b252313f0b
The KPI have been reviewed and cleansed of features that were planned back 20 years ago and never implemented. The pfil(9) internals have been made opaque to protocols with only returned types and function declarations exposed. The KPI is made more strict, but at the same time more extensible, as kernel uses same command structures that userland ioctl uses. In nutshell [KA]PI is about declaring filtering points, declaring filters and linking and unlinking them together. New [KA]PI makes it possible to reconfigure pfil(9) configuration: change order of hooks, rehook filter from one filtering point to a different one, disconnect a hook on output leaving it on input only, prepend/append a filter to existing list of filters. Now it possible for a single packet filter to provide multiple rulesets that may be linked to different points. Think of per-interface ACLs in Cisco or Juniper. None of existing packet filters yet support that, however limited usage is already possible, e.g. default ruleset can be moved to single interface, as soon as interface would pride their filtering points. Another future feature is possiblity to create pfil heads, that provide not an mbuf pointer but just a memory pointer with length. That would allow filtering at very early stages of a packet lifecycle, e.g. when packet has just been received by a NIC and no mbuf was yet allocated. Differential Revision: https://reviews.freebsd.org/D18951
193 lines
5.4 KiB
C
193 lines
5.4 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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} pfil_packet_t __attribute__((__transparent_union__));
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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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#endif /* _KERNEL */
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#endif /* _NET_PFIL_H_ */
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