bpf_jitter.c revision 182220 
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 182220 2008-08-26 21:06:31Z 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 <sys/types.h>
46#endif
47
48#include <net/bpf.h>
49#include <net/bpf_jitter.h>
50
51bpf_filter_func	bpf_jit_compile(struct bpf_insn *, u_int, int *);
52
53static u_int	bpf_jit_accept_all(u_char *, u_int, u_int);
54
55#ifdef _KERNEL
56MALLOC_DEFINE(M_BPFJIT, "BPF_JIT", "BPF JIT compiler");
57
58SYSCTL_NODE(_net, OID_AUTO, bpf_jitter, CTLFLAG_RW, 0, "BPF JIT compiler");
59int bpf_jitter_enable = 1;
60SYSCTL_INT(_net_bpf_jitter, OID_AUTO, enable, CTLFLAG_RW,
61    &bpf_jitter_enable, 0, "enable BPF JIT compiler");
62
63bpf_jit_filter *
64bpf_jitter(struct bpf_insn *fp, int nins)
65{
66	bpf_jit_filter *filter;
67
68	/* Allocate the filter structure */
69	filter = (struct bpf_jit_filter *)malloc(sizeof(*filter),
70	    M_BPFJIT, M_NOWAIT);
71	if (filter == NULL)
72		return (NULL);
73
74	/* No filter means accept all */
75	if (fp == NULL || nins == 0) {
76		filter->func = bpf_jit_accept_all;
77		return (filter);
78	}
79
80	/* Create the binary */
81	if ((filter->func = bpf_jit_compile(fp, nins, filter->mem)) == NULL) {
82		free(filter, M_BPFJIT);
83		return (NULL);
84	}
85
86	return (filter);
87}
88
89void
90bpf_destroy_jit_filter(bpf_jit_filter *filter)
91{
92
93	if (filter->func != bpf_jit_accept_all)
94		free(filter->func, M_BPFJIT);
95	free(filter, M_BPFJIT);
96}
97#else
98bpf_jit_filter *
99bpf_jitter(struct bpf_insn *fp, int nins)
100{
101	bpf_jit_filter *filter;
102
103	/* Allocate the filter structure */
104	filter = (struct bpf_jit_filter *)malloc(sizeof(*filter));
105	if (filter == NULL)
106		return (NULL);
107
108	/* No filter means accept all */
109	if (fp == NULL || nins == 0) {
110		filter->func = bpf_jit_accept_all;
111		return (filter);
112	}
113
114	/* Create the binary */
115	if ((filter->func = bpf_jit_compile(fp, nins, filter->mem)) == NULL) {
116		free(filter);
117		return (NULL);
118	}
119
120	return (filter);
121}
122
123void
124bpf_destroy_jit_filter(bpf_jit_filter *filter)
125{
126
127	if (filter->func != bpf_jit_accept_all)
128		free(filter->func);
129	free(filter);
130}
131#endif
132
133static u_int
134bpf_jit_accept_all(__unused u_char *p, __unused u_int wirelen,
135    __unused u_int buflen)
136{
137
138	return ((u_int)-1);
139}
140