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96518518 PM |
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 | ||
21 | struct nft_exthdr { | |
22 | u8 type; | |
23 | u8 offset; | |
24 | u8 len; | |
25 | enum nft_registers dreg:8; | |
26 | }; | |
27 | ||
28 | static 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]; | |
540436c8 | 34 | unsigned int offset = 0; |
96518518 PM |
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; | |
45 | err: | |
46 | data[NFT_REG_VERDICT].verdict = NFT_BREAK; | |
47 | } | |
48 | ||
49 | static 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 | ||
56 | static 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 | ||
83 | static 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 | ||
97 | nla_put_failure: | |
98 | return -1; | |
99 | } | |
100 | ||
ef1f7df9 PM |
101 | static struct nft_expr_type nft_exthdr_type; |
102 | static const struct nft_expr_ops nft_exthdr_ops = { | |
103 | .type = &nft_exthdr_type, | |
96518518 | 104 | .size = NFT_EXPR_SIZE(sizeof(struct nft_exthdr)), |
96518518 PM |
105 | .eval = nft_exthdr_eval, |
106 | .init = nft_exthdr_init, | |
107 | .dump = nft_exthdr_dump, | |
ef1f7df9 PM |
108 | }; |
109 | ||
110 | static struct nft_expr_type nft_exthdr_type __read_mostly = { | |
111 | .name = "exthdr", | |
112 | .ops = &nft_exthdr_ops, | |
96518518 PM |
113 | .policy = nft_exthdr_policy, |
114 | .maxattr = NFTA_EXTHDR_MAX, | |
ef1f7df9 | 115 | .owner = THIS_MODULE, |
96518518 PM |
116 | }; |
117 | ||
118 | static int __init nft_exthdr_module_init(void) | |
119 | { | |
ef1f7df9 | 120 | return nft_register_expr(&nft_exthdr_type); |
96518518 PM |
121 | } |
122 | ||
123 | static void __exit nft_exthdr_module_exit(void) | |
124 | { | |
ef1f7df9 | 125 | nft_unregister_expr(&nft_exthdr_type); |
96518518 PM |
126 | } |
127 | ||
128 | module_init(nft_exthdr_module_init); | |
129 | module_exit(nft_exthdr_module_exit); | |
130 | ||
131 | MODULE_LICENSE("GPL"); | |
132 | MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); | |
133 | MODULE_ALIAS_NFT_EXPR("exthdr"); |