bpf_jitter.c revision 182376 
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: head/sys/net/bpf_jitter.c 182376 2008-08-28 16:40:51Z jkim $");
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
52bpf_filter_func	bpf_jit_compile(struct bpf_insn *, u_int, int *);
53
54static u_int	bpf_jit_accept_all(u_char *, u_int, u_int);
55
56#ifdef _KERNEL
57MALLOC_DEFINE(M_BPFJIT, "BPF_JIT", "BPF JIT compiler");
58
59SYSCTL_NODE(_net, OID_AUTO, bpf_jitter, CTLFLAG_RW, 0, "BPF JIT compiler");
60int bpf_jitter_enable = 1;
61SYSCTL_INT(_net_bpf_jitter, OID_AUTO, enable, CTLFLAG_RW,
62    &bpf_jitter_enable, 0, "enable BPF JIT compiler");
63
64bpf_jit_filter *
65bpf_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
90void
91bpf_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
99bpf_jit_filter *
100bpf_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
125void
126bpf_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
135static u_int
136bpf_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