272 lines
6.9 KiB
C
272 lines
6.9 KiB
C
/* $NetBSD: pfil.c,v 1.27 2008/06/23 03:13:12 dyoung Exp $ */
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/*
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* Copyright (c) 1996 Matthew R. Green
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: pfil.c,v 1.27 2008/06/23 03:13:12 dyoung Exp $");
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#include <sys/param.h>
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#include <sys/errno.h>
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#include <sys/malloc.h>
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#include <sys/socket.h>
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#include <sys/socketvar.h>
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#include <sys/systm.h>
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#include <sys/proc.h>
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#include <sys/queue.h>
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#include <net/if.h>
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#include <net/pfil.h>
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static int pfil_list_add(pfil_list_t *,
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int (*)(void *, struct mbuf **, struct ifnet *, int), void *, int);
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static int pfil_list_remove(pfil_list_t *,
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int (*)(void *, struct mbuf **, struct ifnet *, int), void *);
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LIST_HEAD(, pfil_head) pfil_head_list =
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LIST_HEAD_INITIALIZER(&pfil_head_list);
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/*
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* pfil_run_hooks() runs the specified packet filter hooks.
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*/
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int
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pfil_run_hooks(struct pfil_head *ph, struct mbuf **mp, struct ifnet *ifp,
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int dir)
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{
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struct packet_filter_hook *pfh;
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struct mbuf *m = NULL;
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int rv = 0;
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if ((dir & PFIL_ALL) && mp)
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m = *mp;
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for (pfh = pfil_hook_get(dir, ph); pfh != NULL;
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pfh = TAILQ_NEXT(pfh, pfil_link)) {
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if (pfh->pfil_func != NULL) {
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if (pfh->pfil_flags & PFIL_ALL) {
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rv = (*pfh->pfil_func)(pfh->pfil_arg, &m, ifp,
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dir);
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if (rv != 0 || m == NULL)
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break;
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} else {
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rv = (*pfh->pfil_func)(pfh->pfil_arg, mp, ifp,
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dir);
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if (rv != 0)
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break;
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}
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}
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}
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if ((dir & PFIL_ALL) && mp)
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*mp = m;
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return (rv);
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}
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/*
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* pfil_head_register() registers a pfil_head with the packet filter
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* hook mechanism.
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*/
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int
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pfil_head_register(struct pfil_head *ph)
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{
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struct pfil_head *lph;
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LIST_FOREACH(lph, &pfil_head_list, ph_list) {
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if (ph->ph_type == lph->ph_type &&
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ph->ph_un.phu_val == lph->ph_un.phu_val)
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return EEXIST;
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}
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TAILQ_INIT(&ph->ph_in);
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TAILQ_INIT(&ph->ph_out);
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TAILQ_INIT(&ph->ph_ifaddr);
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TAILQ_INIT(&ph->ph_ifnetevent);
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LIST_INSERT_HEAD(&pfil_head_list, ph, ph_list);
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return (0);
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}
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/*
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* pfil_head_unregister() removes a pfil_head from the packet filter
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* hook mechanism.
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*/
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int
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pfil_head_unregister(struct pfil_head *pfh)
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{
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LIST_REMOVE(pfh, ph_list);
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return (0);
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}
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/*
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* pfil_head_get() returns the pfil_head for a given key/dlt.
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*/
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struct pfil_head *
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pfil_head_get(int type, u_long val)
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{
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struct pfil_head *ph;
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LIST_FOREACH(ph, &pfil_head_list, ph_list) {
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if (ph->ph_type == type && ph->ph_un.phu_val == val)
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break;
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}
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return (ph);
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}
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/*
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* pfil_add_hook() adds a function to the packet filter hook. the
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* flags are:
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* PFIL_IN call me on incoming packets
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* PFIL_OUT call me on outgoing packets
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* PFIL_ALL call me on all of the above
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* PFIL_IFADDR call me on interface reconfig (mbuf ** is ioctl #)
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* PFIL_IFNET call me on interface attach/detach
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* (mbuf ** is PFIL_IFNET_*)
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* PFIL_WAITOK OK to call malloc with M_WAITOK.
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*/
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int
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pfil_add_hook(int (*func)(void *, struct mbuf **, struct ifnet *, int),
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void *arg, int flags, struct pfil_head *ph)
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{
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int err = 0;
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if (flags & PFIL_IN) {
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err = pfil_list_add(&ph->ph_in, func, arg, flags & ~PFIL_OUT);
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if (err)
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return err;
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}
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if (flags & PFIL_OUT) {
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err = pfil_list_add(&ph->ph_out, func, arg, flags & ~PFIL_IN);
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if (err) {
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if (flags & PFIL_IN)
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pfil_list_remove(&ph->ph_in, func, arg);
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return err;
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}
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}
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if (flags & PFIL_IFADDR) {
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err = pfil_list_add(&ph->ph_ifaddr, func, arg, flags);
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if (err) {
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if (flags & PFIL_IN)
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pfil_list_remove(&ph->ph_in, func, arg);
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if (flags & PFIL_OUT)
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pfil_list_remove(&ph->ph_out, func, arg);
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return err;
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}
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}
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if (flags & PFIL_IFNET) {
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err = pfil_list_add(&ph->ph_ifnetevent, func, arg, flags);
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if (err) {
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if (flags & PFIL_IN)
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pfil_list_remove(&ph->ph_in, func, arg);
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if (flags & PFIL_OUT)
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pfil_list_remove(&ph->ph_out, func, arg);
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if (flags & PFIL_IFADDR)
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pfil_list_remove(&ph->ph_ifaddr, func, arg);
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return err;
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}
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}
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return 0;
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}
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static int
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pfil_list_add(pfil_list_t *list,
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int (*func)(void *, struct mbuf **, struct ifnet *, int), void *arg,
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int flags)
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{
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struct packet_filter_hook *pfh;
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/*
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* First make sure the hook is not already there.
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*/
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TAILQ_FOREACH(pfh, list, pfil_link) {
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if (pfh->pfil_func == func && pfh->pfil_arg == arg)
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return EEXIST;
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}
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pfh = (struct packet_filter_hook *)malloc(sizeof(*pfh), M_IFADDR,
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(flags & PFIL_WAITOK) ? M_WAITOK : M_NOWAIT);
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if (pfh == NULL)
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return ENOMEM;
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pfh->pfil_func = func;
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pfh->pfil_arg = arg;
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pfh->pfil_flags = flags;
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/*
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* insert the input list in reverse order of the output list
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* so that the same path is followed in or out of the kernel.
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*/
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if (flags & PFIL_IN)
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TAILQ_INSERT_HEAD(list, pfh, pfil_link);
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else
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TAILQ_INSERT_TAIL(list, pfh, pfil_link);
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return 0;
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}
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/*
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* pfil_remove_hook removes a specific function from the packet filter
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* hook list.
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*/
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int
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pfil_remove_hook(int (*func)(void *, struct mbuf **, struct ifnet *, int),
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void *arg, int flags, struct pfil_head *ph)
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{
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int err = 0;
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if (flags & PFIL_IN)
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err = pfil_list_remove(&ph->ph_in, func, arg);
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if ((err == 0) && (flags & PFIL_OUT))
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err = pfil_list_remove(&ph->ph_out, func, arg);
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if ((err == 0) && (flags & PFIL_IFADDR))
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err = pfil_list_remove(&ph->ph_ifaddr, func, arg);
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if ((err == 0) && (flags & PFIL_IFNET))
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err = pfil_list_remove(&ph->ph_ifnetevent, func, arg);
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return err;
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}
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/*
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* pfil_list_remove is an internal function that takes a function off the
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* specified list.
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*/
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static int
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pfil_list_remove(pfil_list_t *list,
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int (*func)(void *, struct mbuf **, struct ifnet *, int), void *arg)
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{
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struct packet_filter_hook *pfh;
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TAILQ_FOREACH(pfh, list, pfil_link) {
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if (pfh->pfil_func == func && pfh->pfil_arg == arg) {
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TAILQ_REMOVE(list, pfh, pfil_link);
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free(pfh, M_IFADDR);
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return 0;
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}
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}
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return ENOENT;
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}
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