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96518518 | 1 | /* |
ef1f7df9 | 2 | * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net> |
96518518 PM |
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_core.h> | |
18 | #include <net/netfilter/nf_tables.h> | |
19 | ||
20 | struct nft_cmp_expr { | |
21 | struct nft_data data; | |
22 | enum nft_registers sreg:8; | |
23 | u8 len; | |
24 | enum nft_cmp_ops op:8; | |
25 | }; | |
26 | ||
27 | static void nft_cmp_eval(const struct nft_expr *expr, | |
a55e22e9 | 28 | struct nft_regs *regs, |
96518518 PM |
29 | const struct nft_pktinfo *pkt) |
30 | { | |
31 | const struct nft_cmp_expr *priv = nft_expr_priv(expr); | |
32 | int d; | |
33 | ||
e562d860 | 34 | d = memcmp(®s->data[priv->sreg], &priv->data, priv->len); |
96518518 PM |
35 | switch (priv->op) { |
36 | case NFT_CMP_EQ: | |
37 | if (d != 0) | |
38 | goto mismatch; | |
39 | break; | |
40 | case NFT_CMP_NEQ: | |
41 | if (d == 0) | |
42 | goto mismatch; | |
43 | break; | |
44 | case NFT_CMP_LT: | |
45 | if (d == 0) | |
46 | goto mismatch; | |
47 | case NFT_CMP_LTE: | |
48 | if (d > 0) | |
49 | goto mismatch; | |
50 | break; | |
51 | case NFT_CMP_GT: | |
52 | if (d == 0) | |
53 | goto mismatch; | |
54 | case NFT_CMP_GTE: | |
55 | if (d < 0) | |
56 | goto mismatch; | |
57 | break; | |
58 | } | |
59 | return; | |
60 | ||
61 | mismatch: | |
a55e22e9 | 62 | regs->verdict.code = NFT_BREAK; |
96518518 PM |
63 | } |
64 | ||
65 | static const struct nla_policy nft_cmp_policy[NFTA_CMP_MAX + 1] = { | |
66 | [NFTA_CMP_SREG] = { .type = NLA_U32 }, | |
67 | [NFTA_CMP_OP] = { .type = NLA_U32 }, | |
68 | [NFTA_CMP_DATA] = { .type = NLA_NESTED }, | |
69 | }; | |
70 | ||
71 | static int nft_cmp_init(const struct nft_ctx *ctx, const struct nft_expr *expr, | |
72 | const struct nlattr * const tb[]) | |
73 | { | |
74 | struct nft_cmp_expr *priv = nft_expr_priv(expr); | |
75 | struct nft_data_desc desc; | |
76 | int err; | |
77 | ||
96518518 | 78 | err = nft_data_init(NULL, &priv->data, &desc, tb[NFTA_CMP_DATA]); |
cb7dbfd0 | 79 | BUG_ON(err < 0); |
96518518 | 80 | |
d07db988 PM |
81 | priv->sreg = ntohl(nla_get_be32(tb[NFTA_CMP_SREG])); |
82 | err = nft_validate_register_load(priv->sreg, desc.len); | |
83 | if (err < 0) | |
84 | return err; | |
85 | ||
86 | priv->op = ntohl(nla_get_be32(tb[NFTA_CMP_OP])); | |
96518518 PM |
87 | priv->len = desc.len; |
88 | return 0; | |
89 | } | |
90 | ||
91 | static int nft_cmp_dump(struct sk_buff *skb, const struct nft_expr *expr) | |
92 | { | |
93 | const struct nft_cmp_expr *priv = nft_expr_priv(expr); | |
94 | ||
95 | if (nla_put_be32(skb, NFTA_CMP_SREG, htonl(priv->sreg))) | |
96 | goto nla_put_failure; | |
97 | if (nla_put_be32(skb, NFTA_CMP_OP, htonl(priv->op))) | |
98 | goto nla_put_failure; | |
99 | ||
100 | if (nft_data_dump(skb, NFTA_CMP_DATA, &priv->data, | |
101 | NFT_DATA_VALUE, priv->len) < 0) | |
102 | goto nla_put_failure; | |
103 | return 0; | |
104 | ||
105 | nla_put_failure: | |
106 | return -1; | |
107 | } | |
108 | ||
ef1f7df9 PM |
109 | static struct nft_expr_type nft_cmp_type; |
110 | static const struct nft_expr_ops nft_cmp_ops = { | |
111 | .type = &nft_cmp_type, | |
96518518 | 112 | .size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_expr)), |
96518518 PM |
113 | .eval = nft_cmp_eval, |
114 | .init = nft_cmp_init, | |
115 | .dump = nft_cmp_dump, | |
ef1f7df9 PM |
116 | }; |
117 | ||
cb7dbfd0 PM |
118 | static int nft_cmp_fast_init(const struct nft_ctx *ctx, |
119 | const struct nft_expr *expr, | |
120 | const struct nlattr * const tb[]) | |
121 | { | |
122 | struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); | |
123 | struct nft_data_desc desc; | |
124 | struct nft_data data; | |
125 | u32 mask; | |
126 | int err; | |
127 | ||
cb7dbfd0 PM |
128 | err = nft_data_init(NULL, &data, &desc, tb[NFTA_CMP_DATA]); |
129 | BUG_ON(err < 0); | |
cb7dbfd0 | 130 | |
d07db988 PM |
131 | priv->sreg = ntohl(nla_get_be32(tb[NFTA_CMP_SREG])); |
132 | err = nft_validate_register_load(priv->sreg, desc.len); | |
133 | if (err < 0) | |
134 | return err; | |
135 | ||
136 | desc.len *= BITS_PER_BYTE; | |
b855d416 | 137 | mask = nft_cmp_fast_mask(desc.len); |
d07db988 | 138 | |
cb7dbfd0 PM |
139 | priv->data = data.data[0] & mask; |
140 | priv->len = desc.len; | |
141 | return 0; | |
142 | } | |
143 | ||
144 | static int nft_cmp_fast_dump(struct sk_buff *skb, const struct nft_expr *expr) | |
145 | { | |
146 | const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); | |
147 | struct nft_data data; | |
148 | ||
149 | if (nla_put_be32(skb, NFTA_CMP_SREG, htonl(priv->sreg))) | |
150 | goto nla_put_failure; | |
151 | if (nla_put_be32(skb, NFTA_CMP_OP, htonl(NFT_CMP_EQ))) | |
152 | goto nla_put_failure; | |
153 | ||
154 | data.data[0] = priv->data; | |
155 | if (nft_data_dump(skb, NFTA_CMP_DATA, &data, | |
156 | NFT_DATA_VALUE, priv->len / BITS_PER_BYTE) < 0) | |
157 | goto nla_put_failure; | |
158 | return 0; | |
159 | ||
160 | nla_put_failure: | |
161 | return -1; | |
162 | } | |
163 | ||
164 | const struct nft_expr_ops nft_cmp_fast_ops = { | |
165 | .type = &nft_cmp_type, | |
166 | .size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_fast_expr)), | |
167 | .eval = NULL, /* inlined */ | |
168 | .init = nft_cmp_fast_init, | |
169 | .dump = nft_cmp_fast_dump, | |
170 | }; | |
171 | ||
0ca743a5 PNA |
172 | static const struct nft_expr_ops * |
173 | nft_cmp_select_ops(const struct nft_ctx *ctx, const struct nlattr * const tb[]) | |
cb7dbfd0 PM |
174 | { |
175 | struct nft_data_desc desc; | |
176 | struct nft_data data; | |
cb7dbfd0 PM |
177 | enum nft_cmp_ops op; |
178 | int err; | |
179 | ||
180 | if (tb[NFTA_CMP_SREG] == NULL || | |
181 | tb[NFTA_CMP_OP] == NULL || | |
182 | tb[NFTA_CMP_DATA] == NULL) | |
183 | return ERR_PTR(-EINVAL); | |
184 | ||
cb7dbfd0 PM |
185 | op = ntohl(nla_get_be32(tb[NFTA_CMP_OP])); |
186 | switch (op) { | |
187 | case NFT_CMP_EQ: | |
188 | case NFT_CMP_NEQ: | |
189 | case NFT_CMP_LT: | |
190 | case NFT_CMP_LTE: | |
191 | case NFT_CMP_GT: | |
192 | case NFT_CMP_GTE: | |
193 | break; | |
194 | default: | |
195 | return ERR_PTR(-EINVAL); | |
196 | } | |
197 | ||
198 | err = nft_data_init(NULL, &data, &desc, tb[NFTA_CMP_DATA]); | |
199 | if (err < 0) | |
200 | return ERR_PTR(err); | |
201 | ||
202 | if (desc.len <= sizeof(u32) && op == NFT_CMP_EQ) | |
203 | return &nft_cmp_fast_ops; | |
204 | else | |
205 | return &nft_cmp_ops; | |
206 | } | |
207 | ||
ef1f7df9 PM |
208 | static struct nft_expr_type nft_cmp_type __read_mostly = { |
209 | .name = "cmp", | |
cb7dbfd0 | 210 | .select_ops = nft_cmp_select_ops, |
96518518 PM |
211 | .policy = nft_cmp_policy, |
212 | .maxattr = NFTA_CMP_MAX, | |
ef1f7df9 | 213 | .owner = THIS_MODULE, |
96518518 PM |
214 | }; |
215 | ||
216 | int __init nft_cmp_module_init(void) | |
217 | { | |
ef1f7df9 | 218 | return nft_register_expr(&nft_cmp_type); |
96518518 PM |
219 | } |
220 | ||
221 | void nft_cmp_module_exit(void) | |
222 | { | |
ef1f7df9 | 223 | nft_unregister_expr(&nft_cmp_type); |
96518518 | 224 | } |