c93410229c
PFIL_MEMPTR flag are intentionally providing a memory address that isn't aligned to pointer alignment. This is done to align an IPv4 or IPv6 header that is expected to follow Ethernet header. When we return PFIL_REALLOCED we store a pointer to allocated mbuf at this address. With this change the KPI changes to store the pointer at aligned address, which usually yields in +2 bytes. Provide two inlines: pfil_packet_align() to get aligned pfil_packet_t for a misaligned one pfil_mem2mbuf() to read out mbuf pointer from misaligned pfil_packet_t Provide function pfil_realloc(), not used yet, that would convert a memory pfil_packet_t to an mbuf one. Reported by: hps Reviewed by: hps, gallatin
215 lines
5.9 KiB
C
215 lines
5.9 KiB
C
/* $FreeBSD$ */
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/* $NetBSD: pfil.h,v 1.22 2003/06/23 12:57:08 martin Exp $ */
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/*-
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* SPDX-License-Identifier: BSD-3-Clause
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*
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* Copyright (c) 2019 Gleb Smirnoff <glebius@FreeBSD.org>
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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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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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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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#ifndef _NET_PFIL_H_
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#define _NET_PFIL_H_
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#include <sys/ioccom.h>
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enum pfil_types {
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PFIL_TYPE_IP4,
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PFIL_TYPE_IP6,
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PFIL_TYPE_ETHERNET,
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};
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#define MAXPFILNAME 64
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struct pfilioc_head {
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char pio_name[MAXPFILNAME];
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int pio_nhooksin;
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int pio_nhooksout;
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enum pfil_types pio_type;
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};
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struct pfilioc_hook {
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char pio_module[MAXPFILNAME];
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char pio_ruleset[MAXPFILNAME];
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int pio_flags;
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enum pfil_types pio_type;
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};
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struct pfilioc_list {
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u_int pio_nheads;
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u_int pio_nhooks;
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struct pfilioc_head *pio_heads;
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struct pfilioc_hook *pio_hooks;
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};
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struct pfilioc_link {
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char pio_name[MAXPFILNAME];
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char pio_module[MAXPFILNAME];
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char pio_ruleset[MAXPFILNAME];
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int pio_flags;
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};
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#define PFILDEV "pfil"
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#define PFILIOC_LISTHEADS _IOWR('P', 1, struct pfilioc_list)
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#define PFILIOC_LISTHOOKS _IOWR('P', 2, struct pfilioc_list)
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#define PFILIOC_LINK _IOW('P', 3, struct pfilioc_link)
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#define PFIL_IN 0x00010000
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#define PFIL_OUT 0x00020000
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#define PFIL_FWD 0x00040000
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#define PFIL_DIR(f) ((f) & (PFIL_IN|PFIL_OUT))
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#define PFIL_MEMPTR 0x00080000
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#define PFIL_HEADPTR 0x00100000
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#define PFIL_HOOKPTR 0x00200000
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#define PFIL_APPEND 0x00400000
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#define PFIL_UNLINK 0x00800000
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#define PFIL_LENMASK 0x0000ffff
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#define PFIL_LENGTH(f) ((f) & PFIL_LENMASK)
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#ifdef _KERNEL
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struct mbuf;
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struct ifnet;
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struct inpcb;
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typedef union {
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struct mbuf **m;
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void *mem;
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uintptr_t __ui;
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} pfil_packet_t __attribute__((__transparent_union__));
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static inline pfil_packet_t
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pfil_packet_align(pfil_packet_t p)
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{
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return ((pfil_packet_t ) (((uintptr_t)(p).mem +
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(_Alignof(void *) - 1)) & - _Alignof(void *)));
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}
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static inline struct mbuf *
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pfil_mem2mbuf(void *v)
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{
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return (*(struct mbuf **) (((uintptr_t)(v) +
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(_Alignof(void *) - 1)) & - _Alignof(void *)));
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}
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typedef enum {
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PFIL_PASS = 0,
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PFIL_DROPPED,
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PFIL_CONSUMED,
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PFIL_REALLOCED,
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} pfil_return_t;
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typedef pfil_return_t (*pfil_func_t)(pfil_packet_t, struct ifnet *, int,
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void *, struct inpcb *);
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/*
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* A pfil head is created by a packet intercept point.
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*
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* A pfil hook is created by a packet filter.
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*
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* Hooks are chained on heads. Historically some hooking happens
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* automatically, e.g. ipfw(4), pf(4) and ipfilter(4) would register
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* theirselves on IPv4 and IPv6 input/output.
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*/
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typedef struct pfil_hook * pfil_hook_t;
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typedef struct pfil_head * pfil_head_t;
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/*
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* Give us a chance to modify pfil_xxx_args structures in future.
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*/
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#define PFIL_VERSION 1
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/* Argument structure used by packet filters to register themselves. */
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struct pfil_hook_args {
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int pa_version;
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int pa_flags;
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enum pfil_types pa_type;
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pfil_func_t pa_func;
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void *pa_ruleset;
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const char *pa_modname;
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const char *pa_rulname;
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};
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/* Public functions for pfil hook management by packet filters. */
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pfil_hook_t pfil_add_hook(struct pfil_hook_args *);
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void pfil_remove_hook(pfil_hook_t);
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/* Argument structure used by ioctl() and packet filters to set filters. */
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struct pfil_link_args {
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int pa_version;
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int pa_flags;
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union {
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const char *pa_headname;
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pfil_head_t pa_head;
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};
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union {
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struct {
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const char *pa_modname;
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const char *pa_rulname;
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};
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pfil_hook_t pa_hook;
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};
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};
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/* Public function to configure filter chains. Used by ioctl() and filters. */
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int pfil_link(struct pfil_link_args *);
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/* Argument structure used by inspection points to register themselves. */
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struct pfil_head_args {
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int pa_version;
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int pa_flags;
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enum pfil_types pa_type;
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const char *pa_headname;
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};
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/* Public functions for pfil head management by inspection points. */
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pfil_head_t pfil_head_register(struct pfil_head_args *);
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void pfil_head_unregister(pfil_head_t);
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/* Public functions to run the packet inspection by inspection points. */
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int pfil_run_hooks(struct pfil_head *, pfil_packet_t, struct ifnet *, int,
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struct inpcb *inp);
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/*
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* Minimally exposed structure to avoid function call in case of absence
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* of any filters by protocols and macros to do the check.
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*/
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struct _pfil_head {
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int head_nhooksin;
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int head_nhooksout;
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};
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#define PFIL_HOOKED_IN(p) (((struct _pfil_head *)(p))->head_nhooksin > 0)
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#define PFIL_HOOKED_OUT(p) (((struct _pfil_head *)(p))->head_nhooksout > 0)
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/*
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* Alloc mbuf to be used instead of memory pointer.
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*/
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int pfil_realloc(pfil_packet_t *, int, struct ifnet *);
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#endif /* _KERNEL */
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#endif /* _NET_PFIL_H_ */
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