xref: /freebsd/sys/net/bpf_jitter.h (revision eb69d1f144a6fcc765d1b9d44a5ae8082353e70b)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (C) 2002-2003 NetGroup, Politecnico di Torino (Italy)
5  * Copyright (C) 2005-2009 Jung-uk Kim <jkim@FreeBSD.org>
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  *
12  * 1. Redistributions of source code must retain the above copyright
13  * notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  * notice, this list of conditions and the following disclaimer in the
16  * documentation and/or other materials provided with the distribution.
17  * 3. Neither the name of the Politecnico di Torino nor the names of its
18  * contributors may be used to endorse or promote products derived from
19  * this software without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
24  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
25  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
26  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
27  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
31  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32  *
33  * $FreeBSD$
34  */
35 
36 #ifndef _NET_BPF_JITTER_H_
37 #define _NET_BPF_JITTER_H_
38 
39 #ifdef _KERNEL
40 MALLOC_DECLARE(M_BPFJIT);
41 #endif
42 
43 extern int bpf_jitter_enable;
44 
45 /*
46  * Prototype of a filtering function created by the jitter.
47  *
48  * The syntax and the meaning of the parameters is analogous to the one of
49  * bpf_filter(). Notice that the filter is not among the parameters because
50  * it is hardwired in the function.
51  */
52 typedef u_int (*bpf_filter_func)(u_char *, u_int, u_int);
53 
54 /* Structure describing a native filtering program created by the jitter. */
55 typedef struct bpf_jit_filter {
56 	/* The native filtering binary, in the form of a bpf_filter_func. */
57 	bpf_filter_func	func;
58 	size_t		size;
59 } bpf_jit_filter;
60 
61 /*
62  * BPF jitter, builds a machine function from a BPF program.
63  *
64  * param fp	The BPF pseudo-assembly filter that will be translated
65  *		into native code.
66  * param nins	Number of instructions of the input filter.
67  * return	The bpf_jit_filter structure containing the native filtering
68  *		binary.
69  *
70  * bpf_jitter allocates the buffers for the new native filter and
71  * then translates the program pointed by fp calling bpf_jit_compile().
72  */
73 bpf_jit_filter	*bpf_jitter(struct bpf_insn *fp, int nins);
74 
75 /*
76  * Deletes a filtering function that was previously created by bpf_jitter().
77  *
78  * param filter	The filter to destroy.
79  *
80  * This function frees the variuos buffers (code, memory, etc.) associated
81  * with a filtering function.
82  */
83 void		bpf_destroy_jit_filter(bpf_jit_filter *filter);
84 
85 /*
86  * Declarations for machine-dependent functions.
87  */
88 struct bpf_insn;
89 
90 bpf_filter_func	bpf_jit_compile(struct bpf_insn *, u_int, size_t *);
91 void		bpf_jit_free(void *, size_t);
92 
93 #endif	/* _NET_BPF_JITTER_H_ */
94