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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> | |
13 | ||
14 | #include <linux/netfilter/xt_bpf.h> | |
15 | #include <linux/netfilter/x_tables.h> | |
16 | ||
17 | MODULE_AUTHOR("Willem de Bruijn <willemb@google.com>"); | |
18 | MODULE_DESCRIPTION("Xtables: BPF filter match"); | |
19 | MODULE_LICENSE("GPL"); | |
20 | MODULE_ALIAS("ipt_bpf"); | |
21 | MODULE_ALIAS("ip6t_bpf"); | |
22 | ||
23 | static int bpf_mt_check(const struct xt_mtchk_param *par) | |
24 | { | |
25 | struct xt_bpf_info *info = par->matchinfo; | |
b1fcd35c | 26 | struct sock_fprog_kern program; |
e6f30c73 WB |
27 | |
28 | program.len = info->bpf_program_num_elem; | |
b1fcd35c DB |
29 | program.filter = info->bpf_program; |
30 | ||
7ae457c1 | 31 | if (bpf_prog_create(&info->filter, &program)) { |
e6f30c73 WB |
32 | pr_info("bpf: check failed: parse error\n"); |
33 | return -EINVAL; | |
34 | } | |
35 | ||
36 | return 0; | |
37 | } | |
38 | ||
39 | static bool bpf_mt(const struct sk_buff *skb, struct xt_action_param *par) | |
40 | { | |
41 | const struct xt_bpf_info *info = par->matchinfo; | |
42 | ||
7ae457c1 | 43 | return BPF_PROG_RUN(info->filter, skb); |
e6f30c73 WB |
44 | } |
45 | ||
46 | static void bpf_mt_destroy(const struct xt_mtdtor_param *par) | |
47 | { | |
48 | const struct xt_bpf_info *info = par->matchinfo; | |
7ae457c1 | 49 | bpf_prog_destroy(info->filter); |
e6f30c73 WB |
50 | } |
51 | ||
52 | static struct xt_match bpf_mt_reg __read_mostly = { | |
53 | .name = "bpf", | |
54 | .revision = 0, | |
55 | .family = NFPROTO_UNSPEC, | |
56 | .checkentry = bpf_mt_check, | |
57 | .match = bpf_mt, | |
58 | .destroy = bpf_mt_destroy, | |
59 | .matchsize = sizeof(struct xt_bpf_info), | |
60 | .me = THIS_MODULE, | |
61 | }; | |
62 | ||
63 | static int __init bpf_mt_init(void) | |
64 | { | |
65 | return xt_register_match(&bpf_mt_reg); | |
66 | } | |
67 | ||
68 | static void __exit bpf_mt_exit(void) | |
69 | { | |
70 | xt_unregister_match(&bpf_mt_reg); | |
71 | } | |
72 | ||
73 | module_init(bpf_mt_init); | |
74 | module_exit(bpf_mt_exit); |