1 /* Xtables module to match packets using a BPF filter.
2 * Copyright 2013 Google Inc.
3 * Written by Willem de Bruijn <willemb@google.com>
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.
10 #include <linux/module.h>
11 #include <linux/skbuff.h>
12 #include <linux/filter.h>
13 #include <linux/bpf.h>
15 #include <linux/netfilter/xt_bpf.h>
16 #include <linux/netfilter/x_tables.h>
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");
24 static int __bpf_mt_check_bytecode(struct sock_filter
*insns
, __u16 len
,
25 struct bpf_prog
**ret
)
27 struct sock_fprog_kern program
;
30 program
.filter
= insns
;
32 if (bpf_prog_create(ret
, &program
)) {
33 pr_info("bpf: check failed: parse error\n");
40 static int __bpf_mt_check_fd(int fd
, struct bpf_prog
**ret
)
42 struct bpf_prog
*prog
;
44 prog
= bpf_prog_get_type(fd
, BPF_PROG_TYPE_SOCKET_FILTER
);
52 static int bpf_mt_check(const struct xt_mtchk_param
*par
)
54 struct xt_bpf_info
*info
= par
->matchinfo
;
56 return __bpf_mt_check_bytecode(info
->bpf_program
,
57 info
->bpf_program_num_elem
,
61 static int bpf_mt_check_v1(const struct xt_mtchk_param
*par
)
63 struct xt_bpf_info_v1
*info
= par
->matchinfo
;
65 if (info
->mode
== XT_BPF_MODE_BYTECODE
)
66 return __bpf_mt_check_bytecode(info
->bpf_program
,
67 info
->bpf_program_num_elem
,
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
);
76 static bool bpf_mt(const struct sk_buff
*skb
, struct xt_action_param
*par
)
78 const struct xt_bpf_info
*info
= par
->matchinfo
;
80 return BPF_PROG_RUN(info
->filter
, skb
);
83 static bool bpf_mt_v1(const struct sk_buff
*skb
, struct xt_action_param
*par
)
85 const struct xt_bpf_info_v1
*info
= par
->matchinfo
;
87 return !!bpf_prog_run_save_cb(info
->filter
, (struct sk_buff
*) skb
);
90 static void bpf_mt_destroy(const struct xt_mtdtor_param
*par
)
92 const struct xt_bpf_info
*info
= par
->matchinfo
;
94 bpf_prog_destroy(info
->filter
);
97 static void bpf_mt_destroy_v1(const struct xt_mtdtor_param
*par
)
99 const struct xt_bpf_info_v1
*info
= par
->matchinfo
;
101 bpf_prog_destroy(info
->filter
);
104 static struct xt_match bpf_mt_reg
[] __read_mostly
= {
108 .family
= NFPROTO_UNSPEC
,
109 .checkentry
= bpf_mt_check
,
111 .destroy
= bpf_mt_destroy
,
112 .matchsize
= sizeof(struct xt_bpf_info
),
113 .usersize
= offsetof(struct xt_bpf_info
, filter
),
119 .family
= NFPROTO_UNSPEC
,
120 .checkentry
= bpf_mt_check_v1
,
122 .destroy
= bpf_mt_destroy_v1
,
123 .matchsize
= sizeof(struct xt_bpf_info_v1
),
124 .usersize
= offsetof(struct xt_bpf_info_v1
, filter
),
129 static int __init
bpf_mt_init(void)
131 return xt_register_matches(bpf_mt_reg
, ARRAY_SIZE(bpf_mt_reg
));
134 static void __exit
bpf_mt_exit(void)
136 xt_unregister_matches(bpf_mt_reg
, ARRAY_SIZE(bpf_mt_reg
));
139 module_init(bpf_mt_init
);
140 module_exit(bpf_mt_exit
);