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8#include <linux/kernel.h>
9#include <linux/init.h>
10#include <linux/module.h>
11#include <linux/netlink.h>
12#include <linux/netfilter.h>
13#include <linux/netfilter/nf_tables.h>
14#include <net/netfilter/nf_tables_core.h>
15#include <net/netfilter/nf_tables.h>
16
17struct nft_bitwise {
18 enum nft_registers sreg:8;
19 enum nft_registers dreg:8;
20 u8 len;
21 struct nft_data mask;
22 struct nft_data xor;
23};
24
25void nft_bitwise_eval(const struct nft_expr *expr,
26 struct nft_regs *regs, const struct nft_pktinfo *pkt)
27{
28 const struct nft_bitwise *priv = nft_expr_priv(expr);
29 const u32 *src = ®s->data[priv->sreg];
30 u32 *dst = ®s->data[priv->dreg];
31 unsigned int i;
32
33 for (i = 0; i < DIV_ROUND_UP(priv->len, 4); i++)
34 dst[i] = (src[i] & priv->mask.data[i]) ^ priv->xor.data[i];
35}
36
37static const struct nla_policy nft_bitwise_policy[NFTA_BITWISE_MAX + 1] = {
38 [NFTA_BITWISE_SREG] = { .type = NLA_U32 },
39 [NFTA_BITWISE_DREG] = { .type = NLA_U32 },
40 [NFTA_BITWISE_LEN] = { .type = NLA_U32 },
41 [NFTA_BITWISE_MASK] = { .type = NLA_NESTED },
42 [NFTA_BITWISE_XOR] = { .type = NLA_NESTED },
43};
44
45static int nft_bitwise_init(const struct nft_ctx *ctx,
46 const struct nft_expr *expr,
47 const struct nlattr * const tb[])
48{
49 struct nft_bitwise *priv = nft_expr_priv(expr);
50 struct nft_data_desc d1, d2;
51 u32 len;
52 int err;
53
54 if (tb[NFTA_BITWISE_SREG] == NULL ||
55 tb[NFTA_BITWISE_DREG] == NULL ||
56 tb[NFTA_BITWISE_LEN] == NULL ||
57 tb[NFTA_BITWISE_MASK] == NULL ||
58 tb[NFTA_BITWISE_XOR] == NULL)
59 return -EINVAL;
60
61 err = nft_parse_u32_check(tb[NFTA_BITWISE_LEN], U8_MAX, &len);
62 if (err < 0)
63 return err;
64
65 priv->len = len;
66
67 priv->sreg = nft_parse_register(tb[NFTA_BITWISE_SREG]);
68 err = nft_validate_register_load(priv->sreg, priv->len);
69 if (err < 0)
70 return err;
71
72 priv->dreg = nft_parse_register(tb[NFTA_BITWISE_DREG]);
73 err = nft_validate_register_store(ctx, priv->dreg, NULL,
74 NFT_DATA_VALUE, priv->len);
75 if (err < 0)
76 return err;
77
78 err = nft_data_init(NULL, &priv->mask, sizeof(priv->mask), &d1,
79 tb[NFTA_BITWISE_MASK]);
80 if (err < 0)
81 return err;
82 if (d1.len != priv->len) {
83 err = -EINVAL;
84 goto err1;
85 }
86
87 err = nft_data_init(NULL, &priv->xor, sizeof(priv->xor), &d2,
88 tb[NFTA_BITWISE_XOR]);
89 if (err < 0)
90 goto err1;
91 if (d2.len != priv->len) {
92 err = -EINVAL;
93 goto err2;
94 }
95
96 return 0;
97err2:
98 nft_data_release(&priv->xor, d2.type);
99err1:
100 nft_data_release(&priv->mask, d1.type);
101 return err;
102}
103
104static int nft_bitwise_dump(struct sk_buff *skb, const struct nft_expr *expr)
105{
106 const struct nft_bitwise *priv = nft_expr_priv(expr);
107
108 if (nft_dump_register(skb, NFTA_BITWISE_SREG, priv->sreg))
109 goto nla_put_failure;
110 if (nft_dump_register(skb, NFTA_BITWISE_DREG, priv->dreg))
111 goto nla_put_failure;
112 if (nla_put_be32(skb, NFTA_BITWISE_LEN, htonl(priv->len)))
113 goto nla_put_failure;
114
115 if (nft_data_dump(skb, NFTA_BITWISE_MASK, &priv->mask,
116 NFT_DATA_VALUE, priv->len) < 0)
117 goto nla_put_failure;
118
119 if (nft_data_dump(skb, NFTA_BITWISE_XOR, &priv->xor,
120 NFT_DATA_VALUE, priv->len) < 0)
121 goto nla_put_failure;
122
123 return 0;
124
125nla_put_failure:
126 return -1;
127}
128
129static const struct nft_expr_ops nft_bitwise_ops = {
130 .type = &nft_bitwise_type,
131 .size = NFT_EXPR_SIZE(sizeof(struct nft_bitwise)),
132 .eval = nft_bitwise_eval,
133 .init = nft_bitwise_init,
134 .dump = nft_bitwise_dump,
135};
136
137struct nft_expr_type nft_bitwise_type __read_mostly = {
138 .name = "bitwise",
139 .ops = &nft_bitwise_ops,
140 .policy = nft_bitwise_policy,
141 .maxattr = NFTA_BITWISE_MAX,
142 .owner = THIS_MODULE,
143};
144
