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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
4 *
5 * Development of this code funded by Astaro AG (http://www.astaro.com/)
6 */
7
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#include <net/netfilter/nf_tables_offload.h>
17
18struct nft_bitwise {
19 enum nft_registers sreg:8;
20 enum nft_registers dreg:8;
21 enum nft_bitwise_ops op:8;
22 u8 len;
23 struct nft_data mask;
24 struct nft_data xor;
25 struct nft_data data;
26};
27
28static void nft_bitwise_eval_bool(u32 *dst, const u32 *src,
29 const struct nft_bitwise *priv)
30{
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 void nft_bitwise_eval_lshift(u32 *dst, const u32 *src,
38 const struct nft_bitwise *priv)
39{
40 u32 shift = priv->data.data[0];
41 unsigned int i;
42 u32 carry = 0;
43
44 for (i = DIV_ROUND_UP(priv->len, sizeof(u32)); i > 0; i--) {
45 dst[i - 1] = (src[i - 1] << shift) | carry;
46 carry = src[i - 1] >> (BITS_PER_TYPE(u32) - shift);
47 }
48}
49
50static void nft_bitwise_eval_rshift(u32 *dst, const u32 *src,
51 const struct nft_bitwise *priv)
52{
53 u32 shift = priv->data.data[0];
54 unsigned int i;
55 u32 carry = 0;
56
57 for (i = 0; i < DIV_ROUND_UP(priv->len, sizeof(u32)); i++) {
58 dst[i] = carry | (src[i] >> shift);
59 carry = src[i] << (BITS_PER_TYPE(u32) - shift);
60 }
61}
62
63void nft_bitwise_eval(const struct nft_expr *expr,
64 struct nft_regs *regs, const struct nft_pktinfo *pkt)
65{
66 const struct nft_bitwise *priv = nft_expr_priv(expr);
67 const u32 *src = ®s->data[priv->sreg];
68 u32 *dst = ®s->data[priv->dreg];
69
70 switch (priv->op) {
71 case NFT_BITWISE_BOOL:
72 nft_bitwise_eval_bool(dst, src, priv);
73 break;
74 case NFT_BITWISE_LSHIFT:
75 nft_bitwise_eval_lshift(dst, src, priv);
76 break;
77 case NFT_BITWISE_RSHIFT:
78 nft_bitwise_eval_rshift(dst, src, priv);
79 break;
80 }
81}
82
83static const struct nla_policy nft_bitwise_policy[NFTA_BITWISE_MAX + 1] = {
84 [NFTA_BITWISE_SREG] = { .type = NLA_U32 },
85 [NFTA_BITWISE_DREG] = { .type = NLA_U32 },
86 [NFTA_BITWISE_LEN] = { .type = NLA_U32 },
87 [NFTA_BITWISE_MASK] = { .type = NLA_NESTED },
88 [NFTA_BITWISE_XOR] = { .type = NLA_NESTED },
89 [NFTA_BITWISE_OP] = { .type = NLA_U32 },
90 [NFTA_BITWISE_DATA] = { .type = NLA_NESTED },
91};
92
93static int nft_bitwise_init_bool(struct nft_bitwise *priv,
94 const struct nlattr *const tb[])
95{
96 struct nft_data_desc mask, xor;
97 int err;
98
99 if (tb[NFTA_BITWISE_DATA])
100 return -EINVAL;
101
102 if (!tb[NFTA_BITWISE_MASK] ||
103 !tb[NFTA_BITWISE_XOR])
104 return -EINVAL;
105
106 err = nft_data_init(NULL, &priv->mask, sizeof(priv->mask), &mask,
107 tb[NFTA_BITWISE_MASK]);
108 if (err < 0)
109 return err;
110 if (mask.type != NFT_DATA_VALUE || mask.len != priv->len) {
111 err = -EINVAL;
112 goto err1;
113 }
114
115 err = nft_data_init(NULL, &priv->xor, sizeof(priv->xor), &xor,
116 tb[NFTA_BITWISE_XOR]);
117 if (err < 0)
118 goto err1;
119 if (xor.type != NFT_DATA_VALUE || xor.len != priv->len) {
120 err = -EINVAL;
121 goto err2;
122 }
123
124 return 0;
125err2:
126 nft_data_release(&priv->xor, xor.type);
127err1:
128 nft_data_release(&priv->mask, mask.type);
129 return err;
130}
131
132static int nft_bitwise_init_shift(struct nft_bitwise *priv,
133 const struct nlattr *const tb[])
134{
135 struct nft_data_desc d;
136 int err;
137
138 if (tb[NFTA_BITWISE_MASK] ||
139 tb[NFTA_BITWISE_XOR])
140 return -EINVAL;
141
142 if (!tb[NFTA_BITWISE_DATA])
143 return -EINVAL;
144
145 err = nft_data_init(NULL, &priv->data, sizeof(priv->data), &d,
146 tb[NFTA_BITWISE_DATA]);
147 if (err < 0)
148 return err;
149 if (d.type != NFT_DATA_VALUE || d.len != sizeof(u32) ||
150 priv->data.data[0] >= BITS_PER_TYPE(u32)) {
151 nft_data_release(&priv->data, d.type);
152 return -EINVAL;
153 }
154
155 return 0;
156}
157
158static int nft_bitwise_init(const struct nft_ctx *ctx,
159 const struct nft_expr *expr,
160 const struct nlattr * const tb[])
161{
162 struct nft_bitwise *priv = nft_expr_priv(expr);
163 u32 len;
164 int err;
165
166 if (!tb[NFTA_BITWISE_SREG] ||
167 !tb[NFTA_BITWISE_DREG] ||
168 !tb[NFTA_BITWISE_LEN])
169 return -EINVAL;
170
171 err = nft_parse_u32_check(tb[NFTA_BITWISE_LEN], U8_MAX, &len);
172 if (err < 0)
173 return err;
174
175 priv->len = len;
176
177 priv->sreg = nft_parse_register(tb[NFTA_BITWISE_SREG]);
178 err = nft_validate_register_load(priv->sreg, priv->len);
179 if (err < 0)
180 return err;
181
182 priv->dreg = nft_parse_register(tb[NFTA_BITWISE_DREG]);
183 err = nft_validate_register_store(ctx, priv->dreg, NULL,
184 NFT_DATA_VALUE, priv->len);
185 if (err < 0)
186 return err;
187
188 if (tb[NFTA_BITWISE_OP]) {
189 priv->op = ntohl(nla_get_be32(tb[NFTA_BITWISE_OP]));
190 switch (priv->op) {
191 case NFT_BITWISE_BOOL:
192 case NFT_BITWISE_LSHIFT:
193 case NFT_BITWISE_RSHIFT:
194 break;
195 default:
196 return -EOPNOTSUPP;
197 }
198 } else {
199 priv->op = NFT_BITWISE_BOOL;
200 }
201
202 switch(priv->op) {
203 case NFT_BITWISE_BOOL:
204 err = nft_bitwise_init_bool(priv, tb);
205 break;
206 case NFT_BITWISE_LSHIFT:
207 case NFT_BITWISE_RSHIFT:
208 err = nft_bitwise_init_shift(priv, tb);
209 break;
210 }
211
212 return err;
213}
214
215static int nft_bitwise_dump_bool(struct sk_buff *skb,
216 const struct nft_bitwise *priv)
217{
218 if (nft_data_dump(skb, NFTA_BITWISE_MASK, &priv->mask,
219 NFT_DATA_VALUE, priv->len) < 0)
220 return -1;
221
222 if (nft_data_dump(skb, NFTA_BITWISE_XOR, &priv->xor,
223 NFT_DATA_VALUE, priv->len) < 0)
224 return -1;
225
226 return 0;
227}
228
229static int nft_bitwise_dump_shift(struct sk_buff *skb,
230 const struct nft_bitwise *priv)
231{
232 if (nft_data_dump(skb, NFTA_BITWISE_DATA, &priv->data,
233 NFT_DATA_VALUE, sizeof(u32)) < 0)
234 return -1;
235 return 0;
236}
237
238static int nft_bitwise_dump(struct sk_buff *skb, const struct nft_expr *expr)
239{
240 const struct nft_bitwise *priv = nft_expr_priv(expr);
241 int err = 0;
242
243 if (nft_dump_register(skb, NFTA_BITWISE_SREG, priv->sreg))
244 return -1;
245 if (nft_dump_register(skb, NFTA_BITWISE_DREG, priv->dreg))
246 return -1;
247 if (nla_put_be32(skb, NFTA_BITWISE_LEN, htonl(priv->len)))
248 return -1;
249 if (nla_put_be32(skb, NFTA_BITWISE_OP, htonl(priv->op)))
250 return -1;
251
252 switch (priv->op) {
253 case NFT_BITWISE_BOOL:
254 err = nft_bitwise_dump_bool(skb, priv);
255 break;
256 case NFT_BITWISE_LSHIFT:
257 case NFT_BITWISE_RSHIFT:
258 err = nft_bitwise_dump_shift(skb, priv);
259 break;
260 }
261
262 return err;
263}
264
265static struct nft_data zero;
266
267static int nft_bitwise_offload(struct nft_offload_ctx *ctx,
268 struct nft_flow_rule *flow,
269 const struct nft_expr *expr)
270{
271 const struct nft_bitwise *priv = nft_expr_priv(expr);
272 struct nft_offload_reg *reg = &ctx->regs[priv->dreg];
273
274 if (priv->op != NFT_BITWISE_BOOL)
275 return -EOPNOTSUPP;
276
277 if (memcmp(&priv->xor, &zero, sizeof(priv->xor)) ||
278 priv->sreg != priv->dreg || priv->len != reg->len)
279 return -EOPNOTSUPP;
280
281 memcpy(®->mask, &priv->mask, sizeof(priv->mask));
282
283 return 0;
284}
285
286static const struct nft_expr_ops nft_bitwise_ops = {
287 .type = &nft_bitwise_type,
288 .size = NFT_EXPR_SIZE(sizeof(struct nft_bitwise)),
289 .eval = nft_bitwise_eval,
290 .init = nft_bitwise_init,
291 .dump = nft_bitwise_dump,
292 .offload = nft_bitwise_offload,
293};
294
295struct nft_expr_type nft_bitwise_type __read_mostly = {
296 .name = "bitwise",
297 .ops = &nft_bitwise_ops,
298 .policy = nft_bitwise_policy,
299 .maxattr = NFTA_BITWISE_MAX,
300 .owner = THIS_MODULE,
301};