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
17MODULE_AUTHOR("Willem de Bruijn <willemb@google.com>");
18MODULE_DESCRIPTION("Xtables: BPF filter match");
19MODULE_LICENSE("GPL");
20MODULE_ALIAS("ipt_bpf");
21MODULE_ALIAS("ip6t_bpf");
22
23static int bpf_mt_check(const struct xt_mtchk_param *par)
24{
25	struct xt_bpf_info *info = par->matchinfo;
26	struct sock_fprog_kern program;
27
28	program.len = info->bpf_program_num_elem;
29	program.filter = info->bpf_program;
30
31	if (bpf_prog_create(&info->filter, &program)) {
32		pr_info("bpf: check failed: parse error\n");
33		return -EINVAL;
34	}
35
36	return 0;
37}
38
39static bool bpf_mt(const struct sk_buff *skb, struct xt_action_param *par)
40{
41	const struct xt_bpf_info *info = par->matchinfo;
42
43	return BPF_PROG_RUN(info->filter, skb);
44}
45
46static void bpf_mt_destroy(const struct xt_mtdtor_param *par)
47{
48	const struct xt_bpf_info *info = par->matchinfo;
49	bpf_prog_destroy(info->filter);
50}
51
52static 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
63static int __init bpf_mt_init(void)
64{
65	return xt_register_match(&bpf_mt_reg);
66}
67
68static void __exit bpf_mt_exit(void)
69{
70	xt_unregister_match(&bpf_mt_reg);
71}
72
73module_init(bpf_mt_init);
74module_exit(bpf_mt_exit);
75