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
|
/*
* Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
*
* 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.
*
* Development of this code funded by Astaro AG (http://www.astaro.com/)
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/netlink.h>
#include <linux/netfilter.h>
#include <linux/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables.h>
// FIXME:
#include <net/ipv6.h>
struct nft_exthdr {
u8 type;
u8 offset;
u8 len;
enum nft_registers dreg:8;
};
static void nft_exthdr_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
struct nft_exthdr *priv = nft_expr_priv(expr);
u32 *dest = ®s->data[priv->dreg];
unsigned int offset = 0;
int err;
if (pkt->skb->protocol != htons(ETH_P_IPV6))
goto err;
err = ipv6_find_hdr(pkt->skb, &offset, priv->type, NULL, NULL);
if (err < 0)
goto err;
offset += priv->offset;
dest[priv->len / NFT_REG32_SIZE] = 0;
if (skb_copy_bits(pkt->skb, offset, dest, priv->len) < 0)
goto err;
return;
err:
regs->verdict.code = NFT_BREAK;
}
static const struct nla_policy nft_exthdr_policy[NFTA_EXTHDR_MAX + 1] = {
[NFTA_EXTHDR_DREG] = { .type = NLA_U32 },
[NFTA_EXTHDR_TYPE] = { .type = NLA_U8 },
[NFTA_EXTHDR_OFFSET] = { .type = NLA_U32 },
[NFTA_EXTHDR_LEN] = { .type = NLA_U32 },
};
static int nft_exthdr_init(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nlattr * const tb[])
{
struct nft_exthdr *priv = nft_expr_priv(expr);
if (tb[NFTA_EXTHDR_DREG] == NULL ||
tb[NFTA_EXTHDR_TYPE] == NULL ||
tb[NFTA_EXTHDR_OFFSET] == NULL ||
tb[NFTA_EXTHDR_LEN] == NULL)
return -EINVAL;
priv->type = nla_get_u8(tb[NFTA_EXTHDR_TYPE]);
priv->offset = ntohl(nla_get_be32(tb[NFTA_EXTHDR_OFFSET]));
priv->len = ntohl(nla_get_be32(tb[NFTA_EXTHDR_LEN]));
priv->dreg = nft_parse_register(tb[NFTA_EXTHDR_DREG]);
return nft_validate_register_store(ctx, priv->dreg, NULL,
NFT_DATA_VALUE, priv->len);
}
static int nft_exthdr_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
const struct nft_exthdr *priv = nft_expr_priv(expr);
if (nft_dump_register(skb, NFTA_EXTHDR_DREG, priv->dreg))
goto nla_put_failure;
if (nla_put_u8(skb, NFTA_EXTHDR_TYPE, priv->type))
goto nla_put_failure;
if (nla_put_be32(skb, NFTA_EXTHDR_OFFSET, htonl(priv->offset)))
goto nla_put_failure;
if (nla_put_be32(skb, NFTA_EXTHDR_LEN, htonl(priv->len)))
goto nla_put_failure;
return 0;
nla_put_failure:
return -1;
}
static struct nft_expr_type nft_exthdr_type;
static const struct nft_expr_ops nft_exthdr_ops = {
.type = &nft_exthdr_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_exthdr)),
.eval = nft_exthdr_eval,
.init = nft_exthdr_init,
.dump = nft_exthdr_dump,
};
static struct nft_expr_type nft_exthdr_type __read_mostly = {
.name = "exthdr",
.ops = &nft_exthdr_ops,
.policy = nft_exthdr_policy,
.maxattr = NFTA_EXTHDR_MAX,
.owner = THIS_MODULE,
};
static int __init nft_exthdr_module_init(void)
{
return nft_register_expr(&nft_exthdr_type);
}
static void __exit nft_exthdr_module_exit(void)
{
nft_unregister_expr(&nft_exthdr_type);
}
module_init(nft_exthdr_module_init);
module_exit(nft_exthdr_module_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
MODULE_ALIAS_NFT_EXPR("exthdr");
|
