xref: /freebsd/sys/net/bpf_jitter.c (revision 195ebc7e9e4b129de810833791a19dfb4349d6a9)
1 /*-
2  * Copyright (C) 2002-2003 NetGroup, Politecnico di Torino (Italy)
3  * Copyright (C) 2005-2008 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 
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
34 
35 #ifdef _KERNEL
36 #include "opt_bpf.h"
37 
38 #include <sys/param.h>
39 #include <sys/kernel.h>
40 #include <sys/malloc.h>
41 #include <sys/mbuf.h>
42 #include <sys/sysctl.h>
43 #else
44 #include <stdlib.h>
45 #include <string.h>
46 #include <sys/types.h>
47 #endif
48 
49 #include <net/bpf.h>
50 #include <net/bpf_jitter.h>
51 
52 bpf_filter_func	bpf_jit_compile(struct bpf_insn *, u_int, int *);
53 
54 static u_int	bpf_jit_accept_all(u_char *, u_int, u_int);
55 
56 #ifdef _KERNEL
57 MALLOC_DEFINE(M_BPFJIT, "BPF_JIT", "BPF JIT compiler");
58 
59 SYSCTL_NODE(_net, OID_AUTO, bpf_jitter, CTLFLAG_RW, 0, "BPF JIT compiler");
60 int bpf_jitter_enable = 1;
61 SYSCTL_INT(_net_bpf_jitter, OID_AUTO, enable, CTLFLAG_RW,
62     &bpf_jitter_enable, 0, "enable BPF JIT compiler");
63 
64 bpf_jit_filter *
65 bpf_jitter(struct bpf_insn *fp, int nins)
66 {
67 	bpf_jit_filter *filter;
68 
69 	/* Allocate the filter structure */
70 	filter = (struct bpf_jit_filter *)malloc(sizeof(*filter),
71 	    M_BPFJIT, M_NOWAIT | M_ZERO);
72 	if (filter == NULL)
73 		return (NULL);
74 
75 	/* No filter means accept all */
76 	if (fp == NULL || nins == 0) {
77 		filter->func = bpf_jit_accept_all;
78 		return (filter);
79 	}
80 
81 	/* Create the binary */
82 	if ((filter->func = bpf_jit_compile(fp, nins, filter->mem)) == NULL) {
83 		free(filter, M_BPFJIT);
84 		return (NULL);
85 	}
86 
87 	return (filter);
88 }
89 
90 void
91 bpf_destroy_jit_filter(bpf_jit_filter *filter)
92 {
93 
94 	if (filter->func != bpf_jit_accept_all)
95 		free(filter->func, M_BPFJIT);
96 	free(filter, M_BPFJIT);
97 }
98 #else
99 bpf_jit_filter *
100 bpf_jitter(struct bpf_insn *fp, int nins)
101 {
102 	bpf_jit_filter *filter;
103 
104 	/* Allocate the filter structure */
105 	filter = (struct bpf_jit_filter *)malloc(sizeof(*filter));
106 	if (filter == NULL)
107 		return (NULL);
108 	memset(filter, 0, sizeof(*filter));
109 
110 	/* No filter means accept all */
111 	if (fp == NULL || nins == 0) {
112 		filter->func = bpf_jit_accept_all;
113 		return (filter);
114 	}
115 
116 	/* Create the binary */
117 	if ((filter->func = bpf_jit_compile(fp, nins, filter->mem)) == NULL) {
118 		free(filter);
119 		return (NULL);
120 	}
121 
122 	return (filter);
123 }
124 
125 void
126 bpf_destroy_jit_filter(bpf_jit_filter *filter)
127 {
128 
129 	if (filter->func != bpf_jit_accept_all)
130 		free(filter->func);
131 	free(filter);
132 }
133 #endif
134 
135 static u_int
136 bpf_jit_accept_all(__unused u_char *p, __unused u_int wirelen,
137     __unused u_int buflen)
138 {
139 
140 	return ((u_int)-1);
141 }
142