1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
|
/* Xtables module to match packets using a BPF filter.
* Copyright 2013 Google Inc.
* Written by Willem de Bruijn <willemb@google.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/module.h>
#include <linux/syscalls.h>
#include <linux/skbuff.h>
#include <linux/filter.h>
#include <linux/bpf.h>
#include <linux/netfilter/xt_bpf.h>
#include <linux/netfilter/x_tables.h>
MODULE_AUTHOR("Willem de Bruijn <willemb@google.com>");
MODULE_DESCRIPTION("Xtables: BPF filter match");
MODULE_LICENSE("GPL");
MODULE_ALIAS("ipt_bpf");
MODULE_ALIAS("ip6t_bpf");
static int __bpf_mt_check_bytecode(struct sock_filter *insns, __u16 len,
struct bpf_prog **ret)
{
struct sock_fprog_kern program;
if (len > XT_BPF_MAX_NUM_INSTR)
return -EINVAL;
program.len = len;
program.filter = insns;
if (bpf_prog_create(ret, &program)) {
pr_info("bpf: check failed: parse error\n");
return -EINVAL;
}
return 0;
}
static int __bpf_mt_check_fd(int fd, struct bpf_prog **ret)
{
struct bpf_prog *prog;
prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER);
if (IS_ERR(prog))
return PTR_ERR(prog);
*ret = prog;
return 0;
}
static int __bpf_mt_check_path(const char *path, struct bpf_prog **ret)
{
if (strnlen(path, XT_BPF_PATH_MAX) == XT_BPF_PATH_MAX)
return -EINVAL;
*ret = bpf_prog_get_type_path(path, BPF_PROG_TYPE_SOCKET_FILTER);
return PTR_ERR_OR_ZERO(*ret);
}
static int bpf_mt_check(const struct xt_mtchk_param *par)
{
struct xt_bpf_info *info = par->matchinfo;
return __bpf_mt_check_bytecode(info->bpf_program,
info->bpf_program_num_elem,
&info->filter);
}
static int bpf_mt_check_v1(const struct xt_mtchk_param *par)
{
struct xt_bpf_info_v1 *info = par->matchinfo;
if (info->mode == XT_BPF_MODE_BYTECODE)
return __bpf_mt_check_bytecode(info->bpf_program,
info->bpf_program_num_elem,
&info->filter);
else if (info->mode == XT_BPF_MODE_FD_ELF)
return __bpf_mt_check_fd(info->fd, &info->filter);
else if (info->mode == XT_BPF_MODE_PATH_PINNED)
return __bpf_mt_check_path(info->path, &info->filter);
else
return -EINVAL;
}
static bool bpf_mt(const struct sk_buff *skb, struct xt_action_param *par)
{
const struct xt_bpf_info *info = par->matchinfo;
return BPF_PROG_RUN(info->filter, skb);
}
static bool bpf_mt_v1(const struct sk_buff *skb, struct xt_action_param *par)
{
const struct xt_bpf_info_v1 *info = par->matchinfo;
return !!bpf_prog_run_save_cb(info->filter, (struct sk_buff *) skb);
}
static void bpf_mt_destroy(const struct xt_mtdtor_param *par)
{
const struct xt_bpf_info *info = par->matchinfo;
bpf_prog_destroy(info->filter);
}
static void bpf_mt_destroy_v1(const struct xt_mtdtor_param *par)
{
const struct xt_bpf_info_v1 *info = par->matchinfo;
bpf_prog_destroy(info->filter);
}
static struct xt_match bpf_mt_reg[] __read_mostly = {
{
.name = "bpf",
.revision = 0,
.family = NFPROTO_UNSPEC,
.checkentry = bpf_mt_check,
.match = bpf_mt,
.destroy = bpf_mt_destroy,
.matchsize = sizeof(struct xt_bpf_info),
.usersize = offsetof(struct xt_bpf_info, filter),
.me = THIS_MODULE,
},
{
.name = "bpf",
.revision = 1,
.family = NFPROTO_UNSPEC,
.checkentry = bpf_mt_check_v1,
.match = bpf_mt_v1,
.destroy = bpf_mt_destroy_v1,
.matchsize = sizeof(struct xt_bpf_info_v1),
.usersize = offsetof(struct xt_bpf_info_v1, filter),
.me = THIS_MODULE,
},
};
static int __init bpf_mt_init(void)
{
return xt_register_matches(bpf_mt_reg, ARRAY_SIZE(bpf_mt_reg));
}
static void __exit bpf_mt_exit(void)
{
xt_unregister_matches(bpf_mt_reg, ARRAY_SIZE(bpf_mt_reg));
}
module_init(bpf_mt_init);
module_exit(bpf_mt_exit);
|
