0a2 JR	320	}
9e99d0a2 JR	321
d66da3ad SZ	322	/*
	323	* Duplicate the requested lists, but the pfil hook to
	324	* be deleted is not copied
	325	*/
	326	if (flags & PFIL_IN) {
	327	KKASSERT(skip_in != NULL);
	328	list_in = pfil_list_alloc();
	329	pfil_list_dup(ph->ph_in, list_in, skip_in);
	330	}
	331	if (flags & PFIL_OUT) {
	332	KKASSERT(skip_out != NULL);
	333	list_out = pfil_list_alloc();
	334	pfil_list_dup(ph->ph_out, list_out, skip_out);
	335	}
9e99d0a2 JR	336
9e99d0a2 JR	337	/*
d66da3ad	338	* Switch list pointers, but keep the old ones
9e99d0a2	339	*/
d66da3ad SZ	340	if (list_in != NULL) {
	341	old_list_in = ph->ph_in;
	342	ph->ph_in = list_in;
	343	}
	344	if (list_out != NULL) {
	345	old_list_out = ph->ph_out;
	346	ph->ph_out = list_out;
	347	}
9e99d0a2	348
d66da3ad SZ	349	/*
	350	* Wait until everyone has finished the old lists iteration
	351	*/
	352	if (TAILQ_EMPTY(ph->ph_in) && TAILQ_EMPTY(ph->ph_out))
	353	ph->ph_hashooks = 0;
	354	netmsg_service_sync();
f0fad8e1	355
d66da3ad SZ	356	/*
	357	* Now it is safe to free the old lists, since no one sees it
	358	*/
	359	if (old_list_in != NULL)
	360	pfil_list_free(old_list_in);
	361	if (old_list_out != NULL)
	362	pfil_list_free(old_list_out);
	363	reply:
002c1265	364	lwkt_replymsg(&nmsg->base.lmsg, err);
f0fad8e1 SZ	365	}
f0fad8e1 SZ	366
9e99d0a2 JR	367	/*
	368	* pfil_remove_hook removes a specific function from the packet filter
	369	* hook list.
	370	*/
	371	int
3bc01464	372	pfil_remove_hook(pfil_func_t func, void arg, int flags, struct pfil_head ph)
9e99d0a2	373	{
f0fad8e1	374	struct netmsg_pfil pfilmsg;
002c1265	375	netmsg_base_t nmsg;
9e99d0a2	376
002c1265	377	nmsg = &pfilmsg.base;
48e7b118 MD	378	netmsg_init(nmsg, NULL, &curthread->td_msgport,
48e7b118 MD	379	0, pfil_remove_hook_dispatch);
f0fad8e1 SZ	380	pfilmsg.pfil_func = func;
	381	pfilmsg.pfil_arg = arg;
	382	pfilmsg.pfil_flags = flags;
	383	pfilmsg.pfil_ph = ph;
	384
002c1265	385	return lwkt_domsg(PFIL_CFGPORT, &nmsg->lmsg, 0);
9e99d0a2 JR	386	}
9e99d0a2 JR	387
d66da3ad SZ	388	static void
d66da3ad SZ	389	pfil_list_add(pfil_list_t list, pfil_func_t func, void arg, int flags)
9e99d0a2 JR	390	{
9e99d0a2 JR	391	struct packet_filter_hook *pfh;
afabe90c	392
f0fad8e1 SZ	393	KKASSERT(&curthread->td_msgport == PFIL_CFGPORT);
f0fad8e1 SZ	394
d66da3ad SZ	395	pfh = kmalloc(sizeof(*pfh), M_IFADDR, M_WAITOK);
	396
	397	pfh->pfil_func = func;
	398	pfh->pfil_arg = arg;
77d9cd11	399	pfh->pfil_flags = flags;
d66da3ad SZ	400
	401	/*
	402	* Insert the input list in reverse order of the output list
	403	* so that the same path is followed in or out of the kernel.
	404	*/
	405	if (flags & PFIL_IN)
	406	TAILQ_INSERT_HEAD(list, pfh, pfil_link);
	407	else
	408	TAILQ_INSERT_TAIL(list, pfh, pfil_link);
	409	}
	410
	411	static void
	412	pfil_list_dup(const pfil_list_t from, pfil_list_t to,
	413	const struct packet_filter_hook *skip)
	414	{
	415	struct packet_filter_hook pfh_to, pfh_from;
	416
	417	KKASSERT(&curthread->td_msgport == PFIL_CFGPORT);
	418	KKASSERT(TAILQ_EMPTY(to));
	419
	420	TAILQ_FOREACH(pfh_from, from, pfil_link) {
	421	if (pfh_from == skip)
	422	continue;
	423
	424	pfh_to = kmalloc(sizeof(*pfh_to), M_IFADDR, M_WAITOK);
	425	bcopy(pfh_from, pfh_to, sizeof(*pfh_to));
	426
	427	TAILQ_INSERT_TAIL(to, pfh_to, pfil_link);
	428	}
	429	}
	430
	431	static pfil_list_t *
	432	pfil_list_alloc(void)
	433	{
	434	pfil_list_t *list;
	435
	436	list = kmalloc(sizeof(*list), M_IFADDR, M_WAITOK);
	437	TAILQ_INIT(list);
	438	return list;
	439	}
	440
	441	static void
	442	pfil_list_free(pfil_list_t *list)
	443	{
	444	struct packet_filter_hook *pfh;
	445
	446	while ((pfh = TAILQ_FIRST(list)) != NULL) {
	447	TAILQ_REMOVE(list, pfh, pfil_link);
	448	kfree(pfh, M_IFADDR);
	449	}
	450	kfree(list, M_IFADDR);
	451	}
	452
	453	static struct packet_filter_hook *
	454	pfil_list_find(const pfil_list_t list, pfil_func_t func, const void arg)
	455	{
	456	struct packet_filter_hook *pfh;
	457
	458	KKASSERT(&curthread->td_msgport == PFIL_CFGPORT);
9e99d0a2	459
94171836	460	TAILQ_FOREACH(pfh, list, pfil_link) {
d66da3ad SZ	461	if (pfh->pfil_func == func && pfh->pfil_arg == arg)
d66da3ad SZ	462	return pfh;
9e99d0a2	463	}
d66da3ad	464	return NULL;
9e99d0a2	465	}