xref: /freebsd/sys/net/bpf_jitter.h (revision 1c05a6ea6b849ff95e539c31adea887c644a6a01)
1 /*-
2  * Copyright (C) 2002-2003 NetGroup, Politecnico di Torino (Italy)
3  * Copyright (C) 2005-2009 Jung-uk Kim <jkim@FreeBSD.org>
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  *
10  * 1. Redistributions of source code must retain the above copyright
11  * notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  * notice, this list of conditions and the following disclaimer in the
14  * documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the Politecnico di Torino nor the names of its
16  * contributors may be used to endorse or promote products derived from
17  * this software without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
23  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30  *
31  * $FreeBSD$
32  */
33 
34 #ifndef _NET_BPF_JITTER_H_
35 #define _NET_BPF_JITTER_H_
36 
37 #ifdef _KERNEL
38 MALLOC_DECLARE(M_BPFJIT);
39 #endif
40 
41 extern int bpf_jitter_enable;
42 
43 /*
44  * Prototype of a filtering function created by the jitter.
45  *
46  * The syntax and the meaning of the parameters is analogous to the one of
47  * bpf_filter(). Notice that the filter is not among the parameters because
48  * it is hardwired in the function.
49  */
50 typedef u_int (*bpf_filter_func)(u_char *, u_int, u_int);
51 
52 /* Structure describing a native filtering program created by the jitter. */
53 typedef struct bpf_jit_filter {
54 	/* The native filtering binary, in the form of a bpf_filter_func. */
55 	bpf_filter_func	func;
56 	size_t		size;
57 } bpf_jit_filter;
58 
59 /*
60  * BPF jitter, builds a machine function from a BPF program.
61  *
62  * param fp	The BPF pseudo-assembly filter that will be translated
63  *		into native code.
64  * param nins	Number of instructions of the input filter.
65  * return	The bpf_jit_filter structure containing the native filtering
66  *		binary.
67  *
68  * bpf_jitter allocates the buffers for the new native filter and
69  * then translates the program pointed by fp calling bpf_jit_compile().
70  */
71 bpf_jit_filter	*bpf_jitter(struct bpf_insn *fp, int nins);
72 
73 /*
74  * Deletes a filtering function that was previously created by bpf_jitter().
75  *
76  * param filter	The filter to destroy.
77  *
78  * This function frees the variuos buffers (code, memory, etc.) associated
79  * with a filtering function.
80  */
81 void		bpf_destroy_jit_filter(bpf_jit_filter *filter);
82 
83 /*
84  * Declarations for machine-dependent functions.
85  */
86 struct bpf_insn;
87 
88 bpf_filter_func	bpf_jit_compile(struct bpf_insn *, u_int, size_t *);
89 void		bpf_jit_free(void *, size_t);
90 
91 #endif	/* _NET_BPF_JITTER_H_ */
92