tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 * Development of this code funded by Astaro AG (http://www.astaro.com/)
9 */
10
11#include <linux/kernel.h>
12#include <linux/init.h>
13#include <linux/module.h>
14#include <linux/netlink.h>
15#include <linux/netfilter.h>
16#include <linux/netfilter/nf_tables.h>
17#include <net/netfilter/nf_tables.h>
18// FIXME:
19#include <net/ipv6.h>
20
21struct nft_exthdr {
22 u8 type;
23 u8 offset;
24 u8 len;
25 enum nft_registers dreg:8;
26};
27
28static void nft_exthdr_eval(const struct nft_expr *expr,
29 struct nft_data data[NFT_REG_MAX + 1],
30 const struct nft_pktinfo *pkt)
31{
32 struct nft_exthdr *priv = nft_expr_priv(expr);
33 struct nft_data *dest = &data[priv->dreg];
34 unsigned int offset = 0;
35 int err;
36
37 err = ipv6_find_hdr(pkt->skb, &offset, priv->type, NULL, NULL);
38 if (err < 0)
39 goto err;
40 offset += priv->offset;
41
42 if (skb_copy_bits(pkt->skb, offset, dest->data, priv->len) < 0)
43 goto err;
44 return;
45err:
46 data[NFT_REG_VERDICT].verdict = NFT_BREAK;
47}
48
49static const struct nla_policy nft_exthdr_policy[NFTA_EXTHDR_MAX + 1] = {
50 [NFTA_EXTHDR_DREG] = { .type = NLA_U32 },
51 [NFTA_EXTHDR_TYPE] = { .type = NLA_U8 },
52 [NFTA_EXTHDR_OFFSET] = { .type = NLA_U32 },
53 [NFTA_EXTHDR_LEN] = { .type = NLA_U32 },
54};
55
56static int nft_exthdr_init(const struct nft_ctx *ctx,
57 const struct nft_expr *expr,
58 const struct nlattr * const tb[])
59{
60 struct nft_exthdr *priv = nft_expr_priv(expr);
61 int err;
62
63 if (tb[NFTA_EXTHDR_DREG] == NULL ||
64 tb[NFTA_EXTHDR_TYPE] == NULL ||
65 tb[NFTA_EXTHDR_OFFSET] == NULL ||
66 tb[NFTA_EXTHDR_LEN] == NULL)
67 return -EINVAL;
68
69 priv->type = nla_get_u8(tb[NFTA_EXTHDR_TYPE]);
70 priv->offset = ntohl(nla_get_be32(tb[NFTA_EXTHDR_OFFSET]));
71 priv->len = ntohl(nla_get_be32(tb[NFTA_EXTHDR_LEN]));
72 if (priv->len == 0 ||
73 priv->len > FIELD_SIZEOF(struct nft_data, data))
74 return -EINVAL;
75
76 priv->dreg = ntohl(nla_get_be32(tb[NFTA_EXTHDR_DREG]));
77 err = nft_validate_output_register(priv->dreg);
78 if (err < 0)
79 return err;
80 return nft_validate_data_load(ctx, priv->dreg, NULL, NFT_DATA_VALUE);
81}
82
83static int nft_exthdr_dump(struct sk_buff *skb, const struct nft_expr *expr)
84{
85 const struct nft_exthdr *priv = nft_expr_priv(expr);
86
87 if (nla_put_be32(skb, NFTA_EXTHDR_DREG, htonl(priv->dreg)))
88 goto nla_put_failure;
89 if (nla_put_u8(skb, NFTA_EXTHDR_TYPE, priv->type))
90 goto nla_put_failure;
91 if (nla_put_be32(skb, NFTA_EXTHDR_OFFSET, htonl(priv->offset)))
92 goto nla_put_failure;
93 if (nla_put_be32(skb, NFTA_EXTHDR_LEN, htonl(priv->len)))
94 goto nla_put_failure;
95 return 0;
96
97nla_put_failure:
98 return -1;
99}
100
101static struct nft_expr_type nft_exthdr_type;
102static const struct nft_expr_ops nft_exthdr_ops = {
103 .type = &nft_exthdr_type,
104 .size = NFT_EXPR_SIZE(sizeof(struct nft_exthdr)),
105 .eval = nft_exthdr_eval,
106 .init = nft_exthdr_init,
107 .dump = nft_exthdr_dump,
108};
109
110static struct nft_expr_type nft_exthdr_type __read_mostly = {
111 .name = "exthdr",
112 .ops = &nft_exthdr_ops,
113 .policy = nft_exthdr_policy,
114 .maxattr = NFTA_EXTHDR_MAX,
115 .owner = THIS_MODULE,
116};
117
118static int __init nft_exthdr_module_init(void)
119{
120 return nft_register_expr(&nft_exthdr_type);
121}
122
123static void __exit nft_exthdr_module_exit(void)
124{
125 nft_unregister_expr(&nft_exthdr_type);
126}
127
128module_init(nft_exthdr_module_init);
129module_exit(nft_exthdr_module_exit);
130
131MODULE_LICENSE("GPL");
132MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
133MODULE_ALIAS_NFT_EXPR("exthdr");