xref: /freebsd/sys/net/pfil.h (revision 7ef62cebc2f965b0f640263e179276928885e33d)
1 /*	$FreeBSD$ */
2 /*	$NetBSD: pfil.h,v 1.22 2003/06/23 12:57:08 martin Exp $	*/
3 
4 /*-
5  * SPDX-License-Identifier: BSD-3-Clause
6  *
7  * Copyright (c) 2019 Gleb Smirnoff <glebius@FreeBSD.org>
8  * Copyright (c) 1996 Matthew R. Green
9  * All rights reserved.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. The name of the author may not be used to endorse or promote products
20  *    derived from this software without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
23  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
25  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
26  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #ifndef _NET_PFIL_H_
36 #define _NET_PFIL_H_
37 
38 #include <sys/ioccom.h>
39 
40 enum pfil_types {
41 	PFIL_TYPE_IP4,
42 	PFIL_TYPE_IP6,
43 	PFIL_TYPE_ETHERNET,
44 };
45 
46 #define	MAXPFILNAME	64
47 
48 struct pfilioc_head {
49 	char		pio_name[MAXPFILNAME];
50 	int		pio_nhooksin;
51 	int		pio_nhooksout;
52 	enum pfil_types	pio_type;
53 };
54 
55 struct pfilioc_hook {
56 	char		pio_module[MAXPFILNAME];
57 	char		pio_ruleset[MAXPFILNAME];
58 	int		pio_flags;
59 	enum pfil_types pio_type;
60 };
61 
62 struct pfilioc_list {
63 	u_int			 pio_nheads;
64 	u_int			 pio_nhooks;
65 	struct pfilioc_head	*pio_heads;
66 	struct pfilioc_hook	*pio_hooks;
67 };
68 
69 struct pfilioc_link {
70 	char		pio_name[MAXPFILNAME];
71 	char		pio_module[MAXPFILNAME];
72 	char		pio_ruleset[MAXPFILNAME];
73 	int		pio_flags;
74 };
75 
76 #define	PFILDEV			"pfil"
77 #define	PFILIOC_LISTHEADS	_IOWR('P', 1, struct pfilioc_list)
78 #define	PFILIOC_LISTHOOKS	_IOWR('P', 2, struct pfilioc_list)
79 #define	PFILIOC_LINK		_IOW('P', 3, struct pfilioc_link)
80 
81 #define	PFIL_IN		0x00010000
82 #define	PFIL_OUT	0x00020000
83 #define	PFIL_FWD	0x00040000
84 #define	PFIL_DIR(f)	((f) & (PFIL_IN|PFIL_OUT))
85 #define	PFIL_HEADPTR	0x00100000
86 #define	PFIL_HOOKPTR	0x00200000
87 #define	PFIL_APPEND	0x00400000
88 #define	PFIL_UNLINK	0x00800000
89 
90 #ifdef _KERNEL
91 struct mbuf;
92 struct ifnet;
93 struct inpcb;
94 
95 typedef enum {
96 	PFIL_PASS = 0,
97 	PFIL_DROPPED,
98 	PFIL_CONSUMED,
99 	PFIL_REALLOCED,
100 } pfil_return_t;
101 
102 typedef	pfil_return_t	(*pfil_mbuf_chk_t)(struct mbuf **, struct ifnet *, int,
103 			    void *, struct inpcb *);
104 typedef pfil_return_t	(*pfil_mem_chk_t)(void *, u_int, int, struct ifnet *,
105 			    void *, struct mbuf **);
106 
107 /*
108  * A pfil head is created by a packet intercept point.
109  *
110  * A pfil hook is created by a packet filter.
111  *
112  * Hooks are chained on heads.  Historically some hooking happens
113  * automatically, e.g. ipfw(4), pf(4) and ipfilter(4) would register
114  * theirselves on IPv4 and IPv6 input/output.
115  */
116 
117 typedef struct pfil_hook *	pfil_hook_t;
118 typedef struct pfil_head *	pfil_head_t;
119 
120 /*
121  * Give us a chance to modify pfil_xxx_args structures in future.
122  */
123 #define	PFIL_VERSION	2
124 
125 /* Argument structure used by packet filters to register themselves. */
126 struct pfil_hook_args {
127 	int		 pa_version;
128 	int		 pa_flags;
129 	enum pfil_types	 pa_type;
130 	pfil_mbuf_chk_t	 pa_mbuf_chk;
131 	pfil_mem_chk_t	 pa_mem_chk;
132 	void		*pa_ruleset;
133 	const char	*pa_modname;
134 	const char	*pa_rulname;
135 };
136 
137 /* Public functions for pfil hook management by packet filters. */
138 pfil_hook_t	pfil_add_hook(struct pfil_hook_args *);
139 void		pfil_remove_hook(pfil_hook_t);
140 
141 /* Argument structure used by ioctl() and packet filters to set filters. */
142 struct pfil_link_args {
143 	int		pa_version;
144 	int		pa_flags;
145 	union {
146 		const char	*pa_headname;
147 		pfil_head_t	 pa_head;
148 	};
149 	union {
150 		struct {
151 			const char	*pa_modname;
152 			const char	*pa_rulname;
153 		};
154 		pfil_hook_t	 pa_hook;
155 	};
156 };
157 
158 /* Public function to configure filter chains.  Used by ioctl() and filters. */
159 int	pfil_link(struct pfil_link_args *);
160 
161 /* Argument structure used by inspection points to register themselves. */
162 struct pfil_head_args {
163 	int		 pa_version;
164 	int		 pa_flags;
165 	enum pfil_types	 pa_type;
166 	const char	*pa_headname;
167 };
168 
169 /* Public functions for pfil head management by inspection points. */
170 pfil_head_t	pfil_head_register(struct pfil_head_args *);
171 void		pfil_head_unregister(pfil_head_t);
172 
173 /* Public functions to run the packet inspection by inspection points. */
174 int	pfil_mem_in(struct pfil_head *, void *, u_int, struct ifnet *,
175     struct mbuf **);
176 int	pfil_mem_out(struct pfil_head *, void *, u_int, struct ifnet *,
177     struct mbuf **);
178 int	pfil_mbuf_in(struct pfil_head *, struct mbuf **, struct ifnet *,
179     struct inpcb *inp);
180 int	pfil_mbuf_out(struct pfil_head *, struct mbuf **, struct ifnet *,
181     struct inpcb *inp);
182 int	pfil_mbuf_fwd(struct pfil_head *, struct mbuf **, struct ifnet *,
183     struct inpcb *);
184 
185 /*
186  * Minimally exposed structure to avoid function call in case of absence
187  * of any filters by protocols and macros to do the check.
188  */
189 struct _pfil_head {
190 	int	head_nhooksin;
191 	int	head_nhooksout;
192 };
193 #define	PFIL_HOOKED_IN(p) (((struct _pfil_head *)(p))->head_nhooksin > 0)
194 #define	PFIL_HOOKED_OUT(p) (((struct _pfil_head *)(p))->head_nhooksout > 0)
195 
196 #endif /* _KERNEL */
197 #endif /* _NET_PFIL_H_ */
198