]>
Commit | Line | Data |
---|---|---|
e6f30c73 WB |
1 | /* Xtables module to match packets using a BPF filter. |
2 | * Copyright 2013 Google Inc. | |
3 | * Written by Willem de Bruijn <willemb@google.com> | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License version 2 as | |
7 | * published by the Free Software Foundation. | |
8 | */ | |
9 | ||
10 | #include <linux/module.h> | |
11 | #include <linux/skbuff.h> | |
12 | #include <linux/filter.h> | |
2c16d603 | 13 | #include <linux/bpf.h> |
e6f30c73 WB |
14 | |
15 | #include <linux/netfilter/xt_bpf.h> | |
16 | #include <linux/netfilter/x_tables.h> | |
17 | ||
18 | MODULE_AUTHOR("Willem de Bruijn <willemb@google.com>"); | |
19 | MODULE_DESCRIPTION("Xtables: BPF filter match"); | |
20 | MODULE_LICENSE("GPL"); | |
21 | MODULE_ALIAS("ipt_bpf"); | |
22 | MODULE_ALIAS("ip6t_bpf"); | |
23 | ||
2c16d603 WB |
24 | static int __bpf_mt_check_bytecode(struct sock_filter *insns, __u16 len, |
25 | struct bpf_prog **ret) | |
e6f30c73 | 26 | { |
b1fcd35c | 27 | struct sock_fprog_kern program; |
e6f30c73 | 28 | |
2c16d603 WB |
29 | program.len = len; |
30 | program.filter = insns; | |
b1fcd35c | 31 | |
2c16d603 | 32 | if (bpf_prog_create(ret, &program)) { |
e6f30c73 WB |
33 | pr_info("bpf: check failed: parse error\n"); |
34 | return -EINVAL; | |
35 | } | |
36 | ||
37 | return 0; | |
38 | } | |
39 | ||
2c16d603 WB |
40 | static int __bpf_mt_check_fd(int fd, struct bpf_prog **ret) |
41 | { | |
42 | struct bpf_prog *prog; | |
43 | ||
44 | prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER); | |
45 | if (IS_ERR(prog)) | |
46 | return PTR_ERR(prog); | |
47 | ||
48 | *ret = prog; | |
49 | return 0; | |
50 | } | |
51 | ||
52 | static int bpf_mt_check(const struct xt_mtchk_param *par) | |
53 | { | |
54 | struct xt_bpf_info *info = par->matchinfo; | |
55 | ||
56 | return __bpf_mt_check_bytecode(info->bpf_program, | |
57 | info->bpf_program_num_elem, | |
58 | &info->filter); | |
59 | } | |
60 | ||
61 | static int bpf_mt_check_v1(const struct xt_mtchk_param *par) | |
62 | { | |
63 | struct xt_bpf_info_v1 *info = par->matchinfo; | |
64 | ||
65 | if (info->mode == XT_BPF_MODE_BYTECODE) | |
66 | return __bpf_mt_check_bytecode(info->bpf_program, | |
67 | info->bpf_program_num_elem, | |
68 | &info->filter); | |
69 | else if (info->mode == XT_BPF_MODE_FD_PINNED || | |
70 | info->mode == XT_BPF_MODE_FD_ELF) | |
71 | return __bpf_mt_check_fd(info->fd, &info->filter); | |
72 | else | |
73 | return -EINVAL; | |
74 | } | |
75 | ||
e6f30c73 WB |
76 | static bool bpf_mt(const struct sk_buff *skb, struct xt_action_param *par) |
77 | { | |
78 | const struct xt_bpf_info *info = par->matchinfo; | |
79 | ||
7ae457c1 | 80 | return BPF_PROG_RUN(info->filter, skb); |
e6f30c73 WB |
81 | } |
82 | ||
2c16d603 WB |
83 | static bool bpf_mt_v1(const struct sk_buff *skb, struct xt_action_param *par) |
84 | { | |
85 | const struct xt_bpf_info_v1 *info = par->matchinfo; | |
86 | ||
87 | return !!bpf_prog_run_save_cb(info->filter, (struct sk_buff *) skb); | |
88 | } | |
89 | ||
e6f30c73 WB |
90 | static void bpf_mt_destroy(const struct xt_mtdtor_param *par) |
91 | { | |
92 | const struct xt_bpf_info *info = par->matchinfo; | |
2c16d603 WB |
93 | |
94 | bpf_prog_destroy(info->filter); | |
95 | } | |
96 | ||
97 | static void bpf_mt_destroy_v1(const struct xt_mtdtor_param *par) | |
98 | { | |
99 | const struct xt_bpf_info_v1 *info = par->matchinfo; | |
100 | ||
7ae457c1 | 101 | bpf_prog_destroy(info->filter); |
e6f30c73 WB |
102 | } |
103 | ||
2c16d603 WB |
104 | static struct xt_match bpf_mt_reg[] __read_mostly = { |
105 | { | |
106 | .name = "bpf", | |
107 | .revision = 0, | |
108 | .family = NFPROTO_UNSPEC, | |
109 | .checkentry = bpf_mt_check, | |
110 | .match = bpf_mt, | |
111 | .destroy = bpf_mt_destroy, | |
112 | .matchsize = sizeof(struct xt_bpf_info), | |
ec231890 | 113 | .usersize = offsetof(struct xt_bpf_info, filter), |
2c16d603 WB |
114 | .me = THIS_MODULE, |
115 | }, | |
116 | { | |
117 | .name = "bpf", | |
118 | .revision = 1, | |
119 | .family = NFPROTO_UNSPEC, | |
120 | .checkentry = bpf_mt_check_v1, | |
121 | .match = bpf_mt_v1, | |
122 | .destroy = bpf_mt_destroy_v1, | |
123 | .matchsize = sizeof(struct xt_bpf_info_v1), | |
ec231890 | 124 | .usersize = offsetof(struct xt_bpf_info_v1, filter), |
2c16d603 WB |
125 | .me = THIS_MODULE, |
126 | }, | |
e6f30c73 WB |
127 | }; |
128 | ||
129 | static int __init bpf_mt_init(void) | |
130 | { | |
2c16d603 | 131 | return xt_register_matches(bpf_mt_reg, ARRAY_SIZE(bpf_mt_reg)); |
e6f30c73 WB |
132 | } |
133 | ||
134 | static void __exit bpf_mt_exit(void) | |
135 | { | |
2c16d603 | 136 | xt_unregister_matches(bpf_mt_reg, ARRAY_SIZE(bpf_mt_reg)); |
e6f30c73 WB |
137 | } |
138 | ||
139 | module_init(bpf_mt_init); | |
140 | module_exit(bpf_mt_exit); |